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91.
基于风险理论提出一种面向不同目标探测任务的传感器调度方法。将主动传感器辐射被截获风险和目标探测风险结合起来,建立一般目标探测框架下的传感器最小风险调度模型。分目标跟踪、目标识别和目标威胁等级评估三种情况将传感器最小风险调度模型具体化,给出不同情况下目标探测风险值的计算方法。针对模型的求解提出一种基于混沌思想、反向学习和双向轮盘赌的改进人工蜂群算法。通过仿真实验证明了模型的可行性和算法的有效性。 相似文献
92.
In this paper, a condition-based maintenance model for a multi-unit production system is proposed and analyzed using Markov renewal theory. The units of the system are subject to gradual deterioration, and the gradual deterioration process of each unit is described by a three-state continuous time homogeneous Markov chain with two working states and a failure state. The production rate of the system is influenced by the deterioration process and the demand is constant. The states of the units are observable through regular inspections and the decision to perform maintenance depends on the number of units in each state. The objective is to obtain the steady-state characteristics and the formula for the long-run average cost for the controlled system. The optimal policy is obtained using a dynamic programming algorithm. The result is validated using a semi-Markov decision process formulation and the policy iteration algorithm. Moreover, an analytical expression is obtained for the calculation of the mean time to initiate maintenance using the first passage time theory. 相似文献
93.
为提高潜艇磁隐身能力,应对潜艇固定磁场进行实时监测,提出利用最小二乘支持向量机的潜艇内外磁场映射方法。结合内外映射法和最小二乘支持向量机原理,通过交叉验证优化模型参数,建立由内到外的潜艇磁场映射模型。以潜艇外部垂向固定磁场变化量为分析对象,仿真和实验结果均与标准值吻合良好。与径向基神经网络算法相比,该方法的泛化能力和推算精度有明显提高,且更符合工程实际,对闭环消磁技术的研究具有指导意义。 相似文献
94.
95.
《防务技术》2020,16(2):425-431
This work describes the preparation and study of the properties of composite nanoparticles prepared by the sol-gel method which consists of two materials (Al2O3-CaO), and study the effect of these nanoparticles on the mechanical behavior of a polymer blend (EP 4% + 96% UPE). The powder was evaluated by X-ray diffraction analysis, scanning electron microscopy analysis (SEM), particle size analysis, and energy dispersive X-ray analysis (EDX). The mechanical behavior of the composite material was assessed by tensile test, bending test and hardness test. The evaluation results of the composite nanoparticles showed good distribution of the chemical composition between aluminum oxide and calcium oxide, smoothness in particles' size at calcination in high and low temperatures, formation of different shapes of nanoparticles and different (kappa and gamma) phases of the Al2O3 particles. The results of mechanical behavior tests showed marked improvement in the mechanical properties of the resulted composite material, especially at 1.5%, compared with polymer blend material without nano powder addition. The tensile properties improved about (24 and 14.9) % and bending resistance about (23.5 and 16.8) % and hardness by (25 and 22) % when adding particles of size (63.8 and 68.6) respectively. Therefore, this reflects the efficiency of the proposed method to manufacture the nanocomposite powder and the possibility of using this powder as a strengthening material for the composite materials and using these composite materials in bio applications, especially in the fabrication of artificial limbs. 相似文献
96.
《防务技术》2020,16(1):18-28
Under the background of vigorously developing facilities of island/reef in the world, the economic value and strategic significance of the island/reef have become increasingly important. Unfortunately, they may easily become the attacking target of missiles in the war time. Therefore, aiming at the damage quantification of the targets in the island/reef under the missile attacking, a macroscopic damage assessment model for the target area is proposed in this paper. The model focuses on the construction of the assessment model framework. Firstly, the analytic hierarchy process and the grey relational analysis are applied to measure the importance of each target in the region through four indicators of the target hazard, striking urgency, damage advantage and mission relevance, respectively. Secondly, based on the damage mechanism of shock wave and fragments to target, the corresponding damage model is established, and the damage grade of each target in the evaluated area is obtained according to the damage criteria and grading standard. Finally, the model obtains the overall damage grade of the target area by employing the fuzzy comprehensive evaluation method, with synthesizing the importance and the damage grade of each target. Through the verification of an example, it demonstrates the certain feasibility of the model and provides a certain basis and reference for the subsequent research. 相似文献
97.
《防务技术》2020,16(5):1073-1087
Because of the uncertainty and subjectivity of decision makers in the complex decision-making environment, the evaluation information of alternatives given by decision makers is often fuzzy and uncertain. As a generalization of intuitionistic fuzzy set (IFSs) and Pythagoras fuzzy set (PFSs), q-rung orthopair fuzzy set (q-ROFS) is more suitable for expressing fuzzy and uncertain information. But, in actual multiple attribute decision making (MADM) problems, the weights of DMs and attributes are always completely unknown or partly known, to date, the maximizing deviation method is a good tool to deal with such issues. Thus, combine the q-ROFS and conventional maximizing deviation method, we will study the maximizing deviation method under q-ROFSs and q-RIVOFSs in this paper. Firstly, we briefly introduce the basic concept of q-rung orthopair fuzzy sets (q-ROFSs) and q-rung interval-valued orthopair fuzzy sets (q-RIVOFSs). Then, combine the maximizing deviation method with q-rung orthopair fuzzy information, we establish two new decision making models. On this basis, the proposed models are applied to MADM problems with q-rung orthopair fuzzy information. Compared with existing methods, the effectiveness and superiority of the new model are analyzed. This method can effectively solve the MADM problem whose decision information is represented by q-rung orthopair fuzzy numbers (q-ROFNs) and whose attributes are incomplete. 相似文献
98.
The aim of this paper is to investigate the determinants of international arms transfers in a gravity model framework. By distinguishing between the decision to export arms (extensive margin) and the value of the arms exported (intensive margin), while also considering its interdependence, is what differentiates this paper from previous research. A theoretically justified gravity model of trade augmented with political and security motives is estimated using a two-stage panel data approach for 104 exporting countries over the period from 1950 to 2007. In addition to the usual gravity variables related to the economic mass of the trading countries and the trade cost factors, the model is extended with political and security factors. The level of democracy in both trading partners, political differences between trading partners and voting similarity with the United States in the UN General Assembly of the countries engaged in trade are the main political factors, whereas the existence of conflicts, military pacts, and embargoes are taken as security motives. The key result indicates that both political and security motives are an important determinant of an arms trade, but their effects on the extensive margin of exports (the decision to order a transfer) differs from their effect on the intensive margin (average value of exports). Moreover, the relative importance of the factors under study has changed since 1989. In the post-cold war period, countries that are less democratic are more likely to export arms, military pacts are less relevant and embargoes play a role. 相似文献
99.
Thomas Waldman 《Defence Studies》2019,19(1):85-105
This paper explores the notion that US efforts to evade the political costs of war paradoxically contribute to the subsequent exacerbation of costs over time. Leaders seek to purchase political capital in the short term by limiting the costs and requirements of military operations, but in doing so cause strategic and political liabilities to mount in the long run. While identification of such behaviour is not new, insufficient attention has been devoted to explaining its causes, dynamics, and manifestations in relation to key decisions on and in war. Evidence derived from studies of recent American discretionary campaigns is analysed to advance an argument with respect to this pattern of self-defeating strategic behaviour. 相似文献
100.
Michael H. Clemmesen 《Defense & Security Analysis》2019,35(1):96-97
The article outlines the essential role of free play elements in various types of exercises for the development of in-depth and practical military professionalism. It thereafter argues why such use of free play contradicts the military science founded Russian Way of War. 相似文献