• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1060-1066
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• 2021

Recently, researches for quantum computers have been carried out in various fields. Quantum computers performs calculations by utilizing various phenomena and characteristics of quantum mechanics such as quantum entanglement and quantum superposition, thus it is a very complex calculation process compared to classical computers used in the past. In order to simulate a quantum computer, many factors and parameters of a quantum computer need to be analyzed, for example, error verification, optimization, and reliability verification. Therefore, it is necessary to visualize circuits that can intuitively simulate the configuration of the quantum computer components. In this paper, we present a novel visualization method for designing complex quantum computer system, and attempt to create a 3D visualization toolkit to deploy large circuits, provide help a new way to design large-scale quantum computing systems that can be built into future computing systems.

• Journal of the Korean Society of Visualization
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• v.14 no.2
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• pp.52-60
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• 2016

The Passive Auxiliary Feedwater System(PAFS) is one of the advanced safety concepts adopted in the Advanced Power Reactor Plus(APR+). To validate the operational performance of the PAFS, detailed understanding of a boiling heat transfer on horizontal tube outside is of great importance. Especially, in the mechanistic boiling heat transfer model, it is important to visualize the phenomena but there are some limitations with conventional experimental approaches. In the present study, we devised a heater based on the Flexible Printed Circuit Board (FPCB) for a more comprehensive visualization and subsequently, a digital image processing technique for the bubble motion measurement was established. Using the measurement technique, important parameters of the nucleate boiling are analyzed.

• 한국가시화정보학회:학술대회논문집
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• 2004.11a
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• pp.48-51
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• 2004

Chemical Mechanical Polishing(CMP) is popularly used in production of semiconductor because of large area polishing ability probability of improvement for more integrated circuit. However, present CMP processing causes some non-uniformity errors which can be critical for highly integrated circuit. Previous studies predict that flow-field of slurry during CMP can create non-uniformity, but no quantitative measurement has conducted. In this study, using PIV, slurry velocity flow-field during CMP is measured by changing the ratio of RPM of pad and carrier with tuned PIV system adequate for small room in CMP machine and Cabot's non-groove pad Epad-A100. The result show that velocity of slurry is majorly determined by pad-rpm and the ratio of between carrier and pad rpm make some changes in streamlines.

• Journal of the Korean Society of Visualization
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• v.7 no.2
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• pp.17-21
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• 2010

This paper presents the fabrication and performance measurement of a temperature sensor array on a flexible substrate attachable to a curved surface using MEMS technology. Specifically, the fabrication uses the well-developed printed circuit board fabrication technology for complex electrode definition. The temperature sensor array are lifted off with a $10{\times}10$ matrix in a $50\;mm{\times}50\;mm$ to visualize temperature distribution. Copper is used as temperature sensing material to measure the change in resistances with temperature increase. In a thermal oven with temperature control, the temperature sensor array is Characterized. The constant slope of resistance change is obtained and temperature distribution is measured from the relationship between resistance and temperature.

• Journal of Electrical Engineering and Technology
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• v.1 no.2
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• pp.145-152
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• 2006

This paper presents a windows application for voltage sag analysis and effective data visualization. The developed Voltage Sag Analysis Tool (VSAT) was designed by using the Object-Oriented Programming (OOP) concept and C++ programming language. The VSAT provides basic functions for voltage sag analysis such as power flow analysis, short circuit analysis and stochastic analysis. In particular, the VSAT provides effective data visualization through computer graphics and animation. Analysis results are expressed realistically and intuitively on geographical display. The Graphic User Interface (GUI) of VSAT was designed specifically for voltage sag analysis. In this paper, the development and implementation of VSAT is presented. In order to demonstrate the capabilities of VSAT, it is used to analyze the Jeju Island power system in South Korea.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.7
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• pp.297-305
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• 2006

This paper summarizes a development of visualization software for protective engineering in low-voltage power systems. The study is concentrated on the following aspects. First, a software engineering method is applied for designing the object-oriented program. The design and implementation of a Graphic User Interface(GUI) and its integration to a power system framework are developed using object-oriented programming(OOP) in Visual C++. Second, we develop the short circuit analysis module that oriented a low-voltage power system. It is possible to calculate a peak, symmetrical RMS, DC component and asymmetrical fault currents for each time. And it is the first software that can calculate the fault current for single branch of three-phase system. The calculation accuracy is compared with commercial software, and the libraries of low-voltage components are served for convenience use. Third, protective engineering functions are equipped. It is possible to automatically select the circuit breaker which based on the user input characteristics and the fault current calculation and examine the protective coordination. Through the case study, we verified that the developed software can be effectively used to examine the protective engineering in low-voltage power systems.

• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.69-76
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• 2021

Printed circuit heat exchanger (PCHE) is a compact heat exchanger with good heat transfer performance, high structure integrity, and reliability over a wide range of temperatures and pressures. Instead of the traditional zigzag and straight shape channel, the sinusoidal shape channel was adopted in this study to investigate the relation of thermal-hydraulic performance and waviness factors (period and amplitude). The local flow characteristics and the heat flux distribution were compared to verify the effects of period and amplitude on heat transfer performance. As the period of channel becomes shorter, the rapid change of the flow direction can produce high flow separation around the corner leading to the disturbance of the boundary layer opposite wall. The nonuniform distribution of flow velocity appeared around the corner positions can promote fluid mixing and lead to higher thermal performance. An evaluation index was used to compare the comprehensive performance of PCHE considering the Nusselt number and Fanning factor. Based on the simulation results, the optimal design parameters of PCHE channel shape were found that the channel with an equivalent bending angle of 15° offers the highest heat flux capacity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.611-613
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• 2021

Recently, research and development of quantum computers, which exceed the limits of classical computers, have been actively carried out in various fields. Quantum computers, which use quantum mechanics principles in a way different from the electrical signal processing of classical computers, have various quantum mechanical phenomena such as quantum superposition and quantum entanglement. It goes through a very complicated calculation process compared to the calculation of a classical computer for performing an operation using its characteristics. In order to utilize each element efficiently and accurately, it is necessary to visualize the data before driving the actual quantum computer and perform error verification, optimization, reliability, and verification. However, when visualizing all the data of various elements configured inside the quantum computer, it is difficult to intuitively grasp the necessary data, so it is necessary to visualize the data selectively. In this paper, we visualize the data of various elements that make up a quantum computer, and hierarchically visualize the internal circuit components of a quantum computer that are complicatedly configured so that the data can be observed and utilized intuitively.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.11
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• pp.1211-1216
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• 2013

In this study, a dynamic camera actuation system for simultaneous in situ image acquisition is developed to achieve real-time observation of transient liquid flow on a lab-on-a-disk. A disk-type electric circuit, namely circuit-on-a-disk, co-rotated with the lab-on-a-disk improves the dynamic image acquisition ability in terms of a frame rate. The circuit-on-a-disk is comprised of a camera connected with a motor, a microprocessor and a wireless communication module. The camera connected with the motor enables to realize dynamic tracking of a transient flow and real-time image acquisition. The obtained images can be simultaneously transferred by a video/audio transmitter unit to a personal computer. Also, the microprocessor receives signals from the personal computer, and then controls the focusing position of the camera. We are expecting that heaters, sensors, and light sources also can be integrated on the circuit-on-a-disk, and they will enable various functional actuations as well as precise image acquisition.

• Journal of Advanced Marine Engineering and Technology
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• v.10 no.3
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• pp.107-118
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• 1986

The presenet research attempts to examine the combustion characteristics and the structure of the flame in turbulent premixed flames and thus enhance the combustion performance that leads to the design of the effective combustion system (untilizing LNG). Following experimental investigations for several stabilized premixed flames were attempted to identify the interactive mechanism between flame structures and flow fields; Visualization by Schlieren method, measurement of flow velocity by LDV, detection of ion current by ion probe, measurement of fluctuating temperature by thermocouple having compensation circuit, average values with respect to time of fluctuating amount for flow velocity, temperature, ion current, etc., variable RMS values, PDFs, autocorrelation, crosscorrelation, spatial macroscale, power spectra, and velocity scale. Continuing the authors published studies whose flame dominated by coherent structures and the characteristics of combustion reaction for irregular three dimensional flame and stabilized flame by step were investigated with obtained experimental quantities. Results of this research are following : The most turbulent flames support the structure of a Wrinkled laminar flame or laminar flamelets. It also observed that combustion reaction is related to small tubulence microscales of the turbulent flow fields closly.