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PublicationAnalysis of wheeze sounds during tidal breathing according to severity levels in asthma patients(Taylor & Francis, 2019)Objective: This study aimed to statistically analyze the behavior of time-frequency features in digital recordings of wheeze sounds obtained from patients with various levels of asthma severity (mild, moderate, and severe), and this analysis was based on the auscultation location and/or breath phase. Method: Segmented and validated wheeze sounds were collected from the trachea and lower lung base (LLB) of 55 asthmatic patients during tidal breathing maneuvers and grouped into nine different datasets. The quartile frequencies F25, F50, F75, F90 and F99, mean frequency (MF) and average power (AP) were computed as features, and a univariate statistical analysis was then performed to analyze the behavior of the time-frequency features. Results: All features generally showed statistical significance in most of the datasets for all severity levels [χ2 = 6.021–71.65, p < 0.05, η2 = 0.01–0.52]. Of the seven investigated features, only AP showed statistical significance in all the datasets. F25, F75, F90 and F99 exhibited statistical significance in at least six datasets [χ2 = 4.852–65.63, p < 0.05, η2 = 0.01–0.52], and F25, F50 and MF showed statistical significance with a large η2 in all trachea-related datasets [χ2 = 13.54–55.32, p < 0.05, η2 = 0.13–0.33]. Conclusion: The results obtained for the time-frequency features revealed that (1) the asthma severity levels of patients can be identified through a set of selected features with tidal breathing, (2) tracheal wheeze sounds are more sensitive and specific predictors of severity levels and (3) inspiratory and expiratory wheeze sounds are almost equally informative.
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PublicationArtificial neural network application in an implemented lightning locating system(Elsevier, 2020)Time difference of arrival (TDOA) technique is one of many bases to determine lightning strike location employed in a lightning locating system (LLS). In this technique, at least four measurement sensors are required to correctly locate a lightning strike. Usage of fewer number of sensors will result in non-unique solutions to the generated hyperbolas, and hence wrong lightning strike point. This research aims to correctly determine the strike point even if only three measuring sensors are utilized. An artificial neural network (ANN) based algorithm was developed for a 400 km2 coverage area in Southern Malaysia using time of arrival data collected at the three measuring stations over a certain period. The Levenberg–Marquardt algorithm is demonstrated to correctly identify the lightning strike coordinates with an average error of 350 m. The algorithm has helped the three-station TDOA-based LLS to successfully locate the lightning strike point with a remarkable accuracy comparable to that of commercial systems.
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PublicationA LabVIEW-based real-time GUI for switched controlled energy harvesting circuit for low voltage application(Taylor and Francis, 2018)This paper develops a universal Real-Time Graphical User Interface for the first time for low-voltage energy Harvesting. The proposed GUI is built in LabVIEW with NIUSB 621 DAQ that synchronized the data to perform real-time analysis through the use of power electronics. A hybrid Vertical Axis Wind Turbine adapted to a 200 W Permanent Magnet Synchronous Generator is used for incorporating the supercapacitor-based battery charging energy harvesting system. The GUI displays the real-time energy harvesting output readings both graphically and digitally along with wind speed and angular velocity of the turbine. The model is built in such a way so that it could be used as a universal GUI for both wind and solar energy harvesting with minimal adjustment.
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PublicationKnowledge of Human Papillomavirus (HPV) and cervical cancer among Malaysia residents: a review(Penerbit UKM, 2020)Cervical cancer is ranks as the third leading cause of female cancer deaths among women in Malaysia. Most of the cervical cases are caused by Human Papillomavirus (HPV) infection. To prevent HPV infection, Malaysia Government had implement Human Papillomavirus (HPV) vaccination program to all secondary school girls from 13 years old and above. The focus in this paper was to review the article based on the knowledge on HPV and cervical cancer among Malaysia resident before and after the implementation of HPV vaccine program. The knowledge about HPV, HPV vaccine, and cervical cancer after the implementation of national HPV vaccination program is better compare to before the program to be implemented. However, the knowledge is still poor among the respondents although there is an improvement after the program been implemented. The respondent gives a positive attitude towards HPV vaccination and cervical cancer screening. The main barrier of vaccination and Pap smear test are side effects, risk, cost, and effectiveness. In conclusion, knowledge about HPV and cervical cancer is really important among women. Education programs to the public are needed to enhance knowledge and to control the illness.
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PublicationPrediction of surface leakage current of overhead insulators under environmental and electrical stresses(Institute of Advanced Engineering and Science (IAES), 2020)Leakage current is one of the critical aspects to consider for overhead transmission line insulator’s condition and performance assessment. As the leakage current increase, the size of the dry band also will increase leads to the dry band arcing, deteriorate the insulator performance and contribute to the development of insulator flashover. Based on the literature study, other than the existence of contaminations on the surface of insulator combined with moisture, the variation in leakage current is also affected by the environmental and electrical stresses. Previous researches have shown the effect of environmental and electrical stresses on surface leakage current based on experimental and simulation results. This paper outlines an analytical approach based on dimensional analysis to propose a new mathematical model of leakage current under environmental and electrical stresses. To justify the applicability of the derived dimensional model, the new model has been validated using previous researcher’s experimental results. The validation indicated that the proposed model had shown a good agreement with the previous experimental results. The proposed dimensional equation for this research work can be potentially used as a predictive performance model to evaluate and monitor the leakage current and insulator’s performance