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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Vybudování efektivního Competitive intelligence systému v společnosti XXX / Building an Effective Competitive Intelligence System for XXX Corporation

Michalko, Miroslav January 2009 (has links)
This diploma thesis results from the need for Competitive Intelligence as a system for gathering, analyzing and communicating information about competitors to obtain a competitive advantage. The work attempts to analyze current knowledge gathering processes as well as an application of that information for strategic decision making inside the XXX corporation. After definition of basic terms several different methods and approaches to Competitive Intelligence are described. These methods are reviewed and those that suit XXX requirements best are picked up afterwards. In this thesis there are also identified some of the crucial information sources, to begin with public and commercial databases and catalogues, business publications, online sources, personal knowledge, but also data-mining and other sophisticated methods. The main contribution of this work is the proposal of Competitive Intelligence system itself, empathising an effective functionality that solves identified issues, and is based on our theoretical resources and on actual competence of the company.
52

The effectiveness of social media marketing communication for institutions of higher education

Bentley-Steyn, Lesmarie January 2019 (has links)
Thesis (MTech (Public Relations Management))--Cape Peninsula University of Technology, 2019 / Several studies have been done showing that universities across the world are using social media platforms, to a lesser or greater degree, in their marketing communication strategies; however, the success of this recruitment method is relatively untested. In order to determine the effectiveness of social media marketing communication on potential university students’ selection of a university, first-year students from the University of Johannesburg were studied. Through a quantitative descriptive research study using a non-probability sampling technique and online electronic questionnaire, it was found that potential university students fall mainly within the Generation Z category (14 – 22 years old). Ninety-eight percent of the respondents in this study indicated that they used social media on a regular basis, however only 37.4% used social media in their choice of a university. More than half (58.3%) of the respondents visited university social media platforms prior to applying in order to look for information about the university, with 33% indicating that they visited these platforms to experience the culture of the university. The study has found that potential students do indeed visit multiple university social media platforms to compare university offerings, but that these platforms are currently not in the top five information sources that they consult in their university search process. Facebook is the most consulted social media platform for this purpose, taking the sixth place on the list of information sources consulted. This makes social media a definite contender in the blend of marketing communication tools a university can use to influence a potential student’s choice of study destination. The findings about these Generation Z potential university students, their use of social media, and their information requirements when researching higher education institutions, can provide valuable insights for university marketers and communicators.
53

Informační chování a informační potřeby zemědělců / Information behavior and information needs of farmers

Křížková, Eva January 2020 (has links)
in English This diploma thesis aims to map information behavior and information needs of farmers. The theoretical part describe these concepts in connection with the field of agriculture and adds a description of information sources that farmers use or may use in practice. The practical part is focused on the formulation and answering of research questions. These questions were answered in qualitative research, which was carried out using in-depth interviews. The research took place in February and March 2020 among farmers in the Benešov region. It brought a large amount of information concerning information needs, used information sources and related information behavior of respondents. These findings can serve as a basis for further research in this area. Keywords: information needs, information behavior, information sources, farmers, Benešov region,
54

The information seeking of undergraduate students and use of electronic resources at KTH Royal Institute of Technology

Ogbekene, Benedicta Ishioma January 2022 (has links)
The aim of this study is to understand the information seeking of undergraduate students and use of electronic resources at KTH Royal Institute of Technology (namely KTH RIT). Four research questions were developed to guide the study. Wilson’s 1996 model of information behaviour was adopted. The survey research design was adopted. A questionnaire was used to collect data, which was administered to a group of undergraduate students through a convenience sampling technique. A total of 122 undergraduate students were sampled from different departments in different years of study (first-to-third). Several statistical tools such as frequency, percentage and Pearson's product-moment correlation coefficient were used to analyse the data. The results obtained from the data analysis revealed that undergraduate students consider all types of information provided as important. Furthermore, books were identified as the most favoured information source that best supports undergraduate students information needs. Next are websites, databases, journals, YouTube and encyclopaedias in ascending order. The study found that what constitutes the information needs of undergraduate students were university study-related tasks, learning, personal roles and research in their order of importance.
55

The Influence of Media Consultation Habits on Young Travelers’ Risk Perception : Exploring Information Seeking Practices in Tourism

Pianigiani, Ivan, Holm, Peter January 2024 (has links)
The thesis investigates the influence of media consultation habits as the developers of risk perceptions among young travelers. It deals with the information-seeking practices of individuals aged 18 to 29 by scrutinizing the extent to which certain media channels are sought out to inform themselves about travel-related risks. By employing a quantitative research approach and collecting data through a web-based questionnaire, the study investigates the role of various information channels by measuring the degree to which they are sought out by the respondents. The findings reveal that legacy media is the most trusted source for risk information among young travelers, surpassing social media and other channels. This unexpected result highlights the significant role of traditional media in shaping risk perceptions despite the prevalence of digital platforms. The study's conclusions are intended to serve tourism professionals and destination managers seeking to enhance communication strategies and manage tourists' risk perceptions effectively.
56

Assessing the e-readiness of the South African Social Security Agency (SASSA) regional office Western Cape and its customers

Davids, Emihiyah 03 1900 (has links)
Thesis (MPA)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: e-Governance refers to the utilisation of technology to improve on service delivery, sharing of information, client participation as well as to advance government through the transformation of its internal and external relationships (Shilubane, 2001:40).e-Governance further implies that government disseminates information and renders services to the public through “electronic means” (Manohar, Pulapa and Mellam, 2009:243). On the other hand, e-government is not entirely about electronic service delivery, but part of the continuous restructuring of government to ensure participation from its partners for improved efficacy and success. Therefore e-government is participatory in nature when implemented correctly. This study assesses and evaluates the current infrastructure and current e-initiatives of the South African Social Security Agency (SASSA) Regional Office Western Cape and the extent to which the agency and its customers are ready to adopt e-government. The e-Governance Road Map (ERM) developed by Ernst & Young India for the New Delhi government was used to guide the researcher to assess the level of e-readiness of the SASSA Regional Office Western Cape. The Information and Communication Technology manager and customer care manager of the SASSA Regional Office Western Cape were interviewed and the beneficiaries of SASSA were requested to participate in the completion of questionnaires. The study found that the customers of SASSA were not as interested in electronic services as in mobile services such as reminders and notifications through short message service (SMS). There are, however, several impediments at SASSA such as an adoption of e-government and m-government, low budget for information and communication technology (ICT) as well as to conduct research among a larger group of SASSA customers. The study mainly recommends that the SASSA Regional Office Western Cape conduct a research study on a larger scale than this research study and to determine the needs of customers in respect of e-services and m-services. Should the agency decide to conduct an e-readiness assessment, the National e-Government Plan (NeGP) of India could be a useful guideline for the implementation of e-governance. The research study strongly recommends that SASSA develops a capacity-building roadmap for the successful implementation of e-governance. / AFRIKAANSE OPSOMMING: e-Regering verwys na die benutting van tegnologie om te verbeter op dienslewering, die deel van inligting, die kliënte deelname te versterk, sowel as om die regering te bevorder deur die transformasie van interne en eksterne verhoudings (Shilubane,2001:40). e-Regering impliseer verder dat die regering inligting versprei en dienste lewer aan die publiek deur middel van "elektroniese metodes" (Manohar, Pulapa en Mellam, 2009:243). Aan die ander kant, e-regering het nie slegs betrekking tot elektroniese dienslewering nie, maar sluit ook in die deurlopende herstrukturering van die regering om deelname van sy vennote te verseker om doeltreffendheid en sukses te bewerkstellig. e-Regering word dus as deelnemend beskou wanneer dit korrek geïmplementeer word. Hierdie studie bepaal en evalueer die huidige infrastruktuur en e-inisiatiewe van die Suid Afrikaanse Agentskap vir Maatskaplike Sekerheid (SAAMS) Streekkantoor Wes-Kaap en die mate waarin die agentskap en sy kliënte gereed is om e-regering aan te neem. Die e-regering kaart wat ontwikkel is deur Ernst en Young Indië vir die Nieu-Delhi regering was gebruik as riglyn om die vlak van e-gereedheid van die SAAMS Streekkantoor Wes-Kaap te bepaal. Onderhoude was gevoer met die Inligting en Kommunikasie tegnologiebestuurder en die kliëntediensbestuurder van die SAAMS Streekkantoor Wes-Kaap en die begunstigdes van SAAMS was versoek om deel te neem in die voltooiing van vraelyste. Die studie het bevind dat die kliënte van SAAMS nie werklik belangstel in elektroniese dienste nie, maar inteendeel aan mobiele dienste, onder andere kennisgewings deur middel van 'n kort boodskap diens. Daar is egter verskeie hindernisse wat die aanvaarding van e-regering en m-regering bemoeilik soos byvoorbeeld 'n lae begroting vir inligting en kommunikasie tegnologie (IKT) asook om navorsing te doen onder 'n groter groep van SAAMS kliënte. Die studie beveel hoofsaaklik aan dat SAAMS Streekkantoor Wes-Kaap 'n navorsingsprojek doen op 'n groter skaal as hierdie navorsing en die behoeftes van kliënte ten opsigte van e-dienste en m-dienste te bepaal. Indien die agentskap besluit om 'n e-gereedheid assessering uit te voer, word die Nasionale e-Regering Plan (NeGP) van Indië aan beveel as 'n nuttige riglyn vir die implementering van e-regering. Die navorsing beveel sterk aan dat SAAMS 'n vermoë-opbouplan vir die suksesvolle implementering van e-regering ontwikkel.
57

Fontes de informação para área financeira: uma proposta de infraestrutura de apoio à análise de investimentos / Sources of information for the financial area: a proposal for infrastructure to support investment analysis.

Cattani, Susana Ducci 25 June 2019 (has links)
Nos dias atuais, o desenvolvimento de um país passa obrigatoriamente por seu Sistema Financeiro, o qual, num mundo globalizado, trabalha em sintonia com outros Sistemas Financeiros. Assim, a incumbência de tais sistemas resume-se a atuar nos fluxos de transferência de ativos financeiros em poder de poupadores para os setores produtivo e/ou de consumo. Tal transferência ocorre por meio de operações de compra, venda e/ou troca desses ativos, no âmbito do que se denomina mercados. Para tanto, faz-se necessário captar, intermediar e aplicar tais ativos, o que é feito por operadores, como os bancos de investimento. Neste trabalho, privilegiando as tarefas realizadas por analistas financeiros de bancos de investimento, os quais prospectam oportunidades de negócio, analisam-nas e as oferecem a investidores, são estudadas as características das fontes de informação utilizadas por estes analistas e o comportamento informacional destes. A pesquisa, de abordagem qualitativa e natureza exploratória, foi conduzida com base em análise da literatura e estudo de caso de um serviço de informação vinculado a um banco de investimento. Dentre os resultados, destacamse a compreensão do comportamento informacional dos analistas de investimentos, sistematização das fontes de informação utilizadas e a proposta de uma infraestrutura de apoio às atividades destes analistas. Conclui-se que tais analistas utilizam informações provenientes de diversas fontes, porém, identificou-se um conjunto de fontes comum aos diversos analistas, bem como, a prática do intercâmbio de informações entre eles. Nesse sentido, frente aos resultados e impactos relativos às transferências de ativos financeiros, os mesmos analistas dependem do acesso a diversas fontes de informações da área financeira, prevalecendo a manutenção dos diversos atributos relativos à qualidade da informação. / Nowadays, the development of a country necessarily passes through its financial system, which, in a globalized world, works in tune with other financial systems. Thus, the task of such systems is to act in the flows of transfer of financial assets in the power of savers to the productive and/or consumption sectors. Such transfer takes place through the purchase, sale and/or exchange of these assets, in the context of what is called market. To do so, it is necessary to capture, intermediate and apply such assets, which is done by operators, such as investment banks. In this work, privileging the tasks performed by financial analysts of investment banks, which prospect business opportunities, analyze and offer them to investors, the characteristics of the sources of information used by these analysts and theirs informational behavior are studied. The research, of qualitative approach and exploratory nature, was conducted based on literature analysis and case study of information service linked to an investment bank. Among the results, we highlight the understanding of the informational behavior of investment analysts, systematization of the sources of information used and the proposal of an infrastructure to support the activities of these analysts. It is concluded that the analysts use information from various sources, however, a set of sources common to the various analysts was identified, as well as the practice of exchange of information between them. In this sense, in the face of the results and impacts related to the transfer of financial assets, the same analysts depend on the access to several sources of information in the financial area, with the maintenance of the various attributes related to information quality.
58

Leitura documentária das fontes de informação jurídica / -

Silva, Andréia Gonçalves 16 December 2008 (has links)
As fontes de informação jurídica são representadas pela doutrina, legislação e jurisprudência. Na literatura da Biblioteconomia e Ciência da Informação não há trabalhos que sistematizem o ato da leitura documentária dessas fontes. Partindo deste pressuposto a presente pesquisa projetou os seguintes objetivos: fornecer subsídios que auxiliem os bibliotecários no acesso e compreensão dos conceitos que permeiam a ciência jurídica; detalhar as características das fontes de informação jurídica, e desenvolver modelo estratégico de leitura técnica da fonte de informação jurisprudencial. Inicialmente, exploraram-se aspectos cognitivos que influenciam o ato de ler. Posteriormente, demonstrou-se a importância da Terminologia e da Lingüística Documentária ao oferecem instrumentos que auxiliam o bibliotecário no conhecimento da terminologia e compreensão das definições da área do Direito, a primeira produzindo a compilação dos termos; a segunda, estruturando e sistematizando os campos conceituais nas áreas de especialidade. Finalizando essa etapa exibiram-se conceitos da indexação e das linguagens documentárias. Prosseguindo com a pesquisa apresentaram-se definições da Ciência do Direito, destacando a estrutura textual dos acórdãos, das leis e dos pareceres jurídicos. Na seqüencia, iniciou-se o desenvolvimento do modelo de leitura técnica jurisprudencial com a exibição de conceitos referentes à dinâmica processual, em especial os procedimentos recursais no âmbito do Superior Tribunal de Justiça - STJ. Na fase de aplicação dos modelos utilizaram-se recursos especiais - RESPs, publicados na Revista Eletrônica da Jurisprudência do STJ. Da avaliação do modelo podem-se tirar as seguintes conclusões: para a compreensão da terminologia jurídica e indexação da decisão judicial (acórdão) é necessário que o bibliotecário aproprie-se dos conceitos jurídicos, entenda as fases do processo judicial e use técnicas estratégicas de leitura para a análise de certas partes do acórdão - a ementa, o voto do relator e, quando necessário, o relatório. Ao utilizar as técnicas sugeridas no modelo ora proposto, o bibliotecário conseguirá indexar o acórdão sem necessariamente lê-lo na íntegra. / The sources of legal information are represented by doctrine, legislation and jurisprudence. In the literature of the Librarian Science and that of the Information Science there are not works that systematize the act of the documentary reading of these sources. Therefore, the present research aims at: providing useful information to the librarians in the access and comprehension of the concepts of the legal science; detailing the characteristics of the sources of legal information; and developing a strategic model for the technical reading of the jurisprudence source of information. Innitially, cognition aspects that influence the act of reading were explored. Later, the importance of terminology and documentary linguistics was demonstrated by offering the librarian useful tools to the understanding of the terminology and definitions of the Law field, firstly by producing a compilation of the terms and then by structuring and systematizing conceptual fields in the specific areas. This stage of the research ends by displaying concepts of the index process and documentary languages. Next, definitions of the Law Science are presented, highlighting the textual framework of the sentence, laws, and legal opinion. There follows the development of the model of jurisprudence technical reading, presenting the concepts related to the dynamics of legal proceedings, specially appeal procedures to the Superior Tribunal de Justiça - STJ (Upper Court of Appeals). In the stage of application of the model, court decisions related to specials appeals - RESPs - published in the \"Revista Eletrônica da Jurisprudência do STJ\" were used. Upon evaluation of the model, the following conclusions were drawn: in order to understand the legal terminology and the indexation of the court decision, the librarian must internalize the legal concepts, understand the steps of the legal proceedings, and use reading strategies in the analisys of certain parts of the decision - the summary, the vote of the reporter and, when necessary, the report. By using the techniques suggested in the model, the librarian will be able to index the decision without having to read the whole of the decision.
59

Leitura documentária das fontes de informação jurídica / -

Andréia Gonçalves Silva 16 December 2008 (has links)
As fontes de informação jurídica são representadas pela doutrina, legislação e jurisprudência. Na literatura da Biblioteconomia e Ciência da Informação não há trabalhos que sistematizem o ato da leitura documentária dessas fontes. Partindo deste pressuposto a presente pesquisa projetou os seguintes objetivos: fornecer subsídios que auxiliem os bibliotecários no acesso e compreensão dos conceitos que permeiam a ciência jurídica; detalhar as características das fontes de informação jurídica, e desenvolver modelo estratégico de leitura técnica da fonte de informação jurisprudencial. Inicialmente, exploraram-se aspectos cognitivos que influenciam o ato de ler. Posteriormente, demonstrou-se a importância da Terminologia e da Lingüística Documentária ao oferecem instrumentos que auxiliam o bibliotecário no conhecimento da terminologia e compreensão das definições da área do Direito, a primeira produzindo a compilação dos termos; a segunda, estruturando e sistematizando os campos conceituais nas áreas de especialidade. Finalizando essa etapa exibiram-se conceitos da indexação e das linguagens documentárias. Prosseguindo com a pesquisa apresentaram-se definições da Ciência do Direito, destacando a estrutura textual dos acórdãos, das leis e dos pareceres jurídicos. Na seqüencia, iniciou-se o desenvolvimento do modelo de leitura técnica jurisprudencial com a exibição de conceitos referentes à dinâmica processual, em especial os procedimentos recursais no âmbito do Superior Tribunal de Justiça - STJ. Na fase de aplicação dos modelos utilizaram-se recursos especiais - RESPs, publicados na Revista Eletrônica da Jurisprudência do STJ. Da avaliação do modelo podem-se tirar as seguintes conclusões: para a compreensão da terminologia jurídica e indexação da decisão judicial (acórdão) é necessário que o bibliotecário aproprie-se dos conceitos jurídicos, entenda as fases do processo judicial e use técnicas estratégicas de leitura para a análise de certas partes do acórdão - a ementa, o voto do relator e, quando necessário, o relatório. Ao utilizar as técnicas sugeridas no modelo ora proposto, o bibliotecário conseguirá indexar o acórdão sem necessariamente lê-lo na íntegra. / The sources of legal information are represented by doctrine, legislation and jurisprudence. In the literature of the Librarian Science and that of the Information Science there are not works that systematize the act of the documentary reading of these sources. Therefore, the present research aims at: providing useful information to the librarians in the access and comprehension of the concepts of the legal science; detailing the characteristics of the sources of legal information; and developing a strategic model for the technical reading of the jurisprudence source of information. Innitially, cognition aspects that influence the act of reading were explored. Later, the importance of terminology and documentary linguistics was demonstrated by offering the librarian useful tools to the understanding of the terminology and definitions of the Law field, firstly by producing a compilation of the terms and then by structuring and systematizing conceptual fields in the specific areas. This stage of the research ends by displaying concepts of the index process and documentary languages. Next, definitions of the Law Science are presented, highlighting the textual framework of the sentence, laws, and legal opinion. There follows the development of the model of jurisprudence technical reading, presenting the concepts related to the dynamics of legal proceedings, specially appeal procedures to the Superior Tribunal de Justiça - STJ (Upper Court of Appeals). In the stage of application of the model, court decisions related to specials appeals - RESPs - published in the \"Revista Eletrônica da Jurisprudência do STJ\" were used. Upon evaluation of the model, the following conclusions were drawn: in order to understand the legal terminology and the indexation of the court decision, the librarian must internalize the legal concepts, understand the steps of the legal proceedings, and use reading strategies in the analisys of certain parts of the decision - the summary, the vote of the reporter and, when necessary, the report. By using the techniques suggested in the model, the librarian will be able to index the decision without having to read the whole of the decision.
60

Information sources selection methodology for recommender systems based on intrinsic characteristics and trust measure

Aciar, Silvana Vanesa 18 June 2007 (has links)
El treball desenvolupat en aquesta tesi presenta un profund estudi i proveïx solucions innovadores en el camp dels sistemes recomanadors. Els mètodes que usen aquests sistemes per a realitzar les recomanacions, mètodes com el Filtrat Basat en Continguts (FBC), el Filtrat Col·laboratiu (FC) i el Filtrat Basat en Coneixement (FBC), requereixen informació dels usuaris per a predir les preferències per certs productes. Aquesta informació pot ser demogràfica (Gènere, edat, adreça, etc), o avaluacions donades sobre algun producte que van comprar en el passat o informació sobre els seus interessos. Existeixen dues formes d'obtenir aquesta informació: els usuaris ofereixen explícitament aquesta informació o el sistema pot adquirir la informació implícita disponible en les transaccions o historial de recerca dels usuaris. Per exemple, el sistema recomanador de pel·lícules MovieLens (http://movielens.umn.edu/login) demana als usuaris que avaluïn almenys 15 pel·lícules dintre d'una escala de * a * * * * * (horrible, ...., ha de ser vista). El sistema genera recomanacions sobre la base d'aquestes avaluacions. Quan els usuaris no estan registrat en el sistema i aquest no té informació d'ells, alguns sistemes realitzen les recomanacions tenint en compte l'historial de navegació. Amazon.com (http://www.amazon.com) realitza les recomanacions tenint en compte les recerques que un usuari a fet o recomana el producte més venut. No obstant això, aquests sistemes pateixen de certa falta d'informació. Aquest problema és generalment resolt amb l'adquisició d'informació addicional, se li pregunta als usuaris sobre els seus interessos o es cerca aquesta informació en fonts addicionals. La solució proposada en aquesta tesi és buscar aquesta informació en diverses fonts, específicament aquelles que contenen informació implícita sobre les preferències dels usuaris. Aquestes fonts poden ser estructurades com les bases de dades amb informació de compres o poden ser no estructurades com les pàgines web on els usuaris deixen la seva opinió sobre algun producte que van comprar o posseïxen.Nosaltres trobem tres problemes fonamentals per a aconseguir aquest objectiu: 1 . La identificació de fonts amb informació idònia per als sistemes recomanadors.2 . La definició de criteris que permetin la comparança i selecció de les fonts més idònies. 3 . La recuperació d'informació de fonts no estructurades. En aquest sentit, en la tesi proposada s'ha desenvolupat: 1 . Una metodologia que permet la identificació i selecció de les fonts més idònies. Criteris basats en les característiques de les fonts i una mesura de confiança han estat utilitzats per a resoldre el problema de la identificació i selecció de les fonts. 2 . Un mecanisme per a recuperar la informació no estructurada dels usuaris disponible en la web. Tècniques de Text Mining i ontologies s'han utilitzat per a extreure informació i estructurar-la apropiadament perquè la utilitzin els recomanadors. Les contribucions del treball desenvolupat en aquesta tesi doctoral són: 1. Definició d'un conjunt de característiques per a classificar fonts rellevants per als sistemes recomanadors2. Desenvolupament d'una mesura de rellevància de les fonts calculada sobre la base de les característiques definides3. Aplicació d'una mesura de confiança per a obtenir les fonts més fiables. La confiança es definida des de la perspectiva de millora de la recomanació, una font fiable és aquella que permet millorar les recomanacions. 4. Desenvolupament d'un algorisme per a seleccionar, des d'un conjunt de fonts possibles, les més rellevants i fiable utilitzant les mitjanes esmentades en els punts previs. 5. Definició d'una ontologia per a estructurar la informació sobre les preferències dels usuaris que estan disponibles en Internet. 6. Creació d'un procés de mapatge que extreu automàticament informació de les preferències dels usuaris disponibles en la web i posa aquesta informació dintre de l'ontologia. Aquestes contribucions permeten aconseguir dos objectius importants: 1 . Millorament de les recomanacions usant fonts d'informació alternatives que sigui rellevants i fiables.2 . Obtenir informació implícita dels usuaris disponible en Internet. / The work developed in this thesis presents an in-depth study and provides innovative solutions in the field of recommender systems. The methods used by these systems to carry out recommendations, such as Content-Based Filtering (CBF), Collaborative Filtering (CF) and Knowledge-Based Filtering (KBF), require information from users to predict preferences for certain products. This may be demographic information (genre, age and address), evaluations given to certain products in the past or information about their interests. There are two ways of obtaining this information: users offer it explicitly or the system can retrieve the implicit information available in the purchase and search history. For example, the movie recommender system MovieLens (http://movielens.umn.edu/login) asks users to rate at least 15 movies on a scale of * to * * * * * (awful, ... , must be seen). The system generates recommendations based on these evaluations. When users are not registered into the site and it has no information about them, recommender systems make recommendations according to the site search history. Amazon.com (http://www.amazon.com) make recommendations according to the site search history or recommend the best selling products. Nevertheless, these systems suffer from a certain lack of information. This problem is generally solved with the acquisition of additional information; users are asked about their interests or that information is searched for in additional available sources. The solution proposed in this thesis is to look for that information in various sources, specifically those that contain implicit information about user preferences. These sources can be structured like databases with purchasing information or they can be unstructured sources like review pages where users write their experiences and opinions about a product they buy or possess.We have found three fundamental problems to achieve this objective: 1. The identification of sources with suitable information for recommender systems.2. The definition of criteria that allows the comparison and selection of the most suitable sources.3. Retrieving the information from unstructured sources.In this sense, the proposed thesis has developed:1. A methodology that allows the identification and selection of the most suitable sources. Criteria based on the characteristics of sources and a trust measure have been used to solve the problem of identifying and selecting sources.2. A mechanism to retrieve unstructured information from users available on the Web. Text mining techniques and ontologies have been used to extract information and structure it appropriately for use by the recommenders.The contributions of the work developed in this doctoral thesis are:1. Definition of a set of characteristics to classify relevant sources of information for recommender systems.2. Development of a measure of relevance of sources according to characteristics defined in previous point.3. Application of a trust measure to obtain the most reliable sources. Confidence is measured from the perspective of improving the recommendation; a reliable source is one that leads to improved recommendations.4. Development of an algorithm to select, from a set of possible sources, the most relevant and reliable ones according to measures defined in previous points.5. Definition of an ontology to structure information about user preferences that are available on the Internet.6. The creation of a mapping process that automatically extracts information about user preferences available on the web and put in the ontology.These contributions allow us the achievement of two important objectives:1. Improving recommendations using alternative sources of information that are relevant and trustworthy.2. Obtaining implicit information about user available on the Internet.

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