The Boundary Value Approach is used to obtain the steadystate analysis and digital simulation of voltage-controlled a.c. motor drives such as a capacitor-run single-phase induction motor with a pair of thyristors in the main winding and a 3-phase wyeconnected induction motor with a pair of thyristors in each phase.The steady-state solution is obtained without changing the elements and the rank of the matrix differential equation defining the motor for all modes of operation. In addition no iteration is required to get the steady-state initial vectors. Computed results include the predicted stator currents, voltages and the developed electro-magnetic torque and there is good qualitative and quantitative agreement with the earlier published results. NOMENCLATURE List of Symbols ids' i qs i dr, i qr irs' i y s' N a , N m

No abstract

Personal signatures are easily forged because their verification is usually limited to a visual image comparison. This paper presents a dynamic signature verification system. The system analyzes signatures dynamically by considering their shape, time domain characteristics, such as speed and acceleration, and force domain characteristics, i.e. applied pressure. Then it compares these parameters with those of previously obtained master signatures. The results are converted into a percentage match figure to determine whether the signature is qualified as authentic or forgery. Expierimental results show 92% authentic signature detection accuracy and 100% forgery signature detection accuracy. This high level of accuracy plus low computation requirements for analysis, make this system a commercially viable solution to the signature identification problem.

No abstract

As a mean for non-intrusive inspection of bearing systems, the scope of predicting their condition from the acoustic vibrations liberated during their operation, utilizing signal processing methods, has been of extensive research, over decades. Vibration being highly non-stationary, time domain as well as spectral features cannot characterize its behavior. Even though spectrogram is a time-frequency domain feature extraction technique, its interpretation is tedious and perhaps, subjective. In the proposed method, the spectrogram images of the normal vibration data is compared with that of the contextual vibration, using Structural Similarity Index Metric (SSIM). It is hypothesized that the pattern similarity between the contextual spectrogram and the baseline is low when the bearing is faulty. The SSIM between the spectrogram image of normal bearing vibration data and the baseline is different from those between the baseline and vibration data corresponding to Inner Race Failure (IRF), Roller Element Defect (RED) and Outer Race Failure (ORF). Via the proposed method of spectrogram pattern matching based on SSIM, the subjectivity in the comparative interpretation of spectrogram is eliminated fully. The SSIM corresponding to the vibrations acquired from the normal and faulty bearings differ with a P value of 4.43693x 10-16. The technique can distinguish defective bearings with, 95.74% sensitivity, 96% accuracy and 100% specificity, without dismantling or open intervention

No abstract

Peanuts have been in existence since the beginning of human life. It has a high carbon content and is rich in oil and protein. Peanut oil extraction is more common in most developing countries. Peanut is a commonly used, edible commodity, and oil is used as a cooking medium. Upon oil extraction, the by-product of the peanut cake often contains 43-65 per cent protein and 6-20 per cent fat, which is usually used as feed for cows and goats. There is currently a shortage of farm workers and an increase in harvesting costs. The factors mentioned above mean that farmers are not interested in growing peanuts. The removal of peanut shells is a time-consuming and costly operation. During harvesting, the temperature is very high, making it impossible for humans to work. Peanut thresher is used to solve these problems by removing peanuts that minimize time and expense. Our project focuses mainly on the design and development of a peanut cutting machine with a 0.5 hp motor. The workers removed the peanut capsules from the harvest at the beginning. The output of this method was very poor and did not meet consumer demand because it was a time-consuming operation. The main part of our project is a rotating drum with nails. They feed the peanuts to the rotating drum. Rotating drum tips isolate the pods from field harvest. There are large peanut harvesters on the market, but small farmers cannot afford these harvesters. Our machine is small, light and inexpensive. Farmers with a small farm may afford to use our machine.

No abstract