• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2009년도 추계학술발표대회
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• pp.345-346
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• 2009

The segmentation of vessel including portal vein, hepatic vein and artery, from Computed Tomography (CT) images plays an important role in the therapeutic strategies for hepatic diseases. Representing segmented vessels in three dimensional spaces is extremely useful for doctors to plan liver surgery. In this paper, proposed method is focused on smoothing technique of segmented 3D liver vessels, which derived from 3D region growing approach. A pixel expand algorithm has been developed first to avoid vessel lose and disconnection cased by the next smoothing technique. And then a binary volume filtering technique has been implemented and applied to make the segmented binary vessel volume qualitatively smoother. This strategy uses an iterative relaxation process to extract isosurfaces from binary volumes while retaining anatomical structure and important features in the volume. Hard and irregular place in volume image has been eliminated as shown in the result part, which also demonstrated that proposed method is a suitable smoothing solution for post processing of fine vessel segmentation.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.650-651
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• 2006

This paper presents a study of large grains by transmission electron microscopy in two WC-Co alloys, one W rich and one C rich. In the W rich alloy, some large grains are found in contact with the $\eta$ phase. The C content influences the morphology of large grains: they are flatter in the C rich alloy with smoother interfaces. Whatever the C content, they contain few dislocations compared to matrix grains except often in a small area. Small WC grains are often found inside the large grains. They have likely been engulfed during the growth of the large grains owing to the low boundary energy.

• Communications for Statistical Applications and Methods
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• 제30권3호
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• pp.311-330
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• 2023

The present work describes simulation studies to compare the performances in terms of averaged mean squared error of bayesian wavelet shrinkage methods in estimating component curves from aggregated functional data. Five bayesian methods available in the literature were considered to be compared in the studies: The shrinkage rule under logistic prior, shrinkage rule under beta prior, large posterior mode (LPM) method, amplitude-scale invariant Bayes estimator (ABE) and Bayesian adaptive multiresolution smoother (BAMS). The so called Donoho-Johnstone test functions, logit and SpaHet functions were considered as component functions and the scenarios were defined according to different values of sample size and signal to noise ratio in the datasets. It was observed that the signal to noise ratio of the data had impact on the performances of the methods. An application of the methodology and the results to the tecator dataset is also done.

• International journal of advanced smart convergence
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• 제12권2호
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• pp.90-95
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• 2023

With the rapid development of deep learning and artificial intelligence, generative models have achieved remarkable success in the field of image generation. By combining the stable diffusion method with Web UI technology, a novel solution is provided for the application of AI painting generation. The application prospects of this technology are very broad and can be applied to multiple fields, such as digital art, concept design, game development, and more. Furthermore, the platform based on Web UI facilitates user operations, making the technology more easily applicable to practical scenarios. This paper introduces the basic principles of Stable Diffusion Web UI technology. This technique utilizes the stability of diffusion processes to improve the output quality of generative models. By gradually introducing noise during the generation process, the model can generate smoother and more coherent images. Additionally, the analysis of different model types and applications within Stable Diffusion Web UI provides creators with a more comprehensive understanding, offering valuable insights for fields such as artistic creation and design.

• 한국정밀공학회지
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• 제10권3호
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• pp.87-96
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• 1993

In this study, the peak stress of a fuillet in elastic structure was optimized to have minimum value by using quadratic isoparametric element. The method of auomatic gridding was also developed along with shape algorithm and design element technique was adopted in selecting design variables. The computer program developed was combined with the Hooke-Jeeves direct algorithm of optimization techniques in order to minimize the peak stress of the fillet. The imployment of design element technique significantly cut down computer time by the reduction in design variables, and the opitmum fillet shape with uniform minimum stress was obtained by varying design variables along x and y directions in improving the shape compared to other results. By using automatic gridding, in which Bezier surfaces and Coons surfaces of cubic interpolation were employed, the irregular boundary was removed resulting in smoother anbd more accurate fillet shape possessing uniform minimum stress.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3599-3616
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• 2023

After a nuclear power plant (NPP) accident, it would be helpful to predict the movement of the radioactive plume emitted from the NPP as accurately as possible to protect the nearby population. Radioactive plumes are mainly affected by wind direction and speed. Since it is difficult to identify the wind direction and speed immediately after the accident, a good understanding of the historical wind data could save many lives and ensure smoother evacuation procedures. In this study, wind data for the past 10 years are analyzed for the five NPPs in the Republic of Korea (ROK). The analyzed data include wind direction and wind speed from 2012 to 2021. In particular, the characteristics of the wind field blowing from the NPPs to the nearest densely populated regions are examined. Finally, suggestions to improve evacuation plans are made.

• International Journal of Advanced Culture Technology
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• 제12권2호
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• pp.98-103
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• 2024

This paper revisits politeness expressions in English, exploring their linguistic characteristics and the underlying social dynamics they reflect. Grounded in pragmatic theories, politeness is examined as a phenomenon shaped by societal norms, wherein language users navigate the delicate balance between efficiency and maintaining positive social interactions. Through an analysis of various linguistic devices such as modal auxiliary verbs, progressive and past tenses, depersonalization, and the use of hedges, the study elucidates how speakers endeavor to mitigate potential burdens on listeners and foster smoother communication. By understanding and employing these linguistic strategies, English learners can better navigate the nuances of politeness expressions in the English cultural context. This exploration underscores the pivotal role of politeness in interpersonal communication and highlights its significance in facilitating effective interaction among language users.

• 한국항공우주학회지
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• 제43권12호
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• pp.1062-1070
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• 2015

본 연구에서는 최적 스무딩 필터를 이용한 이동 목표물 궤적 추정을 수행한다. 이동 목표물의 위치와 속도 데이터 확보를 위해 마이크로폰 어레이를 이용한 빔형성 기법이 적용하며, 획득 데이터를 이용한 궤적 추정 성능 향상을 위해 칼만 필터와 최적 스무딩 필터를 설계한다. 목표물의 기동을 고려한 싱어 표적 모델을 필터에 활용한다. 최적 스무딩 필터 검증을 위해 초기 기동을 하는 미사일 시뮬레이션 환경에서 추정 성능을 확인하였으며, 모형 로켓을 이용한 실험을 통해 빔형성 기법과 칼만 필터, 그리고 최적 스무딩 필터의 궤적 추정 성능을 검증하였다. 검증 결과 적용한 필터를 통해 빔형성 기법을 이용한 궤적 추정 성능의 향상을 확인하였으며, 칼만 필터와 비교해 최적 스무딩 필터의 이동 목표물 궤적 추정 정밀도가 향상됨을 확인하였다.

• 대한치과보철학회지
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• 제37권1호
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• pp.51-70
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• 1999

Dental porcelain is one of the materials of choice for restoration where esthetics is of concern, but has a considerable potentials of wear. The wear of enamel is variable when opposed by different porcelain systems and surface conditions, and the exposed dentine and opaque porcelain due to clinical failure is expected to have high potentials of wear. The purpose of this study was to investigate the wear effects of self-glazed, polished incisal porcelain. polished dentine and opaque porcelain against human enamel in the laboratory by use of a pin-on-disk type wear tester. 4 types of dental porcelain($Vita-{\Omega}$, Ceramco-II, Vintage powder $Vita-{\alpha}$ of In-Ceram system) and type IV gold alloy as cotrol group were used for test specimens. Intact buccal cusps of maxillary premolar were used for enamel specimens, and the cusp converged to a point and was devoid of visible abrasion, caries, decalcification. The upper part was the cusp of a maxillary premolar and the lower part was a porcelain specimen. The enamel wear was deter-mined by weighing the cusp before and after each test. Surface profilometer was used to quantitate wear of the porcelain specimens. Vicker's hardness tester was used to evaluate the surface hardness of test specimens. The SEM was used to evaluate the wear surfaces. The results were as follows : 1 Self-glazed porcelain produced more enamel wear than polished porcelain, especially the enamel wear of $Vita-{\alpha}$ self-glazed porcelain was 3.2 times more than that of other groups. 2. Opaque porcelain produced least porcelain wear, $Vita-{\alpha}$ self-glazed porcelain produce greatest porcelain wear, but there was no statistically significant difference between the groups(p>0.05). 3. The enamel wear of dentine porcelain was 3.8 times more than that of polished inisal porcelain(p<0.05), and the enamel wear of opaque porcelain was 1.9 times more than that of polished inisal porcelain, but there was no statistically significant difference between the groups(p>0.05) 4. Overglazed porcelain produced less enamel wear than self-glazed porcelain, and more enamel wear than polished porcelain, but there was no statistically significant difference between the groups(P>0.05). 5. The hardness number of $Vita-{\Omega}$ dentine and Ceramco-II opaque porcelain was larger, but that of Vintage dentine and $Vita-{\alpha}$ self-glazed porcelain was similar to other groups. 6. Examination of SEM photographs revealed that overglazed porcelain had smoother surface than self-glazed porcelain, and self-glazed porcelain had smoother surface than polished porcelain. Much polishing scratches and larger porosities were observed on the opaque porcelain specimen, and much polishing scratchess and small porosities were observed on the dentine porcelain specimen.

• Journal of Astronomy and Space Sciences
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• 제26권1호
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• pp.75-88
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• 2009

이 연구의 목적은 선형화 과정이 필요 없는 Unscented 변환(Unscented Transformation)을 사용한 후처리 배치 알고리즘을 소개하고, 기존 최소자승법을 이용한 후처리 배치 필터와 반복 UKF 스무더(Iterative Unscented Kalman Filter Smoother)들과 비교하여 추정 방법 간의 성능비교와 장단점을 분석하는 것이다. 연구에 사용된 위성 궤도 결정시스템의 동역학 방정식은 지구의 비대칭 중력장의 영향, 대기항력, 태양복사압 및 달과 태양의 중력으로 구성되었다. 관측 데이터로는 지상국으로부터 측정한 위성의 거리, 방위각과 고도각이 사용되었다. 특히, 비선형성의 영향에 대한 추정 방법 간의 성능과 장단점의 비교를 위해 위성의 포기 궤도오차별, 관측데이터의 관측 잡음의 크기별 테스트를 수행하였다. 이 연구를 통해 소개된, 선형화 과정이 필요 없는 Unscented 변환 기반의 후처리 배치 필터는, 비선형성의 특징이 증대된 상황에서 기존의 후처리 배치 알고리즘들에 비해 초기 궤도오차별, 관측데이터 잡음의 크기별 테스트 시 평균적으로 각각 약 5%와 12%정도의 정밀도 향상결과를 보였다. 또한, 기존 최소자승법을 이용한 후처리 배치필터가 발산한 상황에서도, 수렴성을 확보하는 안정적인 결과를 얻을 수 있었다. 그러므로 Unscented 변환 기반의 후처리 배치필터가 인공위성 궤도 결정 시스템에 효율적으로 사용할 수 있음을 제시하였다.