Testing the accuracy of employee-reported data: An inexpensive alternative approach to traditional methods

Although Information Technology (IT) solutions improve the collection and validation of operational data, Operations Managers must often rely on self-reported data from workers to make decisions. The problem with this data is that they are subject to intentional manipulation, thus reducing their suitability for decision-making. A method of identifying manipulated data, digital analysis, addresses this problem at low cost. In this paper, we demonstrate how one uses this method in real-world companies to validate self-reported data from line workers. The results of our study suggest that digital analysis estimates the accuracy of employee reported data in operations management, within limited contexts. These findings lead to improved operating performance by providing a tool for practitioners to exclude inaccurate information.     

全要素生产率和产业结构对能源利用影响的实证分析

本文利用能源消耗模型进行实证分析,结果表明决定能源利用效率的关键因素和长期因素是全要素生产率,全要素生产率的不断提高导致了我国经济快速发展而单位GDP能源消耗不断降低的特殊现象.产业结构对能源消耗有显著的短期影响,当第一产业比例下降或第二产业比例上升时,能源消耗增加。市场化程度、对外开放程度对能源消耗的作用体现在全要素生产率中.2000年后能源消耗重新抬头并不否定全要素生产率的作用,而是缺乏节能意识的负面影响抵消并逆转了全要素生产率的正面作用.     

Theoretical assessment of the errors involved in ultrasonic location and sizing of molten weld pools

Ultrasonic transit times may be used to locate the interface between molten weld metal and parent plate as a weld is formed. These transit times will lead to errors in interpretation of the location of the weld interface if account is not taken of the variation of ultrasonic velocity with temperature. We assess the magnitude of these errors using a theoretical model based on the Green's function to obtain the temperature distribution at any time and then convert the temperatures into elastic constants through empirical fits to high temperature data. A ray tracing method and a semi-analytical approach are used to estimate the effects of the changes in elastic constants on the ray paths and transit times. From these theoretical predictions we conclude that the location errors incurred by assuming ultrasonic velocities appropriate to cold metal are less than 0.5 mm for a 3.5 mm radius weld in austenitic steel or in iron. Experimental values tend to be larger than this, possibly suggesting that the solid-liquid interface is not as perfect as in the theoretical model. Under all of the conditions investigated, predicted errors are smaller with compression waves than with shear waves.     

关于工业产品生产许可证管理的探讨

对工业产品生产许可证管理方面存在的一些问题进行了探讨。经分析认为,在做好实地核查及证后监管的前提下,生产许可证制度的关键在于宣贯和相关细节的明确上。     

生物柴油高压共轨喷雾特性的试验研究

应用高速摄影系统与高压共轨系统,在高压定容器内研究了生物柴油的喷雾特性,并与柴油进行了对比。结果表明,生物柴油油束形态比柴油细且长,喷雾贯穿距离比柴油大,喷雾锥角比柴油小;高的运动黏度与表面张力导致生物柴油雾化性能比柴油差。随着喷油压力的升高,生物柴油喷雾贯穿距离变长,喷雾锥角增大;随着背压的升高,生物柴油喷雾贯穿距离...     

基于云理论的我国光伏产业产能过剩评估研究

基于云理论的评价方法,构建指标体系,利用云重心理论求出各指标的云模型,计算与理想状态向量的加权偏离度,以此衡量我国光伏产业产能过剩程度.该评价理论提高了评价结果的准确性,评价结果与实际情况吻合,表明该评价指标与评价方法具有较强的可操作性和科学性,并就此对光伏产业产能过剩的治理,提出了政策建议.     

基于信息显著性差异的绿色产业评价指标筛选模型及实证

依据广义的绿色产业内涵,通过信息显著性差异与信息冗余分析定量筛选指标,建立了包括绿色生产指标层、绿色生态环境指标层、绿色消费方式指标层的大连市绿色产业评价指标体系。本文的创新与特色一是通过负载系数大小差异进行信息显著性分析,删除负载系数小、对综合评价结果影响弱的指标。克服了现有研究先进行相关分析剔除冗余指标,再利用负载系数大小差异筛选出反映信息显著性大的指标的弊端。事实上,指标间较高的相关性是计算负载系数的必要前提。因此,利用负载系数筛选指标前是不可进行指标的相关分析降低指标间的相关性的。二是通过结合专家知识经验辨析指标的实际含义,仅对反映信息可能重复的指标使用相关分析,剔除同指标层内相关系数较大的两个指标中反映指标层信息能力相对较弱的指标。克服了仅仅通过相关系数不能准确衡量指标间信息重复程度的弊端。研究结果表明,最终建立的指标体系通过25．68％的指标反映了97．09％的原始信息。通过与同类的指标体系进行对比,对大连市绿色产业评价指标体系的合理性做了进一步的分析。     

基于物元可拓法的轨道交通PPP项目风险评价研究

风险评价是风险控制的前提,风险控制对项目成功实施至关重要.文章通过文献查阅和专家访谈梳理了PPP(Public-Private-Partnership)项目风险,建立涵盖37条指标的轨道交通PPP项目风险指标体系,构建基于物元可拓法的风险评价模型,以呼和浩特轨道交通PPP项目为例,对其项目风险进行了评价,提供一种PPP项目风险事前事中评价的方法,给项目相关方的项目风险评价和管理提供参考.     

Aggregate production planning for process industries under oligopolistic competition

We consider a competitive version of the traditional aggregate production planning model with capacity constraints. In the general case, multiple products are produced by a few competing producers (oligopoly) with limited capacities. Production quantities, prices and consequently profits depend on production and allocation decisions of each producer. In addition, there is competition for the raw material whose supplies are limited, and where prices reflect these limitations. Such situations have recently occurred in several process industry settings including petro-refining, petrochemicals, basic chemicals, cement, fertilizers, pharmaceuticals, rubber, paper, food processing and metals. We use a successive “Bertrand–Cournot” framework to address this problem and to determine optimal production quantities, prices and profits at the producers and at the raw material supplier. Our analysis allows a new way to understand and evaluate the marginal value of additional capacity when there is competition for the market and raw materials.     

A Mixed Integer Formulation for Multiple-Route Transit Network Design

We consider the design of multiple transit lines in a network and present a mixed integer formulation for this multiple-route transit network design problem (MRTNDP). With the introduction of node labels, the formulation can exploit the route structure and hence attains efficiency in obtaining a cost minimizing transit network design. This revised version was published online in July 2006 with corrections to the Cover Date.