• 대한의용생체공학회:의공학회지
• /
• 제43권4호
• /
• pp.193-198
• /
• 2022

Contrast enhanced magnetic resonance imaging using gadolinium-based contrast agent (GBCA) is a very useful in vivo technique to visualize the inner ear pathology including endolymphatic hydrops. Although systemic intravenous (IV) administration can visualize the perilymph space, the visualization was possible by indirect passage of contrast agent through blood-perilymph barrier. All animal experimental procedures were performed under anesthesia with 5% isoflurane. Lipopolysaccharide (LPS) was instilled into the left tympanic cavity through the tympanic membrane using a sterile 27gauge needle to induce hydrops model. Tucker-Davis Technologies system was used to measure Auditory Brainstem Responses (ABRs). For intracerebroven-tricular (ICV) administration, 25 µmol of GADOVIST (Bayer, Berlin, Germany) was used and diluted GADOVIST injection was 10 µl. MR imaging was acquired with a 9.4 Tesla MRI scanner. Transmit-receive volume coil with 40 mm inner diameter and 75 mm out diameter was used. ICV administration well demonstrated the strong enhancement along the cerebrospinal fluid (CSF) microcirculation pathway including CSF fluid in the subarachnoid space and CSF space of the inner ear structures. On the other hand, IV administration showed no contrast enhancement along the CSF microcirculation pathway and showed weak enhancement in the inner ear structures. In case of rat hydrops model, ICV administration showed that the reduced contrast enhancement in the perilymph space of the hydrops induced inner ear compared to the contrast enhancement in the perilymph space of the normal inner ear. New systemic ICV administration method provide contrast enhancement of GBCA in the inner ear through CSF microcirculation pathway.

• 국제학술발표논문집
• /
• The 9th International Conference on Construction Engineering and Project Management
• /
• pp.170-178
• /
• 2022

A high-performing Earned Value Management System (EVMS) can influence project success and help stakeholders meet project objectives. Although EVMS processes are well-supported by technical guidelines and standards, project managers often face challenges related to the project culture, team, resources, and business practices that make up the project environment within which an EVMS is being used. A comprehensive literature review revealed a lack of a data-driven and consistent assessment frameworks that can gauge the environment surrounding EVMS implementation. This paper will discuss the EVMS environment of construction and environmental projects, and examine its impact on cost performance. The authors used a multi-method approach to identify 27 environment factors that make up the EVMS environment, assessing them on 18 construction and environmental projects worth over $2 billion of total cost. Research methods employed include: (1) a literature review of more than 300 references; (2) a survey of 294 respondents; and (3) remote research charrettes with more than 60 participating expert practitioners. Culture (one of the identified environment categories) was found to be relatively more important in terms of its impact on the EVMS environment, followed by people, practices, and resources. These exploratory results show statistically significant differences in cost performance between completed projects with either a good or poor environment, for the sample projects. Key environment factors are outlined, and guidance is provided to practitioners around how to set up an effective EVMS environment in a construction or environmental project to inform decision-making and support achieving the project cost objectives successfully.

• 한국의학물리학회지:의학물리
• /
• 제33권1호
• /
• pp.1-9
• /
• 2022

Purpose: To evaluate the effective volume of the Korea Research Institute of Standards and Science free air chamber (KRISS FAC) L1 used for the primary standard device of the low-energy X-ray air kerma. Methods: The mechanical dimensions were measured using a 3-dimensional coordinate measuring machine (3-d CMM, Model UMM 500, Carl Zeiss). The diameter of the diaphragm was measured by a ring gauge calibrator (Model KRISS-DM1, KRISS). The elongation of the collector length due to electric field distortion was determined from the capacitance measurement of the KRISS FAC considering the result of the finite element method (FEM) analysis using the code QuickField v6.4. Results: The measured length of the collector was 15.8003±0.0014 mm with a 68% confidence level (k=1). The aperture diameter of the diaphragm was 10.0021±0.0002 mm (k=1). The mechanical measurement volume of the KRISS FAC L1 was 1.2415±0.0006 cm³ (k=1). The elongated length of the collector due to the electric field distortion was 0.170±0.021 mm. Considering the elongated length, the effective measurement volume of the KRISS FAC L1 was 1.2548±0.0019 cm³(k=1). Conclusions: The effective volume of the KRISS FAC L1 was determined from the mechanically measured value by adding the elongated volume due to the electric field distortion in the FAC. The effective volume will replace the existing mechanically determined volume in establishing and maintaining the primary standard of the low-energy X-ray.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2022년도 학술발표회
• /
• pp.329-329
• /
• 2022

Accurate characterization of terrestrial precipitation variation from high spatial resolution satellite sensors is beneficial for urban hydrology and microscale agriculture modeling, as well as natural disasters (e.g., urban flooding) early warning. However, the widely-used top-down approach for precipitation retrieval from microwave satellites is limited in several hydrological and agricultural applications due to their coarse spatial resolution. In this research, we aim to apply a novel bottom-up method, the parameterized SM2RAIN, where precipitation can be estimated from soil moisture signals based on an inversion of water balance model, to generate high spatial resolution terrestrial precipitation estimates at 0.01º grid (roughly 1-km) from the C-band SAR Sentinel-1. This product was then tested against a common reanalysis-based precipitation data and a domestic rain gauge network from the Korean Meteorological Administration (KMA) over central South Korea, since a clear difference between climatic types (coasts and mainlands) and land covers (croplands and mixed forests) was reported in this area. The results showed that seasonal precipitation variability strongly affected the SM2RAIN performances, and the product derived from separated parameters (rainy and non-rainy seasons) outperformed that estimated considering the entire year. In addition, the product retrieved over the mainland mixed forest region showed slightly superior performance compared to that over the coastal cropland region, suggesting that the 6-day time resolution of S1 data is suitable for capturing the stable precipitation pattern in mainland mixed forests rather than the highly variable precipitation pattern in coastal croplands. Future studies suggest comparing this product to the traditional top-down products, as well as evaluating their integration for enhancing high spatial resolution precipitation over entire South Korea.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2022년도 학술발표회
• /
• pp.141-141
• /
• 2022

Drought is a global phenomenon that affects almost all landscapes and causes major damages. Due to non-linear nature of contributing factors, drought occurrence and its severity is characterized as stochastic in nature. Early warning of impending drought can aid in the development of drought mitigation strategies and measures. Thus, drought forecasting is crucial in the planning and management of water resource systems. The primary objective of this study is to make improvement is existing drought forecasting techniques. Therefore, we proposed an improved version of Seasonal Autoregressive Integrated Moving Average (SARIMA) model (MD-SARIMA) for reliable drought forecasting with three years lead time. In this study, we selected four watersheds of Han River basin in South Korea to validate the performance of MD-SARIMA model. The meteorological data from 8 rain gauge stations were collected for the period 1973-2016 and converted into watershed scale using Thiessen's polygon method. The Standardized Precipitation Index (SPI) was employed to represent the meteorological drought at seasonal (3-month) time scale. The performance of MD-SARIMA model was compared with existing models such as Seasonal Naive Bayes (SNB) model, Exponential Smoothing (ES) model, Trigonometric seasonality, Box-Cox transformation, ARMA errors, Trend and Seasonal components (TBATS) model, and SARIMA model. The results showed that all the models were able to forecast drought, but the performance of MD-SARIMA was robust then other statistical models with Wilmott Index (WI) = 0.86, Mean Absolute Error (MAE) = 0.66, and Root mean square error (RMSE) = 0.80 for 36 months lead time forecast. The outcomes of this study indicated that the MD-SARIMA model can be utilized for drought forecasting.

• 한국산업정보학회논문지
• /
• 제28권6호
• /
• pp.21-27
• /
• 2023

현대 함정은 외부로 방사되는 적외선 신호를 낮추기 위해 폐기관에 적외선 신호저감 장치(Infra-Red Signature Suppression system, IRSS)를 설치한다. 그리고 함정은 생의 주기가 매우 긴 전략 자산으로 탑재 장비들의 성능에 대한 높은 신뢰성을 충분히 확보해야 한다. 따라서, IRSS와 같은 장비들은 설계 단계에서 모형시험을 통해 성능평가를 하고 있다. IRSS의 모형시험에서는 다양한 계측기기들이 사용된다. 그러므로, 모형시험 단계 이전에 계측기들의 신뢰성을 평가해야 한다. 본 연구에서는 IRSS 모형시험에 사용되는 계측 장비들의 신뢰성 평가에 관한 연구를 수행하였다. 시험 장비와 계측기는 열 풍동 시험기, 피토 튜브와 디지털 차압계, 열전대 센서 그리고 디지털 기록계가 사용되었다. 계측 결과 열 풍동 시험기의 풍속이 증가할수록 유동의 계측 편차가 감소하였으며, 열전대 센서의 온도는 사용 방법에 따라 반응 속도 및 민감도의 차이를 보였다.

• 대한토목학회논문집
• /
• 제43권6호
• /
• pp.851-863
• /
• 2023

일정 규모 이상의 공공 건설 프로젝트에 대한 BIM(Building Information Model) 적용이 의무화됨에 따라 입찰단계에서부터 BIM 요구사항에 대한 관련 절차 및 기술에 대한 폭넓은 이해가 요구되고 있다. 그러나 대부분의 중소 시공 및 엔지니어링 기업은 BIM 수행역량이 낮고 관련 기존 업무 프로세스의 BIM 적용에 대한 이해 높지 않아, 입찰 요구사항에 대한 인지가 어렵고 입찰단계의 합리적인 의사결정이 쉽지 않다. 따라서 본 연구는 BIM 입찰문서 용어를 포함한 형태소 분석기를 딥러닝 모델에 결합하여 입찰문서의 BIM 요구사항의 난이도 판별 방법을 제시한다. 제안된 딥러닝 모델의 매개변수 영향이 조사되었으며 예측 결과의 타당성이 검토되었다. 그 결과, 제안된 모델이 시험 데이터에 대해 F1-score 0.83의 성능을 가지며, 모델의 판별 결과 또한 실제 BIM 수행 난이도를 타당하게 반영하고 있음을 보였다.

• 한국동물생명공학회지
• /
• 제38권3호
• /
• pp.143-150
• /
• 2023

Background: The successful production of superior or transgenic offspring from in vitro produced embryos in cattle relies heavily on the quality of blastocyst stage embryos. In order to enhance the developmental competency of these embryos, a novel culture method was devised. Methods: This study utilized stem cell culture medium (SCM) from hESCs as a supplement within the culture medium for bovine in vitro produced embryos. To gauge the efficacy of this approach, in vitro fertilized embryos were subjected to culture in CR1aa medium enriched with one of three supplements: 0.3% BSA, 10% FBS, or 10% SCM. Results: The blastocyst development and hatching rates of one-cell zygotes cultured in CR1aa medium supplemented with SCM (23.9% and 10.2%) surpassed those cultured in CR1aa medium supplemented with BSA (9.3% and 0.0%) or FBS (3.1% and 0.0%) (p < 0.05). Furthermore, post-zygotic gene activation, cleaved embryos cultured in CR1aa medium supplemented with SCM (57.8% and 34.5%) exhibited notably higher rates (p < 0.05) compared to those cultured with BSA (12.9% and 0.0%) or FBS (45.7% and 22.5%) supplementation. Furthermore, the microinjection of SCM into the cytoplasm or pronucleus of fertilized zygotes resulted in elevated blastocyst development and hatching rates, particularly when the microinjected embryos were subsequently cultured in CR1aa medium supplemented with SCM from the 8-cell embryo stage onwards (p < 0.05), in contrast to those cultured with FBS supplementation. Conclusions: In conclusion, this study conclusively demonstrated that the incorporation of SCM into the culture medium significantly enhances the developmental progress of preimplantation embryos.

• 터널과지하공간
• /
• 제33권6호
• /
• pp.495-507
• /
• 2023

불연속면 거칠기는 암반의 기계적 특성에 큰 영향을 주며 열·수리 역학적 거동에도 많은 영향을 미치는 요소이다. 본 연구에서는 입체사진측량기법을 이용하여 불연속면에 대한 3차원 점군 데이터를 생성시키고 이를 이용하여 불연속면의 거칠기 특성화를 수행하였다. 3차원 점군 데이터로 재생성된 불연속면 프로파일과 프로파일 게이지를 이용하여 수동으로 측정한 프로파일을 비교하여 취득한 점군 데이터가 암반면의 실제 형상을 정확하게 재현하였는지 평가하였다. 또한, 측정 프로파일수가 거칠기 평가에 미치는 영향에 대해 분석하였고, 거칠기의 이방성 평가방법을 제안하고 실제 암반 불연속면에 대한 거칠기 이방성 평가를 수행하였다.

• 한국수자원학회논문집
• /
• 제33권2호
• /
• pp.247-262
• /
• 2000

본 연구에서는 낙동강유역의 주요 수위표지점중 진동수위표지점에서 홍수위를 예측하기위한 신경망모형인 WSANN모형이 제시되었다. WSANN모형은 모멘트방법, 초기조건의 개선 및 적응학습속도에 의해 보완되어진 개선된 역전파훈련 알고리즘을 이용하였고, 본 연구에 사용된 자료는 훈련자료와 테스팅자료로 분할하였으며, 최적 은닉층 노드수를 결정하기 위하여 은닉층노드와 임계학습횟수로부터 경험식이 유도되었다. 그리고 WSANN모형의 보정은 4개의 훈련자료에 의해 실시되었으며, WSANN22와 WSANN32모형이 모델의 검증에 사용될 최적모형으로 결정되었다. 모형의 검증은 훈련되지 않은 2개의 테스팅자료를 이용하여 모형의 적합성을 평가하기 위하여 이루어 졌으며, 통계분석의 결과를 통하여 홍수위를 합리적으로 예측하는 것으로 나타났다. 따라서 본 연구의 결과를 기본으로 신경망기법을 이용한 실시간 홍수예경보 시스템의 구축 및 홍수위의 제어에 관한 지속적인 연구가 필요것으로 사료된다.