MFIRE, an underground mine fire simulation program developed in 1980＇s, is a tool that can be used to simulate the impacts of a mine fire event to a mine ventilation network. However, the lack of the abilities to sim...MFIRE, an underground mine fire simulation program developed in 1980＇s, is a tool that can be used to simulate the impacts of a mine fire event to a mine ventilation network. However, the lack of the abilities to simulate some of the important mine fire phenomena realistically hindered its wide applications. This research carried out to improve and upgrade the MFIRE 2.20 program to MFIRE 2.30. The new additions of MFIRE 2.30 including a time dependent fire model, smoke rollback prediction, the incorporation of a moving fire source, and a rewriting of MFIRE in Microsoft Visual C＋＋ were interpreted.展开更多
In this paper, a secure and incidental distortion tolerant signature method for image authentication is proposed. The generation of authentication signature is based on Hotelling＇s T-square Statistic （HTS） via Prin...In this paper, a secure and incidental distortion tolerant signature method for image authentication is proposed. The generation of authentication signature is based on Hotelling＇s T-square Statistic （HTS） via Principal Component Analysis （PCA） of block DCT coefficients. HTS values of all blocks construct a unique and stable ＂block-edge image＂, i.e, Structural and Statistical Signature （SSS）. The characteristic of SSS is that it is short, and can tolerate contentpreserving manipulations while keeping sensitive to content-changing attacks, and locate tampering easily. During signature matching, the Fisher criterion is used to obtain optimal threshold for automatically and universally distinguishing incidental manipulations from malicious attacks. Moreover, the security of SSS is achieved by encryption of the DCT coefficients with chaotic sequences before PCA. Experiments show that the novel method is effective for authentication.展开更多
文摘MFIRE, an underground mine fire simulation program developed in 1980＇s, is a tool that can be used to simulate the impacts of a mine fire event to a mine ventilation network. However, the lack of the abilities to simulate some of the important mine fire phenomena realistically hindered its wide applications. This research carried out to improve and upgrade the MFIRE 2.20 program to MFIRE 2.30. The new additions of MFIRE 2.30 including a time dependent fire model, smoke rollback prediction, the incorporation of a moving fire source, and a rewriting of MFIRE in Microsoft Visual C＋＋ were interpreted.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos.60473002 and 60302028the Beijing Science and Technology Planning Program of China(D0106008040291).
文摘In this paper, a secure and incidental distortion tolerant signature method for image authentication is proposed. The generation of authentication signature is based on Hotelling＇s T-square Statistic （HTS） via Principal Component Analysis （PCA） of block DCT coefficients. HTS values of all blocks construct a unique and stable ＂block-edge image＂, i.e, Structural and Statistical Signature （SSS）. The characteristic of SSS is that it is short, and can tolerate contentpreserving manipulations while keeping sensitive to content-changing attacks, and locate tampering easily. During signature matching, the Fisher criterion is used to obtain optimal threshold for automatically and universally distinguishing incidental manipulations from malicious attacks. Moreover, the security of SSS is achieved by encryption of the DCT coefficients with chaotic sequences before PCA. Experiments show that the novel method is effective for authentication.
