基于凸优化理论的三维微分对策制导规律求解

针对三维微分对策制导律(DGL)求解问题,引入凸优化理论,将DGL求解归结到Hamilton系统的求解,设计了DGL求解算法,通过对代价函数梯度特征的凸分析,推导出对策系统鞍点存在的充要条件和求解方法,解决了以往通过对微分对策模型简化求解导致的模型不能客观反映作战过程的问题.     

零彗差自由点条件下的失调光学系统波像差特性分析

基于矢量像差理论,对反射式光学系统的一类特殊失调状态——满足零彗差自由点条件展开研究,分析了该特殊失调下三阶彗差和三阶像散的全视场波像差特性,建立了三阶像散双节点位置的解析计算公式,研究发现该类失调不会引入三阶彗差,并且会导致三阶像散的一个节点位于中心视场附近,揭示了当前传统装调方法中仅采用轴上彗差为零作为系统完善装调的弊端,并基于像差特性分析提出了一种仅根据轴上视场引入定量失调误差前后的像差变化来评估系统完善装调的方法。利用CODE V(Version 10.2)对两反式光学系统进行了仿真分析,结果表明文中建立的模型和方法可定量分析三阶像散双节点的位置及该类失调对系统波像差的影响规律,并验证了所提出系统完善装调方法的有效性。     

杂波环境下机动目标跟踪算法研究

杂波环境下的机动目标跟踪问题具有非线性、非高斯、不完全观测的特点,其难点在于观测值与目标的对应关系及每一时刻的运动模式均呈现高度不确定性。文中将多模型理论和辅助粒子滤波算法相结合,提出了一种新的杂波环境下机动目标跟踪算法——多模型辅助粒子滤波算法(MMAPF)。仿真结果表明,该算法与传统的交互多模型——扩展卡尔曼滤波算法、辅助粒子滤波算法相比,在相同的情况下,具有更高的滤波精度和较好总体性能。     

基于D-S推理的灰关联通信电台识别研究

为了解决通信电台识别问题,在灰关联识别的过程中,引入D-S证据理论,通过对信号的积累和对信任度的重新分配,对识别结果进行了有效的融合,提高了辐射源的正确识别率。仿真结果表明了该方法的可行性和有效性。     

Discrete search allocation game with false contacts

This paper deals with a two‐person zero‐sum game called a search allocation game, where a searcher and a target participate, taking account of false contacts. The searcher distributes his search effort in a search space in order to detect the target. On the other hand, the target moves to avoid the searcher. As a payoff of the game, we take the cumulative amount of search effort weighted by the target distribution, which can be derived as an approximation of the detection probability of the target. The searcher's strategy is a plan of distributing search effort and the target's is a movement represented by a path or transition probability across the search space. In the search, there are false contacts caused by environmental noises, signal processing noises, or real objects resembling true targets. If they happen, the searcher must take some time for their investigation, which interrupts the search for a while. There have been few researches dealing with search games with false contacts. In this paper, we formulate the game into a mathematical programming problem to obtain its equilibrium point. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

Inventory control and periodic price discounting campaigns

This paper develops an inventory model that determines replenishment strategies for buyers facing situations in which sellers offer price‐discounting campaigns at random times as a way to drive sales or clear excess inventory. Specifically, the model deals with the inventory of a single item that is maintained to meet a constant demand over time. The item can be purchased at two different prices denoted high and low. We assume that the low price goes into effect at random points in time following an exponential distribution and lasts for a random length of time following another exponential distribution. We highlight a replenishment strategy that will lead to the lowest inventory holding and ordering costs possible. This strategy is to replenish inventory only when current levels are below a certain threshold when the low price is offered and the replenishment is to a higher order‐up‐to level than the one currently in use when inventory depletes to zero and the price is high. Our analysis provides new insight into the behavior of the optimal replenishment strategy in response to changes in the ratio of purchase prices together with changes in the ratio of the duration of a low‐price period to that of a high‐price period. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007.     

PELE正侵穿金属薄靶轴向剩余速度近似计算与分析

运用冲击波理论,对横向效应增强型弹丸(Penetration with Enhanced Lateral Efficiency,PELE)侵穿金属靶板的机理进行了分析,将PELE侵彻过程中能量损失分为外壳和内芯撞击靶板区域环形塞块获得的能量,冲击波影响范围内外壳和内芯增加的内能,外壳前端外沿和内沿对靶板冲塞剪切耗能等,给出了确定这些能量的计算方法;并依据能量守恒原理,给出了PELE正撞金属薄靶板靶后剩余速度的近似计算公式。公式计算结果与多种条件下实验结果均吻合较好。分析计算所得各能量损失结果表明,弹体内芯材料的变化对弹体侵彻能力的影响较小;侵彻中靶板塞块获得的能量在弹体侵彻动能损失中比重最大;外壳前端内沿对靶板的剪切能耗对弹体动能损失的影响可以忽略。     

黏弹性基底上阻尼碳纳米管的动力学特性

采用欧拉梁模型建立了有阻尼碳纳米管在黏弹性基底上的动力学问题分析模型。通过引入非局部理论、广义Maxwell黏弹性模型、速度相依的外阻尼模型及黏弹性基底模型推导出碳纳米管动力学分析的欧拉梁振动控制方程。在Kelvin-Voigt黏弹性模型基础上,分别给出无基底和全基底支撑时碳纳米管固有频率的一般解析表达式,并分析讨论全基底时的多种典型情况。然后利用传递函数方法求解出一般边界条件下振动控制方程的封闭解。以某单壁碳纳米管为例,得到不同边界条件下该单壁碳纳米管的前四阶固有频率,并分析了碳纳米管非局部参数、黏弹性参数、基底刚度及长度等影响因素对固有频率和阻尼因子的影响情况。结果表明,文中所建的动力学分析模型及计算方法对解决碳纳米管在黏弹性基底上的动力学问题准确有效。     

基于时空序贯融合的TBM拦截效果评估

基于时空信息进行了TBM拦截效果评估的研究。首先分析了拦截效果评估信息的特征,建立了TBM拦截效果评估流程;在此基础上提出了基于"空间特征级-时间决策级"思想的序贯融合评估模型;融合评估算法中,空间域选取模糊神经网络进行特征级融合,时间域选取D-S证据理论完成决策级融合,空间特征级融合模糊神经网络的各层映射函数分别由模糊隶属函数和采用贝叶斯网络的方法来获取;最后通过实验仿真了评估流程,验证了融合评估模型及融合算法的有效性。     

一种改进的证据理论合成规则

随着证据理论在信息融合领域中的广泛应用,对冲突证据的处理成为证据理论和应用研究热点。提出了一种基于证据重要度和聚焦度的新的合成规则,首先根据各个证据的重要度对冲突证据进行修正,再对冲突进行细化并考虑证据焦元的基数对D-S合成法则的影响,将冲突信息提取后加入组合规则中。通过实验比较和分析,结果说明该方法不仅能够处理一般性冲突问题,也能处理"一票否决"和"鲁棒性"问题。