The H.264/AVC video coding standard encapsulates the most advanced video coding tools. Since the various techniques that lead to better coding efficiency of the coding standard also inevitably increase the complexity of the video encoder, real-time H.264 encoding of video streams is a challenging task. If available computational resource does not allow the entire encoding process to be carried out in time, a complexity scalable technique that ensures a graceful degradation of coding performance will be a valuable tool. We designed a video encoding scheme that allows the rate distortion (R-D) process to be carried out in a complexity scalable fashion. Our proposed singularly parameterized complexity scalable scheme allows the control of complexity-coding performance tradeoff when available resources are limited and the optimal R-D performance is unattainable.

We consider the on-demand delivery of layered video over peer-to-peer (P2P) networks. A parallel server architecture enables the service of requests by more than one server, thus reducing load at individual servers and dispersing network load. In a P2P network, peer upload bandwidth is limited and heterogenous, so a P2P streaming session may involve multiple supplying peers of different uplink. Partitioning the video data is a crucial first step in the collaborative delivery of data by multiple servers. If done right, the client's viewing experience can be significantly improved. In this paper, we describe a retrieval strategy that significantly reduces access delay necessary for continous playback when retrieving layers of heterogenous bitrate over multiple connections of heterogenous bandwidth.

We research into using Mobile Sensor Networks to harvest physical quantities that emanate from sources and are distributed in space in hazardous environments. Examples are temperature, toxic emissions and pollutions. Mobile sensors are more advantageous than static sensors in many ways such as easy re-deployment and environmental friendliness. However, they are usually deployed at low node densities with equally spaced nodes. As a result, the reconstructed distribution maps are highly distorted. Our approach attacks the problem from the source, by mobilizing the sensors to harvest data with high information content cooperatively and intelligently. As a result, we achieve 3.6 times in error reduction relative to an equally distributed grid. Moreover, in comparison with the Random Waypoint and Broyden-Fletcher-Goldfarb-Shanno methods, we achieve at least 60% more reduction in energy usage by consuming 70% lesser energy. Finally, our approach has a resource utilization efficiency of 50 times that of static sensors.

In most current implementations of CT2 telepoint systems, only handset initiated calls are allowed. This paper describes a design to allow two-way calling for the CT2 public telepoint system with minimal modifications to the current CT2 infrastructure and the public switched telephone network (PSTN). The design makes use of centralized databases in the home location register (HLR) and visitor location registers (VLR) to track the location of handsets. This location information is stored in the VLR and HLR, and is used by the PSTN to route incoming calls destined for CT2 handsets to the appropriate CT2 telepoint base station (TBS). The TBS connect to the PSTN local exchanges (LE) through the integrated services digital network (ISDN) basic rate interfaces (BRI) for fast out-of-band signaling. We present simulation results of the system with the objective of determining where congestion might occur within the system and to understand the impact of the new implementation on the PSTN. The results indicate that the performance of the system will be limited by the VLR processing speed and the number of ISDN BRI's connecting the ISDN front end (IFE) to the PSTN.>

The paper presents a new MAC protocol, rate-based headend request control (RHRC), for dual unidirectional bus networks, which overcomes the unfairness of DQDB by allowing each station to generate multiple requests while retaining most of the positive features of DQDB, including 100% bandwidth utilization and low access delay at very low load. In addition, the protocol has two attractive features. Firstly, the transmission mechanism controlling station access to the data channel is able to provide approximately equal opportunity to messages so that they experience almost the same average delay independent of their physical locations and the traffic distribution. Secondly, the bandwidth allocation mechanism can achieve fair bandwidth sharing among stations when the network is overloaded, while maintaining fairness in terms of message delay amongst the underloaded stations. This mechanism also results in a shorter transient period than the bandwidth balancing mechanism of DQDB. Simulation results are included and comparisons are made with DQDB.>

The authors study the performance of an adaptive token-passing bus protocol where only active stations participate in the token passing, and therefore make up the logical ring. A station is active over an interval of time if during that interval data are generated at the station to be sent over the network. The size of the logical ring thus varies randomly according to the traffic intensity of the system. Existing analytical results for token-passing systems assume a fixed number of stations, which will take part in the token passing regardless of whether a station is active or not. An approximate analytical model is provided for a token-passing system where the effective size of the ring changes dynamically according to the network traffic.>

Error rates for a narrowband digital FM system with discriminator detection in a land mobile radio channel characterized by fading and Doppler frequency shift are obtained using a new analytical method. The fading rate is assumed to be much slower than the bit rate so that signal distortion through a narrow bandpass filter can be analyzed via a quasistatic approach. An experiment was conducted using a Rayleigh fading simulator, and the error rate measurements are shown to agree well with the calculated results, except at high SNR (signal-to-noise ratio) where an irreducible error rate was observed.>