QoP-Driven Scheduling for MPEG Video Decoding

MPEG video decoding algorithm has been embedded into many consumer electronic products. In this paper, we demonstrate that the completion ratio (CR) does not represent well the quality of presentation (QoP) of MPEG video. We then propose a new QoP metric, which 1) is based on frame completion ratio but 2) differentiates firm and soft deadlines and also 3) considers the frame dependency. We show that, on a set of simulated MPEG movies, the proposed QoP metric measures the QoP of the movies much better than the completion ratio. We then present a set of online scheduling algorithms that enhance QoP significantly, particularly for overloaded systems

QOS-DRIVEN SCHEDULING FOR MULTIMEDIA APPLICATIONS

Multimedia applications have intrinsic quality of service (QoS) requirements that may not be captured by the simple traditional completion ratio model. We have proposed a new quantitative QoS metric based on task completion ratio while differentiating firm and soft deadlines and taking data dependency into consideration. Using the decoding of MPEG movies as an example, we have shown that the proposed QoS metric is much better than completion ratio in measuring the quality of presentation (QoP) of the movies. Based on the new QoS metric, we present a set of new online algorithms that outperform popular scheduling algorithms (such as EDF, FCFS, and LETF) and enhance QoP significantly, particularly when the system is overloaded. All the proposed online algorithms have low computation overhead and can be easily integrated into real-time operating systems to improve multimedia embedded system’s performance and/or to save system resources

Providing QoS with Reduced Energy Consumption via Real-Time Voltage Scaling on Embedded Systems

Low energy consumption has emerged as one of the most important design objectives for many modern embedded systems, particularly the battery-operated PDAs. For some soft real-time applications such as multimedia applications, occasional deadline misses can be tolerated. How to leverage this feature to save more energy while still meeting the user required quality of service (QoS) is the research topic this thesis focuses on. We have proposed a new probabilistic design methodology, a set of energy reduction techniques for single and multiple processor systems by using dynamic voltage scaling (DVS), the practical solutions to voltage set-up problem for multiple voltage DVS system, and a new QoS metric. Most present design space exploration techniques, which are based on application's worst case execution time, often lead to over-designing systems. We have proposed the probabilistic design methodology for soft real-time embedded systems by using detailed execution time information in order to reduce the system resources while delivering the user required QoS probabilistically. One important phase in the probabilistic design methodology is the offline/online resource management. As an example, we have proposed a set of energy reduction techniques by employing DVS techniques to exploit the slacks arising from the tolerance to deadline misses for single and multiple processor systems while meeting the user required completion ratio statistically. Multiple-voltage DVS system is predicted as the future low-power system by International Technology Roadmap for Semiconductors (ITRS). In order to find the best way to employ DVS, we have formulated the voltage set-up problem and provided its practical solutions that seek the most energy efficient voltage setting for the design of multiple-voltage DVS systems. We have also presented a case study in designing energy-efficient dual voltage soft real-time system with (m, k)-firm deadline guarantee. Although completion ratio is widely used as a QoS metric, it can only be applied to the applications with independent tasks. We have proposed a new QoS metric that differentiates firm and soft deadlines and considers the task dependency as well. Based on this new metric, we have developed a set of online scheduling algorithms that enhance quality of presentation (QoP) significantly, particularly for overloaded systems

Video Classification and Adaptive QoP/QoS Control for Multiresolution Video Applications on IPTV

With the development of heterogeneous networks and video coding standards, multiresolution video applications over networks become important. It is critical to ensure the service quality of the network for time-sensitive video services. Worldwide Interoperability for Microwave Access (WIMAX) is a good candidate for delivering video signals because through WIMAX the delivery quality based on the quality-of-service (QoS) setting can be guaranteed. The selection of suitable QoS parameters is, however, not trivial for service users. Instead, what a video service user really concerns with is the video quality of presentation (QoP) which includes the video resolution, the fidelity, and the frame rate. In this paper, we present a quality control mechanism in multiresolution video coding structures over WIMAX networks and also investigate the relationship between QoP and QoS in end-to-end connections. Consequently, the video presentation quality can be simply mapped to the network requirements by a mapping table, and then the end-to-end QoS is achieved. We performed experiments with multiresolution MPEG coding over WIMAX networks. In addition to the QoP parameters, the video characteristics, such as, the picture activity and the video mobility, also affect the QoS significantly

Cross-Layer Optimization for Video-streaming Transmission with QoS over Ad Hoc Networks: A Holistic Approach

In this paper we present ViStA-XL, a Cross-Layer (XL) design aiming to optimize the overall performance of videostreaming services over Mobile Ad Hoc Networks (MANETs). The idea relies on applying optimization strategies to different network layers in a holistic way. In ViStA-XL, a real-time Optimizer (XLO) periodically gathers information of the state of node and network from different layers of the stack of protocols, takes optimization decisions, and then modifies some parameters of the protocols accordingly. In addition, our proposal exploits path diversity through MM-DSR (Multipath MultimediaDynamic Source Routing) protocol as a means to reinforce the Quality of Service (QoS) provision to multi-layer encoded videostreaming applications, by protecting the most important video information packets, balancing the load and decreasing the endto-end delay. To show the advantages of our approach, we have developed and tested an algorithm based on ViStA-XL. Simulation results show that our proposed network design can improve the performance of video-streaming transmissions over MANETs in spite of frequent changes in network and node operating conditions

An adaptive framework for end-to-end quality of service management

Ph.DDOCTOR OF PHILOSOPH

Interoperability of wireless communication technologies in hybrid networks: Evaluation of end-to-end interoperability issues and quality of service requirements

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Hybrid Networks employing wireless communication technologies have nowadays brought closer the vision of communication “anywhere, any time with anyone”. Such communication technologies consist of various standards, protocols, architectures, characteristics, models, devices, modulation and coding techniques. All these different technologies naturally may share some common characteristics, but there are also many important differences. New advances in these technologies are emerging very rapidly, with the advent of new models, characteristics, protocols and architectures. This rapid evolution imposes many challenges and issues to be addressed, and of particular importance are the interoperability issues of the following wireless technologies: Wireless Fidelity (Wi-Fi) IEEE802.11, Worldwide Interoperability for Microwave Access (WiMAX) IEEE 802.16, Single Channel per Carrier (SCPC), Digital Video Broadcasting of Satellite (DVB-S/DVB-S2), and Digital Video Broadcasting Return Channel through Satellite (DVB-RCS). Due to the differences amongst wireless technologies, these technologies do not generally interoperate easily with each other because of various interoperability and Quality of Service (QoS) issues. The aim of this study is to assess and investigate end-to-end interoperability issues and QoS requirements, such as bandwidth, delays, jitter, latency, packet loss, throughput, TCP performance, UDP performance, unicast and multicast services and availability, on hybrid wireless communication networks (employing both satellite broadband and terrestrial wireless technologies). The thesis provides an introduction to wireless communication technologies followed by a review of previous research studies on Hybrid Networks (both satellite and terrestrial wireless technologies, particularly Wi-Fi, WiMAX, DVB-RCS, and SCPC). Previous studies have discussed Wi-Fi, WiMAX, DVB-RCS, SCPC and 3G technologies and their standards as well as their properties and characteristics, such as operating frequency, bandwidth, data rate, basic configuration, coverage, power, interference, social issues, security problems, physical and MAC layer design and development issues. Although some previous studies provide valuable contributions to this area of research, they are limited to link layer characteristics, TCP performance, delay, bandwidth, capacity, data rate, and throughput. None of the studies cover all aspects of end-to-end interoperability issues and QoS requirements; such as bandwidth, delay, jitter, latency, packet loss, link performance, TCP and UDP performance, unicast and multicast performance, at end-to-end level, on Hybrid wireless networks. Interoperability issues are discussed in detail and a comparison of the different technologies and protocols was done using appropriate testing tools, assessing various performance measures including: bandwidth, delay, jitter, latency, packet loss, throughput and availability testing. The standards, protocol suite/ models and architectures for Wi-Fi, WiMAX, DVB-RCS, SCPC, alongside with different platforms and applications, are discussed and compared. Using a robust approach, which includes a new testing methodology and a generic test plan, the testing was conducted using various realistic test scenarios on real networks, comprising variable numbers and types of nodes. The data, traces, packets, and files were captured from various live scenarios and sites. The test results were analysed in order to measure and compare the characteristics of wireless technologies, devices, protocols and applications. The motivation of this research is to study all the end-to-end interoperability issues and Quality of Service requirements for rapidly growing Hybrid Networks in a comprehensive and systematic way. The significance of this research is that it is based on a comprehensive and systematic investigation of issues and facts, instead of hypothetical ideas/scenarios or simulations, which informed the design of a test methodology for empirical data gathering by real network testing, suitable for the measurement of hybrid network single-link or end-to-end issues using proven test tools. This systematic investigation of the issues encompasses an extensive series of tests measuring delay, jitter, packet loss, bandwidth, throughput, availability, performance of audio and video session, multicast and unicast performance, and stress testing. This testing covers most common test scenarios in hybrid networks and gives recommendations in achieving good end-to-end interoperability and QoS in hybrid networks. Contributions of study include the identification of gaps in the research, a description of interoperability issues, a comparison of most common test tools, the development of a generic test plan, a new testing process and methodology, analysis and network design recommendations for end-to-end interoperability issues and QoS requirements. This covers the complete cycle of this research. It is found that UDP is more suitable for hybrid wireless network as compared to TCP, particularly for the demanding applications considered, since TCP presents significant problems for multimedia and live traffic which requires strict QoS requirements on delay, jitter, packet loss and bandwidth. The main bottleneck for satellite communication is the delay of approximately 600 to 680 ms due to the long distance factor (and the finite speed of light) when communicating over geostationary satellites. The delay and packet loss can be controlled using various methods, such as traffic classification, traffic prioritization, congestion control, buffer management, using delay compensator, protocol compensator, developing automatic request technique, flow scheduling, and bandwidth allocation

Open Profiling of Quality: A Mixed Methods Research Approach for Audiovisual Quality Evaluations

Den Anforderungen der Konsumenten gerecht zu werden und ihnen eine immer besser werdende Quality of Experience zu bieten, ist eine der großen Herausforderungen jeder Neuentwicklung im Bereich der Multimediasysteme. Doch proportional zur technischen Komplexität neuer Systeme, in denen Komponenten unterschiedlicher Technologien zu neuen System wie zum Beispiel mobilem 3D-Fernsehen verschmolzen werden, steigt auch die Frage, wie eine optimierte Quality of Experience eigentlich zu erreichen ist. Daher werden seit langer Zeit Nutzertests zur subjektiven Qualitätsbewertung durchgeführt. Deren Ziel über den gesamten Entwcklungsprozesses ist es, die kritischen Komponenten des Systems mit so wenig wie möglich wahrnehmbarem Einfluss auf diewahrgenommene Qualität des Nutzers zu optimieren. Bereits seit den 1970er Jahren werden hierfür Leitfäden verschiedener Standardisierungsgremien zur Verfügung gestellt, in denen unterschiedliche Evaluationsmethoden definiert sind, um die wahrgenommene Gesamtqualität des Systems mit Hilfe von Skalen quantitativ evaluieren zu können. Aktuelle Ansätze erweitern diese klassische Methoden um Sichtweise, die über die klassische Evaluation hedonistischer Gesamtqualität hinausgehen, um das Wissen über individuell zugrundeliegende Qualitätsfaktoren zu erweitern.Die vorliegende Dissertation verfolgt dabei zwei Ziele. Zum einen soll eine audiovisuelle Evaluationsmethode entwickelt werden, die eine kombinierte Analyse quantitativer und qualitativer Daten ermöglicht, um eine Verknüpfung hedonistischer Qualität und zugrundeliegender Qualitätsfaktoren zu ermöglichen. Weiter soll diese Methode innerhalb des Gebiets der mobiler 3DTV-Systeme erprobt und validiert werden.Open Profiling of Quality (OPQ) als Evaluationsmethode kombiniert quantitative Evaluation wahrgenommener Gesamtqualität und deskriptive, sensorische Analyse zur Erhebung individueller Qualitätsfaktoren. Die Methode ist für Erhebungen mit naiven Probanden geeignet. OPQ wurde unter besonderer Beachtung von Validität und Reliabilität in einem konstruktivem Ansatz entwickelt und in einer Folge von Studien während der Entwicklung eines mobilem 3DTV-Systems mit über 300 Probanden angewendet. Die Ergebnisse dieser Studien unterstreichen die sich ergänzenden Ergebnisse quantitativer und sensorischer Analysen.Neben der Entwicklung von OPQ werden in der vorliegenden Arbeit weitere Ansätze sensorischer Analyse präsentiert und miteinander verglichen. Gerade dieser Vergleich ist ein wichtiger Bestandteil der Validierung der OPQ-Methode. Um die Stärken und Schwächen jeder Methode ganzheitlich erfassen und vergleichen zu können, wurde hierfür ein Methodenvergleichsmodell entwickelt und operationalisiert, das den methodischen Beitrag der Arbeit vervollständigtTo meet the requirements of consumers and to provide them with a greater quality of experience than existing systems do is a key issue for the success of modern multimedia systems. However, the question about an optimized quality of experience becomes more and more complex as technological systems are evolving and several systems are merged into new ones, e.g. systems for mobile 3D television and video. To be able to optimize critical components of a system under development with as little perceptual errors as possible, user studies are conducted throughout the whole process. A variety of research methods for different purposes have been provided by standardization bodies since the 1970s. These methods allow researchers to evaluate the hedonic excellence of a set of test stimuli. However, a broader view to quality has been taken recently to be able to evaluate quality beyond its hedonic excellence to obtain a greater knowledge about perceived quality and its subjective quality factors that impact on the user.The goal of this thesis is twofold. The primary goal is the development of a validated mixed methods research approach for audiovisual quality evaluations. The method shall allow collecting quantitative and descriptive data during the experiment to combine evaluation of hedonic excellence and the elicitation of underlying subjective quality factors. The second goal is the application of the developed method within a series of studies in the domain of mobile 3D video and television to show its applicability.Open Profiling of Quality (OPQ) is a mixed-methods research approach which combines a quantitative, psychoperceptual evaluation of hedonic excellence and a descriptive sensory analysis of underlying quality factors based on naive participants' individual vocabulary. This combination allows defining the excellence of overall quality, understanding the characteristics of quality perception, and, eventually, constructing a link between preferences and quality attributes. The method was developed under constructive research with respect to validity and reliability of test results. A series of quality evaluation studies with more than 300 test participants was conducted along different critical components of a system for optimized mobile 3DTV content delivery over DVB-H.The results complemented each other, and, even more importantly, quantitative quality preferences were explained by sensory descriptions in all studies. Beyond the development of OPQ, the thesis proposes further research approaches, e.g. a conventional profiling in which OPQ's individual vacobulary is substituted by a fixed set of Quality ofExperience components or Descriptive Sorted Napping which combines a sorting task and a short post-task interview. All approaches are compared to Open ProVling of Quality at the end of the thesis. To be able to holistically contrast strengths and weaknesses of each method, a comparison model for audiovisual evaluation methods was developed and a Vrst conceptual operationalization of the model was applied in the comparison

Interoperability of wireless communication technologies in hybrid networks : evaluation of end-to-end interoperability issues and quality of service requirements

Hybrid Networks employing wireless communication technologies have nowadays brought closer the vision of communication “anywhere, any time with anyone”. Such communication technologies consist of various standards, protocols, architectures, characteristics, models, devices, modulation and coding techniques. All these different technologies naturally may share some common characteristics, but there are also many important differences. New advances in these technologies are emerging very rapidly, with the advent of new models, characteristics, protocols and architectures. This rapid evolution imposes many challenges and issues to be addressed, and of particular importance are the interoperability issues of the following wireless technologies: Wireless Fidelity (Wi-Fi) IEEE802.11, Worldwide Interoperability for Microwave Access (WiMAX) IEEE 802.16, Single Channel per Carrier (SCPC), Digital Video Broadcasting of Satellite (DVB-S/DVB-S2), and Digital Video Broadcasting Return Channel through Satellite (DVB-RCS). Due to the differences amongst wireless technologies, these technologies do not generally interoperate easily with each other because of various interoperability and Quality of Service (QoS) issues. The aim of this study is to assess and investigate end-to-end interoperability issues and QoS requirements, such as bandwidth, delays, jitter, latency, packet loss, throughput, TCP performance, UDP performance, unicast and multicast services and availability, on hybrid wireless communication networks (employing both satellite broadband and terrestrial wireless technologies). The thesis provides an introduction to wireless communication technologies followed by a review of previous research studies on Hybrid Networks (both satellite and terrestrial wireless technologies, particularly Wi-Fi, WiMAX, DVB-RCS, and SCPC). Previous studies have discussed Wi-Fi, WiMAX, DVB-RCS, SCPC and 3G technologies and their standards as well as their properties and characteristics, such as operating frequency, bandwidth, data rate, basic configuration, coverage, power, interference, social issues, security problems, physical and MAC layer design and development issues. Although some previous studies provide valuable contributions to this area of research, they are limited to link layer characteristics, TCP performance, delay, bandwidth, capacity, data rate, and throughput. None of the studies cover all aspects of end-to-end interoperability issues and QoS requirements; such as bandwidth, delay, jitter, latency, packet loss, link performance, TCP and UDP performance, unicast and multicast performance, at end-to-end level, on Hybrid wireless networks. Interoperability issues are discussed in detail and a comparison of the different technologies and protocols was done using appropriate testing tools, assessing various performance measures including: bandwidth, delay, jitter, latency, packet loss, throughput and availability testing. The standards, protocol suite/ models and architectures for Wi-Fi, WiMAX, DVB-RCS, SCPC, alongside with different platforms and applications, are discussed and compared. Using a robust approach, which includes a new testing methodology and a generic test plan, the testing was conducted using various realistic test scenarios on real networks, comprising variable numbers and types of nodes. The data, traces, packets, and files were captured from various live scenarios and sites. The test results were analysed in order to measure and compare the characteristics of wireless technologies, devices, protocols and applications. The motivation of this research is to study all the end-to-end interoperability issues and Quality of Service requirements for rapidly growing Hybrid Networks in a comprehensive and systematic way. The significance of this research is that it is based on a comprehensive and systematic investigation of issues and facts, instead of hypothetical ideas/scenarios or simulations, which informed the design of a test methodology for empirical data gathering by real network testing, suitable for the measurement of hybrid network single-link or end-to-end issues using proven test tools. This systematic investigation of the issues encompasses an extensive series of tests measuring delay, jitter, packet loss, bandwidth, throughput, availability, performance of audio and video session, multicast and unicast performance, and stress testing. This testing covers most common test scenarios in hybrid networks and gives recommendations in achieving good end-to-end interoperability and QoS in hybrid networks. Contributions of study include the identification of gaps in the research, a description of interoperability issues, a comparison of most common test tools, the development of a generic test plan, a new testing process and methodology, analysis and network design recommendations for end-to-end interoperability issues and QoS requirements. This covers the complete cycle of this research. It is found that UDP is more suitable for hybrid wireless network as compared to TCP, particularly for the demanding applications considered, since TCP presents significant problems for multimedia and live traffic which requires strict QoS requirements on delay, jitter, packet loss and bandwidth. The main bottleneck for satellite communication is the delay of approximately 600 to 680 ms due to the long distance factor (and the finite speed of light) when communicating over geostationary satellites. The delay and packet loss can be controlled using various methods, such as traffic classification, traffic prioritization, congestion control, buffer management, using delay compensator, protocol compensator, developing automatic request technique, flow scheduling, and bandwidth allocation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

MS IPTV audit collection services

Tese de mestrado em Segurança Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2011Microsoft Mediaroom Internet Protocol Television (MS IPTV), uma plataforma de televisão digital, levou o conceito de televisão a uma dimensão totalmente nova. MS IPTV é um sistema onde o serviço de televisão digital é entregue aos clientes usando Internet Protocol (IP), através de uma conexão de banda larga. Com o advento do IPTV começaram a aparecer novas situações relacionadas com a segurança da televisão, uma vez que, a infra-estrutura começou a ganhar complexidade e exposição a uma série de novos riscos. Por esta razão, a segurança numa infra-estrutura de MS IPTV não é apenas mais uma funcionalidade, mas sim uma necessidade. Podemos mesmo dizer que hoje em dia é obrigatório aguçar o engenho para estar um passo à frente dos atacantes, uma vez que estes estão sempre à espera de uma brecha, para comprometer os sistemas. Uma infra-estrutura como o MS IPTV armazena por omissão dados relativos ao comportamento dos utilizadores ao nível dos logs, no entanto esta informação só se torna relevante se puder ser consultada e analisada com o objetivo de proporcionar uma compreensão a alto nível sobre os diferentes padrões que estão a ocorrer nos servidores ou no comportamento dos utilizadores, uma tarefa que envolve poderosas técnicas de data parsing. A tese apresenta uma abordagem que combina técnicas de data parsing, a fim de analisar os logs relevantes da infra-estrutura de MS IPTV, com o objetivo principal de aumentar a segurança através da investigação dos tipos de informações adicionais que pode ser extraída. Tentámos assim entender se é possível determinar que tipos de ataques estão a ser perpetrados contra a infra-estrutura MS IPTV, com base na análise dos logs. Como o foco central desta tese está no diagnóstico, propomos uma abordagem para descobrir ataques, onde os logs são verificados para identificar grupos coerentes de ocorrências susceptíveis de constituir ataques que apelidámos de padrões. Nos testes, verificámos que a nossa abordagem consegue bons resultados na descoberta de ataques. Os resultados obtidos têm a vantagem adicional de poderem ser integrados na ferramenta de monitorização utilizada pelas equipas de operação dos sistemas da Portugal Telecom, o System Center Operations Manager (SCOM).Microsoft Mediaroom Internet Protocol TeleVision (MS IPTV), one of the platforms for digital TV, took television to an all new dimension level. MS IPTV is described as a system where a digital television service is delivered to consumers using the Internet Protocol over a broadband connection. Since the infrastructure started to gain complexity and exposure to a number of new risks, never envisaged situations related to television security started to appear. For this reason, MS IPTV security is not only a great asset, but also a necessity. Nowadays it is mandatory to sharpen the wit to get ahead of attackers, who are always waiting for a breach to compromise our systems. MS IPTV log servers collect information about user and system behavior. However, this information only becomes relevant if it can be queried and analyzed with the purpose of providing high-level understanding about the different patterns. This task must comprise powerful data parsing techniques, since MS IPTV is able to generate close to one terabyte of logs per day. This thesis presents an approach that combines data parsing techniques in order to analyze relevant MS IPTV logs, with the main objective to increase security through the investigation of what type of additional information can be extracted from the server log files of a MS IPTV platform. The thesis focus is on diagnosis, trying to understand if it is possible to determine what type of attacks are being perpetrated against the MS IPTV infrastructure. We propose an approach for discovering attacks, where the application logs are scanned to identify coherent groups of occurrences that we call patterns, which are likely to constitute attacks. Our results showed that our approach achieves good results in discovering potential attacks. Our output results can be integrated into the MS IPTV monitoring system tool SCOM (System Center Operations Manager), which is an additional advantage over the other monitoring and log management systems