Central Police University

About: Central Police University is a education organization based out in Taoyuan District, Taiwan. It is known for research contribution in the topics: The Internet & Poison control. The organization has 482 authors who have published 725 publications receiving 8358 citations. The organization is also known as: Zhōngyāng Jǐngchá Dàxué.

Adaptive Data Hiding in Edge Areas of Images With Spatial LSB Domain Systems

Abstract: This paper proposes a new adaptive least-significant- bit (LSB) steganographic method using pixel-value differencing (PVD) that provides a larger embedding capacity and imperceptible stegoimages. The method exploits the difference value of two consecutive pixels to estimate how many secret bits will be embedded into the two pixels. Pixels located in the edge areas are embedded by a k-bit LSB substitution method with a larger value of k than that of the pixels located in smooth areas. The range of difference values is adaptively divided into lower level, middle level, and higher level. For any pair of consecutive pixels, both pixels are embedded by the k-bit LSB substitution method. However, the value k is adaptive and is decided by the level which the difference value belongs to. In order to remain at the same level where the difference value of two consecutive pixels belongs, before and after embedding, a delicate readjusting phase is used. When compared to the past study of Wu et al.'s PVD and LSB replacement method, our experimental results show that our proposed approach provides both larger embedding capacity and higher image quality.

Gunshot residue analysis : a review

Abstract: A review of all aspects of analysis associated with gunshot residues is provided. This includes a summary of what both inorganic and organic residues are, how they arise and how they may be collected from a variety of substrates. Ways of processing samples to the point of analysis and the means by which they may be analyzed using a variety of techniques is discussed. The techniques described include SEM/EDX, flameless atomic absorption spectroscopy, neutron activation analysis, energy dispersive X-ray fluorescence and some other less common methods for inorganic residues and gas, high performance liquid and super critical fluid chromatography with speciality detectors including mass spectrometry together with capillary electrophoresis, for organic residues. A summary of how the results of such analyses may be interpreted is discussed under the different analytical techniques.