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A quantitative evaluation and analysis method has been proposed for partially diagnosable discrete event systems. It is based on the fault model which is depicted as a tree structure in this paper. Two quantitative indicators as diagnosable degree and diagnosable depth have been introduced to evaluate the diagnosability of systems on aspects of diagnosable fault coverage range and diagnosis precision respectively. The quantitative values of the evaluation result can be used to analyze and compare different systems which are all partially diagnosable. Furthermore, the impact of different structures of fault model on diagnosable degree and diagnosable depth has been discussed. The results of analysis and discussion on an example show that the diagnosable degree and diagnosable depth indicators can reflect the diagnosable status of the system accurately when the system is partially diagnosable.

A simple, high-efficient and energy saving image coding scheme is proposed in this paper, which is suitable for wireless multimedia sensor network. The scheme is based on lifting wavelet transform and SPIHT algorithm. To solve the very low executing efficiency problem of the combined algorithm, we make improvements in two aspects. Firstly, by eliminating the computation and coding of the outmost high-pass coefficients, the energy consumption of the transform is reduced and the execution is speed up. Secondly, by using optimized quantization truncation pretreatment with high-pass subband coefficients, it is avoided that coding mass of small value coefficients of the high-pass subbands, which further improves the executing efficiency. The simulation results show up to 90% reduction in the executing time is achieved by choosing the optimized truncation threshold, with the guarantee for the image quality of 34.5dB.