U. Dinesh Acharya

Suma D., U. Dinesh Acharya, Geetha M. et al.

Locating and distilling the valuable relevant information continued to be the major challenges of Information Retrieval (IR) Systems owing to the explosive growth of online web information. These challenges can be considered the XML Information Retrieval challenges as XML has become a de facto standard over the Web. The research on XML IR starts with the classical IR strategies customized to XML IR. Later novel IR strategies specific to XML IR are evolved. Meanwhile literatures reveal development of the rapid and intelligent IR systems. Despite their success in their specified constrained domains, they have additional limitations in the complex information space. The effectiveness of IR systems is thus unsolved in satisfying the most. This article attemptsan overview of earlier efforts and the gaps in XML IR.

S. Hemalatha, U. Dinesh Acharya, A. Renuka

Steganography is one of the methods used for secret communication. Steganography attempts to hide the existence of the information. The object used to hide the secret information is called as cover object. Images are the most popular cover objects used for steganography. Different techniques have to be used for color image steganography and grey scale image steganography since they are stored in different ways. Color image are normally stored with 24 bit depth and grey scale images are stored with 8 bit depth. Color images can hold large amount of secret information since they have three color components. Different color spaces namely RGB (Red Green Blue), HSV (Hue, Saturation, Value), YUV, YIQ, YCbCr (Luminance, Chrominance) etc. are used to represent color images. Color image steganography can be done in any color space domain. In this paper color image steganography in RGB and YCbCr domain are compared. The secret information considered is grey scale image. Since RGB is the common method of representation, hiding secret information in this format is not secure.