Explanation in Recommender Systems

There is increasing awareness in recommender systems research of the need to make the recommendation process more transparent to users. Following a brief review of existing approaches to explanation in recommender systems, we focus in this paper on a case-based reasoning (CBR) approach to product recommendation that offers important benefits in terms of the ease with which the recommendation process can be explained and the system’s recommendations can be justified. For example, recommendations based on incomplete queries can be justified on the grounds that the user’s preferences with respect to attributes not mentioned in her query cannot affect the outcome. We also show how the relevance of any question the user is asked can be explained in terms of its ability to discriminate between competing cases, thus giving users a unique insight into the recommendation process.     

CROC: A New Evaluation Criterion for Recommender Systems

Evaluation of a recommender system algorithm is a challenging task due to the many possible scenarios in which such systems may be deployed. We have designed a new performance plot called the CROC curve with an associated statistic: the area under the curve. Our CROC curve supplements the widely used ROC curve in recommender system evaluation by discovering performance characteristics that standard ROC evaluation often ignores. Empirical studies on two domains and including several recommender system algorithms demonstrate that combining ROC and CROC curves in evaluation can lead to a more informed characterization of performance than using either curve alone.     

An Expressive Query Language for Product Recommender Systems

We argue that existing approaches to the construction of content-based Product Recommender Systems (Filter-Based Retrieval and Similarity-Based Retrieval) use inadequately expressive query languages. We introduce a new approach, which we call Order-Based Retrieval. We define and exemplify the six operators that constitute its query language. We show how these operators can better support the elicitation of both the customer's initial requirements and refinements to the initial requirements.     

推荐系统中的冷启动问题研究综述

推荐系统能够快捷、准确地定位用户真正需要的信息,解决网络信息过载问题。其中协同过滤推荐技术是推荐系统应用最广泛和成功的技术,但该技术面临冷启动问题的挑战。本文分析冷启动问题的产生原因,阐述研究冷启动问题的意义,重点总结解决冷启动问题的算法现状,分析比较它们的性能差异和各自存在的优缺点,从而便于使用者在解决冷启动问题时对算法的选择和使用。     

Recommender Systems Research: A Connection-Centric Survey

Recommender systems attempt to reduce information overload and retain customers by selecting a subset of items from a universal set based on user preferences. While research in recommender systems grew out of information retrieval and filtering, the topic has steadily advanced into a legitimate and challenging research area of its own. Recommender systems have traditionally been studied from a content-based filtering vs. collaborative design perspective. Recommendations, however, are not delivered within a vacuum, but rather cast within an informal community of users and social context. Therefore, ultimately all recommender systems make connections among people and thus should be surveyed from such a perspective. This viewpoint is under-emphasized in the recommender systems literature. We therefore take a connection-oriented perspective toward recommender systems research. We posit that recommendation has an inherently social element and is ultimately intended to connect people either directly as a result of explicit user modeling or indirectly through the discovery of relationships implicit in extant data. Thus, recommender systems are characterized by how they model users to bring people together: explicitly or implicitly. Finally, user modeling and the connection-centric viewpoint raise broadening and social issues—such as evaluation, targeting, and privacy and trust—which we also briefly address.     

基于位置的社会化网络推荐系统

近年来,基于位置的社会化网络推荐系统逐渐成为位置服务和社会网络分析的活跃课题之一.挖掘用户签到位置轨迹和社交活动数据,提取用户社会活动的地理空间特征模型及其与社会关系的关联性,设计合理的推荐算法,成为当前基于位置的社会化网络推荐系统的主要任务.该文从分析基于位置的社会化网络的结构特征人手,对基于位置的社会化网络推荐系统的基本框架、基于不同网络层次数据挖掘的推荐方法及应用类型等进行前沿概况、比较和分析.最后对有待深入研究的难点和热点进行分析和展望.     

Enhancing Product Recommender Systems on Sparse Binary Data

Commercial recommender systems use various data mining techniques to make appropriate recommendations to users during online, real-time sessions. Published algorithms focus more on the discrete user ratings instead of binary results, which hampers their predictive capabilities when usage data is sparse. The system proposed in this paper, e-VZpro, is an association mining-based recommender tool designed to overcome these problems through a two-phase approach. In the first phase, batches of customer historical data are analyzed through association mining in order to determine the association rules for the second phase. During the second phase, a scoring algorithm is used to rank the recommendations online for the customer. The second phase differs from the traditional approach and an empirical comparison between the methods used in e-VZpro and other collaborative filtering methods including dependency networks, item-based, and association mining is provided in this paper. This comparison evaluates the algorithms used in each of the above methods using two internal customer datasets and a benchmark dataset. The results of this comparison clearly show that e-VZpro performs well compared to dependency networks and association mining. In general, item-based algorithms with cosine similarity measures have the best performance.     

电子商务推荐系统中的协同过滤推荐

电子商务推荐系统中协同过滤已成为目前应用最广泛、最成功的推荐方法。它利用相似用户购买行为也可能相似的特性进行推荐。介绍了与其他方法比较协同过滤方法的优点,然后说明了一些主要的协同过滤实现方法,指出了还需改进和完善的地方以及未来研究的方向。     

Securing Recommender Systems Against Shilling Attacks Using Social-Based Clustering

Recommender systems (RS) have been found supportive and practical in e-commerce and been established as useful aiding services. Despite their great adoption in the user communities, RS are still vulnerable to unscrupulous producers who try to promote their products by shilling the systems. With the advent of social networks new sources of information have been made available which can potentially render RS more resistant to attacks. In this paper we explore the information provided in the form of social links with clustering for diminishing the impact of attacks. We propose two algorithms, CluTr and WCluTr, to combine clustering with "trust" among users. We demonstrate that CluTr and WCluTr enhance the robustness of RS by experimentally evaluating them on data from a public consumer recommender system Epinions.com.     

推荐系统研究进展

推荐系统（recommender system,RS）是当今网络时代的产物,在技术研究和应用方面取得了很多成果。综述了推荐系统领域的研究状况和进展,提出了3个研究阶段,并指出了每个阶段标志性意义的事件。在当前大数据环境下,从数据的角度看推荐,提出了推荐系统新的分类方法,即根据推荐时所使用的数据不同分为7种类别,同时指出了每个类别使用了哪些推荐模型及其优缺点。提出了在大数据环境下进行推荐是未来推荐系统研究的一个大方向,分析了推荐视角下的大数据机制。最后比较和总结了推荐系统的评价指标,给出了未来的主要研究方向和可能的突破点。     

A Generalised Approach to Similarity-Based Retrieval in Recommender Systems

Recommender systems for helping users to selectfrom available products or services areincreasingly common in electronic commerce. Typically in case-based reasoning (CBR)approaches to product recommendation, the itemsrecommended are those that are most similar toa target query representing the elicitedrequirements of the user. Usually in practice,the user is required to specify a singlepreferred value for each attribute in thequery. However, we argue that a more flexibleapproach to requirements elicitation isnecessary to meet the needs of different users,ranging from those who know exactly what theyare looking for to those whose requirements arevague in the extreme. We show how the standardapproach to similarity-based retrieval can begeneralised to support queries in which theuser can enter any number of preferred valuesof a selected attribute, and examine thepotential benefits of the approach.     

一种基于协同过滤技术的在线交友推荐系统的设计与实现

为了满足年轻人在交友择偶方面需求,越来越多的征友网站应运而生.随着网站用户不断增加,根据用户提交的交友要求来进行推荐,往往结果数以千计或万计,要从这里面发现用户感兴趣的对象变得非常困难,我们将协同过滤算法引入交友推荐系统,并设计了一个个性化相似项目的协同过滤算法,根据用户的兴趣进行项目最近邻居查找,大大提高了用户对搜索结果的满意度.     

一种基于协同过滤技术的在线交友推荐系统的设计与实现

为了满足年轻人在交友择偶方面需求,越来越多的征友网站应运而生。随着网站用户不断增加,根据用户提交的交友要求来进行推荐,往往结果数以千计或万计,要从这里面发现用户感兴趣的对象变得非常困难,我们将协同过滤算法引入交友推荐系统,并设计了一个个性化相似项目的协同过滤算法,根据用户的兴趣进行项目最近邻居查找,大大提高了用户对搜索结果的满意度。     

基于案例推理:一种用来改善稀疏性问题的方法

本文对信息过滤（Information filtering）（IF）以及案例推理技术（Case-based Reasoning）（CBR）进行了介绍，并对协同过滤方法中存在的的稀疏性问题，采用案例推理技术进行了一定程度的改善。     

Rascal: A Recommender Agent for Agile Reuse

As software organisations mature, their repositories of reusable software components from previous projects will also grow considerably. Remaining conversant with all components in such a repository presents a significant challenge to developers. Indeed the retrieval of a particular component in this large search space may prove problematic. Further to this, the reuse of components developed in an Agile environment is likely to be hampered by the existence of little or no support materials. We propose to infer the need for a component and proactively recommend that component to the developer using a technique which is consistent with the principles of Agile methodologies. Our RASCAL recommender agent tracks usage histories of a group of developers to recommend to an individual developer components that are expected to be needed by that developer. Unlike many traditional recommender systems, we may recommend items that the developer has actually employed previously. We introduce a content-based filtering technique for ordering the set of recommended software components and present a comparative analysis of applying this technique to a number of collaborative filtering algorithms. We also investigate the relationship between the number of usage histories collected and recommendation accuracy. Our overall results indicate that RASCAL is a very promising tool for allowing developers discover reusable components at no additional cost     

Analysis and Classification of Multi-Criteria Recommender Systems

Recent studies have indicated that the application of Multi-Criteria Decision Making (MCDM) methods in recommender systems has yet to be systematically explored. This observation partially contradicts with the fact that in related literature, there exist several contributions describing recommender systems that engage some MCDM method. Such systems, which we refer to as multi-criteria recommender systems, have early demonstrated the potential of applying MCDM methods to facilitate recommendation, in numerous application domains. On the other hand, a comprehensive analysis of existing systems would facilitate their understanding and development. Towards this direction, this paper identifies a set of dimensions that distinguish, describe and categorize multi-criteria recommender systems, based on existing taxonomies and categorizations. These dimensions are integrated into an overall framework that is used for the analysis and classification of a sample of existing multi-criteria recommender systems. The results provide a comprehensive overview of the ways current multi-criteria recommender systems support the decision of online users.     

推荐技术在电子商务中的应用研究

本文介绍了推荐技术在电子商务中的应用研究概况,详细分析了推荐技术中常用的算法及其性能评估的指标,并对未来推荐技术在电子商务中的研究热点进行了展望。     

查询推荐技术综述

本文介绍了用户搜索中查询推荐技术的相关概念、研究现状;深入分析了目前常见的推荐算法及推荐系统中的隐私保护问题;最后,归纳了查询推荐技术的研究热点。     

基于度量学习的多空间推荐系统

隐式反馈具有数据获取成本小、形式广泛的特点,因此在现代推荐系统中被广泛使用.由于用户的隐式反馈通常是稀疏,不平衡,且含义不明确的.因此,想要准确学习用户和物品之间的复杂交互具有挑战性.传统的基于矩阵分解的推荐方法只能建模用户-物品之间的相似性.同时,矩阵分解使用点积运算作为相似度评估方式,而点积运算不满足三角不等式,即不能将用户-物品相似性传递到用户-用户以及物品-物品的相似性建模.因此,矩阵分解不足以在隐式反馈中充分建模用户和物品的关系.尽管现在有基于隐式反馈使用欧式距离来度量用户-物品相似度的度量学习方法,使得对应的推荐方法能够满足三角不等式.但是,现有的度量方法通常会将每个用户或者物品表示为度量空间中的单个点,进而在单个空间内通过用户-物品之间的距离来表征用户-物品之间的相似性.由于在不同的环境下,用户对于同一种类型的物品的偏好也可能存在差异.基于单个空间的用户、物品嵌入向量有可能无法满足用户具有的多种偏好和物品具有的多种属性,进而限制了推荐系统的性能.为了充分刻画用户和物品,我们尝试从多个侧面对于用户和物品进行表示,并提出了一个基于多空间的度量学习(MML)框架.通过设计整合多个空间相似性的度量方式,我们将用户和物品投影到多个空间中进行细粒度的表示.另外,我们设计了一种经过校准的优化策略,包括经过校准的最大间隔损失函数和经过校准的采样方法.在保持多空间度量学习表示能力的同时,确保框架的有效性.最后,模型通过训练好的用户、物品向量,对于稀疏的用户-物品交互矩阵进行填补.在动态更新空间权重的同时,可以赋予模型新的训练视角,最终实现端到端的训练.通过四个真实世界推荐数据集上进行的大量实验表明,MML可以在Recall和nDCG衡量指标上将目前最优的对比算法提高40%以上.