Papers by Keyword: Noise

Abstract: In order to have a good workspace design, it takes a series of activities consisting of several stages. Starting from the design planning stage, design testing/ experimentation, design analysis, selection of the best design, to design implementation. This research was conducted to evaluate workspace designs using the Taguchi method. In this study, four factors were determined as elements of the workspace environment: the level of lighting, noise, temperature, and aroma of the room. Taguchi orthogonal array design produces 8 experiments obtained from a combination of 4 factors and 2 levels. Experimental activities in the form of the influence of the physical work environment on the resulting typing speed. The research sample in each experiment was 30 responses. The experimental results were analyzed using the Taguchi method with the help of Minitab software. In the analysis of the larger the better factor, based on the ranking, it is found that three factors have amajor influence on typing speed: lighting using room lights, not adding sound (noise), and regulating the room temperature to keep it cool. The ANOVA results show that lighting, noise, and temperature factors significantly affect typing speed. It is known that the calculated F value of the lighting factor is 42.10, noise is 12.22 and temperature is 14.45, all of which are greater than the F table of 4.07. The results of this study can be used as managerial evaluation material for companies to design workspaces by prioritizing bright lighting, not too noisy, and cool temperature of room.

Abstract: One of the environmental factors that can influence the onset of fatigue is noise exposure. Besides noise has a negative impact on everything from cognitive processes to mental and physical health. Noise's impact can be measured using brain activity and the waves it generates. The main goal of this article is to review how electroencephalography can be used to determine the impact of noise on cognitive performance. The method is based on bibliometric analysis stages, including literature study from the Scopus database and the snowball search method. The findings revealed that of the 30 articles examined, 28 used the experimental design method with continuous noise, and 10 used the time-frequency domain for feature extraction. According to the results of the study, there seems to be an increase in the use of EEG for performance measurement, such as mental fatigue, mental workload, working memory, attention, stress, and the presence of noise factors that influence cognitive performance.

Abstract: Premature babies born before 38 weeks have a high risk of dying, requiring urgent care. Premature babies receiving intensive care in incubators need certain temperature, humidity, and a quiet room. In addition, the baby should also be ensured that his body temperature remains normal during the treatment period. Based on the condition of these vulnerable babies, it is very necessary to have a temperature monitoring system in the incubator. Therefore, the purpose of this research is to develop a baby incubator monitoring system that still uses the manual method to make it faster, easier, and more practical. This module is a tool that works independently and is not part of the baby incubator. Therefore, any brand of the incubator can be monitored using this module. The system in this module is wireless and uses a Wi-Fi network for data transmission. By using several ESP32 modules assembled into a central system, the data obtained from monitoring each sensor will be processed by the ESP32 which functions as a client, and collected at the central point of the ESP32 which functions as a server using the internal wifi network of the ESP32 itself as data transmission. The data from the server will subsequently be shown on the TFT Nextion display. Based on the overall measurement results using 2 baby incubators, the highest error values ​​were 1.387% for the incubator temperature parameter, 3.911% for the skin temperature parameter, 10.5% for the humidity parameter, and 25.692% for the noise parameter. The results showed that the module that was made still contained errors in each measurement. The results of this study will assist nurses in more simply and swiftly monitoring premature newborns.

Abstract: Successes of GaN and SiC electronics in high frequency, large power realm indicate that, the GaN/SiC hetero-structures can be used to design the impact avalanche transit time (IMPATT) diodes operating at Terahertz range, of which holds advantages over homo-structural counterparts in lower noise and reduced tunnel current. Here, the (n)GaN/(p)SiC and (p)GaN/(n)SiC double drift region (DDR) IMPATT diodes operating at 0.85 THz are proposed based on the quantum corrected drift-diffusion (QCDD) model, the performance parameters of static state, large signal and noise properties of the studied devices such as peak electric field intensity, breakdown voltage, optimal negative conductance, output power, conversion efficiency, admittance-frequency relation, quality factor, noise electric field, mean-square noise voltage per band-width and noise measure were numerically calculated and analyzed, which can guide to optimize the GaN/SiC IMPATT diodes.

Abstract: This paper examines the characteristics of stick-slip phenomena between the glass plate and Magneto-Rheological Elastomer (MRE) surface. Stick-slip phenomena are the spontaneous jerking motion that occurs while two objects are sliding over each other, usually accompanied by noise. Stick-slip is generated when it involves discontinuous frictional degradation when moving from static friction to dynamic friction. The phenomena can lead to uneven wear patterns, vibration and squeal noise which cause a shorter lifespan for the corresponding mechanical elements. MREs are kind of function materials to consist of a polymeric matrix with embedded ferromagnetic particles. Mechanical properties of the MREs can be controlled by the application of magnetic fields. The magnetic field-based controllability can be applied to the control of stick-slip phenomena. The friction experiment is conducted with the Reciprocating Friction Tester (RFT). The sliding speed of the RFT should be in low-speed conditions in order to make the stick-slips relatively easy to occur. A uniform magnetic field and a weight load are applied to the MRE sample to observe the effect of various experimental parameters on the movement of the stick-slip. In addition, frictional sounds due to the stick-slip phenomenon under different loads and magnetic field strength are measured and analyzed. The results of this experiment show that as the strength of the magnetic field increases, the difference in stiffness between the wipers-glass decreases, mitigating fricatives. The result is expected to be well applied to low-noise automotive wipers based on the controllability of friction behavior and squeal noise.

Abstract: CBCT is a modernized technology in producing radiograph image on dentistry. The image quality excellence is very important for clinicians to interpret the image, so the result of diagnosis produced becoming more accurate, appropriate, thus minimizing the working time. This research was aimed to assess the image quality using the blank acrylic phantom polymethylmethacrylate (PMMA) (C­₅H₈O₂)_n in the density of 1.185 g/cm³ for evaluating the homogeneity and uniformity of the image produced. Acrylic phantom was supported with a tripod and laid down on the chin rest of the CBCT device, then the phantom was fixed, and the edge of the phantom was touched by the bite block. Furthermore, the exposure of the X-ray was executed toward the acrylic phantom with various kVp and mAs, from 80 until 90, with the range of 5 kV and the variation of mA was 3, 5, and 7 mA respectively. The time exposure was kept constant for 25 seconds. The samples were taken from CBCT acrylic images, then as much as 5 ROIs (Region of Interest) was chosen to be analyzed. The ROIs determination was analyzed by using the ImageJ® software for recognizing the influence of kVp and mAs towards the image uniformity, noise and SNR. The lowest kVp and mAs had the result of uniformity value, homogeneity and signal to noise ratio of 11.22; 40.35; and 5.96 respectively. Meanwhile, the highest kVp and mAs had uniformity value, homogeneity and signal to noise ratio of 16.96; 26.20; and 5.95 respectively. There were significant differences between the image uniformity and homogeneity on the lowest kVp and mAs compared to the highest kVp and mAs, as analyzed with the ANOVA statistics analysis continued with the t-student post-hoc test with α = 0.05. However, there was no significant difference in SNR as analyzed with the ANOVA statistic analysis. The usage of the higher kVp and mAs caused the improvement of the image homogeneity and uniformity compared to the lower kVp and mAs.

Abstract: This study presents a real-time method for determining the thickness of each layer in multilayer thin films. Artificial neural networks (ANNs) were introduced to estimate thicknesses from a transmittance spectrum. After training via theoretical spectra which were generated by thin-film optics and modified by noise, ANNs were applied to estimate the thicknesses of four-layer nanoscale films which were TiO₂, Ag, Ti, and TiO₂ thin films assembled sequentially on polyethylene terephthalate (PET) substrates. The results reveal that the mean squared error of the estimation is 2.6 nm², and is accurate enough to monitor film growth in real time.

Abstract: Images are susceptible to degradation by noise from different sources as they undergo various processes. The effect of noise degradation affects the visual information fidelity, structural content and the decryption performance of an image encryption algorithm. In this paper, the effects of noise attacks on the performance of a hyperchaos-based digital image encryption algorithm is evaluated. In hyperchaos-based encryption algorithm, chaotic dynamics are used to encrypt the pixels of images. Two noise models, namely Gaussian noise and salt and pepper noise were added to test images, prior to encryption operations, in order to test for the robustness of the algorithm to noise attacks. The mean square error, peak signal – to – noise ratio, structural content and normalized correlation coefficient of the plain and decrypted images were evaluated. The results obtained indicated that noise has insignificant effect on the decryption performance of the algorithm, as the noise-degraded images and their decrypted counterparts were very identical. Thus, the image encryption algorithm is tolerant of noise and can therefore be used in noisy channels.

Abstract: Getting rid of unwanted noise in car compartment is necessary and really significant measure for automotive makers. This research was directed to produce nonwoven material from Kenaf fiber using the needle-punching machine and the ability of the produced material to absorb sound will be tested. The performance in sound absorption of the sample was analyzed by the sound absorption coefficient (SAC) and noise reduction coefficient (NRC) using the impedance tube test referring to ASTM E1050-98. The sound absorption frequencies were evaluated utilizing the two-microphone transfer function technique in the impedance tube that has a 100 mm diameter for low frequency and 28 mm for high frequency, 0 Hz to 4000 Hz respectively. The physical examination also was executed according to ASTM D1772 to determine the density and the thickness of each sample. The parameter verified in this research is the number of layers to form the samples and it also were compared with the commercial products. As the outcome of this research, the sound absorption coefficient (SAC) showed that the sound reduction coefficient value was increased as the number of layers of the sample increase. In summation, the result also proved that the denser the samples, the higher the absorption coefficient value. On the other hand, for the noise reduction coefficient (NRC), overall result showed slight differences between each sample. The result is due to the rating is an average, two materials with the same rating might not perform the same. Referring to the previous research, the sample with higher areal density is dependable for higher sound reduction and there is a negative relationship between area density and bulk density of needle-punched nonwoven and sound reduction. With the rise in the number of density of nonwoven fabric, the sound reduction through the fabric increases at first but after the maximum it remains almost unaffected.

Abstract: Si/SiC heterostructural impact avalanche transit time (IMPATT) diode indicates of important applications in Terahertz (THz) power source, integrated circuit etc. In this paper, the (n)Si/(p)4H-SiC, (n)Si/(p)6H-SiC, (n)Si/(p)3C-SiC heterostructural double drift region IMPATT diodes operating at the atmospheric window frequency of 0.85 THz are designed by the drift-diffusion model while their static state, large signal and noise properties are numerically simulated. The performance parameters of the studied devices such as breakdown voltage, peak electric field strength, optimal negative conductance, output power, power conversion efficiency, admittance-frequency relation, quality factor, noise electric field, mean-square noise voltage per band-width and noise measure were calculated and compared. This method can guide for optimizing the Si/SiC heterostructural IMPATT device in the future.