A-2005-1 Paavo Arvola, Marko Junkkari, Timo Aalto and Jaana Kekäläinen,
Utilizing context in weighting of XML elements for information retrieval. April 2005.
Abstract.
A re-weighting method for elements in XML retrieval is proposed. The method is
based on the idea of using the ancestors of an element as a context: the better
context the element has - good interpreted as weighting score - the more its own
weight is increased in relevance scoring. Our basic weighting scheme is a tf*idf
modification based on BM25. We will also discuss the effects of tuning length
normalization on the size of retrieved elements, and the problem of overlapping
elements in XML evaluation.
Keywords: XML, structured documents, re-weighting, contextualization.
A-2005-2 Timo Niemi and Janne Jämsen,
Discovering of semantic associations. June 2005.
Abstract. In contemporary query languages
the user is responsible for the specification of navigation among semantically
related data. Because of the huge amount of data and complex structural relationships
among data in modern applications it is unrealistic to suppose that the user
could know completely the content and structure of available information. There
are several query languages whose idea is to facilitate navigation in unknown
structures of databases, e.g., a navigation path can contain unknown parts.
However the background assumption of these languages is that the user knows how
data are related to each other semantically in the structure at hand. So far
only little attention has been paid to how unknown semantic associations among
available data can be discovered. We address this problem in this paper. A
semantic association between two entities can be constructed if such a sequence
of relationships expressed explicitly in a database can be found that connects
these entities to each other. This sequence may contain several other entities
through which the original entities are connected to each other indirectly. We
introduce an expressive and declarative query language for discovering semantic
associations. In addition to discovering semantic associations between entities
given explicitly, our query language is able to discover semantic associations between
entities that are only known for some of their characteristics. Further, it
integrates the manipulation of semantic associations with the manipulation of
documents which may contain information on entities in semantic associations.
Because a semantic association may contain several relationships and entities,
the results of queries are represented on the basis of natural language in
order to facilitate correct interpretation by the user. We also categorize
several query types and give sample queries on them. These sample queries
demonstrate how also complex queries can be expressed compactly and intuitively
in our language.
Keywords: Semantic association, knowledge discovering, query language, document, XML.
A-2005-3 Kai Koskimies, Ludwik Kuzniarz, Jyrki Nummenmaa and Zheying Zhang
(eds.), Proceedings of the NWUML'2005: The 3rd Nordic Workshop on UML
and Software Modeling. August 2005.
pdf-file
A-2005-4 Timo Tossavainen, Virtual Reality and Posturography Applied to Postural
Control Research. October 2005.
Abstract.
This thesis describes design, development, and applications of an
integrated stimulation and measurement system for postural control research
based on virtual reality (VR) methods and force platform posturography. The
system exposes test subjects to immersive computer-generated environments intended
to disturb balance and measures the response using a force platform. Analysis is
carried out on stabilograms obtained from the force platform to determine the
outcome.
Our first experiments show that virtual environments affect balance and
that they can be designed to cause effects, such as leaning in different
directions, in test subjects. During the development, we compared the
head-mounted display (HMD) and CAVE at Tampere Virtual Reality Center for visual
stimulation. Test subjects were exposed to the same virtual environments using the two
displays and significant differences in the responses were found between HMD and
CAVE. The constructed VR posturography system was deployed in a laboratory in
the Hearing Center of Tampere University Central Hospital and tested on control
subjects and patients with diagnosed balance disorders. Responses of control
subjects and patients with Meniere's disease differed significantly
and provided good discrimination between the two groups. Finally, pattern
recognition methods were applied to summarize the differences in
measurements that are otherwise difficult to interpret.
The applications described in this thesis show that VR is a versatile and
effective visual stimulation method for use in postural control research. Many
of the experimental setups implemented multiple balance tests in sequence, all
using same hardware. VR posturography thus provided an easy way to quickly and
comprehensively characterize a test subject's postural stability.
Keywords. Virtual reality, posturography, postural control,
postural stability.
Ph.D. Dissertation.
A-2005-4 has appeared electronically as
Acta Electronica Universitatis Tamperensis, vol. 507.
A-2005-5 Tatiana Evreinova, Grigori Evreinov, and Roope Raisamo,
An alternative approach to
strengthening tactile memory in hearing impaired adults. September 2005.
Abstract.
Deaf and hearing-impaired people need special educational and
developmental tools to support their social inclusion. Research in
vibro-tactile pattern perception has shown that tactile memory could
be crucial aspect in coding and imaging semantic information to the
impaired. This paper describes a simple matching game designed to
facilitate learning 27 vibro-tactile composite patterns (tactons)
which can be produced with the Logitech tactile feedback mouse. Our
assumption was that a particular framework and game intrigue would induce a
player to mobilize the perceptive skills and deploy individual playing
tactics to recall the tactons when progressing through the game. The
performance of 10 subjects using soundproof headphones was investigated in terms
of the number of repetitions required to memorize and learn the
mono-frequency, bi-frequency and three-frequency tactons, and
selection time needed to match the tactons in the game script. The analysis of
the data collected indicated that the novice-to-expert transition was
significantly above chance when the results obtained in the first and
the last test sessions were statistically analyzed and compared.
There was also a significant difference between mean selection times needed
to match the composite patterns depending of their complexity in the
first and the last test sessions. Upon learning and training within game,
the tactons may be employed to assign alphabet characters or symbols to
communicate textual or symbolic information.
A-2005-6 Tatiana Evreinova, Alternative visualization of textual
information for people with sensory impairment. November 2005.
Abstract.
By virtue of lacking visual feedback or access to verbal communication, people
with a sensory impairment use alternative means for information imaging that
rely on residual senses. For this reason, a wide range of assistive hardware and
software came into the market to provide an efficient way of alternative
imaging, for instance, of textual information. Nevertheless, nearly one third of
these techniques were withdrawn from the market due to lack of use.
Recent innovations offer limited functionality and more often than not, the
low accuracy of the produced output hampers the use of assistive aids.
Designers should focus not on the technique itself, but on the optimal
combination of the intact modalities to provide the disabled user with efficient
access to textual information. One of the aims in the adequate use of assistive
aids is to shape appropriate modality-specific notions to mediate
communication with people having normal abilities. Implementation of the
novel assistive techniques may be based on diverse technologies employing
speech and speech-like signals, visual and vibro-tactile patterns, which can be
used to display unambiguously the semantics of the textual message in a case
when the environment has different constraints or the user has inferior
perceptive thresholds due to chronic disease. In such cases, the required
techniques should provide real-time or close to real time processing and
imaging of the textual information so that both ordinary users and people with
a sensory impairment would be able to use it autonomously without assistants
or interpreters.
The foremost purpose of this dissertation is to consider the latest assistive
technologies in order to suggest further improvements. Therefore, the summary
provides background for the research papers included and an analytical survey
of assistive methods/techniques. The problematic aspects affecting the use of
computer help for people having ocular pathology and hearing disorders is the
particular subject of our study. The considerations presented are intended for
the developers of advanced assistive user interfaces.
The empirical part of the dissertation consists of a collection of the assistive
aids which were designed to augment and expand access to the textual
information for people with a sensory impairment. The central idea of this
dissertation was blending signals of several modalities to reproduce distinct
cases of the recognizable spatial-temporal semantic constructions such as vibrotactile,
audio-tactile and color patterns within minimal array of the coding units
used for alternative imaging of textual information. Two prototypes of the
wearable assistive devices such as BlinkGlasses and TactilePointer and some
other software tools were designed to carry out empirical research in these
subjects. Eight research papers representing the main contribution of this
dissertation are introduced. Careful combination of the empirical research,
thorough evaluation and further analysis of the outcomes which the approaches
developed resulted in was the main principle for the completion of these
empirical studies.
A key question is whether people with a sensory impairment can take
advantage of the devices developed and if so, to what extent. How flexible the
use of assistive technologies will become and how powerful they are going to
be, will depend on the further development of the exploratory strategies
directed toward the improvement of the assistive aids.
Ph.D. Dissertation.
A-2005-6 has appeared electronically as
Acta Electronica Universitatis Tamperensis, vol. 478.
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