OptiNum-Grid

Optimisation of technical systems and natural science models with the assistance of numerical grid simulations

Today, the development of innovative, new products in many areas is no longer possible without computer simulations. On the one hand, this is due to increasingly powerful technologies, which are also becoming increasingly complex. On the other hand, the demands placed on product safety guarantees are increasing in all phases of development. The computer service required often exceeds the limits of services that can be provided for the engineers, particularly in small and medium-sized businesses.

In the community project, OptiNum-Grid, businesses from micro-chip development and adaptronics – actively reacting systems for damping vehicle axle vibrations, for example – have joined forces with resource providers and research institutions to carry out the required simulations in the grid. As such, developments that already exist in the German D-Grid initiative are to be expanded in such a way that the grid can be integrated into the developers’ work as cost-effectively as possible. A large part of the OptiNum-Grid developments should also be relevant for simulation problems outside of the community.

Basic services
One of OptiNum-Grid’s objectives is the simplification of software use. Users of simulation software often require very specific software or a precise software version. On occasion, specially developed programs are also used. Usually in the grid it is not possible to predict which computer will carry out a grid job, and the provision of an executable version of a required application on such a computer is a major problem. In the OptiNum-Grid, services are to be developed which will provide users with comprehensive assistance in this matter. Therefore, even a transparent computer change will be simplified, in the event of a computer malfunction, for example.

Other services planned for OptiNum-Grid concern the confidentiality of user data. This important issue is dealt with by a security architecture, with different grades according to requirements. The first level will make it possible for only the respective users to encrypt and decrypt their data with an access key. A further level enables the application to be run in a virtual machine, through which external access to the application memory is made more difficult. Finally, for special applications, encryption and decryption of data will be directly included in the application itself.

Because a combination of a number of programs is often required for processing a simulation problem, a portal and services are provided in the OptiNum-Grid, which enable the generation and processing of corresponding multistage operating sequences (workflows). At the same time, it should also be possible to implement the desired simulations – as far as possible – simultaneously on different systems (parallel processing).

Application-related services
The simulations applications in the OptiNum-Grid are broadly divided into three areas of use: variant simulation, optimisation and validation. During the variant simulation, the objective is to test the changes in behaviour of slightly differing designs, in an optimisation it is to find the best possible settings for determined design characteristics. For validation, the ultimate aim is to determine, through simulations of the readily developed system, whether it possesses the expected characteristics under a variety ofconditions. Overall, the total number of individual simulations required is large in all three cases. However, the workflows of these three broadly assumed areas of use differ from each other. In the OptiNum-Grid, respectively adapted grid services are provided, which simplify the preparation, implementation and evaluation of individual grid simulations for the user.

First of all, the system uses the description of a design and the changing characteristics (input data) to generate the required individual simulation automatically. The next step is the parallel execution of the generated simulations in the grid, where a likewise designed service can be used for the distributed solution to large equation systems. In the case of optimisation, new (improved) input data is then generated by means of the specified evaluation of the simulation results. Finally, the collation of the simulation results and their summary is supported by grid services.

Demonstrations

The services available in OptiNum-Grid are tested by consortium partners’ application scenarios. These application scenarios are developed in the project to the extent that they are available as ready-to-run demonstrations. One demonstration is the simulation of exposure processes in microelectronics. An existing program, designed for local computer networks, is to be adjusted accordingly to the available services, so that it can be run in the grid. Another demonstration is the finite element method (FEM) application, which is of key importance to the simulation of mechanical systems. In this scenario, it focuses primarily on the interface between existing FEM programs and the grid service available, in order to find solutions for large equation systems. A third scenario concerns circuit design. A comparative study will highlight the performance gains achieved by using the OptiNum-Grid services for the optimisation of a complex circuit. Finally, a demonstration will show grid use for validating circuits. In this case, a circuit simulation, written in a hardware description language such as Verilog or VHDL, will be carried out and distributed in the grid and the results will be automatically collated again.