• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1132-1141
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• 2006

Recently it is difficult to secure sand used in the improvement of soft ground, and so it is necessary to find alternative materials. For this reason many researchers are studying and trying to find new substitute materials. One of the materials is considered as converter slag by wind fracture which is generated in the production of steel manufacture by electric circuit. It is environment friendly since it is a recycled material and economical since it is cheaper than sand. To investigate the applicability of converter slag by wind fracture as the alternative material such as vertical drains, it is necessary to check the drainage effect of this in the field construction. In order to attain an successful design it is important to predict problems encountered in field construction. Accordingly, in this study the laboratory test was executed under different conditions in advance of applying of the field. A total of 4 cases including slag, sand+slag, pack slag and sand as vertical drains was conducted, and at the base of the laboratory test the field test was executed and analyzed.

• Journal of IKEEE
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• v.19 no.4
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• pp.617-624
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• 2015

In this paper, an adult authentication system based on authentication certificate was designed and implemented using smartphone and near-field communication. It has three advantages. First, it achieves easy, convenient, and fast authentication by using smartphone and near-field communication. Second, it achieves extremely high security and reliability by exploiting authentication certificate. Third, it achieves extremely low risk of personal information leakage by generating and sending only virtual identification code. Finally, it has a proper legal basis by Digital Signature Act. It consists of adult authentication module, near-field communication control module, policy server module, and database server module. A prototype of the proposed system was designed and implemented, and it was verified to have correct operation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.1044-1051
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• 2020

The age of quantum computers is coming soon. In order to prepare for the upcoming future, the National Institute of Standards and Technology has recruited candidates to set standards for post quantum cryptography to establish a future cryptography standard. The submitted ciphers are expected to be safe from quantum algorithm attacks, but it is necessary to verify that the submitted algorithm is safe from quantum attacks using quantum algorithm even when it is actually operated on a quantum computer. Therefore, in this paper, we investigate an efficient quantum gate implementation for binary field multiplication of code based post quantum cryptography to work on quantum computers. We implemented the binary field multiplication for two field polynomials presented by Classic McEliece and three field polynomials presented by ROLLO in generic algorithm and Karatsuba algorithm.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.2
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• pp.43-52
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• 2008

The galvanic corrosion of a vessel, or systems fitted to minimize the ship's corrosion such as ICCP (Impressed Current Cathodic Protection) system and sacrificial anodes, can lead to significant electrical current flow in the sea. The presence of vessel's current sources associated with corrosion will give rise to detectable electric field surrounding the vessel and can put it at risk from mine threats. For this reason, it is necessary to design corrosion protection systems so that they don't only prevent a hull corrosion but also minimize the electric field signature. In this paper, we describe theoretical backgrounds of underwater electric field signature due to corrosion and corrosion protection system on naval vessels and analysis results of the electric field according to the ship's hull and it's propeller coating damage and ICCP anode displacement.

• Journal of Sensor Science and Technology
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• v.26 no.3
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• pp.186-191
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• 2017

In this study, we investigated the simultaneous detection properties of organic vapor, pressure difference, and magnetic field using a single rugate-structured free-standing porous silicon (RFPS) thin film. Both the wavelength and the intensity of the rugate peaks were changed in the reflectivity spectrum measured at the thin film surface while the organic vapor was exposed to the RFPS thin film. However, when the pressure difference and the magnetic field were exposed to the film, only the rugate peak intensity was changed. Therefore, it is possible to distinguish whether or not the organic vapor is detected by simultaneously changing the rugate peak wavelength and intensity. In addition, a method of distinguishing between the pressure difference and the magnetic field detection signal has been derived by rapidly modulating the direction of the magnetic field. This study shows that it is possible to simultaneously detect and distinguish various objects using a single RFPS thin film, and it is found that porous silicon can be utilized as a sensor sufficiently.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1641-1645
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• 2012

In this study, the ZnO nanorod is grown on the seed layered glass substrate by applying an external electric field to fabricate the ZnO nanorod with the high quality and to increase the yield of the ZnO nanorod. It is possible to grow the definite and clear hexagonal ZnO nanorod as the cathode of the high voltage is connected to the side of the seed layered glass substrate and the anode is connected to the opposite side because more $Zn^{2+}$ ions are located around the ZnO seed layer and are accumulated easily due to the external electric field. As a result, it is succeeded to fabricate the definite hexagonal ZnO nanorod having better structural characteristics by applying the external electric field during the growth process. Therefore, it is demonstrated that the external electric field is effective to fabricate the high quality ZnO nanorod without changing any composition of the ZnO nanorod.

• Economic and Environmental Geology
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• v.17 no.2
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• pp.141-147
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• 1984

For the discussion of palaeogeomagnetic field direction and the movement and rotation of geotectonic blocks it is prerequisite to eliminate the secondary remanent magnetization component out of the NRM vector of given rock samples. Among various techniques alternating field and thermal demagnetization methods are most easily applicable and most widely used ones. Physical principle underlying these methods is the concept of relaxation time: Either with an action of external magnetic field or with an elevated temperature relaxation time of magnetic minerals can be drastically shortened. It has been furthermore shown experimentally that the secondary remanent magnetization can be more easily demagnetized than the primary remanent magnetization. Through careful stepwise demagnetization it should also be possible to discriminate the kind of various remanent magnetizations. In addition to the introduction to the underlying physical principles and experimental results of the alternating field and thermal demagnetization this paper gives various practical tips in earring out the demagnetization experiments. Each alternating field and thermal demagnetization instrumentation which is easily adaptable to domestic palaeomagnetic laboratories is also introduced. This paper provides a compact and practical introduction to the methods in palaeomagnetism and would be of interest to present workers and to those who want to embark on research in this field.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.873-875
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• 2003

It is well known that $I_c$ (critical current) in HTS tape is more sensitive to $B{\perp}$ (magnetic field amplitude applied perpendicular to the tape surface) than to B// (magnetic field amplitude applied parallel to the tape surface). Thus, the magnitude of $B{\perp}$ at HTS tape is important to the design of HTS motor, because it determines the operating current. In addition, the $I_c$ of HTS field coil is determined by not only the $B{\perp}$ but also stress and strain condition at given operating temperature. Therefore, at the stage of field coil design, stress and strain conditions should be considered because when the HTS tape is handled, it is necessary to know the limiting values of loading, bending and twisting to avoid any damages. The $I_c$ of field coil is calculated by 3D analysis and measured through experiments considering the $B{\perp}$ and the margin of contacts loss.

• Journal of the Korean Geotechnical Society
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• v.24 no.10
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• pp.113-120
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• 2008

It is difficult to acquire good-quality fill material for levee in field and it is the most important factor of levee construction technology to use the bed sediment for the safe and economic construction. So, it is necessary to evaluate geotechnical characteristics of bed sediment, design and construction method through field application tests. In this study geotechnical characteristics of Hyunpoong bed sediment (SP) in Daegu were analyzed, and laboratory/field compaction test for mixing granite weathered soil (SW) was performed. And field mixing method was suggested.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.121-124
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• 2008

This paper presents the fabrication and field emission of carbon nanotube field emitters for a micro mass spectrometer. The carbon nanotube is an adequate material as a field emitter since it has good characteristics. We have successfully fabricated a diode field emitter and a triode field emitter. Each field emitter has been constructed using several micromachining processes and a thermal CVD process. In the case of the diode field emitter, to increase the electric field, the carbon nanotubes are selectively grown on the patterned nickel catalyst layer. The electron current of the diode field emitter is 73.2 ${\mu}A$ when the anode voltage is 1100V. That of the triode field emitter is 3.4 pA when the anode voltage is 1000V.