Optimization of a multiple reservoir system operation using a combination of genetic algorithm and discrete differential dynamic programming: a case study in Mae Klong system, Thailand     

Janejira Tospornsampan  Ichiro Kita  Masayuki Ishii  Yoshinobu Kitamura 《Paddy and Water Environment》2005,3(1):29-38

A combination of genetic algorithm and discrete differential dynamic programming approach (called GA-DDDP) is proposed and developed to optimize the operation of the multiple reservoir system. The demonstration is carried out through application to the Mae Klong system in Thailand. The objective of optimization is to obtain the optimal operating policies by minimizing the total irrigation deficits during a critical drought year. The performance of the proposed algorithm is compared with the modified genetic algorithm. The results show that the proposed GA-DDDP provides optimal solutions, converging into the same fitness values within a short time. The GA is able to produce satisfactory results that are very close to those obtained from GA-DDDP but required alot more computation time to obtain the precise results. The difficulties in selecting optimal parameters of GA as well as finding a feasible initial trial trajectory of DDDP are significant problems and time-consuming. The significant advantage obtained from GA-DDDP is saving of computational resource as GA-DDDP requires no need for optimizing parameters and deriving feasible initial trial trajectories. Because DDDP is a part of GA-DDDP, the good performance of GA-DDDP is obtained when applied to a small system where numbers of discretizations and variables have no influence to the dimensionality problem of DDDP.  相似文献   

The effectiveness of evaluating wild species: searching for sources of resistance to bruchid beetles in the genus Vigna subgenus Ceratotropis   总被引：1，自引：0，他引：1  

Norihiko Tomooka  Kouichi Kashiwaba  Duncan A. Vaughan  Masao Ishimoto  Yoshinobu Egawa 《Euphytica》2000,115(1):27-41

A species level germplasm collection representing 76% of known taxa in the genus Vigna subgenus Ceratotropis was evaluated for resistance to two species of bruchid beetles, Callosobruchus chinensis and C. maculatus. Seven taxa consisting of 29 accessions were found to be resistant to C. chinensis and 4 taxa consisting of 24 accessions were found to be resistant to C. maculatus. This compared with no resistant accessions being found in several hundred landrace accessions of mungbean, V. radiata var. radiata, in the same subgenus. Sometimes resistance was found in all accessions of a particular taxon, such as complete resistance to both C. chinensis and C. macualtus in V. umbellata. Other taxa showed intra taxon variation for resistance such as V. reflexo-pilosa andV. minima. The levels and patterns of resistance among taxa were diverse. The results suggest that various factors cause resistance to bruchid in the subgenus Ceratotropis. While the number of eggs laid on seeds generally reflected seed size, one small seeded cultivar of V. mungo var. mungo, black gram, had an unusually high number of eggs laid per seed. No correlation was found between seed size and levels of resistance. The species level germplasm collection, which reflects the core collection concept in trying to maximize genetic diversity in a limited number of accessions, has enabled a large number of potentially useful sources of resistance to bruchid beetles to be found efficiently. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Evaluation of rolling shear strength of plywood by flexural vibration method     

Heng Xu  Chiaki Tanaka  Tetsuya Nakao  Masahiro Yoshinobu  Hiroyuki Katayama 《Journal of Wood Science》1998,44(2):147-151

The rolling shear strength of plywood was evaluated using a flexural vibration test. Test specimens were lauan and Douglas fir three-ply plywoods made from thick veneers. The dynamic shear and Young's moduli were determined using the flexural vibration method, which involved in-plane and out-of-plane flexural vibration. The rolling shear strength was determined using the static destructive method, which is dependent on the direction of the lathe check in the core veneer. Before and after accelerated aging treatments were conducted, there were relations between out-of-plane dynamic properties (out-of-plane shear and Young's moduli) and its rolling shear strength. It was concluded that the rolling shear strength is related not only to the shear property of the core but the flexural stiffness of two faces when the deformation of out-of-plane plywood was not restrained.Part of this work was presented at the 47th Annual Meeting of The Japan Wood Research Society, Kochi, April 1997  相似文献