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Your search keyword '"Liu, Dengkai"' showing total 17 results
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17 results on '"Liu, Dengkai"'

4. Spec-ResNet: A General Audio Steganalysis scheme based on Deep Residual Network of Spectrogram

Author

Ren, Yanzhen, Liu, Dengkai, Xiong, Qiaochu, Fu, Jianming, and Wang, Lina

Subjects
Computer Science - Multimedia
Abstract

The widespread application of audio and video communication technology make the compressed audio data flowing over the Internet, and make it become an important carrier for covert communication. There are many steganographic schemes emerged in the mainstream audio compression data, such as AAC and MP3, followed by many steganalysis schemes. However, these steganalysis schemes are only effective in the specific embedded domain. In this paper, a general steganalysis scheme Spec-ResNet (Deep Residual Network of Spectrogram) is proposed to detect the steganography schemes of different embedding domain for AAC and MP3. The basic idea is that the steganographic modification of different embedding domain will all introduce the change of the decoded audio signal. In this paper, the spectrogram, which is the visual representation of the spectrum of frequencies of audio signal, is adopted as the input of the feature network to extract the universal features introduced by steganography schemes; Deep Neural Network Spec-ResNet is well-designed to represent the steganalysis feature; and the features extracted from different spectrogram windows are combined to fully capture the steganalysis features. The experiment results show that the proposed scheme has good detection accuracy and generality. The proposed scheme has better detection accuracy for three different AAC steganographic schemes and MP3Stego than the state-of-arts steganalysis schemes which are based on traditional hand-crafted or CNN-based feature. To the best of our knowledge, the audio steganalysis scheme based on the spectrogram and deep residual network is first proposed in this paper. The method proposed in this paper can be extended to the audio steganalysis of other codec or audio forensics., Comment: 12 pages, 11 figures, 5 tables

Published
2019

14. Stability analysis of surrounding rock of bedding dolomite tunnel with different dip angles

Author

Zhao Xia, Xie Caijin, Song Shuai, Liu Dengkai, Nie Chongxin, Rao Junying, and Liu Ning

Subjects
Bedding, Dolomite, Mineralogy, Geology
Abstract

To investigate the stability of surrounding rock of bedding dolomite tunnels with different dip angles, this study considers the diversity of tunnels in different geological conditions. In the case of five different bedding angles, the effects of different dolomite rock thicknesses, contact interlayer thicknesses, contact interlayer elastic moduli, contact interlayer cohesive forces, and contact interlayer friction angles on tunnel stability are analyzed. When the bedding angle is 22.5°, the surrounding rock displacement is the largest, the peeling between layers is obvious. The plastic zone of the surrounding rock is concentrated in the unsupported area of the tunnel. The contact interlayer has a weakening effect on the displacement of the surrounding rock and the expansion of the plastic zone. The thickness of the dolomite and the thickness of the contact interlayer have different effects on the displacement of surrounding rock of different bedding angles. Increasing the elastic modulus of the contact interlayer can reduce the displacement of the surrounding rock, increasing the internal friction angle of the contact interlayer has less influence on the displacement of the surrounding rock, and increasing the cohesive force of the contact interlayer can reduce the displacement of the surrounding rock.

Published
2019

15. Analytical analysis of stress and displacement for surrounding rock of deep-buried rectangular tunnel in layered strata

Author

Nie Chongxin, Liu Dengkai, Xie Caijin, Li Ping, and Rao Junying

Subjects
Stress (mechanics), Displacement (orthopedic surgery), Geotechnical engineering, Geology
Abstract

This study presents a theoretical solution on stress and displacement of the deep-buried tunnel surrounding rock in layered strata. Based on theory of Покровский equivalent layer method, we convert layered strata into homogeneous ones and then map the rectangular tunnel in the coordinate plane z to the unit circle of complex plane ζ, through using a complex variable method and calculating the analytic functions Φ(ζ) and Ψ(ζ) with Matlab, the study obtains that the stress of the surrounding rock of deep-buried rectangular tunnel in layered strata. Subsequently, we derive the strain and displacement of the surrounding rock. Finally, we study the effects of lateral pressure coefficient and grade of surrounding rock and height-to-width ratio of the tunnel on the stress of tunnel surrounding rock. Based on our analysis, we formulate valuable rules.

Published
2019

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