Alternative mixed integer linear programming models for identifying the most efficient decision making unit in data envelopment analysis

A mixed integer linear model for selecting the best decision making unit (DMU) in data envelopment analysis (DEA) has recently been proposed by Foroughi [Foroughi, A. A. (2011a). A new mixed integer linear model for selecting the best decision making units in data envelopment analysis. Computers and Industrial Engineering, 60(4), 550–554], which involves many unnecessary constraints and requires specifying an assurance region (AR) for input weights and output weights, respectively. Its selection of the best DMU is easy to be affected by outliers and may sometimes be incorrect. To avoid these drawbacks, this paper proposes three alternative mixed integer linear programming (MILP) models for identifying the most efficient DMU under different returns to scales, which contain only essential constraints and decision variables and are much simpler and more succinct than Foroughi’s. The proposed alternative MILP models can make full use of input and output information without the need of specifying any assurance regions for input and output weights to avoid zero weights, can make correct selections without being affected by outliers, and are of significant importance to the decision makers whose concerns are not DMU ranking, but the correct selection of the most efficient DMU. The potential applications of the proposed alternative MILP models and their effectiveness are illustrated with four numerical examples.     

Digital Mock-up Technology in Product Development and Research

1 Introduction Digital mock-up(DMU)technologyis a set of integratedtechnologies built onthe application of informationtechnology throughout the complete product development process .Based onthe computer model of digital prod-ucts ,Engineers can do their design works fromthe first stage of product designtoindustrial design and processplan design. The three-di mensional mathematical models replace the original physical prototype in the digitalmode si mulation,and check the original design or i…     

A digital-twin visualized architecture for Flexible Manufacturing System

The new generation of industrial 4.0 intelligent manufacturing system consists of Human-Cyber-Physical System (HCPS), integrating human with cyber and physical systems. In manufacturing, a digital-twin visualization architecture is to solve the human-machine interaction problem that concerns digital-twin modeling on the Cyber-Physical (C-P) side and on the Human-Cyber side. Although there are many related research and applications, there lacks attention in terms of full life cycle functional services and lightweight architecture. This paper presents a general architecture of digital-twin visualization for flexible manufacturing systems (FMS). How the digital-twin C-P modeling of multi-source heterogeneous information can be described is investigated and how the 3D visualized human-machine interaction with digital-twin scenario information is explored in the proposed architecture. Besides, the visualization method of high-value information, relating to the life cycle planning, design, debugging and service stages, is studied and discussed thoroughly. Also, a digital-twin modeling concept of "Geometric information (G)-Historical samples (H)-Object attribute (O)-Snapshot collection (S)-Topology constraint (T)" (GHOST) is proposed, and methods for developing virtual digital-twin scenes architecture are presented. Based on the proposed modeling concept of GHOST for digital-twin, prototypes have been developed for the general platform of digital-twin RESTful services and the cross-platform general visual mock-up software. Experimental results show that this method is effective in the FMS lifecycle in various aspects.     

DMU车体涂装工艺的开发与应用

主要介绍了出口中东地区的内燃动车组(DMU)车体外皮的涂装工艺,针对中东地区的高温、高盐雾、强紫外线、多风沙的环境特点,制定表面涂层方案并根据国际铁路联盟标准(UIC842-1、2、3、5、6)和国际铁路行业(IRIS)质量管理体系标准编制涂层的施工工艺,确保在中东地区的气候条件下,动车组涂层能够满足其功能性和装饰性的要求。     

基于VERICUT的五轴数控加工仿真研究

在VERICUT7.0环境下,实现了DMU 50V五轴加工中心加工叶片仿真的全过程。应用VERICUT的Component Tree功能建立运动学模型,应用UG软件构建了加工中心的机床模型和生成了驱动数控机床所需的NC代码,然后通过设置毛坯,配置相应的参数,实现了叶片的五轴数控加工仿真。     

DEA方法在电机生产评价中的应用

投入产出分析作为一种数量分析方法具有广泛的应用,其方法本身在实践中不断完善和丰富。特别在投入产出效率测定方面,A.Charmes,W.Wcooper和E.Rhodes在20世纪70年代末提出的DEA（Data Envelopment Analysis）,丰富了系统分析方法的内容。     

对数据包络分析中被评价的决策单元的探讨

对所给的n个决策单元来说,现有的有关数据包络分析的文献中所讨论的被评价的决策单元都是n个决策单元之一,而本文所给出的一些定理及其应用,其中被评价的决策单元可以不是n个决策单元之一。     

CATIA V5环境下的轿车车身冲压生产线仿真研究

以轿车车身冲压生产线作为研究对象，在CATIA V5环境下，针对重复三维建模问题，应用参数化建模方法，建立零件的系列模型，构建了整线运动仿真的模型基础；在多装配体联动的整线仿真中，研究了装配关系对仿真机制的影响，提出了“One-Level”装配方法，有效提高了整线模拟效率。最后利用CATIA V5电子样机（DMU）技术对压机装模具过程和生产线冲压过程进行运动仿真、分析与优化，检查干涉碰撞和距离。结合应用实例，给出了方法应用的全过程。     

军事地下防护工程DEA评价

对决策单元进行有效性评价只有在具有“可比性”的同类规划方案中进行才有意义;对受评单元进行DEA评价,不仅要求“有效”,而且必须“可行”;军事地下防护工程由于自身的特点既要引入决策者的主观偏好又要恰当地用权值表示;当受评单元被评价为非DEA有效时,先寻找其受评单元与“最小凸包”的距离－－“效用差距”,再通过优化方法使其成为DEA有效。     

"金轮"号内燃动车组动车的研制

全面介绍了为兰州铁路局研制的“金轮”号内燃动车组动车的运用条件、性能特点、总体布置和主要部件的结构特点