• ETRI Journal
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• 제43권4호
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• pp.694-701
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• 2021

Catastrophic events cause casualties, damage property, and lead to huge social impacts. To build common standards and facilitate international communications regarding disasters, the relevant authorities in social management rank them in subjectively imposed terms such as direct economic losses and loss of life. Terrorist attacks involving uncertain human factors, which are roughly graded based on the rule of property damage, are even more difficult to interpret and assess. In this paper, we collected 114 183 open-source records of terrorist attacks and used a machine learning method to grade them synthetically in an automatic and objective way. No subjective claims or personal preferences were involved in the grading, and each derived common factor contains the comprehensive and rich information of many variables. Our work presents a new automatic ranking approach and is suitable for a broad range of gradation problems. Furthermore, we can use this model to grade all such attacks globally and visualize them to provide new insights.

• Computers and Concrete
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• 제26권6호
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• pp.505-513
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• 2020

Grading of aggregate influences significantly almost all of the concrete performances. The purpose of this paper is to propose practicable equations that express the optimized total aggregate gradation, by weight or by number of particles in a concrete mix. The principle is based on the fractal feature of the grading of combined aggregate in a solid skeleton of concrete. Therefore, equations are derived based on the so-called fractal dimension of the grain size distribution of aggregates. Obtained model was then applied in such a way a correlation between some properties of the dry concrete mix and the fractal dimension of the aggregate gradation has been built. This demonstrates that the parameter fractal dimension is an efficacious tool to establish a unified model to study the solid phase of concrete in order to design aggregate gradation to meet certain requirements or even to predict some characteristics of the dry concrete mixture.

• Korean Journal of Mathematics
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• 제24권4호
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• pp.663-679
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• 2016

In this paper, we introduce the concepts of several types of interval-valued intuitionistic fuzzy mappings and several types of interval-valued intuitionistic fuzzy compactness in interval-valued intuitionistic smooth topological spaces and then investigate their properties.

• Korean Journal of Mathematics
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• 제14권1호
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• pp.57-64
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• 2006

In this paper, we introduce the concepts of $r$-closure and $r$-interior defined by intuitionistic gradation of openness. We also introduce the concepts of $r$-gp-maps, weakly $r$-gp-maps, and obtain some characterizations in terms of $r$-closure and $r$-interior operators.

• 디지털융복합연구
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• 제16권9호
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• pp.497-502
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• 2018

여성 그레쥬에이션 시술 각도의 변화에 따른 한국남성들의 트렌드 감성별 룩 포지션과의 상관성에 관한 연구로서 시술각도에 따른 여성 그레쥬에이션의 다양한 이미지를 조사하고 이를 바탕으로 창의적인 그레쥬에이션 커트시술이 가능해 지는데 연구 목적이 있다. 설문지법을 사용하여 총 100부의 설문지를 통계분석 하였다. 연구 결과 그레쥬에이션의 시술 각도 $5^{\circ}$, $31^{\circ}$, $85^{\circ}$ 에서는 세련된(sophisticated) 이미지가 나타난다고 응답하였으며 $15^{\circ}$, $65^{\circ}$의 시술 각도에서는 우아한(elegance) 이미지가 나타난다고 응답하였으며 시술 각도 $50^{\circ}$에서는 현대적인(modern) 이미지가 나타난다고 응답하였다. 본 연구를 통해 한국 남성들이 느끼는 트렌드 감성별 룩 포지션에 의하여 세분화 된 여성 그레쥬에이션 커트에 대한 향후 심층적인 후속 연구가 가능해지며 고객만족을 창출과 동시에 보다 심도 깊은 헤어커트 교육의 기초자료로 활용이 가능해지리라 사료된다.

• Steel and Composite Structures
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• 제35권5호
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• pp.671-685
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• 2020

This manuscript presents impacts of gradation of material functions and axial load functions on critical buckling loads and mode shapes of functionally graded (FG) thin and thick beams by using higher order shear deformation theory, for the first time. Volume fractions of metal and ceramic materials are assumed to be distributed through a beam thickness by both sigmoid law and symmetric power functions. Ceramic-metal-ceramic (CMC) and metal-ceramic-metal (MCM) symmetric distributions are proposed relative to mid-plane of the beam structure. The axial compressive load is depicted by constant, linear, and parabolic continuous functions through the axial direction. The equilibrium governing equations are derived by using Hamilton's principles. Numerical differential quadrature method (DQM) is developed to discretize the spatial domain and covert the governing variable coefficients differential equations and boundary conditions to system of algebraic equations. Algebraic equations are formed as a generalized matrix eigenvalue problem, that will be solved to get eigenvalues (buckling loads) and eigenvectors (mode shapes). The proposed model is verified with respectable published work. Numerical results depict influences of gradation function, gradation parameter, axial load function, slenderness ratio and boundary conditions on critical buckling loads and mode-shapes of FG beam structure. It is found that gradation types have different effects on the critical buckling. The proposed model can be effective in analysis and design of structure beam element subject to distributed axial compressive load, such as, spacecraft, nuclear structure, and naval structure.

• 콘크리트학회논문집
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• 제14권4호
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• pp.623-629
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• 2002

최근 환경보존에 대한 인식전환이 범세계적으로 확산되고 있는 가운데 건설기술자들은 환경문제를 해결하기 위한 일환으로 콘크리트에 잔골재를 사용하지 않고 불연속 입도의 굵은 골재를 사용한 환경친화적 건설재료인 다공질콘크리트에 주목하려 다양한 방면에서 연구가 활발히 진행되고 있다. 따라서 본 연구는 환경친화적인 식생용 포러스콘크리트를 제조하기 위한 기초적 연구로서, 골재입도와 페이스트골재비 및 산업부산물의 혼입에 따른 식생용 포러스콘크리트의 물리ㆍ역학적 특성과 식생능력을 평가하였다. 시험결과 골재입도가 감소함에 따라, 페이스트골재비가 증가함에 따라 압축강도는 증가하였으며, 공극률은 점차 감소하였다. 식생능력 평가 결과 씨앗 파종후 30일까지는 골재입도 및 페이스트골재비에 관계없이 동일한 생육양상을 보였으나, 30일 이후에서는 골재입도가 줄어듬에 따라, 페이스트골재비가 증가함에 따라 초장이 감소하였으며, 특히 5~10mm골재를 사용한 경우에는 10~20 mm 20~30mm 입도의 골재를 사용한 경우보다 현저히 초장이 줄어드는 경향이 나타났다.

• 한국도로학회논문집
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• 제18권6호
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• pp.105-113
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• 2016

OBJECTIVES : This study is to develop the optimum mixing proportions for cement concrete pavement with using recycled aggregates. METHODS : The mixture varied recycled coarse aggregates content from 50 % to 100 % to replace the natural coarse aggregates by weight. Tests for fundamental properties as a cement concrete pavement were conducted before and after hardening of the concrete. RESULTS : It was found that the variation in the amount of the recycled aggregate affected the compressive and flexural strength development, as well as the chloride ion penetration resistance. As the amount of the recycled aggregate content increased the compressive and flexural strength and the resistance to chloride ion penetration decreased. However, the resistance to freeze-thaw reaction was affected significantly. In addition, the gradation of the aggregate became worse and hence so did the coarseness factor as the recycled aggregate amount increased. CONCLUSIONS : The fundamental properties of the concrete with recycled aggregate does not seem to be appropriate when the recycled aggregate quality is not guaranteed up to a some level and its replacement ratio is over 50%. The optimized gradation of the aggregates should also be sought when the recycled aggregate is used for the cement concrete pavement materials.

• 한국세라믹학회지
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• 제35권4호
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• pp.378-384
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• 1998

We investigated the possibility of systemizing data for the colour gradation of classical ceramics by build-ing program and D-basing each data information in pottery field that has been fall behind in forming data be-cause of many variable and lacking of data system. In this study we manufactured $CoAl_2O_4$ stain that has stable spinel structure at high temperature and then mixed base glaze with stain for the additive per-centage of 0.5 , 1, 5, 10, 15 wt% In thie colouring of Lime base glaze with the wide ranged melting tem-perature the colour development of cobalt-blue sintered at $1250^{\circ}C$ is better than that of $1150^{\circ}C$ $1350^{\circ}C$ The experimental conditions and data are D-based simulated programming of computer. The result of -based data appeared to be more smoothed fusion-adherence in the Matt glaze range of Lime base glaze, The variation of colouring is not found when additive content of glaze is more than 5 wt% and the stable colour development of stain was shown at the content that RO, $R_2O$ percentage is high (the content that R2O3 per-centage is low)

• Structural Engineering and Mechanics
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• 제82권4호
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• pp.477-490
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• 2022

This article investigates the nonlinear behavior of two-directional functionally graded materials (TDFGM) doubly curved panels with porosities for the first time. An improved and effectual approach is established based on the improved first-order shear deformation shell theory (IFSDST) and von Karman's type nonlinearity. The IFSDST considers the effects of shear deformation without the need for a shear correction factor. The composition of TDFGM constitutes four different materials, and the modified power-law function is employed to vary the material properties continuously in both thickness and longitudinal directions. A nonlinear finite element method in conjunction with Hamilton's principle is used to obtain the governing equations. Then, the direct iterative method is incorporated to accomplish the numerical results using the frequency-amplitude, nonlinear central deflection relations. Finally, the influence of volume fraction grading indices, porosity distributions, porosity volume, curvature ratio, thickness ratio, and aspect ratio provides a thorough insight into the linear and nonlinear responses of the porous curved panels. Meanwhile, this study emphasizes the influence of the volume fraction gradation profiles in conjunction with the various material and geometrical parameters on the linear frequency, nonlinear frequency, and deflection of the TDFGM porous shells. The numerical analysis reveals that the frequencies and nonlinear deformations can be significantly regulated by changing the volume fraction gradation profiles in a specified direction with an appropriate combination of materials. Hence, TDFGM panels can overcome the drawbacks of the functionally graded materials with a gradation of properties in a single direction.