• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.281-286
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• 2007

An engineering design problem involving Multi-Disciplinary Analysis(MDA) generally requires a large amounts of computing time for the entire design process, and therefore it is essential to introduce a Multiple Processor System (MPS) for reducing the computing time. However, when applying conventional parallel processing techniques, all of the CAE S/W requited for the MDA should be installed on all the servers making up MPS because of characteristic of MDA and it would be a great expense in CAE S/W licenses. To solve this problem, we propose a Weight-based Multiqueue Load Balancing algorithm for a heterogeneous MPS where performance of servers and CAE S/W installed on each server are different of each other. To validate the performance, a Computational experiments comparing the First Come First Serve algorithm and our proposed algorithm was accomplished.

• Journal of architectural history
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• v.20 no.6
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• pp.115-129
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• 2011

The bracket sets which are supporting the weight of the roof, has to meet both requirements which are structural functions and act as an ornamental element. Therefore the bracket sets differ in many types from time and space and has done an important role in the history of architecture with many studies being presented. The first form of the bracket set has been found in the bronze table relics in zhong shan wang ling (中山王陵). Through the Eastern Han dynasty (A.D. 25-220) it became more specific in the shique (石闕) and huaxiangshi (畵像石) in the Han dynasty (206 B.C.-A.D. 220). Afterwards, as Buddhism was introduced to China, the bracket construction techniques shown in the Mogao Caves, Yungang Grottoes, and Longmen Grottoes has given much help for understanding the building techniques of wooden architecture. Especially the Xia-ang structure seen in the Mogao caves shows a vast development in wooden structure and a typical building would be the main hall of Fo Guang Shan monastery in Mt. Wutaishan from the Tang dynasty (A.D. 618-907). This accumulated techniques is inscribed in the 'Ying Zao Fa Shi (營造法式)' wooden structure designs which was published during the Northern Song dynasty (A.D. 960-1127) and many buildings were constructed following this technique after the publication. During this period, it is assumed that Baek-jae (B.C.18-A.D.660) in the Korean peninsula also used the Xia-ang technique, but there havn't been many studies on this field. In this thesis it is introducing the development of the building techniques and structural features of the Xia-ang wooden architecture during the Tang and Song dynasty.

• Journal of Korean Society of Steel Construction
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• v.17 no.1 s.74
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• pp.103-113
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• 2005

In the present study, the Direct Inelastic Design (DID) for steel structures developed in the previous study was improved to expand it applicability. The proposed design method can perform inelastic designs that address the design characteristics of steel structures: Group member design, discrete member sizes, variation of moment-carrying capacity according to axial force, connection types, and multiple design criteria and load conditions. The design procedure for the proposed method was established, and a computer program incorporating the design procedure was developed. The design results from the conventional elastic method and the DID were compared and verified by the existing computer program for nonlinear analysis. Compared with the conventional elastic design, the DID addressing the inelastic behavior reduced the total weight of steel members and enhanced the deformability of the structure. The proposed design method is convenient because it can directly perform inelastic design by using linear analysis for secant stiffness. Also, it can achieve structural safety and economical design by controlling deformations of the plastic hinges.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.156-162
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• 2017

Recently, researches on High-Volume Fly ash Cement(HVFC), which is replacing high portion of cement to fly ash, have been actively conducted to reduce $CO_2$ formation. Though HVFC has various advantages, low strength development in early ages is pointed out as the biggest problem in the application of fly ash. In order to overcome such limitations, this study investigated the hydration and compressive strength characteristics of HVFC paste depending on the fly ash content with the mixing ratio varying from 0 to 80 %. Experimental results show that the HVFC paste with low water-binder ratio can overcome the limitation of low compressive strength at early ages. Also, from the result of heat flow delay, 50 % of fly ash weight ratio was the critical point of the filler effect.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.11-18
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• 1991

Stiffened plate structure, which is generally used in the various structural design to develope the load carrying capacity, is classified in two groups; one is the plate stiffened with stiffeners, the other is corrugated plate. In the studies on those structures, the studies on the stiffened plates with stiffeners have been much studied with both quantities and qualities according to requirements of the minimum-weight structural design and the development in many industrial fields, especially automobile, ship and aerospace fields, but the studies on the corrugated plates are undeveloped in comparison with the stiffened plates, and also the analytical stiffness on the corrugated plates remains as the imperfect. In the present studies, the analytical method on the stiffness of corrugated plates made by folding is proposed, and the stiffness equation of corrugated plates with some angle is derived and generalized. The purpose of the present study is to contribute to the design of corrugated plates and to determine the optimum aspect ratio for parameters that decide the aspect of corrugated plates.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.5
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• pp.543-550
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• 2007

As an emerging materials in construction fields, FRP(fiber reinforced polymer) has been used in many area of civil engineering for its light weight and high strength. In this study we chose the 2nd Jindo-Bridge as a prototype, and evaluate effect of replacing steel components to FRP components through simplified 3D linear analysis. Static and modal analysis are done and the analysis results are compared with steel case analysis. From the static analysis results, the maximum stress of each component and maximum displacement of middle span are compared. Due to the reduction of deadload, the FRP structure causes less deflection than the original steel structure and from the reduced section (cable) analysis we confirmed the previous result. The occurrence wind velocity of flutter is compared by the frequency ratio.

• Composites Research
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• v.15 no.2
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• pp.11-17
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• 2002

The piezoelectric thin film sensor can be used to interpret variations in structural and material properties, e.g. for structural integrity monitoring and assessment. To illustrate one of this potential benefit, PVDF (polyvinylidene fluoride) film sensors are used for monitoring impact damage in Gr/Ep composite panels. Both PVDF film sensors and strain gages are attached to the surface of Gr/Ep specimens. A series of impact tests at various impact energy by changing impact mass the height are performed on the instrumented drop weight impact tester. The sensor responses are carefully examined to predict the onset of impact damage such as indentation, matrix cracking, and delamination, etc. Test results show that the particular waveforms of sensor signals implying the damage initiation and development are detected above the damage initiation impact energy. As expected, the PVDF film sensor is found to be more sensitive to impact damage initiation event than the strain gage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1887-1895
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• 2013

In this study, physical experiments were performed in a two-dimensional wave flume to investigate the hydraulic and structural performance of a SFT model. The experiments were made by generating regular waves of different heights and periods under various conditions of buoyancy to weight ratio (BWR) and water depth as well. Through the analysis of the experimental data, it was clarified that the sway and heave motions of the tunnel body linearly increased with wave height and period. In contrast, the roll motion was rather insignificant unless wave height and period were comparatively large as the design wave. Similarly proportional relationship with respect to wave height and period was obtained in case of the maximum tensile force acting on the tension legs and the wave loads on the tunnel body. Regarding the change of water depth or BWR conditions, generally decreasing trend was obtained according to increase of water depth but decrease of BWR for both of the magnitudes of structural behaviors or wave loadings on the SFT structure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.6
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• pp.699-705
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• 2012

The role of a seat belt in a vehicle is to protect the driver from injury when a crash occurs. However when a large crash occurs, the driver slips forward and receives a strong impact. To prevent this situation, improvement of seat belts is essential. In this study, the new concept of a dynamic locking tongue (DLT) for seat belts is developed. The DLT device is used to reduce the impact to the driver's chest by tightening the webbing, so the driver is protected from severe injury in a large crash. First, a finite element model of the DLT device is created using SAMCEF and structural analysis is conducted with boundary conditions similar to those found in experiments. Then, the stress in the DLT device can be calculated. Second, the shape of the DLT device is optimized using the response surface analysis method in order to minimize the stress and weight. The validity of the optimization of the DLT device is verified using structural analysis.

• Transactions of the KSME C: Technology and Education
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• v.4 no.2
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• pp.123-130
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• 2016

Unitex is widely used for the floor structure of urban railway vehicles because it shows good structural safety and heat insulation, has long life, and lowers the cost owing to easy installation. However, in spite of these merits, Unitex has a limit to the sound insulation performance, which is very important in vehicle structure. It shows a sound transmission loss considerably lower than the mass law value, which indicates the sound insulation performance per unit weight. Recently, railway vehicle manufacturers and Unitex supplier have tried to improve the sound insulation performance of Unitex, but meaningful results have not been achieved yet. Through the industry-university collaborative research, we propose structural improvement methods to increase the sound transmission loss by more than 5dB and we then verify the effect by performing experiments.