Cooperative Pursuit with Multi-Pursuer and One Faster Free-moving Evader

This paper addresses a multi-pursuer single-evader pursuit-evasion game where the free-moving evader moves faster than the pursuers. Most of the existing works impose constraints on the faster evader such as limited moving area and moving direction. When the faster evader is allowed to move freely without any constraint, the main issues are how to form an encirclement to trap the evader into the capture domain, how to balance between forming an encirclement and approaching the faster evader, and what conditions make the capture possible. In this paper, a distributed pursuit algorithm is proposed to enable pursuers to form an encirclement and approach the faster evader. An algorithm that balances between forming an encirclement and approaching the faster evader is proposed. Moreover, sufficient capture conditions are derived based on the initial spatial distribution and the speed ratios of the pursuers and the evader. Simulation and experimental results on ground robots validate the effectiveness and practicability of the proposed method

Capturing an Evader Using Multiple Pursuers with Sensing Limitations in Convex Environment

A modified continuous-time pursuit-evasion game with multiple pursuers and a single evader is studied. The game has been played in an obstacle-free convex environment which consists an exit gate through which the evader may escape. The geometry of the convex is unknown to all players except pursuers know the location of the exit gate and they can communicate with each other. All players have equal maximum velocities and identical sensing range. An evader is navigating inside the environment and seeking the exit gate to win the game. A novel sweep-pursuit-capture strategy for the pursuers to search and capture the evader under some necessary and sufficient conditions is presented. We also show that three pursuers are sufficient to finish the operation successfully. Non-holonomic wheeled mobile robots of the same configurations have been used as the pursuers and the evader. Simulation studies demonstrate the performance of the proposed strategy in terms of interception time and the distance traveled by the players.

Synchronous intercept strategies for a robotic defense-intrusion game with two defenders

We study the defense-intrusion game, in which a single attacker robot tries to reach a stationary target that is protected by two defender robots. We focus on the "synchronous intercept problem", where both robots have to reach the attacker robot synchronously to intercept it. Assume that the attacker robot has the control policy which is based on attraction to the target and repulsion from the defenders, two kinds of synchronous intercept strategies are proposed for the defense-intrusion game, introduced here as Attacker-oriented and Neutral-position-oriented. Theoretical analysis and simulation results show that: (1) the two strategies are able to generate different synchronous intercept patterns: contact intercept pattern and stable non-contact intercept pattern, respectively. (2) The contact intercept pattern allows the defender robots to intercept the attacker robot in finite time, while the stable non-contact intercept pattern generates a periodic attractor that prevents the attack robot from reaching the target for infinite time. There is potential to apply the insights obtained into defense-intrusion in real systems, including aircraft escort and the defense of military targets or territorial boundaries

The Thought Remolding Campaign of the Chinese Communist Party-state

In its comprehensive analysis of a wide range of primary and secondary sources in both Chinese and Western languages, this authoritative work stands as the definitive study of the theory, implementation and legacy of the Chinese Communist Party's thought-remolding campaign. This decades-long campaign involved the extraction of confessions from millions of Chinese citizens suspected of heterodoxy or disobedience to party dictates, along with their subjection to various forms of "re-education" and indoctrination. Hu Ping's carefully structured overview provides a valuable insider's perspective, and supersedes the previous landmark study on this vastly interesting topic.Deze studie gaat in op de theorie, uitvoering en nalatenschap van de propagandacampagne van de Chinese Communistische Partij. Deze decennialange campagne bestond onder andere uit het ondervragen van miljoenen burgers die verdacht werden van andersdenkendheid of ongehoorzaamheid. Deze zorgvuldig gestructureerde verhandeling overstijgt de klassieke studie Thought Reform and the Psychology of Totalism (1969) van Robert jay Lifton. In tegenstelling tot het werk van Lifton, hanteert Hu Pings studie een eigentijds postcommunistisch perspectief en is het verrijkt met ervaringen van Chinezen die direct gevolgen hebben ondervonden van de maoïstische propagandacampagne

From Hospitality to Grace

The Pitt-Rivers Omnibus brings together the definitive essays and lectures of the influential social anthropologist Julian A. Pitt-Rivers, a corpus of work that has, until now, remained scattered, untranslated, and unedited. Illuminating the themes and topics that he engaged throughout his life—including hospitality, grace, the symbolic economy of reciprocity, kinship, the paradoxes of friendship, ritual logics, the anthropology of dress, and more—this omnibus brings his reflections to new life. Holding Pitt-Rivers’s diversity of subjects and ethnographic foci in the same gaze, this book reveals a theoretical unity that ran through his work and highlights his iconic wit and brilliance. Striking at the heart of anthropological theory, the pieces here explore the relationship between the mental and the material, between what is thought and what is done

Covid-19: Perspectives Across Africa

This book emanated from the Society for the Advancement of Science in Africa's (SASA) Seventh Annual International (digital) Conference: Joint SASA and Ugandan Ministry of Health October 15, 2020 – January 14, 2021, Kampala, Uganda. The chapters in this book were solicited from presenters and also from other authors familiar with the impact of Covid-19 in Africa. There are 21 chapters, all together offering a range of perspectives from a variety of angles.SASA (Society for the Advancement of Science in Africa