Uncertain Data Integration with Probabilities

Real world applications that deal with information extraction, such as business intelligence software or sensor data management, must often process data provided with varying degrees of uncertainty. Uncertainty can result from multiple or inconsistent sources, as well as approximate schema mappings. Modeling, managing and integrating uncertain data from multiple sources has been an active area of research in recent years [6][7][1][2]. In particular, data integration systems free the user from the tedious tasks of finding relevant data sources, interacting with each source in isolation using its corresponding interface and combining data from multiple sources by providing a uniform query interface to gain access to the integrated information [5]. Previous work has integrated uncertain data using representation models such as the possible worlds and probabilistic relations [12][1][2]. We extend this work by determining the probabilities of possible worlds of an extended probabilistic relation. We also present an algorithm to determine when a given extended probabilistic relation can be obtained by the integration of two probabilistic relations and give the decomposed pairs of probabilistic relations. iii ACKNOWLEDGEMENTS I sincerely thank my advisor, Dr. Fereidoon Sadri, for his abundant guidance and support throughout the course of this research without which this thesis would not have been possible. I am very thankful to him for giving me the opportunity to work with him and believing in me. I thoroughly enjoyed working under him. I would also like to thank Dr. Jing Deng and Dr. Nancy Green for their valuable guidance and feedback. I am indebted to my husband for his constant encouragement, support and love. I am very grateful to my mother and my family members for their unconditional support and care. I want to thank Nina Revankar and her family for their ample love and concern during my study. Nina's spontaneous gestures of help on those busy days really made a big difference, and I am deeply indebted to her for it. I would like to express my gratitude to my friends at School for cheering me up and encouraging me all through. I am highly grateful to all my dear friends in Greensboro for keeping my life outside School fun at all times, and for their endless concern and support throughout.