A concurrent test architecture for massively parallel computers andits error detection capability

Presents new principles for online monitoring in the context of multiprocessors (especially massively parallel processors) and then focuses on the effect of the aliasing probability on the error detection process. In the proposed test architecture, concurrent testing (or online monitoring) at the system level is accomplished by enforcing the run-time testing of the data and control dependences of the algorithm currently being executed on the parallel computer. In order to help in this process, each message contains both source and destination addresses. At each message source, the sequence of destination addresses of the outgoing messages is compressed on a block basis. At the same time, at each destination, the sequence of source addresses of all incoming messages is compressed, also on a block basis. Concurrent compression of the instructions executed by the PEs is also possible. As a result of this procedure, an image of the data dependences and of the control flow of the currently running algorithm is created. This image is compared, at the end of each computational block, with a reference image created at compilation time. The main results of this work are in proposing new principles for the online system-level testing of multiprocessor systems, based on signaturing and monitoring the data dependences together with the control dependences, and in providing an analytical model and analysis for the address compression process used for monitoring the data routing process     

Numerical modelling and experimental investigation of the fluid flow and contaminant dispersion in a channel

This paper presents results of both a computational and a physical model of the fluid and mass transport processes in a straight channel with flow control obstructions being placed in the channel. The numerical model employs a three-dimensional CFD simulation incorporating turbulent models for the fluid and mass transport in the channel. The experimental investigations provide the necessary boundary conditions and validation data for the computational model. Large recirculating flows are observed in both the numerical and experimental investigations. Salt solutions have been used in the experimental investigations for the contaminant transport and the dispersion of the salt solution in the channel has been studied numerically. We have obtained reasonably good agreement between the numerical predictions and the experimental observations for both the fluid flow and the mass transport processes.