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        검색결과 261

        1.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        곧 다가올 미래에는 자율운항선박, 육상 원격제어센터에서 제어되는 선박, 그리고 항해사가 탑승하여 운항하는 선박이 함 께 공존하며 해상을 운항할 것이며, 이러한 상황이 도래했을 때 해상 교통 환경의 안전을 평가할 수 있는 방법이 필요할 것으로 사료 된다. 이에 본 연구에서는 자율운항기술을 사용하여 항해사가 직접 조종하는 선박과 자율운항선박이 공존하는 해상환경 하에서 선박 조종시뮬레이션을 통해 통항 안전성을 평가하기 위한 방안을 제시하였다. 자선은 6-자유도 운동 기반의 MMG 모델을 심층 강화학습 기법 중 하나인 PPO 알고리즘으로 학습하여 자율운항 기능을 갖출 수 있도록 설계하였다. 타선은 평가 대상 해역의 해상 교통 모델 링 자료로부터 선박이 생성되도록 하였고, 기 학습된 선박모델을 기반으로 자율운항 기능을 구현되도록 하였다. 그리고 해양기상 자 료 데이터베이스로부터 조위, 파랑, 조류, 바람에 대한 자료를 수집하여 수치 모델을 수립하고 이를 기반으로 해양기상 모델을 생성하 여 시뮬레이터 상에서 해양 기상이 재현되도록 설계하였다. 마지막으로 안전성 평가는 기존의 평가 방법을 그대로 유지하되, 선박조 종시뮬레이션에서 해상교통류 시뮬레이션을 통한 충돌 위험성 평가가 가능하도록 하는 시스템을 제안하였다.
        4,000원
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to develop virtual reality (VR)-based content on surgical aseptic techniques for nursing students and evaluate its effectiveness. Methods: The content was developed following the system development life cycle, involving analysis, design, implementation, and evaluation. Experts and fourth-year nursing students validated the content for its validity and usability of the content. The study was conducted from December 2022 to April 2023. Results: The VR content was developed using Keller's ARCS motivational design model (attention, relevance, confidence, and satisfaction) as the fundamental strategy. Upon applying the VR content developed in this study, the research participants confirmed the values of the following sub-factors: confidence (3.86 out of 5), relevance (3.74 out of 5), attention (3.68 out of 5), and satisfaction (3.65 out of 5). Conclusion: VR-based surgical content on aseptic techniques demonstrates potential benefits for nursing students. Therefore, through systematic development and utilizing of diverse nursing skill content, we can enhance the core competencies of nursing students, providing them with high-quality practical education.
        4,800원
        3.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to develop virtual reality (VR)-based content on surgical aseptic techniques for nursing students and evaluate its effectiveness. Methods: The content was developed following the system development life cycle, involving analysis, design, implementation, and evaluation. Experts and fourth-year nursing students validated the content for its validity and usability of the content. The study was conducted from December 2022 to April 2023. Results: The VR content was developed using Keller's ARCS motivational design model (attention, relevance, confidence, and satisfaction) as the fundamental strategy. Upon applying the VR content developed in this study, the research participants confirmed the values of the following sub-factors: confidence (3.86 out of 5), relevance (3.74 out of 5), attention (3.68 out of 5), and satisfaction (3.65 out of 5). Conclusion: VR-based surgical content on aseptic techniques demonstrates potential benefits for nursing students. Therefore, through systematic development and utilizing of diverse nursing skill content, we can enhance the core competencies of nursing students, providing them with high-quality practical education.
        4,800원
        6.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The increase in particulate matter due to increased air pollutant emissions has become a significant social issue. According to the Ministry of Environment, air pollutants emitted from large-scale businesses in 2022 increased by 12.2% compared to the previous year, indicating that air pollution is accelerating owing to excessive industrialization. In this study, TiO2, which is used to reduce airborne particulate, was used. The TiO2 coating fixation and dynamic pressure coating-type TiO2 fixation methods were used to solve the material peeling phenomenon caused by gravity, which is a limitation when the TiO2 penetration method is applied to a vertical concrete structure along the road. The long-term durability and performance were analyzed through environmental resistance and NOx removal efficiency evaluation experiments. These analyses were then assessed by comparing the NOx removal efficiency with the dynamic pressure permeationtype TiO2 fixation method used in previous studies. METHODS : To evaluate the long-term durability and performance of the TiO2 coating fixation method and dynamic pressure coating TiO2 fixation method for vertical concrete structures, specimens were manufactured based on roadside vertical concrete structures. Environmental resistance tests such as the surface peeling resistance test (ASTM C 672) and freeze-thaw resistance test (KS F 2456) were conducted to evaluate the long-term durability. To evaluate the long-term performance, the NOx removal efficiency of TiO2 concrete owing to road surface deterioration during the environmental resistance test was evaluated using the NOx removal efficiency evaluation equipment based on the ISO 22197-1 standard. This evaluation was compared and analyzed using the dynamic pressure infiltration TiO2 fixation method. RESULTS : The long-term durability of the TiO2 coating fixation and dynamic pressure coating TiO2 fixation methods were evaluated using environmental resistance tests. During the surface peeling resistance test, the TiO2 material degraded and partially detached from the concrete. However, the NOx removal efficiency was ensured by the non-deteriorated and fixed TiO2 material. The long-term performance was confirmed through a freeze-thaw resistance test to evaluate the NOx removal efficiency after 300 cycles of surface deterioration. The results showed that when the TiO2 coating fixation and dynamic pressure infiltration TiO2 fixation methods were applied to vertical concrete structures, the durability of the structure was not compromised. In comparison to the dynamic pressure infiltration TiO2 fixation method, the NOx removal efficiency observed during the surface peeling resistance test was lower, while the freeze-thaw test exhibited notably higher removal efficiency. CONCLUSIONS : To solve the material peeling phenomenon caused by gravity, the long-term durability and performance were evaluated by applying the TiO2 coating fixation and dynamic pressurized coating TiO2 fixation methods to vertical concrete specimens. Long-term durability was confirmed through environmental resistance tests, and long-term utility was secured by measuring the NOx removal efficiency according to surface degradation. These findings show that implementing the TiO2 coating fixation method and dynamic pressure coating TiO2 fixation methods on-site effectively reduce NOx.
        4,600원
        8.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, non-destructive technologies that can be applied to evaluate the integrity of valve materials, safety against internal pressure caused by corrosion, and the blocking function of large-diameter water valves during operation without requiring specimen collection or manpower entering the inside of the valve were tested to assess the reliability of the technologies and their suitability for field application. The results showed that the condition of the graphite structure inside the valve body can be evaluated directly through the optical microscope in the field without specimen collection for large-diameter water butterfly valves, and the depth of corrosion inside the valve body can be determined by array ultrasound and the tensile strength can be measured by instrumented indentation test. The reliability of each of these non-destructive techniques is high, and they can be widely used to evaluate the condition of steel or cast iron pipes that are significantly smaller in thickness than valves. Evaluation of blocking function of the valves with mixed gas showed that it can be detected even when a very low flow rate of mixed gas passes through the disk along with the water flow. Finally, as a result of evaluating the field applicability of non-destructive technologies for three old butterfly valves installed in the US industrial water pipeline, it was found that it is possible to check the material and determine the suitability of large-diameter water valves without taking samples, and to determine the corrosion state and mechanical strength. In addition, it was possible to evaluate safety through the measurement results, and it is judged that the evaluation of the blocking function using mixed gas will help strengthen preventive response in the event of an accident.
        4,800원
        9.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        신기술에 대한 투자규모가 크게 증가하고 있고, 과학기술이 사회 전반적으로 대규모·복합적인 영향을 미치고 있다. 정부는 새로운 신기술이 사회에 수용되려면 과학기술에 대한 국민적 관심이 큰 만큼 기술이 국민과 사회에 미치는 영향에 대해서 잘 평가할 의무가 있다. 이를 위한 사회적 합의를 이루기 위해 기술영향평가를 한다. 이를 위한 방법에 대한 연구가 50년째 지속되고 있고, 다양한 학술연구와 수많은 신기술 대응 정책을 통해 논의 된 이후 시대적 변화와 흐름이 있었기에 글로벌 학계와 정책에서 신기술의 미래사회 영향력에 대한 다각적 분석 등이 강조되고 있다. 본 연구는 선진국의 기술영향평가 창안 방식과 우리나라에서 발전된 방식이 다름에도 불구 하고 그동안 신기술 기술영향평가 고려되어야 하는 예측요소와 단계 등 연구 변화에 주목하였다. 연구결과 인식도에 대해 기술 이해도, 전문성, 성별특성 세 개 요소를 도출하고, 기존 요소에 추가해 신기술 예측요소로 제안하였다. 연구의 결과는 우리나라 과학기술기본법에 의거 개선된 기술영향평가를 실시하는데 있어 학술 및 정책적 뒷받침하는 근거를 제시하였다.
        9,300원
        10.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        해양산업시설의 위험유해물질 배출이 미치는 사회영향을 평가하고, 기술근거배출허용기준 설정과정에서 요구되는 사회영향평 가 항목 및 방법적용에 대한 시사점을 도출하였다. 연구범위는 인천광역시에 있는 해양산업시설을 대상으로 하였다. 분석결과는 다음과 같다. 첫째, 기업 및 산업에 대한 영향은 ‘큰’ 것으로 평가되었지만, 대기업은 영업이익손실과 도산가능성, 그리고 고용손실의 영향이 적 었고, 소기업과 중기업은 영향이 큰 것으로 나타났다. 둘째, 지역사회 및 경제에 대한 영향은 ‘적은’ 것으로 평가되었으나, 직접적으로 인 과관계를 지니는 어업생산자나 지역관광종사자, 그리고 해당 지역은 그 영향이 집중되어 크게 나타날 수 있기 때문에 이에 대한 세심한 정책적 개입이 필요한 것으로 판단된다. 셋째, 기술근거배출허용기준의 설정방법에서 사회적 손실비용 및 사회적 편익산정 항목과 방법 이 유용하게 적용될 수 있는 것으로 판단된다.
        4,300원
        12.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Advancements in science and technology caused by industrialization have led to an increase in particulate matter emissions and, consequently, severity of air pollution. Nitrogen oxide (NOx), which accounts for 58% of road transport pollutants, adversely affects both human health and the environment. A test-bed was constructed to determine NOx removal efficiency at the roadside. TiO2, a material used to reduce particulate matter, was used to remove NOx. It was applied to a vertical concrete structure using the dynamic pressurized penetration TiO2 fixation method, which can be easily applied to vertical concrete structures. This study was conducted to evaluate the NOx removal efficiency of the dynamic pressurized-penetration TiO2 fixation method in a test-bed under real roadside conditions. METHODS : A test-bed was constructed in order to determine the NOx removal efficiency using the dynamic pressurized penetration TiO2 fixation method on the roadside. The dynamic pressurized-penetration TiO2 fixation method was applied by installing a vertical concrete structure. NOx was injected into the test-bed using an exhaust gas generator. By installing a shading screen, the photocatalytic reaction of TiO2 was suppressed to a maximum concentration of 1000 ppb along the roadside. The removal efficiency was evaluated by measuring NOx concentrations. In addition, illuminance was measured using an illuminance meter. RESULTS : From the results of the analysis of the NOx removal efficiency in the test-bed which the dynamic pressurized type TiO2 fixation method was applied to, an average removal efficiency ranging from 18% to 40% was achieved, depending on the illuminance. Similarly, according to the results of the evaluation of the NO removal efficiency, an average of removal efficiency ranging from 20% to 62% was achieved. Thus, the NOx removal efficiency increased when the illuminance was high. CONCLUSIONS : From the results of the experiment conducted, the efficiency of NOx removal per unit volume was obtained according to the illuminance of TiO2 concrete along an actual road. Field applicability of the dynamic pressurized-penetration-type TiO2 fixation method to vertical concrete structures along roads was confirmed.
        4,000원
        14.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, as the proportion of aged pipelines increases rapidly, in the event of an accident caused by corrosion and structural deterioration of metal pipes, appropriate overlay welding is applied in the field to partially repair it. The size of the base steel plate and the selection of a stable welding method were evaluated, and possible problems caused by the overlay welding were identified, and improvement measures were proposed. For the test, a new steel pipe coated with epoxy lining on the inner surface and polyethylene on the outer surface was subjected to a tensile test by processing the repaired specimen through overlay welding with a steel plate after artificial cracking, and structural safety was evaluated after repair. Furthermore, the influences of the size of the throat and the size of the steel plate were analyzed. As a result of the tensile test by dividing the repaired steel plate overlay into a constraint and non-constraint conditions, the tensile load was concentrated in the welded part and damage occurred in the welded part. It was found that the maximum load leading to breakage increases as the size of the welding throat increases. In addition, it was found that the resistance to load increased slightly as the size of the overlaid steel plate increased, but the effect was not significant, confirming the need for repair in consideration of the site conditions. As a result of evaluating the damage to the coating material on the back side of the welding, it was confirmed that the coating material on the opposite side of the welding burned black(epoxy) or was greatly deformed by heat(polyethylene). Therefore, it is necessary to secure structural stability through repainting, etc. in order to prevent damage to the coating material on the opposite side during overlay welding.
        4,300원
        15.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 토목공학 분야 내 현장조건을 구현할 수 있는 스마트 건설 기술의 요소기술로서 3D 프린팅 기술의 적용 분야 가 확대되고 있다. 센서기술의 보조도구, 모듈러 시공상 적용 등으로 다양하게 활용되고 있는 가운데 3D 프린팅 기술을 단순 부재 제작이 아닌 각각의 부재들이 최대 성능을 발휘할 수 있는 최적설계 도출 방안으로 활용하고자 한다. 이를 위해 3D 프린 팅 재질인 필라멘트를 활용하더라도 신뢰성 있는 최적설계가 도출이 가능한지에 대한 연구가 선행되어야 하며, 이에 본 연구에 서는 지반보강재 중 하나인 지오셀 관련 선행연구 결과와 필라멘트의 물성치가 적용된 해석 결과와의 비교를 통해 재료적 신뢰 성을 검증하고자 한다. 해석 결과, 지오셀 구성요소에 따른 보강성능의 경향이 기존 선행연구 결과와 일치함을 확인하였기에 필 라멘트를 활용하더라고 충분히 신뢰성 있는 최적설계가 도출이 가능할 것이라 판단된다.
        4,000원
        16.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 프리팹 구조물의 품질관리를 위한 딥러닝 및 비전센서 기반의 조립 성능 평가 모델을 개발하였다. 조립부 검출을 위 해 인코더-디코더 형식의 네트워크와 수용 영역 블록 합성곱 모듈을 적용한 딥러닝 모델을 사용하였다. 검출된 조립부 영역 내의 볼트 홀을 검출하고, 볼트홀의 위치 값을 산정하여 k-근접 이웃 기반 모델을 사용하여 조립 품질을 평가하였다. 제안된 기법의 성능을 검증 하기 위해 조립부 모형을 3D 프린팅을 이용하여 제작하여 조립부 검출 및 조립 성능 예측 모델의 성능을 검증하였다. 성능 검증 결과 높은 정밀도로 조립부를 검출하였으며, 검출된 조립부내의 볼트홀의 위치를 바탕으로 프리팹 구조물의 조립 성능을 5% 이하의 판별 오차로 평가할 수 있음을 확인하였다.
        4,000원
        19.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : High concentrations of particulate matter (PM) are emitted or generated from vehicle emissions in urban roads with dense transient populations. To reduce the effect of PM emission on bus stop users at roadsides, a plan to reduce PM emitted from the roadside must be devised. In this study, an atmospheric environment at a roadside is simulated in a large-scale environment chamber, and a test for reducing PM around the bus stop is conducted by installing a bus stop adapted to a PM reduction system. METHODS : Exhaust gas is injected into the experimental and reference chambers using diesel and gasoline vehicles for roadside airquality simulations. The two vehicles are operated in an idle state without an acceleration operation to emit exhaust gas uniformly, and the initial conditions are achieved by injecting car emissions for approximately 40 min. The initial condition is set to 1 ppm of NOx concentration in the environment chamber. Between the two environment chambers, a bus stop adapted to the PM reduction system is installed in the experimental chamber to conduct a PM reduction experiment pertaining to the air quality around the roadside. The experimental progress is set as the start time of the experiment based on the time at which the initial conditions are achieved; simultaneously, the PM reduction system in the experimental chamber is operated. After the simulation is commenced, the PM concentration, which changes over time, is measured using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) without additional injection of car emissions or pollutants. The HR-ToF-AMS measures the chemical composition of non-refractory PM1.0 (NR-PM1.0) in real time. RESULTS : The NR-PM1.0 compound (organic aerosol (OA), NO3 -, SO4 2-) increases by 160% compared with the simulated initial concentration up to T90min in both environmental chambers; this is speculated to be due to secondary formation. The reference chamber indicates a slight decrease or a steady-state after T90min, whereas the experimental chamber indicates a gradually decrease as the experiment progresses. The bus stop adapted to the PM reduction system reduces the amount of black carbon in the experimental chamber by 37% at 200 min. This implies that the PM emitted from the roadside is filtered via the PM reduction system installed at the bus stop, and cleaner air quality can be provided to passengers. CONCLUSIONS : The PM reduction system evaluated in this study can be detached from and attached to the outdoor billboard of a bus stop. Since it adopts air filtration technology that uses a high-efficiency particulate air filter, it can be maintained and managed easily. In addition, it can provide an atmospheric environment with reduced PM emission to passengers as well as provide a better air-quality condition to passengers waiting for public transportation near roadsides.
        4,000원
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