• Korean Journal of Radiology
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• v.22 no.5
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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.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.2
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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.

• Resources Recycling
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• v.31 no.6
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• pp.66-72
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• 2022

The circularity and particle size distribution of products obtained from dry classification after circularity tests using a high-intensity mixer were investigated to evaluate the use of domestic graphite concentrate as a lithium-ion battery material. At a rotor speed of 3,000 rpm, the particle size and circularity of the concentrated sample and product were unchanged. The circularity increased and particle size decreased when the rotor speeds were increased to 6,000 rpm, 10,000 rpm, and 12,000 rpm and the operating time was increased. For instance, the circularity increased from 0.870 to 0.936 when the rotor speed was increased from 3,000 rpm to 12,000 rpm for an operating time of 10 min. After the circularity test, dry classification was performed, wherein the circularity of the coarse particles was found to have increased to 0.947. Round particles were observed in the SEM images, indicating that high circularity was successfully achieved.

• Journal of the Korean Ceramic Society
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• v.39 no.8
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• pp.735-741
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• 2002

This paper investigates circularity of fly ashes using the digital image processing. Fly ashes directly collect from electrostatic precipitator when the load of conditions of boiler are changed at a coal-fired power plant. Circularity measurement can be accomplished in five steps: ① image acquisition, ② grey image processing, ③ detection the component to measure ④ binary image processing ⑤ feature measurement. The mean circularity of fly ashes is in the range of 0.78 to 0.83. fly ashes collected from the same hopper has similar circularity regardless of the load of boiler and circularity increases as going from the 1st hopper to 3rd one, namely as particle size become finer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.185-191
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• 2004

This article is concerned with cloth wearing system issues arising in the computer graphics. In particular, we study the issues of fabric drape properties for representing cloth wearing system. The convex points based on distance function are calculated to represent useful fabric drape properties. The information such as perimeter area, max and min point among convex point, the average distance between convex points are extracted. A strategy of a circularity based on the perimeter and area is considered for fabric drape property measurement. By experimental result, the circularity is most powerful factor to represent the drape property among the several characteristics. The measured drape properties will contribute to cloth wearing system development.

• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.338-342
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• 2003

The concept of a circularity function is used in defining fuzzy spheres The circularity function of a fuzzy sphere converses to one of crisp sphere as the fuzzy sphere shapes itself more and more like a crisp sphere.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.5
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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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• v.16 no.12
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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.

• Korean Institute of Interior Design Journal
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• v.17 no.6
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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.

• Journal of the Regional Association of Architectural Institute of Korea
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• v.20 no.6
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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.