To support the drastic growth of wireless multimedia services and the requirements of ubiquitous access, numerous wireless infrastructures which consume enormous energy, such as macrocell, small cell, distributed ante...To support the drastic growth of wireless multimedia services and the requirements of ubiquitous access, numerous wireless infrastructures which consume enormous energy, such as macrocell, small cell, distributed antenna systems and wireless sensor networks, have been deployed. Under the background of environmental protection, improving the energy efficiency（EE） in wireless networks is becoming more and more important. In this paper, an EE enhancement scheme in heterogeneous networks（Het Nets） by using a joint resource allocation approach is proposed. The Het Nets consists of a mix of macrocell and small cells. Firstly, we model this strategic coexistence as a multi-agent system in which decentralized resource management inspired from Reinforcement Learning are devised. Secondly, a Q-learning based joint resource allocation algorithm is designed. Meanwhile, with the consideration of the time-varying channel characteristics, we take the long-term learning reward into account. At last, simulation results show that the proposed decentralized algorithm can approximate to centralized algorithm with low-complexity and obtain high spectral efficiency（SE） in the meantime.展开更多
This paper analyzes the accuracy and appropriacy of the recorded data from a group of Chinese-speaking English learners who has finished three communicative tasks set in different contexts.It also tries to find out ho...This paper analyzes the accuracy and appropriacy of the recorded data from a group of Chinese-speaking English learners who has finished three communicative tasks set in different contexts.It also tries to find out how the participants' learning history and the present Chinese EFL context influence their performance.The results suggest that the participants rely on a limited set of request,apology,and refusal strategies.And it is evident that low-level learners often refer to their L1 for sentence constructions and lexical items.Although the evidence is still fragmentary,enough exists to indicate that transfer involving discourse can often occur in foreign language acquisition.展开更多
随着航空运输业的快速发展,传统的基于飞行程序的燃油预测无法再精确计算飞机携带的燃油量,因此如何精确地进行燃油预测成为各大航空公司稳健发展的重要目标。为了更科学地解决燃油决策量问题,首先对航迹数据进行处理,以便在计算燃油消...随着航空运输业的快速发展,传统的基于飞行程序的燃油预测无法再精确计算飞机携带的燃油量,因此如何精确地进行燃油预测成为各大航空公司稳健发展的重要目标。为了更科学地解决燃油决策量问题,首先对航迹数据进行处理,以便在计算燃油消耗(简称油耗)中使用,然后依据飞机数据基础用户手册(BADA,user manual for the based of aircraft data)数据库的油耗计算方法,在假定各航段燃油消耗率恒定的情况下建立了飞机下降进近阶段的油耗模型,并通过对所得油耗数据进行分析,提出某一飞行阶段航空公司的燃油携带建议值,最后依据中国民用航空西南地区空中交通管理局云南分局提供的雷达航迹数据进行仿真验证,验证了所设计的油耗模型较之前的传统方法更准确可行。展开更多
文摘To support the drastic growth of wireless multimedia services and the requirements of ubiquitous access, numerous wireless infrastructures which consume enormous energy, such as macrocell, small cell, distributed antenna systems and wireless sensor networks, have been deployed. Under the background of environmental protection, improving the energy efficiency（EE） in wireless networks is becoming more and more important. In this paper, an EE enhancement scheme in heterogeneous networks（Het Nets） by using a joint resource allocation approach is proposed. The Het Nets consists of a mix of macrocell and small cells. Firstly, we model this strategic coexistence as a multi-agent system in which decentralized resource management inspired from Reinforcement Learning are devised. Secondly, a Q-learning based joint resource allocation algorithm is designed. Meanwhile, with the consideration of the time-varying channel characteristics, we take the long-term learning reward into account. At last, simulation results show that the proposed decentralized algorithm can approximate to centralized algorithm with low-complexity and obtain high spectral efficiency（SE） in the meantime.
文摘This paper analyzes the accuracy and appropriacy of the recorded data from a group of Chinese-speaking English learners who has finished three communicative tasks set in different contexts.It also tries to find out how the participants' learning history and the present Chinese EFL context influence their performance.The results suggest that the participants rely on a limited set of request,apology,and refusal strategies.And it is evident that low-level learners often refer to their L1 for sentence constructions and lexical items.Although the evidence is still fragmentary,enough exists to indicate that transfer involving discourse can often occur in foreign language acquisition.
文摘随着航空运输业的快速发展,传统的基于飞行程序的燃油预测无法再精确计算飞机携带的燃油量,因此如何精确地进行燃油预测成为各大航空公司稳健发展的重要目标。为了更科学地解决燃油决策量问题,首先对航迹数据进行处理,以便在计算燃油消耗(简称油耗)中使用,然后依据飞机数据基础用户手册(BADA,user manual for the based of aircraft data)数据库的油耗计算方法,在假定各航段燃油消耗率恒定的情况下建立了飞机下降进近阶段的油耗模型,并通过对所得油耗数据进行分析,提出某一飞行阶段航空公司的燃油携带建议值,最后依据中国民用航空西南地区空中交通管理局云南分局提供的雷达航迹数据进行仿真验证,验证了所设计的油耗模型较之前的传统方法更准确可行。
