根据教员工作特点科学管理教员队伍

通过科学分析教员队伍的工作特点,探索教员队伍管理的规律,结合本系实际,提出采取"4种形象"教育,以教育为主,以调动积极性为主,以发挥教员主观能动性为主,建设一直政治合格、思想稳定、年龄和知识结构合理、具有较高教学和科研能力的教员队伍的改革措施.     

运动船舶磁性船体产生的感应电场

为了研究运动船舶磁性船体产生的感应电场,以库伦定律和毕奥-沙伐定律等电磁场基本理论为基础,对磁偶极子运动产生的感应电场进行了建模,通过实验证明了分析方法的正确性,解决了以往模型适用范围窄、准确性差的问题;并以磁偶极子感应电场模型为基础,得到了磁性船体的感应电场模型,利用实船的磁场数据进行了实例计算,得出船舶附近感应电场可达1m V/m,达到了可探测水平。     

Integrated scheduling of loading and transportation with tractors and semitrailers separated

Motivated by some practical applications, we study a new integrated loading and transportation scheduling problem. Given a set of jobs, a single crane is available to load jobs, one by one, onto semitrailers with a given capacity. Loaded semitrailers are assigned to tractors for transportation tasks. Subject to limited resources (crane, semitrailers, and tractors), the problem is to determine (1) an assignment of jobs to semitrailers for loading tasks, (2) a sequence for the crane to load jobs onto semitrailers, (3) an assignment of loaded semitrailers to tractors for transportation tasks, and (4) a transportation schedule of assigned tractors such that the completion time of the last transportation task is minimized. We first formulate the problem as a mixed integer linear programming model (MILPM) and prove that the problem is strongly NP‐hard. Then, optimality properties are provided which are useful in establishing an improved MILPM and designing solution algorithms. We develop a constructive heuristic, two LP‐based heuristics, and a recovering beam search heuristic to solve this problem. An improved procedure for solutions by heuristics is also presented. Furthermore, two branch‐and‐bound (B&B) algorithms with two different lower bounds are developed to solve the problem to optimality. Finally, computational experiments using both real data and randomly generated data demonstrate that our heuristics are highly efficient and effective. In terms of computational time and the number of instances solved to optimality in a time limit, the B&B algorithms are better than solving the MILPM. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 416–433, 2015     

基于改进Morison公式的海上漂浮软管波浪载荷计算

针对海上漂浮软管波浪载荷计算,分析了软管在海上的形态和受力特点,建立了海上漂浮软管力学分析模型,指出直接运用现有Morison方程计算漂浮软管波浪载荷存在的不足,并根据基本原理提出了改进Morison方程。对海上软质管线处于一定海况,分别运用改进Morison方程与现有Morison方程计算海上波浪载荷,并运用ANSYS软件建立软管模型,结果表明现有Morison方程不适用于计算海上漂浮软管波浪载荷,载荷计算结果偏高约15%,从而验证了改进Morison方程的精确性,有利于准确分析波浪载荷对海上漂浮软管的作用情况。     

一种新的基于特征值分解的双站无源定位算法

在自卫式噪声干扰的条件下,地面制导雷达将无法得到目标的斜距信息,无法实现对目标的定位,此时只有采用雷达组网方式,利用2个或多个雷达站的测角信息来对空间目标进行定位。提出一种基于特征值分解的新的定位跟踪算法,该算法具有计算简单、清晰,运算量小的优点,仿真也表明该算法有较好的精度。     

视频监控系统中的动目标检测新方法

在分析了现有算法在复杂背景下所存在的不足的基础上,提出了一种适用于视频监控系统的基于视频序列像素时空相关性检测的动目标检测方法.该方法首先用每一帧中像素的空间相关性检测出目标,再用序列图像中目标的时间相关性检验目标的真实性,从而最终确定是否有运动目标.试验表明,该方法能很好地检测出运动目标,并具有较强的抗干扰能力.     

Optimal inventory control policy for periodic‐review inventory systems with inventory‐level‐dependent demand

We consider a setting in which inventory plays both promotional and service roles; that is, higher inventories not only improve service levels but also stimulate demand by serving as a promotional tool (e.g., as the result of advertising effect by the enhanced product visibility). Specifically, we study the periodic‐review inventory systems in which the demand in each period is uncertain but increases with the inventory level. We investigate the multiperiod model with normal and expediting orders in each period, that is, any shortage will be met through emergency replenishment. Such a model takes the lost sales model as a special case. For the cases without and with fixed order costs, the optimal inventory replenishment policy is shown to be of the base‐stock type and of the (s,S) type, respectively. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

Models and algorithms for shuffling problems in steel plants

In this article, we study item shuffling (IS) problems arising in the logistics system of steel production. An IS problem here is to optimize shuffling operations needed in retrieving a sequence of steel items from a warehouse served by a crane. There are two types of such problems, plate shuffling problems (PSP) and coil shuffling problems (CSP), considering the item shapes. The PSP is modeled as a container storage location assignment problem. For CSP, a novel linear integer programming model is formulated considering the practical stacking and shuffling features. Several valid inequalities are constructed to accelerate the solving of the models. Some properties of optimal solutions of PSP and CSP are also derived. Because of the strong NP‐hardness of the problems, we consider some special cases of them and propose polynomial time algorithms to obtain optimal solutions for these cases. A greedy heuristic is proposed to solve the general problems and its worst‐case performances on both PSP and CSP are analyzed. A tabu search (TS) method with a tabu list of variable length is proposed to further improve the heuristic solutions. Without considering the crane traveling distance, we then construct a rolling variable horizon heuristic for the problems. Numerical experiments show that the proposed heuristic algorithms and the TS method are effective. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

多核环境下负载均衡的并行离散事件全局调度机制

分析了多核环境下传统的离散事件时间弯曲并行系统的性能,针对其事件调度开销小和负载均衡能力强难以兼得的问题,提出了一种基于分布式队列的全局调度机制,设计了相应的数据结构和调度算法,大大减少了锁开销.通过大量实验对多核环境下几种典型离散事件系统并行策略的性能分析表明,本文提出的全局调度策略不仅事件调度开销小,而且回滚率大大降低,有效克服了传统策略回滚量较大或难以实现动态负载平衡的情况,并具备良好的可扩展性.     

MEFP战斗部结构的正交优化设计

以多爆炸成型弹丸(MEFP)为计算模型,应用显式有限元程序LS-DYNA,分析了药型罩间距、锥角、壁厚、装药高度和装药直径5种因素对MEFP发散角的影响规律。结果表明:随着药型罩间距、壁厚和装药直径的增加以及药型罩锥角、装药高度的减小,MEFP的发散角在减小。在此基础上以MEFP发散角为命中和毁伤概率指标,应用正交优化方法针对5种结构因素对MEFP发散角的影响主次关系进行了分析研究。结果表明药型罩壁厚是MEFP战斗部命中和毁伤概率的主要影响因素,并得到了5种结构因素各水平的最优组合。