• 환경생물
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• 제38권3호
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• pp.476-480
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• 2020

A marine red algal species was collected from Uljin, located on the eastern coast of Korea, during a survey of marine algal flora. This alga shares the generic features of Plocamium, and is characterized by linear, flat and thin thalli with narrow axes, branches developing in alternating pairs from margins of the axes, two to four times alternately pinnately branching, linear or occasionally adaxially curved lowermost branchlets and distinctly and compactly clustered stichidia. In a phylogenetic tree based on rbcL sequences, the Korean alga nests in the same clade as P. serrulatum. The genetic distance between both sequences within the clade was calculated as 0.0-0.2%. Based on the morphological and molecular data, this Korean species is identified as P. serrulatum described originally from Taiwan. This is the first record of P. serrulatum in Korean marine algal flora.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.679-685
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• 2003

Rotem has been using VAMPIRE for simulation and verification of the railway vehicle design. To improve the capability and accuracy of the analysis ability, ADAMS/Rail has been chosen as the next generation analysis tool. The dynamic performance of the railway vehicle, which is designed and manufactured by Rotem, is analyzed and simulated using ADAMS/Rail. The critical speed for linear and non-linear stability on tangent track, curving performance on various curved tractk, ride quality, derailment coefficient and the eigen values are calculated. In this paper, the results from ABAMS/Rail are compared with VAMPIRE's results.

• 한국실내디자인학회논문집
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• 제24권2호
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• pp.78-87
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• 2015

This study aims to grasp the vital rhythm of the Chapel at Ronchamp by analyzing its rhythm through Henri Lefebvre's 'rhythmanalysis' in an effort to show the possibility of approaching the presence of this chapel. For the purpose of this study, Lefebvre's thought of rhythmanalysis was first contemplated, and a case study analysis was conducted on the concept and presence of the chapel in the design process. On this basis, examples of the chapel's rhythms were analyzed through Lefebvre's dialectical analysis of the triad of time(melody), space(harmony) and energy(rhythm). The results of analysis are as follows: First, the concept intended by Le Corbusier in the process of designing the Chapel at Ronchamp is expressed as the acoustic form, the modulor corresponding to the scale of the music, the light and shadow of counterpoint, and the opposite composition of musical changes. Consequently, the concept-mediated presence of this chapel is the presence of music. Second, at the Chapel at Ronchamp, a Lefebvre's rhythmanalyst experiences, or rather senses, two vital rhythms of an antithetical unity (i.e., acoustic curved rhythm and modulor-generated linear rhythm), with reference to his/her own rhythms. These rhythms are a dialectical union of spatiality of melodies temporalized through continuity, (i.e., acoustic curved form and modulor-generated linear form), and temporality of harmonies spatialized through simultaneity (i.e., light and shadow, materials and color, form of interpenetration, and stairs or windows/doors). These rhythms carry the measures generated by music-specific repetitions and differences in movements(energy). Consequently, the rhythm-mediated presence of this chapel is also the presence of music. In conclusion, the Chapel of Ronchamp indicates that an approach toward its presence can be realized through vital rhythms derived from Lefebvre's 'rhythmanalysis'. This study holds significance as an analysis of spatial rhythm and presence, employing a philosophical thought.

• Steel and Composite Structures
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• 제37권2호
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• pp.117-136
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• 2020

Curved steel-concrete composite box girder has been widely adopted in urban overpasses and ramp bridges. In order to investigate its mechanical behavior under complicated and combined bending, shear and torsion load, two large-curvature composite box girders with interior angles of 25° and 45° were tested under static hogging moment. Based on the strain and deflection measurement on critical cross-sections during the static loading test, the failure mode, cracking behavior, load-displacement relationship, and strain distribution in the steel plate and rebar were investigated in detail. The test result showed the large-curvature composite box girders exhibited notable shear lag in the concrete slab and steel girder. Also, the constraint torsion and distortion effect caused the stress measured at the inner side of the composite beam to be notably higher than that of the outer side. The strain distribution in the steel web was approximately linear; therefore, the assumption that the plane section remains plane was approximately validated based on strain measurement at steel web. Furthermore, the full-process non-linear elaborate finite element (FE) models of the two specimens were developed based on commercial FE software MSC.MARC. The modeling scheme and constitutive model were illustrated in detail. Based on the comparison between the FE model and test results, the FE model effectively simulated the failure mode, the load-displacement curve, and the strain development of longitudinal rebar and steel girder with sufficient accuracy. The comparison between the FE model and the test result validated the accuracy of the developed FE model.

• 정보과학회 논문지
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• 제44권4호
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• pp.392-398
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• 2017

포인트 클라우드를 이용한 물체의 표현은 레이저 스캐너를 통해 공간을 스캔하여 점의 집합을 추출하고, 정합(Registration)을 통해 하나의 좌표계로 통합하는 과정을 거쳐 이루어진다. 정합이 완료된 포인트 클라우드 집합은 수학적 해석을 통해 의미 있는 영역, 형태, 잡음 등으로 분류되어 쓰이게 된다. 본 논문은 3차원 포인트 클라우드 데이터에서 실린더 형태의 굽은 영역 매칭을 목표로 한다. 매칭 절차는 포인트 클라우드에서 RANdom SAmple Consensus(RANSAC)을 통한 구(sphere) 적합(fitting)으로 실린더 형태의 점 후보군을 추출하여 중심과 반지름 데이터를 얻고, 추출된 중심점 데이터에서 주성분 분석(Principal Component Analysis)을 통해 굽은 영역인지 판별한 후 캣멀롬 스플라인(Catmull-Rom spline)으로 굽은 영역 매칭을 완료한다. 제안된 방법은 제약조건 및 분할 없이 중심축 추정에 이은 직선 및 굽은 형태의 실린더 추정으로 비교적 빠른 추정결과를 도출하고, 역설계의 작업효율을 높일 수 있을 것으로 기대된다.

• 한국측량학회지
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• 제34권3호
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• pp.243-251
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• 2016

일반적으로 라이다 데이터 처리 과정은 노이즈 제거, 지표면/비지표면 분리를 위한 필터링, 데이터 분류, 객체분할, 형태인식, 객체 모델링, 성과물에 대한 정확도 검증 등이다. 본 논문은 점군집 라이다 데이터를 이용한 3차원 곡면객체의 모델링과 정확도 검증에 중점을 두고 있다. 기존의 구형 및 원통형 객체 모델링 방법은 함수의 선형화, 미지계수의 초기 근사값 및 반복 계산이 요구되지만, 제안한 방법은 모델링 함수의 미지계수를 직접 결정하는 방법이다. 이를 위하여 객체를 형성하는 단위 객체면 형태를 분석하여 적합한 함수를 결정하고, 함수를 구성하는 미지변수를 추정한 후 정확도를 분석하여 타당성을 검증하였다. 제안한 방법을 반구형 및 반원통의 시뮬레이션 및 실제 건물 데이터에 적용하여 모델링 함수의 계수와 정확도를 산정하였으며, 다양한 형태의 객체 모델링의 자동화에 기여할 것으로 판단된다.

• 대한건축학회논문집:계획계
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• 제35권9호
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• pp.89-99
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• 2019

In the representation of buildings with continuous changes in the curved shape of the surface, countless plans or sections are required, or none of the traditional drawings can explain the geometry of it. In other words, in no case can an ordinary drawing achieve the efficient and clear communication capability which is inherent function of the drawings. As a result, the current architects are introducing their own way of drawing technique which is developed in accordance with a specific curved shape, construction method or company resources, but this is not what can be applied to other cases because it has not been ever shared or agreed in the industry. In this process, the drawing or construction of curved building has been recognized as the exclusive property of a specific expert, or the design and construction without the in-depth understanding of the technology have resulted in the appearance of poor buildings. Therefore, this study aims to present an elements and method that can convey shape information more effectively and clearly in the drawing representation of non-linear buildings and, thus, contributes to lowering the barriers to entry into the field by providing the information to be easily applied to related projects. In order to attain this goal, the drawings of recently completed projects of free form building are analyzed to reveal the method used to effectively express the shape information of the building and to derive new drawing elements that have not been applied to the existing drawings.

• 대한기계학회논문집B
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• 제23권8호
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• pp.1063-1071
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• 1999

Fine grid calculations are reported for the developing turbulent flow in a curved duct of square cross-section with a radius of curvature to hydraulic diameter ratio ${\delta}=Rc/D_H=3.357 $ and a bend angle of 720 deg. A sequence of modeling refinements is introduced; the replacement of wall function by a fine mesh across the sublayer and a low Reynolds number algebraic second moment closure up to the near wall sublayer in which the non-linear return to isotropy model and the cubic-quasi-isotropy model for the pressure strain are adopted; and the introduction of a multiple source model for the exact dissipation rate equation. Each refinement is shown to lead to an appreciable improvement in the agreement between measurement and computation.

• 대한조선학회논문집
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• 제45권3호
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• pp.303-308
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• 2008

The induction heating is more efficient for a plate bending because of its easy operation and control of working parameters, compared with the heating by a gas torch. The existing axis symmetric analysis method could neither handle initial curved plates nor be used in the optimization of coil shapes because of its limit of an axis symmetric coil shape. But the proposed method using some discrete part models and analysis processes could overcome these difficulties and show more accurate results in temperatures and deflections of flat or curved plates with initial curvature than those in the existing axis symmetric analysis method. This method is composed of the multi-disciplinary analyses such as an electro magnetic analysis, a heat transfer analysis and a deformation analysis based on inherent strain approach per each step. Traditionally, the coil shape in the induction heating is circular shape and it needs the moving process along heating lines. To overcome this, the 'Long Type Coil' with some linear parallel coils was proposed. It did not need the moving process along heating lines and reduced the heating process time. The results of experiments were compared with those of the simulation.

• Structural Engineering and Mechanics
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• 제77권1호
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• pp.57-74
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• 2021

The thermal eigenvalue responses of the graded sandwich shell structure are evaluated numerically under the variable thermal loadings considering the temperature-dependent properties. The polynomial type rule-based sandwich panel model is derived using higher-order type kinematics considering the shear deformation in the framework of the equivalent single-layer theory. The frequency values are computed through an own home-made computer code (MATLAB environment) prepared using the finite element type higher-order formulation. The sandwich face-sheets and the metal core are discretized via isoparametric quadrilateral Lagrangian element. The model convergence is checked by solving the similar type published numerical examples in the open domain and extended for the comparison of natural frequencies to have the final confirmation of the model accuracy. Also, the influence of each variable structural parameter, i.e. the curvature ratios, core-face thickness ratios, end-support conditions, the power-law indices and sandwich types (symmetrical and unsymmetrical) on the thermal frequencies of FG sandwich curved shell panel model. The solutions are helping to bring out the necessary influence of one or more parameters on the frequencies. The effects of individual and the combined parameters as well as the temperature profiles (uniform, linear and nonlinear) are examined through several numerical examples, which affect the structural strength/stiffness values. The present study may help in designing the future graded structures which are under the influence of the variable temperature loading.