A reversible and secure patient information hiding system for IoT driven e-health

Internet of things (IoT) coupled with mobile cloud computing has made a paradigm shift in the service sector. IoT-assisted mobile cloud based e-healthcare services are making giant strides and are likely to change the conventional ways of healthcare service delivery. Though numerous approaches for preventing unauthorized access to information exchanged between a mobile phone and cloud platform do exist, but there is no security mechanism to prevent unauthorized access by the cloud administrators. With an aim to ensure security of client data such as Electronic Patient Records (EPR), we propose a novel high-capacity and reversible data hiding approach for securely embedding EPR within the medical images using Optimal Pixel Repetition (OPR). OPR converts every pixel of the input image to a 2 × 2 block to facilitate reversibility by ensuring all the pixels in a 2 × 2 block to have different values. Since a 2 × 2 block is comprised of 4-pixel elements, which could be arranged in sixteen possible ways; we generate a lookup table corresponding to sixteen possible positions of pixels. EPR hiding in each block is achieved by permuting the pixels of a block according to the four-bit word of secret data, resulting in a histogram invariant stego image. The histogram invariance improves the robustness of the proposed scheme to statistical attacks. A stego image is said to hide embedded data securely, when it provides better imperceptivity for an appreciably high payload. Thus, while using information embedding approach for securing client data on a mobile-cloud platform, high imperceptivity is a desirable feature. Experimental results show that average PSNR obtained is 42 dB for payload 1.25 bpp by our scheme, showing its effectiveness for preventing unauthorized access to client’s sensitive data.     

纯物理古籍修补方法——真空修补法

真空修补法是一种纯物理的古籍修补方法,不需要使用浆糊,简单且具有安全性与可逆性,修补后的古籍无需苛刻的收藏条件,使不能流通的古籍变成可以任意翻阅的资料。特别是对于爱好收藏古籍的个人来说,因其不具备图书馆专业的藏书条件,真空修补法是其修补与保存古籍最有效的方法。     

三类复杂系统的比较研究

以统计物理系统、进化生物系统、经济系统等三类复杂的典型系统为背景 ,探讨系统科学的一些基本概念、研究方法。     

再论伴随矩阵的性质

在［1］文的基础上进一步研究了n（n＞2）阶实方阵A的伴随矩阵A*、*A的性质,并对所得的结果给出证明。