## CWI Scientific Meeting

Dear colleagues,

This is the second announcement of the CWI
Scientific Meeting this Friday, February 3. We'll have four
presentations by postdocs, one from each cluster. 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 3

Time: 13.00 - 14.00

Room: Euler (Z009)

Speakers:

1. Vadim Zaytsev (SEN): The Life Cycle of Grammarware

2. Tobias Marschall (MAC): Efficient Exact Motif Discovery

3. Bart Scheers (INS): Where CWI touches the Sky

4. Erwin Dassen (PNA): Lattices in cryptography

ABSTRACTS

1. Vadim Zaytsev (SEN): The Life Cycle of Grammarware

Abstract:
The grammar theory is well-known for being a useful and mature
instrument to investigate the structure of software, with grammars being
finite definitions of software languages which often turn out to be
infinite themselves. It is commonly assumed that this theory has solved
all its problems years ago. However, many issues arise in practice, and
the domain and theory of grammarware engineering are still
underdeveloped. In this talk, I will elaborate on such unresolved issues
and provide examples from recent research.

2. Tobias Marschall (MAC): Efficient Exact Motif Discovery

Abstract:
The motif discovery problem consists of uncovering exceptional patterns
(called motifs) in sets of sequences. It arises in molecular biology

when
searching for yet unknown functional sites in DNA sequences. We present
a motif discovery algorithm that (1) is exact, that means it returns a
motif with optimal score, (2) can use the statistical significance with
respect to complex background models as a scoring function, (3) takes
into account the effects of self-overlaps of motif instances, and (4) is
efficient enough to be useful in large-scale applications. An Open
Source implementation of the algorithm is publicly available
(http://mosdi.googlecode.com).

3. Bart Scheers (INS): Where CWI touches the Sky

Abstract:
Next generation astronomical observatories are designed for high-speed
all-sky surveys, searching for rapid transient and variable sources,

cataloguing
repeated measurements of the millions of sources. Consequential, these
facilities will produce tens of terabytes per day. High-cadence data
rates of tens of gigabits per second are not exceptional. LOFAR, the Low
Frequency Array, is a radio telescope that is designed according to
these principles. It is an excellent example where the fields of
astronomy, engineering, computer science and informatics overlap and
cross each other. In fact, the next-generation telescopes cannot succeed
without one of the disciplines.

CWI, in particular INS, enters the
interdisciplinary "field" with its expertise of a fast column-store that
can data mine the hundreds of TBs. In this talk, I will give an
overview of the telescope, its scientific goals, and what makes the sky a
bit more CWI-ish.

4. Erwin Dassen (PNA): Lattices in cryptography

Abstract:
The aim of the talk is to introduce, on a very high level, lattices
(groups, not ordered sets) and how they are currently used in
cryptography. We explain the "hard" lattice problems used as base for
the security of those cryptosystems and what is meant with a fully
homomorphic encryption scheme.