Genetic algorithm for short-term scheduling of make-and-pack batch production process

This paper considers a scheduling problem in industrial make-and-pack batch production process. This process equips with sequence-dependent changeover time, multipurpose storage units with limited capacity, storage time, batch splitting, partial equipment connectivity and transfer time. The objective is to make a production plan to satisfy all constraints while meeting demand requirement of packed products from various product families. This problem is NP-hard and the problem size is exponentially large for a realistic-sized problem. Therefore,we propose a genetic algorithm to handle this problem. Solutions to the problems are represented by chromosomes of product family sequences. These sequences are decoded to assign the resource for producing packed products according to forward assignment strategy and resource selection rules. These techniques greatly reduce unnecessary search space and improve search speed. In addition, design of experiment is carefully utilized to determine appropriate parameter settings. Ant colony optimization and Tabu search are also implemented for comparison. At the end of each heuristics, local search is applied for the packed product sequence to improve makespan. In an experimental analysis, all heuristics show the capability to solve large instances within reasonable computational time. In all problem instances, genetic algorithm averagely outperforms ant colony optimization and Tabu search with slightly longer computational time.

First Batch of Anhui Brandname Products Recommended by Anhui Provincial People's Government

Product NameMagang brand high quality carbon steel,common low carbon steel-made cold/hotrolling coil rod(without twisting control)Magang brand integral roll steel-madepassenger train wheel(φ915mm) forrailway useJingjing brand electrolytic

Pave the way to the batch production of SWNT arrays for carbonbased electronic devices

Single-walled carbon nanotubes(SWNTs)have been regarded as one of the most promising candidates to supplement or even replace silicon in the post-Moore era.The requirement is to prepare the horizontally aligned SWNTs arrays(HASAs)with multiple indicators,including high density,high semiconducting purity,and wafer-scale uniformity.However,after all the fevered works being done in controlled synthesis,we still have a long way to go before realizing the application of SWNTs in highly performed electronic devices.The methods of batch production and high-throughput characterization techniques of the HASAs are the two main challenges.In this outlook,we first summarized the progresses in synthesis of HASAs with either high density or high semiconducting purity.Then the methods adopted in characterizing SWNTs and HASAs were discussed according to the different principles of characterization techniques.Afterwards,the development of carbon nanotube based electronic devices,specifically,the field effect transistors(FETs),was reviewed from three perspectives.The problems involved in electronic applications bring forward the higher request to the HASAs itself.Therefore,in the end of this outlook,we prospected the future of the synthesis and corresponding characterization of HASAs,and tried to provide our ideas about how to pave the way to the batch production of HASAs for carbon based electronic devices.