• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3069-3085
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• 1996

This paper shows an accurate charge-pump PLL model which considers the wave-form distortion in high speed operation of charge-pump PLL, the leakage current in loop filter, and a physical limit in charge-pump. With proposed model of charge-pump PLL, overload and stability are derived theoretically and the results are compared to the conventional model. Unlike the ideal charge-pump PLL that simplifies calculations, it is possible to analyze the transient-state and the steady-state at the same time with proposed accurate model. Thus, charge-pump over load, in the transient-state and the stead-state of charge-pump, is accuragely analyzed and the results are confirmed with simulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.1
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• pp.13-17
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• 2013

In this paper, we designed a charge pump circuit using level shifter for LED driver IC. The designed circuit makes the 15 V output voltage from the 5 V input in condition of 50 kHz switching frequency. The prototype chip which include the proposed charge pump circuit and its several internal sub-blocks such as oscillator, level shifter was fabricated using a 0.35 um 20 V BCD process technology. The size of the fabricated prototype chip is 2,350 um ${\times}$ 2,350 um. We examined performances of the fabricated chip and compared its measured results with SPICE simulation data.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.824-833
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• 2012

In this paper, a coordinated state-of-charge (SOC) control strategy for the energy storage system (ESS) operating under microgrid islanded mode to stabilize the frequency and voltage was proposed. The proposed SOC control loop is made up of PI controller, which uses a SOC state of the energy storage system as an input and an auxiliary reference value of secondary control as an output. The SOC controller changes the auxiliary reference value of secondary control to charge or discharge the ESS. To verify the proposed control strategy, PSCAD/EMTDC simulation study was performed. The simulation results show that the SOC of the ESS can be regulated at the desired operating range without degrading the stabilizing control performance by proposed coordinated SOC control method.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.299-302
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• 2013

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.981-984
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• 2005

This study is to realize its threshold voltage shift after programming operation in charge trap type SONOS memory by simulation. SONOS devices are charge trap type nonvolatile memory devices in which charge storage takes place in traps in the nitride-blocking oxide interface and the nitride layer. For simulation of their threshold voltage as a function of the memory states, traps in the nitride layer have to be defined. However, trap models in the nitride layer are not developed in commercial simulator. So, we propose a new method that can simulate their threshold voltage shift by an amount of charges induced to the electrodes as a function of a programming voltages and times as define two electrodes in the tunnel oxide-nitride interface and the nitride-blocking oxide interface of SONOS structures.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.51-59
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• 2002

In this study, cycle simulation was performed to investigate the effect of EGR on combustion characteristics and emissions including NO and soot using a two-zone model in a DI diesel engine. The NO formation was well predicted for different EGR rate and temperature using a two-zone model. The oxygen in the inlet charge was replaced by CO$_2$ and H$_2$O with EGR. The reduction in the inlet charge oxygen resulted in very large reduction in NO level at the same inlet charge temperature. The effect of EGR was to reduce the burned gas temperature. When EGR was increased from 0% to 15%, the peak flame temperature was decreased by 50$\^{C}$ and it caused about 57% NO reduction. EGR caused increase of the overall inlet charge temperature which offset some of benefit of lower flame temperature resulting from O$_2$ displacement. Cooling the EGR was confirmed to provide additional benefits by lowering NO emission. It also reduced soot emission.

• Journal of Korea Foundry Society
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• v.42 no.6
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• pp.347-357
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• 2022

In this study, 3D visualization of the packing behavior of the charge material in a foundry was attempted. It was simulated based on the practical conditions of the charge material and the melting furnace. It was confirmed whether the 3D visual simulation realistically implements the packing behavior of the manufacturing site. The realistic packing state by the 3D visual simulation was compared with the ideal packing state. It was analyzed in which case the difference between the two packing states occurred. The advantages of applying the 3D visual simulation to the manufacturing process were investigated, and various application plans in the casting industry were proposed.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.9
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• pp.341-348
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• 1985

This paper deals with a surface charge simulation method of calculating three-dimensional electric fields and capacitance. The principle is to divide the electrode surface into rectangular or triangular elements of which charge density is the linear function of the electrode coordinate and to formulate a linear equation for the coefficients of charge density function and to determine those coefficients by boundary conditions. It has been shown that the method can give satisfactory results for thin rectangular plates where the other methods is difficult to be applied.

• Journal of information and communication convergence engineering
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• v.9 no.1
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• pp.78-82
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• 2011

This paper proposes a new circuit for capacitive sensing based on Dickson's charge pump. The proposed touch sensing circuit includes three stages of NMOS diodes and capacitors for charge transfer. The proposed circuit which has a simplified capacitive touch sensor model has been analyzed and simulated by Spectre using Magna EDMOS technology. Looking from the simulation results, the proposed circuit can effectively be used as a capacitive touch sensing circuit. Moreover, a simple structure can provide maximum flexibility for making a digitally-controlled touch sensor driver with lowpower operations.

• Journal of the Korea Society for Simulation
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• v.31 no.3
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• pp.11-21
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• 2022

Two methods for analyzing interaction between shaped charge jets and targets are taken in AVEAM-MT (ADD Vulnerability and Effectiveness Assessment Model for Materiel Target), which is a model for vulnerability analysis of materiel targets and being developed by ADD. One is an empirical method improved from the Fireman-Pugh technique for rapid penetration calculation into target components. The other is ADD-TSC(ADD Tandem Shaped Charge), which is a physics-based model extended to be applicable for shaped charge jets from the Walker-Anderson penetration model for higher fidelity analysis. In this paper, the two methods are briefly described, and the empirical technique is compared to the physics-based model in the prediction of residual penetration capacity. The latter is also compared to experimental results found in literature in predicting penetration capacity. These comparisons show that both methods can be used for fast calculations or higher fidelity calculations in vulnerability analysis models like AVEAM-MT which is required to perform a considerable amount of iterative simulation for damage analysis.