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Vortrag am 04.12.2009, 10:00 Uhr
by Informatik-Kolloquium 05 Nov '09

05 Nov '09

Die Dozenten der Informatik-Institute der Technischen Universität Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem Vortrag ein: Prof. Dr.-Ing. Bodo Rosenhahn, Leibniz Universität Hannover, Institut für Informationsverarbeitung: New Trends in Markerless Motion Capture Beginn: 04.12.2009, 10:00 Uhr Ort: TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23, Galeriegeschoss, Raum G04 Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2009-12-04-rosenhahn.html Kontakt: Prof. Dr.-Ing. F. M. Wahl Der Vortrag behandelt das Thema der Markerlosen Bewegungserfassung (Motion Capture) von artikulierten Objekten aus Videodaten. Es wird ein silhouettenbasiertes Markerloses Motion Capture System präsentiert, welches seit vielen Jahren sukzessive erweitert wird um Personen in Aussenbereichen und komplexen Situationen erfolgreich verfolgen zu können. Hierzu fliesst Modelwissen ein um Segmentierung, Registrierung oder Poseschätzung effizient lösen zu können. Desweiteren werden effiziente Retrieval-methoden, statistische Lernverfahren und ein morphable Body-Shape Modell vorgestellt um Kleidung, Redundanzen oder Uneindeutigkeiten effizient auflösen zu können.

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Erinnerung: Vortrag am 23.10.2009, 10:00 Uhr
by Informatik-Kolloquium 22 Oct '09

22 Oct '09

Die Dozenten der Informatik-Institute der Technischen Universität Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem Vortrag ein: Srboljub M. Mijailovich, Ph.D., Harvard School of Public Health: Quantitative Bioengineering Analysis of Muscle Mechanics and Metabolism Beginn: 23.10.2009, 10:00 Uhr Ort: TU Braunschweig, Gauß-IT-Zentrum, Hans-Sommer-Str. 65, Seminarraum 012 Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2009-10-23-mijailovich.html Kontakt: Prof. Hermann G. Matthies, PhD Using the methods of engineering analysis, we have developed a computational platform that incorporates current knowledge of molecular structure, biochemical energetics, and actomyosin binding kinetics to describe muscle contraction. Developed comprehensive model can be used to (1) generate new mechanistic hypotheses concerning the functions of the contractile proteins myosin and actin and (2) quantitatively evaluate the roles of accessory and regulatory proteins in contraction. This computational model is a powerful analytical and predictive tool in studies of muscle physiology in health and disease. Presently, no models of contraction account for complications due to both (1) extensibility of the actin and myosin filaments and (2) Ca2+ regulation of contraction. Filament extensibility results in non-uniform load transfer along the thick and thin filaments, which introduces variability in the stress and strain of the myosin heads during their interactions with actin. These effects must be taken into account to understand how cross-bridge forces affect chemical transitions in the actomyosin ATPase cycle and vice versa. Further, quantitative understanding of Ca2+ regulation will allow (1) more accurate predictions of the macroscopic mechanical and energetic consequences of specific regulatory events and (2) more accurate explanations of macroscopic events in terms of underlying molecular processes. These problems are addressed via a multidisciplinary approach that spans engineering science, computational science, and biophysics and rests entirely upon first principles. The developed model integrates a critical missing element – filament extensibility – with recent advances in understanding the (1) biochemical states of myosin; (2) transitional rate constants in the actomyosin ATP hydrolysis cycle; (3) function of myosin molecular motors in the thick and thin filament lattice (sarcomere); and (4) Ca2+ regulation of myosin binding. The model combines either probabilistic or stochastic actomyosin binding kinetics with finite element analysis including spatially discrete sarcomere lattice consistent with the periodicities of the thick and thin filaments. The developed computational model invokes unifying principles that apply to the actomyosin cycle regardless of muscle type and it has sufficient flexibility to account for contraction kinetics and regulation of contraction in different muscle types. Quantitative modeling of contraction is ultimately essential for understanding the molecular basis for a wide range of syndromes and diseases, such as airway narrowing in asthma and weakness of both heart and skeletal muscles in heart failure.

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Erinnerung: Vortrag am 22.10.2009, 10:00 Uhr
by Informatik-Kolloquium 21 Oct '09

21 Oct '09

Die Dozenten der Informatik-Institute der Technischen Universität Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem Vortrag ein: Srboljub M. Mijailovich, Ph.D., Harvard School of Public Health: Molecular Origins of Airway Narrowing: Multiscle Model Predictions of Hyperresponsiveness in Asthmatics Beginn: 22.10.2009, 10:00 Uhr Ort: TU Braunschweig, Gauß-IT-Zentrum, Hans-Sommer-Str. 65, Seminarraum 012 Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2009-10-22-mijailovich.html Kontakt: Prof. Hermann G. Matthies, PhD We have developed a theoretical multiscale model to quantify how alterations in the cross-bridge kinetics of airway smooth muscle (ASM) and in the airway wall remodeling affect the symptoms of asthma and chronic obstructive pulmonary disease (COPD). By taking into account the coupling between ASM contraction and the dynamics of breathing, the new model is able to predict the hyperreactivity of the asthmatic airways and their hypersensitivity to increasing doses of contractile agents. The latter could not be reproduced by previous models that considered static equilibrium between the isometric ASM force and the mean transpulmonary pressure. In the presented model the airway caliber – proportional to the ASM length – is dynamically determined from the instantaneous balance between airway wall reaction force (AWRF) and the ASM contractile force. The AWRF is derived from transmural pressure across the airway wall and the forces of parenchymal tethering: it is computed from the elasticity and geometry of the airway wall, the tethering of the airway to the lung parenchyma, and the state of lung inflation. The resulting force is equivalent to an instantaneous load acting on the ASM in situ. This force depends on the transpulmonary pressure variation and the pressure drop along the airway tree during breathing. The ASM contractile force and length are determined using Mijailovich’s molecular model of smooth muscle contraction and regulation, based on the perturbed equilibria of myosin binding. The instantaneous airway luminal area and resistance are obtained from the ASM length for each airway generation in Weibel’s bronchial tree. The pressure drop along the tree is computed from the resistance and the instantaneous flow rate. The calculations include the effect of deep inspirations (DI) superimposed over quiet tidal breathing for normal, COPD, and asthmatic airways. Our results show that at low doses of histamine, ASM reaches dynamical equilibrium at long lengths, and the airways are completely open and compliant. However, at histamine doses above a “critical” value, the ASM drastically shortens, and the airways are severely constricted and stiff. In COPD and asthmatic airways the critical dose is significantly lower than in normal airways; above this dose the degree of ASM shortening, and therefore airway constriction, are both significantly greater than in normal airways. In this case, DI may not be sufficient to open the asthmatic airways. The agreement between the model predictions and clinical observations suggests that both the hyperreactivity and hypersensitivity observed in asthmatic and COPD airways can be explained by a single mechanism – perturbed equilibria of myosin binding.

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Vortrag am 22.10.2009, 10:00 Uhr
by Informatik-Kolloquium 08 Oct '09

08 Oct '09

Die Dozenten der Informatik-Institute der Technischen Universität Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem Vortrag ein: Srboljub M. Mijailovich, Ph.D., Harvard School of Public Health: Molecular Origins of Airway Narrowing: Multiscle Model Predictions of Hyperresponsiveness in Asthmatics Beginn: 22.10.2009, 10:00 Uhr Ort: TU Braunschweig, Gauß-IT-Zentrum, Hans-Sommer-Str. 65, Seminarraum 012 Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2009-10-22-mijailovich.html Kontakt: Prof. Hermann G. Matthies, PhD We have developed a theoretical multiscale model to quantify how alterations in the cross-bridge kinetics of airway smooth muscle (ASM) and in the airway wall remodeling affect the symptoms of asthma and chronic obstructive pulmonary disease (COPD). By taking into account the coupling between ASM contraction and the dynamics of breathing, the new model is able to predict the hyperreactivity of the asthmatic airways and their hypersensitivity to increasing doses of contractile agents. The latter could not be reproduced by previous models that considered static equilibrium between the isometric ASM force and the mean transpulmonary pressure. In the presented model the airway caliber – proportional to the ASM length – is dynamically determined from the instantaneous balance between airway wall reaction force (AWRF) and the ASM contractile force. The AWRF is derived from transmural pressure across the airway wall and the forces of parenchymal tethering: it is computed from the elasticity and geometry of the airway wall, the tethering of the airway to the lung parenchyma, and the state of lung inflation. The resulting force is equivalent to an instantaneous load acting on the ASM in situ. This force depends on the transpulmonary pressure variation and the pressure drop along the airway tree during breathing. The ASM contractile force and length are determined using Mijailovich’s molecular model of smooth muscle contraction and regulation, based on the perturbed equilibria of myosin binding. The instantaneous airway luminal area and resistance are obtained from the ASM length for each airway generation in Weibel’s bronchial tree. The pressure drop along the tree is computed from the resistance and the instantaneous flow rate. The calculations include the effect of deep inspirations (DI) superimposed over quiet tidal breathing for normal, COPD, and asthmatic airways. Our results show that at low doses of histamine, ASM reaches dynamical equilibrium at long lengths, and the airways are completely open and compliant. However, at histamine doses above a “critical” value, the ASM drastically shortens, and the airways are severely constricted and stiff. In COPD and asthmatic airways the critical dose is significantly lower than in normal airways; above this dose the degree of ASM shortening, and therefore airway constriction, are both significantly greater than in normal airways. In this case, DI may not be sufficient to open the asthmatic airways. The agreement between the model predictions and clinical observations suggests that both the hyperreactivity and hypersensitivity observed in asthmatic and COPD airways can be explained by a single mechanism – perturbed equilibria of myosin binding.

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Vortrag am 23.10.2009, 10:00 Uhr
by Informatik-Kolloquium 08 Oct '09

08 Oct '09

Die Dozenten der Informatik-Institute der Technischen Universität Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem Vortrag ein: Srboljub M. Mijailovich, Ph.D., Harvard School of Public Health: Quantitative Bioengineering Analysis of Muscle Mechanics and Metabolism Beginn: 23.10.2009, 10:00 Uhr Ort: TU Braunschweig, Gauß-IT-Zentrum, Hans-Sommer-Str. 65, Seminarraum 012 Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2009-10-23-mijailovich.html Kontakt: Prof. Hermann G. Matthies, PhD Using the methods of engineering analysis, we have developed a computational platform that incorporates current knowledge of molecular structure, biochemical energetics, and actomyosin binding kinetics to describe muscle contraction. Developed comprehensive model can be used to (1) generate new mechanistic hypotheses concerning the functions of the contractile proteins myosin and actin and (2) quantitatively evaluate the roles of accessory and regulatory proteins in contraction. This computational model is a powerful analytical and predictive tool in studies of muscle physiology in health and disease. Presently, no models of contraction account for complications due to both (1) extensibility of the actin and myosin filaments and (2) Ca2+ regulation of contraction. Filament extensibility results in non-uniform load transfer along the thick and thin filaments, which introduces variability in the stress and strain of the myosin heads during their interactions with actin. These effects must be taken into account to understand how cross-bridge forces affect chemical transitions in the actomyosin ATPase cycle and vice versa. Further, quantitative understanding of Ca2+ regulation will allow (1) more accurate predictions of the macroscopic mechanical and energetic consequences of specific regulatory events and (2) more accurate explanations of macroscopic events in terms of underlying molecular processes. These problems are addressed via a multidisciplinary approach that spans engineering science, computational science, and biophysics and rests entirely upon first principles. The developed model integrates a critical missing element – filament extensibility – with recent advances in understanding the (1) biochemical states of myosin; (2) transitional rate constants in the actomyosin ATP hydrolysis cycle; (3) function of myosin molecular motors in the thick and thin filament lattice (sarcomere); and (4) Ca2+ regulation of myosin binding. The model combines either probabilistic or stochastic actomyosin binding kinetics with finite element analysis including spatially discrete sarcomere lattice consistent with the periodicities of the thick and thin filaments. The developed computational model invokes unifying principles that apply to the actomyosin cycle regardless of muscle type and it has sufficient flexibility to account for contraction kinetics and regulation of contraction in different muscle types. Quantitative modeling of contraction is ultimately essential for understanding the molecular basis for a wide range of syndromes and diseases, such as airway narrowing in asthma and weakness of both heart and skeletal muscles in heart failure.

1 0

Erinnerung: Vortrag am 16.09.2009, 10:00 Uhr
by Informatik-Kolloquium 15 Sep '09

15 Sep '09

Die Dozenten der Informatik-Institute der Technischen Universität Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem Vortrag ein: Zornitza Racheva, Universität von Twente, Niederlande: Investigating the requirements prioritization in agile projects Beginn: 16.09.2009, 10:00 Uhr Ort: TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23, 3. OG, Raum 349 Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2009-09-16-racheva.html Kontakt: Dr. Andrea Herrmann Continuous customer-centric requirements prioritization is essential in successfully performing agile software development. Agile requirements engineering is unique in two ways: (1) (re)prioritization happens at inter-iteration time, and (2) the client plays a key role for making prioritization decisions. In this presentation I'll outline our investigation on the topic of agile prioritization methods, that yield a conceptual model for understanding the inter-iteration prioritization process. One of our findings is that the concept of business value plays a key role in the process, and we performed further study, dedicated to the definition and understanding of this concept. I'll comment on the results and implications of our study for research and practice and will discuss our goals and future work. The topic will be positioned in the context of the QuadRead (Quality Driven Requirements Engineering and Architecture Design) project.

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Vortrag am 16.09.2009, 10:00 Uhr
by Informatik-Kolloquium 04 Sep '09

04 Sep '09

Die Dozenten der Informatik-Institute der Technischen Universität Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem Vortrag ein: Zornitza Racheva, Universität von Twente, Niederlande: Investigating the requirements prioritization in agile projects Beginn: 16.09.2009, 10:00 Uhr Ort: TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23, 3. OG, Raum 349 Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2009-09-16-racheva.html Kontakt: Dr. Andrea Herrmann Continuous customer-centric requirements prioritization is essential in successfully performing agile software development. Agile requirements engineering is unique in two ways: (1) (re)prioritization happens at inter-iteration time, and (2) the client plays a key role for making prioritization decisions. In this presentation I'll outline our investigation on the topic of agile prioritization methods, that yield a conceptual model for understanding the inter-iteration prioritization process. One of our findings is that the concept of business value plays a key role in the process, and we performed further study, dedicated to the definition and understanding of this concept. I'll comment on the results and implications of our study for research and practice and will discuss our goals and future work. The topic will be positioned in the context of the QuadRead (Quality Driven Requirements Engineering and Architecture Design) project.

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Vortrag am 10.07.2009, 14:00 Uhr
by Christa Schweda 02 Jul '09

02 Jul '09

Die Dozenten der Informatik-Institute der Technischen Universität Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem Vortrag ein: Herr Dr. Bastian Goldlücke, Department of Computer Science, University of Bonn, Beginn: 10.07.2009, 14:00 Uhr Ort: TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23, 2. OG, Raum 251 Kontakt: Prof. Dr. Wolf-Tilo Balke "A Superresolution Framework for High-Accuracy Multiview Reconstruction" Focus of this talk are the current state-of-the-art methods for 3D reconstruction from multiple calibrated views which were developed in our group. Based on a convex formulation for the 3D reconstruction problem, an initial 3D model is obtained. The geometry is further refined in a combined variational approach to jointly estimate a displacement map and a super-resolved texture for the model. The super-resolution approach to texture reconstruction allows to obtain fine details in the texture map which surpass individual input image resolution Some of the interesting mathematical background can be applied quite generally and is briefly discussed. This includes convex relaxation techniques for global optimization of certain total variation based energy functionals, as well as an algorithm for solving partial differential equations on surfaces.

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Erinnerung: Vortrag am 25.06.2009, 14:00 Uhr
by Informatik-Kolloquium 24 Jun '09

24 Jun '09

Die Dozenten der Informatik-Institute der Technischen Universität Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem Vortrag ein: Prof. Ingo Schmitt, Datenbank- und Informationssysteme, TU Cottbus: Quantenlogikbasierte Suche in Datenbanken Beginn: 25.06.2009, 14:00 Uhr Ort: TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23, 2. OG, Raum 251 Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2009-06-25-schmitt.html Kontakt: Prof. Dr. Wolf-Tilo Balke Bei der Suche in großen Datenbeständen wird traditionell zwischen Daten und Information Retrieval unterschieden. Während Erstere auf relativ leicht durchführbaren Datenvergleichen innerhalb von SQL basiert, erfordert Information Retrieval eine semantische Interpretation. Leider liegen beiden Suchparadigmen unterschiedliche Formalismen zu Grunde, etwa Mengentheorie und Boolesche Werte beim Daten Retrieval und das Vektorraummodell und Scoring-Werte beim Information Retrieval. Für eine semantische Suche werden jedoch beide Suchparadigmen in Kombination benötigt. Leider fehlt bis jetzt ein Anfragesystem, welches diese verschiedenen Suchparadigmen auf der Grundlage einer einheitlichen Theorie miteinander vereinigt. Im Vortrag wird die integrierende Anfragesprache CQQL vorgestellt. Diese vereint die oben genannten verschiedenen Formalismen in einer Theorie, die sich an den Gesetzen der Quantenmechanik und der Quantenlogik orientiert. Es kann gezeigt werden, dass CQQL den relationalen Bereichskalkül um die für eine semantische Suche benötigte Behandlung von Proximity- und IR-Bedingungen erweitert. Weiterhin erfordert eine adäquate Formulierung eines Informationsbedürfnisses (semantische Suche) häufig die Angabe von Gewichten. Ein spezieller Gewichtungsansatz in CQQL ermöglicht die Gewichtung unterschiedlicher Suchbedingungen. Die Gewichte können dabei direkt spezifiziert, aber auch aus Beispieldaten gelernt werden. Im Vortrag wird gezeigt, dass zur Berücksichtigung der Gewichtung die der Sprache CQQL zu Grunde liegende Theorie elegant genutzt werden kann.

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Erinnerung: Vortrag am 22.06.2009, 14:00 Uhr
by Informatik-Kolloquium 21 Jun '09

21 Jun '09

Die Dozenten der Informatik-Institute der Technischen Universität Braunschweig laden im Rahmen des Informatik-Kolloquiums zu folgendem Vortrag ein: Prof Theo Härder, TU Kaiserslautern: Towards Flash Disk Use in Databases - Improving Performance While Saving Energy! Beginn: 22.06.2009, 14:00 Uhr Ort: TU Braunschweig, Informatikzentrum, Mühlenpfordtstraße 23, 1. OG, Hörsaal M 160 Webseite: http://www.ibr.cs.tu-bs.de/cal/kolloq/2009-06-22-haerder.html Kontakt: Prof. Dr. Wolf-Tilo Balke Green computing or energy saving when processing information is primarily considered a task of processor development. We, however, advocate that a holistic approach is necessary to reduce power consumption to a minimum. We explore the potential of NAND flash memory in comparison to magnetic disks for DBMS-based architectures. For this reason, we attempt to identify the IO performance of both storage types at the device level and file system interface, before we approach the most important question how DBMS applications can take advantage of the flash performance characteristics. Furthermore, based on an analysis of storage structures and related benchmark runs in our XTC system, we discuss how IO-intensive DBMS algorithms have to be adjusted to take most out of the flash technology. First results can be reported concerning tailor-made DB buffer management for flash-based databases. The ultimate goal is to substantially improve energy efficiency while comparable performance as in disk-based DB servers is maintained.

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