• Journal of the Korean Geophysical Society
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• v.3 no.2
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• pp.127-138
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• 2000

This study was conducted to examine the differences between dynamic and static elastic constants by use of some laboratory tests of cement mortar specimens which have different water/cement mixing ratios. Specific gravity measurement, ultrasonic velocity estimating and uniaxial compression test were adopted to acquire the dynamic and static elastic constants. Digital data acquisition and processing enhanced the accuracy of estimating the velocities of specimens drastically, Also, the method using the gradient of propagation delay time in according to increment of specimen length more enhanced the accuracy than the method using the only one specimen length over total propagation time. The correlation between density and the P and S wave velocity of specimens shows reliable positive relation and the correlation between density and the strength of uniaxial compression has the similar relationship. The dynamic Young's modulus $(E_D)$ is alway greater than the static Young's modulus $(E_S)$ and there is increasing tendency of the ratio $(E_D/E_S)$ according to the increase of density or strength of the specimens. On the other hand, there is no typical relationship between dynamic Poisson's ratio $({\nu}_D)$ and static Poisson's ratio $({\nu}_S)$ and just the ratio of ${\nu}_D/{\nu}_S$ ranges front 69 to 122 %.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.436-438
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• 2022

National Research Data Commons aims to build a system that can be used jointly by arranging analysis resources such as computing infrastructure, software, toolkit, API, and services used for data analysis together with research data to maximize the use of research data. do. The sharing and utilization system for publications and research data in the R&D process is well known. However, the environment in which data and tightly coupled software and computing infrastructure can be shared and utilized is insignificant and there is no management system. In this study, a data model is designed to systematically manage information on digital research resources required in the data-oriented R&D research process. This will be used to register and manage digital research resource information in the National Research Data Commons Service.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.45-51
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• 2005

This paper emphasizes on the accomplishment of compensated proton density image and T2 weighted image taken from the shrinkage surface of the Brain. From the images, the Brain's surface shrinkage in the normal image and the surface shrinkage in the abnormal image can be observed. After the separation of white matter, gray matter, and CSF, this algorithm calculates the volume of each of them automatically. Results are subdivided into particular ages and saved in the database to be analyzed and to be processed statistically. Therefore, by using this algorithm the normal and abnormal stages can be detected in the early stages to diagnose. This result easily discernment Alzheimer patient and is useful for Alzheimer diagnostic and early detection.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.351-359
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• 2015

This convergence study analyzed the effectiveness of digital radiography system of copper(Cu) filter in the added filtration for the removal of lower energy radiation through dose and image evaluation. We were analyzed from April to June 2015 result of the examination. Cu filter was applied to each non, 0.1, 0.2, 0.3 mm according to change of kV and mAs and doses were evaluated. Image quality was evaluated by PSNR, MAE, MSE, CNR, SNR and qualitative analysis was performed by seven items for resolution and contrast from chest x-ray criteria of national cancer checkup. The absorbed doses with Cu were lowered by 16-88 % than non-filter but the gaps decreased as kV increased. PSNR were over 30 dB and all significant and CNR and SNR were superior with non-filter but in the qualitative analysis, there were different statistical significant according to each item. The score of 0.1 mm filter was high at pulmonary blood vessel observation and in the 0.3 mm Cu, there were no statistical signigicant except high density and full of air portion. Cu filter can improve image quality with lower radiation dose using better radiation quality and correction power at digital radiography system.

• Composites Research
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• v.17 no.6
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• pp.28-36
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• 2004

Micro-tow deformation during forming of PVC foam-fabric composite sandwich structure is investigated to find out the correlation between forming condition and material deformation. The foams used in this research are PVC foams which have 4 different densities and the fabric composite is Carbon/epoxy prepreg which is plain weave (3k) as a skin material. Tow parameters such as crimp angle and tow amplitude are measured using microscope and a proper image tool and are compared with each other. In order to find out the effect of foam deformation during forming on tow deformation the compressive tests of foams are performed in three different environmental temperatures ($25^{\circ}C$, $80{\circ}C$, $125^{\circ}C$). The microscopic observation results show that the micro tow deformations are quite different from each other with respect to the foam density and forming pressure.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.2
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• pp.160-178
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• 2023

Diagnosis and analysis of occlusal relationships are important factors in prosthetic treatment. A thorough occlusion analysis and evaluation should be performed before treatment to restore a stable interocclusal relationship. Analysis and evaluation are essential during the treatment process and at regular follow-ups. Recently, with the development of dental equipment and digital processing methods, new quantitative analysis methods that can record the patient's occlusal relationship have been introduced. Among them, the T-Scan Novus (Tekscan Inc., S. Boston, MA, USA) displays the strength of the initial contact point and the occlusal contact point of the teeth using a pressure sensor. With this, occlusal contact time of the teeth, anteroposterior and left-right balance of occlusal force can be compared. The Dental prescale II (GC Co., Tokyo, Japan) scans the occlusal contact point using a pressure-sensing film and analyzes the density of the contact point. It can measure the distribution and strength of the occlusal force of the teeth in the most natural occlusion state. Based on this, appropriate prosthetic treatment (four-unit fixed partial denture, removable partial denture, complete denture, and complete oral restoration cases) was performed according to the area and extent of the patient's tooth loss. The patient's occlusion at the first visit, treatment stage, right after treatment, and regular follow-up were compared and evaluated using a quantitative method for appropriate occlusion analysis using T-Scan Novus and Dental prescale II. This report enhances the understanding of occlusion analysis during prosthetic restoration. The results satisfied both the clinician and patients in terms of function and aesthetics.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.370-370
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• 2017

최근 기후변화와 이상기후의 영향으로 인하여 홍수재해의 시 공간적 패턴은 보다 복잡해지고, 예측이 어려워지고 있다. 이러한 기상이변에 따른 홍수피해를 예방하기 위한 비구조적 대책으로 홍수위험등급 및 범람범위 등의 정보를 포함하고 있는 홍수위험지도의 작성이 필요하다. 실제로 고정밀도 홍수위험지도를 작성하기 위해서는 지형, 지질, 기상 등의 디지털 정보 및 사회 경제와 관련된 다양한 DB를 필요로 하며, 강우-유출-범람해석 모델링을 통해 범람면적 및 침수깊이 등의 정보를 획득하게 된다. 하지만 일부지역, 특히 개발도상국에서는 이러한 계측 홍수 데이터가 부족하거나 획득할 수가 없어 홍수위험지도 제작이 불가능하거나 그 정확도가 매우 낮은 실정이다. 따라서 본 연구에서는 ASTER 또는 SRTM과 같은 범용 DEM 등 지형자료만을 기반으로 한 선형이진분류법(Liner binary classifiers)과 ROC분석(Receiver Operation Characteristics)을 이용하여 미계측 유역 (DB부재 또는 부족으로 강우-유출-범람해석 모델링이 불가능한 북한지역)의 홍수위험지역을 탐지하고, 적용성을 평가하고자 한다. 5개의 단일 지형학적 지수와 6개의 복합 지형학적 지수를 이용하여 Area Under the Curve (AUC)를 계산하고, Sensitivity (민감도)와 Specificity (특이도)가 가장 높은 지수를 선별하여 홍수위험지도를 작성하고, 실제 홍수범람 영상(2007년 북한 함경남도지역 용흥강 홍수)과 비교 분석하였다. 본 연구에서 제시하는 선형이진분류법과 ROC분석 방법은 홍수범람해석을 위한 다양한 기초정보를 필요로 하지 않고, 지형정보만을 사용하기 때문에 관측 데이터가 없거나 부족한 지역에 대해서 우선적으로 홍수위험지역을 탐지하고, 선별하는데 유용할 것으로 판단된다.

• Journal of Broadcast Engineering
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• v.27 no.5
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• pp.751-761
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• 2022

With the development of digital graphics technology, the metaverse has become a significant trend in the content market. The demand for technology that generates high-quality 3D (dimension) models is rapidly increasing. Accordingly, various technical attempts are being made to create high-quality 3D virtual humans represented by digital humans. 3D volumetric capture is spotlighted as a technology that can create a 3D manikin faster and more precisely than the existing 3D model creation method. In this study, we try to analyze 3D high-precision facial production technology based on practical cases of the difficulties in content production and technologies applied in volumetric 3D and 4D model creation. Based on the actual model implementation case through 3D volumetric capture, we considered techniques for 3D virtual human face production and producted a new metahuman using a graphics pipeline for an efficient human facial generation.

• Journal of Digital Convergence
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• v.20 no.3
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• pp.75-83
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• 2022

Korea, which has the highest pedestrian fatality rate among OECD countries, is making efforts to improve the safe walking environment by enacting laws focusing on pedestrian. Spatial clustering was conducted with scan statistics after examining the social network data related to traffic accidents for children and seniors. The word cloud was used to examine people's recognition Campaigns for children and literature survey for seniors were in main concern. Naedang and Yongsan are the regions with the highest relative risk of weak pedestrian for children and seniors. On the contrary, Bongmu and Beomeo are the lowest relative risk region. Naedang-dong and Yongsan-dong of Daegu Metropolitan City were identified as vulnerable areas for pedestrian safety due to the high risk of pedestrian accidents for children and the elderly. This means that the scan statistics are effective in searching for traffic accident risk areas.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.353-366
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• 2015

The purpose of this study was to examine how region-specific characteristics affect the occurrence of cardiac arrest. To analyze, we combined a unique data set including key indicators of health condition and cardiac arrest occurrence at the 244 small administrative districts. Our data came from two main sources in Korea Center For Disease Control and Prevention (KCDC): 2010 Out-of-Hospital Cardiac Arrest Surveillance and Community Health Survey. We analyzed data by using multiple regression, geographically weighted regression and decision tree. Decision tree model is selected as the final model to explain regional variations of cardiac arrest. Factors of regional variations of cardiac arrest occurrence are population density, diagnosis rates of hypertension, stress level, participating screening level, high drinking rate, and smoking rate. Taken as a whole, accounting for geographical variations of health conditions, health behaviors and other socioeconomic factors are important when regionally customized health policy is implemented to decrease the cardiac arrest occurrence.