• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.5
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• pp.343-349
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• 2021

In The process from design to construction in the existing construction work was less efficient due to the contradictory approach of identifying the 3D state in the plan view and the repeated generation of surveys, floor plans, drawings. Accurate 3D design data is essential for smart construction. However, most of the existing related studies have focused on explaining the development method and main functions of equipment or improving the productivity of smart construction. Therefore, in this study, the utility of 3D design model generation for smart construction and construction survey using 3D laser scanner was evaluated. Plane and vertical road alignment were created using the specifications of the road. The generated road alignment was created as a three-dimensional corridor design using cross-sections at intervals of 20m. In addition, it was possible to create a DTM (Digital Terrain Model) using a digital map and effectively create a 3D design model for the study area through overlapping. Construction survey using a 3D laser scanner showed accuracy within 10cm as a result of the accuracy evaluation. These results proved that construction surveying using a 3D laser scanner is possible because it satisfies the acceptable accuracy of the relevant regulations modeling of target areas using 3D design and construction survey using 3D laser scanner can be a way to address shortcomings of existing GNSS (Global Navigation Satellite System) methods. And accurate 3D data will be used as essential data as basic data for smart construction.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1067-1074
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• 2022

An architect creates his/her design to meet owner's requirements. Floor plans, perspective drawings, and scale models are used in order for the owner to choose the design. The tools are a little helpful for communication between the architect and the owner in case the owner does not know architecture. The scale models are good, but it is hard to make scale models while design is in progress. 3D CAD is a good tool for communication, but it is time-consuming and requires high-performance computer hardware. Augmented reality is able to show 3D virtual models that are updated by the architect with smart devices such as a smart phone and a tablet PC. The owner frequently reviews the updated design anytime anywhere. This study proposes a method to use augmented reality for architectural design and construction management. The method supports the communication between the owner, the architect and the contractor to review updated designs, and to complete the building project. 3D models expressed in augmented reality are created using SketchUp with 2D drawings for building construction. An Android application implementing augmented reality is developed by Qualcomm Vuforia and Unity on smart devices. Drawings as markers and 3D models are connected in Unity. And functions that temporarily hide unnecessary parts can be implemented in C# programming language. If an owner, an architect, or a contractor looks at a smart phone on a 2D drawing, he/she can identify building elements such as 3D buildings or columns on a screen. This can help communication between them.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.65-70
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• 2010

This paper presents experimental performance evaluation of a magnetorheological (MR) damper for integrated isolation mount for ultra-precision manufacturing system. The vibration sources of the ultra-precision manufacturing system can be classified as follows: the one is the environmental vibration from the floor and the other is the transient vibration occurred from stage moving. The transient vibration occurred from the stage moving has serious adverse effect to the process because the vibration scale is quite larger than other vibrations. Therefore in this research, a semi-active MR damper, which can control the transient vibration, is adopted. Also the stage needs to be isolated from tiny vibrations from the floor. For this purpose, a dry-frictionless MR damper is required. In order to achieve this goal, a novel type of MR damper is originally designed and manufactured in this work. Subsequently, the damping force characteristics of MR damper are evaluated by simulation and experiment. In addition, the vibration control performance of the MR damper associated with the stage mass is evaluated.

• Smart Structures and Systems
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• v.20 no.1
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• pp.23-33
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• 2017

Variable Curvature Friction Pendulum (VCFP) bearing is one of the alternatives to control excessive induced responses of isolated structures subjected to near-fault ground motions. The curvature of sliding surface in this isolator is varying with displacement and its function is non-spherical. Selecting the most appropriate function for the sliding surface depends on the design objectives and ground motion characteristics. To date, few polynomial functions have been experimentally tested for VCFP however it needs comprehensive parametric study to find out which one provides the most effective behavior. Herein, seismic performance of the isolated structure mounted on VCFP is investigated with two different polynomial functions of the sliding surface (Order 4 and 6). By variation of the constants in these functions through changing design parameters, 120 cases of isolators are evaluated and the most proper function is explored to minimize floor acceleration and/or isolator displacement under different hazard levels. Beside representing the desire sliding surface with adaptive behavior, it was shown that the polynomial function with order 6 has least possible floor acceleration under seven near-field ground motions in different levels.

• Smart Structures and Systems
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• v.4 no.1
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• pp.85-98
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• 2008

In this paper, excitation systems using a linear mass shaker (LMS) and an active tuned mass damper (ATMD) are presented to simulate the wind induced responses of a building structure. The actuator force for the excitation systems is calculated by using the inverse transfer function of a target structural response to the actuator. Filter and envelop functions are used to prevent the actuator from exciting unexpected modal responses and an initial transient response and thus, to minimize the error between the wind and actuator induced responses. The analyses results from a 76-story benchmark building problem for which the wind load obtained by a wind tunnel test is given, indicate that the excitation system installed at a specific floor can approximately reproduce the structural responses induced by the wind load applied to each floor of the structure. The excitation system designed by the proposed method can be effectively used for evaluating the wind response characteristics of a practical building structure and for obtaining an accurate analytical model of the building under wind load.

• Smart Structures and Systems
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• v.25 no.5
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• pp.531-541
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• 2020

This paper demonstrates the possibility of evaluating the safety of a building right after an earthquake using consumer-grade surveillance cameras installed in the building. Two cameras are used in each story to extract the time history of interstory drift during the earthquake based on camera calibration, stereo triangulation, and image template matching techniques. The interstory drift of several markers on the rigid floor are used to estimate the motion of the geometric center using the least square approach, then the horizontal interstory drift of any location on the floor can be estimated. A shaking table collapse test of a steel building was conducted to verify the proposed approach. The results indicate that the accuracy of the interstory drift measured by the cameras is high enough to estimate the damage state of the building based on the fragility curve of the interstory drift ratio. On the other hand, the interstory drift measured by an accelerometer tends to underestimate the damage state when residual interstory drift occurs because the low frequency content of the displacement signal is eliminated when high-pass filtering is employed for baseline correction.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.451-458
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• 2006

The goal of many researchers in the field of structural engineering is to reduce both damage to building structures and discomfort of their inhabitants during strong motion seismic events. The present paper reports on analytical work conducted with this aim in mind as a prior research of experimental study. A four-story, 6.4 m tall, laboratory model of a building is employed as a example structure. The laboratory structure has graphite epoxy columns and each floor is equipped with a chevron brace that serves to resist inter-story drift with the installation of a magnetorheological (MR) damper. An artificial excitation has been generated with a robust range of seismic characteristics. A series of numerical simulations demonstrates that an optimized fuzzy controller is capable of robust performance for a variety of seismic base motions. Optimization of the fuzzy controller is achieved using multi-objective genetic algorithm(MOGA), i.e. NSGA-II. Multiple objective functions are used in order to reduce both peak and root-means-squared displacement and accelerations at the floor levels of the building.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.12
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• pp.1161-1167
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• 2010

This paper presents experimental performance evaluation of a magnetorheological(MR) damper for integrated isolation mount for ultra-precision manufacturing system. The vibration sources of the ultra-precision manufacturing system can be classified as follows: the one is the environmental vibration from the floor and the other is the transient vibration occurred from stage moving. The transient vibration occurred from the stage moving has serious adverse effect to the process because the vibration scale is quite larger than other vibrations. Therefore in this research, a semi-active MR damper, which can control the transient vibration, is adopted. Also the stage needs to be isolated from tiny vibrations from the floor. For this purpose, a dry-frictionless MR damper is required. In order to achieve this goal, a novel type of MR damper is originally designed and manufactured in this work. Subsequently, the damping force characteristics of MR damper are evaluated by simulation and experiment. In addition, the vibration control performance of the MR damper associated with the stage mass is evaluated.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.815-817
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• 2022

This paper is about the development of an automatic stair climbing trolley for carrying loads without manpower. The design of tri-wheeled structure and center of mass enable the trolley to move on flat ground and also to ascend stairs by self-balancing. The overall design enables the trolley to avoid collision to walls when the trolley rotates on domestic landings. When the camera recognizes the stair, the sensor measures distance from the trolley to the stair. Then the trolley can move to align itself in the middle of the stair and it starts climbing. It can ascend to a specific floor based on the floor number entered by the user. As a result, the automatic stair climbing trolley is expected to help humans by protecting from accidents of dropping loads and saving their power. It is also expected to use for various purposes such as delivering packages, moving and carrying heavy loads in buildings without elevator.

• Smart Structures and Systems
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• v.14 no.4
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• pp.595-615
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• 2014

This study aims to investigate the relationship between structural damage and sensitivity indices using the Hilbert-Huang transform (HHT) method. Two damage detection indices are proposed: the ratio of bandwidth (RB), and the ratio of effective stiffness (RES). The nonlinear four bays multiple degree of freedom models with various predominant frequencies are constructed using the SAP2000 program. Adjusted PGA earthquake data (Japan 311, Chi-Chi 921) are used as the excitations. Next the damage detection indices obtained using the HHT and the fast Fourier transform (FFT) methods are evaluated based on the acceleration responses of the structures to earthquakes. Simulation results indicate that, the column of the 1 st floor is the first yielding position and the RB value is changed when the RES<90% in all cases. Moreover, the RB value of the 1 st floor changes more sensitive than those from the top floor. In addition, when the structural response is nonlinear (i.e., RES<100%), the RB and the RES curves indicate the incremental change in the HHT spectra. However, the same phenomenon can be found from FFT spectra only when the stiffness reduction is large enough. Therefore, the RB estimated from the smoothed HHT spectra is an effective and sensitive index for detecting structural damage.