26,767 research outputs found

    Clean Power Players: Landing a Job in Clean Energy

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    A new, first-of-its-kind guidebook by Environmental Entrepreneurs (E2) and the Natural Resources Defense Council (NRDC) offers practical, how-to advice for young people seeking careers in clean energy

    A Comprehensive Evaluation Model for Cumputer Based Educaton

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    As opportunities to use computers in learning laboratory settings increase,directors will be faced with the problem of assisting faculty to select and evaluate themost appropriate courseware for their needs. This article presents a comprehensiveevaluation model that could be applied for computer based education programs in avariety of arts and sciences areas. The model includes a pre-implementation stage.This stage determines program compatibility, content evaluation and hardwareconsiderations. A second stage considers formative evaluation, continued availabilityof equipment and the recording of time records. Finally, the last phase, summativeevaluation, includes collecting student attitudes, assessing cost effectiveness,determining external influences and finally, suggesting ways of reaching a decision ofworth. The implementation of this model should provide a system where studentscould work with computer programs of a proven quality. Also, learning laboratorydirectors and faculty could show a certain level of accountability towards spendingmoney on computer software or courseware

    Construction procurement systems : a linkage with project organisational models

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    This paper constitutes a literature review undertaken at the start of a two and a half year EPSRC funded research project. As such, its purpose is to present the details of the ‘re-search’concerning construction procurement and project organizational design. The paper shows that the ‘post -Latham’construction industry provides several new developments (client power, partnering, concurrent engineering etc) which are altering the construction project process, and therefore prove worthy vehicles for investigation into project organizational structures

    Auto-Sizing Neural Networks: With Applications to n-gram Language Models

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    Neural networks have been shown to improve performance across a range of natural-language tasks. However, designing and training them can be complicated. Frequently, researchers resort to repeated experimentation to pick optimal settings. In this paper, we address the issue of choosing the correct number of units in hidden layers. We introduce a method for automatically adjusting network size by pruning out hidden units through ,1\ell_{\infty,1} and 2,1\ell_{2,1} regularization. We apply this method to language modeling and demonstrate its ability to correctly choose the number of hidden units while maintaining perplexity. We also include these models in a machine translation decoder and show that these smaller neural models maintain the significant improvements of their unpruned versions.Comment: EMNLP 201

    Exploring the Impact of Password Dataset Distribution on Guessing

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    Leaks from password datasets are a regular occurrence. An organization may defend a leak with reassurances that just a small subset of passwords were taken. In this paper we show that the leak of a relatively small number of text-based passwords from an organizations' stored dataset can lead to a further large collection of users being compromised. Taking a sample of passwords from a given dataset of passwords we exploit the knowledge we gain of the distribution to guess other samples from the same dataset. We show theoretically and empirically that the distribution of passwords in the sample follows the same distribution as the passwords in the whole dataset. We propose a function that measures the ability of one distribution to estimate another. Leveraging this we show that a sample of passwords leaked from a given dataset, will compromise the remaining passwords in that dataset better than a sample leaked from another source

    A CFD based procedure for airspace integration of small unmanned aircraft within congested areas

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    Future integration of small unmanned aircraft within an urban airspace requires an a posteriori understanding of the building-induced aerodynamics which could negatively impact on vehicle performance. Moving away from generalised building formations, we model the centre of the city of Glasgow using Star-CCMþ, a commercial CFD package. After establishing a critical turbulent kinetic energy for our vehicle, we analyse the CFD results to determine how best to operate a small unmanned aircraft within this environment. As discovered in a previous study, the spatial distribution of turbulence increases with altitude. It was recommended then that UAVs operate at the minimal allowable altitude within a congested area. As the flow characteristics in an environment are similar, regardless of inlet velocity, we can determine areas within a city which will have consistently low or high values of turbulent kinetic energy. As the distribution of turbulence is dependent on prevailing wind directions, some directions are more favourable than others, even if the wind speed is unchanging. Moving forward we should aim to gather more information about integrated aircraft and how they respond to turbulence in a congested area

    Network power flow analysis for a high penetration of distributed generation

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    Increasing numbers of very small generators are being connected to electricity distribution systems around the world. Examples include photovoltaics (PV) and gas-fired domestic-scale combined heat and power (micro-CHP) systems, with electrical outputs in the region of 1 to 2 kW. These generators are normally installed within consumers' premises and connected to the domestic electricity supply network (230 V single-phase in Europe, 120 V in North America). There is a growing need to understand and quantify the technical impact that high penetrations of such generators may have on the operation of distribution systems. This paper presents an approach to analyzing this impact together with results indicating that considerable penetrations of micro-generation can be accommodated in a typical distribution system
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