Requirements and problems in parallel model development at

Nearly 30 years after introducing the first computer model for weather forecasting, the Deutscher Wetterdienst (DWD) is developing the 4th generation of its numerical weather prediction (NWP) system. It consists of a global grid point model (GME) based on a triangular grid and a non-hydrostatic Lokal Modell (LM). The operational demand for running this new system is immense and can only be met by parallel computers. From the experience gained in developing earlier NWP models, several new problems had to be taken into account during the design phase of the system. Most important were portability (including efficieny of the programs on several computer architectures) and ease of code maintainability. Also the organization and administration of the work done by developers from different teams and institutions is more complex than it used to be. This paper describes the models and gives some performance results. The modular approach used for the design of the LM is explained and the effects on the development are discussed

Parallele Strategien für ein spektrales Wolkenmodul in einem 3-dimensionalen Mesoskalenmodell

A spectral cloud model is developed for a 3-dimensional mesoscale model considering only the microphysical conversion processes of the warm cloud. Because of the expected computation requirements, which are strongly increased in relation to the bulk-parameterization, we develop concepts for the parallelization of the module, explain their applicability and present first results.Für ein 3-dimensionales Mesoskalenmodell wird ein spektrales Wolkenmodul entwickelt, das zunächst nur die mikrophysikalischen Umwandlungsprozesse der warmen Wolke berücksichtigt. Aufgrund des zu erwartenden, im Vergleich zur bulk-Parametrisierung stark erhöhten Rechenzeitbedarfs entwickeln wir Konzepte zur Parallelisierung des Moduls, erläutern deren Anwendbarkeit und stellen erste Ergebnisse vor

Extension and optimisation of a communication platform for pc-based control systems

Die vorliegende Arbeit befasst sich mit der Erweiterung und Optimierung einer Kommunikationsplattform für offene PC-basierte Steuerungssysteme für Parallelkinematiken und leistet einen Beitrag dazu, den Umsetzungsaufwand von Steuerungsapplikationen selbst in einer verteilten Umgebung zu reduzieren und gleichzeitig die Performanz und Zuverlässigkeit des Steuerungssystems zu steigern. In Gegensatz zu Seriellen Robotern bestehen Parallelkinematiken aus einer geschlossenen kinematischen Kette, bei dem der Manipulator über mehrere Führungsglieder mit den fest am Gestell montierten Antrieben verbunden ist. Begünstigt durch diese mechanische Struktur resultiert für jeden Antrieb eine gering zu bewegenden Masse pro Verfahrbewegung. Dies wiederum führt dazu, dass im Vergleich zu seriellen Robotern höhere Arbeits¬geschwin¬dig¬keiten und -beschleunigungen bei höherer Genauigkeit und Steifigkeit gefahren werden können. Neben einer Erhöhung der Performanz des Steuerungssystems liefert diese Arbeit die architekturspezifische Grundlage für die Integration von rechenaufwendigen parallelroboterspezifischen Besonderheiten in den Steuerungspfad. Weiterhin schafft diese Arbeit eine Plattform für die Implementierung und Ausführung von echtzeitfähigen verteilten Steuerungsapplikationen. Dafür wird die Middleware so erweitert, dass sie Anwenderapplikationen eine transparente Nutzung von Kommunikations¬mechanismen im verteilten System gewährleistet. Eine optimale Nutzung der verteilten Ressourcen wird durch die Integration eines Self-Managers in die Steuerungssofware erreicht. In diesem Zusammenhang wird im Rahmen dieser Arbeit eine Monitoring-Komponente in die Middleware integriert, die topologische und zeitliche Informationen über die Ausführung von Tasks im verteilten System zur Laufzeit ermittelt und dem Anwender bereitstellt.The present work covers the expansion and optimization of a communication platform designed for the implementation of an open and computer-based control system for parallel kinematics. This work helps to reduce the implementation cost of control applications and increases at the same time the performance of the control system. Unlike serial robots, the mechanical structure of a parallel kinematics consists of a closed kinematic chain. The manipulator is connected over many links to the drives mounted on the rack. Favored by this mechanical structure each drive has a reduced mass to move and therefore higher velocities and accelerations are achievable. In addition to the performance increase of the control system this work provides the architectural fundament for the integration of computationally intensive and parallel kinematics specific features in the control system. Furthermore, the present work provides a platform for the implementation and execution of real-time distributed control applications in both multi-core processors and computer network. In this context, the middleware is extended so that it ensures user applications a transparent using of communication mechanisms in the distributed systems. To ensure optimal use of the resources available in the distributed system a self-manager is integrated into the control system. The self-manager responds independently and efficiently to changes occurring in the system topology as well as to changing demands on the control. It automatically adjusts the distribution of the control modules at runtime. In order to achieve this, a monitoring component is integrated in the middleware. It determines and provides topological and temporal information about the execution of tasks in the distributed system at runtime

Atmospheric pollution transport: the parallelization of a transport & chemistry code

We discuss a model for computing the chemical reactions occurring among air pollutants and predict their dispersion in the atmosphere. We consider a parallel implementation on a CRAY T3D, using up to 128 processors. A regular subdomain decomposition is considered to optimize inter-processor communications, while load balancing Ð the main technical di¦culty to obtain a good e¦ciency Ð is achieved by re-assigning temporarily pieces of work to other processors, according to a global strategy. The performance of our implementation is described by an analytical relation whose validity is checked on realistic data sets. A speedup of 100 is obtained with 128 processors

Entwicklung einer Schnittstelle für verteiltes I/O in einer neuen on-board Computerarchitektur.

This work is a part of the On-Board-Computer Next-Generation (OBC-NG) project by the German Aerospace Centre. The OBC-NG project surveys a concept for distributed computing on space systems. This thesis is about the Interface-Node component which provides access to the sensors and actuators of the space system. At first there will be an overview of existing techniques in the field of distributed systems. Out of this a concept will be developed for use in embedded systems. To evaluate the concept a prototype for a simulation evironment and for embedded systems will be implemented. Based on this implementation the applied techniques will be evaluated for the use in the OBC-NG System. This thesis shows, that techniques which are used in High-Performance-Computing (HPC) Systemd can be adapted to embedded Systems with severe resource restrictions