[Please remove <h1>]
Winter 2002
DB
meeting: |
Friday, January 11th, 2:00 pm, DC1331 |
Speaker: |
Ivan Bowman |
Topic: |
Reducing Client/Server Latency by Detecting Stylized Usage |
Snacks: |
Hui Zhang |
Abstract: |
Current applications in client-server database systems
may suffer a performance penalty due to the latency associated
with networked communication. By recognizing
stylized patterns in the requests submitted by applications, we
can reduce this latency through prefetching
of results that are likely to be needed in the near future. We can
do even better if we can recognize patterns that can be implemented
using relational primitives such as joins
and unions; these can be processed more
efficiently if expressed as queries to the database engine. This
talk will discuss the types of patterns that commonly
occur in database client applications, and will show
how these patterns can be effectively recognized
and exploited to improve performance. |
DB
meeting: |
Friday, January 18th, 2:00 pm, DC1304 |
Speaker: |
Ningyan Zhong |
Topic: |
Constraint Databases |
Snacks: |
Ivan Bowman |
Abstract: |
Constraint Databases was initiated in 1990, and grew out of
the research on Datalog and Constraint Logic Programming. The key idea
is that the notion of a tuple in a relational database could be replaced
by a conjunction of constraints from an appropriate language, and many
of the features of the relational model could be extended in an appropriate
way. In CDB, the infinite data can be stored in a finite and compact way,
and the query complexity doesn't depend on the size of the data. In this
talk, we will give a brief introduction to CDB(definition,expressive power,
and application). Then some issues in Constraint Logic Programming will
be discussed(constraint solving techniques in LP). The main purpose
of this talk is to illustrate a framework of constraint extension on datalog--a
technique based on program transformation and constraint operations' definition.
Together with examples implemented on several different constraint classes,
we will also introduce two optimization techniques(partial evaluation and
memoing evaluation on constraint). Finally, the talk will be concluded
with some future work. |
DB
meeting: |
Friday, January 25th, 2:00 pm, DC3301
(the DB Lab) |
Speaker: |
come for a coffee break - no speaker today |
DB
meeting: |
Friday, February 8th, 2:00 pm, DC1331 |
Speaker: |
Yasser Ebrahim |
Topic: |
Mental Models and Comprehension of Diagrammatic Representations |
Snacks: |
Ningyan Zhong |
DB
meeting: |
Friday, February 15th, 2:00 pm, DC1331 |
Speaker: |
Glenn Paulley |
Topic: |
The Index Selection Problem |
Snacks: |
Yasser Ebrahim |
Abstract: |
A long-standing research problem in physical database design
is the index selection problem (ISP). Essentially the ISP is: given a database
instance and a workload comprised of both queries and update DML statements,
determine the optimal set of indexes that results in the lowest overall
elapsed time. Usually the problem is constrained in some way: two typical
examples are
-
at most k indexes can be created, or
-
the sum of the sizes of the recommended indexes may not exceed n disk pages.
In this talk I will give a critical overview of some of the ISP research
literature that has been published since 1973, and describe recent attempts
to solve this problem in commercial database systems, namely DB2 and Microsoft
SQL Server. |
DB
meeting: |
Friday, March 1st, 2:00 pm, DC1331 |
Speaker: |
Charlie Clarke |
Topic: |
A Domain-Specific Language for Web Data Gathering |
Snacks: |
Glenn Paulley |
DB
meeting: |
Friday, March 8th, 2:00 pm, |
Speaker: |
Ning Zhang |
Topic: |
Towards Optimization of XML Query - A First Step |
Snacks: |
Charlie Clarke |
DB
meeting: |
Friday, March 15th, 2:00 pm, DC1331 |
Speaker: |
Ani Nica |
Topic: |
Optimization techniques for queries containing subqueries and
aggregations |
Snacks: |
Ning Zhang |
Abstract: |
In this talk I will present an overview of subquery evaluation techniques.
The overview will cover optimizations such as correlation removal, subquery
flattening and using outerjoins for subquery executions. The presentation
will include examples of how these techniques are used for queries from
TPC-H benchmark. |
DB
meeting: |
Friday, March 22nd, 2:00 pm, DC1331 |
Speaker: |
Khuzaima Daudjee |
Topic: |
I will talk about Data Staging for On-Demand Broadcast by Aksoy,
Franklin & Zdonik from VLDB'01. |
Snacks: |
Ani Nica |
DB
meeting: |
Friday, April 5th, 2:00 pm, DC1331 |
Speaker: |
Xuerong Tang |
Topic: |
Three perspectives on XSLT |
Snacks: |
Khuzaima Daudjee |
Abstract: |
XSLT (eXtensible Stylesheet Language Transformation) is a language
for transforming one XML document into another. It defines a transformer
serving as part of W3C XSL specification which also contains a second piece:
a formatting vocabulary. Since XSLT became a recommendation in W3C at 1999,
it has generated a lot of interests among programmers, database theoreticians
and curious normal users, which brings three different perspectives on
XSLT. I will informally talk about these perspectives one by one. |
DB
meeting: |
Friday, April 12th, 2:00 pm, DC1331 |
Speaker: |
Grant Weddell |
Topic: |
Fine Grained Information Integration with Description Logic |
Snacks: |
Xuerong Tang |
DB
meeting: |
Friday, April 19th, 2:00 pm, DC1331 |
Speaker: |
Kong Ching Ma |
Topic: |
Approximate Query Answering for Aggregate Queries |
Snacks: |
Grant Weddell |
Abstract: |
Over the last decade, we have seen the trend of using large-scale
database to support decisions in applications known as Online Analytical
Processing (OLAP) applications. The database used in these systems
are so large that the traditional query answering techniques will take
a very long time to finish. To take advantage of the fact that users
of these applications do not require a very accurate answer, there are
different approaches to minimize the response time at the expense of accuracy.
This is a survey of the current approaches to approximate such queries.
(PowerPoint slides) |
DB
meeting: |
Friday, April 26th, 2:00 pm, DC1331 |
Speaker: |
Sunny Lam |
Topic: |
WebQA: A Web Querying System That Uses A QA Approach |
Snacks: |
Kong Ching Ma |
Abstract: |
As the size of the World Wide Web (WWW or Web) has grown, access
to the data on the Web has become a significant problem. Data on the Web
are managed by many individuals, organizations, and companies, they are
stored in many different locations, and adhere to very different formats.
These factors contribute to the difficulty of retrieving Web data. The
common paradigm of searching and retrieving information on the Web is based
on keyword-based search using one or more search engines, and then browsing
through the large number of returned URLs. This thesis investigates a declarative
query-based approach to Web data retrieval that uses question-answering
technology in extracting information from Web sites that are retrieved
by search engines. The approach consists of first using meta-search techniques
in an open environment to gather candidate responses from search engines
and other on-line databases, and then using information extraction techniques
to find the answer to the specific question from these candidates. A prototype
system, called WebQA, has been developed to test this approach. Testing
includes evaluation of its performance as a question-answering system using
a well-known evaluation system called TREC-9. Its accuracy using
TREC-9 data for simple questions is high and its retrieval performance
is good. The system employs an open system architecture allowing
for on-going improvements in various aspects. |
This page is maintained by
Frank
Tompa and
Ken Salem.