Lauri Ahlroth

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In many complex computational processes one may want to store a sample of the process’ history for later use by placing checkpoints. In this paper we consider the problem of maintaining, in an online fashion, a collection of k checkpoints as an approximately uniformly spaced sample in the history of a continuous-time process. We present deterministic(More)
In many complex computational processes one may want to store a sample of the process’ history for later use by placing checkpoints. In this paper we consider the problem of maintaining, in an online fashion, a collection of k checkpoints as an approximately uniformly spaced sample in the history of a continuous-time process. We present deterministic(More)
We consider online bin packing where in addition to the opening cost of each bin, the arriving items collect delay costs until their assigned bins are released (closed), and the open bins themselves collect holding costs. Besides being of practical interest, this problem generalises several previously unrelated online optimisation problems. We provide a(More)
We consider two-player constraint satisfaction games on systems of Boolean constraints, in which the players take turns in selecting one of the available variables and setting it to true or false, with the goal of maximising (for Player I) or minimising (for Player II) the number of satisfied constraints. Unlike in standard QBF-type variable assignment(More)
In the problem of data aggregation in communication networks, messages arriving at the nodes of a network are to be forwarded to its root, with the option of being merged with other messages along their transmission path. The goal is to minimise, for a given message sequence, the total sum of the transmission link costs and the delay penalties the messages(More)
Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Lauri Ahlroth Name of the doctoral dissertation Online Algorithms in Resource Management and Constraint Satisfaction Publisher School of Science Unit Department of Information and Computer Science Series Aalto University publication series DOCTORAL DISSERTATIONS 133/2012 Field of research(More)
We consider online bin packing where in addition to the opening cost of each bin, the arriving items collect delay costs until their assigned bins are released (closed), and the open bins themselves collect holding costs. Besides being of practical interest, this problem generalises several previously unrelated online optimisation problems. We provide a(More)
Wepropose an online algorithm for an economic lot-sizing (ELS) problemwith lookahead, which achieves asymptotically optimal worst-case performance for increasing lookahead. Although intuitive, this result is interesting since deterministic algorithms for previously studied online ELS problems have unbounded competitive ratio. We also prove(More)