• Journal of the Korean Institute of Rural Architecture
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• v.10 no.1
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• pp.19-26
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• 2008

1) Lishu village is located in a riverside of an upper Tu-men river. Since an upper tream of Tu-men river is narrow and easy to pilot a boat, early in the past, it facilitated the form of the village near to the North Korea. 2) As for elevation, it consisted of only doors, but as time goes by, windows were made. So windows and doors were appearing much in the elevation. In 1970s', elevations are constructed in various ways; in 1980, attributed to brick housing, the elevations become much more diverse; from 1990, symmetrical elevation was revealed which consists of one door and two windows in each side of a door after 2000, the structure of the housing restored of 1930s' style which contained one window in Jungji and 1970s' style consisting of 3 windows, moreover, many free-style elevations appeared to be commercial use.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.12
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• pp.964-969
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• 2002

The flexural vibration of laminated composite beams with passive constrained layer damping has been investigated to design structure with maximum possible damping capacity. The equations of motion are derived for flexural vibrations of symmetrical, multi-layer laminated beams. The damping ratio and modal damping of the first bending mode are calculated by means of Iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations.

• Steel and Composite Structures
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• v.29 no.4
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• pp.493-508
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• 2018

Free vibration analysis of super-elliptical composite thin plates was investigated. Plate is formed by symmetrical quasi-isotropic laminates. Rayleigh-Ritz method was used for parametric analysis based on the governing differential equations of Classical Laminated Plate Theory (CLPT). Simply supported and clamped boundary conditions at the periphery of plates were considered. Parametric study was performed for the effect of different lamination type, aspect ratio, thickness and super-elliptical power on natural frequencies. Convergence study and validation of isotropic case were achieved. A number of design parameters like different dimensions, structure systems, panel sizes, panel thicknesses, lamination sequences, boundary conditions and loading conditions must be considered in the production of composite ships. The number of possible combinations practically may be so high that a parametric study should be carried out in order to determine the optimum design parameters rapidly during the preliminary design stage. The use of Rayleigh-Ritz method could make this parametric study possible. Thereby it might be decreasing the consumption of time, material and labor. Certain results for some different super-elliptical powers presented in tabulated form in Appendix for designers as well.

• Advances in aircraft and spacecraft science
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• v.7 no.2
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• pp.151-168
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• 2020

The present study deals with the repair of composite structures by bonding composite patches. The composite structure is a carbon/epoxy laminate with stacking sequence [45/-45/0/90]S. The damaged zone is simulated by a central crack and repaired by bonding symmetrical composite patches. The repair is carried out using composite patches laminated from the same elemental folds as those of the cracked specimen. Three-dimensional finite element method is used to determine the energy release rate along the front of repaired crack. The effects of the repair technique used single or double patch, the stacking sequence of the cracked composite patch and the adhesive properties were highlighted on the variations of the fracture energy in mode I and mixed mode I + II loading.

• Journal of Auto-vehicle Safety Association
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• v.6 no.1
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• pp.33-40
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• 2014

In this study the cylinder liner deformation which is one of the most influencing factors in a diesel engine oil consumption was performed by the finite element analysis on the basic designed structure consisting of the cylinder block, head and liners under the conditions of assembly, thermal and gas loads. Compared with a large number of other cylinder blocks showing remarkable harmonic orders of the liner distortion, results are excellent. Namely. the higher harmonic order amplitudes of the radial liner deformation amount to 1 ~ 2㎛ maximally. The main reason lies in the relatively large wall thickness of the liner which amounts to 8.2% of the bore diameter. Besides, a very stiff and symmetrical cylinder block design in combination with a bolt force introduction approximately 1.5mm below the block top deck have a further share on these results. Therefore excellent low oil consumption can be expected.

• Journal of the Korean housing association
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• v.27 no.2
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• pp.43-51
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• 2016

The purpose of this study was to search the architectural forms including the residence plan and wooden structure and the measuring unit in building sites named Bang in Gyeong_Ju, the capiatal of Silla dynasty. It includes the following three historic sites: JaMaeJung-ji, the east district of HwangLyong-sa (S1E1) and InWang-dong historic site. Especially, the data from excavating and studying the east district of HwangLyong-sa were very precious and meaningful. The results were as follows: 1) There are individual characteristics at the sites of JaMaeJung-ji, the east district of HwangLyong-sa and InWang-dong. 2) It is assumed that the builldings of the east district of HwangLyong-sa had most various types of plan and various types of wooden structures. 3) There were various types of wooden structures like as symmetrical or asymmetrical style, regular columnar or irregular columnar style and a third purlin location or a forth purlin location. 4) This study also showed there's a high probability that buildings at Bang sites had been built by the Tang dynaty scale. In Silla dynasty, there was similar tendency to BackJe Dynasty in the way that measuring unit changed according to the times.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.7 s.98
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• pp.661-670
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• 2005

In this paper, the microstrip $90^{\circ}$ hybrid to provide -3dB coupling and $90^{\circ}$ phase difference at broadband frequency range of 2 to 6 GHz is designed. This proposed hybrid is composed of 3-section. The two outside section are realized by symmetrical edge coupled lines, but on the other hand the middle section consists of VIP(Vertically Installed Planar) circuit. The ground part of VIP circuit is partially removed to get tight coupling, particularly. This hybrid is easy to realize due to microstrip structure and has good holing flexibility by taking advantage of VIP circuit as a control point of optimization. The proposed hybrid provide satisfactory performance as compared with simplicity of structure and fabrication first of all.

• Journal of Ocean Engineering and Technology
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• v.24 no.5
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• pp.8-15
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• 2010

The flow around a two-dimensional, rectangular cylinder that is freely falling in a channel was simulated using the immersed boundary method with direct forcing to determine the interactions between the fluid and the structure. The results of the present study were in good agreement with previous experimental results. Regardless of the H/L ratio (where H and L are the height and width of the rectangular cylinder, respectively), the flow structures had essentially the same pattern as the two symmetrical circulations that form about the horizontal center of the cylinder, with those centers located at each lateral position near the wake. When the cylinder approaches very close to the bottom, a jet-like flow appeared between the bottom of the rectangular cylinder and the channel. When the jet-like flow goes through the channel, surrounding fluids are sucked into this jet, forming the secondary vortices.

• Journal of Ocean Engineering and Technology
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• v.17 no.2
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• pp.72-76
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• 2003

This paper presents the design concept and operation results of float-off for FSO (340,000 DWT Class, ELF AMENAM KPONO Project) built on the ground, without dry dock facilities. It was the first attempt to build FSO, completely, on the ground and launch it using DBU (Double Barge Unit, which was connected by rigid frame structure.) The major characteristics of FSO, which are similar to general VLCC type hull, including topside structure, weigh 51,000 metric ton. In order to have sufficient stability during the deck immersion of DBU, while passing through a minimum water plane area zone, proper trim control was completed with LMC (Load Master Computer). The major features of the monitoring system include calculation for transverse bending moment, shear force, local strength check of each connector, based on component stress, and deformation check during the load-out and float-off. Another major concern during the operation was to avoid damages at the bottom and sides of FSO, due to motion & movement after free-floating; therefore, adequate clearances between DBU and FSO were to be provided, and guide posts were installed to prevent side damage of the DBU casings. This paper also presents various measures that indecate the connector bending moment, damage stability analysis, and mooring of DBU during float off.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.12
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• pp.2541-2549
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• 2002

In order to study the vibration characteristics of fluid-structure interaction problem, two rectangular plates coupled with bounded fluid were investigated. Experimental modal analyses were carried out to extract the modal parameters of the system. Additionally. finite element modal analyses performed using a commercial computer code, ANSYS. The FEM solutions were compared with the experimental solutions to verify the finite element model. As a result, the comparison between the experiment and FEM results showed excellent agreement. The transverse vibration modes, in-phase and out-of-phase, were observed alternately in the fluid-coupled system. The thickness effect of the plates on the fluid-coupled natural frequencies and mode shapes was investigated for two different cases with the identical thickness and the unequal thickness. It was found that the coupled natural frequencies increase with the thickness for the identical plates regardless of the mode phase. The experimental and the finite element analysis results showed that the out-of-phase mode shapes were deviated from the symmetrical mode shapes in the plate transverse direction fur the unequal plate thickness case.