The law of one price in data envelopment analysis: Restricting weight flexibility across firms

The Law of One Price (LoOP) states that all firms face the same prices for their inputs and outputs under market equilibrium. Taken here as a normative condition for ‘efficiency prices’, this law has powerful implications for productive efficiency analysis, which have remained unexploited thus far. This paper shows how LoOP-based weight restrictions can be incorporated in Data Envelopment Analysis (DEA). Utilizing the relation between industry-level and firm-level cost efficiency measures, we propose to apply a set of input prices that is common for all firms and that maximizes the cost efficiency of the industry. Our framework allows for firm-specific output weights and for variable returns-to-scale, and preserves the linear programming structure of the standard DEA. We apply the proposed methodology to the evaluation of the research efficiency of economics departments of Dutch Universities. This application shows that the methodology is computationally tractable for practical efficiency analysis, and that it helps in deepening the DEA analysis.     

Differential games of fixed duration with state constraints

We consider differential games of fixed duration with phase coordinate restrictions on the players. Results of Ref. 1 on games with phase restrictions on only one of the players are extended. Using Berkovitz's definition of a game (Ref. 2), we prove the existence and continuity (or Lipschitz continuity) of the value under appropriate assumptions. We also note that the value can be characterized as the viscosity solution of the associated Hamilton-Jacobi-Isaacs equation.This work comprises a part of the author's PhD Thesis completed at Purdue University under the direction of Professor L. D. Berkovitz. The author wishes to thank Professor Berkovitz for suggesting the problem and many valuable discussions. During the research for this work, the author was supported by a David Ross Grant from Purdue University as well as by NSF Grant No. DMS-87-00813.     

SEM Modeling with Singular Moment Matrices Part II: ML-Estimation of Sampled Stochastic Differential Equations

Linear stochastic differential equations are expressed as an exact discrete model (EDM) and estimated with structural equation models (SEMs) and the Kalman filter (KF) algorithm. The oversampling approach is introduced in order to formulate the EDM on a time grid which is finer than the sampling intervals. This leads to a simple computation of the nonlinear parameter functionals of the EDM. For small discretization intervals, the functionals can be linearized, and standard software permitting only linear parameter restrictions can be used. However, in this case the SEM approach must handle large matrices leading to degraded performance and possible numerical problems. The methods are compared using coupled linear random oscillators with time-varying parameters and irregular sampling times.     

关于带时间约束的单机排序的一个注记

研究单机带时间B-约束的排序问题,即在任意单位时间区间[x,x+1）内至多允许加工B个工件,目标函数是极小化工件的最大完工时间.分析了B=2时最优排序的结构与性质,设计了O（n log n）时间的启发式算法.当工件数较少（≤ 6）时,证明了该算法的最优性.     

Unattended acoustic events classification at the vicinity of airports

This paper describes a method for the automatic identification of acoustic events using a weighted average of sound pressure and sound intensity measured at the vicinity of airports. The classification is based on the combination of different parameters using a technique conceptually similar to the sensor fusion: the indications of different classifiers are merged using the classification uncertainty as a figure of merit. The method uses the results of a training phase for the observation of statistical distributions of sound pressure and sound intensity related parameters. The different parameters’ weights are computed analyzing the overlap of probability distributions of takeoffs and landings, so that more relevance is given to the quantities presenting a low risk of misclassification. The proposed method does not require any arbitrary assumption about the parameter effectiveness, given that the indications of multiple (potentially infinite) classifiers can be merged together with weights that minimize the chance of misclassification. The method has been validated with measurements performed at the Milan Malpensa airport (Italy). Results outlined that the proposed classification criterion correctly identifies approximately 99% of events.     

偏好约束锥DEA模型在工业企业创新效率评价中的应用

为解决工业企业创新活动中的创新效率评价方法不能同时兼顾定量与定性分析的问题,结合现有的创新效率评价的方法,以及评价中既要依赖客观数据又要反映决策者偏好的评价准则特点,构建了带有偏好锥的DEA模型,并建立了相应的创新效率投入产出指标体系.利用该模型和体系对创新效率评价方法进行了研究,最后以重庆市2007年工业企业创新统计数据为依据,对8个不同类型企业的创新效率进行了评价.研究表明:该方法能反映决策者的偏好,解决了定量与定性分析相结合的问题.     

π-σ轨道作用能分解法和限制万轨道作用的几何优化

简要地介绍能量分解法的发展历史，强调能量分解的特点是给量子化学的计算提供明确的化学意义，介绍本实验室建立的能量分解法和限制轨道作用的几何优化法。在这两个方法的基础上，论证了丌．电子离域是失稳定的；颠倒了经典有机结构理论中基本的因果关系——共轭效应和构象之间的因果关系；为芳香能的计算提供了一个新的模型和新的方法，表明芳香能的计算不再需要参考分子；定量地区别静电作用和电子离域在化学键形成中的作用；定量地讨论取代基效应和张力芳环的扭曲驱动力。     

网络最大流的"冲塞式"求法

网络最大流的理论与方法在运输与网络管理中有着重要的应用。受在管道中冲塞物体的原理的启发，本提出了一种新的求解网络最大流的方法，该方法较以往的解法有一些特别的优点。     

On ratio-based RTS determination: An extension

This technical note extends the results of our recent paper [Korhonen, Soleimani-damaneh, Wallenius, EJOR 215 (2011) 431–438], for determining the RTS status of Decision Making Units in Weight-Restricted DEA models.