BACKGROUND Between September 17 and October 3, 2009, hundreds of workers employed in a manufacturing factory in Shenzhen, a city in south China developed a sudden onset of acute gastroenteritis. A retrospective cohort study is designed to identify the risk factors and control this outbreak. METHODS Information on demographic characteristics, working place, the history of contact with a person...

In this paper, it was firstly confirmed by FEM analysis of ground during earthquake that two kinds of techniques using both displacements of hollow and natural grounds in seismic deformation method were equivalent. Then, the authors were proposed a criterion for evaluating applicability of seismic deformation method, based on comparison of calculated results of both the above-mentioned techniqu...

The projected increases in World population and need for food have recently motivated adoption of information technology solutions in crop fields within precision agriculture approaches. Internet of underground things (IOUT), which consists of sensors and communication devices, partly or completely buried underground for real-time soil sensing and monitoring, emerge from this need. This new par...

In underground mines and tunnels accurate and continuous positioning of moving machines and humans has been studied extensively. Geomagnetic field based positioning is an interesting possibility for this measurement need. Using a commercial smart phone and a new calculation service provided by a Finnish company, a feasibility and accuracy assertion tests were done in Finnish underground mine. F...

Wireless Underground Sensor Networks (WUSNs) are the networks of wireless sensors that operate in the underground soil medium. In this monograph, to realize reliable and efficient WUSNs, two enabling techniques are developed to address the challenges brought by the underground soil medium, including the EM wave-based WUSNs and the MI-based WUSNs. For EM wave-based WUSNs, the heterogeneous netwo...

A low cost, battery-operated, portable, real-time aerosol analyzer is not available for monitoring diesel particulate matter (DPM) concentrations in underground mines. This study summarizes a field evaluation conducted at an underground limestone mine to evaluate the potential of the TSI AM 510 portable photometer (equipped with a Dorr-Oliver cyclone and 1.0-mum impactor) to qualitatively track...