Robust Nash Dynamic Game Strategy for User Cooperation Energy Efficiency in Wireless Cellular Networks

Recently, there is an emerging trend of addressing “energy efficiency” aspect of wireless communications. It has been shown that cooperating users relay each other\u27s information to improve data rates. The energy is limited in the wireless cellular network, but the mobile users refuse to relay. This paper presents an approach that encourages user cooperation in order to improve the energy efficiency. The game theory is an efficient method to solve such conflicts. We present a cellular framework in which two mobile users, who desire to communicate with a common base station, may cooperate via decode-and-forward relaying. In the case of imperfect information assumption, cooperative Nash dynamic game is used between the two users\u27 cooperation to tackle the decision making problems: whether to cooperate and how to cooperate in wireless networks. The scheme based on “cooperative game theory” can achieve general pareto-optimal performance for cooperative games, and thus, maximize the entire system payoff while maintaining fairness

Salinity significantly affects methane oxidation and methanotrophic community in Inner Mongolia lake sediments

Methanotrophs oxidize methane (CH4) and greatly help in mitigating greenhouse effect. Increased temperatures due to global climate change can facilitate lake salinization, particularly in the regions with cold semiarid climate. However, the effects of salinity on the CH4 oxidation activity and diversity and composition of methanotrophic community in the sediment of natural lakes at a regional scale are still unclear. Therefore, we collected lake sediment samples from 13 sites in Mongolian Plateau; CH4 oxidation activities of methanotrophs were investigated, and the diversity and abundance of methanotrophs were analyzed using real-time quantitative polymerase chain reaction and high throughput sequencing approach. The results revealed that the diversity of methanotrophic community decreased with increasing salinity, and community structure of methanotrophs was clearly different between the hypersaline sediment samples (HRS; salinity > 0.69%) and hyposaline sediment samples (HOS; salinity < 0.69%). Types II and I methanotrophs were predominant in HRS and HOS, respectively. Salinity was significantly positively correlated with the relative abundance of Methylosinus and negatively correlated with that of Methylococcus. In addition, CH4 oxidation rate and pmoA gene abundance decreased with increasing salinity, and salinity directly and indirectly affected CH4 oxidation rate via regulating the community diversity. Moreover, high salinity decreased cooperative association among methanotrophs and number of key methanotrophic species (Methylosinus and Methylococcus, e.g). These results suggested that salinity is a major driver of CH4 oxidation in lake sediments and acts by regulating the diversity of methanotrophic community and accociation among the methanotrophic species

Introduction to Special Issue - In-depth study of air pollution sources and processes within Beijing and its surrounding region (APHH-2 Beijing)

Abstract. The Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-Beijing) programme is an international collaborative project focusing on understanding the sources, processes and health effects of air pollution in the Beijing megacity. APHH-Beijing brings together leading China and UK research groups, state-of-the-art infrastructure and air quality models to work on four research themes: (1) sources and emissions of air pollutants; (2) atmospheric processes affecting urban air pollution; (3) air pollution exposure and health impacts; and (4) interventions and solutions. Themes 1 and 2 are closely integrated and support Theme 3, while Themes 1-3 provide scientific data for Theme 4 to develop cost-effective air pollution mitigation solutions. This paper provides an introduction to (i) the rationale of the APHH-Beijing programme, and (ii) the measurement and modelling activities performed as part of it. In addition, this paper introduces the meteorology and air quality conditions during two joint intensive field campaigns - a core integration activity in APHH-Beijing. The coordinated campaigns provided observations of the atmospheric chemistry and physics at two sites: (i) the Institute of Atmospheric Physics in central Beijing, and (ii) Pinggu in rural Beijing during 10 November – 10 December 2016 (winter) and 21 May- 22 June 2017 (summer). The campaigns were complemented by numerical modelling and automatic air quality and low-cost sensor observations in the Beijing megacity. In summary, the paper provides background information on the APHH-Beijing programme, and sets the scene for more focussed papers addressing specific aspects, processes and effects of air pollution in Beijing

Reinforcement Learning Optimization for Energy-Efficient Cellular Networks with Coordinated Multipoint Communications

Recently, there is an emerging trend of addressing “energy efficiency” aspect of wireless communications. And coordinated multipoint (CoMP) communication is a promising method to improve energy efficiency. However, since the downlink performance is also important for users, we should improve the energy efficiency as well as keeping a perfect downlink performance. This paper presents a control theoretical approach to study the energy efficiency and downlink performance issues in cooperative wireless cellular networks with CoMP communications. Specifically, to make the decisions for optimal base station grouping in energy-efficient transmissions in CoMP, we develop a Reinforcement Learning (RL) Algorithm. We apply the Q-learning of the RL Algorithm to get the optimal policy for base station grouping with introduction of variations at the beginning of the Q-learning to prevent Q from falling into local maximum points. Simulation results are provided to show the process and effectiveness of the proposed scheme

Advances in Electrochemical Detection Electrodes for As(III)

Arsenic is extremely abundant in the Earth’s crust and is one of the most common environmental pollutants in nature. In the natural water environment and surface soil, arsenic exists mainly in the form of trivalent arsenite (As(III)) and pentavalent arsenate (As(V)) ions, and its toxicity can be a serious threat to human health. In order to manage the increasingly serious arsenic pollution in the living environment and maintain a healthy and beautiful ecosystem for human beings, it is urgent to conduct research on an efficient sensing method suitable for the detection of As(III) ions. Electrochemical sensing has the advantages of simple instrumentation, high sensitivity, good selectivity, portability, and the ability to be analyzed on site. This paper reviews various electrode systems developed in recent years based on nanomaterials such as noble metals, bimetals, other metals and their compounds, carbon nano, and biomolecules, with a focus on electrodes modified with noble metal and metal compound nanomaterials, and evaluates their performance for the detection of arsenic. They have great potential for achieving the rapid detection of arsenic due to their excellent sensitivity and strong interference immunity. In addition, this paper discusses the relatively rare application of silicon and its compounds as well as novel polymers in achieving arsenic detection, which provides new ideas for investigating novel nanomaterial sensing. We hope that this review will further advance the research progress of high-performance arsenic sensors based on novel nanomaterials

Influence of JFET Width on Short-Circuit Robustness of 1200 V SiC Power MOSFETs

This paper investigates and compares the static performance and short-circuit (SC) robustness of 1200 V SiC MOSFETs with varying JFET widths (WJFET = 2.0–5.0 μm). Short-circuit measurements as well as electrical-thermal simulations are used to identify thermal distribution and maximum electrical field, providing valuable insights into the design limits. The devices under test (DUTs) with narrow and wide WJFET exhibit different failure mechanisms under SC stress. After the short-circuit failure, interlayer dielectric (ILD) cracks are observed in DUTs with narrow JFET width (WJFET JFET exhibits varying trends under high temperature conditions (100 °C). These results can help verify the different failure mechanisms and determine an optimal JFET design to improve the trade-off between the static performance and SC ruggedness of the SiC MOSFETs

New methodology for aquifer influx status classification for single wells in a gas reservoir with aquifer support

AbstractFor gas reservoirs with strong bottom or edge aquifer support, the most important thing is avoiding aquifer breakthrough in a gas well. Water production in gas wells does not only result in processing problems in surface facilities, but it also explicitly reduces well productivity and reservoir recovery. There are a lot of studies on the prediction of water breakthrough time, but they are not completely practicable due to reservoir heterogeneity. This paper provides a new method together with three diagnostic curves to identify aquifer influx status for single gas wells; the aforementioned curves are based on well production and pressure data. The whole production period of a gas well can be classified into three periods based on the diagnostic curves: no aquifer influx period, early aquifer influx period, and middle-late aquifer influx period. This new method has been used for actual gas well analysis to accurately identify gas well aquifer influx status and the water breakthrough sequence of all wells in the same gas field. Additionally, the evaluation results are significantly beneficial for well production rate optimization and development of an effective gas field

Robust Nash Dynamic Game Strategy for User Cooperation Energy Efficiency in Wireless Cellular Networks

Recently, there is an emerging trend of addressing “energy efficiency” aspect of wireless communications. It has been shown that cooperating users relay each other's information to improve data rates. The energy is limited in the wireless cellular network, but the mobile users refuse to relay. This paper presents an approach that encourages user cooperation in order to improve the energy efficiency. The game theory is an efficient method to solve such conflicts. We present a cellular framework in which two mobile users, who desire to communicate with a common base station, may cooperate via decode-and-forward relaying. In the case of imperfect information assumption, cooperative Nash dynamic game is used between the two users' cooperation to tackle the decision making problems: whether to cooperate and how to cooperate in wireless networks. The scheme based on “cooperative game theory” can achieve general pareto-optimal performance for cooperative games, and thus, maximize the entire system payoff while maintaining fairness