Instituttseminar 2007

• Fall 2007

Fall 2007

 

September 6

Professor Brian S Hoyle, University of Leeds, UK
Title: Spatially Critical Sensor and Actuation Networks.

Abstract: Sensor and actuation networks offer a generic platform from which a wide range of applications can be realised in many fields. Many candidate applications have a spatially critical aspect, from environmental monitoring and control to security and surveillance. Communication networks have enabled many distributed applications, and have exploited a wide range of network topologies and technologies.

The presentation reviews the needs of spatially critical applications and proposes new methodologies that aim to exploit wired and wireless sensor and actuation networks to deliver efficient implementations. It contrasts a classical centralized network solution in which spatially critical data will typically be offloaded for analysis; with a smart network solution, which features inter-node cooperation pivoting upon location, and is able to track specified application properties dynamically. A number of examples are discussed.

Speaker: Brian Hoyle is Professor of Vision and Systems and currently a member of the School of Process, Environmental and Materials Engineering. His research interests are based upon systems engineering and specifically in distributed sensing systems and networks and process sensing including process tomography. He is also Director for Enterprise and Knowledge Transfer, Faculty of Engineering University of Leeds, Leeds, UK.

Monday October 1 14:15 in the large auditorium (2144)

Erik Boman, Sandia National Laboratories in Albuquerque, New Mexico, USA.
Title: Combinatorial Scientific Computing: Enabling Petascale Simulations for Science

Abstract: Computer simulation is an increasingly important tool in research and science. Combinatorial scientific computing is the use of combinatorial and discrete techniques to enable large-scale scientific computing. We first give an overview of research activities in the CSCAPES institute (supported by the US DOE), including load-balancing, automatic differentiation, graph coloring, and sparse matrix ordering. Then we present a more detailed account of partitioning and load-balancing algorithms for parallel scientific computing.

October 4

Thomas Ågotnes, Høgskolen i Bergen
Title: Aggregation and Paradoxes.

Abstract: The Department of Informatics has appointed a committee for evaluating a single applicant for a new professorship. The committee members all make up their minds about the following propositions: (i) the applicant should be given an offer if she is qualified, (ii) the applicant is qualified, and (iii) the applicant should be given an offer. There are three committee members, and their view on the questions (i)/(ii)/(iii) are as follows. Member A: yes/yes/yes; member B: yes/no/no; member C: no/yes/no. Since they disagree, they decide to settle the issue by majority voting on each of (i), (ii) and (iii). What do the committee decide? The problem of aggregating information from different sources comes up when we need to combine information from several databases; when you and you spouse need to agree on a new car (preference aggregation); when the beliefs of two experts must be combined; when a group of agents must coordinate to perform a joint action; in e-government mechanisms (preference aggregation again). Yet the aggregation problem, of which the special case of preference aggregation has been studied extensively in social choice theory, is plagued by dilemmas, paradoxes and impossibility results. I will talk about some of these, and about why computer scientists should be concerned.

October 11

Dr. Samuel Subbey, Institute of Marine Research, Bergen, Norway.
Title: Are classical solutions to inverse and ill-posed problems growing long in the tooth?

Abstract: Starting with data and a general principle or model, inverse theory addresses the problem of estimating the solution set of model parameters. Usually, for a given data set, the solution set is non-unique, and the problem is referred to as being ill-posed.

Classical solutions to inverse and ill-posed problems regularization, i.e., solving a stable variant of the originally unstable problem.

The aim of this talk is to discuss the classical approach to solving inverse and ill-posed problems when the data and model are known with modest accuracy. Simple examples will be presented to highlight key points.

Keywords: Inverse, ill-posed, matrix equation, integral equation, optimization, regularization, parameterization, spline functions

October 18

Markus Roggenbach, Swansea University, UK
Title: CSP - new insights into an old paradigm

Abstract: The process algebra CSP is a well established formalism to model and reason about concurrent systems such as credit card terminals or flight booking systems. For system analysis CSP offers a rich set of process algebraic laws. One fundamental question is: is there a complete set of such algebraic laws? This question has been open for the last 25 years. In our talk, we will report on a completeness result concerning the stable failures model of CSP. We used our tool CSP-Prover to verify our completeness result. This is joint work with Y. Isobe (AIST, Japan).

October 25

Marco Baldi, Universita Politecnica delle Marche, Ancona, Italy
Title: McEliece cryptosystem based on LDPC codes

November 1

Jan Heering, CWI, Amsterdam
Title: Developments in Domain-Specific Languages

Abstract: Domain-specific languages (DSLs) are languages tailored to a specific application domain. They offer substantial gains in expressiveness and ease of use compared with general-purpose languages in their domain of application. Although the use of DSLs is by no means new, it is receiving increased attention in the context of model-driven engineering, development of parallel software for multicore processors, and ultra-large-scale systems. We discuss these trends from the perspective of the roles DSLs have traditionally played.

November 8

Rob Bisseling, University of Utrecht, The Netherlands
Title: To be announced.

November 15

Lars Michael Kristensen Aarhus universitet
Title: To be announced.

December 6

Mikael Rönnqvist, Norwegian School of Economics and Business Administration, Bergen, Norway
Title: Cost sharing in collaborative forest transportation

Abstract: Transportation planning is an important part of the supply chain or wood flow chain in forestry. There are often several forest companies operating in the same region and collaboration between two or more companies is rare. However, there is an increasing interest in collaborative planning as the potential savings are large, often in the range 5-15%. There are several issues to agree on before such collaborative planning can be used in practice. One aspect is to use tailor-made optimization based decision support systems. A second aspect is how savings should be distributed among the participants. We study a number of possibilities based on economic models including Shapley value, the nucleolus, separable and non-separable costs, shadow prices and volume weights. We also propose a new allocation method, with the aim that the participants relative profits are as equal as possible. A large case study comprising eight forest companies in Sweden analyzed.

December 13

Douglas Rogers
Title: On Golden Plan?

Abstract: It has recently been suggested that the influence of golden section was at work in the ground plan of the Sidi Oqba Mosque, in Kairouan, Tunisia. The geometry inherent in such a plan is examined and found to have much in common with some well-known 'vanishing area' puzzles. However, such puzzles may themselves have arisen out of a geometrical misconception in an architecture handbook from 1545, while their association with the Fibonacci numbers may have originally been more a matter of happy accident than design.

Spring 2007

January 25

Kjell Jørgen Hole
Title: Nettbanksikkerhet i perioden 2003-2006.

February 1

Douglas Rogers
Title: After Euler - permutations with and without cycles of prescribed length

February 8

No seminar

February 15

Boris Lenhard, CBU
Title: Gene regulation and animal development: a bioinformatics approach

February 22

Dag Finne, BTO
Tema: Kommersialisering av forskningsresultat

March 1

No seminar
The lecture room will be redecorated.

March 8

Petter Ole Jakobsen, CTO (Teknologi direktør vizrt)
Steinar Søreide, Utviklingssjef Bergen
Vizrt, softwareutvikling, produkter og metoder.

March 15

Min Chen
CANCELLED

March 22

Fredrik Manne
Title: Self-stabilizing Algorithms

March 30, Kl. 10-11 (Note time)

Irina Naydenova
Title: Theory of Unequal Error Protection Codes
(førelesing med fritt valgt emne for PhD)

April 5

NO SEMINAR (Easter vacation)

April 12

Trond Steihaug
Title: CPR and Beyond

April 19

Hamid R. Sadjadpour, University of California, Santa Cruz
Title: Many-to-many communications for ad hoc networks.

On Friday, April 20, 1015-1100, Professor Sadjadpour will give a follow up talk in the Selmer Center (meeting room 5th floor).
Title: Beyond Network Coding: Toward Scalable Ad Hoc Networks

April 26

NB! In aud. 2142.
Dominique Aze, Univ. Paul Sabatier, Toulouse
Title: The Ekeland Variational Principle Revisited

May 3

Matthew Parker
Title: A New Take on Complementary Sequence Construction

May 10

Aslak Tveito, Simulasenteret
Title: Om Simulasenteret med eksempler fra forskningen

May 17

Ikkje seminar

May 24

Ikkje seminar
(Fagutvalet arrangerer bedriftsbesøk frå Google kl. 1400. Påmelding sjå her )

May 31

Jan Arne Telle, Inst. for informatikk, UiB
Title: Physical Mapping of DNA with some undetected overlaps: an efficient Parameterized Graph Algorithm.

Abstract: In 1994 Ron Shamir proposed the following simplified formulation of the physical mapping problem encountered in molecular biology. The DNA molecule is viewed as an interval on the real line from which we extract clones. The goal is to determine the placement of the clones as subintervals. By tests using probes we have already determined which pairs of clones overlap, although a few overlaps may have gone undetected. The problem is to insert the fewest number k of extra overlaps that will allow an ordering of the clones as subintervals of the real line. The data is modeled as a graph with one vertex per clone and an edge for each overlap, and the decision problem becomes
Input: (G,k) where G a graph and k an integer
Question: Can you add at most k edges to G to get an interval graph?
This problem is NP-complete. Shamir et al posed the question if it was FPT, i.e. if there existed a polynomial-time preprocessing algorithm that would transform any input (G,k) into an input (H,k') having the same yes/no answer and where the size of H was a function of k only. As usual, a solution to this decision problem can be used to solve the original problem. In this talk we present such an algorithm and in particular the bounded-search-tree technique that it uses. This technique is well-known in the field of Parameterized Algorithms that is gaining attention lately as offering practical ways to cope with NP-complete problems.

June 7

Jorge Cardoso, Universidade da Madeira, Portugal
Title: The Semantic Web

Short bio: Dr. Cardoso received his Ph.D. in Computer Science from the University of Georgia, USA. He was the co-organizer and co-chair of the First, Second, and Third International Workshop on Semantic and Dynamic Web Processes and is the editor of 3 books on semantic Web and Web services. He is on the Editorial Board of the Enterprise Information Systems Journal, the International Journal on Semantic Web and Information systems, and the International Journal of Information Technology.