• Korean Journal of Biological Psychiatry
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• v.10 no.2
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• pp.147-158
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• 2003

Objective:The differences of various neurocognitive functions, including attention, memory, motor function, and higher cognitive function were compared between PTSD patients and normal control subjects. Also, correlation with PTSD symptom severity and neurocognitive functions were evaluated between PTSD patients and normal control subjects. Method:We assessed the neurocognitive functions by computerized neurocognitive test(CNT) batteries. The visual continuous performance test(CPT) and digit span test, finger tapping test and Wisconsin card sorting test(WCST) were executed. The Impact of Event Scale-Revised(IES-R) was used in the evaluation of the severity of PTSD. Result:The PTSD patients showed significantly impaired neurocognitive performance in all of the items, compared with normal control subjects. The relation between impairment in neurocognitive functions and symptom severity showed significant correlations. Conclusion:These results imply that PTSD patients have impaired neurocognitive functions concerning with specific brain areas, especially the frontal area. For the thorough evaluation of further neurocognitive functions, more detailed evaluation items of neurocognitive functions and brain imaging studies are necessary in the future study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.840-846
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• 2007

This paper investigates the dynamic behavior of a HDD spindle system due to the imperfect roundness of a rotating shaft. The shaft of a spindle motor rotates with eccentricity by the unbalanced mass of the rotating part. The eccentricity generates the run-out of a spindle motor which results in the eccentric motion of a rotating part. Roundness of a shaft affects this motion which limits the memory capacity of a HDD. This research proposes a modified Reynolds equation for the coupled journal and thrust FDBs to include the variable film thickness due to the roundness. Finite element method is used to solve the Reynolds equation for the pressure distribution. Reaction forces and friction torque are obtained by integrating the pressure and shear stress, respectively. The dynamic behavior is determined by solving the equations of a motion of a HDD spindle system in six degrees of freedom with the Runge-Kutta method to characterize the motion of a rotating part. This research shows that the roundness of a rotating shaft causes the excitation frequency with integer multiple of a rotating frequency.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.852-858
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• 2007

This paper investigates the dynamic characteristics of a tilted HDD spindle system with fluid dynamic bearings (FDBs). Tilting motion of a HDD spindle system may be caused by improper manufacturing tolerance, such as imperfect cylindricity between shaft and sleeve of FDBs, imperfect perpendicularity between shaft and thrust as well as the gyroscopic moment of the unbalanced mass of the rotating part. Tilting motion may result in the instability of the HDD spindle system and it may increase the disk run-out to limit memory capacity. This research proposes a modified Reynolds equation for the coupled journal and thrust FDBs to include the variable film thickness due to the cylindricity and the perpendicularity. Finite element method is used to solve the Reynolds equation for the pressure distribution. Reaction forces and friction torque are obtained by integrating the pressure and shear stress, respectively. The dynamic behavior is determined by solving the equations of a motion of a HDD spindle system in six degrees of freedom with the Runge-Kutta method to study whirling and tilting motions. This research shows that the cylindricity and the perpendicularity increase the tilting angle and whirl radius of the rotor.

• Journal of Sensor Science and Technology
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• v.23 no.5
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• pp.314-319
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• 2014

Here, we review the various methods for the preparation of vanadium dioxide ($VO_2$) films and nanowires, and their potential applications to the sensors such as gas sensor, strain sensor, and temperature sensor. $VO_2$ is an interesting material on account of its easily accessible and sharp Mott metal-insulator transition (MIT) at ${\sim}68^{\circ}C$ in the bulk. The MIT is also triggered by the electric field, stress, magnetic field etc. This paper involves exceptionally sensitive hydrogen sensors based on the catalytic process between hydrogen molecules and Pd nanoparticles on the $VO_2$ surface, and fast responsive sensors based on the self-heating effects which leads to the phase changes of the $VO_2$. These features will be seen in this paper and can enable strategies for the integration of a $VO_2$ material in advanced and complex functional units such as logic gates, memory, FETs for micro/nano-systems as well as the sensors.

• Computers and Concrete
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• v.11 no.1
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• pp.51-61
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• 2013

This paper describes earthquake response of the Arhavi Highway Tunnel its geometrical properties, 3D finite element model and the linear time history analyses under a huge ground motion considering soil-structure interaction. The Arhavi Highway Tunnel is one of the tallest tunnels constructed in the Black Sea region of Turkey as part of the Coast Road Project. The tunnel has two tubes and each of them is about 1000 m tall. In the study, lineartime history analyses of the tunnel are performed applying north-south, east-west and up accelerations components of 1992 Erzincan, Turkey ground motion. In the time history analyses, Rayleigh damping coefficients are calculated using main natural frequency obtained from modal analysis. Element matrices are computed using the Gauss numerical integration technique. The Newmark method is used in the solution of the equation of motion. Because of needed too much memory for the analyses, the first 10 second of the ground motions, which is the most effective duration, is taken into account in calculations. The results obtained 3D finite element model are presented. In addition, the displacement and stress results are observed to be allowable level of the concrete material during the earthquakes.

• Structural Engineering and Mechanics
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• v.17 no.3_4
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• pp.357-378
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• 2004

Nonlinear dynamic analysis of a reinforced concrete (RC) frame under earthquake loading is performed in this paper on the basis of a hysteretic moment-curvature relation. Unlike previous analytical moment-curvature relations which take into account the flexural deformation only with the perfect-bond assumption, by introducing an equivalent flexural stiffness, the proposed relation considers the rigid-body-motion due to anchorage slip at the fixed end, which accounts for more than 50% of the total deformation. The advantage of the proposed relation, compared with both the layered section approach and the multi-component model, may be the ease of its application to a complex structure composed of many elements and on the reduction in calculation time and memory space. Describing the structural response more exactly becomes possible through the use of curved unloading and reloading branches inferred from the stress-strain relation of steel and consideration of the pinching effect caused by axial force. Finally, the applicability of the proposed model to the nonlinear dynamic analysis of RC structures is established through correlation studies between analytical and experimental results.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.2
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• pp.23-34
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• 1998

This research proposes on effective analytical methodology for vertical vibration of three dimensional frame structures including slabs. The consideration of slabs, although allows more precise results, requires large amount of computer time and memory space due to the use of plane stress elements. In consideration of these problems, a method to properly manage nodal points and degrees of freedom is proposed based on matrix condensation technique. Also studied is the use of super elements to obtain fast and reliable results with simple input data when they are applied to conventional building structures.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.141-144
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• 2009

The purpose of this study is to develop the auxiliary rehabilitation device for a patient of spinal curvature. The adolescent diopathic scoliosis(AIS) must be treated by rehabilitation brace if Cobb angle is $20^{\circ}{\sim}40^{\circ}$. The rehabilitation brace is consist of 4 vest and 2 hinge parts(hinge and couple bar) that give a force to the ribs. But thin and light hinge parts for young patient failed easily because of unusual movement of the upper body. We studied optimum design and structural analysis of hinge parts when it distorted by tensile and bending force. The specimen of hinge parts were tested to evaluate the failure strength. And we attached circuits with memory and sensor detecting pressure and displacement to recoding stress in hinge parts. These data are used to alarm the patient to stop unusual movement and understand the load history.

• The Journal of Pediatrics of Korean Medicine
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• v.23 no.3
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• pp.241-262
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• 2009

Objectives This study is designed to investigate the effects of Jujadokseo-hwan on the brain ability and inducing oxidative stresses. Methods We measured the changes of regional cerebral blood flow and mean arterial blood pressure. Then we analyzed histological examination, immunohistochemistric response and anti-oxidant activity of Jujadokseo-hwan. Results 1. Treatment of Jujadokseo-hwan significantly increased regional cerebral blood flow but decreased mean arterial blood pressure. 2. Treatment of Jujadokseo-hwan-induced increase of regional cerebral blood flow was significantly inhibited by pretreatment with indomethacin (1 mg/kg, i.p.), an inhibitor of cyclooxygenase. 3. In histological examination through TTC stain, group I was no change, but group II showed that discolored in the most cortical part. Group III showed that decreased discolor in the cortical part. 4. In immunohistochemistric response of BDNF, group II showed that lower response effect. Group III showed that increase response effect. 5. Treatment of Jujadokseo-hwan increased proliferation rates of Glial cell effectively 6. Treatment of Jujadokseo-hwan accelerated proliferation rates of C6 cells in vitro. In addition, protective effects on cell death induced by paraquat, rotenone and hydrogen peroxide. In addition, activity of SOD were increased by treatment with Jujadokseo-hwan. Conclusions In conclusion, Jujadokseo-hwan can improve of the brain ability, learning ability, memory ability and induce ischemic brain injuries.

• Research in Community and Public Health Nursing
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• v.28 no.1
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• pp.98-106
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• 2017

Purpose: To understand the meaning of the lived experience with Person under train (PUT) for train or subway operators. Methods: The study was built on hermeneutic phenomenological themes from individual interviews of present-day train or subway operators in South Korea. Eight participants were selected to participate in the study. All qualitative data were analyzed using the heuristic guides of Van Manen. Results: Four fundamental lifeworld themes and eight sub themes emerged in the findings. The first theme of spatiality had'the place pressed by the darkness' and 'the train drags me there'. The second theme, corporeality had 'a foreboding fear', and 'debris of death that gets stuck in the whole body'. The temporality theme had'distorted time in chaos', and 'memory trapped in time'. Finally the last existential theme of relationality had 'intrapersonal encounter' and 'resentment and guilt'. Conclusion: The four existential lifeworld themes provided a framework for in-depth investigation of the operator's "lived experience." This leads to clear understanding of effects of PUT experience on related individuals. The findings imply that specific active nursing intervention strategies are necessary in order to treat affected train operators, and to prevent further issues in their work and private life.