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为探究性学习打开一个窗口——从学生的《问题集》说起
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作者 顾亚平 《生物学教学》 北大核心 2005年第5期32-34,共3页
关键词 中学 生物教学 探究性学习 《问题集》 科学素养
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Applying memetic algorithm-based clustering to recommender system with high sparsity problem 被引量:2
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作者 MARUNG Ukrit THEERA-UMPON Nipon AUEPHANWIRIYAKUL Sansanee 《Journal of Central South University》 SCIE EI CAS 2014年第9期3541-3550,共10页
A new recommendation method was presented based on memetic algorithm-based clustering. The proposed method was tested on four highly sparse real-world datasets. Its recommendation performance is evaluated and compared... A new recommendation method was presented based on memetic algorithm-based clustering. The proposed method was tested on four highly sparse real-world datasets. Its recommendation performance is evaluated and compared with that of the frequency-based, user-based, item-based, k-means clustering-based, and genetic algorithm-based methods in terms of precision, recall, and F1 score. The results show that the proposed method yields better performance under the new user cold-start problem when each of new active users selects only one or two items into the basket. The average F1 scores on all four datasets are improved by 225.0%, 61.6%, 54.6%, 49.3%, 28.8%, and 6.3% over the frequency-based, user-based, item-based, k-means clustering-based, and two genetic algorithm-based methods, respectively. 展开更多
关键词 memetic algorithm recommender system sparsity problem cold-start problem clustering method
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A new clustering algorithm for large datasets 被引量:1
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作者 李清峰 彭文峰 《Journal of Central South University》 SCIE EI CAS 2011年第3期823-829,共7页
The Circle algorithm was proposed for large datasets.The idea of the algorithm is to find a set of vertices that are close to each other and far from other vertices.This algorithm makes use of the connection between c... The Circle algorithm was proposed for large datasets.The idea of the algorithm is to find a set of vertices that are close to each other and far from other vertices.This algorithm makes use of the connection between clustering aggregation and the problem of correlation clustering.The best deterministic approximation algorithm was provided for the variation of the correlation of clustering problem,and showed how sampling can be used to scale the algorithms for large datasets.An extensive empirical evaluation was given for the usefulness of the problem and the solutions.The results show that this method achieves more than 50% reduction in the running time without sacrificing the quality of the clustering. 展开更多
关键词 data mining Circle algorithm clustering categorical data clustering aggregation
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Try and error-based scheduling algorithm for cluster tools of wafer fabrications with residency time constraints 被引量:4
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作者 ZHOU Bing-hai LI Xin 《Journal of Central South University》 SCIE EI CAS 2012年第1期187-192,共6页
To improve the productivity of cluster tools in semiconductor fabrications,on the basis of stating scheduling problems,a try and error-based scheduling algorithm was proposed with residency time constraints and an obj... To improve the productivity of cluster tools in semiconductor fabrications,on the basis of stating scheduling problems,a try and error-based scheduling algorithm was proposed with residency time constraints and an objective of minimizing Makespan for the wafer jobs in cluster tools.Firstly,mathematical formulations of scheduling problems were presented by using assumptions and definitions of a scheduling domain.Resource conflicts were analyzed in the built scheduling model,and policies to solve resource conflicts were built.A scheduling algorithm was developed.Finally,the performances of the proposed algorithm were evaluated and compared with those of other methods by simulations.Experiment results indicate that the proposed algorithm is effective and practical in solving the scheduling problem of the cluster tools. 展开更多
关键词 cluster tools residency constraints scheduling model ALGORITHM simulation experiments
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Similarity measure design on overlapped and non-overlapped data
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作者 LEE Sang-hyuk SHIN Seung-soo 《Journal of Central South University》 SCIE EI CAS 2013年第9期2440-2446,共7页
Similarity measure design on non-overlapped data was carried out and compared with the case of overlapped data.Unconsistant feature of similarity on overlapped data to non-overlapped data was provided by example.By th... Similarity measure design on non-overlapped data was carried out and compared with the case of overlapped data.Unconsistant feature of similarity on overlapped data to non-overlapped data was provided by example.By the artificial data illustration,it was proved that the conventional similarity measure was not proper to calculate the similarity measure of the non-overlapped case.To overcome the unbalance problem,similarity measure on non-overlapped data was obtained by considering neighbor information.Hence,different approaches to design similarity measure were proposed and proved by consideration of neighbor information.With the example of artificial data,similarity measure calculation was carried out.Similarity measure extension to intuitionistic fuzzy sets(IFSs)containing uncertainty named hesitance was also followed. 展开更多
关键词 similarity measure overlapped data non-overlapped data intuitionistic data
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