• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.220-229
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• 1996

We presetn sytem-level simulation methodology as well as environment setup established for CDMA digtial cellular mobile station in an effort to verify CDMA modem ASIC design. To make the system-level simulation feasible, behavioral modeling of a microcontroller was first carried out with VHDL. In addition, models written in C language were also developed to provide ASIC with realistic input data. Finally, the netlist of CDMA modem ASIC was loaded on the a hardware accelerator, which was interfaced with VHDL simulator, and ismulation was performed by excuting the actual CDMA call processing software. Simulation resutls thus obtained were confirmed by comparing them with the emulation resutls from the actual system constructed on hardware modeler. these methods were proved to be effective in both discovering in advance malfunctions when embedded in the system or design errors of ASIC and reducing simulation time by a factor of as much as 20 in case of simulation at gate-level.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1594-1598
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• 2007

Energy saving is an important topic for each heavy user of the power system, including railway operators. Therefore, four strategy of train operations studied that maximum speed reduction, reduced acceleration rate, anticipatory coasting, and saw-tooth coasting for energy saving. The Simulation model of the study used to investigate the performance of a railway system, and it was used to study the effect of energy saving strategies for the train operation. The Study investigate train operation strategy for energy saving, investigate the effect of strategy, and find the energy optimization of acceleration, coasting, braking section used Run-Curve simulator from train data.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.795-798
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• 2016

Transmission X-ray tubes based on carbon nanotube have attracted significant attention recently. In most of these tubes, tungsten is used as the target material. In this article, the well-known simulator Geant4 was used to obtain some of the tungsten target parameters. The optimal thickness for maximum production of usable X-rays when the target is exposed to electron beams of different energies was obtained. The linear variation of optimal thickness of the target for different electron energies was also obtained. The data obtained in this study can be used to design X-ray tubes. A beryllium window was considered for the X-ray tube. The X-ray energy spectra at the moment of production and after passing through the target and window for different electron energies in the 30-110 keV range were also obtained. The results obtained show that with a specific thickness, the target material itself can act as filter, which enables generation of X-rays with a limited energy.

• Nuclear Engineering and Technology
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• v.50 no.4
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• pp.582-588
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• 2018

Accident diagnosis is one of the complex tasks for nuclear power plant (NPP) operators. In abnormal or emergency situations, the diagnostic activity of the NPP states is burdensome though necessary. Numerous computer-based methods and operator support systems have been suggested to address this problem. Among them, the recurrent neural network (RNN) has performed well at analyzing time series data. This study proposes an algorithm for accident diagnosis using long short-term memory (LSTM), which is a kind of RNN, which improves the limitation for time reflection. The algorithm consists of preprocessing, the LSTM network, and postprocessing. In the LSTM-based algorithm, preprocessed input variables are calculated to output the accident diagnosis results. The outputs are also postprocessed using softmax to determine the ranking of accident diagnosis results with probabilities. This algorithm was trained using a compact nuclear simulator for several accidents: a loss of coolant accident, a steam generator tube rupture, and a main steam line break. The trained algorithm was also tested to demonstrate the feasibility of diagnosing NPP accidents.

• The Journal of Engineering Research
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• v.3 no.1
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• pp.57-64
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• 1998

This paper presents an architecture of a real-time two-dimensional median filter. The architecture has appropriate characteristics for the VLSI implementation such as small memory requirements, regular computations, and local data transfers. For the efficient two-dimensional median filter, a separable two-dimensional median filtering structure and a bit-sliced pipelined median searching algorithm are used. A behavioral simulator is implemented with C language and used for the analysis of the presented architecture.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.477-480
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• 2007

Inlet fluid temperature of the BRE in the geothermal heat pump system depends on heat exchange rate between the refrigerant of the heat pump and the leaving fluid from the BRE. Because the outlet fluid temperature of the BHE varies with time, inlet fluid temperature has to vary with time. In this study, the module to calculate inlet fluid temperature is developed, which can consider the time-varying outlet fluid temperature and the heat exchange capacity of the heat pump. It is assumed that heat loss or gain of the leaving fluid from outlet to inlet of the BHE is negligible, except when the fluid contacts with the refrigerant of the heat pump. This module is combined with TOUGHREACT, a widely accepted three-dimensional numerical simulator for heat and water flow and geochemical reactions in geothermal systems and is applied to data analyses of the thermal response test.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.1
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• pp.54-59
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• 2002

In the three-axis control of satellites by using on-board actuators, gyros are usually used to measure the attitude angles and angular rates. The gyros are operated by electronic parts and mechanical actuators. The digital components of the electronic parts consist of largely FPGA (Field Programmable Gate Array) as one of the methods for VLSI(Very Large Scale Integrated) circuit design, while the mechanical parts provide output signal directly by mechanical actuation of a spinning rotor. In this research, a mixed mode of gyro is implemented in FGA. In addition to the hardware implementation, the simulation study was conducted by using the SABER for the mixed mode simulator. Results for the practical implementation of the satellite ACS (Attitude Control System) interfaced with the data processing are also presented to validate the FPGA implementation.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.65-68
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• 2000

We design a new driving system of 5" true color FED using current controlled PWM method. Further more, we successfully developed a 5" FED panel, which resolution is 320$\times$240(Color). When we design a 5" FED driving circuit, FED tips are modeled as R-C for circuit simulator of FED driving circuit. In Video data processing, parallel R, G, B input signals is processed independently, so duty ratio increase and no noise, high quality performance is achieved in display of 5" FED. The luminance is about 100cd/$m^2$, the anode power consumption Is 2.1W and total power of the driving system is 21.54W

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.265-266
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• 2008

The interest on harmonics which is one of the matters related with power quality problem is not limited in only the system where the large scale industrial load is connected. The harmonics phenomenon not only causes the malfunction of devices, but also lowers the energy efficiency of power system. This paper focuses on the harmonic analysis process to establish the harmonic mitigation method, considering the harmonics distortion as a major cause to reduce the energy efficiency of a skyscraper. A system diagram of building is modelled with PSCAD simulator. Based on the harmonic analysis results of it, the electrical locations with the high priority to install the mitigating devices are selected. Finally, the result of PSCAD simulations and the site-measured data are compared, verifying that they reach a common conclusion.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.177-179
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• 2008

This paper, we proposed the theoretical model which includes series resistance $R_s$ and shunt resistance $R_{sh}$ of single-crystalline PV module and used numerical method based on physics. Series resistance $R_s$ was derived from approach for p-n junction diode instead of established form obtained from the simulator with irradiance changes. Electrical output characteristics for PV modules to count the effect of $R_s$ were then studied. Finally simulation results were compared to experimental data leading to good agreement.