Fatigue is inevitable in pipes conveying fluid due to unwanted vibration. Internal resonance occurs in such pipes due to pre-pressure. For the first time, the effects of vibration on the fatigue of fluid-conveying pipes are investigated in this paper. The influences of the internal resonance and the axially functionally graded materials on the fatigue of the pipes are analyzed, aiming at improving mechanical properties and increasing fatigue life. The Galerkin method and the direct multi-scale method are used to construct the solvability condition for the primary resonance and 1:3 internal resonance. Approximate analytical solutions are derived for presenting the nonlinear dynamics of the pipes. The tensile, bending, and resultant stress distribution of the axially functionally graded pipe in internal resonance is determined. The results of the fatigue analysis demonstrate that internal resonance can shorten the fatigue life of axially functionally graded pipes. Reducing the distribution coefficient of functionally graded pipe is beneficial for reducing the resonance response and maximum stress of the pipe conveying fluid. The numerical integration results support the analytical results.

Nonlinear vibration effects on the fatigue life of fluid-conveying pipes composed of axially functionally graded materials

Protecting the personal patient’s information in distributed health infrastructures seems to be a crucial task. As a solution of this issue, image watermarking is widely used to secure and prevent the content alteration. Moreover, it is necessary to find a new blind watermarking technique way that could decrease the latency and preserve the quality of medical images. This paper presents a new watermarking technique for medical image. Our technique consists in combining the DCT transform, Weber descriptors (WDs) and Arnold chaotic map. This combination brings three significant steps. First, the watermark image is scrambled using Arnold chaotic map. Second, the DCT is performed on each medical image block, and the watermark data are embedded in the DCT middle- band coefficients of each block. Finally, a new embedding and extracting technique is proposed, based on WDs without any loss by selecting the right coefficients. We improve the robustness of the proposed algorithm against several scenarios of attacks such as noising, filtering and JPEG compression. The obtained results make our algorithm eligible to be practicable.

A New Blind Medical Image Watermarking Based on Weber Descriptors and Arnold Chaotic Map

In this paper, a novel image zero-watermarking scheme against rotation attacks is proposed based on nonsubsampled pyramid decomposition (NSPD) and discrete cosine transform (DCT) It utilizes the intrinsic characteristics of NSPD and DCT to extract the robust feature of an image as the original zero-watermark To increase the security of the proposed scheme, a variable parameter chaotic mapping (VPCM) is designed for the processes of watermark encryption and robust feature extraction Firstly, the host gray-scale image is decomposed by NSPD, and the low-frequency sub-band image is divided into non-overlapping blocks After the blocks are transformed by DCT, the signs of the first AC coefficients from all the blocks are used to construct a binary feature image Then an exclusive-or operation is performed between the binary feature image and the encrypted watermark image to obtain the verification zero-watermark image Furthermore, a method against arbitrary rotation attacks is employed to improve the robustness of the scheme against geometric attacks The experimental results demonstrate that the proposed scheme is highly robust against various image processing attacks such as filtering, JPEG compression, scaling, translation, rotation and Checkmark attacks

/pdf/a-novel-zero-watermarking-scheme-based-on-variable-parameter-3fhloqhssr.pdf

A Novel Zero-Watermarking Scheme Based on Variable Parameter Chaotic Mapping in NSPD-DCT Domain

This paper proposes a novel robust image watermarking scheme in Discrete Cosine Transform (DCT) domain for active forensics. We investigate the relation between the positions and the modification magnitudes of DCT coefficients and directions of texture blocks. By exploring such relation, a direction-coefficient mapping is designed. First, the texture direction of each image block is estimated by Gabor filter. And then, according to the direction-coefficient mapping, one watermark bit is embedded into each block along its texture direction. Compared with existing schemes, the proposed method utilizes the direction features of texture blocks better . Therefore, the improvements in watermarked image quality and the robustness of watermark signal against image processing attacks are both achieved.

A robust image watermarking scheme in DCT domain based on adaptive texture direction quantization

https://pure.ulster.ac.uk/ws/files/71361339/FGCS_authentication_final_v9.pdf

Protection of Records and Data Authentication based on Secret Shares and Watermarking

Zero-watermarking is a blind digital watermarking method It has reached the point where the robustness and the imperceptibility can arrive at a good balance In this paper, a strong robust zero-watermarking scheme is proposed which employs multiresolution and multiscale representation characteristics of nonsubsampled shearlet transform to analyze the direction features of the given image The effectiveness of the proposed scheme for dealing with many kinds of attack such as compression, noise addition, and scaling is demonstrated by the experimental results When compared with other zero-watermarking schemes using counterpart transforms like discrete wavelet transform, the experimental results show that the proposed watermarking scheme can get better performance

/pdf/a-strong-robust-zero-watermarking-scheme-based-on-shearlets-shwuvf2zm5.pdf

A Strong Robust Zero-Watermarking Scheme Based on Shearlets’ High Ability for Capturing Directional Features

Digital watermarking is a technique used to protect an author’s copyright and has become widespread due to the rapid development of multimedia technologies. In this paper, a novel watermarking algorithm using the nonsubsample shearlet transform is proposed, which combines the directional edge features of an image. A shearlet provides an optimal multiresolution and multidirectional representation of an image based on distributed discontinuities such as edges, which ensures that the embedded watermark does not blur the image. In the proposed algorithm, the nonsubsample shearlet transform is used to decompose the cover image into directional subbands, where different directional subbands represent different directional and textured features. The subband whose texture directionality is strongest is selected to carry the watermark and is thus suitable for the human visual system. Next, singular value decomposition is performed on the selected subband image. Finally, the watermark is embedded in the singular value matrix, which is beneficial for the watermarking robustness and invisibility. In comparison with related watermarking algorithms based on discrete wavelet transforms and nonsubsample contourlet transform domains, experimental results demonstrate that the proposed scheme is highly robust against scaling, cropping, and compression.

/pdf/texture-directionality-based-digital-watermarking-in-4c4s9o8pqd.pdf

Texture Directionality-Based Digital Watermarking in Nonsubsample Shearlet Domain

With the rapid development of information technology, medical images have been extensively exchanged among hospitals and clinics through networks. Furthermore, doctors can share the patients’ images among medical groups. Hence protecting the privacy of the patients’ information is a very important issue. Image sharing technique that does not need complex computation can divide an image into different shares and submit to different protectors. No one can reveal the original image by partial shares. Collecting all shares can completely recover the original image. Hence Image sharing technique can be used to protect the privacy of the patients’ information. This paper proposes a meaningful image sharing method for protecting the security of medical images. Experimental results show that the proposed method is superior to other works.

Wanru Zhang

Papers

A Strong Robust Zero-Watermarking Scheme Based on Shearlets’ High Ability for Capturing Directional Features

Texture Directionality-Based Digital Watermarking in Nonsubsample Shearlet Domain

A New Secret Sharing Digital Image Scheme Based on Boolean