共查询到18条相似文献，搜索用时 328 毫秒
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基于Hadoop开源分布式计算框架和Mahout协同过滤推荐引擎技术构建图书推荐引擎系统,并利用云模型和Pearson系数对传统协同过滤推荐算法进行改进,改善传统单机推荐算法在高维稀疏矩阵上进行运算所导致的系统性能不佳及推荐结果不准确的问题。利用实验对分布式推荐平台的整体性能及改善后的协同过滤推荐算法进行测试评估,发现当虚拟机节点不断增加时,协同过滤推荐引擎的计算时间不断减少,这表明推荐引擎系统的总体性能较传统单机推荐引擎得到提升;利用MAE分别对原始协同过滤推荐效果和改进后的推荐算法进行测评,发现改进后的推荐引擎算法的推荐准确率较改进前提高13.1%。 相似文献
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[目的/意义] 为解决高校图书推荐过程中面临的“数据稀疏”和“冷启动”问题,研究表明：优化读者评价矩阵和相似度模型是提高图书推荐质量的关键。[方法/过程] 提出一种协同过滤改进方法,以图书分类为项目生成用户评价矩阵,并考虑借阅方式、借阅时间和图书相似度对用户兴趣度的影响,优化矩阵中的样本数据;同时,在计算读者相似度时融入读者特征和图书特征。[结果/结论] 实验结果表明,该方法可有效解决“数据稀疏”和“冷启动”问题,显著降低计算量。与基本协同过滤和聚类改进的协同过滤方法相比,无论是在推荐准确率还是在用户满意率上都有较大的提高,综合推荐效果更好。 相似文献
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基于协同过滤的数字图书馆推荐系统研究 总被引：10，自引：0，他引：10
信息推荐服务是数字图书馆的一项重要功能。该文论述了基于协同过滤的数字图书馆推荐系统的基本原理与特点、数字图书馆进行协同推荐的必要性,介绍了基于协同过滤推荐系统的主要方法和技术,并分析了目前协同过滤方法在数字图书馆推荐系统中应用的一些实例。 相似文献
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利用云模型改进基于项目的协同过滤推荐算法 总被引：1，自引：1，他引：1
基于项目的协同过滤推荐算法能有效解决传统的基于用户的协同过滤推荐系统可扩展性差、缺乏稳定性的缺点,但仍然不能解决数据稀疏的问题,在数据极度稀疏的情况下,传统的项目相似性度量方法无法实现准确度量,导致推荐效果急剧下滑。本文借鉴基于云模型的云相似性度量方法来实现基于知识层面的项目相似性度量,提出了一种新的基于项目的协同过滤推荐算法。实验结果表明即使在数据极度稀疏的情况下,改进后的算法仍然能取得较好的推荐效果。 相似文献
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[目的/意义]将认知升级理论融入图书馆智慧推荐服务中,以实现知以藏往、见贤思齐的智慧化推荐服务。[方法/过程]首先,从兴趣热度、内容质量评价和专指度3个指标入手,构建图书馆智慧推荐系统的指标体系;其次,基于认知升级理论,将用户分为“前辈”和“后辈”,通过改进协同过滤推荐算法计算用户相似度,将“前辈”的成功学习路径推荐给相似的后辈;最后,利用精准率、召回率、AUC、MMR、F1值等指标对离线实验和在线实验结果进行检验。[结果/结论]实验结果表明,改进后的智慧推荐算法相比传统协同过滤算法的实现效果有明显提高;对比离线实验和在线实验结果发现,在线实验的推荐效果显著提升,意味着若将基于认知升级理论的智慧推荐服务加以推广,将会对高校学生的专业素质培养和认知层次升级产生积极影响。 相似文献
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基于知识的协同过滤推荐系统研究 总被引：2，自引：2，他引：0
传统的基于项目的协同过滤算法,不能很好地解决数据稀疏和新项目问题(冷启动)带来的推荐质量下降的问题.笔者从智能检索的思想出发,提出一种新的基于知识的协同过滤推荐算法.该算法借助于领域本体,表达语义知识,增加了项目之间的关联信息;考虑到领域本体中结点、边、深度和密度对相似性计算的不同影响,算法结合信息论中的互信息相关概念,对相似性计算公式进行改进,提高了运算精度.实验结果表明,该算法相对于传统的基于项目的协同过滤推荐算法而言,可有效缓解由数据集稀疏和冷启动带来的问题,显著提高推荐系统的推荐质量. 相似文献
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When speaking of information retrieval, we often mean text retrieval. But there exist many other forms of information retrieval applications. A typical example is collaborative filtering that suggests interesting items to a user by taking into account other users’ preferences or tastes. Due to the uniqueness of the problem, it has been modeled and studied differently in the past, mainly drawing from the preference prediction and machine learning view point. A few attempts have yet been made to bring back collaborative filtering to information (text) retrieval modeling and subsequently new interesting collaborative filtering techniques have been thus derived. In this paper, we show that from the algorithmic view point, there is an even closer relationship between collaborative filtering and text retrieval. Specifically, major collaborative filtering algorithms, such as the memory-based, essentially calculate the dot product between the user vector (as the query vector in text retrieval) and the item rating vector (as the document vector in text retrieval). Thus, if we properly structure user preference data and employ the target user’s ratings as query input, major text retrieval algorithms and systems can be directly used without any modification. In this regard, we propose a unified formulation under a common notational framework for memory-based collaborative filtering, and a technique to use any text retrieval weighting function with collaborative filtering preference data. Besides confirming the rationale of the framework, our preliminary experimental results have also demonstrated the effectiveness of the approach in using text retrieval models and systems to perform item ranking tasks in collaborative filtering. 相似文献
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基于内容和协作的信息过滤方法研究 总被引：7，自引：0，他引：7
随着互联网上信息的迅速增长,信息过滤技术得到越来越广泛的应用。本文论述了内容过滤和协作过滤两种信息过滤技术,针对它们存在的问题,提出一种结合两种过滤技术的方法。实验结果表明,该方法能较好地解决问题,提高过滤结果的准确性,是一种更好的信息过滤方法 相似文献
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Privacy-preserving collaborative filtering algorithms are successful approaches. However, they are susceptible to shilling attacks. Recent research has increasingly focused on collaborative filtering to protect against both privacy and shilling attacks. Malicious users may add fake profiles to manipulate the output of privacy-preserving collaborative filtering systems, which reduces the accuracy of these systems. Thus, it is imperative to detect fake profiles for overall success. Many methods have been developed for detecting attack profiles to keep them outside of the system. However, these techniques have all been established for non-private collaborative filtering schemes. The detection of shilling attacks in privacy-preserving recommendation systems has not been deeply examined. In this study, we examine the detection of shilling attacks in privacy-preserving collaborative filtering systems. We utilize four attack-detection methods to filter out fake profiles produced by six well-known shilling attacks on perturbed data. We evaluate these detection methods with respect to their ability to identify bogus profiles. Real data-based experiments are performed. Empirical outcomes demonstrate that some of the detection methods are very successful at filtering out fake profiles in privacy-preserving collaborating filtering schemes. 相似文献
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Collaborative filtering is a general technique for exploiting the preference patterns of a group of users to predict the utility
of items for a particular user. Three different components need to be modeled in a collaborative filtering problem: users,
items, and ratings. Previous research on applying probabilistic models to collaborative filtering has shown promising results.
However, there is a lack of systematic studies of different ways to model each of the three components and their interactions.
In this paper, we conduct a broad and systematic study on different mixture models for collaborative filtering. We discuss
general issues related to using a mixture model for collaborative filtering, and propose three properties that a graphical
model is expected to satisfy. Using these properties, we thoroughly examine five different mixture models, including Bayesian
Clustering (BC), Aspect Model (AM), Flexible Mixture Model (FMM), Joint Mixture Model (JMM), and the Decoupled Model (DM).
We compare these models both analytically and experimentally. Experiments over two datasets of movie ratings under different
configurations show that in general, whether a model satisfies the proposed properties tends to be correlated with its performance.
In particular, the Decoupled Model, which satisfies all the three desired properties, outperforms the other mixture models
as well as many other existing approaches for collaborative filtering. Our study shows that graphical models are powerful
tools for modeling collaborative filtering, but careful design is necessary to achieve good performance. 相似文献
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一个新的基于协作过滤的用户浏览预测模型 总被引：2，自引：0，他引：2
本文提出了一个新的基于协作过滤的用户浏览协作预测模型———UNCPM ,它有效地解决了目前协作过滤预测方法的准确性和覆盖率低等问题。UNCPM从Web日志中获取用户浏览信息 ,系统分为两个部分 :离线构件和在线构件。离线构件用于用户浏览历史记录的K means聚类 ,并在聚类时充分考虑URL的相似分析来避免协作过滤的同义性和分散性等不足 ;在线构件用于活动用户预测。该模型可以应用在大型电子商务网站的用户浏览预测上。 相似文献
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An Empirical Analysis of Design Choices in Neighborhood-Based Collaborative Filtering Algorithms 总被引：4，自引：0，他引：4
Collaborative filtering systems predict a user's interest in new items based on the recommendations of other people with similar interests. Instead of performing content indexing or content analysis, collaborative filtering systems rely entirely on interest ratings from members of a participating community. Since predictions are based on human ratings, collaborative filtering systems have the potential to provide filtering based on complex attributes, such as quality, taste, or aesthetics. Many implementations of collaborative filtering apply some variation of the neighborhood-based prediction algorithm. Many variations of similarity metrics, weighting approaches, combination measures, and rating normalization have appeared in each implementation. For these parameters and others, there is no consensus as to which choice of technique is most appropriate for what situations, nor how significant an effect on accuracy each parameter has. Consequently, every person implementing a collaborative filtering system must make hard design choices with little guidance. This article provides a set of recommendations to guide design of neighborhood-based prediction systems, based on the results of an empirical study. We apply an analysis framework that divides the neighborhood-based prediction approach into three components and then examines variants of the key parameters in each component. The three components identified are similarity computation, neighbor selection, and rating combination. 相似文献
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基于协作过滤的Web智能信息推荐方法 总被引：1，自引：0，他引：1