2,819 research outputs found
A biased random-key genetic algorithm with forward-backward improvement for the resource constrained project scheduling problem
This paper presents a biased random-key genetic algorithm for the resource constrained project scheduling problem. The chromosome representation of the problem is based on random keys. Active schedules are constructed using a priority-rule heuristic in which the priorities of the activities are defined by the genetic algorithm. A forward-backward improvement procedure is applied to all solutions. The chromosomes supplied by the genetic algorithm are adjusted to reflect the solutions obtained by the improvement procedure. The heuristic is tested on a set of standard problems taken from the literature and compared with other approaches. The computational results validate the effectiveness of the proposed algorithm
A random key based genetic algorithm for the resource constrained project scheduling problem
This paper presents a genetic algorithm for the Resource Constrained Project Scheduling Problem (RCPSP). The chromosome representation of the problem is based on random keys. The schedule is constructed using a heuristic priority rule in which the priorities of the activities are defined by the genetic algorithm. The heuristic generates parameterized active schedules. The approach was tested on a set of standard problems taken from the literature and compared with other approaches. The computational results validate the effectiveness of the proposed algorithm
Ventilação não invasiva com pressão positiva intermitente - experiência de 7 anos
Introduction: Nasal intermittent positive pressure ventilation (NIPPV) is a non invasive ventilation method that combines the benefits of nasal continuous positive airway pressure (NCPAP) and the cycles of positive pressure.
Objectives: Description of the NIPPV experience in a neonatal intensive care unit.
Methods: A descriptive study of newborns ventilated with NIPPV, from January 2002 to December 2008. Were considered two groups: the first group had mechanical ventilation before NIPPV, and in the second group the initial method was non-invasive ventilation. These 2 groups were subdivided: Group 1: sub-group A, NIPPV immediately after weaning and sub- group B, NIPPV after mechanical ventilation followed by NCPAP. The group 2 was sub-divided in sub-group C, NIPPV after NCPAP, and sub-group D, NIPPV as the initial mode of ventilation.
Results: In group 1 we analysed 79 cycles of ventilation with 89% of success and in group 2 55 cycles, with 69% of success. Newborns in group 1 had a median weight of 925g and gestational age of 27 weeks and the group 2 had 1350g and 30 weeks, respectively.
Conclusions: NIPPV was used mainly after conventional ventilation in lighter and immature babies, without relevant complications
Variability of the anthracnose fungus Colletotrichum graminicola in sorghum genotype mixtures.
This paper reports partial results obtained on the variability of Colletotrichum graminicola developed in response to the host diversity generated by three-line combination of sorghum (Sorghum bicolor) genotypes. Nine sorghum lines were used in this study: CMSXS210B, CMSXS112B, CMSXS215B, CMSXS221B, CMSXS169R, CMSXS180R, CMSXS182R, CMSXS227R, and CMSXS116R. A total of 39 treatments on mixtures and pure stands of the component lines were evaluated in the field for the development of anthracnose, as a natural epidemic. Samples of the single spore isolates of the pathogen of each treatment indicated a reduction in the phenotypic diversity and an increase in the frequency of more complex races in genotype mixturesin relation to the pure stands of each genotype. O presente trabalho relata resultados parciais sobre a variabilidade de Colletotrichum graminicola, agente causal da antracnose do sorgo (Sorghum bicolor), desenvolvida em resposta à diversidade gerada na população hospedeira através de misturas formadas pela combinação, três a três, de diferentes linhagens de sorgo. Nove linhagens foram utilizadas neste estudo: CMSXS210B, CMSXS112B, CMSXS215B, CMSXS221B, CMSXS169R,CMSXS180R, CMSXS182R, CMSXS227R, and CMSXS116R. Misturas e estandes puros de cada linhagem componente, em um total de 39 tratamentos, foram avaliados no campo, para o desenvolvimento da antracnose em condições de infecção natural. Amostras de isolados monospóricos do patógeno obtidas de cada tratamento indicaram uma redução na diversidade fenotÃpica do patógeno e um aumento na freqüência de raças de maior complexidade em todas as misturas em relação aos estandes puros de cada genótipo
Variabilidade em Colletotrichum graminicola, agente causal da antracnose, em misturas de genótipos de sorgo.
EVOLUTIONARY ALGORITHMS FOR OVERLAPPING CORRELATION CLUSTERING
Abstract. In Overlapping Correlation Clustering (OCC), a number of objects are assigned to clusters. Two objects in the same cluster have correlated characteristics. As opposed to traditional clustering where objects are assigned to a single cluster, in OCC objects may be assigned to one or more clusters. since an object can have characteristics that are correlated with objects in more than one cluster. In this paper, we present Biased Random-Key Genetic Algorithms for OCC. Computational experiments are presented. 1
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