Seminar on Wide-area Data Integration by Prof. Louiqa Raschid

[Subbarao Kambhampati <rao@parichaalak.eas.asu.edu>]

Prof. Louiqa Raschid (University of Maryland) will be giving a
(actually two short) presentation(s) at tomorrow's AI/DB seminar.

Her talks will be on wide-area/web-based data integration (see
abstracts below). 

There may be high-quality cookies to slake your mid-afternoon sugar needs.


(Part of the weekly AI/DB seminar: http://rakaposhi.eas.asu.edu/aidb )

Date: 22 March, 2002 (Friday) Time: 3-4pm
Venue: ERC 593 
   [ERC is the tall building to the right of Noble--as you stand
    outside GWC. 593 is to your left as you come out of elevators.]

    

Speaker: Prof. Louiqa Raschid; UMIACS/Dept of CS/Dept of Mgmt, 
         University of Maryland, College Park
         http://www.umiacs.umd.edu/~louiqa 

Abstracts:

     EFFICIENT EVALUATION OF QUERIES IN A MEDIATOR FOR WEBSOURCES

We   consider an architecture  of  mediators and wrappers for Internet
accessible  WebSources of limited query  capability.   Each call to  a
source is a WebSource  Implementation (WSI) and  it is associated with
both a capability and (a possibly dynamic)  cost.  The multiplicity of
WSIs with varying costs and capabilities increases the complexity of a
traditional optimizer  that must assign WSIs  for each remote relation
in the   query  while generating an  (optimal)   plan.  We   present a
two-phase Web Query Optimizer (WQO).  In a pre-optimization phase, the
WQO selects one  or more WSIs for a  pre-plan; a pre-plan represents a
space of query evaluation plans (plans) based on  this choice of WSIs.
The  WQO uses cost-based heuristics   to  evaluate the  choice of  WSI
assignment  in the  pre-plan and to  choose a  good pre-plan.  The WQO
uses the pre-plan to drive the extended relational optimizer to obtain
the best   plan  for a pre-plan.  A   prototype  of the  WQO has  been
developed.  We compare the effectiveness of the WQO, i.e., its ability
to efficiently search  a large space of  plans  and obtain a  low cost
plan, in comparison to a  traditional optimizer.  We also validate the
cost-based heuristics by  experimental  evaluation of queries   in the
noisy Internet environment.



	  PERFORMANCE MONITORING FOR WIDE AREA APPLICATIONS

Recent technology advances  have  enabled wide area  applications with
Internet accessible sources.  A  challenge to such applications is the
unpredictable behavior of  sources in the dynamic  WAN.   There can be
wide variability in the latency (end-to-end  delay) of accessing these
sources,  and this could depend on  network and server workloads.  The
success of these applications will depend  on their ability to monitor
and predict end-to-end  client-side performance.  Our objective is  to
explore open technology for  passive performance monitoring to develop
performance  profiles  for  clusters of clients    and  servers.  Such
technology must be scalable to large numbers of clients and servers.