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排序方式: 共有3238条查询结果,搜索用时 15 毫秒
921.
针对规则空间下集群运动问题,开展了基于多区域模糊控制(MRFC)-Vicsek模型的集群控制方法的研究.考虑到仿生集群在运动时的行为准则,首先建立了包括避碰层、一致层、内聚层、连通层在内的多区域Vicsek模型.其次,通过模糊规则将不同区域个体数量和集群拥挤程度转化为对中心个体的影响权重,再结合规则空间内边界对个体的影... 相似文献
922.
923.
信息与通信技术是影响国家政治、经济和军事等重要领域的高精尖技术。本文认为,美国政府通过启动"301调查"和建立出口管制实体清单等多种方式对中国信息与通信领域实施技术封锁和产品禁运,将延缓中国信息与通信技术的发展进度,加大全球信息与通信技术产业发展的成本消耗,但同时也刺激并加快了中国信息与通信技术自主可控的转型步伐。据此,本文提出加强顶层设计和统筹谋划、营造自主可控的产业生态环境、加强专业化人才队伍培养、构建合作共赢的命运共同体,努力突破信息与通信技术封锁等几项措施,以期为我国信息与通信技术领域的发展提供一定的借鉴意义。 相似文献
924.
925.
Edoardo Baldaro 《Small Wars & Insurgencies》2018,29(3):579-603
AbstractThis article analyses changes and failures in the northern Mali system of security governance, taking into account the period running from the declaration of the Malian Third Republic (1992) to the present. Considering northern Mali as an area of limited statehood, the article develops a comparative diachronic analysis, distinguishing between three phases, namely Militiarisation (1992–2002), Fragmentation (2002–2012) and Multiplication (2013–ongoing). For every phase the focus is on (1) the mechanisms of coordination among actors, (2) the distribution of coercive capacities and ruling power and (3) the forms of authority. Unintended consequences and collective problems are highlighted, in order to understand the current situation of insecurity in the area. 相似文献
926.
Local ownership as international governmentality: Evidence from the EU mission in the Horn of Africa
Filip Ejdus 《Contemporary Security Policy》2018,39(1):28-50
ABSTRACTWhile some Foucault-inspired studies construe local ownership in international interventions as a form of liberal governmentality that aims to govern through freedom, others lambast it as an illiberal governmentality that is likely to be resisted because it undermines local autonomy. However, we still do not know what is the rationality behind local ownership, how it is being operationalized, and why a principle that aims to govern through freedom ends up curtailing it. I argue that local ownership, echoing the colonial principle of indirect rule, is driven by the rationality of advanced democracies on how best to govern global insecurities at a distance. Consequently, ownership is operationalized as responsibilization for externally designed objectives. This often gives rise to local resistance which undermines international efforts to achieve ownership. I illustrate my arguments with evidence from the EU Mission on Regional Maritime Capacity Building in the Horn of Africa (EUCAP Nestor). 相似文献
927.
Michael Tkacik 《Defense & Security Analysis》2018,34(4):321-344
ABSTRACTThe slow moving conflict in the South China Sea has been characterized by some as “not worth the candle.” China claims the entirety of the South China Sea pursuant to a nine-dash line, the legal impact of which has been limited by international courts. At the same time, China has changed the reality of control over the South China Sea by building a number of fortified islands in the Spratly Islands and elsewhere. The US has either refused to stand up to China's behavior (Obama) or responded unevenly (Trump). This paper examines the impact of China's behaviour on local parties, US interests, and the liberal international system. 相似文献
928.
《防务技术》2020,16(1):96-106
The numerical simulation of a blast wave of a multilayer composite charge is investigated. A calculation model of the near-field explosion and far-field propagation of the shock wave of a composite charge is established using the AUTODYN finite element program. Results of the near-field and far-field calculations of the shock wave respectively converge at cell sizes of 0.25–0.5 cm and 1–3 cm. The Euler––flux-corrected transport solver is found to be suitable for the far-field calculation after mapping. A numerical simulation is conducted to study the formation, propagation, and interaction of the shock wave of the composite charge for different initiation modes. It is found that the initiation mode obviously affects the shock-wave waveform and pressure distribution of the composite charge. Additionally, it is found that the area of the overpressure distribution is greatest for internal and external simultaneous initiation, and the peak pressure of the shock wave exponentially decays, fitting the calculation formula of the peak overpressure attenuation under different initiation modes, which is obtained and verified by experiment. The difference between numerical and experimental results is less than 10%, and the peak overpressure of both internal and external initiation is 56.12% higher than that of central single-point initiation. 相似文献
929.
《防务技术》2020,16(5):969-979
Shock wave is emitted into the plate and sphere when a sphere hypervelocity impacts onto a thin plate. The fragmentation and phase change of the material caused by the propagation and unloading of shock wave could result in the formation of debris cloud eventually. Propagation models are deduced based on one-dimensional shock wave theory and the geometry of sphere, which uses elliptic equations (corresponding to ellipsoid equations in physical space) to describe the propagation of shock wave and the rarefaction wave. The “Effective thickness” is defined as the critical plate thickness that ensures the rarefaction wave overtake the shock wave at the back of the sphere. The “Effective thickness” is directly related to the form of the debris cloud. The relation of the “Effective thickness” and the “Optimum thickness” is also discussed. The impacts of Al spheres onto Al plates are simulated within SPH to verify the propagation models and associated theories. The results show that the wave fronts predicted by the propagation models are closer to the simulation result at higher impact velocity. The curvatures of the wave fronts decrease with the increase of impact velocities. The predicted “Effective thickness” is consistent with the simulation results. The analysis about the shock wave propagation and unloading in this paper can provide a new sight and inspiration for the quantitative study of hypervelocity impact and space debris protection. 相似文献
930.
胡新华 《兵团教育学院学报》2020,(3):61-64
中国现代文学史的教学应该有文献史料运用的意识,在文学作品解读的基础上充分利用教材中所列的文献史料,并认真查阅,从文学史现象的历史和文学史叙述本身的过程中掌握现代文学史的知识脉络。同时也需结合时代发展下教材的编写特点和学生学习的新习惯,在互联网教学平台上使用编写者提供的文献史料资源,多方面、多层次地进入到现代文学史的教学中。 相似文献