A note on integer-valued radial model in DEA

This note shows that the input targets of proposed model by Kuosmanen and Kazemi Matin (2009) (http://dx.doi.org/10.1016/j.ejor.2007.09.040 and http://dx.doi.org/10.1016/j.omega.2008.11.002) may not be less than the input targets of proposed model by Lozano and Villa (2006) (http://dx.doi.org/10.1016/j.cor.2005.02.031).     

A note on graph balancing problems with restrictions

We consider the graph balancing problem of providing orientations to edges in an undirected multi-graph to minimize the maximum load. We first obtain an FPTAS when the multi-graph is restricted to a tree. We also obtain some additional results for other restricted cases by showing equivalencies with related combinatorial problems.     

A technical note on “A note on integer-valued radial model in DEA”

Khezrimotlagh et al. (2013) pointed out the Kuosmanen and Kazemi Matin’s model (hereafter referred to as, the KKM model) may not be stronger than the Lozano and Villa’s model (hereafter referred to as, the LVM model), and they used a counter example to show that the input targets of the KKM model may even be greater than that of the LVM model. In this paper, we improved the KKM model into a rectified KKM model (hereafter referred to as, the RKKM model), and showed that the RKKM model can successfully solve the problem in the counter example.     

A note on a new method based on the dispersion of weights in data envelopment analysis

In a very recent paper by Bal et al. (Bal, H., Örkcü, H. H., & Çelebioğlu, S. (2008). A new method based on the dispersion of weights in data envelopment analysis. Computers & Industrial Engineering, 54(3), 502–512), a data envelopment analysis (DEA) model which incorporates the coefficients of variations (CVs) of input–output weights was proposed to improve the discrimination power of DEA and balance input–output weights. This note points out that the input and output weights in DEA are of different dimensions and units. The weights with different dimensions and units cannot be simply added together and averaged. In other words, the DEA model with the inclusion of CVs of input–output weights, which was referred to as CVDEA model for short, makes no sense if input and output data are not normalized to eliminate their dimensions and units. This note also illustrates the facts that the CVDEA model can cause significant efficiency changes when a scale transformation is performed for an input or output and may produce multiple local optimal solutions due to its nonlinearity, leading to totally different assessment conclusions. These facts reveal that the CVDEA model suffers from serious drawbacks and its applications for efficiency assessment should be very cautious.     

Step-by-step improvement of MPS method in simulating violent free-surface motions and impact-loads

The violent free-surface motions and the corresponding impact loads are numerically simulated by using the Moving Particle Semi-implicit (MPS) method, which was originally proposed by Koshizuka and Oka [10] for incompressible flows. In the original MPS method, there were several defects including non-optimal source term, gradient and collision models, and search of free-surface particles, which led to less-accurate fluid motions and non-physical pressure fluctuations. In the present study, how those defects can be remedied is illustrated by step-by-step improvements in the respective processes of the revised MPS method. For illustration, two examples are studied; (i) dam breaking problem and (ii) liquid sloshing inside a rectangular tank. The improvement of each step is explained and numerically demonstrated. The numerical results are also compared against the experimental results of Martin and Moyce [12] for dam-breaking problem and Kishev et al. [9] for sloshing problem. The numerical results for violent free-surface motions and impact pressures are in good agreement with their experimental data.     

Common sets of weights as summaries of DEA profiles of weights: With an application to the ranking of professional tennis players

In this paper, we propose a DEA approach aimed at deriving a common set of weights (CSW) to be used to the ranking of decision making units (DMUs). The idea of this approach is to minimize the deviations of the CSW from the DEA profiles of weights without zeros of the efficient DMUs. This minimization reduces in particular the differences between the DEA profiles of weights that are chosen, so the CSW proposed is a representative summary of such DEA weights profiles. We use several norms to the measurement of such differences. As a result, the CSWs derived are actually different summaries of the chosen DEA profiles of weights like their average profile of their median profile. This approach is illustrated with an application to the ranking of professional tennis players.     

A note on some alternative DEA models for two-stage process

In a recent paper in this journal by Wang and Chin (2010), they transformed a two-stage process into a single process. However, we find that Fig. 2 in Wang and Chin (2010) ignored the relationship between two processes when the single process was treated as a black box, which can misguide the decision maker. In this paper, the Fig. 2 in Wang and Chin (2010) is corrected, and a new transformation is proposed which transforms a two-stage process to a single process with two independent parallel sub-processes. The relationship between Chen, Cook, Li, and Zhu (2009)’s model and models (22) in Wang and Chin (2010) is also discussed.     

基于优化组合权与云-VIKOR法的PFMEA风险评估分析与改进

针对过程失效模式与影响分析（PFMEA）风险评估过程专家评估信息的模糊性与随机性,引入云模型将其量化为云语义评估信息,并集结成综合云评价矩阵。针对传统客观加权法不考虑风险因子间相互影响关系的问题,提出改进熵权与云-DEMATEL优化组合求解风险因子权重,其中引入云相似度算法对专家的云评价结果进行精确化处理,避免了评估信息定量转换过程信息的缺失。根据云距离测量法计算每种故障模式与正、负理想解之间的距离,进而提出云-VIKOR法求得各失效模式的风险排序。最后,通过案例分析验证了所提方法的可行性。     

Maximum appreciative cross-efficiency in DEA: A new ranking method

Ranking decision making units (DMUs) is one of the most important applications of data envelopment analysis (DEA). In this paper, we exploit the power of individual appreciativeness in developing a methodology that combines cross-evaluation, preference voting and ordered weighted averaging (OWA). We show that each stage of the proposed methodology enhances discrimination among DMUs while offering more flexibility to the decision process. Our approach is illustrated through an example involving 15 baseball players.     

Optimal project feature weights in analogy-based cost estimation: improvement and limitations

Cost estimation is a vital task in most important software project decisions such as resource allocation and bidding. Analogy-based cost estimation is particularly transparent, as it relies on historical information from similar past projects, whereby similarities are determined by comparing the projects' key attributes and features. However, one crucial aspect of the analogy-based method is not yet fully accounted for: the different impact or weighting of a project's various features. Current approaches either try to find the dominant features or require experts to weight the features. Neither of these yields optimal estimation performance. Therefore, we propose to allocate separate weights to each project feature and to find the optimal weights by extensive search. We test this approach on several real-world data sets and measure the improvements with commonly used quality metrics. We find that this method 1) increases estimation accuracy and reliability, 2) reduces the model's volatility and, thus, is likely to increase its acceptance in practice, and 3) indicates upper limits for analogy-based estimation quality as measured by standard metrics.     

无线传感器网络中一种模糊加权目标定位方法

提出了一种无线传感器网络( WSNs)中的模糊加权定位算法,利用探测节点RSSl值的估计距离为平面离散栅格分配权值,通过比较累计权值搜索出目标坐标,其模糊性使得该方法能够有效地抵抗各种强度的噪声,设定可调模糊度适应不同的衰落信道,在单目标定位中具有非常高的稳定性.针对多目标定位,提出变型的权值模型,设计了去模糊化算法将多个目标坐标提取出来.对实验仿真结果作出了评估,并提出了多目标定位的限制条件.     

A target-oriented DEA model for regional construction productive efficiency improvement in China

China’s construction industry is a major contributor to economic growth during the past decade, but the industry has been mainly investment-driven without significant productivity improvement yet with high disparity across different regions. In the context of unbalanced regional development and resource allocation, stagnant performance of construction productivity is a common concern hindering the rapid and sustainable development of regional construction industry. The long-standing and escalating regional differences would not only undermine the overall performance of construction productivity, also lead to inefficient resource allocation and inappropriate target settings for future development. To address these issues, this study developed an overall efficiency measurement model for the construction industry, and then applied a Target-Oriented (TO) Data Envelopment Analysis (DEA) model to identify the optimal pathways for low efficiency provinces with the achievement of stage-wise targets in different regions of China. Comparison was made on construction productive efficiency, resource utilization, and recommendations were made for further improvement in three regions with different levels of economic development. The analytical and empirical results can provide insightful information for policy making and strategic planning with progressive efficiency improvement of regional construction industry of China.     

A note on the receding-horizon control method

In this correspondence, the relation of receding-horizon control method with the state deadbeat control is brought out. It is shown for single-input systems that the receding-horizon control is a state deadbeat control if the horizon length is taken to be equal to the state dimension.     

A note on a computer-aided root-locus method

It is shown that the computer-aided root-locus method suggested by Pan and Chao [3] can be more efficient, reducing cumbersome complex arithmetics, if one incorporates the Bairstow technique for finding roots of real polynomials.     

A new method of obtaining the priority weights from an interval fuzzy preference relation

In analyzing a multiple criteria decision-making problem, the decision maker may express her/his opinions as an interval fuzzy or multiplicative preference relation. Then it is an interesting and important issue to investigate the consistency of the preference relations and obtain the reliable priority weights. In this paper, a new consistent interval fuzzy preference relation is defined, and the corresponding properties are derived. The transformation formulae between interval fuzzy and multiplicative preference relations are further given, which show that two preference relations, consistent interval fuzzy and multiplicative preference relations, can be transformed into each other. Based on the transformation formula, the definition of acceptably consistent interval fuzzy preference relation is given. Furthermore a new algorithm for obtaining the priority weights from consistent or inconsistent interval fuzzy preference relations is presented. Finally, three numerical examples are carried out to compare the results using the proposed method with those using other existing procedures. The numerical results show that the given procedure is feasible, effective and not requisite to solve any mathematical programing.     

关于多尺度法的一个注记

以van der Pol系统为例,揭示了多尺度法在求解非线性系统三次以上近似解时似乎存在的二义性问题．通过将多尺度法的结果与KBM法所得结果进行比较,指出了如何利用多尺度法求解非线性系统三次以上近似解的正确步骤．     

A new method based on the dispersion of weights in data envelopment analysis

One of the drawbacks of the data envelopment analysis (DEA) is the problem of lack of discrimination among efficient decision making units (DMUs) and hence yielding many numbers of DMUs as efficient. The main purpose of this study is to overcome this inability. In the case in which the minimization of the coefficient of variation (CV) for input–output weights is added to the DEA model, more reasonable and more homogeneous input–output weights are obtained. For this new proposed model based on the CV it is observed that the number of efficient DMUs is reduced, improving the discrimination power. When this new approach is applied to two well-known examples in the literature, and a real-world data of OECD countries, it has been seen that the new model yielded a more balanced dispersion of input–output weights and reduced the number of efficient DMUs. In addition, the applicability of the new model is tested by a simulation study.     

A note on Rutovitz' method for parallel thinning

Lü and Wang (1985) published a counterexample showing that the approach of Rutovitz (1966) for parallel thinning of digital pictures (see also Hilditch 1969, Stefanelli and Rosenfeld 1971) is not universally valid. In this paper it is shown that the example given by Lü and Wang is the only possible counterexample. A reformulation of Rutovitz' approach is suggested which does not exhibit further defects.