We consider a Cops-and-Robber game played on the subsets of an n-set. The robber starts at the full set; the cops start at the empty set. In each round, each cop moves up one level by gaining an element, and the robber moves down one level by discarding an element. The question is how many cops are needed to ensure catching the robber when the robber reaches the middle level. Alan Hill posed th...

Symbiotic computing leads to a proliferation of computing devices that allow linking people, favoring the development of distributed Communities of Practice (CoPs). Their members, being dispersed geographically, have to rely strongly on technological means to interact. In this context, coordinating distributed CoPs is more challenging than coordinating their collocated counterparts. Hence, the ...

The purpose of this study is to introduce CoP reward allocation (COREA) system that efficiently solves a mathematical optimization problem to optimally allocate limited financial reward and to promote knowledge sharing activities in CoPs. To test the validity and usefulness of COREA, we simulate three knowledge sharing climates in which the majority of CoPs performs below-, on-, or above-averag...

Tabu Search (TS) is a meta-heuristic search algorithm that is easy to parallelise. E cient parallelisation of TS can represent a signi cant saving in the real-time required to solve a problem over an equivalent sequential algorithm. In this study, a general parallel TS algorithm for solving combinatorial optimisation problems (COPs) is presented. The unique feature of our approach is that the T...

Delayed neurologic deficits, paraplegia and paraparesis, are devastating complications after repair of a descending thoracic and thoracoabdominal aortic aneurysm (TAAA). A treatment protocol has not been established, although strategies such as cerebrospinal fluid (CSF) drainage, maintaining blood pressure and medication have been described. Cerebrospinal drain status /oxygen delivery/patient s...

Non-typhoidal Salmonella (NTS) serovars S. Enteritidis and S. Typhimurium are a major cause of invasive bacterial disease (e.g., bacteremia, meningitis) in infants and young children in sub-Saharan Africa and also occasionally cause invasive disease in highly susceptible hosts (young infants, the elderly, and immunocompromised subjects) in industrialized countries. No licensed vaccines exist ag...

The objective of information system security management is information assurance: to maintain confidentiality (privacy), integrity, and availability of information resources for authorized organizational end users. User authentication is a foundation procedure in the overall pursuit of these objectives, and password procedures have historically been the primary method of user authentication. Th...

In the game of Cops and Robbers, a team of cops attempts to capture a robber on a graph G. All players occupy vertices of G. The game operates in rounds; in each round the cops move to neighboring vertices, after which the robber does the same. The minimum number of cops needed to guarantee capture of a robber on G is the cop number of G, denoted c(G), and the minimum number of rounds needed fo...

Convinced by the important role of CoPs (communities of practice) and the innovative learning modality they offer, the École Polytechnique Fédérale de Lausanne is currently developing a framework to sustain interaction, collaboration, and learning in laboratory-oriented CoPs, namely the eLogBook. This paper describes the services provided by this framework, the 3A model on which it is based, an...

We study graph searching games where a number of cops try to capture a robber that is hiding in a system of tunnels modelled as a graph. While the current position of the robber is unknown to the cops, each cop can see a certain radius d around his position. For the case d = 1 these games have been studied by Fomin, Kratsch and Müller [7] under the name domination games. We are primarily intere...