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        검색결과 412

        1.
        2024.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        해외 위험지역에서 다양한 위난상황으로부터 재외국민을 보호하고 본 국으로 안전한 귀환을 위해 외교·국방·정보 역량을 동원하여 수행되는 활 동이 비전투원후송작전(NEO)이다. 미국과 한국이 수행했던 NEO 사례분 석을 바탕으로 도출된 NEO의 성공적인 수행을 위한 요인과 시사점은 다 음과 같다. 첫째, NEO 계획의 핵심요소는 변화하는 작전환경에 대한 상 황인식과 대비태세이다. 둘째, 후송작전의 기본원칙인 정확성, 보안, 속 도를 기반으로 하여 적대세력의 접근경로와 공격유형을 파악하고, 급변 하는 위협환경에 대응할 수 있는 신속대응군과 후송부대를 투입해야한 다. 셋째, NEO 계획, 경보발령, 집결·재배치, 후송·귀환 과정에서 국무부 /외교부, 국방부, 재외공관, NEO 수행부대 간의 효과적인 협력과 조정 업무가 이루어져야한다. 넷째, 국방부와 정보기관은 현지 임무수행단에 게 작전지역 평가, 위협평가, 적대세력의 위협방책 식별, 대응책 등의 정보를 제공해야한다. 다섯째, 내란과 분쟁지역에서 NEO는 시·공간 제 한사항이 많은 원거리 해외지역에서 작전이기 때문에 동맹국·우방국과의 긴밀한 군사협력 및 연합작전도 필수적이다.
        7,000원
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, the resources and energy consumed to produce hot mix asphalt mixtures and hot mix reclaimed asphalt mixtures in asphalt concrete plants were estimated and the emissions from the detailed processes of the production process were evaluated based on TRACI(the tool for the reduction and assessment of chemical and other environmental impacts). METHODS : To estimate the energy consumption of the aggregate drying process, which consumes a significant amount of energy in the production process, an energy consumption calculation model based on the thermal equilibrium equation was used, and the energy consumed for material transportation, storage, and operation of other facilities was cited from the literature. RESULTS : For the system boundary conditions established and the inventory considered, the emissions to produce one ton of hot mix reclaimed asphalt mix are greater than the emissions to produce one ton of hot mix asphalt mix for a number of key impact categories. The process of producing hot mix reclaimed asphalt mixtures was evaluated to consume more resources and energy in the production of recycled aggregates and heating for drying than in the production of hot mix asphalt mixtures, but less resources and energy in the production of binders and natural virgin aggregates and the heating to heat these materials. CONCLUSIONS : The results of the emissions assessment using the life cycle inventory for the production of hot mix asphalt mixtures were generally similar to the results understood in the field and in much of the literatures, confirming the reliability of the methodology. However, in order to evaluate the dominance of specific processes or mixtures, it is believed that the construction of a wide range of inventory databases after inventory redesign is necessary for a specific and rigorous assessment.
        4,000원
        7.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, energy-consuming processes in asphalt plants were evaluated, and the drying and mixing processes were characterized using a thermal equilibrium equation-based model to quantitatively estimate the amount of energy consumed during the production of mixtures in asphalt concrete plants. METHODS : An energy consumption model based on the thermal equilibrium equation was used to estimate the energy consumption of the aggregate drying process that consumes the maximum energy; the energy consumed for material transportation, storage, and operation of other facilities was cited from the literature. The results were compared with the actual results obtained for recycled hot asphalt mixtures and recycled warm mix asphalt mixtures, and a sensitivity analysis was performed by varying the conditions. RESULTS : An analysis of the main processes required to produce asphalt mixtures showed that the water content had the largest impact on energy consumption (approximately 80%). This quantitatively supports the opinion of field practitioners that maximum energy is consumed during aggregate drying. Although some discrepancies were observed, the results were found to be reasonable and within the range of typical measurements. CONCLUSIONS : The thermal energy consumption estimation model provides consistent results that reflect the characteristics of the mixture and can be used to derive the thermal energy consumption rates for individual materials, such as aggregates and binders. This can be used to identify the priorities for process optimization within a plant.
        4,000원
        8.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to determine whether machine learning techniques based on the results of chemical analysis experiments can be rationally applied to evaluate the aging of various asphalt binders used throughout the country. METHODS : We conducted chemical experiments such as FT-IR, H-NMR, C- NMR, and GPC for the three-stage aging levels of eight types of asphalt binders used in the country and utilized two artificial neural network models to determine valid chemical experimentation and conditions for the use of neural modeling through predictions. RESULTS : The M-prop model, which combined the findings from each neural network model into a single artificial neural network model, demonstrated superior predictive performance compared with the M-base model, which assessed aging using two cluster layers. In addition, the minimum amount of data required to achieve 100% predictive accuracy for the target asphalt binders, regardless of the artificial neural network model, was 18, and the amount of training data decreased to less than 50%. CONCLUSIONS : The predictive accuracy of the aging of asphalt binders was significantly enhanced when GPC data was used, indicating that GPC should be prioritized in evaluating the aging of asphalt binders.
        4,000원
        11.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, we aimed to evaluate the transition temperature (Tt) of asphalt binders using molecular dynamics simulations, which can provide a more accurate assessment of the mechanical properties of a material at the molecular level and can be applied to material development and design. METHODS : Unlike conventional macro- or meso-level simulations, we utilized MD simulations to evaluate the Tg of asphalt binders based on material composition and aging degree as input variables. In this analysis, 11 temperatures ranging from 434 K to 233 K at 20 K intervals were utilized, and the bulk volume and density were calculated through MD simulations. RESULTS : The MD simulation successfully predicted the Tg of the asphalt binder, and the molecular-level properties and interactions determined in this study can be applied not only to material development but also to the determination of constitutive equations or contact models used in continuum mechanics or discrete element methods. The calculated Tg was slightly different depending on the aging of the asphalt binder; however, it was found to accurately reflect the transitional characteristics. CONCLUSIONS : This study demonstrated the potential of MD simulations as valuable tools for material development and design in the construction industry. The results indicate that the use of MD simulations can lead to more accurate and efficient material development and design by providing a more detailed understanding of material properties and interactions at the molecular level.
        4,000원
        15.
        2022.12 구독 인증기관 무료, 개인회원 유료
        목적 : 국내·외에서 보고된 뇌졸중 환자 대상의 운전 시뮬레이터 훈련 연구의 체계적 고찰을 통해 연구 경향과 대상자 특성, 사용 방법 및 시뮬레이터를 통한 중재의 효과성에 대해 알아보고자 한다. 연구방법 : RISS, PubMed 등의 데이터베이스를 이용하여 선정 기준에 부합하는 5편의 국내·외 연구를 검색하였 다. 분석 대상 연구들은 연구의 근거 기반 질적 수준 분석 모델에 따라 분류하였고, 임상적 분석 방법인 P.I.C.O 방법에 따라 분석하여 정리하였다. 결과 : 고찰한 연구는 총 5개로 근거 수준은 I, IV였다. 연구 대상자는 뇌졸중 환자로 운전 시뮬레이터 훈련 중재 를 통해 운전 기능 향상의 효과를 살펴보았으며, 중재 결과 다양한 영역에서의 향상이 보고되었음을 확인할 수 있었고, 1편의 논문을 제외한 4편의 논문에서 운전 기능의 유의미한 향상을 보고하였다. 결론 : 시뮬레이터를 이용한 중재는 많은 연구를 통해 효과가 입증되고 있었다. 추후 연구 대상자를 더욱 다양하 게 하여 도로 주행 능력 및 다양한 영역에서의 기능 향상을 위한 운전재활 연구가 지속적으로 이루어져야 할 것이다.
        4,200원
        16.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, emissions from asphalt mixture production and construction processes are calculated and used to estimate the emission from each asphalt pavement layer. The calculated emissions for the processes are used as fundamental data to estimate the total emission from the entire life cycle of pavement engineering in South Korea. METHODS : A design proposal and the Korean standard, which provide quantitative information for activities, were used to estimate the amount of construction materials and energy consumption. Subsequently, the LCI DB from NAPA and the LCIA DB from EPA were utilized in conjunction with the estimated quantity to assess the effect of the emissions to determine their environmental impact categories. RESULTS : Calculation results show that 5.84 million ton of CO2eq is discharged from production and construction processes, whereas 3.24 million ton of CO2eq is discharged from operation processes in the pavement engineering sector. The total GHG emission, i.e., 9.08 million ton of CO2eq, is approximately 1.25% of the national GHG emission in 2018. The asphalt mixture production process results in the highest GHG emission in the life cycle of asphalt pavements. CONCLUSIONS : An LCI DB that accounts for the industrial characteristics of South Korea must be established to provide more reliable emission data to be used for national GHG reduction plans, including those for the pavement engineering sector.
        4,000원
        19.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 민선8기 지방선거에서 충청북도 도시자 후보자 토론 의제 선정 과정을 중심으로 하여 지방선거의 정책의제를 분석한다. 이를 위해 지방선거 과정에서 광역단체장인 충북 도시자 후보자 토론의제 선정 과 정 속에서 전문가 집단을 대상으로 하는 쟁점 정책의제의 도출을 위한 내용분석과 도출된 정책의제에 대한 우선순위 분석을 실시한다. 분석방 법으로는 전문가 집단을 대상으로 한 개방형 질문에 대한 답변에 대한 내용분석을 통해 분야별 쟁점 정책의제를 도출하고, 도출된 정책의제를 대상으로 AHP 분석기법을 활용하여 우선순위를 도출한다. 이를 통해 이 연구는 지방선거 과정에서의 정책방향과 경향성에 대한 논의의 중요한 근거자료를 제공하고, 이에 더해 도출된 정책의제에 대한 우선순위 분석 을 통해 지역 내에서 우선적으로 다루어질 필요가 있는 핵심 정책의제에 대한 유용한 자료를 제공한다는 의의를 갖는다.
        6,400원
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