Groupware systems are computer based systems which supports two or more users working in a tightly coupled fashion on a common task. This paper briefly introduc ess a family of concurrency control algorithms for groupware systems. These algo rithms maintain consistency without locking, and without rollback, within a dynam ic non-serializable environment. A consistency theorem for this family of...

Editors Frances Rosamond (Univ Bergen) [email protected] and Valia Mitsou (Univ Paris Diderot) [email protected]. Congratulations to all for many awards and prizes, graduates, new jobs, and wonderful research. ALGO 2017 showcased ten awards and 8 of them were related to parameterized complexity! This newsletter includes articles by the IPEC Best Paper and Excellent Student Paper Award...

Known results: • Generalizes Set Cover, (Non-Metric / Multi-level) Facility Location, Group Steiner Tree • Ω(log2− n)-hard (Halperin, Krauthgamer ’03) • |X| -apx in poly by sophisticated greedy algo (Zelikovsky ’97) • O(log |X|)-apx in nO(log |X|) time by more sophisticated greedy algo (Charikar, Chekuri, Cheung, Goel, Guha and Li ’99) • LP’s have integrality gap Ω( √ k) already for 5 layers; e...

Recently a model for supervised learning of probabilistic transduc ers represented by su x trees was introduced However this algo rithm tends to build very large trees requiring very large amounts of computer memory In this paper we propose a new more com pact transducer model in which one shares the parameters of distri butions associated to contexts yielding similar conditional output distrib...