In this paper we consider data transmission in a decode-and-forward(DF)relay-assisted network in which the relay is energy harvesting(EH) powered while the base station(BS) is power-grid powered.Our purpose is to maxi...In this paper we consider data transmission in a decode-and-forward(DF)relay-assisted network in which the relay is energy harvesting(EH) powered while the base station(BS) is power-grid powered.Our purpose is to maximize the BS's energy efficiency(EE) while making full use of the relay's renewable energy and satisfying the specific average throughput requirements.In contrast to existing literature on energy harvesting system which only considers the radio transmission power,we take the static circuit power into account as well.We formulate the EE optimization problem and prove that the EE of the BS and relay are both quasiconvex in the instantaneous transmission rate.Then we divide the complex optimization problem into two point-to-point link level optimization parts and propose an energyefficient resource allocation(EERA) scheme in which power control and sleep mode management are jointly used.The simulation results demonstrate that EERA may achieve good energy saving effects.We also compare the EE of an energy harvesting relay system with a power-grid powered one and provide more insight into the EE problem of energy harvesting relay system.展开更多
Sustainability on farms is a challenge to competitiveness in the globalized market. In this scenario, due to the strong environmental, economic and social appeal, crop-livestock-forest integration systems have been co...Sustainability on farms is a challenge to competitiveness in the globalized market. In this scenario, due to the strong environmental, economic and social appeal, crop-livestock-forest integration systems have been considered as the future of agriculture. Regarding the economic approach, this system is based on the diversification of income generating activities, with revenue entry at different times, rationalization of resource use and reduction of risk of financial losses. Thus, the purpose of this work was to carry out the economic analysis of a crop-livestock-forest integration system, located at Boa Vereda＇s farm, in the municipality of Cachoeira Dourada in the state of Goi^is in the central-west region of Brazil. The system was composed of the following traditional crops of the region： soybean, corn, pasture, beef cattle and eucalyptus. The technical coefficients and the prices used for economic evaluation were obtained from the experimental unit and from the local market when crops were harvested in 2016/2017. The economic indicators used to assess economic viability were the net present value （NPV） and the equivalent annual uniform value （EAUV）. The results showed a return greater than the opportunity cost of the land, showing the attractiveness of the crop-livestock-forest integration system. Thus, this system represents an economically viable alternative that, among other benefits, allows the diversification of its sources of income, with a reduction of risk.展开更多
基金supported by National programs for High Technology Research and Development(2012AA011402)National Basic Research Program of China(2012CB316002)National Nature Science Foundation of China(61172088)
文摘In this paper we consider data transmission in a decode-and-forward(DF)relay-assisted network in which the relay is energy harvesting(EH) powered while the base station(BS) is power-grid powered.Our purpose is to maximize the BS's energy efficiency(EE) while making full use of the relay's renewable energy and satisfying the specific average throughput requirements.In contrast to existing literature on energy harvesting system which only considers the radio transmission power,we take the static circuit power into account as well.We formulate the EE optimization problem and prove that the EE of the BS and relay are both quasiconvex in the instantaneous transmission rate.Then we divide the complex optimization problem into two point-to-point link level optimization parts and propose an energyefficient resource allocation(EERA) scheme in which power control and sleep mode management are jointly used.The simulation results demonstrate that EERA may achieve good energy saving effects.We also compare the EE of an energy harvesting relay system with a power-grid powered one and provide more insight into the EE problem of energy harvesting relay system.
文摘Sustainability on farms is a challenge to competitiveness in the globalized market. In this scenario, due to the strong environmental, economic and social appeal, crop-livestock-forest integration systems have been considered as the future of agriculture. Regarding the economic approach, this system is based on the diversification of income generating activities, with revenue entry at different times, rationalization of resource use and reduction of risk of financial losses. Thus, the purpose of this work was to carry out the economic analysis of a crop-livestock-forest integration system, located at Boa Vereda＇s farm, in the municipality of Cachoeira Dourada in the state of Goi^is in the central-west region of Brazil. The system was composed of the following traditional crops of the region： soybean, corn, pasture, beef cattle and eucalyptus. The technical coefficients and the prices used for economic evaluation were obtained from the experimental unit and from the local market when crops were harvested in 2016/2017. The economic indicators used to assess economic viability were the net present value （NPV） and the equivalent annual uniform value （EAUV）. The results showed a return greater than the opportunity cost of the land, showing the attractiveness of the crop-livestock-forest integration system. Thus, this system represents an economically viable alternative that, among other benefits, allows the diversification of its sources of income, with a reduction of risk.
