• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2022.04a
• /
• pp.172-173
• /
• 2022

Rough stones of aggregates used as concrete aggregates for 6 regions in Korea were sampled and the reactivity of alkali aggregates was analyzed using chemical analysis method and mortar rod method.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.11a
• /
• pp.255-256
• /
• 2023

The purpose of this study is to confirm the feasibility of exploring the location of reinforcing bars using the resistivity method in concrete structures.

• Korean Journal of Remote Sensing
• /
• v.35 no.6_1
• /
• pp.973-985
• /
• 2019

In this paper, we propose a method to separate the ground and building areas and generate building models automatically through planarity analysis using UAV (Unmanned Aerial Vehicle) based point cloud. In this study, proposed method includes five steps. In the first step, the planes of the point cloud were extracted by analyzing the planarity of the input point cloud. In the second step, the extracted planes were analyzed to find a plane corresponding to the ground surface. Then, the points corresponding to the plane were removed from the point cloud. In the third step, we generate ortho-projected image from the point cloud ground surface removed. In the fourth step, the outline of each object was extracted from the ortho-projected image. Then, the non-building area was removed using the area, area / length ratio. Finally, the building's outer points were constructed using the building's ground height and the building's height. Then, 3D building models were created. In order to verify the proposed method, we used point clouds made using the UAV images. Through experiments, we confirmed that the 3D models of the building were generated automatically.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.25 no.1
• /
• pp.19-30
• /
• 2007

Modeling 3D buildings is an essential process to revive the real world into a computer. There are two ways to create a 3D building model. The first method is to use the building layer of 1:1000 digital maps based on high density point data gained from airborne laser surveying. The second method is to use LiDAR point data with digital images achieved with LiDAR. In this research we tested one sheet area of 1:1000 digital map with both methods to process a 3D building model. We have developed a process, analyzed quantitatively and evaluated the efficiency, accuracy, and reality. The resulted differed depending on the buildings shape. The first method was effective on simple buildings, and the second method was effective on complicated buildings. Also, we evaluated the accuracy of the produced model. Comparing the 3D building based on LiDAR data and digital image with digital maps, the horizontal accuracy was within ${\pm}50cm$. From the above we derived a conclusion that 3D building modeling is more effective when it is based on LiDAR data and digital maps. Using produced 3D building modeling data, we will be utilized as digital contents in various fields like 3D GIS, U-City, telematics, navigation, virtual reality and games etc.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.3
• /
• pp.255-264
• /
• 2007

In the current domestic and overseas standards concerning seismic design, especially on the capacity & demand spectra in the multi-story building, failure is caused more by story drift than by displacement; and the existing capacity spectrum method (CSM) does not make a close estimate of story drift because response is derived using displacement. Therefore, this paper proposes an improved CSM to estimate story drift and its direct effect on the collapse of structures, yet still maintaining the same advantage and convenience of the existing CSM about a most basic model of multi-story building: shear building. To establish its reliability, the proposed method is applied to an example model and results are then compared with those obtained through nonlinear time-history analysis.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.4
• /
• pp.40-48
• /
• 2016

The construction industry has been made diversified on the design process depending on qualitative growth of customers' demands. But this approach has lead to problems such as falling of building values due to lack of awareness of defects caused by long term utilization. So, the relationship on the characteristics of buildings and defects should be clearly analyzed to prevent falling of building values. This study, therefore, proposed a technique to quantify the relationship between building facade elements and defects. The technique was developed by applying pixel concept to the outside of the buildings. It has a feature to determine the clear relationship by presenting quantitative data that have been recognized qualitatively. The proposed technique is referred to "Pixelization Method". It separates building facade into unit compartment and makes database by assigning a code depending on the characteristics. Through the method, this study is expected to create a foundation for the quantitative analysis of relationship between building facade elements and defects as a basis on active responding to the defects.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.1
• /
• pp.74-89
• /
• 2021

For higher-level requirements of urban planning and management and the recent development of "digital earth" and "digital city", it is urgent to establish protocols for the construction of three-dimensional digital city models. However, some problems still exist in the digital technology of the three-dimensional city model, such as insufficient precision of the three-dimensional model, not optimizing the scene and not considering the constraints of building codes. In view of those points, a method to interactively simulate a virtual city scene based on building codes is proposed in this paper. Firstly, some constraint functions are set up to restrict the models to adhere to the building codes, and an improved directional bounding box technique is utilized to solve the problem that geometric objects may intersect in a virtual city scene. The three-dimensional model invocation strategy is designed to convert two-dimensional layouts to a three-dimensional urban scene. A Leap Motion hardware device is used to interactively place the 3D models in a virtual scene. Finally, the design and construction of the three-dimensional scene are completed by using Unity3D. The experiment shows that this method can simulate urban virtual scenes that strictly adhere to building codes in a virtual scene of the city environment, but also provide information and decision-making functions for urban planning and management.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.3
• /
• pp.341-348
• /
• 2020

The ability to extract useful information from an image, such as the human eye, is an interface technology essential for AI computer implementation. The building recognition technology has a lower recognition rate than other image recognition technologies due to the various building shapes, the ambient noise images according to the season, and the distortion by angle and distance. The computer vision based building recognition algorithms presented so far has limitations in discernment and expandability due to manual definition of building characteristics. This paper introduces the deep learning CNN (Convolutional Neural Network) model, and proposes new method to improve the recognition rate even by changes of building images caused by season, illumination, angle and perspective. This paper introduces the partial images that characterize the building, such as windows or wall images, and executes the training with whole building images. Experimental results show that the building recognition rate is improved by about 14% compared to the general CNN model.

• Structural Engineering and Mechanics
• /
• v.64 no.4
• /
• pp.473-485
• /
• 2017

An isolated building, composed of superstructure and isolation system which have very different damping properties, is typically non-classical damping system. This results in inapplicability of traditional response spectrum method for isolated buildings. A multidimensional response spectrum method based on complex mode superposition is herein introduced, which properly takes into account the non-classical damping feature in the structure and a new method is developed to estimate velocity spectra from the commonly used displacement or pseudo-acceleration spectra based on random vibration theory. The error of forced decoupling method, an approximated approach, is discussed in the viewpoint of energy transfer. From the base-isolated benchmark model, as a numerical example, application of the procedure is illustrated companying with comparison study of time-history method, forced decoupling method and the proposed method. The results show that the proposed method is valid, while forced decoupling approach can't reflect the characteristics of isolated buildings and may lead to insecurity of structures.

• Advances in Computational Design
• /
• v.1 no.4
• /
• pp.329-344
• /
• 2016

In this paper, a methodology to simulate the whole-building behaviour of the tall building under fire is developed by the author using a 3-D nonlinear finite element method. The mechanical and thermal material nonlinearities of the structural members, such as the structural steel members, concrete slabs and reinforcing bars were included in the model. In order to closely simulate the real condition under the conventional fire incident, in the simulation, the fire temperature was applied on level 9, 10 and 11. Then, a numerical investigation on the whole-building response of the building in fire was made. The temperature distribution of the floor slabs, steel beams and columns were predicted. In addition, the behaviours of the structural members under fire such as beam force, column force and deflections were also investigated.