Browsing by Author "Othman M."
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Publication Characterizations of a single rod electrode under high impulse currents with different polarities(Institute of Electrical and Electronics Engineers Inc., 2017) ;Etobi A.N. ;Nor N.M. ;Abdullah S. ;Eng N.E.Othman M.Under high impulse currents, an earthing system exhibits different impulse characteristics depending on the shape and/or design configuration of the earthing system. These characteristics have been seen to be different with respect to its steady-state as highlighted in many studies. Furthermore, in order to ascertain that a correct design of an electrical system is achieved, it is important to evaluate the impulse characteristics of the earthing system under high impulse conditions. So far little emphasis has been given in previous publications to investigate the characteristics of earthing systems under high impulse conditions by field measurements. For this reason, a rather efficient and reliable technique to solve this problem is by conducting a practical analysis (field experiment). This paper investigates the characteristics of a single rod electrode under high impulse conditions by field measurements under different polarities. The single rod is selected in this paper for its simple configuration and installation. It was observed in this study that the resistance of the single rod earthing system was seen to reduce with increasing current magnitudes for both polarities and negative polarity has higher impulse resistance than that of positive polarity. � 2017 IEEE. - Some of the metrics are blocked by yourconsent settings
Publication Effect of bandpass filter bandwidth on the performance of linear cavity multiwavelength BEFL(2013) ;Mansoor A. ;Nan P.Y. ;Rashid H.A.A. ;Yusoff Z. ;Othman M. ;Faculty of Science and Technology ;Multimedia UniversityUniversiti Sains Islam Malaysia (USIM)We have investigated the self-lasing effect of the linear multiwavelength Brillouin-Erbium fiber laser with different tunable bandpass filter's bandwidth. Two 3dB bandwidth of 1 nm and 3 nm filter were used in this study. The experimental results show that the width of the TBF bandwidth plays an important role in shaping the self-lasing effect. By using the tunable bandpass filter with a broader bandwidth, the self-lasing effect can be suppressed efficiently thus producing higher Brillouin Stokes lines. At 0 dBm Brillouin pump power, up to 11 stable output laser channels can be obtained with the utilization of the 3 nm TBF as compared to only 5 output channels with the utilization of 1 nm TBF. � 2013 IEEE. - Some of the metrics are blocked by yourconsent settings
Publication The effect of total bits and number of LFSRs on the hardware performance of modified A5/1 stream ciphers(American Scientific Publishers, 2017) ;Fauzi S.Y.A.B.M. ;Othman M. ;Shuib F.M.M. ;Seman K. ;Faculty of Engineering and Built Environment ;Faculty of Science and TechnologyUniversiti Sains Islam Malaysia (USIM)This paper is a study on the hardware implementation of the modified A5/1 stream cipher used for Global System for Mobile (GSM) communication. While software simulation is one of the possible methods used to test the security of the cryptographic algorithm, one must also consider the practicality of the algorithm�s design which ultimately is to be implemented into hardware, in line with the exponential increase in the need for high speed and high performance devices. Despite the numerous work reported on the design versus security trade-off of the A5/1, to the best of the author�s knowledge, none looked at the effect of the modified design parameters, specifically the total bits and number of linear feedback shift registers (LFSRs) on the power performance of the algorithm when translated into hardware. In this work, three modified designs, with varying number of LFSRs and total bits are looked at. An increase in the number of LFSRs is observed to result in the highest power consumption, while the combination of both increased total bits and LFSRs reduced this need for power slightly. It has been found that an increase in the number of total bits alone gave the best hardware performance overall. � 2017 American Scientific Publishers All rights reserved. - Some of the metrics are blocked by yourconsent settings
Publication Influence of remote earth and impulse polarity on earthing systems by field measurement(Institution of Engineering and Technology, 2018) ;Abdullah S. ;Nor N.M. ;Agbor N. ;Reffin M. ;Othman M. ;Faculty of Engineering and Built Environment ;Multimedia UniversityUniversiti Sains Islam Malaysia (USIM)There has been a vast vacuum in the literature on the importance of the location of remote earth carried out during impulse test on grounding systems using field measurements. Some published work show that the remote earth is installed surrounding the electrode under tests, whilst some have used separate remote earth, away from it. This work studies the impact of return electrode location on transient behaviour of the earthing electrode. The electrode under test is a single rod. Two types of remote earth configurations are used, a circular electrode with multiple rods surrounding the single rod, and one that is 80 m away from it. Impulse tests are conducted under both impulse polarities. Voltage and current traces are captured for a single rod, using two different types of remote earth configurations, with the impulse resistance measured as well. It has been established that the arrangement of the remote earth poses no influence on the test results. That said, higher oscillations of current traces and higher resistance values have been observed in negative impulse in comparison with positive impulse polarities. � The Institution of Engineering and Technology 2018. - Some of the metrics are blocked by yourconsent settings
Publication Methodologies of impulse tests on earthing systems by field measurements with different remote earth(Institute of Electrical and Electronics Engineers Inc., 2016) ;Yunus S. ;Nor N.M. ;Agbor N. ;Othman M. ;Faculty of Science and Technology ;Multimedia UniversityUniversiti Sains Islam Malaysia (USIM)Nowadays, with a good design and available facilities of high impulse generators that can be taken to field sites for measurements, much research work can be found on the field measurement on the study of the grounding under fast transients. Moreover, field tests on earthing systems have become interesting since it can provide the closest scenario of the characteristics of grounding system when fast transient current discharged to the earthing systems. However, the field measurements have some limitations on the standard methodologies that should be adopted during the field measurements. There is also very little being mentioned on the arrangements/values of the remote earth. As generally known, the remote/auxillary earth is important not only for the purpose of discharging any high fault current during the tests on the electrode under tests, but also to ensure that the remote earth is not being included in the measurements, hence affect the accuracy of the measurements. Due to these factors, this paper is to aimed to study how different configurations and resistance values of remote earth on the characteristics of main earthing systems. It was found that different results were obtained when higher earth resistance values of remote earth were used for impulse tests on main earthing systems. � 2016 IEEE.