• 대한원격탐사학회지
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• 제29권5호
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• pp.499-508
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• 2013

각종 센서 정보에 기반한 3차원 건물 정보 추출 방법은 건물 형태를 보다 상세하게 묘사할 수 있지만 많은 비용 및 복잡한 처리가 요구된다. 단일 고해상도 영상에 기반한 방법은 추출할 수 있는 3차원 건물 정보가 비교적 제한적이지만 낮은 비용과 단순한 처리 과정으로 건물 정보를 추출할 수 있다는 장점을 갖는다. 단일 고해상도 위성영상만을 이용한 건물 정보 추출 방법 중에서도 Volumetric Shadow Analysis(VSA)는 그림자나 건물 밑 바닥이 일부분 가려져도 해당 건물의 높이와 바닥 위치 정보를 추출할 수 있다. 최근에는 반자동 VSA가 제안되었으나 이 방법은 주변 객체 형태와 그림자 영역 추출 정확도, 영상 노이즈 등에 큰 영향을 받는다. 반자동 VSA를 개선하기 위해서 본 논문은 단일 고해상도 전정색 영상과 다중분광 영상을 이용한 3차원 건물 정보 추출 방법을 제안한다. 제안된 방법은 각 밴드 영상에 반자동 VSA를 각각 적용하고 이를 통해서 계산된 파라미터로 비용함수를 구성한다. 비용함수로 계산된 값이 최대인 건물 높이를 실제 건물 높이로 결정한다. 제안된 방법의 성능평가를 위해서 Kompsat-2 영상이 사용되었으며 반자동 VSA와 제안된 방법으로 추출된 건물 정보를 비교 분석하였다. 그 결과는 제안된 방법이 보다 높은 성공률로 비교적 정확한 건물 정보를 추출할 수 있음을 보여준다.

• Architectural research
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• 제2권1호
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• pp.55-60
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• 2000

Recently, there is a great demand for precast reinforced concrete (RC) construction methods on the purpose of simplicity in construction. Nishimatsu Construction Company has developed a construction method with precast reinforced concrete members in medium-rise building. In this construction method, how to joint precast members, especially the anchorage of the main bar of beam, is important problem. In this study, the structural performance of exterior joints with precast members was investigated. The parameters of the test specimens are anchorage type of the main bar of beam (U-shape anchorage or anchorage plate) and the ratio of the column axial force to the column strength. Specimens J-3 and J-4 used U-shape anchorage and the ratio of the column axial force of specimen J-4 was higher. On the other hand, specimens J-5 and J-6 used anchorage plate, and the anchorage lengths are 15d and 18d, respectively. Experimental results are summarized as follows; 1) For the joints with beam flexural failure mode, it was found that the maximum strength of specimen with anchorage plate is equal to or larger than that of specimen with conventional U-shaped anchorage if the anchorage length of more than 15d would be ensured, 2) Each specimen shows stable hysteretic curves and there were no notable effects on the hysteretic characteristics and the maximum strength caused by the anchorage method of beam main bar and the difference of column axial stress level.

• 지질공학
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• 제32권4호
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• pp.449-466
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• 2022

지하공간을 구성하고 있는 지중구조물, 지반, 암반 등 다양한 구성 요소 중에 지질공학적 측면을 포함한 모든 정보에 대한 모델 구축은 현실적으로 어려운 과정이며, 현재 진행형인 분야이다. 본 연구에서는 지질공학적인 정보모델 구축 과정이 비교적 쉬운 상용 소프트웨어를 활용하여 제주도 일부 지역 대상의 3차원 지질정보모델, 동굴형상정보모델, 도로 주변 현황 정보모델까지 한 번에 디지털화하는 과정이 포함되어 있다. 제주도에 존재하는 수많은 자연동굴 중에 도로와 교차하는 위치 중 제주도 한림 재암천굴을 대상으로 CaveBIM 기반의 디지털 트윈 구축에 관한 연구를 수행 중이다. 본 연구에서는 3D 레이저 스캐너를 사용한 동굴 형상 정보모델링, 지질 정보 및 지구물리탐사 자료를 활용한 3D 지질 모델링, 드론을 활용한 재암천굴 상부 도로 주변 현황 정보모델링 등의 개별 데이터 구축과 통합을 통해서 디지털화하는 과정을 포함하고 있다. 본 연구에서는 한림-제주 지역에 대한 전역모델(GSM) 및 재암천굴에 대한 국부모델(LSM)을 구축하였다. 또한 재암천굴에 대한 LSM 구축 시 교차검증을 수행하여 결과를 비교 및 분석하였다.

• Wind and Structures
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• 제22권3호
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• pp.307-328
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• 2016

This paper describes an investigation of the net wind loads on solar panels and wind loads on the underlying roof surface for panels mounted parallel to pitched roofs of domestic buildings. Typical solar panel array configurations were studied in a wind tunnel and the aerodynamic shape factors on the panels were put in a form appropriate for the Australian/New Zealand Wind Actions Standard AS/NZS 1170.2:2011. The results can also be used to obtain more refined design data on individual panels within an array. They also suggest values for the aerodynamic shape factors on the roof surface under the panels, based on a gust wind speed at roof height, of ${\pm}0.5$ for wind blowing parallel to the ridge, and ${\pm}0.6$ for wind blowing perpendicular to the ridge. The net loads on solar arrays in the middle portion of the roof are larger than those on the same portion of the roof without any solar panels, thus resulting in increased loads on the underlying roof structure.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 2001년도 International Conference CALS/EC KOREA
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• pp.615-624
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• 2001

Internet technology opens up another domain for building future CAD/CAM environment. The environment will be global, network-centric, and spatially distributed. In this paper, we present a new approach to network-centric virtual prototyping (NetVP) in a distributed design environment. The presented approach combines the current virtual assembly modeling and analysis technique with distributed computing and communication technology fur supporting virtual prototyping activities over the network. This paper focuses on interoperability, shape representation, and geometric processing for distributed virtual prototyping. STEP standard and CORBA-based interfaces allow the bi-directional communication between the CAD model and virtual prototyping model, which makes it possible to solve the problems of interoperability, heterogeneity of platforms, and data sharing. STEP AP203 and AP214 are utilized as a means of transferring and sharing product models. In addition, Attributed Abstracted B-rep (AAB) is introduced as 3D shape abstraction for transparent and efficient transmission of 3D models and for the maintenance of naming consistency between CAD models and virtual prototyping models over the network.

• 한국산학기술학회논문지
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• 제16권10호
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• pp.6673-6678
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• 2015

최근 빈번히 건설되고 있는 비정형 건축물들은, 개별부재의 수직/수평적 연결방식 에서 벗어나, 외관 및 내부 구성요소들의 단면이 자유롭게 변화되는 곡선의 형태를 띠고 있다. 이러한 구조물의 안정성 평가를 위해서 고전적 방식의 유한요소 해석기법이 적용된 상용프로그램이 사용되고 있으나, 과도한 절점분할 방식 또는 유한요소망(Finite Element Mesh)의 도입으로 인하여 해석시간이 길어지고 사용성 및 해석 정밀도가 낮은 문제점을 안고 있다. 따라서 본 연구에서는, 전술된 문제점을 개선하기 위하여, 임의의 곡률을 가진 단위 부재 및 단위요소에 대한 수학적 해석모형을 활용하여 비정형구조물에 대한 구조안정성 평가를 효과적으로 수행할 수 있는 전후처리 모듈을 개발하였다. 본 연구에서 개발된 전후처리 모듈은 곡선형 부재의 곡률을 NURBS 제어점을 이용하여 제어할 수 있도록 개발되었으며, 그로 인해 상용프로그램보다 빠른 형상 모델링이 가능하였다. 또한, 자유로운 형상에 대한 시각적 확인이 가능하여 비정형 건축물의 형상과 거동양상의 현실적인 묘사가 가능하였다.

• 한국BIM학회 논문집
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• 제11권4호
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• pp.20-30
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• 2021

In the era of the 4th industrial revolution, smart construction is actively researched, in the domestic construction field, and one of the key elements in this field is Building Information Modeling(BIM). In Korea, smart construction is being implemented through BIM-based digitization and intelligence. The geotechnical engineering field should also prepare for the introduction of BIM. In this study, the concept and application status of GeoBIM were identified, and the direction of future research was presented. This study is a part of the study "Establishment of GeoBIM-based Digital Twin Maintenance System" in the current "Technology Development for Establishment of Jeju Ground Collapse Response System for Safe Road Operation". The subject and scope of the study is continuous excavation at caves located under roads in Jeju Island, and initial research is being conducted on Jaeamcheon-gul and Jeonggusu-gul. This study aims to build a digital twin through individual data construction and integration processes such as cave shape modeling using laser scanners, 3D stratum modeling using borehole information and geophysical exploration data, and modeling of surrounding conditions using drones.

• 한국의상디자인학회지
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• 제15권2호
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• pp.77-89
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• 2013

This study investigated the formation of silhouette and hemline shape of knit flare skirts according to the properties of knit material through virtual clothing with a 3D virtual clothing system called i-Designer of Technoa, thus building a database of the property data of knit material to reduce the number of sample making steps repeated and implemented several times in the process of clothes making. The results would help to estimate a silhouette in advance, offer assistance to the development of original knit wear, and explore ways to provide basic data for the development of the knit industry of the nation. The investigator made 12 kinds of experimental clothes to the angles(width of skirt: $90^{\circ}$ and $180^{\circ}$), gauge(7G, 12G, and 15G), and grain directions(wale and bias direction) of experimental clothes for virtual clothing. The dynamic characteristics of knit skirt samples according to each gauge were measured with the KES-FB system. Draper shapes were analyzed with the sectional shape data of hemline based on i-Designer. As for the measurements of the sectional shape of hemline and the formation of silhouette, the number of nodes, the average height of node mountains and valleys, and the hemline width right and left and before and after increased at the angle of $180^{\circ}$ than $90^{\circ}$. As gauges multiplied, the number of nodes, and silhouette angle dropping. When considering grain directions, the number of nodes and silhouette index increased in the wale direction at the angle of $90^{\circ}$ with the number of nodes and silhouette angle increasing in the wale direction at the angle of $180^{\circ}$.

• Structural Engineering and Mechanics
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• 제20권3호
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• pp.313-334
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• 2005

The paper presents a new approach for the analysis of slope stability that is based on the numerical solution of a differential equation, which describes the thrust force distribution within the potential sliding mass. It is based on the evaluation of the thrust force value at the endpoint of the slip line. A coupled approximation of the slip and thrust lines is applied. The model is based on subdivision of the sliding mass into slices that are normal to the slip line and the equilibrium differential equation is obtained as the slice width approaches zero. Opposed to common iterative limit equilibrium procedures the present method is straightforward and gives an estimate of slope stability at the value of the safety factor prescribed in advance by standard requirements. Considering the location of the thrust line within the soil mass above the trial slip line eliminates the possible development of a tensile thrust force in the stable and critical states of the slope. The location of the upper boundary point of the thrust line is determined by the equilibrium of the upper triangular slice. The method can be applied to any smooth shape of a slip line, i.e., to a slip line without break points. An approximation of the slip and thrust lines by quadratic parabolas is used in the numerical examples for a series of slopes.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1237-1242
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• 2007

For the various RP processes and machines, quantitative comparisons were carried out, which include the variations of roughness according to inclined angle of surface, tensile strength and heat-resistance, shape accuracy affected by curl distortion, manufacturability of submilli-scale structure, and manufacturing speed. It was observed that steeper surface results in smoother roughness except Eden500V of Objet. Specimen made by LOM process showed the best heat-resistance, but that of SL process had heat-resistance only up to $60^{\circ}C$. Generally, tensile strength in the building direction was shown to be smaller than in the scanning direction, but SL process showed the opposite results. RM6000II of CMET was superior in the manufacturing small-scale structure below 0.2mm, and Z510 of Zcorp. and ViperPRO of 3D systems were great in manufacturing speed.