方向矩异源图像匹配算法

全天候高精度导航与制导需要可靠的可见光与红外、可见光与合成孔径雷达(Synthetic Apeture Radar,SAR)的异源图像匹配算法。提出了一种基于方向矩的异源图像匹配算法:利用像素层次设计异源不变特征,描述像素点与其邻域各方向相似程度,通过统计比较各像素的相似性测度,实现不同传感器图像间的可靠匹配。进行了批量图像匹配实验,在可见光与红外、可见光与SAR异源图像间取得了超过90%的匹配正确率。较传统异源匹配算法,该算法大大提高了匹配正确率,在导航与制导领域有广阔的应用前景。     

Scheduling stochastic jobs with asymmetric earliness and tardiness penalties

We consider a stochastic counterpart of the well-known earliness-tardiness scheduling problem with a common due date, in which n stochastic jobs are to be processed on a single machine. The processing times of the jobs are independent and normally distributed random variables with known means and known variances that are proportional to the means. The due dates of the jobs are random variables following a common probability distribution. The objective is to minimize the expectation of a weighted combination of the earliness penalty, the tardiness penalty, and the flow-time penalty. One of our main results is that an optimal sequence for the problem must be V-shaped with respect to the mean processing times. Other characterizations of the optimal solution are also established. Two algorithms are proposed, which can generate optimal or near-optimal solutions in pseudopolynomial time. The proposed algorithms are also extended to problems where processing times do not satisfy the assumption in the model above, and are evaluated when processing times follow different probability distributions, including general normal (without the proportional relation between variances and means), uniform, Laplace, and exponential. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44, 531–557, 1997.     

钢筋混凝土外粘钢板结构裂缝的有限元数值模拟

随着高技术武器的不断发展,防护工程正面临着前所未有的威胁和挑战,新型防护结构及材料已经成为研究的热点。针对这一实际背景,运用ANSYS大型有限元软件,采用数值模拟的方法对普通钢筋混凝土结构和外粘钢板混凝土结构在相同均布面荷载作用下的变形、钢筋应力以及结构裂缝的开展情况进行了比较。结果表明外粘钢板的钢筋混凝土结构能够大大增强结构的抗力,并且有效的抑制了裂缝的开展。     

轴对称静电场不等距多重网格法的研究

研究了不等距多重网格法,可用于区域形状任意和有内电极的实际电子光学系统轴对称电场的计算,特别是对于求解区域大、部分区域电场精度要求高的场合,较好地解决了计算精度与划分网格点数之间的矛盾,可广泛应用于分析设计静电聚焦像管的电子光学系统,以及摄像管电子枪的发射系统等.     

An exact branch‐and‐price algorithm for multitasking scheduling on unrelated parallel machines

We consider the multitasking scheduling problem on unrelated parallel machines to minimize the total weighted completion time. In this problem, each machine processes a set of jobs, while the processing of a selected job on a machine may be interrupted by other available jobs scheduled on the same machine but unfinished. To solve this problem, we propose an exact branch‐and‐price algorithm, where the master problem at each search node is solved by a novel column generation scheme, called in‐out column generation, to maintain the stability of the dual variables. We use a greedy heuristic to obtain a set of initial columns to start the in‐out column generation, and a hybrid strategy combining a genetic algorithm and an exact dynamic programming algorithm to solve the pricing subproblems approximately and exactly, respectively. Using randomly generated data, we conduct numerical studies to evaluate the performance of the proposed solution approach. We also examine the effects of multitasking on the scheduling outcomes, with which the decision maker can justify making investments to adopt or avoid multitasking.     

Social benefits of government investment in enterprises

A critical issue for many governments is boosting the adoption rates of products or technologies that enhance consumer surplus or total social welfare. Governments may, for example, pay subsidies to producers or to consumers to stimulate the manufacture or consumption of specific products, for example, energy-efficient appliances or more effective drugs. This research proposes a strategic government investment policy, namely, share acquisition, and demonstrates its effectiveness in reaching societal objectives. We consider a Cournot quantities-choice market comprised of homogeneous firms where the government intervenes to buy shares, and turning private firms into state-owned enterprises. We recognize that purchasing a single private firm is the optimal policy for the government to reach its societal objectives. Additionally, taking into consideration financial constraints, we find that the optimal stake increases with the budget. Compared with the optimal output-based subsidy policy, when the budget is low, the optimal government investment policy induces a higher consumer surplus. In addition, in differentiated Cournot competition, under which firms compete in selling substitutable products, we find that when the budget is sufficient, the optimal stake purchased first decreases and then increases according to the substitutability level among products.     

立方星陀螺/双星敏感器组合定姿方法

针对单星敏感器绕视轴方向旋转角测量精度相对较差的问题,提出了一种利用微机电系统陀螺和同时工作的双星敏感器的测量来获得精确的立方星姿态信息的方法。该方法基于平均双四元数的思想,基于乘性扩展卡尔曼滤波算法制定了集中式和分散式两种姿态确定方案。仿真分析结果表明,所提出的陀螺/双星敏感器姿态确定方法,在采用低成本、低精度的姿态敏感器以及传统滤波算法的情况下,仍能有效提高立方星的定姿性能,具有较高的精度和较快的收敛性。为立方星低成本、高精度姿态确定提供了一种可行的参考,并且具备一定的工程应用价值。     

基于数据挖掘的装备维修性定量分析与研究

为了充分挖掘装备故障维修数据中的有用信息和知识,更好地为维修性分析、设计提供服务,根据所收集的某舰船装备维修历史数据的特点,提出采用数据挖掘的方法对在役装备故障和维修信息进行维修性定量分析。通过对装备维修历史数据中的装备进行面向功能属性的分类研究,对故障现象进行聚类分析研究,可以得到各类簇装备故障模式的分布情况,通过进一步计算,可以得到在役装备的平均修复时间(MTTR)等维修性指标,从而为装备故障原因分析、保障特性的设计需求生成等工作提供有效的数据支撑。     

微小型飞行器姿态快速机动控制方法

针对某弹道导弹释放的微小型飞行器的姿态控制任务需求,提出一种基于Gauss伪谱法的姿态快速机动控制方法。建立精确的姿态控制模型,并考虑反作用飞轮的耦合力矩项;采用Gauss伪谱法获取最优姿态轨迹,设计准滑模跟踪控制器以跟踪该最优轨迹。数字仿真结果表明,Gauss伪谱法计算得到的轨迹是最优的,准滑模跟踪控制器能实现对最优轨迹的良好跟踪,且对干扰力矩有较好的抑制作用。     

计算潜艇空调热负荷的传递函数法

通过对圆筒壁的导热微分方程进行拉氏变换 ,提出以传递函数为基础的空调动态负荷计算方法 ,推导出圆筒壁热力系统的动态数学模型 .根据此模型得出的潜艇空调热负荷动态计算结果比采用静态负荷计算法更准确 .