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This article concerns an investigation of the full scale evacuation of a building with a configuration similar to that of the World Trade Center (WTC) north tower using computer simulation. A range of evacuation scenarios is explored in order to better understand the evacuation of the WTC on 11 September 2001. The analysis makes use of response time data derived from a study of published WTC survivor accounts. Geometric details of the building are obtained from architects' plans while the total building population used in the scenarios is based on estimates produced by the National Institute of Standards and Technology formal investigation into the evacuation. This paper attempts to approximate the events of 11 September 2001 and pursue several 'what if' questions concerning the evacuation. In particular, the study explores the likely outcome had a single staircase survived intact from top to bottom. More generally, this paper explores issues associated with the practical limits of building size that can be expected to be efficiently evacuated using stairs alone. [ABSTRACT FROM AUTHOR]

Virtual Reality (VR) can reduce time and costs, and lead to increases in quality, in the development of a product. Given the pressure on car companies to reduce time-to-market and to continually improve quality, the automotive industry has championed the use of VR across a number of applications, including design, manufacturing, and training. This paper describes interviews with 11 engineers and employees of allied disciplines from an automotive manufacturer about their current physical and virtual properties and processes. The results guided a review of research findings and scientific advances from the academic literature, which formed the basis of recommendations for future developments of VR technologies and applications. These include: develop a greater range of virtual contexts; use multi-sensory simulation; address perceived differences between virtual and real cars; improve motion capture capabilities; implement networked 3D technology; and use VR for market research. [ABSTRACT FROM AUTHOR]

The objective of this paper was to study and optimize the concrete paving operations taking place in the reconstruction project of Interstate-74 using computer simulation. To achieve this objective, field data were collected during construction, and were then used to determine adequate probabilistic density functions for the activities’ duration and to test a developed simulation model. Upon testing, the developed model was used to study the impacts of resources on the flow of operations and on the cost effectiveness of the construction process. In general, application of simulation methods to concrete paving operations was successful and its accuracy was acceptable as compared to field measurements. Based on the results of a sensitivity analysis of the critical resources, multiple factors were considered in the decision-making process to ensure that all aspects of the operation are evaluated. This includes total operation time, productivity, costs of the operation, average truck delay, and idle times for the paver and the spreader. For the conditions pertinent to this construction site, ten trucks, one paver and one spreader, and three finishing and plastic-covering crews are recommended. Using this set of resources would result in a prompt and effective execution of the operation. Practical implementation and limitations of the developed model in similar construction operations is discussed. [ABSTRACT FROM AUTHOR]

The article reports on the rise of the weather forecasting machines. The latest from the forecasting wars comes in a paper soon to be published in the "Bulletin of the American Meteorological Society." Meteorologists Jeffrey Baars and Clifford Mass of the University of Washington, Seattle, examined machine-generated forecasts of weather at 29 locations throughout the U.S. during a recent year and compared them with the routine predictions made by forecasters at the National Weather Service (NWS). The machine forecasts begin with model simulations of the coming weather across the U.S. These are generated at NWS's National Centers for Environmental Prediction in Camp Springs, Maryland, from weather observations collected in the preceding few hours. Then, a purely statistical analysis corrects the model forecast, basing its adjustments on comparisons of how well past model forecasts matched reality. That approach, known as Model Output Statistics, can correct any errors the model makes consistently, such as calling for too much warmth or rain or wind.