期刊文献+
共找到57,231篇文章
< 1 2 250 >
每页显示 20 50 100
The potential and challenges of large language model agent systems in chemical process simulation: from automated modeling to intelligent design
1
作者 Wenli Du Shaoyi Yang 《Frontiers of Chemical Science and Engineering》 2025年第10期137-143,共7页
Large language model-based agent systems are emerging as transformative technologies in chemical process simulation, enhancing efficiency, accuracy, and decision-making. By automating data analysis across structured a... Large language model-based agent systems are emerging as transformative technologies in chemical process simulation, enhancing efficiency, accuracy, and decision-making. By automating data analysis across structured and unstructured sources—including process parameters, experimental results, simulation data, and textual specifications—these systems address longstanding challenges such as manual parameter tuning, subjective expert reliance, and the gap between theoretical models and industrial application. This paper reviews the key barriers to broader adoption of large language model-based agent systems, including unstable software interfaces, limited dynamic modeling accuracy, and difficulties in multimodal data integration, which hinder scalable deployment. We then survey recent progress in domain-specific foundation models, model interpretability techniques, and industrial-grade validation platforms. Building on these insights, we propose a technical framework centered on three pillars: multimodal task perception, autonomous planning, and knowledge-driven iterative optimization. This framework supports adaptive reasoning and robust execution in complex simulation environments. Finally, we outline a next-generation intelligent paradigm where natural language-driven agent workflows unify high-level strategic intent with automated task execution. The paper concludes by identifying future research directions to enhance robustness, adaptability, and safety, paving the way for practical integration of large language model based agent systems into industrial-scale chemical process simulation. 展开更多
关键词 LLM agent systems chemical process simulation automated modeling
原文传递
Effect of terminal boundary protection on the spread of computer viruses:modeling and simulation
2
作者 Kai GAO Lixin ZHANG +2 位作者 Yabing YAO Yang YANG Fuzhong NIAN 《Frontiers of Information Technology & Electronic Engineering》 2025年第9期1637-1648,共12页
The diversity and complexity of the user population on the campus network increase the risk of computer virus infection during terminal information interactions.Therefore,it is crucial to explore how computer viruses ... The diversity and complexity of the user population on the campus network increase the risk of computer virus infection during terminal information interactions.Therefore,it is crucial to explore how computer viruses propagate between terminals in such a network.In this study,we establish a novel computer virus spreading model based on the characteristics of the basic network structure and a classical epidemic-spreading dynamics model,adapted to real-world university scenarios.The proposed model contains six groups:susceptible,unisolated latent,isolated latent,infection,recovery,and crash.We analyze the proposed model's basic reproduction number and disease-free equilibrium point.Using real-world university terminal computer virus propagation data,a basic computer virus infection rate,a basic computer virus removal rate,and a security protection strategy deployment rate are proposed to define the conversion probability of each group and perceive each group's variation tendency.Furthermore,we analyze the spreading trend of computer viruses in the campus network in terms of the proposed computer virus spreading model.We propose specific measures to suppress the spread of computer viruses in terminals,ensuring the safe and stable operation of the campus network terminals to the greatest extent. 展开更多
关键词 Campus network terminal security Spread of computer virus model Analogue simulation Terminal protection measures
原文传递
Multi-agent Based Hierarchy Simulation Models of Carrier-based Aircraft Catapult Launch 被引量:19
3
作者 王维军 屈香菊 郭林亮 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2008年第3期223-231,共9页
With the aid of multi-agent based modeling approach to complex systems, the hierarchy simulation models of carrier-based aircraft catapult launch are developed. Ocean, carrier, aircraft, and atmosphere are treated as ... With the aid of multi-agent based modeling approach to complex systems, the hierarchy simulation models of carrier-based aircraft catapult launch are developed. Ocean, carrier, aircraft, and atmosphere are treated as aggregation agents, the detailed components like catapult, landing gears, and disturbances are considered as meta-agents, which belong to their aggregation agent. Thus, the model with two layers is formed i.e. the aggregation agent layer and the meta-agent layer. The information communication among all agents is described. The meta-agents within one aggregation agent communicate with each other directly by information sharing, but the meta-agents, which belong to different aggregation agents exchange their information through the aggregation layer first, and then perceive it from the sharing environment, that is the aggregation agent. Thus, not only the hierarchy model is built, but also the environment perceived by each agent is specified. Meanwhile, the problem of balancing the independency of agent and the resource consumption brought by real-time communication within multi-agent system (MAS) is resolved. Each agent involved in carrier-based aircraft catapult launch is depicted, with considering the interaction within disturbed atmospheric environment and multiple motion bodies including carrier, aircraft, and landing gears. The models of reactive agents among them are derived based on tensors, and the perceived messages and inner frameworks of each agent are characterized. Finally, some results of a simulation instance are given. The simulation and modeling of dynamic system based on multi-agent system is of benefit to express physical concepts and logical hierarchy clearly and precisely. The system model can easily draw in kinds of other agents to achieve a precise simulation of more complex system. This modeling technique makes the complex integral dynamic equations of multibodies decompose into parallel operations of single agent, and it is convenient to expand, maintain, and reuse the program codes. 展开更多
关键词 multi-agent system (MAS) multi-agent based modeling (MABM) TENSOR carrier-based aircraft catapult launch hierarchy simulation model
在线阅读 下载PDF
Assessment of shear wave velocity models in the Southeast Qinghai-Xizang Plateau with full-wave simulation
4
作者 Wenpei Miao Guoliang Li +2 位作者 Fenglin Niu Kai Tao Yonghua Li 《Earthquake Science》 2025年第3期159-171,共13页
Various velocity models have been built for Southeast Qinghai-Xizang Plateau with the purpose of revealing the internal dynamics and estimating local seismic hazards.In this study,we use a 3-D full-waveform modeling p... Various velocity models have been built for Southeast Qinghai-Xizang Plateau with the purpose of revealing the internal dynamics and estimating local seismic hazards.In this study,we use a 3-D full-waveform modeling package to systematically validate three published continental-scale velocity models,that is,Shen2016,FWEA18,and USTClitho1.0,leveraging the ample datasets in Southeast Qinghai-Xizang Plateau region.Travel time residuals and waveform similarities are measured between observed empirical Green’s functions and synthetic waveforms.The results show that the Shen2016 model,derived from traditional surface wave tomography,performs best in fitting Rayleigh waves in the Southeast Qinghai-Xizang Plateau,followed by FWEA18,built from full-waveform inversion of long-period body and surface waves.The USTClitho1.0 model,although inverted from body wave datasets,is comparable with FWEA18 in fitting Rayleigh waves.The results also show that all the models are faster than the ground-truth model and show relatively large travel-time residuals and poor waveform similarities at shorter period bands,possibly caused by small-scale structural heterogeneities in the shallower crust.We further invert the time residuals for spatial velocity residuals and reveal that all three models underestimate the amplitudes of high-and low-velocity anomalies.The underestimated amplitude is up to 4%,which is non-negligible considering that the overall amplitude of anomalies is only 5%−10%in the crust.These results suggest that datasets and the inversion method are both essential to building accurate models and further refinements of these models are necessary. 展开更多
关键词 Qinghai-Xizang Plateau tomography models fullwave simulation model validation
在线阅读 下载PDF
Fine-tuning a large language model for automating computational fluid dynamics simulations
5
作者 Zhehao Dong Zhen Lu Yue Yang 《Theoretical & Applied Mechanics Letters》 2025年第3期219-225,共7页
Configuring computational fluid dynamics(CFD)simulations typically demands extensive domain expertise,limiting broader access.Although large language models(LLMs)have advanced scientific computing,their use in automat... Configuring computational fluid dynamics(CFD)simulations typically demands extensive domain expertise,limiting broader access.Although large language models(LLMs)have advanced scientific computing,their use in automating CFD workflows is underdeveloped.We introduce a novel approach centered on domain-specific LLM adaptation.By fine-tuning Qwen2.5-7B-Instruct on NL2FOAM,our custom dataset of 28,716 natural language-to-OpenFOAM configuration pairs with chain-of-thought(CoT)annotations enables direct translation from natural language descriptions to executable CFD setups.A multi-agent system orchestrates the process,autonomously verifying inputs,generating configurations,running simulations,and correcting errors.Evaluation on a benchmark of 21 diverse flow cases demonstrates state-of-the-art performance,achieving 88.7%solution accuracy and 82.6%first-attempt success rate.This significantly outperforms larger general-purpose models such as Qwen2.5-72B-Instruct,DeepSeek-R1,and Llama3.3-70B-Instruct,while also requiring fewer correction iterations and maintaining high computational efficiency.The results highlight the critical role of domain-specific adaptation in deploying LLM assistants for complex engineering workflows.Our code and fine-tuned model have been deposited at https://github.com/YYgroup/AutoCFD. 展开更多
关键词 Large language models Fine-tuning Computational fluid dynamics Automated CFD multi-agent system
在线阅读 下载PDF
Model Design and Simulation of an 80 kW Capacitor Coupled Substation Derived from a 132 kV Transmission Line
6
作者 Sinqobile Wiseman Nene Bolanle Tolulope Abe Agha Francis Nnachi 《Open Journal of Modelling and Simulation》 2025年第1期1-19,共19页
The global rise in energy demand, particularly in remote and sparsely populated regions, necessitates innovative and cost-effective electrical distribution solutions. Traditional Rural Electrification (RE) methods, li... The global rise in energy demand, particularly in remote and sparsely populated regions, necessitates innovative and cost-effective electrical distribution solutions. Traditional Rural Electrification (RE) methods, like Conventional Rural Electrification (CRE), have proven economically unfeasible in such areas due to high infrastructure costs and low electricity demand. Consequently, Unconventional Rural Electrification (URE) technologies, such as Capacitor Coupled Substations (CCS), are gaining attention as viable alternatives. This study presents the design and simulation of an 80 kW CCS system, which taps power directly from a 132 kV transmission line to supply low-voltage consumers. The critical components of the CCS, the capacitors are calculated, then a MATLAB/Simulink model with the attained results is executed. Mathematical representation and state-space representation for maintaining the desired tapped voltage area also developed. The research further explores the feasibility and operational performance of this CCS configuration, aiming to address the challenges of rural electrification by offering a sustainable and scalable solution. The results show that the desired value of the tapped voltage can be achieved at any level of High Voltage (HV) with the selection of capacitors that are correctly rated. With an adequately designed control strategy, the research also shows that tapped voltage can be attained under both steady-state and dynamic loads. By leveraging CCS technology, the study demonstrates the potential for delivering reliable electricity to underserved areas, highlighting the system’s practicality and effectiveness in overcoming the limitations of conventional distribution methods. 展开更多
关键词 Capacitor-Coupled Substation Transmission Line-linked Capacitor-Coupled Substation Capacitor-Coupled Substation simulation MICROGRIDS Rural Electrification Power System modeling
在线阅读 下载PDF
Numerical simulation of 3D supersonic asymmetric truncated nozzle based on k-kL algebraic stress model
7
作者 Gang WANG Shuai ZHANG +1 位作者 Jifa ZHANG Yao ZHENG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 2025年第3期238-251,共14页
The nozzle is a critical component responsible for generating most of the net thrust in a scramjet engine.The quality of its design directly affects the performance of the entire propulsion system.However,most turbule... The nozzle is a critical component responsible for generating most of the net thrust in a scramjet engine.The quality of its design directly affects the performance of the entire propulsion system.However,most turbulence models struggle to make accurate predictions for subsonic and supersonic flows in nozzles.In this study,we explored a novel model,the algebraic stress model k-kL-ARSM+J,to enhance the accuracy of turbulence numerical simulations.This new model was used to conduct numerical simulations of the design and off-design performance of a 3D supersonic asymmetric truncated nozzle designed in our laboratory,with the aim of providing a realistic pattern of changes.The research indicates that,compared to linear eddy viscosity turbulence models such as k-kL and shear stress transport(SST),the k-kL-ARSM+J algebraic stress model shows better accuracy in predicting the performance of supersonic nozzles.Its predictions were identical to the experimental values,enabling precise calculations of the nozzle.The performance trends of the nozzle are as follows:as the inlet Mach number increases,both thrust and pitching moment increase,but the rate of increase slows down.Lift peaks near the design Mach number and then rapidly decreases.With increasing inlet pressure,the nozzle thrust,lift,and pitching moment all show linear growth.As the flight altitude rises,the internal flow field within the nozzle remains relatively consistent due to the same supersonic nozzle inlet flow conditions.However,external to the nozzle,the change in external flow pressure results in the nozzle exit transitioning from over-expanded to under-expanded,leading to a shear layer behind the nozzle that initially converges towards the nozzle center and then diverges. 展开更多
关键词 Supersonic nozzle Turbulence model Numerical simulation Performance analysis
原文传递
Tropical Cyclone Simulations:The Impact of Model Top/Damping Layer and the Role of Stratospheric Gravity Waves
8
作者 Xu WANG Yuan WANG +2 位作者 Lifeng ZHANG Yun ZHANG Jiping GUAN 《Advances in Atmospheric Sciences》 2025年第11期2290-2304,共15页
This paper investigates the impact of the model top and damping layer on the numerical simulation of tropical cyclones(TCs)and reveals the significant role of stratospheric gravity waves(SGWs).TCs can generate SGWs,wh... This paper investigates the impact of the model top and damping layer on the numerical simulation of tropical cyclones(TCs)and reveals the significant role of stratospheric gravity waves(SGWs).TCs can generate SGWs,which propagate upward and outward into the stratosphere.These SGWs can reach the damping layer,which is a consequence of the numerical scheme employed,where they can affect the tangential circulation through the dragging and forcing processes.In models with a higher top boundary,this tangential circulation develops far from the TC and has minimal direct impact on TC intensity.By comparison,in models with a lower top(e.g.,20 km),the damping layer is located just above the top of the TC.The SGW dragging in the damping layer and the consequent tangential force can thus induce ascent outside the eyewall,promote latent heat release,tilt the eyewall,and enlarge the inner-core radius.This process will reduce inner-core vorticity advection within the boundary layer,and eventually inhibits the intensification of the TC.This suggests that when the thickness of the damping layer is 5 km,the TC numerical model top height should be at least higher than 20 km to generate more accurate simulations. 展开更多
关键词 gravity waves STRATOSPHERE tropical cyclones numerical simulations damping layer model top
在线阅读 下载PDF
Multi-scale Numerical Simulations for Crack Propagation in NiTi Shape Memory Alloys by Molecular Dynamics-based Cohesive Zone Model
9
作者 LI Yunfei WANG Yuancen HE Qinshu 《Journal of Wuhan University of Technology(Materials Science)》 2025年第2期599-609,共11页
The multi-scale modeling combined with the cohesive zone model(CZM)and the molecular dynamics(MD)method were preformed to simulate the crack propagation in NiTi shape memory alloys(SMAs).The metallographic microscope ... The multi-scale modeling combined with the cohesive zone model(CZM)and the molecular dynamics(MD)method were preformed to simulate the crack propagation in NiTi shape memory alloys(SMAs).The metallographic microscope and image processing technology were employed to achieve a quantitative grain size distribution of NiTi alloys so as to provide experimental data for molecular dynamics modeling at the atomic scale.Considering the size effect of molecular dynamics model on material properties,a reasonable modeling size was provided by taking into account three characteristic dimensions from the perspective of macro,meso,and micro scales according to the Buckinghamπtheorem.Then,the corresponding MD simulation on deformation and fracture behavior was investigated to derive a parameterized traction-separation(T-S)law,and then it was embedded into cohesive elements of finite element software.Thus,the crack propagation behavior in NiTi alloys was reproduced by the finite element method(FEM).The experimental results show that the predicted initiation fracture toughness is in good agreement with experimental data.In addition,it is found that the dynamics initiation fracture toughness increases with decreasing grain size and increasing loading velocity. 展开更多
关键词 NiTi shape memory alloys multi-scale numerical simulation crack propagation the cohesive zone model molecular dynamics simulation
原文传递
A prediction model for guiding tumor microwave ablation surgery based on simulation
10
作者 Lu Qian Yamin Yang +4 位作者 Pan Chen Jia Liu Xiaofei Jin Zhiyu Qian Chunxiao Chen 《Journal of Innovative Optical Health Sciences》 2025年第1期85-99,共15页
Purpose:The major limitation of tumor microwave ablation(MWA)operation is the lack of predictability of the ablation zone before surgery.Operators rely on their individual experience to select a treatment plan,which i... Purpose:The major limitation of tumor microwave ablation(MWA)operation is the lack of predictability of the ablation zone before surgery.Operators rely on their individual experience to select a treatment plan,which is prone to either inadequate or excessive ablation.This paper aims to establish an ablation prediction model that guides MWA tumor surgical planning.Methods:An MWA process was first simulated by incorporating electromagnetic radiation equations,thermal equations,and optimized biological tissue parameters(dynamic dielectric and thermophysical parameters).The temperature distributions(the short/long diameters,and the total volume of the ablation zone)were then generated and verified by 60 cases ex vivo porcine liver experiments.Subsequently,a series of data were obtained from the simulated temperature distributions and to further fit the novel ablation coagulated area prediction model(ACAPM),thus rendering the ablation-dose table for the guiding surgical plan.The MWA clinical patient data and clinical devices suggested data were used to validate the accuracy and practicability of the established predicted model.Results:The 60 cases ex vivo porcine liver experiments demonstrated the accuracy of the simulated temperature distributions.Compared to traditional simulation methods,our approach reduces the long-diameter error of the ablation zone from 1.1 cm to 0.29 cm,achieving a 74%reduction in error.Further,the clinical data including the patients'operation results and devices provided values were consistent well with our predicated data,indicating the great potential of ACAPM to assist preoperative planning. 展开更多
关键词 Microwave ablation ablation simulation microwave prediction model dynamic tissue parameter
原文传递
Differential adsorption characteristics in the composite model of deep marine shale:Implication from molecular dynamics simulations
11
作者 Yu-Ying Wang Jun-Qing Chen +8 位作者 Fu-Jie Jiang Xiao-Bin Yang Xiao Zhang Hong Pang Dong-Xia Chen Bing-Yao Li Xin-Yi Niu Gui-Li Ma Kan-Yuan Shi 《Petroleum Science》 2025年第6期2247-2261,共15页
Shale gas serves as a significant strategic successor resource for future oil and gas reserves and production in China.Thus,a profound understanding of the adsorption mechanism of shale gas in shale reservoirs is cruc... Shale gas serves as a significant strategic successor resource for future oil and gas reserves and production in China.Thus,a profound understanding of the adsorption mechanism of shale gas in shale reservoirs is crucial to accurately predict and evaluate shale gas reserves.In this study,we utilized two simulation methods,molecular dynamics simulation and Giant Canonical Monte Carlo simulation to examine the adsorption characteristics of kerogen under varying temperature and pressure conditions.We compared the results under identical temperature and pressure conditions for different mineral-kerogen composite models.Moreover,we examined the effects of temperature,pressure,and mineral species on the kerogen adsorption mechanism.The results indicate that shale formations with high organic matter content and a substantial proportion of non-clay inorganic minerals,as well as those subjected to higher temperature and pressure conditions than the shallow layer,possess a greater capacity to accommodate shale gas.This study examined the adsorption mechanism of methane in shale gas using different mineral-kerogen composite models.The findings of this study provide more accurate guidance and support for efficient development of shale gas. 展开更多
关键词 Adsorption mechanisms Kerogen model Longmaxi Formation Marine shale molecular simulation Shale gas
原文传递
PM_(10) dust emission in the Erenhot-Huailai zone of northern China based on model simulation
12
作者 WANG Yong YAN Ping +3 位作者 WU Wei WANG Yijiao HU Chanjuan LI Shuangquan 《Journal of Arid Land》 2025年第3期324-336,共13页
The Erenhot-Huailai zone, as an important dust emission source area in northern China, affects the air quality of Beijing City, Tianjin City, and Hebei Province and human activities in this zone have a profound impact... The Erenhot-Huailai zone, as an important dust emission source area in northern China, affects the air quality of Beijing City, Tianjin City, and Hebei Province and human activities in this zone have a profound impact on surface dust emission. In order to explore the main source areas of surface dust emission and quantify the impacts of human activities on surface dust emission, we investigated the surface dust emission of different land types on the Erenhot-Huailai zone by model simulation, field observation, and comparative analysis. The results showed that the average annual inhalable atmospheric particles(PM_(10)) dust emission fluxes in arid grassland, Hunshandake Sandy Land, semi-arid grassland,semi-arid agro-pastoral area, dry sub-humid agro-pastoral area, and semi-humid agro-pastoral area were 4.41, 0.71, 3.64, 1.94, 0.24, and 0.14 t/hm^(2), respectively, and dust emission in these lands occurred mainly from April to May. Due to the influence of human activities on surface dust emission, dust emission fluxes from different land types were 1.66–4.41 times greater than those of their background areas, and dust emission fluxes from the main dust source areas were 1.66–3.89 times greater than those of their background areas. According to calculation, the amount of PM_(10) dust emission influenced by human disturbance accounted for up to 58.00% of the total dust emission in the study area. In addition, the comparative analysis of model simulation and field observation results showed that the simulated and observed dust emission fluxes were relatively close to each other, with differences ranging from 0.01 to 0.21 t/hm^(2) in different months, which indicated that the community land model version 4.5(CLM4.5) had a high accuracy. In conclusion, model simulation results have important reference significance for identifying dust source areas and quantifying the contribution of human activities to surface dust emission. 展开更多
关键词 northern China classification of land type model simulation dust emission human disturbance
在线阅读 下载PDF
A Connectivity Model for the Numerical Simulation of Microgel Flooding in Low-Permeability Reservoirs
13
作者 Tao Wang Haiyang Yu +5 位作者 Jie Gao Fei Wang Xinlong Zhang Hao Yang Guirong Di Pengrun Wang 《Fluid Dynamics & Materials Processing》 2025年第5期1191-1200,共10页
Oilfields worldwide are increasingly grappling with challenges such as early water breakthrough and high water production,yet direct,targeted solutions remain elusive.In recent years,chemical flooding techniques desig... Oilfields worldwide are increasingly grappling with challenges such as early water breakthrough and high water production,yet direct,targeted solutions remain elusive.In recent years,chemical flooding techniques designed for tertiary oil recovery have garnered significant attention,with microgel flooding emerging as a particularly prominent area of research.Despite its promise,the complex mechanisms underlying microgel flooding have been rarely investigated numerically.This study aims to address these gaps by characterizing the distribution of microgel concentration and viscosity within different pore structures.To enhance the accuracy of these characterizations,the viscosity of microgels is adjusted to account for the shear effects induced by flow rate and the swelling effects driven by salinity variations.The absolute permeability of the rock and the relative permeability of both oil and microgel are also analyzed to elucidate the mechanisms of microgel flooding.Additionally,a connectivity model is employed to achieve a quantitative representation of fluid flow capacity.The proposed model is validated through conceptual examples and applied to real oilfield blocks,demonstrating its accuracy and practical applicability. 展开更多
关键词 Connectivity model chemical enhanced oil recovery microgel flooding numerical reservoir simulation fractured reservoirs
在线阅读 下载PDF
UAF-based integration of design and simulation model for system-of-systems
14
作者 FENG Yimin GE Ping +2 位作者 SHAO Yanli ZOU Qiang LIU Yusheng 《Journal of Systems Engineering and Electronics》 2025年第1期108-126,共19页
Model-based system-of-systems(SOS)engineering(MBSoSE)is becoming a promising solution for the design of SoS with increasing complexity.However,bridging the models from the design phase to the simulation phase poses si... Model-based system-of-systems(SOS)engineering(MBSoSE)is becoming a promising solution for the design of SoS with increasing complexity.However,bridging the models from the design phase to the simulation phase poses significant challenges and requires an integrated approach.In this study,a unified requirement modeling approach is proposed based on unified architecture framework(UAF).Theoretical models are proposed which compose formalized descriptions from both topdown and bottom-up perspectives.Based on the description,the UAF profile is proposed to represent the SoS mission and constituent systems(CS)goal.Moreover,the agent-based simulation information is also described based on the overview,design concepts,and details(ODD)protocol as the complement part of the SoS profile,which can be transformed into different simulation platforms based on the eXtensible markup language(XML)technology and model-to-text method.In this way,the design of the SoS is simulated automatically in the early design stage.Finally,the method is implemented and an example is given to illustrate the whole process. 展开更多
关键词 model-based systems engineering unified architecture framework(UAF) system-of-systems engineering model transformation simulation
在线阅读 下载PDF
A conductivity model for hydrogen based on ab initio simulations
15
作者 Uwe Kleinschmidt Ronald Redmer 《Matter and Radiation at Extremes》 2025年第4期58-69,共12页
We calculate the electrical and thermal conductivity of hydrogen for a wide range of densities and temperatures by using molecular dynamics simulations informed by density functional theory.On the basis of the corresp... We calculate the electrical and thermal conductivity of hydrogen for a wide range of densities and temperatures by using molecular dynamics simulations informed by density functional theory.On the basis of the corresponding extended ab initio data set,we construct interpolation formulas covering the range from low-density,high-temperature to high-density,low-temperature plasmas.Our conductivity model repro-duces the well-known limits of the Spitzer and Ziman theory.We compare with available experimental data andfind very good agreement.The new conductivity model can be applied,for example,in dynamo simulations for magneticfield generation in gas giant planets,brown dwarfs,and stellar envelopes. 展开更多
关键词 molecular dynamics simulations electrical thermal conductivity CONDUCTIVITY density functional theoryon interpolation formulas conductivity model extended ab initio data setwe spitzer ziman theorywe
在线阅读 下载PDF
Complex adaptive system theory,agent-based modeling,and simulation in dominant technology formation 被引量:1
16
作者 ZHANG Ruihan SUN Bing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2024年第1期130-153,共24页
Dominant technology formation is the key for the hightech industry to“cross the chasm”and gain an established foothold in the market(and hence disrupt the regime).Therefore,a stimulus-response model is proposed to i... Dominant technology formation is the key for the hightech industry to“cross the chasm”and gain an established foothold in the market(and hence disrupt the regime).Therefore,a stimulus-response model is proposed to investigate the dominant technology by exploring its formation process and mechanism.Specifically,based on complex adaptive system theory and the basic stimulus-response model,we use a combination of agent-based modeling and system dynamics modeling to capture the interactions between dominant technology and the socio-technical landscape.The results indicate the following:(i)The dynamic interaction is“stimulus-reaction-selection”,which promotes the dominant technology’s formation.(ii)The dominant technology’s formation can be described as a dynamic process in which the adaptation intensity of technology standards increases continuously until it becomes the leading technology under the dual action of internal and external mechanisms.(iii)The dominant technology’s formation in the high-tech industry is influenced by learning ability,the number of adopting users and adaptability.Therein,a“critical scale”of learning ability exists to promote the formation of leading technology:a large number of adopting users can promote the dominant technology’s formation by influencing the adaptive response of technology standards to the socio-technical landscape and the choice of technology standards by the socio-technical landscape.There is a minimum threshold and a maximum threshold for the role of adaptability in the dominant technology’s formation.(iv)The socio-technical landscape can promote the leading technology’s shaping in the high-tech industry,and different elements have different effects.This study promotes research on the formation mechanism of dominant technology in the high-tech industry,presents new perspectives and methods for researchers,and provides essential enlightenment for managers to formulate technology strategies. 展开更多
关键词 complex adaptive system theory agent-based modeling and simulation dominant technology socio-technical landscape adaptation-choice
在线阅读 下载PDF
Two Monte Carlo-based simulators for imaging-system modeling and projection simulation of flat-panel X-ray source
17
作者 Meng-Ke Qi Ting He +7 位作者 Yi-Wen Zhou Jing Kang Zeng-Xiang Pan Song Kang Wang-Jiang Wu Jun Chen Ling-Hong Zhou Yuan Xu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第7期31-46,共16页
The advantages of a flat-panel X-ray source(FPXS)make it a promising candidate for imaging applications.Accurate imaging-system modeling and projection simulation are critical for analyzing imaging performance and res... The advantages of a flat-panel X-ray source(FPXS)make it a promising candidate for imaging applications.Accurate imaging-system modeling and projection simulation are critical for analyzing imaging performance and resolving overlapping projection issues in FPXS.The conventional analytical ray-tracing approach is limited by the number of patterns and is not applicable to FPXS-projection calculations.However,the computation time of Monte Carlo(MC)simulation is independent of the size of the patterned arrays in FPXS.This study proposes two high-efficiency MC projection simulators for FPXS:a graphics processing unit(GPU)-based phase-space sampling MC(gPSMC)simulator and GPU-based fluence sampling MC(gFSMC)simulator.The two simulators comprise three components:imaging-system modeling,photon initialization,and physical-interaction simulations in the phantom.Imaging-system modeling was performed by modeling the FPXS,imaging geometry,and detector.The gPSMC simulator samples the initial photons from the phase space,whereas the gFSMC simulator performs photon initialization from the calculated energy spectrum and fluence map.The entire process of photon interaction with the geometry and arrival at the detector was simulated in parallel using multiple GPU kernels,and projections based on the two simulators were calculated.The accuracies of the two simulators were evaluated by comparing them with the conventional analytical ray-tracing approach and acquired projections,and the efficiencies were evaluated by comparing the computation time.The results of simulated and realistic experiments illustrate the accuracy and efficiency of the proposed gPSMC and gFSMC simulators in the projection calculation of various phantoms. 展开更多
关键词 Flat-panel X-ray source(FPXS) Imaging-system modeling Projection simulation Monte Carlo-based simulators
在线阅读 下载PDF
Novel Sum-of-Sinusoids Simulation Channel Modeling for 6G Multiple-Input Multiple-Output Vehicle-to-Everything Communications
18
作者 Hao Jiang Hongming Zhang Ting Liu 《China Communications》 SCIE CSCD 2024年第1期242-259,共18页
In this paper,a statistical cluster-based simulation channel model with a finite number of sinusoids is proposed for depicting the multiple-input multiple-output(MIMO)communications in vehicleto-everything(V2X)environ... In this paper,a statistical cluster-based simulation channel model with a finite number of sinusoids is proposed for depicting the multiple-input multiple-output(MIMO)communications in vehicleto-everything(V2X)environments.In the proposed sum-of-sinusoids(SoS)channel model,the waves that emerge from the transmitter undergo line-of-sight(LoS)and non-line-of-sight(NLoS)propagation to the receiver,which makes the model suitable for describing numerous V2X wireless communication scenarios for sixth-generation(6G).We derive expressions for the real and imaginary parts of the complex channel impulse response(CIR),which characterize the physical propagation characteristics of V2X wireless channels.The statistical properties of the real and imaginary parts of the complex CIRs,i.e.,autocorrelation functions(ACFs),Doppler power spectral densities(PSDs),cross-correlation functions(CCFs),and variances of ACFs and CCFs,are derived and discussed.Simulation results are generated and match those predicted by the underlying theory,demonstrating the accuracy of our derivation and analysis.The proposed framework and underlying theory arise as an efficient tool to investigate the statistical properties of 6G MIMO V2X communication systems. 展开更多
关键词 complex CIRs LoS and NLoS propagation components MIMO V2X communication environments SoS simulation channel model statistical properties
在线阅读 下载PDF
Application of Modelica Based Multi- Domain Modeling and Simulation for Gravity-1
19
作者 ZHANG Chi BU Xiangwei +3 位作者 XU Lijie WU Kao HOU Shiyuan XU Guoguang 《Aerospace China》 2024年第1期47-55,共9页
In the R&D phase of Gravity-1(YL-1), a multi-domain modeling and simulation technology based on Modelica language was introduced, which was a recent attempt in the practice of modeling and simulation method for la... In the R&D phase of Gravity-1(YL-1), a multi-domain modeling and simulation technology based on Modelica language was introduced, which was a recent attempt in the practice of modeling and simulation method for launch vehicles in China. It realizes a complex coupling model within a unified model for different domains, so that technologists can work on one model. It ensured the success of YL-1 first launch mission, supports rapid iteration, full validation, and tight design collaboration. 展开更多
关键词 modelICA Gravity-1 simulation modeling launch vehicle model
在线阅读 下载PDF
Discrete decision model and multi-agent simulation of the Liang Zong two-chain hierarchical organization in a complex project
20
作者 MAI Qiang ZHAO Yueqiang AN Shi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第2期311-320,共10页
Different from the organization structure of complex projects in Western countries, the Liang Zong hierarchical organization structure of complex projects in China has two different chains, the chief-engineer chain an... Different from the organization structure of complex projects in Western countries, the Liang Zong hierarchical organization structure of complex projects in China has two different chains, the chief-engineer chain and the general-director chain,to handle the trade-off between technical and management decisions. However, previous works on organization search have mainly focused on the single-chain hierarchical organization in which all decisions are regarded as homogeneous. The heterogeneity and the interdependency between technical decisions and management decisions have been neglected. A two-chain hierarchical organization structure mapped from a real complex project is constructed. Then, a discrete decision model for a Liang Zong two-chain hierarchical organization in an NK model framework is proposed. This model proves that this kind of organization structure can reduce the search space by a large amount and that the search process should reach a final stable state more quickly. For a more complicated decision mechanism, a multi-agent simulation based on the above NK model is used to explore the effect of the two-chain organization structure on the speed, stability, and performance of the search process. The results provide three insights into how, compared with the single-chain hierarchical organization, the two-chain organization can improve the search process: it can reduce the number of iterations efficiently; the search is more stable because the search space is a smoother hill-like fitness landscape; in general, the search performance can be improved.However, when the organization structure is very complicated, the performance of a two-chain organization is inferior to that of a single-chain organization. These findings about the efficiency of the unique Chinese-style organization structure can be used to guide organization design for complex projects. 展开更多
关键词 complex project two-chain hierarchical organization discrete decision model multi-agent simulation
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部