• 한국항해항만학회지
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• 제46권4호
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• pp.338-343
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• 2022

글로벌 해운산업이 활성화됨에 따라 특정 국가들의 해양 영도를 경유하는 외국적 외항선의 규모가 급격하게 증가하였다. 하지만 선박의 컨디션 관리, 안전 운항을 위한 체계 수립이 미흡으로 선박 운항에 기인한 대형 해양사고가 발생하여 인명 피해와 심각한 해양환경오염을 유발하고 있다. 따라서 IMO는 해양 영토의 관할권을 갖는 국가들에게 항만국통제를 수행할 수 있는 권한을 부여하고 특히 외국적 선박에 대한 규정과 지침을 강화하였다. 특히 우리나라는 TOKYO MOU 회원국으로 항만국통제를 수행하고 있지만 2020년을 기준으로 국내를 기항한 국적선 대비 외국적선의 비중이 3배 높음에도 불구하고 9% 수준의 저조한 점검률로 TOKYO MOU에서 권고하고 있는 점검률 수준을 하회하고 있는 실정이다. 따라서 본 연구는 국내 항만국통제에 대한 효율성과 효과성을 개선하기 위한 목적으로 객관형 설문문항과 서면 전문가 인터뷰를 통해 항만국통제관들의 실무적 의견을 수렴하여 IPA분석과 컨텐츠분석을 수행하였다. 결과적으로 PSC점검의 질적 향상을 위해 수행 시 인적 요소와 관련된 선내 생활, 근무 환경, 안전사고 대응에 대한 중요성과 성과가 개선되어야 함이 도출되었다. 또한 PSC 점검성과 개선을 위해 유관 업무의 행정 일원화, 항만국통제관 인력 충원, 선박결함 신고제도 활성화, PSC 수행 그룹 재편성 등을 위한 다방면적 지원 기반이 마련된다면 우리나라 항만국통제에 대한 업무 환경과 성과가 개선될 것으로 판단된다.

• Transactions on Electrical and Electronic Materials
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• 제7권1호
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• pp.7-11
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• 2006

The changes of the electrical conductivity in chalcogenide amorphous semiconductors, $Ge_{1}Se_{1}Te_{2}$, have been studied. A phase change random access memory (PRAM) device without an access transistor is successfully fabricated with the $Ge_{1}Se_{1}Te_{2}$-phase-change resistor, which has much higher electrical resistivity than $Ge_{2}Sb_{2}Te_{5}$ and its electric resistivity can be varied by the factor of $10^5$ times, relating with the degree of crystallization. 100 nm thick $Ge_{1}Se_{1}Te_{2}$ thin film was formed by vacuum deposition at $1.5{\times}10^{-5}$ Torr. The static mode switching (DC test) is tested for the $100\;{\mu}m-sized$ $Ge_{1}Se_{1}Te_{2}$ PRAM device. In the first sweep, the amorphous $Ge_{1}Se_{1}Te_{2}$ thin film showed a high resistance state at low voltage region. However, when it reached to the threshold voltage, $V_{th}$, the electrical resistance of device was drastically reduced through the formation of an electrically conducting path. The pulsed mode switching of the $20{\mu}m-sized$ $Ge_{1}Se_{1}Te_{2}$ PRAM device showed that the reset of device was done with a 80 ns-8.6 V pulse and the set of device was done with a 200 ns-4.3 V pulse.

• Structural Engineering and Mechanics
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• 제49권5호
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• pp.645-660
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• 2014

This paper presents the design and project of an innovative concept for a Single Point Incremental Forming (SPIF) Machine. Nowadays, equipment currently available for conducting SPIF result mostly from the adaptation of conventional CNC machine tools that results in a limited range of applications in terms of materials and geometries. There is also a limited market supply of equipment dedicated to Incremental Sheet Forming (ISF), that are costly considering low batches, making it unattractive for industry. Other factors impairing a quicker spread of SPIF are large forming times and poor geometrical accuracy of parts. The following sections will depict the development of a new equipment, designed to overcome some of the limitations of machines currently used, allowing the development of a sounding basis for further studies on the particular features of this process. The equipment here described possesses six-degrees-of freedom for the tool, for the sake of improved flexibility in terms of achievable tool-paths and an extra stiffness provided by a parallel kinematics scheme. A brief state of the art about the existing SPIF machines is provided to support the project's guidelines.

• 대한화학회지
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• 제58권5호
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• pp.456-462
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• 2014

(+)-Camphorsulfonic acid (CSA)와 hydrochloric acid (HCl)로 binary 도핑된 키랄 polyaniline (PAni)을 중합온도 $0^{\circ}C$와 상온(RT)에서 전기화학적 중합법으로 합성하였다. 순환전압전류 곡선, FT-IR과 circular dichroism spectra로부터 PAni는 각각 (+)-CSA와 HCl로 single 도핑된 PAni 혼합물이 아닌, binary 도핑된 키랄 PAni임을 확인하였다. 중합온도가 전기화학적 거동과 도핑레벨에 영향을 주었고, 이에 따라서 PAni의 결정성과 모폴로지가 변화되는 것을 확인하였다. 중합온도가 $0^{\circ}C$에서 RT로 상승됨에 따라 키랄PAni의 모폴로지가 fibrous에서 short-fibrous구조로 변화되었다. ITO 위에 적층된 PAni필름의 면저항을 4-point probe 법으로 측정하였다.

• 한국전기전자재료학회논문지
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• 제27권11호
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• pp.736-739
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• 2014

In this paper, we propose a enhanced anti-corrosion property of the ground system by coating the CNT/PVDF composite film on it. Polymer material used for preventing the corrosion of ground system is polyvinylidene fluoride (PVDF), and conducting filler for obtaining conductivity of the composite film is multi-walled carbon nanotubes (MWCNTs). The MWCNTs were dispersed in the organic solvent of methyl ethyl ketone 2-butanone (MEK) with different concentration ratios, and the PVDF was solved in the MEK solvent with constant concentration ratio of 1 wt%. The CNT/PVDF composite solution was perpared by mixing and re-dispersing the CNT solution and the PVDF solution. Finally, the CNT/PVDF composite films were fabricated by the spray coating method using the above composite solution. Electrical conductivity, surface states, and anti-corrosion property of the CNT/PVDF composite films coated on the Cu substrate were evaluated. We found that the CNT/PVDF composite film showed relatively low resistance, hydrophobic surface state, and chemical stability. Consequently, we could improve the anti-corrosion property and maintain the electrical conductivity of the ground system by coating the CNT/PVDF composite film on it.

• International Journal of Contents
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• 제14권3호
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• pp.61-68
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• 2018

Unlike in the past, where the expression of the form was given a priority, with the widening of the scopes of the designs, the proportion of design education institution curricula targeting user experience and the application of technology is continually and gradually increasing. Open source microcontroller boards such as Arduino have initiated attracting attention as a countermeasure against these changes. These prototyping tools have many advantages for the diversification of expression and design verification in the design field and therefore have a high likelihood of being introduced into many design education institutes; however, the tools act as high entry barriers for design students who lack engineering knowledge. Although various educational content and tools have been developed to address the issue of barrier, existing solutions remain insufficient as alternatives for the purpose of activation. In this study, we investigated the present state of related education content and conducted a pilot workshop using a prototype microcontroller board with simplified coding. We intend to use the results of this investigation to develop study material for design education. We started by conducting a survey regarding the pre-university education situation. It was observed that engineering education opportunities are insufficient and the problem of mutual application between educations due to course-based education was not realized. We also analyzed the characteristics of simplified training tools using the microcontroller to establish a direction for educational design and conducted a pilot workshop using the microcontroller toolkit with a simplified coding process based on this content. Students who lack a basic knowledge of engineering technology received instruction, and after completing minimum preliminary training, they proceeded to practical exercises that involved utilizing the toolkit. Through this process, we identified the need for a simple-type microcontroller board with low-complexity for use in educating students majoring in design. We also identified some obstacles that serve as barriers to entry of utilizing microcontroller board. Based on these results, we propose several functional requirements and teaching guidelines for prototyping toolkits for design education.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.145-145
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• 2010

In this paper, we report that the effects of hydrogen doping on the electrical and optical properties of typical transparent conducting oxide films such as ZnO and $SnO_2$ prepared by magnetron sputtering. Recently, density functional theory (DFT) calculations have shown strong evidence that hydrogen acts as a source of n-type conductivity in ZnO. In this work, the beneficial effect of hydrogen incorporation on Ga-doped ZnO thin films was demonstrated. It was found that hydrogen doping results a noticeable improvement of the conductivity mainly due to the increases in carrier concentration. Extent of the improvement was found to be quite dependent on the deposition temperature. A low resistivity of $4.0{\times}10^{-4}\;{\Omega}{\cdot}cm$ was obtained for the film grown at $160^{\circ}C$ with $H_2$ 10% in sputtering gas. However, the beneficial effect of hydrogen doping was not observed for the films deposited at $270^{\circ}C$. Variations of the electrical transport properties upon vacuum annealing showed that the difference is attributed to the thermal stability of interstitial hydrogen atoms in the films. Theoretical calculations also suggested that hydrogen forms a shallow-donor state in $SnO_2$, even though no experimental determination has yet been performed. We prepared undoped $SnO_2$ thin films by RF magnetron sputtering under various hydrogen contents in sputtering ambient and then exposed them to H-plasma. Our results clearly showed that the hydrogen incorporation in $SnO_2$ leads to the increase in carrier concentration. Our experimental observation supports the fact that hydrogen acting as a shallow donor seems to be a general feature of the TCOs.

• 한국산학기술학회논문지
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• 제18권10호
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• pp.36-41
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• 2017

1991년 미국 오하이오 주립대학에서 처음 소개한 모바일 매핑 시스템은 센서기술이 발전함에 따라 다양한 형태로 개발되고 있다. 모바일 매핑 시스템은 이동체의 위치와 자세정보, 다양한 센서들의 취득 데이터를 통해 이동체 주변의 공간정보를 빠르게 취득할 수 있는 시스템으로 기존의 GNSS나 토털스테이션과 같은 측량 방법보다 생산성을 극대화 시키고 있다. 현재 해외 기업을 중심으로 다양한 시스템이 출시되고, 공간정보 구축분야에 적용이 활발하게 이루어지고 있지만 국내에서의 관련 기술개발이나 실질적 활용은 아직 부족한 실정이다. 본 연구에서는 지상기반 모바일 매핑 시스템을 중심으로 상용화된 시스템의 현황 조사 및 특징 분석을 수행하여 공간정보 관련 업무에 시스템 도입을 위한 기초자료를 제공하고자 하였다. 연구를 통해 다양한 형태의 모바일 매핑 시스템의 현황 및 특징을 파악하였으며, 최근 시스템 개발 동향이 도입단가를 낮추기 위한 방향으로 진행되고 있음을 제시하였다. 현재 자동 정합 등 자료처리 기술의 발달, 저가형 모델 출시 등 공간정보 구축 분야의 모바일 매핑 시스템 적용을 위한 기반이 조성되고 있어 향후 관련분야의 도입 활성화와 작업 효율성 향상이 기대된다.

• 동의신경정신과학회지
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• 제21권2호
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• pp.87-101
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• 2010

Objectives : The aim of this experiment was to investigate the influences of Autonomic Nervous System and EEG by conducting Reinforcement-Reduction(補瀉) acupuncture stimulation to compare the changes in acupoints on the body before and after treatment of acupuncture at Xingjian(LR2) being referred as Fire-point(火穴) and Ququan(LR8) being referred as Water-point(水穴) of Yin Liver Meridian(足厥陰肝經). Methods : This study was carried out on 30 healthy female volunteers in their 20's. There were four tests conducted throughout and the period for each test was between 2 to 5days. HRV and EEG were measured for 5 minutes before acupuncture stimulation was conducted on LR2-Reinforcement, LR2-Reduction, LR8-Reinforcement and LR8-Reduction at random. During the 20 minutes of acupuncture treatment, same subjects were measured simultaneously to observe any significant changes in acupoints. Again, the same subjects were measured for 5 minutes after removing the acupuncture in order to perform a comparative analysis. Results : The measurement of HRV showed that LF, LFnorm and LF/HF ratio increased significantly(p<0.05) while HF, HF norm decreased significantly in case of LR2-Reinforcement & LR8-Reduction. Both LR2-Reduction and LR8-Reinforcement induced a significant increase in HFnorm. EEG measurement indicated low $\alpha$ wave decreased and high $\beta$ wave increased significantly at LR2-Reinforcement during post-acupuncture period compared with acupuncture stimulation period. Both LR2-Reduction and LR8-Reinforcement developed significantly low $\alpha$ wave and high $\alpha$ wave. High $\beta$ wave increased significantly at LR8-Reduction during the acupuncture stimulation in comparison with pre-acupuncture period. Conclusions : The manipulation of acupuncture stimulation at LR2-Reinforcement and LR8-Reduction enhanced the activity of sympathetic nerves and the state of arousal while that of para sympathetic nerves declined. On the other hand, LR2-Reduction and LR8-Reinforcement developed the levels of para sympathetic nerves and relaxation.

• 농촌의학ㆍ지역보건
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• 제48권1호
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• pp.41-49
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• 2023

2022년 11월부터 2023년 2월까지 동국대학교 경주병원 이비인후과 외래를 내원한 환자 중에서 소음성 난청을 가진 어선원의 의무기록을 후향적으로 검토하여 소음성 난청을 가진 총 10명의 19개 귀의 청각학적 특성을 분석하였다. 모두 60세 이상의 남자였고 소음에 노출된 기간은 평균적으로 38.9 ± 10.8년으로 장기간 소음에 노출되었으나 난청기간은 평균적으로 13.4 ± 4.3년으로 소음노출에 비해서 늦게 난청을 인지하였다. 고음역 평균역치가 저음역 평균역치보다 높지만, 8 kHz에서 하강하는 청력도를 보였고 고음역 평균 청력역치가 75 dB 초과인 경우는 10.5%이나 저음역 평균 청력역치가 40 dB 초과인 경우가 57.9%를 차지하였다. 순음청력검사상 평균 청력역치는 52.2 ± 7.1 dB, 어음청취역치는 34.0 ± 11.1 dB, 어음명료도검사는 81.5 ± 11.4%, 청성뇌간반응검사의 청력역치는 56.8 ± 6.7 dB, 청성지속반응검사의 청력역치는 63.7 ± 7.6 dB였다. 향후 다기관 연구에서는 어선의 소음의 크기 및 근로시간 등 근로환경에 대한 조사를 같이 시행하여 소음노출을 확인 후 어선원 소음성 난청 청각학적 특성을 분석해야 할 것이다.