Disruption management in production planning

We study the problem of recovering a production plan after a disruption, where the disruption may be caused by incidents such as power failure, market change, machine breakdown, supply shortage, worker no‐show, and others. The new recovery plan we seek after has to not only suit the changed environment brought about by the disruption, but also be close to the initial plan so as not to cause too much customer unsatisfaction or inconvenience for current‐stage and downstream operations. For the general‐cost case, we propose a dynamic programming method for the problem. For the convex‐cost case, a general problem which involves both cost and demand disruptions can be solved by considering the cost disruption first and then the demand disruption. We find that a pure demand disruption is easy to handle; and for a pure cost disruption, we propose a greedy method which is provably efficient. Our computational studies also reveal insights that will be helpful to managing disruptions in production planning. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

基于引擎成员的仿真调度问题

仿真引擎作为仿真系统的核心,是HLA仿真联邦中的特殊联邦成员。论述了基于实体、成员和引擎的层次式仿真调度概念结构,及其采用的基于时间序和事件序的仿真调度方案,将作战实体的时间推进和交战处理都归入仿真引擎,确保了全局时间统一性、实体同步性和交战事件的有序性,而且各种参量的设置灵活,便于控制。介绍了仿真引擎成员的设计与实现。该引擎成员在某指挥自动化作战效能仿真与评估系统中得以应用。     

高性能路由器中的分组非精确调度技术

随着网络带宽的不断提高,分组到达路由器的时间间隔不断缩短,对路由器处理分组的速度提出了新的要求。传统的分组调度算法,如WFQ,由于性能和可扩展性等问题,难以在高性能核心路由器中实现。为此,提出了分组非精确调度技术,在不影响应用QoS的前提下对经典的调度算法进行修改,通过简化硬件设计提高调度器的服务能力。模拟分析表明,采用非精确调度技术的SLQF算法的延时特性与传统算法LQF基本一致。     

Transshipment through crossdocks with inventory and time windows

A major challenge in making supply meet demand is to coordinate transshipments across the supply chain to reduce costs and increase service levels in the face of demand fluctuations, short lead times, warehouse limitations, and transportation and inventory costs. In particular, transshipment through crossdocks, where just‐in‐time objectives prevail, requires precise scheduling between suppliers, crossdocks, and customers. In this work, we study the transshipment problem with supplier and customer time windows where flow is constrained by transportation schedules and warehouse capacities. Transportation is provided by fixed or flexible schedules and lot‐sizing is dealt with through multiple shipments. We develop polynomial‐time algorithms or, otherwise, provide the complexity of the problems studied. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005     

On the asymptotic optimality of algorithms for the flow shop problem with release dates

We consider the nonpermutation flow shop problem with release dates, with the objective of minimizing the sum of the weighted completion times on the final machine. Since the problem is NP‐hard, we focus on the analysis of the performance of several approximation algorithms, all of which are related to the classical Weighted Shortest Processing Time Among Available Jobs heuristic. In particular, we perform a probabilistic analysis and prove that two online heuristics and one offline heuristic are asymptotically optimal. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

基于DCSP的编队武器兼容性约束协调

编队武器兼容性约束协调,是一个典型的求解分布式约束满足问题的过程。针对这一特点,建立了编队武器兼容性约束满足问题模型,提出了一种基于异步回溯的分布式约束满足算法。该算法运用异步回溯获得一个初始可行解,然后以作战效能最优为原则增添新的方案,并进行约束一致性检查,最终得到满意的编队武器运用方案。仿真验证了算法的可行性。     

基于多智能体的反导传感器任务规划算法

首先探讨了反导作战中各类传感器资源的构成特点和功能划分,然后基于多智能体multy-agent system(MAS)的分布式人工智能技术提出了适应反导作战需求的传感器任务规划体系架构,既而深入分析了体系架构中各类agent的主要功能,最后给出了一个实体层传感器的任务规划流程和算法实例,为构建高效率、智能化的反导作战多传感器任务规划技术提供了一种有效的研究方法。     

基于PCB技术的延时线设计方法

为了设计大功率低损耗的延时线,提出了用多股窄印制线并行绕制替代单股印制线绕制、在某些特定位置将并绕的多股印制线交叉换位的多层PCB螺旋电感的设计方法,并用该电感和电容模拟电缆的分布参数电感和电容制作延时线。通过多股并绕交叉换位的方式可以增加电感的有效截面积,减小电感的涡流损耗,有效提高电感的品质因数。测试结果表明:该螺旋电感的品质因数在短波频段内有较大提高。利用该螺旋电感制作的200ns延时线在通1A电流50 W功率时,延时性能好、驻波比小、衰减量小,满足大功率低损耗的要求。     

多专业批量维修任务调度方法研究

通过对不同专业设置方式下的维修任务调度问题进行分析,以最小化批量维修任务的维修时间为目标,将考虑专业维修顺序的批量维修任务调度问题分成两步进行求解,首先,建立了批量维修任务在专业领域内的调度及优化模型;其次,提出了基于NEH的批量维修任务排序方法．最后,通过实例对模型和方法的正确性和可行性进行了说明和验证,实例结果表明,该方法更贴近于实际,实现了快速、有效地解决维修任务调度问题,     

一种考虑权重的多专业流水式批量维修任务调度模型

针对维修专业不同的设置模式和运行模式,对多专业流水式批量维修任务调度问题进行了分析和建模,在考虑任务权重的基础上将该问题分成两步求解。首先,建立了初始专业领域内批量维修任务调度及优化模型;其次,建立了考虑任务权重的多专业流水式批量维修任务调度模型。实例验证表明：该方法更贴近于实际,可快速、有效地解决批量维修任务调度问题。