Eine dienstorientierte Methodik zur Koppelung von Netz-QoS-Architekturen

In recent years, distributed IT applications were developed which pose explicit requirements on the quality of end-to-end connections between the participating parties. Examples include voice-over-IP, video conferencing etc. Hence, those applications' functionality is significantly influenced by the underlying network infrastructures on which applications build upon. Services offered by networks must therefore meet certain criteria of quality - they have to provide and enforce quality-of-service (QoS). For this reason, different architectures have been and still are being developed to realize QoS on the network level. While such architectures have proven to be functional in principle for homogeneous networks of single providers, the situation is completely different when it comes to interconnecting autonomous or/and heterogeneous networks. Today, no QoS-enabled network services are offered which span multiple provider domains. But this is expected and necessary for the future, last but not least because of the pressure imposed by the application level. As there is no universal QoS architecture on the horizon to become accepted globally, ways have to be found to handle heterogeneity in a network of networks. --- When reviewing existing work in the field, it becomes evident that most approaches are limited to specific architectures or certain services. What is still missing is a universal internetworking architecture which could be applied in any situation and to any QoS architecture. The existence of such a generic architecture seems to be uncertain regarding the complexity of the task and the broad spectrum of QoS architectures which have to covered. --- This thesis strictly follows a service-oriented approach which can be summarized as "a generic way for gaining a specific solution". The approach consists of two major steps. The starting point of the first step are the QoS network services which are to be coupled as well as the QoS architectures these services are built upon. Initially, a normalized representation of the architectures is gained by modeling. In doing so, static and dynamic aspects of QoS architectures are considered. Afterwards, the modeling of QoS network services itself takes place and is based on the models for architectures. The whole modeling process creates a normalized starting point for the second major step. It consists of a generic methodology for gaining specific solutions to solve the coupling problem for individual cases. In this step the necessary architectural building blocks and the required workflows for the coupling are identified. The modeling as well as the methodology are strictly service-oriented, especially in considering the whole service life cycle for both parts. --- The generic model and the methodology are illustrated by a series of examples which are derived from real world scenarios. The thesis' results are supported by an analysis of different business use cases, e.g. bid invitation, estimation of effort etc.Seit einiger Zeit werden verteilte IT-Anwendungen entwickelt, die dezidierte Anforderungen an die Qualität der Ende-zu-Ende-Verbindung zwischen ihren Teilnehmern stellen (z.B. Voice-over-IP, Videokonferenzsysteme etc.). Damit wird die Funktionsfähigkeit solcher Applikationen maßgeblich durch die Beschaffenheit von Netz-Infrastrukturen bestimmt, auf denen sie aufbauen. Die von einem Netz bereitgestellten Dienste müssen also gewissen Qualitätsansprüchen genügen, sie müssen eine Dienstgüte bzw. Quality-of-Service (QoS) anbieten und durchsetzen. Hierzu wurden und werden unterschiedlichste Architekturen entworfen, die QoS auf Ebene eines Netzes realisieren. Während diese Architekturen in homogenen Netzen einzelner Betreiber ihre Funktionsfähigkeit prinzipiell gezeigt haben, stellt sich auf Ebene der Netzverbünde ein vollständig anderes Bild dar. Betreiberübergreifend werden heute keine Netzdienste mit QoS angeboten, nicht zuletzt aufgrund des Drucks von Seiten der Anwendungen wird dies aber für die Zukunft erwartet. Da weiterhin nicht abzusehen ist, dass sich global eine gemeinsame Netz-QoS-Architektur durchsetzen wird, müssen Möglichkeiten gefunden werden, wie die Heterogenität im Netzverbund gehandhabt werden kann. --- Betrachtet man bestehende Arbeiten, so fällt auf, dass diese größtenteils auf die Betrachtung spezifischer Architekturen oder bestimmter Dienste begrenzt sind. Eine universelle Koppelungsarchitektur im Sinne einer für jeden Fall unmittelbar anwendbaren Lösung wurde bisher nicht entwickelt. Die Komplexität der Fragestellung und der Breite des Spektrums denkbarer Netz-QoS-Architekturen lassen eine Existenz einer solchen allgemeinen Koppelungsarchitektur auch fraglich erscheinen. --- Die Dissertation verfolgt einen strikt dienstorientierten Ansatz, der sich in einem Satz als "Generischer Weg zur Gewinnung einer spezifischen Lösung" zusammenfassen lässt. Dabei werden im Wesentlichen zwei Hauptschritte durchgeführt. Ausgangspunkt des ersten Schritts sind die zu koppelnden Netz-QoS-Dienste. Sie werden durch Modellierung in eine normalisierte Darstellung überführt. Dabei werden unter Betrachtung statischer und dynamischer Aspekte zuerst die den Diensten zugrunde liegenden Netz-QoS-Architekturen modelliert. Hierauf basierend werden Modelle für Netz-QoS-Dienste erstellt. Durch die Normalisierung ist die Grundlage gelegt, um im zweiten Schritt mittels der dann entworfenen generischen Methodik die fallspezifische Lösung gewinnen zu können. Dabei werden, neben der Identifizierung der zur Koppelung notwendigen architekturellen Bausteine, auch die für die Koppelung benötigten Arbeitsabläufe bestimmt. Sowohl Modellierung als auch die Methodik sind an den Gesichtspunkten der Dienstorientierung ausgerichtet, speziell wird in beiden Teilen der gesamte Lebenszyklus eines Dienstes betrachtet. --- Illustriert werden Modellierung und Methodik an verschiedenen Beispielen, die ihren Ursprung in realen Szenarios haben. Die Betrachtung unterschiedlicher geschäftlicher Anwendungsfälle (wie z.B. Ausschreibung, Aufwandsabschätzung etc.) rundet die Arbeit ab

Human-Machine Interaction in Care-Education

The research project ERTRAG, funded by the German Federal Ministry of Education and Research, aims to develop a virtual ergonomics trainer for nursing as well as elderly care education. The trainer supports apprentices conducting the care related motions in an ergonomically correct fashion, thereby helping to prevent work-related health problems such as dorsal pain. The user interface of the ERTRAG system for instruction and feedback adjusts to the individual preferences and needs, as well as to the current cognitive state of the user. This adaptive, highly customizable human-machine interaction fosters effective and long-lasting learning.publishe

Towards generic service management concepts - a service model based approach

Service management has been a hot topic in the research community for the last couple of years. However, due to the complexity of this research area, no commonly accepted definition of the terms service, service management, and the associated management tasks has evolved yet. This paper contributes to the ongoing process of defining these terms by proposing a top–down oriented and systematic methodology that is used to analyze and identify the necessary actors and the corresponding inter – and intra–organizational relationships. Then, a generic service model is introduced that defines commonly needed service– related terms, concepts and structuring rules in a general and unambiguous way. Since most of the work that is being presented here is still in flux, the service model is finally used to identify and structure open research questions

Metathesis in water conducted by tailor-made encapsulated Grubbs' catalyst

Pauly J, Gröger H, Patel AV. Metathesis in water conducted by tailor-made encapsulated Grubbs' catalyst. Green Chemistry. 2018;20(22):5179-5187.Metathesis in water represents a current challenge in green chemistry, since hydrophobic catalysts are non-soluble in this medium. Although this issue has been addressed by modification of the hydrophobic ligand structure, alternative methods for conducting metathesis in water are of interest, such as catalyst encapsulation. In this contribution we report successful encapsulation of the Grubbs' second-generation catalyst in alginate hydrogels, representing a renewable resource, to perform ring-closing metathesis (RCM) in water. We initially investigated the influence of different solvents on the reaction rate and confirmed that water is a preferred solvent. A comparison of non-encapsulated and encapsulated catalyst in calcium alginate revealed that the reaction rate for non-encapsulated catalyst was notably higher, which can be explained by on water conditions in this case. Inside the beads the encapsulated catalyst remained heterogeneous, thus allowing to switch the catalysis mode between in/on water through encapsulation. To overcome diffusion limitation and enhance reaction rate, we prepared a tailor-made bead material by introducing hydrophobic octyl-grafted alginate amide. Using such a hydrogel, diffusion limitation was positively influenced by hydrophobisation of the matrix, resulting in up to quadrupled reaction rates compared to calcium alginate as a standard encapsulation material. In terms of recycling, this encapsulated catalyst revealed promising performance, retaining 80% of its activity after ten runs. This is the first reported application of hydrophobised alginate derivatives in catalysed organic synthesis, achieving excellent encapsulation efficiency, no measurable leaching and yields of up to 87%