An eikonal equation based path planning method using polygon decomposition and curve evolution

Path planning is a key technique of autonomous navigation for robots, and the velocity field is an important part. Constructing velocity field in a complex workspace is still challenging. In this paper, an inner normal guided segmentation algorithm in a complex polygon is proposed to decompose the complex workspace in this paper. The artificial potential field model based on probability theory is then used to calculate the potential field of the decomposed workspace, and the velocity field is obtained by utilizing the potential field of this workspace. Path optimization is implemented by curve evolution, during which the internal force generated in the smoothing process of the initial path by a mean filter and the external force is obtained from the gradient of the workspace potential field. The parameter selection principle is deduced by analyzing the influence of several parameters on the path length and smoothness. Simulation results show that the designed polygon decomposition algorithm can effectively segment complex workspace and that the path optimization algorithm can shorten and smoothen paths.     

The struggle of a Kantian power in a Lockean world – German leadership in security and defence policy

ABSTRACT

German security and defence policy has undergone substantial transformation. This transformation requires an unprecedented level of political leadership, suggesting that Germany needs to solve the dilemma of how to supply leadership to increasingly demanding partners. What are the conditions under which German leadership can unfold in security and defence policy? To what degree do German role-conceptions of international agency and role-expectations of German leadership coincide? What kind of leadership outputs are produced? This study offers a comprehensive analysis of German security and defence policy in terms of supply (role conceptions) and demand (role expectations). We outline three leadership role conceptions present in the German strategic debate, which we then assess in the context of the Wendtian theory of cultures of anarchy. We then analyse Berlin's leadership in terms of outputs via the case study on Anchor Army and the Framework Nations Concept. We conclude that while Germany has tried to match leadership role expectations both rhetorically and in action, Berlin's leadership inputs have so far been insufficient. This has led to an imbalance in terms of role conceptions and expectations hampering effective German leadership in security and defence policy.     

对网络教学的几点思考

随着网络技术、多媒体技术的发展,网络教学已经成为一种重要的教学形式,如何正确把握网络教学的模式,抓住特点,准确定位教师在网络教学中的角色,上好每一堂课,应该是每一位老师考虑的问题。     

装备结构演化规律及重要度分析

以装备设计模块化的现状为依据,运用重要度理论,分析了装备结构演化及其重要度排序的规律。从单一部件逐步演化到5部件结构,以及N部件串并联结构,在此基础上,对演化规律进行了梳理,并对典型结构进行了重要度分析,得到了关于装备结构演化与各部件重要度排序规律,填补了对装备重要度漂移规律的研究空白,为装备可靠性优化设计提供了技术支撑。