A Game-Theoretic Approach to Energy-Efficient Modulation in CDMA Networks with Delay QoS Constraints

A game-theoretic framework is used to study the effect of constellation size on the energy efficiency of wireless networks for M-QAM modulation. A non-cooperative game is proposed in which each user seeks to choose its transmit power (and possibly transmit symbol rate) as well as the constellation size in order to maximize its own utility while satisfying its delay quality-of-service (QoS) constraint. The utility function used here measures the number of reliable bits transmitted per joule of energy consumed, and is particularly suitable for energy-constrained networks. The best-response strategies and Nash equilibrium solution for the proposed game are derived. It is shown that in order to maximize its utility (in bits per joule), a user must choose the lowest constellation size that can accommodate the user's delay constraint. This strategy is different from one that would maximize spectral efficiency. Using this framework, the tradeoffs among energy efficiency, delay, throughput and constellation size are also studied and quantified. In addition, the effect of trellis-coded modulation on energy efficiency is discussed.Comment: To appear in the IEEE Journal on Selected Areas in Communications (JSAC): Special Issue on Non-Cooperative Behavior in Networking, August 200

A Game-Theoretic Approach to Energy-Efficient Modulation in CDMA Networks with Delay Constraints

A game-theoretic framework is used to study the effect of constellation size on the energy efficiency of wireless networks for M-QAM modulation. A non-cooperative game is proposed in which each user seeks to choose its transmit power (and possibly transmit symbol rate) as well as the constellation size in order to maximize its own utility while satisfying its delay quality-of-service (QoS) constraint. The utility function used here measures the number of reliable bits transmitted per joule of energy consumed, and is particularly suitable for energy-constrained networks. The best-response strategies and Nash equilibrium solution for the proposed game are derived. It is shown that in order to maximize its utility (in bits per joule), a user must choose the lowest constellation size that can accommodate the user's delay constraint. Using this framework, the tradeoffs among energy efficiency, delay, throughput and constellation size are also studied and quantified. The effect of trellis-coded modulation on energy efficiency is also discussed.Comment: Appeared in the Proceedings of the 2007 IEEE Radio and Wireless Symposium, Long Beach, CA, January 9-11, 200

Experimental investigation on consolidation behavior of mud: Subreport 1. Methodology study

Due to the complex nature of mud consolidation within harbours, a robust and accurate guideline to evaluate the nautical depth is still under debate. Besides, alternative dredging techniques (e.g. mud conditioning/fluidising) have proven to be an applicable method to reduce dredging costs in a number of harbours. Yet, before one can define new criteria for nautical depth or implement new dredging techniques, a deeper understanding of the temporal evolution of rheological, mechanical and biological characteristics of mud is needed. In this study, we aim to improve the understanding of the rheological properties of consolidating mud by comparing the consolidation process of mud from 5 different locations namely the harbours of Zeebrugge (ZB) and Deurganckdok (DG) in Belgium, the harbours of Rotterdam (RO) and Ijmuiden (IJ) in the Netherlands and the Emden (EM) harbour in Germany. The main objectives of this project are to examine the effect of the consolidation process on the mechanical, rheological and biological characteristics of mud as well as to explain the differences in consolidation processes between muds from different origins.This sub-report describes the properties of different mud types used for the experiments as well as the experimental setup. The experimental setup includes a detailed description of the governing parameters, experimental design and measurement techniques conducted on two different consolidation columns, small and large

Workflows and individual differences during visually guided routine tasks in a road traffic management control room

Road traffic control rooms rely on human operators to monitor and interact with information presented on multiple displays. Past studies have found inconsistent use of available visual information sources in such settings across different domains. In this study, we aimed to broaden the understanding of observer behaviour in control rooms by analysing a case study in road traffic control. We conducted a field study in a live road traffic control room where five operators responded to incidents while wearing a mobile eye tracker. Using qualitative and quantitative approaches, we investigated the operators’ workflow using ergonomics methods and quantified visual information sampling. We found that individuals showed differing preferences for viewing modalities and weighting of task components, with a strong coupling between eye and head movement. For the quantitative analysis of the eye tracking data, we propose a number of metrics which may prove useful to compare visual sampling behaviour across domains in future

A Comparison of Displays and Associated Workload on Nuclear Power Plants Tasks

Nuclear Power Plant (NPP) operators complete a variety of tasks to ensure the NPP is running safely and efficiently. However, the levels and types of workload associated with the different task types are not yet fully understood. The present investigation examined workload levels and types for three common NPP Main Control Room (MCR) tasks in a controlled experimental environment using a variety of subjective and performance measures of workload. The results suggest that the three task types differ in the levels and types of workload. These findings can be used to better understand the types of NPP tasks that induce workload and the type of workload they induce. The full results of these experiments will be captured in future articles and technical reports