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Thesis (M.Sc.)--York University, 2005. Graduate Programme in Computer Science and Engineering. / Typescript. Includes bibliographical references (leaves 113-117). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss &rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR11840

Λαμβάνοντας υπόψη ότι η χρήση των υπολογιστών μεταφέρθηκε από τους ερευνητικούς οργανισμούς στις επιχειρήσεις, διαπιστώνουμε ότι αποτελεί πλέον αναπόσπαστο επιχειρηματικό εργαλείο. Φτάνοντας στις αρχές της δεκαετίας του ‘90, μεγάλοι επιχειρηματικοί και κρατικοί φορείς διέθεταν τεράστιες ποσότητες δεδομένων που θα έπρεπε να εκμεταλλευθούν. Τα παραπάνω σε συνδυασμό με την εδραιωμένη πλέον αντίληψη ότι η πληροφορία αποτελεί το πιο πολύτιμο αγαθό, οδήγησαν στην ανάγκη για εφαρμογές ανάλυσης και επεξεργασίας μεγάλου όγκου δεδομένων. Την λύση δίνουν οι τεχνολογίες των Αποθηκών Δεδομένων (Data warehouses) και της αναλυτικής Επεξεργασίας Δεδομένων (OLAP). Τον τελευταίο καιρό διεξάγεται σημαντική έρευνα σε οντολογίες και σημασιολογικά δίκτυα, όπου πλέον η πληροφορία περιγράφεται εννοιολογικά για να είναι ευκολότερη η ανάκτηση της, η χρησιμοποίηση της και η σύγκριση της, δημιουργείται η ανάγκη εύρεσης ενός νέου συνδυαστικού τρόπου αναπαράστασης της γνώσης. Στην παρούσα διπλωματική εργασία ο αναγνώστης εισάγεται στα σημασιολογικά δίκτυα. Εκεί παρουσιάζονται αναλυτικά τα είδη των σημασιολογικών δικτύων και ιδιαίτερα ορισμένα που χρησιμοποιούνται για την αντιμετώπιση εξαιρέσεων. Δίνετε εισαγωγική περιγραφή της θεωρίας που αναπτύσσεται στις βάσεις δεδομένων με ιδιαίτερη έμφαση στις πολυδιάστατες βάσεις και τις αποθήκες δεδομένων. Παρουσιάζονται αναλυτικά τα OLAP εργαλεία καθώς και οι βασικές έννοιες που τα αποτελούν. Τέλος, γίνεται η παρουσίαση μιας νέας τεχνικής που βασίζεται στις μεθόδους αντιμετώπισης εξαιρέσεων σε ένα σημασιολογικό δίκτυο με σκοπό να επεκτείνει ένα OLAP μοντέλο και να το καταστήσει ικανό να αντιμετωπίσει εξαιρέσεις. Η προτεινόμενη επέκταση επιτρέπει την ύπαρξη εξαιρέσεων μεταξύ των τιμών των διαστάσεων ενός υπερκύβου δεδομένων, οι οποίες παίζουν σημαντικό ρόλο στην σωστή εξαγωγή συμπερασμάτων. / Taking into consideration that the use of computers has been transferred from research institutes to private companies and industries, we found out that computers constitute henceforth an integral enterprising tool. During the early 90’s, large private and public institutions afforded enormous quantities of data which revealed the need to be exploited. According to the above and having in mind that standing concepts handle information as the most important asset, it is noted that there is a need for applications that analyse and handle large amount of data. A solution to this problem was given by the data warehouse technologies and the analytical data processing (OLAP). Recently considerable research is conducted on ontologies and semantic networks, where information is already described in a conceptual way, which makes it easier to recover, to use it and compare to other similar. Thus, it is created the need of finding a new combination method of representation of knowledge. In the present master’s dissertation the reader is introduced into semantic networks. All the types of certain semantic networks are presented in detail and particularly those which are dealing with the representation of exceptions. Emphasis is given to the case of multidimensional databases as well as data deposits. Among them, OLAP tools and their basic theory is being described in more analysis. Finally, there is a presentation of a new technique that is based on methods for encountering exceptions in a semantic network whose goal is to extend one OLAP model in order to enable exception overcoming. The proposed expansion allows the existence of exceptions among the dimension values of a data hypercube which play a significant role to the right export of results.

This dissertation thesis is focused on bulk unsolicited messages which are present in current time in all sectors of electronic communications. It is not only e-mail communication, but also in online forums, discussion contributions, social networking and more. Analyze spam messages is therefore an essential element in preventing flooding user mailboxes. Antispam countermeasures is a set of processes, software tools and methods. It is necessary to harmonize all these components into one cooperating piece of service. Administrators of email servers are trying to keep their servers optimally configured. The problem is that spammers trying continuously these defense mechanisms and filter bypass to enhance spam processes. Their work is very sophisticated and this fight does not yet have a clear winner. After enhancement techniques either processes takes place after a certain time to balance the advantages and disadvantages. For these reasons it is necessary to have a tool which can be analyzed in depth junk messages with dynamic data views. This tool can be Online Analytical Processing (OLAP below), which is very suitable for this purpose. Presented a method of data extraction and transformation and preparation for storage in a warehouse DT-MEZ (Data Pump - metadata email messages). This method is part of the methodology ASOLAP (Antispam - OLAP).

No description available.

Made available in DSpace on 2014-06-12T15:59:54Z (GMT). No. of bitstreams: 2 arquivo5705_1.pdf: 963823 bytes, checksum: 471ae4b6b6c49b8c08bc92915c2f412b (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2006 / Algumas tecnologias têm se mostrado promissoras como meios de auxiliar na tomada de decisões estratégicas, destacando-se Sistemas de Informação Geográfica(SIG), Data Warehouses( DW) e On-Line Analytical Processing(OLAP), que constituem mecanismos úteis para suporte à decisão e normalmente atuam de forma independente. Devido à natureza diversificada das informações, uma abordagem unindo as funcionalidades presentes em cada ambiente aponta como uma solução mais adequada ao cenário atual, resultando numa poderosa ferramenta para análise dos dados ao considerar simultaneamente características presentes nos dados analíticos e aspectos específicos dos dados geográficos. O presente trabalho demonstrou que as limitações tecnológicas existentes pelo fato de não haver uma linguagem de consulta única, que permita o uso de operações geográficomultidimensionais para acessar um Data Warehouse Geográfico, podem ser superadas. Através da união de linguagens de consulta distintas e que operam individualmente, ele permitiu a realização do processamento geográfico-multidimensional. Para lidar com este contexto, os algoritmos Restrição Multidimensional-Geográfica e Restrição Geográfico-Multidimensional foram propostos e validados. Um engenho para processamento geográfico-multidimensional que implementava estes algoritmos foi desenvolvido a partir de extensões de ferramentas disponibilizadas como Software Livre. Também foi elaborado um protótipo com interface web que estendia uma ferramenta OLAP existente e incorporava a possibilidade de executar consultas geográfico-multidimensionais de mapeamento, permitindo assim a visualização dos resultados das requisições de forma tabular, gráfica ou através de mapas. Por fim, um DWG com dados sobre o sistema público de saúde brasileiro foi construído e utilizado como base em uma análise estatística conduzida para verificar qual, dentre os dois algoritmos propostos e considerando as situações em que eles produzem o mesmo resultado, tinha melhor desempenho. A avaliação experimental mostrou que o algoritmo Restrição Geográfico-Multidimensional é o mais indicado, visto que apresentou melhor desempenho em situações consideradas mais realistas para consultas a um DWG