Hybrid Location-based Recommender System for Mobility and Travel Planning

In recent times, the modern developments of internet technologies and social networks have attracted global researchers to explore the recommender systems for generating personalized location-based services. Recommender Systems (RSs) as proven decision support tools have gained immense popularity to solve information overloading problem among various real-time applications of e-commerce, travel and tourism, movies and e-learning. RSs emerge as a popular and reliable information filtering approach that is capable of suggesting relevant items, movies, and locations to the active target user based on dynamic preferences and interests. Beyond the development of many feature-rich recommendation algorithms, the need for a better full-fledged RS to produce precise and highly relevant recommendations based on ratings and preferences provided by the target user is very high. With the specific focus to the travel domain, the global research community has been involved in the development of a complete travel recommender system that is immune to the sparsity and cold start problems. In this paper, we present a new Hybrid Location-based Travel Recommender System (HLTRS) through exploiting ensemble based co-training method with swarm intelligence algorithms to enhance the personalized travel recommendations. The proposed HLTRS is experimentally validated on the real-world large-scale dataset, and we have made an extensive user study to determine the ability of developed RS to produce user satisfiable recommendations in real-time scenarios. The obtained results and analyses demonstrate the improved performance of the proposed Hybrid Location-based Travel Recommender System over existing baselines of recommender systems research.

     

The impact of multi-criteria ratings in social networking sites on the performance of online recommendation agents

Recommender Systems (RSs) have played an important role in online retailing portals and customers’ decision-making processes. Recommender systems that are based on the conventional Collaborative Filtering (CF) approach rely on single customers’ ratings on retailing websites. Multi-criteria CF (MCCF) approaches that rely on multi-aspects of the products have provided more reliable and effective recommendations on retailing websites. However, these approaches should be improved in terms of accuracy by solving sparsity issues and incorporating criteria ratings. In addition, most of the recommendation agents that are based on MCCF cannot learn automatically from the features of the products to model customers’ preferences and generate accurate recommendations on retailing websites. Besides, although previous studies have utilized single and multi-criteria ratings in recommendation agents of tourism websites, still, if there is a lack of ratings of items, most of these systems will fail to generate accurate recommendations to users. In this research, we develop a new recommendation agent based on a MCCF approach to effectively improve the performance of previous recommendation systems for tourism websites. The results demonstrated that the method can predict the most relevant products to users, particularly when the dataset is sparse.     

Personalized privacy protection method for group recommendation

To address the problem that most of the existing privacy protection methods can not satisfy the user’s personalized requirements very well in group recommendation,a user personalized privacy protection framework based on trusted client for group recommendation (UPPPF-TC-GR) followed with a group sensitive preference protection method (GSPPM) was proposed.In GSPPM,user’s historical data and privacy preference demands were collected in the trusted client,and similar users were selected in the group based on sensitive topic similarity between users.Privacy protection for users who had privacy preferences in the group was realized by randomization of cooperative disturbance to top k similar users.Simulation experiments show that the proposed GSPPM can not only satisfy privacy protection requirements for each user but also achieve better performance.     

Novelty‐driven recommendation by using integrated matrix factorization and temporal‐aware clustering optimization

With the rapid proliferation of information and communication technology (ICT), the vast amount of available data creates information overload. The Websites and e‐commerce applications employ several information filtering methods such as personalized recommender system to manage the information overload. The recommender system assists the users in obtaining the desired list of products based on their interest. Several existing research works focus on the novelty or unexpectedness in the recommendation list while ensuring the quality to enhance the recommendation mechanism. It is essential to balance the unexpected and useful products or services to generate the satisfactory personalized recommendations with novelty. Thus, this paper proposes a novelty‐driven movie suggestion using integrated matrix factorization and temporal‐aware clustering optimization (NOMINATE). The proposed approach determines the personalized preferences through probabilistic matrix factorization (PMF) and contextually updates the rules and extracts the user preferences based on the inherent features of both the users and movies with temporal information. The NOMINATE approach also suggests the novelty‐driven, and desired top‐N movies to the users through the K‐means, and particle swarm optimization (PSO)‐based clustering algorithm with the help of LOD source. To identify the expert users, the NOMINATE approach applies the K‐means and PSO‐based clustering algorithm to enrich the personalized features of the users. Moreover, it integrates the relevant features with the preferred set of features for each user using the LOD source and decides a set of optimal preferences of the users. Finally, the NOMINATE approach generates the top‐N recommendation list for the corresponding user through ranking method. The experiment results stipulate that the NOMINATE approach personalize the top‐N movie recommendations with high performance regarding accuracy and novelty when compared with the existing recommendation method.     

个性化特征的电子商务智能推荐系统

以准确向用户推荐商品,提升电子商务网站销售量为目标,设计基于个性化特征的电子商务智能推荐系统。系统以个性化推荐引擎为核心,采集交易事务、商品特征、用户评价等数据,利用基于个性化特征的协同过滤推荐算法计算商品间相似度,确定新商品的近邻,根据近邻用户对新商品的评价结果选择商品进行推荐。测试结果表明,该系统的电子商务商品推荐误差小,有利于提升电子商务网站交易率,而且电子商务商品推荐性能明显优于其他推荐系统。     

E-Learning系统的个性化推荐方法研究

以E-Learning系统建设为背景,通过采用文献查找、调查研究等方法探讨个性化推荐理论的内涵,并结合当前建设中的E-Learning系统,分析了目前常用的个性化推荐策略,并进行介绍比较和分析以后,总结经验,以应用于E-Learning系统的建设。提出适合于E-learning系统建设的个性化推荐策略:采用关联规则推荐策略和协同过滤技术,基于WEB技术建立一个虚拟学习系统,利用推荐算法,结合用户需求,将学习的资源、学习活动和学习策略进行整合,向用户推荐完整的满足用户需求的E-Learning学习方案。     

基于时空上下文信息的POI推荐模型研究

随着基于位置的社交网络(LBSN)技术的快速发展,为移动用户提供个性化服务的兴趣点(POI)推荐成为关注重点。由于POI推荐面临着数据稀疏、影响因素多和用户偏好复杂的挑战,因此传统的POI推荐往往只考虑签到频率以及签到时间和地点对用户的影响,而忽略了签到序列中用户前后行为的关联影响。为了解决上述问题,该文通过序列的表示考虑签到数据的时间影响和空间影响,建立了时空上下文信息的POI推荐模型(STCPR),为POI推荐提供了更精准的个性化偏好。该模型基于序列到序列的框架下,将用户信息、POI信息、类别信息和时空上下文信息进行向量化后嵌入GRU网络中,同时利用了时间注意力机制、全局和局部的空间注意力机制来综合考虑用户偏好与变化趋势,从而向用户推荐感兴趣的Top-N的POI。该文通过在两个真实的数据集上实验来验证模型的性能。实验的结果表明,该文所提出的方法在召回率(Recall)和归一化折损累计增益(NDCG)方面优于几种现有的方法。     

基于置信用户偏好模型的电视推荐系统

基于用户偏好的电视节目个性化推荐是一种内容的推荐算法。其中用户偏好的不确定性和描述上的模糊性是用户模型建立的难点。在此首先通过对样本用户过往观看记录数据进行分析,发现用户偏好存在一定的时不变性。把偏好在一定时间内不发生变化的用户称作置信用户,在这个基础上,建立基于节目特征向量空间的用户偏好模型,并提出基于用户偏好度模型的推荐算法。该算法通过用户观看视频的历史记录得到用户的偏好模型,并基于该偏好模型向用户推荐节目。仿真实验证明了算法的收敛性和有效性。     

交互电视中基于本体的个性化节目协同推荐

提出一种在Web-TV环境中,拥有较强个性化和交互特性的基于本体的电视节目协同推荐方法。采用隐式和显式两种方法估计用户对其已收看节目的喜好程度,并根据用户收看电视节目的四条性质,提出隐式估计评分值的核心公式。在协同推荐时,利用节目本体中各元素的语义相似性,根据已经得到的评分值推测用户对未收看节目的评分值,解决了协同推荐的稀疏性缺点,并且在计算用户之间的相似度时,还考虑了用户的个人属性。最后还提出了实现了该算法的原型系统。     

Performance improvement for recommender systems using ontology

Recommender systems have emerged in the e-commerce domain and have been developed to actively recommend appropriate items to online users. The use of recently developed hybrid recommendation systems has helped overcome the main drawbacks of Content-Based Filtering (CBF) and Collaborative Filtering (CF). In hybrid recommendation systems that combine CF and CBF, the CF part uses two methods, including memory- and model-based approaches. Both approaches have some advantages and disadvantages for item recommendation. Sparsity has been one of the main difficulties associated with these approaches, whereas recommendation with high accuracy has been one of the important advantages of the memory-based approach. However, this approach is not scalable for current recommendation systems as their databases include huge numbers of items and users. In contrast, the model-based approach generates recommendations with low accuracy but is scalable for large databases in e-commerce recommender systems. Accordingly, to address this problem and take advantage of both approaches, in this work, we propose a new hybrid recommendation method and evaluate it using a real-world dataset. The aim is to improve efficiency and accuracy by designing a heuristic hybrid recommender method that combines memory-based and model-based approaches. Specifically, we use ontology in the CF part and improve ontology structure by eliminating uniformity of edges of the hierarchical relation between concepts (IS-A relation) in item ontology in the CBF part. Ontology structure is considered for improving accuracy; according to this, a new method for measuring semantic similarity that is more accurate than the traditional methods is presented. This new method can enhance the accuracy of CF and CBF in our method. In addition, the number of searches required to find similar clusters and neighbor users of the target user is decreased significantly using ontology, enhanced clustering and the new proposed algorithm. We evaluate the proposed method using a real-world dataset. The experimental results show that our method is more scalable and accurate than the benchmark k-Nearest Neighbor (k-NN) and model-based recommendation methods.     

E—Learning系统的个性化推荐方法研究

以E—Learning系统建设为背景,通过采用文献查找、调查研究等方法探讨个性化推荐理论的内涵,并结合当前建设中的E—Learning系统,分析了目前常用的个性化推荐策略,并进行介绍比较和分析以后,总结经验,以应用于E—Learning系统的建设。提出适合于E—learning系统建设的个性化推荐策略：采用关联规则推荐策略和协同过滤技术,基于WEB技术建立一个虚拟学习系统,利用推荐算法,结合用户需求,将学习的资源、学习活动和学习策略进行整合,向用户推荐完整的满足用户需求的E—Learning学习方案。     

考虑多层次潜在特征的个性化推荐模型

个性化推荐已成为解决信息过载的最有效手段之一,也是海量数据挖掘研究领域的热点技术。然而传统推荐算法往往只使用用户对物品的评分信息,而缺少对用户与物品潜在特征的综合考虑。基于因子分解机、宽神经网络、交叉网络和深度神经网络的融合,提出一种新的考虑多层次潜在特征的模型,可以提取用户与物品的浅层潜在特征、低阶非线性潜在特征、线性交叉潜在特征以及高阶非线性潜在特征。在4个常用的数据集上的实验结果表明,考虑用户与物品多层次潜在特征可以有效提高个性化推荐的预测精度。最后,研究了嵌入层维度以及神经元数量等因素对新模型预测性能的影响。     

On recommendation-aware content caching for 6G: An artificial intelligence and optimization empowered paradigm

Recommendation-aware Content Caching (RCC) at the edge enables a significant reduction of the network latency and the backhaul load, thereby invigorating ubiquitous latency-sensitive innovative services. However, the effectiveness of RCC strategies is highly dependent on explicit information as regards subscribers’ content request patterns, the sophisticated caching placement policy, and the personalized recommendation tactics. In this article, we investigate how the potentials of Artificial Intelligence (AI) and optimization techniques can be harnessed to address those core issues and facilitate the full implementation of RCC for the upcoming intelligent 6G era. Towards this end, we first elaborate on the hierarchical RCC network architecture. Then, the devised AI and optimization empowered paradigm is introduced, whereas AI and optimization techniques are leveraged to predict the users’ content preferences in real-time situations with the assistance of their historical behavior data and determine the cache pushing and recommendation decision, respectively. Through extensive case studies, we validate the effectiveness of AI-based predictors in estimating users’ content preference and the superiority of optimized RCC policies over the conventional benchmarks. At last, we shed light on the opportunities and challenges in the future.     

融合多权重因素的低秩概率矩阵分解推荐模型

针对个性化推荐精度较低、对冷启动敏感等问题,该文提出一种融合多权重因素的低秩概率矩阵分解推荐模型MWFPMF.模型利用给定的社交网络构建信任网络,借助Page rank算法和信任传递机制求取用户间信任度;基于Page rank计算用户社会地位,利用活动评分和评分时间修正用户间关系权重;引入词频-逆文本频率技术(TF-I...     

Adaptive and personalized multimedia content delivery for disabled users in Internet TV

This paper aims at the delivery of adaptive and personalized multimedia content in interactive Internet Protocol TeleVision (IPTV) environments, using programmable IP services through the MPEG-21 standard, also supporting the features for users with disabilities. Moreover, we propose a system that adapts to users’ preferences using profile separation, not only for individual users but also for user groups as a whole. The system takes advantage of explicit and implicit information through the users’ interaction with the IPTV environment, while the profile reflects groups of similar users, thus dropping the time needed for matching user patterns and profiles when forming a recommendation. The system works in conjunction with a simulation platform acting as an interaction interface between the IPTV architecture and the prospective viewer. Based on this, interactivity in IPTV is faced through metadata and adaptation.     

BPR-UserRec:a personalized user recommendation method in social tagging systems

Social tagging is one of the most important characteristics of Web 2.0 services, and social tagging systems (STS) are becoming more and more popular for users to annotate, organize and share items on the Web. Moreover, online social network has been incorporated into social tagging systems. As more and more users tend to interact with real friends on the Web, personalized user recommendation service provided in social tagging systems is very appealing. In this paper, we propose a personalized user recommendation method, and our method handles not only the users’ interest networks, but also the social network information. We empirically show that our method outperforms a state-of-the-art method on real dataset from Last.fm dataset and Douban.     

融合用户信任度和相似度的基于核心用户抽取的鲁棒性推荐算法

推荐系统可以方便地帮助人们做出决策,然而,目前很少有研究考虑到剔除不相关噪声用户的影响,保留少量核心用户做推荐。该文提出基于信任关系和兴趣相似度的核心用户抽取的新方法。首先计算所有用户对之间的信任度和兴趣相似度并且排序,然后根据用户在最近邻列表中出现的频率和位置权重两种策略选择候选核心用户集合,最后利用用户的推荐能力筛选出最终的核心用户并且做推荐。实验表明利用核心用户做推荐的有效性,并且证明了利用20%的核心用户做推荐,可以达到超过90%的准确性,而且利用核心用户做推荐能很好地抵御托攻击对推荐系统造成的负面影响。     

IPTV视频个性化推荐方案

分析了IPTV视频领域个性化推荐需求,以“虚拟视频用户”为基础建立了IPTV视频用户画像,构建了“离线批处理数据分析+在线流式推荐引擎”架构的个性化推荐系统,实现了IPTV视频的个性化推荐。验证结果证明该方案是大数据技术在提升用户IPTV使用体验方面的有益尝试。     

面向时序感知的多类别商品方面情感分析推荐模型

电子商务网站中的评论数据隐含着商品特征和用户情感,现有基于方面情感分析的推荐研究大多通过抽取同一类别商品评论数据中用户对商品不同方面的情感来捕捉用户方面偏好,忽略了不同类别商品有不同方面以及用户的方面偏好随时间变化的特点。对此,该文提出一种面向时序感知的多类别商品方面情感分析推荐模型,该模型对用户、商品类别、商品、商品方面、方面情感和时间统一建模,以发现用户对不同类别商品的方面偏好随时间变化的特点,并据此做出推荐。该模型能够推断用户在任意时间对商品的方面偏好,从而为用户提供可解释的推荐。两个真实数据集的实验结果表明,与其它基于时间或方面情感分析的推荐模型相比,该文提出的模型在top-N推荐准确率和召回率评价指标上均获得显著改善。     

Context-based Ontology-driven Recommendation Strategies for Tourism in Ubiquitous Computing

Tourism is an information-intensive business. At present, there are a lot of information and tourism resources available on the internet that lead to low searching efficiency and effectiveness, the user may get too many seeking results but not related to his interest, or few results than his expected. The user can know clearly what he wants, but sometime the user doesn’t know what kind information he needs. User’s demand can be formulated as direct demand and potential preference. At the same time, the study shows that there is strong relationship between the traveler’s potential preference and the characteristics of tourism resources. In order to solve the information overload challenge, recommendation services are increasingly emerging. Currently, recommendation methods focus on dealing with personalized matching based on the user preference. However, these methods skip the user’s direct demand. In this paper, we propose ontology-driven recommendation strategies based on user’s context. The strategies use ontology to describe and integrate tourism resources, achieve the goal of associating user’s direct needs and his potential preference as the context in recommendation. Moreover, theoretical analysis and experiments show that the proposed approach is feasible, the results of the evaluation are discussed.