No abstract

This paper introduces a computer aided diagnosis (CAD) technique for segmentation of mass in breast ultrasound (BUS) images followed by an efficient classification of the image into benign or malignant one. The presence of speckle noise, low contrast and blurred boundary of mass in a BUS image makes it challenging to determine the mass, which is the region of interest (ROI) in the current work. Detecting an accurate ROI in turn results in efficient feature extraction and classification. In current work, image enhancement and speckle noise reduction are implemented for preprocessing in a simple but efficient way through filtering techniques. The results of the preprocessing stage are as effective as those obtained using traditional speckle reduction anisotropic diffusion (SRAD) algorithm. ROI is then accurately determined on preprocessed image by employing local region based active contour method. BUS images are classified through textural, morphological and histogram oriented feature metrics in this work. The obtained features are dimensionally reduced using principal component analysis (PCA) and classified through support vector machine (SVM) method. The proposed method is tested on several images and found to be very effective having an accuracy of 95.7% with very high specificity and positive predictive value (PPV).

In the present paper we analyze the effects of rotation on the propagation of harmonic plane waves in an unbounded type III thermoelastic media rotating with a uniform angular velocity. Exact analytical solutions of the dispersion relation equations for purely shear and purely dilatational plane waves are obtained after developing the mathematical model. Special cases of very low- and high-frequency values are considered to find the asymptotic expressions of several important characterizations associated with the plane waves propagating inside the medium. Numerical values of the wave characterizations for intermediate values of frequency for varying conductivity rates and varying angles of rotation are also obtained and are plotted graphically. A detailed analysis of the effects of rotation on the propagation of plane waves is presented on the basis of our analytical and numerical results.

The present work is concerned with the solution of a problem on fractional order theory of thermoelasticity for an elastic medium. We investigate the thermoelastic interactions inside the medium by employing the fractional order theory of thermoelasticity, recently advocated by Sherief et al. (Int. J. Solids Struct., 47, 269-275, 2010). State space approach together with the Laplace transform technique is used to obtain the general solution of the problem. The general solution is then applied to three specific problems on an elastic half space, whose boundary is subjected to (i) a thermal shock (i.e., a step input in temperature and zero stress), (ii) a normal load (i.e., a step input in stress and zero temperature change) and (iii) a ramp type increase in temperature and zero stress. To observe the variations of displacement, temperature and stress inside the half-space we compute the numerical values of the field variables for a particular material by utilizing a numerical method of Laplace inversion. The effects of fractional order parameter on the variations of different fields inside the medium are analyzed graphically.

No abstract