45 research outputs found
Forward Error Correction applied to JPEG-XS codestreams
JPEG-XS offers low complexity image compression for applications with
constrained but reasonable bit-rate, and low latency. Our paper explores the
deployment of JPEG-XS on lossy packet networks. To preserve low latency,
Forward Error Correction (FEC) is envisioned as the protection mechanism of
interest. Despite the JPEG-XS codestream is not scalable in essence, we observe
that the loss of a codestream fraction impacts the decoded image quality
differently, depending on whether this codestream fraction corresponds to
codestream headers, to coefficients significance information, or to low/high
frequency data, respectively. Hence, we propose a rate-distortion optimal
unequal error protection scheme that adapts the redundancy level of
Reed-Solomon codes according to the rate of channel losses and the type of
information protected by the code. Our experiments demonstrate that, at 5% loss
rates, it reduces the Mean Squared Error by up to 92% and 65%, compared to a
transmission without and with optimal but equal protection, respectively
Web Caching and Prefetching with Cyclic Model Analysis of Web Object Sequences
Web caching is the process in which web objects are temporarily stored to reduce bandwidth consumption, server load and latency. Web prefetching is the process of fetching web objects from the server before they are actually requested by the client. Integration of caching and prefetching can be very beneficial as the two techniques can support each other. By implementing this integrated scheme in a client-side proxy, the perceived latency can be reduced for not one but many users. In this paper, we propose a new integrated caching and prefetching policy called the WCP-CMA which makes use of a profit-driven caching policy that takes into account the periodicity and cyclic behaviour of the web access sequences for deriving prefetching rules. Our experimental results have shown a 10%-15% increase in the hit ratios of the cached objects and 5%-10% decrease in delay compared to the existing schem
Verbesserung der Dateiverarbeitungskette in Betriebssystemen durch Nutzung der Skalierbarkeit moderner Kompressionsverfahren
ï»żMotivated by the current challenges in the field of computerized
processing of multimedia information, this work contributes to the field of
research on data processing and file management within computer systems. It
presents novel techniques that enhance existing file- and operating systems
by utilizing the scalability of modern media formats.
For this purpose, the compression formats JPEG 2000 and H.264 SVC will be
presented with a focus on how they achieve scalability. An analysis of the
limiting hard- and software components in a computer system for the
application area is presented. In particular, the restrictions of the
utilized storage-devices, data interfaces and file systems are laid out and
workarounds to compensate the performance bottlenecks are depicted.
According to the observation that compensating the defiles requires extra
efforts, new solution statements utilizing scalable media are derived and
examined, subsequently.
The present work reveals new concepts for managing scalable media files
comprising a new rights management as well as a use-case-optimized storage
technique. The rights management allows for granting access to certain
parts of a file by which the scalability of the media files can be
exploited in a way that users get access to various variants depending on
their access rights. The use-case-optimized storage technique increases the
throughput of hard disk drives when the subsequent access pattern to the
media content is known a-priori.
In addition, enhancements for existing data workflows are proposed by
taking advantage of scalable media. Based on the Substitution Strategy,
where missing data from a scalable file is compensated, a real-time capable
procedure for reading files is shown. Using this strategy, image-sequences
comprising a video can be shown at a given frame rate without interruptions
caused by insufficient throughput of the storage device or low-speed
interfaces used to connect the storage device. Adapted caching-strategies
facilitate an increase of images residing in cache compared to
non-scalable-variants. Additionally, a concept called Parameterizable
File-Access is introduced which allows users to request a certain variant
of a scalable file directly from the file system by adding side-information
to a virtual file name.Motiviert durch die aktuellen Herausforderungen im Bereich der
computergestuÌtzten Bearbeitung vom Multimediadaten, leistet die
vorliegende Arbeit einen Beitrag zum Forschungsgebiet der Datenverarbeitung
und Dateiverwaltung innerhalb von Computersystemen durch neuartige
Verfahren zur Nutzung skalierbarer Medien unter Verwendung vorhandener
Datei- und Betriebssysteme.
Hierzu werden die Kompressionsformate JPEG 2000 und H.264 SVC vorgestellt
und gezeigt, wie die Eigenschaft der Skalierbarkeit innerhalb der
verschiedenen Verfahren erreicht wird. Es folgt eine Analyse der
limitierenden Hard- und Softwarekomponenten in einem Computersystem fuÌr
das o.g. Einsatzgebiet. Ausgehend vom hohen Aufwand zur Kompensation der
LeistungsengpaÌsse werden anschlieĂend neue LoÌsungsansaÌtze unter
Nutzung skalierbarer Medienformate abgeleitet, die nachfolgend untersucht
werden.
Die vorliegende Arbeit zeigt hierzu neue Konzepte zur Verwaltung
skalierbarer Mediendaten, die durch ein neues Rechtemanagement sowie durch
eine speicheradaptive Ablagestrategie abgedeckt werden. Das
Rechtemanagement erlaubt die Vergabe von Zugriffsrechten auf verschiedene
Abschnitte einer Datei, wodurch die Skalierbarkeit der Medien derart
abgebildet werden kann, dass verschiedene Benutzer unterschiedliche
Varianten einer Datei angezeigt bekommen. Die speicheradaptive
Ablagestrategie erreicht Durchsatzsteigerungen der verwendeten
DatentraÌger, wenn das spaÌtere Zugriffsverhalten auf die gespeicherten
Medien vorab bekannt ist.
Weiter werden Verbesserungen der VerarbeitungsablaÌufe unter Ausnutzung
skalierbarer Medien gezeigt. Auf Basis der entwickelten
Substitutionsmethode zur Kompensation fehlender Daten einer skalierbaren
Datei wird eine echtzeitfaÌhige Einlesestrategie vorgestellt, die
unzureichende Durchsatzraten von Speichermedien bzw. langsamen
Schnittstellen derart kompensieren kann, dass eine unterbrechungsfreie
Ausspielung von Bildsequenzen bei einer vorgegebenen Bildwiederholrate
gewaÌhrleistet werden kann. Angepasste Cache-Strategien ermoÌglichen eine
Steigerung der im Cache vorhaltbaren Einzelbilder im Vergleich zu nicht
skalierbaren Varianten. DaruÌber hinaus wird das Konzept eines
parametrisierbaren Dateiaufrufes eingefuÌhrt, wodurch mittels
Zusatzinformationen im virtuellen Dateinamen eine gewuÌnschte Variante
einer skalierbaren Datei vom Datenspeicher angefragt werden kann
Verbesserung der Dateiverarbeitungskette in Betriebssystemen durch Nutzung der Skalierbarkeit moderner Kompressionsverfahren
ï»żMotivated by the current challenges in the field of computerized
processing of multimedia information, this work contributes to the field of
research on data processing and file management within computer systems. It
presents novel techniques that enhance existing file- and operating systems
by utilizing the scalability of modern media formats.
For this purpose, the compression formats JPEG 2000 and H.264 SVC will be
presented with a focus on how they achieve scalability. An analysis of the
limiting hard- and software components in a computer system for the
application area is presented. In particular, the restrictions of the
utilized storage-devices, data interfaces and file systems are laid out and
workarounds to compensate the performance bottlenecks are depicted.
According to the observation that compensating the defiles requires extra
efforts, new solution statements utilizing scalable media are derived and
examined, subsequently.
The present work reveals new concepts for managing scalable media files
comprising a new rights management as well as a use-case-optimized storage
technique. The rights management allows for granting access to certain
parts of a file by which the scalability of the media files can be
exploited in a way that users get access to various variants depending on
their access rights. The use-case-optimized storage technique increases the
throughput of hard disk drives when the subsequent access pattern to the
media content is known a-priori.
In addition, enhancements for existing data workflows are proposed by
taking advantage of scalable media. Based on the Substitution Strategy,
where missing data from a scalable file is compensated, a real-time capable
procedure for reading files is shown. Using this strategy, image-sequences
comprising a video can be shown at a given frame rate without interruptions
caused by insufficient throughput of the storage device or low-speed
interfaces used to connect the storage device. Adapted caching-strategies
facilitate an increase of images residing in cache compared to
non-scalable-variants. Additionally, a concept called Parameterizable
File-Access is introduced which allows users to request a certain variant
of a scalable file directly from the file system by adding side-information
to a virtual file name.Motiviert durch die aktuellen Herausforderungen im Bereich der
computergestuÌtzten Bearbeitung vom Multimediadaten, leistet die
vorliegende Arbeit einen Beitrag zum Forschungsgebiet der Datenverarbeitung
und Dateiverwaltung innerhalb von Computersystemen durch neuartige
Verfahren zur Nutzung skalierbarer Medien unter Verwendung vorhandener
Datei- und Betriebssysteme.
Hierzu werden die Kompressionsformate JPEG 2000 und H.264 SVC vorgestellt
und gezeigt, wie die Eigenschaft der Skalierbarkeit innerhalb der
verschiedenen Verfahren erreicht wird. Es folgt eine Analyse der
limitierenden Hard- und Softwarekomponenten in einem Computersystem fuÌr
das o.g. Einsatzgebiet. Ausgehend vom hohen Aufwand zur Kompensation der
LeistungsengpaÌsse werden anschlieĂend neue LoÌsungsansaÌtze unter
Nutzung skalierbarer Medienformate abgeleitet, die nachfolgend untersucht
werden.
Die vorliegende Arbeit zeigt hierzu neue Konzepte zur Verwaltung
skalierbarer Mediendaten, die durch ein neues Rechtemanagement sowie durch
eine speicheradaptive Ablagestrategie abgedeckt werden. Das
Rechtemanagement erlaubt die Vergabe von Zugriffsrechten auf verschiedene
Abschnitte einer Datei, wodurch die Skalierbarkeit der Medien derart
abgebildet werden kann, dass verschiedene Benutzer unterschiedliche
Varianten einer Datei angezeigt bekommen. Die speicheradaptive
Ablagestrategie erreicht Durchsatzsteigerungen der verwendeten
DatentraÌger, wenn das spaÌtere Zugriffsverhalten auf die gespeicherten
Medien vorab bekannt ist.
Weiter werden Verbesserungen der VerarbeitungsablaÌufe unter Ausnutzung
skalierbarer Medien gezeigt. Auf Basis der entwickelten
Substitutionsmethode zur Kompensation fehlender Daten einer skalierbaren
Datei wird eine echtzeitfaÌhige Einlesestrategie vorgestellt, die
unzureichende Durchsatzraten von Speichermedien bzw. langsamen
Schnittstellen derart kompensieren kann, dass eine unterbrechungsfreie
Ausspielung von Bildsequenzen bei einer vorgegebenen Bildwiederholrate
gewaÌhrleistet werden kann. Angepasste Cache-Strategien ermoÌglichen eine
Steigerung der im Cache vorhaltbaren Einzelbilder im Vergleich zu nicht
skalierbaren Varianten. DaruÌber hinaus wird das Konzept eines
parametrisierbaren Dateiaufrufes eingefuÌhrt, wodurch mittels
Zusatzinformationen im virtuellen Dateinamen eine gewuÌnschte Variante
einer skalierbaren Datei vom Datenspeicher angefragt werden kann
Multimedia
The nowadays ubiquitous and effortless digital data capture and processing capabilities offered by the majority of devices, lead to an unprecedented penetration of multimedia content in our everyday life. To make the most of this phenomenon, the rapidly increasing volume and usage of digitised content requires constant re-evaluation and adaptation of multimedia methodologies, in order to meet the relentless change of requirements from both the user and system perspectives. Advances in Multimedia provides readers with an overview of the ever-growing field of multimedia by bringing together various research studies and surveys from different subfields that point out such important aspects. Some of the main topics that this book deals with include: multimedia management in peer-to-peer structures & wireless networks, security characteristics in multimedia, semantic gap bridging for multimedia content and novel multimedia applications
Granite: A scientific database model and implementation
The principal goal of this research was to develop a formal comprehensive model for representing highly complex scientific data. An effective model should provide a conceptually uniform way to represent data and it should serve as a framework for the implementation of an efficient and easy-to-use software environment that implements the model. The dissertation work presented here describes such a model and its contributions to the field of scientific databases. In particular, the Granite model encompasses a wide variety of datatypes used across many disciplines of science and engineering today. It is unique in that it defines dataset geometry and topology as separate conceptual components of a scientific dataset. We provide a novel classification of geometries and topologies that has important practical implications for a scientific database implementation. The Granite model also offers integrated support for multiresolution and adaptive resolution data. Many of these ideas have been addressed by others, but no one has tried to bring them all together in a single comprehensive model.
The datasource portion of the Granite model offers several further contributions. In addition to providing a convenient conceptual view of rectilinear data, it also supports multisource data. Data can be taken from various sources and combined into a unified view.
The rod storage model is an abstraction for file storage that has proven an effective platform upon which to develop efficient access to storage. Our spatial prefetching technique is built upon the rod storage model, and demonstrates very significant improvement in access to scientific datasets, and also allows machines to access data that is far too large to fit in main memory. These improvements bring the extremely large datasets now being generated in many scientific fields into the realm of tractability for the ordinary researcher.
We validated the feasibility and viability of the model by implementing a significant portion of it in the Granite system. Extensive performance evaluations of the implementation indicate that the features of the model can be provided in a user-friendly manner with an efficiency that is competitive with more ad hoc systems and more specialized application specific solutions
The Design of a System Architecture for Mobile Multimedia Computers
This chapter discusses the system architecture of a portable computer, called Mobile Digital Companion, which provides support for handling multimedia applications energy efficiently. Because battery life is limited and battery weight is an important factor for the size and the weight of the Mobile Digital Companion, energy management plays a crucial role in the architecture. As the Companion must remain usable in a variety of environments, it has to be flexible and adaptable to various operating conditions. The Mobile Digital Companion has an unconventional architecture that saves energy by using system decomposition at different levels of the architecture and exploits locality of reference with dedicated, optimised modules. The approach is based on dedicated functionality and the extensive use of energy reduction techniques at all levels of system design. The system has an architecture with a general-purpose processor accompanied by a set of heterogeneous autonomous programmable modules, each providing an energy efficient implementation of dedicated tasks. A reconfigurable internal communication network switch exploits locality of reference and eliminates wasteful data copies
Management of spatial data for visualization on mobile devices
Vector-based mapping is emerging as a preferred format in Location-based
Services(LBS), because it can deliver an up-to-date and interactive map visualization.
The Progressive Transmission(PT) technique has been developed to
enable the ecient transmission of vector data over the internet by delivering
various incremental levels of detail(LoD). However, it is still challenging to apply
this technique in a mobile context due to many inherent limitations of mobile
devices, such as small screen size, slow processors and limited memory. Taking
account of these limitations, PT has been extended by developing a framework of
ecient data management for the visualization of spatial data on mobile devices.
A data generalization framework is proposed and implemented in a software
application. This application can signicantly reduce the volume of data for
transmission and enable quick access to a simplied version of data while preserving
appropriate visualization quality. Using volunteered geographic information
as a case-study, the framework shows
exibility in delivering up-to-date spatial
information from dynamic data sources.
Three models of PT are designed and implemented to transmit the additional
LoD renements: a full scale PT as an inverse of generalisation, a viewdependent
PT, and a heuristic optimised view-dependent PT. These models are
evaluated with user trials and application examples. The heuristic optimised
view-dependent PT has shown a signicant enhancement over the traditional PT
in terms of bandwidth-saving and smoothness of transitions.
A parallel data management strategy associated with three corresponding
algorithms has been developed to handle LoD spatial data on mobile clients.
This strategy enables the map rendering to be performed in parallel with a process
which retrieves the data for the next map location the user will require. A viewdependent
approach has been integrated to monitor the volume of each LoD for
visible area. The demonstration of a
exible rendering style shows its potential
use in visualizing dynamic geoprocessed data. Future work may extend this
to integrate topological constraints and semantic constraints for enhancing the
vector map visualization
Proceedings of the 5th International Workshop on Reconfigurable Communication-centric Systems on Chip 2010 - ReCoSoC\u2710 - May 17-19, 2010 Karlsruhe, Germany. (KIT Scientific Reports ; 7551)
ReCoSoC is intended to be a periodic annual meeting to expose and discuss gathered expertise as well as state of the art research around SoC related topics through plenary invited papers and posters. The workshop aims to provide a prospective view of tomorrow\u27s challenges in the multibillion transistor era, taking into account the emerging techniques and architectures exploring the synergy between flexible on-chip communication and system reconfigurability