Social networking has encouraged users to find new ways to create, post, search, collaborate and share information of various forms. Unfortunately there is a lot of data in social networks that is not well-managed, which makes the experience within these networks less than optimal. Therefore people generally need more and more time as well as advanced tools that are used for seeking relevant information. A new search paradigm is emerging, where the user perspective is completely reversed: from finding to being found. The aim of present thesis research is to evaluate two approaches of identifying content of interest: user-initiated and system-initiated. The most suitable approaches will be implemented. Various recommendation systems for system-initiated content recommendations will also be investigated, and the best suited ones implemented. The analysis that was performed demonstrated that the users have used all of the implemented approaches and have provided positive and negative comments for all of them, which reinforces the belief that the methods for the implementation were selected correctly. The results of the user testing of the methods were evaluated based on the amount of time it took the users to find the desirable content and on the correspondence of the result compared to the user expectations.

Recommendation Systems or Recommender Systems have become widely popular due to surge of information at present time and consumer centric environment. Researchers have looked into a wide range of recommendation systems leveraging a wide range of algorithms. This study investigates three popular recommendation systems in existence, Collaborative Filtering, Content-Based Filtering, and Hybrid recommendation system. The famous MovieLens dataset was utilized for the purpose of this study. The evaluation looked into both quantitative and qualitative aspects of the recommendation systems. We found that from both the perspectives, the hybrid recommendation system performs comparatively better than standalone Collaborative Filtering or Content-Based Filtering recommendation system

Many employment services base their online job recommendations to users based solely on explicit data in their profiles. The implicit data of what users for example click on, save and mark as irrelevant goes unused. Instead of making recommendations based on user behavior they make a direct comparison between user preferences and job ad attributes. A reason for this is the concern that the inclusion of implicit data can give odd recommendations resulting in a loss of credibility for the service. However, as research has shown this to be of great advantage to recommender systems. In this paper I implement a job recommender and test it both with user data including interaction history with job ads as well as with only explicit data. The results of the recommender with implicit data got better overall performance, but negligible gain in the ratio between true and false positives, or in other words the ratio between correct and incorrect recommendations.

With an overwhelming number of movies available globally, it can be a daunting task for users to find movies that cater to their individual preferences. The vast selection can often leave people feeling overwhelmed, making it challenging to pick a suitable movie. As a result, movie service providers need to offer a recommendation system that adds value to their customers. A movie recommendation system can help customers in this regard by providing a process that assists in finding movies that match their preferences. Previous studies on recommendation systems that use Machine Learning (ML) algorithms have demonstrated that these algorithms outperform some of the existing recommendation methods regarding recommendation strategy. However, there is still room for further improvement, especially when it comes to exploring scenarios where users need to spend a considerable amount of time finding movies related to their preferred genres. This prolonged search for the right movies can give rise to problems such as data sparsity and cold start. To address these issues, we propose a machine learning-based recommender system for movie genres using the K-nearest Neighbours (KNN) algorithm. Our final system utilizes a slider bar on a Streamlit web app, allowing users to select their preferred movies and see recommendations for similar movies. By incorporating user preferences, our system provides personalized recommendations that are more likely to meet the user's interests and preferences. To address our research question: “How and to what extent can a machine learning-based recommender system be developed focusing on movie genres where movie popularity can be predicted based on its content?” we propose three main research objectives. Firstly, we investigate the employment of a classification algorithm in recommending movies focusing on interest genres. Secondly, we evaluate the performance of our classification algorithm concerning movie viewers. Thirdly, we represent the popularity of movie genres based on the content and investigate how this representation can inform the movie recommendation algorithm. On the heels of an experimental strategy, we extract and pre-process a dataset of movies and their associated genre labels from Kaggle. The dataset consists of two files derived from The Movie Database (TMDB) 5000 Movie Dataset. We develop a machine learning-based recommender system based on the similarity of movie genres using the extracted and pre-processed dataset. We vary the KNN algorithm with a slider bar to recommend movies of varying similarity to the selected movie, ranging from similar to diverse in genre. This approach can suggest movies with different titles for users with diverse preferences. We evaluate the performance of the KNN classification algorithm using a user's interest genres, measuring its accuracy, precision, recall, and F1-score. The algorithm's accuracy ranges from low to moderate across different values of K, indicating its moderate effectiveness in predicting user preferences. The algorithm's precision ranges from moderate to high, implying that it provides accurate recommendations to the user. The recall score improves with increasing K and reaches its maximum at K=15, demonstrating its ability to retrieve relevant recommendations. The algorithm achieves a good balance between precision and recall, with an average F1-score of 0.60. This means that the algorithm can accurately identify relevant movies and recommend them to users with a high degree of accuracy. Furthermore, our result shows that the popularity visualization technique using KNN is a powerful tool for analysing and understanding the popularity of different movie genres, which can inform important decisions related to marketing, distribution, and production in the movie industry. In conclusion, our machine learning-based recommender system using KNN for movie genres is a game changer. It allows users to select their preferred movies and see recommendations for similar movies using a slider bar on a Streamlit web app. If confirmed by future research, the promising findings of this thesis can pave the way for developing and incorporating other classification algorithms and features for movie recommendation and evaluation. Furthermore, the adjustable slider bar ranges on the Streamlit web app allow users to customize their movie preferences and receive tailored recommendations.

The amount of video content online will nearly triple in quantity by 2021 compared to 2016. The implementation of sophisticated filters is of paramount importance to manage this information flow. The research question of this thesis asks to what extent it is possible to generate personal recommendations, based on the data that news videos implies. The objective is to evaluate how different recommender systems compare to complete random, each other and how they are received by users in a test environment. This study was performed during the spring of 2018, and explore four different algorithms. These recommender systems include a content-based, a collaborative-filter, a hybrid model and a popularity model as a baseline. The dataset originates from a news media startup called Newstag, who provide video news on a global scale. The data is sparse and includes implicit feedback only. Three offline experiments and a user test were performed. The metric that guided the algorithms offline performance was their recall at 5 and 10, due to the fact that the top list of recommended items are of most interest. A comparison was done on different amounts of meta-data included during training. Another test explored respective algorithms performance as the density of the data increased. In the user test, a mean opinion score was calculated based on the quality of recommendations that each of the algorithms generated for the test subjects. The user test also included randomly sampled news videos to compare with as a baseline. The results indicate that for this specific setting and data set, the content-based recommender system performed best in both the recall at five and ten, as well as in the user test. All of the algorithms outperformed the random baseline. / Mängden video som finns tillgänglig på internet förväntas att tredubblas år 2021 jämfört med 2016. Detta innebär ett behov av sofistikerade filter för att kunna hantera detta informationsflöde. Detta examensarbete ämnar att svara på till vilken grad det går att generera personliga rekommendationer baserat på det data som nyhetsvideo innebär. Syftet är att utvärdera och jämföra olika rekommendationssystem och hur de står sig i ett användartest. Studien utfördes under våren 2018 och utvärderar fyra olika algoritmer. Dessa olika rekommendationssystem innefattar tekniker som content-based, collaborative-filter, hybrid och en popularitetsmodell används som basvärde. Det dataset som används är glest och har endast implicita attribut. Tre experiment utförs samt ett användartest. Mätpunkten för algoritmernas prestanda utgjordes av recall at 5 och recall at 10, dvs. att man mäter hur väl algoritmerna lyckas generera värdefulla rekommendationer i en topp-fem respektive topp-10-lista av videoklipp. Detta då det är av intresse att ha de mest relevanta videorna högst upp i sin lista av resultat. En jämförelse gjordes mellan olika mängd metadata som inkluderades vid träning. Ett annat test gick ut på att utforska hur algoritmerna presterar då datasetet blir mindre glest. I användartestet användes en utvärderingsmetod kallad mean-opinion-score och denna räknades ut per algoritm genom att testanvändare gav betyg på respektive rekommendation, baserat på hur intressant videon var för dem. Användartestet inkluderade även slumpmässigt generade videos för att kunna jämföras i form av basvärde. Resultaten indikerar, för detta dataset, att algoritmen content-based presterar bäst både med hänsyn till recall at 5 & 10 samt den totala poängen i användartestet. Alla algoritmer presterade bättre än slumpen.

This work deals with the issue of poviding recommendations for individual users of e-shop based on the obtained user preferences. The work includes an overview of existing recommender systems, their methods of getting user preferences, the methods of using objects' content and recommender algorithms. An integral part of this work is design and implementated for independent software component for Content-based recommendation. Component is able to receive various user preferences and various forms of object's input data. The component also contains various processing methods for implicit feedback and various methods for making recommendations. Component is written in the Java programming language and uses a PostgreSQL database. The thesis also includes experiments that was carried out with usage of component designed on datasets slantour.cz and antikvariat-ichtys.cz e-shops.

A fim de auxiliar usuários durante o consumo de produtos, sistemas Web passaram a incorporar módulos de recomendação de itens. As abordagens mais populares são a baseada em conteúdo, que recomenda itens a partir de características que são do seu interesse, e a filtragem colaborativa, que recomenda itens bem avaliados por usuários com perfis semelhantes ao do usuário alvo, ou que são semelhantes aos que foram bem avaliados pelo usuário alvo. Enquanto que a primeira abordagem apresenta limitações como a sobre-especialização e a análise limitada de conteúdo, a segunda enfrenta problemas como o novo usuário e/ou novo item, também conhecido como partida fria. Apesar da variedade de técnicas disponíveis, um problema comum existente na maioria das abordagens é a falta de informações semânticas para representar os itens do acervo. Trabalhos recentes na área de Sistemas de Recomendação têm estudado a possibilidade de usar bases de conhecimento da Web como fonte de informações semânticas. Contudo, ainda é necessário investigar como usufruir de tais informações e integrá-las de modo eficiente em sistemas de recomendação. Dessa maneira, este trabalho tem o objetivo de investigar como informações semânticas provenientes de bases de conhecimento podem beneficiar sistemas de recomendação por meio da descrição semântica de itens, e como o cálculo da similaridade semântica pode amenizar o desafio enfrentado no cenário de partida fria. Como resultado, obtém-se uma técnica que pode gerar recomendações adequadas ao perfil dos usuários, incluindo itens novos do acervo que sejam relevantes. Pode-se observar uma melhora de até 10% no RMSE, no cenário de partida fria, quando se compara o sistema proposto com o sistema cuja predição de notas é baseada na correlação de notas. / In order to support users during the consumption of products,Web systems have incorporated recommendation techniques. The most popular approaches are content-based, which recommends items based on interesting features to the user, and collaborative filtering, which recommends items that were well evaluated by users with similar preferences to the target user, or that have similar features to items which were positively evaluated. While the first approach has limitations such as overspecialization and limited content analysis, the second technique has problems such as the new user and the new item, limitation also known as cold start. In spite of the variety of techniques available, a common problem is the lack of semantic information to represent items features. Recent works in the field of recommender systems have been studying the possibility to use knowledge databases from the Web as a source of semantic information. However, it is still necessary to investigate how to use and integrate such semantic information in recommender systems. In this way, this work has the proposal to investigate how semantic information gathered from knowledge databases can help recommender systems by semantically describing items, and how semantic similarity can overcome the challenge confronted in the cold-start scenario. As a result, we obtained a technique that can produce recommendations suited to users profiles, including relevant new items available in the database. It can be observed an improvement of up to 10% in the RMSE in the cold start scenario when comparing the proposed system with the system whose rating prediction is based on the correlation of rates.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-10-21T12:12:38Z No. of bitstreams: 1 Marcos de Meira Góis_.pdf: 1916593 bytes, checksum: e5b2eae456a204d1173418cd2ed3480f (MD5) / Made available in DSpace on 2015-10-21T12:12:38Z (GMT). No. of bitstreams: 1 Marcos de Meira Góis_.pdf: 1916593 bytes, checksum: e5b2eae456a204d1173418cd2ed3480f (MD5) Previous issue date: 2015-08-04 / Nenhuma / Os Sistemas de Recomendação já estão consolidados como ferramentas que apoiam os usuários a superar as dificuldades geradas pelo volume excessivo de conteúdos disponíveis em formato digital, tendo sido projetados para realizar de forma automatizada as tarefas de classificação de conteúdos e de relacionamento deste com interesses e necessidades dos usuários. Um dos problemas ainda observados nestes sistemas está relacionado com a fragilidade de algumas abordagens de classificação e relacionamento de conteúdo que se baseiam principalmente em aspectos sintáticos dos conteúdos tratados. Os sistemas de recomendação baseados em conhecimento buscam mitigar este problema a partir da incorporação de elementos semânticos nos processos de indexação e relacionamento dos materiais. Apesar de bons resultados observados, ainda são identificadas necessidades de investigação, tanto nas atividades de classificação dos conteúdos, como na representação e tratamento dos relacionamentos entre conteúdos e possíveis interessados. Este trabalho busca colaborar com o desenvolvimento nesta área a partir da proposta de um sistema de recomendação baseado em conhecimento e voltado para a recomendação de materiais educacionais em um contexto de pequenos grupos de estudantes. O diferencial deste sistema se dá através de um processo de incorporação da semântica associada com os assuntos tratados e também com a utilização de aspectos semânticos para representar as necessidades e relacionamentos originados pelos usuários do sistema. O principal diferencial deste sistema está localizado na utilização de um algoritmo de recomendação híbrido, no qual tanto aspectos sintáticos como semânticos são empregados. Para avaliar o sistema de recomendação proposto, foi realizada a sua prototipação e teste em um ambiente controlado. / The Recommendation systems are already established as tools that support users to overcome the difficulties caused by the excessive volume of content available in digital format and was designed to conduct automated the content classification tasks and relationship of this with wins users. One of the problems observed in these systems is related to the weakness of some classification approaches and content relationship rely mainly on methodical aspects of the discussed subjects. Recommendation systems based on knowledge seek to mitigate this problem from the incorporation of semantic elements in the indexing processes and material relationship. Despite good results observed, research needs are also identified, both used to classify content activities, such as the representation and treatment of relationships between content and potential stakeholders. This paper seeks to contribute to the development in this area from the proposal for a recommendation system based on knowledge and facing the recommendation of educational materials in a context of small groups of students. The spread of this system is through a semantics of the merger process associated with these types of concerns and also with the use of semantic aspects to represent the needs and relationships originated by system users. The main distinguishing feature of this system is located in the use of a hybrid recommendation algorithm in which both syntactic and semantic aspects are employed. To evaluate the proposed recommendation system, it is due for prototyping and testing in a controlled environment.

As information continues to grow at a very fast pace, our ability to access this information effectively does not, and we are often realize how harder is getting to locate an object quickly and easily. The so-called personalization technology is one of the best solutions to this information overload problem: by automatically learning the user profile, personalized information services have the potential to offer users a more proactive and intelligent form of information access that is designed to assist us in finding interesting objects. Recommender systems, which have emerged as a solution to minimize the problem of information overload, provide us with recommendations of content suited to our needs. In order to provide recommendations as close as possible to a user&rsquo / s taste, personalized recommender systems require accurate user models of characteristics, preferences and needs. Collaborative filtering is a widely accepted technique to provide recommendations based on ratings of similar users, But it suffers from several issues like data sparsity and cold start. In one-class collaborative filtering, a special type of collaborative filtering methods that aims to deal with datasets that lack counter-examples, the challenge is even greater, since these datasets are even sparser. In this thesis, we present a series of experiments conducted on a real-life customer purchase database from a major Turkish E-Commerce site. The sparsity problem is handled by the use of content-based technique combined with TFIDF weights, memory based collaborative filtering combined with different similarity measures and also hybrids approaches, and also model based collaborative filtering with the use of Singular Value Decomposition (SVD). Our study showed that the binary similarity measure and SVD outperform conventional measures in this OCCF dataset.

The tremendous growth of Web has made information overload problem increasingly serious. Users are often confused by huge amount of information available on the internet and they are faced with the problem of finding the most relevant information that meets their needs. Recommender systems have proven to be an important solution approach to this problem. This thesis will present OPENMORE, a movie recommendation system, which is primarily based on content-based filtering technique. The distinctive point of this study lies in the methodology used to construct and update user and item profiles and the optimizations used to fine-tune the constructed user models. The proposed system arranges movie content data as features of a set of dimension slots, where each feature is assigned a stable feature weight regardless of individual movies. These feature weights and the explicit feedbacks provided by the user are then used to construct the user profile, which is fine-tuned through a set of optimization mechanisms. Users are enabled to view their profile, update them and create multiple contexts where they can provide negative and positive feedback for the movies on the feature level.