Seminar by prof. Ivana Podnar Zarko (University of Zagreb, Croatia)


Welcome to the talk by prof.
Ivana Podnar Zarko  (University of Zagreb, Croatia)

TITLE: Top-k/w publish/subscribe: A
publish/subscribe model for continuous top-k processing over distributed data

WHEN: Sep 09 Fri, 10:00

WHERE: SICS, Knuth seminar room

ABSTRACT: The problem of information
overload is apparent in our daily lives: When checking RSS feeds from major
media sources, browsing through blog posts and status updates on social sites,
or following tweets to find breaking news, it is difficult to distinguish
information relevant to personal interest in real-time. Moreover, emerging data
stream applications spanning
over largely-distributed data sources, such as the Sensor Web, generate vast data volumes, and require continuous processing
and data filtering, preferably close to data sources.


This talk addresses continuous
processing of top-k queries over distributed data streams which filters out
irrelevant data stream objects, and delivers only top-k objects relevant to
current interests in real-time. Thus it offers the means to alleviate the
information overload problem. Our solution---top-k publish/subscribe over sliding windows (top-k/w publish/subscribe)---identifies k best-ranked objects with respect to an
arbitrary scoring function over a sliding window w, and is based on the
publish/subscribe communication paradigm augmented by algorithms coming from
the field of data stream processing. We investigate the properties of
the top-k/w publish/subscribe model through an extensive experimental
evaluation, and compare it to the prevailing Boolean publish/subscribe model. Furthermore, we propose novel
centralized algorithms for efficient top-k/w processing, and provide a
comparative evaluation which shows the proposed algorithms outperform the
competing approaches by orders of magnitude. Finally, we present possible model
implementations in distributed environments, and provide a comparative study
investigating traffic requirements of potential routing strategies.


Podnar Zarko is assistant professor at the Faculty of Electrical Engineering
and Computing, University of Zagreb, Croatia (UNIZG-FER). She has been
affiliated with the Department of Telecommunications at UNIZG-FER since 1997,
initially as research assistant, and currently as assistant professor. She was
a guest researcher (2000) and research associate (2001) at the Distributed
Systems Group, Technical University of Vienna, and a postdoctoral researcher
(2005-2006) at the Distributed Information Systems Laboratory of the Swiss
Federal Institute of Technology in Lausanne (EPFL). Her main research interests
are on large-scale distributed systems and real-time data processing, in
particular, publish/subscribe systems, data stream processing, and information
retrieval in P2P networks. She has co-authored 31 scientific journal and
conference papers in these domains, and has served as a program committee
member for a number of international conferences and workshops. She has
experience of participating in projects founded by the EU Framework Programme,
and currently participates in COST Action IC0906 WiNeMO - Wireless Networking
for Moving Objects. She is a member of IEEE and the Chapter Chair of IEEE
Communications Society – Croatia Chapter.







Friday, September 9, 2011, 12:00