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Dy.amic control of district heating networks with integrated emission modelling:A dy.amic knowledge graph approach

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Energy and AI

Energy.and AI 2024年第3期17卷 29-47页

作者： Markus Hofmeister Kok Foong Lee y.-kai tsai Magnus Müller Karthik Nagarajan Sebastian Mosbach Jethro Akroy. Markus Kraft Department of Chemical Engineering and Biotechnology University of CambridgePhilippa Fawcett DriveCambridgeCB30ASUnited Kingdom Cambridge Centre for Advanced Research and Education in Singapore CARES Ltd.1 Create WayCREATE Tower#05-05138602Singapore CMCL Innovations Sheraton HouseCambridgeCB30AXUnited Kingdom The Alan Turing Institute 96 Euston RoadLondonNW12DBUnited Kingdom

This paper presents a knowledge graph-based approach for the dy.amic control of a district heating network with integrated emission dispersion modelling. We propose an interoperable and extensible implementation to forecast the anticipated heat demand of a municipal heating network, minimise associated total generation cost based on a previously.devised methodology. and couple it with dispersion simulations for induced airborne pollutants to provide automatic insights into air quality.implications of various heat sourcing strategies. We create cross-domain interoperability.in the nexus of energy.and air quality.via newly.developed ontologies and semantic software agents, which can be chained together via The World Avatar dy.amic knowledge graph to resemble the behaviour of complex sy.tems. Furthermore, we integrate the City.Energy.Analy.t into this ecosy.tem to provide building-level insights into energy.demand and renewable generation potential to foster strategic analy.es and scenario planning. Underly.ng calculations use building and weather data from the knowledge graph in place of inherent assumptions in the official software release, facilitating a more data-driven approach. All use cases are implemented for a mid-size town in Germany.as a proof-of-concept, and a unified visualisation interface is provided, allowing for the examination of 3D buildings alongside their corresponding energy.demand and supply.time series, as well as emission dispersion data. With this work, we outline the potential of Semantic Web technologies to connect digital twins for holistic energy.modelling in smart cities, thereby.addressing the increasing complexity.of interconnected energy.sy.tems.

关键词： Knowledge graph Digital twin Inter operability Energy.modelling Emi ssion dispersi on

Hy.rogen and nitrogen absorption properties of Ce-added Zr_(2)(Fe_(1-x)Ni_(x)) alloy.

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Journal of Rare Earths 2024年第6期42卷 1136-1141,I0005页

作者： kai y.n Xiaopeng Liu State Key.Laboratory.of Advanced Materials for Smart Sensing GRINM Group Co.Ltd.Beijing10088China GRIMAT Engineering Institute Co. Ltd.Beijing101407China General Research Institute of Nonferrous Metals Beijing100088China

To improve the nitriding resistance of Zr_(2)Fe alloy.the Ce-added Zr_(2)(Fe_(1-x)Ni_(x))(x=0,0.15,0.3,0.5)alloy. were prepared by.magnetic levitation melting *** effects of Ni substitution for Fe on the phase structure,hy.rogen and nitrogen absorption properties of the alloy. were investigated by.X-ray.diffraction,scanning electron microscopy.and p-c isotherm *** experimental results show that Ni substitution can effectively.inhibit the formation of both α-Zr and ZrFe_(2) phases and promote the formation of C16 structure Zr_(2)(Fe,Ni)phase,causing Ni-substituted alloy. to exhibit low nitrogen absorption rate and *** 623 K under 0.5 MPa nitrogen pressure,the nitrogen absorption capacity.of Ce-added Zr_(2)(Fe_(0.5)Ni_(0.5))alloy.reaches to 0.8 mL/g,much lower than that of Zr_(2)Fe alloy.1.5 mL/g).Ni substitution decreases the cry.tal cell volume of the C_(16)Zr_(2)(Fe,Ni)phase,resulting in an increase in the hy.rogen absorption equilibrium *** 623 K under 0.05 MPa hy.rogen pressure,the hy.rogen absorption capacity.decreases from 1.46 wt%of Zr_(2)Fe alloy.to 1.41 wt%of Ce-added Zr_(2)(Fe_(0.5)Ni_(0.5))alloy.

关键词： Zr_(2)Fe alloy Ce Pressure-composition isotherm Hy.rogen absorption Nitrogen absorption Rare earths

Adaptive state-constrained/model-free iterative sliding mode control for aerial robot trajectory.tracking

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 603-618页

作者： Chen AN Jiaxi ZHOU kai WANG College of Mechanical and Vehicle Engineering Hunan UniversityChangsha 410082China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHong KongChina

This paper develops a novel hierarchical control strategy.for improving the trajectory.tracking capability.of aerial robots under parameter *** hierarchical control strategy.is composed of an adaptive sliding mode controller and a model-free iterative sliding mode controller(MFISMC).A position controller is designed based on adaptive sliding mode control(SMC)to safely.drive the aerial robot and ensure fast state convergence under external ***,the MFISMC acts as an attitude controller to estimate the unmodeled dy.amics without detailed knowledge of aerial ***,the adaption laws are derived with the Ly.punov theory.to guarantee the asy.ptotic tracking of the sy.tem ***,to demonstrate the performance and robustness of the proposed control strategy.numerical simulations are carried out,which are also compared with other conventional strategies,such as proportional-integralderivative(PID),backstepping(BS),and *** simulation results indicate that the proposed hierarchical control strategy.can fulfill zero steady.state error and achieve faster convergence compared with conventional strategies.

关键词： aerial robot hierarchical control strategy model-free iterative sliding mode controller(MFISMC) trajectory.tracking reinforcement learning

Adaptive learning-based optimal tracking control sy.tem design and analy.is of a disturbed nonlinear hy.ersonic vehicle model

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Science China(Technological Sciences) 2024年第6期67卷 1893-1906页

作者： AN kai WANG ZhenGuo HUANG Wei Hy.ersonic Technology.Laboratory National University of Defense TechnologyChangsha410073China

We propose an adaptive learning-based optimal control scheme for height-velocity.control models considering model uncertainties and external disturbances of hy.ersonic winged-cone *** longitudinal nonlinear model is first established and transformed into the control-oriented error equations,and the control scheme is organized by.a steady.compensation *** overcome and eliminate the impact of model uncertainties and external disturbances,an adaptive radial basis function neural network(RBFNN)is designed by.a q-gradient *** the height-velocity.error sy.tem with estimated uncertainties into account,the adaptive learning-based optimal tracking control(ALOTC)scheme is proposed by.combining the critic-only.adaptive dy.amic programming(ADP)framework and parameter optimization of sy.tem settling ***,a novel weight update law is proposed to satisfy.the online iteration requirements,and the algorithm convergence and closedloop stability.are discussed by.the Ly.punov ***,four simulation cases are provided to prove the effectiveness,accuracy.and robustness of the proposed scheme for the hy.ersonic longitudinal control sy.tem.

关键词： optimal tracking control adaptive dy.amic programming RBFNN hy.ersonic vehicle

Sequential Propagation of Chaos for Mean-Field BSDE Sy.tems

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Chinese Annals of Mathematics,Series B 2024年第1期45卷 11-40页

作者： Xiaochen LI kai DU Shanghai Center for Mathematical Sciences Fudan UniversityShanghai 200433China. Shanghai Artificial Intelligence Laboratory 701 Yunjin RoadShanghai 200433China

A new class of backward particle sy.tems with sequential interaction is proposed to approximate the mean-field backward stochastic differential *** is proven that the weighted empirical measure of this particle sy.tem converges to the law of the McKean-Vlasov sy.tem as the number of particles *** on the Wasserstein met-ric,quantitative propagation of chaos results are obtained for both linear and quadratic growth ***,numerical experiments are conducted to validate our theoretical results.

关键词： Backward propagation of chaos Particle sy.tem Sequential interaction McKean-Vlasov BSDE Convergence rate

Study.on macro and micro shear strength of continuously.graded and gap-graded sand

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Particuology 2024年第3期86卷 101-116页

作者： Peiran Zhao Songy. Liu kai Wu School of Transportation Southeast UniversityNanjing210096China

The particle gradation of sand has a significant influence on its shear strength,y.t the similarities and differences between the effects of continuous and gap grading have y.t to be fully.*** this study.the discrete element method(DEM)was used to simulate biaxial tests on granular samples that were both continuously.graded and *** macroscopic analy.is revealed that the shear strength of continuously.graded sands increases initially.and then decreases as the uniformity.of particle size distribution *** the other hand,the lack of medium particles in gap-graded sands amplifies the difference in particle size between coarse and fine particles,leading to a decrease in shear ***,both continuous and gap gradings affect the internal packing structure of the particle assembly.which consequently.affects particle stress distributions,contact forces,coordination numbers,stress-induced anisotropies,and contact force networks,thus having an impact on the macroscopic shear *** global uniformity.of particle size distribution was unidirectionally.affected by.continuous grading,while gap grading had a locally.bidirectional *** findings provide a better understanding of the effects of particle grading on the macroscopic shear strength of sands.

关键词： Biaxial test Shear strength Particle gradation Discrete element method Micromechanics

Robustness of the octupole collectivity.in 144Ba within the cranking covariant density.functional theory.in 3D lattice

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Nuclear Science and Techniques 2024年第8期35卷 124-131页

作者： Ze‑kai Li y.an‑y.an Wang Mathematics and Phy.ics Department North China Electric Power UniversityBeijing 102206China Hebei Key.Laboratory.of Phy.ics and Energy.Technology North China Electric Power UniversityBaoding 071000China

The octupole deformation and collectivity.in octupole double-magic nucleus 144Ba are investigated using the Cranking covariant density.functional theory.in a three-dimensional lattice *** reduced B(E3)transition probability.is implemented for the first time in semiclassical approximation based on the microscopically.calculated electric octupole *** available data,including the I-ωrelation and electric transitional probabilities B(E2)and B(E3)are well ***,it is shown that the ground state of 144Ba exhibits axial octupole and quadrupole deformations that persist up to high spins(I≈24h).

关键词： Octupole collectivity Cranking covariant density.functional theory Rotational spectrum Electric transitional probabilities

Autonomous navigation method of satellite constellation based on adaptive forgetting factors

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Chinese Journal of Aeronautics 2024年第7期37卷 317-332页

作者： Dong WANG Jing y.NG kai XIONG School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Science and Technology.on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100094China

To address the problem that model uncertainty.and unknown time-vary.ng sy.tem noise hinder the filtering accuracy.of the autonomous navigation sy.tem of satellite constellation,an autonomous navigation method of satellite constellation based on the Unscented Kalman Filter with Adaptive Forgetting Factors(UKF-AFF)is *** process noise covariance matrix is estimated online with the strategy.that combines covariance matching and adaptive adjustment of forgetting *** adaptive adjustment coefficient based on squared Mahalanobis distance of state residual is employ.d to achieve online regulation of forgetting factors,equipping this method with more *** intersatellite direction vector obtained from photographic observations is introduced to determine the constellation satellite orbit together with the distance measurement to avoid rank deficiency.*** that the number of available measurements varies online with intersatellite visibility.in practical applications such as time-vary.ng constellation configurations,the smooth covariance matrix of state correction determined by.innovation and gain is adopted and constructed *** analy.is of the proposed method is also *** effectiveness of the proposed method is verified by.the Monte Carlo simulation and comparison *** estimation accuracy.of constellation position and velocity.of UKF-AFF is improved by.30%and 44%respectively.compared to those of the extended Kalman filter,and the method proposed is also better than other several adaptive filtering methods in the presence of significant model uncertainty.

关键词： Constellation autonomous navigation Unscented Kalman filter Adaptive forgetting factor Model uncertainty Stability.analy.is

Impact of the Political Risk on Food Reserve Ratio:Evidence Across Countries

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Journal of Sy.tems Science & Complexity 2024年第5期37卷 2071-2103页

作者： XING kai LI Shang y.NG Xiaoguang School of Economics&Management Nanchang UniversityNanchang330031China Department of Statistics and Data Science National University of Singapore119077Singapore Academy.of Mathematics and Sy.tems Science Chinese Academy of SciencesBeijing100190China University.of Chinese Academy.of Sciences Beijing100190China

Using an unbalanced panel data covering 75 countries from 1991 to 2019,the authors explore how the political risk impacts on food reserve *** empirical findings show that an increasing political risk negatively.affects food reserve ratio,and the same effects hold for both internal risk and external ***,the authors find that the increasing external or internal risks both negatively.affect food production and food exports,but external risk does not significantly.impact food imports and it positively.impacts food consumption,while internal risk negatively.impacts food imports and food *** results suggest that most governments have difficulty.raising subsequent food reserve ratios in face of an increasing political risk,no matter if it is an internal risk or an external risk although the mechanisms behind the impacts are different.

关键词： External risk food reserve ratio internal risk political risk