Helsinki Institute for Information Technology

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.

Analysis of the HIP base exchange protocol

Abstract: The Host Identity Protocol (HIP) is an Internet security and multi-addressing mechanism specified by the IETF. HIP introduces a new layer between the transport and network layers of the TCP/IP stack that maps host identifiers to network locations, thus separating the two conflicting roles that IP addresses have in the current Internet. This paper analyzes the security and functionality of the HIP base exchange, which is a classic key exchange protocol with some novel features for authentication and DoS protection. The base exchange is the most stable part of the HIP specification with multiple existing implementations. We point out several security issues in the current protocol and propose changes that are compatible with the goals of HIP.

Everyday appropriations of information technology: A study of creative uses of digital cameras

Abstract: Repurposive appropriation is a creative everyday act in which a user invents a novel use for information technology (IT) and adopts it. This study is the first to address its prevalence and predictability in the consumer IT context. In all, 2,379 respondents filled in an online questionnaire on creative uses of digital cameras, such as using them as scanners, periscopes, and storage media. The data reveal that such creative uses are adopted by about half of the users, on average, across different demographic backgrounds. Discovery of a creative use on one's own is slightly more common than is learning it from others. Most users discover the creative uses either completely on their own or wholly through learning from others. Our regression model explains 34% of the variance in adoption of invented uses, with technology cognizance orientation, gender, exploration orientation, use frequency, and use tenure as the strongest predictors. These findings have implications for both design and marketing. © 2011 Wiley Periodicals, Inc.

Properties of the Steiner Triple Systems of Order 19

Abstract: Properties of the 11 084 874 829 Steiner triple systems of order 19 are examined. In particular, there is exactly one 5-sparse, but no 6-sparse, STS(19); there is exactly one uniform STS(19); there are exactly two STS(19) with no almost parallel classes; all STS(19) have chromatic number 3; all have chromatic index 10, except for 4 075 designs with chromatic index 11 and two with chromatic index 12; all are 3-resolvable; and there are exactly two 3-existentially closed STS(19).

Identification of structural features in chemicals associated with cancer drug response: a systematic data-driven analysis

Abstract: Motivation: Analysis of relationships of drug structure to biological response is key to understanding off-target and unexpected drug effects, and for developing hypotheses on how to tailor drug therapies. New methods are required for integrated analyses of a large number of chemical features of drugs against the corresponding genome-wide responses of multiple cell models. Results: In this article, we present the first comprehensive multi-set analysis on how the chemical structure of drugs impacts on genomewide gene expression across several cancer cell lines [Connectivity Map (CMap) database]. The task is formulated as searching for drug response components across multiple cancers to reveal shared effects of drugs and the chemical features that may be responsible. The components can be computed with an extension of a recent approach called Group Factor Analysis. We identify 11 components that link the structural descriptors of drugs with specific gene expression responses observed in the three cell lines and identify structural groups that may be responsible for the responses. Our method quantitatively outperforms the limited earlier methods on CMap and identifies both the previously reported associations and several interesting novel findings, by taking into account multiple cell lines and advanced 3D structural descriptors. The novel observations include: previously unknown similarities in the effects induced by 15-delta prostaglandin J2 and HSP90 inhibitors, which are linked to the 3D descriptors of the drugs; and the induction by simvastatin of leukemia-specific response, resembling the effects of corticosteroids. Availability and implementation: Source Code implementing the method is available at: http://research.ics.aalto.fi/mi/software/GFAsparse Contact: suleiman.khan@aalto.fi or samuel.kaski@aalto.fi Supplementary Information: Supplementary data are available at Bioinformatics online.