Asymmetric and adaptive conference systems for enabling computer supported mobile activities [Elektronische Ressource] / by Luiz Manoel Alves dos Santos

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• Publié par: technischen_universitat_darmstadt
• Publié le: 01 janvier 2003
• Nombre de lectures: 16
• Langue: English
• Poids de l'ouvrage: 2 Mo

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Asymmetric and Adaptive Conference Systems
for Enabling Computer-Supported Mobile Activities


by
Luiz Manoel Alves dos Santos, M.Sc.
from Ribeirão Preto, Brazil


Dissertation
Accepted by the Department of Computer Science
in partial fulfilment of the requirements for the degree of
Doktor-Ingenieur (Dr.-Ing.)


at the
Technische Universität Darmstadt






Supervisor: Professor Dr.-Ing. José L. Encarnação
Technische Universität Darmstadt, Germany

Co-Referees: Professor Dr.-Ing. Markus Groß
Eidgenössische Technische Hochschule Zürich, Switzerland
Professor Dr.-Ing. Adérito F. Marcos
Universidade do Minho, Portugal




Date of Delivery: April 16, 2003
Date of Oral Examination: May 28, 2003


Hochschulkennziffer D17
Darmstädter Dissertation 2003


Preface
This work was conducted at the Darmstadt University of Technology, essentially between
1998 and 2002. Before and during this period, I was working at the INI-GraphicsNet,
Darmstadt, first in the Zentrum für Graphische Datenverarbeitung e.V., and then later at the
Fraunhofer-Institut für Graphische Datenverarbeitung (IGD), as a researcher. This thesis
addresses the investigations and results achieved during my work at these organizations.
My initial development projects in the area of mobile computing were very challenging due
to the immense constraints posed by the then incipient hardware and wireless network
infrastructures, and similarly overwhelming due to the desire to employ those fascinating
appliances by all means possible. The endeavour to keep the respective application systems
in a course of continuous improvement (i.e., with richer media presentation and
“interactiveness”), and at the same astonishing pace as the technological evolutions, was both
demanding and rewarding; however, it turned out to be a questionable procedure. After
several prototype demonstrations and observations, there came a turning point, following the
acknowledgement that, for application cases involving user mobility, the supporting tool is
appraised significantly on the basis of its adequacy for the usage conditions and its flexibility
to adapt to changing requirements and to any platform specification or resource availability.
The circumstances of a mobile use (e.g., outdoor, on the move, in confined places) require
new approaches in application system development and create a high demand for specialized,
task-oriented system features. Any service being offered has to be able to account for, adjust
itself, and be responsive to the increasing and unpredictable diversity of prospective users
and their usage environments. The achievement of this attribute is even more challenging
when the service should be a basis for a digitally mediated human-to-human communication
process involving all kinds of diversity between the individual partners and technical
arrangements.
In this thesis work, proposals and innovative solutions to these challenges have been
investigated and implemented, and are presented in this report. Some contributions of this
work are: an adaptive conference system for heterogeneous environments, tools to assess,
distribute, and respond to User Profiles at both the individual and collective level; adaptive,
flexible individual interaction modes and media that are nevertheless consistent for a
collaborative work; and mechanisms for remote awareness (of constraints) for structuring
interaction. However, above any technological advances, the major research challenge was
concerned with the human factor and the achievement of an effective integration of a
supporting tool in their daily activities and lives.

Stylistic Conventions
In this work, the central character is the user and, to some extent, the system designer, as
well. When referring to either one of them, the singular pronoun ‘he’ is used as a generic
term. This should not be taken to imply anything about the composition of any population;
whenever the masculine form (e.g., “he”) is used, the feminine form (e.g., “she”) is meant, as
well. For easy reading, all composed forms (“his/her”, “him/her”, “himself/herself”) will not
be used.
Trademarks
MS-DOS Windows, Windows 95, Windows 98, Windows NT, Windows 2000, NetMeeting,
and Microsoft are registered trademarks of Microsoft Corporation.
All other trademarks, which are mentioned a single time, are acknowledged in the text.


Acknowledgements
For the realization of this work, I owe my gratitude to several people, who in various ways
have accompanied and contributed to its achievement.
First, I would like to express my utmost gratefulness to Professor José Luis Encarnação, who,
with his insightfulness and view to the future, has oriented and encouraged me to start
exploring such new horizons of knowledge and has welcomed me at his (our) house, where
he gave me the opportunity to work with his group at the Fraunhofer-Institute für Graphische
Datenverarbeitung. He continuously provided me with his support and inestimable advice. I
would also like to thank both co-referees of this work, Professor Markus Groß from the
Eidgenössische Technische Hochschule Zürich, and Professor Adérito Marcos from the
Universidade do Minho, for their much appreciated comments on my work.
Many thanks to Professor Brisson for his invaluably supportive, stimulating words and
continued attention. Further, I would like to thank the colleagues from ZGDV and IGD,
particularly Rüdiger and Joachim, and all of the students who worked with me, for their
incentives and valuable contributions to the conclusion of this work. My appreciation goes as
well to Dana, who patiently helped me in reviewing this text.
I would like to thank the Deutscher Akademischer Austausch Dienst (DAAD) for the initial
financial support through a scholarship, and the INI-GraphicsNet where I have been working
during the time of my research.
I am most grateful to all those colleagues and friends who, during my time at the IGD and in
Germany, have provided me with their much-enjoyed companionship and an intense belief in
humankind above all social and working challenges.
The solemnity of the moment compels me to formally express my profound gratitude to my
beloved family and dearest friends for their friendship, teaching, and motivation, not only in
pursuing my career, but also throughout my life.

















To my beloved parents




Table of Contents


CHAPTER 1: INTRODUCTION.................................................................................................... 6
1.1 A NEW APPROACH TO THE DEVELOPMENT OF COMPUTER SERVICES......................................... 6
1.2 MOTIVATION AND AIMS OF THIS DISSERTATION......................................................................... 7
1.3 BACKGROUND AND RESEARCH THEMES..................................................................................... 8
1.3.1 Research themes and position of this work........................................................................ 8
1.3.2 Resource awareness and adaptation ................................................................................... 9
1.3.3 Co-operative work with mobility 11
1.3.4 Interaction on the move 12
1.4 RESEARCH CONTRIBUTIONS ..................................................................................................... 13
1.5 SUMMARY ................................................................................................................................14
CHAPTER 2: MOBILE COMPUTING AND ITS TECHNOLOGICAL IMPLICATIONS .. 15
2.1 COMPUTER-SUPPORTED MOBILE ACTIVITIES ........................................................................... 15
2.2 SYMBIOSIS OF TECHNOLOGIES FOR SUPPORTING MOBILITY..................................................... 16
2.3 RESOURCES FOR MOBILE COMPUTING...................................................................................... 17
2.3.1 Mobile terminals .............................................................................................................. 17
2.3.2 Wireless communication network.................................................................................... 19
2.3.3 Appliances for context-awareness 24
2.3.4 Power supply and autonomy ............................................................................................ 25
2.3.5 Security ............................................................................................................................ 26
2.3.6 Social acceptability and personal concerns...................................................................... 26
2.4 CLOSING WORDS ...................................................................................................................... 26
CHAPTER 3: DATA AND SERVICE ARCHITECTURES FOR MOBILE COMPUTING.. 28
3.1 INTRODUCTION ................................................................