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DCT-domain deep convolutional neural networks for multiple JPEG compression classification

SIGNAL PROCESSING-IMAGE COMMUNICATION 2018年 67卷 22-33页

作者： Verma, Vinay Agarwal, Nikita Khanna, Nitin Indian Inst Technol Gandhinagar IITGN Elect Engn Multimedia Anal & Secur MANAS Lab Gandhinagar Gujarat India

With the rapid advancements in digital imaging systems and networking, low-cost hand-held image capture devices equipped with network connectivity are becoming ubiquitous. This ease of digital image capture and sharing is also accompanied by widespread usage of user-friendly image editing software. Thus, we are in an era where digital images can be very easily used for the massive spread of false information and their integrity needs to be seriously questioned. Application of multiple lossy compressions on images is an essential part of any image editing pipeline involving lossy compressed images. This paper aims to address the problem of classifying images based on the number of JPEG compressions they have undergone, by utilizing deep convolutional neural networks in DCT domain. The proposed system incorporates a well designed pre-processing step before feeding the image data to CNN to capture essential characteristics of compression artifacts and make the system image content independent. Detailed experiments are performed to optimize different aspects of the system, such as depth of CNN, number of DCT frequencies, and execution time. Results on the standard UCID dataset demonstrate that the proposed system outperforms existing system for multiple JPEG compression classification and is capable of classifying more number of re-compression cycles than existing systems.

关键词： Image forensics compression forensics Deep convolutional neural network (CNN) JPEG forensics multiple compression Forgery detection

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Authenticity examination of compressed audio recordings using detection of multiple compression and encoders' identification

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FORENSIC SCIENCE INTERNATIONAL 2014年 238卷 33-46页

作者： Korycki, Rafal Internal Secur Agcy Forens Lab PL-00993 Warsaw Poland

Since the appearance of digital audio recordings, audio authentication has been becoming increasingly difficult. The currently available technologies and free editing software allow a forger to cut or paste any single word without audible artifacts. Nowadays, the only method referring to digital audio files commonly approved by forensic experts is the ENF criterion. It consists in fluctuation analysis of the mains frequency induced in electronic circuits of recording devices. Therefore, its effectiveness is strictly dependent on the presence of mains signal in the recording, which is a rare occurrence. Recently, much attention has been paid to authenticity analysis of compressed multimedia files and several solutions were proposed for detection of double compression in both digital video and digital audio. This paper addresses the problem of tampering detection in compressed audio files and discusses new methods that can be used for authenticity analysis of digital recordings. Presented approaches consist in evaluation of statistical features extracted from the MDCT coefficients as well as other parameters that may be obtained from compressed audio files. Calculated feature vectors are used for training selected machine learning algorithms. The detection of multiple compression covers up tampering activities as well as identification of traces of montage in digital audio recordings. To enhance the methods' robustness an encoder identification algorithm was developed and applied based on analysis of inherent parameters of compression. The effectiveness of tampering detection algorithms is tested on a predefined large music database consisting of nearly one million of compressed audio files. The influence of compression algorithms' parameters on the classification performance is discussed, based on the results of the current study. (C) 2014 Elsevier Ireland Ltd. All rights reserved.

关键词： Digital audio authenticity Detection of montage Digital forensics multiple compression MP3 encoder classification MDCT coefficients SVM Discriminant analysis Binary decision tree

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Estimating Previous Quantization Factors on multiple JPEG Compressed Images

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EURASIP JOURNAL ON INFORMATION SECURITY 2021年第1期2021卷 p1-11页

作者： Battiato, Sebastiano Giudice, Oliver Guarnera, Francesco Puglisi, Giovanni Univ Catania Catania Italy Univ Catania iCTLab Srl Catania Italy Univ Cagliari Cagliari Italy

The JPEG compression algorithm has proven to be efficient in saving storage and preserving image quality thus becoming extremely popular. On the other hand, the overall process leaves traces into encoded signals which are typically exploited for forensic purposes: for instance, the compression parameters of the acquisition device (or editing software) could be inferred. To this aim, in this paper a novel technique to estimate "previous" JPEG quantization factors on images compressed multiple times, in the aligned case by analyzing statistical traces hidden on Discrete Cosine Transform (DCT) histograms is exploited. Experimental results on double, triple and quadruple compressed images, demonstrate the effectiveness of the proposed technique while unveiling further interesting insights.

关键词： JPEG compression multiple quantization multiple compression Quantization estimation Image forensics

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Non-ambulatory dogs with cervical intervertebral disc herniation: single versus multiple ventral slot decompression

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AUSTRALIAN VETERINARY JOURNAL 2020年第4期98卷 148-155页

作者： Guo, S. Lu, D. Pfeiffer, S. Pfeiffer, D. U. CityU Vet Med Ctr Hong Kong Peoples R China City Univ Hong Kong Jockey Club Coll Vet Med & Life Sci Kowloon Tong Hong Kong Peoples R China

Objective To evaluate the proportion of non-ambulatory dogs with cervical intervertebral disc herniation (IVDH) in a private clinic and to compare signalment and outcome between those that underwent single or multiple ventral slot decompression (VSD). Design Retrospective cohort study. Methods After screening 43,378 medical records (January 2010-September 2016), those of 185 dogs with non-ambulatory tetraparesis or tetraplegia along with cervical IVDH that had undergone single (123) or multiple (62) VSD were included in this study. Data on signalment, preoperative neurological status, location of affected intervertebral disc(s), time to ambulation and short-term outcome were compared between single and multiple VSD groups. Results The proportion of non-ambulatory dogs with IVDH was 35.3%. The prevalence of non-ambulation was higher in male dogs (0.56%) than in female dogs (0.26%;P < 0.001) and in neutered dogs than in unneutered dogs (0.51% and 0.27%, respectively, P < 0.001). After surgery, 96.2% of the dogs reached ambulatory status. Dogs with multiple IVDH were older than those with single IVDH. Sex, neutering status or size did not affect the outcome or ambulation status postsurgery. The Pekingese was the most commonly affected breed in both groups. There was no difference in the time to reach ambulation and the presence of neurological deficits after surgery between dogs that underwent single and multiple VSD. Conclusions In this cohort, dogs undergoing multiple VSD had a good postoperative outcome, and their short-term functional recovery was equal to that of dogs undergoing single ventral slot compression.

关键词： cervical intervertebral disc herniation dogs multiple compression ventral slot decompression

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Microstructure and Tensile Properties of multiple Compressed CuZn Alloy

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JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE 2016年第10期25卷 4598-4607页

作者： Hu, F. Y. Cao, Q. D. Xiao, J. R. Dong, X. H. Ma, S. J. Zhang, X. P. Nanjing Univ Sci & Technol Sch Mat Sci & Engn Nanjing 210094 Jiangsu Peoples R China Nanjing Univ Sci & Technol Coll Sci Nanjing 210094 Jiangsu Peoples R China Nanjing Univ Sci & Technol Sch Mech Engn Nanjing 210094 Jiangsu Peoples R China

The effects of zinc content, preannealing temperature and time, and a number of compression passes on the microstructure and tensile properties of multiple compressed (MCed) CuZn alloys were studied by the orthogonal experimental design method. The grain size of the CuZn alloys was refined by multiple compression (MC), which improved the ultimate tensile strength and tensile yield strength of the annealed CuZn alloys. The degree of grain refinement increased with decreasing grain size of the annealed materials. Fragmentation of the alpha-Cu and secondary phases during the MC process led to the grain refinement. The zinc content, preannealing temperature and time, and a number of compression passes were therefore found to have a very significant effect on the tensile properties of the MCed material.

关键词： mechanical properties multiple compression microstructure non-ferrous metals orthogonal experimental design thermomechanical processing

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On the elevated-temperature deformation behavior of polycrystalline Cu subjected to predeformation by multiple compression

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MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING 2008年第1-2 C期483-84卷 547-550页

作者： Li, Y. J. Zeng, X. H. Blum, W. Univ Erlangen Nurnberg Inst Werkstoffwissensch D-91058 Erlangen Germany

Strain rate sensitivity of flow stress and creep resistance were studied during creep at elevated temperature of 373 K as function of prestrain in multiple uniaxial compression at room temperature for pure Cu99.99 with initial grain size d approximate to 50 mu m. Moderate prestrains <= 2 strengthen the material by formation of subgrains with low-angle boundaries, while severe prestrains enhance the strain rate sensitivity and soften the material in the saturation state of deformation. The results are discussed in terms of increase of the fraction of high-angle boundaries in the subgrain structure produced by severe prestraining influencing the balance of generation and annihilation of dislocations. (C) 2007 Elsevier B.V. All rights reserved.

关键词： multiple compression strain rate sensitivity creep high-angle boundaries dislocation annihilation

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The Universal Coding Method in the Data compression Algorithm

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AUTOMATIC CONTROL AND COMPUTER SCIENCES 2010年第5期44卷 279-286页

作者： Kasumov, N. K. Azerbaijan Natl Acad Sci Inst Informat Technol Ul F Agaeva 9 AZ-1141 Baku Azerbaijan

A brand new constructive data compression algorithm is considered. The models basic elements are indicated. Data transformation is carried out on the basis of three parameters using binary and decimal numeration systems. Methodical validation of data packing procedures is provided in a generalized form. Step-by-step structural description of the designed model is presented, along with schemes of the logging mechanism and interaction of the algorithms main parts. The problem of combining the universalism principle with supercompression of digital information is approached. Moreover, the model operates in modes of both single and multiple application of the same crypto-graphic scenario. A brief analysis of the model under extreme loads with and without considering the decoding log capacities and stabilizing bit array is carried out. The algorithms excesses and their effect on data coding and decoding processes efficiencies are discovered. Positive and negative aspects of the introduction of log and stabilizing bits into data compression process are indicated. The concept of informations critical volume, which specifies the algorithms operation in the cryptographic generator mode, is defined.

关键词： data compression algorithm universal coding method guaranteed content compression repeated compression multiple compression information's critical volume compression rate

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Three-Criterion Model of Coding as a Guarantee of Lossless compression of Content

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AUTOMATIC CONTROL AND COMPUTER SCIENCES 2007年第5期41卷 294-297页

作者： Kasumov, N. K. Natl Acad Sci Azerbaijan Inst Informat Technol Ul F Agaeva 9 AZ-1141 Baku Azerbaijan

An essentially new algorithm of constructive data compression is considered in the present article. The base components in the operation of the new model are specified. It is shown that procedural evaluation of the data packing procedures in the solution of problems involved in combining the principles of constructivism and guaranteed hyper-reduction in processes of digital information compression is supported on the base of a three-factor model of content transformation.

关键词： lossless data compression guaranteed content compression repeated compression multiple compression critical mass of information degree of compression

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Consolidation mechanisms of pharmaceutical solids: A multi-compression cycle approach

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PHARMACEUTICAL RESEARCH 1997年第8期14卷 1039-1045页

作者： Khossravi, D Morehead, WT DUPONT MERCK PHARMACEUT CO PHARMACEUT RES & DEVEXPT STNWILMINGTONDE 19880

Purpose. The consolidation behavior of various pharmaceutical solids were characterized using compression-cycle profiles. compression-cycle profiles for both uncompacted powder and formed tablets were obtained. These profiles were used to qualitatively and quantitatively characterize the consolidation mechanism of pharmaceutical solids. Methods. An Instron Universal Testing apparatus and a specially instrumented die coupled with a computerized data acquisition system were utilized to measure the upper-punch pressure and the corresponding die-wall pressure during the compression cycle. Results. compression cycle profiles were obtained for a variety of pharmaceutical materials. Based on these profiles, parameters such as hysteresis areas, loading slopes, and unloading slopes were calculated for the materials studied. Conclusions. Materials that consolidate by plastic deformation have similar compression cycle profiles for the first and subsequent compression cycles indicating that the plastic deformation process occurs to the same extent on the first as well as subsequent compression cycles. For brittle materials, the brittle fracture process occurs during the first compression cycle. During subsequent cycles the tabletted material does not undergo further yield or failure and primarily undergoes elastic deformation. Low molecular-weight polyethylene glycol is an excellent model material for plastically deforming materials, whereas sucrose or sodium citrate are excellent examples of materials that consolidate by brittle fracture.

关键词： compression cycle consolidation mechanism plastic deformation brittle fracture multiple compression pharmaceutical excipients

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