Although the shape of the failure rate function plays an important role in repair and replacement strategies, the mean residual life (mrl) function is more relevant as the latter summarizes the entire residual life function, whereas the former considers only the risk of instantaneous failure. In this paper, we give a review of the different partial ordering results related tomrlorder, andproportional mrlmodel, with some characterization results. Some properties of theshifted mrlorder have been developed along with the closure of theshifted mrlorder under mixture-type operation. We show that redundancy at the component level is not superior to that at the system level, even when the lifetimes of the original and the spare components are iid, although it is well known that the result holds for usual stochastic order. Theshifted mrlorder is characterized in terms of the DMRL class. Some other characterizations are also presented here followed by the closure of the order under Poisson shock model.

A novel scheme for board level fault diagnosis based on cellular automata array (CAA) is presented. In the proposed diagnosis scheme, the output responses of the chips are encoded by applying the strategy of CA-based byte error correcting code. The encoded response symbols for different test vectors are compressed to a signature. The decoding scheme of byte error correcting code is subsequently employed to detect the faulty chips on the board. The CAA-based design for the fault diagnosis strategy results in a simple and modular test structure that is well suited for VLSI implementation. The scheme can be applied for testing and diagnosis of multichip modules (MCMs) as well.

Analytical study of three neighbourhood two state per cell Cellular Automata (CA) behaviour is a comparatively recent phenomenon. A wide variety of applications have been developed utilizing the elegant structure of group CA. In this paper some of the characterizations of the state transition behaviour of non-group CA are reported. These results are subsequently utilized to develop an efficient parallel scheme for image compression. The experimental results confirms compression ratio of the CA based scheme is of the same order as that of JPEG coding.