TY - THES A1 - Hanning, Tobias T1 - Vektorielle Mehrniveaupassung. Anwendungen in der Bildsegmentierung N2 - Die Anwendungen der vektoriellen Mehrniveaupassung in der Bildsegmentierung stehen in unmittelbarer Nachbarschaft zum verbreiteten Ansatz, Bilder mit Methoden der Variationsrechnung über einen Energieterm zu segmentieren. Beiden Verfahren ist gemeinsam, daß sie versuchen, das gegebene Bild durch stückweise stetige Funktionen zu approximieren. Die maximalen Teilmengen des Definitionsbereichs, auf denen die approximierende Funktion stetig ist, bilden dann die Segmente. Im Gegensatz zu dem in der Literatur häufig unter dem Schlagwort Mumford-Shah-Modell bekannten Energieminimierungsverfahren ist der Raum der Funktionen, mit denen das Bild approximiert wird, bei der vektoriellen Mehrniveaupassung ein endlicher Vektorraum. Ein weiterer Unterschied zu diesem Ansatz ist das System der erlaubten Mengen. Es werden nur Segmentierungen erlaubt, deren Segmente aus diesem Mengensystem sind. Die durch diese Einschränkung schlankere Theorie führt zu einer gesicherten Existenz einer optimalen Lösung des Segmentierungsproblems, die der gängigen Vorstellung einer Segmentierung genügt. Die Berechnung lokaler Optima ist algorithmisch innerhalb der Theorie umsetzbar. KW - Bildsegmentierung KW - Mumford-Shah-Funktional KW - Approximation KW - Vektorielle Mehrniveaupassung KW - Energieminimierung KW - stückweise stetige Approximation Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus-295 ER - TY - THES A1 - Kunze, Kai T1 - Compensating for On-Body Placement Effects in Activity Recognition T1 - Kompensation positionsbezogener Artefakte in Aktivitätserkennung N2 - This thesis investigates, how placement variations of electronic devices influence the possibility of using sensors integrated in those devices for context recognition. The vast majority of context recognition research assumes well defined, fixed sen- sor locations. Although this might be acceptable for some application domains (e.g. in an industrial setting), users, in general, will have a hard time coping with these limitations. If one needs to remember to carry dedicated sensors and to adjust their orientation from time to time, the activity recognition system is more distracting than helpful. How can we deal with device location and orientation changes to make context sensing mainstream? This thesis presents a systematic evaluation of device placement effects in context recognition. We first deal with detecting if a device is carried on the body or placed somewhere in the environ- ment. If the device is placed on the body, it is useful to know on which body part. We also address how to deal with sensors changing their position and their orientation during use. For each of these topics some highlights are given in the following. Regarding environmental placement, we introduce an active sampling ap- proach to infer symbolic object location. This approach requires only simple sensors (acceleration, sound) and no infrastructure setup. The method works for specific placements such as "on the couch", "in the desk drawer" as well as for general location classes, such as "closed wood compartment" or "open iron sur- face". In the experimental evaluation we reach a recognition accuracy of 90% and above over a total of over 1200 measurements from 35 specific locations (taken from 3 different rooms) and 12 abstract location classes. To derive the coarse device placement on the body, we present a method solely based on rotation and acceleration signals from the device. It works independent of the device orientation. The on-body placement recognition rate is around 80% over 4 min. of unconstrained motion data for the worst scenario and up to 90% over a 2 min. interval for the best scenario. We use over 30 hours of motion data for the analysis. Two special issues of device placement are orientation and displacement. This thesis proposes a set of heuristics that significantly increase the robustness of motion sensor-based activity recognition with respect to sen- sor displacement. We show how, within certain limits and with modest quality degradation, motion sensor-based activity recognition can be implemented in a displacement tolerant way. We evaluate our heuristics first on a set of synthetic lower arm motions which are well suited to illustrate the strengths and limits of our approach, then on an extended modes of locomotion problem (sensors on the upper leg) and finally on a set of exercises performed on various gym machines (sensors placed on the lower arm). In this example our heuristic raises the dis- placed recognition rate from 24% for a displaced accelerometer, which had 96% recognition when not displaced, to 82%. KW - Kontextbezogenes System KW - Mustererkennung KW - Aktivitätserkennung KW - positionsbezogener Effekte KW - sensor displacement KW - on-body KW - context recognition Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus-26114 ER - TY - THES A1 - Capco, Jose T1 - Real Closed * Rings T1 - Reelle abgeschlossene * Ringe N2 - In this dissertation I examine a definition of real closure of commutative unitary reduced rings. I also give a characterization of rings that are real closed in this context and how one is able to arrive to such a real closure. There are sufficient examples to help the reader get a feel for real closed * rings and the real closure * of commutative unitary rings. KW - real closed rings KW - real closure Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus-25915 ER - TY - INPR A1 - Kreitmeier, Wolfgang A1 - Linder, Tamas T1 - Entropy Density and Mismatch in High-Rate Scalar Quantization with Rényi Entropy Constraint N2 - Properties of scalar quantization with $r$th power distortion and constrained R\'enyi entropy of order $\alpha\in (0,1)$ are investigated. For an asymptotically (high-rate) optimal sequence of quantizers, the contribution to the R\'enyi entropy due to source values in a fixed interval is identified in terms of the "entropy density" of the quantizer sequence. This extends results related to the well-known point density concept in optimal fixed-rate quantization. A dual of the entropy density result quantifies the distortion contribution of a given interval to the overall distortion. The distortion loss resulting from a mismatch of source densities in the design of an asymptotically optimal sequence of quantizers is also determined. This extends Bucklew's fixed-rate ($\alpha=0$) and Gray \emph{et al.}'s variable-rate ($\alpha=1$)mismatch results to general values of the entropy order parameter $\alpha$ KW - Maßtheorie KW - Quantisierung KW - Entropie KW - Asymptotic quantization theory KW - distortion density KW - entropy density KW - quantizer mismatch KW - Rényi-entropy Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus-26132 N1 - This is a preprint of an article accepted for publication in the IEEE Transactions on Information Theory Journal, ISSN: 0018-9448. The original publication is available at http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=18 ER - TY - INPR A1 - Kreitmeier, Wolfgang T1 - Optimal quantization for uniform distributions on Cantor-like sets N2 - In this paper, the problem of optimal quantization is solved for uniform distributions on some higher dimensional, not necessarily self-similar $N-$adic Cantor-like sets. The optimal codebooks are determined and the optimal quantization error is calculated. The existence of the quantization dimension is characterized and it is shown that the quantization coefficient does not exist. The special case of self-similarity is also discussed. The conditions imposed are a separation property of the distribution and strict monotonicity of the first $N$ quantization error differences. Criteria for these conditions are proved and as special examples modified versions of classical fractal distributions are discussed. KW - Maßtheorie KW - Quantisierung KW - Iteriertes Funktionensystem KW - Fraktale Dimension KW - optimal quantization KW - quantization dimension KW - quantization coefficient KW - self-similar probabilities Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus-12449 ER - TY - INPR A1 - Kreitmeier, Wolfgang T1 - Optimal Quantization for Dyadic Homogeneous Cantor Distributions N2 - For a large class of dyadic homogeneous Cantor distributions in \mathbb{R}, which are not necessarily self-similar, we determine the optimal quantizers, give a characterization for the existence of the quantization dimension, and show the non-existence of the quantization coefficient. The class contains all self-similar dyadic Cantor distributions, with contraction factor less than or equal to \frac{1}{3}. For these distributions we calculate the quantization errors explicitly. KW - Maßtheorie KW - Fraktale Dimension KW - Iteriertes Funktionensystem KW - Cantor-Menge KW - Hausdorff-Dimension KW - Hausdorff-Maß KW - Quantization KW - homogeneous Cantor measures KW - Quantization dimension KW - Quantization coefficient Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus-3845 N1 - Die Endfassung des Artikels kann beim Verfasser angefordert werden. Kontaktinformation: opus@uni-passau.de ER - TY - INPR A1 - Kreitmeier, Wolfgang T1 - Asymptotic order of quantization for Cantor distributions in terms of Euler characteristic, Hausdorff and Packing measure N2 - For homogeneous one-dimensional Cantor sets, which are not necessarily self-similar, we show under some restrictions that the Euler exponent equals the quantization dimension of the uniform distribution on these Cantor sets. Moreover for a special sub-class of these sets we present a linkage between the Hausdorff and the Packing measure of these sets and the high-rate asymptotics of the quantization error. KW - Maßtheorie KW - Fraktale Dimension KW - Iteriertes Funktionensystem KW - Cantor-Menge KW - Hausdorff-Dimension KW - Hausdorff-Maß KW - Homogeneous Cantor set KW - Euler characteristic KW - Euler exponent KW - quantization dimension KW - quantization coefficient KW - Hausdorff dimension Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus-7374 N1 - Die Endfassung des Artikels kann beim Verfasser angefordert werden. Kontaktinformation: opus@uni-passau.de ER - TY - INPR A1 - Kreitmeier, Wolfgang T1 - Optimal quantization of probabilities concentrated on small balls N2 - We consider probability distributions which are uniformly distributed on a disjoint union of balls with equal radius. For small enough radius the optimal quantization error is calculated explicitly in terms of the ball centroids. We apply the results to special self-similar measures. KW - Maßtheorie KW - Quantisierung KW - Iteriertes Funktionensystem KW - Schwerpunkt KW - optimal quantization KW - centroid KW - self-similar probabilities Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus-12010 ER - TY - THES A1 - Guppenberger, Michael T1 - Enhancing Information Systems with Event-Handling - A Non-Invasive Approach T1 - Erweiterung von Informationssystemen um Event-Handling - Ein Nicht-Invasiver Ansatz N2 - Due to the immense advance of widely accessible information systems in industrial applications, science, education and every day use, it becomes more and more difficult for users of those information systems to keep track with new and updated information. An approach to cope with this problem is to go beyond traditional search facilities and instead use the users' profiles to monitor data changes and to actively inform them about these updates - an aspect that has to be explicitly developed and integrated into a variety of information systems. This is traditionally done in an individual way, depending on the application and its platform. In this dissertation, we present a novel approach to model the semantic interrelations that specify which users to inform about which updates, based on the underlying model of the respective information system. For the first time, a meta-model that allows information system designers to tag an arbitrary data model and thus specify the event-handling semantics is presented. A formal specification of how to interpret meta-models to determine the receivers of the events completes the presented concept. For the practical realization of this new concept, model driven architecture (MDA) shows to be an ideal technical means. Using our newly developed UML profile based on data-modelling standards, an implementation of the event-handling specification can automatically be generated for a variety of different target platforms, like e.g. relational databases, using triggers. This meta-approach makes the proposed solution ideal with respect to maintainability and genericity. Our solution significantly reduces the overall development efforts for an event-handling facility. In addition, the enhanced model of the information system can be used to generate an implementation that also fulfils non-functional requirements like high performance and extensibility. The overall framework, consisting of the domain specific language (i.e. the meta-model), formal and technical transformations of how to interpret the enhanced information system model and a cost-based optimizing strategy, constitutes an integrated approach, offering several advantages over traditional implementation techniques: our framework can be applied to new information systems as well as to legacy applications without having to modify existing systems; it offers an extensible, easy-to-use, generic and thus re-usable solution and it can be tailored to and optimized for many use cases, as the practical evaluation presented in this dissertation verifies. N2 - Bedingt durch die immer stärkere Durchdringung rechnergestützter Informationssysteme in Industrie, Forschung, Ausbildung und anderen Bereichen des täglichen Lebens wird es für Anwender immer schwieriger, für sie relevante Änderungen an den dort gespeicherten Datenbeständen nachzuverfolgen. Dem wird häufig dadurch begegnet, dass über die Fähigkeiten traditioneller Suchmöglichkeiten hinaus gegangen wird und Profile der Anwender verwendet werden, um sie aktiv über relevante Änderungen zu informieren. Dieser Aspekt muss für unterschiedlichste Informationssysteme explizit entwickelt und integriert werden, zudem meist abhängig von der fachlichen Domäne der Anwendung und deren Plattform. In dieser Dissertation präsentieren wir einen neuartigen Ansatz, mit dessen Hilfe die semantischen Vorgaben, welche Anwender über welche Änderungen informiert werden sollen, ausgehend vom zugrunde liegenden Datenmodell der Anwendung des jeweiligen Systems modelliert werden können. Erstmalig wird ein Meta-Modell vorgestellt, das Entwicklern und Architekten ermöglicht, ein beliebiges Modell eines Informationssystems mit zusätzlichen Informationen auszuzeichnen und damit die Semantik der Event-Handling-Komponente vorzugeben. Zudem wird ein formales Konzept präsentiert, das spezifiziert wie diese Auszeichnungen für die Bestimmung der Informationsempfänger zu interpretieren sind. Im Hinblick auf die Realisierung dieses Konzepts erweist sich Model Driven Architecture (MDA) als ideales technisches Mittel. Mit Hilfe eines eigens entwickelten UML Profils, das sich auf existierende Standards zur Datenmodellierung stützt, kann automatisch eine Implementierung der Event-Handling-Komponenten für eine Vielzahl unterschiedlichster Zielplattformen generiert werden. Als Beispiel wäre die Verwendung relationaler Datenbanken zusammen mit Datenbanktriggern zu nennen. Dieser Ansatz stellt eine ideale Lösung im Hinblick auf Wartbarkeit und Allgemeingültigkeit dar, wodurch auch der Entwicklungsaufwand minimiert wird. Zudem bietet unser Ansatz auch die Möglichkeit, bei der Implementierung dieser Komponente auch nicht-funktionale Anforderungen - wie beispielsweise möglichst optimale Performanz und Erweiterbarkeit - zu erfüllen. Das hier präsentierte Framework, bestehend aus der domänen-spezifischen Sprache (in Form des Meta-Modells), den formalen und technischen Transformationsvorschriften für die Interpretation der Spezifikation sowie einer kostenbasierten Optimierungsstrategie, stellt einen integrierten Ansatz dar, der im Vergleich zu traditionellen Ansätzen einige Vorteile bietet: so kann dieser Ansatz ohne Modifikation existierender Systeme verwendet werden, stellt eine erweiterbare, einfach benutzbare, und zugleich wiederverwendbare Lösung dar und kann für beliebige Anwendungsfälle maßgeschneidert und optimiert werden, wie die Evaluation unserer Lösung anhand echter Szenarien in dieser Dissertation zeigt. KW - Notifikation KW - Abonnement KW - Modellierung KW - Generierung KW - Relationale Datenbank KW - MDA KW - Trigger KW - Aktive Datenbanken KW - Metamodellierung KW - Publish/Subscribe KW - Publish/Subscribe KW - Notification KW - Active Database Systems KW - MDA KW - Trigger Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus-22485 ER - TY - THES A1 - Berl, Andreas T1 - Energy Efficiency in Office Computing Environments T1 - Energieeffizienz in Büroumgebungen N2 - The increasing cost of energy and the worldwide desire to reduce CO2 emissions has raised concern about the energy efficiency of information and communication technology. Whilst research has focused on data centres recently, this thesis identifies office computing environments as significant consumers of energy. Office computing environments offer great potential for energy savings: On one hand, such environments consist of a large number of hosts. On the other hand, these hosts often remain turned on 24~hours per day while being underutilised or even idle. This thesis analyzes the energy consumption within office computing environments and suggests an energy-efficient virtualized office environment. The office environment is virtualized to achieve flexible virtualized office resources that enable an energy-based resource management. This resource management stops idle services and idle hosts from consuming resources within the office and consolidates utilised office services on office hosts. This increases the utilisation of some hosts while other hosts are turned off to save energy. The suggested architecture is based on a decentralized approach that can be applied to all kinds of office computing environments, even if no centralized data centre infrastructure is available. The thesis develops the architecture of the virtualized office environment together with an energy consumption model that is able to estimate the energy consumption of hosts and network within office environments. The model enables the energy-related comparison of ordinary and virtualized office environments, considering the energy-efficient management of services. Furthermore, this thesis evaluates energy efficiency and overhead of the suggested approach. First, it theoretically proves the energy efficiency of the virtualized office environment with respect to the energy consumption model. Second, it uses Markov processes to evaluate the impact of user behaviour on the suggested architecture. Finally, the thesis develops a discrete-event simulation that enables the simulation and evaluation of office computing environments with respect to varying virtualization approaches, resource management parameters, user behaviour, and office equipment. The evaluation shows that the virtualized office environment saves more than half of the energy consumption within office computing environments, depending on user behaviour and office equipment. N2 - Die steigenden Kosten von Energie und die weltweiten Bemühungen CO2-Emmissionen zu reduzieren, führt aktuell zu einer intensiven Untersuchung der Energieeffizienz von Informations- und Kommunikationstechnologien. Während ein großer Teil der aktuellen Forschung sich auf Rechenzentren fokussiert, betrachtet diese Arbeit Büroumgebungen mit ihren Rechnern und dem verbindenden Netzwerk. Eine energieeffiziente Architektur wird vorgeschlagen, die auf die Virtualisierung und Konsolidierung von Diensten setzt, ohne auf zentralisierte Rechenzentrumshardware oder Thin Clients angewiesen zu sein. KW - Energieeffizienz KW - Virtualisierung KW - Konsolidierung KW - Büro KW - Energy efficiency KW - virtualization KW - consolidation KW - office computing environments Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:739-opus-22516 ER -