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1
Tam, Wing-yan, e 譚泳茵. "Quality of service routing with path information aggregation". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B36782956.
Testo completo
2
Saraireh, Mohammad Suleiman Abdul-Qader. "Medium access control mechanisms for quality of service in wireless computer networks". Thesis, Sheffield Hallam University, 2006. http://shura.shu.ac.uk/20325/.
Testo completoAbstract (sommario):
The fast growth and development of wireless computer networks and multimedia applications means it is essential that these applications can be transmitted over the standard IEEE 802.11 Medium Access Control (MAC) protocol with high Quality of Service (QoS). The lack of QoS in the standard IEEE 802.11 Distributed Coordination Function (DCF) results in applications with considerably different QoS requirements receiving similar network services. This means, the performance of time-sensitive applications with stringent delay, jitter, and packet loss requirements will not be met. Even time-insensitive applications will be treated unfairly because access to the medium is on a random basis. Therefore, the main aims of this thesis are: (i) to investigate the limitations and performance of the IEEE 802.11 DCF, (ii) to develop a comprehensive solution that provides effective and efficient QoS provisioning in IEEE 802.11 DCF scheme in a fair, scalable, and robust manner. The latter is achieved by developing novel MAC mechanisms for providing QoS in the IEEE 802.11 DCF for multimedia transmission. The scarcity of channel capacity, unfairness and hidden terminal problems, multiple hops, and other conditions and parameters that affect QoS in a wireless network are issues which require in depth investigations and analysis. In this thesis, extensive investigations using the network simulator 2 (NS-2) package were carried out to examine the impact of these issues on the main QoS parameters (throughput, delay, jitter, packet loss and collision). The findings revealed that the IEEE 802.11 DCF protocol performed inadequately when transmitting various applications due to the limitations inherent in its operation. The performance of the IEEE 802.11 DCF protocol was also investigated by studying the impact of varying the values of minimum Contention Window (CW[min]) and the Distributed Inter Frame Space (DIFS). The study shows that inappropriate values of CW[min] and DIFS resulted in significant network performance degradations and demonstrated that it was important to select an appropriate set of MAC protocol transmission parameters in order to provide improved QoS.Artificial Intelligence (AI) techniques using fuzzy logic and Genetic Algorithms (GAs) for assessing and optimising MAC protocol transmission parameters were developed and their effectiveness evaluated. The study confirmed that the application of AI techniques significantly improved the QoS for audio and video applications by more than 50% and fairly shared the channel access among the contending stations as compared to the standard IEEE 802.11 DCF scheme. Ratio based and Collision Rate Variation (CRV) schemes were developed to dynamically adjust the CW and DIFS values according to the current and past network conditions. Using these schemes significant improvements with service differentiation were achieved in an Independent Basic Service Set (IBSS). A queue status monitoring technique was devised for the intermediate stations. This provided QoS differentiation at the MAC layer for multi-hop networks. Autoregressive (AR) models that accurately predicted the network parameters were also developed. These enabled the MAC protocol transmission parameters to be adjusted in an improved manner. Using these models, average QoS was improved by more than 60%; average delay, packet loss and collision were reduced by more than 50% compared to IEEE 802.11 DCF scheme. This led to the development of novel MAC mechanisms to provide QoS in IEEE 802.11 MAC protocol. The mechanisms support multiple QoS metrics and consider traffic history and predict future network conditions. The schemes also are characterised by the simplicity, robustness, and ease of implementation. The contribution of this thesis is the development of a comprehensive solution to provide effective and efficient QoS differentiation in IEEE 802.11 DCF scheme for multimedia transmission in a distributed, fair, scalable, and robust manner. Furthermore, through the use of these approaches, the findings of this study provide a framework that also contributes to the knowledge concerning the QoS over the IEEE 802.11 MAC protocol.
3
Chang, Xiaolin. "On improving Internet quality of service using a control theoretic approach /". View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?COMP%202005%20CHANG.
Testo completo
4
Foulkes, Philip James. "An investigation into the control of audio streaming across networks having diverse quality of service mechanisms". Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1004865.
Testo completoAbstract (sommario):
The transmission of realtime audio data across digital networks is subject to strict quality of service requirements. These networks need to be able to guarantee network resources (e.g., bandwidth), ensure timely and deterministic data delivery, and provide time synchronisation mechanisms to ensure successful transmission of this data. Two open standards-based networking technologies, namely IEEE 1394 and the recently standardised Ethernet AVB, provide distinct methods for achieving these goals. Audio devices that are compatible with IEEE 1394 networks exist, and audio devices that are compatible with Ethernet AVB networks are starting to come onto the market. There is a need for mechanisms to provide compatibility between the audio devices that reside on these disparate networks such that existing IEEE 1394 audio devices are able to communicate with Ethernet AVB audio devices, and vice versa. The audio devices that reside on these networks may be remotely controlled by a diverse set of incompatible command and control protocols. It is desirable to have a common network-neutral method of control over the various parameters of the devices that reside on these networks. As part of this study, two Ethernet AVB systems were developed. One system acts as an Ethernet AVB audio endpoint device and another system acts as an audio gateway between IEEE 1394 and Ethernet AVB networks. These systems, along with existing IEEE 1394 audio devices, were used to demonstrate the ability to transfer audio data between the networking technologies. Each of the devices is remotely controllable via a network neutral command and control protocol, XFN. The IEEE 1394 and Ethernet AVB devices are used to demonstrate the use of the XFN protocol to allow for network neutral connection management to take place between IEEE 1394 and Ethernet AVB networks. User control over these diverse devices is achieved via the use of a graphical patchbay application, which aims to provide a consistent user interface to a diverse range of devices.
5
Blanpain, Yannick. "A scalable and deployable approach for achieving fair rate allocation in high speed networks". Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/14868.
Testo completo
6
Li, Wei. "Artificial neural networks for quality control of seam pucker on textiles". Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41508312.
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7
Li, Wei, e 李巍. "Artificial neural networks for quality control of seam pucker on textiles". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41508312.
Testo completo
8
Zafer, Murtaza Abbasali 1979. "Dynamic rate-control and scheduling algorithms for quality-of-service in wireless networks". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42241.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (p. 195-202).
Rapid growth of the Internet and multimedia applications, combined with an increasingly ubiquitous deployment of wireless systems, has created a huge demand for providing enhanced data services over wireless networks. Invariably, meeting the quality-of-service requirements for such services translates into stricter packet-delay and throughput constraints on communication. In addition, wireless systems have stringent limitations on resources which necessitates that these must be utilized in the most efficient manner. In this thesis, we develop dynamic rate-control and scheduling algorithms to meet quality-of-service requirements on data while making efficient utilization of resources. Ideas from Network Calculus theory, Continuous-time Stochastic Optimal Control and Convex Optimization are utilized to obtain a theoretical understanding of the problems considered, and to develop various insights from the analysis. We, first, address energy-efficient transmission of deadline-constrained data over wire-less fading channels. In this setup, a transmitter with controllable transmission rate is considered, and the objective is to obtain a rate-control policy for transmitting deadline- constrained data with minimum total energy expenditure. Towards this end, a deterministic model is first considered and the optimal policy is obtained graphically using a novel cumulative curves methodology. We, then, consider stochastic channel fading and introduce the canonical problem of transmitting B units of data by deadline T over a Markov fading channel. This problem is referred to as the "BT-problem" and its optimal solution is obtained using techniques from stochastic control theory.
(cont.) Among various extensions, specific setups involving variable deadlines on the data packets, known arrivals and a Poisson arrival process are considered. Using a graphical approach, transmission policies for these cases are obtained through a natural extension of the results obtained earlier. In the latter part of the thesis, a multi-user downlink model is considered which consists of a single transmitter serving multiple mobile users. Here, the quality-of-service requirement is to provide guaranteed average throughput to a certain class of users, and the objective is to obtain a multi-user scheduling policy that achieves this using the minimum number of time-slots. Based on a geometric approach we obtain the optimal policy for a general fading scenario, and, further specialize it to the case of symmetric Rayleigh fading to obtain closed-form relationships among the various performance metrics.
by Murtaza Abbasali Zafer.
Ph.D.
9
Rakotoarivelo, Thierry Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Distributed discovery and management of alternate internet paths with enhanced quality of service". Awarded by:University of New South Wales. School of Electrical Engineering and Telecommunications, 2006. http://handle.unsw.edu.au/1959.4/27316.
Testo completoAbstract (sommario):
The convergence of recent technology advances opens the way to new ubiquitous environments, where network-enabled devices collectively form invisible pervasive computing and networking environments around the users. These users increasingly require extensive applications and capabilities from these devices. Recent approaches propose that cooperating service providers, at the edge of the network, offer these required capabilities (i.e services), instead of having them directly provided by the devices. Thus, the network evolves from a plain communication medium into an endless source of services. Such a service, namely an overlay application, is composed of multiple distributed application elements, which cooperate via a dynamic communication mesh, namely an overlay association. The Quality of Service (QoS) perceived by the users of an overlay application greatly depends on the QoS on the communication paths of the corresponding overlay association. This thesis asserts and shows that it is possible to provide QoS to an overlay application by using alternate Internet paths resulting from the compositions of independent consecutive paths. Moreover, this thesis also demonstrates that it is possible to discover, select and compose these independent paths in a distributed manner within an community comprising a limited large number of autonomous cooperating peers, such as the fore-mentioned service providers. Thus, the main contributions of this thesis are i) a comprehensive description and QoS characteristic analysis of these composite alternate paths, and ii) an original architecture, termed SPAD (Super-Peer based Alternate path Discovery), which allows the discovery and selection of these alternate paths in a distributed manner. SPAD is a fully distributed system with no single point of failure, which can be easily and incrementally deployed on the current Internet. It empowers the end-users at the edge of the network, allowing them to directly discover and utilize alternate paths.
10
Benfattoum, Youghourta, e Youghourta Benfattoum. "Network coding for quality of service in wireless multi-hop networks". Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00763375.
Testo completoAbstract (sommario):
In this thesis we deal with the application of Network Coding to guarantee the Quality of Service (QoS) for wireless multi-hop networks. Since the medium is shared, wireless networks suffer from the negative interference impact on the bandwidth. It is thus interesting to propose a Network Coding based approach that takes into account this interference during the routing process. In this context, we first propose an algorithm minimizing the interference impact for unicast flows while respecting their required bandwidth. Then, we combine it with Network Coding to increase the number of admitted flows and with Topology Control to still improve the interference management. We show by simulation the benefit of combining the three fields: Network Coding, interference consideration and Topology Control. We also deal with delay management for multicast flows and use the Generation-Based Network Coding (GBNC) that combines the packets per blocks. Most of the works on GBNC consider a fixed generation size. Because of the network state variations, the delay of decoding and recovering a block of packets can vary accordingly degrading the QoS. To solve this problem, we propose a network-and content-aware method that adjusts the generation size dynamically to respect a certain decoding delay. We also enhance it to overcome the issue of acknowledgement loss. We then propose to apply our approach in a Home Area Network for Live TV and video streaming. Our solution provides QoS and Quality of Experience for the end user with no additional equipment. Finally, we focus on a more theoretical work in which we present a new Butterfly-based network for multi-source multi-destination flows. We characterize the source node buffer size using the queuing theory and show that it matches the simulation results.
11
Pong, Dennis Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Quality of service support in multi-rate wireless networks". Awarded by:University of New South Wales. School of Electrical Engineering and Telecommunications, 2006. http://handle.unsw.edu.au/1959.4/25153.
Testo completoAbstract (sommario):
Packet switched wireless networks have become increasingly popular due to improvements in transmission speed, ease of deployment and mobility. Wireless technologies such as the IEEE 802.11 Wireless Local Area Networks provide transmission speeds capable of supporting multimedia applications. However, wireless channels suffer from short term effects such as interference and fading, and long term effects such as signal strength changes that are caused by user mobility. In multi-rate networks, stations can adapt to the channel variations by adjusting their physical transmission rates. This introduces resource management problems as resource usage depends on the application's bit rate as well as the physical transmission rate used. Multimedia applications demand consistent Quality of Service (QoS) performance from the network. This does not fit well with the dynamic nature of wireless networks. In this thesis, we propose a link layer resource manager to maintain application QoS requirements in multi-rate wireless networks. It consists of two components - Resource reservation and Medium Access Control (MAC) parameters selection. The resource reservation algorithm determines the current and future amount of channel resources required by a multimedia application and performs the function of admission control. This prevents any new traffic or physical transmission rate changes from degrading the QoS of the admitted traffic. The design of the MAC parameters selection algorithm is based on the IEEE 802.11e Enhanced Distributed Channel Access (EDCA) scheme. The algorithm enables the provision of QoS to individual multimedia applications with the prioritised service of EDCA. Analytical and simulation studies were performed to demonstrate the efficiency and effectiveness of the algorithms. The results highlighted the ability of the algorithms to mitigate the QoS provision problem in multi-rate wireless networks introduced by channel variations.
12
Fung, Ping-yuen, e 馮秉遠. "Online algorithms for the provision of quality of service in networks". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B3158052X.
Testo completo
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Alturki, Raad. "Multimedia ad hoc networks : design, QoS, routing and analysis". Thesis, Swansea University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678520.
Testo completo
14
Ahlin, Karl. "Quality of Service i IP-nätverk". Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1354.
Testo completoAbstract (sommario):
The original promise behind the Internet Protocol was to deliver data from a sender to the receiver using a best-effort approach. This means that the protocol makes no guarantees except that it will try to deliver the data to the destination. If some problem occurs the packet may be discarded by the network without any notice. No guarantees are made regarding the time it takes to deliver the data, the rate at which data will be delivered or if data is delivered in the same order it was sent. The best-effort approach is arguably the reason behind the success of the Internet Protocol and is what makes IP scalable to networks the size of the Internet. However, this approach is also a problem for network operators who want to offer better quality of service to some of their customers. This master thesis will discuss some of the theories behind the implementation of quality of service schemes in an IP network and also provide an example of how to implement it in an existing network.
15
Ghimire, Rajiv, e Mustafa Noor. "Evaluation and Optimization of Quality of Service (QoS) In IP Based Networks". Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3920.
Testo completoAbstract (sommario):
The purpose of this thesis is to evaluate and analyze the performance of RED (Random Early Detection) algorithm and our proposed RED algorithm. As an active queue management RED has been considered an emerging issue in the last few years. Quality of service (QoS) is the latest issue in today’s internet world. The name QoS itself signifies that special treatment is given to the special traffic. With the passage of time the network traffic grew in an exponential way. With this, the end user failed to get the service for what they had paid and expected for. In order to overcome this problem, QoS within packet transmission came into discussion in internet world. RED is the active queue management system which randomly drops the packets whenever congestion occurs. It is one of the active queue management systems designed for achieving QoS. In order to deal with the existing problem or increase the performance of the existing algorithm, we tried to modify RED algorithm. Our purposed solution is able to minimize the problem of packet drop in a particular duration of time achieving the desired QoS. An experimental approach is used for the validation of the research hypothesis. Results show that the probability of packet dropping in our proposed RED algorithm during simulation scenarios significantly minimized by early calculating the probability value and then by calling the pushback mechanism according to that calculated probability value.+46739567385(Rajiv), +46762125426(Mustafa)
16
Heidari, Fariba. "Quality of service routing using decentralized learning". Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115672.
Testo completoAbstract (sommario):
This thesis presents several decentralized, learning-based algorithms for on-line routing of bandwidth guaranteed paths. The presented routing algorithms do not need any a-priori knowledge of traffic demand; they use only their locally observed events and update their routing policy using learning schemes. The employed learning algorithms are either learning automata or the multi-armed bandit algorithms. We investigate the asymptotic behavior of the proposed routing algorithms and prove the convergence of one of them to the user equilibrium. Discrete event simulation results show the merit of these algorithms in terms of improving the resource utilization and increasing the network admissibility compared with shortest path routing.We investigate the performance degradation due to decentralized routing as opposed to centralized optimal routing policies in practical scenarios. The system optimal and the Nash bargaining solutions are two centralized benchmarks used in this study. We provide nonlinear programming formulations of these problems along with a distributed recursive approach to compute the solutions. An on-line partially-decentralized control architecture is also proposed to achieve the system optimal and the Nash bargaining solution performances. Numerical results in some practical scenarios with well engineered networks, where the network resources and traffic demand are well matched, indicate that decentralized learning techniques provide efficient, stable and scalable approaches for routing the bandwidth guaranteed paths.
In the context of on-line learning, we propose a new algorithm to track the best action-selection policy when it abruptly changes over time. The proposed algorithm employs change detection mechanisms to detect the sudden changes and restarts the learning process on the detection of an abrupt change. The performance analysis of this study reveals that when all the changes are detectable by the change detection mechanism, the proposed tracking the best action-selection policy algorithm is rate optimal. On-line routing of bandwidth guaranteed paths with the potential occurrence of network shocks such as significant changes in the traffic demand is one of the applications of the devised algorithm. Simulation results show the merit of the proposed algorithm in tracking the optimal routing policy when it abruptly changes.
17
Lin, Burch. "Neural networks and their application to metrics research". Virtual Press, 1996. http://liblink.bsu.edu/uhtbin/catkey/1014859.
Testo completoAbstract (sommario):
In the development of software, time and resources are limited. As a result, developers collect metrics in order to more effectively allocate resources to meet time constraints. For example, if one could collect metrics to determine, with accuracy, which modules were error-prone and which were error-free, one could allocate personnel to work only on those error-prone modules.There are three items of concern when using metrics. First, with the many different metrics that have been defined, one may not know which metrics to collect. Secondly, the amount of metrics data collected can be staggering. Thirdly, interpretation of multiple metrics may provide a better indication of error-proneness than any single metric.This thesis researched the accuracy of a neural network, an unconventional model, in building a model that can determine whether a module is error-prone from an input of a suite of metrics. The accuracy of the neural network model was compared with the accuracy of a linear regression model, a standard statistical model, that has the same input and output. In other words, we attempted to find whether metrics correlated with error-proneness. The metrics were gathered from three different software projects. The suite of metrics that was used to build the models was a subset of a larger collection of metrics that was reduced using factor analysis.The conclusion of this thesis is that, from the projects analyzed, neither the neural network model nor the logistic regression model provide acceptable accuracies for real use. We cannot conclude whether one model provides better accuracy than the other.Department of Computer Science
18
Phirke, Vishal Vasudeo. "Traffic Sensitive Active Queue Management for Improved Quality of Service". Digital WPI, 2002. https://digitalcommons.wpi.edu/etd-theses/780.
Testo completoAbstract (sommario):
The Internet, traditionally FTP, e-mail and Web traffic, is increasingly supporting emerging applications such as IP telephony, video conferencing and online games. These new genres of applications have different requirements in terms of throughput and delay than traditional applications. For example, interactive multimedia applications, unlike traditional applications, have more stringent delay constraints and less stringent loss constraints. Unfortunately, the current Internet offers a monolithic best-effort service to all applications without considering their specific requirements. Adaptive RED (ARED) is an Active Queue Management (AQM) technique, which optimizes the router for throughput. Throughput optimization provides acceptable QoS for traditional throughput sensitive applications, but is unfair for these new delay sensitive applications. While previous work has used different classes of QoS at the router to accommodate applications with varying requirements, thus far all have provided just 2 or 3 classes of service for applications to choose from. We propose two AQM mechanisms to optimize router for better overall QoS. Our first mechanism, RED-Worcester, is a simple extension to ARED in order to tune ARED for better average QoS support. Our second mechanism, REDBoston, further extends RED-Worcester to improve the QoS for all flows. Unlike earlier approaches, we do not predefine classes of service, but instead provide a continuum from which applications can choose. We evaluate our approach using NS-2 and present results showing the amount of improvement in QoS achieved by our mechanisms over ARED.
19
Zhang, Zhen. "Delivering mobile services to mobile users in open networks: Quality of service, authentication and trust-based access control". Thesis, University of Ottawa (Canada), 2008. http://hdl.handle.net/10393/27745.
Testo completoAbstract (sommario):
This thesis describes scenarios in which a mobile user needs various services, such as Internet telephony, secure printing and online data services in a number of places. From these scenarios we summarize the requirements for quality of service control, service discovery, user authentication and authorization, service access control, and user privacy. In order to implement a prototype to support service discovery, we studied different technologies including Bluetooth, Jini, and Web Services. SDPtool from BlueZ was chosen to limit the search range within the user's local area while using minimal power consumption. Also included in the implementation, the Session Initiation Protocol is used to initiate the session and exchange messages while Java Media Framework is used to capture and deliver multimedia data. In the process of adapting Dupre's authentication protocol for user authentication, we found that it is possible for a third party to intercept the messages exchanged between a user and a Foreign Agent, which may lead to denial of service attack and weakens the strength of the user's password. The protocol is then improved by introducing additional message segments and altering the way to verify the server's response. The thesis also deals with trust relationships, which are needed as a basis for communication between the two parties. Shi's probability distribution model is introduced to integrate recommendations from different domains so that a service provider could make better decisions whether a given user should be assigned certain access rights. In the other hand, a user also depends on a trust relationship to make sure that his or her sensitive data will be handled properly. Finally, based on all of the above, a trust-based access control framework for mobile users and services is proposed and choices of implementation are briefly discussed.
20
Yavari, Najib. "Few-Shot Learning with Deep Neural Networks for Visual Quality Control: Evaluations on a Production Line". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-283119.
Testo completoAbstract (sommario):
Having a well representative and adequate amount of data samples plays an important role in the success of deep learning algorithms used for image recognition. On the other hand, collecting and manually labeling a large-scale dataset requires a great deal of human interaction which in turn is very timeconsuming. In this thesis project, we explore the possibilities of new deeplearning approaches used for image recognition that do not require a big amount of data. Since Few-Shot Learning (FSL) models are known to be the most promising approach to tackle the problem of not having an adequate dataset, a hand full of the state-of-the-art algorithms based on FSL approach such as Model-Agnostic Meta-Learning (MAML), Prototypical Networks (ProtoNet), Relation Networks (RelationNet), Baseline, and Baseline++ are implemented and analyzed. These models are used to classify a series of issues for the automation of the visual quality inspection in a production line. Moreover, the performance of the deeper networks in comparison to the shallower networks is explored. Our experiment results on the available dataset show that the Baseline++ model has the best performance among the other models. Furthermore, Baseline++ with a six-layer convolutional network as a feature backbone is a relatively simple model to train that does not require a high computational power compared to the other models.Inom maskininlärning spelar tillgången till en bra och lämplig mängd data en viktig roll i framgången för djupa inlärningsalgoritmer som används för bildigenkänning. Insamling och manuell märkning av ett storskaligt dataset kräver däremot en hel del mänsklig interaktion som är mycket tidskrävande. I detta examensarbete undersöker vi möjligheterna med nya djupinlärningsmetoder som används för bildigenkänning som inte kräver ett storskaligt dataset. Eftersom Few-Shot Learning (FSL) modeller är kända för att vara den mest lovande metoden för att hantera problemet med att inte ha ett tillräckligt dataset, implementerar och analyserar vi några av de senaste modellerna baserad på FSL, såsom: Model-Agnostic Meta-Learning (MAML), PrototypicalNetworks (ProtoNet), Relation Networks (RelationNet), Baseline, och Baseline++. Dessa modeller används för att klassificera en rad olika defekta produkter för automatisering av den visuella kvalitetskontrollen i en produktionslinje. Vidare undersöks även de djupare nätverkens prestanda i jämförelse med de grundare nätverken. Experimentresultaten på det tillgängliga datasetet visar att Baseline++ modellen har bäst prestanda bland de olika modellerna. Dessutom är Baseline++ med ett sex-lagers faltningsnätverk, en relativt enkel modell att träna som inte kräver en hög beräkningskraft jämfört med de andra modellerna.
21
Kilic, Eda. "Quality Of Service Aware Dynamic Admission Control In Ieee 802.16j Non-transparent Relay Networks". Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611631/index.pdf.
Testo completoAbstract (sommario):
Today, telecommunication is improving rapidly. People are online anywhere anytime. Due to
increasing demand in communication, wireless technologies are progressing quickly trying to
provide more services in a wide range. In order to address mobility and connectivity requirements
of users in wide areas, Worldwide Interoperability for Microwave Access (Wimax) has
been introduced as a forth generation telecommunication technology.
Wimax, which is also called Metropolitan Area Network (MAN), is based on IEEE 802.16
standard where a Base Station (BS) provides last mile broadband wireless access to the end
users known as Mobile Stations (MS). However, in places where high constructions exist,
the signal rate between MS and BS decreases or even the signal can be lost completely due
to shadow fading. As a response to this issue, recently an intermediate node specification,
namely Relay Station, has been defined in IEEE 802.16j standard for relaying, which provides
both throughput enhancement and coverage extension. However, this update has introduced a
new problemcall admission control in non-transparent relay networks that support coverage extension. In this thesis, a Quality of Service (QoS) aware dynamic admission control algorithm for IEEE 802.16j non-transparent relay networks is introduced. Our objectives are admitting more service flows, utilizing the bandwidth, giving individual control to each relay station (RS) on call acceptance and rejection, and finally not affecting ongoing service flow quality in an RS due to the dense population of service flows in other RSs. The simulation results show that the proposed algorithm outperforms the other existing call admission control algorithms. Moreover, this algorithm can be interpreted as pioneer call admission control algorithm in IEEE 802.16j non-transparent networks.
22
Fornaro, Antony. "Testbed evaluation of integrating ethernet switches in the differentiated services architecture using virtual LANs". Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/15684.
Testo completo
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Stucki, Eric Thomas. "Medium Access Control and Networking Protocols for the Intra-Body Network". Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1182.pdf.
Testo completo
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Xiao, Chunpeng. "Advanced link and transport control protocols for broadband optical access networks". Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-11082006-183908/.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007.Chang, Gee-Kung, Committee Chair ; Zhou, G.Tong, Committee Member ; Copeland, John, Committee Member ; Riley, George, Committee Member ; Ingram, Mary Ann, Committee Member ; Ammar, Mostafa, Committee Member.
25
Chin, Bruce Lorenz. "An investigation in using artificial neural networks for quality control in the poultry industry". Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/17989.
Testo completo
26
Kuri, Joy. "Optimal Control Problems In Communication Networks With Information Delays And Quality Of Service Constraints". Thesis, Indian Institute of Science, 1995. http://hdl.handle.net/2005/162.
Testo completoAbstract (sommario):
In this thesis, we consider optimal control problems arising in high-speed integrated communication networks with Quality of Service (QOS) constraints. Integrated networks are expected to carry a large variety of traffic sources with widely varying traffic characteristics and performance requirements. Broadly, the traffic sources fall into two categories: (a) real-time sources with specified performance criteria, like small end to end delay and loss probability (sources of this type are referred to as Type 1 sources below), and (b) sources that do not have stringent performance criteria and do not demand performance guarantees from the network - the so-called Best Effort Type sources (these are referred to as Type 2 sources below). From the network's point of view, Type 2 sources are much more "controllable" than Type 1 sources, in the sense that the Type 2 sources can be dynamically slowed down, stopped or speeded up depending on traffic congestion in the network, while for Type 1 sources, the only control action available in case of congestion is packet dropping. Carrying sources of both types in the same network concurrently while meeting the performance objectives of Type 1 sources is a challenge and raises the question of equitable sharing of resources. The objective is to carry as much Type 2 traffic as possible without sacrificing the performance requirements of Type 1 traffic.
We consider simple models that capture this situation. Consider a network node through which two connections pass, one each of Types 1 and 2. One would like to maximize the throughput of the Type 2 connection while ensuring that the Type 1 connection's performance objectives are met. This can be set up as a constrained optimization problem that, however, is very hard to solve. We introduce a parameter b that represents the "cost" of buffer occupancy by Type 2 traffic. Since buffer space is limited and shared, a queued Type 2 packet means that a buffer position is not available for storing a Type 1 packet; to discourage the Type 2 connection from hogging the buffer, the cost parameter b is introduced, while a reward for each Type 2 packet coming into the buffer encourages the Type 2 connection to transmit at a high rate.
Using standard on-off models for the Type 1 sources, we show how values can be assigned to the parameter b; the value depends on the characteristics of the Type 1 connection passing through the node, i.e., whether it is a Variable Bit Rate (VBR) video connection or a Continuous Bit Rate (CBR) connection etc. Our approach gives concrete networking significance to the parameter b, which has long been considered as an abstract parameter in reward-penalty formulations of flow control problems (for example, [Stidham '85]).
Having seen how to assign values to b, we focus on the Type 2 connection next. Since Type 2 connections do not have strict performance requirements, it is possible to defer transmitting a Type 2 packet, if the conditions downstream so warrant. This leads to the question: what is the "best" transmission policy for Type 2 packets? Decisions to transmit or not must be based on congestion conditions downstream; however, the network state that is available at any instant gives information that is old, since feedback latency is an inherent feature of high speed networks. Thus the problem is to identify the best transmission policy under delayed feedback information.
We study this problem in the framework of Markov Decision Theory. With appropriate assumptions on the arrivals, service times and scheduling discipline at a network node, we formulate our problem as a Partially Observable Controlled Markov Chain (PO-CMC). We then give an equivalent formulation of the problem in terms of a Completely Observable Controlled Markov Chain (CO-CMC) that is easier to deal with., Using Dynamic Programming and Value Iteration, we identify structural properties of an optimal transmission policy when the delay in obtaining feedback information is one time slot. For both discounted and average cost criteria, we show that the optimal policy has a two-threshold structure, with the threshold on the observed queue length depending, on whether a Type 2 packet was transmitted in the last slot or not.
For an observation delay k > 2, the Value Iteration technique does not yield results. We use the structure of the problem to provide computable upper and lower bounds to the optimal value function. A study of these bounds yields information about the structure of the optimal policy for this problem. We show that for appropriate values of the parameters of the problem, depending on the number of transmissions in the last k steps, there is an "upper cut off" number which is a value such that if the observed queue length is greater than or equal to this number, the optimal action is to not transmit. Since the number of transmissions in the last k steps is between 0 and A: both inclusive, we have a stack of (k+1) upper cut off values. We conjecture that these (k + l) values axe thresholds and the optimal policy for this problem has a (k + l)-threshold structure.
So far it has been assumed that the parameters of the problem are known at the transmission control point. In reality, this is usually not known and changes over time. Thus, one needs an adaptive transmission policy that keeps track of and adjusts to changing network conditions. We show that the information structure in our problem admits a simple adaptive policy that performs reasonably well in a quasi-static traffic environment.
Up to this point, the models we have studied correspond to a single hop in a virtual connection. We consider the multiple hop problem next. A basic matter of interest here is whether one should have end to end or hop by hop controls. We develop a sample path approach to answer this question. It turns out that depending on the relative values of the b parameter in the transmitting node and its downstream neighbour, sometimes end to end controls are preferable while at other times hop by hop controls are preferable.
Finally, we consider a routing problem in a high speed network where feedback information is delayed, as usual. As before, we formulate the problem in the framework of Markov Decision Theory and apply Value Iteration to deduce structural properties of an optimal control policy. We show that for both discounted and average cost criteria, the optimal policy for an observation delay of one slot is Join the Shortest Expected Queue (JSEQ) - a natural and intuitively satisfactory extension of the well-known Join the Shortest Queue (JSQ) policy that is optimal when there is no feedback delay (see, for example, [Weber 78]). However, for an observation delay of more than one slot, we show that the JSEQ policy is not optimal. Determining the structure of the optimal policy for a delay k>2 appears to be very difficult using the Value Iteration approach; we explore some likely policies by simulation.
27
Beyah, Raheem A. "A deployable framework for providing better than best-effort quality of service for traffic flows". Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/15393.
Testo completo
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Reddy, Pavan K. "Implementation of an available bit rate service for satellite IP networks using a performance enhancing proxy". Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-0429104-100149/.
Testo completo
29
Nam, Kyungdoo T. "A Heuristic Procedure for Specifying Parameters in Neural Network Models for Shewhart X-bar Control Chart Applications". Thesis, University of North Texas, 1993. https://digital.library.unt.edu/ark:/67531/metadc278815/.
Testo completoAbstract (sommario):
This study develops a heuristic procedure for specifying parameters for a neural network configuration (learning rate, momentum, and the number of neurons in a single hidden layer) in Shewhart X-bar control chart applications. Also, this study examines the replicability of the neural network solution when the neural network is retrained several times with different initial weights.
30
Zhang, Jinfang. "Soft Handoff in MC-CDMA Cellular Networks Supporting Multimedia Services". Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/842.
Testo completoAbstract (sommario):
An adaptive resource reservation and handoff priority scheme, which jointly considers the characteristics from the physical, link and network layers, is proposed for a packet switching Multicode (MC)-CDMA cellular network supporting multimedia applications. A call admission region is derived for call admission control (CAC) and handoff management with the satisfaction of quality of service (QoS) requirements for all kinds of multimedia traffic, where the QoS parameters include the wireless transmission bit error rate (BER), the packet loss rate (PLR) and delay requirement. The BER requirement is guaranteed by properly arranging simultaneous packet transmissions, whereas the PLR and delay requirements are guaranteed by the proposed packet scheduling and partial packet integration scheme. To give service priority to handoff calls, a threshold-based adaptive resource reservation scheme is proposed on the basis of a practical user mobility model and a proper handoff request prediction scheme. The resource reservation scheme gives handoff calls a higher admission priority over new calls, and is designed to adjust the reservation-request time threshold adaptively according to the varying traffic load. The individual reservation requests form a common reservation pool, and handoff calls are served on a first-come-first-serve basis. By exploiting the transmission rate adaptability of video calls to the available radio resources, the resources freed from rate-adaptive high-quality video calls by service degradation can be further used to prioritize handoff calls. With the proposed resource reservation and handoff priority scheme, the dynamic properties of the system can be closely captured and a better grade of service (GoS) in terms of new call blocking and handoff call dropping probabilities(rates) can be achieved compared to other schemes in literature. Numerical results are presented to show the improvement of the GoS performance and the efficient utilization of the radio resources.
31
Chen, Xi. "Dynamic resource allocation scheme design for quality of service control in networked real-time systems". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114473.
Testo completoAbstract (sommario):
Networked real-time systems (NRSs) are pervasive in the real world, and many of them work in an open environment with varying workload. Quality of service (QoS) of NRSs is closely related to the provision of the system resources for servingthe real-time tasks. To provide guarantees of QoS in NRSs, the system resources should be allocated to the real-time tasks in adaptation to the workload variations so that the desired system performance is obtained, referred to as QoS control.This thesis is concerned with the design of dynamic resource allocation schemes for QoS control in three typical NRSs. In the first part, we propose dynamic computing capacity planning schemes for processor utilization control in the distributed real-time systems, and for energy minimization with request response time guarantees in the server clusters. To handle the workload variations, we model the workload uncertainties as the parameters in the system models and use the system performance as online feedback to predict these parameters as precise as possible. Then the optimal computing capacities are provided to serve the real-time tasks in these systems online. Experimental/simulation results demonstrate effectiveness of the proposed schemes for QoS control in comparisons with the existing approaches. In the second part, we propose a dynamic network scheduling scheme for networked control systems (NCSs), typical NRSs with network bandwidth as a critical system resource. The proposed scheduling scheme can properly allocate the network bandwidth to the applications in NCSs so that the good real-time performance can be achieved.Les systèmes temps-réel en réseau (NRSs) sont de plus en plus utilisés, et beaucoup d'entre eux fonctionnent dans un environnement ouvert aux charges variables. La Qualité de Service (QoS) des NRSs dépend des ressources systèmes pour répondre aux taches en temps-réel. Pour garantir la QoS, les ressources système doivent être allouées dynamiquement, en s'adaptant aux variations de charge, ceci dans le but d'atteindre les performances désirées.Cette thèse traite de la conceptions de méthodes d'allocation dynamique des ressources dans le but d'assurer la QoS dans le cas de 3 NRSs représentatifs. Nous commencerons pas proposer des méthodes de plannification de capacités pour le contrôle de l'utilisation du processeur dans les systèmes distribués, à coup énergétique minimal, avec temps de réponse garanti. Pour supporter les variations de charge, nous utilisons les performances du système pour prédire l'évolution de la charge à venir aussi précisement que possible. Ensuite, les ressources optimales sont libéréespour répondre aux besoins en temp-réel. Les resultats des expérimentations / simulations démontrent l'efficacité de ces méthodes sur le contrôle de la QoS, en comparaison à d'autres approches existantes. Dans un second temps, nous proposerons une méthodologie de séquençage réseau dynamique pour les systèmes controlés en réseau (NCSs), un NRS commun dépendant fortement de la bande passante du réseau. La méthodologie proposée peut correctement allouer la bande passante aux applications du NCS de sorte que de bonnesperformances soient atteintes.
32
Nguyen, Tuan Dung. "Performance evaluation of optical packet switching technology : access control, resource allocation and QoS management for metropolitan and access networks". Phd thesis, Institut National des Télécommunications, 2010. http://tel.archives-ouvertes.fr/tel-00688808.
Testo completoAbstract (sommario):
The rapid growth in client application demands, in terms of bandwidth and (QoS), has motivated the deployment of the optical technology at Metro Access and Metro Core Networks. More diverse and more intelligent optic devices are required for efficiently management of huge capacity in the network. The explosion in demand for network bandwidth is mainly due to the growth in data traffic whose nature is also becoming more and more complex. In general, most of service-based traffics are transported in networks which are now being dominated by the optical switching technology. Nevertheless, such technology has some drawbacks such as inflexible and non-scalable properties. (OPS), which offers significant benefits in terms of both network efficiency and control scalability, may overcome these limitations. This has motivated the orientation from optical circuit switching to optical packet switching in the future network infrastructure. In reality, optical packet switching ring (OPSR) networks, which combine the packet switching technology with the well-known advantages of ring topology such as fast service restoration in cases of failure and high gain of statistical traffic multiplexing over the ring, appear to be the technology of choice for the next generation of Metro Area Networks. A new OPSR architecture which is based on the all-optical infrastructure that offers intelligent features with lower cost while maximizing processing time and is now considering being replaced existing opto-electronic architectures such as Resilient Packet Ring, have been presented in the scope of the dissertation. The key element of such network is Packet Optical Add/Drop Multiplexer (POADM) which is implemented inside a ring node, allowing the node to exploit the optical transparency. This dissertation hence focuses on the performance evaluation of the new generation of OPSR network. In this dissertation, we have investigated the performance analysis (in terms of packet delay and queue-length distribution of access nodes) of an optical synchronous bus-based metropolitan network supporting fixed-size packets. We have modeled each access node by an embedded discrete time Markov chain (EDTMC). The solution of the EDTMC allows us to compute the approximate probability that access nodes on the bus "see" free slots in the transit line. Using a recursive analysis technique, we approximately outline the mean waiting time of client packets coming from the upper layer as well as an approximate queue-length distribution of local buffers at access nodes in two cases: with and without QoS guarantees. To characterize the performance of an asynchronous OPSR network, we have evaluated the impact of Optical fixed-Size Packet Creation on the network performance without and with different quality of services (QoS) requirements. Performance analysis of such systems has allowed us to identify a reasonable combination of some parameters (timeslot duration, timer expiration values, profile of client traffic and network load) which may be able to improve the bandwidth utilization of the network for a given traffic matrix. The most important point that we have mentioned in the dissertation is the comparison of two architectural approaches: Variable Length - Optical Packet Format (VL-OPF) model supporting empty packets versus Fixed Length - Optical Packet Format (FL-OPF) model. In addition to CoS-Upgrade Mechanism (CUM) which is proposed to improve the filling ratio of the optical container, we have proposed a novel mechanism named Dynamic CoS-Upgrade Mechanism (DCUM) where timers are dynamically changed according to the state of the local buffer of network nodes and the traffic circulating in the network, in order to create containers with a high filling ratio while limiting the time needed for their creation.
33
Hui, Kin Cheung. "The design and implementation of a MPEG video system with transmission control and QoS support". HKBU Institutional Repository, 2002. http://repository.hkbu.edu.hk/etd_ra/446.
Testo completo
34
Banús, Paradell Núria. "New solutions to control robotic environments: quality control in food packaging". Doctoral thesis, Universitat de Girona, 2021. http://hdl.handle.net/10803/673469.
Testo completoAbstract (sommario):
Machine vision systems and artificial intelligence techniques are two active research areas
in the context of Industry 4.0. Their combination allows the reproduction of human
procedures while improving the performance of the processes. However, to achieve the
desired full automation, there is a need for new applications able to cover as many
industrial scenarios and processes as possible. One of the areas that needs further research
and development is the quality control of food packaging, and more specifically
in the closure and sealing control of thermoforming packages. The shortcomings in this
area were detected by TAVIL who, in collaboration with GILAB, proposed an Industrial
Doctorate to investigate, develop and integrate in real scenarios new methods to
improve the packaging stage of the food industry by using machine vision systems and
artificial intelligence techniques. In the context of this Industrial Doctorate, two focuses
of research were defined that differ at the level at which the problem is studied. The
first focused on the quality control of food packages, and the second on the efficient
management of machine vision systems in industrial scenariosEls sistemes de visió per computador i les tècniques d’intel·ligència artificial són dues àrees de recerca actives en el context de la Indústria 4.0. La seva combinació permet la reproducció de procediments humans millorant al mateix temps el rendiment dels processos. Malgrat això, per aconseguir l’automatització completa desitjada, hi ha la necessitat de noves aplicacions capaces de cobrir el màxim d’escenaris i processos industrials possibles. Una de les àrees que necessita més investigació i desenvolupament és el control de qualitat dels envasos d’aliments, i més concretament, el control del tancament i del segellat d’envasos termoformats. Les necessitats en aquesta àrea van ser identificades per TAVIL que, amb col·laboració amb GILAB, van proposar un Doctorat Industrial per investigar, desenvolupar i integrar en escenaris reals nous mètodes per millorar l’etapa d’envasat de la indústria alimentària mitjançant sistemes de visió per computador i tècniques d’intel·ligència artificial. En el context d’aquest Doctorat Industrial, s’han seguit dues línies d’investigació que es diferencien en el nivell en el qual estudien el problema. La primera línia es basa en el control de qualitat d’envasos d’aliments, mentre que la segona es basa en el control eficient de sistemes de visió per computador en escenaris industrials
Programa de Doctorat en Tecnologia
35
Brosnan, Timothy Myers. "Neural network and vector quantization classifiers for recognition and inspection applications". Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/15378.
Testo completo
36
Guan, Lin. "Discrete-time stochastic modelling of congestion control mechanisms with quality of service constraints : an investigation of the use of queue thresholds in controlling congestion and maintaining quality of service constraints in computer networks". Thesis, University of Bradford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.560538.
Testo completo
37
Ruxwana, Nkqubela. "The adoption of quality assurance in e-Health acquisition for rural hospitals in the Eastern Cape Province". Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1514.
Testo completoAbstract (sommario):
The evolution of e-health has the potential to assist in the management of scarce resources and the shortage of skills, enhance efficiencies, improve quality and increase work productivity within the healthcare sector. As a result, an increase is seen in e-health solutions developments with the aim to improve healthcare services, hospital information systems, health decision support, telemedicine and other technical systems that have the potential to reduce cost, improve quality, and enhance the accessibility and delivery of healthcare. However, unfortunately their implementation contiues to fail. Although there are several reasons for this, in this study a lack of project quality management is viewed as a key contributor to the failure of e-health solutions implementation projects in rural hospitals. This results in neglected aspects of quality assurance (QA), which forms an integral part of project quality management. The purpose of this study is to develop a Genertic Quality Assurance Model (GQAM) for the successful acquisition (i.e. development and implementation) of e-health solutions in rural hospitals in the Eastern Cape Province to enable improved quality of care and service delivery. In order to develop and test this model it was necessary to identify the QA methodologies that are currently used in rural hospitals and to evaluate their strengths and weaknesses, as well as their impact on project success. The study is divided into four phases; in each phase different study designs were followed. The study used triangulation of qualitative and some elements of quantitative research approaches, in terms of which a case study approach was adpoted to answer the research questions. This study did indeed develop a GQAM that can be used to ensure e-health solution success in rural hospitals. Furthermore, to aid in the implementation of this model, a set of QA value chain implementation guidelines were developed, as a framework, to inject the nodel into typical (SDLC) phases.
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Silva, Wyllian Bezerra da. "Métodos sem referência baseados em características espaço-temporais para avaliação objetiva de qualidade de vídeo digital". Universidade Tecnológica Federal do Paraná, 2013. http://repositorio.utfpr.edu.br/jspui/handle/1/525.
Testo completoAbstract (sommario):
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)O desenvolvimento de métodos sem referência para avaliação de qualidade de vídeo é um assunto incipiente na literatura e desafiador, no sentido de que os resultados obtidos pelo método proposto devem apresentar a melhor correlação possível com a percepção do Sistema Visual Humano. Esta tese apresenta três propostas para avaliação objetiva de qualidade de vídeo sem referência baseadas em características espaço-temporais. A primeira abordagem segue um modelo analítico sigmoidal com solução de mínimos quadrados que usa o método Levenberg-Marquardt e a segunda e terceira abordagens utilizam uma rede neural artificial Single-Hidden Layer Feedforward Neural Network com aprendizado baseado no algoritmo Extreme Learning Machine. Além disso, foi desenvolvida uma versão estendida desse algoritmo que busca os melhores parâmetros da rede neural artificial de forma iterativa, segundo um simples critério de parada, cujo objetivo é aumentar a correlação entre os escores objetivos e subjetivos. Os resultados experimentais, que usam técnicas de validação cruzada, indicam que os escores dos métodos propostos apresentam alta correlação com as escores do Sistema Visual Humano. Logo, eles são adequados para o monitoramento de qualidade de vídeo em sistemas de radiodifusão e em redes IP, bem como podem ser implementados em dispositivos como decodificadores, ultrabooks, tablets, smartphones e em equipamentos Wireless Display (WiDi).
The development of no-reference video quality assessment methods is an incipient topic in the literature and it is challenging in the sense that the results obtained by the proposed method should provide the best possible correlation with the evaluations of the Human Visual System. This thesis presents three proposals for objective no-reference video quality evaluation based on spatio-temporal features. The first approach uses a sigmoidal analytical model with leastsquares solution using the Levenberg-Marquardt method. The second and third approaches use a Single-Hidden Layer Feedforward Neural Network with learning based on the Extreme Learning Machine algorithm. Furthermore, an extended version of Extreme Learning Machine algorithm was developed which looks for the best parameters of the artificial neural network iteratively, according to a simple termination criteria, whose goal is to increase the correlation between the objective and subjective scores. The experimental results using cross-validation techniques indicate that the proposed methods are correlated to the Human Visual System scores. Therefore, they are suitable for the monitoring of video quality in broadcasting systems and over IP networks, and can be implemented in devices such as set-top boxes, ultrabooks, tablets, smartphones and Wireless Display (WiDi) devices.
39
Kangude, Shantanu. "CSMA with Implicit Scheduling through State-keeping: A Distributed MAC Framework for QoS in Broadcast LANs". Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-05132004-132109/unrestricted/kangude%5Fshantanu%5F200407%5Fphd.pdf.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2005. Directed by John Copeland.Copeland, John, Committee Chair ; Owen, Henry, Committee Member ; Sivakumar, Raghupathy, Committee Member ; Lanterman, Aaron, Committee Member ; Dos Santos, Andre, Committee Member. Includes bibliographical references.
40
Ouyang, Wenbin. "On-Loom Fabric Defect Inspection Using Contact Image Sensors and Activation Layer Embedded Convolutional Neural Network". Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1404537/.
Testo completoAbstract (sommario):
Malfunctions on loom machines are the main causes of faulty fabric production. An on-loom fabric inspection system is a real-time monitoring device that enables immediate defect detection for human intervention. This dissertation presented a solution for the on-loom fabric defect inspection, including the new hardware design—the configurable contact image sensor (CIS) module—for on-loom fabric scanning and the defect detection algorithms. The main contributions of this work include (1) creating a configurable CIS module adaptable to a loom width, which brings CIS unique features, such as sub-millimeter resolution, compact size, short working distance and low cost, to the fabric defect inspection system, (2) designing a two-level hardware architecture that can be efficiently deployed in a weaving factory with hundreds of looms, (3) developing a two-level inspecting scheme, with which the initial defect screening is performed on the Raspberry Pi and the intensive defect verification is processed on the cloud server, (4) introducing the novel pairwise-potential activation layer to a convolutional neural network that leads to high accuracies of defect segmentation on fabrics with fine and imbalanced structures, (5) achieving a real-time defect detection that allows a possible defect to be examined multiple times, and (6) implementing a new color segmentation technique suitable for processing multi-color fabric defects.
The novel CIS-based on-loom scanning system offered real-time and high-resolution fabric images, which was able to deliver the information of single thread on a fabric. The algorithm evaluation on the fabric defect datasets showed a non-miss-detection rate on defect-free fabrics. The average precision of defect existed images reached above 90% at the pixel level. The detected defect pixels' integrity—the recall scored around 70%. Possible defect regions overestimated on ground truth images and the morphologies of fine defects similar to regular fabric pattern were the two major reasons that caused the imperfection in defect pixel locating. The experiments showed the defect areas on multi-color fabrics could be precisely located under the proposed color segmentation algorithm.
41
Jourjon, Guillaume Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Towards a versatile transport protocol". Awarded by:University of New South Wales. Electrical Engineering & Telecommunications, 2008. http://handle.unsw.edu.au/1959.4/41480.
Testo completoAbstract (sommario):
This thesis presents three main contributions that aim to improve the transport layer of the current networking architecture. The transport layer is nowadays dominated by the use of TCP and its congestion control. Recently new congestion control mechanisms have been proposed. Among them, TCP Friendly Hate Control (TFRC) appears to be one of the most complete. Nevertheless this congestion control mechanism, as with TCP, does not take into account either the evolution of the network in terms of Quality of Service and mobility or the evolution of the applications. The first contribution of this thesis is a specialisation of TFRC congestion control to provide a QoS-aware Transport Protocol specifically designed to operate over QoS-enabled networks with bandwidth guarantee mechanisms. This protocol combines a QoS-aware congestion control, which takes into account network-level bandwidth reservations, with full ordered reliability mechanism to provide a transport service similar to TCP. As a result, we obtain the guaranteed throughput at the application level where TCP fails. This protocol is t he first transport protocol compliant with bandwidth guaranteed networks. At the same time the set of network services expands, new technologies have been proposed and deployed at the physical layer. These new technologies are mainly characterised by communications done without wire constraint and the mobility of the end-systems. Furthermore, these technologies are usually deployed on entities where the CPU power and memory storage are limited. The second contribution of this thesis is therefore to propose an adaptation of TFHC to these entities. This is accomplished with the proposition of a new sender-based version of TFHC. This version has been implemented, evaluated and its numerous contributions and advantages compare to usual TFHC version have been demonstrated. Finally, we proposed an optimisation of actual implementations of TFHC. This optimisation first consists in the proposition of an algorithm based on a numerical analysis of the equation used in TFHC and the use of the Newton's algorithm. We furthermore give a first step, with the introduction of a new framework for TFRC, in order to better understand TFHC behaviour and to optimise the computation of the packet loss rate according to loss probability distributions.
42
Iyengar, Navneet. "Providing QoS in Autonomous and Neighbor-aware multi-hop Wireless Body Area Networks". University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439306913.
Testo completo
43
Boubrima, Ahmed. "Deployment and scheduling of wireless sensor networks for air pollution monitoring". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI018.
Testo completoAbstract (sommario):
Les réseaux de capteurs sans fil (RCSF) sont largement utilisés dans les applications environnementales où l’objectif est de détecter un phénomène physique tel que la température, l’humidité, la pollution de l’air, etc. Dans ce contexte d’application, l’utilisation de RCSF permet de comprendre les variations du phénomène et donc être en mesure de prendre des décisions appropriées concernant son impact. En raison des limitations de ses méthodes de suivi traditionnelles et de sa grande variabilité spatiale et temporelle, la pollution de l'air est considérée comme l'un des principaux phénomènes physiques qui restent à étudier et à caractériser. Dans cette thèse, nous considérons trois applications concernant l’utilisation de RCSF pour le suivi de la pollution de l’air : la cartographie en temps réel de la qualité de l’air, la détection de dépassements de seuils des polluants et la correction de modèles physiques qui simulent le phénomène de dispersion de la pollution. Toutes ces applications nécessitent de déployer et d’ordonnancer minutieusement les capteurs afin de mieux comprendre la pollution atmosphérique tout en garantissant un coût de déploiement minimal et en maximisant la durée de vie du réseau. Notre objectif est de résoudre les problèmes de déploiement et d'ordonnancement tout en tenant compte des caractéristiques spécifiques du phénomène de la pollution de l’air. Nous proposons pour chaque cas d'application une approche efficace pour le déploiement de noeuds capteurs et puits. Nous proposons également une approche d’ordonnancement adaptée au cas de la correction de modèles physiques. Nos approches d'optimisation prennent en compte la nature physique de la pollution atmosphérique et intègrent les données réelles fournies par les plateformes existantes de suivi de la qualité de l’air. Dans chacune de nos approches d’optimisation, nous utilisons la programmation linéaire en nombres entiers pour concevoir des modèles d’optimisation adaptés à la résolution de petites et moyennes instances. Pour traiter les grandes instances, nous proposons des heuristiques en utilisant des techniques de relaxation linéaire. Outre nos travaux théoriques sur le suivi de la pollution atmosphérique, nous avons conçu et déployé dans la ville de Lyon un réseau de capteurs de pollution économe en énergie. Sur la base des caractéristiques de notre système et des jeux de données de la pollution atmosphérique, nous avons évalué l’efficacité de nos approches de déploiement et d’ordonnancement. Nous présentons et discutons dans cette thèse les résultats d'évaluation de performances ainsi que des lignes directrices pour la conception de systèmes de suivi de la pollution de l’air. Parmi nos principales conclusions, nous soulignons le fait que la taille optimale du réseau de capteurs dépend du degré de variation des concentrations de pollution dans la région de déploiementWireless sensor networks (WSN) are widely used in environmental applications where the aim is to sense a physical phenomenon such as temperature, humidity, air pollution, etc. In this context of application, the use of WSN allows to understand the variations of the phenomenon over the monitoring region and therefore be able to take adequate decisions regarding the impact of the phenomenon. Due to the limitations of its traditional costly monitoring methods in addition to its high spatial and temporal variability, air pollution is considered as one of the main physical phenomena that still need to be studied and characterized. In this thesis, we consider three main applications regarding the use of WSN for air pollution monitoring: 1) the construction of real time air quality maps using sensor measurements; 2) the detection of pollution threshold crossings; and 3) the correction of physical models that simulate the pollution dispersion phenomenon. All these applications need careful deployment and scheduling of sensors in order to get a better knowledge of air pollution while ensuring a minimal deployment cost and a maximal lifetime of the deployed sensor network. Our aim is to tackle the problems of WSN deployment and scheduling while considering the specific characteristics of the air pollution phenomenon. We propose for each application case a new efficient approach for the deployment of sensor and sink nodes. We also propose a WSN scheduling approach that is adapted to the case of physical models’ correction. Our optimization approaches take into account the physical nature of air pollution dispersion and incorporate real data provided by the existing pollution sensing platforms. As part of each approach, we use integer linear programming to derive optimization models that are well adapted to solving small and medium instances. To deal with large instances, we propose heuristic algorithms while using linear relaxation techniques. Besides our theoretical works on air pollution monitoring, we design from scratch and deploy in the Lyon city a cost-effective energy-efficient air pollution sensor network. Based on the characteristics of our monitoring system in addition to real world air pollution datasets, we evaluate the effectiveness of our deployment and scheduling approaches and provide engineering insights for the design of WSN-based air pollution monitoring systems. Among our conclusions, we highlight the fact that the size of the optimal sensor network depends on the degree of the variations of pollution concentrations within the monitoring region
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Van, der Linde P. L. "A comparative study of three ICT network programs using usability testing". Thesis, [Bloemfontein?] : Central University of Technology, Free State, 2013. http://hdl.handle.net/11462/186.
Testo completoAbstract (sommario):
Thesis (M. Tech. (Information Technology)) -- Central University of technology, Free State, 2013This study compared the usability of three Information and Communication Technology (ICT) network programs in a learning environment. The researcher wanted to establish which program was most adequate from a usability perspective among second-year Information Technology (IT) students at the Central University of Technology (CUT), Free State. The Software Usability Measurement Inventory (SUMI) testing technique can measure software quality from a user perspective. The technique is supported by an extensive reference database to measure a software product’s quality in use and is embedded in an effective analysis and reporting tool called SUMI scorer (SUMISCO). SUMI was applied in a controlled laboratory environment where second-year IT students of the CUT, utilized SUMI as part of their networking subject, System Software 1 (SPG1), to evaluate each of the three ICT network programs. The results, strengths and weaknesses, as well as usability improvements, as identified by SUMISCO, are discussed to determine the best ICT network program from a usability perspective according to SPG1 students.
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Schneider, C. "Using unsupervised machine learning for fault identification in virtual machines". Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7327.
Testo completoAbstract (sommario):
Self-healing systems promise operating cost reductions in large-scale computing environments through the automated detection of, and recovery from, faults. However, at present there appears to be little known empirical evidence comparing the different approaches, or demonstrations that such implementations reduce costs. This thesis compares previous and current self-healing approaches before demonstrating a new, unsupervised approach that combines artificial neural networks with performance tests to perform fault identification in an automated fashion, i.e. the correct and accurate determination of which computer features are associated with a given performance test failure. Several key contributions are made in the course of this research including an analysis of the different types of self-healing approaches based on their contextual use, a baseline for future comparisons between self-healing frameworks that use artificial neural networks, and a successful, automated fault identification in cloud infrastructure, and more specifically virtual machines. This approach uses three established machine learning techniques: Naïve Bayes, Baum-Welch, and Contrastive Divergence Learning. The latter demonstrates minimisation of human-interaction beyond previous implementations by producing a list in decreasing order of likelihood of potential root causes (i.e. fault hypotheses) which brings the state of the art one step closer toward fully self-healing systems. This thesis also examines the impact of that different types of faults have on their respective identification. This helps to understand the validity of the data being presented, and how the field is progressing, whilst examining the differences in impact to identification between emulated thread crashes and errant user changes – a contribution believed to be unique to this research. Lastly, future research avenues and conclusions in automated fault identification are described along with lessons learned throughout this endeavor. This includes the progression of artificial neural networks, how learning algorithms are being developed and understood, and possibilities for automatically generating feature locality data.
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Sousa, Ligia Maria Carvalho. "Esquema de controle adaptativo de fluxos de trafego baseado em modelagem fuzzy preditiva". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259424.
Testo completoAbstract (sommario):
Orientadores: Lee Luan Ling, Flavio Henrique Teles VieiraDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-09T03:15:16Z (GMT). No. of bitstreams: 1 Sousa_LigiaMariaCarvalho_M.pdf: 2110733 bytes, checksum: 2417de66d2ca06dcb86fbce5e919906e (MD5) Previous issue date: 2007
Resumo: O presente trabalho propõe um esquema de controle adaptativo de ?uxos baseado no modelo fuzzy TSK. Neste esquema de controle, o modelo fuzzy TSK é utilizado para prever adaptativamente o tamanho da ?la no buffer em um enlace. Com o objetivo de ajustar dinamicamente os parâmetros do modelo fuzzy TSK, propomos um algoritmo de treinamento adaptativo. Na primeira etapa do algoritmo de treinamento proposto, os parâmetros das partes premissas e das partes conseqüentes do modelo são obtidos. A segunda etapa consiste de um algoritmo de re?namento dos parâmetros do modelo baseado em gradiente descendente. A e?ciência do preditor proposto é avaliada através da comparação com outros preditores adaptativos fazendo uso de traços de tráfego reais. A partir dos parâmetros do modelo fuzzy TSK, derivamos uma expressão para a taxa da fonte controlável a qual minimiza a variância do tamanho de ?la no buffer. O controle de congestionamento proposto é então aplicado em diferentes cenários de rede com vários nós. Comparações realizadas com outros métodos de controle de congestionamento demonstram que o controle de congestionamento proposto obtém menores taxas de perdas e consegue de fato manter o tamanho da ?la no buffer abaixo do valor desejado
Abstract: The present work proposes a adaptive control of traf?c ?ows based in the TSK fuzzy model. In this control, the TSK fuzzy model is used to predict in a manner adaptive the buffer length in one output link. With the objective of dynamically adjust the parameters of the TSK fuzzy model, we proposed a adaptive training algorithm. In the ?rst stage of the proposed training algorithm, the parameters of the premise and consequent parts of the model are obtained. The second stage consists of a re?ning algorithm of the parameters based in descent gradient. The effectiveness of the proposed predictor is evaluated through comparison with other adaptive predictors by using real network traf?c traces. With the parameters of the TSK model, we derive an expression for the controllable source rate which minimizes the variance of the buffer length. The proposed congestion control is applied in different network sceneries with several nodes. Comparison made with others congestion control methods demonstrates that the proposed congestion control obtain lesser loss rate and gets in fact to keep the buffer length below of the reference level
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
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Garcia, Sotelo Gerardo Javier. "Get the right price every day". CSUSB ScholarWorks, 2005. https://scholarworks.lib.csusb.edu/etd-project/2729.
Testo completoAbstract (sommario):
The purpose of this project is to manage restaurants using a software system called GRIPED (Get the Right Price Every day). The system is designed to cover quality control, food cost control and portion control for better management of a restaurant.
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Wikstrand, Greger. "Human factors and wireless network applications : more bits and better bits". Doctoral thesis, Umeå : Department of Computing Science, Umeå Univ, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-910.
Testo completo
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Kunert, Kristina. "Architectures and Protocols for Performance Improvements of Real-Time Networks". Doctoral thesis, Högskolan i Halmstad, Inbyggda system (CERES), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-14082.
Testo completoAbstract (sommario):
When designing architectures and protocols for data traffic requiring real-time services, one of the major design goals is to guarantee that traffic deadlines can be met. However, many real-time applications also have additional requirements such as high throughput, high reliability, or energy efficiency. High-performance embedded systems communicating heterogeneous traffic with high bandwidth and strict timing requirements are in need of more efficient communication solutions, while wireless industrial applications, communicating control data, require support of reliability and guarantees of real-time predictability at the same time. To meet the requirements of high-performance embedded systems, this thesis work proposes two multi-wavelength high-speed passive optical networks. To enable reliable wireless industrial communications, a framework incorporating carefully scheduled retransmissions is developed. All solutions are based on a single-hop star topology, predictable Medium Access Control algorithms and Earliest Deadline First scheduling, centrally controlled by a master node. Further, real-time schedulability analysis is used as admission control policy to provide delay guarantees for hard real-time traffic. For high-performance embedded systems an optical star network with an Arrayed Waveguide Grating placed in the centre is suggested. The design combines spatial wavelength reuse with fixed-tuned and tuneable transceivers in the end nodes, enabling simultaneous transmission of both control and data traffic. This, in turn, permits efficient support of heterogeneous traffic with both hard and soft real-time constraints. By analyzing traffic dependencies in this multichannel network, and adapting the real-time schedulability analysis to incorporate these traffic dependencies, a considerable increase of the possible guaranteed throughput for hard real-time traffic can be obtained. Most industrial applications require using existing standards such as IEEE 802.11 or IEEE 802.15.4 for interoperability and cost efficiency. However, these standards do not provide predictable channel access, and thus real-time guarantees cannot be given. A framework is therefore developed, combining transport layer retransmissions with real-time analysis admission control, which has been adapted to consider retransmissions. It can be placed on top of many underlying communication technologies, exemplified in our work by the two aforementioned wireless standards. To enable a higher data rate than pure IEEE 802.15.4, but still maintaining its energy saving properties, two multichannel network architectures based on IEEE 802.15.4 and encompassing the framework are designed. The proposed architectures are evaluated in terms of reliability, utilization, delay, complexity, scalability and energy efficiency and it is concluded that performance is enhanced through redundancy in the time and frequency domains.
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Tenório, Marcos Mincov. "Metodologias para roteamento ótimo em redes de telecomunicações". Universidade Tecnológica Federal do Paraná, 2011. http://repositorio.utfpr.edu.br/jspui/handle/1/395.
Testo completoAbstract (sommario):
Fundação AraucáriaO gerenciamento do tráfego na Internet tornou-se essencial devido à grande utilização de serviços em rede nos últimos anos. Assim, para executar alguns serviços que demandam um certo grau de qualidade é necessário otimizar o uso de recursos existentes. Organizações mantenedoras de backbones são responsáveis por rotear o tráfego, utilizando protocolos que encaminham dados da origem ao destino. Um dos protocolos de roteamento mais utilizados mundialmente é o Open Shortest Path First (OSPF). A qualidade das rotas oferecidas pelo protocolo OSPF depende dos pesos atribuídos pelo operador de rede às ligações (enlaces). A determinação destes pesos depende dos critérios técnicos ou econômicos considerados necessários por parte da empresa provedora de serviços telemáticos. Nesta dissertação aborda-se o problema de rotear a demanda de tráfego na rede com o objetivo de oferecer uma qualidade de serviço satisfatória por meio de uma atribuição inteligente de pesos aos enlaces. O problema de atribuição de pesos (WSP), consiste em encontrar um conjunto de pesos OSPF que otimiza o desempenho da rede. Para solução deste problema, a literatura científica apresenta algoritmos que, na sua maioria, buscam equilibrar o tráfego na rede pelo ajuste correto da carga de cada enlace. Essa dissertação visa solucionar o WSP propondo uma nova abordagem que leva em consideração a perda de pacotes em caminhos origem-destino e a sobrecarga gerada em cada enlace. Também uma formulação estendida é proposta, permitindo a obtenção de um conjunto de pesos operacionais em ambientes normais e em ambientes onde ocorrem falhas de nós. A aplicação de duas heurísticas conhecidas, Simulated Annealing e Harmony Search, a este problema permite encontrar soluções satisfatórias para os critérios de desempenho especificados.
Internet traffic management becomes essential due the large use of the Internet the past decades. Balancing the use of existing IP resources improves the performance of services. Backbone manteiners are responsible for routing data that are sent along the network links from a source to a destination host. A routing protocol is used to perform this task. One of the most commonly used internal routing protocol is OSPF (Open Shortest Path First). The quality of the routes offered by the OSPF protocol mainly depends on weights that are assigned by the network operator to the links. The determination of these weights depends on technical or economic criteria deemed necessary by the ISPs. This master dissertation addresses the routing problem aiming at providing network quality of service by optimizing the weights assigned to links. The weight setting problem (WSP) corresponds to find a set of OSPF weights that optimize network performance. To solve this problem, the literature shows algorithms that mostly seek to balance the network traffic by correctly setting link loads. This work aims at solving WSP proposing a new approach that takes into account packet losses over origin-destination paths and link overhead. Also an extended formulation is proposed, to obtain a set of operating weights in normal environments and in environments where node failures can occur. The application of two well known heuristics, Simulated Annealing and Harmony Search, to this problem allows to find satisfactory solutions to the performance criteria specified.