Dear colleagues,

This is the second announcement of the CWI Scientific Meeting on Friday,
February 8.  We'll have four presentations by postdocs. Titles and
abstracts are given below.  As usual, sandwiches will be provided before
the talks.

We hope to see you at the meeting!

The organizers,
Willem Hundsdorfer and Ronald de Wolf


PROGRAM
Date: Friday, February 8
Time: 13.00 - 14.00
Room: Turing (Z011)

Speakers:
1.  Jiyin He (IA): Interactive information retrieval for complex search tasks
2.  Mark Hills (Swat): A Framework for PHP Program Analysis
3.  Sunil Simon (N&O, SwAT): Social network games
4.  Andras Szabo  (LS): Cell-based modeling of cancerous tissues


ABSTRACTS

1. Jiyin He (IA): Interactive information retrieval for complex search tasks.
Abstract: Search systems have become an integrated part of our work and
home environments, even for complex tasks such as decision making and
learning. To accomplish such tasks with classic search systems, users
are forced to engage in a cycle of repeatedly querying a system to
collect pieces of information, and organizing collected information to
facilitate interpretation. Better support for complex tasks would make
explicit the subsequent stages users go through and reduce the effort
involved. In this talk I will briefly overview research in (interactive)
information retrieval that addresses some of the above problems,
describe some of our own work, and conclude with our envisaged research
goals.

2.  Mark Hills (Swat): A Framework for PHP Program Analysis.
Abstract: PHP, invented by Rasmus Lerdorf in 1994, is an imperative,
object-oriented language focused on server-side application development.
It is one of the most popular programming languages, ranking 6th on the
current TIOBE programming community index, used by almost 79% of all
websites where the server-side language can be determined, and ranking
as the 6th most popular language on GitHub. It is also highly dynamic,
with a number of language features that are challenging for program
analysis tools. However, it is exactly these tools that are needed to
provide the support that developers have come to expect, such as tools
for automated refactoring or for program comprehension. In this talk I
will provide an overview of our current work on building a framework, in
Rascal, for the analysis of PHP programs. I will also discuss our recent
work on empirically examining a large corpus of PHP systems, where we
were able to determine which features of the language are used in
practice and where we identified patterns of dynamic feature usage that
can be exploited in building static analysis tools.

3.  Sunil Simon (N&O, SwAT):  Social network games.
Abstract: Modern game theory, whose foundations lie in the intersection
of mathematics and economics has become an important tool in computer
science. In this work, we use game theory to better understand the
spread of products in a social network. We consider the threshold model
of social networks in which the nodes influenced by their neighbours can
adopt one out of several alternatives, and associate with each social
network a strategic game between the agents.  These games need not
always have a Nash equilibrium and there is no efficient procedure to
determine if a network has a Nash equilibrium. However, there are
natural subclasses of networks for which an equilibrium profile can be
efficiently computed. We also explain how these results can be used to
analyse consequences of the addition of new products to a social network.
   This is joint work with Krzysztof Apt.

4.  Andras Szabo  (LS): Cell-based modeling of cancerous tissues.
Abstract: Cancer is a disease of multicellular regulation: cancer cells
replicate uncontrollably within the tissue, despite the inhibitory
signals from the organism. Traditionally, cancer research focuses on
understanding the disease on the level of individual cells, mapping
changes in the genome. The increased mutation rates, however, introduce
heterogeneity within tumours, and initiate an evolutionary race driven
by competition for limited space and nutrients. In this micro-ecosystem,
survival depends on both the cell's properties (phenotype) and the
cell's environment. We use a mechanistic modeling approach to better
understand the behaviour of this system. In the talk I will introduce
our cell-based tissue model, and show an example of how biophysical cell
properties might influence the population dynamics.