• Title/Summary/Keyword: Sound system

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Effect of Different Cropping System and Soil Management on Soil Chemical and Microbiological Quality Assessment in the Daekwanryung Upland Soil (대관령(大關嶺) 지역에서 작부체계 및 토양관리 방법의 차이가 토양화확성 및 미생물상에 미치는 영향)

  • Yun, Sei-Young;Kim, Jeong-Je;Yang, Jae-Wei;Jung, Yeong-Sang;Choi, Joong-Dae
    • Korean Journal of Soil Science and Fertilizer
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    • v.32 no.3
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    • pp.312-318
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    • 1999
  • These experiments were conducted to determine the effects of soils treated with different soil management, methods, fertilizers and crops on soil microflora and its number for constructing the environmentally sound agriculture modeling of the upland soils. These experiments show that physico-chemical soil characteristics was different in upland soils treated with different soil managements and fertilizers applied. Also soil microflora and its number were effected from crops cultivated with different soil managements in these experiments. The number of Erwinia sp. in chinese cabbage cultivated field on Daekwanryung especially was apparently increased in soil cultivated with potato relative to corn. It was appeared that the number of Fusarium sp. in soil was more effected from kind of fertilizer applied than crops cultivated.

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Effects of Body Condition Score and Estimation of Growth Curves for Chest Girth and Ultra Sonic Longissimus Muscle Area, Backfat Thickness and Marbling Scores in Hanwoo(Korean cattle) Cows (한우 암소의 흉위, 초음파 측정 배장근단면적, 등지방두께, 근내지방도에 대한 발육곡선 추정 및 신체충실지수 효과)

  • Lee, Deuk-Hwan;Lee, Gil-Hwan;Cho, Chung-Il;Kim, Nae-Soo
    • Journal of Animal Science and Technology
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    • v.50 no.5
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    • pp.581-590
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    • 2008
  • Growth curves for ultrasonic carcass traits such as longissimus muscle area, backfat thickness and marbling score as well as chest girth which was simultaneously measured when carcass traits were investigated using ultrasound measuring technique were estimated to identify growth patterns and to adjust maturing effects in order to evaluating genetic merits on cows in farming basis. 27,410 records from 22,451 cows on which of 15~90 month of age were investigated from the national wide of Korea using by ultrasonic scanning techniques by the skilled persons from 2002 to 2007. Van Bertalanffy growth function was applied for estimating growth curves on these traits. Carcass traits and chest girth would be linearly increased by body condition score. It might be used for multiplicative correction factors for pre- adjustment on the body condition scores. Growth pattern on chest girth would be quickly reached to mature size and stable on after reached to asymptotic mature size. Longissimus muscle area would also be reached to mature size but little smoother than chest girth. Otherwise, growth curve on backfat thickness would be steadily increasing up to 7 years of age. It also showed large individual difference by way of mean square error. Marbling score would be steadily increased but sharper than those on backfat thickness. It would be reached to mature size up at 5 years of age. Those growth curves would be used for correcting function on age at investigating on genetic evaluation system.

On-site Application of a Vehicle Tunnel Ventilation Simulator (도로터널 환기시뮬레이션 모델 현장적용 연구)

  • 이창우;김효규
    • Tunnel and Underground Space
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    • v.11 no.4
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    • pp.319-327
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    • 2001
  • Introduction of new design tools has been required to optimally design and operate the ventilation system of long vehicle tunnels.. The demand has led to wide spread use of the simulation technique throughout the would to analysis the dynamic relationship among the variables associated with vehicle tunnel ventilation. This paper aims at performing on-site study at local tunnels to test the applicability of NETVEN, a simulation model vehicle tunnel ventilation. The study was carried out at four urban as well as highway tunnels model of vehicle tunnel ventilation. The study was carried out at four urban as well as highway tunnels employing different ventilation systems as well as traffic methods. There were some discrepancies sound between the simulation output and measurements and the following four factors are considered to mainly cause those disagreement. (1) The real situation shows distinctive transient and retarding characteristics with respect to air flow and contaminant dispersion, while ventilation forces are not steady-state and in particular those traffic and climatic variables show significant instantaneous variation. (3) Near the exit portal, the CO levels show bigger differences. The general trend is that data with higher CO concentrations carry bigger discrepancies. Turbulent diffusion is though to be the main reason for it and also contribute to the fact hat the highest CO concentrations are found at the locations somewhat inward, not at the exit portals. (4) Higher traffic rate results in higher discrepancies of ventilation velocity. Along with the exhaust characteristics, the vehicle aerodynamic characteristics need to be studied continuously in order to reduce the velocity disagreement.

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A Survey on Asbestos Exposure Possibility in Indoor and Outdoor Environments of Childcare Centers (어린이집 실내·외 석면노출 가능성 조사에 관한 연구)

  • Park, Whame;Son, Byeung-Hun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.24 no.2
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    • pp.122-129
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    • 2014
  • Objectives: Because of its properties such as resistance to heat, chemicals and corrosion; tensile strength; sound absorption; and affordable price, asbestos has been widely used as a building material, fire resistant and retardant, thermal and heat insulator, soundproofing material, and electrical insulation. Since the prolonged inhalation of asbestos can cause serious illnesses such as lung cancer, mesothelioma, and asbestosis after an incubation period of 20 to 40 years, the mineral was classified as a Group 1 carcinogen by the International Agency for Research on Cancer, an intergovernmental agency forming part of the World Health Organization. Children and infants are more at risk than are adults if they are exposed to carcinogens, due to aweaker immunity that has not yet been fully developed. Most childcare centers are operated all day and children tend to spend a great amount of time in the centers. This is why it is important for them to be systematically isolated from environments that may expose them to asbestos. Materials: In order to understand both indoor and outdoor hazards to which children may have been exposed, the study focused on actual surveys of asbestos used in childcare centers, paying special attention to slate-roofed buildings in the vicinity of the centers. Results: A survey of a total of 211 childcare centers showed that the buildings of 18.1% of the centers contained asbestos, with 60.53% of the material being found in classroom ceilings. "Tex" was the most used material for ceilings, making up 89.47% of all ceilings. An outdoor survey showed that childcare centers in Daegu Metropolitan City had an average of 143 slate-roof buildings within a distance of 1km. Conclusions: Buildings housing mainly toddlers, children, teenagers and others more vulnerable to the toxicity of asbestos are not subject to asbestos investigation by law. A legal and practical basis for asbestos control is required for such buildings. In particular, housing materials which contain asbestos in day care centers require asbestos control. GIS should be used to identify the location of buildings with slate roofing materials in the vicinity of daycare centers in order to gauge toxicity of exposure to asbestos caused by potential asbestos friability possibility in outdoor conditions.

A Study for Improving in Greening System and Method to Revitalize Wall-planting (벽면녹화 활성화를 위한 제도적 개선방안 및 조성방향에 관한 연구)

  • Han, Seung-Ho;Kim, Sun-Hae
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.9 no.2
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    • pp.59-71
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    • 2006
  • Due to the rapid process of industrialization the cities of Korea confront changes of climate, destructions of the habitate and decrease of the green. Recently Seoul and other local governments have implemented policies and projects to improve the environmental surroundings. In reality, however, those policies and projects face difficulties in the course of implementation. The fact that there are no concrete regulations and specific legal procedures turns out to be one of the main difficulties. The aim of this study is to present specific plans and methods of wall-planting and to provide basic guidelines for the future direction of wall-planting and offer ideas of facilitating wall-planting. This study is based on questionnaires from specialists of landscape architecture through individual interviews and/or e-mails. The questionnaire is consisted of following 4 sections. 1. Show the experts current regulations and/or legal procedures and ask them improvements and suggestions. 2. Ask them choose matters of the highest priority by using Ricardo's diagram method. 3. Ask them to make a graded list in terms of the location and method of wall-planting. 4. Study the maketability of the wall-planting products currently in circulation. The city of Seoul and the Ministry of Environment recommend that trellis and/or planting inducement structures be installed on the building wall by regulation. The specialists responded to the questionnaire advocate that green wall without trellis should be allowed as green zone. Therefore regulations concerning the wall-planting should be determined specifically according to the characteristics of individual plants and walls. It has been urged that legal aid and social support must be reinforced to establish rules dealing with wall-planting. The respondents also point out that significant cutting down of the tax is far more effective in accelerating the wall-green instead of administrative support. The highest priority in terms of planting has been given to sound-proof wall, retaining wall and building wall. Concerning the maketability of the wall-planting products, panel products are recommended for early-planting and building planting. It has been suggested that the research and study of new materials and species be done in advance.

The effects of bamboo salt solution on remineralization of artificial caries-like lesions (죽염이 초기인공우식법랑질의 재광화에 미치는 영향)

  • Oh, Han-Na;Hong, Suk-Jin;Lee, Hye-Jin;Choi, Choong-Ho
    • Journal of Korean society of Dental Hygiene
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    • v.12 no.2
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    • pp.335-343
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    • 2012
  • Objectives : The aim of this investigation was to evaluate the remineralization effect of Bamboo salt and NaF+Bamboo salt solutions on bovine enamel formed incipient artificial enamel caries by microcomputed tomography (micro CT). Methods : Experimental solutions were distilled water(negative control), 2% sodium fluoride solution (2% NaF group), 3% bamboo salt solution (3% BS group) and the solution mixed 2% sodium fluoride solution and 3% bamboo salt solution (2% NaF+3% BS group). Specimens were prepared from extracted bovine teeth and divided into 4 groups of 10 specimens each by randomized blocks according to density. Then the specimens surface were divided equally into three parts to observe sound enamel area, incipient enamel carious area and remineralized enamel area. Only one-third of specimen surface was coated with nail varnish and these were exposed to a lactate carbopol buffer system for 72 hours. Then one-half of the demineralized enamel area was coated with nail varnish. The specimens were carried out under pH cycling model for 14 days as follows; samples were immersed in each experimental solution for 2 mins 3 times per day, demineralized for 4 hours and in mixed saliva for the remaining hours. After pH cycling, density was measured using micro CT. Results : All experimental groups showed remineralization effects except for negative control group(p<0.05). The differences of density after experimental solution treatment were statistically significant difference among 4 groups (p<0.01). The density difference values of groups were $0.04{\pm}0.01$ in negative control group, $0.19{\pm}0.01$ in 2% NaF group, $0.14{\pm}0.01$ in 3% BS group, and $0.21{\pm}0.01$ in 2% NaF+3% BS group. Conclusions : The bamboo salt solution showed remineralization effects on incipient artificial enamel caries and the solution mixed sodium fluoride solution and bamboo salt solution showed more remineralization effects than the bamboo salt solution. Thus, it is suggested that bamboo salt can be used as remineralization agent in incipient enamel caries lesion.

The Ability of Auditory Stimuli to Mask Siren Sounds in a Vehicle Graphic Simulator (자동차 그래픽 시뮬레이터에서 사이렌 소리 자극에 따른 청각 자극의 마스킹 효과)

  • Park, Jung-Sun;Kim, Gyu-Beom;Jo, Hyeong-Seok;Kim, Gyeong-Rae;Kim, Jun-Hyeong;Min, Byeong-Chan
    • Science of Emotion and Sensibility
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    • v.22 no.3
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    • pp.47-54
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    • 2019
  • We examined previous studies of the correlation analysis of heart rate variability as a method to reduce the stress caused by outside noise during driving, and we investigated whether there are electrocardiographic changes when drivers play music, which provides a stable sound source amid the noise. Because the number of cars increases every year, drivers and passengers show an increase in stress caused by outside noise. The stress from outside noise while a person is driving can cause several disorders, such as anxiety, immunosuppression, depression, and heart disease. Subjects in this study operated a vehicle simulator to reduce the stress from outside noise and were given different auditory stimuli, and we studied the drivers' responses to the stimuli. Repeated-measures analysis of variance revealed a significant differences between subjects exposed to different auditory stimuli (ρ < 0.05). Through post hoc analyses, we examined these differences. We found significant differences between factor 1 (stability) and factor 2 (simulation driving), between factor 1 (stability) and factor 3 (driving + police siren), and between factor 1 (stability) and factor 4 (driving + police siren + music). In addition, the factor that produced the highest level of sympathetic nervous system activity was factor 4 (driving + police siren + music), followed by factor 3 (driving + police siren), factor 2 (driving), and factor 1 (stability). In conclusion, even when a police siren was heard during driving, there were no significant differences on electrocardiograms (ECGs). In addition, even when the siren was heard over the music, there was no difference on the ECGs (ρ < 0.01). In future studies, investigators should determine which types of music help stabilize the heart rate during driving.

A Preliminary Study on Shore Protection from Erosion around Seoguipo Coastal Waters (서귀포 연안해역의 침식대책 수립을 위한 기초연구)

  • Jeon Min-Su;Lee Joong-Woo;Lee Hak-Seung;Hwan Ho-Dong;An Do-Kyung
    • Journal of Navigation and Port Research
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    • v.29 no.6 s.102
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    • pp.537-545
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    • 2005
  • Traditionally Jeju island has a mild oceanic climate throughout the year and famous as worldwide resort area bemuse of its pure natural environment and dramatic coastal scenery. But unpredicted coastal erosion problem, mused by variation of environmental conditions from construction of coastal structure and renovation of the existing ports, has raised its head above the water, and is becoming serious these days just like other coastal area in Korea. The phenomena happen here along the seaside of southern part of the island show that severe changes in coastal line from erosion and even witnessed the coastal cliff failure. In advanced countries, coastal engineers and researchers have studied deeply about this kind of problem for a long time. However, as it is not sot active in Korea and lack of research data, there exists difficulties on building protection methods and thoughtless constructions might make it more complicated and fatal to the coastal environment. In this study, we investigated some case studies of other countries and intended to induce and propose some integral protection methods for coastline erosion, considering environmentally sound and water friendly way of development such as artificial reef, floating breakwater, and double cellblock breakwater. Finally, we made analysis on the proposed methods with numerical model test and evaluation on the feasibility of each method.

A Reduction Effect in Noise Reflection by Different Shapes of Soundproofing-panel (도로소음원에 대한 방음패널 형상별 반사소음 저감효과)

  • Kim, Ilho;Park, Taeho;Chang, Seoil;Lee, Haein
    • Journal of Korean Society of Environmental Engineers
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    • v.37 no.2
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    • pp.120-125
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    • 2015
  • With rapid urbanization, the volume of traffic in urban area has been significantly increased. This in turn led to problem which can be described as Road Traffic Noise. Currently, to alleviate the road traffic noise damage, a demand for installation of soundproofing walls is rising. Among different shapes of soundproof walls being installed, the reflection-type acoustical insulation panel is highly drawing attentions of residents due to the fact that it does not obstruct their field of vision in contrast with the opaque acoustical insulation panel. On the other hand, improving the soundproofing wall of the reflection-type acoustical insulation barrier panel needs to be focused on since it has a possibility to cause a secondary damage by reflected sounds. Therefore, in this research, study has been carried out to improve the forms in order to minimize travelling of reflected sounds through changing the frontal surface shape and geometrical shape of the reflection-type soundproofing panel. A result from comparison between the normal reflection-type soundproofing panel and the improved soundproofing panel, with reduction effects in the noise reflection, showed that the curved type of soundproofing panel has an impact on reducing the noise up to 1.5 dB. Furthermore, from the research conducted, it appears that the increase and decrease in the reflected sounds can be changeable depending on various design factors. Thus, it turns out that the study shows a potential possibility to develop a reduction technology of the reflected sounds pertaining to overall condition on the soundproofing walls.

Analysis of Field Librarians' Employment Needs and Human Resource Development in Librarianship (사서직 고용현황 및 인력개발에 대한 현장사서 요구 분석)

  • Noh, Younghee;Ahn, In-Ja;Oh, Se-Hoon
    • Journal of the Korean Society for information Management
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    • v.30 no.4
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    • pp.61-91
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    • 2013
  • In order to achieve effective human resource development in LIS fields, it is essential to have strategies to nurture and utilize those human resources, in relation to supply and demand as well a sound legal foundation supporting those strategies. Such strategies and legal foundation can only be developed from a complete knowledge of the current status of human resources in the LIS and related industries. This study, therefore, conducted research on the basic employment status, employment environment, and an overall analysis of related issues, in order to address policy implications on the effectiveness of human resource development in the LIS field. This research included the current status of policy environments that involve social environment, and related institutions and laws, and human resources developments as well as the current requirements of librarians in the field, based on a demand survey of LIS employment. It was found that first, there are three distinguishable factors in LIS employment: a feminization of librarianship, an increase in temporary posts, and a high entering ratio into the library workplace. Second, while there were only little differences in the given tasks between full-time and temporary employees, the differences in salary and welfare were considerably larger. Third, field requirements for librarian education included a mentoring system with field experts, short-term internships, and librarian apprenticeships, while job requirements included internship or apprenticeship, language skills, various license acquisition, and career management. Fourth, librarians with licenses for related organizations held 20% more librarian licenses overall.