• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.11
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• pp.1105-1110
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• 2012

The spine is one of the most important skeletal joints, and it strongly affects the health of the musculoskeletal system. A normal spine has an S-shape, and it is very important to maintain this shape. Recently, spinal diseases such as low back pain have increased rapidly, especially among the elderly. Some of these diseases are caused by congenital spinal disorders and sporting and accident injuries as well as by bad postures. Improper spinal postures could generate excessive disc pressure, which is related to degeneration and pain. Therefore, in this study, we investigated the three-dimensional kinematic parameters of the thoraco-lumbar joint in several bad postures using a motion capture analysis technique. Different bad postures created a significant amount of flexion/extension, side bending, and axial rotation angle compared with neutral postures. Further study is necessary to investigate the disc pressure and ligament force due to the increase in joint rotation from the bad postures.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.4
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• pp.94-102
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• 1999

This paper is related with the compensation of communication channel characteristics using predistorter, and the considered characteristic is the additive noise, phase rotation and frequency selective fading which occurred in communication channel. Predistorter can minimize the effect of obstacle element which occured in channel at receiving side by transmitting the predistortion of signal after modulation, the coefficient of inverse electrical charateristic of communication channel is performed at transmitting side. For this purpose, the predistorter is designed by using Tricepstrum Equalization Algorithm which is adaptive equlizer algorithm, and the receiving side must transmit the probing signal to transmitting side. Using the probing signal, the transmitting side can obtain the inverse characteristic coefficient of communication channel, and this probing signal must be transmitted periodically. We assumed that the channel characteristic do not change during this one period. As a result of computer simulation, we confirmed that the performance of predistorter was fairly good as same as the adaptive equalizer, and this technique have a effectiveness that can be used in the forward channel of mobile communication in order to achieve high speed transmission.

• Journal of the Korean Society for Nondestructive Testing
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• v.37 no.1
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• pp.29-36
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• 2017

Recently, KTX (Korean Train Express) train stoppage accidents were mainly caused by malfunctioning equipment, aging and cracking of railway vehicles, crack breakages of brake disks, and breakages of brake disks. Breakage of brake disk can cause large-scale casualties such as high-speed collision and concern about derailment by hitting lower axle and wheel. Therefore, in this study, a brake disk with solid and ventilation type, which is the brake disk of a KTX train was modeled, and a dynamometer system was constructed to operate the disk. A Rayleigh wave was used to inspect the surface of the brake disk. An ultrasonic inspection module was developed for the brake disk by using a local immersion method due to the difficulty involved in ultrasonic inspection using an existing immersion method. In addition, the surface defects of the brake disk were evaluated using a dynamometer mock-up system and an ultrasonic inspection module of the brake disk.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.3 s.21
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• pp.41-51
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• 2002

Recently, many studies extracting the geography information using digital aerial image have been implemented. But it is very difficult that automatically recognizing objects using edge detection method on the aerial image, and so that work have practiced manually or semi-automatically. Therefore, in this study, we have removed impedimental elements for recognition using the image which overlapped the significant information bands of brightness-sliced aerial images, then have developed the algorithm which can automatically recognize and extract road information and we will try to apply that method when we develope a system. For this, first of all, we have developed the 'template conformal-transformation moving operator' for automatically recognizing crosswalk area from crosswalk band image and the 'window normal search algorithm' which is able to track road area based on long-side length of crosswalk, so that we have proposed the method that can extract directly the road information from the aerial image.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.8
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• pp.505-510
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• 2017

This paper presents a low-cost robotic device for shoulder rehabilitation, which is capable of treating various shoulder disabilities. A 3-DOF passive shoulder joint tracking module was designed to allow for translational motion of the shoulder joint center during arm swing, which is essential for natural shoulder movement. The weight of the user's arm and the device were compensated for by springs, to enable gravity-free shoulder motion. In order to reduce the device's cost, only one actuator was used, which can be aligned with the user's shoulder joint in various orientations. The device is capable of implementing five representative shoulder motions, including flexion/extension, abduction/adduction, horizontal abd/adduction, internal/external rotation, and oblique raise. The proposed low-cost shoulder rehabilitation robot is expected to provide effective rehabilitation for patients with various shoulder impairments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1247-1255
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• 2016

The safety and autonomous flight function of micro UAV or drones is crucial to its commercial application. The requirement of own building stable drones is still a non-trivial obstacle for researchers that want to focus on the intelligence function, such vision and navigation algorithm. The paper present a GCS using commercial drone and hardware platforms, and open source software. The system follows modular architecture and now composed of the communication, UI, image processing. Especially, lane-keeping algorithm. are designed and verified through testing at a sports stadium. The designed lane-keeping algorithm estimates drone position and heading in the lane using Hough transform for line detection, RANSAC-vanishing point algorithm for selecting the desired lines, and tracking algorithm for stability of lines. The flight of drone is controlled by 'forward', 'stop', 'clock-rotate', and 'counter-clock rotate' commands. The present implemented system can fly straight and mild curve lane at 2-3 m/s.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.47-54
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• 2008

Cost reduction requires lowering number of power devices used in the converter driving SRM. This is quite feasible in SRM drive systems than in other drive systems. This paper deals with analysis and simulation of a novel two phase SRM. A novel two phase SRM has high performance, self-starling capability, high efficiency, and low manufacturing cost. Additionally, the stator back iron does not experience any flux reversal as the flux is in the same direction whether phase A or B is excited leading to a greater reduction in core losses. The magnetic analysis and design considerations of the novel two phase SRM have been obtained by the finite element analysis (FEM).

• Journal of fish pathology
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• v.17 no.1
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• pp.21-28
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• 2004

In late summer of 2001, a new disease "overturn disease" occurred among mud loach (Misgurnus mizolepis) cultured in a farm Chonbuk Province. The fish exhibited a lethargic, erratic and spiral swimming at the water surface. Affected fish showed swollen abdomen with accumulation of air bubbles in the intestinal canal. The bubbles were much larger in the anterior part than in the posterior part. Hematological and histopathological examinations were done. No significant differences were found in RBC count, Ht value and Hb concentration between the diseased and the healthy fish. Gill filaments showed proximal hyperplasia of the respiratory epithelia and fusing of the gill lamella. Hemorrhage and necrosis occurred in the intestinal epithelia and within the lamina propria, and the mucosal epithelia were separated from the muscularis. Hepatocytes underwent atrophy. In the fish experimentally tied between the annal fin and the anus by a thread to confirm accumulation of air bubbles within intestine, accumulation of air bubbles was confirmed. This disease in mud loach appeared to be induced by circulatory disturbances in the intestinal wall owing to accumulation of air bubbles in the alimentary canal after fed high protein diet throughout all culturing period.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.9-9
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• 2020

하천공간은 홍수방어와 용수사용을 위한 수자원관리 측면의 공간에서 벗어나 국민들의 삶의 질 제고와 이용편익, 생활환경의 중심 공간으로 자리매김하고 있다. 국민의 하천에 대한 눈높이가 상승하고 있음에도 하천공간이 주는 여러 가치에 대해서는 학술적 검토가 미진하였으며, 그에 따라 정책에도 제한적으로 반영되고 있다. 본 연구에서는 설문조사, 요인분석 등을 통해 주민 입장에서 부여할 수 있는 하천의 다면적 가치를 식별하고 주민친화적 관리를 위한 성과지표를 개발하고자 하였다. 특히 본 연구가 개발하고자 하는 성과지표 체계는 기존 방식대로 객관화·정량화가 불가능한 주민의 정성적·주관적 만족도를 측정할 수 있는 지표를 개발하는 것에 목적이 있다. 먼저, 관련된 각종 선행연구 및 도로 등 타분야 사례, 일본 등 해외 사례 등을 종합하여 하천의 4가지 사업부문인 치수, 이수, 환경, 친수를 모두 포괄하는 지표체계안을 구축하였다. 다만 본 연구가 주민친화적 하천관리를 목적으로 하므로 상대적으로 환경·친수 부문 지표의 비중이 높았으며, 총 지표 개수는 25개로 도출하였다. 도출한 지표체계안을 바탕으로 주민 대상 설문조사를 실시하였으며, 요인분석법을 활용하여 지표체계를 재정리하였다. 요인분석법은 학술적·실무적으로 가장 널리 사용되는 PCA 추출법과 Varimax 회전법을 채택하였으며, KMO 및 Barlett's 검정법을 활용하여 자료 검정을 수행하였다. 그 결과, 하천 부문 주민만족 요인은 3가지로 나타났으며, 이를 각각 '최소친수기반요인', '안전·청결기반요인', '친수활동지원요인'으로 정의하였다. 요인 분석 결과를 바탕으로, 3개 영역, 6개 세부 영역, 24개 평가항목으로 구성된 성과지표 체계를 도출하였다. 마련된 성과지표의 항목별 중요도를 전국 대상 설문조사를 통해 분석한 결과, 영역 중에서는 '안전·청결기반요인'이 가장 중요한 것으로 나타났으며, 특징적으로는 CCTV, 장애·위험물 제거, 수질·공간청결성, 공공화장실 만족성 등이 중요한 것으로 나타났다. 또한 대전지역 국가하천과 지방하천을 사례지역으로 성과지표를 비교한 결과, 국가하천의 성과가 대체로 높게 나타났으며 '최소친수기반요인' 영역의 성과가 상대적으로 높은 것으로 나타났다.

• Progress in Medical Physics
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• v.14 no.2
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• pp.141-148
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• 2003

The purpose of this study is to evaluate the distribution of clusters and blood flow rate in ADHD SPECT brain blood flow images of children using statistical parametric mapping (SPM99). We studied 64 ADHD children (4-15 y, $8.03{\pm}2.57$ y. male/female:52/12) and compared them with a control group of 12 children (6-l7 y, $9.42{\pm}3.37$ y, male/female:8/4). We injected blood flow tracer $^{99m}Tc$-ethylcysteinate dimer (ECD) as a rCBF agent and took blood flow images after 30 min. by SPECT camera. In the case of hyperperfusion of rCBF in the ADHD group, we found 3 clusters clearly separated at the cingulate gyrus, Rt.cerebral occipital lobe and Lt.cerebellar post. lobe, on probability level 0.05 (P<0.05). Thirty-six ADHD patients with average hyperfusion rates between 18.72-19.30% in each cluster had more increase in blood flow than the average perfusion rate at the Rt. cerebral occipital lobe. These levels were influenced by P-value. In the case of hypoperfusion in the ADHD children, 4 decreased clusters on Lt. and Rt. cerebral frontal lobe, Lt. cerebral claustrum and Rt. cerebral, sup. temporal gyrus at P<0.01 can be seen. The average hypoperfusion rates for the ADHD children were 18.41-18.69% in each cluster, which showed more hypopefusion than the average perfusion rate at the Lt. Cerebrum inf. Frontal gyrus. The perfusion rates and the number of patients were not affected by P-value. The result of this study shows significant hyperpefusion clusters at the probability level of P:0.05 and hypoperfusion clusters at P:0.01. The number of ADHD patients in each clusters and the perfusion rate were not affected by P-value.