First Person Shooter (FPS) games are a popular online gaming genre played predominately over wired networks. FPS games have stringent delay requirements. However, the explosive growth in wireless LAN (WLAN) deployment has seen an increase in the use of such networks for gaming purposes. The varied performance of the IEEE 802.11 standard has tended to make WLANs unsuitable for FPS games. The IEEE 802.11e enhancement introduces Quality of Service (QoS) mechanisms including Enhanced Distributed Channel Access (EDCA) allowing prioritization of competing flows. Using the NS-2 simulator, we evaluate the capability of 802.11 WLANs to support Quake IV games traffic in the presence of web traffic. We compare the results achieved using EDCA with those achieved by a non-elevated differentiated services scheduler known as Best Effort with Loss Trade-off (BELT). We find that the BELT scheduler compares favorably with EDCA in this context.

Abstract:In this paper, two samples of SU-8, a photo polymer consisting of Gamma-Butyrolactone (GLB) mixed with both Triarylsulfonia and Hexafluroantimonate considered for a Prompt Gamma Activation Analysis (PGAA) diagnostic study. The SU-8 was formed into two organic polymer microturbines which were then given different solidification pretreatment using varying durations of heat baking and Ultra-Violet (UV) crosslinking. In addition to determining the major components of the analyzed samples, some trace elements were also identified, and all the compositions were compared. The measurements were performed at the Budapest Research Reactor (BRR). The obtained results have advanced the industrial applicability of the adopted technique in the considered sector of polymer analysis, because the PGAA has been applied in the case of the polymer of the microturbines. The results obtained are complementary to data achieved by other techniques.

This paper introduces for the first time a numerical example of the data-entropy 'quality-budget' method. The paper builds on an earlier theoretical investigation into the application of this information theory approach for opto-electronic system engineering. Currently the most widely used way of analysing such a system is with the power budget. This established method cannot however integrate noise of different generic types. The traditional power budget approach is not capable of allowing analysis of a system with different noise types and specifically providing a measure of signal quality. The data-entropy budget first introduced by McMillan and Reidel on the other hand is able to handle diverse forms of noise. This is achieved by applying the dimensionless 'bit measure' in a quality-budget to integrate the analysis of all types of losses. This new approach therefore facilitates the assessment of both signal quality and power issues in a unified way. The software implementation of data-entropy has been utilised for testing on a fiber optic network. The results of various new quantitative data-entropy measures on the digital system are given and their utility discussed. A new data mining technique known as data-scatter also introduced by McMillan and Reidel provides a useful visualisation of the relationships between data sets and is discussed. The paper ends by giving some perspective on future work in which the data-entropy technique, providing the objective difference measure on the signals, and datascatter technique, providing qualitative information on the signals, are integrated together for optical communication applications.

Heterogeneous wireless environments are now a reality in many urban areas. Designing and deploying a wireless network in such an environment is complicated by the unpredictable propagation paths of radio signals and by the unpredictable behaviour of the network users themselves. Network simulation and modelling can be used to assist in the design process. However, in order for simulation models to be effective they must be realistic. Efforts have been made to render simulation models more realistic through the analysis of real world wireless networks and through the examination and evaluation of existing simulation models. The most fundamental characteristics of a mobile user are their mobility, and the speed at which they move. The various velocities used in simulation models are unrealistic with respect to pedestrian behaviour in urban environments. In addition, the possible influence of mobile user velocity on the amount of data transferred by the user is not considered. In this paper we examine the influence of a mobile user's velocity on throughput in a wireless network using a range of realistic velocities.

This paper describes a new game assessment metric for the online gamer. The metric is based on a mathematical model currently used for network planning assessment. Beside the traditional network-based parameters such as delay, jitter and packet loss, new parameters based on online players' game experience/knowledge are introduced. The metric aims to estimate game quality as perceived by an online player. Measurements can be achieved in real-time or near real-time and could be useful to both online game players and game service providers. In order to validate and calibrate the proposed metric a subjective game quality assessment is also proposed. Two 5-point scales are introduced: a game-quality scale and a game playing-effort scale. The mean average of each scales termed, as Mean Opinion Score (MOS), will indicate the game quality (MOSGQE) and the playing-effort required (MOSGPE). The results obtained using subjective tests are divided in two parts. The first part is used during the development and calibration of the proposed objective algorithm. The second part is used to validate the proposed algorithm. The algorithm's performance can be measured using Pearson correlation between the subjective and objective MOSGQE scores