In this paper, we employ genetic algorithms to solve the migration problem (MP). We propose a new encoding scheme to represent trees, which is composed of two parts: the pre-ordered traversal sequence of tree vertices...In this paper, we employ genetic algorithms to solve the migration problem (MP). We propose a new encoding scheme to represent trees, which is composed of two parts: the pre-ordered traversal sequence of tree vertices and the children number sequence of corresponding tree vertices. The proposed encoding scheme has the advantages of simplicity for encoding and decoding, ease for GA operations, and better equilibrium between exploration and exploitation. It is also adaptive in that, with few restrictions on the length of code, it can be freely lengthened or shortened according to the characteristics of the problem space. Furthermore, the encoding scheme is highly applicable to the degree-constrained minimum spanning tree problem because it also contains the degree information of each node. The simulation results demonstrate the higher performance of our algorithm, with fast convergence to the optima or sub-optima on various problem sizes. Comparing with the binary string encoding of vertices, when the problem size is large, our algorithm runs remarkably faster with comparable search capability. Key words distributed information retrieval - mobile agents - migration problem - genetic algorithms CLC number TP 301. 6 Foundation item: Supported by the National Natural Science Foundation of China (90104005), the Natural Science Foundation of Hubei Province and the Hong Kong Polytechnic University under the grant G-YD63Biography: He Yan-xiang (1952-), male, Professor, research direction: distributed and parallel processing, multi-agent systems, data mining and e-business.展开更多
Mesoporous molecular sieves possessing high mesopore volumes and large specific surface areas were prepared and characterized by means of XRD, low temperature N_2 adsorption-desorption measurements, FT IR, Raman, UV...Mesoporous molecular sieves possessing high mesopore volumes and large specific surface areas were prepared and characterized by means of XRD, low temperature N_2 adsorption-desorption measurements, FT IR, Raman, UV-visible diffuse reflectance and XPS spectroscopy. The materials contain both framework and extra-framework Ti centers which exhibit selective oxidation catalytic activity and photocatalytic activity respectively. The catalysis of selective oxidation was studied with the hydroxylation of benzene with hydrogen peroxide and photochemical activity was studied by the yields of ·OH and H_2O_2, respectively.展开更多
We combine the web usage mining and fuzzy clustering and give the concept of web fuzzy clustering, and then put forward the web fuzzy clustering processing model which is discussed in detail. Web fuzzy clustering can ...We combine the web usage mining and fuzzy clustering and give the concept of web fuzzy clustering, and then put forward the web fuzzy clustering processing model which is discussed in detail. Web fuzzy clustering can be used in the web users clustering and web pages clustering. In the end, a case study is given and the result has proved the feasibility of using web fuzzy clustering in web pages clustering. Key words web mining - web usage mining - web fuzzy clustering - WFCM CLC number TP 391 Foundation item: Supported by the National Natural Science Foundation of China (90104005)Biography: LIU Mao-fu (1977-), male, Ph. D candidate, research direction: artificial intelligence, web mining, image mining.展开更多
文摘In this paper, we employ genetic algorithms to solve the migration problem (MP). We propose a new encoding scheme to represent trees, which is composed of two parts: the pre-ordered traversal sequence of tree vertices and the children number sequence of corresponding tree vertices. The proposed encoding scheme has the advantages of simplicity for encoding and decoding, ease for GA operations, and better equilibrium between exploration and exploitation. It is also adaptive in that, with few restrictions on the length of code, it can be freely lengthened or shortened according to the characteristics of the problem space. Furthermore, the encoding scheme is highly applicable to the degree-constrained minimum spanning tree problem because it also contains the degree information of each node. The simulation results demonstrate the higher performance of our algorithm, with fast convergence to the optima or sub-optima on various problem sizes. Comparing with the binary string encoding of vertices, when the problem size is large, our algorithm runs remarkably faster with comparable search capability. Key words distributed information retrieval - mobile agents - migration problem - genetic algorithms CLC number TP 301. 6 Foundation item: Supported by the National Natural Science Foundation of China (90104005), the Natural Science Foundation of Hubei Province and the Hong Kong Polytechnic University under the grant G-YD63Biography: He Yan-xiang (1952-), male, Professor, research direction: distributed and parallel processing, multi-agent systems, data mining and e-business.
基金Supported by the State Major Basic Research Project of China(No. 2 0 0 0 0 4 80 0 9) and the National Natural ScienceFoundation of China(No. 2 0 1730 0 3)
文摘Mesoporous molecular sieves possessing high mesopore volumes and large specific surface areas were prepared and characterized by means of XRD, low temperature N_2 adsorption-desorption measurements, FT IR, Raman, UV-visible diffuse reflectance and XPS spectroscopy. The materials contain both framework and extra-framework Ti centers which exhibit selective oxidation catalytic activity and photocatalytic activity respectively. The catalysis of selective oxidation was studied with the hydroxylation of benzene with hydrogen peroxide and photochemical activity was studied by the yields of ·OH and H_2O_2, respectively.
文摘We combine the web usage mining and fuzzy clustering and give the concept of web fuzzy clustering, and then put forward the web fuzzy clustering processing model which is discussed in detail. Web fuzzy clustering can be used in the web users clustering and web pages clustering. In the end, a case study is given and the result has proved the feasibility of using web fuzzy clustering in web pages clustering. Key words web mining - web usage mining - web fuzzy clustering - WFCM CLC number TP 391 Foundation item: Supported by the National Natural Science Foundation of China (90104005)Biography: LIU Mao-fu (1977-), male, Ph. D candidate, research direction: artificial intelligence, web mining, image mining.
