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51.
Numerous studies document that criminal activity is positively related to unemployment and negatively related to educational attainment levels within given communities. We study this phenomenon in the context of a search‐equilibrium model, in which agents choose between formal employment and pursuing crime‐related activities (theft). Prior to their “occupational choices,” agents undertake costly schooling, raising their productivity. Crime acts, in essence, as a tax on human capital by affecting the probability that a worker's earnings (possessions) are subsequently appropriated. There are multiple equilibria. High crime, low levels of educational attainment, long spells of unemployment, and poverty are correlated across them.  相似文献   
52.
While the benefits of being market oriented are largely accepted, a group of scholars and managers remain skeptical. Marketing scholars have sought to counter the criticisms leveled against market orientation (MO) by arguing that it has both responsive and proactive dimensions. However, few studies have empirically examined the complexity of the effects of these dimensions on firm performance. Drawing on theories of resource‐based advantage and organizational search behavior, this article advances understanding by arguing that responsive and proactive market orientations have curvilinear effects on product development performance, that their interaction may be positively related to product development performance, and that their effects on new product program performance are moderated differentially by the organizational implementation conditions and marketing function power. Survey results of 175 U.S. firms indicate support for most of the hypotheses. Specifically, whereas responsive MO has a U‐shaped relationship with new product program performance, proactive MO has an inverted U‐shaped relationship with new product program performance. Contrary to the arguments presented here, the interaction of both orientations is negatively related to new product program performance. This study finds that both orientations are needed; however, new product program performance is enhanced when one is at higher level and the other is at lower level. Finally, responsive MO is only positively related to new product program performance under specific conditions such as when strategic consensus among managers is high. On the other hand, the positive effect of proactive MO on new product program performance is further strengthened when learning orientation and marketing power are high. Overall, this study suggests that the effects of responsive and proactive MO on new product program performance are more complex than previously theoretically argued and empirically examined.  相似文献   
53.
We propose two novel approaches for feature selection and ranking tasks based on simulated annealing (SA) and Walsh analysis, which use a support vector machine as an underlying classifier. These approaches are inspired by one of the key problems in the insurance sector: predicting the insolvency of a non‐life insurance company. This prediction is based on accounting ratios, which measure the health of the companies. The approaches proposed provide a set of ratios (the SA approach) and a ranking of the ratios (the Walsh analysis ranking) that would allow a decision about the financial state of each company studied. The proposed feature selection methods are applied to the prediction the insolvency of several Spanish non‐life insurance companies, yielding state‐of‐the‐art results in the tests performed. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
54.
A feature transformation method based on domain knowledge for arti?cial neural networks (ANNs) is proposed. The method of feature transformation based on domain knowledge converts continuous values into discrete values in accordance with the knowledge of experts in speci?c application domains. This approach effectively ?lters data, trains the classi?er, and extracts the rules from the classi?er. In addition, it reduces the dimensionality of the feature space, which not only decreases the cost and time in the operation but also enhances the generalizability of the classi?er. The experimental results of the proposed approach will be compared and tested statistically with the results of the linear transformation method. The results show that the method of feature transformation based on domain knowledge outperforms the linear transformation in modelling of ANNs. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
55.
The Cuban economy has experienced a significant increase in foreign direct investment over the past decade due to the end of the Soviet Union and the establishment of more liberal trade policies. Although the U.S. embargo of trade with Cuba still exists, there has been movement lately that suggests the end of the four‐decades‐old policy. The purpose of this article is to analyze the current Cuban business environment and to identify potential entrepreneurial opportunities in the service sector. Major trade partners are also reviewed and managerial implications discussed. © 2006 Wiley Periodicals, Inc.  相似文献   
56.
ABAPO 2.1 (Assets/Business(es) Analyser and Portfolio Optimizer) is a DSS prototype for portfolio managers. It assists the decision maker in two important stages of his task. First, it provides an integrated synthesis of the returns scenario in order to support the decision maker in the selection of the assets to retain, in accordance with his strategy. Second, on the retained assets it computes and shows the E- efficient solutions. For each efficient portfolio ABAPO supplies immediately a lot of information that should help the decision maker to single out the portfolio which fits his goals best.ABAPO works on an integration of elements derived from the Portfolio Selection Theory, the Capital Asset Pricing Model, the Utility Theory. ABAPO uses the principal component, the univariate, the bivariate regression and the correlation analysis, a parametric quadratic programming model and an algorithm based on the critical line method.ABAPO is implemented in C language under AIX operating system and runs on a IBM RT PC 6150. It is a ductile, interactive procedure that involves graphics in order to increase the efficiency and the effectiveness of the what if simulations.This version 2.1 improves upon the previous one by the evaluation of the Security Market Line, some statistics on the returns of the efficient portfolios, the evaluation of the quadratic indifference curves associated to the efficient portfolios.Research supported by the Italian National Research Council (CNR), grant n. 88.03065.10. ABAPO DSS 2.1 prototype has been developed with the support of the CNR (grant n. 87.1210.10), of the Banca Popolare di Verona, of the Cassa di Risparmio di Verona Vicenza e Belluno, of the Società Cattolica di Assicurazione, at the Istituto di Matematica, Università di Verona.  相似文献   
57.
It is known that discretionary policy may give rise to an inflationary bias if wages are negotiated in nominal terms. In a recent issue of this Review, Guzzo and Velasco argued that this bias can be eliminated, and welfare maximized, by the appointment of a central banker who does not care at all about inflation (a ‘populist’ central banker). A conceptual flaw of the latter result is identified here. It is shown that when wages are negotiated in nominal terms the result is true only in the special case of a single, all-encompassing, union. In the more general case of multiple unions, however, inflation increases linearly with their number and a populist central bank may turn out to decrease welfare.  相似文献   
58.
We estimate the respective contributions of institutions, geography, and trade in determining income levels around the world, using recently developed instrumental variables for institutions and trade. Our results indicate that the quality of institutions trumps everything else. Once institutions are controlled for, conventional measures of geography have at best weak direct effects on incomes, although they have a strong indirect effect by influencing the quality of institutions. Similarly, once institutions are controlled for, trade is almost always insignificant, and often enters the income equation with the wrong (i.e., negative) sign. We relate our results to recent literature, and where differences exist, trace their origins to choices on samples, specification, and instrumentation.  相似文献   
59.
We propose an optimal filter to transform the Conference Board Composite Leading Index (CLI) into recession probabilities in the US economy. We also analyse the CLI's accuracy at anticipating US output growth. We compare the predictive performance of linear, VAR extensions of smooth transition regression and switching regimes, probit, non‐parametric models and conclude that a combination of the switching regimes and non‐parametric forecasts is the best strategy at predicting both the NBER business cycle schedule and GDP growth. This confirms the usefulness of CLI, even in a real‐time analysis. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
60.
Stochastic stability in networks with decay   总被引:1,自引:0,他引:1  
This paper considers a stylized model of network formation in which relations among agents are subject to frictions, as described in Bala and Goyal [A non cooperative model of network formation, Econometrica 68 (2000) 1181-1231]. We analyze the process of network formation in a dynamic framework where self-interested individuals can form or delete links and, occasionally, make mistakes. Then, using stochastic stability, we identify the network structures to which the formation process will converge.  相似文献   
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