• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2006년도 추계학술대회
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• pp.525-528
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• 2006

This paper considers the vehicle dispatching problem in the automated material handling system (AMHS) of a large scale semiconductor fabrication line, which consists of 18 bays, 468 equipments and uses more than 130 overhead hoist transporters (OHT). We propose an assignment problem based vehicle dispatching approach to take advantage of simultaneous vehicle reassignment based on up-to-date system status. The proposed approach compares fsvorably with the shortest travel distance first rule and with the reassignment based rule which was recently proposed by the authors, in the number of vehicles required and the average lead time.

• Journal of Power Electronics
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• 제16권4호
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• pp.1598-1611
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• 2016

In some special occasions with strict size requirements, such as mine hoists, improving the design accuracy of the forced-air cooling systems of NPC three-level inverters is a key technology for improving the power density and decreasing the volume. First, a fast power-loss calculation method was brought. Its calculation principle introduced in detail, and the computation formulas were deduced. Secondly, the average and dynamic power losses of a 1MW mine hoist acting as the research target were analyzed, and a forced-air cooling system model based on a series of theoretical analyses was designed with the average power loss as a heat source. The simulation analyses proves the accuracy and effectiveness of this cooling system during the unit lifting period. Finally, according to an analysis of the periodic working condition, the maximum power-loss range of a NPC three-level inverter under multi cycle operation was obtained and its dynamic power loss was taken into the optimized cooling system model as a heat source to solve the power device damage caused by instantaneous heat accumulation. The effectiveness and feasibility of the optimization design based on the dynamic power loss calculation of the maximum power-loss range was proved by simulation and experimental results.

• 한국정밀공학회지
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• 제22권1호
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• pp.53-60
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• 2005

The wire rope of container crane is a important component to container transfer system and is used in a myriad of various applications such as elevator, mine hoist, construction machinery, and so on. If it happen wire rope failures in operating, it may lead to the safety accident and economic loss, which is productivity decline, competitive decline of container terminal, etc. To solve this problem, we developed the active and portable wire rope fault detecting system. The developed system consists of three parts that are the fault detecting, signal processing, and remote monitoring part. All detected signal has external noise or disturbance according to circumstances. Therefore we applied to discrete wavelet transform to extract a signal from noisy data that was used filter. As experimental result, we can reduce the expense for container terminal because of extension of exchange period of wire rope for container crane and this system is possible to apply in several fields to use wire rope.

• 제어로봇시스템학회논문지
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• 제3권2호
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• pp.132-138
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• 1997

Six different types of velocity profiles of trolley movement of a container crane are investigated for the minimal sway angle at the target trolley position. Three velocity patterns which include trapezoidal, stepped and notched-type velocity patterns are obtained assuming constant rope length. The notched type velocity pattern is shown to be derived from the time-optimal bang-bang control. The stepped type velocity pattern can be shown to be derived as bang-off bang control as well. Considering the damping effect due to hoist motion a double stage acceleration pattern is also analyzed. The main objective of the paper is to show how much time-reduction can be obtained among several velocity patterns appearing in the literature.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.44-45
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• 2019

Tower cranes are essential equipments that play a key role in the overall process of large-scale construction projects, as well as high-rise apartments construction projects. Tower cranes hoist various loads near and over people, working in crowded environments, sometimes in overlapping work areas, and often under the constraints of time, budget, and labor. This work system further increases the safety risks of sites with inherently hazardous workplaces. The methodology of this research was based on a comprehensive inquiry of a team of experts, including safety managers and equipment managers of major construction companies and previous literature search. Due to the limited resources available to improve safety and prevent accidents, more attention should be paid to all parties involved in factors that have been evaluated to have a significant impact on site safety due to tower crane operations.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2020년도 춘계학술발표대회
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• pp.368-371
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• 2020

반도체 제조시설의 효율성을 위해 대부분의 현장에서는 물류 자동화 시스템 (AMHS, Automated Material Handling System)을 도입하여 운영하고 있다. OHT(Overhead Hoist Transfer)는 반도체 공정에서 주로 활용되는 Monorail 컨베이어 형태의 자동 반송 시스템의 일종으로 작업물을 들고 제조라인 위에 설치된 레일을 따라 자율적으로 이동하는 방식으로 운영된다. 도체 물류 시스템의 계층적인 구조적 특징과 고가의 재료를 다루고, 외부유출이 어려운 실제 공정 현장, 실험 환경의 시간, 공간적 구축 등의 현실적 특징 때문에 반도체 제조 공정의 자동화 물류시스템에 대한 모델링 및 시뮬레이션을 통한 연구의 필요성이 대두되고 있다. 본 논문에서는 OHT를 효율적으로 제어하기 위해 DEVS(Discrete Event System Specifications) 형식론을 기반으로 OHT 시스템 모델링 및 시뮬레이션 설계 방법을 제안한다. 이를 위해 반도체 제조 시스템의 전반적인 물류 과정에 대해 분석하고, DEVS 형식론에 대해 연구하며, 이를 바탕으로 반도체 물류 시스템을 위한 모델링 및 시뮬레이션을 설계하였으면, 실험을 통해 제안된 모델리 반도체 물류 시스템 시뮬레이션을 수행할 수 있음을 보인다.

• 전기학회논문지P
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• 제65권2호
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• pp.88-93
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• 2016

Soft starters are used with large induction motors in blowers, fans, pumps and the crane hoist drives. AC voltage controllers are used as soft starters in induction motors for starting and to adjust its speed. Soft-starter starting system uses phase control method of input electric source through the setting of the thyristor(SCR) firing angle ${\alpha}$, and it can control input electric source stably and continuously from beginning of starting to ending of starting. In this paper, it is verified that power stack of high-voltage with SCR series system possesses dielectric strength and input electric source is controlled stably by phase control. Especially, from the driving experimental of proposed soft-starter operating, a smoothing acceleration and inrush current decrease can be achieved by the series SCR trigger.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2002년도 추계공동학술대회논문집
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• pp.155-159
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• 2002

Wire ropes are used in a myriad of various industrial applications such as elevator, mine hoist, construction machinery, lift, and suspension bridge. Especially, wire rope of crane is important component to container transfer. If it happens wire rope failures in operating, it may lead to safety accident, economic power loss by productivity decline, competitive power decline of container terminal and so on. To solve this problem, we developed wire rope fault detecting system as a portable instrument, and this system is consisted of 3 parts that fault detecting part using hall sensor, permanent magnets and analog unit, and digital signal processing part using data acquisition card, monitoring part using wavelet transform, denoising method. In this paper, a wire rope is scanned by this system after makes several broken parts on the surface of wire rope artificially. All detected signal has external noise or disturbance according to circumstances. So, we applied to discrete wavelet transform to extract a signal from noisy data that was used filter. In practical applications of denoising, it is shown that wavelet pursue it with little information loss and smooth signal display. It is verified that the detecting system by denoising has good efficiency for inspecting faults of wire ropes in service. As a result, by developing this system, container terminal could reduce expense because of extension of wire ropes exchange period and could competitive power. Also, this system is possible to apply in several fields like that elevator, lift and so on.

• 한국시뮬레이션학회논문지
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• 제28권4호
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• pp.11-20
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• 2019

본 논문에서는 반도체 FAB에서의 OHT의 제어기를 검증하는 HIL(Hardware-In-the-Loop) 시뮬레이션 방법론을 제안한다. 반도체 FAB의 OHT 네트워크에는 수많은 OHT들이 동시에 운영될 수 있으므로 OHT 제어기에 대한 완벽한 검증은 물류 설비 안정성을 보장하는 데 매우 중요하다. 제어기는 정상적인 상황에 대해서 뿐 아니라 예측하기 힘든 비정상적인 상황에 대해서도 고려하여 설계되어야 한다. 따라서 본 연구에서는 제어기의 검증을 위해 비정상 상황을 생성할 수 있는 레일 네트워크와 OHT를 포함한 가상 환경을 사용하는 HIL 시뮬레이션 방법론을 제안한다. 제안되는 HIL 시뮬레이션 방법은 구현되었고, 다양한 예제를 통해 테스트 되었다.

• 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.