Evaluating the performance of Brazilian university hospitals

In order to demonstrate how DEA modeling can be helpful to aid decision making relative to the Brazilian Teaching Hospital Policy by means of hospital performance assessment, we develop a case study with 30 general hospitals linked to Brazilian Federal Universities. We consider data on medical care (Medical Model—MM), teaching and research (Teaching-Research Model—TRM) and use the software IDEAL (Interactive Data Envelopment Analysis Laboratory) as a tool for the units’ efficiency evaluation. IDEAL, developed in Brazil, is unique in providing a 3-D frontiers visualization, assisting in exploratory analysis and allowing a better understanding of the DEA modeling (envelopment and multiplier). Both models are input-oriented and each hospital is categorized according to its relative efficiency in the MM and TRM. In this phase, it is very important to discuss with the decision-makers the results and patterns of the DEA models. Finally, the modelling indicates the necessary changes for the inefficient units and generates recommendations for teaching ratios and public financing.     

Non-cooperative investment in partnerships and their termination

This paper investigates how partners (firms or husband and wife) should invest into an uncertain stock that provides a common good, when to stop investments and when to end their partnership. The assumption of lumpy investments leads to a real option problem which is solved for the cooperative and non-cooperative solutions. Yet despite the analytical solution, numerical means are necessary to investigate economic consequences: strong incentives to free ride under competition even turning one of the options—to stop investment at high stock levels—into one of a negative value; in contrast, divorce remains a positively valued option.     

Software for the analysis of extreme events: The current state and future directions

The last few years have seen a significant increase in publicly available software specifically targeted to the analysis of extreme values. This reflects the increase in the use of extreme value methodology by the general statistical community. The software that is available for the analysis of extremes has evolved in essentially independent units, with most forming extensions of larger software environments. An inevitable consequence is that these units are spread about the statistical landscape. Scientists seeking to apply extreme value methods must spend considerable time and effort in determining whether the currently available software can be usefully applied to a given problem. We attempt to simplify this process by reviewing the current state, and suggest future approaches for software development. These suggestions aim to provide a basis for an initiative leading to the successful creation and distribution of a flexible and extensible set of tools for extreme value practitioners and researchers alike. In particular, we propose a collaborative framework for which cooperation between developers is of fundamental importance. AMS 2000 Subject Classification Primary—62P99     

基于数据包络分析的企业资本利用有效性研究

数据包络分析(DEA)是一种评价相对有效性的线性规划方法，在多个输入、多个输出情形下的投入产出效率分析中多有应用，并可进行规模效应分析。本采用DEA方法，以沪深股市50家房地产上市公司为样本。采用其2002年度财务数据，对样本公司资本利用的有效性进行了实证分析。研究表明，我国多数房地产上市公司既存在着显的技术非有效，也存在着显的规模非有效；其中，主营业务收入5亿元以上的公司一般运行在规模效益递减区间，这意味着并不是最大的公司具有最好的资本利用有效性。     

Pairwise comparison matrices and the error-free property of the decision maker

Pairwise comparison is a popular assessment method either for deriving criteria-weights or for evaluating alternatives according to a given criterion. In real-world applications consistency of the comparisons rarely happens: intransitivity can occur. The aim of the paper is to discuss the relationship between the consistency of the decision maker—described with the error-free property—and the consistency of the pairwise comparison matrix (PCM). The concept of error-free matrix is used to demonstrate that consistency of the PCM is not a sufficient condition of the error-free property of the decision maker. Informed and uninformed decision makers are defined. In the first stage of an assessment method a consistent or near-consistent matrix should be achieved: detecting, measuring and improving consistency are part of any procedure with both types of decision makers. In the second stage additional information are needed to reveal the decision maker’s real preferences. Interactive questioning procedures are recommended to reach that goal.     

The effectiveness of corporate governance: board structure and business technical efficiency in Spain

This study seeks to determine the effectiveness of corporate governance by analyzing the impact of board structure on firm technical efficiency. Resampling methods and bootstrapping techniques applied in Data Envelopment Analysis are used to evaluate firm performance. Truncated regressions are estimated to determine the effect of five board characteristics—board size, board independence, board reputation, board diversity and board activity—on efficiency. The result of this empirical study shows that business technical efficiency increases with a heterogeneous board with a limited number of directorships per director and with a limited activity specified in a reduced number of annual board meetings with a higher number of specialized committees.     

Image synthesis for autostereoscopic systems

The article considers image synthesis for autostereoscopic systems — systems that enable the viewer to perceive three-dimensional images without any special devices, such as glasses. The general image synthesis problem for such systems is stated and an efficient algorithm is proposed for its solution. Some applications of the proposed methodology for two types of units are described: a stereo display and a stereo projection system. We examine the optimization of technical system parameters with the objective of enlarging the region where the viewer sees a three-dimensional image.     

Computer cartography point-in-polygon programs

The official statistics and census reports give figures only for administrative units. The boundaries of these units are often changed and hence it is very difficult to compare statistics from two different periods. However, an administrative unit can always be approximated by a polygon. Real estate data are assigned to a central point for which the coordinates are known. A computer can determine whether a point belongs to a polygon or not by means of a special program. Data for all real estate central points belonging to the actual polygon are added. In this way it will be possible to compute data for arbitrary polygons, for instance administrative units which do not exist any longer, by assigning real estate data to the central points.     

房地产开发的最优时间和最优强度

房地产投资具有许多不确定性,对房地产投资进行评估尤为重要.利用实物期权理论,对房地产投资进行建模分析,确定出最优开发时间和最优开发强度;最后根据模型推导出来的结论进行数值分析.     

Improving envelopment in Data Envelopment Analysis under variable returns to scale

In a Data Envelopment Analysis model, some of the weights used to compute the efficiency of a unit can have zero or negligible value despite of the importance of the corresponding input or output. This paper offers an approach to preventing inputs and outputs from being ignored in the DEA assessment under the multiple input and output VRS environment, building on an approach introduced in Allen and Thanassoulis (2004) for single input multiple output CRS cases. The proposed method is based on the idea of introducing unobserved DMUs created by adjusting input and output levels of certain observed relatively efficient DMUs, in a manner which reflects a combination of technical information and the decision maker’s value judgements. In contrast to many alternative techniques used to constrain weights and/or improve envelopment in DEA, this approach allows one to impose local information on production trade-offs, which are in line with the general VRS technology. The suggested procedure is illustrated using real data.     

住宅房地产顾客感知价值评估

不同的顾客对同一住宅房地产的感知价值是不同的,购房决策主要取决于对住宅房地产的顾客感知价值.提出了住宅房地产顾客感知价值评估的质量功能配置逆过程法,在已知住宅房地产工程特性的条件下,确定顾客需求值.利用该方法,给出了评估住宅房地产的顾客感知价值的过程和数学模型,案例研究表明,方法能有效评估住宅房地产的顾客感知价值,帮助购房者选择住宅房地产项目.     

Multiple-attribute decision support system based on fuzzy logic for performance assessment

This paper deals with the problem of assessing the performance of a set of production units, simultaneously considering different kinds of information, yielded by a Data Envelopment Analysis, a qualitative data analysis and an expert assessment. The tool for integrating heterogeneous data is a model that applies fuzzy logic to decision support systems. The results obtained are a holistic performance assessment of each unit of the set and a ranking order of the units.     

On the cutting stock problem under stochastic demand

This paper addresses the one-dimensional cutting stock problem when demand is a random variable. The problem is formulated as a two-stage stochastic nonlinear program with recourse. The first stage decision variables are the number of objects to be cut according to a cutting pattern. The second stage decision variables are the number of holding or backordering items due to the decisions made in the first stage. The problem’s objective is to minimize the total expected cost incurred in both stages, due to waste and holding or backordering penalties. A Simplex-based method with column generation is proposed for solving a linear relaxation of the resulting optimization problem. The proposed method is evaluated by using two well-known measures of uncertainty effects in stochastic programming: the value of stochastic solution—VSS—and the expected value of perfect information—EVPI. The optimal two-stage solution is shown to be more effective than the alternative wait-and-see and expected value approaches, even under small variations in the parameters of the problem.     

Maturity,distance and density (MD<Superscript>2</Superscript>) metrics for optimizing trust prediction for business intelligence

The modelling and management of trust between interacting parties are crucial parts of the overall business intelligence strategy for any organization. Predicting trust values is a key element of modelling and managing trust. It is of critical importance when the interaction is to be conducted at a future point in time. In the existing body of work, there are a few approaches for predicting trust. However, none of these approaches proposes a framework or methodology by which the predicted trust value can be considered in light of its accuracy or confidence level. This is a key element in order to ensure optimized trust prediction. In this paper, we propose a methodology to address this critical issue. The methodology comprises a suite of metrics—maturity, distance and density (MD²) which are capable of capturing various aspects of the confidence level in the predicted trust value. The proposed methodology is exemplified with the help of case studies.     

基于MIV-BP型网络实验的房地产项目风险识别研究

为了更准确更客观地识别房地产项目中的风险,为房地产项目投资决策提供科学依据和参考,有效地规避风险,本研究在BP神经网络 (Back-Propagation Neural Network)建模的基础上,采取MIV(Mean Impact Value)算法对BP神经网络模型进行变量筛选的网络优化和改良,从而形成新的优化后的MIV-BP(Mean Impact Value Back-Propagation Neural Network)神经网络,并以此用于评价房地产项目中的风险度以及各因素在风险度中的影响作用大小;同时选取目前相关的房地产项目数据进行仿真实证分析和验证。验证实验结果表明,MIV-BP型神经网络对于房地产项目风险度识别具有良好的适应性和准确性,实验结果客观,达到专家评价的要求,并在风险因素作用度分析上具有良好的应用价值。     

Approximation of impulse controls

The application of impulse controls—delta-function and its higher derivatives—essentially improves our ability to control various systems. However, the delta-function and its derivatives are “idealizations.” Controls applied to model and control real systems are finite (although possibly quite large in magnitude). In this article we consider bounded approximations of impulse controls—so-called fast controls—and examine methods of their construction.     

A Minimum-Cost Analysts Assignment Model for Asset Evaluation of Insolvent Saving and Loan Institutions

Audit staff planning has been a challenging problem for accounting, auditing and real estate firms. This paper presents a mathematical model and a solution methodology for determining the minimum-cost analysts assignment, when analysts should travel from geographically dispersed locations to evaluate assets of an insolvent Saving and Loan institution. Computational experiments with the solution algorithm on 27 randomly generated projects show (a) that the solution methodology efficiently generates an optimal solution, and (b) provides the decision maker with alternative next best plans through ex post sensitivity analysis. Although specific, variations of the model and algorithm presented here can be applied to a variety of audit staff assignment problems in accounting and real estate firms.     

Real estate price estimation in French cities using geocoding and machine learning

This paper reviews real estate price estimation in France, a market that has received little attention. We compare seven popular machine learning techniques by proposing a different approach that quantifies the relevance of location features in real estate price estimation with high and fine levels of granularity. We take advantage of a newly available open dataset provided by the French government that contains 5 years of historical data of real estate transactions. At a high level of granularity, we obtain important differences regarding the models’ prediction powers between cities with medium and high standards of living (precision differences beyond 70% in some cases). At a low level of granularity, we use geocoding to add precise geographical location features to the machine learning algorithm inputs. We obtain important improvements regarding the models’ forecasting powers relative to models trained without these features (improvements beyond 50% for some forecasting error measures). Our results also reveal that neural networks and random forest techniques particularly outperform other methods when geocoding features are not accounted for, while random forest, adaboost and gradient boosting perform well when geocoding features are considered. For identifying opportunities in the real estate market through real estate price prediction, our results can be of particular interest. They can also serve as a basis for price assessment in revenue management for durable and non-replenishable products such as real estate.

     

Mapping of a half-plane onto a polygon with infinitely many vertices

In this paper we generalize the Schwarz—Christoffel formula for a conformal mapping of a half-plane onto a certain polygon with infinitely many vertices. We assume that the interior angles of the polygon (at unknown vertices) and the points of the real axis that are images of unknown vertices under the mentioned mapping are given.     

《新拆迁条例》下商业性拆迁突发事件的演化机理与影响因素

《新拆迁条例》规范了房屋征收部门和房地产开发商、被征收入的拆迁补偿行为.运用演化博弈研究了城市商业性拆迁过程中开发商与被拆迁户之间行为特征,以及不同收益约束下各种均衡演化结果:开发商和被拆迁户均采取强硬策略导致群体性突发事件爆发;少数"钉子户"提出过分补偿要求迫使开发商接受;开发商采取暴力拆迁策略损害被拆迁户合法权益.进而讨论了政府部门提供外生性制度安排介入到城市商业性拆迁过程.政府部门在城市商业性拆迁事件中决策需要考虑多种因素的权衡.其中,逐步摆脱"土地财政"依赖,依法实施《新拆迁条例》禁止开发商的暴力拆迁行为,促使少数补偿标准期望值过高的"钉子户"回归理性态度,有利于双方达成理性双赢的(协商拆迁,让步同意)的演化均衡结果.