工作流协同系统性能评价研究

利用广义随机Petri网系统性能分析的优势,在组织间工作流模型基础上引入时间因素,并利用Petri网对局部工作流之间不同通信关系进行描述,最终构建了时间组织间工作流模型,为工作流协同系统性能评价问题提出了解决思路.     

面向角色的多agent 工作流模型研究

目前的工作流建模工具大多是面向活动、面向产品、面向目标或面向决策的,没有强调工作流 是多个角色主体协作的过程,工作流的绩效最终依赖员工及其角色的作用. 从角色及其合作的角 度,分析了面向角色的工作流模型及其表示方法,为工作流的管理提供新的思路. 在此基础上,研究 了角色、agent 和工作流的关系,给出了一种面向角色的工作流多agent 管理系统模型和原型.     

面向角色的多agent 工作流模型研究

目前的工作流建模工具大多是面向活动、面向产品、面向目标或面向决策的,没有强调工作流是多个角色主体协作的过程,工作流的绩效最终依赖员工及其角色的作用.从角色及其合作的角度,分析了面向角色的工作流模型及其表示方法,为工作流的管理提供新的思路.在此基础上,研究了角色、agent和工作流的关系,给出了一种面向角色的工作流多agent管理系统模型和原型.     

基于工作流的装备经费业务流程管理研究

为提高装备经费的管理效率和使用效益,提出将工作流技术应用到装备经费业务流程管理中。通过活动网络的建模方法对装备经费业务流程建模,使流程在工作流管理系统上运行,实现业务的自动流转。最后构建了基于工作流的装备经费管理系统集成框架,实现流程在各业务系统之间执行所需的信息交互。     

面向业务流程重组的过程分析与建模方法研究

为寻求全面支持BPR的过程建模方法,本文在工作流管理联盟(WfMC)所提供的参考模型基础上,提出了一种附带有过程语义字典的工作流扩展模型,并以这种模型为工具,分别对过程内部活动的相似性和过程之间的耦合性进行了分析,而且还探讨了基于这两种分析结果的过程再设计方法.     

跨组织工作流建模及分析研究述评

从组织间工作流的层面对跨组织工作流建模的已有研究进行分类、总结和评价.然后,从定性分析和定量分析2个角度综述了工作流分析的相关研究.最后,总结了该领域研究的管理实践意义,并针对现有研究存在的不足,探讨了未来的研究趋势和发展方向.     

基于角色的工作流研究

工作流管理系统是集成企业的信息、参与者和资源,实现过程自动化的CSCW系统.面对变化的经营环境,企业的业务过程呈现动态、不确定的特点.工作流管理系统能否有效处理这种动态性直接影响了其应用效果.传统工作流的定义以活动为组成要素,不易表达参与者的交互和动态行为.本文讨论了基于角色的动态工作流,给出了一种消息顺序图和ECA规则的复合表示方法.     

企业融资约束的定量方法及其评价

中外学者在研究融资约束过程中普遍面临的问题是,可否找到一个准确度量企业融资约束与否的指标,是否可以构造精准定量约束大小的指数,以及构造出的融资约束指数可运用到哪些研究中。笔者旨在梳理国内外学者在实证过程中建立的融资约束指数,对其计量方法做出归纳,并简要分析如何评价已建立的融资约束指数。     

复杂不确定环境下活动可拆分的项目资源鲁棒性调度优化

复杂不确定环境下,制定一个具有较强抗干扰能力的基准进度计划非常必要。本文研究了活动工期不确定环境下考虑活动可拆分的项目资源鲁棒性调度优化问题,旨在考虑活动可拆分,探究在活动优先关系约束、项目截止日期约束、活动拆分约束、资源流约束等条件下如何进行活动拆分决策并合理地安排各个项目活动/活动分段间的资源调配方案和时间缓冲添加策略,以制定鲁棒性最大化的基准进度计划。本文创新点如下：1)在项目资源鲁棒性调度优化问题中考虑活动可拆分,定义了资源流网络下活动自由时差的计算方法,提出了一种新的活动可拆分情形下进度计划鲁棒性的衡量方式,进而构建得到了考虑活动可拆分的项目资源鲁棒性调度优化模型;2)分析证明了问题模型的强NP-hard属性以及非线性属性,并在此基础上开发了一种内嵌资源调度安排的遗传算法进行问题求解;3)选取一个典型的实际案例对研究问题进行说明,直观展示了活动拆分执行对进度计划鲁棒性提升的重要价值,揭示了鲁棒性调度计划中资源调度方案的重要性,得到了活动拆分执行会增加项目内部资源转移次数的结论。     

考虑波次订单动态释放的B2C电商订单合并配送决策方法

本文针对动态释放、异质性强的B2C电商波次订单的物流配送决策难题,以提高车辆满载率、降低配送成本为目标,研究考虑波次订单动态释放的B2C电商订单城区物流合并配送问题。首先,将原动态问题建模为一阶马尔可夫决策过程以表达其多阶段时序序贯决策的特点;其次,基于状态转移具有的时序特征,提出一种基于时序预测的前向动态规划方法用于寻找最优策略,将时序预测信息融入到合并配送决策的模型中,并结合定性启发式规则与定量优化模型以兼顾方法的决策效率与优化能力;最后,基于标准算例下的数值实验和某B2C电商平台的实例分析,验证了所提方法的有效性和实用性。此研究可为B2C电商订单物流配送提供决策支持,同时对于状态转移具有时序特征的马尔可夫决策问题提供了求解的新思路。     

Some graph optimization problems with weights satisfying linear constraints

In this paper, we study several graph optimization problems in which the weights of vertices or edges are variables determined by several linear constraints, including maximum matching problem under linear constraints (max-MLC), minimum perfect matching problem under linear constraints (min-PMLC), shortest path problem under linear constraints (SPLC) and vertex cover problem under linear constraints (VCLC). The objective of these problems is to decide the weights that are feasible to the linear constraints, and find the optimal solutions of corresponding graph optimization problems among all feasible choices of weights. We find that these problems are NP-hard and are hard to be approximated in general. These findings suggest us to explore various special cases of them. In particular, we show that when the number of constraints is a fixed constant, all these problems are polynomially solvable. Moreover, if the total number of distinct weights is a fixed constant, then max-MLC, min-PMLC and SPLC are polynomially solvable, and VCLC has a 2-approximation algorithm. In addition, we propose approximation algorithms for various cases of max-MLC.

     

Iterative Converging Algorithms for Computing Bounds on Durations of Activities in Pert and Pert-Like Models

Since its invention in 1958, Program Evaluation and Review Technique (PERT) has been widely used during the planning, design, and implementation of projects. Pert models the activities of a project as a single source-single sink directed acyclic graph where nodes represent events (end or beginning of activities) and arcs activities. The maximum amount by which an activity can be delayed without delaying the overall project is called the slack. Critical tasks have zero slack whereas all noncritical tasks have positive slacks. Pert is a valuable tool in the management of large projects since it allows to compute the slack of each activity of the project. Such information may be crucial in avoiding cost overruns that would be caused by delays to critical activities and/or excessive delays to noncritical activities. What Pert fails to provide is how one should go about distributing remaining slack on noncritical activities while taking into consideration properties of the activities as well as precedence relationships among them, so as to have reasonable upper bounds on duration of all activities, critical or noncritical. In this paper we propose several algorithms for the distribution of slack on non-critical activities. We show that if one desires to distribute the remaining slack proportionally to the initially assigned activity durations then the problem is in P, and propose an algorithm of linear time complexity. However if one desires to use distribution functions other than the initial durations of activities, then the problem of slack distribution becomes NP-complete. Finding the maximal bounds corresponding to zero-slack solution at the sink requires iterative application of exponential algorithm. For that case we introduce an approximation algorithm of linear time complexity on each iteration. The algorithm iteratively increases bounds on durations of activities and converges to the zero-slack solution on all paths from the source node to the sink node in the Pert-like graph. The algorithms described in this paper were successfully applied to solving timing bounds problems in VLSI design.     

应用内点算法求解允许买空/卖空情况下的投资组合问题

本文着重讨论了允许买空卖空条件下的投资组合求解问题。由于在实际的经济活动中存在买空卖空的现象,本文讨论了这种情况下的最优化模型,并用内点算法结合Matlab编程,给出了问题的最优解。同时,对投资者对风险的偏好系数A进行了数值分析,可以得到最优的A值A^*,即当投资者对风险的偏好系数A=A^*时,投资者可以得到最大的投资效用。     

EDUCATION

This paper illustrates how multivariate spectral analysis can be used to analyze complex, dynamic, business systems. Important temporal aspects of multiple time series are captured in the frequency domain by the coherence, phase, and gain statistics. A computer simulation of a time domain model produces sample results which demonstrate how the timing relations between two series can be reversed when the effects common to both series are partialled out. Finally, an empirical multivariate analysis of beef prices is used to determine the timing relations among prices at different levels of the production-distribution system.     

Algorithms for the workflow satisfiability problem engineered for counting constraints

The workflow satisfiability problem (WSP) asks whether there exists an assignment of authorized users to the steps in a workflow specification that satisfies the constraints in the specification. The problem is NP-hard in general, but several subclasses of the problem are known to be fixed-parameter tractable (FPT) when parameterized by the number of steps in the specification. In this paper, we consider the WSP with user-independent counting constraints, a large class of constraints for which the WSP is known to be FPT. We describe an efficient implementation of an FPT algorithm for solving this subclass of the WSP and an experimental evaluation of this algorithm. The algorithm iteratively generates all equivalence classes of possible partial solutions until, whenever possible, it finds a complete solution to the problem. We also provide a reduction from a WSP instance to a pseudo-Boolean (PB) SAT instance. We apply this reduction to the instances used in our experiments and solve the resulting PB SAT problems using SAT4J, a PB SAT solver. We compare the performance of our algorithm with that of SAT4J and discuss which of the two approaches would be more effective in practice.     

A SYSTEMATIC STRATEGY FOR OPTIMIZING MANUFACTURING OPERATIONS

A manufacturing optimization strategy is developed and demonstrated, which combines an asset utilization model and a process optimization framework with multivariate statistical analysis in a systematic manner to focus and drive process improvement activities. Although this manufacturing strategy is broadly applicable, the approach is discussed with respect to a polymer sheet manufacturing operation. The asset utilization (AU) model demonstrates that efficient equipment utilization can be monitored quantitatively and improvement opportunities identified so that the greatest benefit to the operation can be obtained. The process optimization framework, comprised of three parallel activities and a designed experiment, establishes the process-product relationship. The overall strategy of predictive model development provided from the parallel activities comprising the optimization framework is to synthesize a model based on existing data, both qualitative and quantitative, using canonical discriminant analysis, to identify main effect variables affecting the principal efficiency constraints identified using AU, operator knowledge and order-of-magni-tude calculations are then employed to refine this model using designed experiments, where appropriate, to facilitate the development of a quantitative, proactive optimization strategy for eliminating the constraints. Most importantly, this overall strategy plays a significant role in demonstrating, and facilitating employee acceptance, that the manufacturing operation has evolved from an experienced-based process to one based on quantifiable science.     

带权重约束的DEA超效率评价模型及其应用研究

针对产学研协同创新项目的相对效率比较问题,数据包络分析（DEA）法是比较有效的数量分析方法。但DEA法所构建的优化模型中,由于约束条件没有充分考虑评价指标体系内部指标之间客观存在的内在权重大小信息,从而导致模型过分强调了评价单元的投入产出特征差异,甚至出现了原本非常重要的指标其权重却为0的不合理现象。本文提出DEMATEL法和数据包络分析法有机结合的思想,将运用DEMATEL法获得的指标之间内在的权重大小信息,纳入DEA法非阿基米德无穷小量ε限制的CCR模型及其超效率模型的约束条件,创新模型的可行域,构建了权重约束型ε-CCR模型和超效率ε-CCR模型。并以美国2014-2015年度国家科学基金会产学研合作研究中心发布的年度报告数据,对美国71个以高校为主导的产学研协同创新中心的相对效率进行了实证分析。实证结果显示,权重约束型超效率ε-CCR模型比没有权重约束的超效率ε-CCR模型更有效,不仅能对多个评价单位进行全排序,而且能克服无权重约束的超效率ε-CCR模型存在的评价结果不合理现象。这些结果有助于进一步推动DEA法的理论创新和应用推广,并能为多投入多产出项目的决策提供新的方法,使实际问题决策更合理更科学。     

The maximum flow problem with disjunctive constraints

We study the maximum flow problem subject to binary disjunctive constraints in a directed graph: A negative disjunctive constraint states that a certain pair of arcs in a digraph cannot be simultaneously used for sending flow in a feasible solution. In contrast to this, positive disjunctive constraints force that for certain pairs of arcs at least one arc has to carry flow in a feasible solution. It is convenient to represent the negative disjunctive constraints in terms of a so-called conflict graph whose vertices correspond to the arcs of the underlying graph, and whose edges encode the constraints. Analogously we represent the positive disjunctive constraints by a so-called forcing graph. For conflict graphs we prove that the maximum flow problem is strongly $\mathcal{NP}$ -hard, even if the conflict graph consists only of unconnected edges. This result still holds if the network consists only of disjoint paths of length three. For forcing graphs we also provide a sharp line between polynomially solvable and strongly $\mathcal{NP}$ -hard instances for the case where the flow values are required to be integral. Moreover, our hardness results imply that no polynomial time approximation algorithm can exist for both problems. In contrast to this we show that the maximum flow problem with a forcing graph can be solved efficiently if fractional flow values are allowed.