• Wind and Structures
• /
• v.30 no.1
• /
• pp.99-117
• /
• 2020

This paper focuses on the processes of wind flow in atmospheric boundary layer, to produce realistic full scale pressures for design of low-rise buildings. CFD with LES turbulence closure is implemented on a scale 1:1 prototype building. A proximity study was executed computationally in CFD with LES that suggests new recommendations on the computational domain size, in front of a building model, apart from common RANS-based guidelines (e.g., COST and AIJ). Our findings suggest a location of the test building, different from existing guidelines, and the inflow boundary proximity influences pressure correlation and reproduction of peak loads. The CFD LES results are compared to corresponding pressures from open jet, full scale, wind tunnel, and the ASCE 7-10 standard for roof Component & Cladding design. The CFD LES shows its adequacy to produce peak pressures/loads on buildings, in agreement with field pressures, due to its capabilities of reproducing the spectral contents of the inflow at 1:1 scale.

• Spatial Information Research
• /
• v.15 no.2
• /
• pp.123-134
• /
• 2007

The building boundary should be registered in the cadastral map for the protection of property using the expansion of the registration items in the cadastral record and the construction of 3D-cadastral information system. In this study, the efficiency of registering the building boundary was suggested by non-target TS survey through the comparison between target TS and non-target TS survey about an accuracy and efficiency. At the result of this research, the RMSE of target TS and non-target TS survey is the X; ${\pm}0.056m$ and Y; ${\pm}0.043m$. Therefore, non-target TS survey shows the high accuracy. Also, the non-target TS survey is more efficient cost on time and personnel than target TS.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.30 no.1
• /
• pp.49-58
• /
• 2012

Buildings become complex and diverse with time. It is difficult to extract individual buildings using only an optical image, because they have similar spectral characteristics to objects such as vegetation and roads. In this study, we propose a method to extract building area and boundary through integrating airborne Light Detection and Ranging(LiDAR) data and aerial images. Firstly, a binary edge map was generated using Edison edge detector after applying Adaptive dynamic range linear stretching radiometric enhancement algorithm to the aerial image. Secondly, building objects on airborne LiDAR data were extracted from normalized Digital Surface Model and aerial image. Then, a temporary building areas were extracted by overlaying the binary edge map and building objects extracted from LiDAR data. Finally, some building boundaries were additionally refined considering positional accuracy between LiDAR data and aerial image. The proposed method was applied to two experimental sites for validation. Through error matrix, F-measure, Jaccard coefficient, Yule coefficient, and Overall accuracy were calculated, and the values had a higher accuracy than 0.85.

• Journal of Korean Society for Geospatial Information Science
• /
• v.20 no.4
• /
• pp.117-125
• /
• 2012

Although many studies have been conducted to extract buildings from airborne lidar data, most of them assume that all the boundaries of a building are straight line segments. This makes it difficult to model building boundaries containing curved segments correctly. This paper aims to model buildings containing curved segments as combination of straight lines and arcs. First, two sets of boundary points are extracted by adaptive convex hull algorithm and local convex hull algorithm with a larger radius. Then, arc segments are determined by average spacing of boundary points and intersection ratio of perpendicular lines. Finally, building boundary is modeled through regularization of least squares line or circle fitting. The experimental results showed that the proposed method can model the curved building boundaries as arc segments correctly by completeness of 69% and correctness of 100%. The approach will be utilized effectively to create automatically digital map that meets the conditions of the Korean digital mapping.

• Earthquakes and Structures
• /
• v.3 no.2
• /
• pp.97-115
• /
• 2012

The energy-transmitting boundary, which is used in the well-known finite element method (FEM) program FLUSH, is quite efficient for the earthquake response analysis of buildings considering soil-structure interaction. However, it is applicable only in the frequency domain. The author proposed methods for transforming frequency dependent impedance into the time domain, and studied the time domain transform of the boundary. In this paper, first, the estimation methods for both the halfspace condition under the bottom of the soil model and the pseudo three-dimensional effect were studied with the time domain transmitting boundary. Next, response behavior when using the boundary was studied in detail using a practical soil and building model. The response accuracy was compared with those using viscous boundary, and the boundary that considers the excavation force. Through these studies, the accuracy and efficiency of the proposed time domain transmitting boundary were confirmed.

• Journal of Korean Society of Rural Planning
• /
• v.21 no.1
• /
• pp.89-102
• /
• 2015

With the basic research logic stating that the systematic improvement of rural housing plot's boundary barriers should call for the integrated consideration of their on-and-around installing settings, this study tries to analyse characteristics of installing environment of boundary barriers for improvement works of them. Through literature review and then screening process, 3 influencing and appraisal factors were determined: main house-boundary barrier shortest distance as on-site factor, building coverage as inside one, and attached road width as outside one. 21 study villages were subgrouped into structurally improved(9) and not(12). Site investigation and analysis results showed that the relationship between factors has varied very much, i.e. in some cases it is positive or complementary, but in other cases, negative or crossed. Therefore this study would propose that differentiated and flexible strategies with integrated consideration of on-and-around site installing settings be applied in their improvement projects rather than village-wide unified or straight forwarded ones.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2007.04a
• /
• pp.153-156
• /
• 2007

There have been many studies on extracting building boundaries from LiDAR(Light Detection And Ranging) data. In such studies, points are first segmented, then are further processed to get straight boundary lines that better approximate the real boundaries. In most research in this area, processes like generalization or regularization assume that buildings have only right angles, i.e. all the line segments of the building boundaries are either parallel or perpendicular. However, this assumption is not valid for many buildings. We present a new approach consisting of three steps that is applicable to more complex building boundaries. The three steps consist of boundary tracing, generalization, and regularization. Each step contains algorithms that range from slight modifications of conventional algorithms to entirely new concepts. Four typical building shapes were selected to test the performance of out new approach and the results were compared with digital maps. The results show that the proposed approach has good potential for extracting building boundaries of various shapes.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.25 no.3
• /
• pp.103-110
• /
• 2021

A shake table test is conducted for the three-story reinforced concrete building structure using 0.28 g, 0.5 g, 0.75 g, and 1.0 g of seismic input motions based on the Gyeongju earthquake. Computational efforts are made in parallel to explore the mechanical details in the structure. For engineering practice, the elastic modulus of concrete and rebar in the dynamic analysis is reduced to 38% and 50%, respectively, to calibrate the structure's natural frequencies. The engineering approach to the reduced modulus of elasticity is believed to be due to the inability to specify the flexibility of the actual boundary conditions. This aspect may lead to disadvantages of nonlinear dynamic analysis that can distort local stress and strain relationships. The initial elastic modulus can be applied directly without the so-called engineering adjustment with infinite element models with spring and spring-dashpot boundary conditions. This has the advantage of imposing the system flexibility of the structure on the sub-boundary conditions of springs and damping devices to control its sensitivity in a serial arrangement. This can reflect the flexibility of realistic boundary conditions and the effects of system damping (such as the gap between a concrete footing and shake table, loosening of steel anchors, etc.) in scalar quantities. However, these spring and dashpot coefficients can only be coordinated based on experimental results, making it challenging to select the coefficients in-prior to perform an experimental test.

• Korean Journal of Computational Design and Engineering
• /
• v.19 no.2
• /
• pp.129-137
• /
• 2014

Due to the increase of carbon dioxide and building regulations, BIM is considered a way of low-carbon and eco-friendly building development for its many advantages. The advantages can be maximized with Open BIM since it can produce optimal results for various purposes of energy performance assessment. However there are some problems in data interoperability in the process of Open-BIM based energy performance assessment. To solve such problems, this study focuses on space boundary information interoperability between IFC of Open BIM and IDF format of Energy Plus known as the most accurate and diverse energy performance assessment. The study analyzes the analogous study then figures out the problems of IFC based energy performance analysis, and suggests the way of interoperability. Finally, the development of automation program makes this way much more effective. The study of IFC data interoperability is useful for improving the reliability of Open-BIM based energy assessment.

• Steel and Composite Structures
• /
• v.35 no.2
• /
• pp.249-260
• /
• 2020

The main purpose of this research work is to investigate the free vibration of conical shell structures reinforced by graphene platelets (GPLs) and the elastic properties of the nanocomposite are obtained by employing Halpin-Tsai micromechanics model. To this end, a shell model is developed based on Donnell's theory. To solve the problem, the analytical Galerkin method is employed together with beam mode shapes as weighting functions. Due to importance of boundary conditions upon mechanical behavior of nanostructures, the analysis is carried out for different boundary conditions. The effects of boundary conditions, semi vertex angle, porosity distribution and graphene platelets on the response of conical shell structures are explored. The correctness of the obtained results is checked via comparing with existing data in the literature and good agreement is eventuated. The effectiveness and the accuracy of the present approach have been demonstrated and it is shown that the Donnell's shell theory is efficient, robust and accurate in terms of nanocomposite problems.