• The Journal of the Acoustical Society of Korea
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• v.29 no.3
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• pp.173-183
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• 2010

In this paper, acoustic transmission characteristics are theoretically considered on a cylindrical cavity system. The cylindrical cavity system is a simplified model of the acoustic cavity of King Seongdeok Divine Bell and it consists of a main cavity, a gap and an auxiliary cavity, Under a point sound source in the main cavity, acoustic frequency response property is determined and acoustic modes are analysed. The results are compared with those by the boundary element analysis using SYSNOISE. Using the proposed theoretical method, the effect of the auxiliary cavity and the gap on the resonance frequency and sound transmission characteristics is identified. Finally the best combination of the auxiliary cavity and gap is determined for the maximum transmission of the source frequency.

• Journal of the Korean Society of Radiology
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• v.10 no.6
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• pp.403-409
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• 2016

MRI scan is a useful method in the diagnosis of musculoskeletal excellent contrast of the organization. Depending on the patient's musculoskeletal examinations state the type of aids provided the aid is used there is also challenging as well as the costs do not vary. This study was produced by the use of 3D printing technology, an MRI aids. Aids in the production process, then through 3D modeling and then convert stl files using (3D MAX.2014, Fusion360) slicing programs (Cubicreater 2.1ver., Cura 15.4ver) converted to G-code printed on the FDM scheme (Cubicon Style, output was MICRO MAKE). Output is, but in the FDM to evaluate the SNR on the MRI images were compared to the test is the case before use, and then to produce a Water Phantom case of a PLA, ABS, a TPU thickness 3mm, using aids before, It was evaluated in a clinical image after qualitatively. Obtaining an image of SNR Warter Phantom appeared to have been evaluated as T1 NON $123.778{\pm}28.492$, PLA $123.522{\pm}28.373$, ABS $124.461{\pm}25.716$, TPU $124.843{\pm}27.272$. T2 NON $127.421{\pm}26.949$, was rated as PLA $124.501{\pm}27.768$, ABS $128.663{\pm}26.549$, TPU $130.171{\pm}25.998$. The results did not show statistically significant differences. The use of assistive devices before and after images Clinical evaluation method palliative $3.20{\pm}0.88$, $3.95{\pm}0.76$ after using the aids used to aid improved the quality of the image. Production of the auxiliary mechanism using a future 3D printing is expected are thought to be used clinically, it can be an aid making safe and comfortable than the inspection of the patient is an alternative to improve the problems of the aids used in the conventional do.

• Korean Journal of Child Education & Care
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• v.18 no.2
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• pp.85-102
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• 2018

The purpose of this study is to determine the working conditions and demands of the assistant workforce at childcare centers, and to provide suggestions on policies for childcare teachers. To achieve the purpose of the study, a total of 190 assistant teachers, nursing helpers, alternative teachers and others were surveyed online during the month of August 2017. The survey examined the employment route and working motives, working conditions and environment, job and educational difficulties for analyzing the work conditions and demands of ancillary staff. For the analysis method, SPSS 12.0 was used to analyze frequency and difference. The main findings are as follows. First, childcare center assistants were able to work at their respective times, making it mandatory for them to enter the workforce, and making job openings for ancillary teachers. Second, 73.7% said the daily working hours were '4 hours to 8 hours' under the conditions and 57.9% said 'More than 510,000 won to less than 1 million won.' Average amount of rest time per day was about 30 minutes, and 17% had no rest periods. Third, based on the job and education status, ancillary personnel performed "infant and child guidance and interaction", "Cleaning and cleanliness related tasks" most actively, and "care for cleaning and cleanliness" and "care for morning and night care". Fourth, in the job trouble and difficulty, ancillary staff found it difficult to satisfy with wage related complaints and job insecurity, and the reason for agreeing to the non-regular workforce becoming a regular worker was found to be due to the stability of employment. Lastly, the most urgent tasks to solve the problem of non-regular workers were to fill the wage gap between regular and irregular workers, shorten the working hours and improve the working conditions. The policy implications are presented based on the above findings.

• Journal of Korean Society of Transportation
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• v.33 no.5
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• pp.441-448
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• 2015

This study aims to suggest a reasonable signal operation method for right-turn traffic management. It was found that the right-turn vehicle supplementary signal is currently operated without clear regulations or criteria. It was also analyzed that right-turn supplementary signals are used without consistency, there is a risk of traffic accidents due to the discordance between supplementary signals and traffic signals of forward vehicles, there is a lack of basis for prohibition of a right turn when right-turn vehicle's supplementary signal is red and the flashing red signal is used in a different sense from the law. In order to see the effect of the installed right-turn vehicle supplementary signals on traffic signal violation, a field investigation was conducted. As the result, there was a high proportion of signal violation on the approach lane with right-turn supplementary signals and this means that right-turn supplementary signals hardly influenced the reduction in proportion of signal violation during a right turn. Additionally, a survey was carried out to see if there were differences in driver's interpretation of traffic signals depending on the installation of right-turn supplementary signals. As the result of the survey, there were no differences in interpretation of traffic signals depending on the installation of right-turn supplementary signals or the types of right-turn supplementary signals. A right turn when the signal was red did not lead to serious traffic accidents, so it is thought that there should be a careful consideration of a total ban on a right turn when the signal is red, in order to prevent driver's confusion due to the change of the signal system. Unless there is a disturbance to cars and pedestrians after a temporary stop when the signal is red, there is a need to specify that vehicles must stop temporarily in the Road Traffic Act to facilitate a right turn. What this study finally suggested is to use tri-colored arrow signals for right-turn car supplementary signals to convey a signal to a driver clearly.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.613-621
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• 2019

The purpose of this study is to evaluate the effectiveness of supportive devices which are for minimizing the patient's movement during lower extremity angiography and to verify image quality of phantom by analyzing of Mask image, DSA image and Roadmap image into SNR and CNR. As a result of comparing SNR with CNR of mask image obtained by DSA technique using the phantom alone and phantom placed on the supportive devices, there was no significant difference between about 0~0.06 for SNR and about 0~0.003 for CNR. The study showed about 0.11~0.35 for SNR and 0.016~0.031 for CNR of DSA imaging by DSA technique about only water phantom of the blood vessel model and the water phantom placed on the device. Analyzing SNR and CNR of Roadmap technique about water phantom on the auxiliary device (hardboard paper, pomax, polycarbonate, acrylic) and water phantom alone, there was no significant difference between 0.02~0.05 for SNR and 0.002~0.004 for CNR. In conclusion, there was no significant difference on image quality by using supportive devices made by hardboard paper, pomax, polycarbonate or acryl regardless of whether using supportive devices or not. Supportive devices to minimize of the patient's movement may reduce the total amount of contrast, exam-time, radiation exposure and eliminate risk factors during angiogram. Supportive devices made by hardboard paper can be applied easily during angiogram due to advantages of reasonable price and simple processing. It is considered that will be useful to consider cost efficiency and types of materials and their properties in accordance with purpose and method of the study when the operator makes and uses supportive devices.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.69-70
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• 2016

본 논문에서는 공진형 DC/DC Converter와 Single-Switch Boost Converter 구조를 적용한 철도차량용 보조전원장치를 제안한다. 제안하는 회로는 기존 대비 반도체 소자의 개수 저감 및 반도체 소자의 전압 스트레스를 해당 회로부 입력전압의 1/2 이하로 저감 가능하여 낮은 내압의 반도체 소자를 적용할 수 있다. 150kW급 철도차량용 보조전원장치 회로를 컴퓨터 기반 시뮬레이션을 통해 검증하였다.

• 한국정보교육학회:학술대회논문집
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• 2010.01a
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• pp.343-346
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• 2010

최근 지능형 교육서비스로봇을 이용한 교육적 효과가 입증되면서, 유치원에 상용화가 시작되었으며, 2010년에는 초등학교 방과후 학교 영어수업을 위한 기술 개발과 필드 적용 연구가 진행되어 로봇보조학습, 즉 서비스로봇에 의한 r-Learning 패러다임의 본격적인 도래를 예고하고 있다. 이에 본 연구에서는 교육용 로봇의 개념과 종류를 정의하고, 관련 연구 동향을 살펴보았다.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2009.05a
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• pp.190-195
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• 2009

자동차 이용자 수가 증가 할수록 자동차 사고로 인한 피해도 많이 늘어나고 있다. 이러한 자동차 사고를 사전에 예방하기 위해서는 운전자의 상태 및 현재 차량 상태를 파악하여 사고를 미리 방지함으로서 운전자의 안전을 보조할 수 있는 시스템이 필요하다. 본 연구에서는 안전운전을 보조하기 위하여 졸음운전 여부 감지 시스템, 후진시 후방 안전거리를 감지하는 시스템, 쾌적한 운전 환경을 위한 실내 환경 측정 시스템, 주차 시 생길 수 있는 사고에 대한 감시시스템을 센서와 MCU등을 이용한 임베디드 시스템을 구현 하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.37-39
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• 2007

고속 활주형선의 선형시험 ${\cdot}$ 검증을 위하여 설 해상모형시험기법을 정립하였으며, 본 시험법을 이용하여 선미 보조동체 장착 유무에 따른 고속 Stepped Hull 선형의 횡동요 및 저항특성을 비교, 분석하였다.

• Journal of Chest Surgery
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• v.34 no.5
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• pp.403-406
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• 2001

본 증례는 66세(51.8kg)된 남자에서 수술전 심한 좌심실 기능 부전과 승모판 및 삼첨판 폐쇄부전이 있어 개심술 시행후 심한 저심박출증 발생으로 인공심폐기 이탈에서 실패하고 양심실 보조장치(Centrifugal Biopump)를 사용한 후 이로부터 성공적인 이탈과 퇴원이 보고하는 바이다.