• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.194-199
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• 2001

Lap splice in plastic hinge region is inevitable because of due to constructional joint between footing and column. R/C Circular columns with lap-splice in plastic hinge region are widely used in Korean highway bridges. In addition, these columns which constructed before the seismic design code have a number of structural deficiencies. It is, however, believed that there are not many experimental research works for nonlinear behavior of these columns subjected to earthquake motions. The object of this research is to evaluate the seismic performance of existing circular reinforced concrete bridge piers by the Quasi-static test. Existing reinforced concrete bridge piers were moderate seismically designed in accordance with the conventional provisions of Korea Highway Design Specification. This study has been performed to verify the effect of lap spliced longitudinal steel, confinement steel type and confinement steel ratio far the seismic behavior of reinforced concrete bridge piers. Quasi-static test has been done to investigate the physical seismic performance of RC bridge piers, such as displacement ductility, energy absorption, strength degradation etc.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1259-1267
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• 2008

One of the most important item for insuring the stability of ground in urban deep excavation site near by major structure such as subway is displacement control of earth retaining wall. The field monitoring system is classified by two types as manual system and automatic system. The application case of latter type of field monitoring is increased because real time measurement is possible in automatic system and that is correspondent with the recent constructional trend. Though the automatic monitoring system is more useful and advanced than manual monitoring system, accuracy of the system is not verified sufficiently. It was examined that the reliance of automatic monitoring system in this paper through the comparison of monitoring result obtained one of deep urban excavation site in which the each type of monitoring system was executed concurrently. Result of the examination is that the two types of monitoring system is generally alike in view of monitoring result, so the engineering reliance of automatic system was confirmed in case site. This study was researched in restricted one case site, so it is expected more precise analysis from security of more data monitored and progressive study.

• Journal of Korean Society of Steel Construction
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• v.26 no.6
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• pp.605-615
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• 2014

The purpose of this study is to propose an economic new type rib by applying plate stiffening methods of the corrugated plate and the honey-comb sandwich panel to the steel deck plate and comparing the new type rib with existing open and closed ribs. The trapezoidal corrugated type, ㄹ type, honey-comb type and ㅁ type ribs are considered as new type ribs and the moment and the steel volume are compared with that of open ribs and closed ribs. The results shows that the honey-comb type and ㅁ type ribs are good in aspects of economic feasibility and the ㅁ type is better than the honey-comb type. To make the ㅁ type rib applicable to the steel deck plate, the sensitivity analysis and parametric study are performed and the system to select the proper section under the particular stress condition is established. The closed rib of real bridges is compared with the ㅁ type rib of the proposed system and it is known that the new type rib is more economic. Therefore, more economic steel deck plates can be achieved by using the system proposed in this study for the plate stiffened with the new ㅁ type rib.

• Journal of Power Electronics
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• v.12 no.1
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• pp.208-214
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• 2012

This paper presents a novel approach based on the loci of instantaneous symmetrical components called "Wing Shape" which requires the measurement of three input stator currents and voltages to diagnose interturn insulation faults in three phase induction motors operating under different loading conditions. In this methodology, the effect of unbalanced supply conditions, constructional imbalances and measurement errors are also investigated. The sizes of the wings determine the loading on the motor and the travel of the wings while their areas determine the degree of severity of the faults. This approach is also applied to detect open circuit faults or single phasing conditions in induction motors. In order to validate this method, experimental results are presented for a 5 hp squirrel cage induction motor. The proposed technique helps improve the reliability, efficiency, and safety of the motor system and industrial plant. It also allows maintenance to be performed in a more efficient manner, since the course of action can be determined based on the type and severity of the fault.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.221-228
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• 2005

The economic growth brought the demand of bridge connected to island and land increasingly in Korea. Therefore, Civil engineer has faced a lot of problem to be considered such as structural stability, economic feasibility and constructional method. At the bridge site to be constructed, the depth of water is about 24m, the thickness of weathered rock overlaying bed rock is thicker than 36m. If open caisson foundation is supported in bed rock, the hight of foundation is about 60m. It is difficult to construct in these conditions. If open caisson foundation is supported in weathered rock, the size of the foundation should be increased. And If we apply the pile foundation, the higher construction cost will be needed. Under the circumstances, we need a new foundation type-composite foundation that is consisted of open caisson and cast-in-place piles. Because the design concept of composite foundation is not presented in Korea Bridge Design Standard, we are willing to clear the bearing behavior of composite foundation by numerical analysis in this paper.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.23-30
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• 2003

This paper analyzes the characteristic of utility connection type solar power generation system which it is available to connect the utility. And the operation characteristic of this system is compared and analyzed when it is operated in the real system. The constructional and operational problem were obtained by that result. Overcoming that defect is that finding the proper place to be well operated and to find the best place for getting the sunshine data. This method could increase the efficiency of the generation system. And more, current OS in operating system and monitoring management couldn't solve the problem so that improving OS and constructing data backup system should be implemented, This paper proposes the plan to solve that defect in the real system.

• Steel and Composite Structures
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• v.7 no.1
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• pp.53-70
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• 2007

This paper presents a analysis of the problem of optimal design of the beams with two I-type cross section shapes. These types of beams are simply supported and subject to pure bending. The strength and stability conditions were formulated and analytically solved in the form of mathematical equations. Both global and selected types of local stability forms were taken into account. The optimization problem was defined as bicriteria. The cross section area of the beam is the first objective function, while the deflection of the beam is the second. The geometric parameters of cross section were selected as the design variables. The set of constraints includes global and local stability conditions, the strength condition, and technological and constructional requirements in the form of geometric relations. The optimization problem was formulated and solved with the help of the Pareto concept of optimality. During the numerical calculations a set of optimal compromise solutions was generated. The numerical procedures include discrete and continuous sets of the design variables. Results of numerical analysis are presented in the form of tables, cross section outlines and diagrams. Results are discussed at the end of the work. These results may be useful for designers in optimal designing of thin-walled beams, increasing information required in the decision-making procedure.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.229-232
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• 2008

Researches on the steel-concrete composite girder filled with plain concrete have been being actively performed on the grounds that this type of girder has constructional, structural and aesthetical benefits. As a part of studies on the characteristics of inner shear connections in the concrete-filled steel-concrete composite girder with plain concrete, the confinement effect on the stiffness of inner shear connections was examined in this study. In the case of concrete-filled steel-concrete composite girder, it can be expected that the stiffness of shear connections may be increased in comparison with the case not confined. Therefore, the experimental studies were performed with the confinement effect as a parameter, and the results are discussed in this paper.

• Steel and Composite Structures
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• v.20 no.1
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• pp.21-41
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• 2016

Cold-formed steel structures are increasingly attractive due to their benefits of good mechanical performance and constructional advantages. However, this type of construction is still not fully exploited as a result of the acknowledged difficulties involved in forming construction-efficient and cost-effective connections. Furthermore, there is a lack of information on the structural behavior of the cold-formed steel connections. In this study, the research on various cold-formed steel connections was comprehensively reviewed from both fundamental and structural points of view, based on the available experimental and analytical data. It reveals that the current design codes and guidelines for cold-formed steel connections tend to focus more on the individual bearing capacity of the fasteners rather than the overall structural behavior of the connections. Significant future work remains to be conducted on the structural performance of cold-formed steel connection. In addition, extensive previous research has been carried out to propose and evaluate an economical and efficient connection system that is obtained from the conventional connecting techniques used in the hot-rolled industry. These connecting techniques may not be suitable, however, as they have been adopted from hot-rolled steel portal frames due to the thinness of the sheet in cold-formed steels. The review demonstrates that with the increasing demand for cold-formed steel constructions throughout the world, it is crucial to develop an efficient connection system that can be prefabricated and easily assembled on site.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.2
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• pp.70-81
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• 2013

In this study, the locational and constructional characteristics of Jukrimseowon, pavilion Imrijeong, and Palgwaejeong located in Nonsan, Ganggyung-eup were reviewed and the interrelation of these three places were studied through references including records of those days; Sagyeyonbo(沙溪年譜), Jukrimseowon dorok(竹林書院都錄), Imrijeonggi(臨履亭記), Jukrimseowon Myojeongbi(竹林書院廟庭碑), Namyurok(南遊錄). The result is as follows. Jukrimseowon enshrining Yukhyeon(六賢) is arranged as 'Hongsalmoon-Woisalmoon-Dongjae(憲章堂; Heonjangdang)' and 'LIbrary-Naesammoon(神門; shin moon)-Sau(竹林祠: Jukimsa)', excluding a lecture hall. In case of Sagye Jangsang Kim's Imrijeong(沙溪金長生) and Uam Shiyoel Song(尤庵宋時烈)'s Palgwaejeong respectively constructed 50 meters and 10 meters each away from Jurimseowon, detail designs such as scale, roofs, surface, windows, doors, and tablets as well as its prospect are nearly identified. Especially Taking Imrijeong and Palgwaejeong's locational conditions composed of rocks centered on Jukrimseowon, those are maintain the bilateral symmetry as much as possible and surround the shrine. It appeared that the Jukrimseowon's shrine enshrining Yulgok(栗谷) and Ugye(牛溪) was rebuilt during the reconstruction of auditoriums because of political conditions after the renovation of Kiing Injo and it was called as 'Hwangsanseowon(黃山書院)' with Imrijeong which was a lecture hall. It was an inevitable consequence to keep the bilateral symmetry which is a basic order of auditorium structure by maintaining and using Imrijeong and Palgwaejeong as a lecture hall of the auditorium after the reconstruction at least. Consequently, the desperate attempt to adjust the arrangement and visual imbalance of Imrijeong built with periodical differences and Hwangsanseowon resulted from the construction of shrine was Palgwaejeong built under Monggoibyuk of Hwansan Taken these circumstances together, Jukrimseowon is a 'shrine-centered auditorium' with characteristics of auditorium, constructed by integrating Imrijeong which was used as a lecture hall after the construction of shrine and Palgwaejeong repaired through the reconstruction. The construction of Palgwaejeong and the formative conformity with Imrijeong are assumed as an consequence intended for the compensation of Jukrimseowon's function and role as an auditorium. This study will provide an opportunity to focus on the auditorium and pavilion's complementary function as well as the Confucian and constructional functions by revealing the fact that pavilions were established as a complementary facility for the lecture hall of auditorium.