• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.69.1-69.1
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• 2019

A series of numerical MHD simulations are performed to investigate the evolution of coronal magnetic fields consisting of two flux ropes and an overlying field. Depending on the directions of the axial current and the axial field, two co-helicity cases and two counter-helicity cases are addressed. In Case 1, in which both the axial currents and the axial fields are parallel, flux rope merging bears a huge flux rope with a large winding number. This flux rope naturally erupts, but the whole evolutionary process is rather slow. In Case 2, in which the axial currents are parallel while the axial fields are antiparallel, a self-closed structure is formed and it drives eruption. In Case 3, in which the axial currents are antiparallel and the axial fields are parallel, each flux rope erupts independently and the presence of the other flux rope does not affect the eruption of one flux rope. In Case 4, in which both the axial currents and the axial fields are antiparallel, interaction of the flux ropes and the overlying field effects a breakout reconnection creating an apple-like CME configuration. Our study tells what kind of eruption mechanisms are involved for different eruption features observed.

• Journal of the Daesoon Academy of Sciences
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• v.18
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• pp.81-99
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• 2004

This text discusses trends in the construction of religions since the Meiji Era, using Konkokyo and Restoration Shintoism as examples. The construction of religions is applied here as the process of a deliberate acceptace of religious images as a discourse of "Civilization" endowed with "kyougi" or "Doctrine" and "kyousoku" or "Rules of Instruction." Winding through a meandering path, these constructed religions do not take precedence over "Jikyou" or "State Religion." Yet, "Jikyou" for a while was fixed in its own fragemented self-imagery. As for Shinto, in 1900, the Office of Shinto Shrines became independent from the Office of Shrines and Temples in the Department of Domestic Affairs, and clearly Shinto and Shinto Shrines were part of secular state ideology. In the Bakumatsu and Meiji Periods, it ultimately was cut off from Restoration Shinto, thereby achieving this development on its own. This tells of the formation of an entirely new and modern Shinto within a secular "Jikyou." Konkokyo, moreover, as a religion establishes "kyousoku" and "kyougi." As a Shinto sect, it takes steps on the path toward recognizing a self-identity, namely as religious Shinto. As a result, dogmatization and systemization progress, and "Byoukinaoshi" or "illness-recovery" from the Tokugawa Period weathers. Also, as for progress in the Shinto religious order, from its foundation, the characteristics of a unified state and religion emerge, and thus there is an acceptance of significant restrictions. This dillema continues to persist as a problem in postwar Japan. Shedding light on Tokugawa Era practice also sheds light on where we can now take religious concepts.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.65-70
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• 2001

We consider a hyper-redundant system that consists of many uniform units. The hyper-redundant system has many degrees of freedom and it can accomplish various tasks. Applysing the reinforcement learning to the hyper-redundant system is very attractive because it is possible to acquire various behaviors for various tasks automatically. In this paper we present a new reinforcement learning algorithm "Q-learning with propagation of motion". The algorithm is designed for the multi-agent systems that have strong connections. The proposed algorithm needs only one small Q-table even for a large scale system. So using the proposed algorithm, it is possible for the hyper-redundant system to learn the effective behavior. In this algorithm, only one leader agent learns the own behavior using its local information and the motion of the leader is propagated to another agents with time delay. The reward of the leader agent is given by using the whole system information. And the effective behavior of the leader is learned and the effective behavior of the system is acquired. We apply the proposed algorithm to a snake-like hyper-redundant robot. The necessary condition of the system to be Markov decision process is discussed. And the computer simulation of learning the locomotion is demonstrated. From the simulation results we find that the task of the locomotion of the robot to the desired point is learned and the winding motion is acquired. We can conclude that our proposed system and our analysis of the condition, that the system is Markov decision process, is valid.

• Composites Research
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• v.31 no.4
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• pp.161-170
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• 2018

Cylindrical composite lattice structures are manufactured by filament winding process. The fiber volume fraction non-uniformity and resin rich layers that can occur in the manufacturing process affect the stiffness and strength of the structure. Through the cross-section examination of the hoop and helical ribs, which are major elements of the composite lattice structure, we observed the fiber volume fraction non-uniformity and resin rich layers. Based on the results of the cross-section examination, the stiffness of the ribs was analyzed through the experimental and theoretical approaches. The results show that the fiber volume fraction non-uniformity and resin rich layers have an obvious influence on the rib stiffness of composite lattice structure.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.539-546
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• 2006

A study on the polymerization of polyethylenedioxythiophene (PEDOT) and the carbonization process of a separator was carred out in order to apply conductive polymer PEDOT to the winding typed aluminum condenser as a solid electrolyte and a negative electrode. PEDOT was polymerized with ethylenedioxythiophene (EDOT) as a monomer and ferric-p-toluenesulfonate as an oxidizing agent. The separator of condenser element was carbonized to control its fibrous tissue for the purpose of making it easy to impregnate the PEDOT solution into the microporous etched pit of aluminum foil by preventing separator from concentrating the PEDOT solution on itself. The characteristics of condenser such as capacitance, dissipation factor, equivalent series resistance, and thermal resistance depended on a carbonization temperature and a carbonization time. It was found that a thickness and a density of the used separator were major parameters of carbonization process and the characteristics of condenser were affected by these parameters.

• Journal of IKEEE
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• v.24 no.1
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• pp.132-139
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• 2020

The ionizer module used in this air cleaner supplies high voltages of 3.5KV / -4KV to the discharge electrode HV+ / HV- using a winding transformer to generate positive and negative ions by electric field radiation of carbon fiber brush. The ionizer module circuit using the existing MCU has the disadvantage of large PCB size and expensive price, and the gate driver chip using the existing ring oscillator has oscillation period sensitive to PVT (Process-Voltage-Temperature) fluctuation and there is risk of fire or electric shock because there is no fault detection function by short circuit of HV+ and GND as well as HV- and GND. Therefore, in this paper, even though PVT fluctuates, by using 7-bit binary up counter, HV+ voltage reaches the target voltage by adjusting oscillation period. And an HV+ short fault detection circuit for detecting a short circuit between HV+ and GND, an HV- short fault detection circuit for detecting a short circuit between HV- and GND, and an OVP (Over-Voltage Protection) for detecting that HV+ rises above an overvoltage are newly proposed.

• Journal of the Korea Safety Management & Science
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• v.16 no.2
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• pp.237-246
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• 2014

Researches on the elimination of sulfur and nitrogen oxides with catalysts and absorbents reported many problems related with elimination efficiency and complex devices. In this study, decomposition efficiency of harmful gases was investigated. It was found that the efficiency rate can be increased by moving the harmful gases together with SPCP reactor and the catalysis reactor. Calcium hydroxide($Ca(OH)_2$), CaO, and $TiO_2$ were used as catalysts. Harmful air polluting gases such as $SO_2$ were measured for the analysis of decomposition efficiency, power consumption, and voltage according to changes to the process variables including frequency, concentration, electrode material, thickness of electrode, number of electrode winding, and additives to obtain optimal process conditions and the highest decomposition efficiency. The standard sample was sulfur oxide($SO_2$). Harmful gases were eliminated by moving them through the plasma generated in the SPCP reactor and the $Ca(OH)_2$ catalysis reactor. The elimination rate and products were analyzed with the gas analyzer (Ecom-AC,Germany), FT-IR(Nicolet, Magna-IR560), and GC-(Shimazu). The results of the experiment conducted to decompose and eliminate the harmful gas $SO_2$ with the $Ca(OH)_2$ catalysis reactor and SPCP reactor show 96% decomposition efficiency at the frequency of 10 kHz. The conductivity of the standard gas increased at the frequencies higher than 20 kHz. There was a partial flow of current along the surface. As a result, the decomposition efficiency decreased. The decomposition efficiency of harmful gas $SO_2$ by the $Ca(OH)_2$ catalysis reactor and SPCP reactor was 96.0% under 300 ppm concentration, 10 kHz frequency, and decomposition power of 20 W. It was 4% higher than the application of the SPCP reactor alone. The highest decomposition efficiency, 98.0% was achieved at the concentration of 100 ppm.

• Journal of the Korean Institute of Gas
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• v.13 no.6
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• pp.29-33
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• 2009

In this study, the strength safety of a composite fuel tank which is fabricated by an aluminum liner of Al6061-T6 materials and composite layers of carbon/epoxy-glass/epoxy composites has been analyzed by using a finite element analysis technique. In order to enhance the durability of the composite fuel tank, an autofrettage process was used and compressed natural gas was supplied to the prestressed fuel tank. The FEM computed results on the stress safety of autofrettaged gas tanks were compared with a criterion of design safety of US DOT-CFFC and Korean Standard. The FEM computed results indicated that the stress safety of autofrettaged fuels tanks shows instability at the dome zone and uniform stability at the parallel body, which provide an evaluation data for a strength safety of autofrettaged composite fuel tanks. The computed results show that the stress safety of 9.2 liter composite fuel tanks satisfied the safety criteria of four evaluation items, which are provided by US DOT-CFFC and KS and indicated a safe design.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.111-116
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• 2022

The causes of motor burnout include overload, phase loss, restraint, interlayer short circuit, winding ground fault, instantaneous overvoltage, and the rotor contacting the stator, leading to insulation breakdown, leading to breakdown or electrical accidents. Therefore, equipment failure causes not only loss due to cost required for equipment maintenance/repair, but also huge economic loss due to productivity decrease due to process stop because the process itself including the motor is stopped. The current level of technology for diagnosing motor failures uses vibration, heat, and power analysis methods, but there is a limit to analyzing the problems only after a considerable amount of time has passed according to the failure. Therefore, in this paper, a device and algorithm for measuring insulation resistance using DC AMP signal was applied to an industrial motor to solve this problem. And by following the insulation resistance state value, we propose a diagnosis of deterioration and failure of the motor that cannot be solved by the existing method.

• Progress in Superconductivity
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• v.3 no.1
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• pp.130-133
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• 2001

A multifilamentary Bi-2223 HTS tape for superconducting power applications was studied through the fabrication of 250-meter long tapes by the PIT(powder in tube) process. To fabricate continuous long wire, a drawing machine, a two-drum bull block and a rolled tape winding machine were developed. Especially, 250-meter long tapes were heat treated in the shape of pancake coil to reduce the heat affect zone and to achieve the high critical current. Engineering critical current density was improved through both the enhancements of critical current density by control of thermal process and the increase of filling factor by using thin Ag alloy sheath tubes less than 1.5 mm in thickness. We have made successfully 250-meter long 37 filamentary tapes with high filling factor up to 31 % employing the modified drawing and rolling technique. The critical current of 250-meter long tapes with pancake coil type was measured by transport method at self-field up to 250 gauss of center field. The measured values, based on the transport critical current at self-field, $I_{c}$ -B characteristics and magnetic field analysis, are 34 A of I$_{c}$ and 4.0 $kA/\textrm{cm}^2$ of $J_{e}$ at 250 m, 77 K, and 0 T. We also have achieved the 56 A of I$_{c}$ and 7.0 $0 kA/\textrm{cm}^2$ of$ J_{e}$ in short tapes at 77K, self-field, and 1$mutextrm{V}$/cm.