Showing papers by "Helsinki Institute for Information Technology published in 2002"
TL;DR: The feasibility of this approach is demonstrated by reporting results of field tests in which a probabilistic location estimation method is validated in a real-world indoor environment.
Abstract: We estimate the location of a WLAN user based on radio signal strength measurements performed by the user’s mobile terminal. In our approach the physical properties of the signal propagation are not taken into account directly. Instead the location estimation is regarded as a machine learning problem in which the task is to model how the signal strengths are distributed in different geographical areas based on a sample of measurements collected at several known locations. We present a probabilistic framework for solving the location estimation problem. In the empirical part of the paper we demonstrate the feasibility of this approach by reporting results of field tests in which a probabilistic location estimation method is validated in a real-world indoor environment.
975 citations
TL;DR: In this article, a location estimation method based on a statistical signal power model is proposed. But this method requires nonstandard features either in the mobile terminal or the network, such as the cell-ID method in GSM/GPRS cellular networks, which is usually problematic due to their inadequate location estimation accuracy.
Abstract: Some location estimation methods, such as the GPS satellite navigation system, require nonstandard features either in the mobile terminal or the network. Solutions based on generic technologies not intended for location estimation purposes, such as the cell-ID method in GSM/GPRS cellular networks, are usually problematic due to their inadequate location estimation accuracy. In order to enable accurate location estimation when only inaccurate measurements are available, we present an approach to location estimation that is different from the prevailing geometric one. We call our approach the statistical modeling approach. As an example application of the proposed statistical modeling framework, we present a location estimation method based on a statistical signal power model. We also present encouraging empirical results from simulated experiments supported by real-world field tests.
358 citations
TL;DR: With the restrictions stated in the support material, B-Course is a powerful analysis tool exploiting several theoretically elaborate results developed recently in the fields of Bayesian and causal modeling.
Abstract: B-Course is a free web-based online data analysis tool, which allows the users to analyze their data for multivariate probabilistic dependencies. These dependencies are represented as Bayesian network models. In addition to this, B-Course also offers facilities for inferring certain type of causal dependencies from the data. The software uses a novel "tutorial stylerdquo; user-friendly interface which intertwines the steps in the data analysis with support material that gives an informal introduction to the Bayesian approach adopted. Although the analysis methods, modeling assumptions and restrictions are totally transparent to the user, this transparency is not achieved at the expense of analysis power: with the restrictions stated in the support material, B-Course is a powerful analysis tool exploiting several theoretically elaborate results developed recently in the fields of Bayesian and causal modeling. B-Course can be used with most web-browsers (even Lynx), and the facilities include features such as automatic missing data handling and discretization, a flexible graphical interface for probabilistic inference on the constructed Bayesian network models (for Java enabled browsers), automatic prettyHyphen;printed layout for the networks, exportation of the models, and analysis of the importance of the derived dependencies. In this paper we discuss both the theoretical design principles underlying the B-Course tool, and the pragmatic methods adopted in the implementation of the software.
176 citations
29 May 2002
TL;DR: EDUCO is a system that tries to bring in the sense of other users in a collaborative learning environment by making the other users and their the navigation visible to everyone else in the environment in real-time.
Abstract: Web-based learning is primarily a lonesome activity, even when it involves working in groups. This is due to the fact that the majority of web-based learning relies on asynchronous forms of interacting with other people. In most of the cases, the chat discussion is the only form of synchronous interaction that adds to the feeling that there are other people present in the environment. EDUCO is a system that tries to bring in the sense of other users in a collaborative learning environment by making the other users and their the navigation visible to everyone else in the environment in real-time. The paper describes EDUCO and presents the first empirical evaluation as EDUCO was used in a university course.
46 citations
TL;DR: It is shown how ethnographically based research can benefit the innovation of product concepts by demonstrating that qualitative user data can be successfully utilized in designing for everyday activities of largely neglected user groups like the elderly.
Abstract: Academic research in mobile and ubiquitous computing has been mainly technology-driven There is not enough understanding on what everyday needs are related to future mobile and ubiqitous computing In this paper we will demonstrate that qualitative user data can be successfully utilized in designing for everyday activities of largely neglected user groups like the elderly We will show how ethnographically based research can benefit the innovation of product concepts
29 citations
01 Jan 2002
TL;DR: Contrary to the research hypothesis and the common wisdom in the research area, the data gathered showed that making other users’ navigation visible did not have an effect on navigation in this experiment.
Abstract: EDUCO is a system for collaborative learning that uses real-time direct social navigation. Social navigation means making the navigation of other users visible to everyone else in the system. The paper discusses the social navigation features of EDUCO and reports empirical results regarding the collaborative behaviour of the students in a university-level Web-course. Contrary to our research hypothesis and the common wisdom in the research area, the data gathered showed that making other users’ navigation visible did not have an effect on navigation in this experiment.
15 citations
TL;DR: It is shown that QHPM is capable of finding the susceptibility loci, even when there is strong allelic heterogeneity and environmental effects in the disease models, and has good power to localize the genes even with unselected individuals.
Abstract: Previously, we have presented a data mining-based algorithmic approach to genetic association analysis, Haplotype Pattern Mining. We have now extended the approach with the possibility of analysing quantitative traits and utilising covariates. This is accomplished by using a linear model for measuring association. We present results with the extended version, QHPM, with simulated quantitative trait data. One data set was simulated with the population simulator package Populus, and another was obtained from GAW12. In the former, there were 2–3 underlying susceptibility genes for a trait, each with several ancestral disease mutations, and 1 or 2 environmental components. We show that QHPM is capable of finding the susceptibility loci, even when there is strong allelic heterogeneity and environmental effects in the disease models. The power of finding quantitative trait loci is dependent on the ascertainment scheme of the data: collecting the study subjects from both ends of the quantitative trait distribution is more effective than using unselected individuals or individuals ascertained based on disease status, but QHPM has good power to localize the genes even with unselected individuals. Comparison with quantitative trait TDT (QTDT) showed that QHPM has better localization accuracy when the gene effect is weak.
14 citations
TL;DR: It is argued that because of the economics of copying on the Internet it is not a sound strategy to use legal actions to remove any circumventing information from the internet, so the only working strategy seems to be to implement a DRM‐system, which can be updated without user intervention after the security is breached.
Abstract: Organized transnational political and technological activism - here referred to as transnational advocacy networks - has an increasingly strong role in giving images of how one should behave and what to consume. This article analyses transnational advocacy networks that oppose digital rights management (DRM) systems and related regulations. We suggest the potential impact of this activity to the consumption of content products. We start with defining and describing the most relevant advocacy networks. We provide the characterization of existing organizations and their work both the United States and Europe. Then, we discuss four case studies where media companies have experimented with different strategies against DRM circumvention initiated and endorsed by transnational advocacy networks Our argument is that because of the economics of copying on the Internet it is not a sound strategy to use legal actions to remove any circumventing information from the internet. Any circumvention information published on the Internet will be mirrored out of the reach of legal enforcement mechanisms. So far, the only working strategy seems to be to implement a DRM-system, which can be updated without user intervention after the security is breached. This might be also the most efficient way to control the impact of transnational advocacy networks opposing DRM systems.
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6 citations
20 Oct 2002
TL;DR: The extension of Kolmogorov's great ideas to probability model classes turns out to add a new chapter to the MDL theory, which also provides an alternative approach to Shannon's rate-distortion theory.
Abstract: This work was inspired by the paper of Vereshchagin and Vitanyi, where Kolmogorov's unpublished work on his structure function and the associated minimal sufficient statistics decomposition in the algorithmic theory of information is studied. The extension of Kolmogorov's great ideas to probability model classes turns out to add a new chapter to the MDL theory, which also provides an alternative approach to Shannon's rate-distortion theory.
5 citations
03 Dec 2002
TL;DR: EDUCO is a system for student-centred learning that every participant can see everyone else in the system and their navigational steps, so that the feeling of student companions taking part in the same tasks is increased.
Abstract: Student-centred learning can be used in Web-courses to increase student activity, motivation and commitment. EDUCO is a system for student-centred learning, both for the learners and the teachers. Students can use EDUCO within a standard Web-browser to navigate towards useful information and Web-resources gathered into the system. The key issue is that every participant can see everyone else in the system and their navigational steps, so that the feeling of student companions taking part in the same tasks is increased. The implications of this type of social navigation are discussed along with the description of the system itself.
3 citations
02 Jun 2002
TL;DR: The paper describes the system and discusses the generation of profiles and recommendations in EDUCO, a system for collaborative web-based learning that could benefit from dynamic profiling as well as active recommendations for the students working in the learning environment.
Abstract: EDUCO is system for collaborative web-based learning. Collaboration is enabled by real-time social navigation and support for social interaction via synchronous and asynchronous discussions. However, the system and the use of the system in collaborative learning could benefit from dynamic profiling as well as active recommendations for the students working in the learning environment. The paper describes the system and discusses the generation of profiles and recommendations.
01 Jan 2002
TL;DR: EDUFORM, an adaptive questionnaire designed for profiling students in various educational contexts, is introduced to build a probabilistic model from previously gathered data, and use it for profiling other people more efficiently.
Abstract: In this paper we introduce EDUFORM, an adaptive questionnaire designed for profiling students in various educational contexts. The idea is to build a probabilistic model from previously gathered data, and use it for profiling other people more efficiently. EDUFORM selects the questions presented to each individual adaptively in order to minimize the number of answers needed for reliable prediction of the profile. Empirical evaluations suggest that 85-90% accuracy can be achieved, while the number of questions is reduced by 30-50%.
01 Jan 2002
01 Jun 2002
TL;DR: The preliminary results show that some of the features used in this real time on- line collaboration tool can be directly applied to a wider context of modern computer-based learning environments.
Abstract: This paper describes the design and implementation of a real time on- line collaboration tool, EDUCO. The main focus is to demonstrate how the tool is applied to a real life on-line distance-education course, discuss the preliminary research findings of qualitative empirical study, and propose directions for future work and implications. The preliminary results show that some of the features used in this tool can be directly applied to a wider context of modern computer-based learning environments.