Matthias Ludwig

DANUBIA: AN INTEGRATIVE SIMULATION SYSTEM FOR GLOBAL CHANGE RESEARCH IN THE UPPER DANUBE BASIN

We describe the concepts and design principles of the integrative simulation system DANUBIA, which supports the analysis of water-related global change scenarios in the Upper Danube Basin. DANUBIA provides an Internet-based platform integrating the distributed simulation models of all socioecological and natural science disciplines taking part in the GLOWA-Danube project, which is part of the German Programme on Global Change in the Hydrological Cycle. As a result of coupled simulations, transdisciplinary effects of mutually dependent processes can be analyzed and evaluated. Actually 13 simulation models of meteorology, land surface, water research, and social sciences are integrated in the DANUBIA system. The development of DANUBIA is based on object-oriented software engineering and Web engineering methods and on the Unified Modeling Language (UML), which is used by all partners as a common graphical notation for modeling the integrative aspects of the system. We describe how the mutually exchanged information between components is modeled and documented by interfaces, we discuss spatial aspects and show how simulation areas are represented, and we consider temporal aspects and describe the coordination of local models by a global time controller which constitutes the heart of any integrative DANUBIA simulation. Finally, we provide an overview of the architecture of the DANUBIA implementation that has been realized in Java. The implementation integrates a wrapper framework that hides the technical details of network communications.

Asymmetric Synthesis and Enantioselectivity of Binding of 1‐Aryl‐1,2,3,4‐tetrahydroisoquinolines at the PCP Site of the NMDA Receptor Complex

A new method for the asymmetric synthesis of 1-substituted tetrahydroisoquinolines is presented. It is based on stereoselective addition reactions of organometallic compounds to the intermediate N-acyliminium ion 6, which is provided with an N-acyl group as a chiral auxiliary. In addition reactions with organomagnesium and organozinc reagents diastereoselectivities from 70:30 to 95:5 (for 7/8) were observed with the zinc reagents in general leading to markedly improved stereoselectivities. By catalytic hydrogenation of 7 and 8 and after removal of the chiral auxiliary the target compounds 11 and 12 were obtained. The enantiomerically pure 11c–g and 12c–g (ee > 99 %), 1-aryl-tetrahydroisoquinolines, were evaluated for their affinity to the PCP [1-(1-phenylcyclohexyl)piperidine] binding site of the NMDA (N-methyl D-aspartate) receptor. In each case the enantiomers 11 exhibited a higher affinity than those of 12, with the potencies of the enantiomers differing by a factor of 4 (11/12g) to 27 (11/12c). The absolute configuration of the more potent enantiomers 11 is in accordance with the stereochemical requirement found for FR115427 (3) which is a close analogue.

Property-driven development of a coordination model for distributed simulations

The coordination of time-dependent simulation models is an important problem in environmental systems engineering. We propose a solution based on a rigorous formal modelling of the participating processes. Methodologically, our approach is driven by property processes which are used for the formal specification of the coordination problem. Property processes are supported by the CSP-like language FSP of Magee and Kramer which will be used throughout this paper for modelling the system requirements and the system design. The heart of our design model is a global time controller which coordinates distributed simulation models according to their local time scales. We will show with model checking techniques that all safety and liveness requirements are guaranteed by the timecontroller design. The strong practical relevance of the approach is ensured by the fact that our strategy is used to produce a formally verified design for the kernel of the integrative simulation system DANUBIA developed within the GLOWA-Danube project.

The absolute configuration of (1S)-(+)- and (1R)-(−)-1-phenyl-1,2,3,4-tetrahydroisoquinoline. A revision of the literature assignment

Abstract The title compounds (S)-(+)- 8 and (R)-(−)- 8 have been prepared by an asymmetric synthesis that is based on stereoselective additions to the chiral N-acylisoquinoliniumion3. The absolute configuration of these compounds has been determined by an X-ray analysis performed on the intermediate 5. According to the results of this study the stereochemical assignment for (S)-(+)- 8 and (R)-(−)- 8 described in the literature has to be revised.

DANUBIA: A Web-Based Modelling and Decision Support System to Investigate Global Change and the Hydrological Cycle in the Upper Danube Basin

We describe architecture and design principles of the integrative modelling and simulation system DANUBIA. The system integrates the distributed simulation models of the socio-economic and natural science disciplines of the GLOWA-Danube project. During an integrative simulation the simulation models run in parallel and exchange iteratively data. The validity of the exchanged data with respect to model time is guaranteed by a central time controller which coordinates the single simulation models. The consistency of spatial data is ensured through the common proxel concept used by all models. The development of DANUBIA is based on object-oriented software engineering methods. A generic framework architecture has been constructed which implements general rules for the behaviour of all simulation models. It can be specialised and thus instantiated by concrete simulation models. We also have developed a particular framework for the socio-economic deep actor models.

View-based development of a simulation framework for multi-disciplinary environmental modelling

We report on the development of a large-scale simulation framework for environmental modelling. The framework allows to couple various simulation models from natural and social science disciplines to perform integrative simulations. It has been constructed following a development methodology based on the identification of different functional views, which are concerned with data exchange, simulation space and coordination of distributed simulation models with respect to (logical) simulation time. On all levels of the development we have rigorously applied modelling and specification techniques including the last step, in which the different views are integrated into a component model of the full framework. The requirements for the correct coordination of simulation models have been formally specified in terms of the process algebra FSP and the design model has been model checked against the coordination requirements. Within the GLOWA-Danube project the framework has been successfully instantiated to construct the distributed simulation system Danubia which integrates up to 15 simulation models from various disciplines to model the consequences of global climate change for the water household on regional scales.