燃气轮机仿真软件构造方法综述

从方法论的角度综述了燃气轮机仿真软件的研究现状,分析了过程式方法和过程式模块化方法的不足,阐明采用面向对象方法的必要性,并对未来的发展方向作了初步探讨.     

地炮营通信系统载波监听／碰撞检测仿真分析

给出某地炮营通信系统信息传输的CSMA／CD(Carrier Sense Multiple Acces／Collision Detection)排队论模型,提出了信道争用和碰撞的问题,用单机和网络仿真分析了载波监听条件下通信失效的概率,给出信道争用和碰撞的几个性能指标,并利用软件的方法,提供了减少碰撞的方案     

等概率抽样群体演化算法的隐含并行性

在等概率抽样群体的条件下,讨论了演化算法的隐合并行性,得到了算法每代隐含处理的模式长度不超过ls（0≤ls≤l）的不同模式期望数的精确表达,并估计了其上下界．     

一种RetinaNet与SE融合的航空取证目标检测算法

针对在开展航空侦察取证时缺乏自动化、智能化取证手段的情况,提出了一种基于Reti-naNet与SE融合的航空取证目标检测算法,解决目标尺度变化大、数据集中类别不均衡的问题,并通过SE (squeeze-excitations)模块引入注意力机制进一步改进性能.该改进算法中的特征金字塔网络FPN可有效应对目标尺寸变化较大...     

Benders' cuts guided large neighborhood search for the traveling umpire problem

This article introduces the use of Benders' cuts to guide a large neighborhood search to solve the traveling umpire problem, a sports scheduling problem inspired by the real‐life needs of the officials of a sports league. At each time slot, a greedy matching heuristic is used to construct a schedule. When an infeasibility is recognized first a single step backtracking is tried to resolve the infeasibility. If unsuccessful, Benders' cuts are generated to guide a large neighborhood search to ensure feasibility and to improve the solution. Realizing the inherent symmetry present in the problem, a large family of cuts are generated and their effectiveness is tested. The resulting approach is able to find better solutions to many instances of this problem. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

Polynomial‐time approximation scheme for concurrent open shop scheduling with a fixed number of machines to minimize the total weighted completion time

In this article, we consider the concurrent open shop scheduling problem to minimize the total weighted completion time. When the number of machines is arbitrary, the problem has been shown to be inapproximable within a factor of 4/3 ‐ ε for any ε > 0 if the unique games conjecture is true in the literature. We propose a polynomial time approximation scheme for the problem under the restriction that the number of machines is fixed. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

一种基于移动基站的无线传感器网络数据收集方法

针对传统的无线传感器网络数据收集协议大多受制于发生在基站周围的热点问题,提出了一种使用移动基站的数据收集方法.将数据收集问题转化为支配集构造和旅行商问题,并提出了一种分布式的支配集构建算法,结合旅行商问题的近似算法生成基站的移动路线.仿真结果表明,所提出的方法减少了通信消耗,且能使负载均衡地分布.     

Batch scheduling on a two‐machine jobshop with machine‐dependent setup times

The problem of minimum makespan on an m machine jobshop with unit execution time (UET) jobs (m ≥ 3) is known to be strongly NP‐hard even with no setup times. We focus in this article on the two‐machine case. We assume UET jobs and consider batching with batch availability and machine‐dependent setup times. We introduce an efficient \begin{align*}(O(\sqrt{n}))\end{align*} algorithm, where n is the number of jobs. We then introduce a heuristic for the multimachine case and demonstrate its efficiency for two interesting instances. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

A genetic algorithm with neighborhood search for the resource‐constrained project scheduling problem

The resource‐constrained project scheduling problem (RCPSP) consists of a set of non‐preemptive activities that follow precedence relationship and consume resources. Under the limited amount of the resources, the objective of RCPSP is to find a schedule of the activities to minimize the project makespan. This article presents a new genetic algorithm (GA) by incorporating a local search strategy in GA operators. The local search strategy improves the efficiency of searching the solution space while keeping the randomness of the GA approach. Extensive numerical experiments show that the proposed GA with neighborhood search works well regarding solution quality and computational time compared with existing algorithms in the RCPSP literature, especially for the instances with a large number of activities. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

Periodic review inventory management with contingent use of two freight modes with fixed costs

We study a stochastic inventory model of a firm that periodically orders a product from a make‐to‐order manufacturer. Orders can be shipped by a combination of two freight modes that differ in lead‐times and costs, although orders are not allowed to cross. Placing an order as well as each use of each freight mode has a fixed and a quantity proportional cost. The decision of how to allocate units between the two freight modes utilizes information about demand during the completion of manufacturing. We derive the optimal freight mode allocation policy, and show that the optimal policy for placing orders is not an (s,S) policy in general. We provide tight bounds for the optimal policy that can be calculated by solving single period problems. Our analysis enables insights into the structure of the optimal policy specifying the conditions under which it simplifies to an (s,S) policy. We characterize the best (s,S) policy for our model, and through extensive numerical investigation show that its performance is comparable with the optimal policy in most cases. Our numerical study also sheds light on the benefits of the dual freight model over the single freight models. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011