Sudarshan S. Chawathe

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The goal of the Tsimmis Project is to develop tools that facilitate the rapid integration of heterogeneous information sources that may include both structured and unstructured data This paper gives an overview of the project describ ing components that extract properties from unstructured objects that translate information into a common object model that(More)
Detecting and representing changes to data is important for active databases, data warehousing, view maintenance, and version and configuration management. Most previous work in change management has dealt with flat-file and relational data; we focus on hierarchically structured data. Since in many cases changes must be computed from old and new versions of(More)
We present an external-memory algorithm for computing a minimum-cost edit script between two rooted, ordered, labeled trees. The I/O, RAM, and CPU costs of our algorithm are, respectively, 4mn+7m+5n, 6S, andO(MN+(M+N )S1:5), where M and N are the input tree sizes, S is the block size, m = M=S, and n = N=S. This algorithm can make effective use of surplus(More)
We present the design and implementation of the XSQ system for querying streaming XML data using XPath 1.0. Using a clean design based on a hierarchical arrangement of pushdown transducers augmented with buffers, XSQ supports features such as multiple predicates, closures, and aggregation. XSQ not only provides high throughput, but is also memory efficient:(More)
Detecting changes by comparing data snapshots is an important requirement for difference queries, active databases, and version and configuration management. In this paper we focus on detecting meaningful changes in hierarchically structured data, such as nested-object data. This problem is much more challenging than the corresponding one for relational or(More)
Radio-Frequency Identification (RFID) technology enables sensors to efficiently and inexpensively track merchandise and other objects. The vast amount of data resulting from the proliferation of RFID readers and tags poses some interesting challenges for data management. We present a brief introduction to RFID technology and highlight a few of the data(More)
We have implemented and released the XSQ system for evaluating XPath queries on streaming XML data. XSQ supports XPath features such as multiple predicates, closures, and aggregation, which pose interesting challenges for streaming evaluation. Our implementation is based on using a hierarchical arrangement of augmented finite state automata. A design goal(More)
Semistructured data may be irregular and incomplete and does not necessarily conform to a fixed schema. As with structured data, it is often desirable to maintain a history of changes to data, and to query over both the data and the changes. Representing and querying changes in semistructured data is more difficult than in structured data due to the(More)
Indoor localization refers to the task of determining the location of a traveler in spaces (such as large building complexes or airport terminals) using coordinates appropriate to those spaces (such as floor and room number or airport terminal and gate). Indoor localization using Bluetooth beacons is attractive because of the low cost and high spatial(More)