Dissertations / Theses on the topic 'Energy Awarene'
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CANALE, Laura. "About the impact of individual metering on the energy efficiency of residential buildings." Doctoral thesis, Università degli studi di Cassino, 2020. http://hdl.handle.net/11580/75194.
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Since 2002, the European Union has promoted individual metering of energy consumption as an effective tool to improve energy efficiency in buildings.
In 2012, the Energy Efficiency Directive has set mandatory the individual heat accounting in buildings when centralized heating/cooling systems are installed, when technically feasible and cost efficient.
As far, Member States of European Union adopted different approaches regarding this obligation, due to differences in their climatic conditions, building stocks characteristics and installed technologies but also to a lack of knowledge about the real impact of the use of such devices.
As a consequence, this measure has led to a series of technical, legal and consumer protection issues which still need to be solved. This thesis aims to address, with a multi-thematic approach, the issue of measuring thermal energy consumption in residential buildings. A number of four research questions have been investigated in order to answer to the main question: “What is the
impact of the use of energy metering devices in residential buildings?”.
To this aim, a number of six case studies were investigated to: i) evaluate the expected metrological performances of individual metering devices on-field; ii) assess the potential energy saving gainable through the use of individual metering devices in Mediterranean climates and analyse possible feedback strategies to enhance end-user awareness; iii) evaluate the potential impact of different energy policies on the outcome of this energy measure; iv) evaluate the performances of current methodologies applied for end-users’ profiling through individual metering.
Results of this thesis provide useful insights to researchers, designers and policy makers, filling some of the gaps highlighted in the existing scientific literature in all the analysed areas.
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Rasumov, Nikon. "Energy-aware adaptation." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607938.
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Sinha, Amit 1976. "Energy aware software." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/87158.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2000.Includes bibliographical references (leaves 58-60).
by Amit Sinha.
S.M.
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Lin, Gongqi. "Energy aware traffic engineering." Thesis, Curtin University, 2014. http://hdl.handle.net/20.500.11937/292.
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Over-provisioning of network resources, i.e., routers and links, provides a unique opportunity for energy aware traffic engineering. In the thesis, we design three heuristic approaches, i.e., SSPF, MSPF, and 2DP-SP to solve three proposed green routing problems, i.e., SP-EAR, MP-EAR, and EAR-2DP. Our simulation results show the trade-off between power savings and network performances, i.e., maximum link utilization, path length, and route reliability, when using green routings algorithms.
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Ejembi, Oche Omobamibo. "Enabling energy-awareness for internet video." Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/9768.
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Continuous improvements to the state of the art have made it easier to create, send and receive vast quantities of video over the Internet. Catalysed by these developments, video is now the largest, and fastest growing type of traffic on modern IP networks. In 2015, video was responsible for 70% of all traffic on the Internet, with an compound annual growth rate of 27%. On the other hand, concerns about the growing energy consumption of ICT in general, continue to rise. It is not surprising that there is a significant energy cost associated with these extensive video usage patterns. In this thesis, I examine the energy consumption of typical video configurations during decoding (playback) and encoding through empirical measurements on an experimental test-bed. I then make extrapolations to a global scale to show the opportunity for significant energy savings, achievable by simple modifications to these video configurations. Based on insights gained from these measurements, I propose a novel, energy-aware Quality of Experience (QoE) metric for digital video - the Energy - Video Quality Index (EnVI). Then, I present and evaluate vEQ-benchmark, a benchmarking and measurement tool for the purpose of generating EnVI scores. The tool enables fine-grained resource-usage analyses on video playback systems, and facilitates the creation of statistical models of power usage for these systems. I propose GreenDASH, an energy-aware extension of the existing Dynamic Adaptive Streaming over HTTP standard (DASH). GreenDASH incorporates relevant energy-usage and video quality information into the existing standard. It could enable dynamic, energy-aware adaptation for video in response to energy-usage and user ‘green' preferences. I also evaluate the subjective perception of such energy-aware, adaptive video streaming by means of a user study featuring 36 participants. I examine how video may be adapted to save energy without a significant impact on the Quality of Experience of these users. In summary, this thesis highlights the significant opportunities for energy savings if Internet users gain an awareness about their energy usage, and presents a technical discussion how this can be achieved by straightforward extensions to the current state of the art.
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Guyon, David. "Supporting energy-awareness for cloud users." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S037/document.
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Les centres de calcul cloud consomment d'importantes quantités d'énergie et il devient nécessaire de réduire leur consommation en raison des changements climatiques actuels. Bien que des propositions d'optimisations énergétiques existent, elles ne tiennent pas compte des utilisateurs finaux. Cette thèse propose d'inclure les utilisateurs cloud dans l'optimisation énergétique afin de réduire la consommation d'énergie des centres de calcul. L'inclusion se fait, dans un premier temps, en délivrant une information énergétique pour sensibiliser, puis dans un second temps, en fournissant des moyens d'action. Les contributions portent sur les couches cloud IaaS et PaaS. Nos résultats montrent que les utilisateurs tolérants à la variation des performances (e.g. retarder l'obtention de résultats) permettent de réduire la consommation d'énergie des centres de calculCloud datacenters consume large amounts of energy and it becomes necessary to reduce their consumption due to current climate changes. Although energy optimization propositions exist, they do not take into account end-users. This thesis proposes to include cloud users in the energy optimization as a means to reduce datacenters energy consumption. The inclusion is done, first, by delivering energy related information to raise awareness, and second, by providing means of actions. Contributions are located at IaaS and PaaS cloud layers. Our results show that users tolerant to performance variation (e.g. delay in obtaining execution results) allow to reduce datacenters energy consumption
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Vergara, Alonso Ekhiotz Jon. "Exploiting Energy Awareness in Mobile Communication." Licentiate thesis, Linköpings universitet, Programvara och system, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-98656.
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Although evolving mobile technologies bring millions of users closer to the vision of information anywhere-anytime, device battery depletions hamper the quality of experience to a great extent. The massive explosion of mobile applications with the ensuing data exchange over the cellular infrastructure is not only a blessing to the mobile user, but also has a price in terms of rapid discharge of the device battery. Wireless communication is a large contributor to the energy consumption. Thus, the current call for energy economy in mobile devices poses the challenge of reducing the energy consumption of wireless data transmissions at the user end by developing energy-efficient communication. This thesis addresses the energy efficiency of data transmission at the user end in the context of cellular networks. We argue that the design of energy-efficient solutions starts by energy awareness and propose EnergyBox, a parametrised tool that enables accurate and repeatable energy quantification at the user end using real data traffic traces as input. EnergyBox abstracts the underlying states for operation of the wireless interfaces and allows to estimate the energy consumption for different operator settings and device characteristics. Next, we devise an energy-efficient algorithm that schedules the packet transmissions at the user end based on the knowledge of the network parameters that impact the handset energy consumption. The solution focuses on the characteristics of a given traffic class with the lowest quality of service requirements. The cost of running the solution itself is studied showing that the proposed cross-layer scheduler uses a small amount of energy to significantly extend the battery lifetime at the cost of some added latency. Finally, the benefit of employing EnergyBox to systematically study the different design choices that developers face with respect to data transmissions of applications is shown in the context of location sharing services and instant messaging applications. The results show that quantifying energy consumption of communication patterns, protocols, and data formats can aid the design of tailor-made solutions with a significantly smaller energy footprint.
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Bokfors, Sofie. "Awareness on Solar Energy in Kenya." Thesis, KTH, Energiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-245193.
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Solar energy coupled with energy efficiency awareness can be an important step to achieving the final goal of having a sustainable environment in the country. Together with a good energy policy including regulations, this goal can be achieved as it will help consumers make more rational decisions when it comes to new technology. A key problem identified in this work is the lack of awareness and strict energy policies. The current funds put in place are not mobile and have not got to a large number of people. The government’s regulations on the other hand are not strict. This report aims to improve the current status by suggesting strategies to reach out to as many people as possible and educate them about solar energy options in Kenya. It aims to prepare to build a platform that creates awareness on solar energy, energy efficiency as well as the policies and finances needed to support their uptake. In order to build this platform, analysis has been done through research and meetings with stakeholders who have provided first-hand information in order to formulate the foundation to a future platform. The information gathered has then been used to explain and meet the challenges faced in solar energy in Kenya. The conclusion of this project was that majority of the people in Kenya lack required knowledge about solar energy. There is need to create awareness in solar energy.Solenergi i kombination med medvetenhet gällande energieffektivitet är ett viktigt steg för att uppnå det slutliga målet, som är att ha en hållbar utveckling gällande energi och miljö i Kenya. Tillsammans med en bra energipolitik som har tydliga regler, kan detta mål uppnås. Detta kommer att hjälpa konsumenterna att fatta mer rationella beslut när det gäller ny teknik. Ett nyckelproblem som identifieras i detta arbete är bristen på medvetenhet och även bristen av en strikt energipolitik. Kunskapen om solenergi och energieffektivitet har inte nått ut till majoriteten av människorna i Kenya. I dagsläget är lagarna gällande energi inte tillräckligt strikta. Denna rapport syftar till att förbättra den nuvarande situationen genom att föreslå strategier för att nå ut till maximalt antal invånare och utbilda dem om solenergialternativ. Rapporten syftar till att lägga en grund för att kunna bygga upp en plattform som skapar medvetenhet om solenergi och energieffektivitet, och vad som krävs politiskt och finansiellt för att stödja detta. För att kunna bygga upp denna plattform har analyser gjorts genom litteraturstudier och möten med intressenter som har bidragit med förstahandsinformation, detta för att kunna skapa grunden till den framtida plattformen. Informationen som samlats in har sedan använts för att förklara och för att försöka möta utmaningarna gällande solenergi i Kenya. Slutsatsen av detta projekt är att majoriteten invånarna i landet saknar nödvändig kunskap om solenergi. Det är därför viktigt att skapa medvetenhet gällande solenergi.
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Bokfors, Sofie. "Awareness on Solar Energy in Kenya." Thesis, KTH, Energiteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-250019.
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Solar energy coupled with energy efficiency awareness can be an important step to achieving thefinal goal of having a sustainable environment in the country. Together with a good energy policyincluding regulations, this goal can be achieved as it will help consumers make more rationaldecisions when it comes to new technology. A key problem identified in this work is the lack ofawareness and strict energy policies. The current funds put in place are not mobile and have not got to a large number of people. Thegovernment’s regulations on the other hand are not strict. This report aims to improve the currentstatus by suggesting strategies to reach out to as many people as possible and educate them aboutsolar energy options in Kenya. It aims to prepare to build a platform that creates awareness onsolar energy, energy efficiency as well as the policies and finances needed to support their uptake. In order to build this platform, analysis has been done through research and meetings withstakeholders who have provided first-hand information in order to formulate the foundation to afuture platform. The information gathered has then been used to explain and meet the challengesfaced in solar energy in Kenya. The conclusion of this project was that majority of the people inKenya lack required knowledge about solar energy. There is need to create awareness in solarenergy.
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Didioui, Amine. "Energy-aware transceiver for energy harvesting wireless sensor networks." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S056/document.
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Les progrès technologiques accomplis durant ces dernières décennies dans les domaines des microsystèmes et des radiocommunications nous permettent de réaliser des composants communicants miniaturisés à faible coût afin de constituer des réseaux de capteurs sans fil. Typiquement, chacun de ces composants intègre une ou plusieurs unités de mesures (capteur), une unité de traitement de données, une unité de communication radio et une batterie. De ce fait, un nouveau domaine de recherche s’est créé pour étudier le déploiement de ces réseaux afin d’offrir des solutions de surveillance et de contrôle à distance, notamment dans des environnements complexes ou inaccessibles. Les domaines d’application de ces capteurs sont très variés, allant de la domotique au militaire en passant par le médical et les infrastructures civiles. Souvent, ces applications impliquent des contraintes sévères en terme d’autonomie qui idéalement devrait atteindre plusieurs dizaines d’années. Pour atteindre cet objectif, il est à la fois nécessaire de réduire la consommation énergétique du nœud capteur et de trouver d’autres solutions d’alimentation en énergie pour le nœud. Pour adresser ce deuxième point, la récupération d’énergie à partir de l’environnement (solaire, vibratoire, thermique, etc.) semble représenter une solution idéale pour alimenter un nœud capteur, bien que celui-ci doive s’adapter aux faibles quantités d’énergie récupérées par ces systèmes, ainsi qu’à leurs variations et intermittences. Ces travaux de thèse s’intéressent donc à la problématique de la simulation et de la réduction de la consommation des nœuds de capteurs sans-fil et autonomes en énergie. Dans un premier temps, nous avons développé la plateforme HarvWSNet, un environnement de co-simulation alliant le simulateur de réseaux WSNet et Matlab permettant ainsi la modélisation précise et la simulation hétérogène des protocoles de communication (typiquement à événements discrets) et des systèmes de récupération d’énergie (qui possèdent typiquement un comportement à temps continu). Nous avons démontré que cette plateforme permet de réaliser très rapidement des études de pré-prototypage de scénarios applicatifs de déploiement et ainsi réduire le temps de conception de ces nouvelles technologies. Grâce à la modélisation précise des éléments du système de récupération d’énergie (batterie, supercapacité, etc.) permise par cette plateforme, nous avons étudié et évalué la durée de vie de déploiements à large échelle de réseaux de capteurs alimentés par des systèmes de récupération d’énergie (solaire et éolien). La deuxième contribution de cette thèse concerne l’étude et l’implémentation de stratégies de reconfiguration dans l’interface de communication radio, qui est souvent la principale source de consommation d’énergie d’un capteur, afin de permettre au nœud et/ou au réseau de minimiser sa consommation lorsque le bilan de liaison RF est favorable. A cette fin, nous avons proposé une approche originale grâce au développement d’un simulateur de réseau dédié, EnvAdapt (basé sur WSNet). Dans cette nouvelle plateforme, des modèles de consommation des différents blocs du transceiver radio et des algorithmes de reconfiguration ont été implémentés afin d’étudier l’impact de la reconfiguration des performances de la radio sur la qualité de service et l’autonomie d’un réseau de capteursTechnological advances achieved over the past decade in the fields of microsystems and wireless communications have enabled the development of small size and low cost sensor nodes equipped with wireless communication capabilities able to establish a wireless sensor network (WSN). Each sensor node is typically equipped with one or several sensing unit, a data processing unit, a wireless communication interface and a battery. The challenges raised by WSNs has lead to the emergence of a new research domain which focuses on the study and deployment of such a networks in order to offer the required remote monitoring and control solutions for complex and unreachable environment. WSNs have found application in a wide range of different domains, including home and structural health monitoring, military surveillance, and biomedical health monitoring. These applications usually impose stringent constraints on the WSN lifetime which is expected to last several years. To reach this objective, it is necessary to reduce the overall energy consumption of the sensor node and to find an additional source of energy as well. To address the last point, energy harvesting from the environment seems to be a an efficient approach to sustain WSNs operations. However, energy harvesting devices, which must also be small, are usually unable to ensure a continuous operation of sensor nodes. Thus, it is necessary to adapt the WSN consumption and activity to the low and unpredictable energy scavenged. The work presented in this thesis focuses on the issue of simulation and power consumption of autonomous sensor nodes. We have first developed, HarvWSNet, a co-simulation framework combining WSNet and Matlab that provides adequate tools to accurately simulate heterogenous protocols (based on discrete-time events) and energy harvesting systems (based on continuous-time events). We have demonstrated that HarvWSNet allows a rapid evaluation of energy-harvesting WSNs deployment scenarios that may accelerate the time-to-market for these systems. Thanks to the accurate energy models (battery, supercapacitor, etc.) implemented in this platform, we have studied and evaluated a large scale deployment of solar and wind energy-harvesting WSNs. Our second contribution focuses on the implementation of energy-aware reconfiguration strategies in the radio transceiver which is usually considered as the most energy hungry component in a sensor node. These strategies are intended to reduce the excessive power consumption of the radio transceiver when the channel conditions are favorable. To this end, we have a new simulation framework called EnvAdapt (based also on WSNet) dedicated to the evaluation of reconfigurable radio transceivers for WSNs. In EnvAdapt, we have implemented the required radio transceiver behavioral and power consumption models that allows the evaluation of the impact of radio transceiver reconfiguration on the communication performance and lifetime of WSNs
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Khan, Rafiullah. "Energy-aware home area networking." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/285658.
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A study by Lawrence Berkeley National Laboratory (LBNL) revealed that about 60% of the office PCs are left powered-up 24/7 only to maintain the network connectivity for remote access, Voice-over-IP (VOIP) clients, Instant Messaging (IM) and other administrative management reasons. The Advanced Configuration and Power Interface (ACPI) proposed several low power states for PCs as effective mechanism to reduce energy waste, but unfortunately they are seldomly used due to their incapability to maintain network presence. Thus, Billions of dollars of electricity is wasted every year to keep idle or unused network devices fully powered-up only to maintain the network connectivity.This dissertation addresses the Network Connectivity Proxy (NCP), a concept recently been proposed as an optimal strategy to reduce energy waste due to idle network devices. The NCP is a software entity running on a low power network device (such as home gateway, switch or router) and impersonates presence for high power devices (such as PCs) during their sleeping periods. It wakes-up a sleeping device only when its resources are required. In short, the NCP impersonates link layer, network layer, transport layer and application layer presence on behalf of sleeping devices.
In this dissertation, we presented the design and implementation of our NCP prototype. The NCP concept faces several issues and challenges that we tried to address in the most effective way in our implementations. Knowing when to start or stop proxying presence on behalf of sleeping devices is critically important for the NCP operations. To achieve this objective in a seamless way without requiring any user intervention, we developed a kernel module that monitors the power state transitions of the device and immediately informs the NCP over a suitable communication protocol in case of any update. An important challenge for the NCP is its ability to proxy a huge and ever increasing number of applications and networking protocols on behalf of sleeping devices. To tackle with this challenge in an efficient way, we implemented a quite generalized set of behavioral rules in our NCP framework that can be suitable for any protocol or application. We also incorporated deployment flexibility in our NCP software that enables us to operate it on on-board NIC, switch/router or on a standalone PC.
On-board NIC and switch/router are the optimal locations for the NCP software in home/small office environment (very limited number of devices) or a standalone PC with enough resources is a good choice if high scalability is desirable e.g., medium or large size organizations. A communication protocol is required for information exchange between the NCP and client devices e.g., for power state notifications, registration/de-registration of client devices/behavioral rules etc. To avoid any configuration issues, we developed a flexible and reliable communication framework based on the Universal Plug & Play (UPnP) architecture that provides interesting features such as auto-discovery, zero-configuration and seamless communication between the NCP and client devices.
We expanded the NCP coverage beyond LAN boundaries in order to exploit its full potential in terms of energy savings by covering for thousands of client devices. A single global powerful NCP instance located anywhere in the Internet can make easier the implementation of complex tasks and boosts up the energy savings by also shutting down the unused access links and the packets forwarding equipments whenever possible. Further, we also extended the NCP concept for mobile devices to help in improving the battery life. Another important contribution of this dissertation includes the extensive evaluation of the NCP performance on different low power hardwares. We performed large number of experiments and evaluated the effectiveness of NCP prototype in different
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Spalluto, Angelo. "Energy Aware RTOS for EFM32." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for datateknikk og informasjonsvitenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13918.
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Power consumption is a major concern for portable or battery-operated devices.Recently, new low power consumption techniques have been used to achieveacceptable autonomy battery-powered systems. FreeRTOS is a real-time kernel designedespecially for embedded low-power MCUs. Energy Micro develops and sellsenergy friendly microcontrollers based on the industry leading ARM Cortex-M332-bit architecture. The aim of this thesis is to propose a new FreeRTOS TicklessFramework solution that exploits the power modes provided by EFM32. Three differentsolutions have been proposed, such as FreeRTOS RTC, FreeRTOS Ticklesswith prescaling and FreeRTOS Tickless without prescaling. The simulations showedthat the Tickless Framework saves energy from 15x to 44x more than Original versionof FreeRTOS. Using a self-made benchmark the battery (1500 mAh) lifetimehas been increased from 11 days to 487 days.
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Barr, Kenneth C. (Kenneth Charles) 1978. "Energy aware lossless data compression." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87316.
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Balakrishnan, Manikanden, Subah Ramakrishnan, and Hong Huang. "ENERGY-AWARE SENSOR MAC PROTOCOLS." International Foundation for Telemetering, 2004. http://hdl.handle.net/10150/605793.
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International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, CaliforniaSensor network applications typically require continuous monitoring of physical phenomena for extended periods of time under severe energy resource constraints. Accordingly, design considerations for sensor Media Access Control (MAC) protocols depart significantly from those of traditional wireless MAC protocols that largely ignore the energy factor. In this paper, we reexamine the design space of wireless sensor MAC protocols and modify IEEE 802.11 Distributed Coordination Function (DCF) to incorporate energy-adaptive contention mechanisms for prolonging sensor lifetime. Performance of the proposed schemes is evaluated with DCF as a baseline and results indicate the benefits of energy-aware mechanisms for sensor MAC protocols.
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Rodriguez, Brljevich Esteban 1984. "Energy-aware virtual network mapping." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/275512.
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Orientador: Nelson Luis Saldanha da FonsecaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação
Made available in DSpace on 2018-08-25T09:43:36Z (GMT). No. of bitstreams: 1 RodriguezBrljevich_Esteban_M.pdf: 2281259 bytes, checksum: 12557ac80a34c2bff2547f1f2aff1eaa (MD5) Previous issue date: 2013
Resumo: A virtualização de redes é uma tecnologia promissora para a Internet do futuro, já que facilita a implementação de novos protocolos e aplicações sem a necessidade de alterar o núcleo da rede. Um passo chave para instanciar redes virtuais é a alocação de recursos físicos para elementos virtuais (roteadores e enlaces). A fim de contribuir para o esforço global de poupança de energia, a escolha de recursos físicos para instanciar uma rede virtual deveria minimizar o consumo de energia rede. No entanto, esta não é uma tarefa trivial, já que requerimentos de QoS devem ser atingidos. A busca da solução ótima deste problema é NP-difícil. O mapeamento de redes virtuais em substratos de rede físicos em cenários de alocaç?o e desalocaç?o de redes virtuais pode não levar a um consumo mínimo de energia devido à dinâmica das atribuições dos elementos virtuais previamente alocados. Tal dinâmica pode levar à subutilização da rede substrato. Para reduzir os efeitos negativos desta dinâmica, técnicas tais como a migração de redes virtuais em tempo real podem ser empregadas para rearranjar as redes virtuais previamente mapeadas para poupar energia. Esta dissertação apresenta um conjunto de novos algoritmos para o mapeamento de redes virtuais em substratos de rede com o objetivo de reduzir o consumo de energia. Além disso, dois novos algoritmos são propostos para a migração dos roteadores e enlaces virtuais para reduzir o número de roteadores e amplificadores ópticos requeridos. Os resultados obtidos por simulação mostram a eficácia dos algoritmos propostos
Abstract: Network virtualization is a promising technology for the Internet of the Future since it facilitates the deployment of new protocols and applications without the need of changing the core of the network. A key step to instantiate virtual networks is the allocation of physical resources to virtual elements (routers and links). In order to contribute to the global effort of saving energy, choice of physical resources to instantiate a virtual network needs to minimize the network energy consumption. However, this is not a trivial task, since the QoS of the application requirements has to be supported. Indeed, the search for the optimal solution of this problem is NP-hard. The mapping of virtual networks on network substrates at the arrival time of requests to the establishment of virtual networks may not lead to a global minimum energy consumption of energy due to the dynamic allocations and deallocations of virtual networks. Actually, such dynamics can lead to the underutilization of the network substrate. To mitigate the negative effect of this dynamics, techniques such as live migration can be employed to rearrange already mapped virtual networks to achieve energy savings. This dissertation presents a set of new algorithms for the mapping of virtual networks on network substrates aiming to reduce energy consumption. Additionally, two new algorithms are proposed for the migration of virtual routers and links to reduce the number of powered routers and optical amplifiers. Results derived by simulation show the efficacy of the proposed algorithms
Mestrado
Ciência da Computação
Mestre em Ciência da Computação
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Darby, Sarah. "Awareness, action and feedback in domestic energy use." Thesis, University of Oxford, 2003. https://ora.ox.ac.uk/objects/uuid:144896dd-f8d8-40ef-8122-5aeb3ac1551c.
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The nature of gas and electricity and the methods of distribution, billing and payment all contribute to the 'invisibility' of much domestic energy consumption in industrial and post-industrial societies. For the householder, understanding how to invest and behave in ways that will give affordable comfort with minimum environmental impact involves making sense of a hidden set of processes. This poses a major challenge, one that a range of energy advice programmes is attempting to meet. The main focus to date has been on the actions taken as a result of advice, with little attention paid to teaching and learning processes or to context. This thesis explores formal and informal processes by which householders learn about their energy use in order to develop a theoretical framework. Constructivist learning theory guides the investigation and a variant of the 'conscious competence' model of learning is used as a starting point. The concept of'tacit knowledge' (foundational knowledge, usually acquired informally) is used in tracing the development of energy literacy. Empirical data come from householder surveys and from interviews of householders and advisers in five contrasting locations in the UK. Interpretation of this material demonstrates the construction of meaning through experience and interaction with others, and the potential role of the energy adviser as a trusted and knowledgeable person. The building of tacit knowledge is crucial to the development of energy literacy and the householder's ability to absorb and evaluate new information. Energy advisers need to be able to identify and develop existing knowledge, and to form effective networks with social welfare programmes. The need to build awareness by following up advice wherever possible is stressed. There also needs to be a supportive learning infrastructure that includes easily accessible feedback on consumption, and the availability of accurate information for those who are knowledgeable and confident enough to teach themselves.
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Maler, David. "Creating Energy Awareness at Coca-Cola Enterprises Sweden." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122880.
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Alabi, Derrick. "Energy-Aware Task Scheduling in Contiki." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-348877.
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Applications for the Internet of Things often run on devices that have very limited energy capacity. Energy harvesting can offset this inherent weakness of these devices by extracting energy from the environment. Energy harvesting increases the total energy available to a device, but efficient energy consumption is still important to maximize the availability of the device. Energy-aware task scheduling is a way to efficiently consume energy in an energy constrained device with energy harvesting capabilities to extend the device's availability. In this thesis, prediction of future incoming harvest energy is combined with hard real-time and reward-based weakly-hard real-time task scheduling schemes to achieve efficient energy usage. Linear regression and artificial neural networks are evaluated individually on their ability to predict future energy harvests. The artificial neural network used contains a single hidden layer and is evaluated with ReLU, Leaky ReLU ,and sine as activation functions. The performance of linear regression and the artificial neural network with varying activation functions and number of hidden nodes are tested and compared. Linear regression is shown to be a sufficient means of predicting future energy harvests. A hard real-time and a reward-based weakly-hard real-time task scheduling scheme are also presented and compared. The experimental results show that the hard real-time scheme can extend the life of the device compared to a non-energy-aware scheduler, but the weakly-hard real-time scheme will allow the device to function indefinitely.
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Renaud-Goud, Paul. "Energy-aware scheduling : complexity and algorithms." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2012. http://tel.archives-ouvertes.fr/tel-00744247.
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In this thesis we have tackled a few scheduling problems under energy constraint, since the energy issue is becoming crucial, for both economical and environmental reasons. In the first chapter, we exhibit tight bounds on the energy metric of a classical algorithm that minimizes the makespan of independent tasks. In the second chapter, we schedule several independent but concurrent pipelined applications and address problems combining multiple criteria, which are period, latency and energy. We perform an exhaustive complexity study and describe the performance of new heuristics. In the third chapter, we study the replica placement problem in a tree network. We try to minimize the energy consumption in a dynamic frame. After a complexity study, we confirm the quality of our heuristics through a complete set of simulations. In the fourth chapter, we come back to streaming applications, but in the form of series-parallel graphs, and try to map them onto a chip multiprocessor. The design of a polynomial algorithm on a simple problem allows us to derive heuristics on the most general problem, whose NP-completeness has been proven. In the fifth chapter, we study energy bounds of different routing policies in chip multiprocessors, compared to the classical XY routing, and develop new routing heuristics. In the last chapter, we compare the performance of different algorithms of the literature that tackle the problem of mapping DAG applications to minimize the energy consumption.
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Liu, Chang. "Energy Aware Management of 5G Networks." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32492.
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Doctor of PhilosophyDepartment of Electrical and Computer Engineering
Balasubramaniam Natarajan
The number of wireless devices is predicted to skyrocket from about 5 billion in 2015 to 25 billion by 2020. Therefore, traffic volume demand is envisioned to explode in the very near future. The proposed fifth generation (5G) of mobile networks is expected to be a mixture of network components with different sizes, transmit powers, back-haul connections and radio access technologies. While there are many interesting problems within the 5G framework, we address the challenges of energy-related management in a heterogeneous 5G networks. Based on the 5G architecture, in this dissertation, we present some fundamental methodologies to analyze and improve the energy efficiency of 5G network components using mathematical tools from optimization, control theory and stochastic geometry. Specifically, the main contributions of this research include: • We design power-saving modes in small cells to maximize energy efficiency. We first derive performance metrics for heterogeneous cellular networks with sleep modes based on stochastic geometry. Then we quantify the energy efficiency and maximize it with quality-of-service constraint based on an analytical model. We also develop a simple sleep strategy to further improve the energy efficiency according to traffic conditions. • We conduct a techno-economic analysis of heterogeneous cellular networks powered by both on-grid electricity and renewable energy. We propose a scheme to minimize the electricity cost based on a real-time pricing model. • We provide a framework to uncover desirable system design parameters that offer the best gains in terms of ergodic capacity and average achievable throughput for device-to-device underlay cellular networks. We also suggest a two-phase scheme to optimize the ergodic capacity while minimizing the total power consumption. • We investigate the modeling and analysis of simultaneous information and energy transfer in Internet of things and evaluate both transmission outage probability and power outage probability. Then we try to balance the trade-off between the outage performances by careful design of the power splitting ratio. This research provides valuable insights related to the trade-offs between energy-conservation and system performance in 5G networks. Theoretical and simulation results help verify the performance of the proposed algorithms.
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Rossi, F?bio Diniz. "Performance-Aware Energy-Efficient Cloud Orchestration." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2016. http://tede2.pucrs.br/tede2/handle/tede/7039.
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O alto consumo de energia dos centros de dados tem sido foco na maioria das pesquisas recentes. Em ambientes de nuvem, v?rias solu??es est?o sendo propostas com o objetivo de alcan?ar efici?ncia energ?tica, que v?o desde o dimensionamento da frequ?ncia de processadores, da utiliza??o de estados suspens?o, at? a consolida??o de servidores virtuais. Embora estas solu??es permitam redu??o no consumo de energia, apresentam impacto sobre o desempenho das aplica??es. Visando resolver esta limita??o, n?s apresentamos uma orquestra??o de diferentes t?cnicas e mecanismos de economia de energia, com a finalidade de melhorar o balanceamento entre economia de energia e desempenho das aplica??es. Para este fim, implementamos o e-eco, um sistema de gest?o que atua juntamente com a plataforma de nuvem, decidindo qual estado de suspens?o pode ser melhor aplicado sobre os servidores, al?m de escolher a melhor op??o entre consolida??o de servidores ou dimensionamento de frequ?ncia dos processadores. Para avaliar o e-eco, testes foram realizados em ambientes de nuvem real e simulado, utilizando aplica??es scale-out em uma infraestrutura de nuvem din?mica, levando em considera??o transa??es-por-segundo como m?trica de desempenho. Os resultados mostraram que nossa proposta apresenta a melhor rela??o entre economia de energia e desempenho de aplica??es em ambientes de nuvem, quando comparada com outros trabalhos apresentados na literatura.
The high energy consumption of data centers has been a recurring issue in recent research. In cloud environments, several solutions are being used that aim for energy efficiency, ranging from scaling the processors frequency, through the use of sleep states, to virtual machine placement mechanism. Although these solutions enable the reduction in power consumption, they usually impact on the application performance. To address this limitation, we present an orchestration of different energy-savings techniques and mechanisms to improve the trade-off between energy savings and application performance. To this end, we implemented the Energy-Efficient Cloud Orchestrator ? e-eco ? a management system that acts along with the cloud platform, deciding which sleep state can be better applied on hosts, in addition to choosing the best option between virtual machines consolidation and dynamic processor frequency scaling. To evaluate e-eco, tests were carried out in a real and a simulated environment using scale-out applications on a dynamic cloud infrastructure, taking into account transactions per second as a performance metric. Results showed that our proposal presents the best improvement on the trade-off between energy savings and performance applications for cloud environments when compared with other works presented in the literature.
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Doddapaneni, Krishna. "Energy aware performance evaluation of WSNs." Thesis, Middlesex University, 2014. http://eprints.mdx.ac.uk/17460/.
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Distributed sensor networks have been discussed for more than 30 years, but the vision of Wireless Sensor Networks (WSNs) has been brought into reality only by the rapid advancements in the areas of sensor design, information technologies, and wireless networks that have paved the way for the proliferation of WSNs. The unique characteristics of sensor networks introduce new challenges, amongst which prolonging the sensor lifetime is the most important. Energy-efficient solutions are required for each aspect of WSN design to deliver the potential advantages of the WSN phenomenon, hence in both existing and future solutions for WSNs, energy efficiency is a grand challenge. The main contribution of this thesis is to present an approach considering the collaborative nature of WSNs and its correlation characteristics, providing a tool which considers issues from physical to application layer together as entities to enable the framework which facilitates the performance evaluation of WSNs. The simulation approach considered provides a clear separation of concerns amongst software architecture of the applications, the hardware configuration and the WSN deployment unlike the existing tools for evaluation. The reuse of models across projects and organizations is also promoted while realistic WSN lifetime estimations and performance evaluations are possible in attempts of improving performance and maximizing the lifetime of the network. In this study, simulations are carried out with careful assumptions for various layers taking into account the real time characteristics of WSN. The sensitivity of WSN systems are mainly due to their fragile nature when energy consumption is considered. The case studies presented demonstrate the importance of various parameters considered in this study. Simulation-based studies are presented, taking into account the realistic settings from each layer of the protocol stack. Physical environment is considered as well. The performance of the layered protocol stack in realistic settings reveals several important interactions between different layers. These interactions are especially important for the design of WSNs in terms of maximizing the lifetime of the network.
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Mahadevamangalam, Srivasthav. "Energy-aware adaptation in Cloud datacenters." Thesis, Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-17373.
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Context: Cloud computing is providing services and resources to customers based on pay-per-use. As the services increasing, Cloud computing using a vast number of data centers like thousands of data centers which consumes high energy. The power consumption for cooling the data centers is very high. So, recent research going on to implement the best model to reduce the energy consumption by the data centers. This process of minimizing the energy consumption can be done using dynamic Virtual Machine Consolidation (VM Consolidation) in which there will be a migration of VMs from one host to another host so that energy can be saved. 70% of energy consumption will be reduced/ saved when the host idle mode is switched to sleep mode, and this is done by migration of VM from one host to another host. There are many energy adaptive heuristics algorithms for the VM Consolidation. Host overload detection, host underload detection and VM selection using VM placement are the heuristics algorithms of VM Consolidation which results in less consumption of the energy in the data centers while meeting Quality of Service (QoS). In this thesis, we proposed new heuristic algorithms to reduce energy consumption. Objectives: The objective of this research is to provide an energy efficient model to reduce energy consumption. And proposing a new heuristics algorithms of VM Consolidationtechnique in such a way that it consumes less energy. Presenting the advantages and disadvantages of the proposed heuristics algorithms is also considered as objectives of our experiment. Methods: Literature review was performed to gain knowledge about the working and performances of existing algorithms using VM Consolidation technique. Later, we have proposed a new host overload detection, host underload detection, VM selection, and VM placement heuristic algorithms. In our work, we got 32 combinations from the host overload detection and VM selection, and two VM placement heuristic algorithms. We proposed dynamic host underload detection algorithm which is used for all the 32 combinations. The other research method chosen is experimentation, to analyze the performances of both proposed and existing algorithms using workload traces of PlanetLab. This simulation is done usingCloudSim. Results: To compare and get the results, the following parameters had been considered: Energy consumption, No. of migrations, Performance Degradation due to VM Migrations (PDM),Service Level Agreement violation Time per Active Host (SLATAH), SLA Violation (SLAV),i.e. from a combination of the PDM, SLATAH, Energy consumption and SLA Violation (ESV).We have conducted T-test and Cohen’s d effect size to measure the significant difference and effect size between algorithms respectively. For analyzing the performance, the results obtained from proposed algorithms and existing algorithm were compared. From the 32 combinations of the host overload detection and VM Selection heuristic algorithms, MADmedian_MaxR (Mean Absolute Deviation around median (MADmedian) and Maximum Requested RAM (MaxR))using Modified Worst Fit Decreasing (MWFD) VM Placement algorithm, andMADmean_MaxR (Mean Absolute Deviation around mean (MADmean), and MaximumRequested RAM (MaxR)) using Modified Second Worst Fit Decreasing (MSWFD) VM placement algorithm respectively gives the best results which consume less energy and with minimum SLA Violation. Conclusion: By analyzing the comparisons, it is concluded that proposed algorithms perform better than the existing algorithm. As our aim is to propose the better energy- efficient model using the VM Consolidation techniques to minimize the power consumption while meeting the SLAs. Hence, we proposed the energy- efficient algorithms for VM Consolidation technique and compared with the existing algorithm and proved that our proposed algorithm performs better than the other algorithm. We proposed 32 combinations of heuristics algorithms (host overload detection and VM selection) with two adaptive heuristic VM placement algorithms. We have proposed a dynamic host underload detection algorithm, and it is used for all 32 combinations. When the proposed algorithms are compared with the existing algorithm, we got 22 combinations of host overload detection and VM Selection heuristic algorithms with MWFD(Modified Worst Fit Decreasing) VM placement and 20 combinations of host overload detection and VM Selection heuristic algorithms with MSWFD (Modified Second Worst FitDecreasing) VM placement algorithm which shows the better performance than existing algorithm. Thus, our proposed heuristic algorithms give better results with minimum energy consumption with less SLA violation.
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Pyles, andrew Joseph. "Network Traffic Aware Smartphone Energy Savings." W&M ScholarWorks, 2013. https://scholarworks.wm.edu/etd/1539623617.
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In today's world of ubiquitous Smartphone use, extending the battery life has become an important issue. A significant contributor to battery drain is wireless networking. Common usage patterns expect Smartphones to maintain a constant Internet connection which exacerbates the problem.;Our research entitled A Network Traffic Approach to Smartphone Energy Savings focuses on extending Smartphone battery life by investigating how network traffic impacts power management of wireless devices. We explore 1) Real-time VoIP application energy savings by exploiting silence periods in conversation. WiFi is opportunistically placed into low power mode during Silence periods. 2.) The priority of Smartphone Application network traffic is used to modifiy WiFi radio power management using machine learning assisted prioritization. High priority network traffic is optimized for performance, consuming more energy while low priority network traffic is optimized for energy conservation. 3.) A hybrid multiple PHY, MAC layer approach to saving energy is also utilized. The Bluetooth assisted WiFi approach saves energy by combining high power, high throughput WiFi with low power, lower throughput Bluetooth. The switch between Bluetooth and WiFi is done opportunistically based upon the current data rate and health of the Bluetooth connection.;Our results show that application specific methods for wireless energy savings are very effective. We have demonstrated energy savings exceeding 50% in generic cases. With real-time VoIP applications we have shown upwards of 40% energy savings while maintaining good call quality. The hybrid multiple PHY approach saves more than 25% energy over existing solutions while attaining the capability of quickly adapting to changes in network traffic.
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Yu, Yi. "Enabling energy awareness of ICT users to improve energy efficiency during use of systems." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7037.
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Data centres have been the primary focus of energy efficiency researches due to their expanding scales and increasing demands of energy. On the other hand, there are several orders of magnitude more end-users and personal computing devices worldwide. Even the modest energy savings from the users would scale up and yield significant impact. As a result, we take the approach towards energy-saving by working with the end-users. We recognise that users of ICT systems are often unaware of their power usage, and are therefore unable to take effective actions even if they wanted to save energy. Apart from energy awareness, the majority of end-users often lack of sufficient knowledge or skills to reduce their energy consumption while using computing devices. Moreover, there is no incentive for them to save energy, especially in public environments where they do not have financial responsibilities for their energy use. We propose a flexible energy monitor that gathers detailed energy usage across complex ICT systems, and provides end-users with accurate and timely feedback of their individual energy usage per workstation. We tailored our prototype energy monitor for a 2-year empirical study, with 83 student users of a university computer lab, and showed that end-users will change their use of computers to be more energy efficient, when sufficient feedback and incentives (rewards) are provided. In our measurements, weekly mean group power consumption as a whole reduced by up to 16%; and weekly individual user power usage reduced by up to 56% during active use. Based on our observations and collected data, we see possibilities of energy saving from both hardware and software components of personal computers. It requires coordination and collaboration between both system administrators and end-users to maximise energy savings. Institutional ‘green' policies are potentially helpful to enforce and regulate energy efficient use of ICT devices.
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Kissinger, Thomas. "Energy-Aware Data Management on NUMA Architectures." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-223436.
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The ever-increasing need for more computing and data processing power demands for a continuous and rapid growth of power-hungry data center capacities all over the world. As a first study in 2008 revealed, energy consumption of such data centers is becoming a critical problem, since their power consumption is about to double every 5 years. However, a recently (2016) released follow-up study points out that this threatening trend was dramatically throttled within the past years, due to the increased energy efficiency actions taken by data center operators. Furthermore, the authors of the study emphasize that making and keeping data centers energy-efficient is a continuous task, because more and more computing power is demanded from the same or an even lower energy budget, and that this threatening energy consumption trend will resume as soon as energy efficiency research efforts and its market adoption are reduced. An important class of applications running in data centers are data management systems, which are a fundamental component of nearly every application stack. While those systems were traditionally designed as disk-based databases that are optimized for keeping disk accesses as low a possible, modern state-of-the-art database systems are main memory-centric and store the entire data pool in the main memory, which replaces the disk as main bottleneck. To scale up such in-memory database systems, non-uniform memory access (NUMA) hardware architectures are employed that face a decreased bandwidth and an increased latency when accessing remote memory compared to the local memory.
In this thesis, we investigate energy awareness aspects of large scale-up NUMA systems in the context of in-memory data management systems. To do so, we pick up the idea of a fine-grained data-oriented architecture and improve the concept in a way that it keeps pace with increased absolute performance numbers of a pure in-memory DBMS and scales up on NUMA systems in the large scale. To achieve this goal, we design and build ERIS, the first scale-up in-memory data management system that is designed from scratch to implement a data-oriented architecture. With the help of the ERIS platform, we explore our novel core concept for energy awareness, which is Energy Awareness by Adaptivity. The concept describes that software and especially database systems have to quickly respond to environmental changes (i.e., workload changes) by adapting themselves to enter a state of low energy consumption. We present the hierarchically organized Energy-Control Loop (ECL), which is a reactive control loop and provides two concrete implementations of our Energy Awareness by Adaptivity concept, namely the hardware-centric Resource Adaptivity and the software-centric Storage Adaptivity. Finally, we will give an exhaustive evaluation regarding the scalability of ERIS as well as our adaptivity facilities.
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Padoin, Edson Luiz. "Energy-aware load balancing approaches to improve energy efficiency on HPC systems." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/140401.
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Os atuais sistemas de HPC tem realizado simulações mais complexas possíveis, produzindo benefícios para diversas áreas de pesquisa. Para atender à crescente demanda de processamento dessas simulações, novos equipamentos estão sendo projetados, visando à escala exaflops. Um grande desafio para a construção destes sistemas é a potência que eles vão demandar, onde perspectivas atuais alcançam GigaWatts. Para resolver este problema, esta tese apresenta uma abordagem para aumentar a eficiência energética usando recursos de HPC, objetivando reduzir os efeitos do desequilíbrio de carga e economizar energia. Nós desenvolvemos uma estratégia baseada no consumo de energia, chamada ENERGYLB, que considera características da plataforma, irregularidade e dinamicidade de carga das aplicações para melhorar a eficiência energética. Nossa estratégia leva em conta carga computacional atual e a frequência de clock dos cores, para decidir entre chamar uma estratégia de balanceamento de carga que reduz o desequilíbrio de carga migrando tarefas, ou usar técnicas de DVFS par ajustar as frequências de clock dos cores de acordo com suas cargas computacionais ponderadas. Como as diferentes arquiteturas de processador podem apresentam dois níveis de granularidade de DVFS, DVFS-por-chip ou DVFS-por-core, nós criamos dois diferentes algoritmos para a nossa estratégia. O primeiro, FG-ENERGYLB, permite um controle fino da frequência dos cores em sistemas que possuem algumas dezenas de cores e implementam DVFS-por-core. Por outro lado, CG-ENERGYLB é adequado para plataformas de HPC composto de vários processadores multicore que não permitem tal refinado controle, ou seja, que só executam DVFS-por-chip. Ambas as abordagens exploram desbalanceamentos residuais em aplicações interativas e combinam balanceamento de carga dinâmico com técnicas de DVFS. Assim, eles reduzem a frequência de clock dos cores com menor carga computacional os quais apresentam algum desequilíbrio residual mesmo após as tarefas serem remapeadas. Nós avaliamos a aplicabilidade das nossas abordagens utilizando o ambiente de programação paralela CHARM++ sobre benchmarks e aplicações reais. Resultados experimentais presentaram melhorias no consumo de energia e na demanda potência sobre algoritmos do estado-da-arte. A economia de energia com ENERGYLB usado sozinho foi de até 25% com nosso algoritmo FG-ENERGYLB, e de até 27% com nosso algoritmo CG-ENERGYLB. No entanto, os desequilíbrios residuais ainda estavam presentes após as serem tarefas remapeadas. Neste caso, quando as nossas abordagens foram empregadas em conjunto com outros balanceadores de carga, uma melhoria na economia de energia de até 56% é obtida com FG-ENERGYLB e de até 36% com CG-ENERGYLB. Estas economias foram obtidas através da exploração do desbalanceamento residual em aplicações interativas. Combinando balanceamento de carga dinâmico com DVFS nossa estratégia é capaz de reduzir a demanda de potência média dos sistemas paralelos, reduzir a migração de tarefas entre os recursos disponíveis, e manter o custo de balanceamento de carga baixo.Current HPC systems have made more complex simulations feasible, yielding benefits to several research areas. To meet the increasing processing demands of these simulations, new equipment is being designed, aiming at the exaflops scale. A major challenge for building these systems is the power that they will require, which current perspectives reach the GigaWatts. To address this problem, this thesis presents an approach to increase the energy efficiency using of HPC resources, aiming to reduce the effects of load imbalance to save energy. We developed an energy-aware strategy, called ENERGYLB, which considers platform characteristics, and the load irregularity and dynamicity of the applications to improve the energy efficiency. Our strategy takes into account the current computational load and clock frequency, to decide whether to call a load balancing strategy that reduces load imbalance by migrating tasks, or use Dynamic Voltage and Frequency Scaling (DVFS) technique to adjust the clock frequencies of the cores according to their weighted loads. As different processor architectures can feature two levels of DVFS granularity, per-chip DVFS or per-core DVFS, we created two different algorithms for our strategy. The first one, FG-ENERGYLB, allows a fine control of the clock frequency of cores in systems that have few tens of cores and feature per-core DVFS control. On the other hand, CGENERGYLB is suitable for HPC platforms composed of several multicore processors that do not allow such a fine-grained control, i.e., that only perform per-chip DVFS. Both approaches exploit residual imbalances on iterative applications and combine dynamic load balancing with DVFS techniques. Thus, they reduce the clock frequency of underloaded computing cores, which experience some residual imbalance even after tasks are remapped. We evaluate the applicability of our approaches using the CHARM++ parallel programming system over benchmarks and real world applications. Experimental results present improvements in energy consumption and power demand over state-of-the-art algorithms. The energy savings with ENERGYLB used alone were up to 25%with our FG-ENERGYLB algorithm, and up to 27%with our CG-ENERGYLB algorithm. Nevertheless, residual imbalances were still present after tasks were remapped. In this case, when our approaches were employed together with these load balancers, an improvement in energy savings of up to 56% is achieved with FG-ENERGYLB and up to 36% with CG-ENERGYLB. These savings were obtained by exploiting residual imbalances on iterative applications. By combining dynamic load balancing with the DVFS technique, our approach is able to reduce the average power demand of parallel systems, reduce the task migration among the available resources, and keep load balancing overheads low.
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Dolz, Zaragozá Manuel Francisco. "Energy-aware matrix computacion on multirhreaded architectures." Doctoral thesis, Universitat Jaume I, 2014. http://hdl.handle.net/10803/669082.
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Desde hace décadas, la computación de altas prestaciones ha concentrado sus esfuerzos en la optimización de algoritmos aplicados a la resolución de problemas complejos que aparecen en un amplio abanico de aplicaciones de casi todas las áreas científicas y tecnológicas. En este sentido el uso de herramientas y técnicas, tales como la computación paralela y distribuida, han impulsado la mejora de las prestaciones en este tipo de algoritmos y aplicaciones. Hoy en día, el término optimización hace referencia a la reducción del tiempo de ejecución, aunque también a la energía necesaria para su cómputo.
La búsqueda de soluciones verdes o fuentes de energía alternativas que permitan reducir las emisiones de CO2 a la atmósfera demuestran la creciente preocupación por el medio ambiente. En el ámbito de las tecnologías de la información y, más concretamente, en la computación de altas prestaciones, la comunidad científico-técnica muestra especial interés en el desarrollo de componentes, herramientas y técnicas que permitan minimizar el consumo energético. En este sentido, se pretende que las aplicaciones sean conscientes de la energía disipada, tanto en el sistema operativo como en las bibliotecas de cómputo, comunicación y aplicaciones paralelas.
Los objetivos de la presente tesis están orientados al estudio, análisis y aprovechamiento de las técnicas de ahorro disponibles en las arquitecturas de computadores multinúcleo e híbridas (CPU-GPU) actuales actuales con el fin de mejorar el rendimiento energético en aplicaciones que requieren la resolución de problemas de
álgebra lineal densa y dispersa. Los resultados experimentales obtenidos que validan las ganancias conseguidas mediante medidores de energía, consiguiendo destacables ahorros energéticos y manteniendo un constante compromiso entre prestaciones y ahorros generados.
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Klaiqi, Bleron. "Energy-efficient and overhead-aware cooperative communications." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/18231/.
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Due to the rapid growth of energy-hungry wireless multimedia services, telecom energy consumption is increasing at an extraordinary rate. Besides negative environmental impacts and higher energy bills for operators, it also affects user experience as improvements in battery technologies have not kept up with increasing mobile energy demands. Therefore, how to increase the energy efficiency (EE) of wireless communications has gained a lot of attention recently. Cooperative communication, where relays cooperatively retransmit the received data from the source to the destination, is seen as a promising technique to increases EE. Nevertheless, it requires more overhead than direct communication that needs to be taken into account for practical wireless cooperative networks. In order to achieve potential energy savings promised by cooperative communications in practical systems, overhead-aware cooperative relaying schemes with low overhead are imperative. For the case that not all relays can hear each other, i.e., hidden relays exist, an energy-efficient and a low-overhead cooperative relaying scheme is proposed. This scheme selects a subset of relays before data transmission, through the proactive participation of available relays using their local timers. Theoretical analysis of average EE under maximum transmission power constraint, using practical data packet length, and taking account of the overhead for obtaining channel state information (CSI), relay selection, and cooperative beamforming, is performed and a closed-form approximate expression for the optimal position of relays is derived. Furthermore, the overhead of the proposed scheme and the impact of data packet lengths on EE, are analysed. The analytical and simulation results reveal that the proposed scheme is significantly more energy-efficient than direct transmission, best relay selection, all relay selection, and a state-of-the-art existing cooperative relaying scheme. Moreover, the proposed scheme reduces the overhead and achieves higher energy savings for larger data packets. The conventional cooperative beamforming schemes rely on the feedback of CSIs of the best relays from the destination, which cause extra energy consumption and are prone to quantization errors in practical systems. In the case of clustered relays with location awareness and timer-based relay selection, where relays can overhear the transmission and know the location of each other, an energy-efficient overhead-aware cooperative relaying scheme is proposed, making CSI feedback from the destination dispensable. In order to avoid possible collisions between relay transmissions during best relays selection, a distributed mechanism for the selected relays to appropriately insert guard intervals before their transmissions is proposed. Average EE of the proposed scheme considering the related overhead is analysed. Moreover, the impact of the number of available relays, the number of selected relays and the location of relay cluster on EE is studied. The simulation results indicate that the proposed cooperative relaying scheme achieves higher EE than direct communication, best relay selection, and all relay selection for relay clusters located close to the source. Independent of the relay cluster location, the proposed scheme exhibits significantly higher EE than an existing cooperative relaying scheme. Device-to-device (D2D) communication in cellular networks that enable direct transmissions between user equipments (UEs) is seen as a promising way to improve both EE and spectral efficiency (SE). If the source UE (SUE) and the destination UE (DUE) are far away from each other or if the channel between them is too weak for direct transmission, then two-hop D2D communications, where relay UEs (RUEs) forward the SUE's data packets to the DUE, can be used. An energy- and spectral-efficient optimal adaptive forwarding strategy (OAFS) for two-hop D2D communications is proposed. In a distributed manner, the OAFS adaptively chooses between the best relay forwarding (BRF) and the cooperative relay beamforming (CRB) with the optimal number of selected RUEs, depending on which of them provides the higher instantaneous EE. In order to reduce the computational complexity of relay selection, a low-complexity sub-optimal adaptive forwarding strategy (SAFS) is proposed that selects between the BRF and the CRB with two RUEs by comparing their instantaneous EE. Theoretical analysis of the average EE and SE for the proposed adaptive forwarding strategies is performed considering maximum transmission power constraints, circuit power consumption and the overhead for the acquisition of CSI, forwarding mode selection and cooperative beamforming. The theoretical and simulation results show that the proposed OAFS and SAFS exhibit significantly higher EE and SE than the BRF, CRB, direct D2D communications and conventional cellular communications. For short to moderate SUE-to-DUE distances, SAFS is almost as energy- and spectral-efficient as OAFS.
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Shi, Xiaomeng Ph D. Massachusetts Institute of Technology. "Energy aware network coding in wireless networks." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78533.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 97-104).
Energy is one of the most important considerations in designing reliable low-power wireless communication networks. We focus on the problem of energy aware network coding. In particular, we investigate practical energy efficient network code design for wireless body area networks (WBAN). We first consider converge-cast in a star-shaped topology, in which a central base station (BS), or hub, manages and communicates directly with a set of nodes. We then consider a wireless-relay channel, in which a relay node assists in the transmission of data from a source to a destination. This wireless relay channel can be seen as a simplified extended star network, where nodes have relay capabilities. The objective is to investigate the use of network coding in these scenarios, with the goal of achieving reliability under low-energy and lower-power constraints. More specifically, in a star network, we propose a simple network layer protocol, study the mean energy to complete uploads of given packets from the nodes to the BS using a Markov chain model, and show through numerical examples that when reception energy is taken into account, the incorporation of network coding offers reductions in energy use. The amount of achievable gains depends on the number of nodes in the network, the degree of asymmetry in channel conditions experienced by different nodes, and the relative difference between transmitting and receiving power at the nodes. We also demonstrate the compatibility of the proposed scheme with the IEEE 802.15.6 WBAN standard by describing ways of incorporating network coding into systems compliant to the standard. For a wireless relay channel, we explore the strategic use of network coding according to both throughput and energy metrics. In the relay channel, a single source communicates to a single sink through the aid of a half-duplex relay. The fluid flow model is used to describe the case where both the source and the relay are coding, and Markov chain models are proposed to describe packet evolution if only the source or only the relay is coding. Although we do not attempt to explicitly categorize the optimal network coding strategies in the relay channel under different system parameters, we provide a framework for deciding whether and where to code, taking into account of throughput maximization and energy depletion constraints.
by Xiaomeng Shi.
Ph.D.
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Behzadnia, Peyman. "Dynamic Energy-Aware Database Storage and Operations." Scholar Commons, 2018. http://scholarcommons.usf.edu/etd/7125.
Full textAbstract:
Energy consumption has become a first-class optimization goal in design and implementation of data-intensive computing systems. This is particularly true in the design of database management systems (DBMS), which is one of the most important servers in software stack of modern data centers. Data storage system is one of the essential components of database and has been under many research efforts aiming at reducing its energy consumption. In previous work, dynamic power management (DPM) techniques that make real-time decisions to transition the disks to low-power modes are normally used to save energy in storage systems. In this research, we tackle the limitations of DPM proposals in previous contributions and design a dynamic energy-aware disk storage system in database servers. We introduce a DPM optimization model integrated with model predictive control (MPC) strategy to minimize power consumption of the disk-based storage system while satisfying given performance requirements. It dynamically determines the state of disks and plans for inter-disk data fragment migration to achieve desirable balance between power consumption and query response time. Furthermore, via analyzing our optimization model to identify structural properties of optimal solutions, a fast-solution heuristic DPM algorithm is proposed that can be integrated in large-scale disk storage systems, where finding the most optimal solution might be long, to achieve near-optimal power saving solution within short periods of computational time. The proposed ideas are evaluated through running simulations using extensive set of synthetic workloads. The results show that our solution achieves up to 1.65 times more energy saving while providing up to 1.67 times shorter response time compared to the best existing algorithm in literature.
Stream join is a dynamic and expensive database operation that performs join operation in real-time fashion on continuous data streams. Stream joins, also known as window joins, impose high computational time and potentially higher energy consumption compared to other database operations, and thus we also tackle energy-efficiency of stream join processing in this research. Given that there is a strong linear correlation between energy-efficiency and performance of in-memory parallel join algorithms in database servers, we study parallelization of stream join algorithms on multicore processors to achieve energy efficiency and high performance. Equi-join is the most frequent type of join in query workloads and symmetric hash join (SHJ) algorithm is the most effective algorithm to evaluate equi-joins in data streams. To best of our knowledge, we are the first to propose a shared-memory parallel symmetric hash join algorithm on multi-core CPUs. Furthermore, we introduce a novel parallel hash-based stream join algorithm called chunk-based pairing hash join that aims at elevating data throughput and scalability. We also tackle parallel processing of multi-way stream joins where there are more than two input data streams involved in the join operation. To best of our knowledge, we are also the first to propose an in-memory parallel multi-way hash-based stream join on multicore processors. Experimental evaluation on our proposed parallel algorithms demonstrates high throughput, significant scalability, and low latency while reducing the energy consumption. Our parallel symmetric hash join and chunk-based pairing hash join achieve up to 11 times and 12.5 times more throughput, respectively, compared to that of state-of-the-art parallel stream join algorithm. Also, these two algorithms provide up to around 22 times and 24.5 times more throughput, respectively, compared to that of non-parallel (sequential) stream join computation where there is one processing thread.
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Toussi, Ahora Mehdi. "Energy and QoS aware routing for WSNs." Thesis, Kingston University, 2017. http://eprints.kingston.ac.uk/41130/.
Full textAbstract:
The advancement of Wireless Sensor Networks (WSNs), necessitate optimisation of their algorithms and their performance. More specifically, network coverage and preservation of nodes energy to increase the network's lifetime are among the core objectives of routing and clustering methods. This thesis constitutes of a literature review of WSNs' routing protocols in a categorised manner followed by proposing an energy efficient and QoS aware paradigm (PUSH) for flat network that outperform other similar paradigms in terms of collective delay and energy dissipation within the network. We have proposed a new clustering model, known as Energy Aware and Address Free Clustering (EAAFC) in which, no global addressing is required. In other words, nodes are assigned with an ID, based on local information. EAAFC clusters nodes with minimum number of cluster heads which in turn results in less in network energy consumption. Cluster heads are then re-elected frequently based on nodes' energy and distribution. EAAFC does not require geographical location of nodes nor time synchronisation. We compare performance results of our proposed clustering model, against two of well received algorithms, namely LEACH and EECF to demonstrate the advantages of EAAFC. In chapters 1 and 2, the major routing protocols have been studied over the years of research and strength and weaknesses of each protocol has been scrutinised. Further, objectives, motivation and methodology of the research are discussed. In chapter 3 and 4 the proposed routing paradigm for flat networks (PUSH) as well as the clustering protocol, EAAFC, and its advantages over other protocols is discussed in depth. Several scenarios based on similar well-known routing protocols have been implemented and tested to use as comparison and to evaluate the performance of paradigm and protocol presented in this thesis. These scenarios have been implemented in the simulator environment. The simulation results confirm the theoretic evaluation and support that PUSH and EAAFC outperforms the other protocols in compared criteria as they can achieve less latency, better coverage, preserve more energy and achieve more equally distributed energy dissipation across the network which result in longer network life time and full functionality.
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Tachtatzis, Christos. "Load distribution and energy awareness in manets using multipath routing." Thesis, University of Strathclyde, 2008. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21972.
Full textAbstract:
Wireless ad-hoc networks are characterised by lack of infrastructure and frequent topological changes. Traditional routing protocols seek only single paths to the desired destinations, while multipath routing obtains multiple paths for only marginal additional overhead. This work argues that multipath routing is advantageous, even allowing for the additional overheads, because of the improved network load distribution. The merits of multipath routing are shown through extensive performance evaluation considering packet delivery ratio, average end-to-end delay and routing efficiency, for both mobile and static scenarios. The second aspect of the thesis addresses energy awareness. When a single connection is considered, multipath routing can potentially consume more total energy compared to its unipath counterparts because some traffic can traverse longer (in terms of hop count) paths. On the other hand, unipath routing concentrates nodal traffic over the same single path; resulting in unfairness for the intermediate hops and uneven energy consumption which, in turn, can result in network partitioning. Here, it is argued that multipath routing extends the network lifetime, because the routing protocol can make more sophisticated decisions to avoid node exhaustion. Two novel energy aware routing schemes, which select optimal paths to homogenise the energy map of the network, are presented. A range of performance evaluation techniques are employed to demonstrate the merits of the proposed schemes, and it is shown that the approach of homogenising the network energy map mitigates against the effects of inevitable node outages cause by energy exhaustion and prolongs network lifetime.
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Hutchinson, Harriet. "Location awareness in multi-agent control of distributed energy resources." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12291/.
Full textAbstract:
The integration of Distributed Energy Resource (DER) technologies such as heat pumps, electric vehicles and small-scale generation into the electricity grid at the household level is limited by technical constraints. This work argues that location is an important aspect for the control and integration of DER and that network topology can inferred without the use of a centralised network model. It addresses DER integration challenges by presenting a novel approach that uses a decentralised multi-agent system where equipment controllers learn and use their location within the low-voltage section of the power system. Models of electrical networks exhibiting technical constraints were developed. Through theoretical analysis and real network data collection, various sources of location data were identified and new geographical and electrical techniques were developed for deriving network topology using Global Positioning System (GPS) and 24-hour voltage logs. The multi-agent system paradigm and societal structures were examined as an approach to a multi-stakeholder domain and congregations were used as an aid to decentralisation in a non-hierarchical, non-market-based approach. Through formal description of the agent attitude INTEND2, the novel technique of Intention Transfer was applied to an agent congregation to provide an opt-in, collaborative system. Test facilities for multi-agent systems were developed and culminated in a new embedded controller test platform that integrated a real-time dynamic electrical network simulator to provide a full-feedback system integrated with control hardware. Finally, a multi-agent control system was developed and implemented that used location data in providing demand-side response to a voltage excursion, with the goals of improving power quality, reducing generator disconnections, and deferring network reinforcement. The resulting communicating and self-organising energy agent community, as demonstrated on a unique hardware-in-the-loop platform, provides an application model and test facility to inspire agent-based, location-aware smart grid applications across the power systems domain.
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Broms, Loove. "Sustainable Interactions : Studies in the Design of Energy Awareness Artefacts." Licentiate thesis, Linköpings universitet, MDALAB - Human Computer Interfaces, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-67187.
Full textAbstract:
This thesis presents a collection of experimental designs that approach the problem of growing electricity consumption in homes. From the perspective of design, the intention has been to critically explore the design space of energy awareness artefacts to reinstate awareness of energy use in everyday practice. The design experiments were used as vehicles for thinking about the relationship between physical form, interaction, and social practice. The rationale behind the concepts was based on a small-scale ethnography, situated interviews, and design experience. Moreover, the thesis compares designer intention and actual user experiences of a prototype that was installed in nine homes in a residential area in Stockholm for three months. This was done in order to elicit tacit knowledge about how the concept was used in real-world domestic settings, to challenge everyday routines, and to enable both users and designers to critically reflect on artefacts and practices. From a design perspective, contributions include design approaches to communicating energy use: visualizations for showing relationships between behaviour and electricity consumption, shapes and forms to direct action, means for turning restrictions caused by energy conservation into central parts of the product experience, and ways to promote sustainable behaviour with positive driving forces based on user lifestyles. The general results indicate that inclusion is of great importance when designing energy awareness artefacts; all members of the household should be able to access, interact with, and reflect on their energy use. Therefore, design-related aspects such as placement and visibility, as well as how the artefact might affect the social interactions in the home, become central. Additionally, the thesis argues that these types of artefacts can potentially create awareness accompanied by negative results such as stress. A challenge for the designer is to create artefacts that communicate and direct energy use in ways that are attractive and can be accepted by all household members as a possible way of life.In the electronic version of the thesis the references in some of the chapters has been corrected.
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Felix, Moreno R. "Situational awareness-based energy management for unmanned electric surveillance platforms." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/10673.
Full textAbstract:
In the present day fossil fuel availability, cost, security and the pollutant emissions resulting from its use have driven industry into looking for alternative ways of powering vehicles. The aim of this research is to synthesize/design and develop a framework of novel control architectures which can result in complex powered vehicle subsystems to perform better with reduced exogeneuous information.
This research looks into the area of energy management by proposing an intelligent based system which not only looks at the beaten path of where energy comes from and how much of it to use, but it goes further by taking into consideration the world around it. By operating without GPS, it realies on data such as usage, average consumption, system loads and even other surrounding vehicles are considered when making the difficult decisions of where to direct the energy into, how much of it, and even when to cut systems off in benefit of others. All this is achieved in an integrated way by working within the limitations of non-fossil fuelled energy sources like fuel cells, ultracapacitors and battery banks using driver-provided information or by crafting an artificial usage profile from historicaly learnt data. By using an organic computing philosophy based on artificial intelligence this alternative approach to energy supply systems presents a different perspective beginning by accepting the fact that when hardware is set energy can be optimized only so much and takes a step further by answering the question of how to best manage it when refuelling might not be an option. The result is a situationally aware system concept that is portable to any type of electrically powered platform be it ground, aerial or marine since it operates on the fact that all operate within three dimensional space. The system´s capabilities are then verified in a virtual reality environment which can be tailored to the meet reseach needs including allowing for different altitudes, environmental temperature and humidity profiles. This VR system is coupled with a chassis dynamometer to allow for testing of real physical prototype unmanned ground vehicles where the intelligent system will benefit by learning from real platform data. The Thesis contributions and objectives are summarised next:
The control system proposed includes an awareness of the surroundings within which the vehicle is operating without relying on GPS position information.
The system proposed is portable and could be used to control other systems.
The test platform developed within the Thesis is flexible and could be used for other systems.
The control system for the fuel cell system described within the work has included an allowance for altitude and humidity. These factors would appear to be significant for such systems.
The structure of the control system and its hierarchy is novel.
The ability of the system to be applied to a UAV and as such control a ‘vehicle’ in 3 dimensions, and yet be also applied to a ground vehicle, where roll and pitch are largely a function of the ground over which it travels (so the UGV only uses a subset of the control functionality).
The mission awareness of the control structure appears to be the heart of the potential contribution to knowledge, and that this also includes the ability to create an estimated, artificial mission profile should one not be input by the operators. This learnt / adaptive input could be expanded on to highlight this aspect.
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Saravanan, Karthikeyan P. "Performance-aware energy optimizations in networks for HPC." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/404375.
Full textAbstract:
Energy efficiency is an important challenge in the field of High Performance Computing (HPC). High energy requirements not only limit the potential to realize next-generation machines but are also an increasing part of the total cost of ownership of an HPC system. While at large HPC systems are becoming increasingly energy proportional in an effort to reduce energy costs, interconnect links stand out for their inefficiency. Commodity interconnect links remain ¿always-on¿, consuming full power even when no data is being transmitted. Although various techniques have been proposed towards energy- proportional interconnects, they are often too conservative or are not focused toward HPC. Aggressive techniques for interconnect energy savings are often not applied to HPC, in particular, because they may incur excessive performance overheads. Any energy-saving technique will only be adopted in HPC if there is no significant impact on performance, which is still the primary design objective.
This thesis explores interconnect energy proportionality from a performance perspective. In this thesis, first a characterization of HPC applications is presented, making a case for the enormous potential for interconnect energy proportionality with HPC applications. Next, an HPC interconnect with on/off based links, modeled after the IEEE Energy Efficient Ethernet protocol, is evaluated. This evaluation while presenting a relationship between performance impact and energy over HPC applications also emphasizes the need for performance focused designs in energy efficient interconnects. Next, an adaptive mechanism, PerfBound, is presented that saves link energy subject to a bound on application performance overheads. Finally this evaluation structure is applied into an intermediate link power state, in addition to the traditional on and off states. Results of this study, over 15 production HPC applications show that, compared to current day always-on HPC interconnects, link energy can be reduced by unto 70%, while application performance overhead is bounded to only 1%.La eficiencia energética es un gran reto en el área de la Supercomputación (HPC), las grandes necesidades de energía no solo limitan el potencial de las computadoras de nueva generación, sino que también aumentan el coste de funcionamiento de estos sistemas. Mientras que los sistemas HPC tienden a ser cada vez más energéticamente proporcionales en un empeño por reducir costes, los enlaces de interconexión siguen siendo muy ineficientes. Los enlaces de interconexión comunes funcionan en modo "always-on", es decir, consumiendo energía incluso cuando no transmiten. Aunque se han propuesto algunas técnicas que ayuden a la proporcionalidad energética de los enlaces de interconexión, éstas han sido muy agresivas o poco enfocadas hacia su uso con sistemas HPC. Las técnicas de ahorro energético para los enlaces más agresivas no suelen ser utilizadas en HPC, particularmente porque degradan excesivamente el rendimiento. Cualquier técnica de ahorro energético solo será adoptada en sistemas HPC si no hay un impacto excesivo en el rendimiento, el cual es el principal objetivo de estos sistemas. En esta tesis, primeramente se presenta una nueva caracterización de aplicaciones HPC, remarcando el enorme potencial de la proporcionalidad en los enlaces de interconexión proporcionales para aplicaciones HPC. Seguidamente, se evaluará siguiendo el protocolo "IEEE Energy Efficient Ethernet" un link de interconexión on/off. Esta evaluación presentará una relación de impacto energético y rendimiento en aplicaciones HPC, enfatizando en la necesidad de usar un enlace de interconexión enfocados a la eficiencia. Se continuará con la presentación de un mecanismo adaptivo, PerfBound, que ahorra energía respetando unos límites máximos de impacto en el rendimiento. Finalmente, esta estructura es aplicada a un nuevo estado intermedio de funcionamiento adicional a los estados tradicionales on/off. Los resultados de este estudio, muestran que en más de 15 aplicaciones HPC la energía en los enlaces puede ser reducida en un 70% en comparación con enlaces "always-on", mientras que el impacto en el rendimiento es de tan solo un 1%.
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Fernández, Fernández Adriana. "Energy-aware routing techniques for software-defined networks." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/620620.
Full textAbstract:
Achieving energy efficiency has recently become a key topic of networking research due to the ever-increasing power consumption and CO2 emissions generated by large data networks. This problem is becoming even more concerning and challenging given the drastic traffic increase expected over the next few years. However, the use of efficient energy-aware strategies could overturn this situation reducing the electricity consumption of Internet data transmission networks, as well as contributing to mitigate the environmental impact of other sectors.
The existence of redundant network elements with high capacities is a common design practice in current network infrastructures in order to face suddenly failures or peak traffic flows. However, these additional resources remain either unused or barely used most of the time leading to an undesired energy waste. Therefore, putting into sleep mode (i.e. a low-power state) unused elements is an effective and widely-accepted strategy to decrease the consumption of data networks. In this context, SDN can be seen as an attractive solution to achieve the long-awaited energy efficiency in current communications systems, since they allow a flexible programmability suitable for this problem.
This doctoral thesis tackles the problem of optimizing the power consumption in SDN through the design of energy-aware routing techniques that minimize the number of network elements required to satisfy an incoming traffic load. Different from existing related works, we focus on optimizing energy consumption in SDN with in-band control traffic in order to close this important gap in the literature and provide solutions compatible with operational backbone networks.
Complementing the general aim of improving the energy efficiency in SDN, this research is also intended to cover important related features such as network performance, QoS requirements and real-time operation. Accordingly, this study gives a general perspective about the use of energy efficient routing techniques, which cover integrated routing considerations for the data and control plane traffic in SDN.
By using realistic input data, significant values of switched-off links and nodes are reached, which demonstrates the great opportunity for saving energy given by our proposals. The obtained results have also validated the intrinsic trade-off between environmental and performance concerns, considering several performance indicators. These findings confirm that energy-aware routing schemes should be designed considering specific traffic requirements and performance metric bounds. Moreover, it is shown that jointly considering QoS requirements and energy awareness is an effective approach to improve, not only the power consumption, but the performance on critical parameters such as control traffic delay and blocking rate. Similarly, the proposed dynamic traffic allocation with congestion-aware rerouting is able to handle demanding traffic arrival without degrading the performance of higher priority traffic.
In general, our proposals are fine-grained, easy to implement and quite balanced and effective in their results looking for a suitable and readily deployment in real-world SDN scenarios. Therefore, the conducted research and contributions reported through this document not only add to what is known about the potential of energy-aware routing techniques, but also stand as a valuable solution on the road to a sustainable networking.L'assoliment de l'eficiència energètica s'ha convertit recentment en un tema clau de recerca de xarxes a causa dels creixents nivells de consum d'energia i emissions de CO2 generats per les xarxes de dades. Aquest problema es torna cada vegada més preocupant i desafiant, donat el dràstic augment del trànsit esperat en els propers anys. No obstant això, l'ús d'estratègies energètiques eficients podria invertir aquesta situació, reduint el consum d'electricitat de les xarxes de dades d'Internet i contribuint a mitigar l'impacte ambiental d'altres sectors. L'existència d'elements de xarxa redundants i amb grans capacitats és una pràctica de disseny habitual en les infraestructures de xarxes actuals per afrontar fallades sobtades o fluxos de trànsit més elevats. Tanmateix, aquests recursos addicionals romanen poc o gens utilitzats la major part del temps, generant un desaprofitament d'energia no desitjat. Per tant, posar en mode de repòs (és a dir, un estat de baixa potència) elements no utilitzats és una estratègia efectiva i àmpliament acceptada per disminuir el consum en xarxes de dades. En aquest context, les xarxes definides per programari (SDN) es poden considerar una solució atractiva per aconseguir l'esperada eficiència energètica en els sistemes de comunicacions actuals, ja que permeten una flexible programabilitat idònia per a aquest problema. Aquesta tesi doctoral aborda el problema d'optimitzar el consum d'energia en SDN a través del disseny de tècniques d'encaminament conscients de l'energia que minimitzen la quantitat d'elements de xarxa necessaris per satisfer una càrrega de trànsit entrant. Diferent dels treballs existents, aquesta tesi es centra a optimitzar el consum d'energia en SDN amb el control de tràfic dins de banda per tancar aquesta important bretxa en la literatura i proporcionar solucions compatibles amb xarxes troncals operatives. Complementant l'objectiu general de millorar l'eficiència energètica en SDN, aquesta recerca també pretén cobrir altres importants paràmetres relacionats, com ara el rendiment de la xarxa, els requisits de qualitat de servei (QoS) i el funcionament en temps real. En conseqüència, aquest estudi ofereix una perspectiva general sobre l'ús de tècniques d'encaminament eficients energèticament, que contempla consideracions integrades per al tràfic de dades i del pla de control en SDN. Prenent dades d'entrada realistes, es van aconseguir desconnectar significatives quantitats d'enllaços i nodes, la qual cosa demostra la gran oportunitat d'estalvi d'energia que ofereixen les nostres propostes. Els resultats obtinguts també validen el estret compromís entre les preocupacions ambientals i les qüestions de rendiment de la xarxa, considerant diversos indicadors de rendiment. Aquests resultats confirmen que els esquemes d'encaminament conscients de l'energia s'han de dissenyar tenint en compte els requisits de tràfic específics i els límits desitjats de les mètriques de rendiment. A més, es demostra que, considerant conjuntament els requisits de QoS i de l'energia necessària, és un enfocament eficaç per millorar, no només el consum d'energia, sinó també el rendiment en paràmetres crítics, com la latència del tràfic de control i la probabilitat de bloqueig. De manera semblant, l'assignació dinàmica de tràfic proposta, amb re-encaminament conscient de la congestió, permet gestionar grans volums de trànsit sense degradar el rendiment de les demandes de major prioritat. En general, les nostres propostes són precises, fàcils d'implementar i bastant equilibrades i efectives en els seus resultats, buscant un desplegament adequat i fàcil en escenaris pràctics de SDN. Per tant, la recerca realitzada i les contribucions contingudes en aquest document no només afegeixen el que es coneix sobre el potencial de les tècniques d'encaminament conscients de l'energia, sinó que també representen una valuosa solució en el camí cap a una xarxa sostenible
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Suciu, Ioana. "Energy aware optimization for low power radio technologies." Doctoral thesis, Universitat Politècnica de Catalunya, 2020. http://hdl.handle.net/10803/668889.
Full textAbstract:
The explosive growth of IoT is pushing the market towards cheap, very low power devices with a strong focus on miniaturization, for applications such as in-body sensors, personal health monitoring and microrobots. Proposing procedures for energy efficiency in IoT is a difficult task, as it is a rapidly growing market comprised of many and very diverse product categories using technologies that are not stable, evolving at a high pace. The research in this field proposes solutions that go from physical layer optimization up to the network layer, and the sensor network designer has to select the techniques that are best for its application specific architecture and radio technology used. This work is focused on exploring new techniques for enhancing the energy efficiency and user experience of IoT networks. We divide the proposed techniques in frame and chip level optimization techniques, respectively. While the frame level techniques are meant to improve the performance of existing radio technologies, the chip level techniques aim at replacing them with crystal-free architectures.
The identified frame level techniques are the use of preamble authentication and packet fragmentation, advisable for Low Power Wide Area Networks (LPWANs), a technology that offers the lowest energy consumption per provided service, but is vulnerable in front of energy exhaustion attacks and does not perform well in dense networks. The use of authenticated preambles between the sensors and gateways becomes a defence mechanism against the battery draining intended by attackers. We show experimentally that this approach is able to reduce with 91% the effect of an exhaustion attack, increasing the device's lifetime from less than 0.24 years to 2.6 years. The experiments were conducted using Loadsensing sensor nodes, commercially used for critical infrastructure control and monitoring. Even if exemplified on LoRaWAN, the use of preamble authentication is extensible to any wireless protocol. The use of packet fragmentation despite the packet fits the frame, is shown to reduce the probability of collisions while the number of users in the duty-cycle restricted network increases. Using custom-made Matlab simulations, important goodput improvement was obtained with fragmentation, with higher impact in slower and denser networks. Using NS3 simulations, we showed that combining packet fragmentation with group NACK can increase the network reliability, while reducing the energy consumed for retransmissions, at the cost of adding small headers to each fragment. It is a strategy that proves to be effective in dense duty-cycle restricted networks only, where the headers overhead is negligible compared to the network traffic.
As a chip level technique, we consider using radios for communication that do not use external frequency references such as crystal oscillators. This would enable having all sensor's elements on a single piece of silicon, rendering it even ten times more energy efficient due to the compactness of the chip. The immediate consequence is the loss of communication accuracy and ability to easily switch communication channels. In this sense, we propose a sequence of frequency synchronization algorithms and phases that have to be respected by a crystal-free device so that it can be able to join a network by finding the beacon channel, synthesize all communication channels and then maintain their accuracy against temperature change. The proposed algorithms need no additional network overhead, as they are using the existing network signaling. The evaluation is made in simulations and experimentally on a prototype implementation of an IEEE802.15.4 crystal-free radio. While in simulations we are able to change to another communication channel with very good frequency accuracy, the results obtained experimentally show an initial accuracy slightly above 40ppm, which will be later corrected by the chip to be below 40 ppm.El crecimiento significativo de la IoT está empujando al mercado hacia el desarrollo de dispositivos de bajo coste, de muy bajo consumo energético y con un fuerte enfoque en la miniaturización, para aplicaciones que requieran sensores corporales, monitoreo de salud personal y micro-robots. La investigación en el campo de la eficiencia energética en la IoT propone soluciones que van desde la optimización de la capa física hasta la capa de red. Este trabajo se centra en explorar nuevas técnicas para mejorar la eficiencia energética y la experiencia del usuario de las redes IoT. Dividimos las técnicas propuestas en técnicas de optimización de nivel de trama de red y chip, respectivamente. Si bien las técnicas de nivel de trama están destinadas a mejorar el rendimiento de las tecnologías de radio existentes, las técnicas de nivel de chip tienen como objetivo reemplazarlas por arquitecturas que no requieren de cristales. Las técnicas de nivel de trama desarrolladas en este trabajo son el uso de autenticación de preámbulos y fragmentación de paquetes, aconsejables para redes LPWAN, una tecnología que ofrece un menor consumo de energía por servicio prestado, pero es vulnerable frente a los ataques de agotamiento de energía y no escalan frente la densificación. El uso de preámbulos autenticados entre los sensores y las pasarelas de enlace se convierte en un mecanismo de defensa contra el agotamiento del batería previsto por los atacantes. Demostramos experimentalmente que este enfoque puede reducir con un 91% el efecto de un ataque de agotamiento, aumentando la vida útil del dispositivo de menos de 0.24 años a 2.6 años. Los experimentos se llevaron a cabo utilizando nodos sensores de detección de carga, utilizados comercialmente para el control y monitoreo de infrastructura crítica. Aunque la técnica se ejemplifica en el estándar LoRaWAN, el uso de autenticación de preámbulo es extensible a cualquier protocolo inalámbrico. En esta tesis se muestra también que el uso de la fragmentación de paquetes a pesar de que el paquete se ajuste a la trama, reduce la probabilidad de colisiones mientras aumenta el número de usuarios en una red con restricciones de ciclos de transmisión. Mediante el uso de simulaciones en Matlab, se obtiene una mejora importante en el rendimiento de la red con la fragmentación, con un mayor impacto en redes más lentas y densas. Usando simulaciones NS3, demostramos que combinar la fragmentación de paquetes con el NACK en grupo se puede aumentar la confiabilidad de la red, al tiempo que se reduce la energía consumida para las retransmisiones, a costa de agregar pequeños encabezados a cada fragmento. Como técnica de nivel de chip, consideramos el uso de radios para la comunicación que no usan referencias de frecuencia externas como los osciladores basados en un cristal. Esto permitiría tener todos los elementos del sensor en una sola pieza de silicio, lo que lo hace incluso diez veces más eficiente energéticamente debido a la integración del chip. La consecuencia inmediata, en el uso de osciladores digitales en vez de cristales, es la pérdida de precisión de la comunicación y la capacidad de cambiar fácilmente los canales de comunicación. En este sentido, proponemos una secuencia de algoritmos y fases de sincronización de frecuencia que deben ser respetados por un dispositivo sin cristales para que pueda unirse a una red al encontrar el canal de baliza, sintetizar todos los canales de comunicación y luego mantener su precisión contra el cambio de temperatura. Los algoritmos propuestos no necesitan una sobrecarga de red adicional, ya que están utilizando la señalización de red existente. La evaluación se realiza en simulaciones y experimentalmente en una implementación prototipo de una radio sin cristal IEEE802.15.4. Los resultados obtenidos experimentalmente muestran una precisión inicial ligeramente superior a 40 ppm, que luego será corregida por el chip para que sea inferior a 40 ppm.
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Sankaran, Hariharan. "System level energy optimization for location aware computing." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001343.
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Bhatti, K. "Energy-aware Scheduling for Multiprocessor Real-time Systems." Phd thesis, Université de Nice Sophia-Antipolis, 2011. http://tel.archives-ouvertes.fr/tel-00599980.
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Les applications temps réel modernes deviennent plus exigeantes en termes de ressources et de débit amenant la conception d'architectures multiprocesseurs. Ces systèmes, des équipements embarqués au calculateur haute performance, sont, pour des raisons d'autonomie et de fiabilité, confrontés des problèmes cruciaux de consommation d'énergie. Pour ces raisons, cette thèse propose de nouvelles techniques d'optimisation de la consommation d'énergie dans l'ordonnancement de systèmes multiprocesseur. La premiére contribution est un algorithme d'ordonnancement hiérarchique á deux niveaux qui autorise la migration restreinte des tâches. Cet algorithme vise á réduire la sous-optimalité de l'algorithme global EDF. La deuxiéme contribution de cette thèse est une technique de gestion dynamique de la consommation nommée Assertive Dynamic Power Management (AsDPM). Cette technique, qui régit le contrôle d'admission des tâches, vise á exploiter de manière optimale les modes repos des processeurs dans le but de réduire le nombre de processeurs actifs. La troisiéme contribution propose une nouvelle technique, nommée Deterministic Stretch-to-Fit (DSF), permettant d'exploiter le DVFS des processeurs. Les gains énergétiques observés s'approchent des solutions déjà existantes tout en offrant une complexité plus réduite. Ces techniques ont une efficacité variable selon les applications, amenant á définir une approche plus générique de gestion de la consommation appelée Hybrid Power Management (HyPowMan). Cette approche sélectionne, en cours d'exécution, la technique qui répond le mieux aux exigences énergie/performance.
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Chan, Jeremy Computer Science & Engineering Faculty of Engineering UNSW. "Energy-aware synthesis for networks on chip architectures." Awarded by:University of New South Wales. School of Computer Science and Engineering, 2007. http://handle.unsw.edu.au/1959.4/35313.
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The Network on Chip (NoC) paradigm was introduced as a scalable communication infrastructure for future System-on-Chip applications. Designing application specific customized communication architectures is critical for obtaining low power, high performance solutions. Two significant design automation problems are the creation of an optimized configuration, given application requirement the implementation of this on-chip network. Automating the design of on-chip networks requires models for estimating area and energy, algorithms to effectively explore the design space and network component libraries and tools to generate the hardware description. Chip architects are faced with managing a wide range of customization options for individual components, routers and topology. As energy is of paramount importance, the effectiveness of any custom NoC generation approach lies in the availability of good energy models to effectively explore the design space. This thesis describes a complete NoC synthesis ???ow, called NoCGEN, for creating energy-efficient custom NoC architectures. Three major automation problems are addressed: custom topology generation, energy modeling and generation. An iterative algorithm is proposed to generate application specific point-to-point and packet-switched networks. The algorithm explores the design space for efficient topologies using characterized models and a system-level ???oorplanner for evaluating placement and wire-energy. Prior to our contribution, building an energy model required careful analysis of transistor or gate implementations. To alleviate the burden, an automated linear regression-based methodology is proposed to rapidly extract energy models for many router designs. The resulting models are cycle accurate with low-complexity and found to be within 10% of gate-level energy simulations, and execute several orders of magnitude faster than gate-level simulations. A hardware description of the custom topology is generated using a parameterizable library and custom HDL generator. Fully reusable and scalable network components (switches, crossbars, arbiters, routing algorithms) are described using a template approach and are used to compose arbitrary topologies. A methodology for building and composing routers and topologies using a template engine is described. The entire flow is implemented as several demonstrable extensible tools with powerful visualization functionality. Several experiments are performed to demonstrate the design space exploration capabilities and compare it against a competing min-cut topology generation algorithm.
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Yurur, Ozgur. "Energy Efficient Context-Aware Framework in Mobile Sensing." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4797.
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The ever-increasing technological advances in embedded systems engineering, together with the proliferation of small-size sensor design and deployment, have enabled mobile devices (e.g., smartphones) to recognize daily occurring human based actions, activities and interactions. Therefore, inferring a vast variety of mobile device user based activities from a very diverse context obtained by a series of sensory observations has drawn much interest in the research area of ubiquitous sensing. The existence and awareness of the context provides the capability of being conscious of physical environments or situations around mobile device users, and this allows network services to respond proactively and intelligently based on such awareness. Hence, with the evolution of smartphones, software developers are empowered to create context aware applications for recognizing human-centric or community based innovative social and cognitive activities in any situation and from anywhere. This leads to the exciting vision of forming a society of ``Internet of Things" which facilitates applications to encourage users to collect, analyze and share local sensory knowledge in the purpose for a large scale community use by creating a smart network which is capable of making autonomous logical decisions to actuate environmental objects. More significantly, it is believed that introducing the intelligence and situational awareness into recognition process of human-centric event patterns could give a better understanding of human behaviors, and it also could give a chance for proactively assisting individuals in order to enhance the quality of lives.
Mobile devices supporting emerging computationally pervasive applications will constitute a significant part of future mobile technologies by providing highly proactive services requiring continuous monitoring of user related contexts. However, the middleware services provided in mobile devices have limited resources in terms of power, memory and bandwidth as compared to the capabilities of PCs and servers. Above all, power concerns are major restrictions standing up to implementation of context-aware applications. These requirements unfortunately shorten device battery lifetimes due to high energy consumption caused by both sensor and processor operations. Specifically, continuously capturing user context through sensors imposes heavy workloads in hardware and computations, and hence drains the battery power rapidly. Therefore, mobile device batteries do not last a long time while operating sensor(s) constantly.
In addition to that, the growing deployment of sensor technologies in mobile devices and innumerable software applications utilizing sensors have led to the creation of a layered system architecture (i.e., context aware middleware) so that the desired architecture can not only offer a wide range of user-specific services, but also respond effectively towards diversity in sensor utilization, large sensory data acquisitions, ever-increasing application requirements, pervasive context processing software libraries, mobile device based constraints and so on. Due to the ubiquity of these computing devices in a dynamic environment where the sensor network topologies actively change, it yields applications to behave opportunistically and adaptively without a priori assumptions in response to the availability of diverse resources in the physical world as well as in response to scalability, modularity, extensibility and interoperability among heterogeneous physical hardware.
In this sense, this dissertation aims at proposing novel solutions to enhance the existing tradeoffs in mobile sensing between accuracy and power consumption while context is being inferred under the intrinsic constraints of mobile devices and around the emerging concepts in context-aware middleware framework.
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Wilke, Claas. "Energy-Aware Development and Labeling for Mobile Applications." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-139391.
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Today, mobile devices such as smart phones and tablets have become ubiquitous and are used everywhere. Millions of software applications can be purchased and installed on these devices, customizing them to personal interests and needs. However, the frequent use of mobile devices has let a new problem become omnipresent: their limited operation time, due to their limited energy capacities.
Although energy consumption can be considered as being a hardware problem, the amount of energy required by today’s mobile devices highly depends on their current workloads, being highly influenced by the software running on them. Thus, although only hardware modules are consuming energy, operating systems, middleware services, and mobile applications highly influence the energy consumption of mobile devices, depending on how efficient they use and control hardware modules. Nevertheless, most of today’s mobile applications totally ignore their influence on the devices’ energy consumption, leading to energy wastes, shorter operation times, and thus, frustrated application users. A major reason for this energy-unawareness is the lack for appropriate tooling for the development of energy-aware mobile applications.
As many mobile applications are today behaving energy-unaware and various mobile applications providing similar services exist, mobile application users aim to optimize their devices by installing applications being known as energy-saving or energy-aware; meaning that they consume less energy while providing the same services as their competitors. However, scarce information on the applications’ energy usage is available and, thus, users are forced to install and try many applications manually, before finding the applications fulfilling their personal functional, non-functional, and energy requirements.
This thesis addresses the lack of tooling for the development of energy-aware mobile applications and the lack of comparability of mobile applications in terms of energy-awareness with the following two contributions: First, it proposes JouleUnit, an energy profiling and testing framework using unit-tests for the execution of application workloads while profiling their energy consumption in parallel. By extending a well-known testing concept and providing tooling integrated into the development environment Eclipse, JouleUnit requires a low learning curve for the integration into existing development and testing processes. Second, for the comparability of mobile applications in terms of energy efficiency, this thesis proposes an energy benchmarking and labeling service. Mobile applications belonging to the same usage domain are energy-profiled while executing a usage-domain specific benchmark in parallel. Thus, their energy consumption for specific use cases can be evaluated and compared afterwards. To abstract and summarize the profiling results, energy labels are derived that summarize the applications’ energy consumption over all evaluated use cases as a simple energy grade, ranging from A to G. Besides, users can decide how to weigh specific use cases for the computation of energy grades, as it is likely that different users use the same applications differently. The energy labeling service has been implemented for Android applications and evaluated for three different usage domains (being web browsers, email clients, and live wallpapers), showing that different mobile applications indeed differ in their energy consumption for the same services and, thus, their comparison is both possible and sensible. To the best of my knowledge, this is the first approach providing mobile application users comparable energy consumption information on mobile applications without installing and testing them on their own mobile devices.
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Roberts, Stephen I. "Energy-aware performance engineering in high performance computing." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/107784/.
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Advances in processor design have delivered performance improvements for decades. As physical limits are reached, however, refinements to the same basic technologies are beginning to yield diminishing returns. Unsustainable increases in energy consumption are forcing hardware manufacturers to prioritise energy efficiency in their designs. Research suggests that software modifications will be needed to exploit the resulting improvements in current and future hardware. New tools are required to capitalise on this new class of optimisation. This thesis investigates the field of energy-aware performance engineering. It begins by examining the current state of the art, which is characterised by ad-hoc techniques and a lack of standardised metrics. Work in this thesis addresses these deficiencies and lays stable foundations for others to build on. The first contribution made includes a set of criteria which define the properties that energy-aware optimisation metrics should exhibit. These criteria show that current metrics cannot meaningfully assess the utility of code or correctly guide its optimisation. New metrics are proposed to address these issues, and theoretical and empirical proofs of their advantages are given. This thesis then presents the Power Optimised Software Envelope (POSE) model, which allows developers to assess whether power optimisation is worth pursuing for their applications. POSE is used to study the optimisation characteristics of codes from the Mantevo mini-application suite running on a Haswell-based cluster. The results obtained show that of these codes TeaLeaf has the most scope for power optimisation while PathFinder has the least. Finally, POSE modelling techniques are extended to evaluate the system-wide scope for energy-aware performance optimisation. System Summary POSE allows developers to assess the scope a system has for energy-aware software optimisation independent of the code being run.
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Alsughayyir, Aeshah Yahya. "Energy-aware scheduling in decentralised multi-cloud systems." Thesis, University of Leicester, 2018. http://hdl.handle.net/2381/42407.
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Cloud computing is an emerging Internet-based computing paradigm that aims to provide many on-demand services, requested nowadays by almost all online users. Although it greatly utilises virtualised environments for applications to be executed efficiently in low-cost hosting, it has turned energy wasting and overconsumption issues into major concerns. Many studies have projected that the energy consumption of cloud data-centres would grow significantly to reach 35% of the total energy consumed worldwide, threatening to further boost the world's energy crisis. Moreover, cloud infrastructure is built on a great amount of server equipment, including high performance computing (HPC), and the servers are naturally prone to failures. In this thesis, we study practically as well as theoretically the feasibility of optimising energy consumption in multi-cloud systems. We explore a deadline-based scheduling problem of executing HPC-applications by a heterogeneous set of clouds that are geographically distributed worldwide. We assume that these clouds participate in a federated approach. The practical part of the thesis has focused on combining two energy dimensions while scheduling HPC-applications (i.e., energy consumed for execution and data transmission). It has considered simultaneously minimising application rejections and deadline violations, to support resource reliability, with energy optimisation. In the theoretical part, we have presented the first online algorithms for the non-pre-emptive scheduling of jobs with agreeable deadlines on heterogeneous parallel processors. Through our developed simulation and experimental analysis using real parallel workloads from large-scale systems, the results evidenced that it is possible to reduce a considerable amount of energy while carefully scheduling cloud applications over a multi-cloud system. We have shown that our practical approaches provide promising energy savings with acceptable level of resource reliability. We believe that our scheduling approaches have particular importance in relation with the main aim of green cloud computing for the necessity of increasing energy efficiency.
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Angelopoulos, Georgios Ph D. Massachusetts Institute of Technology. "Energy-aware network coding circuit and system design." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66021.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 73-78).
Network Coding (NC) has been shown to provide several advantages in communication networks in terms of throughput, data robustness and security. However, its applicability to networks with resource constrained nodes, like Body Area Networks (BANs), has been questioned due to its complexity requirements. Proposed NC implementations are based on high-end CPUs and GPUs, consuming hundreds of Watts, without providing enough insight about its energy requirements. As more and more mobile devices, sensors and other low power systems are used in modern communication protocols, a highly efficient and optimized implementation of NC is required. In this work, an effort is made to bridge NC theory with ultra low power applications. For this reason, an energy-scalable, low power accelerator is designed in order to explore the minimum energy requirements of NC. Based on post-layout simulation results using a TSMC 65nm process, the proposed encoder consumes 22.15 uW at 0.4V, achieving a processing throughput of 80 MB/s. These numbers reveal that NC can indeed be incorporated into resource constrained networks with battery-operated or even energy scavenging nodes. Apart from the hardware design, a new partial packet recovery mechanism based on NC, called PPRNC, is proposed. PPRNC exploits information contained in partial packets, similarly to existing Hybrid-ARQ schemes, but with a PHY-agnostic approach. Minimization of the number of retransmitted packets saves transmission energy and results in higher total network throughput, making PPRNC an attractive candidate for energy constrained networks, such as BANs, as well as modern, high-speed wireless mesh networks. The proposed mechanism is analyzed and implemented using commercial development boards, validating its ability to extract information contained from partial packets.
by Georgios Angelopoulos.
S.M.
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Hamad, F. M. "Energy-aware encryption mechanism for m-commerce devices." Thesis, Coventry University, 2010. http://curve.coventry.ac.uk/open/items/61037dc3-74e7-8cea-8e44-75f643220d0d/1.
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With the wide spread of mobile phones, PDAs, and Smartphones, M-Commerce has become a major application domain for mobile devices, unlike conventional wired networks, mobile devices allow the user to conduct online transactions regardless of the time and the place as long as there is mobile network coverage. However, online transactions require adequate level of security to insure the confidentiality, the integrity, and the availability of the user’s information. Security measures consume a considerable amount of energy and require more time in processing. The aim of this thesis is to optimise the energy and the resources consumption of mobile phones when applying variant symmetric and asymmetric schemes. This aim can be achieved through developing A System State Security Management Framework, SSSM, which will implement encryption schemes, symmetric and asymmetric, and will provide different options to enable the user to choose the type of encryption, the key size, and number of rounds of computation to optimise the energy consumption level of the mobile phone. This thesis compares the power and the resources consumed by the most commonly used encryption algorithms such as CAST, IDEA, Triple-DES, RSA, and AlGamal. This comparison helps to draw the advantages and disadvantages of each algorithm scheme used in reference to the security level it provides and the power it consumes. Implementing this mechanism will enhance the performance of mobile phones by increasing the security levelsprovided by the encryption schemes and utilising the limited power and resources efficiency. Therefore, confidentiality will be presented in mobile phones and variant encryption schemes, symmetric and asymmetric, and changeable key sizes and rounds, will ensure the authenticity of both senders and recipients depending on their needs as well as resources available. This research makes contributions in two major areas; the first area consists of the novel Energy Aware Encryption polices generated by this work, the second area of contribution is the energy measurements and experimental results which validate the approach presented in the research.
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Rukpakavong, Wilawan. "Energy-efficient and lifetime aware routing in WSNs." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/14497.
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Network lifetime is an important performance metric in Wireless Sensor Networks (WSNs). Transmission Power Control (TPC) is a well-established method to minimise energy consumption in transmission in order to extend node lifetime and, consequently, lead to solutions that help extend network lifetime. The accurate lifetime estimation of sensor nodes is useful for routing to make more energy-efficient decisions and prolong lifetime. This research proposes an Energy-Efficient TPC (EETPC) mechanism using the measured Received Signal Strength (RSS) to calculate the ideal transmission power. This includes the investigation of the impact factors on RSS, such as distance, height above ground, multipath environment, the capability of node, noise and interference, and temperature. Furthermore, a Dynamic Node Lifetime Estimation (DNLE) technique for WSNs is also presented, including the impact factors on node lifetime, such as battery type, model, brand, self-discharge, discharge rate, age, charge cycles, and temperature. In addition, an Energy-Efficient and Lifetime Aware Routing (EELAR) algorithm is designed and developed for prolonging network lifetime in multihop WSNs. The proposed routing algorithm includes transmission power and lifetime metrics for path selection in addition to the Expected Transmission Count (ETX) metric. Both simulation and real hardware testbed experiments are used to verify the effectiveness of the proposed schemes. The simulation experiments run on the AVRORA simulator for two hardware platforms: Mica2 and MicaZ. The testbed experiments run on two real hardware platforms: the N740 NanoSensor and Mica2. The corresponding implementations are on two operating systems: Contiki and TinyOS. The proposed TPC mechanism covers those investigated factors and gives an overall performance better than the existing techniques, i.e. it gives lower packet loss and power consumption rates, while delays do not significantly increase. It can be applied for single-hop with multihoming and multihop networks. Using the DNLE technique, node lifetime can be predicted more accurately, which can be applied for both static and dynamic loads. EELAR gives the best performance on packet loss rate, average node lifetime and network lifetime compared to the other algorithms and no significant difference is found between each algorithm with the packet delay.
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Peng, Tingqing. "WSN Routing Schedule Based on Energy-aware Adaptation." Thesis, Mittuniversitetet, Institutionen för informationssystem och –teknologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39223.
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In view of the problem of uneven load distribution and energy consumption among nodes in a multi-hop wireless sensor network, this research constructs the routing schedule problem as a MOP (Multi-objective Optimization Problem), and proposed an energy-aware routing optimization scheme RDSEGA based on multi-objective optimization. In this scheme, in order to avoid the searching space explosion problem caused by the increase of nodes, KSP Yen's algorithm was applied to prune the searching space, and the candidate paths selected after pruning are recoded based on priority. Then adopted the improved strengthen elitist genetic algorithm to get the entire network routing optimization scheme with the best energy efficiency. At the same time, in view of the problem of routing discontinuity in the process of path crossover and mutation, new crossover and mutation method was proposed that based on the gene fragments connected by the adjacent node or the same node to maximize the effectiveness of the evolution result. The experimental results prove that the scheme reduced the energy consumption of nodes in the network, the load between nodes becomes more balanced, and the working time of the network has been prolonged nearly 40% after the optimization. This brings convenience to practical applications, especially for those that are inconvenient to replace nodes.