随着网络信息资源的迅速增加,如何及时准确地获取所需信息是现代网络信息过滤技术需要解决的主要问题。为了给用户提供更准确的信息,提出了一种基于用户反馈的智能合作过滤模型(Agent collaborative filtering model based on users' feedback,ACFM)和用户兴趣模型,该模型通过隐式反馈和显式反馈这两种用户兴趣反馈学习实现合作过滤。实验结果表明,ACFM在预测用户兴趣的效果和推荐搜索信息的准确率方面比传统的搜索引擎有明显改善。
Foley-Sammon linear discriminant analysis (FSLDA) and uncorrelated linear discriminant analysis (ULDA) are two well-known kinds of linear discriminant analysis. Both ULDA and FSLDA search the kth discriminant vector in an n-k+1 dimensional subspace, while they are subject to their respective constraints. Evidenced by strict demonstration, it is clear that in essence ULDA vectors are the covariance-orthogonal vectors of the corresponding eigen-equation. So, the algorithms for the covariance-orthogonal vectors are equivalent to the original algorithm of ULDA, which is time-consuming. Also, it is first revealed that the Fisher criterion value of each FSLDA vector must be not less than that of the corresponding ULDA vector by theory analysis. For a discriminant vector, the larger its Fisher criterion value is, the more powerful in discriminability it is. So, for FSLDA vectors, corresponding to larger Fisher criterion values is an advantage. On the other hand, in general any two feature components extracted by FSLDA vectors are statistically correlated with each other, which may make the discriminant vectors set at a disadvantageous position. In contrast to FSLDA vectors, any two feature components extracted by ULDA vectors are statistically uncorrelated with each other. Two experiments on CENPARMI handwritten numeral database and ORL database are performed. The experimental results are consistent with the theory analysis on Fisher criterion values of ULDA vectors and FSLDA vectors. The experiments also show that the equivalent algorithm of ULDA, presented in this paper, is much more efficient than the original algorithm of ULDA, as the theory analysis expects. Moreover, it appears that if there is high statistical correlation between feature components extracted by FSLDA vectors, FSLDA will not perform well, in spite of larger Fisher criterion value owned by every FSLDA vector. However, when the average correlation coefficient of feature components extracted by FSLDA vectors is at a low level, the performance of FSLD
为提高基于Agent的信息检索系统在海量的网络信息检索中查询准确率,提出了基于多兴趣Agent层次结构的检索系统模型(IRHOMIA,information retrieval system based on hierarchically organizedofmulti-interest Agent),模型对查询信息进行了兴趣预测并生成了用户兴趣项权重向量,输入到训练过的神经网络并把输出层生成向量中的每个值与给定的阈值进行比较来确定将查询任务分配给其他兴趣Agent或者是拥有相应资源的查询工具。试验表明,IRHOMIA在预测用户兴趣的效果和推荐搜索信息的准确率方面比传统的检索系统以及单兴趣Agent检索系统IRHOIA有5%以上的提高。
