• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.2
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• pp.89-97
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• 2003

Experimental model studies were carried out to evaluate the end condition for drilled shafts by applying elastic impact on the top of the shaft, which is one of the various methods using stress waves. Typical impact responses corresponding to the various end conditions including free, fixed, rock-socketed, and soft-bottom with good and poor side contact conditions, were investigated. In order to simulate these renditions, mock-up shaft models made of cement mortar were used. Small-scale laboratory experiments were also performed, and field tests were carried out for the shafts that were socketed into weathered rock. It is found that the rock-socketed condition and depth of penetration into rock ran be identified from the reflection at the interface between the soil and rock in the waveform. The soft bottom rendition can be identified, only when the side contact between shaft and surrounding rock is poor, whereas it cannot be identified when the side contact is good because the waveform is similar to that of fixed end rendition.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2004.05a
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• pp.185-190
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• 2004

현장 용접 실무자의 경우 익숙한 업무라 하더라도 때로는 시행착오를 겪을 수 있고, 또는 익숙한 용접 작업을 벗어나 새로운 조건으로 용접을 수행해야 하는 경우도 있다. 이 경우 복잡한 용접 기준과 방법을 전산 정보화 하여 마른 시간에 가장 적합한 용접 방법과 용접 조건을 제공해 줄 수 있다면 현장작업의 합리화에 기여 할 수 있을 것이다. 본 연구에서는 이러한 시도로서 연강용접에 국한하여 용접 조건 설정에 관한 전문가의 지식을 전산 정보화 하여 현장 용접 실무자가 쉽게 새로운 용접 조건을 찾는데 도움을 주는 지적 결정 시스템을 구축하고자 하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.239-243
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• 2011

우리나라 주요 수자원인 댐 저수지는 여름철 성층현상으로 인해 많은 수질문제가 발생하여 산기식 수중폭기장치를 설치하고 있다. 그러나 산기식 수중폭기장치의 설계인자들은 대부분 lab-scale의 실험연구를 통해 검토되고 설계에 반영되고 있어 실제 댐 저수지에 적용하기 위해서는 현장적용성을 고려하여 개선될 필요가 있다. 따라서 본 연구는 실제 댐 저수지의 현장조건을 고려하여 CFD 모의실험을 통해 산기식 수중폭기장치의 설계인자인 무차원변수 DN (Destratification Number)과 탈성층 영향반경 및 효율을 검토하였다. 그 결과 현장조건에서의 DN값은 lab-scale 실험조건보다 더 넓은 범위를 가지며, 단위수심당 탈성층 영향반경은 DN값이 증가할수록 감소하는 것으로 분석되었다. 또한 탈성층 효율은 DN값이 증가할수록 선형적으로 증가하다가 증가율이 감소하면서 일정해지는 것으로 분석되었다.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.366-367
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• 2003

토목합성재료의 내후성은 사용되는 원료 물질, 기후조건, 하중조건, 노출 기간 등에 따라 상이한 결과를 나타내며, 이러한 영향인자에 대한 많은 연구가 국내외적으로 이루어졌으나 이는 각 적용지역의 환경조건을 고려하여 실시된 경우로 지역적인 조건과 기후 차이로 국내 여건에 적합한 데이터라 할 수 없다. 본 연구에서는 임시구조물로 적용된 분리형 보강토 옹벽의 전면체를 형성하는 부직포 지오텍 스타일에 대해 현장 적용 노출시험을 실시하였으며 약 1년 간의 지속적인 계측을 통해 실제 국내 현장에서 나타나는 부직포 지오텍스타일의 내후성 거동에 대해서 평가하였다. (중략)

• Journal of the Korea Institute of Building Construction
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• v.17 no.1
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• pp.91-100
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• 2017

The safety management is one of important factors. However, the satisfaction of safety manager is lowering. Therefore, this study focuses on comparing the impact that working conditions have on the job satisfaction of field and safety manager in construction field. The results of in this study, the basic wage, medical care, and leisure activity were analyzed as a positive impact on job satisfaction. In addition, the comparison result of the field manager and safety manager showed that safety manager appeared to be a greater impact on the basic wage than the field manager. Also, this study showed that the medical care and leisure activity have a positive impact on the job satisfaction of field manager, but the industrial accident and accommodation facility have a positive impact on the job satisfaction of safety manager.

• Journal of Korean Tunnelling and Underground Space Association
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• v.3 no.2
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• pp.13-22
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• 2001

In this study, numerical analyses on cut-and-cover tunnel linings were performed using different modeling methods based on both structural and geotechnical engineering. The purpose was to find a relatively more reasonable modeling method and boundary conditions. The results of the study revealed problems associated with each modeling method and factors influencing the behavior of cut-and-cover tunnel lining. A method was proposed allowing the simulation of field condition in a more rational way. It was indicated that, under the given conditions, displacements and member forces occurring on concrete lining could be different as much as 53% depending on the type of modeling method applied; and 32% depending on the boundary conditions employed. Determination of boundary conditions properly simulating actual field conditions and verification of prediction based on instrumentation are essential for rational design and analysis.

• Electric Engineers Magazine
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• s.334
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• pp.30-35
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• 2010

본 고에서는 현장에 설치된 태양광발전시스템의 출력 측정 방법을 제시 하였다. 태양광발전시스템은 햇빛이라는 자연조건에 따라서 출력이 수시로 변동하기 때문에 태양전지 제조자가 제시하는 규격은 제작시에 태양전지를 표준 시험조건(즉, STC, Air Mass 1.5, 일사량 1000[$W/m^2$], 온도 $25^{\circ}C$기준)에서 시험한 성능 규격을 제시하고 있다. 그러나 적용현장에 설치된 태양전지는 인위적으로 표준 시험조건을 만들어 줄 수 없기 때문에 출력을 측정하면 제조자가 제시한 성능 규격이 제대로 나오는지 여부가 관심사다. 그렇기 때문에 설치현장에서 자연 조건에서 측정된 출력에다 태양전지 제작사에서 제시한 온도 및 일사량 특성곡선에서 추출된 보정계수를 적용하여 보정 출력을 산정해서 보정 출력을 토대로 제조사에서 제시한 규격에 부합하는 지 여부를 판단할 수 있는 방법을 제안하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.2
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• pp.125-133
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• 2014

In this study, TBM selection methods to meet soil and site conditions were presented. Factors and excavation equipment affecting TBM selection by soil and environmental condition were selected and classified. Weights between equipment and influencing factors selected were calculated by applying the AHP (Analytic Hierarchy Process) method. The results of the analysis influence factors, Ground condition was a major factor in objective factors and strength was a major factor in the hard condition of criteria factors and water pressure was a major factor in the soft ground condition of criteria factors. In Environment condition, existence of adjacent structures was evaluated more important than existence of feasible site. Lastly, Adequacy was verified through the deduction of results that coincide with input equipment by applying derived weights to actual site conditions.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.589-592
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• 2008

Recently, as importance of quality control of the structure has been recognized, non-destructive testing, determining quality of the structure without damage, has been widely applied. However, its application has been primarily focused on laboratory development because variety of parameters in field has been not fully experienced and understood. This study aims to evaluate the field applicability of the ultrasonic testing method for PC beams. Material properties of 18 cylinders, cured in the same field condition, were measured up to 60 days and compared to those of the ultrasonic measurements from 34 PC beams in field before tensioning. Test results indicate that uni-axial strength and elastic modulus of PC beams can be predicted within reasonable range using the ultrasonic technique. However, it is also noted that considerations on field condition is required to increase the reliability of estimation.

• Journal of the Korean GEO-environmental Society
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• v.15 no.3
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• pp.49-55
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• 2014

Characteristics of sedimentation of dredged soil is depended on the field condition and characteristics of dredged soil because dredged fill ground was formed by various field condition, sedimentation and self-weight consolidation process of dredged soil. Dredged fill ground is formed as separated sedimentary layer by characteristics of dredged soil. Therefore, it requires some special test method to consider a various field condition, characteristics of sedimentation and self-weight consolidation of dredged soil. In this study, in order to identify the characteristics of sedimentation of dredged soil with disposing velocity geo-centrifuge test and laser particle size analyzer were performed. As a results, river and mixed dredged soil show the separation sedimentation by soil particle size. And sedimentation of clayey dredged soil is parallel to the bottom surface of dredged fill space.