• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1634-1644
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• 2016

In this paper, a current-fed two-inductor bi-directional DC/DC converter using resonance (CF-TIBCR) and its design method are proposed. The CF-TIBCR has characteristics of low current ripple and a high current rating because of two separated inductors. Also, it achieves zero voltage switching for all switches and zero current switching for switches of a low voltage stage by using the resonant tank. Besides, a voltage spike problem in conventional current-fed converters is solved without the need for an additional snubber or clamping circuits. As a result, the CF-TIBCR features high step-up and high efficiency. Since the proposed converter has difficulty achieving the soft-switching condition when the converter requires the low voltage transfer ratio, a method that varies the number of resonant cycles is adopted to extend the output voltage range with satisfying the soft-switching condition. The principles of the operation characteristics are presented with a theoretical analysis, and the proposed converter is verified through results of an experiment using a laboratory prototype.

• 한국멀티미디어학회논문지
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• 제23권8호
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• pp.1019-1029
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• 2020

In this paper, we propose a novel knowledge distillation algorithm to create an compressed deep ensemble network coupled with the combined use of local and global features of face images. In order to transfer the capability of high-level recognition performances of the ensemble deep networks to a single deep network, the probability for class prediction, which is the softmax output of the ensemble network, is used as soft target for training a single deep network. By applying the knowledge distillation algorithm, the local feature informations obtained by training the deep ensemble network using facial subregions of the face image as input are transmitted to a single deep network to create a so-called compressed ensemble DCNN. The experimental results demonstrate that our proposed compressed ensemble deep network can maintain the recognition performance of the complex ensemble deep networks and is superior to the recognition performance of a single deep network. In addition, our proposed method can significantly reduce the storage(memory) space and execution time, compared to the conventional ensemble deep networks developed for face recognition.

• 전기학회논문지
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• 제64권6호
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• pp.885-890
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• 2015

LLC resonant converter has been widely used because of its high efficiency and high energy density. In this paper, we designed a LLC resonant converter as the main power supply of the Nd:YAG pulse laser. First harmonic approximation (FHA) is used to model the LLC resonant converter. FHA equivalent circuit model and the transfer function of the LLC resonant converter is proposed. Soft start technology is also used to suppress the surge current. The laser output simulation test result is identical with the practical test, the laser energy of every pulse can reach up to 2.5J, and the pulse per second (PPS) can be adjusted from 6 to 18. The power system is verified stable and reliable by both of the simulation and experiment results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1373-1377
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• 2003

Current prostheses for amputees are generally extrinsic wearing socket type that the coupling between body stump and appliance wraps the soft tissue and this structure causes several problems :applying direct weight to soft tissue such as skin and muscle, skin trouble of contacting area and pain. In this study, osseointegration implant is a method to directly connect prosthesis to the residual stump skeletal tissue of arm, finger and leg through surgical operation. Technology presented in this paper essentially solves the problems of pain and abnormal weight transfer system indicated above and recovers the functions of the amputated arm and leg. In this paper, implant shape was designed for the first step for the development of osseointegration implant and then we studied the possibility to apply this osseointegration implant to human body by performing implant insertion operation to beagle tibia for the clinical animal test and normal beagle's gait analysis was executed in order to quantitatively verify the beagle's skeletal functions after the implant insertion.

• Journal of Trauma and Injury
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• 제22권1호
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• pp.103-107
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• 2009

Purpose: There are no reports on amusement-park-related injuries in Korea. Thus, the objective of this study was to describe traumatic injury patterns that occurring in an amusement park. Methods: The medical records of an infirmary were retrospectively reviewed. From January 1, 2008, to December 31 2008, patients who were transferred to the nearest emergency departments of hospitals for the purpose of further test and treatment were enrolled. Demographics, injury types and involved parts of the body were analyzed. Results: A total of 3,608 patients visited an infirmary for traumatic injury and about two-thirds had soft issue injuries. Of those, 191 patients (5.3%) were transferred to the emergency department of a hospital. Of the patients who were transferred to a hospital, laceration and contusion were the responsible injuries for about half. Laceration was the most common injury in pediatric patients, and a sprain or a strain was the most common in adult patients. The most commonly injured parts of the body were the extremities in adult patients. However, in pediatric patients, injuries of the head, face and neck were similar to injuries of the extremities. Conclusion: Soft tissue injury was the most common amusement-park-related injury. Laceration was the most common reason to transfer a patient to a hospital. There were differences in injury type and injured part of the body between adult and pediatric patients.

• 한국진공학회지
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• 제12권3호
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• pp.193-199
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• 2003

아크-마그네트론 복합 공정법에 의해 Cu, Ag 도핑된 TiN 나노 복합 화합물 박막을 합성하고 각 금속원소 종류 및 함량에 따른 기계적 특성 및 나노 구조로의 상변화 거동을 관찰하였다. 합성된 박막은 약 40 ㎬의 높은 경도치를 나타내었으며 2 at% 미만의 낮은 금속 원소 함량에서 최대 경도간을 나타내었다. 금속 원소 함량이 증가할수록 결정립 미세화 및 다결정화가 진행되어 초고경도 특성을 나타내는 나노구조 박막이 합성되었으며 도핑되는 금속원소 종류에 따라 나노 구조로의 상변화 기구가 상이함을 관찰하였다. TiN 박막내 도핑된 Cu는 Ti와 일부 결합을 이루면서 Ti의 자리를 치환하는 것으로 나타났으나, Ag는 Ti와 결합을 이루거나 Ti 격자 자리를 치환하는 것이 아니라 독립적으로 결정립계에 존재하여 charge transfer만을 발생시키는 것으로 관찰되었다.

• 한국지반공학회논문집
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• 제19권3호
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• pp.45-51
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• 2003

복합기초의 한 형식인 소일시멘트 말뚝의 거동 특성을 컴퓨터 해석을 통하여 연구하였다. 연직하중을 받는 소일시멘트말뚝의 거동 특성을 ABAQUS라는 상용 프로그램을 사용하여 조사하였으며 해석조건은 지반물성치, 말뚝의 길이, 치환율, 강성비, 하중 조건 등을 달리하여 실시하였다. 해석 결과는 하중의 전이 및 침하특성 뿐만 아니라 효과적인 말뚝길이와 말뚝 및 지반의 하중 분배에 관하여서도 유용하게 쓰일 수 있음이 판명되었다. 또한 복합기초를 설계할 때 강성비, 치환율이 설계에 가장 큰 영향을 미치는 인자로 나타났다.

• Archives of Reconstructive Microsurgery
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• 제14권2호
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• pp.144-151
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• 2005

Purpose: Disaster as traffic accident, industrial disaster, high voltage electrical bum and flame burn of extremity have a destructive effect because of the involvement of deep structure. Generally, such injury may result in decreased function or loss of limb. In this study the successful use of the combined scapular/parascapular flap as microsurgical transfer to cover extensive defect of electrical and flame bum is reported. Material and Method: Between January 2000 and June 2001, the combined scapular and parascapular flap was used for the coverage of soft tissue defect for 7 patients were admitted to our department with high voltage electrical bum and flame burn. The recipient site were the wrist joint in 2 cases, the forearm in 1 case, the ankle joint in 1 case, the foot dorsum in 1 case, the heel in 1 case. Result: Flap survival was complete in all patients. The result of flap coverage for these deep wound was successful. Conclusion: The advantages of scapular/parascapular combined flap were coverage of the large defect, easy shaping of the flap to fit the required three dimensional configuration around the joint, non hair bearing skin of uniform thickness, minimal donor site morbidity.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.905-917
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• 2008

Road or Railway construction over soft ground is needed to be considered on secondary consolidation which will be caused differential settlement, lack of transport serviceability, higher maintenance cost. Especially for the railway construction in the second phase of Gyung-Bu or Ho-Nam high speed railway, concrete slab track has been adapted as a safe and cost effective geotechnical solution. In this case controlling the total settlement under the tolerance is essential. And pile supported geogrid reinforced construction method is suggested as a solution for the problem of the traditional method on soft soil treatments. Pile supported geogrid reinforced construction method consists of piles that are designed to transfer the load of the embankment through the compressible soil layer to a firm foundation. The load from the embankment must be effectively transferred to the piles to prevent punching of the piles through the embankment fill creating differential settlement at the surface of the embankment. The arrangement of the piles can create soil arching to carry the load of embankment to the piles. In order to minimize the number of piles geogrid reinforced pile supported construction method is being used on a regular basis. This method consists of one or more layers of geogrid reinforcement placed between the top of the piles and the bottom of the embankment. This paper presents several methods of pile supported geogrid reinforced construction and calculation results from the several methods and comparison of them.

• 한국지반환경공학회 논문집
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• 제15권1호
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• pp.5-12
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• 2014

본 논문은 심층연약지반 개량용 전기가열장치를 개발하여 경기도 화성시 인근 연약지반에 적용한 것이다. m당 1 kW의 전기를 소비하는 니켈-크롬선으로 구성된 길이 4.0 m의 전기가열장치를 지표하 3.5~6.5 m 사이에 설치하여 48시간의 지반가열을 2회, 총 96시간 실시하였으며, 온도계와 압력계를 지표하 5.0 m 지점에 매설하여 지반가열에 의한 온도 및 증기압 변화를 측정하였다. 실험결과 가열원으로부터 횡방향 거리의 온도분포 및 선단지지력의 변화는 이차함수를 나타내었으며, 둘 다 R2값은 1로 산정되었다. 또한, 전기가열로 인해 수증기가 배출됨에 따라, 함수비 및 간극수압이 감소함을 관찰할 수 있었다.