• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.5
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• pp.44-51
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• 2022

In this study, 5-axis machining was proposed as a method for manufacturing a nozzle with a curved shape, and flow analysis and structural analysis were used for structural validation of the manufactured geometry. The program used for CFD obtained the internal temperature and pressure distribution of the nozzle using STAR-CCM+ and used it as the boundary condition for structural analysis. For structural analysis, the commercial program NASTRAN was used, and stress was calculated using the von-mises technique. Based on the maximum stress value generated, the safety margin was 0.78 and the safety margin of the bearing stress was 46.8. In addition, the creep life was calculated as 9.97 x 1012 hours using the Larson-Miller parametric method and applying the maximum stress value of 187 MPa and the exhaust gas perfectly mixed temperature of 463 K.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.479-479
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• 2021

최근 기상이변으로 인한 자연재해 발생이 증가하고 있고, 그에 따라 도시의 재난 대응력 강화가 국내에서는 물론 국제적으로도 중요한 이슈가 되고 있다. 특히 쇠퇴지역은 재난재해 발생 시 인적·물적 피해가 일반 지역 보다 상대적으로 크며, 복구에도 많은 시간과 예산이 소요되므로 대응책 마련을 위한 도시재생지역의 정밀한 재난재해의 위험성 분석 기술이 필요하다. 이에 본 연구에서는 도시재생사업 대상지(311개)에 대한 재난재해 유형별 위험성 및 회복성을 종합적으로 분석하는 종합진단 기법을 개발하고, 이를 적용한 프로토타입 시스템을 개발하였다. 재난재해의 범위는 「재난 및 안전관리 기본법」을 준용하여 이에 도시재생사업 시행에 영향을 받아 재난재해 발생에 따른 위험정도가 변화할 가능성이 높은 자연재해 (폭우, 폭염, 폭설, 강풍, 지진)5종과 사회재난 (화재, 붕괴, 폭발) 3종 총 8종으로 정의하였다. 종합진단 기법은 기후변화에 관한 정부간 협의체(IPCC) 위험도 평가 방법을 준용하여 위험요소 (위해성·취약성·노출성)와 대비·대응요소 (회복성)로 구분하고, 전문가 자문회의를 거쳐 재난재해에 특히 취약한 쇠퇴지역의 특성을 반영할 수 있는 종합진단지수 산정식을 개발하였다. 또한 쇠퇴지역 재난재해 종합진단 시스템은 도시재생 업무를 수행하는 사용자가 신속히 정보를 분석하고 활용에 용이하도록 Web-GIS 기반으로 설계하였으며, 종합진단 기법에 의해 산정된 분석결과를 100m × 100m 격자 단위의 등급으로 가시화한다. 분석 결과는 지속적인 연구 개발을 통해 최적의 도시재생사업 의사결정 지원 서비스를 위한 기초 분석 자료로 연계하여 활용되며, 분석 DB는 클라우드 서비스 기반의 도시재생 데이터 플랫폼을 통해 공유된다.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.707-715
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• 2023

This study utilized CART algorithm, a decision tree analysis method, to comparatively analyze factors affecting housing and residential environment satisfaction by region using data from Ministry of Land, Infrastructure and Transport's housing survey in 2020. First, in terms of residential environment satisfaction, accessibility to medical facilities and school district showed higher importance in metropolitan cities and areas compared to other regions, whereas safety from accident showed the opposite trait, showing difference between region. Second, housing characteristics were important in housing satisfaction, indoor environment level satisfaction and indoor safety and hygiene being important in almost all regions, while residential environment characteristics were more important in residential environment satisfaction and influencing factors were relatively evenly distributed. In order to generalize these regional characteristics, research using time series data needs to be conducted later.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.1
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• pp.273-286
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• 2022

An HD map is essential in the automated driving of level 4 and above to generate the vehicle's global path since it contains road information and each road's lane information. Therefore, all the road elements in the HD map must be correctly defined to construct the correct road network necessary to generate the global path. But unfortunately, it is not difficult to find various errors even in the most recent HD maps. Hence, a preprocessing algorithm has been developed to detect and correct errors in the HD map. This error detection and correction result in constructing the correct road network for use in global path planning. Furthermore, the algorithm was tested on real roads' HD maps, demonstrating its validity.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.220-220
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• 2022

물관리 일원화, 물관리기본법 제정·시행 등 우리나라 물관리 체계의 혁신기에 정책의 구심점 역할을 수행할 통합 물관리 전략 마련이 요구됨에 따라, 최근 관계부처 합동으로 「제1차 국가물관기본계획(2021~2030)」을 수립하여 공표·발간되었다. 국가물관리기본계획에서는 유역단위의 물관리를 원칙(12대 기본원칙 중(中))로 하며, 물관리 3대분야(수질·수생태, 이수, 치수)에 대한 추진전략을 수립하였다. 또한, 지속가능한 물관리 체계를 구축하기 위해 추진전략별 주요 관리지표를 설정하였으며, 이를 통해 물관리 방향을 정립하고 분야별 관련 및 하위계획과의 일관성·정합성을 유지하고자 하였다. 이에 본 연구에서는 추진전략별 주요 관리지표 중, 유역 재해안전도와 관련하여 하천범람에 대한 기존의 치수안전도의 한계점을 검토하고 유역단위의 치수관리 현황을 평가 할 수 있는 방안을 마련하고자 하였다. 과거 유역종합치수계획에서의 치수안전도는 홍수피해잠재능(PFD)을 적용하여 등급별 홍수방어대책 수립방향 및 하천의 설계빈도 조정을 검토하였으며, 홍수피해잠재능(PFD)의 실무적 적용 어려움(산정인자 다(多)), 설계빈도와의 연계성 부족, 치수단위구역의 공간적 정확성 미흡 등에 대한 개선·보완의 의견이 제기되어 왔다. 또한, 유역내 전체하천이 아닌 주요 하천을 대상으로만 치수안전도 설정하여 유역단위의 치수관리에 한계가 있으며, 하천 전체구간의 설계빈도 상향에 따른 홍수방어대책이 비경제적인 것으로 판단된다. 따라서, 기존의 치수안전도의 한계점을 개선하기 위하여 홍수피해잠재능(PFD)의 산정인자 단순화, 홍수위험지도를 활용을 통한 치수단위구역의 공간적 정확도 향상 및 치수단위구역별 설계빈도 조정 가능 등의 개선방안을 검토하였으며, 빈도별 치수단위구역의 홍수피해잠재능(PFD)의 통계적 특성 분석을 통해 등급 설정 및 설계빈도 조정 기준을 제시하였다. 그리고 유역내 전체하천에 대한 치수단위구역별 치수안전도를 설정하고, 중권역 단위의 치수안전도를 평가하여 유역단위의 치수관리 현황을 정량적으로 제시함에 유역 재해안전도로 활용이 가능할 것으로 판단된다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.501-508
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• 2023

Addressing urban noise problems, this study develops eco-friendly, inorganic sound-absorbing panels, overcoming the limitations of traditional PMMA and cement-based panels. These conventional panels pose safety risks due to flammability and environmental concerns due to carbon emissions. Utilizing industrial waste, the research comprises two phases: initial tests for physical and performance characteristics (fluidity, density, compressive strength, sound absorption) and subsequent development of optimized panel mixtures. This approach aims to replace existing panels with sustainable, effective alternatives, significantly contributing to safer, environmentally responsible urban infrastructure. The findings of this study have implications for the sound panel market, offering novel solutions for noise control while aligning with environmental and safety standards.

• Economic and Environmental Geology
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• v.56 no.5
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• pp.565-580
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• 2023

In this study, we reviewed and summarized comprehensive roles and importance of natural analogue studies for demonstrating the safety and improving the reliability of the safety for the deep geological disposal of high-level radioactive waste. We also investigated domestic and foreign status of natural analogue studies in order to study and substantiate complex and various radionuclide behaviors in subsurface disposal environments. In addition, we investigated and uranium behaviors in groundwater and rock in uranium deposits including domestic uranium deposits in Ogcheon Metamorphic Belt and biogeochemical interactions in geological environments. Although there are many limitations and uncertainties in directly using the information and data for uranium behaviors obtained from uranium deposits in the disposal safety assessment, the information and data can be utilized in the disposal safety assessment and safety case construction both in qualitative and partly quantitative ways.

• Journal of the Korea Institute of Building Construction
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• v.23 no.6
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• pp.831-839
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• 2023

This study aims to develop a framework for an accident prediction model leveraging a deep neural network algorithm, specifically tailored for small-scale construction sites. Notably, the incidence of accidents in the construction sector is markedly higher compared to other industries, with a significant contribution from small-scale sites. The challenging nature of construction in urban settings, coupled with the increasing frequency of adverse weather conditions, is likely to escalate accident risks at these sites. Anticipating and mitigating accidents at small-scale construction sites is therefore crucial to decrease the overall industry accident rate. Consequently, this research introduces a Deep Neural Network-based model for forecasting accidents at small-scale construction sites. The framework and findings of this study are poised to serve as a guideline for the safety management of small-scale construction projects, ultimately aiding in the realization of safer, more sustainable construction practices at these sites.

• Journal of Korea Water Resources Association
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• v.57 no.1
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• pp.21-33
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• 2024

Recently, the patterns of climate change-induced disasters have become more diverse and extensive. To develop an effective flood control plan, Korea has incorporated the concept of Potential Flood Damage (PFD) into the Long-Term Comprehensive Water Resources Plan to assess flood risk. However, concerns regarding the PFD have prompted numerous studies. Previous research primarily focused on modifying and augmenting the PFD index or introducing new indices. This study aims to enhance the existing flood control safety evaluation method by utilizing a flood risk map that incorporates risk indices, specifically focusing on the Yeong-Seomjin river basin. The study introduces three main evaluation approaches: risk and potential analysis, PFD and flood management level analysis, and flood control safety evaluation. The proposed improved evaluation method is expected to be instrumental in evaluating various flood control safety measures and formulating flood control plans.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.15-20
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• 2024

The utilization of small unmanned aerial vehicles (UAVs) has expanded into both military and civilian domains, increasing the necessity for research to ensure operational safety and the efficient utilization of airspace. In this study, the calculation of minimum separation distances for the safe operation of small UAVs at low altitudes was conducted. The determination of minimum separation distances requires a comprehensive analysis of the total system errors associated with small UAVs, necessitating sensitivity analysis to identify key factors contributing to flight technology errors. Flight data for small UAVs were acquired by integrating the control system of an actual small UAV with a flight simulation program. Based on this data, operational scenarios for small UAVs were established, and the minimum separation distances for each scenario were calculated. This research contributes to proposing methods for utilizing calculated minimum separation distances as crucial parameters for ensuring the safe operation of small unmanned aerial vehicles in real-world scenarios.