We study versions of cop and robber pursuit-evasion games on the visibility graphs of polygons, and inside polygons with straight and curved sides. Each player has full information about the other player’s location, players take turns, and the robber is captured when the cop arrives at the same point as the robber. In visibility graphs we show the cop can always win because visibility graphs ar...

We propose COP, a client-side system for protecting children’s online privacy and empowering parental control over children’s information disclosure with little manual effort. COP is compliant with the Children’s Online Privacy Protection Act (COPPA) and it implements acquisition of parental consent before any private information submitted online by children, e.g., registration to a Web service...

A cop wants to locate a robber hiding among the vertices of a graph. A round of the game consists of the robber moving to a neighbor of its current vertex (or not moving) and then the cop scanning some vertex to obtain the distance from that vertex to the robber. If the cop can at some point determine where the robber is, then the cop wins; otherwise, the robber wins. We prove that the robber w...

Static posturography provides an objective assessment of postural control by characterizing the body sway during upright standing. The center of pressure (COP) signal is recorded by a force platform, and it is analyzed by means of many different models and techniques. Most of the parameters calculated according to these different approaches are affected by relevant intra- and intersubject varia...

Vertex pursuit games are widely studied by both graph theorists and computer scientists. Cops and Robbers is a vertex pursuit game played on a graph, where some set of agents (or Cops) attempts to capture a robber. The cop number is the minimum number of cops needed to win. While cop number of a graph has been studied for over 25 years, it is not well understood, and has few connections with ex...

We consider the game of Cops and Robbers played on finite and countably infinite connected graphs. The length of games is considered on cop-win graphs, leading to a new parameter, the capture time of a graph. While the capture time of a cop-win graph on n vertices is bounded above by n−3, half the number of vertices is sufficient for a large class of graphs including chordal graphs. Examples ar...

Cop and robber is a two-player vertex-pursuit combinatorial game where the players stand on the vertices of a graph and alternate in moving to adjacent vertices. The cop wins when he captures the robber, robber’s goal is to avoid capture. The game has been studied in various modifications, many of which have an interesting relationship to certain well-known graph parameters, such as treewidth. ...

We address the problem of multi-objective constraint optimization problems (MO-COPs). Solving an MO-COP traditionally consists in computing the set of all Pareto solutions (i.e. the Pareto front). But this Pareto front is exponentially large in the general case. So this causes two main problems. First is the time complexity concerns. Second is a lack of decisiveness. In this paper, we present t...

Following a question of Anstee and Farber we investigate the possibility that all bridged graphs are cop-win. We show that in7nite chordal graphs, even of diameter two, need not be cop-win and point to some interesting questions, some of which we answer. c © 2002 Elsevier Science B.V. All rights reserved.

C monoxide poisoning (COP) is a common occurrence in today’s society, one of the most common poisonings worldwide, and is responsible for more fatalities than other toxic agent.1 Carbon monoxide has been termed the “silent killer” due its physical characters as well as its mechanism of action. It is generally accepted that, unintentional COP may be partially preventable through public education...