UWB-based sensor networks for localization in mining environments

Wireless sensor networks (WSN) have attached a great attention in the last few years. WSN offer several advantages over the traditional sensor networks, such as elimination of costly wires, security and larger area coverage. In the last few years, there has been great interest commercial applications based on Ultra Wideband (UWB). It has potentially low complexity, low cost and an excellent time domain resolution which facilitates location and tracking applications. Therefore, UWB provide a good combination of high performance with low complexity for WSN applications. Localization has attracted considerable attention in many fields. Accurate estimation of an individual location can be a difficult task, producing ambiguous results particularly in harsh environment. In this paper, we focus on feasibility study (via simulation and measurements) of using UWB based-WNS as future solution for localization in underground mines.     

Now or later? Striatum and insula activation to immediate versus delayed rewards.

Neuroimaging studies on delay discounting tasks that use reward delays ranging from minutes to days have implicated the insula and striatum in the processing of intertemporal decisions. This study aimed at assessing whether these brain regions would also be involved in decision-making when subjects have to wait through the delays within the range of seconds. Using functional MRI in 13 healthy volunteers, we repeatedly presented monetary options with delays that differed within the range of multiple seconds. Using a region-of-interest approach, we found significant activation in the bilateral anterior insula and striatum when subjects chose either the immediate (smaller) or delayed (larger) option. In particular, insular activation was observed after the response and the delay, when the outcome of the immediate or the delayed choice was shown. Significantly greater activation was observed in the ventroanterior striatum while subjects chose the immediate, as opposed to the delayed, options and also after receiving the outcome of waiting through the longer delay option. The evidence presented here indicates that both the ventral striatum and the insula are involved in the processing of choosing delay options as well as the consequences of choices with delays in the seconds' range. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Actor networks and the construction of applicable knowledge: the case of the Timbre Brownfield Prioritization Tool

This article deals with experiences acquired during the process of developing the Timbre Brownfield Prioritization Tool (TBPT). Developing a decision support tool that takes into account the expectations and experiences of its potential users is similar to creating applicable knowledge by the joint action of scientists and heterogeneous actors. Actor network theory is used to explore the construction of this form of applicable knowledge as a process of actor network creation. Following the French sociologist Callon, networks are seen to be initiated and carried out by a group of scientists (tool developers) via four moments of translation, called problematization, interessement, enrolment and mobilization. Each step in the construction of the TBPT—from the initial research question to the final model—can be linked in retrospect to changing configurations of actor networks. Based on the experiences of the tool developers in the Czech Republic, Poland, Germany and Romania, we illustrate how these configurations varied across space and time. This contribution emphasizes the ability to correlate gains in knowledge with the more visible changes in the scope of actor networks in order to highlight achievements but also limitations in acquiring applicable knowledge.     

The calculation of the heat release rate by oxygen consumption in a controlled‐atmosphere cone calorimeter

The standard cone calorimeter according to ASTM E 1354 and ISO 5660 enables reaction‐to‐fire tests to be performed in ambient atmospheric conditions. A controlled‐atmosphere chamber modifies the standard apparatus in a way that allows tests to be performed in nonambient conditions as well. The enclosed chamber is placed underneath the standard exhaust hood and does not have a closed connection to the hood. With this open arrangement, the exhaust gases are diluted by excess air drawn in from the laboratory surroundings. Heat‐induced changes in the consequential dilution ratio affect the calculation of fire quantities and, when neglected, lead to deviations of up to 30% in heat release rate. The paper introduces a test protocol and equations to calculate the heat release rate taking dilution effects into account. A mathematical correction is shown that compensates for the dilution effects while avoiding extensive mechanical changes in the equipment. Copyright © 2013 John Wiley & Sons, Ltd.