• Title/Summary/Keyword: 정적 실

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Flame Propagation Characteristics of Propane-Air Premixed Mixtures (프로판-공기 예혼합기의 화염전파 과정에 관한 연구)

  • Bae, Choong-Sik
    • Journal of the Korean Society of Combustion
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    • v.1 no.2
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    • pp.21-29
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    • 1996
  • Flame propagation characteristics of propane-air mixtures were experimentally investigated in constant-volume combustion chambers. Flame propagation process was observed as a function of mixture strength, initial mixture temperature and initial mixture pressure in quiescent mixtures. A cylindrical combustion chamber and a spherical combustion chamber contain a pair of parallel windows through which optical access into the chamber can be provided. Laser two beam deflection method was adopted to measure the local flame propagation, which gave information on the flame size and flame propagation speed. Pressure development was also measured by a piezoelectric pressure transducer to characterize combustion in quiescent mixtures. Burning velocity was calculated from flame propagation and pressure measurements. The effect of flow on flame propagation was also investigated under flowing mixture conditions. Laser two beam method was found to be feasible in measuring flame propagation of quiescent mixtures. Flame was observed to propagate faster with higher initial mixture temperature and lower initial pressure. Combustion duration was shortened in the highly turbulent flowing mixtures.

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AIS 데이터를 활용한 선박의 항적모니터링 기능구현에 관한 연구

  • Kim, Eun-Gyeong;Jeong, Jung-Sik;Park, Gye-Gak
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2012.10a
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    • pp.138-140
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    • 2012
  • 본 연구에서는 실제 AIS의 정적, 동적 데이터를 수집하여 항계내 통항 선박의 움직임을 파악하였다. 실제 완도항 부근의 직선항로을 통항하는 선박 항적의 분석하여 불규칙적인 선박의 특성을 알아보고자 하였다. 기존의 과거 누적 데이터의 퍼지이론을 활용한 이상 거동의 선박식별 시스템은 전문가 시스템에 의존하여 항적의 비정상성을 판단하므로 항로의 특성에 따른 실 항해상황을 간과할 수 있는 문제점이 있다. 본 연구는 실시간 AIS 정보를 활용하여 항로이탈의 변화율에 해당하는 곡률분석, 항로선으로부터 좌우의 변동을 보다 정확하게 모니터링 할 수 있는 이상 거동 선박을 식별하는 방법을 제안한다. 본 연구는 VTS 및 VMS의 응용서비스로서 해양사고의 사전예방을 위한 연안 및 항만수로의 효율적인 관리에 기여할 것이다.

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The Effect of Combustion Promotion in Constant Volume Combustion Chamber with Sub-chamber (부실붙이 정적연소실의 연소촉진 효과)

  • 이상준;김삼석;이종태;이성열
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.3
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    • pp.569-577
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    • 1992
  • The effect of combustion promotion in a constant volume combustion chamber with sub- chamber located in the vicinity of spark plug, was analyzed for variables such as sub- chamber volume and diameter of orifice, and was also compared and evaluated with that of the chamber with sub-chamber which spark plug was located in the sub-chamber. Consequently, it was shown that decrease of duration of combustion in the latter case was larger than in the former case, but comparing by rate of overall combustion promotion that duration of combustion and pressure were both considered, the optimum configuration factor and the effect of combustion promotion were almost same in both cases.

Study on Fatigue Behavior and Rehabilitation of Stringer with Coped Section(I) -Experimental Study on Static and Fatigue Behavior- (절취부를 갖는 세로보의 피로거동과 보수·보강에 관한 연구(I) -정적거동 및 피로거동의 실험적 고찰-)

  • Hwang, Yoon Koog;Chang, Dong Il
    • Journal of Korean Society of Steel Construction
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    • v.9 no.3 s.32
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    • pp.363-375
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    • 1997
  • This study encompasses the performance of static and fatigue test for the 8 large scale test specimens to clarify the fatigue behavior of coped stringer and the effect of the repair and strengthening on the damaged stringer of the floor system in steel railway bridges. For the purpose of the research, the actual stress wave for the existing bridge was measured, the basic stress range frequency histogram was made and the equivalent stress range was calculated. Using the result from the equivalent stress range made by adjusting the stress range, the static and fatigue test was carried out by identifying the previous rehabilitation and after. As the result of the static tests, it was revealed that the level of local stress under the S1 specimen test of the real equivalent stress range was similar to tensile strength of the test material, and it was consistent with the requirement of the initiation condition of the fatigue crack. Through the various rehabilitation methods to the damaged specimens, the effects of the repair and reinforcement were analyzed. According to the results of the repair of effect, bolting the high tension bolt over the stop hole was confirmed to be more adequate method than drilling only stop hole to delay the fatigue crack growth. Futhermore, in case of the stringer subjected by bending moment, the reinforcement over the upper flange side was determined to be a useful strengthening method, and the reinforcement to the web of the stringer was not appropriate to accomodate as a adequate strengthening method. Also it was confirmed that the category of the fatigue design for the coped stringer met with the category E specified on the fatigue design criteria of the Highway Standard Specification in Korea.

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Combustion Characteristics of Volume Variation of Torch in a CVCC (토치 점화 장치의 체적에 따른 연소특성 파악)

  • Kwon, Soon-Tae;Kim, Hyeong-Sig;Choi, Chang-Hyeon;Park, Chan-Jun;Ohm, In-Young
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 2010.04a
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    • pp.166-170
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    • 2010
  • Six different size of torch-ignition device were applied in a constant volume combustion chamber for evaluating the effects of torch-ignition on combustion. The torch-ignition device was designed six different volumes and same orifice size. The combustion pressures were measured to calculate the mass burn fraction and combustion enhancement rate. In addition, the flame propagations were visualized by shadowgraph method for the qualitative comparison. The result showed that the combustion pressure and mass burn fraction were increased when using the torch ignition device. And the combustion duration were decreased. The combustion enhancement rates of torch-ignition cases were improved in comparison with conventional spark ignition. Finally, the visualization results showed that the torch-ignition device the torch-ignition induced faster burn than conventional spark ignition due to the earlier transition to turbulent flame and larger flame surface, during the initial stage. And the initial flame propagation was effected torch-ignition volume.

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An Analysis of Influences of Education Satisfaction of Beauty Salon Franchises on Turnover factors Mediated by Education need (프랜차이즈 직영점 미용실의 교육만족도가 교육요구도를 매개로 이직요인에 미치는 영향)

  • Kim, Min-seok;Ko, Kyoung-sook
    • Journal of Convergence for Information Technology
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    • v.11 no.5
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    • pp.232-241
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    • 2021
  • This study was conducted to prepare a countermeasure for turnover due to the effect of education satisfaction at franchise stores on turnover factors through the medium of education requirements. In the method of collecting data, 237 copies of the questionnaire method were used as the final data. The results are first, the analysis of educational requirements in general characteristics shows that academic background (F=5.655, p<).01), Analysis of the factors for turnover shows that position (t=-2.809, p<).Significant differences were shown in 01. Second, educational satisfaction is the educational requirement (r=-.16, p<).The correlation between 05) and turnover factors (r=-.18) is significant, and the educational requirement is turnover factors (r=.53, p<).It is shown to be a significant static correlation with 01. Third, designers (B=.25), t=2.332, p<.05) and educational requirements (B=.88, t=9.313, p<).001) has been shown to have significant static effects. Fourth, the educational requirements for educational satisfaction and turnover factors are significant (β=.52, p<).We can see that it is fully mediated by 001.Therefore, it is believed that it will be possible to investigate quarterly satisfaction and demand after communication and training with workers at direct stores, and reduce turnover through various curriculum education.

An Evaluation of the Student Performance and Perception of the Food and Nutrition Subject in the Elementary School Curriculum in Incheon, Korea (실과의 식품영양 단원에 관한 교사 학생의 인지 및 학생의 지식, 태도, 기능간의 상관 연구 -인천직할시 공립국민학교를 중심으로-)

  • 김수자
    • Journal of Korean Home Economics Education Association
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    • v.5 no.1
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    • pp.97-111
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    • 1993
  • 본 연구는 국민학교 실과 과목의 식품 영양 단원에 관한 교사, 학생의 인지 및 학생의 지식, 태도, 기능 평가를 위하여 71개 인천시내 공립 국민학교 4,5,6학년 교사 510명과 12개교학생 1,754명을 대상으로 설문조사를 통한 내용을 분석한 것으로 연구의 목적은 1)실과의 정해진 교육목표에 관한 교사의 인지정도 규명 2)식품, 영양 단원에서 교사가 중요하다고 인지하는 내용과 가르치기에 어려움을 느끼는 내용 규명 3)교사가 인지하는 식품영양 단원학습을 증진하기 위한 요소 4) 학생들이 흥미를 느끼는 내용 5)본 단원 학습 후 학생의 지식, 태도, 기능 정도 6)지식, 태도 기능간의 상호 상관관계 규명 등이며 그 연구결과는 다음과 같다. 1. 교사들이 인지하는 실과의 정해진 교육목표는 거의 모두가 중요한 것으로 나타났다. 2. 교사들이 인지하는 식품 영양 단원의 중요한 내용은 영양과 질병과의 관계, 식품위생, 식품저장 등이며, 가장 중요하지 않은 내용으로는 영양 필요량이었다. 또한, 지도에 어려움을 느끼는 내용은 영양 필요량, 조리준비, 식품구성/함유량 등이며 어려움을 느끼지 않는 내용은 영양과 질병과의 관계, 식품위생, 식품저장 등이었다. 3. 교사가 인지하는 단원 학습 증진을 위한 긍정적 요소는 적합한 실습설비와 자료, 시청가자료등이었고 부정적 요소는 남교사, 실험 실습이 필요한 부분은 숙제로 미루는 것 등이었다. 4. 학생들이 흥미를 느끼는 내용으로는 간단한 음식 만들기, 영양소의 기능, 영양문제 등이었고, 쥬스나 차 준비, 조리연료, 부엌용구 사용법 등은 흥미를 느끼지 못하는 내용이었다. 5. 학생의 학업성취 중 지식은 4학년이 식품위생, 기초식품군이, 5학년은 알맞은 조리용구, 조리원리, 6학년은 여가활용의 뜻, 올바른 예절 등이 90% 이상 바르게 답하였고 5학년의 삶은 달걀의 화학적 변화, 감자의 주된 영양 등은 60%이하였다. 6 태도 테스트 결과는 5학년이 4,6학년보다 약간 높은정도(Mn=3.653) 였으나 기능테스트에서는 4학년이 5,6학년보다 약간 낮게 (Mn=3.0) 나타났다(구체적인 것은 본문 참조). 7, 4, 5, 6학년 모두 지식, 태도 기능 간에 정적 상관을 나타내었는데 특히 태도와 기능 사이에는 4학년 r=.7166, 5학년 r=.5175, 6학년 r=.6796을 나타내었고 지시과 태도(4학년 r=.1546, 5학년 r=.0872, 6학년 r=.2192)와 지식과 기능사이에서는 (4학년 r=.1631, 5학년 r=.0585, 6학년 r=.2521)태도와 기능간보다 약한 상관관계를 보였다.

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Applicability Evaluation of Precast Deck to the Maglev Guideway System : Static Performance Test (프리캐스트 바닥판의 자기부상열차 가이드웨이 시스템 적용성 평가 : 정적 성능 실험)

  • Jin, Byeong-Moo;Kim, In-Gyu;Kim, Young-Jin;Lee, Yun-Seok;Ma, Hyang-Wook;Oh, Hyun-Chul
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.985-988
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    • 2008
  • Maglev is a system that a train runs levitated above a rail. Therefore it is very important to maintain a constant levitation gap for achieving serviceability and ride comfort. This study is a cooperation research subject of the 3-1 subject, performance improvement of maglev track structures, of the Center for Urban Maglev Program in Korea, started in 2006. The aim of this study is development of rapid constructions of bridge superstructure for maglev. At present, precast deck is widely used because of its superiority to cast-in-place concrete on quality and the term of works. The research group suggested basic systems of maglev guideway with PSC-U type and trapezoidal open steel box type girder, and precast deck, cooperating with Korea Railroad Research Institute, the managing institute of the 3-1 subject. In this study, full-scale structure was fabricated for structural safety evaluation of precast decks and rail, and a static performance test of those structures was performed.

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A Study on the Steady-State Characteristics of Symmetric Pintle Nozzle with Varying Position of Pintle and Change in Altitude (대칭형 핀틀 노즐의 핀틀 위치와 고도 변화에 대한 정상상태 특성 연구)

  • Jeong, Kiyeon;Kang, Dong-Gi;Jung, Eunhee;Lee, Daeyeon;Choi, JaeSung
    • Journal of the Korean Society of Propulsion Engineers
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    • v.23 no.1
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    • pp.33-45
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    • 2019
  • In this study, numerical simulations were performed to investigate the steady-state characteristics of a symmetric pintle nozzle by varying the position of the pintle and the altitude. The pintle nozzle shape was used in a linear pintle nozzle that had been analyzed prior to the study, and the boundary conditions of the chamber were considered to be according to the propellant burn-back characteristics. A software was used to perform a verification analysis of the square nozzle, pintle nozzle, and high-altitude conditions with an appropriate analytical technique. The pintle position had three different nozzle throat area conditions-: fully closed, half open, and fully open, and the altitude was set at 0, 5, and 20 km. The study compared the thrust, pintle drive load, and static stability at each condition.

Verification of VIIRS Data using AIS data and automatic extraction of nigth lights (AIS 자료를 이용한 VIIRS 데이터의 야간 불빛 자동 추출 및 검증)

  • Suk Yoon;Hyeong-Tak Lee;Hey-Min Choi;;Jeong-Seok Lee;Hee-Jeong Han;Hyun Yang
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2023.05a
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    • pp.104-105
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    • 2023
  • 해양 관측과 위성 원격탐사를 이용하여 시공간적으로 다양하게 변하는 생태 어장 환경 및 선박 관련 자료를 획득할 수 있다. 이번 연구의 주요 목적은 야간 불빛 위성 자료를 이용하여 광범위한 해역에 대한 어선의 위치 분포를 파악하는 딥러닝 기반 모델을 제안하는 것이다. 제안한 모델의 정확성을 평가하기 위해 야간 조업 어선의 위치를 포함하고 있는 AIS(Automatic Identification System) 정보와 상호 비교 평가 하였다. 이를 위해, 먼저 AIS 자료를 획득 및 분석하는 방법을 소개한다. 해양안전종합시스템(General Information Center on Maritime Safety & Security, GICOMS)으로부터 제공받은 AIS 자료는 동적정보와 정적정보로 나뉜다. 동적 정보는 일별 자료로 구분되어있으며, 이 정보에는 해상이동업무식별번호(Maritime Mobile Service Identity, MMSI), 선박의 시간, 위도, 경도, 속력(Speed over Ground, SOG), 실침로(Course over Ground, COG), 선수방향(Heading) 등이 포함되어 있다. 정적정보는 1개의 파일로 구성되어 있으며, 선박명, 선종 코드, IMO Number, 호출부호, 제원(DimA, DimB, DimC, Dim D), 홀수, 추정 톤수 등이 포함되어 있다. 이번 연구에서는 선박의 정보에서 어선의 정보를 추출하여 비교 자료로 사용하였으며, 위성 자료는 구름의 영향이 없는 깨끗한 날짜의 영상 자료를 선별하여 사용하였다. 야간 불빛 위성 자료, 구름 정보 등을 이용하여 야간 조업 어선의 불빛을 감지하는 심층신경망(Deep Neural Network; DNN) 기반 모델을 제안하였다. 본 연구의결과는 야간 어선의 분포를 감시하고 한반도 인근 어장을 보호하는데 기여할 것으로 기대된다.

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