"Handling Updates and Crashes in VoD Systems"

Though there have been several recent efforts to develop disk based video servers, these approaches have all ignored the topic of updates and disk server crashes. In this paper, we present a priority based model for building video servers that handle two classes of events: user events that could include enter, play, pause, rewind, fast-forward, exit, as well as system events such as insert, delete, server-down, server-up that correspond to uploading new movie blocks onto the disk(s), eliminating existing blocks from the disk(s), and/or experiencing a disk server crash. We will present algorithms to handle such events. Our algorithms are provably correct, and computable in polynomial time. Furthermore, we guarantee that under certain reasonable conditions, continuing clients experience jitter free presentations. We further justify the efficiency of our techniques with a prototype implementation and experimental results. (Also cross-referenced as UMIACS-TR-97-47

Kubernetes as an Availability Manager for Microservice Based Applications

The architectural style of microservices has been gaining popularity in recent years. In this architectural style, small and loosely coupled modules are deployed and scaled inde-pendently to compose cloud-native applications. Microservices are maintained and tested easily and are faster at startup time. However, to fully leverage from the benefits of the archi-tectural style of microservices, it is necessary to use technologies such as containerization. Therefore, in practice, microservices are containerized in order to remain isolated and light-weight and are orchestrated by orchestration platforms such as Kubernetes. Kubernetes is an open-source platform that defines a set of building blocks which collectively provide mecha-nisms for orchestrating containerized microservices. The move towards the architectural style of microservices is well underway and carrier-grade service providers are migrating their lega-cy applications to a microservice based architecture running on Kubernetes. However, service availability remains a concern. Service availability is measured as the percentage of time the service is provisioned. High Availability (HA) is a non-functional requirement for service availability of at least 99.999%. Although the characteristics of microservice based architec-tures naturally contribute to improving the availability, Kubernetes as an orchestration plat-form for microservices needs to be evaluated in terms of availability. Therefore, in this thesis, we identify possible architectures for deploying stateless and stateful microservice based ap-plications with Kubernetes and evaluate Kubernetes from the perspective of availability it provides for its managed applications. Our experiment’s results show that the healing capabili-ties of Kubernetes are not sufficient for providing high availability, especially for stateful ap-plications. Therefore, we propose a State Controller which integrates with Kubernetes and allows for state replication and automatic service redirection to the healthy microservice instance. We conduct experiments to evaluate our solution and compare the different archi-tectures from an availability perspective and scaling overhead. The results of our investiga-tions show that our solution improves the recovery time of stateful microservice based appli-cations by 55% and even up to 99% in certain cases

Value Creation in a QoE Environment

User behavior of multimedia services currently undergoes strong changes. This is reflected in several recent trends, e.g. the increase of rich media content consumption, preferences for more individual and personalized services and the higher sensitivity of end users for quality issues. These changes will eventually lead to strong changes in network traffic characteristics: rising congestion in peak times and less availability of bandwidth for the individual user. As a result, the quality as perceived by the end-user will decrease if network operators and service providers do not anticipate the required changes for the network. Measurable network requirements such as available video and speech quality, security and reliability are addressed by technologies that are commonly summed up in the Quality of Service (QoS) concept. However, the end-users' perception of quality is only reflected in the wider concept of Quality of Experience (QoE). This takes the measurable network requirements into account as well as customer needs, wants and preferences. For the implementation of QoE technologies several network components need to be added or changed resulting in high capital expenditures. Yet, it is not clear if these costs can be compensated with efficiency increases. Thus, new revenue streams for the network operator are necessary to incentivize investments in QoE technologies. In this paper we address four new value creation models that can serve as basis for more elaborated business models for network operators and other actors. We show how interest in QoE of the user, the content provider, the service provider and the advertiser induces new revenue streams. These models are embedded in five possible future QoE scenarios that reveal regulation, end user quality sensibility and end-to-end support as major issues for the future. --Business Models,Quality of Experience (QoE),Quality of Service (QoS),Value Creation

System analysis of a Peer-to-Peer Video-on-Demand architecture : Kangaroo

Architectural design and deployment of Peer-to-Peer Video-on-Demand (P2PVoD) systems which support VCR functionalities is attracting the interest of an increasing number of research groups within the scientific community; especially due to the intrinsic characteristics of such systems and the benefits that peers could provide at reducing the server load. This work focuses on the performance analysis of a P2P-VoD system considering user behaviors obtained from real traces together with other synthetic user patterns. The experiments performed show that it is feasible to achieve a performance close to the best possible. Future work will consider monitoring the physical characteristics of the network in order to improve the design of different aspects of a VoD system.El disseny arquitectònic i el desplegament de sistemes de Vídeo sota Demanda "Peer-to-Peer" que soporten funcionalitats VCR està captant l'interès d'un nombre creixent de grups de recerca a la comunitat científica, degut especialment a les característiques intrínsiques dels mencionats sistemes i als beneficis que els peers podrien proporcionar a la reducció de la càrrega en el servidor. Aquest treball tracta l'anàlisi del rendiment d'un sistema P2P-VoD considerant el comportament d'usuaris obtingut amb traçes reals i amb patrons sintètics. Els experiments realitzats mostren que és viable assolir un rendiment proper al cas més óptim. Com treball futur es considerarà la monitorització de les característiques físiques de la xarxa per a poder millorar el disseny dels diferents aspectes que formen un sistema de VoD.El diseño arquitectónico y el despliegue de sistemas de Video bajo Demanda "Peer-to-Peer" que soportan funcionalidades VCR está captando el interés de un número creciente de grupos de investigación dentro de la comunidad científica; especialmente debido a las características intrínsecas de tales sistemas y a los beneficios que los peers podrían proporcionar en la reducción de la carga en el servidor. Este trabajo se enfoca en el análisis de rendimiento de un sistema P2PVoD considerando el comportamiento de usuarios obtenido de trazas reales, junto a otros patrones sintéticos. Los experimentos realizados muestran que es viable lograr un rendimiento cercano al caso más óptimo. El trabajo futuro considerará la monitorización de las características físicas de la red para poder mejorar el diseño de los diferentes aspectos que conforman un sistema de VoD

Program Aging and Service Crash

Abstract: Program aging is a degradation of performance or functionality caused by resource depletion. The aging affects the cloud services which provide access to big data bank and computing resources. This suffers large budget and delays of defect removal, which requires other related solutions including renewal in the form of controlled restarts. Collection of various runtime metrics are more significant source for further study of detection and analysis of aging issues. This study highlights the method for detecting aging immediately after their introduction by runtime comparisons of different development scenarios. The study focuses on aging of program and service crash as a consequence

Performance Benchmark for Smart TV Platforms, Set-Top Boxes and Game Consoles

Cílem této práce je vytvořit nástroj pro vývoj aplikací  na určité minoritní platformy, primárně Smart TV a HbbTV. Ty jsou implementovány v klienském JavaScriptu. Cílovou skupinou jsou tedy vývojáři takových aplikací, nikoli koncoví uživatelé. Zmíněný nástroj bude mít za cíl zjednodušit a urychlit vývojové procesy, hlavně ladění výkonu aplikací.The purpose of this thesis is to create a tool for development of applications for certain minority platforms, primarily Smart TV and HbbTV. Those are implemented in a client-side JavaScript. Target group are hence the JavaScript developers, not the end-users. Said tool will target simplification and speed-up of development processes, mainly applications' performance tuning.

RETAIL HEALTH & SAFETY DIGITAL MANAGEMENT SYSTEM

Health and Safety procedures and documentations are one of the many tasks that need to be done by a small retail shop, they are also one of the most difficult things to manage daily as all those can build up during the day/week. Inside Health and Safety there are many subcategories that need to be administered (maintenances, trainings and checklists for example) which can be very overwhelming for any management team notably in small retail shops as they do not have the permanent personnel to be able to maintain an organised system. This project aims to create a management software to assist a business to conduct all those procedures in an easier and more efficient manner

Parallel replication for distributed video-on-demand systems.

Lie, Wai-Kwok Peter.Thesis (M.Phil.)--Chinese University of Hong Kong, 1997.Includes bibliographical references (leaves 79-83).Abstract --- p.iAcknowledgments --- p.iiChapter 1 --- Introduction --- p.1Chapter 2 --- Background & Related Work --- p.5Chapter 2.1 --- Early Work on Multimedia Servers --- p.6Chapter 2.2 --- Compression of Multimedia Data --- p.6Chapter 2.3 --- Multimedia File Systems --- p.7Chapter 2.4 --- Scheduling Support for Multimedia Systems --- p.8Chapter 2.5 --- Inter-media Synchronization --- p.9Chapter 2.6 --- Related Work on Replication in VOD Systems --- p.9Chapter 3 --- System Model --- p.12Chapter 4 --- Replication Methodology --- p.15Chapter 4.1 --- Replication Triggering Policy --- p.16Chapter 4.2 --- Source & Target Nodes Selection Policies --- p.17Chapter 4.3 --- Replication Policies --- p.18Chapter 4.3.1 --- Policy 1: Injected Sequential Replication --- p.20Chapter 4.3.2 --- Policy 2: Piggybacked Sequential Replication --- p.22Chapter 4.3.3 --- Policy 3: Injected Parallel Replication --- p.25Chapter 4.3.4 --- Policy 4: Piggybacked Parallel Replication --- p.28Chapter 4.3.5 --- Policy 5: Injected & Piggybacked Parallel Replication --- p.34Chapter 4.3.6 --- Policy 6: Multi-Source Injected & Piggybacked Parallel Replication --- p.36Chapter 4.4 --- Dereplication Policy --- p.37Chapter 5 --- Distributed Architecture for VOD Server --- p.39Chapter 5.1 --- Server Node --- p.40Chapter 5.2 --- Movie Manager --- p.42Chapter 5.3 --- Metadata Manager --- p.42Chapter 5.4 --- Protocols for Distributed VOD Architecture --- p.43Chapter 5.4.1 --- Protocol for Servicing New Customers --- p.43Chapter 5.4.2 --- Protocol for Servicing Existing Customers --- p.45Chapter 5.4.3 --- Protocol for Single/Multi-Source Injected & Parallel Replication --- p.46Chapter 5.4.4 --- Protocol for Dereplication --- p.48Chapter 5.5 --- Failure Handling --- p.49Chapter 5.5.1 --- Handling of Server Node Failures --- p.50Chapter 5.5.2 --- Handling of Movie Manager Failures --- p.52Chapter 6 --- Results --- p.55Chapter 6.1 --- Performance Metric --- p.56Chapter 6.2 --- Simulation Environment --- p.58Chapter 6.3 --- Results of Experiments without Dereplication --- p.59Chapter 6.3.1 --- Comparison of Different Replication Policies --- p.60Chapter 6.3.2 --- Effect of Early Acceptance/Migration --- p.61Chapter 6.3.3 --- Answer to the Resources Consumption Tradeoff issue --- p.62Chapter 6.3.4 --- Effect of Varying Movie Popularity Skewness --- p.64Chapter 6.3.5 --- Effect of Varying Replication Threshold --- p.64Chapter 6.3.6 --- Comparison of Different Target Node Selection Policies --- p.65Chapter 6.4 --- Overall Impact of Dynamic Replication --- p.66Chapter 7 --- Comparison with BSR-based Policy --- p.71Chapter 8 --- Conclusions --- p.75Chapter 8.1 --- Summary --- p.75Chapter 8.2 --- Future Research Directions --- p.76Bibliography --- p.7

Video-on-Demand over Internet: a survey of existing systems and solutions

Video-on-Demand is a service where movies are delivered to distributed users with low delay and free interactivity. The traditional client/server architecture experiences scalability issues to provide video streaming services, so there have been many proposals of systems, mostly based on a peer-to-peer or on a hybrid server/peer-to-peer solution, to solve this issue. This work presents a survey of the currently existing or proposed systems and solutions, based upon a subset of representative systems, and defines selection criteria allowing to classify these systems. These criteria are based on common questions such as, for example, is it video-on-demand or live streaming, is the architecture based on content delivery network, peer-to-peer or both, is the delivery overlay tree-based or mesh-based, is the system push-based or pull-based, single-stream or multi-streams, does it use data coding, and how do the clients choose their peers. Representative systems are briefly described to give a summarized overview of the proposed solutions, and four ones are analyzed in details. Finally, it is attempted to evaluate the most promising solutions for future experiments. Résumé La vidéo à la demande est un service où des films sont fournis à distance aux utilisateurs avec u

Flexi-WVSNP-DASH: A Wireless Video Sensor Network Platform for the Internet of Things

abstract: Video capture, storage, and distribution in wireless video sensor networks (WVSNs) critically depends on the resources of the nodes forming the sensor networks. In the era of big data, Internet of Things (IoT), and distributed demand and solutions, there is a need for multi-dimensional data to be part of the Sensor Network data that is easily accessible and consumable by humanity as well as machinery. Images and video are expected to become as ubiquitous as is the scalar data in traditional sensor networks. The inception of video-streaming over the Internet, heralded a relentless research for effective ways of distributing video in a scalable and cost effective way. There has been novel implementation attempts across several network layers. Due to the inherent complications of backward compatibility and need for standardization across network layers, there has been a refocused attention to address most of the video distribution over the application layer. As a result, a few video streaming solutions over the Hypertext Transfer Protocol (HTTP) have been proposed. Most notable are Apple’s HTTP Live Streaming (HLS) and the Motion Picture Experts Groups Dynamic Adaptive Streaming over HTTP (MPEG-DASH). These frameworks, do not address the typical and future WVSN use cases. A highly flexible Wireless Video Sensor Network Platform and compatible DASH (WVSNP-DASH) are introduced. The platform's goal is to usher video as a data element that can be integrated into traditional and non-Internet networks. A low cost, scalable node is built from the ground up to be fully compatible with the Internet of Things Machine to Machine (M2M) concept, as well as the ability to be easily re-targeted to new applications in a short time. Flexi-WVSNP design includes a multi-radio node, a middle-ware for sensor operation and communication, a cross platform client facing data retriever/player framework, scalable security as well as a cohesive but decoupled hardware and software design.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201