• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.979-990
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• 2010

Although a centrifuge model test is performed with scaled models, it has a lot of advantages compared with usual scale model tests, for the reproduction of stress levels equal to a full scale test is possible. At the beginning of the Daewoo Institute of Construction Technology, a servo-motor-driven single axis actuator was introduced and has been in use with a geo-centrifuge. However, for variety of experiments and construction stage simulation, various apparatuses have been developed, such as a vacuum generator, a lateral actuator for tidal power simulation, a gravel hopper and a sand drainer for filled-up ground, and a water level controller. The apparatuses have been manufactured with enough strength and durability to be operated under specific g levels. This paper presents the properties of the apparatuses and the results of the tests performed with those.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1017-1023
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• 2022

Past research shows that the construction of new infrastructure accelerates economic growth in the region by attracting more people and commodities. However, the previous studies only considered large-scale infrastructures such as sea-cross bridges and channel tunnels. There is a paucity of literature on regional infrastructure and its impact on socio-economic indicators. This paper explores the impact of new bridge construction on the human population, particularly focusing on regional bridges constructed during the 2000s in the state of Georgia. The human population at a county level was selected as a single socio-economic factor to be evaluated. A total of 124 cases were investigated as to whether the emergence of a new bridge affected the population change. The interrupted time series analysis was used to statistically examine the significance of population change due to the construction by treating each new bridge as an intervention event. The results show that, out of the 124 cases, the population of 67 cases significantly increased after the bridge construction, while the population of 57 cases was not affected by the construction at a significance level of 0.05. The 124 cases were also analyzed by route type, functional class, and traffic volume, but the results revealed, unlike large-scale infrastructure, that no clear evidence was found that a new bridge would bring an increase in the human population at a county level.

• 콘크리트학회논문집
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• 제16권6호
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• pp.867-873
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• 2004

It has been known that debonding failures between CFS(Carbon Fiber Sheet) and concrete in the strengthened RC beams are initiated by the peeling of the sheets in the region of combined large moment and shear forces, being accompanied by the large shear deformation after flexural cracks. These shear deformation effects are seldom occurred in small-scale model tests, but debondings due to the large shear deformation effects are often observed in a full-scale model tests. The premature debonding failure of CFS, therefore, must be avoided to confirm the design strength of full-scale RC beam in strengthening designs. The reinforcing details, so- called 'U-Shape fiber wrap at mid-span' which wrapped the RC flexural members around the webs and tension face at critical section with CFS additionally, were proposed in this study to prevent the debonding of CFS. Other reinforcing detail, so called 'U-Shape fiber wrap at beam end' were included in this tests and comparisons were made between them.

• 대한토목학회논문집
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• 제41권6호
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• pp.745-750
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• 2021

최근 미세먼지에 대한 국민들의 불안감이 증가함에 비산먼지에 대한 관심이 증가하고 있다. 비산먼지는 도로재비산먼지 다음으로 건설현장에서 많이 발생하는데 이 중 대부분을 차지하는 소규모 현장은 비산먼지 관련 규정이 없어 제대로 된 관리가 이뤄지지 않고 있는 실정이다. 이에 본 연구에서는 소규모 현장 비산먼지 관리 규정 수립에 기여하고 비산먼지 저감방안을 마련하고자 서울시 소규모 현장에서 발생하는 비산먼지를 측정 및 분석을 진행했다. 소규모 현장에서 발생하는 비산먼지의 시간별 변동을 확인했고 담장과 난간 뒤에서 측정했을 때 상대적으로 농도가 낮은 것을 통해 비산먼지 저감방안으로 간이 펜스 설치 방안을 제시했다.

• 한국안전학회지
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• 제24권6호
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• pp.111-118
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• 2009

As the construction project gets bigger in scale, the actual construction itself is becoming more complex. The construction accidents occupy 26.18 percent of total death disaster according to the accidents report in 2007. It is the highest figure among the entire industry, and it shows how serious the construction accident is. In order to reduce accidents occurred in the construction industry, we should find the accident characteristics of construction workers by age. In this study, we investigated 589 cases of fatal accidents, and classified them by trades, type of works, the things that caused the accident, how they occurred, and size. We then identified accident characteristics for each group by analysing them in accordance with workers age. The result of analysis showed that in carpenter and common laborer, the number of death accidents increased as the workers age increased. Another characteristics were that the number of death accidents increased as the age increased in finishing work and reinforced concrete construction and in a smaller-scale businesses, respectively. Common labor was the trade with the highest number of death accidents and the laborers of 50 age or higher in age in finishing working type were the most vulnerable to death accidents.

• 건축역사연구
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• 제30권4호
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• pp.79-90
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• 2021

Since its construction in the late 14th century, Hanyangdoseong had been carried out three major repairs and reconstructions during the 500 years of the Joseon Dynasty. In addition to the large-scale construction, small-scale construction continued until King Gojong era. In particular, in the 18th century, systematic construction management was implemented by the craftsmen and the military participated in the renovation of Hanyangdoseong in earnest, and the construction methods also developed rapidly. In the early 18th century, new construction techniques were attempted in various sections of the reconstruction work, and gradually became a common technology for repairing Hanyangdoseong in the late 18th century. The purpose of this study is to examine the characteristics and period of changes in the 18th century's construction technique, when the rapid development of Hanyangdoseong took place. To this end, the excavation results related to Hanyangdoseong, the remaining city wall, and the inscribed stones were used to identify and demonstrate the characteristics and change of the construction method.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.247-248
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• 2021

Recently, the government is pursuing to reduce the serious accidents in most industries, including the construction industry, by enacting laws on punishment. The accident rate tends to be depended on the size and type of construction sites, and the accidents occur frequently due to inadequate implementation of safety management system and management standards, especially, in small and medium-sized sites. This study has performed the profiling of 265,000 accident cases on construction sites by attribute analysis such as the ratio of days lost to work, and pattern of days lost to work compared to the size of the construction. It turned out that the proportion of accident cases was high mainly in small-scale construction sites, and long-term labor losses occurred. Shortly, it is necessary to establish an institutional standard for applying a realistic safety management cost calculation and management system centered on small-scale sites. Therefore, this study is expected to be used as fundamental data or guideline for developing a customized safety management and accident prevention system for a worker reflecting the conditions of a construction site in the future.

• 대한지리학회:학술대회논문집
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• 대한지리학회 2006년도 연례 학술대회
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• pp.37-38
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• 2006

• Computers and Concrete
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• 제31권1호
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• pp.9-21
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• 2023

The published studies usually used analytical method, numerical methods or experimental method to determine the stress-strain state and displacement of the single-layer or multi-layer curved shell types, but with a small scale model. However, a full scale multi-layer doubly curved concrete shell roof model should be researched. This paper presents the results of the experiment and simulation analysis involving stress-strain state, sliding between layers, the formation and development of the full scale double-layer doubly curved concrete shell roof when this shell begins to crack. The results of the this study have constructed the load-sliding strain relationship; strain diagram; stress diagram in the shell layers; the N_x, N_y membrane force diagram and deflection of shell. Thisresults by experimental method on a full scale model of concrete have clarified the working of multi-layer doubly curved concrete shell roof. The experimental and simulation results are compared with each other and compared with the Sap2000 software.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1243-1244
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• 2022

In recent years, the growing interest in off-site construction has led to factories scaling up their manufacturing and production processes in the construction sector. Consequently, continuous large-scale site monitoring in low-variability environments, such as prefabricated components production plants (precast concrete production), has gained increasing importance. Although many studies on computer vision-based site monitoring have been conducted, challenges for deploying this technology for large-scale field applications still remain. One of the issues is collecting and transmitting vast amounts of video data. Continuous site monitoring systems are based on real-time video data collection and analysis, which requires excessive computational resources and network traffic. In addition, it is difficult to integrate various object information with different sizes and scales into a single scene. Various sizes and types of objects (e.g., workers, heavy equipment, and materials) exist in a plant production environment, and these objects should be detected simultaneously for effective site monitoring. However, with the existing object detection algorithms, it is difficult to simultaneously detect objects with significant differences in size because collecting and training massive amounts of object image data with various scales is necessary. This study thus developed a large-scale site monitoring system using edge computing and a small-object detection system to solve these problems. Edge computing is a distributed information technology architecture wherein the image or video data is processed near the originating source, not on a centralized server or cloud. By inferring information from the AI computing module equipped with CCTVs and communicating only the processed information with the server, it is possible to reduce excessive network traffic. Small-object detection is an innovative method to detect different-sized objects by cropping the raw image and setting the appropriate number of rows and columns for image splitting based on the target object size. This enables the detection of small objects from cropped and magnified images. The detected small objects can then be expressed in the original image. In the inference process, this study used the YOLO-v5 algorithm, known for its fast processing speed and widely used for real-time object detection. This method could effectively detect large and even small objects that were difficult to detect with the existing object detection algorithms. When the large-scale site monitoring system was tested, it performed well in detecting small objects, such as workers in a large-scale view of construction sites, which were inaccurately detected by the existing algorithms. Our next goal is to incorporate various safety monitoring and risk analysis algorithms into this system, such as collision risk estimation, based on the time-to-collision concept, enabling the optimization of safety routes by accumulating workers' paths and inferring the risky areas based on workers' trajectory patterns. Through such developments, this continuous large-scale site monitoring system can guide a construction plant's safety management system more effectively.