针对一类考虑返修和产品多态性的多级串联制造系统性能分析问题,在考虑系统设备故障基础上,重点研究产品的返修和报废以及产品的多态性导致工位正常运行时加工状态差异对系统性能的影响,提出一种基于扩展Petri网(Extended-stochastic Pe...针对一类考虑返修和产品多态性的多级串联制造系统性能分析问题,在考虑系统设备故障基础上,重点研究产品的返修和报废以及产品的多态性导致工位正常运行时加工状态差异对系统性能的影响,提出一种基于扩展Petri网(Extended-stochastic Petri nets,ESPN)的系统模块化建模方法,解决传统利用Markov模型和排队网络模型建模难以清晰描述系统内部产品流转换导致复杂状态变化的问题。将ESPN模型同构于嵌入Markov链得到工位状态空间,推导产品多态性导致的工位不同加工状态相对激发概率分布。以双工位单缓冲区的两级串联制造系统单元模型性能分析为基础,考虑缓冲区两边系统对单元模型的影响,基于重叠分解法对系统模型进行迭代求解,分析系统各项性能指标。某企业汽车动力总成装配线的实例验证了该建模与分析方法的有效性。展开更多
The main purpose of this study was to detect an association of cytoplasmic signal transducers and activators of transcription-1 （STAT1） with milk production traits in 472 Holstein and 283 Jersey cattle breeds of Tur...The main purpose of this study was to detect an association of cytoplasmic signal transducers and activators of transcription-1 （STAT1） with milk production traits in 472 Holstein and 283 Jersey cattle breeds of Turkey. This gene, located on chromosome 2, was chosen due to its role on development of mammary gland. A polymorphism of selected 314 bp allele fragment was detected by the restriction fragment length polymorphism analysis of polymerase chain reaction-amplified fragments （PCR-RFLP） method and also confirmed by DNA sequencing. The association tests were conducted between STAT1 genotypes and some economically important dairy traits. The genotypes for C/T as a single nucleotide polymorphism （SNP） were identified at interval 60 cM to 63 cM. The effects of STAT1 gene on milk production traits were not significant in Holstein cows, although animals with CT genotypes showed fairly close to significant value for the corrected 305 d milk yield. However, Jersey cows with/7＂ genotype were 2.07 kg higher for test-day milk yield （P 〈 0.05）, 0.13 kg for fat yield （P 〈 0.01） and 0.07 kg for protein yield （P 〈 0.05） compared with animals having CC and CT genotypes. Definitely, the further research should be conducted to search this gene intensively with larger samples to identify polymorphism and any association between the economically important traits and genotypic class in Holstein cows. Finally, based on the findings, it was concluded that STATI gene might be used as a potential candidate gene to improve milk yield and milk fat and protein contents in dairy cows breeding programs.展开更多
文摘针对一类考虑返修和产品多态性的多级串联制造系统性能分析问题,在考虑系统设备故障基础上,重点研究产品的返修和报废以及产品的多态性导致工位正常运行时加工状态差异对系统性能的影响,提出一种基于扩展Petri网(Extended-stochastic Petri nets,ESPN)的系统模块化建模方法,解决传统利用Markov模型和排队网络模型建模难以清晰描述系统内部产品流转换导致复杂状态变化的问题。将ESPN模型同构于嵌入Markov链得到工位状态空间,推导产品多态性导致的工位不同加工状态相对激发概率分布。以双工位单缓冲区的两级串联制造系统单元模型性能分析为基础,考虑缓冲区两边系统对单元模型的影响,基于重叠分解法对系统模型进行迭代求解,分析系统各项性能指标。某企业汽车动力总成装配线的实例验证了该建模与分析方法的有效性。
文摘The main purpose of this study was to detect an association of cytoplasmic signal transducers and activators of transcription-1 （STAT1） with milk production traits in 472 Holstein and 283 Jersey cattle breeds of Turkey. This gene, located on chromosome 2, was chosen due to its role on development of mammary gland. A polymorphism of selected 314 bp allele fragment was detected by the restriction fragment length polymorphism analysis of polymerase chain reaction-amplified fragments （PCR-RFLP） method and also confirmed by DNA sequencing. The association tests were conducted between STAT1 genotypes and some economically important dairy traits. The genotypes for C/T as a single nucleotide polymorphism （SNP） were identified at interval 60 cM to 63 cM. The effects of STAT1 gene on milk production traits were not significant in Holstein cows, although animals with CT genotypes showed fairly close to significant value for the corrected 305 d milk yield. However, Jersey cows with/7＂ genotype were 2.07 kg higher for test-day milk yield （P 〈 0.05）, 0.13 kg for fat yield （P 〈 0.01） and 0.07 kg for protein yield （P 〈 0.05） compared with animals having CC and CT genotypes. Definitely, the further research should be conducted to search this gene intensively with larger samples to identify polymorphism and any association between the economically important traits and genotypic class in Holstein cows. Finally, based on the findings, it was concluded that STATI gene might be used as a potential candidate gene to improve milk yield and milk fat and protein contents in dairy cows breeding programs.
