Energy Theft Detection in Smart Grids:Taxonomy,Comparative Analysis,Challenges,and Future Research Directions

Electricity theft is one of the major issues in developing countries which is affecting their economy badly.Especially with the introduction of emerging technologies,this issue became more complicated.Though many new energy theft detection(ETD)techniques have been proposed by utilising different data mining(DM)techniques,state&network(S&N)based techniques,and game theory(GT)techniques.Here,a detailed survey is presented where many state-of-the-art ETD techniques are studied and analysed for their strengths and limitations.Three levels of taxonomy are presented to classify state-of-the-art ETD techniques.Different types and ways of energy theft and their consequences are studied and summarised and different parameters to benchmark the performance of proposed techniques are extracted from literature.The challenges of different ETD techniques and their mitigation are suggested for future work.It is observed that the literature on ETD lacks knowledge management techniques that can be more effective,not only for ETD but also for theft tracking.This can help in the prevention of energy theft,in the future,as well as for ETD.

A Review of Research Directions and Research Methods of Farmland Weeds

Farmland weeds are an important part of farmland ecosystems.Research on farmland weeds is one of the major research fields in agricultural ecology.It is of great significance for achieving high yield,high quality and high efficiency in agriculture.In recent years,research on farmland weeds has focused on investigation of weed communities,research on weed seed banks,and research on weed control.These three research directions complement each other.Among them,the investigation work of weed communities and the research of weed seed banks are helpful for us to grasp the occurrence of farmland weeds more accurately and provide references for the control of farmland weeds.This article summarizes the research directions of farmland weeds in recent years(weed community investigation,weed seed bank,weed control)and the research methods used,provide reference value for the follow-up research work of farmland weeds,and provide theoretical support for promoting the development of rural ecological industry and building beautiful villages.

An analysis of major scientific problems and research paths of Gulong shale oil in Daqing Oilfield, NE China

After the preliminary basic research on the problems encountered during the production period of Gulong shale oil in the Songliao Basin, NE China, and the scientific exploration, the special characteristics of Gulong shale oil in terms of reservoir space, phase distribution, flow pattern, and mineral evolution are proposed. The main results are as follows :(1) The source of organic matter, mechanism of hydrocarbon generation and expulsion, and key factors affecting shale oil abundance;(2) The types and structural characteristics of the reservoir and their contribution to porosity and permeability;(3) The mineral origin and evolution of minerals and their influence on reservoir availability, sensitivity, and compressibility;(4) The rock mechanical characteristics and fracture propagation law of Gulong shale;(5) The shale oil products, phase change law and main control factors of adsorption and desorption conversion of Gulong shale oil;(6) The mechanism of shale oil-liquid, solid-liquid gas interaction and enhanced oil recovery. Three key research suggestions are proposed to realize the large-scale economic utilization of the Gulong shale oil as follows:(1) Deepen research on the mechanism of oil and gas generation and discharge, storage and transportation, to guide the selection of geological sweet spots of shale oil;(2) Deepen research on the compressibility and fracture initiation mechanism to support the selection of engineering sweet spots and optimization of engineering design;(3) Deepen research on the fluid interaction mechanism under reservoir conditions, os us to guide the optimization of development schemes and the selection of EOR technologies. A successful development of Gulong shale oil requires global experts and scholars to contribute multidisciplinary innovative ideas and technical ideas to solve production problems.

System dynamics analytical modeling approach for construction project management research: A critical review and future directions

Building and infrastructure construction projects can be viewed as a complex system consisting of many subsystems.Over the last two decades,considerable researches that use system dynamics(SD)as an analytical and modeling approach exist to address construction project management issues.However,only few critical reviews have been conducted to provide an in-depth understanding of SD application in construction project management.Moreover,many studies have failed to apply SD accurately.Therefore,the present study aims to gain an understanding of the current state of play and future directions in applying SD method in construction project management research,by undertaking a comprehensive review of 105 relevant articles published from 1994 to 2018.These articles are analyzed in terms of annual publication rate,key papers and their contribution,critical issues in SD application,and research topics.A significant increase in the number of publications in the last five years has been observed.When applying SD method to model construction system,the following aspects must be carefully considered:Model boundary,model development,model test,and model simulation.In addition,SD has been applied in a wide range of research topics,including(1)sustainable construction;(2)design error,rework,and change management;(3)risk management;(4)resource management;(5)decision making;(6)hybrid modeling;(7)safety management;(8)PPP project;and(9)organization performance.Based on the review findings,this study discusses three future research directions,namely,integration of SD with other methods,uncertainty analysis,and human factor analysis.This study can help researchers gain an in-depth understanding of the critical issues in the application of SD in construction management and the state-of-the-art of SD research.

Investigations and prospects of Fabry-Perot antennas:a review

Fabry-Perot(FP)antennas have characteristics of planar structures combined with high gain,and they have been widely used in wireless communications.With the progress of ongoing research,FP antennas have achieved various capabilities,but many of them are still under development,such as lowprofile,wideband,circular polarization,multi-band,low-radar cross section(RCS)and reconfigurable features.This paper discusses the theoretical analysis methods and research progress of FP antennas,and explains the realization methods of different features of FP antennas.In order to indicate different technologies for realizing various capabilities,the key technologies and features of some of the latest designs are described.Finally,the research situation and prospects of FP antennas are summarized to guide their research directions in the future.

Visualizing the emerging trends of biochar research and applications in 2019:a scientometric analysis and review

Biochar,derived from thermal pyrolysis of biomass,has been regarded as a low-cost,sustainable and beneficial material and widely applied in agriculture,environment and energy during the last two decades.To elucidate the research status timely and future trends in biochar field,CiteSpace is used to systematically analyze the related literature retrieved from the Web of Science core collection in 2019.Based on the keywords clustering analysis,it was found that“biochar production”,“organic pollutants removal”,“heavy metals immobilization”,“bioremediation”were the main hotspots in research covering biochar.“Bioremediation”is an emerging topic and deserves extensive attention due to its highly effective and environmentally friendly treatment of pollutants.Improving the phytoremediation effect,immobilizing functional microorganisms on biochar,and using microorganisms as raw materials to produce biochar were the common methods of biochar-assisted bioremediation.While studies focused on“soil quality and plant growth”and“biochar and global climate change”decreased,investigations concentrated in the toxicity of biochar to soil biota and ruminants are sustainably growing.Research on direct and catalytic thermal pyrolysis of green waste(mainly microalgae)for biofuels(bio-oil,biodiesel,syngas,etc.)and biochar production is increasing.Converting municipal wastes(e.g.,sewage sludge,fallen leaves)into biochar through pyrolysis was a suitable treatment for municipal waste and became a popular topic in recent time.Moreover,the biochar produced from these municipal wastes exhibited excellent performance in the removal of pollutants from wastewater and soil.This review may help to identify future directions in biochar research and applications.

Experimental researches on underwater target scattering properties in non-incident direction

In the bistatic case, theoretical analysis and experimental researches on underwater acoustic scattering properties of some submarine model are made in this paper. When sourcet target and receiver have complicated triangular configuration, the relationships among target strength, incidence angle and bistatic angle are obtained. The validity of this theory is verified by theoretical calculations and tank experiments. The research results can be directly used in bistatic or multistatic underwater acoustic detection systems.

Progress in the study of Yang-deficiency constitution in terms of Traditional Chinese Medicine:a narrative review

The Yang-deficiency constitution has been a hot topic of interest in recent years.Important research progress has been made in quantitative diagnostic criteria and auxiliary identification technologies,modern biological interpretations of the constitution characteristics,the association between the Yang-deficiency constitution and diseases,as well as the mechanisms of regulating the constitution.Yet,there are still some deficiencies and limitations.Herein,we systematically reviewed the research progress on the Yang-deficiency constitution by searching articles published in China National Knowledge Infrastructure Database,China Science and Technology Journal Database,Wanfang Database,PubMed,and Embase.The future development direction of the Yangdeficiency constitution should focus on developing objective constitution identification techniques,establishing animal models of Yang-deficiency constitution,conducting constitutional and diseaserelated research with a high level of evidence,combined with research on the full chain of the nine constitutions so as to obtain more scientific and objective conclusions.

Warfare, Imperialism, and the Making of Modern Chinese History： A Review Essay

This historiographic essay contends that warfare made and unmade the Qing dynasty between 1644 and 1911, and its study has helped to create the field of modem Chinese history during the past seventy years. It advances three principal claims. First, the literature on war, especially interstate conflict, can serve as a synecdoche for the development of the modem China field as a whole since the 1950s. The research interests of late Qing specialists have oscillated along an ＂external-internal-external＂ axis that corresponds with three distinct periods of intellectual inquiry, scholarly production, and generational dominance. Second, historians have reached inaccurate conclusions about the state capacity of the Qing Empire after 1840 through a crude analysis of the First Sino-Japanese War, a mistake they can rectify by adopting a longer-term perspective on the state-making process. Third, scholars have deftly traced the changing role of military power in modem Chinese politics but have also adopted the interpretive categories of wen and wu from literati discourse without sufficient critical reflection. In the future, researchers may seek to explore the intersection of warfare and the environment, technology, and ethnic identity, approaches that will continue to move the field in comparative, global, and Inner Asian directions.

Development on test equipment of coal slurry mixing tank

A coal slurry mixing tank is a key piece of equipment in the preparation of coal slurry for direct coal liquefaction.It is a gas-liquid-solid three-phase mixing device.Based on the performance of the existing coal slurry mixing equipment,a type of test equipment for horizontal continuous coal slurry preparation was developed,but to this point has limited research results.The test equipment consists of a mixing cylinder,mixer,stirring impeller and other components.Slurry mixing experiments were undertaken using the prototype,testing the performance of the device.A mathematical model was proposed specifically for the operation of a coal slurry mixing tank that is horizontally operated with high slurry concentration and rotary flow.The flow field in the horizontal coal mixing tank was simulated with the computational fluid dynamic (CFD) method.The experimental results match well with the CFD simulation results.Results show that the test device of a coal slurry mixing tank can be used to model the mixing of pulverized coal and the solvent oil.A strong correlation was obtained.