Competence-based recommender systems: a systematic literature review

ABSTRACT

Competence-based learning is increasingly widespread in many institutions since it provides flexibility, facilitates the self-learning and brings the academic and professional worlds closer together. Thus, the competence-based recommender systems emerged taking the advantages of competences to offer suggestions (performance of a learning experience, assistance of an expert or recommendation of a learning resource) to the user (learner or instructor). The objective of this work is to conduct a new Systematic Literature Review (SLR) concerning competence-based recommender systems to analyse in relation to their nature and assessment of competences an others key factors that provide more flexible and exhaustive recommendations. To do so, a SLR research methodology was followed in which 25 competence-based recommender systems related to learning or instruction environments were classified according to multiple criteria. We evaluate the role of competences in these proposals and enumerate the emerging challenges. Also a critical analysis of current proposals is carried out to determine their strengths and weakness. Finally, future research paths to be explored are grouped around two main axes closely interlinked; first about the typical challenges related to recommender systems and second, concerning ambitious emerging challenges.     

Context-aware recommender systems in mobile environment: On the road of future research

Recommender systems have recently been singled out as a fascinating area of research, owing to the technological progress in mobile devices, such as smartphones and tablets, as well as to the rapid growth of social networking. In this respect, the main purpose of recommender systems is to suggest items that help users to make decisions from a large number of possible actions such as what place to visit, what movie to watch, or which friend to add to a social network system. In mobile environment, many personal, social and environmental contextual factors can be integrated into the recommendation process in order to provide the correct recommendation to a special user, at the perfect moment, in the appropriate location based on his/her emotional state, his/her current activity and past behavior. This paper provides an overview of context-aware recommender systems in mobile environment. The objective of this systematic review is to investigate the current state of the art in context-aware recommender systems and classify the reviewed research papers. This study aims equally to identify the possible future directions in this research area.     

Framework to improve e-learner satisfaction and further strengthen e-learning implementation

In this study, a framework has been designed to guide institutions to better improve learner satisfaction and further strengthen their e-learning implementation. Undergraduate participants (n = 600) completed an online survey of 132 items. This article will first report on the development and validation of an instrument that attempts to reveal factors that affect user satisfaction, and then a multiple regression analysis and a path analysis help further investigate which factors can significantly predict learner satisfaction. The factor analysis identified 14 different factors. These factors were further categorized by the researchers into 6 dimensions i.e. learner dimension, instructor’s dimension, course dimension, technology dimension, design dimension, and the environment dimension. The multiple regression analysis showed that e-learners satisfaction can mostly be predicted by learner interaction with others. Findings of this research will help institutions by providing them with psychometric properties that add pedagogical value to e-courses.     

基于增强学习的旅行计划推荐系统

目前旅游和观光事业通过推荐系统帮助用户进行互动式对话获得目标。已有的推荐系统尽管互动性已经增强,但仍采用互动策略,在设计阶段需要指定先验。针对该问题,提出一个普遍适用的模型,基于增强学习技术设计一种旅行会话推荐系统,描述推荐系统采用的方法,总结一些关键问题。分析结果表明,该系统可自动学习自适应交互策略,     

Knowledge-based recommendation: a review of ontology-based recommender systems for e-learning

Recommender systems in e-learning domain play an important role in assisting the learners to find useful and relevant learning materials that meet their learning needs. Personalized intelligent agents and recommender systems have been widely accepted as solutions towards overcoming information retrieval challenges by learners arising from information overload. Use of ontology for knowledge representation in knowledge-based recommender systems for e-learning has become an interesting research area. In knowledge-based recommendation for e-learning resources, ontology is used to represent knowledge about the learner and learning resources. Although a number of review studies have been carried out in the area of recommender systems, there are still gaps and deficiencies in the comprehensive literature review and survey in the specific area of ontology-based recommendation for e-learning. In this paper, we present a review of literature on ontology-based recommenders for e-learning. First, we analyze and classify the journal papers that were published from 2005 to 2014 in the field of ontology-based recommendation for e-learning. Secondly, we categorize the different recommendation techniques used by ontology-based e-learning recommenders. Thirdly, we categorize the knowledge representation technique, ontology type and ontology representation language used by ontology-based recommender systems, as well as types of learning resources recommended by e-learning recommenders. Lastly, we discuss the future trends of this recommendation approach in the context of e-learning. This study shows that use of ontology for knowledge representation in e-learning recommender systems can improve the quality of recommendations. It was also evident that hybridization of knowledge-based recommendation with other recommendation techniques can enhance the effectiveness of e-learning recommenders.     

A tourism destination recommender system using users’ sentiment and temporal dynamics

With the development and popularity of social networks, an increasing number of consumers prefer to order tourism products online, and like to share their experiences on social networks. Searching for tourism destinations online is a difficult task on account of its more restrictive factors. Recommender system can help these users to dispose information overload. However, such a system is affected by the issue of low recommendation accuracy and the cold-start problem. In this paper, we propose a tourism destination recommender system that employs opinion-mining technology to refine user sentiment, and make use of temporal dynamics to represent user preference and destination popularity drifting over time. These elements are then fused with the SVD+ + method by combining user sentiment and temporal influence. Compared with several well-known recommendation approaches, our method achieves improved recommendation accuracy and quality. A series of experimental evaluations, using a publicly available dataset, demonstrates that the proposed recommender system outperforms the existing recommender systems.     

The inseparability problem in interactive case-based reasoning

In applications of interactive case-based reasoning (CBR) such as help-desk support and recommender systems, a problem that often affects retrieval performance is the inability to distinguish between cases that have different solutions. For example, it is not unusual in recommender systems for two distinct products or services to have the same values for all attributes in the case library. While it is unlikely that both solutions are equally suited to the user's requirements, the system cannot help the user to choose between them. This problem, which we refer to as inseparability, can also arise as a result of incomplete data in the target problem presented for solution by a CBR system. We present an in-depth analysis of the inseparability problem, its relationship to the problem of incomplete data, and its impact on retrieval performance.     

Evaluating recommender systems from the user’s perspective: survey of the state of the art

A recommender system is a Web technology that proactively suggests items of interest to users based on their objective behavior or explicitly stated preferences. Evaluations of recommender systems (RS) have traditionally focused on the performance of algorithms. However, many researchers have recently started investigating system effectiveness and evaluation criteria from users?? perspectives. In this paper, we survey the state of the art of user experience research in RS by examining how researchers have evaluated design methods that augment RS??s ability to help users find the information or product that they truly prefer, interact with ease with the system, and form trust with RS through system transparency, control and privacy preserving mechanisms finally, we examine how these system design features influence users?? adoption of the technology. We summarize existing work concerning three crucial interaction activities between the user and the system: the initial preference elicitation process, the preference refinement process, and the presentation of the system??s recommendation results. Additionally, we will also cover recent evaluation frameworks that measure a recommender system??s overall perceptive qualities and how these qualities influence users?? behavioral intentions. The key results are summarized in a set of design guidelines that can provide useful suggestions to scholars and practitioners concerning the design and development of effective recommender systems. The survey also lays groundwork for researchers to pursue future topics that have not been covered by existing methods.     

An agent-based recommender system for developing customized families of products

Electronic markets and web-based content have improved traditional product development processes by increasing the participation of customers and applying various recommender systems to satisfy individual customer needs. Agent-based systems based on agents’ roles and tasks can provide appropriate tools to solve product design problems by recommending design knowledge and information. This paper introduces an agent-based recommender system to support designing families of products based on customers’ preferences in dynamic electronic market environments. In the proposed system, a market-based learning mechanism is applied to determine the customers’ preferences for recommending appropriate products to customers of the product family. We demonstrate the implementation of the proposed recommender system using a multi-agent framework. Through simulated experiments, we illustrate that the proposed recommender system can help determine the preference values of products for customized recommendation and market segment design in various electronic market environments.     

基于Web Mining的推荐系统

推荐系统(Recommender System)被电子商务站点用来向顾客提供信息以帮助顾客选择产品,其基本思想是以统计结果或者顾客以前的行为记录为依据,推测顾客未来可能的行为并给出相应的推荐。本文对基于传统技术和Web mining技术的推荐系统进行了简要综述,同时描述了基于Web mining技术的推荐系统的工作流程,重点分析了应用于推荐系统的各种具体Web mining技术及其算法比较。     

社会化推荐系统综述

推荐系统可以帮助网民从大量纷繁的信息中找到目标信息,能有效提高网民信息检索能力,然而推荐系统存在数据稀疏性、冷启动以及系统性能方面的问题。为解决这方面的问题,提出将社交关系应用于推荐系统,该方法是提高推荐准确性的一个重要途径,在多年的科研实践中取得了重要进展,因此该研究方向也日益成为众多学者关注的领域,有关这方面的研究也越来越活跃。通过对社会化推荐系统概念进行梳理,对社会化推荐系统与传统推荐系统进行比较,回顾总结了社会化推荐系统的研究现状,希望能从研究现状中找出新规律,寻求新的突破点,并对社会化推荐系统的发展趋势进行展望,以期对后来研究者有所帮助。     

E-Commerce Recommendation Applications

Recommender systems are being used by an ever-increasing number of E-commerce sites to help consumers find products to purchase. What started as a novelty has turned into a serious business tool. Recommender systems use product knowledge—either hand-coded knowledge provided by experts or mined knowledge learned from the behavior of consumers—to guide consumers through the often-overwhelming task of locating products they will like. In this article we present an explanation of how recommender systems are related to some traditional database analysis techniques. We examine how recommender systems help E-commerce sites increase sales and analyze the recommender systems at six market-leading sites. Based on these examples, we create a taxonomy of recommender systems, including the inputs required from the consumers, the additional knowledge required from the database, the ways the recommendations are presented to consumers, the technologies used to create the recommendations, and the level of personalization of the recommendations. We identify five commonly used E-commerce recommender application models, describe several open research problems in the field of recommender systems, and examine privacy implications of recommender systems technology.     

A generalized taxonomy of explanations styles for traditional and social recommender systems

Recommender systems usually provide explanations of their recommendations to better help users to choose products, activities or even friends. Up until now, the type of an explanation style was considered in accordance to the recommender system that employed it. This relation was one-to-one, meaning that for each different recommender systems category, there was a different explanation style category. However, this kind of one-to-one correspondence can be considered as over-simplistic and non generalizable. In contrast, we consider three fundamental resources that can be used in an explanation: users, items and features and any combination of them. In this survey, we define (i) the Human style of explanation, which provides explanations based on similar users, (ii) the Item style of explanation, which is based on choices made by a user on similar items and (iii) the Feature style of explanation, which explains the recommendation based on item features rated by the user beforehand. By using any combination of the aforementioned styles we can also define the Hybrid style of explanation. We demonstrate how these styles are put into practice, by presenting recommender systems that employ them. Moreover, since there is inadequate research in the impact of social web in contemporary recommender systems and their explanation styles, we study new emerged social recommender systems i.e. Facebook Connect explanations (HuffPo, Netflix, etc.) and geo-social explanations that combine geographical with social data (Gowalla, Facebook Places, etc.). Finally, we summarize the results of three different user studies, to support that Hybrid is the most effective explanation style, since it incorporates all other styles.     

A novel social network hybrid recommender system based on hypergraph topologic structure

With the advent and popularity of social network, more and more people like to share their experience in social network. However, network information is growing exponentially which leads to information overload. Recommender system is an effective way to solve this problem. The current research on recommender systems is mainly focused on research models and algorithms in social networks, and the social networks structure of recommender systems has not been analyzed thoroughly and the so-called cold start problem has not been resolved effectively. We in this paper propose a novel hybrid recommender system called Hybrid Matrix Factorization(HMF) model which uses hypergraph topology to describe and analyze the interior relation of social network in the system. More factors including contextual information, user feature, item feature and similarity of users ratings are all taken into account based on matrix factorization method. Extensive experimental evaluation on publicly available datasets demonstrate that the proposed hybrid recommender system outperforms the existing recommender systems in tackling cold start problem and dealing with sparse rating datasets. Our system also enjoys improved recommendation accuracy compared with several major existing recommendation approaches.     

Progress in context-aware recommender systems — An overview

Recommender Systems are the set of tools and techniques to provide useful recommendations and suggestions to the users to help them in the decision-making process for choosing the right products or services. The recommender systems tailored to leverage contextual information (such as location, time, companion or such) in the recommendation process are called context-aware recommender systems. This paper presents a review on the continual development of context-aware recommender systems by analyzing different kinds of contexts without limiting to any specific application domain. First, an in-depth analysis is conducted on different recommendation algorithms used in context-aware recommender systems. Then this information is used to find out that how these techniques deals with the curse of dimensionality, which is an inherent issue in such systems. Since contexts are primarily based on users’ activity patterns that leads to the development of personalized recommendation services for the users. Thus, this paper also presents a review on how this contextual information is represented (either explicitly or implicitly) in the recommendation process. We also presented a list of datasets and evaluation metrics used in the setting of CARS. We tried to highlight that how algorithmic approaches used in CARS differ from those of conventional RS. In that, we presented what modification or additions are being applied on the top of conventional recommendation approaches to produce context-aware recommendations. Finally, the outstanding challenges and research opportunities are presented in front of the research community for analysis     

基于相似模式聚类的电子商务网站个性化推荐系统研究

保证个性化推荐系统产生高质量的推荐结果的重要因素是:系统必须要确定访问者在访问行为的相似程度,从而能预测访问者的访问和购买兴趣。实现此功能的关键技术是计算访问者对象在整个或者部分属性空间的相似距离,从而得到访问行为的相似程度。该文首先分析了目前在推荐系统中常用的用于计算访问行为相似程度的距离函数,发现它们是测定访问者对象在所有测试属性空间上的平均测定,而在属性集的子维空间上的相似模式并没有有效地挖掘出来。然后提出一种新的基于相似模式聚类算法的电子商务个性化推荐系统,综合考虑可供挖掘的数据源(如:网站内容,网站的超链接结构,顾客访问网站的行为,以及商业的实际购买情况,顾客的身份数据等)获取用户访问电子商务网站的访问页面序列,构建较高购买者的顾客行为的矩阵模型,高效地得到访问者对象在整个或者部分属性空间的相似访问行为,然后通过挖掘潜在购买者与较高购买者的相似模式特征,帮助顾客发现他所希望购买的产品信息,用于提高实际购买量,实验数据表明,该系统高效并可广泛使用。     

Estimating time and score uncertainty in generating successful learning paths under time constraints

This paper addresses the problem of course (path) generation when a learner's available time is not enough to follow the complete course. We propose a method to recommend successful paths regarding a learner's available time and his/her knowledge background. Our recommender is an instance of long term goal recommender systems (LTRS). This method, after locating a target learner in a course graph, applies a depth‐first search algorithm to find all paths for the learner given a time limitation. In addition, our method estimates learning time and score for all paths. It also indicates the probability of error for the estimated time and score for each path. Finally, our method recommends a path that satisfies the learner's time restriction while maximizing expected learning score. In order to evaluate our proposals for time and score estimation, we used the mean absolute error and average MAE. We have evaluated time and score estimation methods, including one proposed in the literature, on two E‐learning datasets.     

VCR: Virtual community recommender using the technology acceptance model and the user’s needs type

A recommender system is a kind of automated and sophisticated decision support system that is needed to provide a personalized solution in a brief form without going through a complicated search process. There have been a substantial number of studies to make recommender systems more accurate and efficient, however, most of them have a common critical limitation – these systems are used as virtual salespeople, rather than as marketing tools. A crucial reason for this phenomenon is that the models suggested by prior studies only focus on a user’s behavioral outcomes without consideration of the embedded procedure. In this study, we propose a novel recommender system based on user’s behavioral model. Our proposed system, labeled VCR—virtual community recommender, recommends optimal virtual communities for an active user by case-based reasoning (CBR) using behavioral factors suggested in the technology acceptance model (TAM) and its extended models. In addition, it refines its recommendation results by considering the user’s needs type at the point of usage. To test the usefulness of our recommendation model, we conducted two-step validation–empirical validation for the collected data set, and practical validation to investigate the actual satisfaction level of users. Experimental results showed that our model outperformed all comparative models from the perspective of user satisfaction.     

Preventing Recommendation Attack in Trust-Based Recommender Systems

Despite its success, similarity-based collaborative filtering suffers from some limitations, such as scalability, sparsity and recommendation attack. Prior work has shown incorporating trust mechanism into traditional collaborative filtering recommender systems can improve these limitations. We argue that trust-based recommender systems are facing novel recommendation attack which is different from the profile injection attacks in traditional recommender system. To the best of our knowledge, there has not any prior study on recommendation attack in a trust-based recommender system. We analyze the attack problem, and find that “victim” nodes play a significant role in the attack. Furthermore, we propose a data provenance method to trace malicious users and identify the “victim” nodes as distrust users of recommender system. Feasibility study of the defend method is done with the dataset crawled from Epinions website.     

基于领域最近邻的协同过滤推荐算法

协同过滤是目前电子商务推荐系统中广泛应用的最成功的推荐技术,但面临严峻的用户评分数据稀疏性和推荐实时性挑战. 针对上述问题,提出了基于领域最近邻的协同过滤推荐算法,以用户评分项并集作为用户相似性计算基础,将并集中的非目标用户区分为无推荐能力和有推荐能力两种类型;对于前一类用户不再计算用户相似性以改善推荐实时性,对于后一类用户则提出“领域最近邻”方法对并集中的未评分项进行评分预测,从而降低数据稀疏性和提高最近邻寻找准确性. 实验结果表明,该算法能有效提高推荐质量.