4,604 research outputs found
Virtual Audio - Three-Dimensional Audio in Virtual Environments
Three-dimensional interactive audio has a variety ofpotential uses in human-machine interfaces. After lagging seriously
behind the visual components, the importance of sound is now becoming
increas-ingly accepted.
This paper mainly discusses background and techniques to implement
three-dimensional audio in computer interfaces. A case study of a
system for three-dimensional audio, implemented by the author, is
described in great detail. The audio system was moreover integrated
with a virtual reality system and conclusions on user tests and use
of the audio system is presented along with proposals for future work
at the end of the paper.
The thesis begins with a definition of three-dimensional audio and a
survey on the human auditory system to give the reader the needed
knowledge of what three-dimensional audio is and how human auditory
perception works
Modeling a distributed Heterogeneous Communication System using Parametric Timed Automata
In this report, we study the application of the Parametric Timed Automata(PTA) tool to a concrete case of a distributed Heterogeneous Communication System (HCS). The description and requirements of HCS are presented and the system modeling is explained carefully. The system models are developed in UPPAAL and validated by different test cases. Part of the system models are then converted into parametric timed automata and the schedulability checking is run to produce the schedulability regions
A Basic Result on the Superposition of Arrival Processes in Deterministic Networks
Time-Sensitive Networking (TSN) and Deterministic Networking (DetNet) are
emerging standards to enable deterministic, delay-critical communication in
such networks. This naturally (re-)calls attention to the network calculus
theory (NC), since a rich set of results for delay guarantee analysis have
already been developed there. One could anticipate an immediate adoption of
those existing network calculus results to TSN and DetNet. However, the
fundamental difference between the traffic specification adopted in TSN and
DetNet and those traffic models in NC makes this difficult, let alone that
there is a long-standing open challenge in NC. To address them, this paper
considers an arrival time function based max-plus NC traffic model. In
particular, for the former, the mapping between the TSN / DetNet and the NC
traffic model is proved. For the latter, the superposition property of the
arrival time function based NC traffic model is found and proved. Appealingly,
the proved superposition property shows a clear analogy with that of a
well-known counterpart traffic model in NC. These results help make an
important step towards the development of a system theory for delay guarantee
analysis of TSN / DetNet networks
Experimental study and modelling of Networked Virtual Environment server traffic
The paradigm of virtual world environment arises
as an useful tool in diverse fields such as e-Health or education,
where they provide a new way of communication and interaction
with end users. Networking capabilities play an important role
in these systems, which motivates the study and understanding
of the gaming network traffic. The present work focuses on Open
Wonderland, a system that provides the basis for the development
of Networked Virtual Environments with educational or health
purposes. The goal of this paper is defining a testing environment
and modelling the behaviour of the outgoing network traffic at
the server side.Ministerio de Industria, Comercio y Turismo AAL-010000-2012-10Ministerio de Ciencia e Innovación TEC2009-10639-C04-0
Video Tester -- A multiple-metric framework for video quality assessment over IP networks
This paper presents an extensible and reusable framework which addresses the
problem of video quality assessment over IP networks. The proposed tool
(referred to as Video-Tester) supports raw uncompressed video encoding and
decoding. It also includes different video over IP transmission methods (i.e.:
RTP over UDP unicast and multicast, as well as RTP over TCP). In addition, it
is furnished with a rich set of offline analysis capabilities. Video-Tester
analysis includes QoS and bitstream parameters estimation (i.e.: bandwidth,
packet inter-arrival time, jitter and loss rate, as well as GOP size and
I-frame loss rate). Our design facilitates the integration of virtually any
existing video quality metric thanks to the adopted Python-based modular
approach. Video-Tester currently provides PSNR, SSIM, ITU-T G.1070 video
quality metric, DIV and PSNR-based MOS estimations. In order to promote its use
and extension, Video-Tester is open and publicly available.Comment: 5 pages, 5 figures. For the Google Code project, see
http://video-tester.googlecode.com
Performance evaluation of an open distributed platform for realistic traffic generation
Network researchers have dedicated a notable part of their efforts
to the area of modeling traffic and to the implementation of efficient traffic
generators. We feel that there is a strong demand for traffic generators
capable to reproduce realistic traffic patterns according to theoretical
models and at the same time with high performance. This work presents an open
distributed platform for traffic generation that we called distributed
internet traffic generator (D-ITG), capable of producing traffic (network,
transport and application layer) at packet level and of accurately replicating
appropriate stochastic processes for both inter departure time (IDT) and
packet size (PS) random variables. We implemented two different versions of
our distributed generator. In the first one, a log server is in charge of
recording the information transmitted by senders and receivers and these
communications are based either on TCP or UDP. In the other one, senders and
receivers make use of the MPI library. In this work a complete performance
comparison among the centralized version and the two distributed versions of
D-ITG is presented
Network traffic analysis and evaluation of a multi-user virtual environment
Virtual world applications allow users to interact within a simulated world. Network responsiveness and reliability contribute to the user experience, thus being able to model and reproduce certain network scenarios is a key issue to assure proper user experience and for being able to provide an estimation of the required network resources. The present study aims to model the client network traffic for the virtual world application Open Wonderland as the basis to tools for evaluating its network requirements. A micro scale modelling was performed, studying the outgoing network traffic from a black box approach that omits the details of traffic generation of the subcomponents and focuses on their overall combined traffic. The model obtained provides high goodness of fit for audio and object synchronisation traffic, reflected in a Pearson correlation coefficient close to its maximum value and low deviation figures measured by Root Mean Square Deviation.Ministerio de Ciencia e innovación IPT-2011-1038-900000Ministerio de Ciencia e innovación TEC2009-10639-C04-0
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