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101.
Predicting the geo-temporal variations of crime and disorder   总被引:2,自引:0,他引:2  
Traditional police boundaries—precincts, patrol districts, etc.—often fail to reflect the true distribution of criminal activity and thus do little to assist in the optimal allocation of police resources. This paper introduces methods for crime incident forecasting by focusing upon geographical areas of concern that transcend traditional policing boundaries. The computerised procedure utilises a geographical crime incidence-scanning algorithm to identify clusters with relatively high levels of crime (hot spots). These clusters provide sufficient data for training artificial neural networks (ANNs) capable of modelling trends within them. The approach to ANN specification and estimation is enhanced by application of a novel and noteworthy approach, the Gamma test (GT).  相似文献   
102.
This article matches establishment-level data on workplace transformation (e.g., quality circles, work teams, and just-in-time production) with measures of cumulative trauma disorders at these same establishments to explore the relationship between "flexible" workplace practices and workplace health and safety. The results reveal a positive, statistically significant, and quantitatively sizable relationship between cumulative trauma disorders and the use of quality circles and just-in-time production.  相似文献   
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For a compound Poisson process with negative drift and jump distribution consisting of a mixture of exponentials on [0) and on (-, 0), an exact expression is derived for the probability of hitting the level c, c > 0. the problem is motivated by modeling the returns from trading on financial markets.  相似文献   
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The classical warrant pricing formula requires knowledge of the firm value and of the firm‐value process variance. When warrants are outstanding, the firm value itself is a function of the warrant price. Firm value and firm‐value variance are then unobservable variables. I develop an algorithm for pricing warrants using stock prices, an observable variable, and stock return variance. The method also enables estimation of firm‐value variance. A proof of existence of the solution is provided.  相似文献   
108.
Reduced-form price spread models have been recently utilized by Wohlgenant and Mullen, and Thompson and Lyon to evaluate the economic factors affecting the marketing margins for agricultural products. Drawing on Gardner, Heien, Buse and Brandow, Waugh, Tomek and Robinson, and others they specify alternative retail-farm price spread models and attempt to determine which best fit the data in the context of underlying theoretical rationale. This paper continues in the spirit of Wohlgenant and Mullen, and Thompson and Lyon by evaluating alternative specifications of the retail-farm price spread for white maize in South Africa. However, several important differences do remain. Wohlgenant and Mullen analyzed the price spread for beef using annual data, while Thompson and Lyon modeled the price spread for oranges using weekly data. The time period under consideration can be expected to affect the choice of model because fixed markup rules that might be evident using a short-run period of analysis (e.g., Thompson and Lyon) become untenable over the long run with underlying supply and demand shifts. In this paper, monthly data, which may be interpreted as an intermediate-run period, are used along with dichotomous supply-demand shifters. In addition, Brorsen et. al. have shown that price uncertainty affects the price spread in the marketing channels of agricultural commodities. Thus, the analysis in this paper extends the framework of Wohlgenant and Mullen, and Thompson and Lyon to include measures of price risk. Finally, like Brorsen et. al. this study pertains to the grain market, while Wohlgenant and Mullen, and Thompson and Lyon studied the marketing margin for non-storable commodities.  相似文献   
109.
The paper considers how people should plan their saving, given certain assumptions about inheritance and changes in household circumstances. The results are produced by a model that takes into account tax and state benefits as well as various private savings vehicles. It concludes that, for many households, saving for retirement through a ‘pension’ might not be optimum and that the best strategy is to vary the incidence and allocation of saving in response to changes in household circumstances.  相似文献   
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