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Fulltext Temporal anticipation under cognitive stress

Suppiah, Pathmanathan K., Mohamad Razali Abdullah

Movement Health & Exercise, 2012;1(1):61-73.
MyJurnal

The ability to produce performances at highest level under physically and emotionally demanding conditions underline the worth of a sportsperson. These stressful conditions places demands on the cognitive resources of the sportsperson; especially in anticipatory actions that require the allocation of cognitive resources. This study investigated the effects of cognitive stress on the temporal anticipation of a timing motor task. A repeated measures design was applied with two independent variables; cognitive stress and levels of difficulty, which included easy, intermediate and difficult. Study participants were 18 male and 18 female undergraduates of the Physical Education programme of Universiti Putra Malaysia. The experimental task involved performing a timing motor task across the three levels of difficulty, under two conditions as follows: (i) without cognitive stress, and (ii) under cognitive stress. Cognitive stress was induced via the continuous subtraction of two from a two-digit number. Participants performed the task individually and the sequence of the experimental task was counter-balanced. A two-way within subject ANOVA was
performed to ascertain the effects of cognitive stress on the temporal anticipation of the timing motor task. Data yielded significant difference in means for the stress main effect [Λ = .64, F (1.35) = 19.89, p < 0.05]; and the task main effect [Λ = .84, F (2, 34) = 3.35, p < 0.05]. Post hoc comparisons produced a significant difference in the means of the performance of the timing motor task at all three levels of difficulty. Data showed that cognitive stress had an effect on the temporal anticipation of the timing motor task. These results are explained from attentional and the neuromotor noise perspectives. It was concluded that the significant difference in the performance of the experimental task was due to the competition for intentional resources and the decrease of the signal to noise ratio due to cognitive stress.

Matched MeSH terms: Noise; Signal-To-Noise Ratio
Evaluation of early hearing damage in personal listening device users using extended high-frequency audiometry and otoacoustic emissions

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*
Hearing risk associated with the usage of personal listening devices among urban high school students in Malaysia

Sulaiman AH, Seluakumaran K, Husain R

Public Health, 2013 Aug;127(8):710-5.
PMID: 23474376 DOI: 10.1016/j.puhe.2013.01.007

To investigate listening habits and hearing risks associated with the use of personal listening devices among urban high school students in Malaysia.

Matched MeSH terms: Hearing Loss, Noise-Induced/etiology*
Digital radiographic image enhancement for weld defect detection using smoothing and morphological transformations

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
Hearing loss in walkman users

Sofia Jaffer, Mohd Shakil Razi

Journal of Occupational Safety and Health, 2004;1(1):31-37.
MyJurnal

This retrospective study was conducted at the audiology clinic of UKM in the year 2000. It was intended to detect the effect of walkman on the hearing system of its users and to investigate whether distortion product otoacoustic emission test can provide an early and reliable sign of cochlear damage or not. Distortion product otoacoustic emission test helps to determine the function of outer hair cell. Outer hair cells get damaged with exposure to loud sound, drugs and aging. Thirty subjects (20 in the study group and 10 in the control group), between the ages of 19-25 years, who fulfilled all the criteria of selection, were investigated. There were two sets of criteria (general and specific). Anyone, in the control or study group, failing in any of these criteria was excluded from the study. According to the general criteria, it was essential for all the subjects to have clean ear canals, normal hearing at all the frequencies (250Hz- 8000Hz), normal middle ear function (Type A tympanogram), no middle ear problem, not used/using any ototoxic medicine, no family history of hearing loss, no history of ear surgery, not exposed to any form of loud noise like disco, concert, F1 racing or gun shooting. According to the special criteria it was essential for the subjects in the control group to have never used a walkman and those in the study group must have been using a walkman for at least 6 months. Comparison of distortion product emission levels between control and study groups revealed that emissions were significantly lower in the study group, across all the frequencies, suggesting outer hair cell damage in the walkman users. These differences reached level of statistical significance (p<0.05) at 2, 4, 6 and 8kHz. Using walkman at an intensity unsafe for hearing and a duration longer than recommended is suspected for the outer hair cell damage in our study group. Those using walkman for longer duration and higher intensity manifested much lower emission levels. Our study supports the literature that distortion product emission test is a much sensitive test than pure-tone audiometry, as it can detect cochlear damage long before it appears in an audiogram. It is recommended that people who are exposed to loud noise regularly should be monitored with distortion product emission test. It is suggested that the use of walkman.
Study site: Audiology clinic, Pusat Perubatan Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia

Matched MeSH terms: Noise
Fulltext Multi-frequency ultrasound imaging: phantom study

Siti Nur Masturah Abdul Malek, Sayed Inayatullah Shah

International Journal of Allied Health Sciences, 2018;2(2):304-309.
MyJurnal

In ultrasound imaging there is compromise between the penetration of signal at certain depths into the object and image resolution as the ultrasound probe only can transmit single frequency signals in one transmission. Using curvilinear ultrasound probe with 2 to 5 MHz frequency bandwidth, this study investigated the use of multi-frequency imaging to enhance the quality of phantom images.
Methods: Siemen Acuson X150 with curvilinear ultrasound transducer was used to scan the organs of interest (kidney, gallbladder and pancreas) of the ultrasound abdominal phantom. Different images at the different selected frequencies (2.5, 3.6 and 5.0 MHz) were created by fixing the position and the orientation of the transducer in each of the scanning process. Different-frequency images were generated and combined to produce composite (multi-frequency) image. Results: In this study, the quality of the composite image was evaluated based on signal-to noise ratio (SNR) and the obtained results were compared with the single frequency images. Besides, the comparison was also made in terms of overall image quality (noise and sharpness of organ outline) through perceived image quality analysis. Based on calculated SNR, the composite image of the kidney, gallbladder and pancreas recorded higher SNR value as compared to the single frequency images. However, through perceived image quality, most of the observers viewed that the quality of the composite image of the kidney, gallbladder and pancreas is poor as compared to the single frequency image. Conclusions: Image quality of ultrasound imaging is improved by combining multiple ultrasound frequency images into a single composite image. This is achieved as high SNR is obtained in the composite image. However, through perceived image quality, the overall image quality of the composite image was poor.

Matched MeSH terms: Signal-To-Noise Ratio
Fulltext A study of occupational noise exposure among public transportation workers in Malaysia

Siti Norhafiza Abd Razak, Nurul Hazwani Mohd Yusoff, Farah Hana Mukhtar, Norsehah Abdul Karim, Noor Hasyimah Abu Rahim

Journal of Occupational Safety and Health, 2015;12(1):69-72.
MyJurnal

Working for a minimum of 8 hours, 6 days a week might have exposed the workers of public transportation to
high noise risks. However, occupational exposures in their workplace have not been adequately characterized and
identified. Assessment of occupational noise exposure among workers at five public transportation stations was made
using Sound Level Meter and through questionnaire survey. The data obtained was combined to estimate the work
shift exposure level and health impacts to the workers by using statistical analysis. The respondents participated in the
survey to identify the symptoms of noise-induced hearing loss and other health-related problems. Results of the study
indicated that occupational noise exposure among workers for Mean Continuous Equivalent Level, Leq= 76.17 dB(A)
presents small risks of developing a hearing disability. Some of the workers show symptoms of noise-induced hearing
loss and are annoyed by the sources of noise present at the public transportation.

Matched MeSH terms: Hearing Loss, Noise-Induced; Noise, Occupational
Fulltext Noise measurement and awareness at construction site – A case study

Siti Nadia Mohd Bakhori, Mohamad Zaki Hassan, Feiruz Ab’lah, Aadil Nausherwan, Mohd Azlan Suhot, Mohd Yusof Daud, et al.

Journal of Advanced Research Design, 2017;31(1):9-16.
MyJurnal

The construction industry is one of the major sectors in Malaysia. Apart from providing
facilities, services and goods it also offers employment opportunities to local and
foreign workers. In fact, the construction workers are exposed to high risk of noises
being generated from various sources including excavators, bulldozers, concrete mixer
and piling machines. Previous studies indicated that the piling and concrete work were
recorded as the main source that contributed to the highest level of noise among
others. Therefore, the aim of this study is to obtain the level of noise exposure during
piling process and to determine the awareness of workers against noise pollution at
the construction site. Initially, the reading of noise level was obtained at construction
site by using a digital sound level meter (SLM) and noise exposure to the workers was
mapped. Readings were taken from four different distances; 5, 10, 15 and 20 meters
from the piling machine. Furthermore, a set of questionnaire was also distributed to
assess the knowledge of regarding noise pollution at the construction site. The result
showed that the mean noise level at 5 meters distance was more than 90 dB, which
exceeded the recommended level. Although the level of awareness of regarding the
effect of noise pollution is satisfactory but majority of workers (90%) still did not wear
ear muffs during working periods. Therefore, the safety module guidelines related to
noise pollution controls should be implemented to provide a safe working environment
and prevent initial occupational hearing loss.

Matched MeSH terms: Hearing Loss, Noise-Induced; Noise
Fulltext Blast injuries of the ear

Singh AP, Prasad U, Kumar N

Singapore Med J, 1983 Dec;24(6):367-73.
PMID: 6681493

Clinical synopsis and investigations on fourteen patients with blast injuries of the ear successfully treated at the ENT Unit of the University Hospital, Kuala Lumpur, revealed few interesting observations in addition to usual findings. The most outstanding one was the absence of sensorineural deafness, although it has been claimed as one of the most constant features. Conservative management alone was found to be of significant value.

Matched MeSH terms: Hearing Loss, Noise-Induced/diagnosis*
Signal-to-noise ratio estimation on SEM images using cubic spline interpolation with Savitzky-Golay smoothing

Sim KS, Kiani MA, Nia ME, Tso CP

J Microsc, 2014 Jan;253(1):1-11.
PMID: 24164248 DOI: 10.1111/jmi.12089

A new technique based on cubic spline interpolation with Savitzky-Golay noise reduction filtering is designed to estimate signal-to-noise ratio of scanning electron microscopy (SEM) images. This approach is found to present better result when compared with two existing techniques: nearest neighbourhood and first-order interpolation. When applied to evaluate the quality of SEM images, noise can be eliminated efficiently with optimal choice of scan rate from real-time SEM images, without generating corruption or increasing scanning time.

Matched MeSH terms: Signal-To-Noise Ratio*
Image signal-to-noise ratio estimation using Shape-Preserving Piecewise Cubic Hermite Autoregressive Moving Average model

Sim KS, Wee MY, Lim WK

Microsc Res Tech, 2008 Oct;71(10):710-20.
PMID: 18615490 DOI: 10.1002/jemt.20610

We propose to cascade the Shape-Preserving Piecewise Cubic Hermite model with the Autoregressive Moving Average (ARMA) interpolator; we call this technique the Shape-Preserving Piecewise Cubic Hermite Autoregressive Moving Average (SP2CHARMA) model. In a few test cases involving different images, this model is found to deliver an optimum solution for signal to noise ratio (SNR) estimation problems under different noise environments. The performance of the proposed estimator is compared with two existing methods: the autoregressive-based and autoregressive moving average estimators. Being more robust with noise, the SP2CHARMA estimator has efficiency that is significantly greater than those of the two methods.

Matched MeSH terms: Signal-To-Noise Ratio
Noise variance estimation using image noise cross-correlation model on SEM images

Sim KS, Nia ME, Tso CP

Scanning, 2013 May-Jun;35(3):205-12.
PMID: 22961698 DOI: 10.1002/sca.21055

A number of techniques have been proposed during the last three decades for noise variance and signal-to-noise ratio (SNR) estimation in digital images. While some methods have shown reliability and accuracy in SNR and noise variance estimations, other methods are dependent on the nature of the images and perform well on a limited number of image types. In this article, we prove the accuracy and the efficiency of the image noise cross-correlation estimation model, vs. other existing estimators, when applied to different types of scanning electron microscope images.

Matched MeSH terms: Noise; Signal-To-Noise Ratio
Image noise cross-correlation for signal-to-noise ratio estimation in scanning electron microscope images

Sim KS, Nia ME, Tso CP

Scanning, 2011 Mar-Apr;33(2):82-93.
PMID: 21381045 DOI: 10.1002/sca.20223

A new and robust parameter estimation technique, named image noise cross-correlation, is proposed to predict the signal-to-noise ratio (SNR) of scanning electron microscope images. The results of SNR and variance estimation values are tested and compared with nearest neighborhood and first-order interpolation. Overall, the proposed method is best as its estimations for the noise-free peak and SNR are most consistent and accurate to within a certain acceptable degree, compared with the others.

Matched MeSH terms: Noise; Signal-To-Noise Ratio
Autoregressive Wiener filtering in a scanning electron microscopy imaging system

Sim KS, Kamel NS, Chuah HT

Scanning, 2005 6 7;27(3):147-53.
PMID: 15934507

In this paper, we propose to use the autoregressive (AR)-based interpolator with Wiener filter and apply the idea to scanning electron microscope (SEM) images. The concept for combining the AR-based interpolator with Wiener filtering comes from the essential requirement of Wiener filtering for accurate and consistent estimation of the power of the noise in images prior to filter implementation. The resultant filter is called AR-Wiener filter. The proposed filter is embedded onto the frame grabber card of the scanning electron microscope (SEM) for real-time image processing. Different images are captured using SEM and used to compare the performances of the conventional Wiener and the proposed AR-Wiener technique.

Matched MeSH terms: Noise
Image signal-to-noise ratio estimation using the autoregressive model

Sim KS, Kamel NS

Scanning, 2004 7 31;26(3):135-9.
PMID: 15283250

In the last two decades, a variety of techniques for signal-to-noise ratio (SNR) estimation in scanning electron microscope (SEM) images have been proposed. However, these techniques can be divided into two groups: first, SNR estimators of good accuracy, but based on impractical assumptions; second, estimators based on realistic assumptions but of poor accuracy. In this paper we propose the implementation of autoregressive (AR)-model interpolation as a solution to the problem. Unlike others, the proposed technique is based on a single SEM image and offers the required accuracy and robustness in estimating SNR values.

Matched MeSH terms: Signal-To-Noise Ratio
Speckle Noise Diffusion in Knee Articular Cartilage Ultrasound Images

Shoaib MA, Hossain MB, Hum YC, Chuah JH, Mohd Salim MI, Lai KW

Curr Med Imaging, 2020;16(6):739-751.
PMID: 32723246 DOI: 10.2174/1573405615666190903143330

BACKGROUND: Ultrasound (US) imaging can be a convenient and reliable substitute for magnetic resonance imaging in the investigation or screening of articular cartilage injury. However, US images suffer from two main impediments, i.e., low contrast ratio and presence of speckle noise.
AIMS: A variation of anisotropic diffusion is proposed that can reduce speckle noise without compromising the image quality of the edges and other important details.
METHODS: For this technique, four gradient thresholds were adopted instead of one. A new diffusivity function that preserves the edge of the resultant image is also proposed. To automatically terminate the iterative procedures, the Mean Absolute Error as its stopping criterion was implemented.
RESULTS: Numerical results obtained by simulations unanimously indicate that the proposed method outperforms conventional speckle reduction techniques. Nevertheless, this preliminary study has been conducted based on a small number of asymptomatic subjects.
CONCLUSION: Future work must investigate the feasibility of this method in a large cohort and its clinical validity through testing subjects with a symptomatic cartilage injury.

Matched MeSH terms: Signal-To-Noise Ratio
Fulltext CT brain image advancement for ICH diagnosis

Shaik Amir NS, Kang LZ, Mukari SA, Sahathevan R, Chellappan K

Healthc Technol Lett, 2020 Feb;7(1):1-6.
PMID: 32190334 DOI: 10.1049/htl.2018.5003

A critical step in detection of primary intracerebral haemorrhage (ICH) is an accurate assessment of computed tomography (CT) brain images. The correct diagnosis relies on imaging modality and quality of acquired images. The authors present an enhancement algorithm which can improve the clarity of edges on CT images. About 40 samples of CT brain images with final diagnosis of primary ICH were obtained from the UKM Medical Centre in Digital Imaging and Communication in Medicine format. The images resized from 512 × 512 to 256 × 256 pixel resolution to reduce processing time. This Letter comprises of two main sections; the first is denoising using Wiener filter, non-local means and wavelet; the second section focuses on image enhancement using a modified unsharp masking (UM) algorithm to improve the visualisation of ICH. The combined approach of Wiener filter and modified UM algorithm outperforms other combinations with average values of mean square error, peak signal-to-noise ratio, variance and structural similarity index of 2.89, 31.72, 0.12 and 0.98, respectively. The reliability of proposed algorithm was evaluated by three blinded assessors which achieved a median score of 65%. This approach provides reliable validation for the proposed algorithm which has potential in improving image analysis.

Matched MeSH terms: Signal-To-Noise Ratio
Fulltext Image quality of coronary CT angiography (CCTA) using 640-slice scanner: qualitative and quantitative assessments of coronary arteries visibility

Shahril Shamsul, Akmal Sabarudin, Hamzaini Abdul Hamid, Norzailin Abu Bakar, Oteh Maskon, Muhammad Khalis Abdul Karim

Jurnal Sains Kesihatan Malaysia, 2020;18(2):49-57.
MyJurnal

The purpose of this study was to evaluate the image quality and diagnostic accuracy of coronary computed tomography angiography (CCTA) using 640-slice scanner. Advancement of multidetector computed tomography (MDCT) technology with higher spatial, temporal resolution, and increasing detector array have improved the image quality and diagnostic accuracy of CCTA. A total of 25 patients (12 men and 13 women) underwent CCTA examination was chosen and data was acquired by 640-slice scanner. All 16 segments of coronary arteries were evaluated by two reviewers using a 4-likert scale for qualitative assessment. In quantitative assessment, the evaluation of 4 main coronary arteries were analysed in terms of signal intensity (SI), image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). All 25 patients with a mean age of 52.88 ± 14.75 years old and body mass index (BMI) of 24.24 ± 3.28 kg/m2 were analysed. In qualitative assessment, from the total of 400 segments, 379 segments (95%) had diagnostic value while 21 segments did not have diagnostic value, which means 5% artefact was detected. In quantitative assessment, there was no statistical differences in gender, race, and BMI (p>0.05). Overall evaluation showed that higher SI at the left main artery (LM) at 393.7 ± 47.19. Image noise was higher at right coronary artery (RCA) at 39.01 ± 13.97. SNR and CNR showed higher at left anterior descending (LAD) with 12.73 ± 5.17 and LM 9.14 ± 4.2, respectively. In conclusion, this study indicates that 640-slice MDCT has higher diagnostic value in CCTA examination with 95% vessel visibility with 5% artefact detection.

Matched MeSH terms: Signal-To-Noise Ratio
Effect of miscentering and low-dose protocols on contrast resolution in computed tomography head examination

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
Ergonomic study on the manual component insertion lines for occupational health and safety improvements

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

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