Displaying publications 61 - 80 of 191 in total

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  1. Suhaila Abdul Halim, Arsmah Ibrahim, Yupiter Harangan Prasada Manurung
    Scientific Research Journal, 2012;9(1):15-27.
    MyJurnal
    Accurate inspection of welded materials is important in relation to achieve acceptable standards. Radiography, a non-destructive test method, is commonly used to evaluate the internal condition of a material with respect to defect detection. The presence of noise in low resolution of radiographic images significantly complicates analysis; therefore attaining higher quality radiographic images makes defect detection more readily achievable. This paper presents a study pertaining to the quality enhancement of radiographic images with respect to different types of defects. A series of digital radiographic weld flaw images were smoothed using multiple smoothing techniques to remove inherent noise followed by top and bottom hat morphological transformations. Image quality was evaluated quantitatively with respect to SNR, PSNR and MAE. The results indicate that smoothing enhances the quality of radiographic images, thereby promoting defect detection with the respect to original radiographic images.
    Matched MeSH terms: Noise
  2. Yakno M, Mohamad-Saleh J, Ibrahim MZ
    Sensors (Basel), 2021 Sep 27;21(19).
    PMID: 34640769 DOI: 10.3390/s21196445
    Enhancement of captured hand vein images is essential for a number of purposes, such as accurate biometric identification and ease of medical intravenous access. This paper presents an improved hand vein image enhancement technique based on weighted average fusion of contrast limited adaptive histogram equalization (CLAHE) and fuzzy adaptive gamma (FAG). The proposed technique is applied using three stages. Firstly, grey level intensities with CLAHE are locally applied to image pixels for contrast enhancement. Secondly, the grey level intensities are then globally transformed into membership planes and modified with FAG operator for the same purposes. Finally, the resultant images from CLAHE and FAG are fused using improved weighted averaging methods for clearer vein patterns. Then, matched filter with first-order derivative Gaussian (MF-FODG) is employed to segment vein patterns. The proposed technique was tested on self-acquired dorsal hand vein images as well as images from the SUAS databases. The performance of the proposed technique is compared with various other image enhancement techniques based on mean square error (MSE), peak signal-to-noise ratio (PSNR), and structural similarity index measurement (SSIM). The proposed enhancement technique's impact on the segmentation process has also been evaluated using sensitivity, accuracy, and dice coefficient. The experimental results show that the proposed enhancement technique can significantly enhance the hand vein patterns and improve the detection of dorsal hand veins.
    Matched MeSH terms: Signal-To-Noise Ratio
  3. Sembulingam K, Sembulingam P, Namasivayam A
    Indian J Med Sci, 2003 Nov;57(11):487-92.
    PMID: 14646156
    Effect of various stressor agents on the adrenergic system in brain had been studied extensively. However, reports on the effect of stress on various parameters of central cholinergic system are scanty. And very little is known about the effect of noise stress on the cholinergic system in brain. Hence, it was decided to elucidate the effect of acute noise stress on the activity of the enzyme acetylcholinesterase in discrete areas of brain in albino rats. Male albino rats of Wistar strain were subjected to acute noise stress for 30 minutes. The noise of pure sine wave tone was produced by using a function generator and was amplified. The frequency of noise generated was 1 kHz and the intensity was set at 100 dB. The total acetylcholinesterase activity was determined in the tissues of cerebral cortex, corpus striatum, hypothalamus and hippocampus of brain in these rats. The enzyme activity was estimated by colorimetric method using acetylthiocholine iodide as the substrate. The values were compared with the enzyme activity in the control rats. The activity of the enzyme increased significantly in all the four regions of the brain in rats after exposure to noise stress for 30 minutes. The results of the study indicate that the exposure to acute noise stress could modulate the cholinergic system in these areas of brain in rat.
    Matched MeSH terms: Noise/adverse effects*
  4. Harun HH, Karim MKA, Abbas Z, Sabarudin A, Muniandy SC, Ibahim MJ
    J Xray Sci Technol, 2020;28(5):893-903.
    PMID: 32741801 DOI: 10.3233/XST-200699
    PURPOSE: To evaluate the influence of iterative reconstruction (IR) levels on Computed Tomography (CT) image quality and to establish Figure of Merit (FOM) value for CT Pulmonary Angiography (CTPA) examinations.

    METHODS: Images of 31 adult patients who underwent CTPA examinations in our institution from March to April 2019 were retrospectively collected. Other data, such as scanning parameters, radiation dose and body habitus information from the subjects were also recorded. Six different levels of IR were applied to the volume data of the subjects. Five circles of the region of interest (ROI) were drawn in five different arteries namely, pulmonary trunk, right pulmonary artery, left pulmonary artery, ascending aorta and descending aorta. The mean Signal-to-noise ratio (SNR) was obtained, and the FOM was calculated in a fraction of the SNR2 divided by volume-weighted CT dose index (CTDIvol) and SNR2 divided by the size-specific dose estimates (SSDE).

    RESULTS: Overall, we observed that the mean value of CTDIvol and SSDE were 13.79±7.72 mGy and 17.25±8.92 mGy, respectively. Notably, SNR values significantly increase with increase of the IR level (p 

    Matched MeSH terms: Signal-To-Noise Ratio
  5. Shaffiq Said Rahmat SM, Abdul Karim MK, Che Isa IN, Abd Rahman MA, Noor NM, Hoong NK
    Comput Biol Med, 2020 08;123:103840.
    PMID: 32658782 DOI: 10.1016/j.compbiomed.2020.103840
    BACKGROUND: Unoptimized protocols, including a miscentered position, might affect the outcome of diagnostic in CT examinations. In this study, we investigate the effects of miscentering position during CT head examination on the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).

    METHOD: We simulate the CT head examination using a water phantom with a standard protocol (120 kVp/180 mAs) and a low dose protocol (100 kVp/142 mAs). The table height was adjusted to simulate miscentering by 5 cm from the isocenter, where the height was miscentered superiorly (MCS) at 109, 114, 119, and 124 cm, and miscentered inferiorly (MCI) at 99, 94, 89, and 84 cm. Seven circular regions of interest were used, with one drawn at the center, four at the peripheral area of the phantom, and two at the background area of the image.

    RESULTS: For the standard protocol, the mean CNR decreased uniformly as table height increased and significantly differed (p 

    Matched MeSH terms: Signal-To-Noise Ratio
  6. Anita, AR., Noor Hassim, I.
    MyJurnal
    Fogging activity has become one of the important methods in tackling dengue outbreaks nowadays. Despite this, it is an occupation that has known hazards namely noise and pesticides which can affect the body organs. Based on this knowledge, a cross sectional study was conducted to determine the association between hearing impairment and serum cholinesterase level among foggers from five randomly selected Health District Offices in Selangor. A total of 200 workers comprising of 100 workers exposed to fogging activity and another 100 workers not exposed were randomly selected for this study. Data was obtained through self administered questionnaire, audiometric testing and serum cholinesterase level measurement. The overall prevalence of hearing impairment was 16% with foggers having significant higher prevalence (24%) compared to the non foggers (8%) (χ2=9.52, p=0.002). Measurement of serum cholinesterase showed that exposed workers had lower level compared to the non exposed group. Similarly, those who have hearing impairment had also lower serum cholinesterase level although it was not statistically different. Among all studied factors, age and duration of exposure to fogging activities were statistically different with hearing impairment (p
    Matched MeSH terms: Noise
  7. Abdul Rahim KA, Jewaratnam J, Che Hassan CR, Hamid MD
    PMID: 33142732 DOI: 10.3390/ijerph17218032
    Occupational noise-induced hearing loss (ONIHL) is the most reported occupational disease in Malaysia. ONIHL is aggravated by the presence of early hearing loss amongst the youth prior to entering a real working environment. At technical and vocational education training (TVET) institutions, students may develop early ONIHL because training workshops are designed imitating the industrial working environment to produce skilled workers. The exceeding noise level at workshops and recent risk of non-occupational noise can cause early ONIHL among these students. Therefore, ONIHL must be addressed at the early stage of producing skilled workers. Octa hearing conservation index (OHCI) system is developed as a management and monitoring tool for hearing conservation program (HCP) in TVET institutions. Six existing and two new HCP components were used to build the index system. A pilot test on the effectiveness of the OHCI system was conducted in a selected TVET institution for six months. The post-HCP shows a 52.6% improvement compared to the pre-HCP. The implementation of HCP has shown improved awareness on the hazards of loud noise exposure and active use of hearing protection devices among participants. The OHCI system has a great potential as a tool to improve HCP implementation in TVET institutions, and eventually, industry.
    Matched MeSH terms: Hearing Loss, Noise-Induced
  8. Ismail, N., Bashah, F. A. A., Zakaria, F.
    MyJurnal
    Many recent studies focused on the patient’s safety from the administration of gadolinium-based contrast agents (GBCAs), their concentration, the dose of administration and their effects on the image quality. The present study was aimed at evaluating the effects of reduced GBCAs (gadobutrol and gadoterate meglumine) volume on the image quality by using phantoms. Eight (8) human brain mimicking phantom made of nickel chloride (NiCl2) doped agarose gel were added with 0.00500 ml (100% volume), 0.00350 ml (75% volume), 0.00250 ml (50% volume) and 0.00125 ml (25% volume) of gadobutrol, 0.0100 ml (100% volume), 0.0075 ml (75% volume), 0.0050 ml (50% volume) and 0.0025 ml (25% volume) of gadoterate meglumine. The phantoms were scanned using a 1.5-T and a 3 T-MRI system. Signal-to-noise ratio (SNR) and the contrast agents enhancement were evaluated quantitatively and qualitatively. The 50% volume of gadobutrol and gadoterate meglumine at 3 T showed greater enhancement when compared with 50% and 100% volumes of gadobutrol and gadoterate meglumine at 1.5 T. It can be concluded that the volume of gadobutrol and gadoterate meglumine contrast agents can be reduced when using a higher field system
    Matched MeSH terms: Signal-To-Noise Ratio
  9. Salina H, Abdullah A, Mukari SZ, Azmi MT
    Eur Arch Otorhinolaryngol, 2010 Apr;267(4):495-9.
    PMID: 19727788 DOI: 10.1007/s00405-009-1080-y
    Transient-evoked otoacoustic emission (TEOAE) is a well-established screening tool for universal newborn hearing screening. The aims of this study are to measure the effects of background noise on recording of TEOAE and the duration required to complete the test at various noise levels. This study is a prospective study from June 2006 until May 2007. The study population were newborns from postnatal wards who were delivered at term pregnancy. Newborns who were more than 8-h old and passed a hearing screening testing using screening auditory brainstem response (SABRe) were further tested with TEOAE in four different test environments [isolation room in the ward during non-peak hour (E1), isolation room in the ward during peak hour (E2), maternal bedside in the ward during non-peak hour (E3) and maternal bedside in the ward during peak hour (E4)]. This study showed that test environment significantly influenced the time required to complete testing in both ears with F [534.23] = 0.945; P < 0.001 on the right ear and F [636.54] = 0.954; P < 0.001 on the left. Our study revealed that TEOAE testing was efficient in defining the presence of normal hearing in our postnatal wards at maternal bedside during non-peak hour with a specificity of 96.8%. Our study concludes that background noise levels for acceptable and accurate TEOAE recording in newborns should not exceed 65 dB A. In addition, when using TEOAE assessment in noisy environments, the time taken to obtain accurate results will greatly increase.
    Matched MeSH terms: Noise*
  10. Noor Hassim I
    Family Physician, 1991;3:14-16.
    Matched MeSH terms: Noise
  11. Othman E, Yusoff AN, Mohamad M, Abdul Manan H, Abd Hamid AI, Giampietro V
    Exp Brain Res, 2020 Apr;238(4):945-956.
    PMID: 32179941 DOI: 10.1007/s00221-020-05765-3
    The present study examined the impact of white noise on word recall performance and brain activity in 40 healthy adolescents, split in two groups (normal and low) depending on their auditory working memory capacity (AWMC). Using functional magnetic resonance imaging, participants performed a backward recall task under four different signal-to-noise ratio (SNR) conditions: 15, 10, 5, and 0-dB SNR. Behaviorally, normal AWMC individuals scored significantly higher than low AWMC individuals across noise levels. Whole-brain analyses showed brain activation not to be statistically different between groups across noise levels. In the normal group, a significant positive relationship was found between performance and number of activated voxels in the right superior frontal gyrus. In the low group, significant positive correlations were found between performance and number of activated voxels in left superior frontal gyrus, left inferior frontal gyrus, and left anterior cingulate cortex. These findings suggest that the strategic structure involved in the enhancement of AWM performance may differ in normal and low AWMC individuals.
    Matched MeSH terms: Noise
  12. Manivasagam, Dayanath
    MyJurnal
    The Department of Occupational Safety and Health Malaysia (DOSH) is the authority responsible to safeguard the occupational safety, health and welfare of workers in Malaysia. Occupational noise-related hearing disorders are the leading type of occupational diseases recorded by DOSH every year. Occupational Health Doctor (OHD) is a competency recognized by DOSH and their scope of duties in industries is currently confined to conduct medical surveillance for workers with hazardous chemical exposure and confined space medical fitness examination. The duties of OHD are good to be expanded by empowering more of their roles in industrial activities involving other legislations under DOSH. The noise exposure regulation under the Factories and Machinery Act (FMA) 1967 has been governing the worker’s exposure to hazardous industrial noise and preventing noise-induced hearing loss (NIHL) since 1989. However, the provisions of the regulation need to be strengthened in some essential medical elements of the Hearing Conservation Programme (HCP) for a comprehensive prevention of NIHL at the workplace. Recently enacted Occupational Safety and Health (Noise Exposure) Regulations 2019 offer a wider coverage of workers in ten sectors of industries applicable under the Occupational Safety and Health Act (OSHA) 1994. The current regulatory requirements for management of workplace noise have many improvements compared to the existing law. Enhancement in the medical requirements of industrial audiometry is made prominent by involving OHDs to interpret audiograms and conduct medical examination for workers. The reporting of occupational noise-related hearing disorders to DOSH is outlined better in the new regulation. The occurrence of NIHL and other related hearing disorders are expected to reduce eventually after the introduction of Occupational Safety and Health (Noise Exposure) Regulations 2019. The OHDs will play a pivotal role in industrial audiometry and prevention of hearing disorders among the working population.
    Matched MeSH terms: Hearing Loss, Noise-Induced; Noise, Occupational
  13. Lee, K.Y., Ho, L.Y., Tan, K.H., Tham, Y.Y., Ling, S.P., Qureshi, A.M., et al.
    MyJurnal
    In the perspective of recent bauxite mining in Malaysia, this review aims to identify the potential
    environmental and health impacts on miners and surrounding communities. The environmental issues of
    bauxite mining include, air, water and soil pollution due to bauxite dust; leaching of bauxite into water
    sources resulting in reduced soil fertility as well as affecting agricultural food products and aquatic life.
    Bauxite occupational exposure affects the health of miners, and has negative consequences on the health of
    surrounding communities, such as increased respiratory symptoms, contamination of drinking water, other
    potential health risks from ingestion of bauxite and heavy metals, including noise-induced hearing loss and
    mental stress. This review discusses the processes of bauxite mining, its constituents and residual trace
    elements, and their impact on the environment and health of exposed workers and communities. It also
    explores the Malaysian legal requirements and standards of occupational exposure to bauxite.
    Matched MeSH terms: Hearing Loss, Noise-Induced
  14. Muhd-Yassin, S.Z., Harun, S.W., Ahmad, H., Abd-Rahman, M.K.
    ASM Science Journal, 2008;2(2):163-168.
    MyJurnal
    An efficient erbium/ytterbium co-doped fibre amplifier was demonstrated by using a dual-stage partial doublepass structure with a band-pass filter (BPF). The amplifier achieved the maximum small signal gain of 56 dB and the corresponding noise figure of 4.66 dB at 1536 nm with an input signal power and total pump power of –50 dBm and 140 mW, respectively. Compared with a conventional single-stage amplifier, the maximum gain enhancement of 16.99 dB was obtained at 1544 nm with the corresponding noise figure was improved by 2 dB. The proposed amplifier structure only used a single pump source with a partial double pass scheme to provide a high gain and dual-stage structure to provide the low noise figure.
    Matched MeSH terms: Noise
  15. Sen RN, Yeow PH
    Int J Occup Saf Ergon, 2003;9(1):57-74.
    PMID: 12636892
    The study aimed at reducing the occupational health and safety problems faced by the manual component insertion operators. Subjective and objective assessments, and direct observations were made in the printed circuit assembly factory. Simple and low-cost ergonomic interventions were implemented, that is, repairing chairs, reducing high workloads, assigning operators to a maximum of 2 workstations, confining machines that emitted bad smell and much noise, and providing finger work aids. The results of the interventions were reductions in operators' work discomforts, that is, chair discomfort (by 90%), high work stress, and discomfort due to profound change in their workstations. Their health hazards were also eliminated, that is, inhalation of toxic fumes, exposure to too much noise, and pain due to pressing sharp components.
    Matched MeSH terms: Noise, Occupational
  16. Abdullah KA, McEntee MF, Reed W, Kench PL
    J Med Radiat Sci, 2020 Sep;67(3):170-176.
    PMID: 32219989 DOI: 10.1002/jmrs.387
    INTRODUCTION: 3D-printed imaging phantoms are now increasingly available and used for computed tomography (CT) dose optimisation study and image quality analysis. The aim of this study was to evaluate the integrated 3D-printed cardiac insert phantom when evaluating iterative reconstruction (IR) algorithm in coronary CT angiography (CCTA) protocols.

    METHODS: The 3D-printed cardiac insert phantom was positioned into a chest phantom and scanned with a 16-slice CT scanner. Acquisitions were performed with CCTA protocols using 120 kVp at four different tube currents, 300, 200, 100 and 50 mA (protocols A, B, C and D, respectively). The image data sets were reconstructed with a filtered back projection (FBP) and three different IR algorithm strengths. The image quality metrics of image noise, signal-noise ratio (SNR) and contrast-noise ratio (CNR) were calculated for each protocol.

    RESULTS: Decrease in dose levels has significantly increased the image noise, compared to FBP of protocol A (P 

    Matched MeSH terms: Signal-To-Noise Ratio
  17. Sulaiman AH, Husain R, Seluakumaran K
    Eur Arch Otorhinolaryngol, 2014 Jun;271(6):1463-70.
    PMID: 23812554 DOI: 10.1007/s00405-013-2612-z
    Although sound exposure from personal listening devices (PLDs) could potentially lead to noise-induced hearing loss (NIHL), the actual hearing risk associated with the use of these devices is still unclear. In this study, early hearing effects related to PLD usage were evaluated in 35 young adult PLD users (listening for >1 h/day, at >50% of the maximum volume setting of their devices) and their age- and sex-matched controls using a combination of conventional and extended high-frequency audiometry as well as transient-evoked otoacoustic emission (TEOAE) and distortion product of otoacoustic emission (DPOAE) measurements. The mean listening duration of the PLD users was 2.7 ± 1.0 h/day while their estimated average listening volume was 81.3 ± 9.0 dBA (free-field corrected). Typical signs of NIHL were not detected in the audiogram of PLD users and their audiometric thresholds at most of the conventional test frequencies (0.25-8 kHz) were comparable with those obtained from controls. However, compared with the controls, mean hearing thresholds of PLD users at many of the extended high-frequencies (9-16 kHz) were significantly higher. In addition, TEOAE and DPOAE amplitudes in users were reduced compared with controls. The deterioration of extended high-frequency thresholds and the decrease in DPOAE amplitudes were more evident in the users' right ears. These results indicate the presence of an early stage of hearing damage in the PLD user group. Preventive steps should be taken as the initial hearing damage in these users could eventually progress into permanent NIHL after many years of PLD use.
    Matched MeSH terms: Hearing Loss, Noise-Induced/diagnosis*
  18. Quar TK, Ching TY, Newall P, Sharma M
    Int J Audiol, 2013 May;52(5):322-32.
    PMID: 23570290 DOI: 10.3109/14992027.2012.755740
    The study aims to compare the performance of hearing aids fitted according to the NAL-NL1 and DSL v5 prescriptive procedure for children.
    Matched MeSH terms: Noise/adverse effects
  19. Dinesh, S., Faudzi, M.M., Rafidah, M., Shakhira, B.N.I., Robiah, A.S., Shalini, S.S., et al.
    ASM Science Journal, 2014;8(1):11-20.
    MyJurnal
    In this study, Global Positioning System (GPS) simulation was employed to study the effect of radio frequency interference (RFI) on two hand-held GPS receivers; Garmin GPSmap 60CSx (evaluated GPS receiver) and Garmin GPSmap 60CS (reference GPS receiver). Both GPS receivers employed the GPS L1 coarse acquisition (C/A) signal. It was observed that the interference signal power levels required to affect the location fixes of the GPS receivers were significantly high compared to the corresponding GPS signal power levels. The noiselike C/A code structure, which modulated the L1 signal over a 2 MHz bandwidth, allowed for the signal to be received at low levels of interferences. The evaluated GPS receiver had better RFI operability as compared to the reference GPS receiver. This is because the evaluated GPS receiver had higher receiver sensitivity, allowing it to have increased carrier-to-noise density (C/N0) levels for GPS satellites tracked by the receiver. The absence of other error parameters, including ionospheric and tropospheric delays, satellite clock, ephemeris and multipath errors, and unintentional signal interferences and obstructions, resulted in the required minimum jamming power levels in this study to be significantly higher as compared to field evaluations. These minimum jamming power levels vary with location and time. This was due to the GPS satellite constellation being dynamic, causing varying GPS satellite geometry over location and time, resulting in the minimum required GPS jamming power levels being location / time dependent. In general, the lowest minimum jamming power levels were observed for readings with the highest position dilution of precision (PDOP) values, and vice versa.
    Matched MeSH terms: Noise
  20. Masoud F, Sapuan SM, Ariffin MKAM, Nukman Y, Bayraktar E
    Polymers (Basel), 2021 Feb 26;13(5).
    PMID: 33652612 DOI: 10.3390/polym13050706
    In this paper, the influence of processing input parameters on the heat-affected zone (HAZ) of three different material thicknesses of sugar palm fiber reinforced unsaturated polyester (SPF-UPE) composites cut with a CO2 laser was investigated. Laser power, traverse speed, and gas pressure were selected as the most influential input parameters on the HAZ to optimize the HAZ response with fixing all of the other input parameters. Taguchi's method was used to determine the levels of parameters that give the best response to the HAZ. The significance of input parameters was also determined by calculating the max-min variance of the average of the signal-to-noise ratio (S/N) ratio for each parameter. Analysis of variation (ANOVA) was used to determine each input parameter's contribution to the influence on HAZ depth. The general results show that the minimum levels of laser power and the highest levels of traverse speed and gas pressure gave the optimum response to the HAZ. Gas pressure had the most significant effect on the HAZ, with contribution decreases as the material thickness increased, followed by the traverse speed with contribution increases with the increase in material thickness. Laser power came third, with a minimal contribution to the effect on the HAZ, and it did not show a clear relationship with the change in material thickness. By applying the optimum parameters, the desired HAZ depth could be obtained at relatively low values.
    Matched MeSH terms: Signal-To-Noise Ratio
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