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Institution

Helsinki Institute for Information Technology

FacilityEspoo, Finland
About: Helsinki Institute for Information Technology is a facility organization based out in Espoo, Finland. It is known for research contribution in the topics: Population & Bayesian network. The organization has 630 authors who have published 1962 publications receiving 63426 citations.


Papers
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Journal ArticleDOI
TL;DR: It is shown that the ratio of matched individuals to blocking pairs grows linearly with the number of propose–accept rounds executed by the Gale–Shapley algorithm for the stable marriage problem, allowing a distributed (2+ε)-approximation algorithm for maximum-weight matching in bicoloured graphs and a centralised randomised constant-time approximation scheme for estimating the size of a stable matching.
Abstract: We show that the ratio of matched individuals to blocking pairs grows linearly with the number of propose–accept rounds executed by the Gale–Shapley algorithm for the stable marriage problem. Consequently, the participants can arrive at an almost stable matching even without full information about the problem instance; for each participant, knowing only its local neighbourhood is enough. In distributed-systems parlance, this means that if each person has only a constant number of acceptable partners, an almost stable matching emerges after a constant number of synchronous communication rounds. We apply our results to give a distributed (2+e)-approximation algorithm for maximum-weight matching in bicoloured graphs and a centralised randomised constant-time approximation scheme for estimating the size of a stable matching.

58 citations

Book ChapterDOI
07 Jul 2008
TL;DR: It is shown that the travelling salesman problem in bounded-degreegraphs can be solved in time $O\bigl((2-\epsilon)^n\bigr)$, wheree> 0 depends only on the degree bound but not on the number of cities, n.
Abstract: We show that the travelling salesman problem in bounded-degreegraphs can be solved in time $O\bigl((2-\epsilon)^n\bigr)$, wheree> 0 depends only on the degree bound but noton the number of cities, n. The algorithm is a variant ofthe classical dynamic programming solution due to Bellman, and,independently, Held and Karp. In the case of bounded integerweights on the edges, we also present a polynomial-space algorithmwith running time $O\bigl((2-\epsilon)^n\bigr)$ on bounded-degreegraphs.

58 citations

Proceedings ArticleDOI
23 Feb 2013
TL;DR: An aversion to indebtedness is revealed and several user behaviors that lessen these negative feelings are discussed that can help alleviate the discomfort of indebtedness and better encourage and sustain participation in systems of indirect reciprocity.
Abstract: Many existing and emerging online systems allow people to share content and coordinate the exchange of goods and favors in local geographic settings. We present a qualitative case study of user experiences concerning exchange and reciprocity in local online exchange. Findings from eleven in-depth interviews (containing forty-nine separate exchange experiences) reveal an aversion to indebtedness and several user behaviors that lessen these negative feelings: (1) offering small tokens of appreciation to exchange partners, (2) understanding and accepting the indirect nature of generalized exchange, (3) managing expectations by framing offers and requests carefully, (4) minimizing efforts needed in exchange processes, and (5) bartering and exchanging for a third party. The paper contributes to our understanding of emergent behaviors and norms in local online exchange systems. We discuss design implications from these empirical insights that can help alleviate the discomfort of indebtedness and better encourage and sustain participation in systems of indirect reciprocity.

58 citations

Journal ArticleDOI
TL;DR: BeTelGeuse is an extensible data collection platform for mobile devices, which also automatically infers higher level context from sensor data and its impact on mobile phone performance is evaluated.
Abstract: BeTelGeuse is an extensible data collection platform for mobile devices, which also automatically infers higher level context from sensor data. In this article, the authors introduce BeTelGeuse's architecture and current features, and evaluate its impact on mobile phone performance.

58 citations

Proceedings ArticleDOI
26 Apr 2009
TL;DR: In this paper, the authors present EcoIsland, a system persuading individuals and families to change their lifestyle patterns to reduce CO2 emissions, which visualizes the user's current eco-friendly behavior as an island shared by his/her family members.
Abstract: This paper presents EcoIsland, which is a system persuading individuals and families to change their lifestyle patterns to reduce CO2 emissions. EcoIsland visualizes the user's current eco-friendly behavior as an island shared by his/her family members. Several persuasive techniques developed in behaviorism, social psychology, and economy are used to offer incentives to him/her to encourage eco-friendly behavior. We examine and compare the implementation and effectiveness of different types of persuasive techniques in several user studies.

57 citations


Authors

Showing all 632 results

NameH-indexPapersCitations
Dimitri P. Bertsekas9433285939
Olli Kallioniemi9035342021
Heikki Mannila7229526500
Jukka Corander6641117220
Jaakko Kangasjärvi6214617096
Aapo Hyvärinen6130144146
Samuel Kaski5852214180
Nadarajah Asokan5832711947
Aristides Gionis5829219300
Hannu Toivonen5619219316
Nicola Zamboni5312811397
Jorma Rissanen5215122720
Tero Aittokallio522718689
Juha Veijola5226119588
Juho Hamari5117616631
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20231
20224
202185
202097
2019140
2018127