7,503 research outputs found

    Panel on future challenges in modeling methodology

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    This panel paper presents the views of six researchers and practitioners of simulation modeling. Collectively we attempt to address a range of key future challenges to modeling methodology. It is hoped that the views of this paper, and the presentations made by the panelists at the 2004 Winter Simulation Conference will raise awareness and stimulate further discussion on the future of modeling methodology in areas such as modeling problems in business applications, human factors and geographically dispersed networks; rapid model development and maintenance; legacy modeling approaches; markup languages; virtual interactive process design and simulation; standards; and Grid computing

    The Evolution of Transport Networks

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    Between 1900 and 2000, the length of paved roads in the United States increased from 240 km to 6,400,000 km (Peat 2002, BTS 2002) with virtually 100% of the U.S. population having almost immediate access to paved roadways. Similarly, in 1830 there were 37 km of railroad in the United States, but by 1920 total track mileage had increased more than ten-thousand times to 416,000 km miles, however since then, rail track mileage has shrunk to about 272,000 km (Garrison 1996, BTS 2002). The growth (and decline) of transport networks obviously affects the social and economic activities that a region can support; yet the dynamics of how such growth occurs is one of the least understood areas in transport, geography, and regional science. This is revealed time and again in the long-range planning efforts of metropolitan planning organizations (MPOs), where transport network changes are treated exclusively as the result of top-down decision-making. Changes to the transport network are rather the result of numerous small decisions (and some large ones) by property owners, firms, developers, towns, cities, counties, state department of transport districts, MPOs, and states in response to market conditions and policy initiatives. Understanding how markets and policies translate into facilities on the ground is essential for scientific understanding and improving forecasting, planning, policy-making, and evaluation.Transportation Network Growth, Transportation-Land Use Interaction, Markov Chain

    Commercial-off-the-shelf simulation package interoperability: Issues and futures

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    Commercial-Off-The-Shelf Simulation Packages (CSPs) are widely used in industry to simulate discrete-event models. Interoperability of CSPs requires the use of distributed simulation techniques. Literature presents us with many examples of achieving CSP interoperability using bespoke solutions. However, for the wider adoption of CSP-based distributed simulation it is essential that, first and foremost, a standard for CSP interoperability be created, and secondly, these standards are adhered to by the CSP vendors. This advanced tutorial is on an emerging standard relating to CSP interoperability. It gives an overview of this standard and presents case studies that implement some of the proposed standards. Furthermore, interoperability is discussed in relation to large and complex models developed using CSPs that require large amount of computing resources. It is hoped that this tutorial will inform the simulation community of the issues associated with CSP interoperability, the importance of these standards and its future

    COVID 19 Impact on Aircraft Ground Time at Congonhas Airport (CGH)

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    This project aims to research and analyze the impact of the increase of ground time at Congonhas Airport caused by the new safety procedures in aviation to avoid the spread of the COVID-19 virus. Aviation is a highly regulated industry, with the high cost and tiny margins. It focuses on optimizing one of the most expensive assets, the aircraft. To keep aircraft flying is one of the airline\u27s primary goals as aircraft on the ground means no revenue generation and cost increase. Congonhas Airport is one of the busiest airports in Brazil and already operated on its limited capacity before the crisis; higher ground time will bring operational and financial impact to the airlines, airport administrators, and suppliers. We selected the public database from ANAC and ABEAR that contains detailed data about arrivals and departures at Congonhas Airport to analyze the impact. We also used v available data from INFRAERO about the capacity and operational restrictions of the airport. In the first phase of the analysis, we worked with Python to measure the ground time duration before and after implementing the new procedures and validating the ground time increase hypothesis. The second phase was performed using Arena Software to simulate the airport\u27s movements, considering airlines\u27 ground time before and after implementing the new procedures. The results from both analyzes were complementary and allowed to confirm the hypothesis and identify the impact of the increase in the ground time due to the new cleaning and social distancing measures adopted during the COVID-19 pandemic

    64-bit architechtures and compute clusters for high performance simulations

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    Simulation of large complex systems remains one of the most demanding of high performance computer systems both in terms of raw compute performance and efficient memory management. Recent availability of 64-bit architectures has opened up the possibilities of commodity computers accessing more than the 4 Gigabyte memory limit previously enforced by 32-bit addressing. We report on some performance measurements we have made on two 64-bit architectures and their consequences for some high performance simulations. We discuss performance of our codes for simulations of artificial life models; computational physics models of point particles on lattices; and with interacting clusters of particles. We have summarised pertinent features of these codes into benchmark kernels which we discuss in the context of wellknown benchmark kernels of the 32-bit era. We report on how these these findings were useful in the context of designing 64-bit compute clusters for high-performance simulations

    E-finance-lab at the House of Finance : about us

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    The financial services industry is believed to be on the verge of a dramatic [r]evolution. A substantial redesign of its value chains aimed at reducing costs, providing more efficient and flexible services and enabling new products and revenue streams is imminent. But there seems to be no clear migration path nor goal which can cast light on the question where the finance industry and its various players will be and should be in a decade from now. The mission of the E-Finance Lab is the development and application of research methodologies in the financial industry that promote and assess how business strategies and structures are shared and supported by strategies and structures of information systems. Important challenges include the design of smart production infrastructures, the development and evaluation of advantageous sourcing strategies and smart selling concepts to enable new revenue streams for financial service providers in the future. Overall, our goal is to contribute methods and views to the realignment of the E-Finance value chain. ..

    “‘Relentless Geography’: Los Angeles’ Imagined Cartographies in Karen Tei Yamashita’s Tropic of Orange,”

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    What would a map of Los Angeles drawn from the ground up look like? In his groundbreaking work The Production of Space (1974), Henri Lefebvre argues that the conceived space of urban planners is fundamentally distinct from lived space, which cannot be mapped out. In her impressive city-wide narrative, Karen Tei Yamashita’s Tropic of Orange (1997) demonstrates the effects of imposing conceived space upon the lived space of inner city Los Angeles residents, and what happens when the counter-model of space being lived by a city’s inhabitants rebels. Yamashita’s text mirrors this disjuncture between represented and lived space through the use of narrative surrealism. Space is magically reconfigured in the city, shrinking the uninhabited Downtown and expanding over-populated yet underrepresented neighborhoods, literally shifting geographically until its mapping matches the social space of those on the ground rather than those who map it from above. Literary criticism on the novel to date has largely interpreted Tropic of Orange as a commentary on the effects of globalization; not enough attention has been paid to the novel’s surreal expansion of Los Angeles’ inner city. Using Lefebvre’s “science of space,” anchored by Los Angeles’ city planning schemas, I argue that Yamashita offers a different map, one perceived by the subsets of LA’s population that fall through the cracks of the city’s grid. Tropic of Orange’s unorthodox formal structure, when combined with its narrative surrealism, creates a differential space in the text, transforming the novel into the Los Angeles imagined by its anonymous users
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