published_or_final_version / abstract / Mathematics / Doctoral / Doctor of Philosophy

published_or_final_version / Computer Science / Doctoral / Doctor of Philosophy

published_or_final_version / Architecture / Doctoral / Doctor of Philosophy

published_or_final_version / Public Health / Master / Master of Public Health

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

Data integration systems provide uniform access to a set of heterogeneous structured data sources. An essential component of a data integration system is the mapping between the federated data model and each data source. The scale of interconnect among data sources in the big data era is a new impetus for automating the mapping process. Despite decades of research on data integration, generating mappings still requires extensive labor. The thesis of this research is that the progress on automatic data integration has been limited by a narrow definition of mapping. The common mapping process is to find correspondences between pairs of entities in the data models, and create logic expressions over the correspondences as executable mappings. This does not cover all issues in real world applications. This research aims to overcome this problem in two ways: (1) generalize the common mapping definition for relational databases; (2) address the problem in a more general framework, the Semantic Web. The Semantic Web provides flexible graph based data models and reasoning capabilities as in knowledge representation systems. The new graph data model introduces opportunities for new mapping definitions. The comparison of mapping definitions and solutions for both relational databases and the Semantic Web is discussed. In this dissertation, I propose two generalizations of mapping problems. First, the common schema matching definition for relational databases is generalized from finding correspondences between pairs of attributes to finding correspondences consisting of relations, attributes, and data values. This generalization solves real world issues that are not previously covered. The same generalization can be applied to ontology matching in the Semantic Web. The second piece of work generalizes the ontology mapping definition from finding correspondences between pairs of entities to pairs of graph paths (sequences of entities). As a path provides more context than a single entity, mapping between paths can solve two challenges in data integration: the missing mapping challenge and the ambiguous mapping challenge. Combining the two proposed generalizations together, I demonstrate a complete data integration system using the Semantic Web techniques. The complete system includes the components of automatic ontology mapping and query reformulation, and semi-automatically federates the query results from multiple data sources. / text

Open access to health data can bring enormous social and economical benefits. However, such access can also lead to privacy breaches, which may result in discrimination in insurance and employment markets. Privacy is a subjective and contextual concept, thus it should be interpreted from both systemic and information perspectives to clearly understand potential breaches and consequences. This dissertation investigates three popular use cases of healthcare data: specifically, 1) synthetic data publication, 2) aggregate data utilization, and 3) privacy-aware API implementation. For each case, we develop statistical models that improve the privacy-utility Pareto frontier by leveraging a variety of machine learning techniques such as information theoretic privacy measures, Bayesian graphical models, non-parametric modeling, and low-rank factorization techniques. It shows that much utility can be extracted from health records while maintaining strong privacy guarantees and protection of sensitive health information. / text

The establishment of copyright protection systems aims to achieve two important purposes; to stimulate the incentive for creation by granting authors a series of exclusive rights on the one hand, and promote the progress of culture and public welfare by establishing a series of limitations on these exclusive rights so that the flow of information and dissemination of knowledge will not be hindered on the other hand. There is always a close relationship between technology development and copyright law. The emergence of personal computers and the internet has brought about a distinct wave of technological innovation that has reshaped copyright laws by empowering anyone with a connection to flawless, inexpensive and instantaneous reproduction and distribution of works of authorship. Such technological advancement changes the interests of copyright owners and public users. Users are exposed to more opportunities brought about by digital network technology to obtain access and exploit copyrightable works. If copyright laws do not expand their protected subject matters and categories of exclusive rights, authors cannot be adequately compensated under the digital network environment. Copyright laws can no longer function as an incentive for creation if there is a lack of revision and appropriate expansion. Hence, copyright laws need to extend protection to new subject matters, such as computer programs and databases; grant right holders new kinds of rights, such as right of rental and right to network dissemination of information; establish indirect infringing liability for internet service providers; and expand protection to technological measures. However, copyright expansion should not be unlimited and should cease when appropriate access to various works and future creations is at risk. Expansion of copyright protection is only justified when the access and use of works by the public threaten the incentive of authors to create and reap economic rewards. Overexpansion of copyright protection would again disrupt the balance if access to works is narrowly restricted. Overprotection of copyrights will not only obstruct access to original works, but will also inhibit future creations based on the original works. Based on comparative research on international and regional conventions as well as laws, regulations, policies and cases among different jurisdictions, this thesis intends to suggest proposals to recover the balance of interests among copyright holders, technological intermediaries and public users in terms of accessing, distributing and exploiting copyrighted works. Four specific issues are discussed in the thesis: the anti-circumvention rules for protection of technological measures; indirect infringing liability for internet service providers and safe harbor regulations; copyright limitations and exceptions especially under the digital network environment; and digital commons projects which promote distribution and adaptation of copyrighted works placed under voluntary licensing schemes. The analysis of these issues and corresponding proposals for reform are not only to reverse the worldwide copyright expansion trend so as to make copyright laws appropriately respond to digital network challenges and the emerging remix culture in general, but also to induce China to rethink and amend her copyright system so as to restore a robust public domain where existing information and data can be used to produce future intellectual assets. / published_or_final_version / Law / Doctoral / Doctor of Philosophy

High-throughput gene expression data have been generated on a large scale by biologists. The thesis describe a set of tools for the analysis of such data. It is specially gearded towards microarray data.

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