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It has previously been determined that using 3 or 4 points on a categorized response scale will fail to produce a continuous distribution of scores. However, there is no evidence, thus far, revealing the number of scale points that may indeed possess an approximate or sufficiently continuous distribution. This study provides the evidence to suggest the level of categorization in discrete scales that makes them directly comparable to continuous scales in terms of their measurement properties. To do this, we first introduced a novel procedure for simulating discretely scaled data that was both informed and validated through the principles of the Classical True Score Model. Second, we employed a measurement invariance (MI) approach to confirmatory factor analysis (CFA) in order to directly compare the measurement quality of continuously scaled factor models to that of discretely scaled models. The simulated design conditions of the study varied with respect to item-specific variance (low, moderate, high), random error variance (none, moderate, high), and discrete scale categorization (number of scale points ranged from 3 to 101). A population analogue approach was taken with respect to sample size (N = 10,000). We concluded that there are conditions under which response scales with 11 to 15 scale points can reproduce the measurement properties of a continuous scale. Using response scales with more than 15 points may be, for the most part, unnecessary. Scales having from 3 to 10 points introduce a significant level of measurement error, and caution should be taken when employing such scales. The implications of this research and future directions are discussed.

I denna studie riktas fokus mot hur samhället ordnar för barns välfärd när de generellt inriktade insatserna inte räcker till. Studien baseras på observationer och intervjuer i tre olika verksamheter för unga i åldern 12-16 år: 1) ett hem för vård eller boende, HVB, med egen skola, 2) en kommunal särskild undervisningsgrupp, f d skoldaghem, och 3) ett HVB för utredning och behandling utan egen skola. Kännetecknande för dessa verksamheter är att de fått i uppdrag att fostra unga och att arbetet utförs i gränsområdet mellan undervisning och behandling. Vad händer i verksamheter som samtidigt ska åtgärda både sociala och pedagogiska problem och där diskurser från olika institutionella och vetenskapliga fält korsas? Genom att studera hur samhället hanterar unga som avskilts från den reguljära skolan syftar studien till att synliggöra hur olika diskurser om ”problembarn”, undervisning och behandling, skapar möjligheter och begränsningar för verksamheternas mål, medel och aktörer. Studiens metodologi är en kombination av etnografi och diskursanalys. Studien tar sin utgångspunkt i interaktion, vardag och identitetsformande processer. I dessa kommunikativa praktiker som är intimt relaterade till identitetsskapande, arbetar lärare och behandlare. Analys av vardagssituationer i dessa pedagogiska och sociala praktiker samt intervjuer av de unga och de anställda ger en ökad förståelse för vad som händer där och vad arbetet betyder för dess aktörer. Miljöerna består till stor del av informella mötesplatser där en flexibilitet i tolkningsmöjligheterna skapar förhandlingsutrymme om både vad som sker där, men också vilka de unga är. Användningen av informella miljöer, lekfullhet, kroppskontakt och humor upprätthåller konsensus och bygger relationer. Relationen möjliggör att de anställda kan skapa tillit och förtroende hos de unga och används för att stödja de unga och påverka dem i önskvärd riktning. Relationen innebär att de unga, samtidigt som de får stöd och omsorg, också kan kontrolleras. Två olika strategier, omsorg och kontroll, kopplas samman i vad Foucault beskriver som en pastoral maktutövning. Relationen är grunden för intersubjektivitet, d v s en delad kunskap om situationen och dem själva. Diskurserna som används utgår från att de unga ska förändras. Diskurserna tydliggör att de ungas förändring främst ses som avhängiga dem själva, men att förändring är sannolik och möjlig genom de ungas involvering. De unga själva ses i hög grad som ansvariga för att leva upp till de krav som samhället ställer på individer i den åldern. De anställda förväntas klara av fysisk gränssättning, använda tvångsåtgärder och hantera andra repressiva inslag. De ungas aktörskap synliggörs genom deras motstånd inför det som strider mot deras motiv och det som står på spel för dem, d v s deras normalitet. Intervjuer med de unga har sammanfattat de möjliga identitetsalternativ de unga uppfattar finns tillgängliga för dem och handlar om skapandet av vilka de varit och vilka de kan bli. Identiteterna beror på vilka tolkningsrepertoarer som används i de olika verksamheterna. Repertoarerna gör det möjligt att skapa olika identitetskonstruktioner där en del kan ses som mer normala än andra. En del av identitetsalternativen innebär att se sig själv som kriminell eller med brister av olika slag. Kamratkretsen på hemmaplan och som elev i skolan är den plats och det sammanhang där de unga känner sig mest som alla andra. / This study examines how society handles children who for different reasons can’t manage, or be managed, in compulsory schools. Observations and interviews were made in three different settings: 1) a foster home with its own school, 2) a small school for troubled youth, and 3) a home for assessment and treatment, without its own school. Common for these arenas are that the children have been separated and set apart from regular school, and they take place on the boundary, or in the intersection between, teaching and treatment. The aims are to reveal how different discourses about troubled youth, education and treatment create possibilities and limitations in relation to the goal of the practices targets, their means, and the actors. The study is based on research into interaction, daily life, and processes of identity transformation. The data is collected by ethnographic methods in the form of participant observations, and the analysis is informed by discourse analysis. In these communicative practices, educators and social workers were active in an area of research that is intimately related to identity. Analysis of everyday situations in pedagogical and social practices provides valuable knowledge for understanding what is going on in this practices and what the implications are for the actors. Examinations of the studied children’s environments and activities reveal the different emphases of efforts addressing the children’s needs which are informed by (connected to) the use of different discourses. The use of informal settings, playfulness, humour, and body contact help maintain consensus and build relationships. The relationships provide a basis for exerting influence. To offer support is also a means by which the young people can be controlled. Two strategies care and control are found to be linked in what Foucault describes as an exercise of pastoral power. These relationships are also the basis for intersubjectivity, that is, shared knowledge of the situation, including self-knowledge of the actors involved. The emphasis on informal environments and flexibility in interpreting the situation allows negotiation about who the children are and what they are expected to become. The balance in child welfare activities between coercion and free choice can be described as a balancing act in which employees have great responsibility for the children. The study discusses how different discourses affect young people’s identity. Considering the various working methods based on different discourses together with the specific child welfare activities suggests that there are several different ways to define the problem situation affecting the children; the children are in this way exposed to a number of troubled identities. The results also indicate that the children can refuse to make these identities their own. The children are actors who become visible through their resistance to what threatens their motives and through what is at stake for them, that is, their normality. Interviews with children have identified possible alternative identities that depend on repertoires of identities, in which some constructions are seen as more normal than others. The children prefer seeing themselves with friends at school and as pupils in school.

Syftet med denna studie är att visa hur skolorganisation, skolledning och skolledaridentiteter produceras, formas och omformas i samtalad interaktion samt att visa vilka diskursiva metoder som de samtalande använder för att bygga upp sina begrepp och kategorier och samtidigt göra dem socialt acceptabla i sitt sammanhang. Jag har tagit teoretisk och analytisk utgångspunkt i etnometodologi, socialkonstruktionism och kategoriseringsanalys. Det empiriska materialet består av inspelade ledningsgruppsmöten, som transkriberats noggrant, från en grundskola och två gymnasieskolor, samt intervjuer med tre skolledare. De empiriska studierna presenteras i fyra delstudier, där delstudie I visar hur intervjuare och intervjuad gemensamt bygger upp relevanta ategorier med hjälp av bland annat tidsbegrepp. I delstudie II analyseras hur skolledare i ett arbetslagsledarmöte gemensamt skapar den lokalt producerade organisationen-i-handling. Delstudie III fokuserar hur citeringar av sig själv och andra används i mötessamtal för att forma kategorier och delstudie IV inriktas mot att se hur deltagarna i de probleminriktade samtalen orienterar emot teamet och hur ’vi’ som grupp formas. I samtliga delstudier fokuseras hur kategoriserandet samtidigt är identitetsskapande. De samtalande framställer sig själva som bland annat problemlösare, nytänkare, förändrare och annorlunda än ’de andra’. Kategoriseringsarbete har visat sig ha stor betydelse för interaktionen och identitetsarbete är en viktig del av det som sker i mötessamtal. Skolledning framstår som bland annat gemensamt producerat och inte enbart som ett heroiskt ensamarbete. Tal och samtal kan beskrivas som en viktig del av och i ledningsarbetet. / The aim of this study is to show how school organization, school leadership and school leader identities are produced, formulated and transformed in talkin-interaction, and to show methods members use to build concepts and categories making them socially acceptable, in situ. My theoretical points of departure and analytical tools are ethnomethodology, social constructionism and membership categorization analysis. The empirical material consists of recorded talk sequences at regular meetings of school management teams, transcribed in detail, at one primary school and two secondary schools, and interviews with three assistant principals. The analysis of the empirical material is presented in four studies. tudy I shows how the interviewer and interviewee jointly construct relevant categories, using temporal terms as well as other resources. Study II analyzes how school leaders at a team meeting collectively create the organization-in-action. The focus of study III is on how team members use reported speech to produce categories, while study IV is oriented towards how we as a team is produced. All studies focus on categorization work as identity work. The team members and the interviewees give attributes to and make categorizations of themselves and others in order to produce themselves as problem-solvers, innovative, progressive and different. Categorization work has proven highly significant in the interaction, and identity work is an important component of the actions accomplished in the analyzed meetings. School leadership is not produced as a lone heroic effort, but rather as something created by members in interaction. Talk-in-interaction can be described as an important part of and in leadership work.

The patent domain is a very important source of scientific information that is currently not used to its full potential. Searching for relevant patents is a complex task because the number of existing patents is very high and grows quickly, patent text is extremely complicated, and standard vocabulary is not used consistently or doesn’t even exist. As a consequence, pure keyword searches often fail to return satisfying results in the patent domain. Major companies employ patent professionals who are able to search patents effectively, but even they have to invest a lot of time and effort into their search. Academic scientists on the other hand do not have access to such resources and therefore often do not search patents at all, but they risk missing up-to-date information that will not be published in scientific publications until much later, if it is published at all. Document search on PubMed, the pre-eminent database for biomedical literature, relies on the annotation of its documents with relevant terms from the Medical Subject Headings ontology (MeSH) for improving recall through query expansion. Similarly, professional patent searches expand beyond keywords by including class codes from various patent classification systems. However, classification-based searches can only be performed effectively if the user has very detailed knowledge of the system, which is usually not the case for academic scientists. Consequently, we investigated methods to automatically identify relevant classes that can then be suggested to the user to expand their query. Since every patent is assigned at least one class code, it should be possible for these assignments to be used in a similar way as the MeSH annotations in PubMed. In order to develop a system for this task, it is necessary to have a good understanding of the properties of both classification systems. In order to gain such knowledge, we perform an in-depth comparative analysis of MeSH and the main patent classification system, the International Patent Classification (IPC). We investigate the hierarchical structures as well as the properties of the terms/classes respectively, and we compare the assignment of IPC codes to patents with the annotation of PubMed documents with MeSH terms. Our analysis shows that the hierarchies are structurally similar, but terms and annotations differ significantly. The most important differences concern the considerably higher complexity of the IPC class definitions compared to MeSH terms and the far lower number of class assignments to the average patent compared to the number of MeSH terms assigned to PubMed documents. As a result of these differences, problems are caused both for unexperienced patent searchers and professionals. On the one hand, the complex term system makes it very difficult for members of the former group to find any IPC classes that are relevant for their search task. On the other hand, the low number of IPC classes per patent points to incomplete class assignments by the patent office, therefore limiting the recall of the classification-based searches that are frequently performed by the latter group. We approach these problems from two directions: First, by automatically assigning additional patent classes to make up for the missing assignments, and second, by automatically retrieving relevant keywords and classes that are proposed to the user so they can expand their initial search. For the automated assignment of additional patent classes, we adapt an approach to the patent domain that was successfully used for the assignment of MeSH terms to PubMed abstracts. Each document is assigned a set of IPC classes by a large set of binary Maximum-Entropy classifiers. Our evaluation shows good performance by individual classifiers (precision/recall between 0:84 and 0:90), making the retrieval of additional relevant documents for specific IPC classes feasible. The assignment of additional classes to specific documents is more problematic, since the precision of our classifiers is not high enough to avoid false positives. However, we propose filtering methods that can help solve this problem. For the guided patent search, we demonstrate various methods to expand a user’s initial query. Our methods use both keywords and class codes that the user enters to retrieve additional relevant keywords and classes that are then suggested to the user. These additional query components are extracted from different sources such as patent text, IPC definitions, external vocabularies and co-occurrence data. The suggested expansions can help unexperienced users refine their queries with relevant IPC classes, and professionals can compose their complete query faster and more easily. We also present GoPatents, a patent retrieval prototype that incorporates some of our proposals and makes faceted browsing of a patent corpus possible.

Workplace misbehaviour is seen to be a neglected feature of organizational study (Ackroyd and Thompson; Vardi and Weitz, 2004). Where research has been undertaken into misbehaviour the emphasis tends fall into two broad categories. First of all, organizational behaviour theorists use the term misbehaviour as a means to highlight how the ‘negative’ behaviour of employees gets in the way of formal organizational goals. Secondly, radical sociologists tend to use the term misbehaviour as a means to critique Foucauldian labour process theory. Here an argument is made that suggests the disciplinary affects of new management practices associated with human resource management and total quality management have been overstated. Furthermore, radical sociologists also use the term misbehaviour as means to critique organizational behaviour accounts, which are believed to paint overly optimistic accounts of organizational life. However, on further examination it was discovered that neither a radical sociological approach, nor a traditional organizational behaviour approach, sufficiently addresses the current deficit in our understandings and explanations for workplace misbehaviour. Hence, one of the main themes of this thesis was to design a theoretical and methodological framework to address the deficit in our understandings and explanations. As such, a view was taken of how a radical sociological approach (orthodox labour process analysis) combined with an emerging social psychological perspective (a social identity approach (Haslam, 2001)) could help overcome previous theoretical problems associated with researching misbehaviour. Empirical support for this approach is provided by the detailed examination of the objective and subjective working conditions of four different sets of low status workers. The findings are based on longitudinal covert participant observations, as well as covert interviews and the covert gathering of company documents. The findings depart from previous insights into workplace misbehaviour in stressing the importance of acknowledging and investigating both the organizational and sub-group social identities of low status workers, in relation to such activities. As such, a great deal of the misbehaviour noted in the findings can be attributed to the poor treatment of low status workers by management, yet misbehaviour is equally if not more attributable to the empowering or inhibitive qualities of the many psychological groups that worker can associate with or disassociate themselves from. Recommendations are made about the direction of future research into workplace misbehaviour. There are many suggestions made and include examining misbehaviour in a wider range of settings, sectors and levels of organizations.

En ésta tesis se estudian 2 aspectos de la toma decisiones. Primero, se investiga la forma en que las personas categorizan atributos numéricos. Se presenta y se prueba experimentalmente un modelo del proceso mental que usan las personas para trasformar una cantidad en una categoría verbal. Bajo ciertas condiciones situacionales, el modelo es capaz de predecir conceptualizaciones verbales. Segundo, se exploran las interconexiones entre la información cognitiva y emocional durante la decisión. Se elaboran y se prueban experimentalmente cuatro modelos de la forma en que se combina la información cognitiva y emocional durante el proceso de elección, para determinar el valor de una alternativa. Los modelos muestran una alta capacidad de predicción. Esta varía en función de (1) la interacción de la información verbal y numérica con la capacidad cognitiva situacional del individuo y (2) la correlación entre los juicios cognitivos y las reacciones emocionales. / The present dissertation investigates two aspects of decision making: First, I study the way in which people understand and categorize numerical attributes of products. I develop and experimentally test a model of the mental process people use to transform a quantitative attribute into a verbal category. Under certain environmental conditions, the model is able to predict the verbal conceptualization of people. Second, I explore the interconnections of cognitive and emotional information during the process of decision making. I propose and experimentally test four different models of the way cognitive and affective information is combined during the decision making process in order to determine the value of an alternative. The models display a high predictive power. Their performance is influenced by (1) the interaction of verbal and numerical information with the situational cognitive capacities of the individual and (2) by the correlation of cognitive judgments and affective reactions.

Esta tesis describe la variación conceptual en terminología. Entendemos por variación conceptual el proceso cognitivo que conduce a cambios graduales en un concepto y se manifiesta lingüística y semánticamente en grados diferentes de equivalencia entre los sentidos de una unidad léxica o entre los sentidos de sus variantes léxico-semánticas. Este estudio se basa en los fundamentos de la Teoría Comunicativa de la Terminología (TCT) (Cabré, 1999), en la teoría del término (Averboukh, 2005) y en la teoría de variación léxico-semántica (Karcevski, 1926 en Zviagintsev (ed.), 1965; Kury³owicz, 1955; Vinogradov, 1944; Smirnitsky, 1954; Ajmanova, 1957/2004; Nikitin 1974; Shmelev 1973/2008; Ufimtseva: 1986/2002; Solntsev, 1984, 1998, entre otros). Es un trabajo teórico, descriptivo y cualitativo que combina los postulados de la lingüística estructural y cognitiva y dos perspectivas del análisis del léxico: la semasiológica y la onomasiológica. La parte empírica de este estudio se basa en el método de estudio de casos e incluye el análisis de tres tipos de casos. En el caso A se comprueba que la situación prototípica de una acción nombrada por una unidad léxica nominal deverbal se proyecta en otros tipos de situaciones, conservando el Esquema nuclear o concepto básico. En el caso B se constata que una unidad léxica potencialmente polisémica actualiza diferentes significados y sentidos en el discurso especializado con dos tipos de relación entre ellos: intersección (polisemia irregular interdominio o intradominio) e inclusión (polisemia regular intradominio o interdominio). Se demuestra también que el comportamiento sintáctico y semántico del término en el discurso puede revelar pistas de la variación conceptual del mismo. Y en el caso C se demuestra que los expertos conceptualizan y categorizan sus objetos de estudio de maneras diversas, usando diversas estrategias cognitivas en los discursos que construyen. / This thesis describes conceptual variation in Terminology. By conceptual variation we understand the cognitive process leading up to gradual changes in a concept and which can be observed in different degrees of equivalence among senses of a lexical unit or among senses of the related lexical-semantic variants in discourse.This study is based on the Communicative Theory of Terminology (Cabré, 1999), the Theory of the Term (Averboukh, 2005), and the Theory of Lexical-Semantic Variation (Karcevski, 1926 in Zviagintsev (ed.), 1965; Kury³owicz, 1955; Vinogradov, 1944; Smirnitsky, 1954; Ajmanova, 1957/2004; Nikitin 1974; Shmelev 1973/2008; Ufimtseva: 1986/2002; Solntsev, 1984, 1998, etc.). It is a theoretical, descriptive, and qualitative study, which combines principles of Structural and Cognitive Linguistics and the semasiological and onomasiological perspectives of lexical analysis. The empirical part of the research consists of three cases following the case study methodology.In Case A, we see that the prototypical situation of an action named by a deverbal noun is mapped onto different kinds of situations preserving the Nuclear Scheme or basic concept. In Case B, it is proven that a potentially polysemic lexical unit activates various meanings and senses in specialized discourse, thus establishing two types of relations between them: intersection (inter- and intradomain irregular polysemy) and inclusion (inter- and intradomain regular polysemy). It is also demonstrated that the syntactic and semantic behaviour of terminological units in discourse can provide clues about conceptual variation. In Case C, it is confirmed that experts conceptualize and categorize their objects of study in different ways and construe their discourse using different cognitive strategies.

Over the past twenty years, the idea that planning and development practices should be ‘sustainable’ has become a key tenet of discourses characterising the field of planning and development. As part of the agenda to balance and integrate economic, environmental and social interests, democratic participatory governance arrangements are frequently purported to be necessary to achieve ‘sustainable development’ at both local and global levels. Despite the theoretical disjuncture between ideas of democratic civic participation, on the one hand, and civic participation as a means to achieve pre-determined sustainability goals on the other, notions of civic participation for sustainability have become integral features of sustainable development discourses. Underpinned by a conceptual and methodological intent to perform an epistemological ‘break’ with notions of civic participation for sustainability, this thesis explicates how citizens are enrolled in the sustainable development agenda in the discourse of policy. More specifically, it examines how assumptions about civic participation in sustainable development policy discourses operate, and unpacks some discursive strategies through which policy language ‘enrols’ citizens in the same set of assumptions around their normative requirement for participation in sustainable development. Focussing in on a case study sustainable development policy document – a draft regional plan representing a case of ‘enrolling the citizen in sustainability’ - it employs three sociological perspectives/methods that progressively highlight some of the ways that the policy language enjoins citizens as active participants in ‘sustainable’ regional planning. As a thesis-by-publication, the application of each perspective/method is reported in the form of an article prepared for publication in an academic journal. In a departure from common-sense understandings of civic participation for sustainability, the first article examines the governmentality of sustainable development policy. Specifically, this article explores how civic community – particularly community rights and responsibilities – are deployed in the policy discourse as techniques of government that shape and regulate the conduct of subjects. In this respect, rather than seeing civic community as a specific ‘thing’ and participation as corresponding to particular types of ‘activities’, this paper demonstrates how notions of civic participation are constructed and mobilised in the language of sustainable development policy in ways that facilitate government ‘at a distance’. The second article begs another kind of question of the policy – one concerned more specifically with how the everyday practices of subjects become aligned with the principles of sustainable development. This paper, therefore, investigates the role of pedagogy in establishing governance relations in which citizens are called to participate as part of the problematic of sustainability. The analysis suggests that viewing the case study policy in terms of relationships of informal pedagogy provided insights into the positioning of the citizen as an ‘acquirer’ of sustainability principles. In this instance, the pedagogic values of the text provide for low levels of discretion in how citizens could position themselves in the moral order of the discourse. This results in a strong injunction for citizens to subscribe to sustainability principles in a participatory spirit coupled with the requirement for citizens to delegate to the experts to carry out these principles. The third article represents a further breakdown of the ways in which citizens become enrolled in ‘sustainable’ regional planning within the language of the case study policy. Applying an ethnomethodological perspective, specifically Membership Categorization Analysis, this article examines the way ‘the citizen’ and ‘civic values and obligations’ are produced in the interactional context of the text. This study shows how the generation of a substantive moral order that ties the citizen to sustainable values and obligations with respect to the region, is underpinned by a normative morality associated with the production of orderliness in ‘text-in-interaction’. As such, it demonstrates how the production and positioning of ‘the citizen’ in relation to the institutional authors of the policy, and the region more generally, are practical accomplishments that orient the reader to identify him/herself as a ‘citizen’ and embrace the ‘civic values and obligations’ to which he/she is bound. Together, the different conceptual and methodological approaches applied in the thesis provide a more holistic picture of the different ways in which citizens are discursively enrolled in the sustainability agenda. At the substantive level, each analysis reveals a different dimension of how the active citizen is mobilised as a responsible agent for sustainable development. In this respect, civic participation for sustainability is actualised and reproduced through the realms of language, not necessarily through applied occasions of civic participation in the ‘taken-for-granted’ sense. Furthermore, at the conceptual and methodological level, the thesis makes a significant contribution to sociological inquiry into relationships of governance. Rather than residing within the boundaries of a specific sociological perspective, it shows how different approaches that would traditionally be applied in a mutually exclusive manner, can complement each other to advance understanding of how governance discourses operate. In this respect, it provides a rigorous conceptual and methodological platform for further investigations into how citizens become enrolled in programmes of government.

Η συγκεκριμένη διατριβή στοχεύει στον σχεδιασμό της μεθοδολογίας που θα εφαρμοστεί για την υλοποίηση ενός προσκομιστή πληροφορίας από τον Παγκόσμιο Ιστό, ο οποίος θα λειτουργεί λαμβάνοντας υπόψη θεματικά κριτήρια. Τέτοιου είδους προγράμματα ανίχνευσης πληροφορίας, είναι ευρέως γνωστά ως θεματικά εστιασμένοι προσκομιστές ιστοσελίδων. Κατά τη διάρκεια της μελέτης μας, σχεδιάσαμε και υλοποιήσαμε ένα καινοτόμο σύστημα θεματικής κατηγοριοποίησης ιστοσελίδων που κάνει εκτεταμένη χρήση των σημασιολογικών δεδομένων τα οποία περιέχονται στο σημασιολογικό δίκτυο WordNet. Η απόφαση για την αξιοποίηση του WordNet ελήφθη με τη φιλοδοξία να αντιμετωπιστούν αποτελεσματικά φαινόμενα ασάφειας εννοιών που μειώνουν τις επιδόσεις των διαθέσιμων θεματικών κατηγοριοποιητών. Η καταλληλότητα του WordNet για την επίλυση της σημασιολογικής ασάφειας έχει αποδειχθεί στο παρελθόν, αλλά ποτέ δεν εξετάστηκε σε ένα σύστημα εστιασμένης προσκόμισης ιστοσελίδων με τον συγκεκριμένο τρόπο, ενώ ποτέ δεν έχει αξιοποιηθεί στην κατηγοριοποίηση ιστοσελίδων για την ελληνική γλώσσα. Ως εκ τούτου, ο θεματικός κατηγοριοποιητής που υλοποιήσαμε, και κατά συνέπεια, και ο εστιασμένος προσκομιστής στον οποίο ενσωματώνεται ο κατηγοριοποιητής, είναι καινοτόμοι όσο αφορά τον τρόπο με τον οποίο αποσαφηνίζουν έννοιες λέξεων με στόχο την αποτελεσματική ανίχνευση του θεματικού προσανατολισμού μίας ιστοσελίδας . Ένας προσκομιστής ιστοσελίδων είναι ένα πρόγραμμα που με αφετηρία μία λίστα διευθύνσεων ιστοσελίδων (URLs) αρχικοποίησης προσκομίζει το περιεχόμενο των ιστοσελίδων που συναντά και συνεχίζει ακολουθώντας τους εσωτερικούς τους συνδέσμους με απώτερο σκοπό την προσκόμιση όσο το δυνατό μεγαλύτερου υποσυνόλου δεδομένων του Παγκόσμιου Ιστού (ανάλογα με τους διαθέσιμους πόρους, την χωρητικότητα του δικτύου, κλπ.). Δεδομένου ότι ο όγκος των δεδομένων που είναι διαθέσιμα στον Παγκόσμιο Ιστό αυξάνεται με εκθετικό ρυθμό, είναι πρακτικά αδύνατο να προσκομιστούν όλες οι ζητούμενες πηγές πληροφορίας ανά πάσα στιγμή. Ένας τρόπος για να αντιμετωπίσουμε το συγκεκριμένο πρόβλημα είναι η εκμετάλλευση συστημάτων εστιασμένης προσκόμισης ιστοσελίδων που στοχεύουν στη λήψη ιστοσελίδων συγκεκριμένης θεματολογίας που εκφράζουν κάθε φορά το θεματικό προφίλ του χρήστη, σε αντίθεση με τους προσκομιστές ιστοσελίδων γενικού σκοπού που καταναλώνουν πόρους άσκοπα προσπαθώντας να προσκομίσουν κάθε πιθανή πηγή πληροφορίας που συναντούν. Οι εστιασμένοι προσκομιστές χρησιμοποιούνται εκτενώς, για την κατασκευή θεματικά προσανατολισμένων ευρετηρίων ιστοσελίδων, κάθε ένα από τα οποία έχει την δυνατότητα να εξυπηρετήσει αιτήσεις χρηστών με συγκεκριμένο θεματικό προσανατολισμό. Με αυτό τον τρόπο είναι δυνατόν να αντιμετωπιστεί το πρόβλημα της υπερφόρτωσης πληροφοριών. Προκειμένου να επιτελέσουμε την συγκεκριμένη εργασία μελετήσαμε εκτενώς υπάρχουσες τεχνικές εστιασμένης προσκόμισης, στις οποίες στηριχθήκαμε ώστε να ορίσουμε την μεθοδολογία που θα ακολουθήσουμε. Το αποτέλεσμα είναι η υλοποίηση ενός θεματικά εστιασμένου πολυνηματικού προσκομιστή, ο οποίος ενσωματώνει τις εξής καινοτομίες: είναι ρυθμισμένος προκειμένου να εκτελεί εστιασμένες προσκομίσεις σε ιστοσελίδες ελληνικού ενδιαφέροντος, αποσαφηνίζει το κείμενο που αντιστοιχεί σε ιστοσελίδες προκειμένου να ανακαλύψει τον θεματικό τους προσανατολισμό. Επιπλέον προτείνουμε μία σειρά υποσυστημάτων τα οποία θα μπορούσαν να ενσωματωθούν στο σύστημα εστιασμένης προσκόμισης προκειμένου να ενισχύσουμε την απόδοσή του. Τέτοια συστήματα είναι το υποσύστημα ανίχνευσης όψεων που αντιστοιχίζονται σε επώνυμες οντότητες καθώς και το υποσύστημα εξαγωγής λέξεων κλειδιών που μπορούν να χρησιμοποιηθούν ως χαρακτηριστικά κατηγοριοποίσης από το αλφαριθμητικό των διευθύνσεων (URL) ιστοσελίδων. Για να παρουσιάσουμε την αποτελεσματικότητα της προτεινόμενης μεθόδου, διενεργήσαμε μία σειρά πειραματικών μετρήσεων. Συγκεκριμένα αξιολογήσαμε πειραματικά τα ακόλουθα: την αποτελεσματικότητα του αλγορίθμου αποσαφήνισης που ενσωματώσαμε στον προσκομιστή, την απόδοση του θεματικού κατηγοριοποιητή ο οποίος καθορίζει την συμπεριφορά του εστιασμένου προσκομιστή σχετικά με το αν μια σελίδα θα πρέπει να κατέβει ως θεματικά σχετική με το θέμα ενδιαφέροντος ή όχι, την απόδοση του εστιασμένου προσκομιστή καταγράφοντας τον ρυθμό απόκτησης που επιτυγχάνει κατά την διάρκεια της εστιασμένης προσκόμισης χρησιμοποιώντας κάθε φορά διαφορετικά χαρακτηριστικά κατηγοριοποίησης, την καταλληλότητα του υποσυστήματος εξαγωγής λέξεων-κλειδιών από το αλφαριθμητικό URL για την περιγραφή του θεματικού προσανατολισμού της ιστοσελίδας και τέλος τη χρησιμότητα του συστήματος αναγνώρισης επώνυμων οντοτήτων στην οργάνωση ιστοσελίδων των οποίων η σημασιολογία δεν αναπαρίσταται ικανοποιητικά σε σημασιολογικούς πόρους γενικού σκοπού συμπεριλαμβανομένου του σημασιολογικού δικτύου WordNet. Τα πειραματικά αποτελέσματα επιβεβαιώνουν τη συμβολή του θεματικά εστιασμένου προσκομιστή που προτείνουμε στην προσκόμιση περιεχομένου ειδικού ενδιαφέροντος από τον Παγκόσμιο Ιστό. Παράλληλα αποδεικνύουμε ότι όλες οι μέθοδοι που ενσωματώσαμε στο σύστημα εστιασμένης προσκόμισης είναι δυνατό να συνεργαστούν κατά τρόπο που να βελτιώνει την απόδοση του προσκομιστή . Τέλος από τα πειραματικά αποτελέσματα αποδεικνύεται ότι η προτεινόμενη τεχνική είναι εξίσου αποτελεσματική για ιστοσελίδες στα αγγλικά και στα ελληνικά. Επιπλέον πιστεύουμε ότι μπορεί να εφαρμοστεί με επιτυχία και σε ιστοσελίδες που περιέχουν κείμενα άλλων φυσικών γλωσσών, με προϋπόθεση την ύπαρξη σημασιολογικών πόρων, αντίστοιχων με το WordNet και διαθέσιμων εργαλείων που θα επιτρέπουν την ανάλυση των δεδομένων κειμένου τους. / This dissertation aims at the specification of an algorithmic methodology that will be applied towards the implementation of a web crawler, which will operate upon thematic criteria. Such crawlers are widely known as topical focused web crawlers. To realize our objective, the utilization of a web page thematic classification system (either existing or newly developed one) is imperative. In the course of our study, we designed and implemented a novel thematic classifier that makes extensive use of the semantic data encoded in WordNet semantic network and such decision was taken with the aspiration of tackling effectively sense ambiguity phenomena that degrade the performance of available classifiers. The suitability of WordNet towards resolving semantic ambiguity has been previously proven but never examined in a focused web crawling application and has never been exploited for the Greek language. Therefore, our thematic classifier and consequently our focused crawler that integrates it are innovative in the way in which they perform word sense disambiguation for achieving the effective detection of the web page topics (themes). In a broad sense, a web crawler is a program that based on a seed list of URLs it downloads the contents of the web pages it comes across and continues following their internal links with the utmost objective of fetching as much as web data as possible (depending on available resources, network capacity, etc.). Given that the web data grows at exponential rates, it is practically impossible to download all the web sources at any given time. One way to tackle such difficulty is to implement and employ topical focused crawlers that aim at downloading content of specific topics (potentially of interest to the user) rather than waste resources trying to download every single data source that is available on the web. Topically focused crawlers are extensively used for building topical focused indices, each of which can serve specialized user search requests, therefore dealing partially with the information overload problem. To carry out our work, we have extensively reviewed existing approaches with respect to topically focused crawling techniques upon which we relied for defining our own focused crawling methodology, which resulted into the implementation of a topical focused crawler that incorporates the following innovate features: it is tailored to operate on the Greek web, it disambiguates the web pages in order to uncover their topic and it incorporates numerous features, such as a named entities recognizer, a URL keyword extractor, personalization techniques, etc., in order to maximize its performance. To demonstrate the effectiveness of our method, we have applied our topical focused crawler on several datasets and experimentally evaluated the following issues: the efficiency of the sense resolution algorithm incorporated into our crawler, the performance of the topical classifier that the crawler consults prior to making a final decision as to whether a page should be downloaded as topically relevant to a subject of interest or not, the suitability of the URL keyword extractor module for judging the subject of a web page based entirely on the analysis of its URL, the usefulness of the named entities recognizer in organizing pages whose semantics are poorly represented within the contents of general-purpose semantic resources (including WordNet semantic network). Experimental results confirm the contribution of our topically focused crawler in downloading web content of specific interest and show that all the methods and techniques that we have successfully integrated into the crawler can interoperate with its other in a manner that improves the crawling performance while allowing for flexibility in the downloading process at the same time. Last but not least, experimental results showcase that our crawling methodology is equally effective for both English and Greek and we believe that it can be fruitfully applied to other natural languages provided that there the respective semantic resources and tools are available for analyzing their textual data.