基于多主题追踪的网络新闻推荐

针对网络新闻推荐系统推荐准确率偏低的问题,提出一种基于多主题追踪的网络新闻推荐算法。基于多主题追踪的推荐算法采用多个用户模型表示用户对不同主题的兴趣,并动态更新用户模型以动态反映用户的兴趣变化。实现了网络新闻推荐系统的核心推荐算法,并在标准路透社新闻数据集(RCV1)上验证了算法的有效性,有效提升了新闻推荐的准确率。     

一种融合用户主题兴趣与用户行为的文档推荐方法

针对单一角度描述用户兴趣存在片面性的问题,该文提出一种融合用户主题兴趣和用户行为的文档推荐方法。一方面从主题兴趣的角度,构建反映用户主题兴趣的主题向量用户模型;另一方面从用户行为的角度,构建反映用户行为兴趣的打分矩阵用户模型。然后,基于上述用户模型提出了两种文档推荐方法,并采用线性加权的方式融合这两种方法,从而实现对用户主题兴趣与用户行为的融合。实验结果表明,该方法的推荐结果好于协同过滤推荐方法和基于内容的推荐方法。     

一个基于搜索结果的个性化推荐系统

搜索引擎返回的结果太多且不能根据用户的兴趣提供检索结果是当前较受关注的问题。把用户兴趣模型和STC聚类算法相结合,提出了改进的STC算法,并提出个性化推荐的策略和兴趣描述更新的方法,实现了一个基于搜索结果的个性化推荐系统(SRPRS)。SRPRS基于改进的STC算法自动组织搜索结果,帮助用户利用主题的方式发现所需的资源。通过实验,分析了SRPRS系统的聚类特性和时间特性。针对搜索引擎的列表显示结果,SRPRS系统在快速查找用户感兴趣的文档上有较好的性能。     

基于兴趣标签的个性化新闻推荐系统

随着互联网的飞速发展所带来的“信息过载”问题使准确的新闻推荐技术变得越来越重要。提出基于兴趣标签的个性化新闻推荐系统,利用Hadoop大数据平台,采用基于项的协同过滤算法,通过收集用户的浏览记录和兴趣标签,挖掘用户的主题兴趣,建立用户的兴趣模型,提高个性化推荐系统的准确性和可扩展性,具有良好的推荐效果。     

人体经络系统中的个性化信息服务研究

人体经络较为复杂,涉及到经络、穴位、疾病、脏腑和针灸等方面的知识,容易导致＂信息迷航＂,且对于不同的用户,信息需求也各不相同。针对该问题,文章系统地研究了人体经络系统中的个性化信息服务,构建了用户兴趣模型,并根据用户对场景的访问次数和停留时间来更新用户的兴趣模型,在此基础上提出基于相似用户兴趣的个性化推荐算法,从而实现为用户提供个性化的信息服务。实验结果表明,系统能根据用户信息及其交互行为,有效地推荐与用户兴趣相关的信息,较好地为用户提供个性化的信息服务。     

面向新闻推荐的用户兴趣模型构建与更新

针对新闻推荐系统中用户兴趣模型构建与用户兴趣漂移问题,提出了一种面向新闻推荐的用户兴趣模型构建与更新方法。首先采用向量空间模型与bisecting K-means聚类算法构建了原始用户兴趣模型;然后以艾宾浩斯遗忘曲线为基础构造了遗忘函数,并以此对用户兴趣模型进行时间加权,从而达到对用户兴趣模型更新的目的。实验以基于用户的协同过滤推荐、基于物品的协同过滤推荐为baseline,实验结果表明所构建的原始用户兴趣模型推荐性能更优,在◢F◣值上提升了4%,更新后的模型与原始模型相比◢F◣值提高了1.3%。     

基于事件本体的新闻个性化推荐

针对传统推荐系统中存在的冷启动、数据稀疏、语义缺乏、推荐精度较低等问题,提出一种基于事件本体的推荐算法。结合新闻的分类结构和新闻语料构建事件本体,对用户浏览的新闻进行要素抽取并构建用户兴趣模型。基于事件本体的分类结构计算新闻事件之间的相似度,通过用户兴趣模型计算用户兴趣相似度,根据事件本体非层次结构的语义半径寻找相关新闻事件。综合事件本体相似度、用户兴趣相似度和非层次结构相似度3个方面得出新闻个性化推荐结果。实验结果表明,该算法的推荐结果优于协同过滤推荐算法和基于内容的推荐算法。     

基于用户潜在时效偏好的推荐算法*

针对推荐系统中用户兴趣的潜在性以及高时效性业务场景下用户兴趣的不稳定性和时间迁移性进行研究,提出一种基于用户潜在时效偏好的推荐方法。通过深入分析用户的历史行为与用户潜在兴趣的关系,提出基于概率主题模型的用户兴趣挖掘方法,避免了传统推荐方式对用户兴趣潜在性的忽略;同时,基于高时效业务对时间敏感性的考虑,结合隐马尔科夫模型对用户兴趣进行实时捕获,发现用户的兴趣迁移序列,并以此提出基于用户时效偏好的推荐方法。最后通过相关实验验证了所提出方法的可行性。     

基于模糊隶属度的个性化网页推荐系统

个性化信息服务越来越成为信息检索领域中研究的热点。针对用户模型的构造问题,文章利用用户浏览过的网页历史记录自动进行文本结构分析,获取网页信息的逻辑表示,将段落作为识别用户兴趣的基本要素,利用段落间的聚类分析和对用户兴趣的表达能力,获取最终的用户兴趣特征向量。提出了一种基于主题描述的二级层次用户模型,并给出了用户模型的动态调整算法,构建了一个基于模糊隶属度的个性化网页推荐系统。模拟实验表明,该用户模型和个性化推荐算法能够有效地提高检索结果的准确性,并且具有良好的适应性。     

融入用户社会关系的协同主题回归模型

协同主题回归（CTR）将概率矩阵分解和主题模型结合应用于推荐系统,在许多推荐应用中取得了成功,但该模型没有考虑用户社会关系对用户兴趣的影响。针对该问题,引入概率链接函数来评估社会关系网络对用户兴趣的影响,并以此约束目标函数。在CTR的基础之上,提出一种融入用户社会关系的协同主题回归模型（USRCTR）,结合用户项目评分信息、项目内容和社会关系网络,构建一个基于分层贝叶斯模型的推荐引擎。在Lastfm数据集上实验表明,与其他几种CTR改进方法对比,该模型的训练时间更短,推荐精度更高。     

Modeling and broadening temporal user interest in personalized news recommendation

User profiling is an important step for solving the problem of personalized news recommendation. Traditional user profiling techniques often construct profiles of users based on static historical data accessed by users. However, due to the frequent updating of news repository, it is possible that a user’s fine-grained reading preference would evolve over time while his/her long-term interest remains stable. Therefore, it is imperative to reason on such preference evaluation for user profiling in news recommenders. Besides, in content-based news recommenders, a user’s preference tends to be stable due to the mechanism of selecting similar content-wise news articles with respect to the user’s profile. To activate users’ reading motivations, a successful recommender needs to introduce “somewhat novel” articles to users.In this paper, we initially provide an experimental study on the evolution of user interests in real-world news recommender systems, and then propose a novel recommendation approach, in which the long-term and short-term reading preferences of users are seamlessly integrated when recommending news items. Given a hierarchy of newly-published news articles, news groups that a user might prefer are differentiated using the long-term profile, and then in each selected news group, a list of news items are chosen as the recommended candidates based on the short-term user profile. We further propose to select news items from the user–item affinity graph using absorbing random walk model to increase the diversity of the recommended news list. Extensive empirical experiments on a collection of news data obtained from various popular news websites demonstrate the effectiveness of our method.     

Rating prediction by exploring user’s preference and sentiment

With the development of e-commerce, shopping on-line is becoming more and more popular. The explosion of reviews have led to a serious problem, information overloading. How to mine user interest from these reviews and understand users’ preference is crucial for us. Traditional recommender systems mainly use structured data to mine user interest preference, such as product category, user’s tag, and the other social factors. In this paper, we firstly use LDA+Word2vec model to mine user interest. Then, we propose a social user sentimental measurement approach. At last, three factors, including user topic, user sentiment and interpersonal influence, are fused into a recommender system (RS) based on probabilistic matrix factorization. We conduct a series of experiments on Yelp dataset, and experimental results show the proposed approach outperforms the existing approaches.     

一种检测兴趣漂移的图结构推荐系统

协同过滤是构造推荐系统最有效的方法之一.其中,基于图结构推荐方法成为近来协同过滤的研究热点.基于图结构的方法视用户和项为图的结点,并利用图理论去计算用户和项之间的相似度.尽管人们对图结构推荐系统开展了很多的研究和应用,然而这些研究都认为用户的兴趣是保持不变的,所以不能够根据用户兴趣的相关变化做出合理推荐.本文提出一种新的可以检测用户兴趣漂移的图结构推荐系统.首先,设计了一个新的兴趣漂移检测方法,它可以有效地检测出用户兴趣在何时发生了哪种变化.其次,根据用户的兴趣序列,对评分项进行加权并构造用户特征向量.最后,整合二部投影与随机游走进行项推荐.在标准数据集MovieLens上的测试表明算法优于两个图结构推荐方法和一个评分时间加权的协同过滤方法.     

一种基于改进型协同过滤算法的新闻推荐系统

将个性化推荐技术运用于新闻阅读应用,以其快速、精准的特点帮助用户快捷获取兴趣新闻,是值得挖掘的研究方向。设计并实现了一种新闻推荐系统,该系统基于用户协同过滤推荐技术,通过收集用户数据,计算阅读耗时因子对用户偏好值进行修正,纳入新闻热度影响并通过热度惩罚用户相似度值;然后基于相似邻居集对用户未阅读的新闻进行Top-N排序得到推荐列表,从而向用户推送其感兴趣的新闻。经测试,原型系统能够实时更新用户兴趣模型,达到推新、推准的效果,各项功能均已达到设计预期目标。     

基于深度学习挖掘用户搜索主题研究

主要研究了基于深度学习技术挖掘用户搜索主题相关的感兴趣内容。通过深度挖掘算法分析用户搜索记录、查询历史以及用户感兴趣的相关文档视为用户搜索主题数据的来源,进而挖掘兴趣主题。挖掘模型主要采用向量空间模型,将用户搜索主题模型表示成用户搜索主题向量形式。形成主题和用户兴趣关系网,用户搜索主题向量的构造过程:选择一组用户查询词,并对它们进行深度挖掘分类,最后用它们构造用户搜索主题特征向量,进而分析用户兴趣点。结合用户随着时间的变化,以及过程中有不用的搜索词,以及无关的搜索噪声词去掉,调整兴趣度,用户搜索主题需要具有更新学习机制,动态跟踪了用户兴趣变化趋势。该用户搜索主题研究过程克服了数据稀疏、类别偏差、扩展性差等缺点。实验结果表明,该模型识别用户搜索主题准确率良好。     

An empirical study on user-topic rating based collaborative filtering methods

User based collaborative filtering (CF) has been successfully applied into recommender system for years. The main idea of user based CF is to discover communities of users sharing similar interests, thus, in which, the measurement of user similarity is the foundation of CF. However, existing user based CF methods suffer from data sparsity, which means the user-item matrix is often too sparse to get ideal outcome in recommender systems. One possible way to alleviate this problem is to bring new data sources into user based CF. Thanks to the rapid development of social annotation systems, we turn to using tags as new sources. In these approaches, user-topic rating based CF is proposed to extract topics from tags using different topic model methods, based on which we compute the similarities between users by measuring their preferences on topics. In this paper, we conduct comparisons between three user-topic rating based CF methods, using PLSA, Hierarchical Clustering and LDA. All these three methods calculate user-topic preferences according to their ratings of items and topic weights. We conduct the experiments using the MovieLens dataset. The experimental results show that LDA based user-topic rating CF and Hierarchical Clustering outperforms the traditional user based CF in recommending accuracy, while the PLSA based user-topic rating CF performs worse than the traditional user based CF.     

Comparative analysis of relevance feedback methods based on two user studies

Rigorous analysis of user interest in web documents is essential for the development of recommender systems. This paper investigates the relationship between the implicit parameters and user explicit rating during their search and reading tasks. The objective of this paper is therefore three-fold: firstly, the paper identifies the implicit parameters which are statistically correlated with the user explicit rating through user study 1. These parameters are used to develop a predictive model which can be used to represent users’ perceived relevance of documents. Secondly, it investigates the reliability and validity of the predictive model by comparing it with eye gaze during a reading task through user study 2. Our findings suggest that there is no significant difference between the predictive model based on implicit indicators and eye gaze within the context examined. Thirdly, we measured the consistency of user explicit rating in both studies and found significant consistency in user explicit rating of document relevance and interest level which further validates the predictive model. We envisage that the results presented in this paper can help to develop recommender and personalised systems for recommending documents to users based on their previous interaction with the system.     

A user-centric evaluation of context-aware recommendations for a mobile news service

Traditional recommender systems provide personal suggestions based on the user’s preferences, without taking into account any additional contextual information, such as time or device type. The added value of contextual information for the recommendation process is highly dependent on the application domain, the type of contextual information, and variations in users’ usage behavior in different contextual situations. This paper investigates whether users utilize a mobile news service in different contextual situations and whether the context has an influence on their consumption behavior. Furthermore, the importance of context for the recommendation process is investigated by comparing the user satisfaction with recommendations based on an explicit static profile, content-based recommendations using the actual user behavior but ignoring the context, and context-aware content-based recommendations incorporating user behavior as well as context. Considering the recommendations based on the static profile as a reference condition, the results indicate a significant improvement for recommendations that are based on the actual user behavior. This improvement is due to the discrepancy between explicitly stated preferences (initial profile) and the actual consumption behavior of the user. The context-aware content-based recommendations did not significantly outperform the content-based recommendations in our user study. Context-aware content-based recommendations may induce a higher user satisfaction after a longer period of service operation, enabling the recommender to overcome the cold-start problem and distinguish user preferences in various contextual situations.     

User interest modeling for social TV-recommender systems based on audiovisual consumption

This paper presents an innovative consumption-modeling system applied to digital TV, able to infer the user interest regarding the TV contents. The user interest inferred is used to feed content recommender systems, and it has been tested in real scenarios involving real users. The modeling system uses as input the TV consumption data and performs an algorithm based on a Hidden Markov Model and Bayesian inference techniques to infer the said user interest. Real data have been picked up in real time to feed our modeling, and the final results have been checked comparing with user’s tastes, which have been expressed through a set of questionnaires and the whole system has been tested in a TV broadcasting scenario with real users. Conclusions show that our system improves the reliability from classic user interest modeling systems (they are mainly based on explicit opinion based methods, which can be intrusive for general users and could show certain deceptive results, as it is described in this paper).     

User comments for news recommendation in forum-based social media

News recommendation and user interaction are important features in many Web-based news services. The former helps users identify the most relevant news for further information. The latter enables collaborated information sharing among users with their comments following news postings. This research is intended to marry these two features together for an adaptive recommender system that utilizes reader comments to refine the recommendation of news in accordance with the evolving topic. This then turns the traditional “push-data” type of news recommendation to “discussion” moderator that can intelligently assist online forums. In addition, to alleviate the problem of recommending essentially identical articles, the relationship (duplicate, generalization, or specialization) between recommended news articles and the original posting is investigated. Our experiments indicate that our proposed solutions provide an improved news recommendation service in forum-based social media.