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Linear programming and other operations research techniques have been used to assist school administrators and planners in assigning students to schools to achieve racial balances. A linear programming approach to the school busing problem is analyzed in some detail. Six different linear programming models allow examination of the effects of changes in the parameters of the models upon assignment of students. Various ways in which school officials may use the solutions to the models and the postoptimality analysis of the models for educational planning are discussed.  相似文献   
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Motivated by research in psychology and experimental economics, we assume that investors update their beliefs about an asset's value upon observing the price, but only when the price clearly reveals that others obtained private information that differs from their own private information. Specifically, we assume that investors learn from the price of an asset in an asymmetric manner—they learn from the price if they observe good (bad) private information and the price is worse (better) than what is justified based on public information alone. We show that asymmetric learning from an asset's price leads to post‐earnings‐announcement drift (PEAD), and that it generates arbitrage opportunities that are less attractive than alternative explanations of PEAD. In addition, our model predicts that PEAD will be concentrated in earnings surprises that are not dominated by accruals, and it also predicts that earnings response coefficients will decline in the magnitude of the earnings surprises.  相似文献   
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This article examines the financial security issues raised by the rapid development of high-frequency trading (HFT). HFT involves automated algorithmic trading of financial instruments where the objective is to reduce the time scale between the initiation and execution of trades to microseconds (or even nanoseconds) so as to reap competitive advantage. After outlining the contours of a HFT world, the presentation goes on to discuss some of its important consequences and implications. Several matters are discussed in this context: market manipulation, hacking, index construction and violence. Of particular significance for the notion of financial security is the issue of time as embodied in algorithmic trading. In turn this raises concerns over the regulation and management of this new field of financial innovation and trading activity.  相似文献   
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With the growth of virtual organisations and multinational companies, virtual collaboration tasks are becoming more important for employees. This paper describes the development of a virtual meeting system called V-ROOM. An exploration of facilities required in such a system has been conducted. The findings highlighted that intelligent systems are needed, especially since information that individuals have to know and process is vast. The survey results showed that meeting summarisation is one of the most important new features that should be added to virtual meeting systems for enterprises. This paper highlights the innovative methods employed in V-ROOM to produce relevant meeting summaries. V-ROOM’s approach is compared to other methods from the literature, and it is shown how the use of metadata provided by parts of the V-ROOM system can improve the quality of summaries produced.  相似文献   
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Broadband telecommunication service is growing rapidly and its economic impact is likely to vary considerably around the globe. Considerable interest is being shown in wireless broadband, especially in low income and rural areas. This study focuses on the direct effect (broadband penetration as an input), and separately, the productive efficiency effect of broadband (as an information network externality), using a model developed in Thompson and Garbacz (2007). Aggregate fixed and mobile broadband usage and their effect are analyzed and compared first on a sample of forty-three countries with sufficient data. The same models are used on samples of high income and low income countries. It is hypothesized that the rapid growth of broadband could have a stronger effect for low income countries and their initial levels of network development. Key variables are adjusted to a per household basis, using information on household size. Due to the endogeneity of key variables, instrumental variables are employed to estimate separate equations for mobile broadband and fixed broadband. Predicted values for these variables are used in the final equations in order to adjust for endogeneity and omitted variable bias. The results of the model estimated for the full sample indicate that mobile broadband has an important direct effect on GDP, but fixed broadband has an effect no different than zero. In the models with high and low income samples it is apparent that low income countries derive significantly more benefit from mobile broadband. Estimates from the Stochastic Frontier Model find mobile broadband to be a significant driver of growth via a reduction of inefficiency.  相似文献   
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