• Journal of Korea Port Economic Association
• /
• v.28 no.2
• /
• pp.179-194
• /
• 2012

In this study, we compared the efficiency of container terminals using DEA. To do this, we designed an AHP/DEA hybrid model using AHP and DEA, and evaluated the efficiency by comparing the container terminal operation company in Gwangyang(KEC, KIT, GICT) and Busan(HBCT, DPCT, KBCT, UPT, Gamman, PNC, PNIT, HJNC, HPNT). The proposed model can control the number of selected promising container terminal by applying DEA-AR model. This model can also improve the credibility of analysis by using objective weights through the AHP application to efficiency evaluation data and normalizing the evaluation data to apply AHP and DEA. The model assumes inputs to be container crane, transfer crane, yard tractor, and reach stacker and output as container traffic. The result shows that DPCT was an efficient DMU.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.5D
• /
• pp.705-717
• /
• 2011

The number of horizontal tower cranes, major hoisting machineries for lifting approximately 50% of entire materials in construction projects, is rapidly increasing, but a number of accidents related to the tower cranes are being continuously occurred in construction sites as well. In particular, telescoping works in the horizontal tower cranes have showed the greatest safety concerns such as falls and collapses. It is due to the fact that tasks inserting a new mast in the space made after raising telescoping cage by fluid pressure and ascending it to the required height in the telescoping works include a series of dangerous factors in safety aspects, and might cause very serious and unexpected accidents in construction sites. The primary objective of this research is to propose two conceptual models for automating the telescoping work in horizontal tower crane and conduct their technical feasibility analyses. In this study, a design concept, a position control system using hydraulic cylinders is suggested as a better alternative for automating the telescoping work. Its potential safety improvement rate compared to the conventional method is also analyzed and presented in this study.

• Journal of the Korean Society of Safety
• /
• v.31 no.3
• /
• pp.116-122
• /
• 2016

With the changes of industrial structure, contents and types in hazardous and dangerous works have been changed considerably. However, the hazardous and dangerous works by defined "Regulation for the hazardous and dangerous work employment restriction" and "Special education for safety and health"have not been amended over twenty years. This study aimed to identify the recent trends of the works by analyzing the death accidents cases from 2004 to 2013 and to present the management methods about future hazardous and dangerous works. The results showed that amount of 1,972 cases among 11,513 death accidents were equivalent to the works presented by "Regulation for the hazardous and dangerous work employment restriction". The amount of death accidents in 'Work of using construction equipment following construction machinery management act' was biggest among the death accidents cases and that of 'Work of handling pressure vessels following high-pressure gas safety control act' didn't show up. For the works in "Special education for safety and health"amount of 1,650 death accidents cases were equivalent. The amount of death accidents in 'Work involving a crane with a capacity of 1 ton or more or work which is carried out with a crane or hoist with a capacity of less than 1 ton in a workplace having at least 5 such machines' presented by "Special education for safety and health"was biggest. Also, death accidents case didn't occurred in three works presented by "Special education for safety and health". It was analyzed that works with low death accidents cases should be needed to study thoroughly the whole disaster research involving nonfatal accidents. Through this study, it was expected that regulation can be operated practically in the industrial field. Also, it is considered to increase

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.65 no.2
• /
• pp.88-93
• /
• 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.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.17 no.2
• /
• pp.83-89
• /
• 2008

This paper presents the dynamic analysis and input shaping control of a positioning stage. Vibration characteristics of the positioning stage are affected not only by the structural dynamics but also by the servo actuators that consist of the mechanism; driving motor and controller. This paper proposes an integrated dynamic model to accommodate both the structural dynamics and the servo actuators. Theoretical modal analysis with a commercial finite element code is carried out to investigate the dynamic characteristics of the experimental positioning stage. Experiments are performed to validate the theoretical modal analysis and estimate the equivalent stiffness due to the servo actuators. This paper deals with an input shaping scheme to suppress vibration of the positioning stage. Input shapers are systematically implemented for the positioning stage in consideration of its dynamics. The effects of servo control gain are also investigated. The experiments show that input shaping effectively removes residual vibrations and then improves the performance of positioning stage.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1126-1130
• /
• 2004

This paper describes the design, development, and performance testing of an autonomous ground vehicle that was developed to participate in the DARPA Grand Challenge that was held in March 2004. The authors of this paper are members of Team CIMAR which was one of twenty five teams selected by DARPA to participate in a competition to develop an autonomous vehicle that can navigate from near Los Angeles to near Las Vegas at speeds averaging twenty miles per hour. Most of the event was held on open terrain and trails in a rocky desert environment. This paper describes the overall system design and the performance of the system at the event.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.1914-1915
• /
• 2011

본 논문은 천정형 크레인의 파라미터 추정과 Fuzzy LMI 제어기법을 이용한 흔들림 억제 제어를 제안한다. 실제 크레인을 제어함에 있어서 크레인의 동적모델링 이외에도 미지의 물리적 매개변수 값을 규정하는 것은 중요한 요소이다. 이러한 점을 고려하여 크레인의 물리적 매개변수를 최소자승추정 방법을 통해 추정하여 크레인 제어의 성능향상을 제공한다. 또한 Fuzzy LMI 제어기법을 적용하여 천정형 크레인의 이동 중 발생하는 흔들림을 제어한다.

• Proceedings of the KIEE Conference
• /
• 1999.11c
• /
• pp.609-611
• /
• 1999

산업현장의 제어기들은 센서들로부터 수집된 다양한 형태의 신호들을 처리한다. 이 신호들은 고정된 값을 가지지 않고 물리적으로 변화하는 특성을 가진다. 이와 같이 변화하는 값을 처리하는 방법으로 다양한 형태의 연구가 진행되고 있고, 그 한 분야로 퍼지(Fuzzy)이론을 바탕으로 한 퍼지 제어 시스템에 대한 연구가 활발하게 진행되고 있다. Fuzzy PLC 시스템은 현재 초기단계 형태로 개발되어 사용되고 있으며 그 응용 방법도 조금씩 보급되고 있는 실정이다. 본 논문은 변화하는 값들에 대해 간결하고 적절한 제어를 수행 할 수 있는 기 개발된 Fuzzy PLC 시스템을 이용한 플랜트 제어에 대한 연구이다. 크레인(Crane) 제어용으로 사용한 Fuzzy PLC 시스템은 Moeller사의 FT4-400-MM2 PLC 모듈이다. 본 시스템을 이용하여 대상 플랜트인 크레인을 제어하는 퍼지 함수 로직을 개발하고, 입 출력 제어 프로그램 기법에 대하여 연구한다. 또한 퍼지 제어 시스템을 이용한 퍼지 제어 기법을 개발하는 과정에 대하여 소개한다. 결론적으로 Fuzzy PLC System 개발 및 응용 모델로서 제안하고자 한다.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2010.05a
• /
• pp.33-36
• /
• 2010

The attention in construction Automation is getting higher since it could be the answer to the lack of skilled labor by decrease in construction population and aging which adversely affects productivity and quality in the construction site. We are on the way to develop a construction automation system adequate for domestic circumstances in Korea; it is called RCA(Robotic-crane based Construction Automation)system. Climbing hydraulic robots system is a part of RCA system and makes Construction factory(CF) climb through the guide rail on the core wall. The safety of climbing hydraulic robots system is at issue due to the overloaded weight of CF. Preventing this issue, present study did the design verification through the structural analysis and the simulation. Mock-up test also was done to analyze the drive performance of climbing hydraulic robots system.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.100.6-100
• /
• 2002

The crane and the master-slave manipulators (MSM) are widely used as a remote handling device in nuclear facilities such as the hot cell. The equipment to be installed in the hot cell should be optimally placed within the workspace of the wall-mounted slave manipulator for the maintenance operation. Also, the slave manipulator with the end effectors should be properly positioned and oriented for the dedicated maintenance operation. Hence, the workspace and the motion of the slave manipulator, as well as, the remote operation task should be analyzed before installing the manipulators and the hot cell equipment. For this purpose, the 3D graphic simulator, which simulates the remote operation o...