5,621 research outputs found
Investigation Report on Universal Multimedia Access
Universal Multimedia Access (UMA) refers to the ability to access by any user to the desired multimedia content(s) over any type of network with any device from anywhere and anytime. UMA is a key framework for multimedia content delivery service using metadata. This investigation report analyzes the state-of-the-art technologies in UMA and tries to identify the key issues of UMA. The state-of-the-art in multimedia content adaptation, an overview of the standards that supports the UMA framework, potential privacy problems in UMA systems and some new UMA applications are presented in this report. This report also provides challenges that still remain to be resolved in UMA to make clear the potential key problems in UMA and determine which ones to solve
Output constraints in multimedia database systems
Zusammenfassung
Semantische Fehler treten bei jeder Art von Datenverwaltung auf. Herkömmliche
Datenbanksysteme verwenden eine IntegritÀtskontrolle, um semantische Fehler zu
vermeiden. Um die IntegritÀt der Daten zu gewÀhrleisten werden IntegritÀtsregeln
benutzt. Diese Regeln können allerdings nur die Konsistenz einfach
strukturierter Daten ĂŒberprĂŒfen.
Multimedia Datenbanksystem verwalten neben einfachen alphanumerischen Daten auch
komplexe Mediendaten wie Videos. Um die Konsistenz dieser Daten zu sichern,
bedarf es einer erheblichen Erweiterung des bestehenden IntegritÀtskonzeptes.
Dabei muss besonders auf die konsistente Datenausgabe geachtet werden. Im
Gegensatz zu alphanumerischen Daten können Mediendaten wÀhrend der Ausgabe
verfÀlscht werden. Dieser Fall kann eintreten, wenn eine geforderte
DatenqualitÀt bei der Ausgabe nicht erreicht werden kann oder wenn
Synchronisationsbedingungen
zwischen Medienobjekten nicht eingehalten werden können. Es besteht daher die
Notwendigkeit, Ouptut Constraints einzufĂŒhren. Mit ihrer Hilfe kann definiert
werden, wann die Ausgabe von Mediendaten semantisch korrekt ist. Das
Datenbanksystem kann diese Bedingungen ĂŒberprĂŒfen und so gewĂ€hrleisten, dass der
Nutzer semantisch einwandfreie Daten erhÀlt.
In dieser Arbeit werden alle Aspekte betrachtet, die notwendig sind, um
Ausgabebedingungen in ein Multimedia Datenbanksystem zu integrieren. Im
einzelnen werden die Modellierung der Bedingungen, deren datenbankinterne
ReprĂ€sentation sowie die BedingungsĂŒberprĂŒfung betrachtet.
FĂŒr die Bedingungsmodellierung wird eine Constraint Language auf Basis der
PrĂ€dikatenlogik eingefĂŒhrt. Um die Definition von zeitlichen und rĂ€umlichen
Synchronisationen zu ermöglichen, verwenden wir Allen-Relationen. FĂŒr die
effiziente ĂberprĂŒfung der Ausgabebedingungen mĂŒssen diese aus der
Spezifikationssprache in eine datenbankinterne Darstellung ĂŒberfĂŒhrt werden.
FĂŒr die datenbankinterne Darstellung werden Difference Constraints verwendet.
Diese erlauben eine sehr effiziente BedingungsĂŒberprĂŒfung. Wir haben Algorithmen
entwickelt, die eine effiziente ĂberprĂŒfung von Ausgabebedingungen erlauben und
dies anhand von Experimenten nachgewiesen. Neben der ĂberprĂŒfung der Bedingungen
mĂŒssen Mediendaten so synchronisiert werden, dass dies den Ausgabebedingungen
entspricht. Wir haben dazu das Konzept des Output Schedules entwickelt. Dieser
wird aufgrund der definierten Ausgabebedingungen generiert.
Durch die Ausgabebedingungen, die in dieser Arbeit eingefĂŒhrt werden, werden
semantische Fehler bei der Verwaltung von Mediendaten erheblich reduziert. Die
Arbeit stellt daher einen Beitrag zur qualitativen Verbesserung der Verwaltung
von Mediendaten dar.Semantic errors exist as long as data are managed. Traditional database systems try to prevent this errors by proposing integrity
concepts for stored data. Integrity constraints are used to implement these integrity concepts. However, integrity constraints can only detect semantic errors in elementary data.
Multimedia database systems manage elementary data as well as complex media data, like videos. Considering these media data we need a much wider consistency concept as traditional database systems provide. Especially, data output of media data must be taken into account. In contrast to alphanumeric data the semantics of media data can be falsified during data output if data quality or
synchronization of data are not suitable. Thus, we need a concept for output constraints that allow for preventing semantic errors in case of data output. For integrating output constraints into a multimedia database system we have to consider modelling, representation and checking of output constraints.
For modelling output constraints we have introduced a constraint language which uses the same principles as traditional constraint languages. Our constraint specification language must support temporal and spatial synchronization constraints. However, it is desired to support both kinds of synchronization in almost the same manner. Therefore, we use Allen-Relations for defining temporal
synchronization constraints as well as for defining spatial synchronization constraints.
We need a database internal representation of output constraints that makes efficient constraint checking possible. The Allen-Relations used in the constraint language cannot be checked efficiently. However, difference constraints are a class of constraints that allows an very efficient checking. Therefore, we use difference constraints as database internal representation of output constraints.
As methods for checking consistency of output constraints we use an approach based on graph theory as well as an analytical approach. Both approaches require a constraint graph as data structure. For data output we need an output order that is adequate to the defined output constraints. This output schedule can be produced based on the output constraints.
With output constraints, proposed in this thesis, semantical correctness of media data considering the data output can be supported.Thus, the contribution of this work is an qualitative improvement of managing media data by database systems
Meta data to support context aware mobile applications
Published versio
New Frontiers in Universal Multimedia Access
Universal Multimedia Access (UMA) refers to the ability to access by any user to the desired multimedia content(s) over any type of network with any device from anywhere and anytime. UMA is a key framework for multimedia content delivery service using metadata. This report consists of three parts. The first part of this report analyzes the state-of-the-art technologies in UMA, identifies the key issues and gives what are the new challenges that still remain to be resolved in UMA. The key issues in UMA include the adaptation of multimedia contents to bridge the gap between content creation and consuming, standardized metadata description that facilitates the adaptation (e.g. MPEG-7, MPEG-21 DIA, CC/PP), and UMA system designing considering its target application. The second part introduces our approach towards these challenges; how to jointly adapt multimedia contents including different modalities and balance their presentation in an optimal way. A scheme for adapting audiovisual contents and its metadata (text) to any screen is proposed to provide the best experience in browsing the desired content. The adaptation process is modeled as an optimization problem of the total value of the content provided to the user. The total content value is optimized by jointly controlling the balance between video and metadata presentation, the transformation of the video content, and the amount of the metadata to be presented. Experimental results show that the proposed adaptation scheme enables users to browse audiovisual contents with their metadata optimized to the screen size of their devices. The last part reports some potential UMA applications especially focusing on a universal access application to TV news archives as an example
Ontologies for context-aware applications
Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 200
Architectural support for ubiquitous access to multimedia content
Tese de doutoramento. Engenharia Electrotécnica e de Computadores (TelecomunicaçÔes). Faculdade de Engenharia. Universidade do Porto. 200
Personalised trails and learner profiling within e-learning environments
This deliverable focuses on personalisation and personalised trails. We begin by introducing and defining the concepts of personalisation and personalised trails. Personalisation requires that a user profile be stored, and so we assess currently available standard profile schemas and discuss the requirements for a profile to support personalised learning. We then review techniques for providing personalisation and some systems that implement these techniques, and discuss some of the issues around evaluating personalisation systems. We look especially at the use of learning and cognitive styles to support personalised learning, and also consider personalisation in the field of mobile learning, which has a slightly different take on the subject, and in commercially available systems, where personalisation support is found to currently be only at quite a low level. We conclude with a summary of the lessons to be learned from our review of personalisation and personalised trails
Cuypers : a semi-automatic hypermedia generation system
The report describes the architecture of emph{Cuypers, a system supporting second and third generation Web-based multimedia. First generation Web-content encodes information in handwritten (HTML) Web pages. Second generation Web content generates HTML pages on demand, e.g. by filling in templates with content retrieved dynamically from a database or transformation of structured documents using style sheets (e.g. XSLT). Third generation Web pages will make use of rich markup (e.g. XML) along with metadata (e.g. RDF) schemes to make the content not only machine readable but also machine processable --- a necessary pre-requisite to the emph{Semantic Web. While text-based content on the Web is already rapidly approaching the third generation, multimedia content is still trying to catch up with second generation techniques. Multimedia document processing has a number of fundamentally different requirements from text which make it more difficult to incorporate within the document processing chain. In particular, multimedia transformation uses different document and presentation abstractions, its formatting rules cannot be based on text-flow, it requires feedback from the formatting back-end and is hard to describe in the functional style of current style languages. We state the requirements for second generation processing of multimedia and describe how these have been incorporated in our prototype multimedia document transformation environment, emph{Cuypers. The system overcomes a number of the restrictions of the text-flow based tool sets by integrating a number of conceptually distinct processing steps in a single runtime execution environment. We describe the need for these different processing steps and describe them in turn (semantic structure, communicative device, qualitative constraints, quantitative constraints, final form presentation), and illustrate our approach by means of an example. We conclude by discussing the models and techniques required for the creation of third generation multimedia content
Ubiquitous Computing
The aim of this book is to give a treatment of the actively developed domain of Ubiquitous computing. Originally proposed by Mark D. Weiser, the concept of Ubiquitous computing enables a real-time global sensing, context-aware informational retrieval, multi-modal interaction with the user and enhanced visualization capabilities. In effect, Ubiquitous computing environments give extremely new and futuristic abilities to look at and interact with our habitat at any time and from anywhere. In that domain, researchers are confronted with many foundational, technological and engineering issues which were not known before. Detailed cross-disciplinary coverage of these issues is really needed today for further progress and widening of application range. This book collects twelve original works of researchers from eleven countries, which are clustered into four sections: Foundations, Security and Privacy, Integration and Middleware, Practical Applications
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