• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.3 s.333
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• pp.9-16
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• 2005

The mobility in strained Si inversion layer on $Si_{1-x}Ge_x$ is calculated considering a quantum effect(subband energy and wavefunction) in inversion layer and relaxation time approximation. The quantum effect in inversion layer is obtained by using self-consistent calculation of $Schr\ddot{o}dinger$ and Poisson equations. For the relaxation time, intravalley and intervalley scatterings are considered. The result shows that the reason for the enhancement in mobility as Ge mole fraction increases is that the electron mobility in 2-폴드 valleys is about 3 times higher than that of 4-폴드 valleys and most electrons are located in 2-폴드 valleys as Ge mole fraction increases. Meanwhile, for the phonon-limited mobility the fitting to experimental data, Coulomb and surface roughness mobilities are included in total mobility, Deformation potentials are selected for the calculated effective field, temperature, and Ge mole fraction dependent mobilities to be fitted to experimental data, and then upgraded data can be obtained by considering nonparabolicity in Si band structure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.3
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• pp.59-65
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• 1991

Failure criteria for asphalt concrete pavements are developed combining the AASHTO design equation and the multi-layered elastic theory. Thickness range including typical layer thicknesses of four-layer Korea highway structures are employed for pavement structure models. Total of 2430 pavement models with different layer thicknesses and moduli are analyzed. Models with crushed stone and asphalt stabilized base courses are equally included in the analysis. Number of load repetition and the maximum tensile strain at the bottom of asphalt layer are computed from the AASHTO design equation with terminal PSI=2.5 and multi-layered elastic computer program, SINELA, respectively. Failure criteria are developed through the regression analysis. From the analysis, failure criteria for the asphalt concrete pavements with 50% and 95% reliability levels are developed. It is found that the failure criterion of 95% reliability level gives similar results with existing fatigue failure criteria whose terminal performance condition is crack development when compared in a graphical form an equation to estimate failure criterion for a specific reliability level is also proposed.

• Explosives and Blasting
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• v.37 no.4
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• pp.1-9
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• 2019

In this study the applicability of a Digital Image Correlation (DIC) method was investigated by measuring the displacement and vibration of rock pillar due to underground mining blasting. When combined with a high speed photography technology, the DIC method provides an excellent photographic image processing ability that can be used to convert the evolving full-field surface properties of structures to 2D or 3D set of coordinate values. The measured coordinate sets are then used to calculate the displacement, strain, and velocity of the target structure. This technique is widely used in science and engineering, and continuously finds its new application areas. In this study, the DIC system and the conventional seismograph were compared for their ability to measure the displacement and vibration produced by blasting. In the field test both methods showed similar results. Thus, it is concluded that the DIC method is feasible to measure the ground displacements and vibrations from blasting.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.9
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• pp.25-32
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• 2006

In this study, the characteristics of filament wound composite/aluminum ring specimens were investigated at cryogenic temperature. The ring specimens were manufactured using carbon fibre and Type B epoxy resin which had been developed for cryogenic use. As a result of measuring thermal strains at -150℃, it was found that compressive thermal stress was induced in composite part on the contrary, tensile thermal stress in aluminum part which was about 32% of yield stress and in turn, caused aluminum to be yielded at lower load level. In addition, Thermal strains which resulted from finite element analysis showed good agreement with those of the experiment. After 6 mechanical loading cycles had been applied to the ring specimen at -150℃, tensile tests were performed at -150℃ using a split disk fixture. As a result, it was shown that composite strength in a liner-composite tank structure which is for the use of cryogenic propellant tank would be decreased by auto-frettage pressure which is applied to it.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.4
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• pp.437-448
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• 2000

In this study, a numerical analysis method for soil-pile interaction in frequency domain problem is presented. The total soil-pile interaction system is divided into two parts so called near field and far field. In the near field, beam elements are used lot a pile and plain strain finite elements for soil. In the far field, dynamic fundamental solution for multi-layered half planes based on boundary element formulation is adopted lot soil. These two fields are coupled using FE-BE coupling technique. In order to verify the proposed soil-pile interaction analysis, the dynamic responses of pile on multi-layered half planes are simulated and the results are compared with the experimental results. Also, various numerical analyses of piles considering different conditions of soil-pile interaction system are performed to examine the dynamic behavior of the system. It has been found that the developed method which satisfies the radiation conditions of multi-layered half planes can be applied to various structure systems effectively in frequency domain.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.223-229
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• 2017

Europe, the US and Japan have acquired test results on impact coefficient for a long time and applied it to equipment design to secure safety of structures. However, Korean enterprises use the impact factor held by advanced business to design equipment as it is difficult for them to obtain it through tests. In this paper, NX/NASTRAN, was used to perform static load analysis and impact load analysis of a PCB Handler, semiconductor test equipment, and the result was employed to study how to calculate the impact coefficient with the finite element analysis. The calculation method was applied to the JIS(Japanese Industrial Standard), and the impact coefficient of the PCB handler was calculated as 1.27 for the sudden start or stop. The impact coefficient generated by the analysis is expected to make a great contribution to the industry as it can be used to improve the equipment structure and develop on existing equipment in the future.

• Journal of Advanced Navigation Technology
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• v.23 no.4
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• pp.273-280
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• 2019

There are many studies that use structure health monitoring to reduce maintenance costs for aircraft and to increase aircraft utilization. Many studies on FBG sensors are also being conducted. However, if the FBG sensor is installed inside the composite, voids will occur between the layers of the composite, resulting in signal split problem. In addition, the FBG sensor is not affected by electromagnetic waves, but will produce electromagnetic noise caused by electronic equipment during post-processing. In this paper, to reduce the error caused by these noises, the stationary wavelet transform, which has the characteristics of movement immutability and is efficient in nonlinear signal analysis, is presented. And in the above situation, we found that noise rejection performance of stationary wavelet transform was better compared with the wavelet packet transform.

• Composites Research
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• v.34 no.2
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• pp.101-107
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• 2021

Composite structures have components and joints. Theses connections or joints can be potentially weak points in the structure. The failure mode of the composite bolted joint is designed as a bearing failure mode for structural safety. The load-displacement relation exhibits bearing failure mode shows a nonlinear behavior after the initial failure and progressive failure behavior. In order to accurately predict the failure behavior of composite bolted joints, this study modified the shear damage variable calculation process in the existing progressive failure analysis model. The results of the bearing stress-bearing strain of the composite bolted joint were predicted using the modified progressive failure analysis model, and the modified model was verified through comparison with the previous progressive analysis model.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.2
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• pp.77-82
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• 2023

The structural analysis module is an essential part of any integrated structural system. Diverse integrated systems today require, from the analysis module, efficient real-time responses to real-time input such as earthquake signals, extreme weather-related forces, and man-made accidents. An integrated system may also be for the entire life span of a civil structure conceived during the initial conception, developed throughout various design stages, effectively used in construction, and utilized during usage and maintenance. All these integrated systems' essential part is the structural analysis module, which must be automated and computationally efficient so that responses may be almost immediate. The finite element method is often used for structural analysis, and for automation, many effective finite element meshes must be automatically generated for a given analysis. A computationally efficient finite element mesh generation scheme based on the r-h method of mesh refinement using strain deviations from the values at the Gauss points as error estimates from the previous mesh is described. Shape factors are used to sort out overly distorted elements. A standard cantilever beam analyzed by four-node plane stress elements is used as an example to show the effectiveness of the automated algorithm for a time-domain dynamic analysis. Although recent developments in computer hardware and software have made many new applications in integrated structural systems possible, structural analysis still needs to be executed efficiently in real-time. The algorithm applies to diverse integrated systems, including nonlinear analyses and general dynamic problems in earthquake engineering.

• The Journal of the Korea Contents Association
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• v.12 no.2
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• pp.163-172
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• 2012

The hero is in the TV drama's long. TV drama Heroes historical blip on the public's desire to delegate to the body and its functions as an intensive, which have a specific period drama that soars like a hero's welcome and it is the communication between the viewer a sense of contemporary popular devices that can be separated. This study today, the various cultural areas which are becoming popular in Japan's historical hero 'Yoshitune' a heroic drama, the hero's narrative research stories In the analysis occupies an important place in the Joseph Campbell's 17 steps of heroic narrative, based on analysis achetype and adaptation. Campbell, 11 of the 17 stage dramas to apply different levels, and the omission of two steps, and shows a variation of the four stages, in order to relaunch the popular culture as the content selection and a constant strain was able to find out that you need.