整合技术概念及对新古典就业理论的反思

笔者提出整合技术概念，即所有的工人整合在一起操作生产系统；如果任何一名工人缺失，则生产系统不能运行。如果一种技术严格具有整合技术的性质，那么在到达能使生产系统运行之前，工人的边际产品为零。如果增加一名工人生产系统就可运行，则这名工人的边际产品等于总产品。如果再增加一名工人的边际产品为零，则边际产品曲线退化为一条垂直线。新古典边际劳动生产率理论认为，厂商雇闸工人的工资等于劳动的边际产品，但这一理论显然不适合整合技术。因此，要研究在更一般条件下厂商雇用决策的机制。采用整合技术的概念可以对很多经济学的理论问题进行重新思考。     

Nonparametric estimators of the bivariate survival function under random censoring

A large number of proposals for estimating the bivariate survival function under random censoring have been made. In this paper we discuss the most prominent estimators, where prominent is meant in the sense that they are best for practical use; Dabrowska's estimator, the Prentice–Cai estimator, Pruitt's modified EM-estimator, and the reduced data NPMLE of van der Laan. We show how these estimators are computed and present their intuitive background. The asymptotic results are summarized. Furthermore, we give a summary of the practical performance of the estimators under different levels of dependence and censoring based on extensive simulation results. This leads also to a practical advise.     

The Russian option: Finite horizon

We show that the optimal stopping boundary for the Russian option with finite horizon can be characterized as the unique solution of a nonlinear integral equation arising from the early exercise premium representation (an explicit formula for the arbitrage-free price in terms of the optimal stopping boundary having a clear economic interpretation). The results obtained stand in a complete parallel with the best known results on the American put option with finite horizon. The key argument in the proof relies upon a local time-space formula.Received: March 2004, Mathematics Subject Classification (2000): 91B28, 35R35, 45G10, 60G40, 60J60JEL Classification: G13Goran Peskir: Centre for Analytical Finance (funded by the Danish Social Science Research Council) and Network in Mathematical Physics and Stochastics (funded by the Danish National Research Foundation).The first draft of the present paper has been completed in September 2002. I am indebted to Albert Shiryaev for useful comments.     

遗传算法在拖轮调度中的应用

根据某港口的实际情况,分析拖轮工作的工作过程和特点,以拖轮编号作为编码形式,将遗传算法应用到拖轮调度系统中,实现优化调度,提高拖轮作业的效率。     

An assessment of the interruption level of doctors in outpatient appointment scheduling

Interruptions to the server in an outpatient clinic environment have received limited attention in the appointment scheduling literature. However, explicitly modeling interruptions on the part of the doctor may have an impact on the optimal appointment schedule and consequently, on patient waiting times. This is explored with a simulation optimization model that is based on data from time studies and interviews with medical professionals from multiple outpatient clinics. The results show a “plateau-dome” scheduling rule for practical implementation to be robust for low interruption rates and a traditional dome pattern for higher levels of interruptions. In addition, if clinic operations are such that doctors are able to adjust their behavior to complete all work during the session, then the schedule is invariant to changes in the interruption rate.     

闸墩门槽二期整体式滑模施工技术

长洲水利枢纽外江泄水闸工程是整个外江工程关键性工期的保证工程,由于遭遇2006年洪水,外江工程进度严重滞后,需要对原施工方案进行优化。整体式滑模施工技术具有施工进度快,保证二期混凝土施工质量,克服了常规单边门槽滑模的缺点等优势,据此,文章阐述了整体式滑模施工的技术要点。     

An empirical analysis of airport capacity expansion

Theoretical analyses of the impact of airport capacity expansion must model or make assumptions about the effect of capacity on demand, airline competition, aircraft types, fares and other characteristics of a given airport. In this paper, we use empirical data on historical schedules, fares, delays and demand for the busiest 150 airports in 2015 to examine the typical impact of historical capacity expansions. We find significant diversity in outcomes, with over half the expanded airports either using less than their pre-expansion capacity or remaining constrained even at post-expansion capacity by 2016. Many of the expected impacts, such as reductions in typical aircraft size, either do not materialise or are dominated by other effects (for example, recessions; airlines beginning or ending operations at an airport; changes in regulation). Behaviour on expansion is affected by slot control regulations and whether the airport is initially capacity-constrained. In particular, slot-controlled airports typically add new destinations and carriers on expansion rather than making significant changes to existing schedules.     

Criteria selection and multi-objective optimization of aircraft landing problem

Inspired by the similarities of the aircraft landing problem (ALP) and the single machine scheduling problem, we propose a criteria selection method that has been used successfully in the single machine scheduling problem to determine appropriate objective functions of ALP. First, for four different types of criteria—min-max, min-sum, completion time related, and due-dates related criteria—their corresponding physical meanings in ALP are elaborated. Then, a criteria selection method is proposed to determine several appropriate criteria, which are taken as the multi-objective while modeling ALP. Different solution algorithms, including Imperialist Competitive Algorithm (ICA), are adopted to solve the multi-objective ALP. Finally, the performance of the proposed model and method are evaluated using a set of benchmark instances. The computational results demonstrate the efficiency of our approach for solving ALP, which can simultaneously improve punctual performance, enhance runway utilization, reduce air traffic controller workload, and maintain equity among airlines.     

Knowledge acquisition using psychotherapy technique for critical factors influencing construction project layout planning

The positioning of equipment on a construction site may change in different construction phases, different environments, and different types of end products, which greatly influence the decision of the site planning engineer who seeks to maximize the construction efficiency by minimizing the friction from the site layout. This study aims to acquire and analyze site planning experts' knowledge on critical factors influencing the construction layout planning using a psychotherapy technique. Through an open‐structured interview survey and cluster analysis, 125 core factors influencing the site layout plan were analyzed and categorized into a database.     

Cooperation support through the use of group decision systems

This article considers the development of the group decision support system (GDSS) field both from organizational and technological perspectives. The growing importance of teamwork, lateral coordination, and activities integration inside modern business organizations is emphasized. Technological and knowledge specialization, quick transformation of business environments, reduction of response time, and so on, are some of the reasons that can explain the renewed relevance of teamwork. Also, the development of information technology (IT) is analyzed in relation to the role it is assuming in supporting group activities. Research in the GDSS field is then introduced. A proposal concerning the identification of three different phases in GDSS studies is developed, ranging from decision rooms to distributed systems. Each phase shows distinctive research topics and application fields, together with different organizational goals. Results of these developments are the growth of potential application areas of GDSS tools. These theoretical considerations, together with empirical experiences coming from the study of a real manufacturing environment (an IBM plant where group cooperation plays a fundamental role for production efficiency), constitute the basis for a research GDSS prototype (GROUPS). Prototype features are designed to support executives in facing production‐planning problems through an improvement in communications and in knowledge representation.