a model for the Fuel Cell-Battery Hybrid Electric Vehicle (FCHEV) power train in parallel configuration simulation based on the empirical formulation and MATLAB/Simulink blocks has been constructed with the power control strategy using logic threshold approach. Using accelerator pedal signal generated by the driving schedule as the primary input, the simulation implements difference power flow and management under the vehicle operating modes: start, cruise, accelerate and pause. It also incorporates regenerative braking for battery capacity recovery. Main control variables and three group threshold values are evaluated for the vehicle driven under the New Europe Driving Cycle (NEDC) schedule. The results indicate that this configuration of the FCHEV model has capability for battery state of charge (SOC) recovery while meeting vehicle speed and drive power request. The effect that the control thresholds impact on the power distribution and fuel consumption has also been simulated.
{"title":"Modeling and Simulation for Fuel Cell-Battery Hybrid Electric Vehicle","authors":"Qian Ning, D. Xuan, Yang-hai Nan, Youngbae Kim","doi":"10.1109/ICCMS.2009.62","DOIUrl":"https://doi.org/10.1109/ICCMS.2009.62","url":null,"abstract":"a model for the Fuel Cell-Battery Hybrid Electric Vehicle (FCHEV) power train in parallel configuration simulation based on the empirical formulation and MATLAB/Simulink blocks has been constructed with the power control strategy using logic threshold approach. Using accelerator pedal signal generated by the driving schedule as the primary input, the simulation implements difference power flow and management under the vehicle operating modes: start, cruise, accelerate and pause. It also incorporates regenerative braking for battery capacity recovery. Main control variables and three group threshold values are evaluated for the vehicle driven under the New Europe Driving Cycle (NEDC) schedule. The results indicate that this configuration of the FCHEV model has capability for battery state of charge (SOC) recovery while meeting vehicle speed and drive power request. The effect that the control thresholds impact on the power distribution and fuel consumption has also been simulated.","PeriodicalId":325964,"journal":{"name":"2009 International Conference on Computer Modeling and Simulation","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134090695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Faheem Sohail, Farooq Zubairi, Nabeel Sabir, N. Zafar
Layering is a concept widely used in computer and software modeling. Many modern information systems are designed and built using a layered model where the function of each layer is specified and well defined. In this paper we will be discussing the layer whose responsibilities include data extraction, manipulation and provision of data to the rest of the application. Common design problems that designers face while designing object oriented system can be resolved by using design patterns. These patterns are reusable solutions used heavily in application framework design. Formal methods are mathematical techniques used to construct models that can be proved for consistency, completeness and correctness of computerized systems. We have applied formal methods to data access layer patterns which has resulted a verifiable recipes for solving data access layer design problems. Our formal models are described using VDM++ specification language and are analyzed and validated using the VDM++ Toolbox.
{"title":"Designing Verifiable and Reusable Data Access Layer Using Formal Methods and Design Patterns","authors":"Faheem Sohail, Farooq Zubairi, Nabeel Sabir, N. Zafar","doi":"10.1109/ICCMS.2009.83","DOIUrl":"https://doi.org/10.1109/ICCMS.2009.83","url":null,"abstract":"Layering is a concept widely used in computer and software modeling. Many modern information systems are designed and built using a layered model where the function of each layer is specified and well defined. In this paper we will be discussing the layer whose responsibilities include data extraction, manipulation and provision of data to the rest of the application. Common design problems that designers face while designing object oriented system can be resolved by using design patterns. These patterns are reusable solutions used heavily in application framework design. Formal methods are mathematical techniques used to construct models that can be proved for consistency, completeness and correctness of computerized systems. We have applied formal methods to data access layer patterns which has resulted a verifiable recipes for solving data access layer design problems. Our formal models are described using VDM++ specification language and are analyzed and validated using the VDM++ Toolbox.","PeriodicalId":325964,"journal":{"name":"2009 International Conference on Computer Modeling and Simulation","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134500119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In view of the dependence on non-linear parameters of induction motor leading to poor decoupling in conventional vector control, the current control strategy of TSMC fed induction motor using complex vectors is proposed. And mathematic models using complex vectors on TSMC and induction motor are derived and simplified. Then the use of complex vectors root locus figures out complex PI current regulator to solve limitation which serious degradation is apparent as the synchronous frequency increases and to reduce the dependence on motor’s parameters for decoupling control system. Finally, simulation study is carried out for proposed strategy. And results indicate that TSMC have the capacity to supply high quality power and the proposed strategy sharply promotes dynamic and steady state performances of control.
{"title":"Study on Current Control Strategy for Two-Stage Matrix Converter (TSMC) Fed Induction Motor Using Complex Vectors","authors":"Zhiyong Chen, W. Deng","doi":"10.1109/ICCMS.2009.32","DOIUrl":"https://doi.org/10.1109/ICCMS.2009.32","url":null,"abstract":"In view of the dependence on non-linear parameters of induction motor leading to poor decoupling in conventional vector control, the current control strategy of TSMC fed induction motor using complex vectors is proposed. And mathematic models using complex vectors on TSMC and induction motor are derived and simplified. Then the use of complex vectors root locus figures out complex PI current regulator to solve limitation which serious degradation is apparent as the synchronous frequency increases and to reduce the dependence on motor’s parameters for decoupling control system. Finally, simulation study is carried out for proposed strategy. And results indicate that TSMC have the capacity to supply high quality power and the proposed strategy sharply promotes dynamic and steady state performances of control.","PeriodicalId":325964,"journal":{"name":"2009 International Conference on Computer Modeling and Simulation","volume":"52 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133949249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Game between different enterprises in the food chain plays important roles in the food quality. This paper applies the games theory to develop a food supply chain quality management model and describes the implementation algorithm of model. The simulation result shows that the model can simply solve the problem of the optimum quality management in the condition of changing external demand, at this time the largest profit can be obtained, meanwhile, the state of food quality level in whole food supply chain is optimum. Therefore, it is essential for us to take some measures to perfecting reward and punishment mechanism. It can reduce asymmetry information overcome market failures in the food chain, as well as can be traced back and resolve the question from the source once there are some quality problems.
{"title":"Food Supply Chain Quality Management Model and Simulation Based on Game","authors":"Qin Li, W. Song","doi":"10.1109/ICCMS.2009.22","DOIUrl":"https://doi.org/10.1109/ICCMS.2009.22","url":null,"abstract":"Game between different enterprises in the food chain plays important roles in the food quality. This paper applies the games theory to develop a food supply chain quality management model and describes the implementation algorithm of model. The simulation result shows that the model can simply solve the problem of the optimum quality management in the condition of changing external demand, at this time the largest profit can be obtained, meanwhile, the state of food quality level in whole food supply chain is optimum. Therefore, it is essential for us to take some measures to perfecting reward and punishment mechanism. It can reduce asymmetry information overcome market failures in the food chain, as well as can be traced back and resolve the question from the source once there are some quality problems.","PeriodicalId":325964,"journal":{"name":"2009 International Conference on Computer Modeling and Simulation","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133013561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the scene simulation system of UAV, 3D imaging was generated by method -based DEM and massive orthograph that displayed real terrain. The imaging was very realistic. The system adopted the method of cutting down scene based on line of sight, image of cache based on frame and texture swapping, to enhance the speed of PC, and improve performance of the system, so real-time creating scene of massive data on PC was realized. The lifelike imaging was displayed with the environment of VC++, and OpenGL. The technique offers a way for developing UAV scene simulation system, thus of great value in both theory and practice.
{"title":"Study on Technique of 3D Imaging-Based DEM and Massive Orthograph","authors":"G. Jin, Liang-xian Gu, Li-bin Lu","doi":"10.1109/ICCMS.2009.11","DOIUrl":"https://doi.org/10.1109/ICCMS.2009.11","url":null,"abstract":"In the scene simulation system of UAV, 3D imaging was generated by method -based DEM and massive orthograph that displayed real terrain. The imaging was very realistic. The system adopted the method of cutting down scene based on line of sight, image of cache based on frame and texture swapping, to enhance the speed of PC, and improve performance of the system, so real-time creating scene of massive data on PC was realized. The lifelike imaging was displayed with the environment of VC++, and OpenGL. The technique offers a way for developing UAV scene simulation system, thus of great value in both theory and practice.","PeriodicalId":325964,"journal":{"name":"2009 International Conference on Computer Modeling and Simulation","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114486243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Propellant sloshing, which induces perturbations to dynamic behavior of spacecraft, is a conspicuous problem. Thus, sloshing suppression during maneuver poses a challenge on spacecraft control design. Herein, the input shaping technique, which has been validated in reducing residual vibration of flexible structure, is applied on this subject. The input shaper is designed to subject to constraints such as limited amplitude of sloshing disturbance, time optimization and capability of engine. The design procedure is described in this paper. The dynamical influence of propellant sloshing is modeled by a discrete mechanical model. The parameters of the model are calculated by use of Computational Fluid Dynamics (CFD) software and converted to a "sloshing" block to be imported in simulation loop conveniently. In an example, several types of input shapers are designed to suppress the sloshing in spherical vessel. The effectiveness of the shapers is discussed due to the computer simulation results.
{"title":"Spacecraft Propellant Sloshing Suppression Using Input Shaping Technique","authors":"N. Qi, K. Dong, Xianlu Wang, Yunqian Li","doi":"10.1109/ICCMS.2009.20","DOIUrl":"https://doi.org/10.1109/ICCMS.2009.20","url":null,"abstract":"Propellant sloshing, which induces perturbations to dynamic behavior of spacecraft, is a conspicuous problem. Thus, sloshing suppression during maneuver poses a challenge on spacecraft control design. Herein, the input shaping technique, which has been validated in reducing residual vibration of flexible structure, is applied on this subject. The input shaper is designed to subject to constraints such as limited amplitude of sloshing disturbance, time optimization and capability of engine. The design procedure is described in this paper. The dynamical influence of propellant sloshing is modeled by a discrete mechanical model. The parameters of the model are calculated by use of Computational Fluid Dynamics (CFD) software and converted to a \"sloshing\" block to be imported in simulation loop conveniently. In an example, several types of input shapers are designed to suppress the sloshing in spherical vessel. The effectiveness of the shapers is discussed due to the computer simulation results.","PeriodicalId":325964,"journal":{"name":"2009 International Conference on Computer Modeling and Simulation","volume":"240 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116138646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhi-hua Zhang, E. Hou, Zhou Zhao, Nian-dong Deng, Wen Pang
Tunnel is core of mine projects, and 3D tunnel is the important element of 3D geological models for digital mine. According to symmetry of two-dimensional tunnel along the centerline of the tunnel and symmetry of three-dimensional tunnel profiles along centerline, the paper introduced a method of new 3D tunnel modeling: symmetrical modeling, which can be used to realize the modeling of tunnels' intersection. It has resolved the problem that conventional modeling methods existed. But, there are several issues with method, such as data redundancy. Based on introduction of symmetrical modeling, the method is improved by analyzing existed issues. On the platform of Window XP, the MS Visual C++6.0 is selected as the tool of software development and the OpenGL is chosen as the main graphics manipulated tool, the visualization of models is constructed and realized. It is tested that the improved method inherits the merits of the original method and overcomes its' shortcomings, so that the 3D tunnel model is generated with high efficiency.
隧道是矿山工程的核心，三维隧道是数字矿山三维地质模型的重要组成部分。根据二维隧道沿隧道中心线的对称性和三维隧道轮廓沿隧道中心线的对称性，介绍了一种新的三维隧道建模方法:对称建模，该方法可实现隧道交叉点的建模。解决了传统建模方法存在的问题。但是，该方法存在一些问题，例如数据冗余。在引入对称建模的基础上，通过分析存在的问题，对该方法进行了改进。在windows XP平台下，选择MS Visual c++ 6.0作为软件开发工具，OpenGL作为主要图形处理工具，构建并实现了模型的可视化。实验表明，改进后的方法继承了原方法的优点，克服了原方法的不足，能够高效地生成隧道三维模型。
{"title":"An Improved Symmetrical Modeling Method on 3D Tunnel Modeling","authors":"Zhi-hua Zhang, E. Hou, Zhou Zhao, Nian-dong Deng, Wen Pang","doi":"10.1109/ICCMS.2009.35","DOIUrl":"https://doi.org/10.1109/ICCMS.2009.35","url":null,"abstract":"Tunnel is core of mine projects, and 3D tunnel is the important element of 3D geological models for digital mine. According to symmetry of two-dimensional tunnel along the centerline of the tunnel and symmetry of three-dimensional tunnel profiles along centerline, the paper introduced a method of new 3D tunnel modeling: symmetrical modeling, which can be used to realize the modeling of tunnels' intersection. It has resolved the problem that conventional modeling methods existed. But, there are several issues with method, such as data redundancy. Based on introduction of symmetrical modeling, the method is improved by analyzing existed issues. On the platform of Window XP, the MS Visual C++6.0 is selected as the tool of software development and the OpenGL is chosen as the main graphics manipulated tool, the visualization of models is constructed and realized. It is tested that the improved method inherits the merits of the original method and overcomes its' shortcomings, so that the 3D tunnel model is generated with high efficiency.","PeriodicalId":325964,"journal":{"name":"2009 International Conference on Computer Modeling and Simulation","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125088646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the implementation of a rule-based intuitive reasoner is presented. The implementation included the rule induction module and the intuitive reasoner. A large weather database was acquired as the data source. Five weather variables from those data were chosen as the "target variables" whose values were predicted. A "complex" situation was simulated by making only subsets of the data available to the rule induction module. As a result, the rules induced were based on incomplete information with variable levels of certainty. Multiple linear regression was employed to induce rules from the data subsets. The intuitive reasoner was tested for its ability to use the induced rules to predict the values of the target variables. For reference, a weather data analysis approach which had been applied on similar tasks was adopted to analyze the complete database and create predictive models for the same five target variables. The intuitive reasoner showed potential by achieving prediction accuracy which compared favorably with that of the reference approach for two target variables, based on rules induced from only about 10% of the total data.
{"title":"Implementing an Intuitive Reasoner for Predicting Continuous Weather Variables","authors":"Yung-Chien Sun, Grant Clark","doi":"10.1109/ICCMS.2009.70","DOIUrl":"https://doi.org/10.1109/ICCMS.2009.70","url":null,"abstract":"In this paper, the implementation of a rule-based intuitive reasoner is presented. The implementation included the rule induction module and the intuitive reasoner. A large weather database was acquired as the data source. Five weather variables from those data were chosen as the \"target variables\" whose values were predicted. A \"complex\" situation was simulated by making only subsets of the data available to the rule induction module. As a result, the rules induced were based on incomplete information with variable levels of certainty. Multiple linear regression was employed to induce rules from the data subsets. The intuitive reasoner was tested for its ability to use the induced rules to predict the values of the target variables. For reference, a weather data analysis approach which had been applied on similar tasks was adopted to analyze the complete database and create predictive models for the same five target variables. The intuitive reasoner showed potential by achieving prediction accuracy which compared favorably with that of the reference approach for two target variables, based on rules induced from only about 10% of the total data.","PeriodicalId":325964,"journal":{"name":"2009 International Conference on Computer Modeling and Simulation","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116041569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For many applications like video surveillance and digital cinema, it is desirable to encode video content with constant video quality. However, although constant quantization parameter is used in video encoder, quality fluctuation in macroblock level is still very large and standard deviation of PSNR is typically about 1.8dB. Since distortion is introduced in the process of quantization of DCT coefficients, we propose a new DCT-domain distortion model which utilizes the truncated tailing bits in quantization to estimate distortion in macroblock level, and QP of each block is determined by the estimated PSNR. Experimental results show that our proposed model can accurately estimate distortion of each MB before implementing quantization and the corresponding RMSE is only about 0.3dB (less than 1% of the actual value). Compared with previous works, our proposed algorithm can achieve 0.57dB enhancement in quality stabilization.
{"title":"A New DCT-Domain Distortion Model for MB-Level Quality Control","authors":"Xun He, Xianmin Chen, Peilin Liu, S. Goto","doi":"10.1109/ICCMS.2009.28","DOIUrl":"https://doi.org/10.1109/ICCMS.2009.28","url":null,"abstract":"For many applications like video surveillance and digital cinema, it is desirable to encode video content with constant video quality. However, although constant quantization parameter is used in video encoder, quality fluctuation in macroblock level is still very large and standard deviation of PSNR is typically about 1.8dB. Since distortion is introduced in the process of quantization of DCT coefficients, we propose a new DCT-domain distortion model which utilizes the truncated tailing bits in quantization to estimate distortion in macroblock level, and QP of each block is determined by the estimated PSNR. Experimental results show that our proposed model can accurately estimate distortion of each MB before implementing quantization and the corresponding RMSE is only about 0.3dB (less than 1% of the actual value). Compared with previous works, our proposed algorithm can achieve 0.57dB enhancement in quality stabilization.","PeriodicalId":325964,"journal":{"name":"2009 International Conference on Computer Modeling and Simulation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130230221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study the working principle and characteristics of electrical discharge machining was introduced and in order to resolve the kinematic and dynamic research problems. The part simulation method was used by means of ADAMS based on the virtual prototype technique. The data has been changed by using Mechpro. The virtual prototype model was set up. The kinetic and dynamic simulation was conducted analytically and was verified by simulation in ADAMS. The analysis was done for different parts and as a result the velocity, acceleration, force and displacement of gantry and slide carriage were obtained. The results are according with the real conditions which means that the virtual prototype model is reasonable and the simulation is believable. Results achieved from aforementioned analysis can be used in finite element analysis, fatigue life calculation and optimization of these components.
{"title":"Simulation and Analysis of Electrical Discharge Machine Based on Virtual Prototype","authors":"X. Lou, B. Qin, Chun Zheng","doi":"10.1109/ICCMS.2009.30","DOIUrl":"https://doi.org/10.1109/ICCMS.2009.30","url":null,"abstract":"In this study the working principle and characteristics of electrical discharge machining was introduced and in order to resolve the kinematic and dynamic research problems. The part simulation method was used by means of ADAMS based on the virtual prototype technique. The data has been changed by using Mechpro. The virtual prototype model was set up. The kinetic and dynamic simulation was conducted analytically and was verified by simulation in ADAMS. The analysis was done for different parts and as a result the velocity, acceleration, force and displacement of gantry and slide carriage were obtained. The results are according with the real conditions which means that the virtual prototype model is reasonable and the simulation is believable. Results achieved from aforementioned analysis can be used in finite element analysis, fatigue life calculation and optimization of these components.","PeriodicalId":325964,"journal":{"name":"2009 International Conference on Computer Modeling and Simulation","volume":"16 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130433519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：