• Proceedings of the KSME Conference
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• 2002.08a
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• pp.705-706
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• 2002

Hemodynamics of the TPLS(Twin Pulse Life Support System) is numerically investigated to delineate the possibility of hemolysis in blood. Computational method employing finite element algorithm is utilized to solve the blood flow of the sac squeezed by moving actuator. We assume that the blood flow interacts with the sac material which is activated by the rigid body motion of the actuator. Valve dynamics at the ends of the sac is simplified as on/off type motion. We compute the transient viscous flow in the two-dimensional geometry of the blood sac. Incompressible laminar flow is simulated on the assumption of Newtonian fluid. Blood velocity has a step gradient near the throat of the sac formed by the moving actuator. According to the decrease of the gap size of blood passage, the magnitude of shear stress in the blood is dramatically increased. Numerical solutions show that the maximum value of shear stress in the blood flow in TPLS is relatively smaller than that of the roller type ECLS.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.642-649
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• 2006

In order to recognize a situation from a environment which provides an intelligent service, we propose state-transition based situation modeling which is suitable for a low computing power and restricted resources like embedded systems, and we designed its application to a situation-action converter(SAC)which is consist of two parts; situation detector recognized wanted situations and action generator generated various control actions. Then, we implemented a situation manager for smart scheduler service by using a SAC which is installed to a ARM processor based embedded Linux evaluation board.

• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.421-425
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• 2003

In this study the occlusion of dural-sac. the outer membrane of spinal cord in the lumbar region. was quantitatively analyzed using one motion segment finite element model. Occlusion was quantified by calculating cross sectional area change of dural-sac for different compressive impact duration (loading rate) due to bony fragment at the posterior wall of the cortical shell in vertebral body. Dural-sac was occluded most highly in the range of 8∼12 msec impact duration by the bony fragment intruding into the spinal canal. $\Delta$t = 400 msec case 4 % cross sectional area change was calculated. which is the same as the cross sectional area change under 6 kN of static compressive loading.

• Investigative Magnetic Resonance Imaging
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• v.23 no.4
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• pp.367-373
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• 2019

Yolk sac tumors are rare malignant germ cell neoplasms that usually arise from the gonads. Extragonadal yolk sac tumors (EGYSTs) frequently occur in the mediastinum in post-pubertal females. EGYSTs in the pelvis are extremely rare, and to date, only thirteen cases have been reported in the English literature. Among them, the primary EGYST of the pelvic peritoneum in post-pubertal females has only been reported in ten cases. The present case describes a 26-year-old female diagnosed with primary peritoneal yolk sac tumor located in the rectouterine pouch. We report clinical and tumor imaging features, including ultrasound, computed tomography (CT), magnetic resonance images (MRI), positron emission tomography-computed tomography (PET-CT), and present a review of the literature.

• Journal of the Korean Society of Visualization
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• v.20 no.2
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• pp.45-54
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• 2022

We analyzed the low wall-shear stress area in the intracranial aneurysm that occurred at an anterior communicating artery with a special emphasis on vortical structures close to the wall. We reconstructed the aneurysm model from patient CTA data. We assumed blood as an incompressible Newtonian fluid and treated the blood vessel as a solid wall. The pulsatile boundary condition was applied at the inlet of the anterior cerebral artery. From the instantaneous flow field, we computed the histogram of the wall-shear stress over the aneurysm wall and found the low wall-shear stress event (< 0.4 Pa). This extreme event was due to the low wall-shear stress area that occurred at the daughter sac. We found that the merging of two vortices induced the low wall-shear stress area; one arises from the morphological characteristics of the daughter sac, and the other is formed by a jet flow into the aneurysm sac. The latter approaches the daughter sac, which ultimately leads to the strong ejection event near the daughter sac.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.153-156
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• 2004

Spatial Audio Coding (SAC)은 낮은 대역폭에서 다채널/다객체 오디오 신호를 전송하기 위해 제안된 기술이다. 본 논문에서는 MPEG 에서 SAC 기술의 평가 방법으로 채택된 Multi-Stimulus test with Hidden Reference and Anchor (MUSHRA) 실험 절차에 대해서 설명한다. 또한 제 69 차 MPEG 회의에서 제안된 4 개 기관의 SAC 기술에 대한 청취실험을 수행하고 그 결과를 분석한다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.10a
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• pp.435-438
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• 1997

This paper presents the process generating a SAC(Sectional Area Cure) by using ASMOD(Adaptive Spline Modeling of Observation Data). That is, we define SACs of real ships as B-spline curves by a hybrid cure approximation(which is the combination method of a B-spline fitting method and a genetic algorithm) and accumulate a database of control points. Then we let ASMOD learn from the correlation principal dimensions with control points.

• Journal of Plant Biology
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• v.6 no.2
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• pp.3-6
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• 1963

As a part of embryological studies of Panax ginseng, megasporangium and megagametophyte formations were investigated. Ovule is found to be auatropous. Small-sized nucellus is surrounded by thick layered single integument. As the embryo sac develops, the nucellus along with some parts of the inner epidermis of integument disintegrates and completely disappers at flowering stage. Embryo sac takes the type of typical Polygonum although antipodal cells disappear and polar nuclei fuse to form secondary nucleus before fertilization. Mature embryo sac consists of egg apparatus and large secondary nucleus lying adjacent to the egg. Besides the normal ovule, tiny incomplete ovule develops near the base of style. Frequently two normal ovules are formed in a single locule. Chromosome number counted is PMC is n=24.

• Structural Engineering and Mechanics
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• v.52 no.2
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• pp.275-290
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• 2014

In this paper, Simple Adaptive Control (SAC) method is used to mitigate the detrimental effects of earthquakes on MR-damper equipped structures. Acceleration Feedback (AF) is utilized since measuring the acceleration response of structures is known to be reliable and inexpensive. The SAC is simple, fast and as an adaptive control scheme, is immune against the effects of plant and environmental uncertainties. In the present study, in order to translate the desired control force into an applicable MR damper command voltage, a neural network inverse model is trained, validated and used through the simulations. The effectiveness of the proposed AF-based SAC control system is compared with optimal H2/LQG controllers through numerical investigation of a three-story model building. The results indicate that the SAC controller is substantially effective and reliable in both undamaged and damaged structural states, specifically in reducing acceleration responses of seismically excited buildings.

• ETRI Journal
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• v.27 no.5
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• pp.635-638
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• 2005

Spatial audio coding (SAC) is an extremely high compact representation of encoded multi-channel audio material. This paper suggests a multi-channel audio service in the terrestrial digital multimedia broadcasting (T-DMB) system using a novel SAC tool, which is called a virtual source location information (VSLI)-based SAC tool. Intensive experiments are presented to evaluate the validity of the proposed VSLI-based SAC tool, and prototypical systems are also presented to demonstrate the reliability of the proposed multi-channel T-DMB system in real applications.