Database Research Group Events

Winter 2003

Note: Events of interest to the Database Research Group are posted to the uw.cs.database newsgroup and are mailed to the dbgroup mailing lists: db-faculty (for DB group faculty), db-grads (for DB group graduate students), and db-friends (for DB group alumni, visitors, and friends). If you wish to subscribe to one of these lists, send mail to majordomo@db with "subscribe <list>" in the message body, where <list> is the list you wish to subscribe to.  For example, use "subscribe db-friends" to subscribe to the db-friends list. To unsubscribe, send "unsubscribe <list>" to the same address.
DB group meetings
The DB group meets most Friday afternoons at 2pm, usually in DC1331. See the list of current events for times and locations of upcoming meetings. Each meeting lasts for an hour and features an informal presentation by one of the members of the group. Everyone is welcome to attend. These talks are intended to raise questions and to stimulate discussion rather than being polished presentations of research results. Speakers are determined using a rotating speaker list, which can be found on the DB group meeting page
DB seminar series
The DB seminar series features visiting speakers. These seminars are more-or-less monthly, and are usually scheduled on Monday mornings at 11am. See the list of current events for times and locations of upcoming seminars. The full schedule can be found on the DB seminar series page.

Recent and Upcoming Events


DB meeting: : Friday, January 10th, 2:00 pm, DC1331
Speaker: : Hui Zhang
Topic: : Querying relational storage wrapped with XML views
Abstract: The rapid adoption of XML as a data exchange format on the Web with the reality that a large portion of data is still stored in relational tables requires many Web applications to query relational data through XML views. In this talk, I will present how to query relational storage wrapped with XML views by using our Text/Relational query processing and optimization framework. However, our focus is not on traditinoal view resolution issues. Instead, we focus on how to develop query rewritings to translate an XQuery posed on XML views to the SQL query that is formulated for relational data directly.

DB meeting: : Friday, January 17th, 2:00 pm, DC1331
Speaker: : Ningyan Zhong
Topic: : Melody Constraint
Abstract: Content-based retrieval has been studied for many years in many different forms of media. Now on  internet large volumn of music are stored in MP3 or MIDI format, which contribute to a huge music database for us. A more natural way of searching a song is by humming or singing, especially when people can not remember the title, singer's name or even a little lyric, but a piece of melody of it. This seminar is  about how to represent melody so that such query is possible and efficient. Currently, there exist two kinds of representation---contour-based and interval-based, and they have been successfully applied in many music systems, such as MELDEX, SEMEX. However, we propose  a constraint-based method,  taking melody as a type of constraint, and we give a linear time algorithm Reduce to find its canonical form. This representation is as precise as interval-based method, but overcomes some problem of its redundant searching. Another feature of constraint representation is, besides relative interval information, "tonal context" (an important factor of music) is taken into account.   This feature makes it not only a good candidate for building up an efficient music database system, but also a potential tool for analyzing, understanding, and composing music by computer.

DB Seminar : Tuesday, January 21st, 1:00 pm, MC5136
Speaker: : Björn Þór Jónsson, Reykjavik University
Title : Practical Considerations for Semantic Cache Management


DB meeting: : Friday, January 24th, 2:00 pm, DC3314
Speaker: : Heechul Lim
Topic: : Evaluation of Disk-Based Shortest Path Algorithm
Abstract:
Many solutions to find shortest paths in large networks, such as road map of big city, are proposed recently, due to the increasing use of GIS application. One of the promising solutions is the disk-based shortest path algorithm, which doesn't require much memory to find shortest paths in very large graph.  The problem of the algorithm is the processing time.  This presentation will give a possible solution to speed up the processing time while resources using to execute the algorithm remains about the same.

DB meeting: : Friday, February 7th, 2:00 pm, DC1331
Speaker: : Amir Chinaei
Topic: : Access Control in OODB
Abstract:
This talk introduces some security techniques, specifically concentrating on access control. We start with review of access matrix to some recent models such as Role Based Access Control. To the best of our knowledge, all existing models rely on a centralized administration. Our research is taking steps to design a decentralized access control system in which no one has administrative superiority, and at the same time, all users’ documents are secure. This model exploits some concepts of the RBAC model, XML structures, and object-oriented databases. We eagerly anticipate your feedback.

DB meeting: : Friday, February 14th, 2:00 pm, DC1331
Speaker: : Grant Hutchison
Topic: : Analysis and Survey of Java Data Objects


DB meeting: : Friday, February 28th, 2:00 pm, DC1331
Speaker: : Charlie Clarke
Topic: : Using Structured and Unstructured Data for Open-Domain Question Answering


DB meeting: : Friday, March 7th, 2:00 pm, DC1331
Speaker: : Lukasz Golab
Topic: : Processing Joins in Continuous Queries Over Data Streams
Abstract:
We study sliding window multi-join processing in continuous queries over data streams. Several algorithms are reported for performing continuous, incremental joins, under the assumption that all the sliding windows fit in main memory. The algorithms include multi-way incremental nested loop joins (NLJs) and multi-way incremental hash joins. We also propose join ordering heuristics to minimize the processing cost per unit time. We test
a possible implementation of these algorithms and show that, as expected, hash joins are faster than NLJs for performing equi-joins, and that the overall processing cost is influenced by the strategies used to remove expired tuples from the sliding windows.

This talk is based on a paper which may be found at http://db.uwaterloo.ca/~ddbms/publications/stream/multijoins.pdf


DB Seminar : Friday, March 14th, 2:00 pm, DC1304
Speaker: : Michael Franklin, University of California, Berkeley
Title TelegraphCQ: Continuous Dataflow Processing for an Uncertain World

DB meeting: : Friday, March 21st, 2:00 pm, DC1331
Speaker: : Dong Hui (Terry) Zhuo
Topic: On Fine-Grained Access Control for XML
Abstract:
Fine-grained access control for XML is about controlling access to XML documents at the granularity of individual elements or attributes. This talk describes two problems related to the XML access control. The first problem is the secure evaluation of XPath expressions. While most of the existing XML access control mechanisms use a view-construction technique, we developed a mechanism on the basis of query rewriting. A query rewriting based mechanism might be more efficient in protecting large XML documents against query based access. The second problem is how to provide a compact representation of the access matrix. In order to speed up the authorization decision making, most access control mechanisms choose to materialize the access matrix. The fine-grained nature of XML access control, however, makes the space cost of matrix materialization a significant issue. Our experimental study shows that the access matrices, although large, are very redundant. We proposed a code-book based technique that exploits this redundancy, and we compare it to CAM, a recently proposed alternative solution to the same problem.

DB meeting: Friday, March 28th, 2:00 pm, DC1331
Speaker: Robert Warren
Topic: Record linkage for database integration
Abstract:
In this talk we introduce the problem of Record Linkage which deals with identifying records from different databases referring to the same entity.  This problem is especially relevant to database integration as no explicit information may be available to link their contents.

Basic record matching techniques will be outlined based on the work of Newcombe and possible data integration issues identified. Current research trends and methodologies will also be briefly reviewed.


DB meeting: Friday, April 4th, 2:00 pm, DC1331
Speaker:   Anil Goel
Topic: I'll discuss some work done in the area of selectivity estimation of LIKE predicates. In particular, I will describe, in detail, a technique proposed by Krishnan, Vitter, and Iyer and, time permitting, will talk about a simpler approach implemented by us for a reduced instance of the same problem.

DB meeting: : Friday, April 11th, 2:00 pm, DC1331
Speaker: : Khuzaima Daudjee
Topic: Lazy Database Replication With Freshness Guarantees
Abstract:
Lazy replication is a popular technique for improving the performance and availability of database systems. Although there are concurrency control techniques which guarantee
serializability in lazy replication systems, these techniques do not provide freshness guarantees.  Strong serializability avoids such problems, but it is very costly to implement.  We propose a generalized form of strong serializability that is suitable for use with lazy replication.  It has many of the advantages of strong serializability, but can be implemented more efficiently. We show how generalized strong serializability can be implemented in a lazy replication system, and present the results of a simulation study that quantifies the strengths and limitations of the approach.


DB Seminar : Monday, April 14th, 11:00 am, DC1304
Speaker: : Luis Gravano, Columbia University
Title Hidden-Web Databases: Classification and Search

DB meeting: : Friday, April 25th, 2:00 pm, DC1331
Speaker: : Glenn Paulley
Topic: Overview of SQL Anywhere technologies
Abstract:
iAnywhere Solutions , based in Waterloo, develops and markets Sybase SQL Anywhere, a full-featured relational database product targetted at the small-to-medium sized business marketplace. In this talk I'll give an overview of Sybase SQL Anywhere and some of its underlying technologies, including aspects of: Adaptive Server Anywhere, our database server; UltraLite, our "fingerprint-sized" main memory database for handheld devices; and MobiLink and SQL Remote, our replication technologies.


This page is maintained by  Ken Salem.