• Communications of Mathematical Education
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• v.28 no.3
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• pp.353-366
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• 2014

Recently, the widespread usage of 3D-Printing has grown rapidly in popularity and development of a high level technology for 3D-Printing has become more necessary. Given these circumstances, effectively using mathematical knowledge is required. So, we have developed free web tools for 3D-Printing with Sage, for mathematical 3D modeling and have utilized them in college education, and everybody may access and utilize online anywhere at any time. In this paper, we introduce the development of our innovative 3D-Printing environment based on Calculus, Linear Algebra, which form the basis for mathematical modeling, and various 3D objects representing mathematical concept. By this process, our tools show the potential of solving real world problems using what students learn in university mathematics courses.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.3
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• pp.334-341
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• 2015

This paper summarizes the results of an investigation into the environmental factors that have an indirect impact on parts quality, as well as those process variables and modeling information that have a direct impact. The effects of strength, surface hardness, roughness, and accuracy of shape, that is, qualities that users generally need to know, were evaluated with laminating direction experimentally. The 3D printing methods used in this experiment were fused deposition modeling (FDM), stereolithography apparatus (SLA), selective laser sintering (SLS), 3D printing (3DP) and laminated object manufacturing (LOM). The goal was to achieve a high standard of quality control and product quality by optimizing the fabrication process.

• Spatial Information Research
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• v.22 no.6
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• pp.33-43
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• 2014

As the number of people who live indoor space has been increased, the interest in 3D indoor spatial information has been grown. Object-Oriented 3D indoor space modeling including indoor spatial information has performed in level of detail 4, and modeling data is able to be constructed based on various raw data which are as-built drawing, laser scanning, BIM data, and camera. 3D indoor space modeling has been worked based on established indoor space modeling process, and the result can be used for various application fields such as indoor space pedestrian navigation, facility management, disaster management, and so on. However, the modeling process has limitations to perform indoor space modeling efficiently, because the process is complicated and wastes time at modeling work. In this paper, we propose evaluation on practical use of raw data for 3D indoor space modeling purpose on supporting efficient indoor space modeling through analyzing the established process. Therefore, we define the requirements to evaluate the practical use of raw data and propose the verification method. In addition, as-built drawing which has been used in Seoul 3D indoor space modeling project will be applied to proposed method as a raw data.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.2
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• pp.57-65
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• 2008

The improvement of the performance in laser radar simulation requires fast retrievals of the spatial locations and attributes of objects in response to the laser signals of the simulators. Since the data used in simulation are complex 3D objects such as terrain, buildings and vehicles, and are of large sizes, commonly used 3D modeling tools are not suitable for this use. We proposed a method to store such 3D objects in a database, perform required queries and integrate with visualization tools. We showed the processes for the data modeling based on 3D topological concepts and then building a spatial DBMS. Also, we illustrated the process for accessing and visualizing the stored data using VRML and performed test computations using some laser signal data. With further enhancement on data modeling and LOD problems in visualization, the proposed method will be practically applied in different situations including laser simulation.

• Journal of the HCI Society of Korea
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• v.12 no.3
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• pp.13-23
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• 2017

In this paper, we propose a new in-hand 3D modeling system that improves user convenience. Since traditional modeling systems are inconvenient to use, an in-hand modeling system has been studied, where an object is handled by hand. However, there is also a problem that it requires additional equipment or specific constraints to remove hands for good modeling. In this paper, we propose a contact state change detection algorithm for automatic hand removal and improved ICP algorithm that enables outlier handling and additionally uses color for accurate registration. The proposed algorithm enables accurate modeling without additional equipment or any constraints. Through experiments using real data, we show that it is possible to accomplish accurate modeling under the general conditions without any constraint by using the proposed system.

• Journal of Korea Multimedia Society
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• v.13 no.4
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• pp.601-608
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• 2010

This investigation proposes a new method to overcome disadvantages of panorama VR that is oriented toward spacial information and Object VR that is oriented toward object itself and consequently to make 3D virtual reality (VR) contents efficiently by using image based approach. 3D VR contents provide satisfactory qualities to users but 3D modeling is complex and elaborative and requires high cost. So, this paper aims at reducing tremendous efforts for making 3D VR by substituting 3D modeling with 'advanced Billboard'(we call it Smart Billboard). Smart Billboard has a mechanism for selecting an adequate mapping image that is observable at each user viewpoint and carry on texture mapping into the Billboard. And it is validated with the practical embodiments of a virtual museum in which the exhibitions are prepared by Smart Billboard.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1678-1680
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• 2002

Stereo matching technique is used in many practical fields like satellite image analysis and computer vision. In this paper, we suggest a method to extract a target object image from a complicated background. For example, human face image can be extracted from random background. This method can be applied to computer vision such as security system, dressing simulation by use of extracted human face, 3D modeling, and security system. Many researches about stereo matching have been performed. Conventional approaches can be categorized into area-based and feature-based method. In this paper, we start from area-based method and apply area tracking using scanning window. Coarse depth information is used for area merging process using area searching data. Finally, we produce a target object image.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.3
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• pp.300-312
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• 2000

The application areas of embedded real-time systems are very wide and so are the requirements for real-time processing and reliability of the systems. To develop embedded real-time systems effectively with its real-time and reliability properties guaranteed, an appropriate real-time model is needed. Recently, the research on real-time object-oriented model is active, which graft the concept of object-orientation on real-time systems modeling and development. In this paper, we propose dRTO (dependable Real-Time Object) model, with 5 primitive classes. These allow designers to effectively model the characteristics of real-time systems, i.e., object-orientation, real-time-ness and dependability. The dRTO model has three main features. First, it is able to model and implement the timing constraints imposed on real-time objects as well as interactions among the objects. Second, hardware and software components (including kernel) of embedded systems can be modeled in one frame. Third, it is able to represent fault detection and recovery mechanisms explicitly.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.5
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• pp.537-542
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• 2011

A mirror neuron is a neuron fires both when an animal acts and when the animal observes the same action performed by another. We propose a method of 3D reconstruction for occluded object motion tracking like Mirror Neuron System to fire in hidden condition. For modeling system that intention recognition through fire effect like Mirror Neuron System, we calculate depth information using stereo image from a stereo camera and reconstruct three dimension data. Movement direction of object is estimated by optical flow with three-dimensional image data created by three dimension reconstruction. For three dimension reconstruction that enables tracing occluded part, first, picture data was get by stereo camera. Result of optical flow is made be robust to noise by the kalman filter estimation algorithm. Image data is saved as history from reconstructed three dimension image through motion tracking of object. When whole or some part of object is disappeared form stereo camera by other objects, it is restored to bring image date form history of saved past image and track motion of object.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.145-154
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• 2009

For developing an Automation equipment in construction, it is a key issue to develop 3D modeling technology which can be used for automatically recognizing environmental objects. Recently, for the development of "Intelligent Excavating System(IES), a research developing the real-time 3D terrain modeling technology has been implemented from 2006 in Korea and a stereo vision system is selected as the optimum technology. However, as a result of performance tests implemented in various earth moving environment, the 3D images obtained by stereo vision included considerable noise. Therefore, in this study, for getting rid of the noise which is necessarily generated in stereo image matching, the noise elimination algorithm of stereo-vision images for 3D terrain modeling was developed. The consequence of this study is expected to be applicable in developing an automation equipments which are used in field environment.