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.

Diverse Palindromic Factorization Is NP-complete

Abstract: We prove that it is NP-complete to decide whether a given string can be factored into palindromes that are each unique in the factorization.

Playmakers in multiplayer game communities: their importance and motivations for participation

Abstract: In many game-like open-ended multiplayer communities, the success of the game, and well-being of the community, depends on the efforts of certain individuals who arrange resources for gameplay to other players. These include e.g. game masters, server hosts, and fan site creators. We identify the importance of these voluntary "playmakers" by describing their activities in four communities: (1) Habbo Hotel moderators, creative room designers and fan site builders, (2) Live-action role-playing game masters and non-player characters, (3) Geocaching cache creators, and (4) Neverwinter Nights dungeon masters, player guides, developers, and server hosts. Based on an analysis of this empirical data we describe motivations that the playmakers have for participation in game community activities. Such descriptions will help to improve design for games where playmaker involvement is of critical importance to the game's success.

The Clash between Privacy and Automation in Social Media

Abstract: Classic research on human factors has found that automation never fully eliminates the human operator from the loop. Instead, it shifts the operator's responsibilities to the machine and changes the operator's control demands, sometimes with adverse consequences, called the "ironies of automation." In this article, the authors revisit the problem of automation in the era of social media, focusing on privacy concerns. Present-day social media automatically discloses information, such as users' whereabouts, likings, and undertakings. This review of empirical studies exposes three recurring privacy-related issues in automated disclosure: insensitivity to situational demands, inadequate control of nuance and veracity, and inability to control disclosure with service providers and third parties. The authors claim that "all-or-nothing" automation has proven problematic and that social network services should design their user controls with all stages of the disclosure process in mind.

A temporally adaptive content-based relevance ranking algorithm

Abstract: In information retrieval relevance ranking of the results is one of the most important single tasks there are There are many diffierent ranking algorithms based on the content of the documents or on some external properties eg link structure of html documentsWe present a temporally adaptive content-based relevance ranking algorithm that explicitly takes into account the temporal behavior of the underlying statistical properties of the documents in the form of a statistical topic model more we state that our algorithm can be used on top of any ranking algorithm

A rank-based sequence aligner with applications in phylogenetic analysis.

Abstract: Recent tools for aligning short DNA reads have been designed to optimize the trade-off between correctness and speed. This paper introduces a method for assigning a set of short DNA reads to a reference genome, under Local Rank Distance (LRD). The rank-based aligner proposed in this work aims to improve correctness over speed. However, some indexing strategies to speed up the aligner are also investigated. The LRD aligner is improved in terms of speed by storing [Formula: see text]-mer positions in a hash table for each read. Another improvement, that produces an approximate LRD aligner, is to consider only the positions in the reference that are likely to represent a good positional match of the read. The proposed aligner is evaluated and compared to other state of the art alignment tools in several experiments. A set of experiments are conducted to determine the precision and the recall of the proposed aligner, in the presence of contaminated reads. In another set of experiments, the proposed aligner is used to find the order, the family, or the species of a new (or unknown) organism, given only a set of short Next-Generation Sequencing DNA reads. The empirical results show that the aligner proposed in this work is highly accurate from a biological point of view. Compared to the other evaluated tools, the LRD aligner has the important advantage of being very accurate even for a very low base coverage. Thus, the LRD aligner can be considered as a good alternative to standard alignment tools, especially when the accuracy of the aligner is of high importance. Source code and UNIX binaries of the aligner are freely available for future development and use at http://lrd.herokuapp.com/aligners. The software is implemented in C++ and Java, being supported on UNIX and MS Windows.