Showing papers in "IETE Journal of Education in 2014"
TL;DR: Various pixel-based techniques for image forgery detection, mainly copy-move and splicing techniques are discussed.
Abstract: With the advancement of the digital image processing software and editing tools, a digital image can be easily manipulated. The detection of image manipulation is very important because an image can be used as legal evidence, in forensics investigations, and in many other fields. The pixel-based image forgery detection aims to verify the authenticity of digital images without any prior knowledge of the original image. There are many ways for tampering an image such as splicing or copy-move, resampling an image (resize, rotate, stretch), addition and removal of any object from the image. In this paper we have discussed various pixel-based techniques for image forgery detection, mainly copy-move and splicing techniques.
108 citations
TL;DR: The minimal realization of logic function using TT is dealt with, in which TT is reduced successively by one variable at a time till all the variables are exhausted, and definitely leads to the minimal function.
Abstract: In the conventional method, a truth table (TT) is prepared from the specified logic function. Then it is expressed as the sum of min terms corresponding to the rows in which 1 appears. Finally, this function is further reduced using the Boolean identities. Thus, all the simplifications are concentrated at one place after the TT. This procedure does not always lead to the minimal realization. This paper deals with the minimal realization of logic function using TT in which TT is reduced successively by one variable at a time till all the variables are exhausted. The simplification is carried out, instead at the end of the truth table, at the end of each step of TT reduction. The method is shown to be systematic, and definitely leads to the minimal function. It is simpler in operation than that based on only Boolean identities, Karnaugh map and Quine-McClusky methods, and can handle any number of variables. It is explained with several examples. It is worth introducing as an improvement over the cla...
8 citations
TL;DR: In this paper, the authors present a virtual laboratory for testing a single-phase power transformer using MATLAB Simulink environment, which is a typical rating for transformers usually employed for practical classes in the Electrical Machine Laboratory for undergraduate courses.
Abstract: This paper presents a virtual laboratory for testing a single-phase power transformer using MATLAB Simulink environment. The models presented herein replicate the actual tests like no-load test, short-circuit test, load test, and short heat run test successfully well within tolerable accuracy. The rating of the transformer is taken to be 2 kVA, 230/115 V, 50 Hz which is a typical rating for transformers usually employed for practical classes in the Electrical Machine Laboratory for undergraduate courses. This model is attractive to students and they are able to gain insights into operational aspects of a single-phase power transformer. This model, in whole or part, may also be used as final year projects of engineering undergraduate students.
7 citations
TL;DR: The purpose of this chapter is to bring to the attention of students and teachers of circuit theory, as well as of practising design engineers, a recently reported technique for impedance matching at multiple frequencies that has the advantages of design by synthesis, elegance and simplicity.
Abstract: The purpose of this chapter is to bring to the attention of students and teachers of circuit theory, as well as of practising design engineers, a recently reported technique for impedance matching at multiple frequencies. This will be done through a specific example, namely that of design of a lumped network for matching a given load resistance RL to a given source resistance RS at three given frequencies ω1, ω2 and ω3. The method is based on the application of the frequency transformation technique, commonly used in analog filter design, to a basic single-frequency matching network. By comparison with the existing approach of assuming a network configuration and solving a set of simultaneous equations, as reported in a recent paper, the new method is shown to have the advantages of design by synthesis, elegance and simplicity. Further, by virtue of the synthesis approach, the method allows a number of alternative networks to be designed, so that the best one can be selected on the basis of a predetermined criterion.
6 citations
TL;DR: In this paper, the field solutions of rectangular waveguides are obtained mostly through the analysis of underlying physics; this approach provides a firm conceptual grasp over the subject and is best suited to accomplish pedagogical objectives along with being a supplementary text for undergraduate studies.
Abstract: Customarily, the field solutions of rectangular waveguides are achieved by solving Maxwell's equation for three-dimensional vector space. The field expressions obtained from the solutions of differential equations are often too mathematical to develop any physical understanding of the subject. In this article, the field solutions are obtained mostly through the analysis of underlying physics; this approach provides a firm conceptual grasp over the subject and is best suited to accomplish pedagogical objectives along with being a supplementary text for undergraduate studies.
5 citations
TL;DR: In this article, a systematic method combining graphical, analytical, and numerical techniques is presented for finding the roots of a polynomial P0(s) of any degree, where real roots are first found by a simple graphical method, and then the purely imaginary roots are found by the Hurwitz test.
Abstract: A systematic method, which combines graphical, analytical, and numerical techniques, is presented for finding the roots of a polynomial P0(s) of any degree. Real roots are first found by a simple graphical method, and then the purely imaginary roots are found by the Hurwitz test. When all the real and purely imaginary roots are removed from P0(s), the remainder polynomial P2(s) will have only complex conjugate roots and hence will be of even degree. When this degree is 2, the roots are obvious. For P2(s) of degree 4, a variation of a previously published analytical method, combined with a graphical display, is presented which is easier to apply. When the degree of P2(s) is greater than 4, only numerical methods have to be used.
4 citations
TL;DR: In this paper, a modified Hay and Schering bridge for the measurement of quality and dissipation factors respectively is reviewed and the accuracy and resolution are improved not only because of the digital display but also due to the amplification of one of the voltages that appears in the ratio.
Abstract: Conventional Hay and Schering bridges for the measurement of quality and dissipation factors respectively are reviewed. They require calibrated decade boxes which are costly. After the bridge is balanced manual calculations are carried out to evaluate the two factors. In the proposed modified method these drawbacks are removed and the accuracy of measurement is enhanced using digital voltage ratio meter. The method allows the uncalibrated elements which are cheaper than the calibrated ones. Manual calculations are totally eliminated. The accuracy and resolution are improved not only because of the digital display but also due to the amplification of one of the voltages that appears in the ratio.
2 citations
TL;DR: In this article, an exact analysis of finite gain inverting voltage amplifiers using current feedback operational amplifiers (CFOA) for use as stand-alone amplifiers or for being used in second-order active resistance capacitance (RC) filters such as Tow-Thomas biquads is presented.
Abstract: In this paper, we present an exact analysis of finite gain inverting voltage amplifiers using current feedback operational amplifiers (CFOA) for use as stand-alone amplifiers or for being used in second-order active resistance capacitance (RC) filters such as Tow–Thomas biquads. The proposed circuits require one or two additional CFOAs/resistors/capacitors. The effect of finite output impedance at z terminal, input resistance at x terminal, and current mirror pole of the CFOA are studied. The circuits considered have been simulated using PSPICE using a behavioural macro-model of the CFOA as well as that of a practical CFOA AD 844.
2 citations
TL;DR: A large number of studies have been performed over the last two decades to assess whether electromagnetic radiations pose a potential health risk as mentioned in this paper, and the main purpose of this survey is to measure the intensity of electromagnetic radiation present in the city of Mumbai.
Abstract: A large number of studies have been performed over the last two decades to assess whether electromagnetic radiations pose a potential health risk. Worldwide researchers are working to find the correlation that exists between exposure to electromagnetic radiation and health problems. The main purpose of this survey is to measure the intensity of electromagnetic radiation present in the city of Mumbai. The findings of this survey are to facilitate responsible, fact-based decisions about the RF environment surrounding one's community, vicinity, home, or school. Few guidelines are proposed based on the findings.
2 citations
TL;DR: Four novel techniques for analog multiplication using operational amplifiers are proposed and it is shown that by employing precision sources for the reference voltages, one can achieve an acceptable level of accuracy.
Abstract: The following novel techniques for analog multiplication using operational amplifiers are proposed in this paper. (1) Sigma delta multiplier, (2) sigma integrated multiplier, (3) sigma single slope multiplier, and (4) sigma sampled multiplier. In all the above four techniques, the constant of multiplication is dependent upon two reference voltages. Employing precision sources for the reference voltages, one can achieve an acceptable level of accuracy. Verification of the feasibility of the circuit configurations are established by way of test results on a proto type.
2 citations
TL;DR: The software developed as a teaching tool conclusively proves that the original problem of calculating the number of paths from a point (0, 0) to any point (n, n) on a graph might be better understood.
Abstract: This paper is based on a supplemental instruction technique aimed at disseminating a difficult concept at the undergraduate level. The software developed as a teaching tool attacks the problem from an intuitive perspective with the aid of visual tools. The tool, run as an experiment, conclusively proves that the original problem of calculating the number of paths from a point (0, 0) to any point (n, n) on a graph might be better understood. The moves can only be east and north in whole number increments and cannot exceed the x = y line at any point. A program is written to produce the graph. Incrementing the value of (n, n), the Catalan number series is produced. Another program is written using the formula which produces the Catalan numbers, and the growth of the series is determined. The teaching tool is created based on the algorithm. A robot is designed which follows the Catalan path is also demonstrated. A survey conducted using this teaching tool shows that it enhances the learning and under...
TL;DR: In this article, two classes of networks whose Thevenin equivalent resistances are interesting are presented, and a method which not only leads the correct value instead of such indeterminate forms but also is efficient, is proposed.
Abstract: This paper presents two classes of networks whose Thevenin equivalents are interesting. One class of networks is without any independent source. The other class has loop or node method-based delta 0. If proper care is not taken, then their Thevenin equivalent resistances may result in indeterminate forms. A method, which not only leads the correct value instead of such indeterminate forms but also is efficient, is proposed. It is illustrated with two examples.