Operations research in the management of the airlines

This paper is intended to present an introduction to the use of operations research in the international airline industry, and to demonstrate the scope and significance of the airline OR activities. First, the special reasons for the viability and spread of airline OR are discussed. Then a functional framework for an airline is outlined, to be used in analyzing the problems of an airline and relating the OR work to it. Four major applications are described, corresponding to four major components of the framework. These applications are: schedule development, overbooking control, crew scheduling and engine management, respectively. In each case we describe the problem and its significance, indicate the types of solution techniques which have been developed, and assess the implemented solutions. The paper concludes with comments on the current state-of-the-art and the future of airline OR. A detailed bibliography is given.Both of the authors have been operations research directors in major airlines and more recently have focused their attention upon the industry as academic researchers. This background has provided us with an unusual opportunity to analyze the role of OR in the airlines, and our paper seeks to share with the reader some of the insights we have gained thereby.     

Identifying rational distributed lag models using a joint test applied to the corner table

Often a distributed lag response pattern can be usefully represented in rational polynomial form. When the impulse response function decays, the corner table may be useful for model identification if appropriate statistical tests may be done. One or more joint tests are called for since use of the corner table involves studying groups of its elements. We consider an asymptotic x2 statistic that permits joint tests. We report simulation results showing that the distribution of this statistic follows the x ² distribution, for certain sample sizes and degrees of freedom, well enough to be useful in practice. With two data sets we illustrate how this statistic can be a useful aid when using the corner table.     

股东参与治理的私人收益和社会收益的实证研究

本文探讨了股东参与治理所带来的私人收益、特定股权结构的社会收益以及股权集中成本三者之间的关系。我们分析的结果表明,当股东与经理人员之间的利益冲突水平较高、其它治理机制的作用较弱时,股权集中(股东参与治理的积极性较高)可以创造大量的社会收益;反之,股权的集中与分散程度(股东参与治理的积极性较低)对社会收益的影响不明显。本文的研究结论为我国股东参与治理及股权结构改革提供了重要启示。     

Teachers' delivery skills and substance use prevention program outcomes: the moderating role of students' need for cognition and impulse decision making

The purpose of this study was to extend the literature in both substance use implementation and persuasive health communication by examining the extent to which students' need for cognition and impulsive decision-making moderated the relationship between teachers' classroom communication behavior and program outcomes in an evidence-based middle school substance use prevention curriculum. Participants included 48 teachers and their respective 7th grade students who participated in a randomized trial testing the effectiveness of personal coaching as a means to improve the quality with which teachers implemented the All Stars curriculum. Need for cognition and impulse decision-making were both associated with positive changes in lifestyle incongruence and commitments to not use substances for students whose teachers displayed greater interactive teaching. Further, need for cognition was associated with lower alcohol use rates while impulse decision making related to lower rates of marijuana use in classes with interactive teaching.     

Implementation fidelity in a teacher-led alcohol use prevention curriculum

There is now ample evidence that teachers tend to make substantial modifications to both the prescribed content and methods of the curricula they administer, and that such modifications are likely to attenuate curricula effects. We examine the fidelity with which teachers implement "Protecting You, Protecting Me," an underage alcohol use prevention curriculum. Findings suggest that while teachers attempted to implement most sections of a lesson, the lessons taught were consistently--and often extensively--adapted. We conclude that since teachers are likely to continue to modify lessons, curriculum developers and trainers should enhance their understanding of how prevention curricula are taught under real world conditions, help teachers to reinforce key curriculum concepts, and consider modifying those curricular sections that teachers are adapting with greatest frequency.