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1.
The problem of finding the expected shortest path in stochastic networks, where the presence of each node is probabilistic and the arc lengths are random variables, have numerous applications, especially in communication networks. The problem being NP-hard we use an ant colony system (ACS) to propose a metaheuristic algorithm for finding the expected shortest path. A new local heuristic is formulated for the proposed algorithm to consider the probabilistic nodes. The arc lengths are randomly generated based on the arc length distribution functions. Examples are worked out to illustrate the applicability of the proposed approach. 相似文献
2.
卷积码是一种重要的前向纠错信道编码方式,其纠错性能常常优于分组码,且(2,1,7)卷积码已应用于现代卫星通信系统中。Viterbi译码算法能最大限度地发挥卷积码的优异性能。这里采用Verilog HDL语言设计出(2,1,7)卷积码的编码器模块和基于Viterbi算法的译码器模块,译码器采用全并行结构,译码速度快。阐述了编译码器各模块的设计原理,并在ModelSim给出各模块的仿真测试结果。同时对译码器进行纠错性能测试,测试结果表明该Viterbi译码器有良好的纠错性能。 相似文献
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Jianbo Yang Yonggang Du Xiaoqian Liu 《Polymer-Plastics Technology and Engineering》2013,52(8):820-826
The nanocomposite of the Poly(vinyl chloride)/acrylonitrile-chlorinated- polyethylene-styrene (ACS)/methylacryloylpropyl-contaning polyhedral oligomeric silsesquioxane (MAP-POSS) (PVC/ACS/MAP-POSS) was prepared. Plasticizing behavior, dynamic rheology behavior and mechanical properties of the nanocomposites were investigated. The results showed that the plastic time decreased with increasing MAP-POSS content. The dynamic storage modulus G ′, loss modulus G″ and complex viscosity η* of the nanocomposites all exhibit a monotonic change with increasing frequency, and all have maximum when MAP-POSS content is 4 wt%, at the same frequency. The MAP-POSS can be used as an efficient process aid and impact aid of PVC/ACS blend at appropriate content. 相似文献
6.
介绍了WD-400A型电铲电气系统的特点,对系统速度与转矩特性进行了分析,并将交流变频调速电铲与直流调速电铲的性能进行了对比分析。 相似文献
7.
《Polymer-Plastics Technology and Engineering》2013,52(5):863-876
Graft-type ACS resin and α-methylstyrene (α-Mst)-containing ACS were synthesized by suspension polymerization. The effect of concentration of initiator and polyvinyl alcohol (PVA) on reaction was discussed. The graft efficiency (GE) increased with the increasing concentration of initiator in the first stage, but it began to decrease when the initiator concentration exceeded 3.3–3.5×10?4mol L?1. The GE decreased gradually with the increasing concentration of PVA. The rheological behavior, mechanical properties, and morphological structure of resins were studied. The rheological behavior became worse with the increasing content of chlorinated polyethylene and the melt is a pseudo-plastic liquid. The impact strength of graft-type ACS resin increased as the content of chlorinated polyethylene increased. The rheological behavior and impact properties of α-Mst-containing ACS resin got better because of the introduction of α-Mst, and the comprehensive properties was the best at the 5% α-Mst content of ACS resin. 相似文献
8.
针对应急救援车辆调度优化问题的特征和需求,以可变双向距离、道路风险和成本最小为主要目标,建立了应急救援车辆调度优化问题的多目标优化模型.为避免过早陷入局部最优,提出了基于混沌扰动的改进蚁群系统优化算法.该算法可对信息素进行全局更新混沌扰动,有效地提高了算法的适应性、求解效率和求解质量.仿真实验表明该算法是可行的,能较好地满足应急救援车辆调度的优化需求. 相似文献
9.
介绍了ACS800直接转矩控制变频器在3400/250三叠网多缸纸机负荷分配中的应用,就通讯、联锁、参数设置及使用中的注意事项等问题进行了讨论。 相似文献
10.
The industrially important yeast Candida utilis is widely used in production of food and medical materials, but its host-vector system has not been well developed. We screened for compact and efficient ARSs to construct practically useful vectors. The C. utilis strain AHU3053 was found to be efficiently transformed by the conventional lithium acetate method and was used as the host. The C. utilis IAM4264 genomic library was constructed by inserting the partial Sau3AI digests in pRI51, which has a kanMX gene expressible in C. utilis. By examining 98 C. utilis G418-resistant transformants, five plasmids had the highest ARS activity. By trimming of the inserts, the 1490 and 552 bp fragments with transformation activity of over 10(3)/microg DNA were obtained from ARS3 and ARS4, respectively. Although several sequences identical to S. cerevisiae ARS consensus sequences (ACSs) were found in ARS3 and ARS4, our deletion analysis indicated that these were not essential for the activity. Because the minimal functional ARS fragment was also several-fold larger than that of S. cerevisiae, the C. utilis ARSs have some unique characteristics resembling the Sz. pombe ARSs. These ARSs were functional in other C. utilis strains tested and useful for constructing practical vectors. 相似文献