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Journal of Modern Power Systems and Clean Energy 2023年第6期11卷 1971-1981页

作者： tong cheng Zhenfei Tan Haiwang Zhong IEEE State Key Laboratory of Power Systems the Department of Electrical EngineeringTsinghua UniversityBeijingChina

Multi-energy integrations provide great opportunities for economic and efficient resource utilization. In the meantime, power system operation requires enough flexible resources to deal with contingencies such as transmission line tripping. Besides economic benefits, this paper focuses on the security benefits that can be provided by multi-energy integrations. This paper first proposes an operation scheme to coordinate multiple energy production and local system consumption considering transmission networks. The integrated flexibility model, constructed by the feasible region of integrated demand response(IDR), is then formulated to aggregate and describe local flexibility. Combined with system security constraints, a multi-energy system operation model is formulated to schedule multiple energy production, transmission, and consumption. The effects of local system flexibility on alleviating power flow violations during N-1 line tripping contingencies are then analyzed through a multi-energy system case. The results show that local system flexibility can not only reduce the system operation costs, but also reduce the probability of power flow congestion or violations by approximately 68.8% during N-1 line tripping contingencies.

关键词： Multi-energy system integrated flexibility feasible region integrated demand response N-1 security

Market Equilibrium Based on Cloud-edge Collaboration

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 96-104页

作者： tong cheng Haiwang Zhong Qing Xia the State Key Laboratory of Power Systems the Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

Market participants can only bid with lagged information disclosure under the existing market mechanism,which can lead to information asymmetry and irrational market behavior,thus influencing market *** promote rational bidding behavior of market participants and improve market efficiency,a novel electricity market mechanism based on cloudedge collaboration is proposed in this *** market information,called residual demand curve,is published to market participants in real-time on the cloud side,while participants on the edge side are allowed to adjust their bids according to the information disclosure prior to closure *** proposed mechanism can encourage rational bids in an incentive-compatible way through the process of dynamic equilibrium while protecting participants’*** paper further formulates the mathematical model of market equilibrium to simulate the process of each market participant’s strategic bidding behavior towards equilibrium.A case study based on the IEEE 30-bus system shows the proposed market mechanism can effectively guide bidding behavior of market participants,while condensing exchanged information and protecting privacy of participants.

关键词： Cloud-edge collaboration market mechanism residual demand curve strategic bidding

Model of Forming-Accretion on Blast Furnace Copper Stave and Industrial Application

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Journal of Iron and Steel Research International 2012年第7期19卷 1-5页

作者： WU tong cheng Su-sen School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

Copper staves have been equipped on nearly all of BF （blast furnaces） with volume over than 1000 m3 in China since their introduction from abroad about more than 10 years ago. Because of short application and lack of experience, phenomena of thickened or naked of copper stave happen occasionally which influence production severely. So it is important to study the model of forming-accretion on BF copper stave and realize real-time monitoring of forming-accretion on different copper staves. Therefore, mathematic model of calculating accretion thickness by heat flow of BF is proposed, and the calculated results indicate that accretion thickness could be kept at a reasonable range of around 50 mm by controlling heat flux around 22.0 kW/mz. The monitoring program based on the model was applied to a certain BF in China successfully, and it is found that slip of BF near the inner wall is one of most important reasons that cause fluctuation of accretion thickness. During the period of scheduled maintenance of the certain BF, the thickness of accretion measured through the static pressure holes is in good accordance with the value calculated by the monitoring program, so the results calculated by the monitoring program can be used to guide industrial production

关键词： blast furnace copper stave forming-accretion monitor industrial application

Risk factors of recurrent choledocholithiasis following therapeutic endoscopic retrograde cholangiopancreatography

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Hepatobiliary & Pancreatic Diseases International 2023年第3期22卷 282-287页

作者： Lin Li Jing Wang cheng-cheng tong Chi-Yi He Department of Gastroenterology The First Affiliated Hospital of Wannan Medical CollegeWuhu 241001China

Background:The risk factors for the recurrent choledocholithiasis after endoscopic retrograde cholangiopancreatography(ERCP)have not been well *** aim of this study was to explore the risk factors of recurrent ***:We carried out a retrospective analysis of data collected between January 1,2010 and January 1,*** analysis and multivariate analysis were used to explore the independent risk factors of recurrent choledocholithiasis following therapeutic ***:In total,598 patients were eventually selected for analysis,299 patients in the recurrent choledocholithiasis group and 299 patients in the control *** overall rate of recurrent choledocholithiasis was 6.91%.Multivariate analysis showed that diabetes[odds ratio(OR)=3.677,95%confidence interval(CI):1.875-7.209;P<0.001],fatty liver(OR=4.741,95%CI:1.205-18.653;P=0.026),liver cirrhosis(OR=3.900,95%CI:1.358-11.201;P=0.011),history of smoking(OR=3.773,95%CI:2.060-6.908;P<0.001),intrahepatic bile duct stone(OR=4.208,95%CI:2.220-7.976;P<0.001),biliary stent(OR=2.996,95%CI:1.870-4.800;P<0.001),and endoscopic papillary balloon dilation(EPBD)(OR=3.009,95%CI:1.921-4.715;P<0.001)were independent risk factors of recurrent ***,history of drinking(OR=0.183,95%CI:0.099-0.337;P<0.001),eating light food frequently(OR=0.511,95%CI:0.343-0.760;P=0.001),and antibiotic use before ERCP(OR=0.315,95%CI:0.200-0.497;P<0.001)were independent protective factors of recurrent ***:Patients with the abovementioned risk factors are more likely to have recurrent CBD *** who eat light food frequently and have a history of drinking are less likely to present with recurrent CBD calculi.

关键词： Recurrence Choledocholithiasis Endoscopic retrograde cholangiopancreatography

Adaptive Fuzzy Observer Backstepping Control for a Class of Uncertain Nonlinear Systems with Unknown Time-delay

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International Journal of Automation and computing 2010年第2期7卷 236-246页

作者： Shao-cheng tong Ning Sheng Department of Mathematics Liaoning University of Technology Jinzhou 121000 PRC

In this paper, a new adaptive fuzzy backstepping control approach is developed for a class of nonlinear systems with unknown time-delay and unmeasured states. Using fuzzy logic systems to approximate the unknown nonlinear functions, a fuzzy state observer is designed for estimating the unmeasured states. On the basis of the state observer and applying the backstepping technique, an adaptive fuzzy observer control approach is developed. The main features of the proposed adaptive fuzzy control approach not only guarantees that all the signals of the closed-loop system are semiglobally uniformly ultimately bounded, but also contain less adaptation parameters to be updated on-line. Finally, simulation results are provided to show the effectiveness of the proposed approach.

关键词： Fuzzy logic systems nonlinear time-delay systems adaptive backstepping control state observer stability analysis.

Reconstruction of convection coefficients of an elliptic equation in the plane by Dirichlet to Neumann map

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Science China Mathematics 2005年第1期48卷 40-56页

作者： tong Chongliang cheng Jin Yamamoto M. Institute of Mathematics Fudan UniversityShanghai 200433China Institute of MathematicsFudan UniversityShanghai 200433China Division of Computational Science E-Institute of Shanghai UniversitiesShanghai 200433China Department of Mathematical SciencesUniversity of TokyoTokyo 153-8914Japan

The inverse problem of determining two convection coefficients of an elliptic partial differential equation by Dirichlet to Neumann map is *** is well known that this is a severely ill-posed problem with high *** the inverse scattering technique for first order elliptic system in the plane and the theory of generalized analytic functions,we give a constructive method for this inverse problem.

关键词： inverse problems,Dirichlet to Neumann map,reconstruction,inverse scattering,elliptic system.

Laboratory insights into the effects of methane hydrate on the anisotropic joint elastic-electrical properties in fractured sandstones

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Petroleum Science 2023年第2期20卷 803-814页

作者： Sheng-Biao Liu tong-cheng Han Li-Yun Fu Shandong Provincial Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)QingdaoShandong266580China Laboratory for Marine Mineral Resources Pilot National Laboratory for Marine Science and TechnologyQingdaoShandong266071China

Fractured hydrate-bearing reservoirs show significantly anisotropic geophysical properties. The joint application of seismic and electromagnetic explorations is expected to accurately assess hydrate resources in the fractured reservoirs. However, the anisotropic joint elastic-electrical properties in such reservoirs that are the key to the successful application of the joint explorations, remain poorly understood. To obtain such knowledge, we designed and implemented dedicated laboratory experiments to study the anisotropic joint elastic-electrical properties in fractured artificial silica sandstones (with fracture density of about 6.2%, porosity of approximately 25.7%, and mean grainsize of 0.089 mm) with evolving methane hydrate. The experimental results showed that the anisotropic compressional wave velocities respectively increased and decreased with the forming and dissociating hydrate, and the variation in the increasing trend and the decreasing extent of the velocity perpendicular to the fractures were more significant than that parallel to the fractures, respectively. The experimental results also showed that the overall decreasing trend of the electrical conductivity parallel to the fractures was steeper than that perpendicular to the fractures during hydrate formation, and the general variations of the two conductivities with complex trend were similar during hydrate dissociation. The variations in the elastic and electrical anisotropic parameters with forming and dissociating hydrate were also found to be distinct. Interpretation of the experimental results suggested that the hydrate binding to the grains evolved to bridge the surfaces of fractures when saturation exceeded 10% during hydrate formation, and the bridging hydrate gradually evolved to floating in fractures during dissociation. The experimental results further showed that the anisotropic velocities and electrical conductivities were correlated with approximately consistent trends of different

关键词： Fractured hydrate reservoirs Elastic anisotropy Electrical anisotropy Joint elastic-electrical properties Hydrate distribution

Short-term load forecasting model based on gated recurrent unit and multi-head attention

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The Journal of China Universities of Posts and Telecommunications 2023年第3期30卷 25-31页

作者： Li Hao Zhang Linghua tong cheng Zhou Chenyang School of Communications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China School of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing 210003China

Short-term load forecasting(STLF)plays a crucial role in the smart ***,it is challenging to capture the long-time dependence and the nonlinear relationship due to the comprehensive fluctuations of the electrical *** this paper,an STLF model based on gated recurrent unit and multi-head attention(GRU-MA)is proposed to address the aforementioned *** proposed model accommodates the time series and nonlinear relationship of load data through gated recurrent unit(GRU)and exploits multi-head attention(MA)to learn the decisive features and long-term ***,the proposed model is compared with the support vector regression(SVR)model,the recurrent neural network and multi-head attention(RNN-MA)model,the long short-term memory and multi-head attention(LSTM-MA)model,the GRU model,and the temporal convolutional network(TCN)model using the public dataset of the Global Energy Forecasting Competition 2014(GEFCOM2014).The results demonstrate that the GRU-MA model has the best prediction accuracy.

关键词： deep learning short-term load forecasting(STLF) gated recurrent unit(GRU) multi-head attention(MA)

A quantitative interpretation of the saturation exponent in Archie’s equations

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Petroleum Science 2021年第2期18卷 444-449页

作者： tong-cheng Han Han Yan Li-Yun Fu School of Geosciences China University of Petroleum(East China)Qingdao 266580China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China

Saturation exponent is an important parameter in Archie’s equations;however,there has been no well-accepted physical interpretation for the saturation *** have theoretically derived Archie’s equations from the Maxwell–Wagner theory on the assumption of homogeneous fluid distribution in the pore space of clay-free porous *** theoretical derivations showed that the saturation exponent is in essence the cementation exponent for the water–air mixture and is quantitatively and explicitly related to the aspect ratio of the air bubbles in the *** results have provided a theoretical backup for the empirically obtained Archie’s equations and have offered a more physical and quantitative understanding of the saturation exponent.

关键词： Electrical properties Saturation exponent Archie equation Maxwell-Wagner theory

Adaptive Backstepping Output Feedback Control for SISO Nonlinear System Using Fuzzy Neural Networks

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International Journal of Automation and computing 2009年第2期6卷 145-153页

作者： Shao-cheng tong Yong-Ming Li Department of Basic Mathematics Liaoning University of Technology Jinzhou 121001 PRC

In this paper, a new fuzzy-neural adaptive control approach is developed for a class of single-input and single-output （SISO） nonlinear systems with unmeasured states. Using fuzzy neural networks to approximate the unknown nonlinear functions, a fuzzy- neural adaptive observer is introduced for state estimation as well as system identification. Under the framework of the backstepping design, fuzzy-neural adaptive output feedback control is constructed recursively. It is proven that the proposed fuzzy adaptive control approach guarantees the global boundedness property for all the signals, driving the tracking error to a small neighbordhood of the origin. Simulation example is included to illustrate the effectiveness of the proposed approach.

关键词： Nonlinear systems backstepping control adaptive fuzzy neural networks control state observer output feedback control.