RISS 검색 - 국내학술지논문

무료
기관 내 무료
유료

내보내기
내책장담기
한글로보기

정확도순

내림차순

내림차순

10개씩 출력

1
Reversible Data Hiding in JPEG Images

Fangjun Huang,Xiaochao Qu,Hyoung Joong Kim,Jiwu Huang Institute of Electrical and Electronics Engineers 2016 IEEE transactions on circuits and systems for vide Vol.26 No.9
- 원문보기
<P>Among various digital image formats used in daily life, the Joint Photographic Experts Group (JPEG) is the most popular. Therefore, reversible data hiding (RDH) in JPEG images is important and useful for many applications such as archive management and image authentication. However, RDH in JPEG images is considerably more difficult than that in uncompressed images because there is less information redundancy in JPEG images than that in uncompressed images, and any modification in the compressed domain may introduce more distortion in the host image. Furthermore, along with the embedding capacity and fidelity (visual quality), which have to be considered for uncompressed images, the storage size of the marked JPEG file should be considered. In this paper, based on the philosophy behind the JPEG encoder and the statistical properties of discrete cosine transform (DCT) coefficients, we present some basic insights into how to select quantized DCT coefficients for RDH. Then, a new histogram shifting-based RDH scheme for JPEG images is proposed, in which the zero coefficients remain unchanged and only coefficients with values 1 and -1 are expanded to carry message bits. Moreover, a block selection strategy based on the number of zero coefficients in each 8 × 8 block is proposed, which can be utilized to adaptively choose DCT coefficients for data hiding. Experimental results demonstrate that by using the proposed method we can easily realize high embedding capacity and good visual quality. The storage size of the host JPEG file can also be well preserved.</P>
2
Ciphertext policy attribute-based encryption supporting unbounded attribute space from R-LWE

( Zehong Chen ),( Peng Zhang ),( Fangguo Zhang ),( Jiwu Huang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.4
- 원문보기 2
  ScienceON
  
  KISS
Ciphertext policy attribute-based encryption (CP-ABE) is a useful cryptographic technology for guaranteeing data confidentiality but also fine-grained access control. Typically, CP-ABE can be divided into two classes: small universe with polynomial attribute space and large universe with unbounded attribute space. Since the learning with errors over rings (R-LWE) assumption has characteristics of simple algebraic structure and simple calculations, based on R-LWE, we propose a small universe CP-ABE scheme to improve the efficiency of the scheme proposed by Zhang et al. (AsiaCCS 2012). On this basis, to achieve unbounded attribute space and improve the expression of attribute, we propose a large universe CP-ABE scheme with the help of a full-rank differences function. In this scheme, all polynomials in the R-LWE can be used as values of an attribute, and these values do not need to be enumerated at the setup phase. Different trapdoors are used to generate secret keys in the key generation and the security proof. Both proposed schemes are selectively secure in the standard model under R-LWE. Comparison with other schemes demonstrates that our schemes are simpler and more efficient. R-LWE can obtain greater efficiency, and unbounded attribute space means more flexibility, so our research is suitable in practices.
3
Effect of Precipitate State on Mechanical Properties, Corrosion Behavior, and Microstructures of Al–Zn–Mg–Cu Alloy

Xiaoyan Peng,Yao Li,Guofu Xu,Jiwu Huang,Zhimin Yin 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.5
- 복사/대출신청
The mechanical properties, corrosion behavior and microstructures of the Al–Zn–Mg–Cu alloy under various ageing treatmentswere investigated comparatively. The results show that the tensile strength and corrosion resistance are stronglyaff ected by the precipitate state. Massive fi ne intragranular precipitates contribute to high strength. Discontinuous coarsegrain boundary precipitates containing high Cu content, as well as the narrow precipitate free zone, result in low corrosionsusceptibility. After the non-isothermal ageing (NIA) treatment, the tensile strength of 577 MPa is equivalent to that of579 MPa for the T6 temper. Meanwhile, the stress corrosion susceptibility r tf and the maximum corrosion depth are 97.8%and 23.5 μm, which are comparable to those of 92.8% and 26.7 μm for the T73 temper. Moreover, the total ageing timeof the NIA treatment is only 7.25 h, which is much less than that of 48.67 h for the retrogression and re-ageing condition.