CriterEUS – Ein multikriterielles Entscheidungsunterstütztungssystem unter Exel

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Magnetic clamping structures for the consolidation of composite laminates

Vacuum bags in conjunction with autoclaves are currently employed to generate the consolidation pressures and temperatures required to manufacture aerospace level composites. As the scale of continuous fiber composite structures increases autoclaving becomes prohibitively expensive or impossible. The objective of this work is to develop flexible magnetic clamping structures to increase the consolidation pressure in conventional vacuum bagging of composite laminates, thereby obviating the need for an autoclave. A ferromagnetic rubber, which consists of rubber filled with iron, is being developed as a conformable and reusable vacuum bag that provides increased consolidation through attractive forces produced by electromagnets. Experiments and finite element modeling indicate that consolidation pressure in the range of 100 kPa can be generated by such a device with realistic power requirements. The effects of the magnetic clamping device process parameters on the consolidation pressure magnitude are modeled and characterized. In addition, a method for the efficient design of the magnetic clamping device is developed.MSCommittee Chair: Jonathan Colton; Committee Member: John Schultz; Committee Member: Steven Danylu

Universität als Stadtbaustein. Potenziale einer wissensbasierten Stadtentwicklung in den neuen Bundesländern

Die Autorin blickt als Stadtplanerin auf die \u27Universitäten als Stadtbaustein\u27: Sie geht von der These aus, dass eine bessere und gezieltere Ausnutzung der universitäts- und wissensbezogenen Potenziale der Schlüssel zur erfolgreichen Behauptung der ostdeutschen Universitätsstädte im Wettbewerb der Regionen sei. Anhand dreier Fallstädte (Potsdam, Dresden und Weimar) wird nach den wichtigsten Rahmenbedingungen gefahndet, die Potenziale einer wissensbasierten Stadtentwicklung freisetzen könnten. Die drei untersuchten Städte könnten, so das Fazit, bislang noch nicht als Prototypen der Stadt in der Wissensgesellschaft gelten - gleichwohl Potenziale dafür vorhanden seien. (HoF/Text übernommen

A Compositional Approach to Embedded System Design

An important observable trend in embedded system design is the growing system complexity. Besides the sheer increase of functionality, the growing complexity has another dimension which is the resulting heterogeneity with respect to the different functions and components of an embedded system. This means that functions from different application domains are tightly coupled in a single embedded system. It is established industry practice that specialized specification languages and design environments are used in each application domain. The resulting heterogeneity of the specification is increased even further by reused components (legacy code, IP). Since there is little hope that a single suitable language will replace this heterogeneous set of languages, multi-language design is becoming increasingly important for complex embedded systems. The key problems in the context of multi-language design are the safe integration of the differently specified subsystems and the optimized implementation of the whole system. Both require the reliable validation of the system function as well as of the non-functional system properties. Current cosimulation-based approaches are well suited for functional validation and debugging. However, these approaches are less powerful for the validation of non-functional system properties. In this dissertation, a novel compositional approach to embedded system design is presented which augments existing cosimulation-based design flows with formal analysis capabilities regarding non-functional system properties such as timing or power consumption. Starting from a truly multi-language specification, the system is transformed into an abstract internal design representation which serves as basis for system-wide analysis and optimization.Ein wesentlicher Trend im Entwurf eingebetteter Systeme ist die steigende Komplexität der zu entwerfenden Systeme. Neben der zunehmenden Funktionalität hat die steigende Komplexität eine weitere Dimension: die resultierende Heterogenität bezüglich der verschiedenen Funktionen und Komponenten eines eingebetteten Systems. Dies bedeutet, daß Funktionen aus verschiedenen Anwendungsbereichen in einem einzelnen System eng miteinander kooperieren. Es ist in der industriellen Praxis etabliert, daß in jedem Anwendungsbereich spezialisierte Spezifikationssprachen zum Einsatz kommen. Da wenig Hoffnung besteht, daß eine einzige geeignete Sprache diesen heterogenen Mix von Sprachen ersetzen wird, gewinnt der mehrsprachige Entwurf für komplexe eingebettete Systeme an Bedeutung. Die Hauptprobleme im Bereich des mehrsprachigen Entwurfs sind die sichere Integration der verschieden spezifizierten Teilsysteme und die optimierte Implementierung des gesamten Systems. Beide Probleme verlangen eine zuverlässige Validierung der Systemfunktion sowie der nichtfunktionalen Systemeigenschaften. Heutige cosimulationsbasierte Ansätze aus Forschung und Industrie sind gut geeignet für die funktionale Validierung und Fehlersuche, haben aber Schwächen bei der Validierung nichtfunktionaler Systemeigenschaften. In der vorliegenden Arbeit wird ein neuartiger kompositionaler Ansatz für den Entwurf eingebetteter Systeme vorgestellt, der existierende cosimulationsbasierte Entwurfsflüsse um Fähigkeiten zur Analyse nichtfunktionaler Systemeigenschaften ergänzt. Ausgehend von einer mehrsprachigen Spezifikation, wird das System in eine abstrakte homogene interne Darstellung transformiert, die als Grundlage für die systemweite Analyse und Optimierung dient

Evaluation of the impact of noise metrics on tiltrotor aircraft design

A subjective noise evaluation was conducted in which the test participants evaluated the annoyance of simulated sounds representative of future civil tiltrotor aircraft. The subjective responses were correlated with the noise metrics of A-weighted sound pressure level, overall sound pressure level, and perceived level. The results indicated that correlation between subjective response and A-weighted sound pressure level is considerably enhanced by combining it in a multiple regression with overall sound pressure level. As a single metric, perceived level correlated better than A-weighted sound pressure level due to greater emphasis on low frequency noise components. This latter finding was especially true for indoor noise where the mid and high frequency noise components are attenuated by typical building structure. Using the results of the subjective noise evaluation, the impact on tiltrotor aircraft design was also evaluated. While A-weighted sound pressure level can be reduced by reduction in tip speed, an increase in number of rotor blades is required to achieve significant reduction of low frequency noise as measured by overall sound pressure level. Additional research, however, is required to achieve comparable reductions in impulsive noise due to blade-vortex interaction, and also to achieve reduction in broad band noise

Pyrimidinone: Versatile Trojan horse in DNA photodamage?

(6-4) Photolesions between adjacent pyrimidine DNA bases are prone to secondary photochemistry. It has been shown that singlet excited (6-4) moieties form Dewar valence isomers as well as triplet excitations. We here report on the triplet state of a minimal model for the (6-4) photolesion, 1-methyl-2(1H)-pyrimidinone. Emphasis is laid on its ability to abstract hydrogen atoms from alcohols and carbohydrates. Steady-state and time-resolved experiments consistently yield bimolecular rate constants of ∼104 M−1 s−1 for the hydrogen abstraction. The process also occurs intramolecularly as experiments on zebularine (1-(β-D-ribofuranosyl)-2(1H)-pyrimidinone) show

Control-System Stability Under Consecutive Deadline Misses Constraints

This paper deals with the real-time implementation of feedback controllers. In particular, it provides an analysis of the stability property of closed-loop systems that include a controller that can sporadically miss deadlines. In this context, the weakly hard m-K computational model has been widely adopted and researchers used it to design and verify controllers that are robust to deadline misses. Rather than using the m-K model, we focus on another weakly-hard model, the number of consecutive deadline misses, showing a neat mathematical connection between real-time systems and control theory. We formalise this connection using the joint spectral radius and we discuss how to prove stability guarantees on the combination of a controller (that is unaware of deadline misses) and its system-level implementation. We apply the proposed verification procedure to a synthetic example and to an industrial case study