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261.
This article aims at formal specifications of reference systems in spatial cognition. It concentrates on two roles of reference systems connected to spatial language: reference systems resolving ambiguities and reference systems forming a basis for the classification of linguistic terms. Although coordinate systems are often seen as candidates for the geometric structure of reference systems, it is shown here that they do not appear in the explanations that go into the details. An analysis of the German terms vor, hinter, rechts and links (in front of, in back of, right, left) presents an alternative model for the geometric structure of spatial reference systems. 相似文献
262.
文章着重介绍了BZ9设备的自动控制软件的设计思想、方法,可视化高级语言Visual Basic 6.0的应用技巧和实践过程 相似文献
263.
关于外语专业数学教学的调查实践与思考 总被引:1,自引:1,他引:0
从当前高等教育研究中的学科交叉、文理渗透这一背景出发,介绍了对国内部分院校外语类专业数学教学情况的调查分析与作者在这方面的教学实践。针对人文专业数学教学的特点,就如何有效、合理地开展教学进行了思考。 相似文献
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结合星载合成孔径雷达(SAR)单视图像斑点噪声抑制技术与质量评估,并基于为科学数据可视化及数学分析提供完备计算环境的IDL(Interactive Data Language)语言,完成了在IDL环境下开发的SAR图像斑点抑制与质量评估系统,获得了高空间分辨率和高辐射分辨率的星载SAR图像. 相似文献
266.
灵巧壁面移动机器人运动学和动力学研究 总被引:3,自引:2,他引:1
灵巧壁面移动机器人是一个约束可变的系统,其可控性问题有待于证实.针对履带驱动方式具有非完整约束的性质,利用李群理论和微分几何的分析方法,对各种构型情况下灵巧壁面移动机器人运动学和动力学特性进行了研究,证明了灵巧壁面移动机器人的可控性,建立了机器人动力学方程,为机器人控制器的设计提供了理论指导. 相似文献
267.
《中国航空学报》2020,33(11):2946-2958
An impact-time-control guidance law is required for the simultaneous attack of suicide attack unmanned aerial vehicles. Based on the nonlinear model, a two-phase guidance strategy is proposed. The impact time is derived in a simple analytical form of initial states and switching states, and it can be controlled by switching at an appropriate range. Firstly, a two-phase guidance law is designed to make the magnitude of the heading error decrease monotonically from its initial value to zero. And then, the feasible interval of the switching ranges and of the impact times under the acceleration constraint are given analytically in sequence. Furthermore, a general form of two-phase guidance law is proposed, which allows the magnitude of the heading error to increase in the first phase, to improve the applicability of the methodology. Having the same structure as proportional navigation guidance with a time-varying gain, the proposed algorithms are simple and easy to implement. The corresponding feedback form is presented for realistic implementation. When a predefined impact time is taken within its permissible set, the constraints on the acceleration and field-of-view will not be violated during the interception. Finally, simulations validate the effectiveness of the methodology in impact time control and salvo attack. 相似文献
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An integrated cooperative guidance framework for multi-missile cooperatively attacking a single stationary target is proposed in this paper by combining both the centralized and decentralized communication topologies. Once missiles are distributed into several groups, missiles within a single group communicate with the centralized leader-follower framework, while the leaders from different groups communicate using the nearest-neighbor topology. To implement the integrated cooperative guidance framework, a group of Finite-Time Cooperative Guidance (FTCG) laws considering the saturation constraint on FOV (FTCG-FOV) are firstly derived within the centralized leader-follower framework to satisfy the communication topology of missiles in a single group. Then, an improved sequential approach is developed to adapt the FTCG-FOV to satisfy the communication topology between groups. The numerical simulations demonstrate the effectiveness and high efficiency of the integrated cooperative guidance framework and the cooperative guidance laws, as well as the superiority of the developed sequential approach. 相似文献