Fig. 7-1 The flow of data in the present general-purpose real-time visualization system and an example of the operation of the system applied to the prediction system of radioactivity diffusion, (WSPEEDI). The diagram on the right shows the progress of the simulation of diffusion processes of radioactivity emitting from 6 nuclear power plants of East-Asian countries in the event of an accident. The white parts indicate particles representing the radioactivity and the red arrows denote the direction of the wind.

Table 7-1

Quantities of the transmitted data versus the transmission procedure

With increasing number of the grids it becomes clear that the compressed graphic data transmission procedure is advantageous over the direct transmission procedure of the raw simulation results.

With increasing speed of computers and the fulfillment of a network environment the need for high speed and high quality visualization of computational results has increased. This is because our understanding cannot catch up with the vast flow of output data from a simulation unless they are graphically presented. In addition there is a requirement to provide a system by which we can control a simulation run by issuing an order to the computer during the execution of the simulation, on the basis of the graphically presented results. In order to meet the above requirements we developed a general-purpose real-time visualization system on the basis of the following new concepts and the new technology. Firstly, this system provides not only a tracking function by which the simulation results can be visualized at any time during the progress of the simulation run, but also a steering function by which one can control the simulation itself as well as the visualization conditions. Secondly, it is possible that large-scale simulations carried out on various types of large-scale computers, are visualized on different smaller computers (clients). With this in mind, (the connection of large-scale computers to clients) we employed the web technology used for the internet. We can exchange information easily among computers connected to the internet by using web browsers regardless of the kinds of the data-sending and data-receiving computers. Lastly, for the efficient transmission of the visualization data we employed a procedure to send compressed graphic data instead of the usual procedure to directly send the raw data of the simulation results. Using this procedure, substantial reduction in the quantities of transmitted data is attained (Table 7-1). Figure 7-1 shows the flow of the operation of the system.

Reference K. Muramatsu et al., Development of Real-Time Visualization System for Computational Fluid Dynamics on Parallel Computers, JAERI-Data/Code 98-014 (1998).

Select a topic in left column