The protection device with low price and high maintenance cost can be used for a long time. In order to improve availability of protection system,a method of increasing redundancy and periodic replacement is proposed....The protection device with low price and high maintenance cost can be used for a long time. In order to improve availability of protection system,a method of increasing redundancy and periodic replacement is proposed. Firstly,the equivalent model of cumulative failure probability was established. Then,the wasting time of the spare part is converted into the working time of the using part.Considering the optimization objective,under the strategy of block replacement, the availability model in infinite period with the maximum availability and the cost model in finite period with the minimum cost are established separately. In this case,we seek out the optimum replacement interval and verify the applicability and validity of the model through contrast and analysis. Finally,the paper gives a brief discussion of future research area about warm standby system maintenance.展开更多
To improve the watermark benchmarks database,a new BRA(Block Replacement Attack)method is introduced in this paper.Unlike the typical BRA which exploits the self-similarity among blocks in image,the scheme utilizes th...To improve the watermark benchmarks database,a new BRA(Block Replacement Attack)method is introduced in this paper.Unlike the typical BRA which exploits the self-similarity among blocks in image,the scheme utilizes the self-similarity in various scale and orientation bands in the wavelet domain of the image.They search the replacement blocks from the blocks of the smaller sub-image at the next lower resolution.The most important advantage of this scheme is that the pyramid sub-band decomposition acts as an automatic block classifier,with the result of simplifying the block search and block matching procedures and thus making the block replacement more effective.Furthermore,an improved algorithm based on Fuzzy set theory is introduced in which the number of blocks chosen for combination are modified adaptively to obtain the candidate replacement blocks.It simplifies the procedure for searching the candidate replacement blocks.These advantages are confirmed by the experimental results,which show that the performance of the scheme is superior to typical BRA methods.展开更多
文摘The protection device with low price and high maintenance cost can be used for a long time. In order to improve availability of protection system,a method of increasing redundancy and periodic replacement is proposed. Firstly,the equivalent model of cumulative failure probability was established. Then,the wasting time of the spare part is converted into the working time of the using part.Considering the optimization objective,under the strategy of block replacement, the availability model in infinite period with the maximum availability and the cost model in finite period with the minimum cost are established separately. In this case,we seek out the optimum replacement interval and verify the applicability and validity of the model through contrast and analysis. Finally,the paper gives a brief discussion of future research area about warm standby system maintenance.
基金the Science Research Plan of Education Office of Shaanxi Province,China under Grant No. 11JK1048Science Research and Development Program Project of Shaanxi Province,China under Grant No. 2011K17-04-01
文摘To improve the watermark benchmarks database,a new BRA(Block Replacement Attack)method is introduced in this paper.Unlike the typical BRA which exploits the self-similarity among blocks in image,the scheme utilizes the self-similarity in various scale and orientation bands in the wavelet domain of the image.They search the replacement blocks from the blocks of the smaller sub-image at the next lower resolution.The most important advantage of this scheme is that the pyramid sub-band decomposition acts as an automatic block classifier,with the result of simplifying the block search and block matching procedures and thus making the block replacement more effective.Furthermore,an improved algorithm based on Fuzzy set theory is introduced in which the number of blocks chosen for combination are modified adaptively to obtain the candidate replacement blocks.It simplifies the procedure for searching the candidate replacement blocks.These advantages are confirmed by the experimental results,which show that the performance of the scheme is superior to typical BRA methods.
