Signal or image reconstruction has now become a common task in many applications. According to linear algebra perspective, the number of measurements made or the number of samples taken for reconstruction must be greater than or equal to the dimension of signal or image. Also reconstruction follows the Shanon's sampling theorem which is based on the Nyquist sampling rate. The reconstruction of a signal or image using the principle of compressed sensing is an exception which makes use of only few number of samples which is below the sampling limit. Compressive sensing also known as sparse recovery aims to provide a better data acquisition and reduces computational complexities that occur while solving problems. The main goal of this paper is to provide clear and easy way to understand one of the compressed sensing greedy algorithm called Orthogonal Matching Pursuit (OMP). The OMP algorithm involves the concept of overcomplete dictionary that is formulated based on different thresholding methods. The proposed method gives the simplified approach for image denoising by using OMP only. The experiment is performed on few standard image data set simulated with different types of noises such as Gaussian noise, salt and pepper noise, exponential noise and Poisson noise. The performance of the proposed method is evaluated based on the image quality metric, Peak Signal-to-Noise Ratio (PSNR).

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Most of the engineering programs especially computer science have two or more security related subjects, but lack of active learning and practical experience in the classroom. Cryptographic algorithms which solve Security problems relay on specific mathematical areas such as modular arithmetic, probability and number theory. Unfortunately students feel difficulty to follow the concepts due to the underlying sophisticated mathematics; it is necessitating a fundamental change in our curriculum. Interactive pedagogical tools need to be introduced incrementally along with standard content in a way that makes the standard content easier to learn and vice versa. This work describes an interactive visualization tool which helps the student community to understand the mathematical concepts behind public cryptography algorithms using Microsoft Excel Spreadsheet. It is shown how the sophisticated maths can be visualized and implemented and also discussed some of the famous public key algorithms that the students at various level can do with the help of Microsoft Excel Spreadsheet.

Code Division Multiple Access (CDMA) is one of the famous channel access method, mainly used in radio communication technologies. Unfortunately this concept is less understood by the student community due to the lack of understanding the mathematical rules behind it. This paper is intended to provide a linear algebra point of explanation of the concepts behind CDMA. The CDMA concept which was otherwise analyzed in spectral point of view is explained using the orthogonality of the bases. The Microsoft Excel Spread Sheet is used as an aid for the simulation since every one can go deep in to the basic concepts.