• Restorative Dentistry and Endodontics
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• v.23 no.2
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• pp.682-689
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• 1998

The purpose of this study was to evaluate the sealing ability of the Microseal$^{(R)}$, which was new obturation system made by Tycom company, U.S.A. Forty-five extracted single-rooted human teeth were resected at cemento-enamel junction and divided three groups. All canals were prepared using Profile system, and then each group was obturated by lateral condensation technique (group 1), vertical condensation technique (group 2) and Microseal$^{(R)}$ condensation technique (group 3) with root canal sealer. Teeth were immersed in resorcinol-formaldehyde resin for 5 days at $4^{\circ}C$ and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were resected horizontally at 1 mm (level I), 2 mm (level II), 3 mm (level III) from the anatomical root apex using low speed microtome and examined with Image analyzer (IBASR, Zeiss co., Germany.) at ${\times}25$ magnification. The gab between the canal wall and the filling material, which was filled with the resin, was measured at each of the three levels. Each ratio of leakage was expressed percentage by calculating the ratio of the area of the resin to the total area of the canal and was analyzed statistically (one-way ANOVA). The results were as follows; 1. The mean ratio of leakage (%) was 6.46% at group 1, 3.06% at group 2, 11.27% at group 3. 2. When evaluating the ratio of leakage at the three levels, there was level I> level II> level III in all groups. Especially, the difference between level I and level III was statistically significant (p<0.05). 3. When evaluating the ratio of leakage at the three groups, there was group 3> group 1> group 2 at all levels. Especially the difference between group 2 and group 3 was statistically significant (p<0.05).

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.3
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• pp.207-215
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• 1993

In order to statistically predict $O_3$ levels in Seoul, the study used the TMS (telemeted air monitoring system) data from the Department of Environment, which have monitored at 20 sites in 1989 and 1990. Each data in each site was characterized by 6 major criteria pollutants ($SO_2, TSP, CO, NO_2, THC, and O_3$) and 2 meteorological parameters, such as wind speed and wind direction. To select proper variables and to determine each pollutant's behavior, univariate statistical analyses were extensively studied in the beginning, and then various applied statistical techniques like cluster analysis, regression analysis, and expert system have been intensively examined. For the initial study of high level $O_3$ prediction, the raw data set in each site was separated into 2 group based on 60 ppb $O_3$ level. A hierarchical cluster analysis was applied to classify the group based on 60 ppb $O_3$ into small calsses. Each class in each site has its own pattern. Next, multiple regression for each class was repeatedly applied to determine an $O_3$ prediction submodel and to determine outliers in each class based on a certain level of standardized redisual. Thus, a prediction submodel for each homogeneous class could be obtained. The study was extended to model $O_3$ prediction for both on-time basis and 1-hr after basis. Finally, an expect system was used to build a unified classification rule based on examples of the homogenous classes for all of sites. Thus, a concept of high level $O_3$ prediction model was developed for one of $O_3$ alert systems.

• International Journal of Railway
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• v.3 no.3
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• pp.106-112
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• 2010

Accidents at level crossing have large portion on train accidents, and causes economical loss by train delay and operational interruption. Various safety equipments are employed to reduce the accident at level crossing, but existing warning device, and crossing barrier are simple train-oriented protection equipments. In this paper, intelligent railway level crossing system is proposed to prevent and reduce accidents. For train driver's prompt action, image of level crossing and obstacle warning message are continuously provided to train driver through wireless communication in level crossing control zone. Obstacle warning messages, which are extracted by computer vision processing of captured image at level crossing, are recognized by train driver through message color, flickering and warning sound. It helps train driver to decide how to take an action. Meanwhile, for vehicle driver's attention, location and speed of approaching train are given to roadside equipments. We identified the effect of proposed system through test installation at Sea train and Airport level crossing of Yeong-dong line.

• Research in Community and Public Health Nursing
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• v.21 no.3
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• pp.282-291
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• 2010

Purpose: The purpose of this study was to analyze the relation between sex perception, sexual life satisfaction, and life satisfaction of the elderly. Methods: The respondents were 227 elders aged over 65. Data were collected from February 10 to December 15, 2007 by interviews and questionnaires. Results: Of the respondents, 18.8% still had sex life and 25.5% wanted to have a date. The main reason to have a date was to relieve loneliness, and the percentage of those who wanted a date was 58.3. The perception level of sex life was 2.27 (men: 2.51, women: 2.14), the satisfaction level of sex life was 2.74 (men: 2.89, women: 2.64), and the level of life satisfaction was 2.98 (men: 3.10, women: 2.92). There was a positive correlation between the perception level of sex life and the satisfaction level of sex life; a positive correlation between the satisfaction level of sex life and the level of life satisfaction; and no correlation between the perception level of sex life and the level of life satisfaction. Conclusion: This study provides a base supporting the usefulness of various nursing intervention programs to enhance the quality of life through making elderly people have a positive perception of sex life.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.500-504
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• 1997

Current source inverter drives of auto sequentially commutated type are very popular in high power applications, because of simple power circuit configuration with four quadrant operation. But the six-step current output create harmonic problems and the input power factor of such a drive is not always good. In this respect pulse width modulated drives using gate turn off thyristors ( GTO ) are finding application, especially in traction drives. However the switching and snubber loses of a GTO do not permit the inverter switching frequency go beyond a few hundred hertz.This will again introduce low frequency harmonic problems. Multi level inverters of the 3-level and 5-level can be considered as an alternative to overcome the low switching frequency harmonic problem of the 2-level GTO inverters. But with multi level inverters the complexity of the power circuit increases. In this paper a combination of multi level ( 2-level and 3-level ) inverters and multi phase induction motor ( 3-phase and 6-phase) configurations are presented for high power VSI drives for traction applications with reduced inverter switching frequency requirements coupled with reduced voltage rating for the power switch.

• Journal of Information Display
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• v.11 no.1
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• pp.21-23
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• 2010

A new level shifter using low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs) for low-power applications is proposed. The proposed level shifter uses a capacitive-coupling effect and can reduce the power consumption owing to its no-short-circuit current. Its power saving over the conventional level shifter is 72% for a 3.3 V input and a 10 V output.

• Journal of applied mathematics & informatics
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• v.11 no.1_2
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• pp.317-326
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• 2003

We classify all possible level Artinian O-sequences of socle degree 5 and type 3. Moreover, we show how to construct level Artinian algebras with those Hilbert functions using the sum of two ideals of finite sets of points in $P^2$ such that the ideal of the union of two sets is level.

• Research in Community and Public Health Nursing
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• v.10 no.2
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• pp.372-386
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• 1999

The purpose of this study was to explore the degree of stress in caregivers caring for CVA patients and the level of daily living performance of CVA patients. The subjects for the study were caregivers of 112 CVA patients who enter a hospital or out-patient-department (OPD) at two Oriental medical hospital in Jeonbuk province. The survey instruments used in this study were Kang's ADL check list for daily living performance of patients and Choi's 4 sore scale for stress of caregivers. The survey was conducted from July 4th to August 30th in 1999. The survey results were analyzed with the Statistical Package for Social Science(SPSS) program and can be summarized as follows: 1. The level of daily living performance for the CVA patients was: 1) complete dependence (M=14.9, 13.1%), 2) complete independence (M=23.6, 20.9%), 3) incomplete independence (M=23.9, 21.0%), 4) incomplete dependence (M=26.6, 25%), 5) dependence and independence (M=23.0, 20.0%). The items for with there was a high level daily living performance were: 1) drinking (M=3.62), 2) eating(M=3.25). 3) position returning (M=3.18) : and the items for which there was a low level of daily living performance were: 1) ascending and descending stairs (M=2.08), 2) walking (M=2.47), 3) dressing and undressing trousers (M=2.55). 2. Degree of caregiver stress was: Mean=2.39 at 40 score. The items for which was a high level caregiver stress were: 1) medical fee (M=3.25), 2) being handicapped or recurrence (M=3.02) : and the items for which there was a low level of caregiver stress were: 1) discontinuity of patient's treatment (M = 1.98). 2) change of home atmosphere caused by patient's disease (M = 1.98), 3) desire of patient's knowing about disease (M= 1.99). 3. There was statistically significant difference in the degree of caregiver stress according to the following caregiver's demographic characteristics: education level (F=3.52, P=0.03). change of caregiver (F=5.41. P=0.02). 4. There was a statistically signifiant difference in the level of daily living performance according to the CVA patients demographic characteristics: patient's paralytic status (F=4.48, P=0.01), duration of disease (t=2.76, P=0.03). 5. There was significant difference in degree of caregiver stress according to the CVA patient's demographic characteristics: CVA status (F=4.75, P=0.01). 6. There was statistically significant difference in the degree of caregiver stress according to the level of daily living performance in CVA patients(r=-0.482, P<0.00).

• Journal of Korean Elementary Science Education
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• v.41 no.4
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• pp.673-689
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• 2022

To understand seasonal changes it is necessary to understand the relationship between celestial bodies in a three-dimensional space, and to this end, modeling activities in which students directly construct, use, evaluate, and modify three-dimensional models are important. In this study, the process of elementary school students using globes and light bulbs to model Earth's motion in a three-dimensional space as a cause of seasonal changes was analyzed. Seventeen sixth graders participated in the modeling process. After exploring phenomena and concepts related to seasonal change, students constructed models using globes and bulbs and used them to explain seasonal changes. Video data recording students' modeling process, students' activity sheets, and transcripts of post-interview were used as research data, and data triangulation was conducted. The modeling level analysis framework was also developed based on previous studies. In particular, the framework was developed in detail in this study in consideration of the concept of Earth's motion as well as understanding model and implementing modeling. In the final analysis framework, the 3D modeling level was classified from level 1 to level 3, and student performance that may appear at each level was specified. As a result of the study, there were two main levels of modeling using globes for elementary school students to explain seasonal changes. The rotation and tilt of the axis of rotation and revolution of the earth were considered but the level at which empirical evidence was not used (level 2), the level at which empirical evidence was used to explain seasonal chages (level 3). However, even when students use empirical evidence, it did not lead to the construction of a scientific model. In this study, the cause was explored in relation to the characteristics of the tool used for modeling.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.3
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• pp.269-281
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• 2012

This study investigates the influence of technology readiness, fashion innovativeness, and participation level perception on the acceptance intention of 3D virtual fitting systems. We presented a 3D virtual fitting system with detailed information that was watched by respondents who subsequently completed a research questionnaire. The data were collected from 300 subjects with an age range of 21 to 39 who have experienced Internet shopping. Descriptive statistics, Cronbach's alpha, factor analysis, correlation analysis, and multiple regression analysis were conducted. The results were as follows. First, fashion innovativeness, technology innovativeness, participation level perception, and optimism significantly influenced the acceptance intention. Second, fashion innovativeness, technology innovativeness, participation level perception, and optimism positively influenced the acceptance intention in the male group; however, technology innovativeness, participation level perception, optimism, and insecurity significantly influenced the acceptance intention in the female group. The results indicated that a marketing strategy has to be designed that focuses on consumers with high technology, fashion innovativeness, and optimism to increase the acceptance intention. In addition, markers have to enhance a participation level perception that will contribute to the introduction of 3D virtual fitting systems. Another notable finding was the importance to differentiate marketing strategies according to gender.