A probabilistic approach for cluster based polyrepresentative information retrieval

A thesis submitted to the University of Bedfordshire in partial ful lment of the requirements for the degree of Doctor of PhilosophyDocument clustering in information retrieval (IR) is considered an alternative to rank-based retrieval approaches, because of its potential to support user interactions beyond just typing in queries. Similarly, the Principle of Polyrepresentation (multi-evidence: combining multiple cognitively and/or functionally diff erent information need or information object representations for improving an IR system's performance) is an established approach in cognitive IR with plausible applicability in the domain of information seeking and retrieval. The combination of these two approaches can assimilate their respective individual strengths in order to further improve the performance of IR systems. The main goal of this study is to combine cognitive and cluster-based IR approaches for improving the eff ectiveness of (interactive) information retrieval systems. In order to achieve this goal, polyrepresentative information retrieval strategies for cluster browsing and retrieval have been designed, focusing on the evaluation aspect of such strategies. This thesis addresses the challenge of designing and evaluating an Optimum Clustering Framework (OCF) based model, implementing probabilistic document clustering for interactive IR. Thus, polyrepresentative cluster browsing strategies have been devised. With these strategies a simulated user based method has been adopted for evaluating the polyrepresentative cluster browsing and searching strategies. The proposed approaches are evaluated for information need based polyrepresentative clustering as well as document based polyrepresentation and the combination thereof. For document-based polyrepresentation, the notion of citation context is exploited, which has special applications in scientometrics and bibliometrics for science literature modelling. The information need polyrepresentation, on the other hand, utilizes the various aspects of user information need, which is crucial for enhancing the retrieval performance. Besides describing a probabilistic framework for polyrepresentative document clustering, one of the main fi ndings of this work is that the proposed combination of the Principle of Polyrepresentation with document clustering has the potential of enhancing the user interactions with an IR system, provided that the various representations of information need and information objects are utilized. The thesis also explores interactive IR approaches in the context of polyrepresentative interactive information retrieval when it is combined with document clustering methods. Experiments suggest there is a potential in the proposed cluster-based polyrepresentation approach, since statistically signifi cant improvements were found when comparing the approach to a BM25-based baseline in an ideal scenario. Further marginal improvements were observed when cluster-based re-ranking and cluster-ranking based comparisons were made. The performance of the approach depends on the underlying information object and information need representations used, which confi rms fi ndings of previous studies where the Principle of Polyrepresentation was applied in diff erent ways

From social tagging to polyrepresentation: a study of expert annotating behavior of moving images

Mención Internacional en el título de doctorThis thesis investigates “nichesourcing” (De Boer, Hildebrand, et al., 2012), an emergent initiative of cultural heritage crowdsoucing in which niches of experts are involved in the annotating tasks. This initiative is studied in relation to moving image annotation, and in the context of audiovisual heritage, more specifically, within the sector of film archives. The work presents a case study of film and media scholars to investigate the types of annotations and attribute descriptions that they could eventually contribute, as well as the information needs, and seeking and searching behaviors of this group, in order to determine what the role of the different types of annotations in supporting their expert tasks would be. The study is composed of three independent but interconnected studies using a mixed methodology and an interpretive approach. It uses concepts from the information behavior discipline, and the "Integrated Information Seeking and Retrieval Framework" (IS&R) (Ingwersen and Järvelin, 2005) as guidance for the investigation. The findings show that there are several types of annotations that moving image experts could contribute to a nichesourcing initiative, of which time-based tags are only one of the possibilities. The findings also indicate that for the different foci in film and media research, in-depth indexing at the content level is only needed for supporting a specific research focus, for supporting research in other domains, or for engaging broader audiences. The main implications at the level of information infrastructure are the requirement for more varied annotating support, more interoperability among existing metadata standards and frameworks, and the need for guidelines about crowdsoucing and nichesourcing implementation in the audiovisual heritage sector. This research presents contributions to the studies of social tagging applied to moving images, to the discipline of information behavior, by proposing new concepts related to the area of use behavior, and to the concept of “polyrepresentation” (Ingwersen, 1992, 1996) applied to the humanities domain.Esta tesis investiga la iniciativa del nichesourcing (De Boer, Hildebrand, et al., 2012), como una forma de crowdsoucing en sector del patrimonio cultural, en la cuál grupos de expertos participan en las tareas de anotación de las colecciones. El ámbito de aplicación es la anotación de las imágenes en movimiento en el contexto del patrimonio audiovisual, más específicamente, en el caso de los archivos fílmicos. El trabajo presenta un estudio de caso aplicado a un dominio específico de expertos en el ámbito audiovisual: los académicos de cine y medios. El análisis se centra en dos aspectos específicos del problema: los tipos de anotaciones y atributos en las descripciones que podrían obtenerse de este nicho de expertos; y en las necesidades de información y el comportamiento informacional de dicho grupo, con el fin de determinar cuál es el rol de los diferentes tipos de anotaciones en sus tareas de investigación. La tesis se compone de tres estudios independientes e interconectados; se usa una metodología mixta e interpretativa. El marco teórico se compone de conceptos del área de estudios de comportamiento informacional (“information behavior”) y del “Marco integrado de búsqueda y recuperación de la información” ("Integrated Information Seeking and Retrieval Framework" (IS&R)) propuesto por Ingwersen y Järvelin (2005), que sirven de guía para la investigación. Los hallazgos indican que existen diversas formas de anotación de la imagen en movimiento que podrían generarse a partir de las contribuciones de expertos, de las cuáles las etiquetas a nivel de plano son sólo una de las posibilidades. Igualmente, se identificaron diversos focos de investigación en el área académica de cine y medios. La indexación detallada de contenidos sólo es requerida por uno de esos grupos y por investigadores de otras disciplinas, o como forma de involucrar audiencias más amplias. Las implicaciones más relevantes, a nivel de la infraestructura informacional, se refieren a los requisitos de soporte a formas más variadas de anotación, el requisito de mayor interoperabilidad de los estándares y marcos de metadatos, y la necesidad de publicación de guías de buenas prácticas sobre de cómo implementar iniciativas de crowdsoucing o nichesourcing en el sector del patrimonio audiovisual. Este trabajo presenta aportes a la investigación sobre el etiquetado social aplicado a las imágenes en movimiento, a la disciplina de estudios del comportamiento informacional, a la que se proponen nuevos conceptos relacionados con el área de uso de la información, y al concepto de “poli-representación” (Ingwersen, 1992, 1996) en las disciplinas humanísticas.Programa Oficial de Doctorado en Documentación: Archivos y Bibliotecas en el Entorno DigitalPresidente: Peter Emil Rerup Ingwersen.- Secretario: Antonio Hernández Pérez.- Vocal: Nils Phar

Implicit feedback for interactive information retrieval

Searchers can find the construction of query statements for submission to Information Retrieval (IR) systems a problematic activity. These problems are confounded by uncertainty about the information they are searching for, or an unfamiliarity with the retrieval system being used or collection being searched. On the World Wide Web these problems are potentially more acute as searchers receive little or no training in how to search effectively. Relevance feedback (RF) techniques allow searchers to directly communicate what information is relevant and help them construct improved query statements. However, the techniques require explicit relevance assessments that intrude on searchers’ primary lines of activity and as such, searchers may be unwilling to provide this feedback. Implicit feedback systems are unobtrusive and make inferences of what is relevant based on searcher interaction. They gather information to better represent searcher needs whilst minimising the burden of explicitly reformulating queries or directly providing relevance information. In this thesis I investigate implicit feedback techniques for interactive information retrieval. The techniques proposed aim to increase the quality and quantity of searcher interaction and use this interaction to infer searcher interests. I develop search interfaces that use representations of the top-ranked retrieved documents such as sentences and summaries to encourage a deeper examination of search results and drive the information seeking process. Implicit feedback frameworks based on heuristic and probabilistic approaches are described. These frameworks use interaction to identify needs and estimate changes in these needs during a search. The evidence gathered is used to modify search queries and make new search decisions such as re-searching the document collection or restructuring already retrieved information. The term selection models from the frameworks and elsewhere are evaluated using a simulation-based evaluation methodology that allows different search scenarios to be modelled. Findings show that the probabilistic term selection model generated the most effective search queries and learned what was relevant in the shortest time. Different versions of an interface that implements the probabilistic framework are evaluated to test it with human subjects and investigate how much control they want over its decisions. The experiment involved 48 subjects with different skill levels and search experience. The results show that searchers are happy to delegate responsibility to RF systems for relevance assessment (through implicit feedback), but not more severe search decisions such as formulating queries or selecting retrieval strategies. Systems that help searchers make these decisions are preferred to those that act directly on their behalf or await searcher action

Navigation, findability and the usage of cultural heritage on the web: an exploratory study

The present thesis investigates the usage of cultural heritage resources on the web. In recent years cultural heritage objects has been digitalized and made available on the web for the general public to use. The thesis addresses to what extent the digitalized material is used, and how findable it is on the web. On the web resources needs to be findable in order to be visited and used. The study is done at the intersection of several research areas in Library and Information Science; Information Seeking/Human Information Behaviour, Interactive Information Retrieval, and Webometrics. The two thesis research questions focus on different aspects of the study: (1) findability on the web; and (2) the usage and the users. The usage of the cultural heritage is analysed with Savolainen’s Everyday Life Information Seeking (ELIS) framework. The IS&R framework by Ingwersen and Järvelin is the main theoretical foundation, and a conceptual framework is developed so the examined aspects could be related to each other more clearly. An important distinction in the framework is between object and resource. An object is a single document, file or html page, whereas a resource is a collection of objects, e.g. a cultural heritage web site. Three webometric levels are used to both combine and distinguish the data types: usage, content, and structure. The interaction between the system and its users’ information search process was divided into query dependent and query independent aspects. The query dependent aspects contain the information need on the user side and the topic of the content on the system side. The query independent aspects are the structural findability on the system side and the users search skills on the user side. The conceptual framework is summarised in the User-Resource Interaction (URI) model. The research design is a methodological triangulation, in the form of a mixed methods approach in order to obtain measures and indicators of the resources and the usage from different angels. Four methods are used: site structure analysis; log analysis; web survey; and findability analysis. The research design is both sequential and parallel, the site structure analysis preceded the log analysis and the findability analysis, and the web survey was employed independent of the other methods. Three Danish resources are studied: Arkiv for Dansk Litteratur (ADL), a collection of literary texts written by authors; Kunst Index Danmark (KID), an index of the holdings in the Danish art museums; and Guaman Poma Inch Chronicle (Poma), a digitalized manuscript on the UNESCO list of World cultural heritage. The studied log covers all usage during the period October to December 2010. The site structure is analysed so the resources can be described as different levels, based on function and content. The results from the site structure analysis are used both in the log analysis and the findability analysis, as well as a way to describe the resources. In the log analysis navigation strategies and navigation patterns are studied. Navigation through a web search engine is the most common way to reach the resources, but both direct navigation and link navigation are also used in all three resources. Most users arrive in the middle level in ADL and KID, at information on authors and artists. On average cultural heritage objects are viewed in half of the session. In the analysis of the web survey answers two groups of users’ are distinguished, the professional user in a work context and users in a hobby or leisure context. School or study as a context is prominent in Guaman Poma, the Inca Chronicle. Generally are pages about the cultural heritage more frequently visited than the digitized cultural heritage objects. In the findability framework six aspects are identified as central for the findability of an object on the web: attributes of the object, accessibility, internal navigation, internal search, reachability and web prestige. The six aspects are evaluated through seven indicators. All studied objects are findable in the analysis using the findability framework. A findability issue in KID is the use of the secure https protocol instead of http, which leads to the objects in KID having no PageRank value in Google and thereby a lower ranking in comparison to similar objects with a PageRank value. The internal findability is reduced for the objects in top of all three resources, e.g. the first page, due to the focus of the internal search engine on the cultural heritage objects. Several possible adjustment or developments of the findability frameworks is discussed, such as changing the weightning between the aspects measured, alternative scores and automated measuring. In conclusion, the investigation adds to our knowledge about how resources with digitalized cultural heritage are accessed and used, as well as how findable they are. The thesis provides both theoretical and conceptual contributions to research. The IS&R framework has been adapted to the web, the information search process was split into query dependent and query independent aspects, and a whole findability framework has been developed. Both the empirical findings and the theoretical advancements support the development of better access to web resources

Navigation, findability and the usage of cultural heritage on the web:an exploratory study

The present thesis investigates the usage of cultural heritage resources on the web. In recent years cultural heritage objects has been digitalized and made available on the web for the general public to use. The thesis addresses to what extent the digitalized material is used, and how findable it is on the web. On the web resources needs to be findable in order to be visited and used. The study is done at the intersection of several research areas in Library and Information Science; Information Seeking/Human Information Behaviour, Interactive Information Retrieval, and Webometrics. The two thesis research questions focus on different aspects of the study: (1) findability on the web; and (2) the usage and the users. The usage of the cultural heritage is analysed with Savolainen’s Everyday Life Information Seeking (ELIS) framework. The IS&R framework by Ingwersen and Järvelin is the main theoretical foundation, and a conceptual framework is developed so the examined aspects could be related to each other more clearly. An important distinction in the framework is between object and resource. An object is a single document, file or html page, whereas a resource is a collection of objects, e.g. a cultural heritage web site. Three webometric levels are used to both combine and distinguish the data types: usage, content, and structure. The interaction between the system and its users’ information search process was divided into query dependent and query independent aspects. The query dependent aspects contain the information need on the user side and the topic of the content on the system side. The query independent aspects are the structural findability on the system side and the users search skills on the user side. The conceptual framework is summarised in the User-Resource Interaction (URI) model. The research design is a methodological triangulation, in the form of a mixed methods approach in order to obtain measures and indicators of the resources and the usage from different angels. Four methods are used: site structure analysis; log analysis; web survey; and findability analysis. The research design is both sequential and parallel, the site structure analysis preceded the log analysis and the findability analysis, and the web survey was employed independent of the other methods. Three Danish resources are studied: Arkiv for Dansk Litteratur (ADL), a collection of literary texts written by authors; Kunst Index Danmark (KID), an index of the holdings in the Danish art museums; and Guaman Poma Inch Chronicle (Poma), a digitalized manuscript on the UNESCO list of World cultural heritage. The studied log covers all usage during the period October to December 2010. The site structure is analysed so the resources can be described as different levels, based on function and content. The results from the site structure analysis are used both in the log analysis and the findability analysis, as well as a way to describe the resources. In the log analysis navigation strategies and navigation patterns are studied. Navigation through a web search engine is the most common way to reach the resources, but both direct navigation and link navigation are also used in all three resources. Most users arrive in the middle level in ADL and KID, at information on authors and artists. On average cultural heritage objects are viewed in half of the session. In the analysis of the web survey answers two groups of users’ are distinguished, the professional user in a work context and users in a hobby or leisure context. School or study as a context is prominent in Guaman Poma, the Inca Chronicle. Generally are pages about the cultural heritage more frequently visited than the digitized cultural heritage objects. In the findability framework six aspects are identified as central for the findability of an object on the web: attributes of the object, accessibility, internal navigation, internal search, reachability and web prestige. The six aspects are evaluated through seven indicators. All studied objects are findable in the analysis using the findability framework. A findability issue in KID is the use of the secure https protocol instead of http, which leads to the objects in KID having no PageRank value in Google and thereby a lower ranking in comparison to similar objects with a PageRank value. The internal findability is reduced for the objects in top of all three resources, e.g. the first page, due to the focus of the internal search engine on the cultural heritage objects. Several possible adjustment or developments of the findability frameworks is discussed, such as changing the weightning between the aspects measured, alternative scores and automated measuring. In conclusion, the investigation adds to our knowledge about how resources with digitalized cultural heritage are accessed and used, as well as how findable they are. The thesis provides both theoretical and conceptual contributions to research. The IS&R framework has been adapted to the web, the information search process was split into query dependent and query independent aspects, and a whole findability framework has been developed. Both the empirical findings and the theoretical advancements support the development of better access to web resources