Softwarearchitektur für die interaktive Simulation mobiler Arbeitsmaschinen in virtuellen Umgebungen

Die numerische Simulation ist ein unverzichtbares Werkzeug bei der Produktentwicklung geworden. Bereits in den frühen Phasen von Studien und Konzepten können unterschiedliche Lösungsansätze für eine Aufgabenstellung bewertet werden. In diesem Zusammenhang wird von virtuellen Prototypen gesprochen. Bei der Simulation mobiler Arbeitsmaschinen erfordert das die Einbindung des Bedieners. Die technologische Leistungsfähigkeit wird wesentlich durch die Interaktion zwischen Bediener und Maschine geprägt. Die Beschreibung des Bedieners durch mathematische Modelle ist bis zum gegenwärtigen Zeitpunkt nicht mit belastbaren Resultaten erfolgt. Die Entwicklungen im Bereich der Simulationstechnologie und der Computergrafik ermöglichen die Durchführung interaktiver Simulationen in komplexen virtuellen Welten. Damit lässt sich der Bediener direkt in die Simulation einbinden und es können zusätzliche Potenziale, wie z. B. bei der Untersuchung der Mensch-Maschine-Interaktion erschlossen werden. Durch die interaktive Simulation in Virtual-Reality-Systemen werden neue Anforderungen an die Simulationssoftware gestellt. Zur Interaktion mit dem Bediener müssen die Eingaben aus den Bedienelementen in Echtzeit verarbeitet und audiovisuelle Ausgaben generiert werden. Dabei sind neben den mathematisch-physikalischen Aspekten der Simulation auch Problemfelder wie Synchronisation, Kommunikation, Bussysteme und Computergrafik zu behandeln. Die Anpassung des Simulationssystems an unterschiedliche Aufgabenstellungen erfordert ein flexibel konfigurierbares Softwaresystem. Als Lösung dieser Aufgabenstellung wird eine Softwarearchitektur vorgestellt, welche die unterschiedlichen Problemfelder durch klar voneinander abgegrenzte Komponenten mit entsprechenden Schnittstellen behandelt. Das entstandene Softwaresystem ist flexibel und erweiterbar. Die Simulationsaufgabe wird durch die Konfiguration des Komponentensystems spezifiziert. Die entstehenden Konfigurationsdateien bilden die Anwendungslogik ab und stellen daher einen der wesentlichen Kostenfaktoren bei der Realisierung interaktiver Simulationen dar. Zur Erhöhung der Wiederverwendbarkeit bestehender Konfigurationsfragmente wird ein kompositionsbasierter Ansatz auf der Basis von Skriptsprachen gewählt.Numerical simulation has evolved into an indispensable tool in modern product development. Even in the early design phases of studies and concepts several different approaches for one individual task can be evaluated. In this context the term virtual prototypes can be used. For effective simulation of mobile construction site machinery incorporation of the operator\'s influence is required. The technological performance of the machinery is essentially influenced by the interaction between the operator and the machine. Currently, there are no known mathematical models describing the operator\'s behaviour, which give substantiated results. The latest developments in computing technology and computer graphics facilitate interactive simulations in complex virtual worlds. This allows not only the operator to be linked to the simulation but also the investigation of additional research areas such as human-machine-interaction. The application of interactive simulation in virtual reality systems places new demands on the simulation software. Due to the interaction not only input signals from the instruments have to be processed but also audio and visual output has to be generated in real time. In addition to the mathematical and physical aspects of simulation, problems in the areas of synchronisation, communication, bus systems and computer graphics also have to be solved. The adaption of the simulation system to new tasks requires a flexible and highly configurable software system. As a response to these demands, a software architecture is presented which partitions the various problems into finite components with corresponding interfaces. The partitioning results in a flexible and extendable software system. The simulation task is specified by the configuration of the component system. The resulting configuration files reflect the application logic and therefore represent one of the main cost factors in the realisation of the interactive simulations. A composition-based approach is chosen as it raises the level of reuse of existing configuration fragments. This approach is based on scripting languages

Glutathione-S-transferase subtypes α and π as a tool to predict and monitor graft failure or regeneration in a pilot study of living donor liver transplantation

<p>Abstract</p> <p>Objective</p> <p>Glutathione-S-Transferase (GST) subtype α and π are differentially expressed in adult liver tissue. Objective of the study was if GST α and p may serve as predictive markers for liver surgery, especially transplantations.</p> <p>Methods</p> <p>13 patients receiving living donor liver transplantation (LDLT) and their corresponding donors were analyzed for standard serum parameters (ALT, AST, gGT, bilirubin) as well as GST-α and -π before LDLT and daily for 10 days after LDLT. Patients (R) and donors (D) were grouped according to graft loss (R1/D1) or positive outcome (R2/D2) and above named serum parameters were compared between the groups.</p> <p>Results</p> <p>R1 showed significantly increased GST-α and significantly lower GST-π levels than R2 patients or the donors. There was a positive correlation between GST-α and ALT, AST as well as bilirubin and a negative correlation to γGT. However, γGT correlated positively with GST-π. Graft failure was associated with combined low GST-π levels in donors and their recipients before living donor liver transplantation.</p> <p>Conclusion</p> <p>Our data suggest that high GST-α serum levels reflect ongoing liver damage while GST-P indicates the capacity and process of liver regeneration. Additionally, GST-π may be useful as marker for optimizing donor and recipient pairs in living donor liver transplantation.</p

Effects of integration time on in-water radiometric profiles

This work investigates the effects of integration time on in-water downward irradiance E-d, upward irradiance E-u and upwelling radiance L-u profile data acquired with free-fall hyperspectral systems. Analyzed quantities are the subsurface value and the diffuse attenuation coefficient derived by applying linear and non-linear regression schemes. Case studies include oligotrophic waters (Case-1), as well as waters dominated by colored dissolved organic matter (CDOM) and non-algal particles (NAP). Assuming a 24-bit digitization, measurements resulting from the accumulation of photons over integration times varying between 8 and 2048ms are evaluated at depths corresponding to: 1) the beginning of each integration interval (FST); 2) the end of each integration interval (LST); 3) the averages of FST and LST values (AVG); and finally 4) the values weighted accounting for the diffuse attenuation coefficient of water (WGT). Statistical figures show that the effects of integration time can bias results well above 5% as a function of the depth definition. Results indicate the validity of the WGT depth definition and the fair applicability of the AVG one. Instead, both the FST and LST depths should not be adopted since they may introduce pronounced biases in E-u and L-u regression products for highly absorbing waters. Finally, the study reconfirms the relevance of combining multiple radiometric casts into a single profile to increase precision of regression products. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement