Social and Behavioral Sciences Commons^™

Automatic Reaction To A Chemical Event Detected By A Low-Cost Wireless Chemical Sensing Network, Stephen Beirne, King Tong Lau, Brian Corcoran, Dermot Diamond

Faculty of Science - Papers (Archive)

A test-scale wireless chemical sensor network (WCSN) has been deployed within a controlled Environmental Chamber (EC). The combined signals from the WCSN were used to initiate a controllable response to the detected chemical event. When a particular sensor response pattern was obtained, a purging cycle was initiated. Sensor data were continuously checked against user-defined action limits, to determine if a chemical event had occurred. An acidic contaminant was used to demonstrate the response of the sensor network. Once the acid plume was simultaneously detected by a number of wireless chemical sensor nodes, an automatic response action, which was the purging …

A Food-Based Dietary Strategy Lowers Blood Pressure In A Low Socio-Economic Setting: A Randomised Study In South Africa, Karen E. Charlton, Naomi Levitt, Krisela Steyn, Deborah Jonathan, Nomonde Gwebushe, Nasheeta Peer, Katja Rossouw, Theresa Gogela, Carl J. Lombard

Faculty of Health and Behavioural Sciences - Papers (Archive)

Objective To assess the impact of a food-based intervention on blood pressure (BP) in free-living South African men and women aged 50–75 years, with drug-treated mild-to-moderate hypertension.

Methods A double-blind controlled trial was undertaken in eighty drug-treated mild-to-moderate hypertensive subjects randomised to an intervention (n 40) or control (n 40) arm. The intervention was 8-week provision of six food items with a modified cation content (salt replacement (SOLO™), bread, margarine, stock cubes, soup mix and a flavour enhancer) and 500 ml of maas (fermented milk)/d. The control diet provided the same quantities of the targeted foods but of …

Evaluation Of A Low Cost Wireless Chemical Sensor Network For Environmental Monitoring, Jer Hayes, Stephen Beirne, King-Tong Lau, Dermot Diamond

Faculty of Science - Papers (Archive)

We present work on the development and testing of a low-cost wireless chemical sensor network (WCSN) for monitoring irritant/toxic gases in the environment. The WCSN used in this work takes advantage of recent advances in low power wireless communication platforms and uses colorimetric sensors to detect the presence of certain target gases. This sensor network adopts a star configuration and performs one way RF communications from individual sensor nodes to the base-station. Each node in the network is composed of a multiple sensor platform that measures light intensity, temperature and motion. The light sensor was used as the chemical sensing …

Chemical Event Tracking Using A Low-Cost Wireless Chemical Sensing Network, Stephen T. Beirne, B Corcoran, K T Lau, D Diamond

Faculty of Science - Papers (Archive)

A recently developed low-cost light emitting diode (LED) chemical sensing technique is integrated with a Mica2Dot wireless communications platform to form a deployable wireless chemical event indicator network. The operation of the colorimetric sensing node has been evaluated to determine its reproducibility and limit of detection for an acidic airborne contaminant. A test-scale network of five similar chemical sensing nodes is deployed in a star communication topology at fixed points within a custom built Environmental Sensing Chamber (ESC). Presented data sets collected from the deployed wireless chemical sensor network (WCSN) show that during an acidic event scenario it is possible …

A Low-Complexity Iterative Channel Estimation And Detection Technique For Doubly Selective Channels, Qinghua Guo, Li Ping

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, we propose a low-complexity iterative joint channel estimation, detection and decoding technique for doubly selective channels. The key is a segment-by-segment frequency domain equalization (FDE) strategy under the assumption that channel is approximately static within a short segment. Guard gaps (for cyclic prefixing or zero padding) are not required between adjacent segments, which avoids the power and spectral overheads due to the use of cyclic prefix (CP) in the conventional FDE technique. A low-complexity bi-directional channel estimation algorithm is also developed to exploit correlation information of time-varying channels. Simulation results are provided to demonstrate the efficiency of …

Evolution Analysis Of Low-Cost Iterative Equalization In Coded Linear Systems With Cyclic Prefixes, Xiaojun Yuan, Qinghua Guo, Xiaodong Wang, Li Ping

Faculty of Engineering and Information Sciences - Papers: Part A

This paper is concerned with the low-cost iterative equalization/detection principles for coded linear systems with cyclic prefixes. Turbo frequency-domain-equalization (FDE) is applied to systems that may contain the joint effect of multiple-access interference (MAI), cross-antenna interference (CAI) and inter-symbol interference (ISI). We develop an SNK-variance evolution technique for the performance evaluation of the proposed systems. Numerical results in various channel environments demonstrate excellent agreement between the predicted and simulated system performance. © 2008 IEEE.

Low-Complexity Iterative Detection In Multi-User Mimo Isi Channels, Xiaojun Yuan, Qinghua Guo, Li Ping

Faculty of Engineering and Information Sciences - Papers: Part A

We propose a low-cost detection strategy for multi-user multiple-input-multiple-output (MIMO) systems with inter-symbol interference (ISI). The cyclic prefix (CP) technique is assumed. The proposed detection algorithm is derived in a very concise manner based on some elegant properties of circulant matrices. We show that multi-user detection and equalization can be carried out jointly and efficiently. © 2007 IEEE.