292 research outputs found
A framework for realistic real-time walkthroughs in a VR distributed environment
Virtual and augmented reality (VR/AR) are
increasingly being used in various business scenarios and
are important driving forces in technology development.
However the usage of these technologies in the home
environment is restricted due to several factors including
lack of low-cost (from the client point of view) highperformance
solutions. In this paper we present a general
client/server rendering architecture based on Real-Time
concepts, including support for a wide range of client
platforms and applications. The idea of focusing on the
real-time behaviour of all components involved in
distributed IP-based VR scenarios is new and has not been
addressed before, except for simple sub-solutions. This is
considered as “the most significant problem with the IP
environment” [1]. Thus, the most important contribution of
this research will be the holistic approach, in which
networking, end-systems and rendering aspects are
integrated into a cost-effective infrastructure for building
distributed real-time VR applications on IP-based
networks
QoS Contract Negotiation in Distributed Component-Based Software
Currently, several mature and commercial component models (for e.g. EJB, .NET, COM+) exist on the market. These technologies were designed largely for applications with business-oriented non-functional requirements such as data persistence, confidentiality, and transactional support. They provide only limited support for the development of components and applications with non-functional properties (NFPs) like QoS (e.g. throughput, response time). The integration of QoS into component infrastructure requires among other things the support of components’ QoS contract specification, negotiation, adaptation, etc. This thesis focuses on contract negotiation. For applications in which the consideration of non-functional properties (NFPs) is essential (e.g. Video-on-Demand, eCommerce), a component-based solution demands the appropriate composition of the QoS contracts specified at the different ports of the collaborating components. The ports must be properly connected so that the QoS level required by one is matched by the QoS level provided by the other. Generally, QoS contracts of components depend on run-time resources (e.g. network bandwidth, CPU time) or quality attributes to be established dynamically and are usually specified in multiple QoS-Profiles. QoS contract negotiation enables the selection of appropriate concrete QoS contracts between collaborating components. In our approach, the component containers perform the contract negotiation at run-time. This thesis addresses the QoS contract negotiation problem by first modelling it as a constraint satisfaction optimization problem (CSOP). As a basis for this modelling, the provided and required QoS as well as resource demand are specified at the component level. The notion of utility is applied to select a good solution according to some negotiation goal (e.g. user’s satisfaction). We argue that performing QoS contract negotiation in multiple phases simplifies the negotiation process and makes it more efficient. Based on such classification, the thesis presents heuristic algorithms that comprise coarse-grained and fine-grained negotiations for collaborating components deployed in distributed nodes in the following scenarios: (i) single-client - single-server, (ii) multiple-clients, and (iii) multi-tier scenarios. To motivate the problem as well as to validate the proposed approach, we have examined three componentized distributed applications. These are: (i) video streaming, (ii) stock quote, and (iii) billing (to evaluate certain security properties). An experiment has been conducted to specify the QoS contracts of the collaborating components in one of the applications we studied. In a run-time system that implements our algorithm, we simulated different behaviors concerning: (i) user’s QoS requirements and preferences, (ii) resource availability conditions concerning the client, server, and network bandwidth, and (iii) the specified QoS-Profiles of the collaborating components. Under various conditions, the outcome of the negotiation confirms the claim we made with regard to obtaining a good solution
QUALINET white paper on definitions of Immersive Media Experience (IMEx)
With the coming of age of virtual/augmented reality and interactive media,
numerous definitions, frameworks, and models of immersion have emerged across
different fields ranging from computer graphics to literary works. Immersion is
oftentimes used interchangeably with presence as both concepts are closely
related. However, there are noticeable interdisciplinary differences regarding
definitions, scope, and constituents that are required to be addressed so that
a coherent understanding of the concepts can be achieved. Such consensus is
vital for paving the directionality of the future of immersive media
experiences (IMEx) and all related matters.
The aim of this white paper is to provide a survey of definitions of
immersion and presence which leads to a definition of immersive media
experience (IMEx). The Quality of Experience (QoE) for immersive media is
described by establishing a relationship between the concepts of QoE and IMEx
followed by application areas of immersive media experience. Influencing
factors on immersive media experience are elaborated as well as the assessment
of immersive media experience. Finally, standardization activities related to
IMEx are highlighted and the white paper is concluded with an outlook related
to future developments
A reduced reference video quality assessment method for provision as a service over SDN/NFV-enabled networks
139 p.The proliferation of multimedia applications and services has generarted a noteworthy upsurge in network traffic regarding video content and has created the need for trustworthy service quality assessment methods. Currently, predominent position among the technological trends in telecommunication networkds are Network Function Virtualization (NFV), Software Defined Networking (SDN) and 5G mobile networks equipped with small cells. Additionally Video Quality Assessment (VQA) methods are a very useful tool for both content providers and network operators, to understand of how users perceive quality and this study the feasibility of potential services and adapt the network available resources to satisfy the user requirements
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