共查询到20条相似文献，搜索用时 31 毫秒
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Collaborative filtering (CF) is a popular method for personalizing product recommendations for e-commerce applications. In order to recommend a product to a user and predict that user’s preference, CF utilizes product evaluation ratings of like-minded users. The process of finding like-minded users forms a social network among all users and each link between two users represents an implicit connection between them. Users having more connections with others are the most influential users. Attacking recommender systems is a new issue for these systems. Here, an attacker tries to manipulate a recommender system in order to change the recommendation output according to her wish. If an attacker succeeds, her profile is used over and over again by the recommender system, making her an influential user. In this study, we applied the established attack detection methods to the influential users, instead of the whole user set, to improve their attack detection performance. Experiments were conducted using the same settings previously used to test the established methods. The results showed that the proposed influence-based method had better detection performance and improved the stability of a recommender system for most attack scenarios. It performed considerably better than established detection methods for attacks that inserted low numbers of attack profiles (20–25 %). 相似文献
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Scale and Translation Invariant Collaborative Filtering Systems 总被引：1，自引：0，他引：1
Daniel Lemire 《Information Retrieval》2005,8(1):129-150
Collaborative filtering systems are prediction algorithms over sparse data sets of user preferences. We modify a wide range of state-of-the-art collaborative filtering systems to make them scale and translation invariant and generally improve their accuracy without increasing their computational cost. Using the EachMovie and the Jester data sets, we show that learning-free constant time scale and translation invariant schemes outperforms other learning-free constant time schemes by at least 3% and perform as well as expensive memory-based schemes (within 4%). Over the Jester data set, we show that a scale and translation invariant Eigentaste algorithm outperforms Eigentaste 2.0 by 20%. These results suggest that scale and translation invariance is a desirable property. 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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Dennis Bachmann Katarina Grolinger Hany ElYamany Wilson Higashino Miriam Capretz Majid Fekri Bala Gopalakrishnan 《Information Retrieval》2018,21(6):541-564
Recommender systems have dramatically changed the way we consume content. Internet applications rely on these systems to help users navigate among the ever-increasing number of choices available. However, most current systems ignore the fact that user preferences can change according to context, resulting in recommendations that do not fit user interests. This research addresses these issues by proposing the \(({ CF})^2\) architecture, which uses local learning techniques to embed contextual awareness into collaborative filtering models. The proposed architecture is demonstrated on two large-scale case studies involving over 130 million and over 7 million unique samples, respectively. Results show that contextual models trained with a small fraction of the data provided similar accuracy to collaborative filtering models trained with the complete dataset. Moreover, the impact of taking into account context in real-world datasets has been demonstrated by higher accuracy of context-based models in comparison to random selection models. 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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信息过滤研究 总被引：13，自引：1，他引：12
刘柏嵩 《现代图书情报技术》2003,(6):23-26
提出了一种新的数字图书馆信息过滤方法，它具有三个显著的优点：一是采用了混合信息过滤模型，克服了基于内容和协作过滤的不足；二是建立用户模板，解决了用户兴趣的获取问题；三是信息内容采用本体来组织，实现语义级查询和高效的匹配机制。 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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拟合用户兴趣演变特性的协作过滤推荐算法 总被引：2，自引：0，他引：2
个性化推荐技术是将传统的数据挖掘技术同用户访问信息结合起来,根据用户的兴趣爱好来对用户可能访问的内容进行预测并预取其提供给用户进行选择.目前协作过滤技术是个性化推荐系统中应用最为成功的推荐技术之一,但传统的协作过滤算法没有考虑用户的兴趣演变,难以有效地反映用户真实兴趣.在分析目前协作过滤算法存在问题的基础上,利用用户访问兴趣分为偶然兴趣和稳定兴趣的特性,文章提出了基于偶然兴趣的推荐权重和基于稳定兴趣的推荐权重,并将它们融入新的拟合用户兴趣演变的协作过滤算法中.实验表明该算法能准确地反映用户访问兴趣,较传统的协作过滤算法可以有效提高推荐精度. 相似文献
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Borrowing From e-commerce; Are Recommender Systems Good for Libraries? For past 10 years recommender systems have attempted to match customers to materials in the e-commerce world. Utilizing specifically designed recommender systems to meet the needs of patrons, collaborative filtering, and content-based recommender systems are the two basic types with several hybrids created from these two have been significantly enhancing digital library services. Security issues come into play in a special way with libraries, and plagiarism can also affect recommender quality. Open Source tools may be the answer for libraries and their customers, enabling a better utilization of all that a library has to offer. 相似文献
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文献推荐系统：提高信息检索效率之途 总被引：2，自引：0，他引：2
Traditional Information Retrieval (IR) systems have limitations in improving search performance in today’s information environment. The high recall and poor precision of traditional IR systems are only as good as with the accuracy of search query, which is, however, usually difficult for the user to construct. It is also time-consuming for the user to evaluate each search result. The recommendation techniques having been developed since the early 1990s help solve the problems that traditional IR systems have. This paper explains the basic process and major elements of document recommender systems, especially the two recommendation techniques of content-based filtering and collaborative filtering. Also discussed are the evaluation issue and the problems that current document recommender systems are facing, which need to be taken into account in future system designs. Traditional Information Retrieval (IR) systems have limitations in improving search performance in today’s information environment. The high recall and poor precision of traditional IR systems are only as good as with the accuracy of search query, which is, however, usually difficult for the user to construct. It is also time-consuming for the user to evaluate each search result. The recommendation techniques having been developed since the early 1990s help solve the problems that traditional IR systems have. This paper explains the basic process and major elements of document recommender systems, especially the two recommendation techniques of content-based filtering and collaborative filtering. Also discussed are the evaluation issue and the problems that current document recommender systems are facing, which need to be taken into account in future system designs. 相似文献
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In the IR field it is clear that the value of a system depends on the cost and benefit profiles of its users. It would seem obvious that different users would prefer different systems. In the TREC-9 filtering track, systems are evaluated by a utility measure specifying a given cost and benefit. However, in the study of decision systems it is known that, in some cases, one system may be unconditionally better than another. In this paper we employ a decision theoretic approach to find conditions under which an Information Filtering (IF) system is unconditionally superior to another for all users regardless of their cost and benefit profiles.It is well known that if two IF systems have equal precision the system with better recall will be preferred by all users. Similarly, with equal recall, better precision is universally preferred. We confirm these known results and discover an unexpected dominance relation in which a system with lower recall will be universally preferred provided its precision is sufficiently higher. 相似文献
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《Journal of Informetrics》2020,14(4):101075
Greater collaboration generally produces higher category normalised citation impact (CNCI) and more influential science. Citation differences between domestic and international collaborative articles are known, but obscured in analyses of countries’ CNCIs, compromising evaluation insights. Here, we address this problem by deconstructing and distinguishing domestic and international collaboration types to explore differences in article citation rates between collaboration type and countries. Using Web of Science article data covering 2009–2018, we find that individual country citation and CNCI profiles vary significantly between collaboration types (e.g., domestic single institution and international bilateral) and credit counting methods (full and fractional). The ‘boosting’ effect of international collaboration is greatest where total research capacity is smallest, which could mislead interpretation of performance for policy and management purposes. By incorporating collaboration type into the CNCI calculation, we define a new metric labelled Collab-CNCI. This can account for collaboration effects without presuming credit (as fractional counting does). We recommend that analysts should: (1) partition all article datasets so that citation counts can be normalised by collaboration type (Collab-CNCI) to enable improved interpretation for research policy and management; and (2) consider filtering out smaller entities from multinational and multi-institutional analyses where their inclusion is likely to obscure interpretation. 相似文献
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协同过滤推荐研究综述 总被引：6，自引：1，他引：6
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国外信息过滤系统的研究综述 总被引：9，自引：0，他引：9
明确了信息过滤系统与相关系统的区别，设计了一个框架，根据多种标准对信息过滤系统进行分类；阐述了相关的过滤方法；描述了信息过滤系统的重要概念和用于实现的技术；讨论信息过滤系统的评估方法及其局限性。最后，文章对信息过滤系统发展方向进行了展望。 相似文献
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《The Journal of Academic Librarianship》2020,46(5):102195
Built on a pilot study, this study examined how librarians understand fake news and the specific methods or strategies they suggest for detecting fake news by analyzing their guides from academic libraries. A content analysis regarding a total of 21 institutional guides was conducted. The major findings include the following: 1) in the librarians' guides stating their definition of fake news, the two elements of falsity and the intention to mislead were explicitly stated. The other element of bias, however, was presented in only some guides. 2) The sub-elements of clickbait, a decontextualized content and omitted information were inconsistently or barely presented across these guides. 3) Only two institutional libraries put forth the notion of fact in relation to fake news in their guides. 4) All of the guides suggested checklist approaches to detecting fake news or evaluating news sources. Finally, 5) librarians acknowledge the influence of human biases on consuming news. However, psychological factors are minimally presented in most of the guides. This study provides a few suggestions. First, librarians must further clarify the term fake news so that it reflects its multiple layers. Second, librarians must incorporate new strategies, such as lateral reading and click restraints, in combination with a few prioritized elements of a checklist into their guides regarding detecting fake news. Finally, librarians must pay attention to psychological factors more when interpreting facts in their strategies about news sources and fake news. 相似文献
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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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目前协同过滤被广泛应用于数字图书馆、电子商务等领域的个性化服务系统.最近邻算法则是最早提出和最主要的协同过滤推荐算法,但用户评分数据稀疏性严重影响推荐质量.针对上述问题,提出了一种基于Rough集理论的最近邻协同过滤算法,以用户评分项并集作为用户相似性计算基础,并将非目标用户区分为无推荐能力和有推荐能力两种类型;对于无推荐能力用户不再计算用户相似性以改善推荐实时性,对于有推荐能力用户则提出一种基于Rough集理论的评分预测方法来填补用户评分项并集中的缺失值,从而降低数据稀疏性.实验结果表明新算法能有效提高推荐质量. 相似文献