• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.5
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• pp.229-237
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• 2019

For maintaining high visibility of lane, the high refractive index glass beads with excellent retro-reflectivity are usually applied on the road marking paint. The retro-reflectivity standard of general road marking is different in each country; it is defined as $240mcd/m^2{\cdot}lux$ based on white light in Korea and $250{\sim}300mcd/m^2{\cdot}lux$ in developed countries. In this paper, the recent trends on the manufacturing technology of glass beads suitable for autonomous driving age as well as the road marking regulations has been reviewed. Also, in preparation for the commercialization of autonomous vehicles in the future, the necessity of raising the standard value and improving the glass bead properties were proposed.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.45-45
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• 2023

본 연구에서는 도시 내 및 주변 지역을 대상으로 기상학적 가뭄 발생 여부에 따른 토양수분량 변화 정도를 파악하고, 그에 따른 열섬 현상의 변동 정도를 분석·평가하였다. 먼저, 대상 지역 내 기상학적 가뭄의 시공간적 특성을 분석하기 위해 인공위성, 재분석 자료 및 지상 관측 정보를 활용하여 SPI (Standard Precipitation Index)와 SPEI (Standard Precipitation Evapotranspiration Index) 등 두 가지의 가뭄 지수를 산정하였다. 또한, ERA5 (The Fifth Generation ECMWF Atmospheric Reanalysis)와 GLDAS (Global Land Data Assimilation System) 등의 재분석 자료 및 지상 관측 정보를 활용하여 토양수분 자료 및 기타 기상 관련 주요 정보들을 얻고, 이를 ENVI-met 모형의 초기 입력자료로 고려하였다. 다양한 시나리오 기반의 모의 결과들을 바탕으로 복합 재난의 관점에서 가뭄-토양수분량-열섬 간의 연관성을 분석하고, 주요 영향 인자 및 극한 사상 유발 조건 등에 대한 정보를 파악하였다.

• The Journal of Engineering Geology
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• v.18 no.1
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• pp.45-54
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• 2008

Based on the data obtained from field investigation and soil testing to slope hazards occurrence section and non-occurrence section in gneiss area, a prediction technique was developed by the use of a decision tree model, which is one of the statistical analysis methods. The slope hazards data of Seoul and Kyonggi Province, which were induced by heavy rainfall in 1998, were 104 sections in gneiss area. The number of data applied in developing prediction model was 61 sections except a vacant value. Among these data, the number of data occurred slope hazards was 34 sections and the number of data non-occurred slope hazards was 27 sections. The statistical analyses using the decision tree model were applied to chi-square statistics, gini index and entrophy index. As the results of analyses, a slope angle, a degree of saturation and an elevation were selected as the classification standard. The prediction model of decision tree using entrophy index is most likely accurate. The classification standard of the selected prediction model is composed of the slope angle, the degree of saturation and the elevation from the first choice stage. The classification standard values of the slope angle, the degree of saturation and elevation are $17.9^{\circ}$, 52.1% and 320 m, respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.5
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• pp.20-28
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• 2016

A Ubiquitous City (U-city, Smart City) is one that ties information communications technologies (ICT) into many facets of city construction, thereby implicitly intending to function as a smart city that aims to be efficiently managed as well as provide an enhanced standard of living for its residents. Laws related to the construction of such ubiquitous cities point to integrated city management centers, intelligent facilities, and U-City infrastructure, among others, as central components of U-Cities, but do not provide a standard for these structures. Consequently, building of U-Cities by local governments are based on arbitrary judgments constrained the myriad of practical limitations that they face. Such ambiguity brings to light the need to find ways to improve the quality of these efforts. The first and second stages of this research examine the status of the components of a U-City -ubiquitous planning, technology, infrastructure, and services - and undertakes a comprehensive review thereof, with evaluation criteria formulated on the characteristics of stability, connectivity, goal-orientation, and development potential. In the research's third stage, a realistic and detailed evaluation index by which U-Cities can be renewed, demonstrated, and applied (???) is introduced in a step-by-step fashion, which will allow for local governments to properly assess the standard of their U-City in relation to the realities of the locality. Through the research result, it is expected that the index will become a part of the continued development and advancement of the "smart" character of an autonomous U-City at the local scale, and contribute to the overall revitalization of the U-City.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.1
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• pp.149-159
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• 1999

Purpose: The purpose of this study was to evaluate cervical lymph node metastasis of oral squamous cell carcinoma patients by MRI film and neural network system. Materials and Methods: The oral squamous cell carcinoma patients(21 patients. 59 lymph nodes) who have visited SNU hospital and been taken by MRI. were included in this study. Neck dissection operations were done and all of the cervical lymph nodes were confirmed with biopsy. In MR images. each lymph node were evaluated by using 6 MR imaging criteria(size. roundness. heterogeneity. rim enhancement. central necrosis, grouping) respectively. Positive predictive value. negative predictive value. and accuracy of each MR imaging criteria were calculated. At neural network system. the layers of neural network system consisted of 10 input layer units. 10 hidden layer units and 1 output layer unit. 6 MR imaging criteria previously described and 4 MR imaging criteria (site I-node level II and submandibular area. site II-other node level. shape I-oval. shape II-bean) were included for input layer units. The training files were made of 39 lymph nodes(24 metastatic lymph nodes. 10 non-metastatic lymph nodes) and the testing files were made of other 20 lymph nodes(10 metastatic lymph nodes. 10 non-metastatic lymph nodes). The neural network system was trained with training files and the output level (metastatic index) of testing files were acquired. Diagnosis was decided according to 4 different standard metastatic index-68. 78. 88. 98 respectively and positive predictive values. negative predictive values and accuracy of each standard metastatic index were calculated. Results: In the diagnosis of using single MR imaging criteria. the rim enhancement criteria had highest positive predictive value (0.95) and the size criteria had highest negative predictive value (0.77). In the diagnosis of using single MR imaging criteria. the highest accurate criteria was heterogeneity (accuracy: 0.81) and the lowest one was central necrosis (accuracy: 0.59). In the diagnosis of using neural network systems. the highest accurate standard metastatic index was 78. and that time. the accuracy was 0.90. Neural network system was more accurate than any other single MR imaging criteria in evaluating cervical lymph node metastasis. Conclusion: Neural network system has been shown to be more useful than any other single MR imaging criteria. In future. Neural network system will be powerful aiding tool in evaluating cervical node metastasis.

• Journal of radiological science and technology
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• v.31 no.4
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• pp.347-353
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• 2008

This study is to prepare an evaluation standard about personal information protection and security management of a medical institution and to build up a grade standard of evaluation in PACS environment. We built up evaluation index based on 10 detailed items in four big categories (political security, technical security, data management security and physical security) by referring to ISO17799 (BS 7799), HIPPA (Health Insurance and Portability and Accountability Act of 1996) and domestic medical law. We have investigated at the thirty places where medical facility with the extracted security criteria and security evaluation index. Average score of physical security list, one of the big categories, was 18.5/20 (93%) at all medical institutions. Political security score was 18.5/30 (62%), data management security score was 12/20 (60%) and technical security score was 17.5/30 (58%). Therefore, security evaluation score was average 67 in 30 general hospitals, which was 4th level. The results showed that it is necessary to establish evaluation and management standard about personal information protection and security consciousness which are weak in PACS environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.765-771
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• 2010

This study was carried out to examine relationships between financial pressures, depression, the quality of life related with economic stress factors on patients suffering from chronic strokes residing in Daejeon. 209 patients with chronic stroke being treated in genernal hospital were selected as subjects for this study. Data were collected by conducting 1:1 interviews through questionnaires. The study examined differences in patients' economic stress, depression, standard of living and the quality of lives through collected data. The results showed statistically meaningful analysis in standard of living(p<.000), economic pressure (p<.000), depression (p<.05), the quality of life (p>.05), the standard of living (p<.05). The higher the economic pressure, depression indexes or very severe the standard of living the lower the quality of life index, so the economic stress meaningfully increases. If an objective economic stress index is devised by measuring the level of economic burdens in common with guardians of patients and patients themselves, the index will become clinically important data. Furthermore, there requires the development of medical mediation that can reduce economic stress and increase the quality of life for patients suffering from strokes.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.1
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• pp.15-21
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• 2010

Previously standardization study for identifying 5 types of pattern identification of stroke patients has been performed and the Korean standard of pattern identification (II) was developed. In the present study we investigated the interactions between total indices designated by the Korean standard of pattern identification(KSPI II) and indices for PI of Cold-Heat and Deficiency-Excess. Indicators for Cold-Heat and Deficiency-Excess are isolated from 58 indices through the survey of oriental medicine doctors and their relationship with KSPI-II indices was analyzed by corresponding analysis method using data of 1581 stroke patients. Means and standard deviations indicated that 2 Cold indices, 14 Heat indices, 12 Deficiency indices, and 5 Excess indices were included for Cold-Heat and Deficiency-Excess pattern identification. The results of corresponding analysis shows the relationship of 57 indices and 4 types of pattern identification (excluding 1 index and 1 pattern among 58 indices and 5 patterns) using the cross-tabulation which was obtained from the clinical data. Most of Cold and Heat index were divided to dimension 1(inertia 51.9%) obtained from the result of corresponding analysis. Deficiency and Excess index were partially associated with dimension 2(inertia 31.7%). These data suggest that pattern identification of Cold-Heat plays an role in the standardization of pattern identification in stroke, although further studies are required by various trials such as analysis of surveys and clinical data.

• Journal of the Korean Geotechnical Society
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• v.37 no.6
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• pp.29-37
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• 2021

Since many geotechnical structures are constructed on a weathered granite layer, it is important to evaluate their characteristics. As a seismic design is the more important nowadays, the demands to estimate a shear wave velocity (V_S) based on acceptable methods are increasing. In this study, an empirical equation predicting V_S of the weathered granite layer is suggested based on the nonlinear multiple variable regression analysis whose independent variables are both SPT (Standard penetration test)-N₆₀ and chemical weathering index. It is concluded that the accuracy of the empirical equation estimating V_S of the weathered granite layer increases when it considers the chemical weathering index as an additional independent variable compared to the result of simple regression analysis using only N₆₀.

• Journal of the Korean Dietetic Association
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• v.2 no.2
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• pp.168-180
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• 1996

This study was accomplished to investigate the prevalence of obesity among the 229 elementary school children(boys; 115 persons, girls; 114 persons) during 4 years by retrospective study. The results were as follows; 1. The mean height and weight of 229 subjects were 143.2cm(boys;143.4cm, girls; 142.7cm), 38.8kg(boys;40.4kg, girls;36.9kg), respectively. And other anthropometric body index such as the mean BMI, Rohrer Index, WLI and Obesity Index of subjects were 18.8(boys;19.5, girls; 18.0), 1.31(boys;1.36, girls; 1.26), 115.5(boys;121.4, girls; 108.9) and 110.6(boys;114.5, girls; 106.7), respectively. 2. The mean percentile values of height and weight of subjects were higher than the '85 Korean Children's Growth Standard, respectively. In the case of boys, the 75th percentile value of weights was larger than that's 97th's. And in the case of girls, the 75th percentile value of weights was equalled to the that's 90th's. 3. When the subjects were classified into 4 groups such as obese, overweight, normal, and lean groups according to Obesity Index, their percentages were 28.8%(boys; 38.3%, girls; 19.3%), ll.8%(boys; 9.6%, girls; 14.0%), 50.7%(boys; 47.0%, girls; 54.4%) and 8.7%(boys; 5.2%, girls; 12.3%), respectively. And only I person(3.3%) is classified into normal group and 2 persons(6.7%) are classified into overweight group when they become 5 grade among 30 persons(13.1%) who were classified into obese group when they were I grade. 4. Changes in percentage of subjects differentiated by 3 indices during 4 years(from I grade to 5 grade) were as follows; In the case of BMI were 5.2%, 5.2%, 11.8%, 21.0%, 27.5%. In the case of Roher index were 13.1%, 11.8%, 14.4%, 14.8%, 17.8%. And in the case of WLI were 15.7%, 21.6%, 29.5%, 32.2%, 36.7%. 5. There was no significant difference among 4 groups on the skip rate of breakfast(obese;48.5%, overweight;55. mean meal time of subjects took about 10 minutes which was short, and the eating rate of obese group was significantly shorter than that of other groups(p<0.05). There was a tendency that the rate of the obese or overweight group eating together in breakfast and dinner was lower than that of normal or lean group. The mean T.V. watching time and the rate of eating out of subjects were 1-2 hours/day and 1 or 2 times/week. In conclusion, the subjects have been grown remarkably compared to the '85 Korean Children's Growth Standard, especially boy's weight. In order to the elementary school children to be grew as healthful citizen they should recognize the importance of meals of everyday, the balanced meals, and desirable eating habits. In addition to these, we should educate the ways of meal-life to them. We also are in need to develope the methods of education for the students themselves and their parents so that could prevent the increase rate of obesity.