• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3D
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• pp.259-267
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• 2012

The development of construction automation systems is proposed as a potent solution to the difficulties encountered by the construction industry and the preparation for the rapidly changing construction environment. A research concerning an intelligent excavation system has taken place since 2006. The intelligent excavation system has several functions for environment sensing, 3D site modeling, work planning, work path generation, unmaned control, and information management. This paper presents a space information model and a work path simulator for work planning and work path generation which is one of key technologies required to apply the earthwork system to the real world. A data structure for an earthwork site is suggested. It overcomes the limitations of previous data structures such as Quadtree and Octree. The work path simulator can generate an effective work path with considering information on work environment, equipment and operator's heuristic. The work path generated by the simulator is compared with that suggested by human operators.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.147-161
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• 2021

Through photogrammetry techniques, what current researches can achieve at present is rough 3D mesh and color map of objects, rather than usable photo-realistic 3D assets. This research aims to propose a new method to create photo-realistic 3D assets that can be used in the field of visualization applications. The new method combines photogrammetry with computer graphics modeling. Through the description of the production process of three objects in the real world - "Bullet Box", "Gun" and "Metal Beverage Bottle," it introduces in details the concept, functions, operating skills and software packages used in the steps including the photograph object, white balance, reconstruction, cleanup reconstruction, retopology, UV unwrapping, projection, texture baking, De-Lighting and Create Material Maps. In order to increase the flexibility of the method, alternatives to the software packages are also recommended for each step. In this research, 3D assets are produced that are accurate in shape, correct in color, easy to render and can be physically interacted with dynamic lighting in texture. The new method can obtain more realistic visual effects at a faster speed. It does not require large-scale teams, expensive equipment and software packages, therefore it is suitable for small studios and independent artists and educational institutions.

• Journal of Sensor Science and Technology
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• v.7 no.6
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• pp.418-425
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• 1998

Stereo cameras are the most widely used sensing systems for automated machines including robots to interact with their three-dimensional(3D) working environments. The position of a target point in the 3D world coordinates can be measured by the use of stereo cameras and the camera calibration is an important preliminary step for the task. Existing camera calibration techniques can be classified into two large categories - linear and nonlinear techniques. While linear techniques are simple but somewhat inaccurate, the nonlinear ones require a modeling process to compensate for the lens distortion and a rather complicated procedure to solve the nonlinear equations. In this paper, a method employing a neural network for the calibration problem is described for tackling the problems arisen when existing techniques are applied and the results are reported. Particularly, it is shown experimentally that by utilizing the function approximation capability of multi-layer neural networks trained by the back-propagation(BP) algorithm to learn the error pattern of a linear technique, the measurement accuracy can be simply and efficiently increased.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.611-622
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• 2020

As the advancement of technologies on indoor positioning systems and measuring devices such as LiDAR (Light Detection And Ranging) and cameras, the demands on analyzing and searching indoor spaces and visualization services via virtual and augmented reality have rapidly increasing. To this end, it is necessary to model 3D objects from measured data from real-world structures. In addition, it is important to store these structured data in standardized formats to improve the applicability and interoperability. In this paper, we propose a method to construct IndoorGML data, which is an international standard for indoor modeling, from point cloud data acquired from LiDAR sensors. After examining considerations that should be addressed in IndoorGML data, we present a construction method, which consists of free space extraction and connectivity detection processes. With experimental results, we demonstrate that the proposed method can effectively reconstruct the 3D model from point cloud.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.171-176
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• 2021

Die-to-wafer (D2W) hybrid bonding in the multilayer semiconductor manufacturing process is one of wafer direct bonding, and various studies are being conducted around the world. A noteworthy point in the current die-to-wafer process is that a lot of voids occur on the bonding surface of the die during bonding. In this study, as a suggested method for removing voids generated during the D2W hybrid bonding process, a flexible mechanism for implementing convex for die bonding to be applied to the bond head is proposed. In addition, modeling of flexible mechanisms, analysis/design/control/evaluation of static/dynamics properties are performed. The proposed system was controlled by capacitive sensor (lion precision, CPL 290), piezo actuator (P-888,91), and dSpace. This flexure mechanism implemented a working range of 200 ㎛, resolution(3σ) of 7.276nm, Inposition(3σ) of 3.503nm, settling time(2%) of 500.133ms by applying a reverse bridge type mechanism and leaf spring guide, and at the same time realized a maximum step difference of 6 ㎛ between die edge and center. The results of this study are applied to the D2W hybrid bonding process and are expected to bring about an effect of increasing semiconductor yield through void removal. In addition, it is expected that it can be utilized as a system that meets the convex variable amount required for each device by adjusting the elongation amount of the piezo actuator coupled to the flexible mechanism in a precise unit.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.1
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• pp.75-83
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• 2004

In Korea the number of forest fire occurrence and its damaged area have increased drastically and the plans for afforestation such as sound erosion control restoration and forestation have performed to restore for forest fire damaged area. In this study fire resistant forest was developed by selecting fire resistance tree species and applying GIS analysis, considering the characteristic of forest fire and location environment in forest fire damaged area along the east coast. Moreover, it showed the possibility of how spatial information technology such as virtual GIS could be applied during restoring forest fire damaged area and approaching landscape ecology researches. Especially the fire resistant forest was established by using GIS analysis against large scaled forest fires then the best forest arrangement was performed through this fire resistant forest species and 3D modeling in study area. In addition, the forest landscape was established through site index on passing years and then 3D topography and tracking simulation, which is very similar to real world, were constructed by using virtual GIS.

• Archives of design research
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• v.14 no.1
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• pp.63-70
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• 2001

Thanks to the inter-connection of information servers throughout the world based on the internet technology, the new sphere which actual transaction can be made like in the visible market has become conspicuous as the virtual space. The movement to realize the new business through the cyber space has been actively ongoing. In the domestic market, a lot of corporations knowing the needs of internet shopping malls have entered into this e-business but they have not made a big success comparing with internet's potentials. And, it can be attributed to the simple planes and the limitations of information provided by the cyber malls, which means that the needs of better information transfer we apparent Accordingly, in this thesis, the research on the 3-D based products and shopping malls has been made through the inter-complementary composition between the 2-D shopping malls and 3-B ones. This research consists of 3 parts. Firstly, through the research on references and existing data, it presents the analysis on consumer's characteristics and sales limits of the internet shopping mall's products. Secondly, the background of 3-D shopping mall's advent and the virtual reality technology data are put together. Finally, it presents how the development of 3-D based product modeling and shopping malls can increase the consumer's purchase power and furthermore the directions of shopping malls to go.

• Journal of Power System Engineering
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• v.16 no.6
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• pp.52-58
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• 2012

Roll forming process is one of the most widely used processes in the world for forming metals such as a furniture drawer guide or an up and down slide guide. It can manufacture goods of the uniform cross section on a large scale throughout the continuous processing. In the domestic design and manufacture, roll forming process for production is taking most of the method of 2-point under rail slide. However, this method is vulnerable to the structural strength and stiffness is not suitable for high load conditions. Therefore, through systematic study of high load, low noise 3-point ball type of under rail slide its own design and manufacturing technology is the need to build. In this paper, to make center member of 3-point ball-type under rail slide for the refrigerator doors, the roll forming modeling and simulation are performed. Tensile test is performed about SCP-1 1/2H for determine the mechanical properties of materials. Modeling and simulation of roll forming is used MSC.MARC software of a dedicated analysis program used by rigid plastic finite element method. Interference between the roll and the final shape are predicted from the results of the simulation.

• Journal of KIBIM
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• v.12 no.4
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• pp.70-79
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• 2022

As BIM(Building Information Modeling) technology advances in architecture around the world, projects and industries using BIM are increasing. Unlike previous developments that were limited to buildings, BIM is now spreading to other fields such as civil engineering and electricity. In architecture, BIM is used in the entire process from design to maintenance of a building, and IFC(Industry Foundation Classes), a neutral format with interoperability, is used as an open BIM format. Since firefighting requires intuitive 3D models for evacuation and fire simulations, BIM models are desirable. However, due to the BIM model, which was developed centered on building objects, there are no objects and specific properties for fire evacuation in the IFC scheme. Therefore, in this study, when adding a new object in the firefighting area to the IFC schema, the IFC interoperability is not broken and the building WBS(Work Breakdown Structure) is analyzed with a hierarchical system similar to the IFC format to define the scope for a new object and the firefighting part within of the building WBS to derive a firefighting HBS(Hierarchy Breakdown Structure) with the extension of the object-oriented IFC file. And according to HBS, we propose an IFC schema extension method. It is a methodology that allows BIM users to instantly adapt the IFC schema to their needs. Accordingly, the methodology derived from this study is expected to be expanded in various areas to minimize information loss from IFC. In the future, we will apply the IFC extension methodology to the actual development process using HBS to verify that it is actually applicable within the IFC schema.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4170-4175
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• 2015

The global warming has been recognized as a serious problem. To solve this problem, the country of all the world have conducted techniques such as energy saving and reduction of greenhouse gas. The 30% of total energy is being consumed by buildings domestically and BAS/BEMS are being operated for the management of building energy. But, BEMS is unsatisfactory condition to manage the energy efficiently. In this study, We investigate real application on Chamsaem elementary school as a target buildings and develop 3D Web Browser platform. The spatial information of target buildings is described with used BIM and the energy information is presented for facilities operation and electricity consumption in floor and facility. We perform the quantitative evaluation based on ISO/IEC 9126 and operate this system for two months. in result, energy decreased by about 16%. We expect that the proposed 3D Web Browser system will bring operating efficiency improvement of the current BEMS.