Hierarchical composition heuristic for asymmetric sequence dependent single machine scheduling problems

We present the Hierarchical Composition (HICOM) heuristic procedure for single machine scheduling with sequence dependent setups that minimizes the total setup time. The heuristic is a two-stage procedure that takes advantage of the natural product groupings, and can be used in a group technology environment. Computational results show that HICOM requires negligible solution time for all cases tested with various sizes. More importantly, when benchmarked against the general purpose solver CPLEX, HICOM shows advantages in both CPU time and solution quality for large size problems. Thus, HICOM is highly valuable in practice when quick and good solutions are preferred in scheduling dynamics under the just-in-time lean manufacturing environment. Furthermore, when commercial software is not available, as often is the case for small to medium manufacturers, HICOM becomes a viable option because it is easy to understand and implement.     

A formal set of algorithms for project scheduling with critical path scheduling/material requirements planning

A hybrid model combining the critical path method (CPM) with material requirements planning (MRP) has been suggested (Aquilano) as a more robust method for scheduling projects and resources. The primary advantage of this technique is that resource acquisition lead times as well as inventory records are integrated into the process of computing the project schedule. This paper presents a set of formal CPM/MRP algorithms that may be used to compute the early and late start schedules as well as the critical sequence. A number of modifications have been incorporated into the CPM/MRP technique to improve the viability of CPM/MRP as a tool for application to actual project scheduling problems. A simple example project is used to demonstrate the CPM/MRP model.The CPM/MRP technique is designed to overcome a basic shortcoming of previously suggested project scheduling methodologies. CPM was initially designed to schedule projects subject to technological constraints only. Later, additional techniques were introduced to consider constraints upon various aspects of resource availability (Davis). None of the suggested techniques attempted to integrate resource acquisition lead time with the generation of requirements for resources. Obviously such a technique would require the integration of inventory records into the scheduling technique.The combination of CPM and MRP provides a possible vehicle for overcoming this drawback in CPM. Both CPM and MRP are linear models that generate schedules based upon precedence relationships. An integrated approach is useful since activities could be scheduled subject to information about the inventory position. An activity may be scheduled as soon as all resources are on hand. It is only delayed by those resources which must be acquired and activities which proceed it in the project network.CPM/MRP also shows promise as an aid to constrained resource scheduling since computations regarding resource availability are an integrated part of the technique. The effect of resource allocation decisions is immediately evident in the MRP-type time phased records.Results of the tests run on short projects of up to 300 activities and resources have shown that the program does work satisfactorily. Execution time for a 300 item network tested was approximately ten seconds on a CYBER 175.     

商业银行中间业务的现状、问题与对策

本文运用描述性统计方法,对10家上市银行中间业务收入的现状与问题进行了比较分析。研究表明,我国商业银行的中间业务发展较快,对业绩的贡献越来越大,但存在的问题也较为突出,如中间业务收入占比偏低、增速放缓、金融创新不足及业务同质化严重等。最后,文章提出了加大创新力度,注重差异化战略等相应的对策建议。     

UMP unbiased tests for multiparameter testing problems with restricted alternatives

Applications of the standard theory of UMP unbiased tests depends on conditions which in general are difficult to verify. In the present paper, however, we suggest more simple rules for applying this theory for regular exponential families of distributions. This approach leads to UMP unbiased tests for various multiparameter testing problems with restricted alternatives, and is shown to give justification for conditional tests for testing symmetry, diagonals-parameter symmetry and independence in two-way contingency tables. The derived tests are shown to possess attractive small sample properties. Received: June 1998     

无实际接地点的直流接地现象分析

本文介绍了一起蹊跷的直流接地现象,并结合工作经验探讨接地原因,旨在通过实践探索丰富继电保护人员的现场经验,从而规避直流接地风险,提高电网运行的安全系数。     

Bi-objective decision support system for routing and scheduling of hazardous materials

This paper presents a Pareto-based bi-objective optimization of hazardous materials vehicle routing and scheduling problem with time windows and shows its application to a realistic hazardous material logistics instance. A meta-heuristic solution algorithm is also proposed, which returns a set of routing solutions that approximate the frontier of the Pareto optimal solutions based on total scheduled travel time and total risk of whole transportation process. It works in a single-step fashion simultaneously constructing the vehicle route and selecting the optimal paths connecting the routed locations from a set of non-dominated paths obtained in terms of travel time and risk value.     

A note on strategies for bandit problems with infinitely many arms

A bandit problem consisting of a sequence of n choices (n) from a number of infinitely many Bernoulli arms is considered. The parameters of Bernoulli arms are independent and identically distributed random variables from a common distribution F on the interval [0,1] and F is continuous with F(0)=0 and F(1)=1. The goal is to investigate the asymptotic expected failure rates of k-failure strategies, and obtain a lower bound for the expected failure proportion over all strategies presented in Berry et al. (1997). We show that the asymptotic expected failure rates of k-failure strategies when 0<b1 and a lower bound can be evaluated if the limit of the ratio F(1)–F(t) versus (1–t)^b exists as t1^– for some b>0.     

基于组合赋权的理想解法及其应用

分析了主观赋权法和客观赋权法确定指标权重的优缺点,并针对单一赋权的缺点,将主观赋权法和客观赋权法进行有机的结合,从而合成了一种组合的指标权重确定方法,并对组合赋权的结果进行事前和事后检验,保证了权数的精确度.     

我国物流发展中存在的问题及建议

分析了我国物流发展中存在的主要问题，并针对我国的物流的发展提出了若干建议。     

A ‘funnel’ turnpike theorem for optimal growth problems with discounting

A turnpike theorem for the optimal control problem with discounting is given. The optimal trajectory is shown to lie in an exponentially bounded region of the optimal steady-state. This region, referred to as a funnel, is determined by the discount rate of the problem. The funnel theorem reduces to the classical turnpike theorem when the discount rate is zero.     

overview of OR techniques for airline revenue management

With the increasing interest in decision support systems and the continuous advance of computer science, revenue management is a discipline which has received a great deal of interest in recent years. Although revenue management has seen many new applications throughout the years, the main focus of research continues to be the airline industry. Ever since LITTLEWOOD (1972) first proposed a solution method for the airline revenue management problem, a variety of solution methods have been introduced. In this paper we give an overview of the solution methods presented throughout the literature.     

Using dynamic programming with adaptive grid scheme for optimal control problems in economics

The study of the solutions of dynamic models with optimizing agents has often been limited by a lack of available analytical techniques to explicitly find the global solution paths. On the other hand, the application of numerical techniques such as dynamic programming to find the solution in interesting regions of the state was restricted by the use of fixed grid size techniques. Following Grüne (Numer. Math. 75 (3) (1997) 319; University of Bayreuth, submitted, 2003), in this paper an adaptive grid scheme is used for finding the global solutions of discrete time Hamilton–Jacobi–Bellman equations. Local error estimates are established and an adapting iteration for the discretization of the state space is developed. The advantage of the use of adaptive grid scheme is demonstrated by computing the solutions of one- and two-dimensional economic models which exhibit steep curvature, complicated dynamics due to multiple equilibria, thresholds (Skiba sets) separating domains of attraction and periodic solutions. We consider deterministic and stochastic model variants. The studied examples are from economic growth, investment theory, environmental and resource economics.     

Optimal deterministic contracting mechanisms for principal-agent problems with moral hazard and adverse selection

For the principal-agent problem with moral hazard and adverse selection we establish that within the collection of all measurable, deterministic contracting mechanisms satisfying the individual rationality and incentive compatibility constraints there exists one that is optimal for a risk averse principal contracting with a risk averse agent. In addition to demonstrating existence, one of the main contributions of the paper is to show that, in general, centralized contracting implemented via a contracting mechanism is equivalent to delegated contracting implemented via a contract menu. Thus, contracting can always be delegated to the agent without gain or loss to the principal. Based on this result, the existence of an optimal contracting mechanism for the principal-agent problem is established by showing that there exists an optimal contract menu for the equivalent delegated contracting problem. Received: 7 October 1994 / Accepted: 14 January 1997     

Performance improvement in new product development with effective tools and techniques adoption for high-tech industries

Utilization of appropriate tools and techniques in the process of new product development (NPD) can assist firms to achieve better performances in launching new products. However, in practice, many useful tools and techniques are not utilized effectively. This study undertakes an in-depth empirical investigation of the appropriate tools or techniques that can be used at each stage of the NPD process. The study also analyzes the impact of individual tools or techniques both on overall NPD performance and on individual performance indicators within the process. The study finds that several NPD tools and techniques (for example, DOE, FMEA/DFMEA, and supplier involvement) have a significant effect on the overall performance of NPD and on a number of performance indicators, but that their utilization is not especially high. In addition, the study finds that DFX, conjoint analysis, and concept test, which also have a significant effect on NPD performance, are relatively neglected by the firms. The study provides valuable guidance to firms in using such tools and techniques more appropriately and effectively.     

Development of spatial ability extra tasks (SAET): problem solving with spatial intelligence

Quality & Quantity - Spatial ability contributes to performance in science, technology, engineering and mathematics (STEM). Spatial skills and creativity are required for engineering studies....     

基于等级划分的物流综合水平评价指标体系的构建

物流综合水平评价指标体系的构建要遵循一定的原则,同时要与具体的实际需求相结合.因此在框架的构建时既要考虑到评价指标体系具有的评价与控制双重功能和战略导向性,又要结合物流节点等级划分的实际;在指标的选掸上不但要综合物流业内外部影响因素,还要将显示性指标与解释性指标相结合,更要考虑到物流的供给和需求能力.     

基于等级划分的物流综合水平评价指标体系的构建

物流综合水平评价指标体系的构建要遵循一定的原则,同时要与具体的实际需求相结合。因此在框架的构建时既要考虑到评价指标体系具有的评价与控制双重功能和战略导向性,又要结合物流节点等级划分的实际;在指标的选择上不但要综合物流业内外部影响因素,还要将显示性指标与解释性指标相结合,更要考虑到物流的供给和需求能力。     

Short-term scheduling of crude oil operations in refinery with high-fusion-point oil and two transportation pipelines

In some refineries, storage tanks are located at two different sites, one for low-fusion-point crude oil and the other for high one. Two pipelines are used to transport different oil types. Due to the constraints resulting from the high-fusion-point oil transportation, it is challenging to schedule such a system. This work studies the scheduling problem from a control-theoretic perspective. It proposes to use a hybrid Petri net method to model the system. It then finds the schedulability conditions by analysing the dynamic behaviour of the net model. Next, it proposes an efficient scheduling method to minimize the cost of high-fusion-point oil transportation. Finally, it gives a complex industrial case study to show its application.     

The German federal employment program for regions with special employment problems: An evaluation

A special labor-market program to support regions with high unemployment was introduced in the Federal Republic of Germany in the summer of 1979. The program is evaluated through analyses of the determinants of the take-up rate and estimates of the impact on the unemployment rate using Box-Jenkins analysis. Evaluation of the program indicates some success with respect to training and public works creation, but also some serious shortcomings in design and implementation.     

Exact linear rank tests for two‐sample equivalence problems with continuous data

The present paper introduces a methodology for the semiparametric or non‐parametric two‐sample equivalence problem when the effects are specified by statistical functionals. The mean relative risk functional of two populations is given by the average of the time‐dependent risk. This functional is a meaningful non‐parametric quantity, which is invariant under strictly monotone transformations of the data. In the case of proportional hazard models, the functional determines just the proportional hazard risk factor. It is shown that an equivalence test of the type of the two‐sample Savage rank test is appropriate for this functional. Under proportional hazards, this test can be carried out as an exact level α test. It also works quite well under other semiparametric models. Similar results are presented for a Wilcoxon rank‐sum test for equivalence based on the Mann–Whitney functional given by the relative treatment effect.