• Title, Summary, Keyword: level of contribution

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Noise Contribution Analysis and Noise reduction of a Diesel Engine Fork-lift Truck (디젤 엔진 지게차의 소음원별 기여도 분석과 실내소음 저감)

  • Lee, J.K.;Cho, Y.H.;Kim, G.H.;Park, S.T.;Kim, N.I.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1473-1478
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    • 2000
  • Severe fork-lift truck noise is annoying to an operator as well as one of the noise pollution elements. This paper presents the noise contribution analysis of a cabin type fork-lift truck to identify the major sources and its usage to reduce the interior noise level. The methodologies for this work are sound field analysis, sound intensity test, insertion loss test of duct system and etc. An effective method to suppress interior noise level of fork-lift truck and design guides are suggested.

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Comparison on the Consciousness Level of the Social Contribution and Career Awareness between Elementary Gifted Students and General Students (초등 과학영재와 일반학생의 진로인식과 사회적 기여의식 수준 비교)

  • Lee, Hwa-Jeong;Kwon, Chi-Soon
    • Journal of the Korean Society of Earth Science Education
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    • v.7 no.1
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    • pp.110-118
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    • 2014
  • The purpose of this study was to compare the career awareness and social contribution consciousness between the elementary science gifted students and the general students. For this, survey was taken by 201 gifted students and 216 general students. Methods used are Cronbach alpha, frequency, percentage, independent t-test and Pearson's correlation coefficient. The results are as follows : 1. The gifted students have higher career awareness than the general students. The gifted students recognize their own interests, aptitudes and talents which they are concerned. 2. The gifted students have higher social contribution consciousness than the another. This shows that the gifted students have desire to be respected and positive view of social contribution. 3. There is a positive correlation between career awareness and the social contribution consciousness. According to the past studies, students' household economic status affect their view or grade which they get.. Based on these results, we suggest that a development of educational program for career awareness and social contribution consciousness which can improve gifted students' social responsibility consciousness is necessary.

A Study on Transfer Characteristics of Vehicle Air-conditioner Booming noise (차량용 에어컨 부밍 소음의 전달 특성에 관한 연구)

  • Lim, Seung Taek;Joo, Kyung Hoon;Ahn, Hew Nam;Park, Young Duk;Kang, Yean Jun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.476-481
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    • 2013
  • Transfer path analysis(TPA) and operational deflection shape(ODS) have been widely utilized to analyze the characteristics of noise. TPA enables to decompose a noise into air-borne and structure-borne noises then estimate the path contribution of noise. ODS enables to analyze a moving shape and direction of interest components at a particular frequency. In this paper, TPA and ODS are applied to transfer paths of air-conditioner booming noise in a vehicle to reduce noise level, then a fixture is mounted it's path for distributing the high portion path contribution to the low portion path contribution. Through this experiment, the reduction of sound pressure level in air-conditioner booming noise is observed. Thereafter, TPA is again employed to verify the results of contribution.

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A Study on Contribution Analysis using Operational Transfer Path Analysis based on the Correlation between Subjective Evaluation and Zwicker's Sound Quality Index for Sound Quality of Forklifts (지게차의 주관적 음질평가와 Zwicker 음질지수의 상관관계 및 전달경로분석법(OTPA)을 활용한 음질 기여도 분석)

  • Kim, Beom Soo;Yang, Soon Yong
    • Journal of Drive and Control
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    • v.13 no.2
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    • pp.19-25
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    • 2016
  • Recently, drivers have begun to regard comfort in the cabin as one of the most important factors in construction equipment like forklifts. Accordingly, it has become more important to design a forklift cabin with a better sound quality as well as lower sound level, which can make a driver more comfortable. In this paper, the correlation between subjective evaluation and Zwicker's sound quality index was analyzed through a blind test by a few workers in forklifts and other construction equipment in several countries. Correlation analysis showed that Loudness and Sharpness were ranked in sequence, and tendencies were different from country to country. Also, contribution analysis for Loudness and Sharpness using operational transfer path analysis (OTPA), which is widely used in the field of noise, vibration, and harshness (NVH), was performed. However, Loudness and Sharpness cannot be used with OTPA directly because there are no linear relationships between the sources and receivers. In this paper, both are calculated by applying the DIN 45631 method with a contribution rate (%) of 1/3 Octave Sound Pressure Level by OTPA method in addition to considering spectral masking.

Reducing the Interior Noise of the Korean High-speed Train Using Geometric Acoustic Method (기하음향 기법을 적용한 한국형 고속철도 실내소음 저감 방안)

  • Kim, Kwan-Ju;Park, Jin-Kyu
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.6
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    • pp.431-436
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    • 2002
  • The interior sound pressure level of the Korean high-speed train(KHST) is predicted by geometrical acoustic method. For the Purpose of assuring the prediction of Interior noise of KHST by the geometrical acoustic scheme, calculated sound level values of the Korean train express(KTX) by Identical geometrical method are compared with measured values of KTX prototype vehicle by experiment. Contribution of individual sound source of KHST vehicle Into the interior response positions is calculated and sound sources are classified in influential order. Hence, it is reasonable approach to reduce sound power of most contributing noise source first. Sensitivity of the interior response position's sound pressure level (SPL) with respect to train wall sections' transmission loss are carried on and acoustically sensitive spot is identified, for example window area for passenger cabin case. Those contribution and sensitivity analysis results are suggested to design quieter train efficiently.

Contribution of Phytoplankton and Zooplankton to Total Organic Carbon (TOC) in the Reservoir-river-Seonakdong River, Busan (서낙동강에서 동·식물플랑크톤의 총유기탄소 기여율 변동 분석)

  • Lee, You-Jung
    • Journal of Environmental Science International
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    • v.29 no.7
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    • pp.691-702
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    • 2020
  • Carbon biomass of plankton community, Total Organic Carbon (TOC) and Chlorophyll a (chl.a) concentration were examined in the SeoNakdong river from January to December in 2014, to assess composition of phyto- and zoo-plankton variation, to certify the correlation between chl.a and TOC and to determine the level of contribution of plankton carbon content to TOC in the reservoir-river ecosystem. The correlation level between TOC and chl.a was low in the year 2014 but exceptionally was highly correlated only during the period with cyanobacterial bloom. The high level of contribution of plankton carbon content to TOC was attributed to cyanobacterial carbon biomass from May to November and to Cladocera carbon biomass from March to May, November and December despite of its low abundance. These results suggest that there were inter-relationships between phytoplankton, zooplankton and TOC and also subtle consistency of their properties through the year. These patterns should be discussed in relation to the physiochemical and biological characteristics of the environment, as well as to allochthonous organic matters from non-point pollution sources.

Determinants of Urban Growth in Korea (시.공입체모형에 의한 한국의 도시성장 결정요인 분석)

  • 박연수
    • Journal of the Korean Regional Science Association
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    • v.13 no.2
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    • pp.93-118
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    • 1997
  • Main findings of this study are as follows. Time-space model of Korea for urban growth model is established. The variables of space model resulted in job and education, which both are significant at 0.01 level and positive. The effect of job and education on the urban growth are 0.76 and 0.29 respectively in average. the determinants for deciding the influences for job variable are income variable and price-level variable. Income variable contributes 68.66% and the direction is negative while contribution of price-level variable is 29.90% and the direction is positive. The determinants for education variable are income, unemployment and wage difference between university graduates and high school graduates. The contribution and the high school graduates. The contribution and the direction of each variable for education variable are 63.6% and positive for the unemployment variable, 15.99% and negative for the income variable and 13.75% and positive for the wage difference variable. This study in different from previous works in three ways. The first is to establish the time-space model which could consider the time and space factor simultaneously. The second is to build data bases which contain the data of almost every city and every year in Korea during the objective period, which make the analysis continuous. The third is that the general analytic framework for the study is macrosocial one rather than a behavioral one, which means the unit of analysis is the metropolitan community and each city occupies population actively through it's potential power such as jobs, education and so on rather than a city population is the passive result of migration.

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Estimation of Source Contribution by Air Pollutant Type (Point, Area, Line) over Seoul Metropolitan Area (수도권지역에서 오염원별 대기오염농도 기여도 평가)

  • Park, Il-Soo;Lee, Suk-Jo;Kim, Jong-Choon;Kim, Sang-Kyun;Lee, Dong-Won;Yoo, Chul;Lee, Jae-Bum;Song, Hyung-Do;Lee, Jung-Young;Kim, Ji-Hyun
    • Journal of Korean Society for Atmospheric Environment
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    • v.21 no.5
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    • pp.495-505
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    • 2005
  • This study is to estimate source contribution by air pollutantion types (point, area, line) over Seoul metropolitan area. The Air Pollution Model (TAPM) and the highly resolved anthropogenic and biogenic gridded emissions ($1km{\times}1km$) were applied to simulate $SO_2,\;NO_2,\;O_3\;and\;PM_{10}$ concentrations by seasons and contribution was estimated by their source types (point, area, line). The results showed that the simulated concentrations of secondary pollutant agreed well with observed values with an index of agreement (IOA) over 0.4, whereas IOAs over 0.3 were observed for most primary pollutants. The contributions of each source types by seasons were similar. The point source contribution was the highest for $SO_2$ at medium level ranged from $55.1\%\;to\;61.5\%$. But the contribution from area source during for the spring and summer increased as the concentration level increased. The line source contribution was the highest for $NO_2$ at all levels ranged from $68.3\%\;to\;93.1\%$. The results indicate that $SO_2$ emissions should be mainly controlled from point source, as well as area source at higher level concentration. Also, $NO_2\;and\;PM_{10}$ to from line source should be controlled.

Analysis of Noise Contribution using Frequency Response Function and Measurements of Noise Distribution for Railway Interior Noise (주파수 응답 함수를 이용한 철도차량 실내소음 기여도 분석 및 분포도 측정)

  • 김재철;유원희
    • Journal of KSNVE
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    • v.9 no.5
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    • pp.949-954
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    • 1999
  • Speed-up and mass reduction of railway vehicle usually causes increased of the interior noise. One of the best ways to control the interior noise is to identify the noise level radiated from each of parts in the cabin. In this paper, we describe the method to estimate the interior noise nad evaluate the noise contribution to each of parts. This method is based that the sound pressure can be calculated by using the frequency response function and acceleration. According to analysis of the noise contribution, we validated that the noise radiated from the floor is the higher in the cabin. We also measured the noise distribution for the side and floor by using the microphone array in order to analyze the effect of the noise flowing into the cabin from the outdoors. Finally, we presented the plan of the interior noise reduction based on the noise levels radiated from each of parts.

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A Study on the Economic Contribution of IT Labor (IT 근로자의 부가가치 창출에 대한 기여도 분석)

  • Lee, Kang-Bae
    • The Journal of Information Systems
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    • v.20 no.3
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    • pp.187-207
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    • 2011
  • As the IT labor captures an increasing proportion of the total labor, it is important to analyze the contribution of IT labor to national economy. Although there has been abundant research about the effect of IT investments, it is difficult to find a research about IT labor's economic contribution. Most prior studies on the effect of IT investment have focused on the effect of IT capital investment. This paper empirically explores whether and how IT labor makes contribution to Korean economy. And also this paper examines the economic contribution of IT experts and semi-experts in Korean industries over the 2000 to 2007 period, using production function framework and panel data set for 24 industries constructed from 'Input-Output table' and 'Research on Wage Structure Survey'. Based on the full sample of 120 observations, this study finds that a 1% increase in IT labor wage is associated with 0.042190% increase in added value. In the case of non-manufacturing industries on the sample of 50 observations, this study finds that a 1% increase in IT labor wage is associated with 0.074908% increase in added value. And in the case of IT experts (separated from IT semi-experts), this study finds that a 1% increase in IT expert's labor wage is associated with 0.013957% increase in added value of all industry. This study provides implication for policy makers and managers. The results suggests that non-manufacturing industries can capture further benefits by increasing investment in IT labor. Building on this study, future research should examine the impact of IT labor at a more detailed industry level and the firm level.