一种基于目标的雷达对抗侦察策略

传统的电子战接收系统的搜索方式主要针对参数完全未知的敌方信号,通过在频域、空域等各维度进行大范围的逐段重复搜索可在较长时间内获得较好的侦察效果,但不适合短时间内对特定目标群的搜索和验证。针对电子战接收机存在的盲目侦察接收、与作战目标结合不紧密等问题,提出了一种基于作战目标的侦察策略,能够智能引导超外差接收机进行搜索截获,有效提升了超外差接收机对重点目标的实时截获与准确识别能力。     

带落角约束的再入机动弹头的复合导引律

针对再入机动弹头垂直打击目标的要求,研究了具有末端落角约束的复合导引律.该导引律包括俯冲平面内的制导方程和转弯平面内的制导方程,通过在最优导引律的基础上引入滑模变结构控制,增强导引律的鲁棒性.为了减小控制量的抖振和能量损耗,提出了采用RBF(径向基函数)神经网络自适应调节切换项增益的方案,数学仿真验证了该方案的有效性.仿真结果还表明,与最优导引律相比,复合导引律在外界干扰的影响下仍能保持较高的制导精度.     

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.     

一种面向任务的通用仿真资源集成管理平台的设计与实现

针对当前仿真领域中对仿真资源可重用性的需求,根据实践经验及相关理论知识对仿真资源管理系统的设计与实现进行了研究。提出了一种面向任务的通用仿真资源集成管理平台,该平台用面向任务的视角集成管理资源,以B/S系统结构及Web服务技术保证其通用性,以细粒度的用户验证机制保证其安全性。通过对实际原型系统的测试,与其它同类系统比较,该资源管理平台具有明显优势,能够很好的满足仿真资源管理的需求,并具有较强的通用性。     

Democracy index for Africa, 2010

ABSTRACT

Natural resource-based conflicts continue to occur in different parts of Nigeria with negative implications. This study investigated the phenomena of natural resource conflicts vis-à-vis their propensities to impact political economy and national security negatively. Data for the study were sourced from theoretical and empirical evidence. Empirical data were sourced from existing studies selected on the basis on their relevance to the study and analysed based on their content. The limitation to this approach is the obsolete and subjective nature of some the literature. This limitation was, however, addressed among others through the author’s knowledge of the issues under study. The study found that Nigeria is enmeshed in conflict over ownership, distribution, access to or competition over natural resources such as petroleum resources and agricultural land and these conflicts have undermined democracy, human rights, the economy and the nation’s security. The paper identified poor resource governance, environmental factors and poor political leadership as the causes and drivers of these conflicts. It recommends natural resource governance among others, as a way out of the problem.     

车载多接入边缘网络中联合资源分配和动态任务卸载方案

针对车联网中车辆移动速度过快产生的任务卸载失败问题,设计了一个有效的任务卸载风险评估模型,并提出了联合资源分配的动态任务卸载方案。将时间、能耗和风险共同建模为系统效用,通过联合优化卸载决策、资源分配来最大化系统效用。优化问题被公式化为混合整数非线性规划,在给定卸载决策的情况下,利用凸优化技术解决计算资源分配问题,功率分配通过分式规划技术来优化。仿真分析了车辆移动性对系统效用的影响,证明了所提方案的合理性。     

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     

Some probability functions in reliability and their applications

There has been much research on the general failure model recently. In the general failure model, when the unit fails at its age t, Type I failure (minor failure) occurs with probability 1 ? p(t) and Type II failure (catastrophic failure) occurs with probability p(t). In the previous research, some specific shapes (constant, non‐decreasing, or bathtub‐shape) on the probability function p(t) are assumed. In this article, general results on some probability functions are obtained and applied to study the shapes of p(t). The results are also applied to determining the optimal inspection and allocation policies in maintenance problems. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

基于STN的任务执行过程中的资源冲突自动消解

任务在执行过程中受到各种因素的影响,任务时间可能会偏离预定计划,在资源数量有限的情况下,由于要满足时间的约束,往往会出现时间重叠而发生资源冲突。消解这种资源冲突的一个最直接的方法是及时调整任务计划时间消解潜在的资源冲突。针对任务执行过程中冲突消解人工决策耗时较长的问题,设计了一种基于STN的任务在执行过程中的自动消解方法,通过案例仿真,证明方法是可行的,并且能够比人工决策方式节约时间。     

结合局部描述和拓扑约束的直线段匹配算法

针对弱纹理目标匹配问题,提出了一种基于直线局部邻域梯度信息和全局结构信息的直线匹配算法:对均值标准差直线描述符进行改进用于初始匹配;利用直线间的全局拓扑结构滤除误匹配;利用迭代拓扑滤波寻找更多的匹配,同时引入全局角度约束提高算法效率并进一步滤除错误匹配。实验表明,在光照变化、图像旋转、图像模糊、尺度变换、视点变化等条件下,该方法都具有很强的鲁棒性,并在匹配效率和准确度上优于现有的两种比较流行的方法。