The MAC layer of the 802.11 standard, based on the CSMA/CA mechanism, specifies a set of parameters to control the aggressiveness of stations when trying to access the channel. However, these parameters are statically set independently of the conditions of the WLAN (e.g. the number of contending stations), leading to poor performance for most scenarios. To overcome this limitation previous work...

A multi-heuristic schedule repair model for schedule conflict resolution is presented and its application in repairing the schedules of a prefabrication plant is described in this paper. The model combines heuristic strategies with Genetic Algorithms to repair schedules with resource constraints. The GA determines the “best” sequence of resolving schedule disturbances using heuristic rules sele...

Given a set of timetabled tasks, the multi-depot vehicle scheduling problem is a well-known problem that consists of determining least-cost schedules for vehicles assigned to several depots such that each task is accomplished exactly once by a vehicle. In this paper, we propose to compare the performance of five different heuristic approaches for this problem, namely, a heuristic mip solver, a ...

This paper describes our participation in the Task understanding task of the Tasks track at TREC 2016. We introduce a general probabilistic framework in which we combine query suggestions from web search engines with keyphrases generated from top ranked documents. We achieved top performance among all submitted systems, on both official evaluation metrics, which attests the effectiveness of our...

We propose a structure-exploiting heuristic for the justification-based stochastic local search (SLS) method CRSat for Boolean circuit satisfiability. Experimental evaluation shows that the proposed depth-based heuristic significantly improved the performance of CRSat on structural instances arising from industrial applications. A proof of probabilistically approximate completeness (PAC) of CRS...

The paper is concerned with the computational evaluation of a new branching heuristic, called reverse assignment sequence (RAS), for evolved DPLL Satisfiability solvers. Such heuristic, like several other recent ones, is based on the history of the conflicts obtained during the solution of an instance. A score is associated to each literal. When a conflict occurs, some scores are incremented wi...

During the recent Dialog State Tracking Challenge (DSTC), a fundamental question was raised: “Would better performance in dialog state tracking translate to better performance of the optimized policy by reinforcement learning?” Also, during the challenge system evaluation, another nontrivial question arose: “Which evaluation metric and schedule would best predict improvement in overall dialog p...