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
Computer simulation models may by used to gain further information about missile performance variability. Model validation is an important aspect of the test program for a missile system. Validation provides a basis f...Computer simulation models may by used to gain further information about missile performance variability. Model validation is an important aspect of the test program for a missile system. Validation provides a basis for confidence in the model's results and is a necessary step if the model is to be used to draw inference about the behavior of the real missile. This paper is a review of methods useful for validation of computer simulation models of missile systems and provides a new method with high degree of confidence for validation of computer simulation models of missile systems. Some examples of the use of the new method in validating computer simulation models are given.展开更多
Widespread implementation of electronic health records has led to the increased use of artificial intelligence(AI)and computer modeling in clinical medicine.The early recognition and treatment of critical illness are ...Widespread implementation of electronic health records has led to the increased use of artificial intelligence(AI)and computer modeling in clinical medicine.The early recognition and treatment of critical illness are central to good outcomes but are made difficult by,among other things,the complexity of the environment and the often non-specific nature of the clinical presentation.Increasingly,AI applications are being proposed as decision supports for busy or distracted clinicians,to address this challenge.Data driven“associative”AI models are built from retrospective data registries with missing data and imprecise timing.Associative AI models lack transparency,often ignore causal mechanisms,and,while potentially useful in improved prognostication,have thus far had limited clinical applicability.To be clinically useful,AI tools need to provide bedside clinicians with actionable knowledge.Explicitly addressing causal mechanisms not only increases validity and replicability of the model,but also adds transparency and helps gain trust from the bedside clinicians for real world use of AI models in teaching and patient care.展开更多
Objective: To explore the effectiveness of applying patient simulators combined with Internet Plus scenario simulation teaching models on intravenous (IV) infusion nursing education, and to provide scientific evidence...Objective: To explore the effectiveness of applying patient simulators combined with Internet Plus scenario simulation teaching models on intravenous (IV) infusion nursing education, and to provide scientific evidence for the implementation of advanced teaching models in future nursing education. Methods: Enrolled 60 nurses who took the IV infusion therapy training program in our hospital from January 2022 to December 2023 for research. 30 nurses who were trained in traditional teaching models from January to December 2022 were selected as the control group, and 30 nurses who were trained with simulation-based teaching models with methods including simulated patients, internet, online meetings which can be replayed and scenario simulation, etc. from January to December 2023 were selected as the experimental group. Evaluated the learning outcomes based on the Competency Inventory for Nursing Students (CINS), Problem-Solving Inventory (PSI), comprehensive learning ability, scientific research ability, and proficiency in the theoretical knowledge and practical skills of IV infusion therapy. Nursing quality, the incidence of IV infusion therapy complications and nurse satisfaction with different teaching models were also measured. Results: The scientific research ability, PSI scores, CINS scores, and comprehensive learning ability of the experimental group were better than those of the control group (P 0.05), and their assessment results of practical skills, nursing quality of IV infusion therapy during training, and satisfaction with teaching models were all better than those of the control group with statistical significance (P < 0.05). The incidence of IV infusion therapy complications in the experimental group was lower than that in the control group, indicating statistical significance (P < 0.05). Conclusions: Teaching models based on patient simulators combined with Internet Plus scenario simulation enable nursing students to learn more directly and practice at any time and in any place, and can improve their proficiency in IV infusion theoretical knowledge and skills (e.g. PICC catheterization), core competencies, problem-solving ability, comprehensive learning ability, scientific research ability and the ability to deal with complicated cases. Also, it helps provide high-quality nursing education, improve the nursing quality of IV therapy, reduce the incidence of related complications, and ensure the safety of patients with IV therapy.展开更多
There is a close relationship between agricultural production and environmental meteorological conditions. In the study of the correlation between them, the simulation models are paid more attention to the crop growth...There is a close relationship between agricultural production and environmental meteorological conditions. In the study of the correlation between them, the simulation models are paid more attention to the crop growth. In this paper the development of the studies on the crop growth dynamic simulation model in China is briefly reviewed. The relationships between meteorological conditions and each process of crop growth (such as photosynthesis, respiration, accumulation and distribution of assimilation products and growth of leaf area) are studied and simulated basing on the results from field experiments. Preliminary models for rice, wheat, maize and soybean have been developed, and some investigations about modelling methods, procedures and parameters in simulation models are made.展开更多
Automotive manufacturing is complex and includes the coordination of design in the manufacturing system. The manufacturing approaches over the past few years, disassembly have been a key issue, and it seems that simul...Automotive manufacturing is complex and includes the coordination of design in the manufacturing system. The manufacturing approaches over the past few years, disassembly have been a key issue, and it seems that simulation models are usually tailored to address a narrow set of industrial issues. This paper describes the development of the production line in the automobile manufacturing system through design, operation, and maintenance, based on multi-objectives of Algorithm and Simulation Model called MOA-SM. The both models are being developed at three different levels： the production line in the body and assembly shop, supply chain, and the production plan. The optimization tries to involve more objectives to solve the issues in manufacturing system. A solution that may optimize one performance measure may deteriorate since other performance solutions are difficult. The resulting algorithms are comparable to the simulation and multi-object in terms of success rate, assembly times, peak forces, moments, and have assembly times superior to those of a benchmark blind search algorithm.展开更多
The aim of this paper is to present graphically the behaviour of a simulation model to the varying parameters and to establish the suitability of this representation as a valid tool for the analysis of the same parame...The aim of this paper is to present graphically the behaviour of a simulation model to the varying parameters and to establish the suitability of this representation as a valid tool for the analysis of the same parameters. In this paper, we define parameter combinatorial diagram as the joint graphical representation of all box plots related to the adjustment between real and simulated data, by setting and/or changing the parameters of the simulation model. To do this, we start with a box plot representing the values of an objective adjustment function, achieving these results when varying all the parameters of the simulation model, Then we draw the box plot when setting all the parameters of the model, for example, using the median or average. Later, we get all the box plots when carrying out simulations combining fixed or variable values of the model parameters. Finally, all box plots obtained are represented neatly in a single graph. It is intended that the new parameter combinatorial diagram is used to examine and analyze simulation models useful in practice. This paper presents combinatorial diagrams of different examples of application as in the case of hydrologic models of one, two, three, and five parameters.展开更多
Leveraging digital technology for effective decision making requires tools that can comprehend detailed complex process of healthcare organizations. Considering all dimensions, simulation is applicable in many ways th...Leveraging digital technology for effective decision making requires tools that can comprehend detailed complex process of healthcare organizations. Considering all dimensions, simulation is applicable in many ways throughout the healthcare system due to its ability to capture and mimic detail complexity in clinical operations decisions. Healthcare simulation not only helps ensure that providing services of the highest quality, but simulation ultimately increases the ability of following best practices, quality improvement, and risk management activities. Moreover, this representation of healthcare system has become a primary tool by which increased patient safety can be integrated and facilitated into clinical practices. This article presents a simulation model for healthcare outpatient clinics. This model aims to aid in setting up management guidelines and propose procedure to improve the operation of the clinics and to optimize the performance of such dynamic healthcare clinic. Model optimization is used to find out the optimal staff as resources, which includes physician, nurses, and clinics minimize patient length of stay and smooth patient flow.展开更多
Among various power system disturbances,cascading failures are considered the most serious and extreme threats to grid operations,potentially leading to significant stability issues or even widespread power blackouts....Among various power system disturbances,cascading failures are considered the most serious and extreme threats to grid operations,potentially leading to significant stability issues or even widespread power blackouts.Simulating power systems’behaviors during cascading failures is of great importance to comprehend how failures originate and propagate,as well as to develop effective preventive and mitigative control strategies.The intricate mechanism of cascading failures,characterized by multi-timescale dynamics,presents exceptional challenges for their simulations.This paper provides a comprehensive review of simulation models for cascading failures,providing a systematic categorization and a comparison of these models.The challenges and potential research directions for the future are also discussed.展开更多
In recent years,rapid urbanization has had a profound impact on landscape stability.As a typical example of China's rapid urbanization,Hangzhou has also experienced significant landscape changes,which have profoun...In recent years,rapid urbanization has had a profound impact on landscape stability.As a typical example of China's rapid urbanization,Hangzhou has also experienced significant landscape changes,which have profoundly affected its ecological stability.Taking Hangzhou as an example,this study integrates land use change data from 1980 to 2020,combines dynamic simulation and ecological modeling techniques,and carries out a comprehensive analysis of historical trends and future predictions,to provide valuable insights into the complex interactions between urban expansion and landscape stability.The results indicate that:1)between 1980 and2020,Hangzhou experienced a significant increase in construction land at the expense of arable land,leading to a gradual decline in landscape stability,though the downward trend has slowed in recent years.2)The spatial distribution of landscape stability shows clear aggregation patterns,with lower stability concentrated in economically active flatlands and higher stability in the mountainous western regions.3)By 2040,further urban expansion is predicted to occur alongside increased landscape integration,reflecting the positive effects of ecological protection strategies.This study highlights the universal challenges of balancing economic growth with ecological stability in rapidly urbanizing regions.The combination of advanced simulation models and spatiotemporal analysis demonstrates a replicable framework for assessing urban expansion's ecological impacts.These findings underscore the importance of tailoring urban planning and ecological policies to address regional disparities,providing valuable insights for sustainable urban development and landscape management globally.展开更多
Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and t...Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and temporal change characteristics of ecological network and analyzing the integrated relationship between LUCC and ecological security are crucial for ensuring regional ecological security.Gansu is one of the provinces with fragile ecological environment in China,and rapid changes in land use patterns in recent decades have threatened ecological security.Therefore,taking Gansu Province as the study area,this study simulated its land use pattern in 2050 using patch-generating land use simulation(PLUS)model based on the LUCC trend from 2000 to 2020 and integrated the LUCC into morphological spatial pattern analysis(MSPA)to identify ecological sources and extract the ecological corridors to construct ecological network using circuit theory.The results revealed that,according to the prediction results in 2050,the areas of cultivated land,forest land,grassland,water body,construction land,and unused land would be 63,447.52,39,510.80,148,115.18,4605.21,8368.89,and 161,752.40 km^(2),respectively.The number of ecological sources in Gansu Province would increase to 80,with a total area of 99,927.18 km^(2).The number of ecological corridors would increase to 191,with an estimated total length of 6120.66 km.Both ecological sources and ecological corridors showed a sparse distribution in the northwest and dense distribution in the southeast of the province at the spatial scale.The number of ecological pinch points would reach 312 and the total area would expect to increase to 842.84 km^(2),with the most pronounced increase in the Longdong region.Compared with 2020,the number and area of ecological barriers in 2050 would decrease significantly by 63 and 370.71 km^(2),respectively.In general,based on the prediction results,the connectivity of ecological network of Gansu Province would increase in 2050.To achieve the predicted ecological network in 2050,emphasis should be placed on the protection of cultivated land and ecological land,the establishment of ecological sources in desert areas,the reinforcement of the protection for existing ecological sources,and the construction of ecological corridors to enhance the stability of ecological network.This study provides valuable theoretical support and references for the future construction of ecological networks and regional land resource management decision-making.展开更多
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
AIGaN/GaN HEMTs are investigated by numerical simulation from the self-consistent solution of Schr6dinger-Poisson-hydrodynamic （HD） systems. The influences of polarization charge and quantum effects are considered i...AIGaN/GaN HEMTs are investigated by numerical simulation from the self-consistent solution of Schr6dinger-Poisson-hydrodynamic （HD） systems. The influences of polarization charge and quantum effects are considered in this model. Then the two-dimensional conduction band and electron distribution, electron temperature characteristics, Id versus Vd and Id versus Vg, transfer characteristics and transconductance curves are obtained. Corresponding analysis and discussion based on the simulation results are subsequently given.展开更多
Validating simulation model is one of the important aspects for modeling and simulation. Some methods of validating model are compared and analyzed. Several typical methods, such as TIC’s inequality coefficient, gray...Validating simulation model is one of the important aspects for modeling and simulation. Some methods of validating model are compared and analyzed. Several typical methods, such as TIC’s inequality coefficient, gray interconnected analysis, direct spectrum estimation, maximum entropy spectral estimation based on Burg or Marple, are chosen and programmed in C language. Some examples by using the program are given. The results show that the program is available and it is best to adopt multi methods for validating models.展开更多
The simulation model of the E car HS2000 including the permanent magnetic direct current motor with the augment magnet winding is constructed based on tests in order to simulate the synthetic performance of the elec...The simulation model of the E car HS2000 including the permanent magnetic direct current motor with the augment magnet winding is constructed based on tests in order to simulate the synthetic performance of the electric car. The performance of E car HS2000 is analyzed by means of modeling and programming according to data acquired during tests. The simulation results show that the performance of E car HS2000 is successfully predicted and the model and the corresponding simulation software are feasible for simulating E cars. They can be used as effective tools for analyzing the performance parameters as well as specifications of E cars during prototype stage.展开更多
A deep understanding of crop-water eco-physiological relations is the basis for quantifying plant physiological responses to soil water stress. Pot experiments were conducted to investigate the winter wheat crop-water...A deep understanding of crop-water eco-physiological relations is the basis for quantifying plant physiological responses to soil water stress. Pot experiments were conducted to investigate the winter wheat crop-water relations under both drought and waterlogging conditions in two sequential growing seasons from 2000 to 2002, and then the data were used to develop and validate models simulating the responses of winter wheat growth to drought and waterlogging stress. The experiment consisted of four treatments, waterlogging (keep 1 to 2 cm water layer depth above soil surface), control (70%-80% field capacity), light drought (40%-50% field capacity) and severe drought (30%-40% field capacity) with six replicates at five stages in the 2000-2001 growth season. Three soil water content treatments (waterlogging, control and drought) with two replicates were designed in the 2001-2002 growth season. Waterlogging and control treatments are the same as in the 2000-2001 growth season. For the drought treatment, no water was supplied and the soil moisture decreased from field capacity to wilting point. Leaf net photosynthetic rate, transpiration rate, predawn leaf water potential, soil water potential, soil water content and dry matter weight of individual organs were measured. Based on crop-water eco-physiological relations, drought and waterlogging stress factors for winter wheat growth simulation model were put forward. Drought stress factors integrated soil water availability, the sensitivity of different development stages and the difference between physiological processes (such as photosynthesis, transpiration and partitioning). The quantification of waterlogging stress factor considered different crop species, soil water status, waterlogging days and sensitivity at different growth stages. Data sets from the pot experiments revealed favorable performance reliability for the simulation sub-models with the drought and waterlogging stress factors.展开更多
Since remote sensing can provide information on the actual status of an agricultural crop, the integration between remote sensing data and crop growth simulation models has become an important trend for yield estimati...Since remote sensing can provide information on the actual status of an agricultural crop, the integration between remote sensing data and crop growth simulation models has become an important trend for yield estimation and prediction.The main objective of this research was to combine a rice growth simulation model with remote sensing data to estimate rice grain yield for different growing seasons leading to an assessment of rice yield at regional levels. Integration between NOAA (National Oceanic and Atmospheric Administration) AVHRR (Advanced Very High Resolution Radiometer) data and the rice growth simulation model ORYZA1 to develop a new software, which was named as Rice-SRS Model, resulted in accurate estimates for rice yield in Shaoxing, China, with an estimation error reduced to 1.03% and 0.79% over-estimation and 0.79% under-estimation for early, single and late season rice, respectively. Selecting suitable dates for remote sensing images was an important factor which could influence estimation accuracy. Thus, given the different growing periods for each rice season, four images were needed for early and late rice, while five images were preferable for single season rice.Estimating rice yield using two or three images was possible, however, if images were obtained during the panicle initiation and heading stages.展开更多
The mass configuration of the buoyancy-driven underwater glider is decomposed and defined. The coupling between the glider body and its internal masses is addressed using the energy law. A glider motion model is estab...The mass configuration of the buoyancy-driven underwater glider is decomposed and defined. The coupling between the glider body and its internal masses is addressed using the energy law. A glider motion model is established, and the corresponding simulation program is derived using MATLAB. The characteristics of the glider motion are explored using this program. The simula- tion results show that the basic characteristic of a buoyancy-driven underwater glider is the periodic alternation of downward and upward motions. The glider's spiral motion can be applied to missions in restricted regions. The glider's horizontal velocity, gliding depth and its motion radius in spiral motion can be changed to meet different application purposes by using different glider parameter designs. The simulation also shows that the model is appropriate and the program has strong simulation functions.展开更多
OBJECTIVE To explain the high inter-individual variability and the frequency of exceeding the therapeutic reference range and the laboratory alert level of amisulpride,a popula⁃tion pharmacokinetic model in Chinese pa...OBJECTIVE To explain the high inter-individual variability and the frequency of exceeding the therapeutic reference range and the laboratory alert level of amisulpride,a popula⁃tion pharmacokinetic model in Chinese patients with schizophrenia was built based on therapeu⁃tic drug monitoring data to guide individualized therapy.METHODS Plasma concentration data(330 measurements from 121 patients)were ana⁃lyzed using a nonlinear mixed-effects model⁃ing approach with first-order conditional estima⁃tion with interaction(FOCE I).The concentra⁃tions of amisulpride were detected by HPLC-MS/MS.Age,weight,sex,combination medication history and renal function status were evaluated as main covariates.The model was internally val⁃idated using goodness-of-fit,bootstrap and nor⁃malized prediction distribution error.Recom⁃mended dosage regimens for patients with key covariates were estimated on the basis of Monte Carlo simulations and the established model.RESULTS A one-compartment model with first-order absorption and elimination was found to adequately characterize amisulpride concentra⁃tion in Chinese patients with schizophrenia.The population estimates of the apparent volume of distribution(V/F)and apparent clearance(CL/F)were 12.7 L and 1.12 L·h-1,respectively.Age sig⁃nificantly affected the clearance of amisulpride and the final model was as follow:CL/F=1.04×(AGE/32)-0.624(L·h-1).To avoid exceeding the lab⁃oratory alert level(640μg·L-1),the model-based simulation results showed that the recommended dose of amisulpride was no more than 600 mg per day for patients aged 60 years,800 mg per day for those aged 40 years and 1200 mg per day for those aged 20 years,respectively.CON⁃CLUSION Dosage optimization of amisulpride can be carried out according to age to reduce the risk of adverse reactions.The model can be used as a suitable tool for designing individual⁃ized therapy for Chinese patients with schizo⁃phrenia.展开更多
Using the World Meteorological Organization definition and a threshold-based classification technique,simulations of vortex displacement and split sudden stratospheric warmings(SSWs)are evaluated for four Chinese mode...Using the World Meteorological Organization definition and a threshold-based classification technique,simulations of vortex displacement and split sudden stratospheric warmings(SSWs)are evaluated for four Chinese models(BCC-CSM2-MR,FGOALS-f3-L,FGOALS-g3,and NESM3)from phase 6 of the Coupled Model Intercomparison Project(CMIP6)with the Japanese 55-year reanalysis(JRA-55)as a baseline.Compared with six or seven SSWs in a decade in JRA-55,three models underestimate the SSW frequency by~50%,while NESM3 doubles the SSW frequency.SSWs mainly appear in midwinter in JRA-55,but one-month climate drift is simulated in the models.The composite of splits is stronger than displacements in both the reanalysis and most models due to the longer pulse of positive eddy heat flux before onset of split SSWs.A wavenumber-1-like temperature anomaly pattern(cold Eurasia,warm North America)before onset of displacement SSWs is simulated,but cold anomalies are mainly confined to North America after displacement SSWs.Although the lower tropospheric temperature also displays a wavenumber-1-like pattern before split SSWs,most parts of Eurasia and North America are covered by cold anomalies after split SSWs in JRA-55.The models have different degrees of fidelity for the temperature anomaly pattern before split SSWs,but the wavenumber-2-like temperature anomaly pattern is well simulated after split SSWs.The center of the negative height anomalies in the Pacific sector before SSWs is sensitive to the SSW type in both JRA-55 and the models.A negative North Atlantic Oscillation is simulated after both types of SSWs in the models,although it is only observed for split SSWs.展开更多
基金Aeronautical Science Foundation of China (2006ZA51004)
文摘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.
文摘Computer simulation models may by used to gain further information about missile performance variability. Model validation is an important aspect of the test program for a missile system. Validation provides a basis for confidence in the model's results and is a necessary step if the model is to be used to draw inference about the behavior of the real missile. This paper is a review of methods useful for validation of computer simulation models of missile systems and provides a new method with high degree of confidence for validation of computer simulation models of missile systems. Some examples of the use of the new method in validating computer simulation models are given.
文摘Widespread implementation of electronic health records has led to the increased use of artificial intelligence(AI)and computer modeling in clinical medicine.The early recognition and treatment of critical illness are central to good outcomes but are made difficult by,among other things,the complexity of the environment and the often non-specific nature of the clinical presentation.Increasingly,AI applications are being proposed as decision supports for busy or distracted clinicians,to address this challenge.Data driven“associative”AI models are built from retrospective data registries with missing data and imprecise timing.Associative AI models lack transparency,often ignore causal mechanisms,and,while potentially useful in improved prognostication,have thus far had limited clinical applicability.To be clinically useful,AI tools need to provide bedside clinicians with actionable knowledge.Explicitly addressing causal mechanisms not only increases validity and replicability of the model,but also adds transparency and helps gain trust from the bedside clinicians for real world use of AI models in teaching and patient care.
文摘Objective: To explore the effectiveness of applying patient simulators combined with Internet Plus scenario simulation teaching models on intravenous (IV) infusion nursing education, and to provide scientific evidence for the implementation of advanced teaching models in future nursing education. Methods: Enrolled 60 nurses who took the IV infusion therapy training program in our hospital from January 2022 to December 2023 for research. 30 nurses who were trained in traditional teaching models from January to December 2022 were selected as the control group, and 30 nurses who were trained with simulation-based teaching models with methods including simulated patients, internet, online meetings which can be replayed and scenario simulation, etc. from January to December 2023 were selected as the experimental group. Evaluated the learning outcomes based on the Competency Inventory for Nursing Students (CINS), Problem-Solving Inventory (PSI), comprehensive learning ability, scientific research ability, and proficiency in the theoretical knowledge and practical skills of IV infusion therapy. Nursing quality, the incidence of IV infusion therapy complications and nurse satisfaction with different teaching models were also measured. Results: The scientific research ability, PSI scores, CINS scores, and comprehensive learning ability of the experimental group were better than those of the control group (P 0.05), and their assessment results of practical skills, nursing quality of IV infusion therapy during training, and satisfaction with teaching models were all better than those of the control group with statistical significance (P < 0.05). The incidence of IV infusion therapy complications in the experimental group was lower than that in the control group, indicating statistical significance (P < 0.05). Conclusions: Teaching models based on patient simulators combined with Internet Plus scenario simulation enable nursing students to learn more directly and practice at any time and in any place, and can improve their proficiency in IV infusion theoretical knowledge and skills (e.g. PICC catheterization), core competencies, problem-solving ability, comprehensive learning ability, scientific research ability and the ability to deal with complicated cases. Also, it helps provide high-quality nursing education, improve the nursing quality of IV therapy, reduce the incidence of related complications, and ensure the safety of patients with IV therapy.
文摘There is a close relationship between agricultural production and environmental meteorological conditions. In the study of the correlation between them, the simulation models are paid more attention to the crop growth. In this paper the development of the studies on the crop growth dynamic simulation model in China is briefly reviewed. The relationships between meteorological conditions and each process of crop growth (such as photosynthesis, respiration, accumulation and distribution of assimilation products and growth of leaf area) are studied and simulated basing on the results from field experiments. Preliminary models for rice, wheat, maize and soybean have been developed, and some investigations about modelling methods, procedures and parameters in simulation models are made.
文摘Automotive manufacturing is complex and includes the coordination of design in the manufacturing system. The manufacturing approaches over the past few years, disassembly have been a key issue, and it seems that simulation models are usually tailored to address a narrow set of industrial issues. This paper describes the development of the production line in the automobile manufacturing system through design, operation, and maintenance, based on multi-objectives of Algorithm and Simulation Model called MOA-SM. The both models are being developed at three different levels： the production line in the body and assembly shop, supply chain, and the production plan. The optimization tries to involve more objectives to solve the issues in manufacturing system. A solution that may optimize one performance measure may deteriorate since other performance solutions are difficult. The resulting algorithms are comparable to the simulation and multi-object in terms of success rate, assembly times, peak forces, moments, and have assembly times superior to those of a benchmark blind search algorithm.
文摘The aim of this paper is to present graphically the behaviour of a simulation model to the varying parameters and to establish the suitability of this representation as a valid tool for the analysis of the same parameters. In this paper, we define parameter combinatorial diagram as the joint graphical representation of all box plots related to the adjustment between real and simulated data, by setting and/or changing the parameters of the simulation model. To do this, we start with a box plot representing the values of an objective adjustment function, achieving these results when varying all the parameters of the simulation model, Then we draw the box plot when setting all the parameters of the model, for example, using the median or average. Later, we get all the box plots when carrying out simulations combining fixed or variable values of the model parameters. Finally, all box plots obtained are represented neatly in a single graph. It is intended that the new parameter combinatorial diagram is used to examine and analyze simulation models useful in practice. This paper presents combinatorial diagrams of different examples of application as in the case of hydrologic models of one, two, three, and five parameters.
文摘Leveraging digital technology for effective decision making requires tools that can comprehend detailed complex process of healthcare organizations. Considering all dimensions, simulation is applicable in many ways throughout the healthcare system due to its ability to capture and mimic detail complexity in clinical operations decisions. Healthcare simulation not only helps ensure that providing services of the highest quality, but simulation ultimately increases the ability of following best practices, quality improvement, and risk management activities. Moreover, this representation of healthcare system has become a primary tool by which increased patient safety can be integrated and facilitated into clinical practices. This article presents a simulation model for healthcare outpatient clinics. This model aims to aid in setting up management guidelines and propose procedure to improve the operation of the clinics and to optimize the performance of such dynamic healthcare clinic. Model optimization is used to find out the optimal staff as resources, which includes physician, nurses, and clinics minimize patient length of stay and smooth patient flow.
基金supported by UT-Battelle,LLC under Contract No.DE-AC05-00OR22725 with the U.S.Department of Energy.
文摘Among various power system disturbances,cascading failures are considered the most serious and extreme threats to grid operations,potentially leading to significant stability issues or even widespread power blackouts.Simulating power systems’behaviors during cascading failures is of great importance to comprehend how failures originate and propagate,as well as to develop effective preventive and mitigative control strategies.The intricate mechanism of cascading failures,characterized by multi-timescale dynamics,presents exceptional challenges for their simulations.This paper provides a comprehensive review of simulation models for cascading failures,providing a systematic categorization and a comparison of these models.The challenges and potential research directions for the future are also discussed.
基金Under the auspices of Zhejiang Provincial Natural Science Foundation of China(No.LY19C160007)。
文摘In recent years,rapid urbanization has had a profound impact on landscape stability.As a typical example of China's rapid urbanization,Hangzhou has also experienced significant landscape changes,which have profoundly affected its ecological stability.Taking Hangzhou as an example,this study integrates land use change data from 1980 to 2020,combines dynamic simulation and ecological modeling techniques,and carries out a comprehensive analysis of historical trends and future predictions,to provide valuable insights into the complex interactions between urban expansion and landscape stability.The results indicate that:1)between 1980 and2020,Hangzhou experienced a significant increase in construction land at the expense of arable land,leading to a gradual decline in landscape stability,though the downward trend has slowed in recent years.2)The spatial distribution of landscape stability shows clear aggregation patterns,with lower stability concentrated in economically active flatlands and higher stability in the mountainous western regions.3)By 2040,further urban expansion is predicted to occur alongside increased landscape integration,reflecting the positive effects of ecological protection strategies.This study highlights the universal challenges of balancing economic growth with ecological stability in rapidly urbanizing regions.The combination of advanced simulation models and spatiotemporal analysis demonstrates a replicable framework for assessing urban expansion's ecological impacts.These findings underscore the importance of tailoring urban planning and ecological policies to address regional disparities,providing valuable insights for sustainable urban development and landscape management globally.
基金supported by the Science Fund for the Gansu Provincial Natural Science Foundation Project(22JR5RA339).
文摘Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and temporal change characteristics of ecological network and analyzing the integrated relationship between LUCC and ecological security are crucial for ensuring regional ecological security.Gansu is one of the provinces with fragile ecological environment in China,and rapid changes in land use patterns in recent decades have threatened ecological security.Therefore,taking Gansu Province as the study area,this study simulated its land use pattern in 2050 using patch-generating land use simulation(PLUS)model based on the LUCC trend from 2000 to 2020 and integrated the LUCC into morphological spatial pattern analysis(MSPA)to identify ecological sources and extract the ecological corridors to construct ecological network using circuit theory.The results revealed that,according to the prediction results in 2050,the areas of cultivated land,forest land,grassland,water body,construction land,and unused land would be 63,447.52,39,510.80,148,115.18,4605.21,8368.89,and 161,752.40 km^(2),respectively.The number of ecological sources in Gansu Province would increase to 80,with a total area of 99,927.18 km^(2).The number of ecological corridors would increase to 191,with an estimated total length of 6120.66 km.Both ecological sources and ecological corridors showed a sparse distribution in the northwest and dense distribution in the southeast of the province at the spatial scale.The number of ecological pinch points would reach 312 and the total area would expect to increase to 842.84 km^(2),with the most pronounced increase in the Longdong region.Compared with 2020,the number and area of ecological barriers in 2050 would decrease significantly by 63 and 370.71 km^(2),respectively.In general,based on the prediction results,the connectivity of ecological network of Gansu Province would increase in 2050.To achieve the predicted ecological network in 2050,emphasis should be placed on the protection of cultivated land and ecological land,the establishment of ecological sources in desert areas,the reinforcement of the protection for existing ecological sources,and the construction of ecological corridors to enhance the stability of ecological network.This study provides valuable theoretical support and references for the future construction of ecological networks and regional land resource management decision-making.
基金supported by the National Basic Research Program of China (2016YFA0601901)Basic Scientific Research of Henan Academy of Sciences (240601083)Joint Fund of Henan Province Science and Technology Research and Development Program (225200810047)。
文摘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.
文摘AIGaN/GaN HEMTs are investigated by numerical simulation from the self-consistent solution of Schr6dinger-Poisson-hydrodynamic （HD） systems. The influences of polarization charge and quantum effects are considered in this model. Then the two-dimensional conduction band and electron distribution, electron temperature characteristics, Id versus Vd and Id versus Vg, transfer characteristics and transconductance curves are obtained. Corresponding analysis and discussion based on the simulation results are subsequently given.
文摘Validating simulation model is one of the important aspects for modeling and simulation. Some methods of validating model are compared and analyzed. Several typical methods, such as TIC’s inequality coefficient, gray interconnected analysis, direct spectrum estimation, maximum entropy spectral estimation based on Burg or Marple, are chosen and programmed in C language. Some examples by using the program are given. The results show that the program is available and it is best to adopt multi methods for validating models.
文摘The simulation model of the E car HS2000 including the permanent magnetic direct current motor with the augment magnet winding is constructed based on tests in order to simulate the synthetic performance of the electric car. The performance of E car HS2000 is analyzed by means of modeling and programming according to data acquired during tests. The simulation results show that the performance of E car HS2000 is successfully predicted and the model and the corresponding simulation software are feasible for simulating E cars. They can be used as effective tools for analyzing the performance parameters as well as specifications of E cars during prototype stage.
基金Project supported by the National High Technology Research and Development Program of China (863 Program) (No. 2003AA209030) High Technology Research and Development Program of Jiangsu Province (No. BG2004320) the National Natural Science Foundation
文摘A deep understanding of crop-water eco-physiological relations is the basis for quantifying plant physiological responses to soil water stress. Pot experiments were conducted to investigate the winter wheat crop-water relations under both drought and waterlogging conditions in two sequential growing seasons from 2000 to 2002, and then the data were used to develop and validate models simulating the responses of winter wheat growth to drought and waterlogging stress. The experiment consisted of four treatments, waterlogging (keep 1 to 2 cm water layer depth above soil surface), control (70%-80% field capacity), light drought (40%-50% field capacity) and severe drought (30%-40% field capacity) with six replicates at five stages in the 2000-2001 growth season. Three soil water content treatments (waterlogging, control and drought) with two replicates were designed in the 2001-2002 growth season. Waterlogging and control treatments are the same as in the 2000-2001 growth season. For the drought treatment, no water was supplied and the soil moisture decreased from field capacity to wilting point. Leaf net photosynthetic rate, transpiration rate, predawn leaf water potential, soil water potential, soil water content and dry matter weight of individual organs were measured. Based on crop-water eco-physiological relations, drought and waterlogging stress factors for winter wheat growth simulation model were put forward. Drought stress factors integrated soil water availability, the sensitivity of different development stages and the difference between physiological processes (such as photosynthesis, transpiration and partitioning). The quantification of waterlogging stress factor considered different crop species, soil water status, waterlogging days and sensitivity at different growth stages. Data sets from the pot experiments revealed favorable performance reliability for the simulation sub-models with the drought and waterlogging stress factors.
基金Project supported by the Commission of Science, Technology and Industry for National Defence, China (No.Y97# 14-6-2).
文摘Since remote sensing can provide information on the actual status of an agricultural crop, the integration between remote sensing data and crop growth simulation models has become an important trend for yield estimation and prediction.The main objective of this research was to combine a rice growth simulation model with remote sensing data to estimate rice grain yield for different growing seasons leading to an assessment of rice yield at regional levels. Integration between NOAA (National Oceanic and Atmospheric Administration) AVHRR (Advanced Very High Resolution Radiometer) data and the rice growth simulation model ORYZA1 to develop a new software, which was named as Rice-SRS Model, resulted in accurate estimates for rice yield in Shaoxing, China, with an estimation error reduced to 1.03% and 0.79% over-estimation and 0.79% under-estimation for early, single and late season rice, respectively. Selecting suitable dates for remote sensing images was an important factor which could influence estimation accuracy. Thus, given the different growing periods for each rice season, four images were needed for early and late rice, while five images were preferable for single season rice.Estimating rice yield using two or three images was possible, however, if images were obtained during the panicle initiation and heading stages.
文摘The mass configuration of the buoyancy-driven underwater glider is decomposed and defined. The coupling between the glider body and its internal masses is addressed using the energy law. A glider motion model is established, and the corresponding simulation program is derived using MATLAB. The characteristics of the glider motion are explored using this program. The simula- tion results show that the basic characteristic of a buoyancy-driven underwater glider is the periodic alternation of downward and upward motions. The glider's spiral motion can be applied to missions in restricted regions. The glider's horizontal velocity, gliding depth and its motion radius in spiral motion can be changed to meet different application purposes by using different glider parameter designs. The simulation also shows that the model is appropriate and the program has strong simulation functions.
文摘OBJECTIVE To explain the high inter-individual variability and the frequency of exceeding the therapeutic reference range and the laboratory alert level of amisulpride,a popula⁃tion pharmacokinetic model in Chinese patients with schizophrenia was built based on therapeu⁃tic drug monitoring data to guide individualized therapy.METHODS Plasma concentration data(330 measurements from 121 patients)were ana⁃lyzed using a nonlinear mixed-effects model⁃ing approach with first-order conditional estima⁃tion with interaction(FOCE I).The concentra⁃tions of amisulpride were detected by HPLC-MS/MS.Age,weight,sex,combination medication history and renal function status were evaluated as main covariates.The model was internally val⁃idated using goodness-of-fit,bootstrap and nor⁃malized prediction distribution error.Recom⁃mended dosage regimens for patients with key covariates were estimated on the basis of Monte Carlo simulations and the established model.RESULTS A one-compartment model with first-order absorption and elimination was found to adequately characterize amisulpride concentra⁃tion in Chinese patients with schizophrenia.The population estimates of the apparent volume of distribution(V/F)and apparent clearance(CL/F)were 12.7 L and 1.12 L·h-1,respectively.Age sig⁃nificantly affected the clearance of amisulpride and the final model was as follow:CL/F=1.04×(AGE/32)-0.624(L·h-1).To avoid exceeding the lab⁃oratory alert level(640μg·L-1),the model-based simulation results showed that the recommended dose of amisulpride was no more than 600 mg per day for patients aged 60 years,800 mg per day for those aged 40 years and 1200 mg per day for those aged 20 years,respectively.CON⁃CLUSION Dosage optimization of amisulpride can be carried out according to age to reduce the risk of adverse reactions.The model can be used as a suitable tool for designing individual⁃ized therapy for Chinese patients with schizo⁃phrenia.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA17010105)the National Key R&D Program of China(Grant No.2016YFA0602104).
文摘Using the World Meteorological Organization definition and a threshold-based classification technique,simulations of vortex displacement and split sudden stratospheric warmings(SSWs)are evaluated for four Chinese models(BCC-CSM2-MR,FGOALS-f3-L,FGOALS-g3,and NESM3)from phase 6 of the Coupled Model Intercomparison Project(CMIP6)with the Japanese 55-year reanalysis(JRA-55)as a baseline.Compared with six or seven SSWs in a decade in JRA-55,three models underestimate the SSW frequency by~50%,while NESM3 doubles the SSW frequency.SSWs mainly appear in midwinter in JRA-55,but one-month climate drift is simulated in the models.The composite of splits is stronger than displacements in both the reanalysis and most models due to the longer pulse of positive eddy heat flux before onset of split SSWs.A wavenumber-1-like temperature anomaly pattern(cold Eurasia,warm North America)before onset of displacement SSWs is simulated,but cold anomalies are mainly confined to North America after displacement SSWs.Although the lower tropospheric temperature also displays a wavenumber-1-like pattern before split SSWs,most parts of Eurasia and North America are covered by cold anomalies after split SSWs in JRA-55.The models have different degrees of fidelity for the temperature anomaly pattern before split SSWs,but the wavenumber-2-like temperature anomaly pattern is well simulated after split SSWs.The center of the negative height anomalies in the Pacific sector before SSWs is sensitive to the SSW type in both JRA-55 and the models.A negative North Atlantic Oscillation is simulated after both types of SSWs in the models,although it is only observed for split SSWs.
