• Korean Journal of Radiology
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• 제22권5호
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• pp.735-741
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• 2021

Objective: To evaluate circularity as a quantitative shape factor of small renal tumor on computed tomography (CT) in differentiating fat-poor angiomyolipoma (AML) from renal cell carcinoma (RCC). Materials and Methods: In 257 consecutive patients, 257 pathologically confirmed renal tumors (either AML or RCC less than 4 cm), which did not include visible fat on unenhanced CT, were retrospectively evaluated. A radiologist drew the tumor margin to measure the perimeter and area in all the contrast-enhanced axial CT images. In each image, a quantitative shape factor, circularity, was calculated using the following equation: 4 x π x (area ÷ perimeter²). The median circularity (circularity index) was adopted as a representative value in each tumor. The circularity index was compared between fat-poor AML and RCC, and the receiver operating characteristic (ROC) curve analysis was performed. Univariable and multivariable binary logistic regression analysis was performed to determine the independent predictor of fat-poor AML. Results: Of the 257 tumors, 26 were AMLs and 231 were RCCs (184 clear cell RCCs, 25 papillary RCCs, and 22 chromophobe RCCs). The mean circularity index of AML was significantly lower than that of RCC (0.86 ± 0.04 vs. 0.93 ± 0.02, p < 0.001). The mean circularity index was not different between the subtypes of RCCs (0.93 ± 0.02, 0.92 ± 0.02, and 0.92 ± 0.02 for clear cell, papillary, and chromophobe RCCs, respectively, p = 0.210). The area under the ROC curve of circularity index was 0.924 for differentiating fat-poor AML from RCC. The sensitivity and specificity were 88.5% and 90.9%, respectively (cut-off, 0.90). Lower circularity index (≤ 0.9) was an independent predictor (odds ratio, 41.0; p < 0.001) for predicting fat-poor AML on multivariable logistic regression analysis. Conclusion: Circularity is a useful quantitative shape factor of small renal tumor for differentiating fat-poor AML from RCC.

• 한국공작기계학회논문집
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• 제11권2호
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• pp.24-29
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• 2002

A study for the circularity of machine tool is classified into two ways. One is to measure the circularity of machine tool by a existing measuring device. The other is to measure the circularity by remodeling the existing measuring device. We will improve on measurement of circularity using circular test method by a two-dimensional probe and a master ring for machining tools and investigate influence of trigger method, acceleration data sampling.

• 자원리싸이클링
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• 제31권6호
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• pp.66-72
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• 2022

국내산 인상흑연정광의 리튬이온전지 소재로서 활용을 위해 고강도 혼합기를 이용하여 구형화 실험 후 건식분급을 진행하여 각 산물에 대한 구형화도와 입도를 분석하였다. 3,000 rpm의 로터속도에서는 정광시료와 산물의 입도와 구형화도의 차이가 관찰되지 않았으나, 로터속도를 6,000 rpm, 10,000 rpm 12,000 rpm으로 조절하여 구형화도 실험을 진행한 결과, 로터속도와 구동시간의 증가에 따라 구형화도는 증가하고 입도는 감소하였다. 로터속도 12,000 rpm에서 10분간 구동한 결과, 구형화도는 0.870으로부터 0.936까지 증가하였다. 구형화실험 후 건식분급을 진행하였을 때 조립자의 구형화도는 0.947까지 증가하였고 SEM 결과에서 구형입자가 확인되어 구형화가 성공적으로 이루어졌다고 판단되었다.

• 한국세라믹학회지
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• 제39권8호
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• pp.735-741
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• 2002

미분탄 화력발전소에서 보일러의 부하를 변화시켰을 때 전기집진기에서 단별 채취한 fly ash에 대해서 디지털 이미지 분석을 이용하여 원형지수를 검토하였다. 원형지수 측정은 다음과 같은 다섯 단계, 즉 ① 이미지 획득, ② 이미지 전처리, ③ 검출, ④ 이미지 후처리, ⑤ 측정의 단계를 거쳐 이루어 졌다. Fly ash의 평균 원형지수는 0.78∼0.83의 범위를 나타냈으며, 같은 위치에 있는 호파에서 채취한 fly ash는 보일러의 부하에 관계없이 유사한 원형지수 값을 나타냈다. 그리고 첫 번째 호파에서 세 번째 호파로 갈수록, 즉 fly ash의 평균 입경이 작아질수록 원형지수는 증가하는 경향을 나타냈다.

• 한국정보통신학회논문지
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• 제8권1호
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• pp.185-191
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• 2004

본 논문은 컴퓨터 그래픽에서 주요 이슈중 하나인 의류 착장시스템 구현을 위하여 직물의 가장 큰 특성중의 하나인 드레이프성 측정에 관한 연구이다. 가장 최적의 직물의 드레이프성을 구하기 위해 거리함수를 이용하여 볼록점을 계산한 후 직물의 둘레 및 면적, 볼록점 사이의 최대 최소 점과 평균거리와 같은 정보를 구하였다. 그리고 직물의 드레이프성을 나타내는 척도로 직물의 둘레와 면적을 기준으로 원형도를 구하였다. 실험결과 원형도가 직물의 드레이프성을 나타내는 여러 특성치 중 가장 좋은 결과를 보였다. 측정된 직물의 드레이프성은 의류 착장시스템 개발에 기여할 것이다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2003년도 추계종합학술대회 논문집
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• pp.338-342
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• 2003

원형함수를 사용하여 퍼지구를 정의하고 원형함수의 수렴을 이용하여 퍼지구의 수렴성을 측정하며 하나의 퍼지구는 특정한 일반 구로 수렴함을 보인다.

• 한국공작기계학회논문집
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• 제11권5호
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• pp.15-22
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• 2002

A study is the selection of optimum forming condition for RP system. We develop the Automatic design program for machine element using visual LISP program in AutoCAD. Automatic design program reduces the required time for feedback between design and manufacturing of workpiece. Also we investigate the relationship between circularity of 3D solid model and circularity of rapid prototype using RP system and we will find optimum forming condition in RP system.

• Bulletin of the Korean Chemical Society
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• 제16권12호
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• pp.1173-1176
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• 1995

The explicit results of the degrees of circularity for various kinds of completely polarized light in a nonpolar fluid composed of chiral molecules are obtained with the aid of the Ornstein-Zernike form for the correlation function of density fluctuations. Then, the results are in detail discussed in two limiting cases of critical region and compared with circular intensity differences.

• 한국실내디자인학회논문집
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• 제17권6호
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• pp.111-119
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• 2008

This thesis is to make it clear that simulacre concept of is an important factor that provides the motive to make spaces and to make it clear that yard in Korean traditional architecture has more meaning of a container that contains the simulacres of life than formal aspects. Namely, focusing on the simulacres, among existing important factors that cause changes in architectural spaces such as structure, function, beauty, I shall make it clear that simulacre concept, which is a creation thinking of post-structuralism philosopher, Deleuze, is a logic that builds and changes spaces. Also, the purpose of this research is to investigate successive circularity of yard spaces with the mutual relationship between simulacre concept that has virtual multiplicity and yard in Korean traditional architecture, a space of infinite emptiness. When certain simulacres occur in the yard, the ambivalence of simulacres provides meanings to yard by affiliating numerous simulacre factors, then by combination among those meanings, yard get mutual dependence. This is an important core point that I have focused on the beginning of this research. This research has found out the successive circularity of yard based on the relationship between simulacres and the essence of yard. The meaning of this research is to have found out that yard has the meaning of "a bowl that contains the simulacres of life," going over the simple meaning as a space between door and fence. Also, the simulacre concept is thought to be discussed as a motive for creation of various spaces from now on.

• 대한건축학회연합논문집
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• 제20권6호
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• pp.9-16
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• 2018

The purpose of this research was influenced by the historical background of Japanese modern architecture by the circulation of Kuma Kengo's architectural works and he wanted to look at the values and directions he was pursuing and how they were expressed in his works. The results of the review are summarized as follows. First, metabolism was developed as a reaction of modernism in modern architecture, focusing on growth through infinite reproduction by looking at architecture and cities as organisms and by using unit space as cells. Kuma Kengo, on the other hand, argues that focusing on the possibility of decimation of unit members by sequencing the elements that make up the space smaller than the unit space is closer to an ecological architecture. Second, what Kuma Kengo says is "erase the architecture" that is naturally related to the environment and disappears when its use is exhausted. His argument is expressed in individual architectural works through 'visual erase', 'particle painting of materials' and 'independence through dependency.' Through this, Kuma Kengo's ecological architectural languages were influenced by the ecological causes of metabolism, but they differed from the perspective of seeing architectural circulation as an organism. If metabolism was intended to realize circulation with growth potential based on the module of unit space, Kuma Kengo sought to implement circulation with the extinction of the unit members of space.