To balance inventory cost with diverse demand,an optimal investment decision on necessary process improvement for delayed product differentiation is studied. A two-stage flexible manufacturing system is modeled as a c...To balance inventory cost with diverse demand,an optimal investment decision on necessary process improvement for delayed product differentiation is studied. A two-stage flexible manufacturing system is modeled as a continuous time Markov chain. The first production stage manufactures semifinished products based on a make-to-stock policy. The second production stage customizes semi-finished products from the first production stage on a make-to-order policy. Various performance measures for this flexible manufacturing system are evaluated by using matrix geometric methods. An optimization model to determine the level of investment on process improvement that minimizes the manufacturer ’s total cost is established. The results show that,a higher investment level can reduce both the expected customer order fulfillment delay and the expected semi-finished products inventory. When the initial order penetration point is 0. 4,the manufacturer ’s total cost is reduced by 15. 89% through process investment. In addition, the optimal investment level increases with the increase in the unit time cost of customer order fulfillment delay,and decreases with the increase in the product value and the initial order penetration point.展开更多
目的:通过CT三维重建对中国辽宁汉族成人下颌骨进行测量,分析不同垂直骨面型之间的差异。方法:使用VG Studio 2.2 MAX软件对106例(低角29例、均角47例、高角30例)辽宁汉族成人CT扫描数据进行三维颅骨提取,并在三维颅骨模型上测量下颌骨...目的:通过CT三维重建对中国辽宁汉族成人下颌骨进行测量,分析不同垂直骨面型之间的差异。方法:使用VG Studio 2.2 MAX软件对106例(低角29例、均角47例、高角30例)辽宁汉族成人CT扫描数据进行三维颅骨提取,并在三维颅骨模型上测量下颌骨的三维坐标;使用WinEDMA1.0.1软件对不同垂直骨面型成人的下颌骨做形状差异性分析并对差异进行bootstrap非参数检验。结果:欧几里得几何距离矩阵分析显示,辽宁不同垂直骨面型汉族成人的下颌骨按高角、均角、低角的顺序,下颌升支相对与整个下颌体由短变长,而下颌骨水平部的垂直高度由长变短。其主要差异集中在下颌骨升支,差异均有统计学意义。结论:辽宁地区不同垂直骨面型成人的下颌骨形态差异显著,在正畸治疗方案设计中应充分考虑该差异性。展开更多
A lot of work has been focused on desig-ning and analyzing various cooperative diversity pro-tocols for wireless relay networks. To provide a uni-fied queuing analytic framework, we fonmlate an em-bedded Markov chain,...A lot of work has been focused on desig-ning and analyzing various cooperative diversity pro-tocols for wireless relay networks. To provide a uni-fied queuing analytic framework, we fonmlate an em-bedded Markov chain, which rams out to be a Quasi-Birth-and-Death （QBD） process. Using the Matrix-Ce-ometric method, we can analyze the average delay in a unified way. Theoretical analysis is validated by simu-lation results. We show that the delay performances of Amplify-and-Forward or Decode-and-Forwaxd （AF/ DF） and incremental AF/DF schemes can be analyzed in the unified way. Thus, we can always choose the best cooperative diversity scheme in different scenari-os for delay minimization.展开更多
In this paper,a stepwise coupled-mode model with the use of the direct global matrix approach is proposed.This method is capable of handling two-dimensional problems with either a point source in cylindrical geometry ...In this paper,a stepwise coupled-mode model with the use of the direct global matrix approach is proposed.This method is capable of handling two-dimensional problems with either a point source in cylindrical geometry or a line source in plane geometry.With the use of the direct global matrix approach,this method is numerically stable.In addition,by introducing appropriately normalized range solutions,this model is free from the numerical overflow problem.Furthermore,we put forward source conditions appropriate for the line-source problem in plane geometry.As a result,this method is capable of addressing the scenario with a line source on top of a sloping bottom.Closed-form expressions for coupling matrices are derived and applied in this paper for handling problems with pressure-release boundaries and a homogeneous water column.The numerical simulations indicate that the proposed model is accurate,efficient,and numerically stable.Consequently,this model can serve as a benchmark model in range-dependent propagation modeling.Although this method is verified by an ideal wedge problem in this paper,the formulation applies to realistic problems as well.展开更多
基金The National Natural Science Foundation of China(No.71661147004)
文摘To balance inventory cost with diverse demand,an optimal investment decision on necessary process improvement for delayed product differentiation is studied. A two-stage flexible manufacturing system is modeled as a continuous time Markov chain. The first production stage manufactures semifinished products based on a make-to-stock policy. The second production stage customizes semi-finished products from the first production stage on a make-to-order policy. Various performance measures for this flexible manufacturing system are evaluated by using matrix geometric methods. An optimization model to determine the level of investment on process improvement that minimizes the manufacturer ’s total cost is established. The results show that,a higher investment level can reduce both the expected customer order fulfillment delay and the expected semi-finished products inventory. When the initial order penetration point is 0. 4,the manufacturer ’s total cost is reduced by 15. 89% through process investment. In addition, the optimal investment level increases with the increase in the unit time cost of customer order fulfillment delay,and decreases with the increase in the product value and the initial order penetration point.
文摘目的:通过CT三维重建对中国辽宁汉族成人下颌骨进行测量,分析不同垂直骨面型之间的差异。方法:使用VG Studio 2.2 MAX软件对106例(低角29例、均角47例、高角30例)辽宁汉族成人CT扫描数据进行三维颅骨提取,并在三维颅骨模型上测量下颌骨的三维坐标;使用WinEDMA1.0.1软件对不同垂直骨面型成人的下颌骨做形状差异性分析并对差异进行bootstrap非参数检验。结果:欧几里得几何距离矩阵分析显示,辽宁不同垂直骨面型汉族成人的下颌骨按高角、均角、低角的顺序,下颌升支相对与整个下颌体由短变长,而下颌骨水平部的垂直高度由长变短。其主要差异集中在下颌骨升支,差异均有统计学意义。结论:辽宁地区不同垂直骨面型成人的下颌骨形态差异显著,在正畸治疗方案设计中应充分考虑该差异性。
基金This work was supported by the National Basic Research Program of China under Crant No. 2012CB316001 the National Science Foundation of China under Crants No. （：13832008, No. 03902001.
文摘A lot of work has been focused on desig-ning and analyzing various cooperative diversity pro-tocols for wireless relay networks. To provide a uni-fied queuing analytic framework, we fonmlate an em-bedded Markov chain, which rams out to be a Quasi-Birth-and-Death （QBD） process. Using the Matrix-Ce-ometric method, we can analyze the average delay in a unified way. Theoretical analysis is validated by simu-lation results. We show that the delay performances of Amplify-and-Forward or Decode-and-Forwaxd （AF/ DF） and incremental AF/DF schemes can be analyzed in the unified way. Thus, we can always choose the best cooperative diversity scheme in different scenari-os for delay minimization.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10734100 and 11125420)the Knowledge Innovation Program of Chinese Academy of Sciences
文摘In this paper,a stepwise coupled-mode model with the use of the direct global matrix approach is proposed.This method is capable of handling two-dimensional problems with either a point source in cylindrical geometry or a line source in plane geometry.With the use of the direct global matrix approach,this method is numerically stable.In addition,by introducing appropriately normalized range solutions,this model is free from the numerical overflow problem.Furthermore,we put forward source conditions appropriate for the line-source problem in plane geometry.As a result,this method is capable of addressing the scenario with a line source on top of a sloping bottom.Closed-form expressions for coupling matrices are derived and applied in this paper for handling problems with pressure-release boundaries and a homogeneous water column.The numerical simulations indicate that the proposed model is accurate,efficient,and numerically stable.Consequently,this model can serve as a benchmark model in range-dependent propagation modeling.Although this method is verified by an ideal wedge problem in this paper,the formulation applies to realistic problems as well.
