Decision-based genetic algorithms for solving multi-period project scheduling with dynamically experienced workforce

The importance of the flexibility of resources increased rapidly with the turbulent changes in the industrial context, to meet the customers’ requirements. Among all resources, the most important and considered as the hardest to manage are human resources, in reasons of availability and/or conventions. In this article, we present an approach to solve project scheduling with multi-period human resources allocation taking into account two flexibility levers. The first is the annual hours and working time regulation, and the second is the actors’ multi-skills. The productivity of each operator was considered as dynamic, developing or degrading depending on the prior allocation decisions. The solving approach mainly uses decision-based genetic algorithms, in which, chromosomes don’t represent directly the problem solution; they simply present three decisions: tasks’ priorities for execution, actors’ priorities for carrying out these tasks, and finally the priority of working time strategy that can be considered during the specified working period. Also the principle of critical skill was taken into account. Based on these decisions and during a serial scheduling generating scheme, one can in a sequential manner introduce the project scheduling and the corresponding workforce allocations

ACC Synthase Genes Related to Cold-dependent Ripening in Pear Fruit

The differential regulation of ACC synthase genes has been studied in pear cultivars that either require a long chilling treatment before they are capable of ripening (‘Passe-Crassane’, PC) or not (‘Old-Home’, OH) and in OH x PC hybrids having no (A16) or intermediate (A50) cold requirement. Among the seven Pc-ACS cDNAs isolated, four of them (Pc-ACS1a/b and Pc-ACS2a/b) showed differential expression in relation with cold requirement. Pc-ACS1a transcripts accumulated specifically during chilling and ripening of cold-dependent cultivars while Pc-ACS1b transcripts were detected only during ripening of cold-independent genotypes. Pc- ACS2a mRNA was expressed specifically in cold-dependent genotypes and negatively regulated by ethylene while Pc-ACS2b transcripts accumulated only in cold-independent genotypes and positively regulated by ethylene. Pc-ACS3, 4 and 5 transcripts accumulation was similar in all genotypes, independently of coldrequirements