Segmented Nestedness in Binary Data

Lecturer : 
Esa Junttila
Event type: 
HIIT seminar
Event time: 
2011-03-25 10:15 to 11:00
Place: 
Kumpula Exactum C222
Description: 

Talk announcement:
HIIT Seminar Kumpula, Friday March 25 10:15, Exactum C222

SPEAKER:
Esa Junttila
University of Helsinki

TITLE:
Segmented Nestedness in Binary Data

ABSTRACT:
Given a data matrix, we can reveal its hidden structure
by permuting the rows and columns. A binary dataset is
nested if every row is a subset or superset of every other row.
Our goal is to develop automatic methods for finding whether
a dataset can be described as a combination of k nested patterns,
even if the data contains noise and errors.
Recognizing k-nestedness takes polynomial time in noise-free case,
but finding a closest k-nested matrix is NP-hard.
We propose heuristic algorithms for k-nestedness
and an MDL-based model for selecting k. Experimental
results show that k-nestedness exists in real-world
datasets, such as in occurrences of mammals in Europe.


Welcome!
--Matti Järvisalo

Digital world in digital era

Lecturer : 
Valentin Polishchuk
Event type: 
HIIT seminar
Event time: 
2011-03-18 10:15 to 11:00
Place: 
Kumpula Exactum C222
Description: 
Talk announcement:
HIIT Seminar Kumpula, Friday March 18 10:15, Exactum C222

SPEAKER:
Valentin Polishchuk
University of Helsinki & HIIT

TITLE:
Digital world in digital era

ABSTRACT:
I will talk about discretization in CS, projecting it on our
current research themes -- how the content of geometer's toolbox
changed from ruler and compass to brooms and bulbs.
Joint thoughts with David Kirkpatrick, Joseph Mitchell, Mikko Sysikaski


Welcome!
--Matti Järvisalo

From Black and White to Full Colour: Extending Redescription Mining Outside the Boolean World

Lecturer : 
Esther Galbrun
Event type: 
HIIT seminar
Event time: 
2011-03-11 10:15 to 11:00
Place: 
Kumpula Exactum C222
Description: 
Talk announcement:
HIIT Seminar Kumpula, Friday March 11 10:15, Exactum C222

SPEAKER:
Esther Galbrun
University of Helsinki

TITLE:
From Black and White to Full Colour: 
Extending Redescription Mining Outside the Boolean World

ABSTRACT:
Redescription mining is a powerful data analysis tool that is used to
find multiple descriptions of the same entities.  However, current
redescription mining methods cannot handle other than Boolean data,
this makes discretization a prerequisite, entailing a possibly harmful
loss of information.  We extend redescription mining to real-valued
data using a surprisingly simple and efficient approach and give an
example of application, for an important task in biology known as
niche-finding.

Redescription mining is a powerful data analysis tool that is used to find 
multiple descriptions of the same entities.  The current redescription 
mining methods cannot handle other than Boolean data, making 
discretization a prerequisite when using non-Boolean data.

We extend redescription mining to real-valued data using a surprisingly 
simple and efficient approach. We demonstrate our algorithm with a 
real-world task of niche-finding, an important problem in biology.

Joint work with Pauli Miettinen


Welcome!
--Matti Järvisalo

Autonomy handover and rich interaction on mobile devices

Lecturer : 
Simon Rogers
Event type: 
HIIT seminar
Event time: 
2011-03-14 13:15 to 14:00
Place: 
Computer Science Building, Hall T2
Description: 

Next week's speaker for joint ICS Forum/HIIT Otaniemi Seminar is Dr. Simon Rogers from the "Inference, Dynamics, and Interaction" group of the University of Glasgow.

 
Joint ICS Forum/HIIT Otaniemi Seminar, Monday March 14, 13:15
Location: Computer Science Building, Hall T2
 
Simon Rogers
Inference, Dynamics, and Interaction Group
University of Glasgow
 
Title:
Autonomy handover and rich interaction on mobile devices
 
Abstract:
In this talk I will present some of the work being done in the new Inference, Dynamics, and Interaction group, at the University of Glasgow. In particular, we are interested in using probabilistic inference to improve interaction technology on handheld devices (particularly with touch screens). I will show how we are using sequential Monte-Carlo techniques to infer distributions over user inputs which can be (1) augmented with applications to provide a smooth handover of control between the human and device and (2) used to extract additional information regarding touch interactions and subsequently improve touch accuracy.
 
Welcome!
 
UPCOMING TALKS OF HIIT OTANIEMI SEMINAR SERIES
----
Mar. 28, Antti Oulasvirta/Teemu Roos
 
 
-- 
Mehmet Gönen
Helsinki Institute for Information Technology HIIT
Aalto University School of Science
Department of Information and Computer Science

 

An excursion into algebraic tools for combinatorial problems

Lecturer : 
Petteri Kaski
Event type: 
HIIT seminar
Event time: 
2011-03-07 13:15 to 14:00
Place: 
Computer Science Building, Hall T2
Description: 

 

Our next speaker for HIIT Otaniemi seminar series is Petteri Kaski from the "New Paradigms in Computing" group of the Helsinki Institute for Information Technology HIIT.
 
All ICS@Aalto researchers are also warmly welcome to attend the seminar!
 
HIIT Otaniemi Seminar, Monday March 07, 13:15
Location: Computer Science Building, Hall T2
 
Petteri Kaski
New Paradigms in Computing Group
Helsinki Institute for Information Technology HIIT
Aalto University School of Science
Department of Information and Computer Science
 
Title:
An excursion into algebraic tools for combinatorial problems
 
Abstract:
Currently the fastest known algorithms for a number of fundamental combinatorial tasks, including graph coloring, Hamilton path/cycle, k-path, k-clique, Steiner tree, counting bipartite perfect matchings, counting forests, set packing, all-terminal reliability, and so forth, rely on fundamentally algebraic tools. That is, the combinatorial problem is first reduced into an appropriate algebraic representation, and then algebraic algorithms are employed to solve the problem.
 
This talk makes a brief survey of the area and highlights some potential future directions.
 
Welcome!
 
UPCOMING TALKS OF HIIT OTANIEMI SEMINAR SERIES
----
Mar. 14, Simon Rogers
Mar. 28, Antti Oulasvirta/Teemu Roos
 
 
-- 
Mehmet Gönen
Helsinki Institute for Information Technology HIIT
Department of Information and Computer Science
Aalto University School of Science

 

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