• Computational Structural Engineering
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• v.11 no.1
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• pp.191-204
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• 1998

The general formulation for free vibration and stability analysis of unsymmetric thin-wared space frames is presented in case where the shear deformation effects are neglected. The kinetic and total potential energies are derived by applying the extended virtual work principle, introducing displacement parameters defined at the arbitrarily chosen axis and including warping deformation and second order terms of finite semitangential rotations. In formulating the finite element procedure, cubic Hermitian polynomials are utilized as shape functions of the two node space frame element. Mass, elastic stiffness, and geometric stiffness matrices for the unsymmetric thin-walled section are evaluated, and load-correction stiffness matrices for off-axis distributed loadings are considered. In order to illustrate the accuracy and practical usefulness of this formulation, finite element solutions for the free vibration and stability problems of thin-walled beam-columns and space frames are presented and compared with available solutions.

• Cross-Cultural Studies
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• v.49
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• pp.33-58
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• 2017

As a living space, house constitutes a good part of inhabitants' life, making the rhythm of life. This rhythm tends to be reflected into the house, establishing a sort of intercommunications between the house and its inhabitants. Becoming a living element, the house can endow the writer with literary resources. It is interrelated with its inhabitants. Thus, Duras' work preserves many invisible and fusional traces of links between her characters and the house. With her writing, the house displays important traces of life, with which a body of meaning is to be formed. It implies habits, imprints, links, and so on. Here, its projection into the imaginary also takes place for our writer. With this perspective in view, Duras is supposed to objectify her characters as physical and imaginary bodies. This introduces the passage from the real to the imaginary and vice versa. Unknown stories hidden behind the living places can come to manifest themselves through her writing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.211-217
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• 2019

In an complicated battlefield environment, information from enemy's camp is an important factor in carrying out military operations. For obtaining this information, the number of UAVs that can be deployed to the mission without our forces' loss and at low cost is increasing. Because the mission environment has anti-aircraft weapons, mission space is needed for UAV to guarantee survivability without being killed. The concept of Configuration Space is used to define the mission space considering with range of weapons and detect range of UAV. UAV must visit whole given area to obtain the information and perform Coverage Path Planning for this. Based on threats to UAV and importance of information that will be obtained, area that UAV should visit first is defined. Grid Map is generated and mapping threat information to each grid for UAV path planning. On this study, coverage conditions and path planning procedures are presented based on the threat information on Grid Map, and mission space is expanded to improve detection efficiency. Finally, simulations are performed, and results are presented using the suggested UAV path planning method in this study.

• Design Convergence Study
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• v.15 no.2
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• pp.169-184
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• 2016

Using geospatial information in the early design phase is crucial because it requires considerable time, money, and effort. We use VWorld, part of the National Spatial Information Distribution system provided by the Korean Ministry of Land, Infrastructure and Transportation, for providing geospatial information to building designers. We provide methods to adopt VWorld geospatial information to building design and develop plugins for a BIM authoring tool to transform and construct necessary BIM data in a user-friendly format. BIM users are benefitted from extra design information supplied from sibling disciplines such as urban design. GIS users are benefited by feedback building information continuously supplied from building projects based upon standard GIS coordinates. It is clear that an architectural designer with BIM tool can save time and efforts to obtain the geospatial information related a project using the developed system as result of this research.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.472-482
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• 2023

The grid-type or room-and-pillar method is applied for the purpose of mining horizontally buried minerals. In this study, design and pilot test were performed to apply the room-and-pillar method which uses natural rock as a rock pillar to the construction of underground space. The area where the pilot test was conducted was in stone mine and had good rock conditions with an appropriate depth (about 30 m) to apply the pilot test. The pilot test site was selected by reviewing accessibility and ground conditions and then site construction was performed through detailed ground investigation and design. The pilot test was designed with a column shape of 8×8 m and a cross-section of 8×12 m. The blasting pattern was determined through test blasting at the site, and blasting of 3 m excavation with 89 holes was performed. Through field observations, the average width of 12.5 m and the average height of 8.3 m were measured. Therefore, it is possible to proceed similar to the cross-sectional shape considered in the design.

• Journal of Cadastre & Land InformatiX
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• v.54 no.1
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• pp.103-115
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• 2024

Trilateral adjustment can complement the problem of transforming cadastral maps into World Geodetic Coordinate system. First, it is possible to determine adjusted coordinate of common points that match each other over a wide area. Second, calculations that focus on specific points can be performed. Third, a solution that maintains the shape of the regional network can be obtained through constraints. Thus, the point coordinates can be determined appropriately for the survey system. In addition, heterogeneous survey results that span regions with different coordinate origins can be calculated on a single origin coordinate. This improves the efficiency of the workflow in tranforming cadastral maps into World Geodetic Coordinate System.

• 한국지구물리탐사학회:학술대회논문집
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• 2004.08a
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• pp.25-48
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• 2004

Structures show the phehomena of deformation and lowering of function with time-lapse by artificial environments and changes of geotechnical conditions or accumulation of initial deformation elements. This study aims the structural assessment of cultural property, Chum-Sung-Dae, located in Kyeongju city, Korea. It was built about 1,300 years ago, and has undergone deformation and ground-subsidence with time-lapse. Non-destructive evaluation techniques were applied to the Chum-Sung-Dae, to protect it from survey Because of this reason, 3D precise laser scanning surveying system was applied to measure the exact size of Chum-Sung-Dae, displacement and declining angles. Geophysical exploration also was applied to study the subsurface distribution of geotechnical parameters or physical properties. Natural frequencies were measured from real and model of Chum-Sung-Dae to study the dynamic characteristics of vibration and/or earthquake load and stiffness of structures.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1301-1307
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• 2011

Electrosurgical knee wand (EKW) is a high-frequency thermocautery instrument and is often used for coagulation, ablation, excision, and extirpation of knee ligaments and tissues. In order to maximize the success rate, ease, and safety of knee surgery using EKW and radiofrequency ablation, it is necessary to ensure that the EKW selectively approaches the lesion with utmost accuracy and safety. The key feature of this instrument is its excellent maneuverability. Hence, the authors constructed a tensile spring model based on a shape memory alloy (SMA), which exhibits the shape memory effect. This model can be used in knee surgery as it is considered the most biocompatible femorotibial surgical actuator. The changes in external temperature with current and the thermoelectric characteristics of the SMA were investigated. The relationship between the restoring force and the typical stroke (TS) in response to the conditions in the SMA tensile spring design were evaluated. In conclusion, as the diameter of the SMA tensile spring decreased, the maximum temperature increased. The strain in the actuator caused a stable and proportional increase in the force and induced current for up to 15s, but this increase became very unstable after 30s. Moreover, the relationship between the current and the TS was more stable than that between the current and the restoring force.

• Korean Journal of Optics and Photonics
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• v.29 no.4
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• pp.166-172
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• 2018

In this paper, we propose a new method to predict a mirror's surface deformation due to the stress of moisture release by a coating in the environment of outer space. We measured the surface deformation of circular samples 50 mm in diameter and 1.03 mm thick, using an interferometer. The results were analyzed using Zernike fringe polynomials. The coating stress caused by moisture release was calculated to be 152.7 MPa. This value was applied to an analytic model of a 1.25 mm thickness sample mirror, confirming that the change of surface deformation could be predicted within the standard deviation of the measurement result ($78.9{\pm}5.9nm$). Using this methodology, we predicted the surface deformation of 600 mm hyperbolic mirror for the Compact Advanced Satellite, which will be launched in 2019. The result is only $2.005{\mu}m$ of focal shift, leading to 2.3% degradation of modulation transfer function (MTF) at the Nyquist frequency, which satisfies the requirement.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.4
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• pp.39-48
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• 2020

This study examined the type, the structural shapes, and the representation of Sandae, which was the stage for traditional performing arts and constructed for the purpose of imperial processions, ritual ceremonies, banquets, etc. from the Goryeo Dynasty to the Late Joseon Dynasty, and the implications of Seokgasan, which was built in the same era. First, through the history and meaning of Sandae, it was confirmed that Sandae has a homogeneity with Seokgasan, which attempted to imitate the shape of "Mountain" in the outer space. The construction of Sandae was deeply related to the tradition of famous mountains. This is consistent with the fact that 'Famous mountains and lakes" in China was symbolically replicated on the Seokgasan in the front yard of the "Cheongyeongak" in the Goryeo Dynasty. Second, Sandae and Seokgasan differed in their structural shapes, materials, and production methods, but they were used as a stage background for national events by constructing in the shape of the mountain, and appeared in various types. It can be seen that the interest in gardens and art of those days has resulted in various formative expressions of nature through the shape and symbolic meaning of the Sandae that mimics the mountain. Third, it is presumed that the square pond with lotus flowers, which is believed to have been located in the center of the garden of Shin Jaehyo's old house, and the Sugak and Seokgasan adjacent to it were not only elements of the garden, but also functioned as a background for the training and performance stage of Shin Jaehyo's students.