• 한국주거학회논문집
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• 제19권5호
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• pp.85-92
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• 2008

The aim of this research is to develop the sentiment indicators of housing welfare for evaluating housing welfare policies conducted by the Korean government. The methods of this research are used by analysis of related documents, FGI (Focus Group Interview), and survey. The survey was made by experts and consumers. To analyze the survey, this research also uses confirmatory factor analysis by SPSS (Statistical Package for the Social Science) program, AHP (Analytical Hierarchy Process) by Expert Choice program, frequency, average, percentages, Factor analysis etc. As a result of this research, selected housing welfare indicators are settled as follows: In the housing welfare aspect, 11 indicators in the department of 'Housing Satisfaction' and 11 indicators in the department of 'Community Satisfaction' (22 in total) are suggested. The indicators are 1) Water Supply and Distribution Equipment 2) Heating equipment 3) the size of the exclusive residential area 4) the number of rooms 5) Ventilation and Lighting 6) Sound Insulation (Indoor Noise) 7) Air Pollution/Odor 8) House Deposit 9) Rent Paid 10) Maintenance (Dwelling) Cost 11) The length of Occupation 12) Proximity to Welfare Facilities 13) Educational Environment 14) Convenience of Facilities (shops, hospitals etc.) 15) Convenience of Transportation and Commuting 16) Distance from Workplace 17) Landscape and Green Space (Tree, Flowers, Grass etc.) 18) Vandalism (Destruction Behavior, graffiti etc.) 19) Privacy 20) Noise in Public Places (Drinking, Loudly Talking etc.) 21) Safety from Crime 22) Safety from a Disaster. As of 2007, the housing welfare sentiment index is measured by the survey of 1,000 inhabitants in the public housing, which shows 3.51.

• 한국소음진동공학회논문집
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• 제23권5호
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• pp.385-393
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• 2013

In this paper, the mechanism identification and the avoidance measures on the phenomena of transient acoustic vibration amplified at the water-supply piping system to regulate the steam temperature of the boiler reheater in 500MW class supercritical power plant are presented. The pressure pulsation waves induced by the impeller passing of two feed-water pumps with five blades are coincident with the local acoustic modes of boiler reheater water-supply piping system. There are the phenomena amplified at the peaks of 5X, 10X, 15X and 20X in spectrums of piping vibration, sound pressure, and the feed-water's pressure pulsation waves. The shut-off device is installed in the piping system for the interception of pressure pulsation waves transmitted from two feed-water pumps and the modified design change of the piping layout is applied for the acoustic resonance avoidance. The acoustic natural frequencies are separated from the harmonics of pressure pulsation waves induced by the pump impellers passing through the design change of the span length. The acoustic vibration is gone by resonance avoidance measures. As a result, more than 20 dBA reduction is achieved from 100 dBA to 80 dBA.

• 농촌계획
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• 제9권2호
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• pp.13-17
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• 2003

A purpose of this study is to develop practical indexes for improving a village environment in Kyongbuk, Korea. From a questionnaire survey of the public employees (71 persons) who take charge of the environment in Kyongbuk province, the indexes were produced and the contents of questionnaire consisted of preferential and supplementary indexes to apply. The preferential indexes which apply to an agricultural village and a stock raising village are environmental sanitation facilities, a hygienic check of livestock and a purge of livestock shed's surroundings. In case of mountainous village, and natural-ecological village the preferential indexes are habitat reservation for wildlife, poaching prohibition (monitoring for it), and food supplement for livestock. To the traditional-cultural village, prevention of noise pollution, environmental sanitation facilities, and a monitoring or water quality change are the prior indexes in order. For the village near city and the industrial village the preferential indexes are patrol removing of garbage, pollution index planting and monitoring for noise pollution. For a fishing village and a village fronting waterside excess uses of agricultural chemicals, monitoring for a water quality change, and realignment of green house with vinyl and warehouse. In conclusion the research presents the practical and preferential index for residents to improve their environment in accordance with village settings and suggests guidelines for further research.

• 한국조경학회지
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• 제37권4호
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• pp.42-51
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• 2009

본 연구는 경상북도에 소재하는 초등학교의 학교숲 현황을 조사하고, 주 이용자인 학생들을 대상으로 만족도 설문을 실시하여 만족유형에 따른 학교숲 조성방향을 제시하였다. 연구 결과를 요약하면 학교숲의 만족도는 수목 많음 항목이 가장 높았고, 소음 감소 항목이 가장 낮게 나타났다. 15개의 항목별 만족도를 이용하여 요인분석을 실시한 결과 3개 요인이 추출되었으며 각각 환경적 기능, 교육 휴게 기능, 생태적 기능으로 명명하였다. 다음으로 요인 점수를 이용하여 학생들을 4개의 군집으로 유형화하였다. 그 결과, 군집 I은 환경적 기능, 군집 III은 교육 휴게 기능, 군집 IV는 생태적 기능의 만족도가 높은 것으로 분석되었으며, 군집 II는 3개의 기능에 대한 만족도가 모두 낮은 것으로 나타났다. 학생들의 만족유형에 따라 학교별 특성을 살펴본 결과, 군집 II에 속하는 학생들이 적고, 타군집의 분포가 비슷한 학교일수록 전체 만족도가 높은 것으로 분석되었다. 이러한 학교의 경우 운동장의 많은 부분을 식재공간으로 활용하여 학교숲 면적 및 비율이 타학교에 비해 크게 나타났으며, 체험 및 교육 프로그램을 통해 학생들의 참여를 유도하고 있는 것으로 분석되었다. 따라서, 학교숲을 조성할 경우 학교숲의 양적인 증가와 더불어 다양한 체험 및 교육 프로그램 등을 도입하여 환경적, 교육 휴게 및 생태적 기능 등 학생들의 만족요인을 고려해야 하며, 기존 화단에 수목을 추가하는 방식보다는 학교숲을 이용할 수 있는 공원형 방식으로 조성해야 할 것으로 판단된다.

• 환경영향평가
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• 제32권1호
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• pp.1-14
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• 2023

백로번식지 주변 개발사업을 진행할 때 환경영향평가 단계에서 갈등을 사전에 예방할 수 있도록 중점평가항목 선정과 저감방안을 제시하여 지속가능한 공존의 방안을 강구하고자 한다. 중점평가항목으로 백로번식지 보전을 위한 동·식물상 항목, 백로번식지로 인한 악취와 소음의 영향을 평가할 수 있는 악취와 소음 항목을 선정한다. 평가항목의 평가방안은 첫째, 동·식물상 항목에서 조사범위는 법정보호종 위주로 국한하지 말고 주요 종 번식지와 철새도래지에 해당하는 백로번식지와 취식지까지 포함하여 조사하고, 번식지와 취식지 면적감소에 따른 보전방안을 세운다. 둘째, 악취 항목에서 조사시기는 6월말에서 7월말까지 악취발생량이 최고인 시점을 포함한다. 악취 평가기준은 농도규제인 복합악취 배출허용기준과 사람이 느끼는 악취농도는 2~5OU/m³, 빈도는 2% 이하로 한다. 셋째, 소음 항목에서 조사시기는 백로류와 어린 새들의 소리가 합해져서 소음 발생이 최대가 되는 시점을 포함하여 5월부터 8월까지 매달 소음을 측정한다. 여름철새인 백로류의 소음은 일정 기간에만 발생하기 때문에 방음벽 설치 등 인공적인 구조물 설치로 소음을 저감하기 보다는 이격거리확보, 완충녹지, 마운딩 조성 등의 방법으로 저감대책을 세운다. 기존 백로번식지가 개체군의 적정한 밀도를 유지하면서 개체군이 다른 곳으로 이동하지 않기 위해서는 영소목 관리와 취식지의 양과 질을 안정적으로 유지해주는 것이 선행되어야 한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1300-1305
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• 2011

철도 관련 사업 및 연구개발시 수행하는 타당성조사에서 환경적 파급효과 산정의 중요성이 증대되고 있다. 그러나 현재의 투자평가시 고려되는 평가항목은 이동성에 기반한 효율성 위주의 항목으로 구성되어 있다. 현재 시행되는 예비타당성조사 및 타당성 평가의 주요 계량화 항목을 보면 차량운행 비용절감 편익, 통행시간 절감편익, 교통사고 감소편익, 환경비용 절감편익으로 분류된다. 현재의 환경비용 절감편익은 단순히 오염물질 별 원단위에 따른 산정에 그치고 있어 최근녹색성장 및 지속가능한 교통체계의 패러다임에 맞는 사회경제적 평가항목의 도입이 필요하다. 국내의 타당성 평가내용을 보면 계량화가 힘든 부분은 정책적 분석에서 고려되나 참고사항에 그치고 있어 계량화가 가능한 방법론의 개발이 필요하다. 대표적인 환경편익인 소음, 공간영향과 대기오염에 관한 평가체계의 정립이 필요한 시점이다. 따라서 본 연구는 기존 국내외 환경비용절감편익 연구 내용분석을 바탕으로 지속가능한 교통체계 및 녹색교통의 패러다임에 적절한 평가항목에 관한 연구방향을 제시하고자 한다.

• Journal of Communications and Networks
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• 제16권1호
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• pp.36-44
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• 2014

Exploiting the energy-delay tradeoff for energy saving is critical for developing green wireless communication systems. In this paper, we investigate the delay-constrained energy-efficient packet transmission. We aim to minimize the energy consumption of multiple randomly arrived packets in an additive white Gaussian noise channel subject to individual packet delay constraints, by taking into account the practical on-off circuit power consumption at the transmitter. First, we consider the offline case, by assuming that the full packet arrival information is known a priori at the transmitter, and formulate the energy minimization problem as a non-convex optimization problem. By exploiting the specific problem structure, we propose an efficient scheduling algorithm to obtain the globally optimal solution. It is shown that the optimal solution consists of two types of scheduling intervals, namely "selected-off" and "always-on" intervals, which correspond to bits-per-joule energy efficiency maximization and "lazy scheduling" rate allocation, respectively. Next, we consider the practical online case where only causal packet arrival information is available. Inspired by the optimal offline solution, we propose a new online scheme. It is shown by simulations that the proposed online scheme has a comparable performance with the optimal offline one and outperforms the design without considering on-off circuit power as well as the other heuristically designed online schemes.

• Advances in aircraft and spacecraft science
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• 제4권6호
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• pp.651-677
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• 2017

For the past ten years' efforts have been made to introduce environmentally-friendly "green" electric-taxi and maneuvering airplane systems. The stated purpose of e-taxi systems is to reduce the taxiing fuel expenses, expedite pushback procedures, reduce gate congestion, reduce ground crew involvement, and reduce noise and air pollution levels at large airports. Airplane-based autonomous traction electric motors receive power from airplane's APU(s) possibly supplemented by onboard batteries. Using additional battery energy storages ads significant inert weight. Systems utilizing nose-gear traction alone are often traction-limited posing serious dispatch problems that could disrupt airport operations. Existing APU capacities are insufficient to deliver power for tractive taxiing while also providing for power off-takes. In order to perform comparative and objective analysis of taxi tractive requirements a "standard" taxiing cycle has been proposed. An analysis of reasonably expected tractive resistances has to account for steepest taxiway and runway slopes, taxiing into strong headwind, minimum required coasting speeds, and minimum acceptable acceleration requirements due to runway incursions issues. A mathematical model of tractive resistances was developed and was tested using six different production airplanes all at the maximum taxi/ramp weights. The model estimates the tractive force, energy, average and peak power requirements. It has been estimated that required maximum net tractive force should be 10% to 15% of the taxi weight for safe and expeditious airport movements. Hence, airplanes can be dispatched to move independently if the operational tractive taxi coefficient is 0.1 or higher.

• 전기학회논문지P
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• 제66권4호
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• pp.200-205
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• 2017

In this paper, we propose a technique to determine the normal and arc of an alternating current using a mixed filter composed of an average filter and a band-pass filter and a frequency analysis. The proposed method uses the moving average filter of the FIR filter structure for noise removal and the band-pass filter of the IIR filter structure for detecting only specific frequency components after normalizing the measured current signal based on the maximum value. After performing Fast Fourier Transform (FFT) using the band-pass filtered signal, the total energy is calculated using the magnitude component of the frequency, and the arc is detected using the magnitude of the calculated energy. In order to show the validity of the proposed method, we experimented with various data and found that arc and steady state can be easily discriminated by calculating spectral energy. Therefore, it is considered that the proposed method can be applied to arc diagnosis of low voltage electric wire.

• 대기
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• 제18권1호
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• pp.1-14
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• 2008

The cloud amount, one of the basic parameter in atmospheric observation, have been observed by naked eyes of observers, which is affected by the subjective view. In order to ensure reliable and objective observation, a new algorithm to retrieve cloud amount was constructed using true color images composed of red, green and blue (RGB). The true color image is obtained by the Skyview, an all-sky imager taking pictures of sky, at the Science Building of Yonsei University, Seoul for a year in 2006. The principle of distinguishing clear sky from cloudy sky lies in the fact that the spectral characteristics of light scattering is different for air molecules and cloud. The result of Skyview's algorithm showed about 77% agreement between the observed cloud amount and the calculated, for the error range, the difference between calculated and observed cloudiness, within ${\pm}2$. Seasonally, the best accuracy of about 83% was obtained within ${\pm}2$ range in summer when the cloud amounts are higher, thus better signal-to-noise ratio. Furthermore, as the sky turbidity increased, the error also increased because of increased scattering which can explain the large error in spring. The algorithm still need to be improved in classifying sky condition more systematically with other complimentary instruments to discriminate thin cloud from haze to reduce errors in detecting clouds.