SATNAC 2008 Conference Papers
Innovation & Regulatory
Title: A Surface Acoustic
Wave Touchscreen-Type Device Using Two Transducers
Authors: Mehrdad
Ghaziasgar (University of the
Abstract: Current
wireless human-computer interaction devices such as wireless mice and
touchscreens, by-and-large, incorporate a sophisticated electronic
architecture. The sophistication achieves wireless capabilities but carries
over a cost overhead. In this paper we investigate the feasibility of
developing a novel human-computer interaction
device with reduced hardware sophistication. We developed a surface
acoustic wave touchscreen-type device using only two transducers, as opposed
to, typically, three or more transducers in conventional surface acoustic wave
touchscreens. The transducers are mounted on a glass surface and connected into
the line-in of a stereo sound card.
User-initiated taps are detected, analysed and located on the surface, and the
mouse cursor is moved to the correct screen location.
Title: Adapting x264 to
Aysynchronous Video Telephony for the Deaf
Authors: Zhenyu
Ma (University of the
Abstract: Deaf
people want to communicate remotely with sign language. Sign language requires
sufficient video quality to be intelligible. Internet-based real-time video
tools do not provide that quality. Our approach is to use asynchronous
transmission to maintain video quality. Unfortunately, this entails a
corresponding increase in latency. To reduce latency as much as possible, we
sought to adapt a synchronous video codec to an asynchronous video application.
First we compared several video codecs with subjective and objective metrics.
This paper describes the process by which we chose x264 and integrated it into
a Deaf telephony video application, and experimented to configure x264
optimally for the asynchronous environment.
Title: Evaluation of the
IMS-based MSF architecture against network architectural requirements
Authors: Prathaban
Moodley (University of the Witwatersrand), Hu Hanrahan (University of the
Abstract: Telcos
are working toward an infrastructure that has a QoS enabled transport network;
a softswitch type architecture for call or session control; and an
infrastructure that enables applications to be generated and provisioned by a
variety of providers. There have been many proposals such as TINA, TIPHON,
H.323, SIP, etc. that address parts of the problem. The current incarnations of
IMS is the choice for call and session signalling for example IMS within the
MSF architecture. The ideal network architectural requirements have been
defined to address the telco requirements. The MSF’s IMS based
architecture is evaluated against the generic architectural requirements by
reviewing the characteristics of the architecture by analysis of the control
messages for an assortment of call setup scenarios. A Message Sequence Chart is
presented for the call setup scenario. The MSF architecture is found to be
incomprehensive in providing for the future mutliservice network requirements.
Title: A Dynamic Packet
Aggregation Scheme for VoIP in Wireless Mesh Networks
Authors: James Okech (
Abstract: Wireless
mesh networks (WMNs) based on IEEE 802.11 standard is a new trend in networking
combining performance, simplicity and economics suitable for backhaul
deployments. However, service providers and carriers understand the cost of
making large scale adoption of infant technologies. If WMNs are to compete with
existing broadband networks, then the technology must evolve from low cost
consumer deployment to carrier-grade structures with improved performance and
robustness. WMNs have brought unique challenges because its broader coverage
calls for accommodation of increased number of clients with varied service
demands. For WMNs backhaul with voice over Internet protocol (VoIP) clients,
the stringent quality of service (QoS) requirements present additional
challenge. This paper proposes a dynamic packet aggregation algorithm that
adjusts the size of aggregation packet to improve VoIP QoS in WMNs. Simulation
results show that the proposed algorithm reduces end-to-end delay, jitter and
packet loss for VoIP packets in WMNs.
Title: End-to-End Quality of
Service Scheme for WLAN-Wired Networks
Authors: Samuel
Senkindu (
Abstract: Wireless local area network (WLAN)
can be used to complement existing last-mile access networks such as ADSL and WiMAX, in the provision of telecommunication services.
However, because of the use of IP, it is difficult to provide service
guarantees to multimedia traffic such as voice and video. This paper seeks to
address the challenge of the provision of quality of service (QoS) to WLAN access network users connected to a
telecommunication service network over a wired backbone link. The focus of the
paper is the interworking of the WLAN EDCA QoS scheme and the IP layer QoS
scheme on the wired network in order to ensure that service guarantees are
provided to multimedia traffic. The QoS interworking consists of mapping EDCA access categories
(AC) to IP traffic classes in the wired network. The mapping function ensures
the consistent application of QoS to the traffic
classes on both the wireless and wired networks. The proposed scheme is
evaluated and found to perform better than a WLAN-wired network without a QoS integration scheme.