• The Journal of Korean Academy of Prosthodontics
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• v.51 no.3
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• pp.160-166
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• 2013

Purpose: The purpose of this study was to compare the fracture strength of traditional metal-ceramic crowns and full zirconia crowns according to the occlusal thickness. Materials and methods: A mandibular first molar resin tooth was prepared with 1.5 mm occlusal reduction, 1.0 mm rounded shoulder margin and $6^{\circ}$ taperness in the axial wall. Duplicating the resin tooth, 64 metal dies were fabricated. 48 full zirconia crowns were fabricated using Prettau zirconia blanks by ZIRKONZAHN CAD/CAM and classified into six groups according to the occlusal thickness (0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm). 16 metal-ceramic crowns were fabricated and classified into two groups according to the occlusal porcelain thickness (1.0 mm, 1.5 mm). All crowns were cemented on each metal die and mounted in a universal testing machine. The load was directed at the functional cusp of each specimen until catastrophic failure occurred. One-way ANOVA, Tukey multiple comparison test (${\alpha}=.05$) and t-test (${\alpha}=.05$) were used. Results: The results were as follows. 1. The test 1 group (646.48 N) showed the lowest fracture strength (P<.05), and the value of the test 2.3.4.5 groups (866.40 N, 978.82 N, 1196.82 N, 1222.41 N) increased as thickness increased, but no significant difference were found with the groups (P>.05). The value of test 6 group (1781.24 N) was significantly higher than those of the other groups (P<.05). 2. There were no significant differences of the fracture strength of metal ceramic crowns according to occlusal porcelain thickness 1.0 mm (2515.71 N) and 1.5 mm (3473.31 N) (P<.05). Conclusion: Full zirconia crown needs to be 1.0 mm or over in occlusal thickness for the posterior area to have higher fracture strength than maximum bite force.

• Journal of Internet Computing and Services
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• v.15 no.5
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• pp.25-32
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• 2014

In the current information and knowledge-based society, a nation's economy power heavily depends on IT-related industry and technology. In this sense, most countries are trying to foster IT industry by developing new and innovative IT technologies. Traditionally, only a few talented persons have been leading the whole IT industry. Thus, it is very important and necessary to identify and support the gifted children in IT in early ages for development of IT industry. The purpose of this paper is to investigate study performance of the gifted children in IT for different grades. Our research is focused on especially 4th grade students, 5th grade students, and 6th grade students in elementary schools. Among various abilities of the gifted children in IT, in this paper, we are interested in programming ability and logical thinking ability. To our best knowledge, there is no research work on study performance depending on different grades of the gifted children in IT. For this purpose, the gifted students in gifted science education center attached in a university at Seoul Metropolitan Area are selected and their test scores for 8 years were collected and analyzed. The statistical analysis results show that there is no significant difference among 4th grade students, 5th grade students, and 6th grade students for programming ability and logical thinking ability. We hope that this result can help suggest and propose study contents, curriculum, principles and laws for the gifted education in IT.

• KDI Journal of Economic Policy
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• v.28 no.1
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• pp.95-116
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• 2006

Traditionally, foreign labor inflow into Korea has been rare and, hence, issues on foreign workers did not draw much attention. However, changing economic conditions of the Korean economy, such as "labor-shortage" problem in SMEs in manufacturing sector, has made the Korean government open its door to the foreign workers since the early 1990s through the Industrial Trainee System. The inflow of foreign workers, on the other hand, has generated various social and economic problems, such as substantial increase of illegal over-stayers, illegal utilization of foreign unskilled workers by domestic SMEs, to name a few. Against this background, the Employment Permit System was implemented from 2004. This new system aims at supplying foreign workers to SMEs as well as protecting them as legal 'employees'. In any case, it is very important to understand how and to what extent the inflow of foreign workers have affected the Korean economy in order to establish long-term policy stance. This paper aims to empirically assess the economic impact of foreign workers on domestic workers in the manufacturing sector during 1997~20001, focusing on the Industrial Trainee System. The empirical results of the paper can be summarized as follows. First, there is some evidence that male semi-skilled workers are the group that is likely to have been displaced by industrial trainees. Second, we were unable to find any strong evidence suggesting that the inflow of foreign industrial trainees decreased wages of less-skilled Korean workers.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.231-242
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• 2018

The efficient management of the Length of Stay(LOS) is important in hospital. It is import to reduce medical cost for patients and increase profitability for hospitals. In order to efficiently manage LOS, it is necessary to develop an artificial intelligence-based prediction model that supports hospitals in benchmarking and reduction ways of LOS. In order to develop a predictive model of LOS for acute stroke patients, acute stroke patients were extracted from 2013 and 2014 discharge injury patient data. The data for analysis was classified as 60% for training and 40% for evaluation. In the model development, we used traditional regression technique such as multiple regression analysis method, artificial intelligence technique such as interactive decision tree, neural network technique, and ensemble technique which integrate all. Model evaluation used Root ASE (Absolute error) index. They were 23.7 by multiple regression, 23.7 by interactive decision tree, 22.7 by neural network and 22.7 by esemble technique. As a result of model evaluation, neural network technique which is artificial intelligence technique was found to be superior. Through this, the utility of artificial intelligence has been proved in the development of the prediction LOS model. In the future, it is necessary to continue research on how to utilize artificial intelligence techniques more effectively in the development of LOS prediction model.

• Korea journal of population studies
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• v.20 no.1
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• pp.65-96
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• 1997

The main purpose of this study is to explore the determinants of sex ratio imbalance at birth in Taegu which has experienced the extremely imbalanced sex ratio at birth since mid-1980s. This paper attempts to compare the determinants of sex ratio imbalance at birth, such as sex discrimination against women, son preference, prenatal sex identification followes by sex-selective induced abortions, among married women aged 25 to 44 in Taegu with those in Bay area, California in USA. The research is based on the survey data which were conducted in Taegu, Repulic of Korea and Bay area, California in USA. The findings of this analysis suggest that married women in Taegu are more likely to feel sex discrimination against women than married women in Bay area. Furthermore, the percentage of married women's effort for son bearing before pregnancy is much higher than that of married women in Bay area. We also have found that the percentage of sex-selective induced abortion in Taegu is six times higher than that of married women in Bay area. According to the logistic regression analysis, the determinants of sex-selective induced abortion among married women in Taegu are discrimination against women, son preference, prenatal sex identification. On the other hand, age is the only variable which has an important impact on sex-selective induced abortion among married women in Bay area. From the findings of this study, we can conclude that son preference based on Cofucianism is the most important impact on sex ratio imbalance at birth in Taegu where son preference is much stronger than other regions in Korea. The phenomenon of extremely imbalanced sex ratio at birth in Taegu is the result of combination of these factors, such as strong son preference, seeking to have at least one son within small family size, and prenatal sex identification followed by sex-selective induced abortion.

• Korean Journal of Social Welfare
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• v.39
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• pp.350-373
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• 1999

The patient population of U. S. state mental hospitals has changed drastically since the 1960s, when the deintstitutionalization movement began. This paper is designed to look at what happened to the number of inpatients of state hospitals in California during the last 150 years and, from this, to explore implications for the future of the mental health system in Korea, especially for the viability of mental hospitals. The data had been collected by field research(visits to state hospitals and State Department of Mental Health, and interviews with mental health administrators) and accessing statistical publications and various reports. Since the first state hospital opened in 1851 the statewide inpatient population of individuals who were mentally disabled has grown and peaked at 37,489 in 1959. The number of patients in state hospitals, however, began declining in the early 1960s and was reduced to 10,874 by 1971, and to 4,973 by 1986. As of 1997, there were only 4, 263 inpatients remaining in the state hospital system. This dramatic decrease slowed down somewhat in 1980s and 1990s, but this trend seems irreversible except for the inpatients referred by the court. Now the beds in state hospitals are filled with more and more forensic patients, which constitutes nearly 70% of the total inpatient population. Based on these findings, it is well expected that the number of inpatients of mental hospitals in Korea will also be reduced in a significant way as the community-based mental health care system is gradually replacing the traditional one. Mental hospitals need to introduce more diversified programs for the care of the mentally ill, and concurrently more vigorous aftercare programs are required in the community.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.55-62
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• 2017

The Named Entity Recognition system is a system that recognizes words or phrases with object names such as personal name (PS), place name (LC), and group name (OG) in the document as corresponding object names. Traditional approaches to named entity recognition include statistical-based models that learn models based on hand-crafted features. Recently, it has been proposed to construct the qualities expressing the sentence using models such as deep-learning based Recurrent Neural Networks (RNN) and long-short term memory (LSTM) to solve the problem of sequence labeling. In this research, to improve the performance of the Korean named entity recognition system, we used a hand-crafted feature, part-of-speech tagging information, and pre-built lexicon information to augment features for representing sentence. Experimental results show that the proposed method improves the performance of Korean named entity recognition system. The results of this study are presented through github for future collaborative research with researchers studying Korean Natural Language Processing (NLP) and named entity recognition system.

• Journal of Yeungnam Medical Science
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• v.13 no.1
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• pp.110-115
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• 1996

The ESR is one of the oldest laboratory test still in use. Although it lacks specificity in diagnosis, it can be effective for monitoring disease activity and following-up. The Westergren method is used for reference method, however coefficient of variation has been described 0.8% to 22.9% according to the literature. Since the ESR was invented in 1921, measurement technique has developed and automated measurement is introduced. We analyzed one hundred forty-three patient samples using $SEDIsystem^{TM}$ automated ESR measuring system and compared with modified Westergren and Wintrobe methods. Comparison between $SEDIsystem^{TM}$ and modified Westergren for ESR measurement yields the following regression equation; y = 0.863x - 1.69 (r=0.830), $SEDIsystem^{TM}$ and Wintrobe y = 1.14x - 14.7 (r=0.789), respectively. We repeated measurement to evaluate reliability, results are not significant in statistically. In conclusion, $SEDIsystem^{TM}$ automated ESR measurement correlated with modified Westergren and Wintrobe methods, reveal reliable results after 4 hours and can report rapidly for large samples. Thus, these results indicate that $SEDIsystem^{TM}$ automated ESR measurement may be useful tool for clinical practice.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2100-2108
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• 2015

This study was conducted to examine the effects of a simulation-based learning scenario using standardized respiratory patients regarding emergency care on learning satisfaction, and self efficacy, clinical skill competency of health related department students. A quasi-experimental non-equivalent control group pre-post test design was used. A total of 50 students, 25 students for the experimental group and 25 students for the control group, The experimental group received the 2 educations sessions and 1 evaluation session with 180 minutes for each session. It was implemented in November, 2013. Data were analysed using frequency, ratio and t-test by the SPSS/Win 18.0. The experimental group who had the simulation-based learning scenario using standardized respiratory patients showed significantly higher learning satisfaction and self efficacy, clinical skill competency compared with the control group who had a traditional simulation education. Through this study, simulation-based learning scenario using standardized patients was verified to be an effective teaching method to be grow up on professional competency of health related department students. Also the simulation-based learning scenario using standardized patients should be developed in the various fields.

• Journal of Conservation Science
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• v.38 no.2
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• pp.109-116
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• 2022

This study identified Korean red pine (Pinus densiflora) and exotic pines (Pinus resinosa, Pinus sylvestris) with a similar anatomical structure using a dendro-anatomical method that applied dendrochronology, tracheid length, and uniseriate ray cell size. Korean red pine samples were collected from 13 national parks, while exotic pine samples were secured from two wood importers. Tracheid length was measured by distinguishing earlywood from latewood, and uniseriate ray height and cell number were determined. As the exotic pine tree-ring chronology was consistent with the foreign standard tree-ring chronology and displayed high statistical significance, the country and region where the pine samples had been felled and the exact felling date were confirmed. According to the results, which compared tracheid length and uniseriate ray size, no difference was observed between the Korean red and Russian pines. However, the tracheid length of the Russian pines turned out to be slightly longer than the length of the Korean red pine. Additional research securing a larger number of exotic pines (P.resinosa, P.sylvestris) is required to yield more accurate results in the future.