• Journal of Biomedical Engineering Research
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• v.41 no.5
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• pp.195-202
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• 2020

Needle detection in ultrasound images is sometimes difficult due to obstruction of fat tissues. Accurate needle detection using continuous ultrasound (CUS) images is a vital stage of treatment planning for tissue biopsy and brachytherapy. The main goal of the study is classified into two categories. First, new detection model, i.e. D-Attention Unet, is developed by combining the context information of 3D medical data and CUS images. Second, the D-Attention Unet model was compared with other models to verify its usefulness for needle detection in continuous ultrasound images. The continuous needle images taken with ultrasonic waves were converted into still images for dataset to evaluate the performance of the D-Attention Unet. The dataset was used for training and testing. Based on the results, the proposed D-Attention Unet model showed the better performance than other 3 models (Unet, D-Unet and Attention Unet), with Dice Similarity Coefficient (DSC), Recall and Precision at 71.9%, 70.6% and 73.7%, respectively. In conclusion, the D-Attention Unet model provides accurate needle detection for US-guided biopsy or brachytherapy, facilitating the clinical workflow. Especially, this kind of research is enthusiastically being performed on how to add image processing techniques to learning techniques. Thus, the proposed method is applied in this manner, it will be more effective technique than before.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.19 no.1
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• pp.47-56
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• 2015

In this paper, we present an implicit method for reconstructing a 3D solid model from two 2D cross section images. The proposed method is based on the Cahn-Hilliard model for the image inpainting. Image inpainting is the process of reconstructing lost parts of images based on information from neighboring areas. We treat the empty region between the two cross sections as inpainting region and use two cross sections as neighboring information. We initialize the empty region by the linear interpolation. We perform numerical experiments demonstrating that our proposed method can generate a smooth 3D solid model from two cross section data.

• Tunnel and Underground Space
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• v.30 no.1
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• pp.39-62
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• 2020

In this study, Barcelona Basic Model (BBM) was implemented into TOUGH2-MP/FLAC3D for the numerical analysis of coupled thermo-hydro-mechanical (THM) behavior of unsaturated soils and the prediction of long-term behaviors. Similar to the methodology described in a previous study for the implementation of BBM into TOUGH-FLAC, the User Defined Model (UDM) of FLAC based on the Modified Cam Clay Model (MCCM) and the FISH function of FLAC3D were used to extend the existing MCCM module in FLAC3D for the implementation of BBM into TOUGH2-MP/FLAC3D. In the developed BBM module in TOUGH2-MP/FLAC3D, the plastic strains due to change in suction increase (SI) in addition to mean effective stress are calculated. In addition to loading-collapse (LC) yield surface, suction increase (SI) yield surface is changed by hardening rules in the developed BBM module. Several numerical simulations were conducted to verify and validate the implementation of BBM: using an example presented in the FLAC3D manual for the standard MCCM, simulation results using COMSOL, and experimental data presented in SKB Reports. In addition, the developed BBM analysis module was validated by simultaneously performing a series of modeling tests that were performed for the validation of the Quick tools developed for the purpose of effectively deriving BBM parameters, and by comparing the Quick tools and Code_Bright results reported in a previous study.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1349-1365
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• 2020

In recent years, in the fields of smart cities and digital twins, research on model generation is increasing due to the advantage of acquiring actual 3D coordinates by using point clouds. In addition, there is an increasing demand for a solid model that can easily modify the shape and texture of the building. In this paper, we propose a method to create a clustered solid building model based on point cloud data. The proposed method consists of five steps. Accordingly, in this paper, we propose a method to create a clustered solid building model based on point cloud data. The proposed method consists of five steps. In the first step, the ground points were removed through the planarity analysis of the point cloud. In the second step, building area was extracted from the ground removed point cloud. In the third step, detailed structural area of the buildings was extracted. In the fourth step, the shape of 3D building models with 3D coordinate information added to the extracted area was created. In the last step, a 3D building solid model was created by giving texture to the building model shape. In order to verify the proposed method, we experimented using point clouds extracted from unmanned aerial vehicle images using commercial software. As a result, 3D building shapes with a position error of about 1m compared to the point cloud was created for all buildings with a certain height or higher. In addition, it was confirmed that 3D models on which texturing was performed having a resolution of less than twice the resolution of the original image was generated.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1069-1072
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• 1987

In this paper, we drive useful data from 3-D depth information as input using discontinuity boundary or clustering. And using magnitude and direction of z-gradient we classify the data into adaptable primitive types through intrinsic and stochastical processing. After these processing information is reconstructed for forming data base. And make relationship and standard view position for matching.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.61.6-61
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• 2001

In this paper, we propose a method to analyze measured data from 3D Laser tracking system and to enhance precision performance of a Cartesian robot. Position data are obtained over the stroke of a Cartesian robot with variable speeds. The measured data is need to model errors with several different sources. In general, the error is a function of part accuracy, assembly accuracy, temperature, and control etc. After the sources of errors are identified, they are used to enhance precision performance. The proposed method is more complete than others because we use very accurate 3D Laser tracking system.

• Korean Journal of Computational Design and Engineering
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• v.11 no.6
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• pp.412-421
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• 2006

Recently, the needs for sharing and exchanging drawing information between 2D and 3D data in complex facilities are well recognized throughout the construction industries. The purpose of this study is to propose an information framework to represent 3D IFC (Industry Foundation Classes) -based drawing of building services in complex facilities as 2D drawing. In this study, 1) attributes of building service objects which are used in 3D CAD system are analyzed and present drawing standards are analyzed, 2) based on the analysis, an information framework is developed to represent 3D model in 2D representation, and 3) further more, to test a compatibility of the information sharing framework, number of standardized APIs and an IFC2Dbrowser are developed during the study.

• Korean Journal of Construction Engineering and Management
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• v.9 no.3
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• pp.85-94
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• 2008

The process of construction industry basically consists of many complicated phase, such as planning, design, construction, MO&R(Maintenance, Operation, and Repair), and deconstruction. And various participants communicate each other during every phase of process. Since construction components have become more complex and diverse recently, many researches on how to exchange and standardization of building. However, in Korea research on IFC(Industry Foundation Classes) which is a standard for international data exchange have been conducted with only study limited Issues, such as studies on the development of 2D extension model for IFC, researches on 3D or 4D based IFC extension, and etc. This stuff covers tests of the compatibility among commercial 3D CAD programs using IFC file format. Several problems of the current IFC model are retrieved as a result.

• Proceedings of Korean Society of Archives and Records Management
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• 2019.05a
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• pp.43-47
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• 2019

In the field of cultural heritage, for the purpose of its preservation and restoration, cultural heritage has been recorded using three-dimensional (3D) digital technology. However, these 3D digital records are a large-scale digital record produced through complicated steps from point cloud data acquisition to 3D model production, and long-term preservation problems cannot be avoided. With international discussions are ongoing, this study looks into the preservation direction of the cultural heritage 3D digital records based on precedent research and case analysis.

• Journal of Korean society of Dental Hygiene
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• v.19 no.6
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• pp.1067-1075
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• 2019

Objectives: The present study aimed to compare the accuracy of removable partial denture (RPD) frameworks fabricated by selective laser sintering (SLS) before and after electropolishing. Methods: A partially edentulous mandibular model was used as the working model. Scanning of the model was performed using a dental scanner. The framework was designed using CAD software. The metal framework was formed using an SLS 3D printer. 3D scans of the two fabricated prototypes produced before and after electropolishing were overlapped with reference data. The fit was calculated based on Root Mean Square (RMS). Fabrication accuracy was verified using the paired t-test to compare the discrepancy before and after electropolishing. Results: The mean (SD) values of RMS before and after electropolishing were 126.6 (34.19) and 75.86 (21.36), respectively. There was a statistically significant difference before and after electropolishing (p<0.05). Conclusions: Metal frameworks made with SLS 3D printers showed clinically acceptable fit after electropolishing.