• 제목/요약/키워드: 음 진동

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A Study on the Influence of Fire Service Budget for Fire Service Force (소방예산이 소방력에 미치는 영향)

  • Kim, Jin-Dong
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.4
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    • pp.67-74
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    • 2008
  • Because the fire service demands are increasing and forms are diversified, the first thing you must do is to make up the fire service budget to keep fire service power sufficiently. Such budget allocation leads to supply enough fire service people want and results in social welfare satisfaction. If the budget of fire service is not enough to meet with its power, sufficient security of the fire fighters would be impossible. Also, when the urgent disasters occur, the government cannot cope with them effectively. In fact, loss of many lives and properties took place in some cities and kuns because of that. The purpose of this study is to investigate the influence of fire service budget for fire service force. To do this, this study reviews fire service budget, fire service force. And this study sets up three hypotheses based on the theoretical backgrounds and the past research. The statistical method used for the verification of hypotheses is multiple regression analysis. The analysis showed that fire service budget per head variable was positive significant, fire service budget ratio variable was not significant. Also, public facilities tax variable was negative significant. Therefore, the analysis showed that public facilities tax couldn't fill the role as a earmarked tax.

Development of Base Concrete Block for Quiet Pavement System (저소음 포장용 기층 콘크리트 블록 개발)

  • Lee, Kwan-Ho;Park, Woo-Jin;Kim, Kwang-Yeom
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.1
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    • pp.35-42
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    • 2010
  • The rapid economic development induced the massive road constructions, becoming bigger and high-speed of the vehicles. However, it brings lots of social problems, such as air pollutions, traffic noise and vibration. Special concrete block for the base course of asphalt pavement is needed to decrease traffic noise such as tire's explosive and vehicles sound, applying Helmholtz Resonators theory to asphalt pavement. If it is applied to the area where it happens considerable noise such as a junction, the street of a housing complex and a residential street, it is one of considerable method to solve the social requirements of noise problem. This research examines couple of laboratory tests for the sound absorption effect of the concrete block and the base concrete block. There are specimens which is fixed hall-size, space, depth as the condition of this research, and these are analysed of noise decrease effect using different condition of the first noise of each vehicle. As a result of analysis data according to vehicle noise volume, measurement distance, a form and size of the hall using the base concrete block, the use of special concrete base showed a good alternative solution for decreasing traffic noise level, from 4 dB to 9 dB.

Postnatal Development of Echolocation Vocalizations in the Serotine Bat, Eptesicus serotinus (Chiroptera: Vespertilionidae) (문둥이박쥐(Eptesicus serotinus)의 생후 반향정위 발성 발달에 관한 연구)

  • Chung, Chul-Un;Han, Sang-Hoon;Kim, Sung-Chul;Lim, Chun-Woo;Cha, Jin-Yeol
    • Korean Journal of Environment and Ecology
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    • v.29 no.6
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    • pp.858-864
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    • 2015
  • Developmental changes in the vocal signals of serotine bats (Eptesicus serotinus) during their infancy were examined in this study. The analysis was conducted on 4 infant serotine bats from 1 to 40 days after their birth. Pulse duration (PD), pulse interval (PI), peak frequency (PF), maximum frequency ($F_{MAX}$), minimum frequency ($F_{MIN}$), and bandwidth (BW) were measured. As the bats grew, their vocalizations became increasingly consistent and similar to those of adults. For infant bats, PD and PI decreased as they grew older, whereas PF, $F_{MAX}$, $F_{MIN}$, and BW increased. The greatest change in vocalizations was observed between the $10^{th}$ and $20^{th}$ days after birth. Also, PF, $F_{MAX}$, $F_{MIN}$ and BW, which describe sound frequency, increased dramatically during the period between the $10^{th}$ and the $20^{th}$ days. In contrast, the greatest change in PD occurred between the $30^{th}$ and $40^{th}$ days after birth. The results collected in this study suggest that frequency increased as the contraction ability of the muscles developed by around 20 days of age. Muscle relaxation ability, which is related to PD, was found to develop significantly at 30 to 40 days of age. According to the results of this study, although 40 day-old infant bats are not yet able to fly, their vocal signals were similar to those of adults. This indicates that vocal development and flying activity develop separately in young bats.

Microwave Dielectric Properties and Far Infrared Spectrum of $(Pb_{1-x}Ca_x)(Fe_{0.5}Ta_{0.5})O_3$ Ceramics ($(Pb_{1-x}Ca_x)(Fe_{0.5}Ta_{0.5})O_3$ 세라믹스의 마이크로파 유전특성 및 Far Infrared Spectrum)

  • 박흥수;윤기현;김응수
    • Journal of the Korean Ceramic Society
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    • v.37 no.3
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    • pp.256-262
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    • 2000
  • The dielectric properties of complex perovskite ($Pb_{1-x}Ca_{x}$)($Fe_{0.5}Ta_{0.5}$)$O_{3}$ with >($0.5{\le}x{\ge}0.65$ were investigated at microwave frequencies. Dilectric constant decreased with increasing Ca content, and was directly proportional to the cube of average ionic ra야 of A-site. For the specimen of x=0.6 sintered at $1250^{\circ}C$ for 3 h in air, dielectric constant (k) of 63, QF of 11000 GHz, and the temperature coefficient of resonant frequency(TCF) of -14ppm/$^{\circ}C$ were obtained. As Ca content increased, TCF of the specimen negatively increased due to the reduction of the tolerance factor(t). Changes in intrinsic loss with varying Ca content was investigated by the infrared reflectivity spectra ranging 50 to 4000 $cm^{-1}$, which were calculated by the Kramers-Kronig analysis and classical oscillator model. The relative tendency of microwave dielectric properties of the ($Pb_{1-x}Ca_{x}$)($Fe_{0.5}Ta_{0.5}$)$O_{3}$ specimens calculated from the reflectivity data were in good agreement with the results by the post resonant method.

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Development of Automatic Calibration System for PC-Based Pure Tone Audiometer (PC 기반 순음청력검사기를 위한 자동보정시스템 개발)

  • Kim, Jin-Dong;Kang, Deok-Hun;Song, Bok-Deuk;Lee, Il-Woo;Kong, Soo-Keun;Kwon, Soon-Bok;Jeon, Gye-Rok;Shin, Bum-Joo;Wang, Soo-Geun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.7
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    • pp.2586-2594
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    • 2010
  • A pure tone audiometer should be able to produce both pure tone and masking noise with exact sound pressure level and frequency. For such purpose, it is unavoidable to periodically calibrates pure tone audiometer. However, manual acoustic calibration requires not only attention but also long time. It is possible to execute automatically calibration using software if it is PC-based pure tone audiometer. In this paper, we describe auto-calibration software for PC-based pure tone audiometer and dedicated sound level meter which has been implemented upon PC by us. To verify auto-calibration module, we examine whether output of PC-based audiometer calibrated through auto-calibration of this paper satisfies RETSPL of IEC or not.

A Study on the Selection of Hydrogen Refueling Station Locations within Military Bases Considering Minimum Safe Distances between Adjacent Buildings (인접 건물 간 최소 안전거리를 고려한 군부대 내 수소충전소 위치선정 연구)

  • Dong-Yeon Kim;Hyuk-Jin Kwon
    • Journal of Internet Computing and Services
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    • v.24 no.6
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    • pp.171-180
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    • 2023
  • Hydrogen energy technology is gaining importance in the era of the Fourth Industrial Revolution, offering military advantages when applied to military vehicles due to its characteristics such as reduced greenhouse gas emissions, noise, and low vibration. Korea's military has initiated the Army Tiger 4.0 plan, focusing on hydrogen application, downsizing, and AI-based smart features. The Ministry of National Defense plans to collaborate with the Ministry of Environment to expand hydrogen charging stations nationwide, anticipating increased deployment of military hydrogen vehicles. However, considering the Jet Fire and VCE(Vapor Cloud Explosion) nature of hydrogen, ensuring safety during installation is crucial. Current military guidelines specify a minimum safety distance of 2m from adjacent buildings for charging stations. Scientific methods have been employed to quantitatively assess the accident damage range of hydrogen, proposing a minimum safety distance beyond the affected area.

Studies of Long-term Variability of Methane in the Moo-Ahn Observatory Site in Korea (무안지역을 중심으로 한 메탄의 장주기적 농도변화 특성 연구)

  • Choi, Gyoo-Hoon;Youn, Yong-Hoon;Kang, Chang-Hee;Jo, Young-Min;Ko, Eui-Jang;Kim, Ki-Hyun
    • Journal of the Korean earth science society
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    • v.23 no.3
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    • pp.280-293
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    • 2002
  • In this study, we analyzed the long-term distribution patterns of $CH_4$ determined from the Moo-Ahn (MAN) observatory in relation with those derived from the world major background monitoring sites. Comparison of the data were made using those data sets collected for the period between Aug. 1995 to Dec. 1991. The mean $CH_4$ concentration of MAN observatory was measured to be 1898${\pm}$85.3 ppb, recording the highest concentration of all the monitoring sites. When the concentration of $CH_4$ for different stations was compared over latitudinal scale, its concentration appeared to increase systematically as a function of latitude with an exception of MAN (and the other Korean monitoring site at Tae Ahn). Moreover, such phenomenon was more distinctive in Northern than Southern Hemisphere. According to the analysis of the monthly distribution patterns of $CH_4$ at MAN observatory, its concentration level began to increase from the months of February/March and peaked during August. In addition, when the level of oscillation in monthly concentrations (between the maximum and minimum values) was checked, differences were significant between MAN and other monitoring stations. If the rate of concentration change was checked using the data sets collected for this limited time period in terms of linear regression analysis, results for MAN showed the highest annual increasing rate of 16.5 ppb. It is hence suggested that the largest variability in the $CH_4$ distribution patterns at MAN observatory may be reflected by the high irregularity in its source/sink processes.

Environmental Pollution in Korea and Its Control (우리나라의 환경오염 현황과 그 대책)

  • 윤명조
    • Proceedings of the KOR-BRONCHOESO Conference
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    • 1972.03a
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    • pp.5-6
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    • 1972
  • Noise and air pollution, which accompany the development of industry and the increase of population, contribute to the deterioration of urban environment. The air pollution level of Seoul has gradually increased and the city residents are suffering from a high pollution of noise. If no measures were taken against pollution, the amount of emission of pollutant into air would be 36.7 thousand tons per year per square kilometer in 1975, three times more than that of 1970, and it would be the same level as that of United States in 1968. The main sources of air pollution in Seoul are the exhaust has from vehicles and the combustion of bunker-C oil for heating purpose. Thus, it is urgent that an exhaust gas cleaner should be instaled to every car and the fuel substituted by less sulfur-contained-oil to prevent the pollution. Transportation noise (vehicular noise and train noise) is the main component of urban noise problem. The average noise level in downtown area is about 75㏈ with maximum of 85㏈ and the vehicular homing was checked 100㏈ up and down. Therefore, the reduction of the number of bus-stop the strict regulation of homing in downtown area and a better maintenance of car should be an effective measures against noise pollution in urban areas. Within the distance of 200 metres from railroad, the train noise exceeds the limit specified by the pollution control law in Korea. Especially, the level of noise and steam-whistle of train as measured by the ISO evaluation can adversely affect the community activities of residents. To prevent environmental destruction, many developed countries have taken more positive action against worsening pollution and such an action is now urgently required in this country.

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Study on Consequent Body Fat and Serum Lipid Metabolism after Cocoon Hydrolysate, Green Tea Leaves and Dietary Fiber Supplementation (누에고치 유래 실크 펩타이드와 녹차잎 및 식이 섬유소 보충이 체지방 및 혈청 지질 대사에 미치는 영향에 관한 연구)

  • Lee, Min-Sook;Kim, Dong-Myung;Cho, Byung-Nam;Koo, Seung-Ja;Jew, Sang-Sup;Jin, Dong-Kyu;Lee, Sung-Hee
    • Applied Biological Chemistry
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    • v.46 no.2
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    • pp.123-129
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    • 2003
  • This study is to investigate consequent nutrient intake status, Influences of body mass index (BMI) and serum lipid composition, and fat distribution on the cocoon hydrolysate, green tea leaves and dietary fiber supplementation. During 2 months of this research (April to May, 2002), 47 women aged 20 yr-30 yr (average age 26.2 yr) were selected as subjects. Nutrient intake was investigated by questionnaire and 24-hr recall method. Antropometric assessments of the subjects were investigated by SBIA method (Segmental bioimpedance assay, Inbody 3.0). The results were as follows: mean body weight was 60.7 kg, mean body height 161.7 cm and mean BMI 23.4. Status of energy intakes significantly decreased (p<0.01) and dietary fiber intakes significantly increased (p<0.001) after supplementation. BMI and WHR (waist-hip ratio) significantly decreased (p<0.01) and body fat significantly decreased after supplementation (p<0.001). Total cholesterol and LDL-cholesterol significantly decreased after supplementation (p<0.05). HDL-cholesterol was negatively correlated with BMI and WHR (p<0.01). LDL/HDL ratio was positively correlated with BMI (p<0.01) and WHR (p<0.05). Above results of this study show that low-molecule peptide, green tea leaves and dietary fiber supplementation-added routine diet improves lessening body fat distribution, total cholesterol, LDL-cholesterol. Especially, decrease of abdominal fat and WHR were notable. That meant decrease of risk factors.