• 한국환경보건학회지
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• 제48권3호
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• pp.151-158
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• 2022

Background: Chemical emissions in the environment have rapidly increased with the accelerated industrialization taking place in recent decades. Residents of industrial complexes are concerned about the health risks posed by chemical exposure. Objectives: This study was performed to suggest modeling methods that take into account multimedia and multi-pathways in human exposure and risk assessment. Methods: The concentration of benzene emitted at industrial complexes in Daesan, South Korea and the exposure of local residents was estimated using the Caltox model. The amount of human exposure based on inhalation rate was stochastically predicted for various activity stages such as resting, normal walking, and fast walking. Results: The coefficient of determination (R²) for the CalTOX model efficiency was 0.9676 and the root-mean-square error (RMSE) was 0.0035, indicating good agreement between predictions and measurements. However, the efficiency index (EI) appeared to be a negative value at -1094.4997. This can be explained as the atmospheric concentration being calculated only from the emissions from industrial facilities in the study area. In the human exposure assessment, the higher the inhalation rate percentile value, the higher the inhalation rate and lifetime average daily dose (LADD) at each activity step. Conclusions: Prediction using the Caltox model might be appropriate for comparing with actual measurements. The LADD of females was higher ratio with an increase in inhalation rate than those of males. This finding would imply that females may be more susceptible to benzene as their inhalation rate increases.

• 한국컴퓨터정보학회논문지
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• 제14권12호
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• pp.139-145
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• 2009

본 논문에서는 관리자가시스템 운영과 감사 측면에서 침해사고에 대응하고 사고 발생 즉시 포렌식 데이터를 수집 분석 및 복구할 수 있는 포렌식 데이터의 실시간 수집 절차 모델을 제안한다. 제안한 모델은 기능 요소별로 구별된 7단계 절차를 가지며 추상적이고 관리적인 기존의 포렌식 절차와는 달리, 관리자가 시스템 운영과 감사 측면에서 침해사고에 대응하고, 사고 발생시 포렌식 데이터를 수집 분석 및 복구할수 있는 절차들이 포함되어 있다. 또한 즉각적인 대응이 어려운 경우 기존의 절차와 마찬가지로 종합적이고 조직적인 대응이 가능하도록 대응 전략 체계화 단계를 통한 포렌식 데이터 수집 단계로의 피드백 절차를 둔다.

• 한국전문물리치료학회지
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• 제30권2호
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• pp.120-127
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• 2023

Background: In general, measurement qualities of cross-culturally adapted quality of life (QOL) measures are altered in many aspects, although versions of them are well-validated measures. The latent trait and measurement qualities of the QOL measures for cancer-related samples should be considered when developing cross-culturally adapted measures. Objects: To investigate the latent trait of the translated into Korean World Health Organization Quality of Life-BREF (WHOQOL-BREF) administered to different cancer survivors who had palliative rehabilitation care service (PRCS). Methods: A cross-sectional study with 139 cancer survivors who had an experience of cancer survivorship with PRCS were conducted with a two-step analytic procedure including exploratory factor analysis (EFA) to confirm the latent trait and Rasch rating scale modeling to investigate the measurement qualities of the cross-culturally adapted WHOQOL-BREF measure. Results: While the original WHOQOL-BREF measure constitutes a 4-latent trait, the EFA reveals that 24 items constitute six substantial factors. The item loadings are predominantly spread over factors 1 through 4 in a mixed manner of the latent traits, while the loadings of 'physical health' and 'environmental health' latent traits show similarity to what the original measure intended to assess. The latent trait of the cross-culturally adapted WHOQOL-BREF measure administered to different cancer survivors is likely to reveal more dimensions than the original WHOQOL-BREF measure. Person reliability (i.e., analogous to Cronbach's alpha) and separation are measured with 0.92 and 3.48, respectively. All items except the one item (medical treatment item) fit the Rasch rating model. Conclusion: Findings suggest that the latent trait and the measurement qualities of the cross-culturally adapted WHOQOL-BREF measure should be taken into consideration when applying versions of it to various populations.

• 해양환경안전학회지
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• 제29권3호
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• pp.281-287
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• 2023

Establishing a ship's passage plan is an essential step before it starts to sail. The research related to the automatic generation of ship passage plans is attracting attention because of the development of maritime autonomous surface ships. In coastal water navigation, the land, islands, and navigation rules need to be considered. From the path planning algorithm's perspective, a ship's passage planning is a global path-planning problem. Because conventional global path-planning methods such as Dijkstra and A^* are time-consuming owing to the processes such as environmental modeling, it is difficult to modify a ship's passage plan during a voyage. Therefore, the D^* algorithm was used to address these problems. The starting point was near Busan New Port, and the destination was Ulsan Port. The navigable area was designated based on a combination of the ship trajectory data and grid in the target area. The initial path plan generated using the D^* algorithm was analyzed with 33 waypoints and a total distance of 113.946 km. The final path plan was simplified using the Douglas-Peucker algorithm. It was analyzed with a total distance of 110.156 km and 10 waypoints. This is approximately 3.05% less than the total distance of the initial passage plan of the ship. This study demonstrated the feasibility of automatically generating a path plan in coastal navigation for maritime autonomous surface ships using the D^* algorithm. Using the shortest distance-based path planning algorithm, the ship's fuel consumption and sailing time can be minimized.

• 지적과 국토정보
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• 제53권1호
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• pp.21-36
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• 2023

전 세계적으로 가장 널리 사용되고 있는 교통수요모형은 전통적 4단계 교통수요모델이다. 하지만, 기존 분석방법은 시공간적으로 다양한 분석에 제약을 가지고 있으며, 이러한 한계를 극복하기 위해 최근 활동기반 모형 및 시스템이 활발히 연구 개발되고 있다. 이에 본 연구에서는 빅데이터를 활용한 활동기반 통행자분석시스템 ABATA(Activity-Based Traveler Analyzer) 기술개발을 소개한다. 이 시스템은 시간별 총인구 추정, 활동 프로파일 생성, 시간별 활동 인구 추정, 공간 활동 인구 추정 및 출발지·목적지 추정 등의 구성요소를 포함한다. 제안된 시스템을 실증하기 위해 사례연구로 세종시 5-1 블록스마트시티를 대상으로 토지이용변화에 따른 배기가스 배출영향을 평가하였다. 그 결과 업무시설 분산계획 시나리오의 토지이용이 업무시설 집중계획 시나리오보다 이동 거리가 길어 배출량이 더 많이 발생하는 것으로 나타났다. 제안된 ABATA 시스템은 활동 인구 및 통행 수요에 대한 인구, 활동 일정 및 미래 토지이용의 변화 영향을 시뮬레이션하기 위한 유용한 도구를 제공할 것으로 기대된다.

• Safety and Health at Work
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• 제14권2호
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• pp.229-236
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• 2023

Background: In workers with moderate to severe work-related traumatic brain injury (wrTBI), this study aimed to investigate the effect of the timing of rehabilitation therapy initiation on the length of hospital stay and the factors that can influence this timing. Methods: We used data obtained from the Republic of Korea's nationwide Workers' Compensation Insurance. In the Republic of Korea, between the years 2010 and 2019, a total of 26,324 workers filed a claim for compensation for moderate to severe wrTBI. Multiple regression modeling was performed to compare the length of hospital stay according to the timing of rehabilitation therapy initiation following wrTBI. According to the timing of the initiation of rehabilitation therapy following TBI, the proportions of healthcare institutions that provided medical care during each admission step were compared. Results: The length of hospital stay for workers who started rehabilitation therapy within 90 days was significantly shorter than that for workers who started rehabilitationment were first admitted to tertiary hospitals. Approximately 39% of patients who received delayed rehabilitation treatment were first admitted to general hospitals, and 28.5% were first admitted to primary hospitals. Conclusions: Our findings demonstrate the importance of early rehabilitation initiation and that the type of healthcare institution that the patient is first admitted to after wrTBI may influence the timing of rehabilitation initiation. The results of this study also emphasize the need to establish a Worker's Compensation Insuranceespecialized rehabilitation healthcare delivery system.

• Korean Chemical Engineering Research
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• 제61권4호
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• pp.598-603
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• 2023

촉매를 사용한 전기화학적 암모니아 생산은 주변 온도 및 압력 조건, 환경 친화적인 작동 및 고순도 암모니아 생산을 가능하게 함으로써 전통적인 하버-보쉬 방법을 대체할 대안으로서 가능성이 있다. 본 연구에서는 제1원리 계산을 사용하여 루테늄 촉매의 표면에서 발생하는 질소 환원 반응에 초점을 맞춘다. 루테늄의 (0001) 및 (1000) 표면에서 질소 환원에 대한 반응 경로를 모델링하여 반응 구조를 최적화하고 각 단계에 대한 유리한 경로를 예측했다. 각 표면에서의 N₂의 흡착 구성은 후속 반응 활동에 상당한 영향을 미쳤으며, 깁스자유에너지 분석은 가장 유리한 질소 환원 구성을 도출하였다. 루테늄의 (0001) 표면에서는 질소 분자가 표면에 수직으로 흡착하는 end-on 형태가 가장 유리한 N₂ 흡착에너지가 나타났으며 유사하게, (1000) 표면에서도 end-on 형태가 안정적인 흡착 에너지 값을 보였다. 이어서, distal 및 alternating 구성 모두에서 최적화된 수소 흡착을 통해 NH₃의 최종 탈착까지 이론적으로 완전한 반응 경로를 설명했다.

• 한국음향학회지
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• 제29권1호
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• pp.56-61
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• 2010

본 논문에서는 HMM 기반의 연속음성인식에서 음향모델의 최적화 기법을 논한다. 대부분의 음성인식 시스템에서 HMM 상태별로 동일한 개수의 가우시안 성분 (mixture component)을 사용해 왔다. 그러나, 음향 모델링에 사용되는 데이터 샘플의 개수는 HMM상태별로 다르므로 이에 따른 최적화를 수행할 경우 모델 파라미터의 개수를 효과적으로 줄일 수 있을 뿐 아니라, 디코딩 단계에서 음성인식기의 속도 및 인식 성능 개선이 기대된다. 본 연구에서 제안한 방법은 기존에 알려진 MDL (minimum description length) 기반의 음향모델 최적화 방법에서 가우시안 성분들의 통합과정에 가우시안 성분의 가중치 정보 (mixture weight)를 반영하도록 개선하였다. 인식 실험 결과, 제안한 방법은 가우시안 성분의 가중치를 반영하지 않는 기존 방법에 비해 향상된 최적화 성능을 보임을 확인할 수 있었다.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.973-979
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• 2024

In the framework of the Generation IV research and development project, in which the French Commission of Alternative and Atomic Energies (CEA) is involved, a main objective for the design of Sodium-cooled Fast Reactor (SFR) is to meet the safety goals for severe accidents. Among the severe ones, the Unprotected Transient OverPower (UTOP) accidents can lead very quickly to a global melting of the core. UTOP accidents can be considered either as slow during a Control Rod Withdrawal (CRW) or as fast. The paper focuses on fast UTOP accidents, which occur in a few milliseconds, and three different scenarios are considered: rupture of the core support plate, uncontrolled passage of a gas bubble inside the core and core mechanical distortion such as a core flowering/compaction during an earthquake. Several levels and rates of reactivity insertions are also considered and the thermal-mechanical behavior of an ASTRID fuel pin from the ASTRID CFV core is simulated with the GERMINAL code. Two types of fuel pins are simulated, inner and outer core pins, and three different burn-up are considered. Moreover, the feedback from the CABRI programs on these type of transients is used in order to evaluate the failure mechanism in terms of kinetics of energy injection and fuel melting. The CABRI experiments complete the analysis made with GERMINAL calculations and have shown that three dominant mechanisms can be considered as responsible for pin failure or onset of pin degradation during ULOF/UTOP accident: molten cavity pressure loading, fuel-cladding mechanical interaction (FCMI) and fuel break-up. The study is one of the first step in fast UTOP accidents modelling with GERMINAL and it has shown that the code can already succeed in modelling these type of scenarios up to the sodium boiling point. The modeling of the radial propagation of the melting front, validated by comparison with CABRI tests, is already very efficient.

• 방사선산업학회지
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• 제17권2호
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• pp.173-181
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• 2023

3D printing is a technology that can transform and process computerized data obtained through modeling or 3D scanning via CAD. In the medical field, studies on customized 3D printing technology for clinical use or patients and diseases continue. The importance of research on filaments and molding methods is increasing, but research on manufacturing methods and available raw materials is not being actively conducted. In this study, we compare the characteristics of each material according to the manufacturing method of the phantom manufactured with 3D printing technology and evaluate its usefulness. We manufactured phantoms of the same size using poly methyl meta acrylate (PMMA), acrylonitrile butadiene styrene (ABS), and Poly Lactic Acid (PLA) based on the international standard phantom of aluminum step wedge. We used SITEC's radiation generator (DigiRAD-FPC R-1000-150) and compared the shielding rate and line attenuation coefficient through the average after shooting 10 times. As a result, in the case of the measured dose transmitted through each phantom, it was confirmed that the appearance of the dose measured for phantoms decreased linearly as the thickness increased under each condition. The sensitivity also decreased as the steps increased for each phantom and confirmed that it was different depending on the thickness and material. Through this study, we confirmed that 3D printing technology can be usefully used for phantom production in the medical field. If further development of printing technology and studies on various materials are conducted, it is believed that they will contribute to the development of the medical research environment.