• ETRI Journal
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• v.46 no.4
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• pp.619-632
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• 2024

Medical signal processing requires noise and interference-free inputs for precise segregation and classification operations. However, sensing and transmitting wireless media/devices generate noise that results in signal tampering in feature extractions. To address these issues, this article introduces a finite impulse response design based on a two-level transpose Vedic multiplier. The proposed architecture identifies the zero-noise impulse across the varying sensing intervals. In this process, the first level is the process of transpose array operations with equalization implemented to achieve zero noise at any sensed interval. This transpose occurs between successive array representations of the input with continuity. If the continuity is unavailable, then the noise interruption is considerable and results in signal tampering. The second level of the Vedic multiplier is to optimize the transpose speed for zero-noise segregation. This is performed independently for the zero- and nonzero-noise intervals. Finally, the finite impulse response is estimated as the sum of zero- and nonzero-noise inputs at any finite classification.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.1
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• pp.34-44
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• 1997

This study presents the recursive constraint bounding(RCB) method to reduce the cycle time in internal cylindrical plunge grinding process. This method can cope with process noise as well as modeling bias. The main features of RCB method are its utilization of measurements at the end of each cycle and its use of monotonicity analysis for determining the extremes of bias and noise. This method is investigated in simulation and evaluated by experiment in internal cylindrical plunge grinding operation. The results from simulation and experiment show that it is effective in reducing cycle time in spite of modeling uncertainty in the forms of process noise and modeling bias.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.113-118
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• 2017

In this paper, we propose a design procedure for determining the gate position robust to changes and inherent fluctuations in the process conditions during injection molding. To evaluate the robustness of the gate position, the signal-to-noise ratio is used, and noise conditions are implemented using orthogonal arrays, where the process variables are considered as noise factors and possible process fluctuations are set as the levels of the noise factors. To show the usefulness of the proposed robust design procedure, we apply it to a computer CPU baseplate. As a result, it is shown that a robust gate position can be determined that reduces the average warpage deflection by 2.4% and 1.7%, and the variance by 3.4% and 5.1%, compared to the two initial gate positions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1115-1119
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• 2007

As in many of the vehicle NVH issues, blower motor noise has been improved over the years through intensive R&D and production process improvement. Durability of motors, however, still has room for improvement according to customer surveys such as VDS. To investigate the noise issues of blower motors in view of durability, current production motors along with major competitor motors are tested. The noise after accelerated durability test shows that production motors are competitive in noise level with similar noise performance compared to initial measurement. The test result also provided guidelines to the durability development process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.477-481
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• 2009

In this paper the process of transmitting images signal restore to image corrupted by impulse noise proposed switching mean filter. these filter is differential size using the two state noise detection distinguishes noise pixel and noise free pixel. Follow the detected impulse noise density in the image remove the impulse noise using switching mean filter these substituted pixel in order to non-recursive and recursive form from control process of the next pixel comes to be used with neighbor pixel process. Through the simulation, we compared with the existing methods and capabilties.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.1
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• pp.100-107
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• 2018

Objectives: This study examines exposure to hazardous substances in the working environment caused by exposure to toxic substances produced in the aluminum die casting process in the automobile manufacturing industry. Materials and Methods: The exposure concentration levels, detection rates and time-trend of 15 hazardous factors in the aluminum die casting process over 10 years(from 2006 to 2016) were used as a database. Results: The study found that hazardous factors in the aluminum die casting process were mostly metals. The rate for detected samples was 70.6%(405 samples), and that for not detected samples was 29.4%. The noise for an eight-hour work shift showed a 49.7% exceedance rate for TLV-TWA. Average noise exposure was 89.0 dB. The maximum exposure level was 105.1 dB. Conclusion: The high numbers of no-detection rates for hazardous substance exposure shows that there is no need to do a work environment measurement. Therefore, alternatives are necessary for improving the efficiency and reliability of the work environment measurement. Moreover, to prevent noise damage, reducing noise sources from automation, shielding, or sound absorbents are necessary.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.1
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• pp.19-24
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• 2010

The noise of an running industrial fan or blower depends on the type of a fan, the machining accuracy and assembled conditions of each element, and buffs. Many studies have been carried out to reduce the noise through silencer in blower. In this study, 3 types of buffs which have different hole are employed in pipe of blower to study the influence the number and arrangement of buffs on the noise reduction at inlet and outlet in pipe. Commercial engineering software ANSYS was employed to analyze the characteristics and reduction ratio of pressure. Experimental results shows that optimal one can reduce the reduction ratio of noise as much as 16 percents in the laboratory. Good agreement was found between the analysed ratio of noise reduction and those obtained from the experiments.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.1
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• pp.101-108
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• 2019

In this study, the hole-cavity resonance technology and the micro pore stainless chip sintering technology were fused to develop silencers with excellent noise attenuation performance even at fluid pressures exceeding 30 bar for the first time at home and abroad. As a result of this study, the noise attenuation performance was greatly improved as reflection, loss, and resonance were made to occur thousands of times simultaneously when fluids pass through the sintered micro pore stainless steel chip sound absorber. The noise of the gas emitted from the bomb without the silencer was shown to be 125dB. And noise test conducted after installation of the silencer showed the noise of 67dB. Given the study results, the amount of noise was greatly reduced in the sintered silencer.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.3
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• pp.79-86
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• 1992

The cause of excess current noise which appears some times in RuO$_2$ thick film chip resistors and the process to reduce such noise are investigated. We observed that too large thermal expansion coefficients of resistor paste and electrode metal paste can induce the mechanical stress and microcracks in the contact region of the two sintered materials. Such microcracks result in the reduction of conduction paths in the sintered electrode and this provokes the increase of the resistance value and the current noise. Such excessive current noise induced by microcracks could be reduced or even eliminated by using an enlarged overcoat patterns in the plating process or by adding an additional annealing process before plating.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.8
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• pp.442-450
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• 2000

Active noise control is an approach to noise reduction in which a secondary noise source that destructively interferes with the unwanted noise. In general, active noise control systems rely on multiple sensors to measure the unwanted noise field and the effect of the cancellation. This paper develops an approach that utilizes a single sensor. The noise field is modeled as a stochastic process, and a time-adaptive algorithm is used to adaptively estimate the parameters of the process. Based on these parameter estimates, a canceling signal is generated. Opppenheim model assumed that transfer function characteristics from the canceling source to the error sensor is only propagation delay. But this paper proposes a modified Oppenheim model by considering transfer characteristics of acoustic device and noise path. This transfer characteristics is adaptively cancelled by adaptive model. This is proved by computer simulation with artifically generated random noise and sine wave noise. The details of the proposed architecture, and theoretical simulation and experimental results of the noise cancellation system for three dimension enclosure are presented in the paper.