A Model, called 'Entity-Roles' is proposed in this paper in which the world of Interest is viewed as some mathematical structure. With respect to this structure, a First order (three-valued) Logic Language is ...A Model, called 'Entity-Roles' is proposed in this paper in which the world of Interest is viewed as some mathematical structure. With respect to this structure, a First order (three-valued) Logic Language is constructured.Any world to be modelled can be logically specified in this Language. The integrity constraints on the database and the deducing rules within the Database world are derived from the proper axioms of the world being modelled.展开更多
A scheme for general purposed FDTD visual scientific computing software is introduced in this paper using object-oriented design (OOD) method. By abstracting the parameters of FDTD grids to an individual class and sep...A scheme for general purposed FDTD visual scientific computing software is introduced in this paper using object-oriented design (OOD) method. By abstracting the parameters of FDTD grids to an individual class and separating from the iteration procedure, the visual software can be adapted to more comprehensive computing problems. Real-time gray degree graphic and wave curve of the results can be achieved using DirectX technique. The special difference equation and data structure in dispersive medium are considered, and the peculiarity of parameters in perfectly matched layer are also discussed.展开更多
This paper proposes and illustrates an AI embedded object-oriented methodology to formulate the computable general equilibrium (CGE) models. In this framework, a CGE model is viewed as a collection of objects embedd...This paper proposes and illustrates an AI embedded object-oriented methodology to formulate the computable general equilibrium (CGE) models. In this framework, a CGE model is viewed as a collection of objects embedded AI or namely agents in computer world, corresponding to economic agents and entities in real world, such as government, households, markets and so on. A frame representation of major objects in CGE model is used for trade and environment. Embedded Al object-oriented approach (or software agent) is used in the CGE model representation can able to narrow the gap among the semantic representation, formal CGE (mathematical) representation and computer and algorithm representation, and to improve CGE in understanding and maintenance etc. In such a system, constructing a CGE model to appear an intuitive process rather than an abstract process. This intuitive process needs more understanding of the substance of economics and the logic underlying the problem rather than mathematical notation.展开更多
分别从“点对点”雨量检验和降水空间结构特征检验两方面对多个数值模式东亚夏季中短期逐日降水集合预报进行评估,结果表明不同模式对降水的不同方面存在不一样的预报能力。借助基于对象的诊断评估方法(method for object-based diagnos...分别从“点对点”雨量检验和降水空间结构特征检验两方面对多个数值模式东亚夏季中短期逐日降水集合预报进行评估,结果表明不同模式对降水的不同方面存在不一样的预报能力。借助基于对象的诊断评估方法(method for object-based diagnostic evaluation,简称MODE)提出了基于降水对象的超级集合(Object-based Superensemble,简称OBJSUP)模型,采用观测场和预报场中降水对象空间结构的相似度来分配各个成员模式的权重,有别于利用传统“点对点”误差分析来计算权重的超级集合(Gridpoint-based Superensemble,简称GPSUP)。相比于最优单模式,两种多模式集成预报均有效地提高了中短期降水预报技巧,且OBJSUP模型整体优于GPSUP模型,主要原因在于OBJSUP模型可以较好地改进降水对象的质心位置预报。为进一步检验多模式集成模型对强降水空间结构特征的预报能力,针对2018年夏季广东一次极端强降水事件,多模式集成预报与高分辨率区域模式动力降尺度预报对比表明,多模式集成对强降水的预报不足,但对广东省逐日大雨量级降水和过程累积降水量空间分布预报较好。高分辨率区域模式对此个例中粤东地区发生的强降水具有一定的预报能力,但对广东省其他地区降水量预报偏弱。展开更多
水文模型校准过程对模型模拟效果有重要影响。对学者们应用水文模型SWAT(Soil and Water Assessment Tool)开展的多站点、多变量和多目标的校准策略研究进行了归纳总结分析。研究结果显示:①多站点、多变量和多目标的应用都会对水文模...水文模型校准过程对模型模拟效果有重要影响。对学者们应用水文模型SWAT(Soil and Water Assessment Tool)开展的多站点、多变量和多目标的校准策略研究进行了归纳总结分析。研究结果显示:①多站点、多变量和多目标的应用都会对水文模型的校准结果产生影响。②不是所有的多站点校准都能提高模拟效果,流域尺度、内部情况、站点设置和校准顺序等都会对多站点校准效果产生影响。通常情况下,在大尺度、地形条件复杂、支流众多、非均质的复杂流域进行多站点校准时可有效提高模型的模拟效果,降低模拟的不确定性。③在校准过程中将多站点与多变量校准联合使用,可以更好地模拟流域水文过程,获得更真实合理的水文参数。④不同的目标函数因计算方式的差异也会对校准结果产生影响,使用多个目标函数,可充分利用实测数据所涵盖的信息,更好地进行校准。水文模型校准优化算法与多目标相结合,可缩短校准时间,改善模拟效果。在水文模拟研究中,应充分考虑流域实际情况,进行站点数量与位置、校准变量、目标函数及校准优化算法的选择,以获得更精准的模拟结果。展开更多
文摘A Model, called 'Entity-Roles' is proposed in this paper in which the world of Interest is viewed as some mathematical structure. With respect to this structure, a First order (three-valued) Logic Language is constructured.Any world to be modelled can be logically specified in this Language. The integrity constraints on the database and the deducing rules within the Database world are derived from the proper axioms of the world being modelled.
基金This project was supported by the National Natural Science Foundation (No. 69831020).
文摘A scheme for general purposed FDTD visual scientific computing software is introduced in this paper using object-oriented design (OOD) method. By abstracting the parameters of FDTD grids to an individual class and separating from the iteration procedure, the visual software can be adapted to more comprehensive computing problems. Real-time gray degree graphic and wave curve of the results can be achieved using DirectX technique. The special difference equation and data structure in dispersive medium are considered, and the peculiarity of parameters in perfectly matched layer are also discussed.
文摘This paper proposes and illustrates an AI embedded object-oriented methodology to formulate the computable general equilibrium (CGE) models. In this framework, a CGE model is viewed as a collection of objects embedded AI or namely agents in computer world, corresponding to economic agents and entities in real world, such as government, households, markets and so on. A frame representation of major objects in CGE model is used for trade and environment. Embedded Al object-oriented approach (or software agent) is used in the CGE model representation can able to narrow the gap among the semantic representation, formal CGE (mathematical) representation and computer and algorithm representation, and to improve CGE in understanding and maintenance etc. In such a system, constructing a CGE model to appear an intuitive process rather than an abstract process. This intuitive process needs more understanding of the substance of economics and the logic underlying the problem rather than mathematical notation.
文摘水文模型校准过程对模型模拟效果有重要影响。对学者们应用水文模型SWAT(Soil and Water Assessment Tool)开展的多站点、多变量和多目标的校准策略研究进行了归纳总结分析。研究结果显示:①多站点、多变量和多目标的应用都会对水文模型的校准结果产生影响。②不是所有的多站点校准都能提高模拟效果,流域尺度、内部情况、站点设置和校准顺序等都会对多站点校准效果产生影响。通常情况下,在大尺度、地形条件复杂、支流众多、非均质的复杂流域进行多站点校准时可有效提高模型的模拟效果,降低模拟的不确定性。③在校准过程中将多站点与多变量校准联合使用,可以更好地模拟流域水文过程,获得更真实合理的水文参数。④不同的目标函数因计算方式的差异也会对校准结果产生影响,使用多个目标函数,可充分利用实测数据所涵盖的信息,更好地进行校准。水文模型校准优化算法与多目标相结合,可缩短校准时间,改善模拟效果。在水文模拟研究中,应充分考虑流域实际情况,进行站点数量与位置、校准变量、目标函数及校准优化算法的选择,以获得更精准的模拟结果。