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In this paper, we reÿne upper and lower bounds for the channel capacity of a serial, binary rewritable medium in which no consecutive locations may store 1's and no consecutive locations may be altered during a single rewriting pass. This problem was originally examined by Cohn (Discrete. Appl. Math. 56 (1995) 1) who proved that C, the channel capacity of(More)
This paper studies the algorithmic issues of the spanning star forest problem. We prove the following results: (1) There is a polynomial-time approximation scheme for planar graphs; (2) there is a polynomial-time 3 5-approximation algorithm for graphs; (3) it is NP-hard to approximate the problem within ratio 259 260 + for graphs; (4) there is a linear-time(More)
Role assignments, introduced by Everett and Borgatti [2], who called them role col-orings, formalize the idea, arising in the theory of social networks, that individuals of the same social role will relate in the same way to the individuals playing counterpart roles. If G is a graph, a k-role assignment is a function r mapping the vertex set onto the set of(More)
In this paper, we propose a deadlock-free routing in irregular networks using preex routing. Preex routing is a special type of routing with a compact routing table associated with each node (processor). Basically, each outgoing channel of a node is assigned a special label and an outgoing channel is selected if its label is a preex of the label of the(More)
—A shortest-path routing is optimal if it maximizes the probability of reaching the destination from a given source, assuming that each link in the system has a given failure probability. An approximation for the shortest-path routing policy, maximum-shortest-path (MSP) routing was proposed by Wu [3]. Reference [3] • shows that MSP is optimal in the mesh(More)
Accurate prediction of survival rates of cancer patients is often key to stratify patients for prognosis and treatment. Survival prediction is often accomplished by the TNM system that involves only three factors: tumor extent, lymph node involvement, and metastasis. This prediction from the TNM has been limited, because other potential prognostic factors(More)
This paper studies the algorithmic issues of the spanning star forest problem. We prove the following results: (1) there is a polynomial-time approximation scheme for planar unweighted graphs; (2) there is a polynomial-time algorithm with approximation ratio 3/5 for unweighted graphs; (3) it is NP-hard to approximate the problem within ratio 545/546 +(More)
A king u in a tournament is a player who beats any other player v directly or indirectly. That is, either u → v (u beats v) or there exists a third player w such that u → w and w → v. A sorted sequence of kings in a tournament of n players is a sequence of players, S = The existence of a sorted sequence of kings in any tournament is shown by Lou et al.(More)