• Explosives and Blasting
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• v.38 no.2
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• pp.22-35
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• 2020

Recently, electronic detonators have been widely used in various sites. Electronic detonators are often used for the purpose of reducing the noise and vibration produced by blasting. In addition, electronic detonators are used for precision blasting at sites where mechanical excavation techniques are applied due to proximity of safety things or where blasting by conventional detonators are not possible. Various technologies are being attempted at the blasting site to increase constructivity and lower production costs by using electronic detonators. In this paper, we would like to introduce a construction case that use of electronic detonators in the situation of safety things being adjacent increases the efficiency of construction while meeting the ground vibration criteria of Ministry of Land, Infrastructure, and Transport. The blasting was carried out at domestic and overseas shaft using HiTRONIC II™, produced by Hanwha. Generally the shaft blasting is performed by dividing the blasting surface because of the noise and vibration caused by the blasting. but, in the case introduced in this paper, the blasting was carried out once without dividing the blasting surface, thus the construction period could be shortened.

• Explosives and Blasting
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• v.40 no.2
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• pp.25-34
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• 2022

Recently, there has been an increasing number of cases of improving constructability by using electronic detonators with precise delay time in tunnel blasting sites. This case is a case of conducting test blasting using with non-electric detonator and electronic detonator at the site of 『Seoul Metropolitan Area Express Railroad Route A Private Investment Project Section 00』 that requires careful management of vibration and noise. Although this site was designed with a non-electric detonator, it was attempted to improve the advance rate and control vibration and noise by mixing the non-electric detonator and the electronic detonator due to the decrease in the advance rate. As a result of the blasting, the target value was achieved with an advance rate of about 85% and a maximum measured value of vibration and noise is 0.215cm/sec and 73.22dB(A) which were measured below regulatory standards. As blasting works in downtown areas, it is necessary to designate measurement and management objects to continuously manage vibration and noise.

• Cement
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• s.152
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• pp.41-45
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• 2000

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.97-108
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• 2010

발포우레탄 패커를 이용한 압력식 쏘일네일링 공법은 기존 쏘일네일링 공법의 단점을 보완하기 위하여 개발되었으며, 그라우팅 두부에 패커를 설치하여 네일 정착부를 완전히 밀폐하고 압력 그라우팅을 실시하여 정착부의 유효직경 및 인발저항력을 증가시켜 안전율을 향상시키는 공법이다. 압력식 쏘일네일링 공법에 대한 효용성을 검증하기 위하여 발포우레탄 패커 특성시험 및 현장조건을 묘사한 실내 그라우팅 주입실험, 현장시험 및 FEM해석을 수행하였다. 본 공법의 필수요소인 발포우레탄 패커의 정착력 확인을 위한 패커 특성시험 결과, 공내에 작용하는 압력에 대하여 패커가 충분히 저항함을 알 수 있었으며, 인발저항력 증가 원인 분석을 위한 실내 및 현장 시험결과, 압력 그라우트에 의하여 그라우트의 품질확보, 보강력증가 및 주변지반의 압밀효과를 확인 하였다. 끝으로 압력식 쏘일네일링 공법을 적용한 사면 및 흙막이 벽체 설계/시공 사례를 분석하여 현장 적용시 본 공법의 효용성 및 대처능력의 우수함을 입증하였다.

• IE interfaces
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• v.10 no.1
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• pp.95-107
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• 1997

본 논문은 실험계획법을 반도체 공정 및 소자 시뮬레이터에 적용하여, 시뮬레이션 회수를 최소화하고, 동시에 현장과 유사하게 시뮬레이터 내부 파라미터가 튜닝 될 수 있도록 하는 교정 문제에도 활용된 반도체 공정 최적화 사례를 소개한다. 또한, 일반적 시뮬레이터가 실제 현장과의 차이점으로 갖는 문제인 동일한 입력 값에 대해 항상 같은 출력 값이 산출되는 점을 공정의 규격을 고려해 시뮬레이션 함으로써 현장에서의 재현성을 높이고자 하였다. 이는 $0.8{\mu}m$급 BIMOS 공정의 기본 소자 중 하나의 NPN 트랜지스터의 전류이득(Current Gain : hFE) 특성을 최적화하기 위한 주요 공정조건 결정과 연관된 것이며, 기존 방법에 비해 시뮬레이션 횟수를 줄이는 동시에 현장에 직접 투입되는 검증 로트를 최소화시켜 비용과 시간을 절감할 수 있었다. 또한, 얻어진 추전 조건에서 실제 생산된 검증 로트를 통해 시뮬레이션으로부터 얻어진 결과들이 재현됨으로써 제시된 방법의 유용성을 확인하였다.

• Journal of Korean Institute of Fire Investigation
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• v.9 no.1
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• pp.47-53
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• 2006

본 논문은 화재발생 이후에 화재현장의 조건에 따라 분전반의 주차단기 전원측 단자에서의 트래킹 현상 진행 가능성에 대하여, 화재현장 조사사례를 들어 고찰하였다. 화재현장 조사과정에서 분전반의 주차단기 전원측 단자에서 트래킹 형태가 식별됨에도 불구하고 그 부하측에서 전기적인 특이점이 식별되는 경우에는, 단순히 트래킹 형태가 식별되는 점만으로 발화원인을 판정하는 자세를 지양하고, 구체적인 연소형태를 검토하여 발화개소, 연소확대 경로 등의 해석 및 전체적인 전기계통의 고찰을 통하여, 분전반 주차단기에서의 발화원인 등을 판정해야되며, 또한, 화재현장의 정밀조사 없이 분전반 및 차단기의 조사와 해석만으로는 발화여부 또는 발화원인에 대하여 논단하는 것이 어렵다는 결론을 도출하였다.

• Magazine of the Korea Concrete Institute
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• v.8 no.4
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• pp.39-45
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• 1996

• Journal of the Korea Institute of Building Construction
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• v.4 no.2
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• pp.54-57
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• 2004

• Journal of the Korean earth science society
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• v.23 no.4
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• pp.309-323
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• 2002

This qualitative study investigated preservice teachers' understandings of the ontology and epistemology underlying constructivist notions of learning through four in-depth interviews. Of the sixteen participants in a larger study, five significantly changed ontological and epistemological beliefs and eleven did not. This study focused on these eleven teachers who have hardly changed their philosophical beliefs throughout the teacher education program. Ten teachers who consistently maintained the scientific realist beliefs were presented as a composite case (Young's case). Among the eleven teachers, there was one outlier who had consistently maintained an idealist and relativist epistemological position from the beginning of the study and was subjected to another case analysis (Ben's case). These cases corroborated the assertion that each individual's deeply entrenched ontological and epistemological beliefs are very hard to change. For researchers, this study offers insights into the reasons that preservice teachers give for non-changes in their thinking about learning to teach. The study also examines preservice teachers' perceived constraints in implementing their ideal pedagogies and the influence of the teacher education program on their pedagogical beliefs changes. The benefits and influences of the M.Ed. program's theoretical coursework and the field experiences on these teachers' learning-to-teach experiences are addressed with rich data. The implications for teacher educators as well as for the instructional practices of preservice teacher education programs are discussed. This research emphasize necessity of the field-based teacher education program and the need of empowering experienced school teachers as teacher educators in teacher preparation and professional development.

• Korean Journal of Social Welfare
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• v.64 no.3
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• pp.127-153
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• 2012

This study aims to develop the case management activities inventory relevant to community-based mental health settings. The comprehensive literature review was conducted to define the concepts and activities for the case management process. After the content analysis from the professional scholar and the mental health-related worker, 83 items were constructed. A survey was conducted to 265 case managers in community mental health centers. Through exploratory factor analysis, reliability and validity analysis, finally 8 factors and 43 items were identified.