• 지역사회간호학회지
• /
• 제30권3호
• /
• pp.307-323
• /
• 2019

Purpose: The purpose of this study is to analyze the contents of disaster nursing education at universities in Korea and Japan, with focus on textbooks. Methods: Disaster nursing contents from 11 Korean community health nursing textbooks and 3 Japanese disaster nursing textbooks were analysed. Results: Three themes and 8 categories of disaster nursing content in the selected textbooks were analyzed. The themes classified include 'understanding of disaster', 'disaster management' and 'disaster management system'. The theme of 'understanding of disaster' consists of such categories as 'disaster concept/outline', 'classification of disaster', 'disaster management step' and 'disaster impact'. The theme of 'disaster management activities' consists of categories such as 'disaster management activities' and 'disaster nursing'. The theme of 'national disaster management system' consists of categories like 'national disaster management system' and 'international disaster relief'. From the comparison of disaster nursing education in the two countries, we found that themes were similar but there were differences between the two countries in content configuration. Korea and Japan have adopted the framework of International Council of Nurses for disaster nursing education. Korea stressed legal and ethical capabilities, while Japan included psychological support for disaster management service providers. Conclusion: Disaster education is an important factor in a nurse's ability for a disaster management. Development of a comprehensive disaster education program is necessary to enhance disaster care capacities.

• Journal of Electrochemical Science and Technology
• /
• 제12권1호
• /
• pp.137-145
• /
• 2021

Among the non-precious metal catalysts, iron-nitrogen doped carbon (Fe-N/C) catalysts have been recognized as the most promising candidates for an alternative to Pt-based catalysts for the oxygen reduction reaction (ORR) under alkaline and acidic conditions. In this study, the nano replication method using mesoporous silica, which features tunable primary particle sizes and shape, is employed to prepare the mesoporous Fe-N/C catalysts with different shapes. Platelet SBA-15, irregular KIT-6, and spherical silica particle (SSP) were selected as a template to generate three different kinds of shapes of the mesoporous Fe-N/C catalyst. Physicochemical properties of mesoporous Fe-N/C catalysts are characterized by using small-angle X-ray diffraction, nitrogen adsorption-desorption isotherms, and scanning electron microscopy images. According to the electrochemical evaluation, there is no morphological preference of mesoporous Fe-N/C catalysts toward the ORR activity with half-cell configuration under alkaline electrolyte. By implementing X-ray photoelectron spectroscopy analysis of Fe and N atoms in the mesoporous Fe-N/C catalysts, it is possible to verify that the activity towards ORR highly depends on the portions of "Fe-N" species in the catalysts regardless of the shape of catalysts. It was suggested that active site distribution in the Fe-N/C is one important factor towards ORR activity.

• Journal of Astronomy and Space Sciences
• /
• 제37권4호
• /
• pp.237-247
• /
• 2020

The ground tracking support is a critical factor for the navigation performance of spacecraft orbiting around the Moon. Because of the tracking limit of antennas, only a small number of facilities can support lunar missions. Therefore, case studies for various ground tracking support conditions are needed for lunar missions on the stage of preliminary mission analysis. This study analyzes the ground supporting condition effect on orbit determination (OD) of Korea Pathfinder Lunar Orbiter (KPLO) in the lunar orbit. For the assumption of ground support conditions, daily tracking frequency, cut-off angle for low elevation, tracking measurement accuracy, and tracking failure situations were considered. Two antennas of deep space network (DSN) and Korea Deep Space Antenna (KDSA) are utilized for various tracking conditions configuration. For the investigation of the daily tracking frequency effect, three cases (full support, DSN 4 pass/day and KDSA 4 pass/day, and DSN 2 pass/day and KDSA 2 pass/day) are prepared. For the elevation cut-off angle effect, two situations, which are 5 deg and 10 deg, are assumed. Three cases (0%, 30%, and 50% of degradation) were considered for the tracking measurement accuracy effect. Three cases such as no missing, 1-day KDSA missing, and 2-day KDSA missing are assumed for tracking failure effect. For OD, a sequential estimation algorithm was used, and for the OD performance evaluation, position uncertainty, position differences between true and estimated orbits, and orbit overlap precision according to various ground supporting conditions were investigated. Orbit prediction accuracy variations due to ground tracking conditions were also demonstrated. This study provides a guideline for selecting ground tracking support levels and preparing a backup plan for the KPLO lunar mission phase.

• Structural Engineering and Mechanics
• /
• 제77권3호
• /
• pp.343-354
• /
• 2021

The frequencies formulas of the bridge are of great importance in the design process since these formulas provide insight dynamic characteristics of the structure, which guides the designers to parametric analyses and the layout of the bridge in conceptual or preliminary design. Continuous rigid frame bridge is popular in the mountainous area. Mostly, this type of bridge was simplified either as a girder or cantilever when calculating the frequency, however, studies showed that the different configuration of the bridge made the problem more complex, and there is no unified fundamental calculation pattern for this kind of bridge. In this study, an empirical frequency equation is proposed as a function of pier's height, stiffness of pier and the weight of the structure. A unified fundamental frequency formula is presented based on the energy principle, then the typical continuous rigid frame bridge is investigated by finite element method (FEM) to study the dynamic characteristics of the structure, and then several key parameters are investigated on the effect of structural frequency. These parameters include the number, position and stiffness of the tie beam. Nonlinear regression analyses are conducted with a comprehensive statistical study from plenty of engineering structures. Finally, the proposed frequency equation is validated by field test results. The results show that the fundamental frequency of the continuous rigid frame bridge increases more than 15% when the tie beams are set, and it increases with the stiffness ratio of tie beam to pier. The results also show that the presented unified fundamental frequency has an error of 4.6% compared with the measured results. The investigation can predicate the approximate longitudinal fundamental frequency of continuous ridged frame bridge, which can provide reference for the seismic response and dynamic impact factor design of the pier.

• 한국정보통신학회논문지
• /
• 제24권2호
• /
• pp.285-289
• /
• 2020

무선 네트워크의 계층적 구성은 다양한 네트워크 환경을 지원하기 위해 제공된다. 기지국에서는 두 가지 시스템 상태가 기본적으로 고려될 수 있으며, 이에 대해 액티브와 슬립 모드 사이에서 상태 전이가 발생할 수 있다. 그러므로 에너지 사용을 줄이기 위하여 저전력의 시스템 운영 관리가 기지국 시스템에 고려되어야 한다. 따라서 본 논문에서는 시스템 관리를 다루기 위해 Discontinuous Reception (DRX) 분석 모델을 고려한다. DRX 모델을 통하여 기지국 시스템의 운영에 대한 분석 방안을 제시하며 에너지 소비를 위한 저전력 강도를 살펴본다. 또한 시스템 상태에서 기지국의 저전력 소모에 대한 성능을 분석하기 위해 무선 자원 요구와 서비스 호 도착의 운영이 고려되며, 이를 위하여 유한 마르코프 시스템 모델을 사용하였다.

• 디지털융복합연구
• /
• 제19권11호
• /
• pp.63-73
• /
• 2021

스마트 도시를 실효성 있게 추진하기 위해서는 도시의 다양한 정보가 개방되고 연계되어야 하며, 각 구성원이 공유할 수 있는 체계가 필요하다. 또한 시민과 시민협의체의 참여가 가능한 협력체계의 구축이 필요하다. 이 연구에서는 시민참여를 가능하게 하는 스마트 도시를 만들기 위하여 스마트 도시 플랫폼의 구성요소와 개념모델을 제안하였다. 그 구성요소로는 실세계로부터 데이터를 수집하기 위한 센서, 정보 저장 및 관리, 정보공유 및 표준체계, 시민의 개인정보 보호 및 관리체계, 활용 및 서비스 등을 포함하고 있다. 개념모델에 대해서는 시민중심의 참여와 서비스가 이루어지도록 스마트 도시 구성원 간의 역할을 정의하였다. 또한 데이터의 수집, 정보연계 및 공유방안, 서비스 구성 체계 등에 대한 내용도 포함하고 있다. 시민은 데이터 수집 및 공급자, 서비스 기획가 또는 요구자, 서비스 수혜자 등의 다양한 역할을 수행할 수 있으며, 궁극적으로 시민들과의 자유로운 소통과 의견교환은 스마트 도시 성공의 핵심 요소라고 할 수 있다.

• Current Photovoltaic Research
• /
• 제10권2호
• /
• pp.33-38
• /
• 2022

Planner configuration thin film solar cells (TFSCs) with SnS/CdS heterojunction performed a lower short-circuit current (J_SC). In this study, we have demonstrated a path to overcome deficiency in J_SC by the incorporation of Se in the SnS absorber. We carried out the incorporation of Se in VTD grown SnS absorber by rapid thermal annealing (RTA). The diffusion of Se is mostly governed by RTA temperature (T_RTA), also it is observed that film structure changes from cube-like to plate-like structure with T_RTA. The maximum J_SC of 23.1 mA cm^-2 was observed for 400℃ with an open-circuit voltage (V_OC) of 0.140 V for the same temperature. The highest performance of 2.21% with J_SC of 18.6 mA cm^-2, V_OC of 0.290 V, and fill factor (FF) of 40.9% is observed for a T_RTA of 300℃. In the end, we compare the device performance of Se- incorporated SnS absorber with pristine SnS absorber material, increment in J_SC is approximately 80% while a loss in V_OC of about 20% has been observed.

• Structural Engineering and Mechanics
• /
• 제86권3호
• /
• pp.291-309
• /
• 2023

This paper addresses the finite element modeling of functionally graded porous (FGP) beams for free vibration and buckling behaviour cases. The formulated finite element is based on simple and efficient higher order shear deformation theory. The key feature of this formulation is that it deals with Euler-Bernoulli beam theory with only three unknowns without requiring any shear correction factor. In fact, the presented two-noded beam element has three degrees of freedom per node, and the discrete model guarantees the interelement continuity by using both C⁰ and C¹ continuities for the displacement field and its first derivative shape functions, respectively. The weak form of the governing equations is obtained from the Hamilton principle of FGP beams to generate the elementary stiffness, geometric, and mass matrices. By deploying the isoparametric coordinate system, the derived elementary matrices are computed using the Gauss quadrature rule. To overcome the shear-locking phenomenon, the reduced integration technique is used for the shear strain energy. Furthermore, the effect of porosity distribution patterns on the free vibration and buckling behaviours of porous functionally graded beams in various parameters is investigated. The obtained results extend and improve those predicted previously by alternative existing theories, in which significant parameters such as material distribution, geometrical configuration, boundary conditions, and porosity distributions are considered and discussed in detailed numerical comparisons. Determining the impacts of these parameters on natural frequencies and critical buckling loads play an essential role in the manufacturing process of such materials and their related mechanical modeling in aerospace, nuclear, civil, and other structures.

• 한국전산구조공학회논문집
• /
• 제36권2호
• /
• pp.121-130
• /
• 2023

기어의 구조 안정성 및 치물림 성능을 분석하기 위하여 유한요소해석이 널리 사용된다. 본 연구에서는 스퍼 기어의 유한요소 모델링 조건이 해석 결과 및 간소화 효과에 미치는 영향을 분석하였다. 기어 구조 해석의 간소화 방법으로 기어 몸체 및 잇수 간소화, 요소망 생성 방식, 접촉 및 마찰 조건, 해석 조건 등을 선정하였다. 기어의 성능해석 지표로써 1주기의 기어 치물림 사이클 동안의 정전달 오차를 계산하였고, 간소화 지표로써 해석 소요 시간을 측정하였다. 유한요소해석을 통해 치물림 주기에 따른 접촉 응력 분포 및 변화 양상을 확인하였다. 모델링 조건에 따라 최대 전달 오차와 해석 소요 시간에 차이를 확인하고 원인을 분석하였다.

• 한국조리학회지
• /
• 제22권4호
• /
• pp.240-253
• /
• 2016

본 연구는 외식전공 대학생의 외식산업분야 직업에 대한 인식을 파악하고, 응답자 특성에 따라 외식산업분야의 직업평가에 어떠한 차이를 보이는지 실증적으로 분석하였다. 연구의 목적을 달성하기 위하여 2014년 5월 19일부터 5월 30일까지 설문조사를 진행하여 211부를 SPSS 18.0을 이용하여 빈도분석, 탐색적 요인분석, 신뢰도분석, 상관관계분석, t-test, One way ANOVA를 시행하였다. 직업존중감에 대한 척도는 긍정적 가치, 사회적 평판, 부정적 대우, 상대적 효익으로 구성하였으며, 각 구성개념들은 통계적으로 유의한 타당성과 신뢰성을 확보하였다. 인구통계적 특성에 따른 직업존중감의 요인 별 차이를 분석한 결과, 성별에 따라 사회적 평판을 다르게 지각하고 있는 것을 확인하였고, 학년의 차이에 따라 긍정적 가치를 다르게 인식하고 있다는 것을 검증하였다. 또 전공에 따라 긍정적 가치와 부정적 대우에 대해 인지하는 정도가 다르다고 분석되었으며, 미래 희망직업에 따라 상대적 효익과 부정적 대우를 다르게 지각하고 있다는 것을 파악하였다. 이는 직업존중감이 높아지면 전공만족도와 진로결정수준이 높아진다는 선행연구의 결과에 따라 외식전공 대학생의 직업존중감을 높일 수 있는 방안을 모색해야 함을 시사하고 있다. 특히 외식산업분야 직업에 대해 가장 부정적으로 인식하고 있는 사회적 평판과 부정적 대우에 대한 보다 실질적인 개선책을 마련해야함을 강조하고자 한다.