<p>I detta arbete undersöks hur kryptering påverkar prestandan hos en XML-databas. Detta görs med hjälp av ett inom litteraturen populärt dataset, XMark. Kryptering genomförs med hjälp av standarden XML Encryption. Okrypterade dataset jämförs med krypterade dataset genom att ställa Xpath-frågor och mäta tiden för dessa frågeställningar. Resultaten presenteras i tabeller och grafer och analyseras utifrån ett prestandaperspektiv. Även framtida utökning av testerna föreslås som framtida arbete.</p>

<p>Behovet av datautbyte mellan olika system, ökar ständigt. Därför byggs fler och fler system med möjligheten att utbyta och överföra data via XML. Då olika system lagrar data på olika sätt, måste de strukturella och innehållsmässiga skillnaderna hanteras innan data kan överföras.</p><p>Syftet med detta arbete är att undersöka hur dataöverföringar mellan XML-dokument i flera steg påverkas av strukturella eller innehållsmässiga skillnader. Arbetet visar i vilka fall data inte kan överföras korrekt. Studien utförs genom en experimentell metod. Experimenten genomförs med en applikation som utvecklats för ändamålet.</p><p>Resultatet från studien visar att problem kan uppstår då käll- och målstrukturen lagrar ett element eller attribut med olika datatyper, de övriga strukturmässiga skillnaderna genererar få problem. De innehållsmässiga skillnaderna medför att data inte kan identifieras då attributet saknas i käll- eller målstrukturen.</p>

Η ολοένα αυξανόμενη διείσδυση και χρήση του Internet παγκοσμίως έχει οδηγήσει στην επιτακτική ανάγκη ενός καλά ορισμένου και κοινά αποδεκτού τρόπου αναπαράστασης και ανταλλαγής της πληροφορίας στο διαδίκτυο. Όλο και περισσότερα ετερογενή συστήματα και πλατφόρμες χρειάζονται να ανταλλάξουν δεδομένα και πληροφορίες μεταξύ τους, με τρόπο καλά ορισμένο αλλά ταυτόχρονα δυναμικό και ελαστικό. H XML αναπτύχθηκε για να επιλύσει ακριβώς αυτό το πρόβλημα, της εινιαίας και καθολικά αποδεκτής αναπαράστασης της διακινούμενης πληροφορίας. Η ραγδαία αύξηση όμως του όγκου των δεδομένων που αναπαρίστανται σε XML δημιούργησε την ανάγκη αναζήτησης μέσα στην δενδρική δομή ενός ΧΜL εγγράφου για κάποια συγκεκριμένη πληροφορία. Η ανάγκη αυτή ταυτόχρονα με την ανάγκη για γρήγορη πρόσβαση στους κόμβους του ΧΜL δέντρου, οδήγησε σε διάφορα εξειδικευμένα ευρετήρια καθένα με διαφορετικά χαρακτηριστικά και δομή. Τα δεδομένα όμως στη σύγχρονη κοινωνία της πληροφόρησης δεν παραμένουν στατικά, αλλά διαρκώς αλλάζουν και μεταβάλλονται δυναμικά. Για να μπορέσουν να αναταποκριθούν στη δυναμική αυτή των δεδομένων, τα ευρετήρια θα πρέπει να έχουν τη δυνατότητα να μεταβάλλονται και αυτά δυναμικά και με ελάχιστο κόστος. Ταυτόχρονα με την ανάγκη αναζήτησης συγκεκριμένης πληροφορίας μέσα σε ένα σύνολο XML δεδομένων, γεννήθηκε και η ακριβώς αντίστροφη ανάγκη: το φιλτράρισμα ενός συνόλου XML δεδομένων διαμέσου κάποιων προτύπων και κανόνων ώστε να βρεθούν εκείνα τα δεδομένα που ταιριάζουν με τα αποθηκευμένα πρότυπα και κανόνες. Το πρόβλημα αυτό συναντάται κυρίως στα συστήματα publish/subscribe, στα οποία οι χρήστες ορίζουν τα ενδιαφέροντά τους και το σύστημα αναλαμβάνει να τους αποστέλλει μόνο πληροφορίες και δεδομένα σχετικά με τις προτιμήσεις τους. Η αναπαράσταση της πληροφορίας σε XML οδήγησε τα συστήματα αυτά να ενσωματώσουν αλγορίθμους φιλτραρίσματος των XML δεδομένων διαμέσου ενός συνόλου προτύπων και κανόνων που έχουν ορίσει εκ των προτέρων οι χρήστες του. Στα πλαίσια της μεταπτυχιακής αυτής εργασίας μελετάμε και συγκρίνουμε τις υπάρχουσες τεχνικές δυναμικής δεικτοδότησης και φιλτραρίσματος XML εγγράφων και παρουσιάζουμε έναν νέο, πρωτοποριακό αλγόριθμο φιλτραρίσματος που υπερτερεί των υπαρχόντων. / The increasingly use of Internet worldwide has led to the impulsory need of a standard, well-defined and wide-accepted information representation. More and more heterogeneous systems require exchanging data and information between them, in a well-defined, flexible and dynamic matter. XML was created in order to address the need of a standard and well-defined information representation. However, the boom of information capacity expressed in XML has rised a new problem: that of searching among a huge XML data for a specific information. This problem along with the need of efficient access to the nodes of an XML tree-structured document has led to the proposal of various heuristic indexes, each one with diferrent structure and features. However, because data do not remain static but change dynamically through time, the proposed indexes should have the flexibility to change dynamically accordingly to the data changes, with the minimal cost. Together with the problem of searching through a set of XML documents, a new problem has rised: that of filtering an XML document through a predefined set of patterns and rules. This problem comes from publish/subscribe systems where the users define their interests and preferences and the system undertakes to filter incoming information through the stored user profiles. The vast volume of XML-represented data and information has led those systems to incorporate XML filtering algorithms which filter the incoming XML data streams through the predefined user profiles.

Sistemos veikimo logika – mazgo pasirinkimo semantika, pasinaudojant sukurtais dokumentų standartais aprašytais XML kalba (DTD, XSD). Problema iškyla, kai kuriant dinaminių dokumentų analizės įrankius laikomasi griežtų taisyklių, tai reiškia negalima sulaužyti statinio tipo dokumento struktūros ir jo logikos. Problemos sprendimui yra panaudojama XPath technologija. Tokiu būdų yra sukuriamos statinio tipo užklausos ir išrenkamas dokumentų turinys, kuris vėliau atvaizduojamas vartotojo ekrane. Pagrindinis darbas yra sukurti įrankį, kurio pagalba galima atlikti statinę dokumento analizę. Dokumento duomenimis galima migruoti į pasirinktą reliacinę duomenų bazę ar kitą pasirinktą (PDF, XSL) dokumento formatą. Tokie įrankiai - analizatoriai leidžia sutaupyti daug laiko apdorojant, išrenkant, išsaugant ir analizuojant turimus duomenis. / Nowadays, there is a lot of information in the internet, personal computer, mobile phone and everywhere around us. How we exchange this information? There are many decisions, but the most popular exchange form is using XML document standards. What is more, it will be everything good, but people are, who wants to use them, often faced with certain problems. They are trying get this information from these documents, but they cannot read it or very hard without any special software. Some people do not trust XML documents, because they didn’t use any time of them. Where is the problem? Some people could not understand XML document methodology; others did not use special software for special XML documents. It is software for storing and migrating signed XML documents. Special tools can save us time. People can quickly access the documents and information they need. It can help people work together in ways that are most effective for them.

No description available.

This thesis investigates the usage area of Extensible Markup Language Message Text Format (XML-MTF) in Tactical Command and Control Information System (TC2IS). It examines the used tactical message types and their application area in Turkish Army and what the XML and XML-MTFs are explained. Finally / MTF traffic of a brigade is simulated to verify that XML technology can be used effectively in Turkish Land Forces Tactical Command Control and Information System Projects (TLF TC2IS).

Real-world information containing subjective opinions and judgments has emerged the need to represent complex and imprecise data in databases. Additionally, the challenge of transferring information between databases whose data storage methods are not compatible has been an important research topic. Extensible Markup Language (XML) has the potential to meet these challenges since it has the ability to represent complex and imprecise data. In this thesis, an XML based fuzzy data representation and querying system is designed and implemented. The resulting system enables fuzzy querying on XML documents by using XQuery, a language used for querying XML documents. In the system, complex and imprecise data are represented using XML combined with the fuzzy representation. In addition to fuzzy querying, the system enables restructuring of XML Schemas by merging of elements of the XML documents. By using this feature of the system, one can generate a new XML Schema and new XML documents from the existing documents according to this new XML Schema. XML data used in the system are retrieved from Internet by Web Services, which can make use of XML&rsquo / s capabilities to transfer data and, XML documents are stored in a native XML database management system.

Konstanz, Univ., Diplomarb., 2003.

O objetivo geral desta tese é a detecção, o gerenciamento e a consulta às réplicas e às versões de documentos XML. Denota-se por réplica uma cópia idêntica de um objeto do mundo real, enquanto versão é uma representação diferente, mas muito similar, deste objeto. Trabalhos prévios focam em gerenciamento e consulta a versões conhecidas, e não no problema da detecção de que dois ou mais objetos, aparentemente distintos, são variações (versões) do mesmo objeto. No entanto, o problema da detecção é crítico e pode ser observado em diversos cenários, tais como detecção de plágio, ranking de páginas Web, identificação de clones de software e busca em sistemas peer-to-peer (P2P). Nesta tese assume-se que podem existir diversas réplicas de um documento XML. Documentos XML também podem ser modificados ao longo do tempo, ocasionando o surgimento de versões. A detecção de réplicas é relativamente simples e pode ser feita através do uso de funções hash. Já a detecção de versões engloba conceitos de similaridade, a qual pode ser medida por várias métricas, tais como similaridade de conteúdo, de estrutura, de assunto, etc. Além da análise da similaridade entre os arquivos também se faz necessária a definição de um mecanismo de detecção de versões. O mecanismo deve possibilitar o gerenciamento e a posterior consulta às réplicas e às versões detectadas. Para que o objetivo da tese fosse alcançado foram definidos um conjunto de funções de similaridade para arquivos XML e o mecanismo de detecção de réplicas e de versões. Também foi especificado um framework onde tal mecanismo pode ser inserido e os seus respectivos componentes, que possibilitam o gerenciamento e a consulta às réplicas e às versões detectadas. Foi realizado um conjunto de experimentos que validam o mecanismo proposto juntamente com a implementação de protótipos que demonstram a eficácia dos componentes do framework. Como diferencial desta tese, o problema de detecção de versões é tratado como um problema de classificação, para o qual o uso de limiares não é necessário. Esta abordagem é alcançada pelo uso da técnica baseada em classificadores Naïve Bayesianos. Resultados demonstram a boa qualidade obtida com o mecanismo proposto na tese. / The overall goals of this thesis are the detection, management and querying of replicas and versions of XML documents. We denote by replica an identical copy of a real-world object, and by version a different but very similar representation of this object. Previous works focus on version management and querying rather than version detection. However, the version detection problem is critical in many scenarios, such as plagiarism detection, Web page ranking, software clone identification, and peer-to-peer (P2P) searching. In this thesis, we assume the existence of several replicas of a XML document. XML documents can be modified over time, causing the creation of versions. Replica detection is relatively simple and can be achieved by using hash functions. The version detection uses similarity concepts, which can be assessed by some metrics such as content similariy, structure similarity, subject similarity, and so on. Besides the similarity analysis among files, it is also necessary to define the version detection mechanism. The mechanism should allow the management and the querying of the detected replicas and versions. In order to achieve the goals of the thesis, we defined a set of similarity functions for XML files, the replica and version detection mechanism, the framework where such mechanism can be included and its components that allow managing and querying the detected replicas and versions. We performed a set of experiments for evaluating the proposed mechanism and we implemented tool prototypes that demonstrate the accuracy of some framework components. As the main distinguishing point, this thesis considers the version detection problem as a classification problem, for which the use of thresholds is not necessary. This approach is achieved by using Naïve Bayesian classifiers.

Assim como as aplicações, as bases de dados evoluem ao longo do tempo. Esta evolução ocorre em função de alterações de cunho técnico ou por alterações na realidade modelada pela base de dados. Bases de dados semiestruturados, compostas por esquemas e documentos XML, são afetadas por esta evolução de uma maneira diversa daquela observada em bases de dados relacionais. Modificações em esquemas podem levar bases de dados semiestruturados a um estado inconsistente, pois as instâncias podem tornar-se incompatíveis com as definições mais recentes dos esquemas. Em bancos de dados relacionais, modificações que levem a base a um estado inválido são bloqueadas pelo sistema gerenciador. Em bases de dados semiestruturados sem um sistema gerenciador, modificações no esquema não podem ser bloqueadas em função das instâncias existentes, em função da ausência do gerenciador. Trabalhos acadêmicos e comerciais na área de evolução de esquemas XML modelam diferentes aspectos deste processo, mas usualmente não abordam o efeito que a evolução do esquema possui sobre as instâncias existentes. As soluções propostas para este problema usualmente demandam intervenção do administrador do banco de dados na adaptação das instâncias ou a utilização de uma interface específica para edição do esquema. Este trabalho especifica o X-Spread, um mecanismo automático para propagação de modificações em esquemas para documentos XML. O X-Spread monitora periodicamente esquemas XML, e ao identificar modificações em um esquema, inicia a revalidação dos documentos que referenciam o esquema modificado. A revalidação analisa somente as porções dos documentos correspondentes às porções modificadas no esquema. Documentos considerados inválidos no processo de revalidação serão submetidos ao processo de adaptação, a fim de tornarem-se novamente compatíveis com as definições do esquema. A arquitetura proposta para o X-Spread permite o seu emprego em diferentes cenários de utilização de bases de dados semiestruturados. A mesma arquitetura proposta para revalidação e adaptação de documentos XML é aplicável a mensagens XML trocadas entre aplicações através de uma rede de dados. Ao administrador do banco de dados semiestruturado é oferecida a flexibilidade de utilização de qualquer ferramenta desejada para edição do esquema, bem como a possibilidade de restringir conforme suas necessidades o conjunto de operações de revalidação e adaptação executadas pelo X-Spread. A principal contribuição do X-Spread é a modelagem de todas as fases do processo de evolução de esquemas e dos processos de revalidação e adaptação de documentos XML. O processos definidos aplicam-se a documentos armazenados em um servidor de arquivos e a documentos transmitidos entre diferentes aplicações através de uma rede de dados. / Like applications, databases evolve as time goes by. Evolution can occur due to technical changes or due to changes in the modeled reality. Semistructured databases, composed by schema and XML documents, are not affected by evolution as relational databases. Changes to semistructured schema can lead the database to an inconsistent state, since instances can become invalid with respect to the most recent schema definitions. Modifications that lead the database to an inconsistent state are blocked by the management system of relational databases. Semistructured databases with no management system can not have this kind of modification blocked due to the lack of management system. Academic and commercial research on XML schema evolution models different evolution aspects, but usually the effect that evolution has on existing database instances is not investigaed. When this effect is subject of investigation, the proposed solutions usually require database administrator intervention in the instance adaptation process or usage of an specific schema update interface. This work specifies X-Spread, an automatic mechanism for propagation of schema modification to XML documents. X-Spread periodically monitors XML schemata, and upon identification of changes, revalidation of documents with references to the changed schema is started. Revalidation takes into account only items in the document equivalent to items modified in the schema. Documents considered invalid during the revalidation process are subjected to the adaptation process, in order to become once again valid with respect to the schema. The X-Spread architecture supports different scenarios of semistructured databases usage. This architecture can also be used for revalidation and adaptation of XML messages exchanged by applications over a network. To the database administrator is offered the flexibility of choice on schema edit tool, as well as the ability to restrict the set of operations executed by X-Spread during the revalidation and adaptation processes. The main contribution of X-Spread is the modeling of all schema evolution phases as well as the XML document revalidation and adaptation processes modeling. These processes here defined are suitable to XML documents stored in a file server as well as XML messages exchanged by application over a network.