• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.11-16
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• 2016

Silicon carbide (SiC) has received significant attention over the past decade because of its high-voltage, high-frequency and high-thermal reliability in devices compared to silicon. Especially, a SiC Schottky barrier diode (SBD) is most often used in low-voltage switching and low on-resistance power applications. However, electric field crowding at the contact edge of SBDs induces early breakdown and limits their performance. To overcome this problem, several edge termination techniques have been proposed. This paper proposes an improvement in the breakdown voltage using a double-field-plate structure in SiC SBDs, and we design, simulate, fabricate, and characterize the proposed structure. The measurement results of the proposed structure, demonstrate that the breakdown voltage can be improved by 38% while maintaining its forward characteristics without any change in the size of the anode contact junction region.

• Journal of Environmental Science International
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• v.27 no.8
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• pp.621-629
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• 2018

Many chemically active species such as ${\cdot}H$, ${\cdot}OH$, $O_3$, $H_2O_2$, hydrated $e^-$, as well as ultraviolet rays, are produced by Dielectric Barrier Discharge (DBD) plasma in water and are widely use to remove non-biodegradable materials and deactivate microorganisms. As the plasma gas containing chemically active species that is generated from the plasma reaction has a short lifetime and low solubility in water, increasing the dissolution rate of this gas is an important challenge. To this end, the plasma gas and water within reactor were mixed using the air-automizing nozzle, and then, water-gas mixture was injected into water. The dissolving effect of plasma gas was indirectly confirmed by measuring the RNO (N-Dimethyl-4-nitrosoaniline, indicator of the formation of OH radical) solution. The plasma system consisted of an oxygen generator, a high-voltage power supply, a plasma generator and a liquid-gas mixing reactor. Experiments were conducted to examine the effects of location of air-automizing nozzle, flow rate of plasma gas, water circulation rate, and high-voltage on RNO degradation. The experimental results showed that the RNO removal efficiency of the air-automizing nozzle is 29.8% higher than the conventional diffuser. The nozzle position from water surface was not considered to be a major factor in the design and operation of the plasma reactor. The plasma gas flow rate and water circulation rate with the highest RNO removal rate were 3.5 L/min and 1.5 L/min, respectively. The ratio of the plasma gas flow rate to the water circulation rate for obtaining an RNO removal rate of over 95% was 1.67 ~ 4.00.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.535-541
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• 2004

For housing estate of a new administrative capital city, Noise reduction method is a important design factor. As measuring a noise level of traffic noise according to separation from road, it can be created a quite housing estate. Analyzing of merits and demerits in sound barrier walls and tunnels can be proposed environment friendly soundproofing facilities. Number of measurement was performed to know what kind of layout of housing estate is good for noise reduction. Through this measurement, ㄷ shaped layout or parallel layout has the advantage of sound insulation rather than right angled layout. In this case (ㄷ shaped layout or parallel layout) buildings neighboring to the road should be designed to insulate sound. Evergreen trees should be planted between housing estate and road more than 30m (at least 7～8m) in order to reduce noise and have masking effects. If broad-leaved trees are planted more than 30m, approximately 10dB noise is reduced and 2～4dB if 7～8m. Roads in the estate should be designed considering pedestrians first, and special roads for moving and ambulance should be designed as skew road, if possible. The result shows that 15$^{\circ}$-sloped‘S’road reduces 1～2dB noise and 30$^{\circ}$-sloped road reduces 4～7dB. If noise barrier is inevitably installed, it should be designed to go well wit neighboring environment so as to install Environment Friendly Noise Barrier using materials and trees including wood and soil. Through this study the results are used to guideline for construction of environment friendly housing estate

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.27-36
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• 2016

Houses have usually been planned for those who are in good physical condition rather than with disabilities. Therefore, it is difficult to provide a high quality residential environment for people with disabilities. To live in their own houses continuously, it is essential to renovate their houses where they have been living. This study focuses on removing the barrier factors from houses by analyzing the characteristics of disability types and purpose of each space. Therefore, this study divides a house into 5 sectors: an accessible path; an entrance hall; a corridor; a living room; and a bedroom to remove the barrier factors from each sector according to the analysis above. As a result, the sectors that show high frequency and importance of renovation should be considered as a top priority for renovation.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.163-174
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• 1999

This paper presents a case history of remedial action adopted for contaminated groundwater in a landfill. The objectives of the projects are : (1) to effectively confine contaminated groundwater with an economically reasonable means, (2) to prevent further contamination of soil by collecting and treat the contaminant. and (3) to assure the environmental safety of the landfill during its operating period. Reported are the process from site investigation, through design and construction of an appropriate remedial action, to the monitoring of the selected confinement system. In view of the results of site investigation, deep soil mixing cutoff wall using the DMW(deep soil mixing cutoff wall) method and specially produced HEC soil stabilizer were used for the construction of deep soil mixing cutoff wall. For rock foundation with sever fractures, chemical grout curtain with urethane was installed. The monitoring results to date indicate that the selected vertical barrier performed satisfactorily.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.3
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• pp.202-210
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• 2016

A thermal barrier coating (TBC) has been widely applied to machine components working under high temperature as a thermal insulator owing to its critical financial and safety benefits to the industry. However, the nondestructive evaluation of TBC damage is not easy since sensing of the microscopic change that occurs on the TBC is required during an evaluation. We designed an eddy current probe for evaluating damage on a TBC based on the finite element method (FEM) and validated its performance through an experiment. An FEM analysis predicted the sensitivity of the probe, showing that impedance change increases as the TBC thermally degrades. In addition, the effect of the magnetic shield concentrating magnetic flux density was also observed. Finally, experimental validation showed good agreement with the simulation result.

• Women's Health Nursing
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• v.16 no.2
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• pp.105-115
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• 2010

Purpose: The purpose of this study was to determine the effects of an environmental enrichment program on barrier, benefit, confidence, and compliance of breast self-examination in women at 3 months after instruction. Methods: Nonequivalent control group pretest-posttest design was conducted among 62 healthy women. Data were collected through the self-reported questionnaires from December 2008 to March 2009. Women were assigned to one of two treatment groups: (a) no-support of environmental enrichment with the instruction control group; (b) the support of environmental enrichment with the instruction experimental group. All women received the same instruction on breast self-examination once a week for two weeks. Data were analyzed with paired t-test, McNemar test and ANCOVAs of controlling for age run using SPSS/WIN 17.0. Results: The experimental group was significantly lower than control group on perceived barrier (F=5.91, p=.02) and higher than control group on compliance of breast self-examination (F=4.57, p=.04) after environmental enrichment program. However the environmental enrichment program did not make significant differences on benefit (F=0.01, p=.91) and confidence (F=0.77, p=.38). Conclusion: Findings suggest that the environmental enrichment should be needed to support women's breast self-examination and expanded for compliance of breast self-examination to promote the secondary prevention of women breast cancer.

• Journal of Convergence for Information Technology
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• v.11 no.3
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• pp.132-139
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• 2021

The response characteristics of the forced vibration generated when the high-damped vehicle pass the bumped barrier was studied, and in particular, the response behavior of displacement, velocity and acceleration was analyzed for the forced vibration model. In addition, in order to obtain responses such as displacement, velocity, and acceleration, a numerical analysis technique of the Runge-Kutta-Gill method was performed in time domain. The response was successfully obtained in detail under several high damping conditions. As a numerical analysis result, the response of the vehicle was obtained by considering the vehicle body to which the impulse impact was applied. Also, the analysis result was compared with the experimental result in order to verify the validity of vehicle model. The amplitude and natural frequency of the vehicle were considered and analyzed. The Nyquist diagram of the vehicle model was also obtained and the relationship could be analyzed. And the vibration response was analyzed on different mass, damping and stiffness.

• Journal of the Korea Society of Computer and Information
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• v.28 no.11
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• pp.147-154
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• 2023

In this paper, we propose a barrier-free course route navigation service named "Theme Road" aimed at improving the mobility and convenience for elderly electric wheelchair users with walking disabilities. To achieve this goal, we conducted a user survey through shadowing and in-depth interviews to gather insights on the challenges experienced by elderly electric wheelchair users. We identified potential solutions for each inconvenience through co-creation workshops, resulting in a set of design considerations and app functionalities. Using persona development and service scenarios, we designed and implemented the "Theme Road" service as a dedicated navigation application for barrier-free course navigation. Unlike conventional route navigation and mapping services, our study stands out by offering a unique approach that combines recommended destinations and safe routes based on experiential analysis from elderly electric wheelchair users.

• Journal of Korean Library and Information Science Society
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• v.42 no.4
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• pp.181-201
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• 2011

The recent diversification of society surrounding libraries is influencing the services of libraries. This study suggested the directions of public library services from the aspect of the universal design based on the analysis of related systems and cases to provide all users with universal services in accord with the nature of public libraries amid rapidly changing social environment. This study suggests four directions: the "universal design" which is the keyword for pursuing universality of public library services; the pursuit of economic value of public library services based on the universal design; the universal design for the improvement of perception of public library services; change in policies and systems related to public library services through the application of the universal design.