pp 637-655 December 2012
In this paper, a novel approach to reduce the effect of mode coupling that causes friction induced vibration (FIV) is proposed by applying an intelligent active force control (AFC)-based strategy employing piezoelectric actuators with hysteresis effect to a simpliﬁed two degree-of-freedom mathematical model of a friction-induced vibration system. At ﬁrst, the model is simulated and analysed using a closed loop pure Proportional-Integral-Derivative (PID) controller. Later, it is integrated with the intelligent AFC with fuzzy logic (FL) estimator and simulated under similar operating condition. After running several tests with different sets of operating and loading conditions, the results both in time and frequency domains show that the PID controller with the intelligent AFC is much more effective in reducing the vibration, compared to the pure PID controller alone.
pp 657-664 December 2012
The performance of multilayers has been widely investigated in metal/metal systems. Shrinking this system down to less than 10 nm dislocation blocking occurs. We should thus try to ﬁnd a way to get a structure with less dislocation, and/or strain because low diffusivity ultra high vacuum chamber is the basic requirements for growing ultra thin ﬁlms and nano scale materials. We used William–Hall relation based on Scherr equation in X-ray powder spectrum and drawn the stress–strain diagrams. It shows that Al–Fe–Cr–Ti composites have very low diffusivity and equilibrium solubility in Al (0.05 at.% Fe, >0.02 at.% Cr, and >0.3 at.% Ti). Al–Ti– Fe–Cr composite powders have also been prepared from sol–gel method starting from elemental powders at both ambient and elevated temperatures. The obtained results from XRD (X-ray Diffraction), AFM (Atomic Force Microscopy) and X-ray powder techniques indicate that nano-grains with 0.03 at %Cr can cause a reduction of leakage current through the SS chamber due to its amorphous structure.
pp 665-674 December 2012
The minimum cost ﬂow problem with interval data can be solved using two minimum cost ﬂow problems with crisp data. In this paper, the idea of Ghiyasvand was extended for solving the minimum ﬂow problem with interval-valued lower, upper bounds and ﬂows. This problem can be solved using two minimum ﬂow problems with crisp data. Then, this result is extended to networks with fuzzy lower, upper bounds and ﬂows.
pp 675-694 December 2012
Parallel and distributed systems play an important part in the improvement of high performance computing. In these type of systems task scheduling is a key issue in achieving high performance of the system. In general, task scheduling problems have been shown to be NP-hard. As deterministic techniques consume much time in solving the problem, several heuristic methods are attempted in obtaining optimal solutions. This paper presents an application of Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) and a Non-dominated Sorting Particle Swarm Optimization Algorithm (NSPSO) to schedule independent tasks in a distributed system comprising of heterogeneous processors. The problem is formulated as a multi-objective optimization problem, aiming to obtain schedules achieving minimum makespan and ﬂowtime. The applied algorithms generate Pareto set of global optimal solutions for the considered multi-objective scheduling problem. The algorithms are validated against a set of benchmark instances and the performance of the algorithms evaluated using standard metrics. Experimental results and performance measures infer that NSGA-II produces quality schedules compared to NSPSO.
pp 695-707 December 2012
This paper explains minimization of makespan or total completion time for 𝑛-jobs, 𝑚-machine, no-wait ﬂowshop problem (NW-FSSP). A spread sheet based general purpose genetic algorithm is proposed for the NW-FSSP. The example analysis shows that the proposed approach produces results are comparable to the previous approaches cited in the literature. Additionally, it is demonstrated that the current application is a general purpose approach whereby the objective function can be tailored without any change in the logic of the GA routine.
pp 709-721 December 2012
In this paper, an efﬁcient similarity measure technique is proposed for medical image registration. The proposed approach is based on the Gerschgorin circles theorem. In this approach, image registration is carried out by considering Gerschgorin bounds of a covariance matrix of two compared images with normalized energy. The beauty of this approach is that there is no need to calculate image features like eigenvalues and eigenvectors. This technique is superior to other well-known techniques such as normalized cross-correlation method and eigenvalue-based similarity measures since it avoids the false registration and requires less computation. The proposed approach is sensitive to small defects and robust to change in illuminations and noise. Experimental results on various synthetic medical images have shown the effectiveness of the proposed technique for detecting and locating the disease in the complicated medical images.
pp 723-729 December 2012
In this paper, we propose a method for watermarking medical images for data integrity which consists of image encryption, data embedding and image-recovery phases. Data embedding can be completely recovered from the watermarked image after the watermark has been extracted. In the proposed method, we utilize standard stream cipher for image encryption and selecting non-region of interest tile to embed patient data. We show that the lower bound of the PSNR (peak-signal-to-noise-ratio) values for medical images is about 48 dB. Experimental results demonstrate that the proposed scheme can embed a large amount of data while keeping high visual quality of test images.
pp 731-737 December 2012
Ordinary Portland cement (OPC) samples containing the chromium salt have been investigated using differential microcalorimetry, conductometry and Fourier transform infrared spectroscopic analysis. The effect of chromium on OPC hydration was evaluated by continuous observing of early hydration. The microcalorimetrical results show that with increasing the share of chromium salt, heat maximums assume lower values and the occurrence of the maximum registered in the earlier hydration times. Conductometrical measurements show that with increasing addition of chromium salt, curve did not show any speciﬁc shape, immediate drop in speciﬁc conductivity is noticed and the maximum is reached earlier. This coincides with microcalorimetrical results. It can be concluded that the addition of chromium does not affect the mechanism of the hydration process, but it does affect the kinetic parameters and dynamics of the cement hydration process. It was found that chromium salt addition to the cement–water system is acceptable up to 2 wt.%. According to standard EN 196-3 for OPC, the beginning of binding time should occur after 60 minutes. Increased amount of chromium over 2 wt.% signiﬁcantly accelerate the beginning of binding time and for the system it is not acceptable.
pp 739-745 December 2012
We propose a scheme for automating power law transformations which are used for image enhancement. The scheme we propose does not require the user to choose the exponent in the power law transformation. This method works well for images having poor contrast, especially to those images in which the peaks corresponding to the background and the foreground are not widely separated.
pp 747-761 December 2012
Speech is one of the most important communication channels among the people. Speech Recognition occupies a prominent place in communication between the humans and machine. Several factors affect the accuracy of the speech recognition system. Much effort was involved to increase the accuracy of the speech recognition system, still erroneous output is generating in current speech recognition systems. Telugu language is one of the most widely spoken south Indian languages. In the proposed Telugu speech recognition system, errors obtained from decoder are analysed to improve the performance of the speech recognition system. Static pronunciation dictionary plays a key role in the speech recognition accuracy. Modiﬁcation should be performed in the dictionary, which is used in the decoder of the speech recognition system. This modiﬁcation reduces the number of the confusion pairs which improves the performance of the speech recognition system. Language model scores are also varied with this modiﬁcation. Hit rate is considerably increased during this modiﬁcation and false alarms have been changing during the modiﬁcation of the pronunciation dictionary. Variations are observed in different error measures such as F-measures, error-rate and Word Error Rate (WER) by application of the proposed method.
pp 763-766 December 2012
pp 767-775 December 2012