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Saipullah K.M.,UniversitiTeknikal Malaysia Melaka eM | Ismail N.A.,UniversitiTeknikal Malaysia Melaka eM
2012 IEEE Asia-Pacific Conference on Applied Electromagnetics, APACE 2012 - Proceedings

Spectral classification for hyperspectral image is a challenging job because of the number of spectral in a hyperspectral image and high dimensional spectral. In this paper, we proposed a method to enhance the spectral classification using the Adaboost for hyperspectral image analysis. By applying the Adaboost algorithm to the classifier, the classification can be executed iteratively by giving weight to the spectral data, thus will reduce the classification error rate. The Adaboost is implemented to spectral angle mapper (SAM), Euclidean distance (ED), and city block distance (CD). From the experimental results, the Adaboost increases the average classification accuracy of 2000 spectral up to 99.63% using the CD. Overall, Adaboost increases the average classification accuracy of ED, CD, and SAM by 2.54%, 1.95%, and 1.67%. © 2012 IEEE. Source

Hudha K.,National Defence University of Malaysia | Jamaluddin H.,University of Technology Malaysia | Nuri N.R.B.M.,UniversitiTeknikal Malaysia Melaka eM
International Journal of Engineering Systems Modelling and Simulation

This paper investigates the performance of a magnetorheological brake (MR brake) system in terms of torque generated by various electric currents at various rotational shaft speeds. The MR brake consists of a rotating disc immersed with magnetorheological fluid (MR fluid) in an enclosure of an electromagnetic coil. The applied magnetic field will increase the yield strength of the MR fluid, which will decrease the speed of the rotating shaft. Then, different speeds were applied to the MR brake system continuously by changing the applied electric current. The methodology begins with the design using 3D modelling software followed by the development of a mathematical model of the MR brake. Then, magnetostatic analysis using ANSYS software was done by considering three parameters, which are magnetic field intensity, magnetic flux density and 2D flux lines. The torque response of the MR brake from the simulation was validated with experimental results and discussed. It can be noted that the MR brake torque increases proportionally with the increase in current and independent with varying speeds. Copyright © 2014 Inderscience Enterprises Ltd. Source

Omar R.,UniversitiTeknikal Malaysia Melaka eM | Sulaiman M.,UniversitiTeknikal Malaysia Melaka eM
International Journal of Applied Engineering Research

Multilevel inverter using cascaded H-bridge inverter with separated dc source (SDCSs) are introduced in single phase structure. The output voltage is the sum of the output of each H-bridge cell. The output voltage waveform is ideal with suitable switching angle estimation to produce required fundamental voltage. This paper presents the simulation of 5-level cascaded H-bridge multilevel inverter with selecting different switching angle based on Newton-Raphson method is used for angle optimization. Simulation work is done by using MATLAB/Simulink software. © Research India Publications. Source

Azam M.A.,UniversitiTeknikal Malaysia Melaka eM | Dorah N.,UniversitiTeknikal Malaysia Melaka eM | Seman R.N.A.R.,UniversitiTeknikal Malaysia Melaka eM | Manaf N.S.A.,UniversitiTeknikal Malaysia Melaka eM | Kudin T.I.T.,University Technology of MARA
Materials Technology

A conventional but simple fabrication technique of activated carbon/graphene (AC/G) supercapacitor electrode will be presented in this work. The AC/G electrode was prepared using slurry technique from the mixture of AC and graphene powders, polytetrafluoroethylene as binder and N-methylpyrrolidone as solvent. The AC/G electrode was dried at 120°C in vacuum oven for 6 h followed by immersing in 1M lithium hexafluorophosphate electrolyte for another 6 h. The specific gravimetric capacitance of the electrode was calculated to be 19·45 F g-1 using cyclic voltammetry at a scan rate of 1 mV s-1. Electrochemical behaviour including charge discharge and impedance characteristics confirmed the electrode's ability as a possible active material for use in carbon based supercapacitor. © 2015 W. S. Maney & Son Ltd. Source

Hadi M.H.A.,UniversitiTeknikal Malaysia Melaka eM | Ahmad B.H.,UniversitiTeknikal Malaysia Melaka eM | Shairi N.A.,UniversitiTeknikal Malaysia Melaka eM | Wen Wong P.,Petronas University of Technology
IEEE Symposium on Wireless Technology and Applications, ISWTA

This paper investigates the effect of a discrete PIN diode on Defected Ground Structure (DGS) where the different resonant frequency between ON and OFF state of the PIN diode is observed. Analytical modeling is determined and analyzed based on equivalent circuit of PIN diode and DGS. Then, a circuit simulation is performed using simulation software with different value of inductance and capacitance of DGS during ON and OFF state of the PIN diode. As a result, the resonant frequency of the PIN diode on the DGS shifted to higher frequency during ON state and shifted to lower frequency during OFF state. Besides, a larger value of inductance with a smaller value of capacitance of DGS will produce a larger range of resonant frequency between ON and OFF state and vice versa. © 2013 IEEE. Source

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