Generalized case-cohort design has been proved to be a cost-effective way to enhance the efficiency of large epidemiological cohort. In this article, we propose an inference procedure for estimating the unknown parame...Generalized case-cohort design has been proved to be a cost-effective way to enhance the efficiency of large epidemiological cohort. In this article, we propose an inference procedure for estimating the unknown parameters in Cox＇s proportional hazards model in generalized case-cohort design and establish an optimal sample size allocation to achieve the maximum power at a given budget. The finite sample performance of the proposed method is evaluated through simulation studies. The proposed method is applied to a real data set from the National Wilm＇s Tumor Study Group.展开更多
Coordinated multi-point transmission and reception （CoMP） for single user, named as SU-CoMP, is considered as an efficient approach to mitigate inter-cell interference in orthogonal frequency division multiple acce...Coordinated multi-point transmission and reception （CoMP） for single user, named as SU-CoMP, is considered as an efficient approach to mitigate inter-cell interference in orthogonal frequency division multiple access （OFDMA） systems. Two prevalent approaches in SU-CoMP are coordinated scheduling （CS） and joint processing （JP）. Although JP in SU-CoMP has been proved to achieve a great link performance improvement for the cell-edge user, efficient resource allocation （RA） on the system level is quite needed. However, so far limited work has been done considering JP, and most existing schemes achieved the improvement of cell-edge performance at cost of the cell-average performance degradation compared to the single cell RA. In this paper, a two-phase strategy is proposed for SU-CoMP networks. CS and JP are combined to improve both cell-edge and cell-average performance. Compared to the single cell RA, simulation results demonstrate that, the proposed strategy leads to both higher cell-average and cell-edge throughput.展开更多
The paper deals with the exponential stability problem of a variable coefficient star-shaped network,whose strings are coupled at a common end in a star-shaped configuration and the common connection of all strings ca...The paper deals with the exponential stability problem of a variable coefficient star-shaped network,whose strings are coupled at a common end in a star-shaped configuration and the common connection of all strings can be moved.Two kinds of media materials with a component of viscous and another simply elastic are distributed on each string.Under suitable hypothesis on the coefficient functionsμj(x)of damping terms and the kernelsηj(s)of distributed delay terms,the well-posedness of the system is obtained by means of resolvent family theory.In addition,the allocation proportion of the two parts and the property of the material character functions are discussed when the starshaped network is exponentially stable.Meanwhile,the sufficient condition of exponential stability is established.Numerical simulations are also included to verify the main results.展开更多
In this paper, we discuss quality of service requirements and impacts of different workloads of each service class on the resource proportion allocation scheme, and formulize the problem of minimizing the quality of s...In this paper, we discuss quality of service requirements and impacts of different workloads of each service class on the resource proportion allocation scheme, and formulize the problem of minimizing the quality of service miss rate of service requests by using the queuing theory. The optimally allocating resource proportion scheme is obtained by the Lagrangian optimization approach. Our simulation results show that our scheme is efficient.展开更多
基金Supported in part by the Central Universities under Grant No.31541311216,2042014kf0256the National Natural Science Foundation of China under Grant No.11171263,11301545,61371126 and 11401443
文摘Generalized case-cohort design has been proved to be a cost-effective way to enhance the efficiency of large epidemiological cohort. In this article, we propose an inference procedure for estimating the unknown parameters in Cox＇s proportional hazards model in generalized case-cohort design and establish an optimal sample size allocation to achieve the maximum power at a given budget. The finite sample performance of the proposed method is evaluated through simulation studies. The proposed method is applied to a real data set from the National Wilm＇s Tumor Study Group.
基金supported by the National Natural Science Foundation of China (61001116)State Emphasis Special Project 2009ZX03003-011-02+1 种基金the Hi-Tech Research and Development Program of China (2009AA011506)International Scientific and Technological Cooperation Program (2010DFA11060)
文摘Coordinated multi-point transmission and reception （CoMP） for single user, named as SU-CoMP, is considered as an efficient approach to mitigate inter-cell interference in orthogonal frequency division multiple access （OFDMA） systems. Two prevalent approaches in SU-CoMP are coordinated scheduling （CS） and joint processing （JP）. Although JP in SU-CoMP has been proved to achieve a great link performance improvement for the cell-edge user, efficient resource allocation （RA） on the system level is quite needed. However, so far limited work has been done considering JP, and most existing schemes achieved the improvement of cell-edge performance at cost of the cell-average performance degradation compared to the single cell RA. In this paper, a two-phase strategy is proposed for SU-CoMP networks. CS and JP are combined to improve both cell-edge and cell-average performance. Compared to the single cell RA, simulation results demonstrate that, the proposed strategy leads to both higher cell-average and cell-edge throughput.
基金the National Natural Science Foundation of China under Grant Nos.61773277 and 62073236。
文摘The paper deals with the exponential stability problem of a variable coefficient star-shaped network,whose strings are coupled at a common end in a star-shaped configuration and the common connection of all strings can be moved.Two kinds of media materials with a component of viscous and another simply elastic are distributed on each string.Under suitable hypothesis on the coefficient functionsμj(x)of damping terms and the kernelsηj(s)of distributed delay terms,the well-posedness of the system is obtained by means of resolvent family theory.In addition,the allocation proportion of the two parts and the property of the material character functions are discussed when the starshaped network is exponentially stable.Meanwhile,the sufficient condition of exponential stability is established.Numerical simulations are also included to verify the main results.
文摘In this paper, we discuss quality of service requirements and impacts of different workloads of each service class on the resource proportion allocation scheme, and formulize the problem of minimizing the quality of service miss rate of service requests by using the queuing theory. The optimally allocating resource proportion scheme is obtained by the Lagrangian optimization approach. Our simulation results show that our scheme is efficient.
