• 전력전자학회논문지
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• 제26권3호
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• pp.183-191
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• 2021

A battery management system (BMS) provides some functions for ensuring safety and reliability that includes algorithms estimating battery states. Given the changes caused by various operating conditions, the state-of-health (SOH), which represents a figure of merit of the battery's ability to store and deliver energy, becomes challenging to estimate. Machine learning methods can be applied to perform accurate SOH estimation. In this study, we propose a Long-Term Recurrent Convolutional Network (LRCN) that combines the Convolutional Neural Network (CNN) and Long Short-term Memory (LSTM) to extract aging characteristics and learn temporal mechanisms. The dataset collected by the battery aging experiments of NASA PCoE is used to train models. The input dataset used part of the charging profile. The accuracy of the proposed model is compared with the CNN and LSTM models using the k-fold cross-validation technique. The proposed model achieves a low RMSE of 2.21%, which shows higher accuracy than others in SOH estimation.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.669-677
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• 2022

In this paper, different types of traditional project delivery methods in the construction industry were explored and a comparative analysis against Integrated Project Delivery (IPD) were performed. The advantages of IPD method for all parties, owner/engineer/architect/general contractor, were explored by reviewing the most recent literature. The literature suggests that IPD method should be the dominating project delivery method and diluting the conventional methods such as Design-Bid-Build due to more collaborative and mutually beneficial ways of doing construction; IPD is newer and a more comprehensive method to capture the intrinsic values of project collaboration. This paper presents a comparison of the commonly used methods of project delivery, Design-bid-build, CMAR, & Design-Build and addresses their advantages and disadvantages in differing project scopes and sizes. Several industry leaders with experience in the four types of project delivery addressed were surveyed. The survey results show an overwhelming desire for future projects to go toward IPD from the contractor/owner/RDP. The biggest obstacle facing a project from using IPD appears to be trust.

• Anatomy and Cell Biology
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• 제57권1호
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• pp.61-69
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• 2024

Hypogonadism is associated with an increased risk of coronary artery disease. This study sought to describe the histomorphology of the left coronary arteries of the adult male rabbit following orchiectomy and subsequent testosterone administration. We included 20 adult male rabbits, divided into a baseline group (n=2), an interventional group subjected to castration only (n=6), an intervention group subjected to castration followed by testosterone injection (n=6), and a control group (n=6). Key variables under investigation were serum testosterone levels, the intima-media thickness of coronary arteries, smooth muscle cell density, and adventitial collagen fiber density. The mean coronary arteries' intimal medial thickness was significantly higher in the castrated group than in controls (0.488 mm and 0.388 mm, respectively), while the testosterone-injected group had a mean of 0.440 mm. Mean smooth muscle cell density was significantly lower in the castrated rabbits vs. controls (26.96% and 47.80%, respectively), this observation being reversed with testosterone injection (47.53%). Mean adventitial collagen fiber density was significantly higher in the castrated group than in controls (66.6% and 36.1%, respectively), with a marginal difference after testosterone injection (65.2%). This study demonstrates that castrationinduced hypogonadism causes morphological changes in the coronary arteries that are partly reversible using testosterone injections. These findings provide a morphological basis for understanding the role of testosterone in coronary arteries.

• International Journal of Aeronautical and Space Sciences
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• 제14권2호
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• pp.122-132
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• 2013

In this research the development of unstructured grid discretization solution techniques is presented. The purpose is to describe such a conservative discretization scheme applied for experimental validation work. The objective of this paper is to better establish the effects of mesh generation techniques on velocity fields and particle deposition patterns to determine the optimal aerodynamic characteristics. In order to achieve the objective, the mesh surface discretization approaches used the VLA prototype manufacturing tolerance zone of the outer surface. There were 3 schemes for this discretization study implementation. They are solver validation, grid convergence study and surface tolerance study. A solver validation work was implemented for the simple 2D and 3D model to get the optimum solver for the VLA model. A grid convergence study was also conducted with a different growth factor and cell spacing, the amount of mesh can be controlled. With several amount of mesh we can get the converged amount of mesh compared to experimental data. The density around surface model can be calculated by controlling the number of element in every important and sensitive surface area of the model. The solver validation work result provided the optimum solver to employ in the VLA model analysis calculation. The convergence study approach result indicated that the aerodynamic trend characteristic was captured smooth enough compared with the experimental data. During the surface tolerance scheme, it could catch the aerodynamics data of the experiment data. The discretization studies made the validation work more efficient way to achieve the purpose of this paper.

• 대기
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• 제21권4호
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• pp.415-427
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• 2011

In this study, the impacts of land surface conditions, land cover (LC) map and leaf area index (LAI), on the short-range weather forecast over the East-Asian region were examined using Unified Model (UM) coupled with the MOSES 2.2 (Met-Office Surface Exchange Scheme). Four types of experiments were performed at 12-km horizontal resolution with 38 vertical layers for two months, July and August 2009 through consecutive reruns of 72-hour every 12 hours, 00 and 12 UTC. The control experiment (CTRL) uses the original IGBP (International Geosphere-Biosphere Programme) LC map and old MODIS (MODerate resolution Imaging Spectroradiometer) LAI, the new LAI experiment (NLAI) uses improved monthly MODIS LAI. The new LC experiment (NLCE) uses KLC_v2 (Kongju National Univ. land cover), and the new land surface experiment (NLSE) uses KLC_v2 and new LAI. The reduced albedo and increased roughness length over southern part of China caused by the increased broadleaf fraction resulted in increase of land surface temperature (LST), air temperature, and sensible heat flux (SHF). Whereas, the LST and SHF over south-eastern part of Russia is decreased by the decreased needleleaf fraction and increased albedo. The changed wind speed induced by the LC and LAI changes also contribute the LST distribution through the change of vertical mixing and advection. The improvement of LC and LAI data clearly reduced the systematic underestimation of air temperature over South Korea. Whereas, the impacts of LC and LAI conditions on the simulation skills of precipitation are not systematic. In general, the impacts of LC changes on the short range forecast are more significant than that of LAI changes.

• 한국콘텐츠학회논문지
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• 제16권11호
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• pp.11-19
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• 2016

생체인식기술 발달과 그 활용범위가 점차 확장하는 상황에서 이에 대해 사용자 입장에 중심을 둔 사용의도에 대한 연구는 매우 미미한 실정이다. 본 연구는 생체인식기술 종류에 따라 사용자가 인식하는 자기 효능감, 신뢰성, 보안성, 안전성, 편의성에 대해 살펴보고 각 인증수단에 대한 인식 차이가 향후 해당 생체인식기술 사용의도와 어떤 관련이 있는지 알아보고자 하였다. 인지된 자기 효능감, 신뢰성, 보안성, 안전성, 편의성을 독립변수로, 사용의도를 종속변수로 하여 각 생체인증 수단별로 종속변수에 미치는 독립변인 효과를 분석한 결과 지문인식의 경우 인지된 신뢰성과 편의성이 향후 지속사용의도에 유의미한 영향을 주고, 홍채인식은 인지된 편의성이, 정맥인식의 경우 인지된 신뢰성이 각 생체인식수단 사용의도에 가장 큰 영향을 주는 요인으로 나타났다. 이와 같은 연구결과는 향후 다양한 분야에서 생체인식 기술을 도입하는 과정에 사용자 인식이 고려된 적용 방향을 제시할 수 있을 것이다.

• Journal of Forest and Environmental Science
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• 제33권2호
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• pp.113-121
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• 2017

In flight particulate matter particularly emissions generated by incomplete combustion processes has become a subject of global concern due to the health problems and environmental impacts associated with them. This has compelled most countries to set standards for coarse and fine particles due to their conspicuous impacts on environment and public health. This contribution therefore explores forest fire emissions and how its particulates affects air quality, damage to vegetation, water bodies and biological functions as architects for lung diseases and other degenerative illnesses such as oxidative stress and aging. Soot was collected from simulated forest fire using a clean glass surface and carefully transferred into amber vials for analysis. Volatile components of soot were collected over 10 mL dichloromethane and analyzed using a QTOF Premier-Water Corp Liquid Chromatography hyphenated to a mass selective detector (MSD), and Gas Chromatograph coupled to a mass spectrometer (GC-MS). To characterize the size and surface morphology of soot, a scanning electron microscope (SEM) was used. The characterization of molecular volatiles from simulated forest fire emissions revealed long chain compounds including octadec-9-enoic acid, octadec-6-enoic acid, cyclotetracosane, cyclotetradecane, and a few aromatic hydrocarbons (benzene and naphthalene). Special classes of organics (dibenzo-p-dioxin and 2H-benzopyran) were also detected as minor products. Dibenzo-p-dioxin for instance in chlorinated form is one of the deadliest environmental organic toxins. The average particulate size of emissions using SEM was found to be $11.51{\pm}4.91{\mu}m$. This study has shown that most of the emissions from simulated forest fire fall within $PM_{10}$ particulate size. The molecular by-products of forest fire and particulate emissions may be toxic to both human and natural ecosystems, and are possible precursors for various respiratory ailments and cancers. The burning of a forest by natural disasters or man-made fires results in the destruction of natural habitats and serious air pollution.

• 전기전자학회논문지
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• 제23권4호
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• pp.1328-1336
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• 2019

안전하고 최적의 배터리 성능을 유지하기 위해 정확한 충전상태(SOC) 추정 기술이 필수적이다. 본 논문에서는 기존의 전류적산 방법이 가지고 있는 문제를 해결하기 위해 시간 종속성을 가지는 인공지능 기반의 LSTM을 이용한 SOC 추정 방법을 적용하였다. 훈련과 검증에 필요한 데이터는 전기적 실험을 통해 일정 크기로 방전된 전류, 전압, 온도를 수집하였고 학습을 위한 입력데이터의 질을 향상시키기 위해 데이터 전처리를 수행하였다. 또한, LSTM 모델의 구조 및 하이퍼파라미터 설정에 따른 학습 능력과 SOC 추정 성능을 비교하였다. 학습한 모델은 UDDS 프로파일을 통해 검증하였으며, RMSE 0.82%, MAX 2.54%의 추정 정확도를 달성하였다.

• 대한족부족관절학회지
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• 제18권4호
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• pp.195-201
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• 2014

Purpose: The purpose of this study is to develop guidelines for clinical trial of the total ankle replacement system for premarket approval. Materials and Methods: We selected and analyzed nine peer-reviewed articles whose quality had been proven in a previous phase. Two investigators extracted parameters for guideline criteria, including number of cases, patient age, follow-up period, failure rate, radiographic osteolysis rate, residual pain rate, and percentage of satisfaction. In addition, the inclusion and exclusion criteria were analyzed and developed. Results: Eight level IV studies and one level II study were included. The average number of cases was 159 cases and the mean patient age was 63.5 years. The mean follow-up period was 4.2 years, ranging from two to nine. The average failure rate of total ankle replacement in mid- to long-term follow-up was approximately 13% (2%~32.3%). The rate of osteolysis was approximately 18%. Residual pain was common (21.4%~46%), but overall patient satisfaction was approximately 85.6% (67.5%~97%). Conclusion: The results could be used as criteria for designing the clinical studies, such as number of cases, patient age (over 60 years), and follow-up period (minimum two years). The clinical scoring system and 36-item short form health survey (SF-36) was the most commonly used method for clinical evaluation for total ankle arthroplasty. In addition, the overall results, including failure rate, osteolysis rate, and patient satisfaction, could be used as a parameter of guidelines for premarket approval.

• 한국해양공학회지
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• 제34권5호
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• pp.285-293
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• 2020

This study evaluated the Hook-up installation of an offshore site construction process, which is the final step in an offshore site installation process. During Hook-up installation, the offshore structure can have a detrimental effect on the work stability due to low-frequency motion. Moreover, economic costs can be incurred by the increase in available days of a tugboat. Therefore, this study developed a numerical analysis program to assess the dynamic behavior of mooring systems during hook-up installation to analyze the generally performed installation process and determine when the tugboat should be released. In this program, the behavior of an offshore structure was calculated using Cummin's time-domain motion equation, and the mooring system was calculated by Lumped mass method (LMM). In addition, a tugboat algorithm for hook-up installation was developed to apply the Hook-up procedure. The model used in the calculations was the barge type assuming FPSO (Floating production storage and off-loading) and has a taut mooring system connected to 16 mooring lines. The results of the simulation were verified by comparing with both MOSES, which is a commercial program, and a calculation method for restoring coefficient matrix, which was introduced by Patel and Lynch (1982). Finally, the offset of the structure according to the number of tugboats was calculated using the hook-up simulation, and the significant value was used to represent the calculation result.