利用生产停顿机会进行维修以提高产量

介绍Statoil公司提出的机会维修概念和它对生产所起的重要作用,举例说明机会维修的可行性,并对机会维修进行优化使它更好地为生产服务.     

Regime shifts in the Danish term structure of interest rates

Within a bivariate VAR model allowing for two-state Markov regime switching we test and evaluate the Expectations Theory (ET) of the term structure using Danish 1- and 3-months interest rates covering the period 1976–1997. A regime-shift approach is used in order to account for the change in monetary policy and the 1992–93 exchange rate crises that occured during this period. The basic findings are that these episodes did change the term structure, and, although we do find departures from the ET, several of the implications of the theory are consistent with the data, especially in the later part of the sample. First version received: June 1997/Final version received: March 1998     

The Relationship between Slack Resources and the Performance of Entrepreneurial Firms: The Role of Venture Capital and Angel Investors

In this study, we seek to further delineate factors that condition the relationship between slack resources and firm performance. To do so, we develop and test a model that establishes the role of venture capital (VC) and angel investors as powerful external stakeholders who positively moderate the slack–performance relationship. In addition, we provide more insight into this relationship by examining differences between these two types of private investors and by examining the role of their ownership stakes. We test our hypotheses using a sample of 1215 private firms, including VC‐backed firms, angel‐backed firms, and similar firms without such investors. We find that the presence of VC investors positively moderates the relationship between both financial and human slack resources and firm performance, while angel investors only positively moderate the effect of human resource slack. Further, VC investors are only marginally better at helping entrepreneurs to extract value from human resource slack than angel investors and they are no better when it comes to financial slack. Finally, we find that the impact of financial and human resource slack on firm performance is more positive in VC‐backed firms when investors hold high ownership stakes, an effect which is significantly stronger than when angel investors hold high ownership stakes.     

A multivariate Poisson mixture model for marketing applications

This paper describes a multivariate Poisson mixture model for clustering supermarket shoppers based on their purchase frequency in a set of product categories. The multivariate nature of the model accounts for cross-selling effects between the purchases made in different product categories. However, for computational reasons, most multivariate approaches limit the covariance structure by including just one common interaction term, or by not including any covariance at all. Although this reduces the number of parameters significantly, it is often too simplistic as typically multiple interactions exist on different levels. This paper proposes a theoretically more complete variance/covariance structure of the multivariate Poisson model, based on domain knowledge or preliminary statistical analysis of significant purchase interaction effects in the data. Consequently, the model does not contain more parameters than necessary, whilst still accounting for the existing covariance in the data. Practically, retail category managers can use the model to devise customized merchandising strategies.     

Cross-ownership as a structural explanation for over- and underestimation of default probability

Based on the work of Suzuki, we consider a generalization of Merton’s asset valuation approach in which two firms are linked by cross-ownership of equity and liabilities. Suzuki’s results then provide no arbitrage prices of firm values, which are derivatives of exogenous asset values. In contrast to the Merton model, the assumption of lognormally distributed assets does not result in lognormally distributed firm values, which also affects the corresponding probabilities of default. In a simulation study we see that, depending on the type of cross-ownership, the lognormal model can lead to both over- and underestimation of the actual probability of default of a firm under cross-ownership. In the limit, i.e. if the levels of cross-ownership tend to their maximum possible value, these findings can be shown theoretically as well. Furthermore, we consider the default probability of a firm in general, i.e. without a distributional assumption, and show that the lognormal model is often able to yield only a limited range of probabilities of default, while the actual probabilities may take any value between 0 and 1.     

Comparison of Mean-Risk Efficient Portfolios in Asia-Pacific Capital Markets

In order to analyze the performance of mean-risk efficient portfolios, several methods of portfolio comparison have been developed. In this paper we analyze the second-order stochastic dominance efficiency of portfolios on the mean-risk efficient frontier assuming that the risk is represented by standard deviations and concordance matrices set up on the basis of Pearson's linear correlation, Spearman's rho, or Kendall's tau. Empirical analysis of the market returns of selected Asia-Pacific stock markets is carried out considering both the U.S. dollar and euro as reference currencies, and different periods: before and during the subprime crisis. Measures and portfolios on the mean-risk efficiency frontier that should be of interest to at least one risk-averse investor are empirically documented.     

Creating a Testable, Estimable Model to Inform Our Response to the Test-Score Gap Crisis

The test-score gap between black and white students should be seen as a crisis. We propose a testable model based on readily available data that will allow us to estimate the impact and interrelationships of a multitude of factors that may be partially responsible for the problem. The estimation of this model will require the joint efforts of experts in many areas of education as well as of experts in multilevel structural equation modeling.     

A panel data analysis of code-sharing,antitrust immunity,and open skies treaties in international aviation markets

This paper estimates the effects of code-sharing, antitrust immunity, and Open Skies treaties on prices, output, and capacity using an eleven-year panel of U.S.-Europe data. Code-sharing and immunized alliances are found to have significantly lower prices than does traditional interline (multi-carrier) service, but the effects are smaller in magnitude than those found in previous results that rely on cross-sectional data. Statistical tests that prices for immunized alliance service are equal to online (single carrier) service often cannot be rejected, providing additional evidence that immunity grants allow immunized carriers to internalize a double marginalization problem. Estimated output effects, consistent with the price effects, show that alliances are associated with large increases in passenger volumes. Lastly, estimates suggest that capacity expansions associated with “Open Skies” treaties are due entirely to expansion by immunized carriers on routes between their hubs. I would like to thank the editor and an anonymous referee for their helpful comments. The views expressed in this paper do not reflect those of the US Department of Justice. All errors are my own