• Fire Science and Engineering
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• v.34 no.3
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• pp.35-42
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• 2020

The accurate prediction of fire detector activation time is required to ensure the reliability of fire modeling during the safety assessment of performance-based fire safety design. The main objective of this study is to determine the activation temperature and the response time index (RTI) of a fixed heat detector, which are the main input factors of a fixed-temperature heat detector applied to the fire dynamics simulator (FDS), a typical fire model. Therefore, a fire detector evaluator, which is a fire detector experimental apparatus, was applied, and 10 types of domestic fixed-temperature heat detectors were selected through a product recognition survey. It was found that there were significant differences in the activation temperature and RTI among the detectors. Additionally, the detector activation time of the FDS with the measured DB can be predicted more accurately. Finally, the DB of the activation temperature and RTI of the fixed-temperature heat detectors with reliability was provided.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.7
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• pp.701-708
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• 2009

The flight control law of developed flight control computer(DFLCC) is developed based on operation flight program of advanced trainer aircraft full scale development final configuration. The flight control law design is used common use development tool in GUI(Graphic User Interface) environment. The flight control law transformed to C-Code is reflected in OFP. The OFP is verified by the standardized verification process. But, before standardized verification process, we need preliminary verification process such as similarity of flight control law and reliability of developed HILS. Similarity of flight control law is verified by comparing the aircraft response of advanced trainer aircraft and those of the developed control law. Also, reliability of developed HILS is verified by comparing the aircraft response of HILS and Non-real time simulation result. This paper verifies similarity of developed control law and reliability of HILS environment as comparing aircraft response.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.8
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• pp.665-670
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• 2014

In this paper, characteristics of a tidal current power generation system are analysis using power hardware-in-the-loop simulation (PHILS). A 10 kW motor generator set is connected to the real grid through a fabricated 10 kW back to back converter. A power control scheme is applied to the back to back converter. A 2 MW class tidal current turbine is modeled in real time digital simulator (RTDS). Generating voltage and current from the 10 kW PMSG is applied to a 2 MW class tidal current turbine in the RTDS using PHILS. The PHILS results depict the rotation speed, power coefficient, pitch angle, tip-speed ratio, and output power of tidal current turbine. The PHILS results in this paper can contribute to the increasing reliability and stability of the tidal current turbines connected to the grid using PHILS.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2165-2172
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• 2010

This paper presents the operation algorithm of microgrid on the Real Time Pricing(RTP) for building the smart grid. RTP is higher power price variability than flat rate and time of use. However it has an effect on peak clipping and peak load shifting due to the increased price on peak time power demand. When the RTP are applied to the microgrid system, the proposed algorithm is able to be effective and economic operation. The implemented system is operated for the economic operation in microgrid connected with the power system. On the other hand, when the microgrid is operated on isolation mode, it focus on the improvement of stability and the power supply reliability of the sensitive loads. The test system are implemented and calculated on various operation modes based on non-dispachable generator output and RTP data for validating the proposed operation algorithm. The calculated results are compared to the implemented results using real-time simulator. It can be confirmed that the proposed operation system are identical results to the calculated one. When the proposed operation algorithm is applied to the system, it can be show the effectiveness of the peak clipping and peak load shifting and the improvement of economic feasibility.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1255-1260
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• 2011

In this paper, we study on the reliability of Very High-rate Power Line Communication (VH-PLC) for Smart Grid, so that the resultant data rate is over 400Mbps at a physical layer. Firstly, reviewing the research trend of the PLC, we discuss the required techniques for supporting the Smart Grid. Considering a pre-specification with the value of several parameters, we investigate a multi-carrier modulation technique to overcome limitations of higher rate transmission under power line channel environments. Then, we propose a system specification of the VH-PLC in the sense of enhancing two features. One is resolving the problem of the co-existence of the deployed high-speed PLC according to the published standardization of KS X 4600-1 in Korea. The other is getting better performance on the grid adopting the diverse element techniques, such as multi-carrier modulation, a subcarrier utilization mode, a variable rate LDPC (Low Density Parity Check) code, and a time and frequency diversity technique. Further, a simulation tool, composed of an Event-Driven simulator and a Time-Driven simulator, is developed for the purpose of verifying the system performance and continuously cross-checking the test bench signal of the proposed VH-PLC system.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.2
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• pp.28-35
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• 2015

Thin film electronic devices which brought the current mobile environment could be fabricated only under the high quality vacuum conditions provided by high vacuum systems. Especially for the development of advanced thin film devices, constant high quality vacuum as the deposition pressure is definitely needed. For this purpose, the variable conductance throttle valves were employed to the high vacuum system. In this study, the effects of throttle valve applications on vacuum characteristics were simulated to obtain the optimum design modelling of variable conductance of high vacuum system. Commercial simulator of vacuum system, $VacSim^{(multi)}$, was used on this investigation. Reliability of employed simulator was verified by the simulation of the commercially available models of high vacuum system. Simulated vacuum characteristics of the proposed modelling were agreed with the observed experimental behaviour of real systems. Pressure limit valve and normally on-off control valve were schematized as the modelling of throttle valve for the constant process-pressure of below $10^{-3}torr$. Simulation results were plotted as pump down curve of chamber, variable valve conductance and conductance logic of throttle valve. Simulated behaviors showed the applications of throttle valve sustained the process-pressure constantly, stably, and reliably.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1651-1654
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• 2003

The process equipment for handling high level radioactive materials, such as spent nuclear fuel, is operated within a sealed facility, called a hot cell, due to high radioactivity. Thus, this equipment should be maintained and repaired by remotely operated manipulator. In this study, to carry out the sale and effective maintenance of the process equipment installed in the hot cell by a servo type manipulator, a collision free motion planning method of the manipulator using virtual prototyping technology is suggested. To do this, the parts are modelled in 3-D graphics, assembled, and kinematics are assigned and the virtual workcell is implemented in the graphical environment which is the same as the real environment. The method proposed in this paper is to find the optimal path of the manipulator using the function of the collision detection in the graphic simulator. The proposed path planning method and this graphic simulator of manipulator can be effectively used in designing of the maintenance processes for the hot cell equipment and enhancing the reliability of the spent fuel management.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.367-374
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• 2017

The goal of this study was to develop control algorithms to improve the steering performance of a 120-ton all-terrain crane. To accomplish this, a hydraulic steering system for the crane was modeled using AMESim software, and a PID steering control algorithm was designed in the MATLAB/Simulink environment. The performance of the designed controller was verified through multiphysics co-simulations based on a real-time simulator.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.3
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• pp.1-7
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• 2011

As the technologies of electronic device have advanced these days, most of mechanical systems are designed with electronic control unit to take advantage of control parameter adaption to operating conditions and firmware flexibilities as well. On-board diagnosis, which detects the system malfunction and identifies potential source of error with its own diagnostic criteria, and fail-safe that can switch the mode of operation in view of recognized error characteristics enables easy maintenance and troubleshooting as well as system protection. This paper dealt with the development of diagnosis and fail-safe function for proportional flow control valve. All type of errors related to valve control system components are investigated and assigned to a specific hexadecimal codes. Cumulative error detection algorithm is applied in order for the sensitivity and reliability to be appropriate. Embedded simulator which runs simultaneously with system program provides the virtual error simulation environment for expeditious development of error detection algorithm. The diagnosis function was verified both with solenoid valve and embedded simulator test and it will enhance the valve control system monitoring function.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.1
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• pp.34-39
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• 2006

In high-voltage devices such as thyristor, beveling is mostly used junction termination method to reduce the surface electric field far below the bulk electric field and to expand the depletion region thus that breakdown occurs in the bulk of the device rather than at the surface. However, coating material used to protect the surface of the device contain so many charges which affect the electrical characteristics of the device. And device reliability is also affected by this charge. Therefore, it is needed to analyze the effect of surface charge on electrical characteristics of the device. In this paper, we analyzed the breakdown voltage and leakage current characteristics of the thyristor as a function of the amount of surface charge density. Two dimensional process simulator ATHENA and two-dimensional device simulator ATLAS is used to analyze the surface charge effects.