舰船固定磁场分量分离的一种新方法

为了准确了解舰船的固定磁场分布,进而对舰船磁性防护作出指导,用等效磁偶极子的方法对舰船固定磁场分量分离的方法进行了研究,通过对固定磁场垂直分量总和的曲线进行分析,根据磁偶极子组合产生磁场规律的先验知识,选择最佳的磁偶极子的排列方式,然后对磁偶极子磁矩范围进行估计,最后利用遗传算法这种全局优化算法求出磁源的参数,进而分离出固定磁场各个分量。仿真计算结果表明,该方法能够比较好地搜索到磁偶极子的最佳数目、位置和磁矩,可以用于舰船固定磁场的分离。     

Interval scheduling: A survey

In interval scheduling, not only the processing times of the jobs but also their starting times are given. This article surveys the area of interval scheduling and presents proofs of results that have been known within the community for some time. We first review the complexity and approximability of different variants of interval scheduling problems. Next, we motivate the relevance of interval scheduling problems by providing an overview of applications that have appeared in literature. Finally, we focus on algorithmic results for two important variants of interval scheduling problems. In one variant we deal with nonidentical machines: instead of each machine being continuously available, there is a given interval for each machine in which it is available. In another variant, the machines are continuously available but they are ordered, and each job has a given “maximal” machine on which it can be processed. We investigate the complexity of these problems and describe algorithms for their solution. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

基于附加频移跳频的方案设计及其性能分析

为了提高跳频系统的抗预测性能,增大抗跟踪干扰能力,提出了基于附加频移的跳频通信。在给定跳频带宽内,该方案通过双序列的控制输出射频频率来提高其跳变复杂度,从而增大敌方对于跳频序列的正确建模和预测难度。基于混沌特性的分析方法,对采用L-G非连续抽头模型和Logistic-Kent级联映射构造的合成跳频序列的复杂度进行了计算,与相同模型下构造的常规跳频序列相比,基于附加频移的跳频通信均具有更大的复杂度。     

多核数字信号处理器矩阵乘卷积算法性能评测

矩阵乘卷积算法能够为各种卷积配置提供高性能基础实现,是面向给定芯片进行卷积性能优化的首要选择。针对国防科技大学自主研制的飞腾异构多核数字信号处理器(digital signal processor, DSP)芯片的特征以及矩阵乘卷积算法自身的特点,提出了一种面向多核DSP架构的高性能并行矩阵乘卷积实现算法ftmEConv。该算法由输入特征图转换、卷积核转换、矩阵乘以及输出特征图转换这四个均运行在通用多核DSP上的并行化部分构成,通过有效挖掘通用DSP核中功能单元的潜力来提升各个部分的性能。实验结果表明,ftmEConv实现了高达42.90%的计算效率,与芯片上的其他矩阵乘卷积算法实现相比,获得了高达7.79倍的性能加速。     

保证率点值区间估计的Monte-Carlo方法

提出了一种根据实测样本系列对保证率点值进行区间估计的Ｍｏｎｔｅ─Ｃａｒｌｏ方法。对于具有正态分布或对数正态分布的样本,首先推出总体参数的分布,然后用Ｍｏｎｔｅ─Ｃａｒｌｏ法生成总体参数系列,据此求得相应的保证率点值系列,最后通过经验分布推得在给定置信度下保证率点值的区间估计,本文还给出了一个算例。     

改进的精密三点法——在线测量直线度方法的再探讨

在原精密三点法的基础上,对插值方法进行了改进,对随机误差采用了相应的数据处理方法,使得分离结果更加接近真实值,并有效地去除了随机误差的影响,得到了采样值加密的曲线,文中给出了改进的精密三点法的算法和流程图。从仿真和实验结果来看,该方法是具有可行性和可靠性的。     

C76、C78、C82、C84和C90的π电子磁化率

采用规范不变分子轨道方法,计算了Ｄ_２—Ｃ_（７６）、Ｃ_（２ｖ）￣－和Ｄ_３—Ｃ_（７８）、Ｃ_２—Ｃ_（８２）、Ｄ_２—和Ｄ_（２ｄ）—Ｃ_（８４）以及Ｃ_２—Ｃ_（９０）的л电子磁化率。其结果表明这些纯碳原子团簇分子具有较大的抗磁磁化率。反映出这些分子具有一定的芳香性及其л电子有较大的共有化运动程度。     

计算思维的培养与实践

计算思维着眼于问题求解和机器实现,强调运用计算机解决问题的能力。从培养军校学员计算思维能力出发,对“计算机网络”课程教学进行了探讨和研究,采用内容重组、创新教法与学科融合相结合的方式,将思维训练融入教学实践。统计结果显示,新的教学模式能使学员更高效、更深入地理解和掌握计算机网络的基本概念、原理和体系结构,提升学员的综合素质和创新能力。     

基于支持向量机的制造系统静态复杂性综合模型研究

制造系统复杂性对优化制造系统结构设计、提高制造系统的生产效率具有非常重要的意义.然而目前对静态复杂性及动态复杂性影响因素复杂性及其测度的研究较多,对于如何将这些分因素复杂性进行综合得出综合复杂性的研究较少,这直接影响了复杂性研究结果的准确性。鉴于此,引入擅长处理小样本数据的支持向量机对制造系统静态复杂性进行综合,用遗传算法对其参数进行寻优,对模型的有效性进行了验证,结果说明方法的实用性与科学性较强.     

Multidirectional scheduling scheme in resource‐constrained project schedulingproblem

In 2000, Klein showed that bidirectional scheduling schemes (bidss) outperform single‐directional scheduling schemes (e.g., forward or backward schemes). In 2010, Yoosefzadeh, et al. [J Math Model Algor 9 (2010), 357–373] showed that depending on the nature of the problems and also the type of priority rules used, schedules produced by a so‐called tridirectional scheduling scheme (trdss) yields shorter makespans when compared to forward, backward, and even bidss. Since the justification technique is applied in many of the state‐of‐the‐art algorithms nowadays, we show that the tuned version of the trdss outperforms the double justification technique. Moreover, we investigate the circumstances under which the trdss is more probable to generate schedules with shorter makespans. To this end, we introduce a new measure of resource requirements and their distributions, namely total amount of overflows. Our analytical as well as empirical investigations show that when the new measure is increased, it is more probable to obtain schedules with shorter makespans using the trdss. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 61: 44–55, 2014