• 제어로봇시스템학회논문지
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• 제22권6호
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• pp.445-452
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• 2016

This paper discusses the dynamics and control problem of an overhead shuttle system (OSS), which is a critical part of the automated container terminal at a port. The main purpose of the OSS is efficient automated transport function of containers, which also requires high precision and safety. A major difference between the OSS and the conventional container crane is the configuration of the cables for hoisting the spreader. A mathematical model of the OSS is developed here for the first time, which results in an eight-pole system. Also, open loop control methods (trapezoidal and notch-type velocity profiles) are investigated so that the command input to the overhead shuttle produces the minimum possible sway of the payload. Simulation results show that the vibration suppression capability of the OSS is superior to the conventional overhead container crane, which is partially due to the cable configuration.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.271-276
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• 2004

In this paper. dynamic behavior of the cracked beam under a moving mass is presented using the finite element method (FEM). Model accuracy is improved with the following consideration: (1) FE model with Timoshenko beam element (2) Additional flexibility matrix due to crack presence (3) Interaction forces between the moving mass and supported beam. The Timoshenko bean model with a two-node finite element is constructed based on Guyan condensation that leads to the results of classical formulations. but in a simple and systematic manner. The cracked section is represented by local flexibility matrix connecting two unchanged beam segments and the crack as modeled a massless rotational spring. The inertia force due to the moving mass is also involved with gravity force equivalent to a moving load. The numerical tests for various mass levels. crack sizes. locations and boundary conditions were performed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1100-1106
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• 2009

This study intends to develop a pulse discharge device to strengthen the pushing power by expanding the cavity of the anchor settlement to form a spheric root for the purpose of constructing the economical and stable anchor. and, a series of field test were carried out in order to check applicability of machines of pulse powered underreamed anchors. Through the experiments, the electrical characteristics of the pulse power equipment had been identified it and the dynamic pressure generated from the subsequent change had been measured. Here, the measured dynamic pressure is the cavity expansion pressure to impact on the ground around the anchor settlement. Since this pressure has effects of cavity expansion and bored surface hardening with dynamic hardening effects on the anchor settlement, it is expected that it will largely contribute the increase of pushing power with a strong frictional resistance.

• 대한기계학회논문집A
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• 제28권11호
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• pp.1672-1684
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• 2004

In this paper, an active vibration control with the use of an air-cell seat for passenger cars is investigated. The roles of the air-cell inserted between the polyurethane foam of the seat and seat cover are first to extend the seat's capability to adopt various shapes of human body and to improve the ride-comfort against road disturbances. The air-cell seat is modeled as a 1-d.o.f. spring-damper system. Because an exact modeling of the air-cell itself is alomost impossible, its dynamic characteristics are analyzed through experiments. A road-adaptive gain-scheduled sky-hook control for the air-cell seat system is proposed. The skyhook gains are scheduled in such a way that the acceleration level transmitted to human body on various road conditions is minimized. Simulations and experimental results are provided.

• 제어로봇시스템학회논문지
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• 제6권1호
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• pp.57-65
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• 2000

In this paper, a model reference adaptive control for the atomic force microscope (AFM) of tapping mode is investigated. The dynamics between the AFM system and al sample is mathematically modeled as a second order spring-mass-damper system with oscillatory inputs. The attractive and repulsive forces between the tip of the AFM system and the sample are derived using the Lennard-Jones potential energy. By non-dimensionalizing the displacement of the tip and the input frequency, the chaotic behavior near a resonance frequency is better depicted through the non-dimensionalized equations. Four nonlinear analysis techniques, a phase portrait, sensitive dependence on initial conditions, a power spectral density function, and a Pomcare map are investigated. Because the equations of motion derived in this paper involve unknown parameter values such as the damping effect of the air and the interaction constants between materials, the standard model reference adaptive control is adopted. Two control objectives, the prevention of chaos and the tracking of reference signal, are pursued. Simulation results are included.

• Child Health Nursing Research
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• 제18권3호
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• pp.119-126
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• 2012

Purpose: The purpose of this study was to examine and analyze the post operative fasting period of neonates in the intensive care unit (ICU) after receiving open heart surgery in order to provide optimal nutrition support for these neonates. The variables included biochemical nutrition indexes (albumin, total lymphocyte count, total cholesterol) and patient outcomes (duration of mechanical ventilation, ICU stay, hospital stay, infectious complication). Methods: The participants were 124 neonates in ICU after receiving open heart surgery, and the design of this study was to investigate their post operative fasting period retrospectively to analyze the biochemical nutrition indexes and patient outcomes according to post operative fasting period. Results: The results for 4 groups according to post operative fasting period showed that the group with less 48 hours of fasting had the best biochemical nutrition indexes and patient outcomes, followed by the 48-72 hour group, the 72-144 hour group, and the over 144 hour group. Conclusion: The results indicate that for new born babies receiving open heart surgery, the period of fasting after the operation should be minimized and tube feeding should be started as soon as possible.

• 한국해양공학회지
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• 제19권1호
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• pp.87-94
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• 2005

This paper investigates the constant-level luffing and time optimal control of jib cranes. The constant-level luffing, which is the sustainment of the load at a constant height during luffing, is achieved by analyzing the kinematic relationship between the angular displacement of a boom and that of the main hoist motor of a jib crane. Under the assumption that the main body of the crane does not rotate, the equations of motion of the boom are derived using Newton's Second Law. The dynamic equations for the crane system are highly nonlinear; therefore, they are linearized under the small angular motion of the load to apply linear control theory. This paper investigates the time optimal control from the perspective of no-sway at a target point. A stepped velocity pattern is used to design the moving path of the jib crane. Simulation results demonstrate the effectiveness of the time optimal control, in terms of anti-sway motion of the load, while luffing the crane.

• Journal of Chest Surgery
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• 제37권5호
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• pp.456-459
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• 2004

16개월 된 남자 유아가 목욕탕에서 쓰러진 상태로 발견되었으나 신체 모든 부위에 타박흔적은 없었다. 점진적인 호흡곤란이 지속되어 타 병원에 내원하여 흉부 X-선 촬영상 오른쪽 가슴에 심한 수흉으로 확인되어 흉강 천자와 폐쇄식 흉관 삽입술을 시행하여 배액하였으나 하루 200 ㏄ 이상의 유미액이 배액되어 2003년 7월 17일 본원으로 전원되었다. 삽관 후 21일 이상 금식 등으로 치료하였으나 증상이 호전되지 않아 우측 소개흉으로 절개하여 흉관 결찰 수술을 시행하였다. 수술 후 우측농흉이 발생하였으나 항생제 투여로 수술 후 30일째 경과 양호하여 흉관을 제거하게 되었으며 수술 3개월 후 현재 경과 양호하여 보고하는 바이다.

• 대한기관식도과학회:학술대회논문집
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• 대한기관식도과학회 1976년도 제10차 학술대회연제 순서 및 초록
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• pp.90.3-90
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• 1976

식도이물에 의한 식도천공은 날카로운 이물에 의한 예가 대부분이며 드물게 이물의 장기잔류에 의한다. 저자들은 8개월된 소아에서 한쪽 끝이 낚시모양으로 된 길이 20cm 굵기 3mm 정도의 철사를 연하하여 낚시 모양의 끝은 제1 식도협착부에서 식도를 천공하고 경부 좌측의 종창을 초래하였으며 철사의 반대쪽 끝은 입밖으로 나와 있는 흥미있는 식도이물 1례를 경 청하였다. 식도경검사하에서 이물제거를 시도하였으나 실패하여 경부절개하에 낚시모양의 끝은 잘라서 제거하고 나머지는 식도경검사하에 제거한 후 약 4주일동안 금식 및 tube feeding으로 치유되었다.

• Journal of Chest Surgery
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• 제31권3호
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• pp.329-335
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• 1998

55세 남자환자가 흉부 불편감, 연하장애와 연하통을 주소로 입원하였다. 식도내압검사상 하부식도 괄약근의 이완이 전혀 관찰되지 않았다. 식도 조영술상 "double-barrelled 식도" 또는 점막 선조(mucosal stripe) 소견을 보였다. 내시경 검사상 상부 식도에 기관-식도누공의 형태를 보는 듯한 개구부가 있었다. 또한, 하부 식도에는 두군데의 점막 열창이 보였다. 이후 환자는 금식과 비경구적인 영양공급을 하면서 수주간 치료하였나, 증상의 호전을 볼수 없었다. 그래서 전신 마취하에 상부식도에 있던 가성내강의 개구부를 일차봉합하였다. 수술후 환자는 경한 연하곤란을 제외하고는 증상이 좋아졌다. 환자는 조심스런 경구섭취를 하고 퇴원하였다. 환자는 외래에서 추적검사상 발열이나 연하장애가 없었으며, 식도 조영술상 호전되는 양상을 보였다. 저자들은 보존적 치료와 수술적 치료를 시행했던 자발성 점막하 식도 박리의 특이한 경우를 치험하였다. 이에 관련된 문헌과 함께 보고하는 바이다. 보고하는 바이다.