融合多种数据信息的餐馆推荐模型

餐馆推荐可以利用用户的签到信息、时间上下文、地理上下文、餐馆属性信息以及用户的人口统计信息等挖掘用户的饮食偏好,为用户生成餐馆推荐列表.为了更加有效地融合这些数据信息,提出一种融合了多种数据信息的餐馆推荐模型,该模型首先利用签到信息和时间上下文构建“用户-餐馆-时间片”的三维张量,同时利用其他数据信息挖掘若干用户相似关系矩阵和餐馆相似关系矩阵;然后,在概率张量分解的基础上同时对这些关系矩阵进行分解,并利用BPR优化准则和梯度下降算法进行模型求解;最后得到预测张量,从而为目标用户在不同时间片生成相应的餐馆推荐列表.通过在两个真实数据集上的实验结果表明：相比于目前存在的餐馆推荐模型,所提出的模型有着更好的推荐效果和可接受的运行时间,并且缓解了数据稀疏性对推荐效果的影响.     

基于评分偏好和项目属性的协同过滤算法

针对传统的协同过滤推荐由于数据稀疏性导致物品间相似性计算不准确、推荐准确度不高的问题,文中提出了一种基于用户评分偏好模型、融合时间因素和物品属性的协同过滤算法,通过改进物品相似度度量公式来提高推荐的准确度。首先考虑到不同用户的评分习惯存在差异这一客观现象,引入评分偏好模型,通过模型计算出用户对评分类别的偏好,以用户对评分类别的偏好来代替用户对物品的评分,重建用户-物品评分矩阵;其次基于时间效应,引入时间权重因子,将时间因素纳入评分相似度计算中;然后结合物品的属性,将物品属性相似度和评分相似度进行加权,完成物品最终相似度的计算;最后通过用户偏好公式来计算用户对候选物品的偏好,依据偏好对用户进行top-N推荐。在MovieLens-100K和MovieLens-Latest-Small数据集上进行了充分实验。结果表明,相比已有的经典的协同过滤算法,所提算法的准确率和召回率在MovieLens-100K数据集上提高了9%~27%,在MovieLens-Latest-Small数据集上提高了16%~28%。因此,改进的协同过滤算法能有效提高推荐的准确度,有效缓解数据稀疏性问题。     

Amazon.com recommendations: item-to-item collaborative filtering

Recommendation algorithms are best known for their use on e-commerce Web sites, where they use input about a customer's interests to generate a list of recommended items. Many applications use only the items that customers purchase and explicitly rate to represent their interests, but they can also use other attributes, including items viewed, demographic data, subject interests, and favorite artists. At Amazon.com, we use recommendation algorithms to personalize the online store for each customer. The store radically changes based on customer interests, showing programming titles to a software engineer and baby toys to a new mother. There are three common approaches to solving the recommendation problem: traditional collaborative filtering, cluster models, and search-based methods. Here, we compare these methods with our algorithm, which we call item-to-item collaborative filtering. Unlike traditional collaborative filtering, our algorithm's online computation scales independently of the number of customers and number of items in the product catalog. Our algorithm produces recommendations in real-time, scales to massive data sets, and generates high quality recommendations.     

Reciprocal Recommender Systems: Analysis of state-of-art literature,challenges and opportunities towards social recommendation

There exist situations of decision-making under information overload in the Internet, where people have an overwhelming number of available options to choose from, e.g. products to buy in an e-commerce site, or restaurants to visit in a large city. Recommender systems arose as a data-driven personalized decision support tool to assist users in these situations: they are able to process user-related data, filtering and recommending items based on the user’s preferences, needs and/or behavior. Unlike most conventional recommender approaches where items are inanimate entities recommended to the users and success is solely determined upon the end user’s reaction to the recommendation(s) received, in a Reciprocal Recommender System (RRS) users become the item being recommended to other users. Hence, both the end user and the user being recommended should accept the “matching” recommendation to yield a successful RRS performance. The operation of an RRS entails not only predicting accurate preference estimates upon user interaction data as classical recommenders do, but also calculating mutual compatibility between (pairs of) users, typically by applying fusion processes on unilateral user-to-user preference information. This paper presents a snapshot-style analysis of the extant literature that summarizes the state-of-the-art RRS research to date, focusing on the algorithms, fusion processes and fundamental characteristics of RRS, both inherited from conventional user-to-item recommendation models and those inherent to this emerging family of approaches. Representative RRS models are likewise highlighted. Following this, we discuss the challenges and opportunities for future research on RRSs, with special focus on (i) fusion strategies to account for reciprocity and (ii) emerging application domains related to social recommendation.     

基于标签、得分和偏好时效性的项目推荐方法

网络信息的爆炸式增长使得推荐系统成为一项研究的热点。现存的推荐系统在实际运营中存在各自的缺陷。在web2.0环境下,标签、项目得分以及用户标注项目的时间均包含暗示用户偏好的重要信息,这些信息对提高推荐系统准确度是十分重要的。在借鉴协同过滤思想的基础上,提出综合考虑标签、项目得分和用户偏好时效性的项目推荐模型,并对此模型的体系结构及应用前景进行了分析。     

Personalized news recommendation based on articles chain building

News personalized recommendation has long been a favorite research in recommender. Previous methods strive to satisfy the users by constructing the users’ preference profiles. Traditionally, most of recent researches use users’ reading history (content based) or access pattern (collaborative filtering based) to recommend newly published news to them. In this way, they only considered the relationship between news articles and the users and ignored the context of news report background. In other words, they fail to provide more useful information with considering the progression of the news story chain. In this paper, we propose to define the quality of a news story chain. Besides, we propose a method to construct a news story chain on a news corpus with date information. At last, we use a greedy selection method for filtering the final recommended news articles with considering accuracy and diversity. In this way, we can provide the news articles for users and meet their requirement: after reading the recommended news, the user gains a better understanding of the progression of the news story they read before. Finally, we designed several experiments compared to the state-of-the-art approaches, and the experimental results show that our proposed method significantly improves the accuracy, diversity and NDCG metrics.     

Product recommendation with temporal dynamics

In many E-commerce recommender systems, a special class of recommendation involves recommending items to users in a life cycle. For example, customers who have babies will shop on Diapers.com within a relatively long period, and purchase different products for babies within different growth stages. Traditional recommendation algorithms produce recommendation lists similar to items that the target user has accessed before (content filtering), or compute recommendation by analyzing the items purchased by the users who are similar to the target user (collaborative filtering). Such recommendation paradigms cannot effectively resolve the situation with a life cycle, i.e., the need of customers within different stages might vary significantly. In this paper, we model users’ behavior with life cycles by employing hand-crafted item taxonomies, of which the background knowledge can be tailored for the computation of personalized recommendation. In particular, our method first formalizes a user’s long-term behavior using the item taxonomy, and then identifies the exact stage of the user. By incorporating collaborative filtering into recommendation, we can easily provide a personalized item list to the user through other similar users within the same stage. An empirical evaluation conducted on a purchasing data collection obtained from Diapers.com demonstrates the efficacy of our proposed method.     

一种融合聚类与用户兴趣偏好的协同过滤推荐算法

协同过滤推荐算法可以根据已知用户的偏好预测其可能感兴趣的项目,是现今最为成功、应用最广泛的推荐技术。然而,传统的协同过滤推荐算法受限于数据稀疏性问题,推荐结果较差。目前的协同过滤推荐算法大多只针对用户-项目评分矩阵进行数据分析,忽视了项目属性特征及用户对项目属性特征的偏好。针对上述问题,提出了一种融合聚类和用户兴趣偏好的协同过滤推荐算法。首先根据用户评分矩阵与项目类型信息,构建用户针对项目类型的用户兴趣偏好矩阵;然后利用K-Means算法对项目集进行聚类,并基于用户兴趣偏好矩阵查找待估值项所对应的近邻用户;在此基础上,通过结合项目相似度的加权Slope One算法在每一个项目类簇中对稀疏矩阵进行填充,以缓解数据稀疏性问题;进而基于用户兴趣偏好矩阵对用户进行聚类;最后,面向填充后的评分矩阵,在每一个用户类簇中使用基于用户的协同过滤算法对项目评分进行预测。实验结果表明,所提算法能够有效缓解原始评分矩阵的稀疏性问题,提升算法的推荐质量。     

HYBRID PROFILING FOR HYBRID MULTICRITERIA RECOMMENDATION BASED ON IMPLICIT MULTICRITERIA INFORMATION

Multicriteria recommender systems typically gather the user preferences by asking a user to rate different aspects of an item on a sliding scale explicitly. However, this approach could possibly cause intrusiveness and conflict on user preferences. For example, an individual's preference on each aspect of an item may conflict with an overall preference. To overcome such limitations, we proposed the hybrid profiling framework to generate a set of useful implicit dataset to support multicriteria recommender systems. We also proposed two hybrid multicriteria recommendation approaches, namely the user-attribute-based (UAB) and the user-item matching (UIM) to improve recommendation accuracy. Finally, we conducted experiments to confirm the efficiency of the proposed approaches. The experiments show that the profiling framework and two hybrid recommendation approaches can alleviate the problem in an intrusive manner and decrease the degree of preference conflict without decreasing the accuracy of the recommendation. They also show that our proposed hybrid multicriteria recommendation approaches can significantly outperform both the traditional collaborative filtering and the simple multicriteria filtering approaches.     

结合项目区分用户兴趣度的协同过滤算法

协同过滤是推荐系统中应用最为广泛的方法.基于用户的协同过滤算法在计算用户相似性时,对不同的项目给予相同的权重,然而在现实中不同项目对刻画用户的兴趣所起作用不同,从而基于用户的协同过滤会造成对流行的项目打分高的问题,而不能真正反映用户的兴趣.本文提出项目的区分用户偏好值概念,从而更好的刻画了用户的兴趣,在此基础上,改进了计算用户相似度的方法,使推荐算法具有较高准确度.算法在标准数据集MovieLens上进行了测试,实验表明了算法的有效性.     

An effective collaborative filtering algorithm based on user preference clustering

Collaborative filtering is one of widely used recommendation approaches to make recommendation services for users. The core of this approach is to improve capability for finding accurate and reliable neighbors of active users. However, collected data is extremely sparse in the user-item rating matrix, meanwhile many existing similarity measure methods using in collaborative filtering are not much effective, which result in the poor performance. In this paper, a novel effective collaborative filtering algorithm based on user preference clustering is proposed to reduce the impact of the data sparsity. First, user groups are introduced to distinguish users with different preferences. Then, considering the preference of the active user, we obtain the nearest neighbor set from corresponding user group/user groups. Besides, a new similarity measure method is proposed to preferably calculate the similarity between users, which considers user preference in the local and global perspectives, respectively. Finally, experimental results on two benchmark data sets show that the proposed algorithm is effective to improve the performance of recommender systems.     

Flickr group recommendation with auxiliary information in heterogeneous information networks

Over the past few years, the appropriate utilization of user communities or image groups in social networks (i.e., Flickr or Facebook) has drawn a great deal of attention. In this paper, we are particularly interested in recommending preferred groups to users who may favor according to auxiliary information. In real world, the images captured by mobile equipments explicitly record a lot of contextual information (e.g., locations) about users generating images. Meanwhile, several words are employed to describe the particular theme of each group (e.g., “Dogs for Fun Photos” image group in Flickr), and the words may mention particular entities as well as their belonging categories (e.g., “Animal”). In fact, the group recommendation can be conducted in heterogeneous information networks, where informative cues are in general multi-typed. Motivated by the assumption that the auxiliary information (visual features of images, mobile contextual information and entity-category information of groups in this paper) in heterogeneous information networks will boost the performance of the group recommendation, this paper proposes to combine auxiliary information with implicit user feedback for group recommendation. In general, the group recommendation in this paper is formulated as a non-negative matrix factorization (NMF) method regularized with user–user similarity via visual features and heterogeneous information networks. Experiments show that our proposed approach outperforms other counterpart recommendation approaches.     

Music recommendation hybrid system for improving recognition ability using collaborative filtering and impression words

Music therapy for improving recognition ability may be more effective when the favorite music of each person is adopted. In the proposed system, first, the recommendation process using collaborative filtering is terminated when no users in the reference list have the same preference of recommended music as that of a new user. Then, the second recommendation process finds the most similar music, from the scores for impression words, to those successfully recommended among music not recommended up to the moment. The average number of recommended songs for each user by the proposed system was 12.1, whereas that of collaborative filtering was 4.3. The recommendation accuracy of the proposed system was 70.2 %, whereas that of collaborative filtering was 62.1 %. The ratings of songs can be added on a user-by-user basis in the recommendation process, and this increased number of cases improves the recommendation accuracy and increases the number of recommended songs.     

User-controllable personalization: A case study with SetFusion

In this research we investigated the role of user controllability on personalized systems by implementing and studying a novel interactive recommender interface, SetFusion. We examined whether allowing the user to control the process of fusing or integrating different algorithms (i.e., different sources of relevance) resulted in increased engagement and a better user experience. The essential contribution of this research stems from the results of a user study (N=40) of controllability in a scenario where users could fuse different recommendation approaches, with the possibility of inspecting and filtering the items recommended. First, we introduce an interactive Venn diagram visualization, which combined with sliders, can provide an efficient visual paradigm for information filtering. Second, we provide a three-fold evaluation of the user experience: objective metrics, subjective user perception, and behavioral measures. Through the analysis of these metrics, we confirmed results from recent studies, such as the effect of trusting propensity on accepting the recommendations and also unveiled the importance of features such as being a native speaker. Our results present several implications for the design and implementation of user-controllable personalized systems.     

基于加权三部图的协同过滤推荐算法

针对基于用户的协同过滤算法推荐结果过度集中在热门物品,导致多样性和新颖性较低、覆盖率较小的问题,文中提出基于加权三部图的协同过滤推荐算法.在分析数据稀疏和附加信息较少的基础上引入标签信息,可同时反映用户兴趣和物品属性,利用用户、物品和标签三元关系构建三部图.通过三部图网络映射到单模网络的方法获得用户偏好度,构建用户偏好...     

基于重叠度和双重属性的协同过滤推荐算法

协同过滤是现行推荐系统中应用最广泛也是最成功的推荐技术之一,然而传统的协同过滤推荐算法存在着邻居选取片面性和推荐精度低的问题。针对上述问题,提出了一种基于重叠度和双重属性的协同过滤推荐算法。首先基于相似度和重叠度的共同计算结果选取推荐对象集;然后提出了双重属性的概念,分别计算推荐用户的信任度和目标项目的受欢迎度;最后兼顾两个群体,根据用户和项目两方面的评分信息完成对目标用户的推荐。实验结果证明该算法较传统的协同过滤推荐算法在邻居选取和推荐质量方面均有显著的提高。     

一种基于项目属性评分的协同过滤推荐算法

协同过滤是电子商务推荐系统中应用最成功的推荐技术之一,但面临着严峻的用户评分数据稀疏性和推荐精度低等问题。针对数据稀疏性高和单一评分导致的推荐精度低等问题,提出一种基于项目属性评分的协同过滤推荐算法。首先通过均值法或缩放法构造用户-项目属性评分矩阵将单一评分转化为多评分;其次基于每个属性评分矩阵,计算用户间的偏好相似度,得到目标用户的偏好最近邻居集;然后针对每个最近邻居集,在用户-项目评分矩阵上完成对目标用户的初步评分预测;最后,将多个初步预测评分加权求和作为综合评分,完成推荐。在Movie Lens扩展数据集上的实验结果表明,该算法能有效提高推荐精度。     

深度学习方法在兴趣点推荐中的应用研究综述

在基于位置的社交网络（LBSN）中,用户可以在兴趣点（POI）进行签到以记录行程,也可以与其他用户分享自身的感受并形成社交好友关系。POI推荐是LBSN提供的一项重要服务,其可以帮助用户快速发现感兴趣的POI,也有利于POI提供商更全面地了解用户偏好,并有针对性地提高服务质量。POI推荐主要基于对用户历史签到数据以及用户生成内容、社交关系等信息的分析来实现。系统归纳POI推荐中所面临的时空序列特征提取、内容社交特征提取、多特征整合、数据稀疏性问题处理这4个方面的挑战,分析在POI推荐中使用深度学习方法解决上述问题时存在的优势以及不足。在此基础上,展望未来通过深度学习提高POI推荐效果的研究方向,即通过增量学习加速推荐模型更新、使用迁移学习缓解冷启动问题以及利用强化学习建模用户动态偏好,从而为实现效率更高、用户体验质量更好的推荐系统提供新的思路。     

基于商品属性值和用户特征的协同过滤推荐算法

为了提高用户相似度计算精度和推荐准确性,缓解数据稀疏性,提出一种基于商品属性值和用户特征的协同过滤推荐算法。该算法首先从用户对商品属性值的偏好出发,计算用户对商品属性值的评分分布和评分期望值,得到用户-属性值评分矩阵;同时利用数据相似性度量方法寻找用户特征邻居,填充用户-属性值评分稀疏矩阵,进而得出目标用户偏好的最近邻居集;计算用户对未评属性值的评分,将目标用户对商品所有属性值评分的均值进行排序,形成该用户的Top-N推荐列表。采用Movie Lens和Book Crossing数据集进行实验,结果表明该算法在缓解数据稀疏性问题上效果较好,推荐精度显著提高。     

融合用户特征优化聚类的协同过滤算法

针对推荐系统领域中应用最广泛的协同过滤推荐算法仍伴随着数据稀疏性、冷启动和扩展性问题,基于用户冷启动和扩展性问题,提出了基于改进聚类的PCEDS(pearson correlation coefficient and euclidean distance similarity)协同过滤推荐算法。首先针对用户属性特征,采用优化的K-means聚类算法对其聚类,然后结合基于信任度的用户属性特征相似度模型和用户偏好相似度模型,形成一种新颖的PCEDS相似度模型,对聚类结果建立预测模型。实验结果表明:提出的PCEDS算法比传统的协同过滤推荐算法在均方根误差(RMSE)上降低5%左右,并且推荐准确率(precision)和召回率(recall)均有明显提高,缓解了冷启动问题,同时聚类技术可以节省系统内存计算空间,从而提高了推荐效率。