• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.203-210
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• 2006

A procedure for determining the lateral load pattern for pushover analysis which includes higher mode effects is presented in this study. It is well-known that the details of future earthquakes at particular site is almost impossible to predict accurately and that the code-design spectra try to represent at least the average nature of probable future earthquakes. Thus the code-design spectrum is directly used as the input earthquakes in this paper when incorporating higher mode effects in the pushover analysis so that the efforts for selecting input motions and constructing response spectrum needed in some existing method could be avoided. A case study based on the time history analysis of a irregular steel moment frame showed that the procedure proposed in this study generally outperforms various pushover analysis procedures of ATC-40 and FEMA 273. However, the proposed procedure tended to be conservative as compared with the time history analysis method.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.372-372
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• 2019

본 논문에서는 격자 기반의 2차원 침수해석 모형인 G2D(Grid based 2-Dimensional land surface flood model)의 GUI 개발에 대해서 기술하였다. G2D 모형은 ASCII 래스터 포맷의 DEM을 이용하여 정형 사각격자로 구성되는 침수모의 도메인을 설정하고, 수위, 수심, 유량 등의 경계조건과 강우와 유량을 연속방정식의 생성항으로 사용하여 2차원 침수모의를 한다. 주요한 침수모의 결과는 ASCII 래스터 포맷을 가지는 수심과 수위 등이다. 이와 같이 G2D 모형은 ASCII 래스터 파일을 주로 이용하고 있다. 본 연구에서는 우선 래스터 파일의 전후처리와 침수모의 결과의 가시화에 대한 편의성을 높이기 위해서 GIS 소프트웨어를 이용하여 GUI를 개발하고자 하였다. 이와 더불어 사용자들이 소프트웨어 구매 비용에 대한 부담을 없애고, 편리하게 사용할 수 있는 오픈소스 소프트웨어를 이용하고자 하였으며, 이 두 가지 조건을 만족할 수 있는 QGIS를 이용해서 G2D 모형의 GUI인 QGIS-G2D를 개발하였다. QGIS-G2D는 QGIS의 plug-in으로 실행된다. QGIS-G2D는 G2D 모형의 실행에 필요한 프로젝트 파일(.g2p)을 GUI를 이용해서 만들 수 있으며, 모의결과를 애니매이션 등으로 가시화 할 수 있는 후처리 기능을 포함하고 있다. 또한 QGIS-G2D는 DEM 수정 기능과 같이 G2D 모형의 입력자료 전처리를 위해서 QGIS plug-in으로 제공되는 여러 가지 기능을 함께 이용할 수 있다. 또한 물리적 분포형 강우-유출 모형인 GRM(Grid based Rainfall-runoff Model)의 QGIS plug-in인 QGIS-GRM과 연계하여, 유역 유출모의와 침수모의를 QGIS 환경에서 함께 수행할 수도 있다. 개발된 소프트웨어는 오픈소스 플랫폼인 GitHub(https://github.com/floodmodel/)를 통해서 제공된다. 본 연구를 통해서 홍수해석에 필요한 강우-유출 모의와 침수모의를 위한 모형을 제공하고, 이를 편리하게 활용할 수 있는 오픈소스 소프트웨어를 제공할 수 있었다. 이러한 연구들은 홍수 분야의 전문가들에 의해서 다양한 분야의 홍수해석에 사용될 수 있을 것으로 기대한다.

• Journal of The Korean Association For Science Education
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• v.38 no.2
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• pp.293-304
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• 2018

In spite of a growing number of recent studies that indicate students are coming to view scientists with more varied images, the stereotypical image of scientists remains in many students' minds. In this study, the authors explore how college students change their perceptions of science and scientists through the use of a documentary that focuses on scientists' daily lives, including laboratory life, and their emotional ups-and-downs. We analyzed 109 college students' essays on perceptions about scientists after watching the documentary. As a result, 64.2% of the college students declared that there was a change in their perception of scientists. The students' new perceptions of science and scientists are as follows: 1) scientists undergo emotional ups-and-downs just like any normal person; 2) scientists experience numerous failures while researching; 3) science does not have a fixed answer and scientists undertake research with creativity; 4) scientists conduct research in collaboration, but also in highly competitive environments; 5) scientists are often frustrated with their socio-economic status. The students' previous perceptions on science and scientists were mainly stereotypical ones that have been reported in previous studies. In addition, of the other college students who did not change their perceptions, the majority declared that they have new perceptions such as 1) - 5). Only a small percentage of students (7.3%) had unchanged stereotypical perceptions. These results are interpreted as that college students relatively easily change their stereotypical images of scientists after watching the documentary but, alternatively, the results can be interpreted that the most stereotypical images of college students are not perceptions that form a deep impression, but rather they are simply depictions of representative images of scientists given from outside sources (e.g. the mass media and school).

• Journal of the Korean Society of Radiology
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• v.18 no.3
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• pp.187-201
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• 2024

Osteoporosis is a major health issue globally, often remaining undetected until a fracture occurs. To facilitate early detection, deep learning (DL) models were developed to classify osteoporosis using abdominal computed tomography (CT) scans. This study was conducted using retrospectively collected data from 3,012 contrast-enhanced abdominal CT scans. The DL models developed in this study were constructed for using image data, demographic/clinical information, and multi-modality data, respectively. Patients were categorized into the normal, osteopenia, and osteoporosis groups based on their T-scores, obtained from dual-energy X-ray absorptiometry, into normal, osteopenia, and osteoporosis groups. The models showed high accuracy and effectiveness, with the combined data model performing the best, achieving an area under the receiver operating characteristic curve of 0.94 and an accuracy of 0.80. The image-based model also performed well, while the demographic data model had lower accuracy and effectiveness. In addition, the DL model was interpreted by gradient-weighted class activation mapping (Grad-CAM) to highlight clinically relevant features in the images, revealing the femoral neck as a common site for fractures. The study shows that DL can accurately identify osteoporosis stages from clinical data, indicating the potential of abdominal CT scans in early osteoporosis detection and reducing fracture risks with prompt treatment.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.3
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• pp.211-221
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• 2009

With recent trends of super-tallness, atypical plan shapes and zoning constructions in high-rise buildings, a structural stability of the building under construction is arising as a key issue for design and construction plan. To ensure the structural stability under construction, the differential column shortening of vertical members, the lateral displacement of tower frames, and differential settlement of raft foundation by unbalanced distributions of a tower self-weight before the completion of a lateral load resisting system should be checked by construction sequence analysis, which should be performed by systematic combinations with structural health monitoring, construction compensation program, and construction panning. This paper presents the scheme of zone-based construction sequence analysis by using the existing commercial analysis program, to check the stability of high-rise building under construction. This scheme is applied to 3-dimensional structural analysis for a real high-rise building under construction. The analysis includes real construction zoning plans and schedules as well as creep and shrinkage effects and time-dependent properties of concrete. The simplified construction sequence and assumed material properties were continuously updated with the change on construction schedule and correlations with in-situ measurement data.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.1
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• pp.1-8
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• 2018

The purpose of this study is to implement modeling by applying the parametric technique to the atypical trusses of rigid retractable large space structures. The retractable large space structure requires a lot of time and skill in modeling nonlinear shapes or generating, interpreting, and reviewing many models by alternative. To solve these problems, we introduce firstly parametric modeling tool, secondly, we analyze the connection of atypical three-dimensional trusses of a rigid retractable large-space structure, and finally model it as parametric components of the developed trusses. Therefore, it is a future study to make effective modeling of the openable roof by developing the components that can realize the modeling of the truss classified by the opening and closing method, respectively.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.7 no.2
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• pp.120-126
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• 2014

Acromioclavicular (AC) joint cyst is an uncommon presentation around the shoulder joint that is usually associated with chronic rotator cuff pathology and degenerative AC joint arthritis. Understanding the underlying pathophysiology of the shoulder joint is essential for appropriate interpretation of the AC joint cyst, assistance in determining the therapeutic strategy, and prevention of complications after treatment. We present a case of AC joint cyst with an aseptic fistula which was complicated by simple excision for recurred AC joint cyst after multiple aspirations. This case revealed a massive rotator cuff tear involving supraspinatus, infraspinatus, and subscapularis tendon on ultrasonography. We also reviewed the clinical approach and treatment options to be considered for its pathogenesis in the literature.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.1 no.1
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• pp.64-72
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• 2008

Compression neuropathy around elbow and wrist are one of the common disturbing problems in the upper extremity. The understanding of normal nerve architectures and pathophysiologic changes in compression neuropathy is important to interpret the ultrasonographic images correctly. Compression neuropathies have characteristic ultrasonographic imaging features of flattened nerve at compression and hypoechoic swollen nerve with loss of fascicular patterns at proximal segments. Dynamic ultrasonographic imagings on motion can show dymanic subluxation of ulnar nerve and medial head of triceps muscle over the medial epicondyle in snapping triceps syndrome. Dynamic compression of median nerve also can be visualized in pronator teres syndrome by dynamic imaging studies. A quantitative measures of cross sectional area or compression ratio can be helpful to diagnose compression neuropathies, such as carpal tunnel syndrome or cubital tunnel syndrome. With the clinical features and electeophysiologic studies, the untrasonographic imagings are useful tool for evaluation of the compression neuropathies in the upper extremities.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.2
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• pp.159-166
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• 2014

Beatrix Farrand was America's first female landscape architect and Dumbarton Oaks in Washington, D.C., USA site of her best known garden design. The purpose of this study is to identify characteristics of the American Neoclassical tendencies in the early 1900s and Farrand's style through an analysis of Dumbarton Oaks. The results of analysis indicated that although Dumbarton Oaks was influenced by many European classic gardens, the garden has the unique style which reflects regional contexts and culture based on the philosophy of arts and crafts movement, The major characteristics of the late Neoclassical style in America can be summarized as follows. First, A series of terraced gardens were connected by paths and stairways and natural terrain was preserved as much as possible. Second, the formal and informal style coexist and the symmetric and asymmetric forms are well-balanced throughout the garden. Third, selection of plant materials and planting methods, influenced by both classical gardens and the Arts and Crafts style in UK, are in harmony with the space configuration and shape.

• Tunnel and Underground Space
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• v.17 no.5
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• pp.381-388
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• 2007

The regular RC structures have been transformed into irregular RC structures by alternate load of RC structures during explosive demolition. Numerical simulation programs have contributed to a better understanding of large displacement collapse behavior during explosive demolition, but there remain a number of problems which need to be solved. In this study, the 1/5 scaled 1, 3 and 5 stories RC structures were designed and fabricated. To consider the collapse possibility of upper dead load, fabricated RC structures were demolished by means of felling method. To observe the collapse behavior of the RC structures during felling, displacement of X-direction (or horizontal), displacement of Z-direction (or vertical) md relative displacement angle from respective RC structures were analyzed. Finally explosive demolition on the scaled RC structures using felling method are carried out, collapse behavior by felling method is affected by upper dead load of scaled RC structures. Displacement of X and Z direction increases gradually to respective 67ms and 300ms after blasting. It is confirmed that initial collapse velocity due to alternate load has a higher 3 stories RC structures than 5 stories.