• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.104-104
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• 2001

Purpose： In this study, we investigated the possible motor pathways of hemiplegic stroke patients usin combined TMS and BOLD fMRI approach and evaluated the correlation between TMS a fMRI methods. Method： Four subjects, who demonstrated left hemiplegia after stroke, are included. TMS was performed using a Dantec Mag2 stimulator (Dantec Company, USA) in single puls mode with figure eight-shaped coil. Following TMS localization, The BOLD T2＊-weight images were acquired with echo planar imaging sequence (TR = 1.2 sec, TE = 60 msec, and flip angle = 90). Motor activation was studied by means of a repetitive fing flexion-extension task. The stimulation protocol comprised 10 cycles of alternating activati and rest (10 images per cycle). Total 60 cycles were performed and each cycle take abou 1.5 sec. The resulting images were then analyzed with STIMULATE (CMRR, U, o Minnesota) to generate functional maps using a student t-test (p < 0.0005) and cluste analysis.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.2
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• pp.58-64
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• 1989

Plastic instability in uniaxial tension of commercial purity Al has been studied with the emphasis of effects of thickness in cold worked specimens and recrystallized specimens. The thickness change gave rise to change in stress state and the amount of strain localization in specimen after diffuse necking. Therefore the thickness of speci- men could control modes of plastic instability. Regardless of recrystallized or cold worked state, the necking mode changed from diffuse necking to local necking, at about 1.5 .approx. 2 mm in thickness.

• The Journal of the Acoustical Society of Korea
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• v.15 no.1E
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• pp.39-44
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• 1996

Matched field localization schemes often show a high sensitivity to acoustic variabilities due to mismatch between assumed and actual environments. In this paper, we focus on the effect of source motion or Doppler on matched field processing (MEP). to accomplish this, MFP is extended to treat a moving source problem with normal mode description of the sound field. the extension involves both the temporally nonstationary and spatially inhomogeneous nature of the sound field generated by a time-harmonic point source moving uniformly in a stratified oceanic waveguide. It is demonstrated that the impact of source motion can be significant to MEP although the velocity of a moving source is much smaller than the sound velocity of the oceanic waveguide. In addition, a criteria for minimizing the effect of Doppler on MFP is discussed.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.4
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• pp.355-361
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• 2012

This paper presents an experimental study on the detection and location of nonlinear scattering source due to the presence of fatigue crack in a laboratory specimen. The proposed technique is based on a combination of nonlinear elastic wave spectroscopy(NEWS) and time reversal(TR) focusing approach. In order to focus on the nonlinear scattering position due to the fatigue crack, we employed only one transmitting transducer and one receiving transducer, taking advantage of long duration of reception signal that includes multiple linear scattering such as mode conversion and boundary reflections. NEWS technique was then used as a pre-treatment of TR for spatial focusing of reemitted second harmonic signal. The robustness of this approach was demonstrated on a cracked specimen and the nonlinear TR focusing behavior is observed on the crack interface from which the second harmonic signal was originated.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.485-490
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• 2008

Under localization developing for the control valve of the safety grade Q Class 1 which is established in the atomic power plant followed ASME Code and important parts (Body, Yoke, Bonnet, Actuator) design and produced. In order to verify this analyzed the earthquake stress of AOV. AOV the above of 33Hz occurred from fIrst mode, the earthquake stress occurred from inside the yield strength of the material.

• Structural Engineering and Mechanics
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• v.33 no.3
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• pp.325-337
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• 2009

Structural damage detection, damage localization and severity estimation of jacket platforms, based on calculating modal strain energy is presented in this paper. In the structure, damage often causes a loss of stiffness in some elements, so modal parameters; mode shapes and natural frequencies, in the damaged structure are different from the undamaged state. Geometrical location of damage is detected by computing modal strain energy change ratio (MSECR) for each structural element, which elements with higher MSECR are suspected to be damaged. For each suspected damaged element, by computing cross-modal strain energy (CMSE), damage severity as the stiffness reduction factor -that represented the ratios between the element stiffness changes to the undamaged element stiffness- is estimated. Numerical studies are demonstrated for a three dimensional, single bay, four stories frame of the existing jacket platform, based on the synthetic data that generated from finite element model. It is observed that this method can be used for damage detection of this kind of structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.249-252
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• 2006

When concrete is subjected to uniaxial compression, the failure process is normally initialed from a localized zone. The localization of failure governs structural behaviors of concrete. In this paper, the compressive strength and failure behavior of recycled coarse aggregate concrete with different replacement level of recycled coarse aggregates are investigated using acoustic emission(AE). AE characteristics of concrete were investigated during the entire loading period. For these purpose, four recycled coarse aggregate replacement level (i.e 0%, 30%, 60% and 100%) were considered in this paper. Result from this study show AE signal, AE method can apply to investigate a compressive failure mode according to recycled coarse replacement level.

• Journal of Veterinary Clinics
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• v.20 no.4
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• pp.519-522
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• 2003

An appearance of herniated intervertebral disc into thoracolumbar vertebral canal was evaluated in two patients using computed tomography (CT). Before CT scanning, plain radiography and myelography were performed in both cases. CT images were compared to those of myelography. Dogs were positioned in sternal recumbency under inhalation anesthesia and transverse slices with 2 mm thickness were obtained around thoracolumbar region. The transverse CT images were examined using both vertebral and spiral window mode. The most common findings on CT images were loss of vertebral canal epidural fat, bulging of vertebral canal disc margins, displacement of spinal cord and flatted vertebral canal. Whereas, narrowed intervertebral disc space and simple extradural pattern were the main findings on plain and contrast radiographs. CT imges showed the extent of the herniated disc lesion, type II intervertebral disc hernation, and the displacement of spinal cord in detail in both occations. It is considered that degree and precise localization of the intervertebral disc herniation and subtle lesion of spinal cord could be identified accurately using computed tomography.

• Culinary science and hospitality research
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• v.16 no.4
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• pp.15-27
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• 2010

As most companies in the world are much interested in the overseas market as well as in the domestic market, many Korean food service enterprises came to focus on extending their branches to the overseas market. However, lack of business strategies including market research, marketing strategies, localization, etc. has made them continue to fail in market entry. The purpose of this study is to develop entry mode of determinants of Korean food service enterprises, considering their characteristic factors and environment factors in the overseas market. To do this, companies which have a head quarter in Korea and over 2 year business experience in the overseas market were chosen and used for a self-administered questionnaire survey. Statistical processing, including descriptive statistics, logistic regressing analysis, and multi regression analysis using an SPSS/PC 12.0 statistical package were conducted The result is as follows. First, explanation suitability was 85% of the entry mode in the overseas market. Second, as business size was smaller, product differentiation was higher, and CEO's will for success in the overseas market was higher, independent entry mode in the overseas market was likely to he chosen. Lastly, as the uncertainty of demand and trade barrier were lower, and a sociocultural gap was smaller, independent entry mode in the overseas market was likely to be chosen.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.1
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• pp.81-89
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• 2012

This study propose the vibration-based damage monitoring scheme for steel girder bolt-connection member by using wireless acceleration sensor node. In order to achieve the objective, the following approaches are implemented. Firstly, wireless acceleration sensor node is described on the design of hardware components and embedded operation software. Secondly, the vibration-based damage monitoring scheme of the steel girder bolt-connection member is described. The damage monitoring scheme performed global damage occurrence alarming and damage localization estimation by the acceleration response feature analysis. The global damage alarming is applied to the correlation coefficient of power spectral density. The damage localization estimation is applied to the frequency-based damage detection technique and the mode-shape-based damage detection technique. Finally, the performance of the vibration-based damage monitoring scheme is evaluated for detecting the bolt-connection member damage on a lab-scale steel girder.