Karl Friedrich Siburg  Pavel A. Stoimenov 《统计学通讯:理论与方法》2013,42(19):3124-3134

We present a new way of constructing n-copulas, by scaling and gluing finitely many n-copulas. Gluing for bivariate copulas produces a copula that coincides with the independence copula on some grid of horizontal and vertical sections. Examples illustrate how gluing can be applied to build complicated copulas from simple ones. Finally, we investigate the analytical as well as statistical properties of the copulas obtained by gluing, in particular, the behavior of Spearman's ρ and Kendall's τ.  相似文献   

    

Karl Inderfurth  Rainer Kleber 《Production and Operations Management》2013,22(1):54-70

After‐sales service is a major source of profit for many original equipment manufacturers in industries with durable products. Successful engagement in after‐sales service improves customer loyalty and allows for competitive differentiation through superior service like an extended service period during which customers are guaranteed to be provided with service parts. Inventory management during this period is challenging due to the substantial uncertainty concerning demand over a long time horizon. The traditional mechanism of spare parts acquisition is to place a large final order at the end of regular production of the parent product, causing major holding costs and a high level of obsolescence risk. With an increasing length of the service period, more flexibility is needed and can be provided by adding options like extra production and remanufacturing. However, coordinating all three options yields a complicated stochastic dynamic decision problem. For that problem type, we show that a quite simple decision rule with order‐up‐to levels for extra production and remanufacturing is very effective. We propose a heuristic procedure for parameter determination which accounts for the main stochastic and dynamic interactions in decision making, but still consists of relatively simple calculations that can be applied to practical problem sizes. A numerical study reveals that the heuristic performs extremely well under a wide range of conditions, and therefore can be strongly recommended as a decision support tool for the multi‐option spare parts procurement problem. A comparison with decision rules adapted from practice demonstrates that our approach offers an opportunity for major cost reductions.  相似文献   

    

George E. Nakos  Yannis A. Hajidimitriou 《Global Business and Organizational Excellence》2009,28(5):70-83

Greece has emerged in recent years as an attractive business destination for international companies. European Union membership and the adoption of the euro have greatly changed the Greek economy. This article outlines recent changes in the Greek political and economic environment and the opportunities and challenges that international managers face in Greece. Energy, technology, tourism, and food and beverage industries are the hot sectors of the economy where foreign investors are expected to concentrate their interest in the future. © 2009 Wiley Periodicals, Inc.  相似文献   

    

Bogdan C. Bichescu  Michael J. Fry  George G. Polak 《Production and Operations Management》2009,18(1):33-47

We model a situation where a firm wishes to balance workload requirements by creating a portfolio of recurrent insourcing and outsourcing contracts. We use harmonic analysis to decompose an input workload profile into a portfolio of insourcing and outsourcing contracts using rectangular‐wave basis functions to better achieve some desired constant workload level. However, this initial selection of contracts may result in impractical options. Therefore, we also develop mathematical programs using principles from goal programming and integer programming to refine the portfolio of contracts to more accurately reflect a realistic environment by placing constraints on the available contracts and explicitly considering operational costs. We consider several modeling extensions including the ability to hold limited amounts of inventory and the use of one‐shot contracts to supplement our portfolio of recurrent contracts.  相似文献   

    

George Li  Sampath Rajagopalan 《Production and Operations Management》2008,17(1):61-74

We use a real‐options approach to analyze investments in process improvement. We develop a simple, stochastic model of a firm making investment decisions in process improvement. Our analysis offers several interesting insights into investments in process improvement. First, early investment in process improvement results in valuable knowledge, which helps increase the value of the option to invest in process improvement in future periods. This may motivate a firm to invest in process improvements as early as possible. Second, it may be optimal for a firm to stop investing when such investments do not create enough value in the later stages of the investment horizon. Third, although one would expect the state of a firm's process relative to that of other firms to impact a firm's decision to invest in process improvement, this study finds that the impetus is conditional and identifies these conditions. Finally, in such an environment, the delay of investment in process improvement incurs an opportunity cost for a firm, and we show that the traditional net present value rule must incorporate this opportunity cost and the knowledge‐induced change in future option values to lead to a correct investment decision.  相似文献   

    

Abdurrahman Aydemir  George J. Borjas 《Journal of the European Economic Association》2007,5(4):663-708

Using data drawn from the Canadian, Mexican, and U.S. censuses, we find a numerically comparable and statistically significant inverse relation between immigrant‐induced shifts in labor supply and wages in each of the three countries: A 10% labor supply shift is associated with a 3%–4% opposite‐signed change in wages. Despite the similarity in the wage response, the impact of migration on the wage structure differs significantly across countries. International migration narrowed wage inequality in Canada; increased it in the United States; and reduced the relative wage of workers at the bottom of the skill distribution in Mexico. (JEL: J31, J61)  相似文献   

    

Karl Taylor 《LABOUR》2006,20(1):91-124

Abstract. This paper looks at male wage inequality in the UK across industries and regions over a 15 year period. After controlling for the heterogeneity of productivity characteristics across the population, that part of wage inequality which cannot be explained by observable worker characteristics is examined. This is undertaken at both the industry and regional level to assess the key themes dominant in the literature capable of explaining within‐group wage inequality, namely: technology; globalization; female participation; immigration; shifts in the supply of relative education across cohorts; and falling unionization.  相似文献   

    

Karl Fischer  Steven E. Gross  Helen M. Friedman 《Global Business and Organizational Excellence》2003,22(2):19-24

Using a massive, five‐year database of its own employment history, Marriott found that the cost of certain rewards was offset by lower turnover. And so it took a comprehensive look at its entire rewards program to align compensation and benefits with its associates' needs; improve attraction and retention; enhance productivity; and increase its return on the billions of dollars it invests annually in people. It did this while demonstrating the bottom‐line impact of the resultant strategy. © 2003 Wiley Periodicals, Inc.  相似文献   

  总被引：3，自引：0，他引：3  

George Gaskell  Nick Allum  Wolfgang Wagner  Nicole Kronberger  Helge Torgersen  Juergen Hampel  Julie Bardes 《Risk analysis》2004,24(1):185-194

Public opposition to genetically modified (GM) food and crops is widely interpreted as the result of the public's misperception of the risks. With scientific assessment pointing to no unique risks from GM crops and foods, a strategy of accurate risk communication from trusted sources has been advocated. This is based on the assumption that the benefits of GM crops and foods are self-evident. Informed by the interpretation of some qualitative interviews with lay people, we use data from the Eurobarometer survey on biotechnology to explore the hypothesis that it is not so much the perception of risks as the absence of benefits that is the basis of the widespread rejection of GM foods and crops by the European public. Some respondents perceive both risks and benefits, and may be trading off these attributes along the lines of a rational choice model. However, for others, one attribute-benefit-appears to dominate their judgments: the lexicographic heuristic. For these respondents, their perception of risk is of limited importance in the formation of attitudes toward GM food and crops. The implication is that the absence of perceived benefits from GM foods and crops calls into question the relevance of risk communication strategies for bringing about change in public opinion.  相似文献   

    

George  Ian 《European Management Journal》2004,22(6):624-636

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