Dissertations / Theses: 'Connected networks'

1

Bai, Xiaole. "Optimal Connected Coverage for Wireless Sensor Networks." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259772831.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Kim, Kyoung Min Sun Min-Te. "Multi initiator connected dominating set construction for mobile ad hoc networks." Auburn, Ala, 2008. http://hdl.handle.net/10415/1549.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Hill, Robert M. Martin Barbara N. "Leadership capacity in a complex connected age." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/7033.

Full text

Abstract:

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 26, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Barbara N. Martin. Vita. Includes bibliographical references.

APA, Harvard, Vancouver, ISO, and other styles

4

Liu, Feng. "Symmetrically multi-connected optical fiber wide area networks." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6704.

Full text

Abstract:

Self-routing all-optical WAN design is becoming more and more important in broadband communications. However, little has been done in this field. In this thesis, we propose a Multi-Dual Ring Connected Shuffle Network and a Multi-Shuffle Connected Shuffle Network for a WAN environment. The performance of the proposed architectures is studied under a uniform traffic pattern analytically and numerical results are provided. The Multi-Dual Ring Connected Shuffle Connected Networks are studied under the nonuniform traffic patterns with an analytical method 'extreme value analysis' and a simulation method 'random load generation'. All of the studies are done with respect to the Perfect Shuffle Networks. The proposed architectures outperform the conventional Perfect Shuffle Network proposed in the literature.

APA, Harvard, Vancouver, ISO, and other styles

5

Canning, Andrew Magnus. "Ising spin models of partially connected neural networks." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/13304.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Mabuza, Sicelo Msuthu. "Stability of distribution networks connected with distributed generation." Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/22460.

Full text

Abstract:

Bibliography: pages 164-167.
This thesis describes an investigation into the stability of distribution networks that are connected with distributed generators. Due to the restructuring of the electricity industry in the region as well as environmental concerns, distributed generation is bound to increase at a higher rate in the Southern African region in the near future. Southern Africa, like many other developing regions, is dominated by electrically weak distribution networks that have relatively high impedance lines. These networks suffer extreme voltage fluctuations when a transient disturbance occurs on the network. The distributed generators are connected onto distribution networks that were designed to operate without any generation, but were designed to receive power from the transmission networks. Once distributed generators are connected to distribution networks, a number of technical challenges are presented. One of the technical challenges includes investigating the stability of distribution networks connected with distributed generation. It would be beneficial to know what effect the connection of distributed generators onto distribution networks would have on the system stability. This is because if the connection of distributed generators onto distribution networks increases instability on the network, the quality of supply of that network would be degraded, therefore the connection of distributed generators must be limited or methods of improving the stability must be implemented. It is important to establish the measures that can be taken to make sure that the generators react in a stable manner when subjected to disturbances and to make sure that the local system stability is not compromised. The first objective of this thesis was to identify the types of generators that are likely to be connected to Southern African distribution networks and investigate their stability. The next objective was to design model distribution networks that would be utilised to highlight key stability issues that are raised when distributed generation is connected to distribution networks. The third objective was to conduct and analyse stability studies on model as well as existing Southern African distribution networks connected with distributed generation, including the assessment of the implications of potential instability such as on the quality of supply. The last objective was to identify various ways of improving the stability of distribution networks that are connected with distributed generation.

APA, Harvard, Vancouver, ISO, and other styles

7

Hiselius, Leo. "Stimulus representation in anisotropically connected spiking neural networks." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300153.

Full text

Abstract:

Biological neuronal networks are a key object of study in the field of computational neuroscience, and recent studies have also shown their potential applicability within artificial intelligence and robotics [1]. They come in many shapes and forms, and a well known and widely studied example is the liquid state machine from 2004 [2]. In 2019, a novel and simple connectivity rule was presented with the introduction of the SpreizerNet [3]. The connectivity of the SpreizerNet is governed by a type of gradient noise known as Perlin noise, and as such the connectivity is anisotropic but correlated. The spiking activity produced in the SpreizerNet is possibly functionally relevant, e.g. for motor control or classification of input stimuli. In 2020, it was shown to be useful for motor control [4]. In this Master’s thesis, we inquire if the spiking activity of the SpreizerNet is functionally relevant in the context of stimulus representation. We investigate how input stimulus from the MNIST handwritten digits dataset is represented in the spatio-temporal activity sequences produced by the SpreizerNet, and whether this representation is sufficient for separation. Furthermore, we consider how the parameters governing the local structure of connectivity impacts representation and separation. We find that (1) the SpreizerNet separates input stimulus at the initial stage after stimulus and (2) that separation decreases with time when the activity from dissimilar inputs becomes unified.
Biologiska neurala nätverk är ett centralt studieobjekt inom beräkningsneurovetenskapen, och nyliga studier har även visat deras potentiella applicerbarhet inom artificiell intelligens och robotik [1]. De kan formuleras på många olika sätt, och ett välkänt och vida studerat exempel är liquid state machine från 2004 [2]. 2019 presenterades en ny och enkel kopplingsregel i SpreizerNätverket [3]. Kopplingarna i SpreizerNätverket styrs av en typ av gradientbrus vid namn Perlinbrus, och som sådana är de anisotropiska men korrelerade. Spikdatan som genereras av SpreizerNätverket är möjligtvis betydelsefull för funktion, till exempel för motorisk kontroll eller separation av stimuli. 2020 visade Michaelis m. fl. att spikdatan var relevant för motorisk kontroll [4]. I denna masteruppsats frågar vi oss om spikdatan är funktionellt relevant för stimulusrepresentation. Vi undersöker hur stimulus från MNIST handwritten digits -datasetet representeras i de spatiotemporella aktivitetssekvenserna som genereras i SpreizerNätverket, och huruvida denna representation är tillräcklig för separation.Vidare betraktar vi hur parametrarna som styr den lokala kopplingsstrukturen påverkar representation och separation. Vi visar att (1) SpreizerNätverket separerar stimuli i ett initialt skede efter stimuli och (2) att separationen minskar med tid när aktiviteten från olika stimuli blir enhetlig.

APA, Harvard, Vancouver, ISO, and other styles

8

Makke, Ali. "Pervasive Service Provisioning in Intermittently Connected Hybrid Networks." Thesis, Lorient, 2015. http://www.theses.fr/2015LORIS362/document.

Full text

Abstract:

La vision de l'informatique ubiquitaire permettant de construire des espaces intelligents interactifs dans l'environnement physique passe, peu à peu, du domaine de la recherche à la réalité. La capacité de calcul ne se limite plus à l'ordinateur personnel mais s'intègre dans de multiples appareils du quotidien, et ces appareils deviennent, grâce à plusieurs interfaces, capables de communiquer directement les uns avec les autres ou bien de se connecter à Internet.Dans cette thèse, nous nous sommes intéressés à un type d'environnement cible de l'informatique ubiquitaire qui forme ce que nous appelons un réseau hybride à connexions intermittentes (ICHN). Un ICHN est un réseau composé de deux parties : une partie fixe et une partie mobile. La partie fixe est constituée de plusieurs infostations fixes (potentiellement reliées entre elles avec une infrastructure fixe, typiquement l'Internet). La partie mobile, quant à elle, est constituée de smartphones portés par des personnes nomades. Tandis que la partie fixe est principalement stable, la partie mobile pose un certain nombre de défis propres aux réseaux opportunistes. En effet, l'utilisation de moyens de communication à courte portée couplée à des déplacements de personnes non contraints et à des interférences radio induit des déconnexions fréquentes. Le concept du "store, carry and forward" est alors habituellement appliqué pour permettre la communication sur l'ensemble du réseau. Avec cette approche, un message peut être stocké temporairement sur un appareil avant d'être transféré plus tard quand les circonstances sont plus favorables. Ainsi, n'importe quel appareil devient un relai de transmission opportuniste qui permet de faciliter la propagation d'un message dans le réseau. Dans ce contexte, la fourniture de services est particulièrement problématique, et exige de revisiter les composants principaux du processus de fourniture, tels que la découverte et l'invocation de service, en présence de ruptures de connectivité et en l'absence de chemins de bout en bout. Cette thèse aborde les problèmes de fourniture de service sur l'ensemble d'un ICHN et propose des solutions pour la découverte de services, l'invocation et la continuité d'accès. En ce qui concerne le défi de la découverte de services, nous proposons TAO-DIS, un protocole qui met en œuvre un mécanisme automatique et rapide de découverte de services. TAO-DIS tient compte de la nature hybride d'un ICHN et du fait que la majorité des services sont fournis par des infostations. Il permet aux utilisateurs mobiles de découvrir tous les services dans l'environnement afin d'identifier et de choisir les plus intéressants. Pour permettre aux utilisateurs d'interagir avec les services découverts, nous introduisons TAO-INV. TAO-INV est un protocole d'invocation de service spécialement conçu pour les ICHN. Il se fonde sur un ensemble d'heuristiques et de mécanismes qui assurent un acheminement efficace des messages (des requêtes et des réponses de services) entre les infostations fixes et les clients mobiles tout en conservant un surcoût et des temps de réponses réduits. Puisque certaines infostations dans le réseau peuvent être reliées entre elles, nous proposons un mécanisme de continuité d'accès (handover) qui modifie le processus d'invocation pour réduire les délais de délivrance. Dans sa définition, il est tenu compte de la nature opportuniste de la partie mobile de l'ICHN. Nous avons mené diverses expérimentations pour évaluer nos solutions et les comparer à d'autres protocoles conçus pour des réseaux ad hoc et des réseaux opportunistes. Les résultats obtenus tendent à montrer que nos solutions surpassent ces autres protocoles, notamment grâce aux optimisations que nous avons développées pour les ICHN. À notre avis, construire des protocoles spécialisés qui tirent parti des techniques spécifiquement conçues pour les ICHN est une approche à poursuivre en complément des recherches sur des protocoles de communication polyvalents
The vision of pervasive computing of building interactive smart spaces in the physical environment is gradually heading from the research domain to reality. Computing capacity is moving beyond personal computers to many day-to-day devices, and these devices become, thanks to multiple interfaces, capable of communicating directly with one another or of connecting to the Internet.In this thesis, we are interested in a kind of pervasive computing environment that forms what we call an Intermittently Connected Hybrid Network (ICHN). An ICHN is a network composed of two parts: a fixed and a mobile part. The fixed part is formed of some fixed infostations (potentially connected together with some fixed infrastructure, typically the Internet). The mobile part, on the other hand, is formed of smartphones carried by nomadic people. While the fixed part is mainly stable, the mobile part is considered challenging and form what is called an Opportunistic Network. Indeed, relying on short-range communication means coupled with the free movements of people and radio interferences lead to frequent disconnections. To perform a network-wide communication, the "store, carry and forward" approach is usually applied. With this approach, a message can be stored temporarily on a device, in order to be forwarded later when circumstances permit. Any device can opportunistically be used as an intermediate relay to facilitate the propagation of a message from one part of the network to another. In this context, the provisioning of pervasive services is particularly challenging, and requires revisiting important components of the provisioning process, such as performing pervasive service discovery and invocation with the presence of connectivity disruptions and absence of both end-to-end paths and access continuity due to user mobility. This thesis addresses the problems of providing network-wide service provisioning in ICHNs and proposes solutions for pervasive service discovery, invocation and access continuity. Concerning service discovery challenge, we propose TAO-DIS, a service discovery protocol that performs an automatic and fast service discovery mechanism. TAO-DIS takes into account the hybrid nature of an ICHN and that the majority of services are provided by infostations. It permits mobile users to discover all the services in the surrounding environment in order to identify and choose the most convenient ones. To allow users to interact with the discovered services, we introduce TAO-INV. TAO-INV is a service invocation protocol specifically designed for ICHNs. It relies on a set of heuristics and mechanisms that ensures performing efficient routing of messages (both service requests and responses) between fixed infostations and mobile clients while preserving both low values of overhead and round trip delays. Since some infostations in the network might be connected, we propose a soft handover mechanism that modifies the invocation process in order to reduce service delivery delays. This handover mechanism takes into consideration the opportunistic nature of the mobile part of the ICHN. We have performed various experiments to evaluate our solutions and compare them with other protocols designed for ad hoc and opportunistic networks. The obtained results tend to prove that our solutions outperform these protocols, namely thanks to the optimizations we have developed for ICHNs. In our opinion, building specialized protocols that benefit from techniques specifically designed for ICHNs is an approach that should be pursued, in complement with research works on general-purpose communication protocols

APA, Harvard, Vancouver, ISO, and other styles

9

Shishani, Basel. "Segmentation of connected text using constrained neural networks." Thesis, Queensland University of Technology, 1997.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

10

MILES, RICHARD BRENT. "STRONGLY CONNECTED COMPONENTS AND STEADY STATES IN GENE REGULATORY NETWORKS." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1195439442.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Alotaibi, Maryam. "Relay Selection for Heterogeneous Transmission Powers in Connected Vehicles." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36087.

Full text

Abstract:

It is widely believed that the advances of Vehicle-to-Vehicle (V2V) communications will help to remodel the prospect of road transportation systems. By virtue of V2V communications, information generated by the vehicle control system, on-board sensors or passengers can be effectively disseminated among vehicles in proximity, or to vehicles in multiple hops away in a vehicular ad-hoc network (VANET). Without assistance from any built infrastructure, a variety of active road safety applications (e.g., Vehicle-Based Road Condition Warning, Cooperative Collision Warning, Approaching Emergency Vehicle Warning) and traffic efficiency management applications (e.g., Wrong Way Driver Warning) are enabled by inter-vehicle wireless links. The purpose of connecting vehicle technologies is to improve road safety, awareness, and transportation systems efficiency. The Wireless Access for Vehicular Environments (WAVE) technology/Dedicated Short-Range Communications (DSRC) is the main enabling wireless technology for both V2V and vehicle-to-Infrastructure (V2I) communications. From USDOT and stakeholders detailed analysis, it is resolved that WAVE is the only viable option for critical safety and other low latency mobility and environmental applications. WAVE technology has reached to a mature stage and a basic V2V system is expected to be deployed in the next few years. In the late part of 2015, USDOT announce that WAVE is sufficiently robust to proceed with the preparation for deployment of connected vehicle environments. The USDOT has created a roadmap with preliminary plans to guide industries and public agencies implementation efforts. However, there are persisting major concerns regarding the V2V initiative needing more analysis and testing. One of the concerns is the channel congestion. Channel congestion may impact WAVE effectiveness, which may in turn impact the effectiveness of supported safety applications. Suggested solutions to mitigate congestion are focused on supporting adaptive control of the message transmission power. The Institute of Electrical and Electronics Engineers (IEEE), and European Telecommunications Standards Institute (ETSI) have included transmit power component per packet to be used for channel congestion control mechanism. The adjustment of transmission powers has created an environment of vehicles with different transmission powers. Such environment will affect the performance of the proposed protocols to disseminate warning messages. It may also affect the performance of periodic beaconing that is required by most of the safety applications. Thus far, several protocols have been proposed to help identify appropriate relay vehicles. However, such approaches neglect the fact that vehicle transmission ranges are typically heterogeneous due to different transmission power values or dynamic adjustment of power to alleviate congestion. The proper selection of relay nodes governs high delivery ratio, acceptable overall end-to-end delay and efficient bandwidth usage. In this work, area-based relay selection protocols that work in heterogeneous transmission powers are introduced. Mathematical functions are developed for a timer and decision probability to be used by each vehicle receiving the message. The values of the two functions allow the vehicle to determine if it is the next to act as relay node or not. Geometric taxonomy for all possible overlap patterns in wireless environment is constructed with the related math calculations. Moreover, an adaptive expiry time for neighbours-table entries that harmonizes with dynamic beacon scheduling is proposed.

APA, Harvard, Vancouver, ISO, and other styles

12

Cotton, Nicholas Jay Wilamowski Bogdan M. "Training arbitrarily connected neural networks with second order algorithms." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Electrical_and_Computer_Engineering/Thesis/Cotton_Nicholas_30.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Hou, Xiang. "Maximizing data preservation time in intermittently connected sensor networks." Thesis, Wichita State University, 2012. http://hdl.handle.net/10057/5398.

Full text

Abstract:

In intermittently connected sensor networks, wherein sensor nodes do have connected paths to the base station periodically, preserving generated data inside the network is a new and challenging problem. We propose to preserve data items by distributing them from storage-depleted data generating nodes to sensor nodes with available storage space and high battery energy, under the constraints that each node has limited storage capacity and battery power. The goal is to maximize the minimum remaining energy among the nodes storing data items, in order to preserve them for maximum amount of time until next uploading opportunity arises. We refer to this problem as storage-depletion induced data preservation problem (SDP). First, we give feasibility condition of this issue by proposing and applying a Modified Edmonds-Karp Algorithm (MEA) on an appropriately transformed flow network. We then show that when feasible solutions exist, finding the optimal solution is NP-hard. Moreover, we develop a sufficient condition to solve SDP optimally. Finally, we design a distributed algorithm with less time complexity then compare it with flow based algorithm then show via simulations that distributed algorithm performs close to optimal solution.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science

APA, Harvard, Vancouver, ISO, and other styles

14

Weaver, Stephen T. "Connected Consumers: Cognizance of Provision Networks in Mundane Consumption." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/marketing_diss/22.

Full text

Abstract:

Many types of product meanings have been investigated in the consumer behavior literature, and these layers of meaning have been shown to influence consumer behavior. However, very little research has attempted to investigate product meanings having to do with provision networks, that is, the people, places, resources and processes involved in creating products and delivering them to the consumer. In addition, researchers in several fields have argued that consumers have lost an awareness of provision networks due to their increasing size and complexity in the modern economy. This research indicates that some consumers are indeed cognizant of the systems of provision for the products they consume. The results of this study indicate that some consumers expend effort to create and ascribe provision meanings for some products, and that these meanings in turn affect the consumer’s consumption decisions and experiences. In spite of the commodifying effects of modern market systems, these consumers exhibit an appreciation for products as the outcome of a complex system of relationships among people, places, resources and processes and have thus become reconnected to the provision of what they consume.

APA, Harvard, Vancouver, ISO, and other styles

15

Raza, Shahid. "Securing Communication in IP-Connected Industrial Wireless Sensor Networks." Licentiate thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-12261.

Full text

Abstract:

With the advent of wireless sensor networks (WSN) and success of wirelesscommunication in the local and personal area networks such asWi-Fi and Bluetoothmore serious efforts to apply standard wireless communication in sensitiveindustrial networks were initiated. This effort resulted in the standardizationof WirelessHART. Other standardization efforts include ISA 100.11a andZigBee. Keeping in mind the nature of wireless communication and sensitivityof industrial environments security of these network gets greater importance. In this thesis we work on security issues in industrial WSN in general andIP-connected WSN in particular. Currently WirelessHART is the only approvedstandard for secure wireless communication in industrial WSNs. Westart our work with the analysis of security mechanisms in WirelessHART.We propose solutions for the security shortcomings in WirelessHART, and designand implement the missing security components. Particularly, we specify,design, implement, and evaluate the first open security manager for WirelessHARTnetworks. With the standardization of IP in WSNs (6LoWPAN) and birth of Internetof Things the need for IP communication in industrial WSN is getting importance.The recently proposed ISA 100.11a standard is IP-based since its inception.Also standardization efforts are in progress to apply IP in WirelessHARTand Zigbee. Recently, WSNs and traditional IP networks are more tightly integratedusing IPv6 and 6LoWPAN. We realize the importance of having aninteroperable standardized secure IP communication in industrial WSNs. IPSecurity (IPsec) is a mandatory security solution in IPv6. We propose to useIPsec for 6LoWPAN enabled industrial WSNs. However, it is not meaningfulto use IPsec in its current form in resource constrained WSNs. In additionto providing security solutions for WirelessHART, in this thesis we also specify,design, implement, and extensively evaluate lightweight IPsec that enablesend-to-end secure communication between a node in a 6LoWPAN and a device in the traditional Internet. Our results show that lightweight IPsec is a sensibleand practical solution for securing WSN.

APA, Harvard, Vancouver, ISO, and other styles

16

Hogan, James M. "Recruitment learning in randomly connected neural netwworks." Thesis, Queensland University of Technology, 2000.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

17

Cheung, Steven. "Packet routing on mesh-connected computers /." [Hong Kong] : University of Hong Kong, 1992. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13209607.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Sanchez, Juan Sebastiam. "Connected Vehicles: from CAN bus to IP-based In-Vehicle Networks." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20415/.

Full text

Abstract:

Il settore automotive, negli ultimi vent’anni, è stato oggetto di importanti sviluppi tecnologici, caratterizzati principalmente dall’evoluzione dei settori dell’elettronica e delle telecomunicazioni. Questo elaborato si pone come obiettivo lo studio delle tecnologie che hanno permesso l’introduzione di sistemi elettronici avanzati all’interno dei veicoli, e di come queste si siano evolute negli anni. Vengono quindi presentate le moderne idee di Connected Vehicle e di In-Vehicle Networks (IVN), nonché i principali protocolli di comunicazione che ne hanno caratterizzato l’evoluzione. Si procede poi analizzando il Controller Area Network (CAN bus), le reti veicolari IP-based ed infine il dispositivo che permette l’implementazione di reti eterogenee, l’Automotive Gateway.

APA, Harvard, Vancouver, ISO, and other styles

19

Cappelletti, Gina A. "Well-Connected| Exploring Parent Social Networks in a Gentrifying School." Thesis, University of Pennsylvania, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10601402.

Full text

Abstract:

The enrollment and engagement of middle-class families in historically low-income urban public schools can generate school improvements, including increased resources and expanded extracurricular programming. At the same time, prior research has highlighted the marginalization of low-income parents as one consequence of middle-class parent involvement. However, there is a limited understanding of the factors that contribute to parents’ central or peripheral positions within school-based parent networks in this context. Drawing on theoretical literature on social capital and social networks, this case study combines quantitative methods including social network analysis and regression-based analyses with ethnographic methods to examine the school-based social networks of kindergarten parents in a Philadelphia public school experiencing an increase in the engagement and enrollment of middle- and upper middle-class parents. I explore how school-based social networks matter to parents’ access to information, advice, and social opportunities and how these networks are shaped by parents’ informal participation in school-based events and formal participation in parent organizations.

Four key findings emerge. First, informal participation in school events is not associated with an increase in network centrality. Second, formal participation in parent organizations is related to network centrality. In particular, the networks of parents who participate in these organizations include other parents who are well-connected themselves and parents who participate in parent organizations also have greater access to network resources overall. Finally, consistent with prior research on parent involvement, findings indicate that middle- and upper-middle class parents are more likely to participate in parent organizations than low-income parents. Findings suggest that while race or class-based social position may influence parent networks in some ways, participation in parent organizations plays a greater role in the connectedness of parents’ ties and parents’ access to network resources. Implications for this research suggest the need examine practices for family and community engagement in schools and how parent organizations might be made more accessible to and inclusive of low-income parents, parents of color, and limited English-speaking parents. Furthermore, this research provides support to arguments made in prior research concerning the complexity and challenge of relying on middle-class parent involvement as a mechanism of school reform.

APA, Harvard, Vancouver, ISO, and other styles

20

Wu, Yiwei. "Connected Dominating Set Construction and Application in Wireless Sensor Networks." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/cs_diss/45.

Full text

Abstract:

Wireless sensor networks (WSNs) are now widely used in many applications. Connected Dominating Set (CDS) based routing which is one kind of hierarchical methods has received more attention to reduce routing overhead. The concept of k-connected m-dominating sets (kmCDS) is used to provide fault tolerance and routing flexibility. In this thesis, we first consider how to construct a CDS in WSNs. After that, centralized and distributed algorithms are proposed to construct a kmCDS. Moreover, we introduce some basic ideas of how to use CDS in other potential applications such as partial coverage and data dissemination in WSNs.

APA, Harvard, Vancouver, ISO, and other styles

21

He, Jing S. "Connected Dominating Set Based Topology Control in Wireless Sensor Networks." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/cs_diss/70.

Full text

Abstract:

Wireless Sensor Networks (WSNs) are now widely used for monitoring and controlling of systems where human intervention is not desirable or possible. Connected Dominating Sets (CDSs) based topology control in WSNs is one kind of hierarchical method to ensure sufficient coverage while reducing redundant connections in a relatively crowded network. Moreover, Minimum-sized Connected Dominating Set (MCDS) has become a well-known approach for constructing a Virtual Backbone (VB) to alleviate the broadcasting storm for efficient routing in WSNs extensively. However, no work considers the load-balance factor of CDSsin WSNs. In this dissertation, we first propose a new concept — the Load-Balanced CDS (LBCDS) and a new problem — the Load-Balanced Allocate Dominatee (LBAD) problem. Consequently, we propose a two-phase method to solve LBCDS and LBAD one by one and a one-phase Genetic Algorithm (GA) to solve the problems simultaneously. Secondly, since there is no performance ratio analysis in previously mentioned work, three problems are investigated and analyzed later. To be specific, the MinMax Degree Maximal Independent Set (MDMIS) problem, the Load-Balanced Virtual Backbone (LBVB) problem, and the MinMax Valid-Degree non Backbone node Allocation (MVBA) problem. Approximation algorithms and comprehensive theoretical analysis of the approximation factors are presented in the dissertation. On the other hand, in the current related literature, networks are deterministic where two nodes are assumed either connected or disconnected. In most real applications, however, there are many intermittently connected wireless links called lossy links, which only provide probabilistic connectivity. For WSNs with lossy links, we propose a Stochastic Network Model (SNM). Under this model, we measure the quality of CDSs using CDS reliability. In this dissertation, we construct an MCDS while its reliability is above a preset applicationspecified threshold, called Reliable MCDS (RMCDS). We propose a novel Genetic Algorithm (GA) with immigrant schemes called RMCDS-GA to solve the RMCDS problem. Finally, we apply the constructed LBCDS to a practical application under the realistic SNM model, namely data aggregation. To be specific, a new problem, Load-Balanced Data Aggregation Tree (LBDAT), is introduced finally. Our simulation results show that the proposed algorithms outperform the existing state-of-the-art approaches significantly.

APA, Harvard, Vancouver, ISO, and other styles

22

Hsu, Tiffany. "Data preservation in intermittently connected sensor networks via data aggregation." Thesis, California State University, Long Beach, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1527382.

Full text

Abstract:

Intermittently connected sensor networks are a subset of wireless sensor networks that have a high data volume and suffer from the problem of infrequent data offloading. When the generated data exceeds the storage capacity of the network between offloading opportunities, there must be some method of data preservation. This requires two phases: compressing the data and redistributing it. The use of data aggregation with consideration given to minimizing total energy is examined as a solution for the compression problem. Simulations of the optimal solution and an approximation heuristic are compared.

APA, Harvard, Vancouver, ISO, and other styles

23

Adulyasas, Attapol. "Connected coverage assurance for sensor scheduling in wireless sensor networks." Thesis, University of Surrey, 2015. http://epubs.surrey.ac.uk/809497/.

Full text

Abstract:

A long operational lifetime is one of ultimate goals of wireless sensor networks (WSNs) due to the limited energy resources of sensors. As sensors are often randomly deployed in vast and inaccessible areas, it is impractical to recharge or replace their energy resources such as batteries. Thus, energy efficiency is likely to be a highly important issue for the WSNs. A key approach to enhancing energy efficiency is sensor scheduling. Sensor scheduling means that in each operational round certain sensors are selected to be active, whilst others are pushed into sleep mode. However, the required quality of sensing coverage and network connectivity must be guaranteed. The former is that the entire monitored area must be fully covered at a given level called a desired coverage degree (k). Meanwhile, the latter is that every active sensor must be connected with others. Both properties together are known as the connected coverage assurance. This thesis proposes a series of sensor scheduling methods, namely 6-Triangle (6-Tri), 4-Square (4-Sqr), 3-Symmetrical area (3-Sym) and Optimum-Symmetrical area (O-Sym). The 6-Tri method uses a hexagon tessellation as a virtual partition in order to group sensors into hexagonal cells. This method activates 6 sensors from each cell. Otherwise, the 4-Sqr method uses a virtual square partition instead in order to divide the sensors into square cells. A cell consists of 4 sub-squares, within each of which a sensor is activated. Similar to the 6-Tri method, the 3-Sym method has a hexagon tessellation as its virtual partition. As only three sensors whose position is symmetrical with each other are selected in each cell, the 3-Sym method can significantly reduce the number of active sensors, compared to both the 6-Tri and 4-Sqr methods. The O-Sym method enhances the 3-Sym method by optimising coverage efficiency. It firstly investigates coverage redundancy, which is produced by the 3-Sym method, and then tries to minimise the redundancy to the desired coverage degree. This method achieves both energy efficiency and coverage efficiency, which are the main objectives of this thesis.

APA, Harvard, Vancouver, ISO, and other styles

24

張治昌 and Steven Cheung. "Packet routing on mesh-connected computers." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B3121020X.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Tatakis, Thomas Jr. "NAMER : a distributed name server for a connected UNIX environment /." Online version of thesis, 1988. http://hdl.handle.net/1850/10448.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Chaves, Cananéa Igor. "A service-based access selection algorithm for always best connected networks." Universidade Federal de Pernambuco, 2007. https://repositorio.ufpe.br/handle/123456789/2679.

Full text

Abstract:

Made available in DSpace on 2014-06-12T16:00:14Z (GMT). No. of bitstreams: 2 arquivo6094_1.pdf: 1783198 bytes, checksum: 2fbef1235c33227c30f4786356b504fc (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2007
Conselho Nacional de Desenvolvimento Científico e Tecnológico
E esperado que os v´arios sistemas de comunica¸c ao sem fio como WCDMA/HDSPA, GSM/EDGE/GPRS, WLAN e outros formar ao uma rede m´ovel multi-acesso e multiservi ¸co, capaz de oferecer servi¸cos avan¸cados de multim´ıdia. Combinado com a maior disponibilidade de terminais capazes de se comunicar usando mais de uma tecnologia, os usu´arios desse sistema obter ao vantagens ao usar a technologia mais apropriada para um determinado servi¸co. Infelizmente, mais op¸c oes podem trazer mais complexidade se isso significar mais configura¸c oes manuais para o usu´ario, tornando a experi encia de uso pior. Uma forma autom´atica de selecionar a rede mais apropriada seria uma solu¸c ao pr´atica interessante para aliviar a necessidade de configura¸c oes por parte do usu´ario. O conceito de redes Always Best Connected (ABC) define que dispositivos devem estar sempre online, conectados atrav´es das tecnologias de comunica¸c ao dispon´ıveis que s ao capazes de atender os requisitos dos servi¸cos dos usu´arios e tamb´em respeitar os requisitos de funcionamento das operadoras das redes. A realiza¸c ao desse conceito implica em tratar o conjunto de tecnologias existentes como uma ´unica rede com caracter´ısticas heterg eneas que pode ser explorada de acordo com a demanda das diversas classes de servi¸co. A utiliza¸c ao de um Gerenciador Commum de Recursos de Radio (GCRR) ´e uma forma de atingir esse objetivo, pois ele teria acesso aos status das diversas redes e poderia decidir qual a melhor a¸c ao a ser tomada. Atualmente, existem algumas solu¸c oes limitadas para sele¸c ao autom´atica de redes, principalmente porque a complexidade da decis ao a ser tomada aumenta com o n´umero de classes de servi¸cos e tecnologias supportadas. Outra limita¸c ao ´e que os algoritmos utilizados s ao tipicamente offline, o que significa que algum conhecimento sobre o tr´afego deve ser assumido, resultando em solu¸c oes n ao ´otimas. Este trabalho apresenta uma heur´ıstica para sele¸c ao de acesso online em redes ABC que ´e quase-´otima independentemente do n´umero de tecnologias de acesso suportadas e no que diz respeito a utiliza¸c ao de recursos, taxas de atendimento e rejei¸c ao de servi¸cos. O algoritmo ´e chamado de LessDamage e foi desenvolvido para funcionar como uma heur´ıstica de binpacking, onde os objetos a serem empacotados s ao as aplica¸c oes e as caixas s ao as tecnologias suportadas. A an´alise de desempenho mostrou que a solu¸c ao proposta tem desempenho superior ao de algoritmos cl´assicos de binpacking e a sua compara¸c ao com um algoritmo ´otimo offline mostrou que seu desempenho ´e muito bom. Uma poss´ıvel dire¸c ao para tornar o algoritmo escal´avel tanto com o n´umero de classes de servi¸cos quanto com o n´umero de technologias tamb´em ´e apresentada

APA, Harvard, Vancouver, ISO, and other styles

27

Sevgi, Cuneyt. "Network Dimensioning In Randomly Deployed Wireless Sensor Networks." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12611213/index.pdf.

Full text

Abstract:

In this study, we considered a heterogeneous, clustered WSN, which consists of two types of nodes (clusterheads and sensor nodes) deployed randomly over a sensing field. We investigated two cases based on how clusterheads can reach the sink: direct and multi-hop communication cases. Network dimensioning problems in randomly deployed WSNs are among the most challenging ones as the attributes of these networks are mostly non-deterministic. We focused on a number of network dimensioning problems based on the connected coverage concept, which is the degree of coverage achieved by only the connected devices. To evaluate connected coverage, we introduced the term cluster size, which is the expected value of the area covered by a clusterhead together with sensor nodes connected to it. We derived formulas for the cluster size and validated them by computer simulations. By using the cluster size formulas, we proposed a method to dimension a WSN for given targeted connected coverage. Furthermore, we formulated cost optimization problems for direct and multi-hop communication cases. These formulations utilize not only cluster size formulas but also the well-connectivity concept. We suggested some search heuristics to solve these optimization problems. Additionally, we justified that, in practical cases, node heterogeneity can provide lower cost solutions. We also investigated the lifetime of WSNs and for mulated a cost optimization problem with connected coverage and lifetime constraints. By solving this optimization problem, one can determine the number of nodes of each type and the initial energies of each type of node that leads to lowest cost solution while satisfying the minimum connected coverage and minimum lifetime requirements.

APA, Harvard, Vancouver, ISO, and other styles

28

Bani, Mohammad Saad O. "Efficient processor allocation strategies for mesh-connected multicomputers." Connect to e-thesis, 2008. http://theses.gla.ac.uk/293/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Twining, Erika. "Voltage compensation in weak distribution networks using shunt connected voltage source converters." Monash University, Dept. of Electrical and Computer Systems Engineering, 2004. http://arrow.monash.edu.au/hdl/1959.1/9701.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Black, Alison Michelle. "Resiliency Networks| Bridging Multiple Worlds of Military-Connected Adolescents in Civilian Schools." Thesis, University of California, San Diego, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10123613.

Full text

Abstract:

A majority of the nation’s military-connected dependents attend civilian public schools, yet there are pervasive inconsistencies in support programs and policies across schools (De Pedro, Astor, Gilreath, Benbenishty, & Esqueda, 2013). High mobility rates present several challenges to children of military Service members, such as learning gaps, social and emotional difficulties, and challenges forming relationships with peers and school personnel (Astor, Jacobson, & Benbenishty, 2012). This study examined how military-connected adolescents bridged their multiple military and civilian worlds in the school context. The theoretical foundations of the study included the Bridging Multiple Worlds (BMW) (Cooper, 2014) model and Social Network theory. The BMW design investigated military-connected adolescents’ perceived challenges and strengths of belonging to a military cultural community along with how they accessed resources for overcoming those challenges. Social Capital and Social Network theory situated developmental processes in a socialized context highlighting how interpersonal relationships shape development (Bourdieu, 1986; Daly, Moolenaar, Bolivar, & Burke, 2010). Focus groups revealed participants faced many of the typical challenges facing military-connected youth. They also perceived many of those challenges as having promoted positive developmental outcomes: social skills, resilience, and adaptability. Social networks, friendship networks and support networks, played an important role in overcoming the challenges of navigating their military and civilian worlds. Findings indicated differences in academic outcomes (GPA) between military and civilian participants, as well as between enlisted and officer participants. Findings also indicated different social network patterns between enlisted participants and officer participants. The rich history of military support within the local community and school environment may have influenced how military participants integrated into the whole eighth-grade friendship network. This study sought to fill the research gap by accurately representing the social and educational needs and circumstances of military-connected adolescents in a military-dense civilian middle school and to help educators create highly supportive environments for military-connected adolescents in civilian schools.

APA, Harvard, Vancouver, ISO, and other styles

31

Huang, Jyh-How. "Occasionally connected wireless sensor networks for search and rescue and wildlife monitoring." Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3337106.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Kuiper, Erik. "Geographic Routing in Intermittently-connected Mobile Ad Hoc Networks : Algorithms and Performance Models." Doctoral thesis, Linköpings universitet, RTSLAB - Laboratoriet för realtidssystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-72792.

Full text

Abstract:

Communication is a key enabler for cooperation. Thus to support efficient communication humanity has continuously strived to improve the communication infrastructure. This infrastructure has evolved from heralds and ridden couriers to a digital telecommunication infrastructures based on electrical wires, optical fibers and radio links. While the telecommunication infrastructure efficiently transports information all over the world, there are situations when it is not available or operational. In many military operations, and disaster areas, one cannot rely on the telecommunication infrastructure to support communication since it is either broken, or does not exist. To provide communication capability in its absence, ad hoc networking technology can be used to provide a dynamic peer-based communication mechanism. In this thesis we study geographic routing in intermittently connected mobile ad hoc networks (IC-MANETs). For routing in IC-MANETs we have developed a beacon-less delay-tolerant geographic routing protocol named LAROD (location aware routing for delay-tolerant networks) and the delay-tolerant location service LoDiS (location dissemination service). To be able to evaluate these protocols in a realistic environment we have used a military reconnaissance mission where unmanned aerial vehicles employ distributed coordination of their monitoring using pheromones. To be able to predict routing performance more efficiently than by the use of simulation, we have developed a mathematical framework that efficiently can predict the routing performance of LAROD-LoDiS. This framework, the forward-wait framework, provides a relationship between delivery probability, distance, and delivery time. Provided with scenario specific data the forward-wait framework can predict the expected scenario packet delivery ratio. LAROD-LoDiS has been evaluated in the network simulator ns-2 against Spray and Wait, a leading delay-tolerant routing protocol, and shown to have a competitive edge, both in terms of delivery ratio and overhead. Our evaluations also confirm that the routing performance is heavily influenced by the mobility pattern. This fact stresses the need for representative mobility models when routing protocols are evaluated.

APA, Harvard, Vancouver, ISO, and other styles

33

Garcia, del Molino Luis Carlos. "Non-hermitian random matrices and applications to randomly connected firing rate neuronal networks." Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCC167.

Full text

Abstract:

On étudie l'impacte des propriétés statistiques des matrices de connectivité sur la dynamique des réseaux de neurones. Cette étude se fait à travers de l'analyse des propriétés spectrales de matrices aléatoires
We study the impact of the statistical properties of connectivity matrices on the dynamics of neuronal networks. This study is done by analyzing the spectral properties of random matrices

APA, Harvard, Vancouver, ISO, and other styles

34

Janapala, Srinivas. "Maximizing connected coverage via controlled actor relocation in Wireless Sensor and Actor Networks /." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1597619381&sid=12&Fmt=2&clientId=1509&RQT=309&VName=PQD.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Ray, Aaron Parker. "Planning Connected: Using Online Social Networks to Improve Knowledge about Places and Communities." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/580.

Full text

Abstract:

The advent of Social Networking Systems (SNS) has introduced new possibilities for planners to refine and extend conventional engagement and data-gathering techniques by leveraging user-contributed, spatially-referenced content freely available online. This study examines the use of SNS content as community input, complementing input gathered through traditional participatory processes such as workshops, public comment hearings, and charrettes. Four case studies of recent community planning projects in the United States are analyzed, comparing the data gathered from traditional participatory processes with available SNS content related to each project study area, to determine to what extent the inclusion of SNS data would improve the overall data- gathering efforts of these projects. Three significant findings emerge from this analysis: (i) that SNS data analysis can positively complement data gathered from traditional participatory processes, (ii) that although SNS data analysis can provide useful data to planners, it is not a direct replacement for conventional engagement techniques, and (iii) that SNS data analysis is most effective for projects in neighborhoods with a well- defined identity. The study also examines the characteristics of effective SNS data analysis integration and discusses broader implications for planning practitioners and additional research needed.

APA, Harvard, Vancouver, ISO, and other styles

36

Xue, Xin. "Health monitoring of drive connected three-phase induction motors from wired towards wireless sensor networks /." Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://proquest.umi.com/pqdweb?index=0&did=1899497101&SrchMode=2&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1269019645&clientId=48051.

Full text

Abstract:

Thesis (Ph. D.)--University of California, Riverside, 2009.
Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 20, 2010). Includes bibliographical references. Also issued in print.

APA, Harvard, Vancouver, ISO, and other styles

37

Hume, Thomas. "Practical and theoretical approaches for module analysis of protein-protein interaction networks." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0006/document.

Full text

Abstract:

Un des principaux défis de la bioinformatique moderne est de saisir le sens des données biologiques en constante croissance. Il est prépondérant de trouver de bons modèles pour toutes ces données, modèles qui servent à la fois à expliquer les données et à produire des réponses aux questions biologiques sous-jacentes. Une des nombreuses difficultés d’une telle approche est la grande variété dans les types des données manipulées. La biologie computationnelle moderne propose des approches qui combinent ces types de données dans des techniques dites intégratives. Cette thèse contribue au problème de l’identification de module biologique en intégrant les informations de conservation dans les modèles modernes d’identification d’ensemble de protéines. Nous introduisons un modèle pour la détection de modules connexes actifs et conservés, c’est-à-dire des modules connexes dont une majorité d’éléments sont similaires entre deux espèces. Nous présentons une formulation de notre modèle sous forme de programmation linéaire en nombres entiers, et proposons un algorithme branch-and-cut qui résout le modèle à l’optimalité en temps raisonnable. Nous appliquons notre modèle sur des données de différentiation cellulaire, à savoir les cellules Th0 en Th17 pour l’humain et la sourie. Nous analysons également notre modèle du point du vue de la complexité algorithmique, et fournissons des résultats pour le cas général ainsi que des cas spéciaux
One of the major challenge for modern bioinformatics is making sense of the ever increasing size of biological data. Finding good models for all this data, models that can both explain the data and provide insight into biological questions, is paramount. One of the many difficulties of such path is the variety in the types of data. Modern computational biology approaches combine these many data into integrative approaches, that combine the knowledge inside the data in the hope to extract higher level information. This thesis contribute to the biological module identification problem by integrating conservation information with modern models of modular detection of protein sets. We introduce a model for the detection of conserved active connected modules, that is connected modules that are conversed across two species. These active connected modules are similar in sequence composition between the two species. We present a mixed-integer linear programming formulation of our model, and propose a branch-and-cut algorithm to solve to provable optimality in reasonable run time. We apply our model to cell line differentiation data, namely Th0 into Th17 for both human and mouse. We also analyse the model from a complexity standpoint, and provide general as well as special cases complexity results

APA, Harvard, Vancouver, ISO, and other styles

38

Chbib, Fadlallah. "Enhanced Cross Layer and Secure Architecture for Connected Vehicles." Thesis, Troyes, 2021. http://www.theses.fr/2021TROY0038.

Full text

Abstract:

Les réseaux ad hoc de véhicules (VANET), sont déployés pour minimiser le risque d'accidents de la route et améliorer le confort des passagers. Cette thèse traite le problème de l'abandon et du retard des paquets dans les VANET en réduisant le temps d'échange des données et en améliorant le taux de livraison des paquets. Elle traite également la problématique de protection de l’architecture véhiculaire. D’abord, nous proposons une méthode pour éviter la congestion sur le canal de contrôle afin de garantir le transfert en temps réel et la fiabilité des messages de sécurité urgents. En outre, nous utilisons un réseau de neurones pour réduire le temps d'échange des données de sécurité. Deuxièmement, nous proposons deux protocoles de routage basés sur le rapport Signal/Interférence (SIR). Dans les deux protocoles, notre objectif est de maximiser le SIR global entre la source et la destination afin de sélectionner le chemin optimal. Dans le premier protocole, nous évaluons le niveau de SIR, tandis que dans le second, nous utilisons une chaîne de Markov pour prédire le niveau de SIR. Enfin, nous protégeons ces protocoles contre diverses attaques grâce à trois algorithmes anti-attaque. Dans le premier algorithme, nous créons une variable clé-valeur pour détecter la fabrication de l'adresse source au niveau du nœud intermédiaire. Dans le deuxième, nous créons un tampon et le vérifions périodiquement afin d'attraper le nœud malveillant dans le champ de destination. Enfin, le but du dernier algorithme est de découvrir l’attaque au niveau du SIR
Vehicular Ad hoc NETworks, known as VANETs, are deployed to minimize the risk of road accidents as well as to improve passengers comfort. This thesis deals with the problem of dropping and delaying packets in VANETs by reducing the time of exchanging data, improving the packet delivery ratio, as well as securing the vehicular architecture. First, we propose a novel method to avoid the congestion on the control channel in order to guarantee the real time transfer and the reliability of urgent safety messages. In addition, we extend the proposed method by using a neural network with various parameters such as priority of the message, sensitivity of road, type of vehicle and buffer state to reduce the time of exchanging safety data. Second, we propose two routing protocols based on signal to interference ratio (SIR). Our target in both is to maximize the overall SIR between source and destination with the aim to select the optimal path. In the first one, we evaluate the SIR level, while in the second, we use a Markov chain model to predict the SIR level. Finally, we protect these protocols from various attacks through three anti-attack algorithms. In the first algorithm, we create a key-value variable to detect the fabrication of the source address at the intermediate node. In the second one, we create a buffer and check it periodically in order to catch out the malicious node occurring at the destination field. In the last one, we discover the attack at the SIR level

APA, Harvard, Vancouver, ISO, and other styles

39

Li, Jiakai. "AI-WSN: Adaptive and Intelligent Wireless Sensor Networks." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1341258416.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Taylor, Michael. "Exact and approximate epidemic models on networks : theory and applications." Thesis, University of Sussex, 2013. http://sro.sussex.ac.uk/id/eprint/45258/.

Full text

Abstract:

This thesis is concerned with modelling the spread of diseases amongst host populations and the epidemics that result from this process. We are primarily interested in how networks can be used to model the various heterogeneities observable in real-world populations. Firstly, we start with the full system of Kolmogorov/master equations for a simple Susceptible-Infected-Susceptible (SIS) type epidemic on an arbitrary contact network. From this general framework, we rigorously derive sets of ODEs that describe the exact dynamics of the expected number of individuals and pairs of individuals. We proceed to use moment closure techniques to close these hierarchical systems of ODEs, by approximating higher order moments in terms of lower order moments. We prove that the simple first order mean-field approximation becomes exact in the limit of a large, fully-connected network. We then investigate how well two different pairwise approximations capture the topological features of theoretical networks generated using different algorithms. We then introduce the effective degree modelling framework and propose a model for SIS epidemics on dynamic contact networks by accounting for random link activation and deletion. We show that results from the resulting set of ODEs agrees well with results from stochastic simulations, both in describing the evolution of the network and the disease. Furthermore, we derive an analytic calculation of the stability of the disease-free steady state and explore the validity of such a measure in the context of a dynamically evolving contact network. Finally, we move on to derive a system of ODEs that describes the interacting dynamics of a disease and information relating to the disease. We allow individuals to become responsive in light of received information and, thus, reduce the rate at which they become infected. We consider the effectiveness of different routes of information transmission (such as peer-to-peer communication or mass media campaigns) in slowing or preventing the spread of a disease. Finally, we use a range of modelling techniques to investigate the spread of disease within sheep flocks. We use field data to construct weighted contact networks for flocks of sheep to account for seasonal changes of the flock structure as lambs are born and eventually become weaned. We construct a range of network and ODE models that are designed to investigate the effect of link-weight heterogeneity on the spread of disease.

APA, Harvard, Vancouver, ISO, and other styles

41

Matlokotsi, Tlhoriso. "Power quality enhancement in electricity networks using grid-connected solar and wind based DGs." Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25437.

Full text

Abstract:

The integration of DG into utility networks has significantly increased over the past years primarily as a result of growing energy demand, coupled with the environmental impacts posed by conventional fossil fuel-based power generation. The prominent DG technologies which are capable of meeting bulk energy demands and are clean energy sources are wind and solar energy sources. The resources for solar and wind based DG are available in abundance in most geographical locations in South Africa and the rest of Africa. Through the Renewable Energy Independent Power Producer Procurement Programme (REIPPPP) introduced by the South African government in 2011, 3 920 MW of renewable energy has been procured to date. Out of this, solar and wind energy constitute 2 200 MW and 960 MW, respectively. Grid integration of solar and wind-based intermittent DGs may however pose negative impacts on the quality of power supplied by the utility network. Some of the detrimental impacts of DG include voltage fluctuations, flicker, etc. which are in general categorised as power quality (PQ) problems. The proper planning of DG integration is required to mitigate the negative impacts they pose on system's PQ to ensure that the performance of the utility network is enhanced in terms of the overall PQ improvement of the system. This dissertation reviews general PQ problems in utility networks with DG integration and whether poor planning of DG integration affects PQ negatively. The work emphasizes on the impacts of grid integration of wind and solar PV sources on power quality. It investigates the manner in which wind and solar energy systems differ in their impacts and capacity to improve PQ of the network in terms of a number of factors such as point of integration and capacity of DG, type of DG, network loading, etc. The role of grid-integrated DG in PQ improvement in electricity network is also investigated by exploring different PQ improvement techniques. The networks considered for the grid integration of DG for PQ improvement in this work are the IEEE 9-bus sub-transmission network at the nominal voltage of 230kV and the IEEE 33-bus distribution network at the nominal voltage of 12 kV. The aspects essential for facilitating proper planning of DG integration for PQ improvement and total loss reduction are investigated and the comparative analysis is made between grid integration of wind and solar PV based DGs. The simulations of different case studies in this work are done using DIgSILENT PowerFactory version 14.1 as well as coding in MATLAB. The cases studies conducted are aimed at facilitating the proper planning of grid integration of wind and solar PV-based DGs by comparing their PQ improvement capabilities under different scenarios. First the investigation of how their location and capacity affect the network voltage profiles and active power losses is conducted. Their ability to improve the system's PQ is also studied by observing PQ improvement strategies such as voltage control, installation of energy storage and the optimal placement of DGs under different scenarios. In order to account for the weakness of most South African utility grids, PQ improvement in weak networks with DG integration is also studied by investigating how DG integration in networks with different grid strengths affect the system's PQ. The results provide an understanding of the role of grid integration of wind and solar based DGs on PQ which is useful in the planning of grid integration of RE, particularly in South African electricity networks. The results revealed that the location and capacity of integrated DGs indeed affect the quality of power as well as active power losses in the grid. It is also established that a significant improvement in network's PQ and line loss reduction can be achieved in networks with wind and solar integration. The results however indicated that wind and solar PV based DGs differ in their impacts and capacity to improve the quality of power in the network. Furthermore, the results revealed that wind and solar plants integration into weak utility grids may pose adverse impacts on the system's PQ. It was however established that including reactive power control devices such as STATCOM and SVC at the PCC can successfully improve the system's PQ and enable grid code compliance in electricity networks with DG integration.

APA, Harvard, Vancouver, ISO, and other styles

42

Peterson, Gretchen. "Perceptions of fairness in social exchange: A comparison of negatively and positively connected networks." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/284288.

Full text

Abstract:

Research within the exchange tradition has focused largely on the effects of network structure (in terms of the positioning of actors within a network) on the distribution of power. While network structure in this limited sense has received considerable attention in the literature, one aspect of network structure, which has remained largely unexplored, is the type of network connection. Emerson (1972) identified two types of network connection: negative connections and positive connections. In a negatively connected network, actors must compete with one another for valued exchanges and thus, these networks are inherently competitive. On the other hand, positively connected networks have the potential to be cooperative since exchange in one relation in the network facilitates exchange in a connected relation. In this dissertation, I argue that the type of network connection affects our expectations for the behavior of our exchange partners and thus affects our evaluations of the fairness of those partners. In addition to network connection, I also examine the role that information about a peripheral network member (one who is not a direct exchange partner) plays in affecting evaluations of the fairness of a direct exchange partner. Thus, this dissertation focuses on this concept of network connection and unites exchange and justice theories by examining the effects of network connection on perceptions of fairness. The research design involves a 2 x 2 x 2 factorial experiment crossing network connection (positive or negative), equality of an exchange partner's behavior (equal or unequal behavior) and information about the behavior of a peripheral network member (full information about this actor's behavior or no information). While the hypotheses were not supported in this experiment, some of the results concerning the underlying mechanisms indicate that network connection remains an important avenue for further research. Several possibilities for the lack of support for the hypotheses are discussed as well as the possible avenues for future research.

APA, Harvard, Vancouver, ISO, and other styles

43

Cho, Jinyoun. "Efficient safety message dissemination methods in vehicular adhoc networks." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53390.

Full text

Abstract:

The methods for efficient safety message dissemination in VANETs were proposed. First, the method for using multi-channel was proposed. Using the proposed multi-channel method (divide-and-deliver algorithm), the safety message was delivered to the target device with less delay compared to the traditional single-channel method. This method showed resilient performance even in poor wireless channels compared to the single-channel method. Second, to improve low reliability in low vehicle density situations, the enhanced divide-and-deliver algorithm was proposed. The network coding was a key technique to the enhancement. For the efficient use of network coding, rigorous analysis was conducted and an algorithm was proposed to change the number of network coding packets adaptively by the vehicle densities. Finally, the method for delivering safety messages to multi-direction was proposed. This multi-vehicle selection broadcast (MSB) algorithm avoided the collision between multiple rebroadcasts among vehicles and removed unnecessary packets by using backoff slots. The contributions of this research include reducing delay and increasing reliability for the dissemination of safety messages.

APA, Harvard, Vancouver, ISO, and other styles

44

Cao, Guangtong. "Distributed services for mobile ad hoc networks." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2541.

Full text

Abstract:

A mobile ad hoc network consists of certain nodes that communicate only through wireless medium and can move arbitrarily. The key feature of a mobile ad hoc network is the mobility of the nodes. Because of the mobility, communication links form and disappear as nodes come into and go out of each other's communica- tion range. Mobile ad hoc networks are particularly useful in situations like disaster recovery and search, military operations, etc. Research on mobile ad hoc networks has drawn a huge amount of attention recently. The main challenges for mobile ad hoc networks are the sparse resources and frequent mobility. Most of the research work has been focused on the MAC and routing layer. In this work, we focus on distributed services for mobile ad hoc networks. These services will provide some fundamental functions in developing various applications for mobile ad hoc networks. In particular, we focus on the clock synchronization, connected dominating set, and k-mutual exclusion problems in mobile ad hoc networks.

APA, Harvard, Vancouver, ISO, and other styles

45

Danzfuss, Theodor Werner. "The technology of casually connected collaboration." Diss., Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-11232009-181958/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Vergara, Alonso Ekhiotz Jon. "Implementation of a manycast protocol for intermittently connected mobile ad hoc networks in disaster areas." Thesis, Linköpings universitet, RTSLAB - Laboratoriet för realtidssystem, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-58603.

Full text

Abstract:

Nowadays, the use of mobile phones and other wireless devices has become an indispensable part of daily life. However, the focus of wireless communication is on infrastructure-based networks, making them prone to service outage if for any reason the infrastructure is overloaded or there is no network coverage. This is the case in a disaster area, where the infrastructure that supports the communication may be destroyed or could become useless. Different approaches to complement the exchange of information in these scenarios are emerging as research results. This thesis concerns Random-Walk Gossip (RWG), which is a protocol to disseminate information in disaster areas. RWG is a many-cast protocol for intermittently connected mobile ad hoc networks. The more people can communicate, the more chances of success there are. Therefore, it is useful to investigate the possibility of implementing such protocols on commodity devices. Since Symbian is currently the most widespread mobile phone operating system, this master's thesis presents the implementation of the protocol in that platform. The protocol is also implemented in Linux and Mac OS X in order to provide heterogeneity. Finally, some aspects of the performance of the protocol in different devices are analyzed, studying the CPU load, memory consumption, radio range, energy consumption and response time of different devices using the protocol. The studies show that the use of the RWG protocol in both laptops and handheld devices is viable.

APA, Harvard, Vancouver, ISO, and other styles

47

Isaksson, Lennart. "Seamless communications : seamless handover between wireless and cellular networks with focus on always best connected /." Karlskrona : Department of Telecommunications, School of Engineering, Blekinge Institute of Technology, 2007. http://www.bth.se/fou/Forskinfo.nsf/allfirst2/81f841f7e9b75346c12572ab0071ddb4?OpenDocument.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Leon, Calvo Jose Angel [Verfasser]. "5G Heterogeneous Networks for Connected Vehicles : A Cooperative Multi-Layer Approach / Jose Angel Leon Calvo." Aachen : Shaker, 2018. http://d-nb.info/1188550233/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Li, Yi Yuan, and 李逸元. "Ring-connected interconnection networks." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/07442430003935229392.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Kempe, Gregory. "Communication in intermittently-connected networks." Thesis, 2005. http://hdl.handle.net/2429/16606.

Full text

Abstract:

Communication in the face of intermittent, short-lived and possibly unreliable connectivity can be difficult when relying solely on Internet protocols, such as IP and TCP, which have an implicit assumption of well-connectedness. Furthermore, use of these protocols is impossible when there is no fully connected end-to-end path between hosts. We present Euonym, an architecture that uses a layer of persistent names to identify hosts, networks and services, and allows arbitrary intermediate helper hosts to be interposed between endpoints on-the-fly. These helper hosts can provide routing, buffering and other support services to help relieve reliance on end-to-end paths. They can be placed to take advantage of intermittent connectivity when and as it arises and be used to supplement connectivity with untraditional networking and transport mechanisms, such as data mules and the postal network, without any additional support at the end hosts. We show that simple disconnection tolerance and use of intermediate hosts facilitates communication and promotes connectivity in intermittently-connected networks.
Science, Faculty of
Computer Science, Department of
Graduate

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Connected networks'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles