• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.660-670
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• 2021

As various people use the cafe for various purposes, it is difficult to hear conversations with the accompanying people due to the noise and background music of people around the respondents. In addition, there is a need for improvement related to the noise and sound inside the cafe, such as making it easier to hear the conversations of nearby users. 212 adult men and women participated in the questionnaire on the survey on cafe acoustics and noise conditions. As a result of the survey, about two-thirds of the respondents said that they did not prefer noisy cafes, and that the noise of cafes had a negative effect. The major source of noise in cafes is the sound of people around users, and more than 40 % of the respondents said that they could not hear well the sound of conversations with their accompanying people due to the sounds of those around them, or that they were concerned about their own conversations being transmitted to those around them. As a result of the survey on cafe sound and noise, it was found that improvements were needed to secure the voice privacy of cafe users as well as the voice intelligibility.

• Journal of the Ergonomics Society of Korea
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• v.15 no.2
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• pp.185-192
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• 1996

EEG(electroencephalogram) is characterized with auditory emotion in this study. Twenty university students participated in this study. The auditory stimulus was the natural sounds such as creek sound, clash, machining noise, and etc. They can cause the positive and negative emotion. EEG characteristics according to positive and negative auditory stimuli is tried to observe statistic difference. The significant difference is shown depending on the localized area. The auditory paraameters of EEG variation is examined for defining human emotion qualitatively. The results shows that the alpha and the beta at temproal area may be thd determinat of human auditory emotion.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3181-3183
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• 2000

As the fact that the simple data of text and sound in early year have been changed to be high quality images and sounds. PLL(Phase-Locked Loop) system plays an important role in communication system. VCO(Voltage Controlled Oscillator) is the most important part in PLL system because it can have critical effects on operation of PLL. Recently, it has been raised the necessity of high speed and high accuracy circuit application. In this paper, a new differential voltage clamped VCO using negative-skewed path is suggested. Using a dual-delay scheme to implement the VCO, higher operation frequency and wider tuning are achieved simultaneously. The dual-delay scheme means that both the negative skewed delay paths and the normal delay paths exist in the same ring oscillator. The negative skewed delay paths decrease the unit delay time of the ring oscillator below the single inverter delay time. As a result, higher operation frequency can be obtained. The whole characteristics of VCO are simulated by using HSPICE. Simulation results show that the resulting operating frequencies are 50% higher than those obtainable from the conventional approaches.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.241-255
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• 2021

The human auricle is the first part to receive sound from the outside. In this part, the frequency range of human recognizable form is divided and organized. In this study, we propose modeling by applying a single sound source to the surface of the human auricle. This means that when the sound pressure of a low frequency (low frequency) sound enters the pinna, the impedance felt at the tip of a part of the non-linear surface of the pinna is mainly due to the tensile force at the end of the part of the non-linear surface of the pinna. By expressing the situation of moving at a very small speed, the characteristic impedance of the pinna was confirmed to be negative infinity, and it was also confirmed that the speed at the tip of a part of the non-linear surface of the pinna was 0 in the anti-resonance state. It was found that the wave propagation phenomenon that determines the characteristics of the filter is determined by how large the wavelength, kL, is compared to the length of the tip of a part of the non-straight surface of the pinna. Humans first receive sounds from outside through their ears. The auricle is non-linear and has a curved shape, and it is known that it analyzes frequencies while receiving external sounds. The human ear has an audible frequency range of 20Hz - 20,000Hz. Through the study, we applied the characteristics of the notch filter to hypothesize that the human audible frequency range is separated from the auricle, and applied filter theory to analyze it, and as a result, meaningful results were obtained. The curved part and the inner part of the auricle function as a trumpet, collecting sounds, and at the same time amplifying the weak sound of a specific band. The point was found and the shape of the envelope detected in the auricle was found. Selectivity for selecting sounds coming from the outside is the formula of the pinna that implements the function of Q. The function of distinguishing human-recognizable sound from the pinna from low to high through frequency analysis is performed in the pinna, and the 2-3kHz area, where human hearing threshold is the most sensitive, is also the acoustic impedance of the most recessed area of the pinna. It can be seen that starting from.

• Korean Journal of Environment and Ecology
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• v.36 no.3
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• pp.350-357
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• 2022

A national park is a place to conserve natural resources and visitors to experience nature, and thus, it is necessary to identify the noise distribution characteristic in the national park and preserve and restore the soundscape. However, most national parks in Korea are exposed to noise, leading to negative perceptions of the national park's soundscape and affecting the ecosystem. Many national parks in other countries have investigated the ecosystem impacts caused by noise and have performed various management to reduce the noise. However, in Korea, there is still a lack of awareness of the effect on the ecosystem, overlooking the need for soundscape management. Therefore, in this study, we developed a noise map of Mudeungsan National Park to investigate the quantitative impact of noise on visitors and the ecosystem. Also, we measured the trail's soundscape to describe a sound grade classification, and the soundscape of main spots in the park was recorded for a year and then analyzed. Finally, the sound resource distribution map was described, which can be used as preliminary data to determine the national park's sound distribution characteristics and manage the soundscape.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.177-181
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• 1984

This study was to confirm the influence of intracanal instrumentation whether the pulp infection could be extended to periapical tissue. Fifty three teeth (24 badly decayed and infected, 29 sound teeth) were employed for this experiment and grouped as follows; 1. The specimen taken from the tip of 12 infected pulp in which reamer was inserted to the canal up to apical 1/3 and cultured as long as 48 hours. After 24 hours culture 11 cases were positive and 1 ease was negative but the time of incubation elapsed as 48 hours a negative case turned to positive. 2. Broth immersed paper disc was placed for 1 minute on the tip of 12 infected teeth with a reamer inserted to the apical end and cultured as usual manner in the incubator. At 24 hour culture the growth was significant in 9 cases and after 48 hours total 12 cases were positive. 3. Reamer was inserted to apical 1/3 on 14 sterile pulp canals and specimens obtained from the root tip were cultured for 24 and 48 hours. The results on both group were negative. 4. Similar maner with No.3 except reamer tip was rest exactly at the apex revealed only 2 cases of positive at 48 hour culture. 5. The tip of 24 reamers which reached to apical 1/3 and apex of infected canal were cultured for 24 and 48 hours. At 24 hour culture the growth was evident. 6. The tip of 14 reamers which inserted to apical 1/3 of sterile canal showed negative at 24 hour culture. The 15 cases of the tip which reached to the apex of sterile canal were found negative except 3 positive cases at 48 hour culture.

• Journal of Korea Multimedia Society
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• v.19 no.4
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• pp.756-764
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• 2016

In this paper, we present electroencephalography (EEG)-based power spectra analysis and auditory stimuli methods as coping mechanisms for disgust affection and phobia. Disgust affection is a negative emotion generated from trying to eliminate something harmful to one. It is usually related to mental illnesses such as obsessive-compulsive disorder, specifically phobia and depression. In our experiments, participants watched videos on horrible body mutilation and disgusting creatures, with either the original sound track or relaxing and exciting music as auditory stimulation. After watching the videos with original sound track, the participants watched the same video with a different audio background, such as soothing or cheerful music. We analyzed the EEG data utilizing relative power spectra and examined survey results of the participants. The results demonstrated that disgust affection is decreased when participants watched the video with relaxing or exciting music instead of the original soundtracks. Moreover, we confirmed that human's brainwave reacts according to types of audio and sources of disgust affection.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.1
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• pp.19-28
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• 1999

This survey is to investigate the effect of plants and waterscape facilities on the thermal indoor environment and to provide basic data for proper plant cultivation to enhance indoor landscape. The survey of the measure of comfort on the indoor environment for the residents of Taegu shows that the measure of comfort on the thermal-environment, which consist of temperature and humidity, has more negative responses than the measure on lighting . are . sound environment, which consists of air freshness, lighting condition and sound environment. The experiments on the effect of the amount of leaves and the distance of plants on the indoor thermal-environment are made. The experimental results illustrate that, as the capacity of a plant becomes greater and the distance from the plant shorter, the falling effect of temperature and the rising effect of humidity on the top of the plant are taken higher than on the side of the plant. When the same amount of leaves is set up, the distance range of the rising effect of humidity becomes wider than that of the falling effect of temperature. The investigation of the effect of waterscape facilities on the indoor thermal-environment shows that temperature and humidity of the space with installed waterscape facilities are lower and higher than without facilities, respectively.

• Journal of ILASS-Korea
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• v.4 no.3
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• pp.32-41
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• 1999

In this research, internal-mixing twin-fluid atomizer using sonic energy is designed and manufactured. We are trying to intimate high efficiency twin-fluid atomizer to obtain good liquid atomization in the low pressure region. Define of geometric form of atomizer, characteristics of spray is influenced by position, depth and height variation of cavity resonator, variation of sound intensity and resonant sound frequency with liquid flow rate. The liquid atomization is promoted by multi-stage disintegration of mixing flow of gas with liquid and the optimum condition of position and depth of cavity resonator according to sonic energy is obtained from the condition at a=2.5mm and L=2mm. The velocity distribution of droplets shows negative value due to recirculation region at the center of axial, and as the radial direction distance is far, the velocity distribution of droplets decrease slowly after having a maximum value. However velocity and SMD show nearly uniform distribution at the down stream and as result compared to Nukiyama and Tanasawa's equation. atomization of mixing flow with air and liquid dispersing from the outlet of the nozzle is promoted by the effect of collision at the cavity resonator.

• Korean Journal of Agricultural Science
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• v.28 no.1
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• pp.48-58
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• 2001

This study was conducted to investigate the effects of environmental sound rice farming method on the productivity of rice industry which may result in impacts on the staple food securities. Recently fanners have been concerned about adopting new rice cultivation method such as organic and low input farming system in which fertilizer and pesticide can be substantially reduced so as to alleviate the burden of agro-ecosystem. However, It has been argued about whether or not there are negative impacts on the self sufficiency rate of food, income of farm household and technological adaptability. Therefore this study examined the productivity trend of environmental rice farming system and predicted the long term rice self-sufficiency rate when environmental rice farming system are adopted by assuming various scenarios. It was estimated that rice self-sufficiency rate can be decreased up to 52.2% by 2010. Based on the analysis of results, policy recommendations for environmentally sound rice farming were suggested as follows: 1) gradual adopting and transferring of environmental rice cultivation method, 2) increasing profitability of rice growing fanners 3) developing the farm level technology specific to Korean farming condition, 4) institutionalization of direct payments for encouraging environmental rice fanning.