• Proceedings of the KSR Conference
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• 2009.05a
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• pp.855-859
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• 2009

In this paper, we introduce the estimation method by Risk or SIL(Safety Integrity Level) for the criterion of safety assurance and summarize each application method and target. IEC 62278(EN 50126) which is international standard for the specification and verification of the railway system RAMS indicate a criterion of safety assurance. Especially, it recommend the safety verification by continuous verification as the order of requirement establishment, design, manufacture, installation, operation, and maintenance for the equipment not easy to quantify the operation environment. In this paper, we study the SIL requirement allocation method relating to internal new system development and existing system improvement by analysing SIL recommendations which were used to understand SIL for a train control equipment in 1990s in IRSE and theoretically their allocation background. This paper help the safety management of Korea train control system to develope the quantitative management procedure as international level by analyzing the SIL requirement allocation by operation agency and the right SIL verification procedure by manufacture and indicating the example to assure safety because it is necessary for improvement and localization for the Korea train control system having highly dependence on aboard technology.

• Journal of Information Technology Applications and Management
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• v.30 no.6
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• pp.81-90
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• 2023

In aviation, with the rapid transformation of the mobility industry, UAMs are emerging to operate green low-altitude airspace in urban environments. In order for UAM aircraft to fly safely transporting passengers and cargo in low-altitude urban airspace, a traffic control system that supports the safe operation of the aircraft is essential. In particular, traffic control systems that reflect the characteristics of the flight environment, such as operating at low altitude in urban environments for a short period of time, are required. In this study, we define the definition of UATM and its main services that perform traffic control for the safe operation of UAMs. In addition, we analyzed the development trends of UATM systems based on domestic and overseas cases. Based on these analyses, we present the results of the concept design of the UATM system. After analyzing UATM development cases, we found that there is no commercialized UATM system, but overseas development is focused on systems that can integrate ATM and UTM. And we identified key stakeholders and interface data, and performed UATM system architecture and functional design based on the identified data. Finally, as a necessary element for the future development of UATM systems, we propose the establishment and advancement of UAM traffic flow management systems, the establishment of integrated control systems, and the development of interface with aircraft operation systems in preparation for the unmanned UAM aircraft.

• Nuclear Engineering and Technology
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• v.44 no.4
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• pp.369-378
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• 2012

A load-following operation in APR+ nuclear plants is necessary to reduce the need to adjust the boric acid concentration and to efficiently control the control rods for flexible operation. In particular, a disproportion in the axial flux distribution, which is normally caused by a load-following operation in a reactor core, causes xenon oscillation because the absorption cross-section of xenon is extremely large and its effects in a reactor are delayed by the iodine precursor. A model predictive control (MPC) method was used to design an automatic load-following controller for the integrated thermal power level and axial shape index (ASI) control for APR+ nuclear plants. Some tracking controllers employ the current tracking command only. On the other hand, the MPC can achieve better tracking performance because it considers future commands in addition to the current tracking command. The basic concept of the MPC is to solve an optimization problem for generating finite future control inputs at the current time and to implement as the current control input only the first control input among the solutions of the finite time steps. At the next time step, the procedure to solve the optimization problem is then repeated. The support vector regression (SVR) model that is used widely for function approximation problems is used to predict the future outputs based on previous inputs and outputs. In addition, a genetic algorithm is employed to minimize the objective function of a MPC control algorithm with multiple constraints. The power level and ASI are controlled by regulating the control banks and part-strength control banks together with an automatic adjustment of the boric acid concentration. The 3-dimensional MASTER code, which models APR+ nuclear plants, is interfaced to the proposed controller to confirm the performance of the controlling reactor power level and ASI. Numerical simulations showed that the proposed controller exhibits very fast tracking responses.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1480-1484
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• 2004

In this paper, a self-propulsive and small concrete floor finishing trowel robot with twin trowels is proposed. Due to the small size and omni-directional moving capability, it is adequate for small space such as apartment. By adjusting the posture of trowels, it can move in any direction without wheels. We used cheap PIC processor for the cost saving design of the modules and adopted mode processors for easy operation of control stick. For the position control of the robot, we made a motion control algorithm appealing to the stepping motor driver module and the wireless communication module between the robot and PC (or control stick). In this paper, we discuss the control problem of the floor finishing robot in order to move to the right position. By comparing experimental result with simulation, we show the validity of the robot mechanism, sensors, and the control system.

• Journal of the Semiconductor & Display Technology
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• v.5 no.4 s.17
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• pp.11-15
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• 2006

Expose equipment system that is used for manufacturing process of Flat Panel Display, is most important equipment in whole process. Expose equipment that is for making pattern of mask on substrate, consists of optical part, stage part and transport part. The stage is an important part that aligns mask and substrate for delivering pattern of mask to substrate exactly. In this paper, control system of expose stage that is able to use mask and substrate of diverse size, with PC controller using GUI interface instead of PLC control system. The existing PLC control system does not have the suitable structure for using mask of diverse size. GUI interface integration control system is based on PC. So it has the advantage of convenient use and active operation. We embodied PLC control system in integration control system based on PC, and verified utility possibility through the standard test course.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.1
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• pp.96-104
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• 2007

Glass melting process is influenced by both control and observation factors, where control factors include quantity and mixing ratio of raw material, the amount of fuel and air in-take. Further observation factors include temperature and pressure at each step of process inside glass melting furnace. Ambient Control is an effective means to eliminate complications from excessive variation among raw materials, or external disturbance from wide fluctuation of environment around equipments. Ambient Control uses both control and observation factors mentioned above. This study suggests an effective Proactive Control System that can enable genuine 4M standardization in glass melting furnace by applying Ambient Control.

• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.272-280
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• 2022

An aircraft carrier is a combat ship that acts as an aircraft base at sea and performs combat through aircraft mounted as a military ship operating the aircraft. The Navy proposed a 40,000-ton light aircraft carrier operation plan that could be equipped with vertical takeoff and landing fighter jets and helicopters around 2033, and based on this, this study examined the operation of aircraft control equipment among the aviation support systems required for operating light aircraft carriers in Korea. PriFly, TWR's ILARTS, ILM for airspace control, ASR, PAR, LAAS or RNAV, PALS (JPALS) for access control are required as essential equipment, and communication network and SCATT-16 are required along with URN-25 TACAN, ICLS (El/Az), ACLS OLS, MOVAS, IFLOLS, etc. This study consists of two parts, and part 2 will describe a specific control method on an aircraft carrier.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.7
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• pp.1061-1067
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• 2008

Direct Torque Control[DTC] and Vector Control are the two schemes developed for high performance induction motor drives. DTC based induction motors are being increasingly used in various industrial applications. DTC offers fast torque response and better speed control with lesser hardware and processing costs as compared to vector controlled drives. However, conventional DTC suffers from high torque ripple, current harmonics and low performance during torque transients. In this paper a new Direct Torque Control[DTC] method of induction motor is presented. In comparison with the conventional DTC method, the PWM technique is applied to proposed control method. In this method, decoupling mechanism is not required and the torque, the flux magnitude are under control using PI controllers and generating the voltage command for inverter control. Therefore torque and speed ripple could be reduced in comparison with the conventional switching table DTC.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.150-158
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• 1999

A driving system of a dynamic FOG compass with a stabilized platform is described. A stepping motor adopted as a driving motor is required to maintain a stable operation with constant speed and low oscillation for the proper operation of the FOG compass itself. The previous stabilization scheme operated on frequency-modulated supply is modified to include fuzzy control algorithm. The proposed scheme has advantages, particularly in the size, weight and flexibility of the driving system.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.208-216
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• 1999

Nowadays coustomer's needs for high surface quality steel sheet has greatly increased, so it is necessary to pay more attention to the roll grinding, texturing and handling. POSCO can acquire high surface quality roll and high productivity through World-first fully automated Roll Shop system which had been constructed '94.10.1∼'97.8.28 at Kwangyang Works. Roll Shop Automation System consists of Level-I, II, III control system and 23 automated machines. After the completion of the construction, the system started smoothy and keeps its operation with high productivity as expected. The installation of this system gave an epoch-making man power saving. This paper introduce its main facilities and operation.