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Approximation an Online algorithms for Optimization Problems

Objective

The goal of the project is to contribute to design efficient algorithms with proven worst-case performance guarantees, under strict limitations either on the running time or on the accessibility of the data. For NP-hard optimisation problems, constraints on the running time can often be satisfied by approximation algorithms; the second limitation leads to the notion of on-line algorithms. The project will address its objectives focusing on both traditional paradigmatic problems (graph theoretical, scheduling and packing problems) and algorithmic problems arising in new information technologies (resource management, communication and data management, telecommunication and other areas).

OBJECTIVES
Our theoretical objective is the development of a unified and well defined theory, with respect to computation practice, for approximation and on-line algorithms. The practical objective is to exploit this theory in real world applications and obtain practical algorithmic tools. The theoretically proven algorithms will be used as core algorithmic ideas that reflect the combinatorial structure of problems but need to be fine-tuned to the types of instances arising in specific applications to lead to practical algorithmic tools. Thus, there is a need for implementing and experimenting with the algorithms developed. The feedback from empirical experimentation is also at the basis of the critical revision of theoretical models and design techniques of approximation and on-line algorithms.

DESCRIPTION OF WORK
The design and management of computer systems and communication networks give rise to many combinatorial optimisation problems, that are usually NP-hard. We are interested in efficient algorithms that allow obtaining, on every input instance of a specific problem, a provably good solution, e.g. which is within a guaranteed factor (performance ratio) of the optimum. To understand the combinatorial structures that yield efficient approximation algorithms, we will focus on cornerstone problems.
Another source of difficulties that prevents one from obtaining optimal solutions arises when the input instance of a problem is not immediately available, in areas such as resource allocation in operating systems, distributed computing, scheduling, communication network. An on-line algorithm must deal with events as they arrive and take decisions without knowledge of future events.
We will focus on complementing competitive analysis with other tools or more relaxed assumptions that will make the results significant in those cases in which an omni powerful off-line adversary makes competitive analysis too pessimistic and conceals the real performances of an algorithm. New advances in the area should also be evaluated from a practical point of view by experimenting and by providing guidelines for improving heuristics. Thus, we will implement and experimentally evaluate the algorithms developed.

Funding Scheme

THN - Thematic network contracts

Coordinator

CHRISTIAN-ALBRECHTS-UNIVERSITAET ZU KIEL
Address
Olshausenstrasse 40
24098 Kiel
Germany

Participants (14)

ALBERT-LUDWIGS-UNIVERSITAET FREIBURG
Germany
Address
Fahnenbergplatz
79085 Freiburg
ATHENS UNIVERSITY OF ECONOMICS AND BUSINESS / RESEARCH CENTER
Greece
Address
Patision 76
10434 Athens
EIDGENOESSISCHE TECHNISCHE HOCHSCHULE ZUERICH
Switzerland
Address
Raemistrasse 101
8092 Zuerich
KATHOLIEKE UNIVERSITEIT LEUVEN
Belgium
Address
Oude Markt 13
3000 Leuven
MAX PLANCK GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN E.V.
Germany
Address
Hofgartenstrasse 8
80539 Muenchen
NATIONAL TECHNICAL UNIVERSITY OF ATHENS
Greece
Address
9, Heroon Polytechniou Str.
15773 Athens
TECHNION RESEARCH AND DEVELOPMENT FOUNDATION LTD.
Israel
Address
Technion City
32000 Haifa
TEL AVIV UNIVERSITY
Israel
Address
Ramat Aviv
69978 Tel Aviv
UNIVERSITA DEGLI STUDI DI ROMA "LA SAPIENZA"
Italy
Address
Piazzale Aldo Moro 5
00185 Roma
UNIVERSITAET DORTMUND
Germany
Address
August-schmidt-strasse 4
44227 Dortmund
UNIVERSITE D'EVRY-VAL D'ESSONNE
France
Address
Boulevard Francois Mitterand
91025 Evry-val D'essonne
UNIVERSITE DE PARIS XI PARIS-SUD
France
Address
15, Rue Georges Clemenceau
91405 Orsay Cedex
UNIVERSITEIT MAASTRICHT
Netherlands
Address

6200 MD Maastricht
UNIVERSITY OF SZEGED - JUHASZ GYULA TEACHER TRAINING COLLEGE
Hungary
Address
Boldogasszony Str.6
6701 Szeged