Panagiotis Voulgaris

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We present new faster algorithms for the exact solution of the shortest vector problem in arbitrary lattices. Our main result shows that the shortest vector in any <i>n</i>-dimensional lattice can be found in time 2<sup>3.199<i>n</i></sup> (and space 2<sup>1.325<i>n</i></sup>), or in space 2<sup>1.095<i>n</i></sup> (and still time 2<sup><i>O(n)</i></sup>).(More)
We give deterministic ~O(2<sup>2n+o(n)</sup>)-time algorithms to solve all the most important computational problems on point lattices in NP, including the Shortest Vector Problem (SVP), Closest Vector Problem (CVP), and Shortest Independent Vectors Problem (SIVP). This improves the n<sup>O(n)</sup> running time of the best previously known algorithms for(More)
Cryptosystems based on the hardness of lattice problems have recently acquired much importance due to their average-case to worst-case equivalence, their conjectured resistance to quantum cryptanalysis, their ease of implementation and increasing practicality, and, lately, their promising potential as a platform for constructing advanced functionalities. In(More)
The present work deals with the problem of information acquisition in a strategic networked environment. To study this problem, Kleinberg and Raghavan (FOCS 2005) introduced the model of <i>query incentive networks</i>, where the root of a binomial branching process wishes to retrieve an information -- known by each node independently with probability 1/n(More)
Cryptosystems based on the hardness of lattice problems have recently acquired much importance due to their average-case to worst-case equivalence, their conjectured resistance to quantum cryptanalysis, their ease of implementation and increasing practicality, and, lately, their promising potential as a platform for constructing advanced functionalities. In(More)
We give deterministic Õ(2)-time algorithms to solve all the most important computational problems on point lattices in NP, including the Shortest Vector Problem (SVP), Closest Vector Problem (CVP), and Shortest Independent Vectors Problem (SIVP). This improves the n running time of the best previously known algorithms for CVP (Kannan, Math. Operation(More)
Aggregation of entities is a widely observed phenomenon in economics, sociology, biology and other fields. It is natural to ask how diverse and competitive entities can achieve high levels of aggregation. In order to answer this question we provide a game-theoretical model for aggregation. We consider natural classes of strategies for the individuals and(More)
The aim of the present study was to determine the tolerance and efficacy of human brucellosis vaccine as well as the tolerance and sensitivity of the intradermal reaction test for brucellosis. A total of 1,121 subjects initially consented to participate in the study. Following clinical examination, 762 were tested with the intradermal reaction test (IDR(More)
Instant messengers (IMs) have become a very popular and convenient tool for communication. Having started with simple presence protocols, IMs now support exchange of text, sound, video, even game playing. Tons of information are being daily exchanged through IMs. Still, it seems that IMs favor functionality over security. Most popular IMs (MSN, Yahoo!(More)
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