134 research outputs found

    Ring Exploration with Oblivious Myopic Robots

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    The exploration problem in the discrete universe, using identical oblivious asynchronous robots without direct communication, has been well investigated. These robots have sensors that allow them to see their environment and move accordingly. However, the previous work on this problem assume that robots have an unlimited visibility, that is, they can see the position of all the other robots. In this paper, we consider deterministic exploration in an anonymous, unoriented ring using asynchronous, oblivious, and myopic robots. By myopic, we mean that the robots have only a limited visibility. We study the computational limits imposed by such robots and we show that under some conditions the exploration problem can still be solved. We study the cases where the robots visibility is limited to 1, 2, and 3 neighboring nodes, respectively.Comment: (2012

    Gathering on Rings for Myopic Asynchronous Robots With Lights

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    We investigate gathering algorithms for asynchronous autonomous mobile robots moving in uniform ring-shaped networks. Different from most work using the Look-Compute-Move (LCM) model, we assume that robots have limited visibility and lights. That is, robots can observe nodes only within a certain fixed distance, and emit a color from a set of constant number of colors. We consider gathering algorithms depending on two parameters related to the initial configuration: M_{init}, which denotes the number of nodes between two border nodes, and O_{init}, which denotes the number of nodes hosting robots between two border nodes. In both cases, a border node is a node hosting one or more robots that cannot see other robots on at least one side. Our main contribution is to prove that, if M_{init} or O_{init} is odd, gathering is always feasible with three or four colors. The proposed algorithms do not require additional assumptions, such as knowledge of the number of robots, multiplicity detection capabilities, or the assumption of towerless initial configurations. These results demonstrate the power of lights to achieve gathering of robots with limited visibility

    Computational Power of a Single Oblivious Mobile Agent in Two-Edge-Connected Graphs

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    Asynchronous Gathering in a Torus

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    We consider the gathering problem for asynchronous and oblivious robots that cannot communicate explicitly with each other but are endowed with visibility sensors that allow them to see the positions of the other robots. Most investigations on the gathering problem on the discrete universe are done on ring shaped networks due to the number of symmetric configurations. We extend in this paper the study of the gathering problem on torus shaped networks assuming robots endowed with local weak multiplicity detection. That is, robots cannot make the difference between nodes occupied by only one robot from those occupied by more than one robot unless it is their current node. Consequently, solutions based on creating a single multiplicity node as a landmark for the gathering cannot be used. We present in this paper a deterministic algorithm that solves the gathering problem starting from any rigid configuration on an asymmetric unoriented torus shaped network

    Rendezvous on a Known Dynamic Point on a Finite Unoriented Grid

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    In this paper, we have considered two fully synchronous OBLOT\mathcal{OBLOT} robots having no agreement on coordinates entering a finite unoriented grid through a door vertex at a corner, one by one. There is a resource that can move around the grid synchronously with the robots until it gets co-located along with at least one robot. Assuming the robots can see and identify the resource, we consider the problem where the robots must meet at the location of this dynamic resource within finite rounds. We name this problem "Rendezvous on a Known Dynamic Point". Here, we have provided an algorithm for the two robots to gather at the location of the dynamic resource. We have also provided a lower bound on time for this problem and showed that with certain assumption on the waiting time of the resource on a single vertex, the algorithm provided is time optimal. We have also shown that it is impossible to solve this problem if the scheduler considered is semi-synchronous

    Practical Considerations and Applications for Autonomous Robot Swarms

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    In recent years, the study of autonomous entities such as unmanned vehicles has begun to revolutionize both military and civilian devices. One important research focus of autonomous entities has been coordination problems for autonomous robot swarms. Traditionally, robot models are used for algorithms that account for the minimum specifications needed to operate the swarm. However, these theoretical models also gloss over important practical details. Some of these details, such as time, have been considered before (as epochs of execution). In this dissertation, we examine these details in the context of several problems and introduce new performance measures to capture practical details. Specifically, we introduce three new metrics: (1) the distance complexity (reflecting power usage and wear-and-tear of robots), (2) the spatial complexity (reflecting the space needed for the algorithm to work), and (3) local computational complexity (reflecting the computational requirements for each robot in the swarm). We apply these metrics in the study of some well-known and important problems, such as Complete Visibility and Arbitrary Pattern Formation. We also introduce and study a new problem, Doorway Egress, that captures the essence of a swarm’s navigation through restricted spaces. First, we examine the distance and spatial complexity used across a class of Complete Visibility algorithms. Second, we provide algorithms for Complete Visibility on an integer plane, including some that are asymptotically optimal in terms of time, distance complexity, and spatial complexity. Third, we introduce the problem of Doorway Egress and provide algorithms for a variety of robot swarm models with various optimalities. Finally, we provide an optimal algorithm for Arbitrary Pattern Formation on the grid

    For the Love of Robots: Posthumanism in Latin American Science Fiction Between 1960-1999

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    Posthumanism—understood as a symbiotic relationship between humans and technology—is quickly and surely becoming an inextricable part of daily life. In an era where technology can be worn as an extension of—and an enhancement to—our bodies, traditional science fiction tropes such as robots and cyborgs resurface and reformulate questions on critical aspects of human experience: who are we and what do our (imagined) technologies say about our world? Such questions are far more complex than they appear. Their answers should not come from one source alone, as humanness is experienced differently across time and cultural systems. In this sense, it is imperative to focus critical attention on works beyond the English-language canon in order to discover alternative readings of the posthuman, understand how varying historical, social, and economic contexts give new meanings to robots, cyborgs and hyper-technological imaginaries, and provide balancing perspectives to the ideas presented in canon posthuman science fiction from the developed world. To this end, this study centers on posthuman science fiction from Latin America. The primary works included here are limited only to Mexico, Chile, and Argentina—three of the countries with the greatest science fiction output in the region. This study explores the intersections of gender, sexualities, and posthumanism, as well as the underlying sociopolitical implications of such narratives. They exhibit an undeniable influence of canon Anglophone science fiction in terms of tropes (robots as mates for humans, cybernetic doppelgangers, technological utopias and dystopias) as well as problematic representations of gender, sex, and race. Yet, at the same time, posthuman elements in these Latin American narratives exhibit distinct local traits. Moreover, robot and cyborg figures enhance and renew discourses of political corruption, dictatorial trauma, surveillance, social and ecological decline. This study aims to outline the ways in which Latin American posthuman science fiction stands apart from the canon and proves itself as a legitimate genre. Simultaneously, this project seeks to supplement the nascent critical corpus on Latin American science fiction. It is my hope that this study’s insights will contribute to the field’s growth and success with scholars and readers alike
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