In order to meet the needs of high-speed development of optical communication system, a construction method of quasi-cyclic low-density parity-check(QC-LDPC) codes based on multiplicative group of finite field is prop...In order to meet the needs of high-speed development of optical communication system, a construction method of quasi-cyclic low-density parity-check(QC-LDPC) codes based on multiplicative group of finite field is proposed. The Tanner graph of parity check matrix of the code constructed by this method has no cycle of length 4, and it can make sure that the obtained code can get a good distance property. Simulation results show that when the bit error rate(BER) is 10-6, in the same simulation environment, the net coding gain(NCG) of the proposed QC-LDPC(3 780, 3 540) code with the code rate of 93.7% in this paper is improved by 2.18 dB and 1.6 dB respectively compared with those of the RS(255, 239) code in ITU-T G.975 and the LDPC(3 2640, 3 0592) code in ITU-T G.975.1. In addition, the NCG of the proposed QC-LDPC(3 780, 3 540) code is respectively 0.2 dB and 0.4 dB higher compared with those of the SG-QC-LDPC(3 780, 3 540) code based on the two different subgroups in finite field and the AS-QC-LDPC(3 780, 3 540) code based on the two arbitrary sets of a finite field. Thus, the proposed QC-LDPC(3 780, 3 540) code in this paper can be well applied in optical communication systems.展开更多
Since the paper of Box and Meyer who first considered the identification and estimation of dispersion effects from unreplicated factorial experiments,various different methods（both iterative and non-iterative） have ...Since the paper of Box and Meyer who first considered the identification and estimation of dispersion effects from unreplicated factorial experiments,various different methods（both iterative and non-iterative） have been proposed for estimating dispersion effects.An overview of various methods was given by Brenneman and Nair and they showed that the modified Harvey（MH） method is better than other methods.For a log-linear or multiplicative model,a non-iterative estimation method of dispersion effects based on residuals averaging from multiple location effect models is proposed in model selection stage,which has been shown smaller Mean Square Errors（MSE） than the MH method in majority of simulated models.And it can apply to the situations with zero or small absolute residuals,but the MH method will be failure.The properties of this estimator are also considered.A real example is used to illustrate the results.展开更多
This paper studies thee convergence properties of multiplicative iterative algorithms with inexact line search. We prove that the convergence can be guaranteed for a general form of line search rille, under the assu...This paper studies thee convergence properties of multiplicative iterative algorithms with inexact line search. We prove that the convergence can be guaranteed for a general form of line search rille, under the assumption of convexity of objective function or the assumption of convergence of the sequence generated by the algorithm. This answers an open problem put forward by lusem.展开更多
基金supported by the National Natural Science Foundation of China(No.61571072)the Basic and Advanced Technology Research Project in Chongqing(No.cstc2015jcyjA 40015)
文摘In order to meet the needs of high-speed development of optical communication system, a construction method of quasi-cyclic low-density parity-check(QC-LDPC) codes based on multiplicative group of finite field is proposed. The Tanner graph of parity check matrix of the code constructed by this method has no cycle of length 4, and it can make sure that the obtained code can get a good distance property. Simulation results show that when the bit error rate(BER) is 10-6, in the same simulation environment, the net coding gain(NCG) of the proposed QC-LDPC(3 780, 3 540) code with the code rate of 93.7% in this paper is improved by 2.18 dB and 1.6 dB respectively compared with those of the RS(255, 239) code in ITU-T G.975 and the LDPC(3 2640, 3 0592) code in ITU-T G.975.1. In addition, the NCG of the proposed QC-LDPC(3 780, 3 540) code is respectively 0.2 dB and 0.4 dB higher compared with those of the SG-QC-LDPC(3 780, 3 540) code based on the two different subgroups in finite field and the AS-QC-LDPC(3 780, 3 540) code based on the two arbitrary sets of a finite field. Thus, the proposed QC-LDPC(3 780, 3 540) code in this paper can be well applied in optical communication systems.
文摘Since the paper of Box and Meyer who first considered the identification and estimation of dispersion effects from unreplicated factorial experiments,various different methods（both iterative and non-iterative） have been proposed for estimating dispersion effects.An overview of various methods was given by Brenneman and Nair and they showed that the modified Harvey（MH） method is better than other methods.For a log-linear or multiplicative model,a non-iterative estimation method of dispersion effects based on residuals averaging from multiple location effect models is proposed in model selection stage,which has been shown smaller Mean Square Errors（MSE） than the MH method in majority of simulated models.And it can apply to the situations with zero or small absolute residuals,but the MH method will be failure.The properties of this estimator are also considered.A real example is used to illustrate the results.
文摘This paper studies thee convergence properties of multiplicative iterative algorithms with inexact line search. We prove that the convergence can be guaranteed for a general form of line search rille, under the assumption of convexity of objective function or the assumption of convergence of the sequence generated by the algorithm. This answers an open problem put forward by lusem.
