Rough Set is a valid mathematical theory developed in recent years, which has been applied successfully in such fields as machine learning, data mining, intelligent data analyzing and control algorithm acquiring. In t...Rough Set is a valid mathematical theory developed in recent years, which has been applied successfully in such fields as machine learning, data mining, intelligent data analyzing and control algorithm acquiring. In this paper, the authors discuss the reduction of knowledge using conditional entropy in rough set theory. First, the changing tendency of the conditional entropy of decision attributes giving condition attributes is studied from the viewpoint of information. Next, a new reduction algorithm based on conditional entropy is developed. Furthermore, our simulation results show that the algorithm can find the minimal reduction in most cases.展开更多
The basic principles of IF/THEN rules in rough set theory are analyzed first, and then the automatic process of knowledge acquisition is given. The numerical data is qualitatively processed by the classification of me...The basic principles of IF/THEN rules in rough set theory are analyzed first, and then the automatic process of knowledge acquisition is given. The numerical data is qualitatively processed by the classification of membership functions and membership degrees to get the normative decision table. The regular method of relations and the reduction algorithm of attributes are studied. The reduced relations are presented by the multi-representvalue method and its algorithm is offered. The whole knowledge acquisition process has high degree of automation and the extracted knowledge is true and reliable.展开更多
To improve the efficiency of the attribute reduction, we present an attribute reduction algorithm based on background knowledge and information entropy by making use of background knowledge from research fields. Under...To improve the efficiency of the attribute reduction, we present an attribute reduction algorithm based on background knowledge and information entropy by making use of background knowledge from research fields. Under the condition of known background knowledge, the algorithm can not only greatly improve the efficiency of attribute reduction, but also avoid the defection of information entropy partial to attribute with much value. The experimental result verifies that the algorithm is effective. In the end, the algorithm produces better results when applied in the classification of the star spectra data.展开更多
The method and steps of acquiring evaluation rules based on the knowledge reduction theory of rough sets is discussed, and the distilling process and approach for the evaluation rules of mechanical product structure d...The method and steps of acquiring evaluation rules based on the knowledge reduction theory of rough sets is discussed, and the distilling process and approach for the evaluation rules of mechanical product structure design is described by using hydraulic torque converter as an example. Practice shows that this approach to a certain extent simplifies the knowledge base structure and reasoning process in comparison with the case-based reasoning method in the aspect of setting up evaluation rule base and carrying out reasoning to realize the mechanical product evaluation.展开更多
During the procedure of fault diagnosis for large-scale complicated equipment, the existence of redundant and fuzzy information results in the difficulty of knowledge access. Aiming at this characteristic, this paper ...During the procedure of fault diagnosis for large-scale complicated equipment, the existence of redundant and fuzzy information results in the difficulty of knowledge access. Aiming at this characteristic, this paper brought forth the Rough Set （RS） theory to the field of fault diagnosis. By means of the RS theory which is predominant in the way of dealing with fuzzy and uncertain information, knowledge access about fault diagnosis was realized. The foundation ideology of the RS theory was exhausted in detail, an amended RS algorithm was proposed, and the process model of knowledge access based on the amended RS algorithm was researched. Finally, we verified the correctness and the practicability of this method during the procedure of knowledge access.展开更多
Rough set 理论已经在机器学习、从数据库中发现知识、决策支持和分析等方面得到了广泛应用。建立目标威胁模型,首先要挑选特征参数,这里采用知识约简方法选择目标的特征参数;利用神经网络理论建立了威胁模型,目标的威胁程度与特征参数...Rough set 理论已经在机器学习、从数据库中发现知识、决策支持和分析等方面得到了广泛应用。建立目标威胁模型,首先要挑选特征参数,这里采用知识约简方法选择目标的特征参数;利用神经网络理论建立了威胁模型,目标的威胁程度与特征参数的关系可通过神经网络的阀值和权值得到体现,实例表明该方法简单可行。展开更多
文摘Rough Set is a valid mathematical theory developed in recent years, which has been applied successfully in such fields as machine learning, data mining, intelligent data analyzing and control algorithm acquiring. In this paper, the authors discuss the reduction of knowledge using conditional entropy in rough set theory. First, the changing tendency of the conditional entropy of decision attributes giving condition attributes is studied from the viewpoint of information. Next, a new reduction algorithm based on conditional entropy is developed. Furthermore, our simulation results show that the algorithm can find the minimal reduction in most cases.
基金the National Natural Science Foundation of China (50275113).
文摘The basic principles of IF/THEN rules in rough set theory are analyzed first, and then the automatic process of knowledge acquisition is given. The numerical data is qualitatively processed by the classification of membership functions and membership degrees to get the normative decision table. The regular method of relations and the reduction algorithm of attributes are studied. The reduced relations are presented by the multi-representvalue method and its algorithm is offered. The whole knowledge acquisition process has high degree of automation and the extracted knowledge is true and reliable.
基金Supported by the National Natural Science Foundation of China（No. 60573075）, the National High Technology Research and Development Program of China （No. 2003AA133060） and the Natural Science Foundation of Shanxi Province （No. 200601104）.
文摘To improve the efficiency of the attribute reduction, we present an attribute reduction algorithm based on background knowledge and information entropy by making use of background knowledge from research fields. Under the condition of known background knowledge, the algorithm can not only greatly improve the efficiency of attribute reduction, but also avoid the defection of information entropy partial to attribute with much value. The experimental result verifies that the algorithm is effective. In the end, the algorithm produces better results when applied in the classification of the star spectra data.
文摘The method and steps of acquiring evaluation rules based on the knowledge reduction theory of rough sets is discussed, and the distilling process and approach for the evaluation rules of mechanical product structure design is described by using hydraulic torque converter as an example. Practice shows that this approach to a certain extent simplifies the knowledge base structure and reasoning process in comparison with the case-based reasoning method in the aspect of setting up evaluation rule base and carrying out reasoning to realize the mechanical product evaluation.
基金supported by the Shanghai Science and Technology Development Foundation(No.005111070)
文摘During the procedure of fault diagnosis for large-scale complicated equipment, the existence of redundant and fuzzy information results in the difficulty of knowledge access. Aiming at this characteristic, this paper brought forth the Rough Set （RS） theory to the field of fault diagnosis. By means of the RS theory which is predominant in the way of dealing with fuzzy and uncertain information, knowledge access about fault diagnosis was realized. The foundation ideology of the RS theory was exhausted in detail, an amended RS algorithm was proposed, and the process model of knowledge access based on the amended RS algorithm was researched. Finally, we verified the correctness and the practicability of this method during the procedure of knowledge access.
