The design of a fast double-channel multi-channel scaler system is described. Its dead time between channels is zero. This system has a adjustable dwell time between 1 ms/channel and 1000s/channel. Data acquisited and...The design of a fast double-channel multi-channel scaler system is described. Its dead time between channels is zero. This system has a adjustable dwell time between 1 ms/channel and 1000s/channel. Data acquisited and orders is sent to the portable computer through print parallel port.展开更多
In this paper, we study the rank of matrices over GF(2~p),and propose two construction methods for algebraic-based nonbinary LDPC codes from an existing LDPC code, referred to as the original code. By multiplying all ...In this paper, we study the rank of matrices over GF(2~p),and propose two construction methods for algebraic-based nonbinary LDPC codes from an existing LDPC code, referred to as the original code. By multiplying all elements of each column of the binary parity-check matrix H corresponding to the original code with the same nonzero element of any field, the first class of nonbinary LDPC codes with flexible field order is proposed. The second method is to replace the nonzero elements of some columns in H with different nonzero field elements in a given field, and then another class of nonbinary LDPC codes with various rates is obtained. Simulation results show that the proposed nonbinary LDPC codes perform well over the AWGN channel with the iterative decoding algorithms.展开更多
A household survey was carried out in Central Malawi to evaluate the goat marketing structure and systems in the rural areas using Nsundwe and Nkhoma areas in Lilongwe District as a case study. The analysis focused on...A household survey was carried out in Central Malawi to evaluate the goat marketing structure and systems in the rural areas using Nsundwe and Nkhoma areas in Lilongwe District as a case study. The analysis focused on identifying marketing systems of goats in Malawi by investigating the role of goats in an average Malawian rural household and how the current goat marketing systems affects that role. Goats play important role in Malawian rural households by way of providing food, income and as a capital reserve to be used in times critical times of food scarcity. The findings indicate that there is potential for goats to generate more income for the rural farmers, which can in turn help to improve household food security. The marketing system however apparently does not favour the farmers. The farmers seem not to know goat prices beyond the rural markets and hence have inadequate negotiating power to sell at optimum prices. Middlemen bought from farmers and finally sold the goats to urban consumers and retail shops. From the analysis, middlemen seemed to control the goat marketing system. Urban butchers sold the goats at 58% more than the value of farmers while retail shops sold at 137% more than the value of farmers. The differences reflect value-adding activities done at butchers and retail shops levels as well as transportation costs and profit margins. Though farmers may not engage in value adding, the finding implies that they would fetch more money if they supplied directly to the retail shops than to the middlemen. With access to more market information, they could also increase their bargaining power information with middlemen and sell the goats at relatively higher prices than the current. This paper details the results of the study.展开更多
Manufacturers’channel competition with service is examined in this paper.Specifically,the authors consider channel competition within a supply chain comprising two manufacturers and one single retailer where each man...Manufacturers’channel competition with service is examined in this paper.Specifically,the authors consider channel competition within a supply chain comprising two manufacturers and one single retailer where each manufacturer can choose to sell its products either directly to the end market(online channel,say)or through the potential retail channel,based on the profit maximization criterion,which is influenced by exogenous market conditions,such as the degree of competition,etc.Furthermore,the retailer provides additional demand-enhancing service to promote the manufacturer’s products distributed via it.If only one of the manufacturers sells products through the retailer,its products will be promoted by the additional retail service,which poaches demand of products of the manufacturer who adopts direct online channel.Products of both manufacturers are supported by the retailer’s promotional service when both distribute their product through the common retailer.Finally,some managerial implications are derived from numerical analyses of our model,which explain the phenomena in practice and conclude the paper.展开更多
The outage performance of the multihop free-space optical(FSO) communication system with decode-and-forward(DF) protocol is studied by considering the joint effects of nonzero boresight pointing errors and atmospheric...The outage performance of the multihop free-space optical(FSO) communication system with decode-and-forward(DF) protocol is studied by considering the joint effects of nonzero boresight pointing errors and atmospheric turbulence modeled by exponentiated Weibull(EW) distribution. The closed-form analytical expression of outage probability is derived, and the results are validated through Monte Carlo simulation. Furthermore, the detailed analysis is provided to evaluate the impacts of turbulence strength, receiver aperture size, boresight displacement, beamwidth and number of relays on the outage performance for the studied system.展开更多
文摘The design of a fast double-channel multi-channel scaler system is described. Its dead time between channels is zero. This system has a adjustable dwell time between 1 ms/channel and 1000s/channel. Data acquisited and orders is sent to the portable computer through print parallel port.
基金supported in part by National Basic Research Program of China under Grant No.2012CB316100National Natural Science Foundation of China under Grants 61372074 and 91438101+1 种基金Joint Funds of the National Natural Science Foundation of China under Grant No.U1504601Science and Technology on Communication Networks Laboratory under Grant KX132600032
文摘In this paper, we study the rank of matrices over GF(2~p),and propose two construction methods for algebraic-based nonbinary LDPC codes from an existing LDPC code, referred to as the original code. By multiplying all elements of each column of the binary parity-check matrix H corresponding to the original code with the same nonzero element of any field, the first class of nonbinary LDPC codes with flexible field order is proposed. The second method is to replace the nonzero elements of some columns in H with different nonzero field elements in a given field, and then another class of nonbinary LDPC codes with various rates is obtained. Simulation results show that the proposed nonbinary LDPC codes perform well over the AWGN channel with the iterative decoding algorithms.
文摘A household survey was carried out in Central Malawi to evaluate the goat marketing structure and systems in the rural areas using Nsundwe and Nkhoma areas in Lilongwe District as a case study. The analysis focused on identifying marketing systems of goats in Malawi by investigating the role of goats in an average Malawian rural household and how the current goat marketing systems affects that role. Goats play important role in Malawian rural households by way of providing food, income and as a capital reserve to be used in times critical times of food scarcity. The findings indicate that there is potential for goats to generate more income for the rural farmers, which can in turn help to improve household food security. The marketing system however apparently does not favour the farmers. The farmers seem not to know goat prices beyond the rural markets and hence have inadequate negotiating power to sell at optimum prices. Middlemen bought from farmers and finally sold the goats to urban consumers and retail shops. From the analysis, middlemen seemed to control the goat marketing system. Urban butchers sold the goats at 58% more than the value of farmers while retail shops sold at 137% more than the value of farmers. The differences reflect value-adding activities done at butchers and retail shops levels as well as transportation costs and profit margins. Though farmers may not engage in value adding, the finding implies that they would fetch more money if they supplied directly to the retail shops than to the middlemen. With access to more market information, they could also increase their bargaining power information with middlemen and sell the goats at relatively higher prices than the current. This paper details the results of the study.
基金partially supported by the National Science Foundation of China under Grant No.71090401/71090400
文摘Manufacturers’channel competition with service is examined in this paper.Specifically,the authors consider channel competition within a supply chain comprising two manufacturers and one single retailer where each manufacturer can choose to sell its products either directly to the end market(online channel,say)or through the potential retail channel,based on the profit maximization criterion,which is influenced by exogenous market conditions,such as the degree of competition,etc.Furthermore,the retailer provides additional demand-enhancing service to promote the manufacturer’s products distributed via it.If only one of the manufacturers sells products through the retailer,its products will be promoted by the additional retail service,which poaches demand of products of the manufacturer who adopts direct online channel.Products of both manufacturers are supported by the retailer’s promotional service when both distribute their product through the common retailer.Finally,some managerial implications are derived from numerical analyses of our model,which explain the phenomena in practice and conclude the paper.
基金supported by the Fundamental Research Funds for the Central Universities(No.JB160105)the“111 Project”of China(No.B08038)
文摘The outage performance of the multihop free-space optical(FSO) communication system with decode-and-forward(DF) protocol is studied by considering the joint effects of nonzero boresight pointing errors and atmospheric turbulence modeled by exponentiated Weibull(EW) distribution. The closed-form analytical expression of outage probability is derived, and the results are validated through Monte Carlo simulation. Furthermore, the detailed analysis is provided to evaluate the impacts of turbulence strength, receiver aperture size, boresight displacement, beamwidth and number of relays on the outage performance for the studied system.
