余模范畴上单子的构造

根据A-上环（A是代数）的类群元的定义及有关性质，文章首先给出T-余单子（T是单子）的类群元的定义、存在条件，其次研究了类群元与缠绕结构之间的相关性质，最后构造了T-余模范畴上的单子。     

试验函数空间的非标准包

本文研究了试验函数空间Ｄ（Ω）的非标准包（Ｄ）＾及其性质,并给出了（Ｄ）∧中元素的构造。最后,证明了（Ｄ）∧与Ｄ（Ω）有着类似的结构,而且（Ｄ）∧也可作为一类局部凸空间的严格归纳极限     

采用随机矩阵理论的水声阵列SMI-MVDR空间谱估计技术

对角加载MVDR技术是一种经典的空间谱估计技术,在水声阵列信号处理中有着广泛的应用。该技术之所以具有较好的性能是由于其通过对角加载使样本协方差矩阵的特征值分散度减小。提出了基于随机矩阵理论的MVDR空间谱估计技术,具体思路是利用随机矩阵特征值的极限性质实现样本协方差矩阵噪声的抑制,以达到类似对角加载能够实现的特征值分散度减小的效果。仿真表明所提出的方法与对角加载方法达到了同样的目的,且当快拍数一定,而信噪比由小变大时,该方法可以达到与对角加载MVDR技术相当的性能;当信噪比设为定值,快拍数由小变大时,其与对角加载技术具有相同的DOA估计成功概率变化趋势,且在小样本情况下,此方法优势较为明显。     

一种新型双频双感圆极化方形环缝隙天线

文章设计了一种新型双频双感圆极化方形环缝隙天线。通过在接地板上开两个方形环缝隙,并改变方形环缝对角处的缝隙宽度形成微扰,从而分离谐振模来实现该天线的双频圆极化辐射。两个微扰结构关于馈电微带对称放置,则形成双频双感圆极化辐射。对该天线进行了仿真、制作和测试,仿真和测试结果表明,该天线在两个频带都具有良好的圆极化辐射效果。     

二元对角矩阵Pade逼近

Chisholm在他的文章[1]中给出了二元对角Pade逼近并证明了这种逼近的若干不变性质,本文将二元对角Pade逼近推广到二元对角矩阵Pade逼近并研究了它的若干性质。     

基于凸优化提高MIMO-STAP检测性能的波形设计

考虑了复杂环境下改善基于多输入多输出正交频分复用(MIMO-OFDM)雷达的空时自适应处理(STAP)检测性能的波形优化问题。基于最大化输出信干噪比(SINR)准则,推导了改善STAP检测性能,且具有恒模约束的波形优化问题。为求解所得复杂非线性优化问题,将非凸约束-恒模约束,松弛为凸约束-低峰均比(PAR)约束,以降低运算复杂度从而利于工程应用。提出一种基于对角加载(DL)的新方法,以将此问题转化为半定规划问题(SDP),因而可获得高效求解,从而便于硬件实现。仿真表明:相较于不相关波形以及MIMO-STAP方法,所提方法可显著提高STAP检测性能。     

分块模幂算法

RSA是目前最成熟的一种公钥密码体系 ,RSA加解密算法的速度依赖于模幂算法 ,因而快速模幂算法一直是人们感兴趣的课题。该文提出了一种基于分块的模幂算法 ,对算法复杂性进行了讨论 ,并与其他模幂算法作了比较 ,从理论上论证了它具有更快的模幂速度     

盲信道均衡的动量恒模算法

介绍了盲信道均衡恒模算法(CMA)的基本原理,对恒模算法的缺点进行了分析,通过修正恒模算法的迭代公式提出一种动量恒模算法(MCMA)。利用QPSK信号,采用计算机仿真的方法对动量恒模算法与恒模算法进行盲均衡性能比较,模拟结果显示,MCMA算法比CMA算法在收敛速率、降低稳态均方误差和符号间干扰具有明显的优势,有效地改进了信道均衡性能。     

基于角反射器的诱扫主动攻击水雷方法

针对现有对抗主动攻击水雷方法的不足，根据主动攻击水雷工作特点，提出了利用串联角反射器模拟潜艇声反射，结合声扫雷具模拟潜艇声辐射，联合诱骗主动攻击水雷的方法。建立了模拟潜艇声反射强度计算模型，给出了从声反射强度及尺度特征方面模拟潜艇特征的方法，并进行了初步验证。为便于使用及提高对抗效率，对角反射器的类型、边长及构造进行了深度优化，显著提高了对抗主动攻击水雷时的效率，证明了该方法的有效性。     

叠加导频的放大转发协作通信系统时变信道估计方法

在基于正交频分复用技术的放大转发协作通信系统中,针对整体中继信道估计(S-R-D)辅助导频占用额外带宽使带宽利用率低的缺点以及传统叠加导频信道估计性能不高的缺点,提出了一种新的对角叠加导频方案。在不增加导频数量的前提下,将叠加导频的位置由传统的块状叠加变为对角叠加后,信道估计性能优于传统叠加导频方案和辅助导频方案,且与理想信道估计性能接近。仿真结果表明:和传统方法相比,采用对角叠加导频方案不仅提高了信道估计精度和带宽利用率,而且可以较好地跟踪信道的变化。     

Algorithms for minimizing total cost,bottleneck time and bottleneck shipment in transportation problems

We consider the transportation problem of determining nonnegative shipments from a set of m warehouses with given availabilities to a set of n markets with given requirements. Three objectives are defined for each solution: (i) total cost, TC, (ii) bottleneck time, BT (i.e., maximum transportation time for a positive shipment), and (iii) bottleneck shipment, SB (i.e., total shipment over routes with bottleneck time). An algorithm is given for determining all efficient (pareto-optimal or nondominated) (TC, BT) solution pairs. The special case of this algorithm when all the unit cost coefficients are zero is shown to be the same as the algorithms for minimizing BT. provided by Szwarc and Hammer. This algorithm for minimizing BT is shown to be computationally superior. Transportation or assignment problems with m=n=100 average about a second on the UNIVAC 1108 computer (FORTRAN V)) to the threshold algorithm for minimizing BT. The algorithm is then extended to provide not only all the efficient (TC, BT) solution pairs but also, for each such BT, all the efficient (TC, SB) solution pairs. The algorithms are based on the cost operator theory of parametric programming for the transportation problem developed by the authors.     

卫星姿控实物仿真系统中的磁线圈分析

报道利用两对赫姆霍兹线圈模拟卫星的磁环境的研究。首先分析了赫姆霍兹线圈产生磁场的均匀度 ,接着分析了单一线圈安装和形状偏差对产生磁场的影响 ,然后提出地球磁场模拟方案 ,最后给出仿真结果和分析结论     

散度、旋度和梯度在共同模式上的统一定义及其在一般坐标系中的应用

本文在推广的散度定理的基础上给出了散度、旋度和梯度与坐标无关的统一定义。着重在一般曲线坐标系中利用以三对坐标面为包容面的微元体为共同模式,把散度、旋度和梯度统一表示为某一微分量的极限值,从而直接导出了张量分析中这三种量的熟知的表达式。     

火力使用策略的集对分析与评价

对不确定理论──集对分析理论［１］中关于联系度的算法作了修改,给出了更有实际意义的联系度公式。应用此公式采用同异反决策分析的方法,首先对“火力使用策略”进行定性分析,把影响火力使用的７对主要矛盾看作７个集对,定义每集对的同异反三属性的测量要素。通过求各集对的联系度所在问题的解,达到择优最佳“火力使用策略”的目的,从而对战役行动起到指导或辅助决策的作用。     

The formulation of some allocation and connection problems as integer programs

In this paper a component placement problem and a digital computer backboard wiring problem are formulated as integer linear programs. The component placement problem consists of making a unique assignment of components to column positions such that wireability is maximized. The backboard wiring problem consists of three interrelated subproblems, namely, the placement, the connection, and the routing problems. The placement and connection problems are combined and solved as one, thereby giving the optimal circuit connections as well as minimizing the total lead length. It is shown that under certain assumptions, the number of inequalities and variables in the problem can be greatly reduced. Further simplifying assumptions lead to a near optimal solution. Examples of other allocation problems to which the models presented here are applicable are given. The following concepts are formulated as linear inequalities: (1) the absolute magnitude of the difference between two variables; (2) minimize the minimum function of a set of functions; and (3) counting the number of (0, 1) adjacent component pairs in a vector.     

A hybrid algorithm for the one machine sequencing problem to minimize total tardiness

In a recent paper, Hamilton Emmons has established theorems relating to the order in which pairs of jobs are to be processed in an optimal schedule to minimize the total tardiness of performing n jobs on one machine. Using these theorems, the algorithm of this paper determines the precedence relationships among pairs of jobs (whenever possible) and eliminates the first and the last few jobs in an optimal sequence. The remaining jobs are then ordered by incorporating the precedence relationships in a dynamic programming framework. Propositions are proved which considerably reduce the total computation involved in the dynamic programming phase. Computational results indicate that the solution time goes up less than linearly with the size (n) of the problem. The median solution time for solving 50 job problems was 0.36 second on UNIVAC 1108 computer.     

Partial input to output impacts in DEA: Production considerations and resource sharing among business subunits

Data envelopment analysis (DEA) is a methodology for evaluating the relative efficiencies of peer decision‐making units (DMUs), in a multiple input/output setting. Although it is generally assumed that all outputs are impacted by all inputs, there are many situations where this may not be the case. This article extends the conventional DEA methodology to allow for the measurement of technical efficiency in situations where only partial input‐to‐output impacts exist. The new methodology involves viewing the DMU as a business unit, consisting of a set of mutually exclusive subunits, each of which can be treated in the conventional DEA sense. A further consideration involves the imposition of constraints in the form of assurance regions (AR) on pairs of multipliers. These AR constraints often arise at the level of the subunit, and as a result, there can be multiple and often inconsistent AR constraints on any given variable pair. We present a methodology for resolving such inconsistencies. To demonstrate the overall methodology, we apply it to the problem of evaluating the efficiencies of a set of steel fabrication plants. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

渐开线环形齿球齿轮传动时变刚度系数

为研究渐开线环形齿球齿轮传动过程中齿轮副间的接触力,基于Hertz弹性接触理论定义了齿面接触点的刚度系数;利用微分几何相关知识,分析了球齿轮的齿面特征,得到了实时啮合点主曲率半径计算公式;研究了重合度系数对啮合刚度的影响,结合球齿轮机构传动特点,推导出任意位置反向啮合点位置计算公式;最后通过一个实例说明球齿轮机构接触点刚度系数具有典型的时变特征.     

一种直线段匹配的新方法

直线特征在人造目标和环境中普遍存在,直线段的匹配是三维重建等应用领域的首要解决问题.一般单直线的匹配方法难以解决被部分遮挡直线的匹配问题,提出了一种基于极线约束和RANSAC算法的匹配方法.对直线段上的点运用基于极线约束的匹配方法在另一幅图像中进行点的同名匹配,采用RANSAC算法建立直线模型,剔除野值,得到匹配直线段.本方法能有效地解决图像中被部分遮挡直线段的匹配问题,仿真实验和实际图像实验证实了本算法的正确性和高精度.