Reconfiguring the Supply Network Using Current Performance Data

Reconfiguration of the supply chain network from time to time is essential for businesses to retain their competitive edge. This paper presents a methodology for reconfiguration of an existing supply chain network. The methodology is characterized by two decision levels. In the first level, the current network performance is evaluated and efficient practices are identified. In the next level, a model that incorporates efficient practices is developed to reconfigure the network. This integrated methodology allows for decision maker (DM) input throughout the process. The methodology has been implemented and tested in the reconfiguration of an outbound petroleum supply chain network for CountryMark Cooperative, Inc. In this case study, Data Envelopment Analysis (DEA) is used to analyze current operations and an integer programming (IP) model that incorporates efficiency metrics is developed for selection of distribution facilities and allocation of resources to the facilities. Use of this methodology can lead to improved operations and reduced operating expenses.     

Learning by Objectives for Adaptive Shop-Floor Scheduling*

Effective production scheduling requires consideration of the dynamics and unpredictability of the manufacturing environment. An automated learning scheme, utilizing genetic search, is proposed for adaptive control in typical decentralized factory-floor decision making. A high-level knowledge representation for modeling production environments is developed, with facilities for genetic learning within this scheme. A multiagent framework is used, with individual agents being responsible for the dispatch decision making at different workstations. Learning is with respect to stated objectives, and given the diversity of scheduling goals, the efficacy of the designed learning scheme is judged through its response under different objectives. The behavior of the genetic learning scheme is analyzed and simulation studies help compare how learning under different objectives impacts certain aggregate measures of system performance.     

Staffing a Multiskilled Workforce with Varying Levels of Productivity: An Analysis of Cross-training Policies*

Service operations that utilize cross-trained employees face complex workforce staffing decisions that have important implications for both cost and productivity. These decisions are further complicated when cross-trained employees have different productivity levels in multiple work activity categories. A method for policy analysis in such environments can be beneficial in determining low-cost staffing plans with appropriate cross-training configurations. In this paper, we present an integer linear programming model for evaluating cross-training configurations at the policy level. The objective of the model is to minimize workforce staffing costs subject to the satisfaction of minimum labor requirements across a planning horizon of a single work shift. The model was used to evaluate eight cross-training structures (consisting of 36 unique cross-training configurations) across 512 labor requirement patterns. These structures, as well as the labor requirement patterns, were established based on data collected from maintenance operations at a large paper mill in the United States. The results indicate that asymmetric cross-training structures that permit chaining of employee skill classes across work activity categories are particularly useful.     

中国节节麦的细胞遗传学研究及有关问题探讨

应用染色体组分析法,对新疆节节麦、黄河流域节节麦、伊朗节节麦和中东节节麦的D染色体组进行了较系统的比较分析,结果表明:新疆节节麦与伊朗、中东两地节节麦在染色体组水平上无明显差异,其差异仅体现在染色体的细微结构组成上;臂内倒位是引起染色体结构组成上细微分化的主要原因。黄河流域节节麦与新疆节节麦的染色体组极为相近;其D组染色体无论在染色体组水平上,还是在染色体细微结构组成上均无差异。本文还就中国节节麦与中国特有六倍体普通小麦的起源演化,中国节节麦种质资源在现代小麦育种中的应用等问题进行了讨论。     

农业科技成果转化为现实生产力的对策

根据目前影响我国农业技术成果迅速转化为现实生产力的因素,提出了加速农业技术成果转化的对策。     

PES-C,(PP/Bis-T)PES的次级松驰与转变

描述了酚酞型聚芳醚砜(PES-C)的次级松驰和转变与其结构的关系.TBA和动态力学实验结果表明:PES-C及其共聚物(PP/Bis-T)PES分别在0～50℃和-100℃附近呈现出两个次级松驰峰;双酚T单元的引入导致了PES-C在0～50℃之间的次级松驰位置改变.证实了Cardo侧基的存在对-100℃的次级松驰有较大的贡献.     

由1971—2011年诺贝尔文学奖获奖情况反思中国文学

针对当前现状,以1971—2011年的诺贝尔文学奖四十年来的获奖情况为研究对象,从获奖作家所属的不同的国家分布、作家性别比例及和获奖作品风格与主旨这三个大的方面入手进行分析,探究诺贝尔文学奖的发展态势,概括和反思目前中国文学的发展状况,剖析中国作家莫言的获奖原因,由此提出对于中国作家要在诺贝尔文学奖中占有更多席位需要完善方面的建议和看法。     

Comparing two measures of creatinine clearance: an application of errors-in-variables and bootstrap techniques

Two indices of creatinine clearance (an index of kidney function) are compared on a group of cancer patients who underwent chemotherapy with a potentially nephrotoxic drug. The standard index, measured creatinine clearance MCC, is cumbersome to use, whereas the more convenient alternative, estimated creatinine clearance ECC, has not yet been conclusively evaluated on cancer patients. We conclude that under certain clinical conditions ECC and MCC are identically calibrated for males, but not for females, and we obtain estimated true and false positive rates for assessing the use of ECC instead of MCC as a diagnostic tool. We use a model that is formally equivalent to an errors-in-variables model with (unbalanced) repeated observations and correlated measurement errors. The bootstrap is used to obtain standard errors and confidence limits.     

The zero-inflated Poisson model and the decayed, missing and filled teeth index in dental epidemiology

For frequency counts, the situation of extra zeros often arises in biomedical applications. This is demonstrated with count data from a dental epidemiological study in Belo Horizonte (the Belo Horizonte caries prevention study) which evaluated various programmes for reducing caries. Extra zeros, however, violate the variance–mean relationship of the Poisson error structure. This extra-Poisson variation can easily be explained by a special mixture model, the zero-inflated Poisson (ZIP) model. On the basis of the ZIP model, a graphical device is presented which not only summarizes the mixing distribution but also provides visual information about the overall mean. This device can be exploited to evaluate and compare various groups. Ways are discussed to include covariates and to develop an extension of the conventional Poisson regression. Finally, a method to evaluate intervention effects on the basis of the ZIP regression model is described and applied to the data of the Belo Horizonte caries prevention study.