• The Journal of Advanced Prosthodontics
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• 제11권6호
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• pp.350-357
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• 2019

PURPOSE. This study aims to evaluate the loosening torque on the implant fixture, and to assess the accuracy of difference electronic torque drivers. MATERIALS AND METHODS. Three electronic torque drivers were used to measure the loosening torque on the implant system (AnyOne; MegaGen). The implant fixtures were divided among the 3 electronic torque driver types (W&H, SAESHIN, and NSK group) and 9 for each group. The screws were fastened at the implant fixture by three electronic torque drivers using the tightening torques recommended by the manufacturers of the drivers. After 10 minutes, the screws were again fastened at the implant fixture with equal torque. Then, the loosening torques were measured with an MGT12 torque gauge (MARK-10, Inc.). This measurement procedure was repeated 10 times under loosening torques of 15 Ncm, 25 Ncm, and 35 Ncm. In the statistical analysis, all values of loosening torque were analyzed with the one-way ANOVA and Kruskal-Wallis test (α=.05) for comparative evaluation. RESULTS. There were significant inter-group differences at loosening torques of 15 Ncm and 25 Ncm (P<.05). The accuracy of the NSK driver was the highest, followed by SAESHIN and W&H. There was no significant difference between NSK and W&H at 35 Ncm (P>.05). The SAESHIN driver showed the closest loosening torque at 35 Ncm. CONCLUSION. The most accurate loosening torques were SAESHIN at 35 Ncm, and NSK at 15 Ncm and 25 Ncm. Since the loosening torque may vary depending on the tightening torques and electronic torque drivers, periodic calibration of the electronic torque driver is recommended.

• 대한의용생체공학회:의공학회지
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• 제43권6호
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• pp.375-381
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• 2022

Brain-computer interface (BCI) is a technology that allows users with motor disturbance to control machines by brainwaves without a physical controller. Motor imagery (MI)-BCI is one of the popular BCI techniques, but it needs a long calibration time for users to perform a mental task that causes high fatigue to the users. MI is reported as showing a similar neural mechanism as motor execution (ME) and motor observation (MO). However, integrative investigations of these three tasks are rarely conducted. In this study, we propose a new paradigm that incorporates three tasks (MI, ME, and MO) and conducted a comparative analysis. For this study, we collected Electroencephalograms (EEG) of motor imagery/execution/observation from 28 healthy subjects and investigated alpha event-related (de)synchronization (ERD/ERS) and classification accuracy (left vs. right motor tasks). As result, we observed ERD and ERS in MI, MO and ME although the timing is different across tasks. In addition, the MI showed strong ERD on the contralateral hemisphere, while the MO showed strong ERD on the ipsilateral side. In the classification analysis using a Riemannian geometry-based classifier, we obtained classification accuracies as MO (66.34%), MI (60.06%) and ME (58.57%). We conclude that there are similarities and differences in fundamental neural mechanisms across the three motor tasks and that these results could be used to advance the current MI-BCI further by incorporating data from ME and MO.

• 분석과학
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• 제20권5호
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• pp.400-405
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• 2007

액체크로마토그래피/질량분석법(LC/MS) 및 핵자기공명분광분석법 $^1H(NMR)$을 이용하여 화장품에 들어있는 글리세린을 동시 비교분석하였다. 화장품 시료를 물에 용해시키고 수산화나트륨을 첨가하여 시료용액을 강알칼리 상태로 유지시킨 후, 시료용액 중의 글리세린을 benzoyl chloride로 유도체화 반응 시키고 유도체화된 글리세린을 pentane으로 추출하여 LC/MS로 정량분석 하였다. $^1H$ NMR 분석은 시료를 전처리 없이 $D_2O$ 용매에 직접 용해시키고, 글리세린을 ERETIC(Electronic REference To access In vivo Concentrations) 방법을 이용하여 $^1H$ NMR로 직접 정량분석 하였다. LC/MS 및 NMR 분석결과 LC/MS의 검량선은 $0.1-10{\mu}g/mL$ 농도범위에서 $r^2=0.9991$ 이었고 $^1H$ NMR의 검량선은 $25-500{\mu}g/mL$ 농도범위에서 $r^2=1$의 상관계수를 갖는 좋은 직선성을 얻었다.

• 천문학논총
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• 제32권1호
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• pp.21-23
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• 2017

We present a comparative study of CO and polycyclic aromatic hydrocarbon (PAH) emission toward a region including the massive star-forming regions of NGC 6334 and NGC 6357. We use the NANTEN $^{12}CO(J=1-0)$ data and the AKARI $9{\mu}m$ All-Sky diffuse map in order to evaluate the calibration accuracy of the AKARI data. We confirm that the overall CO distribution shows a good spatial correspondence with the PAH emission, and their intensities exhibit a good power-law correlation with a spatial resolution down to 4' over the region of $10^{\circ}{\times}10^{\circ}$. We also reveal poorer correlation for small scale structures between the two quantities toward NGC 6357, due to strong UV radiation from local sources. Larger scatter in the correlation toward NGC 6357 indicates higher ionization degree and/or PAH excitation than that of NGC 6334.

• 한국농공학회논문집
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• 제47권3호
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• pp.3-13
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• 2005

The conceptual rainfall-runoff models are used to predict complex hydrological effects of a basin. However, to obtain reliable results, there are some difficulties and problems in choosing optimum model, calibrating, and verifying the chosen model suitable for hydrological characteristics of the basin. In this study, Genetic Algorithm and SCE-UA method as global optimization methods were applied to compare the each optimization technique and to analyze the application for the rainfall-runoff models. Modified TANK model that is used to calculate outflow for watershed management and reservoir operation etc. was optimized as a long term rainfall-runoff model. And storage-function model that is used to predict real-time flood using historical data was optimized as a short term rainfall-runoff model. The optimized models were applied to simulate runoff on Pyeongchang-river watershed and Bocheong-stream watershed in 2001 and 2002. In the historical data study, the Genetic Algorithm and the SCE-UA method showed consistently good results considering statistical values compared with observed data.

• 중환자간호학회지
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• 제8권1호
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• pp.71-79
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• 2015

Purpose: The purpose of this study was to compare the applicability of the Charlson Comorbidity Index (CCI) and Acute Physiology, Age, Chronic Health Evaluation III (APACHE III) to the prediction of the healthcare outcomes of intensive care unit (ICU) patients. Methods: This research was performed with 136 adult patients (age>18 years) who were admitted to the ICU between May and June 2012. Data were measured using the CCI score with a comorbidity index of 19 and the APACHE III score on the standard of the worst result with vital signs and laboratory results. Discrimination was evaluated using receiver operating characteristic (ROC) curves and area under an ROC curve (AUC). Calibration was performed using logistic regression. Results: The overall mortality was 25.7%. The mean CCI and APACHE III scores for survivors were found to be significantly lower than those of non-survivors. The AUC was 0.835 for the APACHE III score and remained high, at 0.688, for the CCI score. The rate of concordance according to the CCI and the APACHE III score was 69.1%. Conclusion: The route of admission, days in ICU, CCI, and APACHE III score are associated with an increased mortality risk in ICU patients.

• 반도체디스플레이기술학회지
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• 제16권3호
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• pp.8-13
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• 2017

In this paper, the measurement of the inner diameter dimension of the circular hole by using a machine vision system was studied. This paper was focused on the theory and key technologies of machine vision inspection technology for the improvement of measurement accuracy and speed of the micro circular holes. A new method was proposed and was verified through the experiments on Gray conversion, binarization, edge extraction and Hough transform in machine vision system processes. Firstly, the Hough transform was proposed in order to improve the speed increase and implementation ease, it demonstrated the superiority of Hough transform and improvement through a comparative experiment. Secondly, we propose a calibration method of the system in order to obtain exactly the inner diameter of the circular hole. Finally, we demonstrate the reliability of the entire system as a MATLAB-based implementation of the GUI program, measuring the inner diameter of the circular hole through the circular holes of different dimensions measuring experiment.

• 웰빙융합연구
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• 제5권3호
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• pp.27-41
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• 2022

Purpose: In this study, pollutants generated in industrial areas were measured using a Portable Air Quality Measurement System(PAQMS). This study intends to examine in detail improvement measures and operational capabilities to operate a more efficient PAQMS. Research design, data and methodology: This study compares and analyzes the measurement values of the PAQMS and the measurement values of the national air quality measurement network. It is intended to develop a PAQMS corresponding to the data of the national measurement network by minimizing the errors that occur during comparative measurement and analysis and supplementing and improving the problems that occur during the current equipment calibration. Results: A PAQMS is an essential equipment for faster and more accurate measurement and analysis of pollutants in case of untimely measurement and civil complaints due to Micro Climate(local weather and environmental influences). Currently, there are many atmospheric measurement equipment in Korea, but only equipment for each item is produced and sold. Currently, these devices on the market must satisfy various conditions such as stable power, temperature, and humidity to calculate accurate measurement values. Conclusions: Therefore, there is no equipment that satisfies the conditions for performing detailed measurement in the field where accurate measurement is required. In this study, these field work conditions and contents for stable measurement were mentioned in the text.

• 신재생에너지
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• 제20권2호
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• pp.17-25
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• 2024

In this study, the effect of the time step specified in a computational fluid dynamics (CFD) simulation on load response is analyzed and the drag coefficients of the floating body of floating offshore wind turbines (FOWTs) are estimated. By evaluating the error in the FOWT load response and the change in the drag-coefficient values based on the density of the time intervals, this study aims to establish a time-interval setting that minimizes the time and cost of CFD simulations for selecting drag-coefficient values. Practical CFD utilization strategies necessary for the calibration of medium-to high-fidelity analysis tools are presented. Based on a comparative analysis of CFD simulations conducted at various time intervals, the results confirmed that under a certain time interval that sufficiently considers various factors, the accuracy of the FOWT response with respect to density shows minimal differences, thereby providing an efficient utilization method for CFD simulations in FOWT design and analysis.

• 한국의학물리학회지:의학물리
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• 제24권4호
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• pp.253-258
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• 2013

본 연구의 목적은 electronic portal imaging device (EPID)를 통하여 방사선 치료를 받는 환자로부터 투과해 나오는 선량으로 외부적인 선량 재구성과 몬테카를로 전산모사로부터 도출되는 내부 선량 계측과의 관계를 도출하고 이를 분석하기 위한 연구로 진행되었다. 본 연구는 전산모사 연구로써 두 가지의 경우를 비교 분석하고 이와 비슷한 연구에 대한 기본적인 지표를 제공하고자 시행되었다. 실험에 관한 기하학적 정보와 방사선 소스에 대한 정보를 몬테카를로 전산모사 툴인 Monte Carlo n-particle (MCNPX)에 입력하였고 EPID 이미지 도출을 위하여 MCNPX 내에 tally카드를 이용하여 선량정보를 도출하고 이를 영상화 할 수 있도록 하였다. 또한 내부적인 계측을 위하여 물 팬텀을 소스와 표면의 거리(source to surface distance, SSD)가 100 cm이 되도록 설정하였으며, 그보다 10 cm 아래에 EPID를 위치시켰다. 내부 계측은 물팬텀 자체에서 흡수되는 흡수 선량을 mesh tally로 수집하였고, 4문 조사를 통하여 중첩된 선량에 대한 데이터를 획득하였다. 그와 동시에 EPID에서 물을 투과해 나오는 선량을 획득 한 뒤 역 투사 방법을 사용하여 선량 재구성을 하였다. 이둘의 경우를 비교하기 위해 자체적인 교정(calibration)을 통하여 투과해 나온 선량과 흡수된 선량과의 관계를 비교하고 4문 조사를 통하여 물 팬텀 내의 특정 부분에 대한 중첩된 선량 데이터와 EPID를 통해 재구성한 선량 데이터를 분석하였다. 물 팬텀과 EPID에서 획득한 누적 선량의 합은 각각 평균 3.4580 MeV/g과 3.4354 MeV/g이었다. 이는 앞서 계측된 물 팬텀 내부의 누적 선량과 0.6536% 선량 오차를 보였다.