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Customers of a webshop are often presented large assortments, which can lead to customers struggling finding their desired product(s), an issue known as choice overload. In order to overcome this issue, recommender systems are used in webshops to provide personalized product recommendations to customers. Though, model-based recommender systems are not able to provide recommendations to new customers (i.e., cold users). To facilitate recommendations to cold users we investigate multiple active learning strategies, and subsequently evaluate which active learning strategy is able to optimally elicit the preferences from the cold users in a matrix factorization context. Our model is empirically validated using a dataset from the webshop of de Bijenkorf, a Dutch department store. We find that the overall best-performing active learning strategy is PopError, an active learning strategy that measures the variance score for each item. [ABSTRACT FROM AUTHOR]

Recommender systems have been widely used in our life in recent years to facilitate our life. And it is very important and meaningful to improve recommendation performance. Generally, recommendation methods use users' historical ratings on items to predict ratings on their unrated items to make recommendations. However, with the increase of the number of users and items, the degree of data sparsity increases, and the quality of recommendations decreases sharply. In order to solve the sparsity problem, other auxiliary information is combined to mine users' preferences for higher recommendation quality. Similar to rating data, review data also contain rich information about users' preferences on items. This paper proposes a novel recommendation model, which harnesses an adversarial learning among auto-encoders to improve recommendation quality by minimizing the gap of the rating and review relation between a user and an item. The empirical studies on real-world datasets show that the proposed method improves the recommendation performance. [ABSTRACT FROM AUTHOR]

The Internet of Things (smart things) is used in many sectors and applications due to recent technological advances. One of such application is in the transportation system, which is of primary use for the users to move from one place to another place. The smart devices which were embedded in vehicles are useful for the passengers to solve his/her query, wherein future vehicles will be fully automated to the advanced stage, i.e. future cars with driverless feature. These autonomous cars will help people a lot to reduce their time and increases their productivity in their respective (associated) business. In today's generation and in the near future, privacy preserving and trust will be a major concern among users and autonomous vehicles and hence, this paper will be able to provide clarity for the same. Many attempts in previous decade have provided many efficient mechanisms, but they all work only with vehicles along with a driver. However, these mechanisms are not valid and useful for future vehicles. In this paper, we will use deep learning techniques for building trust using recommender systems and Blockchain technology for privacy preserving. We also maintain a certain level of trust via maintaining the highest level of privacy among users living in a particular environment. In this research, we developed a framework that could offer maximum trust or reliable communication to users over the road network. With this, we also preserve privacy of users during traveling, i.e., without revealing identity of respective users from Trusted Third Parties or even Location Based Service in reaching a destination. Thus, Deep Learning based Blockchain Solution (DLBS) is illustrated for providing an efficient recommendation system. [ABSTRACT FROM AUTHOR]

A recommender system (RS) delivers personalized suggestions on products based on the interest of a particular user. Content-based filtering (CBF) and collaborative filtering (CF) schemes have been previously used for this task. However, the main challenge in RS is cold start problem (CSP). This originates once a new user joins the system which makes the recommendation task tedious due to the shortage of information (clickstream, dwell time, rating, etc.) regarding the user's interest. Therefore, CBF and CF are combined together by developing a knowledge-based preference learning (KBPL) system. This system considers the demographic data that includes gender, occupation, and age for the recommendation task. Initially, the dataset is clustered using the self-organizing map (SOM) technique, then the high dimensional data is decomposed by higher-order singular value decomposition (HOSVD) and finally, Adaptive neuro-fuzzy inference system (ANFIS) predicts the output. For the big dataset, SOM is a robust clustering method and the similarities among the users can be easily observed by grid clustering. The HOSVD extracts the required information from the available data set to find the user similarity by decomposing the dataset in lower dimensions. ANFIS uses IF-THEN rules to recommend similar product to the new users. The proposed KBPL system is evaluated with the Black Friday dataset and the obtained error value is compared with the existing CF and CBF techniques. The proposed KBPL system has obtained root mean squared error (RMSE) of 0.71%, mean absolute error (MAE) of 0.54%, and mean absolute percentage error (MAPE) of 37%. Overall, the outcome of the comparative analysis shows minimum error and better performance in terms of precision, recall, and f-measure for the proposed KBPL system compared to the existing techniques and therefore more suitable for accurately recommending the products for the new users. [ABSTRACT FROM AUTHOR]

In the current era of big data, the recommender system aspires to provide users with a tailored set of personalized items from a pool of a large population. The most popular collaborative filtering system performs this information filtering process by computing similarity among users or items. This paper proposes a similarity metric that comprises of weights and values. Values are calculated by considering the matching set of users for which similarity is to be computed. The optimal values of weights are decided using an upgraded form of the Crow Search Algorithm (CSA). The exploration and exploitation stability of CSA is improvised by making use of Levy flight diffusion, adaptive operator adjustment, and event factor. The performance of the implemented metaheuristic approach is validated on Jester, MovieLens 100K, and MovieLens 1M dataset. Comparative analysis of proposed model against several other traditional metaheuristic based personalization systems reveal that our model is less delicate to the dimension of datasets and it also presents exceptional refinement in terms of prediction complexity and accuracy. [ABSTRACT FROM AUTHOR]

Modeling the music mood has wide applications in music categorization, retrieval, and recommendation systems; however, it is challenging to computationally model the affective content of music due to its subjective nature. In this work, a structured regression framework is proposed to model the valence and arousal mood dimensions of music using a single regression model at a linear computational cost. To tackle the subjectivity phenomena, a confidence-interval based estimated consensus is computed by modeling the behavior of various annotators (e.g. biased, adversarial) and is shown to perform better than using the average annotation values. For a compact feature representation of music clips, variational Bayesian inference is used to learn the Gaussian mixture model representation of acoustic features and chord-related features are used to improve the valence estimation by probing the chord progressions between chroma frames. The dimensionality of features is further reduced using an adaptive version of kernel PCA. Using an efficient implementation of twin Gaussian process for structured regression, the proposed work achieves a significant improvement in R2 for arousal and valence dimensions relative to state-of-the-art techniques on two benchmark datasets for music mood estimation. [ABSTRACT FROM AUTHOR]

This paper proposes a new content recommendation system which combines the newly proposed embedded feature selection method and the new Fuzzy Temporal Logic based Decision Tree incorporated Convolutional Neural Network classifier. The newly proposed embedded feature selection called Fuzzy Decision Tree and Weighted Gini-Index based Feature Selection Algorithm (FDTWGI-FSA) that contains the existing incorporated the Fuzzy Decision Tree (FDT) and the Weighted Gini-index based Feature Selection Algorithm (WGIFSA) for getting optimized feature subset. Moreover, an enhanced CNN and Fuzzy Temporal Decision Tree for performing the deep learning process which is able to identify the exact e-content from the huge volume of data with the help of the recommended features by the proposed embedded feature selection method. The exact e-content can be identified after performing the five-layer network structure for extracting the relevant features and it also can be classified by applying the Fuzzy Temporal Decision Tree for the e-learners. Finally, the proposed content recommendation system provides exact content to the e-learners according to their level of understanding and it also satisfies them by providing the exact high level contents. The experiments have been conducted for evaluating the proposed content recommendation system and compared with the existing classifier including the standard CNN. [ABSTRACT FROM AUTHOR]

In Machine Learning scenarios, privacy is a crucial concern when models have to be trained with private data coming from users of a service, such as a recommender system, a location-based mobile service, a mobile phone text messaging service providing next word prediction, or a face image classification system. The main issue is that, often, data are collected, transferred, and processed by third parties. These transactions violate new regulations, such as GDPR. Furthermore, users usually are not willing to share private data such as their visited locations, the text messages they wrote, or the photo they took with a third party. On the other hand, users appreciate services that work based on their behaviors and preferences. In order to address these issues, Federated Learning (FL) has been recently proposed as a means to build ML models based on private datasets distributed over a large number of clients, while preventing data leakage. A federation of users is asked to train a same global model on their private data, while a central coordinating server receives locally computed updates by clients and aggregate them to obtain a better global model, without the need to use clients' actual data. In this work, we extend the FL approach by pushing forward the state-of-the-art approaches in the aggregation step of FL, which we deem crucial for building a high-quality global model. Specifically, we propose an approach that takes into account a suite of client-specific criteria that constitute the basis for assigning a score to each client based on a priority of criteria defined by the service provider. Extensive experiments on two publicly available datasets indicate the merits of the proposed approach compared to standard FL baseline. [ABSTRACT FROM AUTHOR]

People spend their leisure time on cultural and historical stories by visiting exhibitions and museums with family members and friends. This small gathering establishes a voluntary platform to engage in activities and share experiential knowledge. Since members of a small group tend to have diverse preferences, both individual and group preferences should be considered for a cohesive and harmonious guide. This paper proposes a mixed-initiative tour path planning system for multiple visitors that builds a group path supported by automatic path generation and users' participation. In the proposed system, individual user profiles are merged into a group profile by favoring multiple users' higher preferences with low deviation. Then the system constructs a tour path based on mixed-initiative interaction that consists of the system's automatic decision and participation of members. When group members have similar preferences, a tour path is automatically decided by the system. If group members have different and divergent preferences, the system asks group members to intervene and confirm appropriate places to collaboratively construct a tour path. To show feasibility of our proposed system, we evaluate our approach in twofold consists of a synthesized group simulation and a user study. For the simulation, we collected user preferences of 12 real users to simulate groups of two, three, and four members and explored characteristics of similar and different preference scenarios. For the user study, we conducted a comparative study with 11 participants under 4 different exhibition scenarios using the implemented mixed-initiative path planning system. Evaluation results support that our system constructs a cohesive, satisfying and usable path for a small group tour. [ABSTRACT FROM AUTHOR]

If the online education platform simply presents offline course content and teaching resources, it will result in poor interaction between teachers and students and poor student learning efficiency because of the time and space barriers in distance education. At the same time, it has a one-way teaching for all students without any difference, so its personalization is poor. In order to improve the efficiency of network education knowledge recommendation, based on the traditional neural network, this study combines the actual needs of network education to construct an improved neural network-path sorting algorithm. Moreover, this study builds a network education knowledge recommendation system based on the algorithm and explores the functions of each module of the system to realize all system functions. In addition, this study performs system function tests on a complete system. The results show that the proposed algorithm is higher than the traditional recommendation algorithm in recommendation effect and recommendation efficiency, and has certain practical effects, and can provide theoretical reference for subsequent related research. [ABSTRACT FROM AUTHOR]

Group recommender system provides suggestions for a group of users by exploring the choices of individual users of the group. Popularity of group recommender systems is increasing because many activities such as listening to music, watching movies, traveling, etc. are normally performed in groups rather individually. Group recommender systems like personal recommender systems also suffer from cold start and sparsity issues. The cold start and sparsity issues result into inaccurate recommendation computation which degrades the recommendation quality. To handle the cold start and sparsity issues in a Group Recommender System (GRS), this paper proposes to use cross domain approach and introduces Cross Domain Group Recommender System (CDGRS). The recommendations provided by trustworthy and reputed users in the group enhance the acceptance towards the presented recommendations as compared to the other individuals in the group. We have combined the social factors e.g. trust and reputation to get influential user in the group recommendation. A prototype of the system is developed for tourism domain that incorporates four sub-domains i.e. restaurants, hotels, tourist places and shopping places. The performance of CDGRS is compared with GRS. Spearman's Correlation Coefficient, MAE, RMSE, Precision, Recall and F-measure are used to find the accuracy of the generated recommendations. [ABSTRACT FROM AUTHOR]

Recommender systems promote sales of products and services by helping users alleviate the information overload problem. Collaborative filtering is most extensively used approach to design recommender system. The main idea of collaborative filtering is that recommendation for each active user is received by comparing with the preferences of other users who have rated the product in similar way to the active user. Matrix factorization technique is one of the most widely employed collaborative filtering techniques due to its effectiveness and efficiency in dealing with very large user-item rating matrices. One of the principal disadvantages and challenges of the collaborative filtering type algorithms is content awareness, namely, they use only people's behavior to produce recommendations and are not aware of the predicted content's metadata. In this work, we study and compare two ways of incorporating this type of content information directly into the matrix factorization approach. We extend the baseline optimization problem by two techniques. The first one penalizes item and user feature vectors with some small amounts pushing them towards each other in the latent space, and the second one makes two item and user specific latent feature vectors as similar as possible if the two items and users have similar tagging history. The results of the experiments, on the benchmark data sets, show that the proposed model has a better performance compared to some other methods. [ABSTRACT FROM AUTHOR]

Meteorological hazards have great influence all over the world. An emergency plan is an important means of coping with meteorological hazards. The preparation of emergency plans needs to refer to historical emergency plans, but these are too numerous and are of uneven quality. We can alleviate these problems by means of recommender systems, which are very useful tools in many domains; however, they suffer from information overload. In this paper, we propose a Semantic-Aware Collaborative Filtering method, which is called SACF, for emergency plans recommendation to address the aforementioned challenges. It is designed to effectively present a highly targeted emergency plan recommendation list and recommend the most appropriate emergency plans for a targeted meteorological hazards event. Specifically, we use semantic knowledge to represent scenario-based meteorological hazards, including target and previous events. The search for similar events (i.e., neighbors) for a collaborative filtering recommendation algorithm is adopted. By helping to avoid both the generation of fake neighbors and also the omission of true neighbors the recommendation process is improved. Finally, extensive experiments are conducted on a real-world dataset, and the results demonstrate that SACF improves the accuracy of emergency plan recommendations. [ABSTRACT FROM AUTHOR]

Preference representation and reasoning play a central role in supporting users with complex and multi-factorial decision processes. In fact, user tastes can be used to filter information and data in a personalized way, thus maximizing their expected utility. Over the years, many frameworks and languages have been proposed to deal with user preferences. Among them, one of the most prominent formalism to represent and reason with (qualitative) conditional preferences (CPs) are conditional preference theories (CP-theories). In this paper, we show how to combine them with Semantic Web technologies in order to encode in a standard SPARQL 1.1 query the semantics of a set of CP statements representing user preferences by means of RDF triples that refer to a "preference" OWL ontology. In particular, here we focus on context-uniform conditional (cuc) acyclic CP-theories [Artif. Intell. 1752011, 1053–1091]. The framework that we propose allows a standard SPARQL client to query Linked Data datasets, and to order the results of such queries relative to a set of user preferences. [ABSTRACT FROM AUTHOR]

Recommender Systems (RS) are expected to suggest the accurate goods to the consumers. Cold start is the most important challenge for RSs. Recent hybrid RSs combine ConF and ColF. We introduce an ontological hybrid RS where the ontology has been employed in its ConF part while improving the ontology structure by its ColF part. In this paper, a new hybrid approach is proposed based on the combination of demographic similarity and cosine similarity between users in order to solve the cold start problem of new user type. Also, a new approach is proposed based on the combination of ontological similarity and cosine similarity between items in order to solve the cold start problem of new item type. The main idea of the proposed method is to expand user/item profiles based on different strategies to build higher-performing profiles for users/items. The proposed method has been evaluated on a real dataset and the experimentations indicate the proposed method has the better performance comparing with the state of the art RS methods, especially in the case of the cold start. [ABSTRACT FROM AUTHOR]

With the popularity of networks and the increasing number of online users, recommender systems have suffered from the privacy leakage of sensitive information. While people enjoy recommender services, their information is exposed to the networks. To protect the privacy of users when using the recommender services, we propose a multi-level combined privacy-preserving model that maintains high accuracy of recommendation with privacy protection and alleviates the data sparsity problem. Our scheme contains two steps of recommendation. First, a multi-level combined random perturbation (MCRP) model is proposed on the client side. Our model dynamically divides multiple disturbance levels and adds noise of different ranges to the rating matrix according to Gaussian and uniform mixed disturbances. Second, on the server side, we propose a pseudo rating prediction filling (PRPF) algorithm based on the matrix factorization model. Combining the PRPF algorithm with the MCRP method significantly improves the recommender accuracy and effectively increases privacy security. Sensitive analysis and comparison experiments show that the proposed privacy method has certain advantages in security and recommender accuracy by using three publicly available datasets. [ABSTRACT FROM AUTHOR]

A fuzzy system is a system that defines input, output, and state variables on a fuzzy set and is a generalization of a deterministic system. The fuzzy system begins at the macro level and covers the fuzzy features of human brain thinking. It has advantages in describing advanced knowledge. Fuzzy sets can mimic the comprehensive conclusions of people solving fuzzy information problems, which are difficult to solve by conventional mathematical methods, so computer applications can be extended to humanities, social sciences and complex systems. In this way, it can better solve nonlinear problems and is widely used in automatic control, decision analysis, time series signal processing, economic information systems, medical diagnostic systems, and earthquake prediction systems. This paper aims to study the data mining algorithm of fuzzy systems based on fuzzy sets. By using the powerful fuzzy data modeling function of fuzzy theory, it combines with other intelligent processing methods, and makes practical use in industrial life. By comparing the application of fuzzy set data mining and algorithm, it is found that in the application state, the economic benefits of the factory are improved by 36% and the production efficiency is improved by 25% under the application of data mining and algorithm. The research data shows that the data mining and recommendation algorithms of fuzzy sets are beneficial to the development and operation of the factory. The research results show that compared with the conventional production and processing plan, the technology uses fuzzy set theory to transform the fuzzy attributes, which is more advantageous in scientific and technical systems and algorithms with its scientificity, accuracy, innovation and extensiveness. [ABSTRACT FROM AUTHOR]

Recommender System has become one of the most effective tools for provisioning user-interest based decision-making services. With its capability to generate efficient recommendations, users are directed towards items that are optimal with compliance to their needs, and preferences. Inspired from these aspects, this paper presents a novel recommendation technique based on context-specific information and social network analysis for determining dependable items. Context specific information provides a quantifiable measure of user interest for dependability whereas social network analysis determines the degree of similarity among other users. Both types of information are acquired and analyzed in the form of linguistic terms. This fuzzy-based quantification provides an effective way to evaluate social-ratings and social-similarity. For validation, it is evaluated in the on-line mobile purchase scenario. Based on the numerous simulations performed on different data sets, performance estimators in the form of Temporal Delay, Statistical Analysis and System Stability are estimated. It is concluded that the proposed mechanism of recommendation is effective and efficient in comparison to state-of-the-art recommender systems. [ABSTRACT FROM AUTHOR]

Recommender systems are widely used to provide users with items they may be interested in without explicitly searching. However, they suffer from low accuracy and scalability problems. Although existing clustering techniques have been incorporated to solve these inherent problems, most of them fail to achieve further improvement in recommendation accuracy because of ignoring the correlations between items and the different effects of item attributes on recommendation results. In this article, we propose a novel recommendation algorithm to alleviate these issues to a large extent. First of all, users and items are clustered into multiple cluster subsets based on user-item rating matrix and item attribute deriving from domain experts, respectively. Then we use a selection method relying on item attribute to mine candidate items and only their predictions will be calculated in the next step, which can save the computation time greatly. Furthermore, by weighting the predictions with TF-IDF (Term Frequency-Inverse Document Frequency) weights, the top-N recommendations are generated to the target user for return. Finally, comparative experiments on two real datasets demonstrate that this algorithm provides superior recommendation accuracy in terms of MAE (Mean Absolute Error) and RMSE (Root Mean Square Error). [ABSTRACT FROM AUTHOR]

In the last decades, individual urban traffic flows have increased all over the world with a consequent growth of road congestion and environmental pollution. In this context, car-pooling is an interesting car-based alternative to satisfy the individual mobility demand by optimizing the car loading factor with respect to the number of passengers, provided that all the participants share trip origin and destination in the same time slot. To make the system more appealing, this paper proposes an on-demand car-pooling service adopting variable fares, on the basis of trip length and number of participants. Multi-agent, reputation and recommender system technologies in synergy with a routing algorithm have been used to this aim. Experiments on simulated data proved the potentiality of the proposed approach. [ABSTRACT FROM AUTHOR]

When a person visits an unknown large city having multiple interesting locations, it is not so easy for him to find one location that is lively and convenient to visit in a given time-frame. To overcome such a problem, this paper proposes to make use of two technologies: smartphones, equipped with sensors for reading GPS coordinates; and multi-agent systems, providing assistance to users and gathering collective knowledge. Data collected by means of devices are analysed and organised in such a way to find locations that could be of immediate interest to people. Proposed agents gather opinions from several users, in terms of scores quantifying the level of satisfaction on visiting some place on a given time-frame. While gathering such an opinion, a solution is put into place to preserve user privacy (his location). Suggestions are made to potentially interested users by selecting for them locations according to closeness and satisfaction scores. In this approach, interesting locations emerge from the analysis of data gathered, hence scores and suggestions can be available for any large city in any place, provided that enough people hand data to the system. Moreover, such places are found dynamically according to people behaviour and preferences. [ABSTRACT FROM AUTHOR]

High Utility Itemset Mining (HUIM) is playing an important role in extracting meaningful knowledge that is profitable itemsets rather than their occurrence frequency. HUIM result thrives into a huge number of utility itemsets that makes it difficult in decision policy. The alternative procedure is condensed representation of HUI's that contains utility itemsets without any redundancy. Closed High Utility Itemsets (CHUI) and High Utility Generators (HUG) are lossless utility itemsets useful in recommendation systems. In this paper, we address how to extract Closed and Generator HUI's from the given dataset. For faster accessing, it is proposed hash based technique that store itemsets with the frequency, utility value, closed flag, and generator flag. Experimental results shows that it outperforms other approaches in time and space. [ABSTRACT FROM AUTHOR]

In the last decades, individual urban traffic flows have increased all over the world with a consequent growth of road congestion and environmental pollution. In this context, car-pooling is an interesting car-based alternative to satisfy the individual mobility demand by optimizing the car loading factor with respect to the number of passengers, provided that all the participants share trip origin and destination in the same time slot. To make the system more appealing, this paper proposes an on-demand car-pooling service adopting variable fares, on the basis of trip length and number of participants. Multi-agent, reputation and recommender system technologies in synergy with a routing algorithm have been used to this aim. Experiments on simulated data proved the potentiality of the proposed approach. [ABSTRACT FROM AUTHOR]

Recommender systems are decision support systems that play an important part in generating a list of product or service recommendations for users based on the past experiences and interactions. The most popular recommendation method is Collaborative Filtering (CF) that is based on the users' rating history to generate the recommendation. Although, recommender systems have been applied successfully in different areas such as e-Commerce and Social Networks, the popularity bias is still one of the challenges that needs to be further researched. Therefore, we propose a multi-level method that is based on a switching approach which solves the long tail recommendation problem (LTRP) when CF fails to find the target case. We have evaluated our method using two public datasets and the results show that it outperforms a number of bases lines and state-of-the-art alternatives with a further reduce of the recommendation error rates for items found in the long tail. [ABSTRACT FROM AUTHOR]

Collaborative filtering (CF), one of the most famous methods for building recommendation systems, recommends relevant items to users or predicting ratings of users' unknown items. Matrix factorization (MF) models are well-known model to deal with predicting the rating problem. However, the recommendation system based on matrix factorization is hard to keep up with the rapidly changing real-world data. When ratings on new users or new items come, the static model can not fit well on new data. As a consequence, if the current thing does not apply, the prediction accuracy will lose. In addition, it is a significant computation cost to rebuild the model on the whole data. To capture these changes, in this paper, we construct an online-and-offline Collaborative Filtering with a multi-method model to improve the traditional CF method, called Online SGD with Offline Knowledge (OSGDO for short). Besides, we propose a real-time incremental recommendation framework on Apache Flink, which is a scalable stream and batch data processing platform. Meanwhile, we implement our proposed method on our proposed framework. Our method proves to be good at online training when new observations arrive. And the results of experiments show that the dynamic training process we proposed is more efficient than rebuild the model on all the data. At the same time, our algorithm performs well in practice and can achieve impressive accuracy quickly when it is tested with the well-known data sets of MoviesLens and Netflix. [ABSTRACT FROM AUTHOR]

Knowledge Graphs (KGs) have become useful sources of structured data for information retrieval and data analytics tasks. Enabling complex analytics, however, requires entities in KGs to be represented in a way that is suitable for Machine Learning tasks. Several approaches have been recently proposed for obtaining vector representations of KGs based on identifying and extracting relevant graph substructures using both uniform and biased random walks. However, such approaches lead to representations comprising mostly popular, instead of relevant, entities in the KG. In KGs, in which different types of entities often exist (such as in Linked Open Data), a given target entity may have its own distinct set of most relevant nodes and edges. We propose specificity as an accurate measure of identifying most relevant, entity-specific, nodes and edges. We develop a scalable method based on bidirectional random walks to compute specificity. Our experimental evaluation results show that specificity-based biased random walks extract more meaningful (in terms of size and relevance) substructures compared to the state-of-the-art and the graph embedding learned from the extracted substructures perform well against existing methods in common data mining tasks. [ABSTRACT FROM AUTHOR]

Current retrieval and recommendation approaches rely on hard-wired data models. This hinders personalized customizations to meet information needs of users in a more flexible manner. Therefore, the paper investigates how similarity-based retrieval strategies can be combined with graph queries to enable users or system providers to explore repositories in the Linked Open Data (LOD) cloud more thoroughly. For this purpose, we developed novel content-based recommendation approaches. They rely on concept annotations of Simple Knowledge Organization System (SKOS) vocabularies and a SPARQL-based query language that facilitates advanced and personalized requests for openly available knowledge graphs. We have comprehensively evaluated the novel search strategies in several test cases and example application domains (i.e., travel search and multimedia retrieval). The results of the web-based online experiments showed that our approaches increase the recall and diversity of recommendations or at least provide a competitive alternative strategy of resource access when conventional methods do not provide helpful suggestions. The findings may be of use for Linked Data-enabled recommender systems (LDRS) as well as for semantic search engines that can consume LOD resources. [ABSTRACT FROM AUTHOR]

How to recommend learning resources to users accurately to meet the individual needs of users becomes the key issue with the increasing number of online education users. A personalized recommendation system was proposed in this paper based on user preference behavior data analysis to analyze the online education recommendation model. It determines the criteria set of the recommendation system with the product attribute mining method, and then uses the personalized recommendation algorithm for user preference modeling to explore the user's preference for each criterion, thereby producing more accurate recommendations. The simulation results of the algorithm proposed in this paper show that the multi-criteria recommendation algorithm using user distance similarity works best. Using this personalized recommendation algorithm based on user preference can effectively improve the recommendation quality. [ABSTRACT FROM AUTHOR]

Recommender systems have been very important components to prevent people from dwelling in the overwhelming information. In this paper we analyze the difference between item-based recommendation algorithms and SVR-based collaborative filtering algorithms, and it can be found that item-based method performs much better while the data is not sparse significantly, and SVR-based method performs better while the data is dense and small. On this premise we propose a method that can combine the advantages of these two methods by predicting a small part of ratings using SVR method firstly and then predicting the rest of ratings using the item-based algorithm, which can solve the problem of data sparsity to certain extend. Finally, we evaluate our results compared with the benchmark on different datasets and prove our method's advantages. [ABSTRACT FROM AUTHOR]

This paper presents an application of sentiment analysis on customer feedback data in the area of heavy equipment repair services. Sentiment analysis is used as a part of a framework for text mining-based Customer Loyalty Improvement Recommender System (CLIRS). In order to provide business users of the system with accurate predictions for customer satisfaction metrics, the original algorithm for the opinion mining needed to be improved. The paper presents the background of the proposed approach, the current techniques used to mine text data and existing applications of sentiment analysis. We propose an aspect-based, taxonomy-driven approach for customized sentiment analysis. The contribution of this paper is the implementation and evaluation of the proposed methods that improve the accuracy and coverage of the opinion mining algorithm. The improvements are illustrated with examples covered by the algorithm in the customer dataset. The application of the proposed methods resulted in increasing the algorithm's accuracy from 92% to 96%, and coverage from 36% to 48%. This research is an attempt to handle well-known issues in natural language processing that are currently not handled by text mining algorithms, such as ambiguity and context, opinionated verbs/nouns, subject recognition from pronouns. This is significant because the proposed techniques are generalizable to any application that uses sentiment analysis algorithm. [ABSTRACT FROM AUTHOR]

The ultimate goal of recommender systems is to suggest appealing items that users are interested in. Traditional recommender systems are built based on a general consensus that users' preferences reflect their underlying interests. Therefore, various collaborative filtering techniques have been proposed to discover items that best match users' preferences through estimating ratings for items accurately. However, determining the interestingness of items based on user preferences alone is not sufficient. In human psychology, researchers have found an important intrinsic motivation, i.e., curiosity, for seeking interestingness in social context. Instead of focusing on users' preferences, curiosity highlights the impact of the unknown and unexpectedness on a person's feeling of interestingness. In light of this, we propose a novel recommendation model which recommends items by taking consideration of the target users' curiosity in addition to their personal preferences. To model user curiosity, we adopt a psychologically inspired approach and transpose Berlyne's theory of curiosity into a computational process. Three key curiosity-stimulating factors, including surprise, uncertainty and conflict, are modelled to estimate user's curiosity for each item. The proposed recommendation model is evaluated with two large-scale real world datasets and the experimental results highlight that the consideration of social curiosity significantly improves recommendation precision, coverage and diversity. [ABSTRACT FROM AUTHOR]

This paper presents a systematic review of research into package recommender systems (PRS). PRS recommend a combination of items rather than individual items, for example, multiple attractions to visit on a day trip to a city, trousers and a shirt to wear together, or multiple dishes to make up a meal. The review provides a framework for considering existing PRS research, and highlights the techniques used for package recommendation and the evaluation methods and metrics employed. It also raises many issues that warrant future research. [ABSTRACT FROM AUTHOR]

Collaborative filtering (CF) has achieved great performance in recommender system over past decades. CF-based methods firstly map users and items to latent factors which share the same latent space, and then use a linear function to predict user ratings on items, such as inner product or cosine distance. It only uses original latent feature, however feature interactions are usually helpful in enhancing recommendation performance. To tackle such issue, we used Factorization Machines (FM) to enhanced linear methods by incorporating the second-order feature interactions. In this paper, we propose a novel hybrid model, AutoFM, which combine Denoising Autoencoder (DAE) and FM together. AutoFM follows collaborative filtering method, it firstly uses DAE to map users and items to latent factor, then it uses FM calculating user ratings on items. To tackle the cold start problem, we also take as the input of FM user's and item's side information besides of latent factor. We conduct AutoFM on three real-world datasets, and the experiment results show that AutoFM consistently outperforms the state-of-the-art method. [ABSTRACT FROM AUTHOR]

With the development of modern property service industry, the property perceived service quality (PPSQ) evaluation data is characterized by multiple evaluation subjects, complicated data structure and large scale data. Since the traditional decision-making methods are difficult to solve the above similar problems, this paper proposes a large group decision-making (LGDM) method of generalized multi-attribute and multi-scale (MAMS) based on the linear programming technique for multidimensional analysis of preference (LINMAP). In this method, the large-scale heterogeneous data of expert preference and user evaluation is fused. The decision matrix of generalized MAMS is used to process user evaluation information. The positive ideal solution (PIS) and the attribute weights are determined by the LINMAP model. The comprehensive evaluation values are calculated and hereby the alternatives are ranked order. According to the relation between attribute weights and preset values, a mechanism for identifying invalid data is designed. This paper analyzes a set of survey data of PPSQ for the four public construction projects in the same city. The analysis results show the validity and rationality of the proposed method, and develop the property service evaluation theory. [ABSTRACT FROM AUTHOR]

For the acquisition of user behavior preference in social network, usually a data mining will be conducted on the nearest neighborhood users or latestprojects based on the user's historical behavior data, so as to find similar behaviorrelationship for quantitative analysis; it can also focus on the awareness on the user-related context information based on cognitive psychology, so as to find its internal links forthe potential mining. However, these methods ignore the intrinsic link between the browsing behavior and the preferred topics in the user link connection, resulting in the limited precision and accuracy of the preference acquisition. Inspired by the theory of complex network link prediction and the topic model, anacquisition method for users' browsing behavior preference was proposed in this paper. In the multi-dimensional network link environment, by measuring the importance of the node via network centrality and search the social network link via setting the similarity threshold, the real-time multi-link information and the big data about users' browsing under each link were acquired, then the data were filteredand cleaned by using adjustable parameters. On this basis, according to the least squares criterion the data underwent a fusion and were used to construct a data node distribution model for user browsing behavior, then the frequent feature items of user browsing behavior preference were extracted. Based on the extracted feature terms, the variational Bayes approximation reasoning method was used to construct the preference topic model. Finally, the hierarchical VSM model representation method was used to establish the preference acquisition model of user browsing behavior, and the model was updated in real time by user feedback processing mechanism. The experimental results on the real data set showed that the link search method and the preference topic model provided by this paper are accurate and efficient. Compared with the classical cooperative filtering method and the context-awareness method, the precision, accuracy and effectiveness of the preference acquisition model provided this paper are significantly improved, and its adaptability has been significantly strengthened. [ABSTRACT FROM AUTHOR]

Recommender Systems (RSs) are provided as web 2.0 services that give support to electronic commerce. Today, social information has been used for improving the performances of RSs. One of the popular social networks is Facebook which recently developed a new reaction button. This button provides new opportunists to analyze and understand the user's emotions and behavior. This paper proposes a new social-based RS that benefits from social information to improve the performance of the collaborative filtering. This RS depends on satisfaction degree and emotions of users. Each user can rate an item to express his satisfaction degree with this item. Also, the user able to express his feelings toward this item through the Facebook reaction button. The proposed algorithm is experimentally compared to alternative techniques. The results obtained shows that the proposed algorithm outperforms these algorithms in recommendation quality by 40% and performance by 29%. [ABSTRACT FROM AUTHOR]

Linked Open Data has been recognized as a valuable source for background information in many data mining and information retrieval tasks. However, most of the existing tools require features in propositional form, i.e., a vector of nominal or numerical features associated with an instance, while Linked Open Data sources are graphs by nature. In this paper, we present RDF2Vec, an approach that uses language modeling approaches for unsupervised feature extraction from sequences of words, and adapts them to RDF graphs. We generate sequences by leveraging local information from graph sub-structures, harvested by Weisfeiler–Lehman Subtree RDF Graph Kernels and graph walks, and learn latent numerical representations of entities in RDF graphs. We evaluate our approach on three different tasks: (i) standard machine learning tasks, (ii) entity and document modeling, and (iii) content-based recommender systems. The evaluation shows that the proposed entity embeddings outperform existing techniques, and that pre-computed feature vector representations of general knowledge graphs such as DBpedia and Wikidata can be easily reused for different tasks. [ABSTRACT FROM AUTHOR]

Cyber-physical Social Network (CPSN) becomes an essential component of daily life. In recent years, CPSN has dragged millions of users to convey their social opinions. It is highly desirable to mine influential features from such diverse data to make a prediction on users' Point of Interest (POI). Notably, social ties of the user in a specific location have a tendency to share similar opinions. Thus with the appearance of social links, the location based recommendations become popular to acquire reliable POI recommendations. Collaborative Filtering Recommender System (CFRS) able to discover reliable POI recommendations for the target user based on Location-based CPSN. To enhance the performance of CFRS, a clustering ensemble model is proposed in this article. Four different swarm intelligent based cluster optimization algorithms were utilized to generate finite clusters. The experiment is conducted on two real-time social network dataset to exhibit the performance of the proposed CE-CFRS. The result shows that the clustering ensemble model outperforms a single clustering model in terms of assessment metrics. [ABSTRACT FROM AUTHOR]

Context aware recommender system has become an area of rigorous research attributing to incorporate context features, thereby increases accuracy while making recommendations. Most of the researches have proved neighborhood based collaborative filtering to be one of the most efficient mechanisms in recommender systems because of its simplicity, intuitiveness and wide usage in commercial domains. However, the basic challenges observed in this area include sparsity of data, scalability and utilization of contexts effectively. In this study, a novel framework is proposed to generate recommendations independently of the count and type of context dimensions, hence pertinent for real life recommender systems. In the framework, we have used k-prototype clustering technique to group contextually similar users to get a reduced and effective set. Additionally, particle swarm optimization technique is applied on the closest cluster to find the contribution of different context features to control data sparsity problem. Also, the proposed framework employs an improved similarity measure which considers contextual condition of the user. The results came from the series of experiments using two context enriched datasets showcasing that the proposed framework increases the accuracy of recommendations over other techniques from the same domain without consuming extra cost in terms of time. [ABSTRACT FROM AUTHOR]

Rapid web growth and associated applications have proven of colossal importance for recommender systems. In the current digital world, a recommender system aims to acquire high-level prediction-based accuracy. However, many studies have suggested diversity-based recommendations are required for high-level accuracy. Group recommendation systems (GRS) recommend lists of items to a group of users according to their social activities, such as planning for a holiday tour, watching movies, etc. Using GRS, preferences/choices shared by users affected all the available aggregation with GRS leads to information loss and negatively affects 'diversity.' To handle the problem of 'information loss,' which is caused by aggregation, this paper proposes fuzzy-based GRS and argues that communicating such hesitant information will prove beneficial to generating recommendations. To find the valuable suggestions, greater focus must be dedicated to avoiding lack of variety and interest in the complete list of recommendations. In this article, we propose a novel Parallel Computing Group Recommendation System, which quantifies different approaches, chooses the right approach for group recommendation, and quickly generates optimal results. This proposed approach is an ensemble model of parallel ranking and matrix factorization that facilitates a diversified group recommendation list. Experimental evaluation signals that our model achieves higher diversity positively packed with user satisfaction. [ABSTRACT FROM AUTHOR]

With the recent developments in digital technologies, the cultural heritage domain has attracted new researchers to drive technological trends for offering interactive and pleasant experience to users. The emergences of location-based services, recommendation systems, and the internet of things have created a smart research space to support cultural heritage visitors. In this paper, we present an intelligent cultural space through the development of proximity detection method and the deployment of smart sense bricks. The presented intelligent cultural space is supported by the CHXplorer-Information Management System to present multimedia content to the users through our CHXplorer mobile decision-support tool. The CHXplorer is designed to enhance the satisfaction and enjoyment of the user visiting the cultural heritage sites, and it is capable of generating personalized recommendations to the active target user. The effectiveness and efficiency of the presented CHXplorer are experimentally evaluated and user study made establishes the users' positive feedback on the system. [ABSTRACT FROM AUTHOR]

Increase in chronic diseases among people gives the health care industry a challenging problem. Healthcare industry is using the Internet-of-Things (IoT) to create systems that monitor patients. The ultimate task of the system is to minimize manual efforts made to recommend food and drugs for chronic patients. However, many uncertain factors are involved with chronic patients, and existing models unable to handle it efficiently often lead to poor results. Medical records gathered from diverse devices, such as mobile and IoT devices that are raw in nature or in different formats cannot be utilized for further analysis. Since patient records grow rapidly, it is difficult for health care systems to manage and control. To overcome these limitations, the proposed system develops a fuzzy ontology-based recommender system using Type-2 fuzzy logic to recommend foods and drugs for chronic (diabetic) patient. Extraction of risk factors for chronic patients is achieved via wearable sensors and IoT-based electronic medical records are linked with linked open data (LOD) to create a knowledge base. Since, patient data sets are huge; cloud services are used to store and retrieve data for further analysis. An experiment is conducted on patient datasets and the results illustrate that the proposed work is efficient for patient data enrichment, risk factor extraction and appropriate medical advice for chronic patients. [ABSTRACT FROM AUTHOR]

Personal information management enables users to manage and classify information via the social tagging. The personal information management platform has recently successfully adopted social networks, enabling users to conveniently share their preferences of information with each other. The emerging social networks generate new concepts for designing modern recommender systems in personal information management and sharing platforms. To design a recommender mechanism for the personal information management and sharing platforms, this work incorporates tag-based personalized interest and social network relationships into a modified Bayesian probability model. The proposed system is demonstrated with experimental datasets obtained from a popular social resource sharing website. The performances of the proposed system are evaluated based on the word2vec word embedding model. Experimental results indicate that incorporating social network information and personalized tag-based preference with the Bayesian model can improve the recommendation quality for social information sharing websites. [ABSTRACT FROM AUTHOR]

Context Aware Recommender Systems exploit specific situation of users for recommendations, hence are more accurate and satisfactory. Neighborhood based collaborative filtering is the most successful approach in this area owing of its simplicity, intuitiveness, efficiency and domain independence. The key of this approach is to find similarity between users or items using user–item–context rating matrix. Typically, context aware datasets are highly sparse since there are not enough or no preferences under most contextual conditions. Traditional similarity measures such as Pearson correlation coefficient, Cosine and Mean squared difference suffer from co-rated item problem and do not consider contextual conditions of the users. Therefore, these measures are not effective for sparse datasets. Therefore, the aim of this paper is to propose a new similarity measure and its variants based on Bhattacharyya Coefficient which are suitable for sparse datasets weighted by contextual similarity. Subsequently, we have applied them in neighborhood based algorithms where each component is contextually weighted. The experiments are performed on two contextually rich datasets which are especially designed to do personalization research instead traditional well known datasets. The results for Individual and Group recommendations indicate that the proposed similarity measure based algorithms have significantly increased the accuracy of predictions over traditional Pearson correlation coefficient measure based algorithms. [ABSTRACT FROM AUTHOR]

The heightening in the available information in the form of digital data and the number of users on the Internet have engendered a challenge of overburden of data which obstructs access to interested item on the Internet timely. There are many information retrieval systems which try to solve the problem of information overloading but in their cases prioritization and personalization of information were absent. The main aim is to develop a recommender system using item based collaborative filtering technique and K-means. The most popular algorithm in the recommender system's field is the collaborative filtering technique. Recommender systems are the filtering systems for information that concerned with the problem of information overburden by filtering essential information fragment out of enormous dynamically promoted information according to person's attentiveness, taste and distinguished behavior about them. We are considering m users, n items (in numbers) and presenting a model to fabricate a recommendation for the mobile user by a new approach. [ABSTRACT FROM AUTHOR]

To address the problem that the existing time-aware methods always recommend out-of-fashion items to users, this paper proposes a novel method named Item Life Cycle based Collaborative Filtering (ItemLC-CF), taking both user's preference and item's popularity into consideration. This method presents a life cycle function to simulate the variation of item's popularity and integrates such variation with CF to learn the relative preference for items by reranking the candidate set of CF according to item's vitality. Given that it is extremely complicated to construct a life cycle function for each item, items are clustered into different categories via their popularities instead of original product categories. Meanwhile, a SVM ensemble classifier based on AdaBoost is employed to find an appropriate category for new arrival items. Evaluation on MovieLens-1M dataset demonstrates that the proposed method can improve the performance of recommendation list, in turn providing more reasonable and popular recommendation lists for users. [ABSTRACT FROM AUTHOR]

Recent advancements in web personalization techniques facilitate enhanced web-based services that allow recommender systems (RSs) to incorporate contextual knowledge about users and items as an additional dimension into recommendation process. Context-awareness is one of the important aspects of ubiquitous computing to support cognitive environment and provide services in various e-commerce recommendation applications. Tracking each user's preferences over various contextual dimensions from their past transactions and providing personalized recommendations to them are the essence of context-aware recommender systems (CARSs). Conventional paradigms for incorporating context in recommendation process cannot fully cover the challenges on several levels of a context-aware system. Our proposed scheme is based on the hybridization of two complementary techniques, collaborative filtering (CF) and reclusive method (RM) to make context valuable at each level of users' preferences and improve predictive capability of CARSs. Further, a fuzzy real-coded genetic algorithm (Fuzzy-RCGA) approach is incorporated for identifying the influential contextual situations and handling the uncertainty of users' preferences under various contextual situations. Furthermore, users' demographic features are utilized for alleviating the problem of data sparsity. The empirical results on two real-world benchmark datasets clearly demonstrate the effectiveness of our proposed schemes for CARS framework. [ABSTRACT FROM AUTHOR]

The search for unfamiliar experiences and novelty is one of the main drivers behind all human activities, equally important with harm avoidance and reward dependence. A recommender system personalizes suggestions to individuals to support and guide them in their exploration tasks. Personalization mechanisms and recommender systems limit serendipitous encounters by selectively guessing the next item to show to users and potentially leading them into so-called filter bubbles. In the ideal case, these recommendations, except of being accurate, should be also novel. However, up to now most platforms fail to provide both novel and accurate recommendations. For example, a well-known recommendation algorithm, such as matrix factorization (MF), tries to optimize only the accuracy criterion, while disregarding the novelty of recommended items. In order to counteract the filter bubble, we propose two models, denoted as popularity-based and distance-based NMF, that allow to trade-off the MF performance with respect to the criteria of novelty, while only minimally compromising on accuracy. Our experimental results demonstrate that we attain high accuracy by recommending also novel items. [ABSTRACT FROM AUTHOR]