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301.
提出了非致命防暴动能弹作战效能的评估法,分析了非致命防暴动能弹的技术性能,建立了以非致命性为核心指标的防暴动能弹效能指标体系。采用定性分析与定量分析相结合,将集对分析法应用到了非致命防暴动能弹的效能评估中,对3种防暴动能弹进行了效能评估。为非致命防暴动能弹的研发生产提供了重要的理论支撑。  相似文献   
302.
本文证明了二部图存在(g,f)匹配和f 因子的充要条件以及有关的几个结果,并且给出了求二部图的最大(g,f)匹配、最小(g,f)匹配和最小权最大f 匹配、最小权(g,f)匹配、最大权(g,f)匹配的算法。  相似文献   
303.
随着无人机作业空域从中高空不断向低空甚至超低空拓展,复杂的低空障碍环境对无人机造成了严重的威胁。研究无人机避障航路规划理论与方法,对于保障无人机的飞行安全和提升其任务效率具有重要作用。对无人机避障航路规划方法的研究现状进行了梳理,首先,根据航路规划问题所建立的优化模型,将规划方法划分为基于数学规划的方法、基于路标图的方法、基于空间分解的方法、基于势场的方法、基于随机规划的方法和基于机器学习的方法六个大类。然后,分别介绍了各类型方法的基本原理、代表性研究以及优缺点。最后,对避障航路规划方法未来可能的研究方向进行了展望。综述表明,复杂环境下无人机三维航路规划方法的研究仍有提升空间;未来应考虑将传统规划方法与新一代人工智能技术相结合;航路规划方法研究应充分考虑机载传感器的实际性能和工作特性;规划航路的可跟踪性问题也亟待解决。  相似文献   
304.
《防务技术》2020,16(5):1062-1072
Recent years have seen an explosion in graph data from a variety of scientific, social and technological fields. From these fields, emotion recognition is an interesting research area because it finds many applications in real life such as in effective social robotics to increase the interactivity of the robot with human, driver safety during driving, pain monitoring during surgery etc. A novel facial emotion recognition based on graph mining has been proposed in this paper to make a paradigm shift in the way of representing the face region, where the face region is represented as a graph of nodes and edges and the gSpan frequent sub-graphs mining algorithm is used to find the frequent sub-structures in the graph database of each emotion. To reduce the number of generated sub-graphs, overlap ratio metric is utilized for this purpose. After encoding the final selected sub-graphs, binary classification is then applied to classify the emotion of the queried input facial image using six levels of classification. Binary cat swarm intelligence is applied within each level of classification to select proper sub-graphs that give the highest accuracy in that level. Different experiments have been conducted using Surrey Audio-Visual Expressed Emotion (SAVEE) database and the final system accuracy was 90.00%. The results show significant accuracy improvements (about 2%) by the proposed system in comparison to current published works in SAVEE database.  相似文献   
305.
In the context of restricted budgetary resources and the growing cost of maintenance, repair, and overhaul (MRO) activities, a major issue for modern armed forces is to sustain defense platforms. A possible method consists of realizing economies of scale through the concentration of maintenance activities, which involves the spatial reorganization of existing industrial sites dedicated to MRO. This article provides a formalized framework to discuss the optimal organization for the MRO of defense platforms in space. The public planner organizes the maintenance of defense platforms with only two possible spatial configurations. In the dispersed configuration, two industrial production units in charge of the maintenance optimally cover space, whereas in the concentrated configuration, a unique industrial unit covers space. Focusing on the tipping point between the two configurations, the balance of forces between agglomeration and dispersion in defense support activities is described and discussed. On the one hand, economies of scale provide an opportunity to optimize defense support costs, favoring concentration in a unique industrial unit. On the other hand, space causes dispersion to reduce both transport costs and operational social costs. This trade-off illustrates a general principle in spatial economics with an application to MRO production in the French case.  相似文献   
306.
We consider the decision‐making problem of dynamically scheduling the production of a single make‐to stock (MTS) product in connection with the product's concurrent sales in a spot market and a long‐term supply channel. The spot market is run by a business to business (B2B) online exchange, whereas the long‐term channel is established by a structured contract. The product's price in the spot market is exogenous, evolves as a continuous time Markov chain, and affects demand, which arrives sequentially as a Markov‐modulated Poisson process (MMPP). The manufacturer is obliged to fulfill demand in the long‐term channel, but is able to rein in sales in the spot market. This is a significant strategic decision for a manufacturer in entering a favorable contract. The profitability of the contract must be evaluated by optimal performance. The current problem, therefore, arises as a prerequisite to exploring contracting strategies. We reveal that the optimal strategy of coordinating production and sales is structured by the spot price dependent on the base stock and sell‐down thresholds. Moreover, we can exploit the structural properties of the optimal strategy to conceive an efficient algorithm. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010  相似文献   
307.
The reformulation‐linearization technique (RLT) is a methodology for constructing tight linear programming relaxations of mixed discrete problems. A key construct is the multiplication of “product factors” of the discrete variables with problem constraints to form polynomial restrictions, which are subsequently linearized. For special problem forms, the structure of these linearized constraints tends to suggest that certain classes may be more beneficial than others. We examine the usefulness of subsets of constraints for a family of 0–1 quadratic multidimensional knapsack programs and perform extensive computational tests on a classical special case known as the 0–1 quadratic knapsack problem. We consider RLT forms both with and without these inequalities, and their comparisons with linearizations derived from published methods. Interestingly, the computational results depend in part upon the commercial software used. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2010  相似文献   
308.
基于粗精度DEM的复杂地形InSAR基线估计方法   总被引:4,自引:1,他引:3       下载免费PDF全文
基线精度对合成孔径雷达干涉测量极其重要,在研究传统基线估计方法的基础上,提出了一种基于粗精度DEM的基线估计方法。利用SRTM数字高程及初始轨道数据去除干涉相位中的地形条纹,通过分析剩余条纹的空间频率估计精确基线,具有不依赖于精确轨道数据、不受地形限制的优点。利用西藏玛尼山区ERS1/2数据进行了实测数据验证,实验结果表明得到的基线精度优于传统方法。  相似文献   
309.
针对单一算法对混合尺寸目标进行时域电磁分析的困难,提出一种时域伪谱(PSTD)同时域有限体积(FVTD)混合方法。FVTD可方便地分析复杂的几何结构和材料,但是难以计算电大尺寸的目标,PSTD则特别适合计算电大尺寸的规则结构,但在模拟复杂的几何结构尤其是带有曲边结构以及电大、电小共存结构时存在困难。混合方法克服了单独算法的缺点,融合各自的优势,提高了算法的求解能力和应用范围。为了减小两种算法连接边界带来的反射,采用了FVTD计算面均值的二次函数重构方法,给出了交叠网格和非交叠网格两种混合方案。数值试验表明,混合方法有较高的精度,具有时域分析混合尺寸目标电磁问题的能力。  相似文献   
310.
提出了一种应用准静态技术,结合快速多级子算法计算任意形状的运动目标多普勒信号的方法,对目标的几种典型的微动多普勒信号进行了仿真,并应用高分辨时频分析算法对仿真得到的微多普勒信号进行了分析,提取出了微多普勒瞬时频率,并与相应微动规律的点目标微多普勒瞬时频率进行对比。结果表明,二者具有相同的变化规律,从而证明本文提出的方法是有效的。  相似文献   
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