We proposed a manipulation detection method for interrogation speech. We used a robust fingerprinting method optimized for speech since our intended target is interrogation speech recorded during a police investigation. The fingerprint uses line spectral pairs (LSP) to measure the spectral envelope of the speech, and is coarsely quantized so that the fingerprint will not be altered by small degradation in the signal, but will be altered enough by malicious modifications to the speech content. This fingerprint is embedded in the speech signal using conventional spread-spectrum watermarks. To detect manipulation, the watermarked fingerprint is detected, and compared to the fingerprint extracted from the speech itself. If the fingerprints match within the predetermined tolerance, it can be authenticated to be unaltered. Otherwise, manipulation should be suspected.
This paper proposes an audio watermarking method based on the singular-spectrum analysis (SSA) incorporating with a convolutional neural network (CNN) for parameter estimation. A watermark is embedded into an audio signal by modifying some part of its singular spectrum according to an embedding rule. Such a modified part affects both the robustness of the scheme and sound quality of watermarked signals, and it should be determined appropriately in order to balance the robustness and sound quality. In our previous work, we used a method based on a differential evolution (DE) algorithm to estimate the suitable part. However, it is a time-consuming approach. Therefore, in this work, we replace it with a CNN approach. A dataset used to train the CNN is constructed based on the DE. Experimental results show that the computational time is considerably reduced by 96,923 times. The average bit-error rate is 0.07 when there is no attack, and the sound quality of watermarked signals satisfies three objective evaluation metrics. Also, the proposed scheme could blindly extract the watermark due to the time efficiency of the CNN-based method.
Blockchain is a kind of non-tampered global database which provides digital booklets recording financial transactions and valuables such as birth certificates, asset ownerships, education diplomas, medical procedures, ballots and so on. Among the financial activities, coupons have longtime been used for marketing in business and mobile coupons are replacing paper ones due to the popularity of mobile devices gradually. The strong interactions between people and the use of mobile coupons have together inspired Peer to Peer (P2P) sharing and raised the usage of coupons with peer trusts. Adding bonus feedback mechanisms to mobile coupons may effectively prompt transfers of unused coupons to potential users. The valuable information including contents and feedback bonus in mobile coupons need to be protected against security threats like forgery or tampering. The limitations of storage space, computing power, and transmission bandwidth in mobile devices generally constrain strong protection mechanisms as used in desktop computers. Therefore, in this study, the technique of Hash Chain is combined with the blockchain technology to verify forgery coupons and to enable both storage and transmission of low-computation requirements. Our scheme exemplifies P2P sharing spirit with the nature of highly distribution in blockchain. Verifications are handed by the distributed miners in the P2P environment, which reduces the opportunity of conspiracy among evil-doers. In addition, eavesdroppers have no way to steal valuable information due to the anonymous nature of blockchains so that transmissions are entirely secured in the proposed scheme.
RSSI-based localization technology is widely concerned for WSN node localization. However, this kind of methods has relatively larger localization error, and its localization rate is low. In order to enhance the localization accuracy, the localization error is declined by considering the construction of signal transmission model as well as the ranging process, and a modified weighted centroid localization algorithm is proposed in this paper. The simulation results show that the proposed approach can effectively reduce the three-dimensional node localization error.
Redundant backup system is a common system in the real world, especially in aviation, electromechanics and other fields. Therefore, it is meaningful to give the parameter estimation of redundant systems. Previous research has given some results about the order and failure rate of the redundancy distributed redundant backup system, thus providing consumers with a computed and measurable product reliability calculation method. By using the irreplaceable censored life test, Providing a statistical significance of the estimation formula. However, the properties of estimation are not given and how to improve it. The study gives the estimation properties in probabilistic sense, which is asymptotic convergence in probability. Continue to improve the estimator on variance, so as to achieve asymptotic minimum consistent variance estimation. This ensures that the given estimation formula is available in practice.
