• 유기물자원화
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• 제24권1호
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• pp.41-49
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• 2016

본 연구는 음식물류 폐기물 공공 자원화 시설 운영의 문제점과 제도 개선방안을 위하여 실시하였다. 기존 음식물류 폐기물 공공자원화 시설에 대한 실태조사를 통해 운영에 따른 문제를 분석하였으며, 이를 위하여 음식물류 폐기물의 발생량 및 자원화 현황, 공공 및 민간 자원화시설 현황, 전국의 주요 음식물류 폐기물 공공 자원화 시설의 실제 운영과정에서 나타난 문제점을 분석한 결과는 다음과 같다: 현재 국내 음식물류 폐기물의 분리 수거량은 약 97%인 것으로 나타났다. 그리고 대부분의 공공 자원화시설은 음식물류 폐기물의 자원화가 아닌 단순처리에 급급한 것으로 나타났으며 경제성도 없는 것으로 분석되었다. 특히, 바이오가스시설 대부분은 실시설계와는 달리 가스 생산량 및 수요량이 전혀 맞지 않는 것으로 나타났다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.539-546
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• 1996

The physical condition of rapeseed delivered to fat industry plants plays a significant role in the formation of the qualitative features of the raw material for oil production and, consequently , of the oil itself. Rapeseed is stored in silos , frequently for months, before it is subjected to processing. During the long storage, the conditions of the seed cover is very important, as the seed cover provides natural protection of the seed against the effect of the environment. Seeds with damaged seed cover are more easily affected by mildew, and the rate of chemical processes. Deteriorating the quality of oil contained in the cotyledons is faster in such seeds. Cracked seed covers facilitates also the growth and development of microorgaism. So as rapeseed damage occurring inthe course of harvest and the post-harvest processing have a negative effect of the quality and quantity of oil the sees contain. The study presented here was aimed at examining the typical process of purcha ing and handling of rapeseed in fat industry plants, in the aspect of the occurrence of mechanical damage to the seeds. Special attention was paid to the condition of rapeseed immediately after combine harvesting : next , the successive stages of technological handling of the seed were examined. observing the operation parameters of the particular machinery and equipment in order to identify those operations which caused deterioration in the quality of the material (sees). Seed samples were taken successively from the following the hopper, prior to cleaning , after cleaning , prior to drying , after drying, from dry rape silo. The total level of damage increased through the handling. The content of unusable contaminants had the tendency to decrease in the successive operations. though the actual values still exceeded levels permitted by standards. The study allow to indicate the operation fo postharvest technological process, which cause the most seed damage as well as gave quantita ive description of the losses occurred.

• 농촌계획
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• 제17권3호
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• pp.67-80
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• 2011

This study was conducted to understand the distribution characteristics of old tree (protected tree) and propose the effective management plan for old tree to make hold a sustained function as natural and cultural resources in rural area. We surveyed 96 old trees at 69 farm villages in Yaesan-gun, South Chungcheong Province. The species of tree was investigated with Zelkova serrata, Ginkgo biloba, Quercus acutissima, Pinus densiflora, Celtis sinensis, and Juniperus cbinensis order. Most of them located at the inside (43.6%) and the entrance (35.1%) of a village, and at mountain slope (31.9%) and alluvial plain (25.3%) in terms of distribution topography. The existing place of pollution source was investigated with 61%, and the pollution sources were blocks, construction materials, cement packings, farm machines and living garbage. The place where the rates of bare ground were more than 50% for the root region of a protection tree was 63%. The tree surgical operation was investigated in 37.5% of protection trees, and 12.5% of protection trees were investigated with a tree surgical operation being immediately. The average score for health condition of old tree at study sites was 18.6 points. A monitoring class was divided by public monitor 59.3%, main monitor 38.5%, and dead tree 2.2% on the basis of that information. Hereafter, we will conduct to promote the management guideline and develope culture contents through additional investigation.

• 전기학회논문지
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• 제66권10호
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• pp.1466-1473
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• 2017

Generally, electrical torque in synchronous generator is balanced with the rotor mechanical torque under steady-state condition. Thus, the synchronous generator rotor rotates at constant speed. However, under fault condition, the electrical torque output is suddenly decreased and the sum of both torques does not remain constant. If the mechanical torque is not decreased at the same time, the generator rotor would accelerate. Therefore, this accelerating generator rotates at different speeds with respect to other generators in the power system. This phenomena is called as Out-of-Step (OOS). In this paper, we presented a certain two-step type quadrilateral OOS relay setting, which is applicable in actual field, and examined the validity of its setting value with OOS simulation conditions due to delayed fault clearing in transmission line. In order to conduct the study of OOS relay characteristics, we checked the impedance locus and generator output characteristics under the various delayed fault clearing conditions. Moreover, we proposed a countermeasure for avoiding the misoperation of OOS relay during the stable swing by modifying the setting values.

• Nuclear Engineering and Technology
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• 제56권6호
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• pp.2220-2238
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• 2024

As a typical active equipment, pump machinery is widely used in nuclear power plants. Although the mechanism of pump machinery in nuclear power plants is similar to that of conventional pumps, the safety and reliability requirements of nuclear pumps are higher in complex operating environments. Once there is significant performance degradation or failure, it may cause huge security risks and economic losses. There are many pumps mechanical parameters, and it is very important to explore the correlation between multi-dimensional variables and condition. Therefore, a condition monitoring model based on Deep Denoising Autoencoder (DDAE) is constructed in this paper. This model not only ensures low false positive rate, but also realizes early abnormal monitoring and location. In order to alleviate the influence of parameter time-varying effect on the model in long-term monitoring, this paper combined equidistant sampling strategy and DDAE model to enhance the monitoring efficiency. By using the simulation data of reactor coolant pump and the actual centrifugal pump data, the monitoring and positioning capabilities of the proposed scheme under normal and abnormal conditions were verified. This paper has important reference significance for improving the intelligent operation and maintenance efficiency of nuclear power plants.

• 대한공업교육학회지
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• 제32권2호
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• pp.69-86
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• 2007

이 연구는 중소기업분야 특성화 전문계 고등학교의 운영실태를 조사, 분석하기 위해서 수행된 것으로, 중소기업분야 특성화 전문계 고등학교로 선정된 29개교의 특성화 담당교사와 면담 및 전화 인터뷰를 통하여 자료를 수집, 분석하였다. 연구결과 첫째, 29개교 중소기업분야 특성화 전문계 고등학교는 제조업기반기술과 제조업 지원업종으로 특성화하고 있으나 제조업 기반기술 분야가 79%로 큰 비중을 차지하고 있었다. 둘째, 신입생 지원 현황은 2006, 2007년 모두 1.01의 경쟁률로 비교적 낮게 나타났다. 셋째, 전체교원 중 여교사가 차지하는 비율은 32%였으나 보직교사이상에서는 14%로 매우 낮았다. 넷째, 실험 실습실은 확보율은 94%로 비교적 안정적이었고, 기자재 보유율은 76.4%로 조금 낮았다. 마지막으로 다른 사업 추진 현황을 분석한 결과 72.4%의 학교가 다른 사업과 병행하고 있었다. 따라서 중소기업분야 특성화 전문계 고등학교 육성 방향은 다른 사업과의 차별성에 중점을 두고 이루어져야 한다.

• 한국재난정보학회 논문집
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• 제17권2호
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• pp.391-402
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• 2021

연구목적: 안전인증 생태계 주체별 의견 유형화를 통하여 제도 운영상의 취약점을 확인하고 미래 변동성에 대하여 안전인증제도가 빠른 회복력을 가질 수 있도록 개선방안을 제시하고자 한다. 연구방법: 문헌조사 및 자료 분석을 통해 국내·외 유사 안전인증 및 관련 사례와 국제 기준 및 국가 표준 현황 등을 확인하였으며, 안전인증 생태계의 이해관계자별로 실태조사를 실시하고 문제점 유형화 및 개선방안을 수립하였다. 연구결과: 안전인증대상기계등을 제조 또는 수입하거나 사용하는 사업장을 대상으로 안전인증 대상품에 대한 품질 만족도, 개발제조 및 사용과정에서의 장애요인, 안전인증 관련 개선사항 등 제도전반에 걸친 실태조사를 실시하고 제도 운영상의 문제점 및 취약점을 발굴 및 범주화하여 개선방향 수립 및 작동성 향상을 위한 세부 추진과제를 도출하였다. 결론: 안전인증제도의 선진화·국제화를 위해서는 본 연구를 통하여 도출된 세부 추진과제를 효율적으로 수행하여야 할 것이며, 더불어 안전인증 생태계의 변동성에 대한 회복력 강화를 위해서는 주체별 상호 관계 개선을 통하여 선순환 구조의 운영시스템 구축이 중요하다고 판단된다.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1317-1325
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• 2018

A generator-grid coupling calculation model is established to study the leading-phase operational capability of a 770 MW jumbo hydro-generator in a Chinese ultra-mega hydropower station. The static and dynamic stability of the generator are analyzed and calculated to obtain stability limits under leading-phase operating conditions. Three-dimensional (3D) time-varying nonlinear moving electromagnetic and temperature field models of the generator end-region are also established and used to determine the magnetic field, loss, and temperature of the end-region under the leading-phase operating condition. The simulation results agree with data measured from the actual 770 MW hydro-generator. This paper provides reliable reference data for the leading-phase operation of a jumbo hydro-generator, which will help to improve in the design and manufacture of future hydro-generators.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1370-1378
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• 2007

고속철도 교량은 고속주행 열차의 차축 주기하중 효과와 교량 고유의 동적특성에 의한 동적 증폭 효과로 인하여 구조물의 안전성에 영향을 받는다. 그리고 교량의 과도한 변형으로 인하여 차륜과 레일의 접촉력 감소, 궤도틀림 등의 윤중 변동이 일어나 열차의 주행안전성 및 승차감을 저해할 수 있다. 이러한 궤도 안전성을 확보하기 위하여 동적거동에 대한 교량상판수준의 수직가속도 제한, 차륜-레일간의 접촉과 열차주행 안전성 확보를 위한 상판 면틀림 제한, 단부 회전각 변위 제한, 차량하중에 의한 교량의 수직 처짐 제한을 반드시 만족시켜야 하며, 필수적으로 공진에 대한 검토도 이루어져야 한다. 신설되는 호남고속철도에서는 기존의 경부고속철도와 다른 콘크리트 도상을 적용하고, 궤도간격, 설계열차하중 등이 변경되어 적용되므로 새로운 동적안정성 요구조건을 적용하게 된다. 본 연구에서는 콘크리트교량에 비해 진동특성이 취약한 것으로 알려진 강합성 거더 고속철도 교량의 동적거동 분석을 수행하였다.

• 한국태양에너지학회 논문집
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• 제35권1호
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• pp.45-52
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• 2015

The government is fostering a renewable energy industry as an alternative to handle the energy crisis. Among the renewable energy systems available, geothermal energy is being highlighted as being highly efficient and safely operable without the effect of outdoor air. Accordingly, a study on the geothermal heat pump is in progress in various worldwide perspective. However, Geothermal energy is only in charge of part load of the building due to the high initial installation cost in korea. Moreover, its efficiency is reduced due to the use of independent existing heat sources. In this study, after selecting the building containing the actual installed geothermal heat pump, the use of excellent geothermal heat pump systems was maximized in terms of the energy efficiency. The objective of this study is to show the operation method of geothermal heat pump system to improve energy efficiency through the TRNSYS simulation. This paper proposed operation methods of geothermal heat pump control according to outdoor air temperature. The result of this study is that existing operation method had some problems and if offered improvement is applied to real condition, energy consumption would be decreased.