• 한국강구조학회 논문집
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• 제25권6호
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• pp.635-647
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• 2013

PSRC 기둥은 앵글을 콘크리트에 매입시킨 기둥으로, 단면의 외곽 코너에 배치되는 앵글이 기둥의 휨-압축에 저항한다. 본 연구에서는 KBC 2009에 따라 압축력을 가한 기둥에 대하여 횡방향 반복가력 실험을 통하여 내진성능을 검증하였다. 기둥 종류, 연속후프근 적용, 앵글에 스터드 적용을 실험 변수로 고려하였으며, 2/3 스케일을 갖는 한 개의 SRC 합성기둥과 세 개의 PSRC 합성기둥을 실험하였다. 실험결과, KBC 2009로 예측한 PSRC 합성기둥의 하중재하능력은 실험결과와 잘 일치하였으며, 변형능력과 에너지 소산에 있어서 우수한 성능을 보여주었다. PSRC 합성기둥은 반복하중으로 인한 콘크리트 피복 탈락 이후, 앵글 및 주철근의 좌굴에 의해 실험체의 하중재하능력이 감소하였다. 특히, 연속후프근을 적용한 PSRC 합성기둥은 앵글의 조기 국부좌굴이 억제되어 기존 PSRC 합성기둥에 비해 연성능력이 향상되었다.

• 지질공학
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• 제17권1호
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• pp.65-73
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• 2007

지하발전소 시공을 위한 지하대규모 공동 굴착시 소성영역이 크게 발생되므로 일반적으로 장대록볼트를 이용한다. 그러나 장대록볼트 설치시 록볼트 길이에 따른 휨발생과 정착효과에 대한 문제가 야기되고 있다. 따라서 본 연구는 지하대규모 공동 굴착시 가장 효율적인 정착방식을 결정하기 위하여 천단부와 측벽부에서 장대록볼트의 길이를 5.0m, 7.5m, 10.0m, 15.0m와 정착방식을 톱니 모양, 홈 모양 및 매끈한 모양으로 변경시키면서 현장인발시험을 실시하였다. 현장인발시험에 의하여 하중과 변위를 단계별로 측정하고 거동특성을 평가하여 개선된 정착방식을 제시하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제25회 추계학술대회논문집
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• pp.346-350
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• 2005

연소압 50bar 이상의 연소조건에서 반복 사용이 가능하도록 제작된 물냉각형 칼로리미터에서 막냉각량 및 작동점의 변화 시 열유속의 특성을 알아보았다. 분사기 헤드와 칼로리미터 사이에 12개의 오리피스를 갖는 막냉각 링이 삽입된다. 칼로리미터는 연소실부와 노즐부로 구성되어 있으며, 총 19개의 냉각 채널로 구성되어 있다. 설계점 연소시험 시 막냉각량이 주 연료의 10.5% 유량일 때, 막냉각량이 없는 경우보다 노즐목에서의 최대 열유속은 약 30% 감소되었고, 막냉각량이 없는 경우, 탈설계점(OD3)이 설계점에 비해 노즐목에서의 최대 열유속이 약 31% 증가 하였다.

• Earthquakes and Structures
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• 제8권5호
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• pp.1039-1054
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• 2015

The purpose of this study was to evaluate the seismic performance of weak-axis column-tree type connections used in steel moment frames. These connections are composed of a shop-welded and fieldbolted steel structure and can improve welding quality. On this basis, column-tree type connections are widely used in steel moment resisting frames in Korea and Japan. In this study, splices designed with a semirigid concept regarding the seismic performance of column-tree connections were experimentally evaluated. The structures can absorb energy in an inelastic state rather than the elastic state of the structures by the capacity design method. For this reason, the plastic hinge might be located at the splice connection at the weak-axis column-tree connection by reducing the splice plate thickness. The main variable was the distance from the edge of the column flange to the beam splice. CTY series specimens having column-tree connections with splice length of 600 mm and 900 mm were designed, respectively. For comparison with two specimens with the main variable, a base specimen with a weak-axis column-tree connection was fabricated and tested. The test results of three full-scale test specimens showed that the CTY series specimens successfully developed ductile behavior without brittle fracture until 5% story drift ratio. Although the base specimen reached a 5% story drift ratio, brittle fracture was detected at the backing bar near the beam-to-column connection. Comparing the energy dissipation capacity for each specimen, the CTY series specimens dissipated more energy than the base specimen.

• 약학회지
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• 제59권1호
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• pp.23-28
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• 2015

Everyone has own color preference and the color preference can affect human psychology in various good or bad ways. Especially patients with chronic diseases often have depressed mood to take pills for their disease treatment. Therefore we evaluate the possibility of their color preference to pharmacotherapy in good way which increases the compliance of pharmacotherapy. We performed this study by a Questionnaire survey for total 150 agreed patients at K University hospital from Aug 7 to Sep 30, 2014. Questionnaire survey was performed to choose color of providing color kit (11 different color range kit) depend on each 16 questions which asked the patient characteristics, health condition, general color preference, color preference for medicine and expectation for drug compliance. In results, most preferred color was blue (20%), whereas disliked color was black (30%) in general life. However, most preferred color for pill was white (32%), for syrup was also white (31%) or orange (28%), and for vitamin was yellow (47%). When we asked the possibility of increasing compliance, if the current taking pill color will be changed for your preference color like a candy bar, 50.4% of respondents marked 4 or 5 of like-scale expressing positive opinion on it. In conclusion, compliance is very important to succeed the treating disease and may apply the psychologic application such as each patient color preference for drug compliance in the future.

• 콘크리트학회논문집
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• 제15권6호
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• pp.894-901
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• 2003

본 연구의 목적은 비내진 상세를 가진 RC 구조물의 이력거동 특성과 내진성능 및 특성을 알아보기 위한 것이다. 이를 위해 10층 RC구조물의 내 외부 접합부를 선정하여 슬래브의 유무, 접합부내에서의 전단철근 유무, 외부 접합부의 보 하부 주근의 정착방향에 따라 6개의 1/3 축소 실험체를 만들어 반복횡하중 실험을 수행하였다. 실험결과 내부 접합부의 경우 슬래브의 유무에 관계없이 내진 비내진 상세의 상이에 따른 강도나 연성 능력의 변화는 크지 않는 것으로 나타났고, 외부 접합부의 경우 내부 접합부와는 달리 접합부 전단 보강근의 유무뿐만 아니라 하단 주철근 정착방향에서도 차이가 나기 때문에 비내진 상세의 강도나 연성 능력이 각각 10∼20%와 27% 정도 작은 것으로 나타났다. 또, 비내진 상세를 가지는 경우 국부 변형이 한 곳에서 집중되어 크게 나타남을 알 수 있으며, 슬래브가 있음으로 인해 휨에 의한 회전각을 억제하고 상향 전단변형을 억제하는 것으로 나타났다. 한편 보-기둥 접합부에서의 전단 보강근은 전단변형률에 거의 영향을 끼치지 않는 것으로 나타났다.

• 생물환경조절학회지
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• 제23권4호
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• pp.269-280
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• 2014

To cope with increasing of vegetables and flowers consumptions, horticulture facilities have been modernized. Korea government recently announced construction plan of new greenhouse complex at reclaimed land. However wind characteristics of reclaimed land is totally different from those of inland, wind pressure on greenhouse built in reclaimed land should be carefully evaluated to secure structural safety on the greenhouse. In this study, as a first step, wind pressure coefficient and local wind pressure coefficient on even-span greenhouse were measured using wind tunnel test. ESDU was adopted to realize wind characteristics of reclaimed land such as wind and turbulence profiles. From the wind tunnel test, when wind direction was 0 degree, it was concluded that KBC2009 standard underestimated scale of wind pressure coefficients at roof area of greenhouse whereas NEN-EN2002 standard underestimated those at every surface of greenhouse. When wind direction was 90 degree, both standards did not well reflect the characteristics of wind pressure distribution. From the analysis of local wind pressure coefficients according to wind direction conditions, design of covering, glazing bar of greenhouse where large effects of the local wind pressure were estimated should be well established. Wind pressure coefficients and local wind pressure coefficients according to parts of the greenhouse were finally suggested and these results could be practically used for suggesting new design standards of greenhouse.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권3호
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• pp.1086-1103
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• 2020

The automatic identification and classification of image-based weld defects is a difficult task due to the complex texture of the X-ray images of the weld defect. Several depth learning methods for automatically identifying welds were proposed and tested. In this work, four different depth convolutional neural networks were evaluated and compared on the 1631 image set. The concavity, undercut, bar defects, circular defects, unfused defects and incomplete penetration in the weld image 6 different types of defects are classified. Another contribution of this paper is to train a CNN model "RayNet" for the dataset from scratch. In the experiment part, the parameters of convolution operation are compared and analyzed, in which the experimental part performs a comparative analysis of various parameters in the convolution operation, compares the size of the input image, gives the classification results for each defect, and finally shows the partial feature map during feature extraction with the classification accuracy reaching 96.5%, which is 6.6% higher than the classification accuracy of other existing fine-tuned models, and even improves the classification accuracy compared with the traditional image processing methods, and also proves that the model trained from scratch also has a good performance on small-scale data sets. Our proposed method can assist the evaluators in classifying pipeline welding defects.

• KCI Concrete Journal
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• 제12권2호
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• pp.23-30
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• 2000

This paper presents behavior of concrete pavement at transverse joint subject to static test load. The test was conducted on 1/10 scale model in the laboratory. Load transfer across the crack is developed either by the interlocking action of the aggregate particles at the faces of the joint or by a combination of aggregate interlock and mechanical devices such as dowel bars. In this study, significant three variables considered to the performance of joints were selected. : (a)diameter of dowel bars(2.5mm, 3.0mm, 4.0mm), (b)presence or absence of dowel bars, (c)aggregate types(crushed stone, round stone). Experimental results were analyzed to find relationships among displacement of discontinuous plane at jointed slab, load transfer efficiency and joint opening, etc. Displacement of discontinuous plane at joint was decreased according to the increase of dowel bar diameter. In addition, it is found that model slabs made using crushed stone had better load transfer characteristics by aggregate interlock than model slabs made using similarly graded round stone. Displacement of discontinuous plane was increased according to the increase of loading. In addition, it was decreased as dowel diameter(2.5mm, 3.0mm, 4.0mm) was increased. In the case of slab without dowel bars, displacement of discontinuous plane was greatly increased and load transfer effciency of slab applied crushed stone was shown 30 percent greater than round stone. In addition, load transfer efficiency of slabs, which were made using crushed and round stone without dowel bars, was decreased to 20 percent and 30 percent, respectively as it was compared with slabs made us-ing dowel bars.

• Structural Engineering and Mechanics
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• 제64권5호
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• pp.671-681
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• 2017

This study investigates the structural performance of 3D steel pipe rack suspended scaffolding systems. For the purpose, a standard full scale 3D steel pipe rack suspended scaffolding system considering two frames, two plane trusses, purlins and wooden floor is constructed in the laboratory. A developed load transmission system was placed in these experimental systems to distribute single loads to the center of a specific area in a step-by-step manner using a load jack. After each load increment, the displacements are measured by means of linear variable differential transducers placed in several critical points of the system. The tests are repeated for five different system conditions to determine the structural performance. The means of system conditions is the numbers of the tie bars which are used to connect plane trusses under level. Finite elements models of the 3D steel pipe rack suspended scaffolding systems considering different systems conditions are constituted using SAP2000 software to support the experimental tests and to use the models in future studies. Each of models including load transmission platform is analyzed under a single loading and the displacements are obtained. In addition, to calibrate the numerical models some uncertain parameters such as elasticity modulus of wooden floor and connection rigidity of purlins to plane trusses are assessed experimentally. The results of this work demonstrate that when increasing numbers of tie bars the displacement values are decreased. Also the results obtained from developed numerical models have harmony with those of experimental. In addition, the scaffolding system with two tie bars at the beginning and at the end of the plane truss has the optimum structural performance compared the results obtained for other scaffolding system conditions.