基于云计算技术的个性化推荐系统

传统的协同过滤推荐技术在大数据环境下存在一定的不足。针对该问题,提出了一种基于云计算技术的个性化推荐方法：将大数据集和推荐计算分解到多台计算机上并行处理。在对经典ItemCF算法MapReduce化后,建立了一个基于Hadoop开源框架的并行推荐引擎,并通过在已商用的英语训练平台上进行学习推荐工作验证了该系统的有效性。实验结果表明,在集群中使用云计算技术处理海量数据,可以大大提高推荐系统的可扩展性。     

Proposal of a recommender system simulator based on a small-world model

This article proposes the development of a software simulator that allows the user to evaluate algorithms for recommender systems. This simulator consists of agents, items, a recommender, a controller, and a recorder, and it locates the agents and allocates the items based on a small-world network. An agent plays the role of a user in the recommender system, and the recommender also plays a role in the system. The controller handles the simulation flow where (1) the recommender recommends items to agents based on the recommendation algorithm, (2) each agent evaluates the items based on the agents’ rating algorithm and using the attributes of each item and agent, and (3) the recorder obtains the results of the rating and evaluation measurements for the recommendation pertaining to such information as precision and recall. This article considers the background of the proposal and the architecture of the simulator.     

MORGAN: a modeling recommender system based on graph kernel

Software and Systems Modeling - Model-driven engineering (MDE) is an effective means of synchronizing among stakeholders, thereby being a crucial part of the software development life cycle. In...     

Folkommender: a group recommender system based on a graph-based ranking algorithm

With the rapid popularity of smart devices, users are easily and conveniently accessing rich multimedia content. Consequentially, the increasing need for recommender services, from both individual users and groups of users, has arisen. In this paper, we present a new graph-based approach to a recommender system, called Folkommender, that can make recommendations most notably to groups of users. From rating information, we first model a signed graph that contains both positive and negative links between users and items. On this graph we examine two distinct random walks to separately quantify the degree to which a group of users would like or dislike items. We then employ a differential ranking approach for tailoring recommendations to the group. Our empirical evaluations on two real-world datasets demonstrate that the proposed group recommendation method performs better than existing alternatives. We also demonstrate the feasibility of Folkommender for smartphones.     

A news-topic recommender system based on keywords extraction

In recent years, internet news has become one of the most important channels for information acquisition, as more and more people read news through internet connected computers, tablets, and smart phones, etc. Owing to the constantly reproduced news, the number of online media increases dramatically and the volume of news also expands rapidly. Consequently, obtaining primary information from the internet is of great interest. This paper presents a news-topic recommender system based on keywords extraction. It is shown that the proposed system is very effective in acquiring specific topics within any specific period of time.     

基于深度学习的矩阵分解推荐模型

通过对深度学习和矩阵分解技术进行结合,设计一个深度神经网络对用户和物品进行特征提取,形成用户隐向量和物品隐向量的方法,计算这两个隐向量的内积得到用户对物品的评分预测.为提高推荐精度,提出使用显式数据和隐式数据并设计新的损失函数能够同时计算这两类数据损失的方法.在两个公开数据集上的实验结果表明,该方法比基线模型在HR和N...     

基于CBR和MADM的多Agent推荐系统

为解决目前基于CBR的推荐系统只考虑属性值全部为精确或全部为非精确数据的情况,提出一种基于MADM的多Agent推荐系统框架。在考虑了属性分类的基础上设计了基于距离的混合数据类型的相似性度量算法及TOPSIS多属性决策方法,设计了该系统各组成部分功能、结构和流程。模拟算例演示了案例推理及多属性决策在本系统的应用过程,结果表明该系统有较好的实用性。     

A query expansion and user profile enrichment approach to improve the performance of recommender systems operating on a folksonomy

In this paper we propose a query expansion and user profile enrichment approach to improve the performance of recommender systems operating on a folksonomy, storing and classifying the tags used to label a set of available resources. Our approach builds and maintains a profile for each user. When he submits a query (consisting of a set of tags) on this folksonomy to retrieve a set of resources of his interest, it automatically finds further “authoritative” tags to enrich his query and proposes them to him. All “authoritative” tags considered interesting by the user are exploited to refine his query and, along with those tags directly specified by him, are stored in his profile in such a way to enrich it. The expansion of user queries and the enrichment of user profiles allow any content-based recommender system operating on the folksonomy to retrieve and suggest a high number of resources matching with user needs and desires. Moreover, enriched user profiles can guide any collaborative filtering recommender system to proactively discover and suggest to a user many resources relevant to him, even if he has not explicitly searched for them.     

Semi-sparse algorithm based on multi-layer optimization for recommender system

Similarity among vectors is basic knowledge required to carry out recommendation and classification in recommender systems, which support personalized recommendation during online interactions. In this paper, we propose a Semi-sparse Algorithm based on Multi-layer Optimization to speed up the Pearson Correlation Coefficient, which is conventionally used in obtaining similarity among sparse vectors. In accelerating the batch of similarity-comparisons within one thread, the semi-sparse algorithm spares out over-reduplicated accesses and judgements on the selected sparse vector by making this vector dense locally. Moreover, a reduce-vector is proposed to restrict using locks on critical resources in the thread-pool, which is wrapped with Pthreads on a multi-core node to improve parallelism. Furthermore, among processes in our framework, a shared zip file is read to cut down messages within the Message Passing Interface package. Evaluation shows that the optimized multi-layer framework achieves a brilliant speedup on three benchmarks, Netflix, MovieLens and MovieLen1600.     

EARS: Emotion-aware recommender system based on hybrid information fusion

Recommender systems suggest items that users might like according to their explicit and implicit feedback information, such as ratings, reviews, and clicks. However, most recommender systems focus mainly on the relationships between items and the user’s final purchasing behavior while ignoring the user’s emotional changes, which play an essential role in consumption activity. To address the challenge of improving the quality of recommender services, this paper proposes an emotion-aware recommender system based on hybrid information fusion in which three representative types of information are fused to comprehensively analyze the user’s features: user rating data as explicit information, user social network data as implicit information and sentiment from user reviews as emotional information. The experimental results verify that the proposed approach provides a higher prediction rating and significantly increases the recommendation accuracy.     

基于客户心理挖掘和预测的推荐系统

基于购物活动表层挖掘的推荐系统的时效性和信息持续性较差。为解决相关问题,提出了基于客户心理挖掘和预测的推荐系统,给出了该系统的解决方案、结构模型以及处理流程。该系统采用多维向量空间存储心理特征数据,并使用贝叶斯算法对客户与商品进行聚类;采用基于功率谱估计的心理特征预测算法生成推荐商品选择。实验结果表明,该系统具有较好的信息持续性,并能够较准确的进行推荐活动。     

基于关联函数的推荐系统相似性研究

针对电子商务推荐系统中相似性的计算,借助关联函数,通过点与区间“距”的引入,在相似度性质的各个性质的保证下,运用vague集理论,构建了一种新的相似性度量公式。一方面满足了推荐系统对相似性计算的要求,另一方面使结果更加符合人们的感性认识,不仅为推荐系统的研究提供了一种新的思路、也为这一领域的研究引入了更为广泛的理论基础。     

Tag recommendation method in folksonomy based on user tagging status

A folksonomy consists of three basic entities, namely users, tags and resources. This kind of social tagging system is a good way to index information, facilitate searches and navigate resources. The main objective of this paper is to present a novel method to improve the quality of tag recommendation. According to the statistical analysis, we find that the total number of tags used by a user changes over time in a social tagging system. Thus, this paper introduces the concept of user tagging status, namely the growing status, the mature status and the dormant status. Then, the determining user tagging status algorithm is presented considering a user’s current tagging status to be one of the three tagging status at one point. Finally, three corresponding strategies are developed to compute the tag probability distribution based on the statistical language model in order to recommend tags most likely to be used by users. Experimental results show that the proposed method is better than the compared methods at the accuracy of tag recommendation.     

Personalized recommender system based on friendship strength in social network services

The rapid growth of social network services has produced a considerable amount of data, called big social data. Big social data are helpful for improving personalized recommender systems because these enormous data have various characteristics. Therefore, many personalized recommender systems based on big social data have been proposed, in particular models that use people relationship information. However, most existing studies have provided recommendations on special purpose and single-domain SNS that have a set of users with similar tastes, such as MovieLens and Last.fm; nonetheless, they have considered closeness relation. In this paper, we introduce an appropriate measure to calculate the closeness between users in a social circle, namely, the friendship strength. Further, we propose a friendship strength-based personalized recommender system that recommends topics or interests users might have in order to analyze big social data, using Twitter in particular. The proposed measure provides precise recommendations in multi-domain environments that have various topics. We evaluated the proposed system using one month's Twitter data based on various evaluation metrics. Our experimental results show that our personalized recommender system outperforms the baseline systems, and friendship strength is of great importance in personalized recommendation.     

A stock market portfolio recommender system based on association rule mining

We propose a stock market portfolio recommender system based on association rule mining (ARM) that analyzes stock data and suggests a ranked basket of stocks. The objective of this recommender system is to support stock market traders, individual investors and fund managers in their decisions by suggesting investment in a group of equity stocks when strong evidence of possible profit from these transactions is available.Our system is different compared to existing systems because it finds the correlation between stocks and recommends a portfolio. Existing techniques recommend buying or selling a single stock and do not recommend a portfolio.We have used the support confidence framework for generating association rules. The use of traditional ARM is infeasible because the number of association rules is exponential and finding relevant rules from this set is difficult. Therefore ARM techniques have been augmented with domain specific techniques like formation of thematical sectors, use of cross-sector and intra-sector rules to overcome the disadvantages of traditional ARM.We have implemented novel methods like using fuzzy logic and the concept of time lags to generate datasets from actual data of stock prices.Thorough experimentation has been performed on a variety of datasets like the BSE-30 sensitive Index, the S&P CNX Nifty or NSE-50, S&P CNX-100 and DOW-30 Industrial Average. We have compared the returns of our recommender system with the returns obtained from the top-5 mutual funds in India. The results of our system have surpassed the results from the mutual funds for all the datasets.Our approach demonstrates the application of soft computing techniques like ARM and fuzzy classification in the design of recommender systems.     

基于三维协同过滤的C2C电子商务推荐系统

个人对个人电子商务(customer to customer,C2C)是目前主流的电子商务模式之一,为解决C2C电子商务网站中特殊的推荐问题,对传统的二维协同过滤方法进行了扩展,提出了能进行卖家和商品组合推荐的三维协同过滤推荐方法,并在此基础上设计了C2C电子商务推荐系统,阐述了该系统的基本架构和推荐过程中的关键运算.该系统利用卖家属性计算卖家相似度,并依据销售关系和卖家相似度对评分数据集进行填充,以解决三维评分数据的稀疏问题;采用协同过滤思想,利用历史评分计算买家相似度,获取最近邻并预测未知评分,最终将预测评分最高的卖家和商品组合推荐给目标买家.实验结果表明,该系统具有较好的推荐效果.     

The recommender system for virtual items in MMORPGs based on a novel collaborative filtering approach

The recommendation system for virtual items in massive multiplayer online role-playing games (MMORPGs) has aroused the interest of researchers. Of the many approaches to construct a recommender system, collaborative filtering (CF) has been the most successful one. However, the traditional CFs just lure customers into the purchasing action and overlook customers’ satisfaction, moreover, these techniques always suffer from low accuracy under cold-start conditions. Therefore, a novel collaborative filtering (NCF) method is proposed to identify like-minded customers according to the preference similarity coefficient (PSC), which implies correlation between the similarity of customers’ characteristics and the similarity of customers’ satisfaction level for the product. Furthermore, the analytic hierarchy process (AHP) is used to determine the relative importance of each characteristic of the customer and the improved ant colony optimisation (IACO) is adopted to generate the expression of the PSC. The IACO creates solutions using the Markov random walk model, which can accelerate the convergence of algorithm and prevent prematurity. For a target customer whose neighbours can be found, the NCF can predict his satisfaction level towards the suggested products and recommend the acceptable ones. Under cold-start conditions, the NCF will generate the recommendation list by excluding items that other customers prefer.     

Privacy aware group based recommender system in multimedia services

Multimedia Tools and Applications - Recommending similar-interest users’ groups in multimedia services is the problem of detecting for each registered user his/her membership to one...     

A novel context-aware recommender system based on a deep sequential learning approach (CReS)

Neural Computing and Applications - With an increase in online longitudinal users’ interactions, capturing users’ precise preferences and giving accurate recommendations have become an...