• Restorative Dentistry and Endodontics
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• v.27 no.3
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• pp.249-256
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• 2002

The use of flowable composite resins as liners in class II packable composite restoration has been suggested by some manufacturers. However, the contributions of this technique are unproven. The purpose of this study was to compare the gingival microleakage in class II packable composite restorations with or without the use of flowable composite resins as liners. Slot cavities were prepared on both proximals of 80 extracted human molars and randomly assigned to 8 groups of 20 each. The gingival margins were located at 1mm above CEJ in 80 cavities (group1-4) and 1mm below CEJ in 80 cavities (group5-8). The prepared teeth were mounted in the customized tray with adjacent teeth to simulate clinical conditions and metallic matrix band (Sectional matrix) and wooden wedges were applied. After acid etching and application of Single Bond, each group was restored with the following materials using incremental placement technique: Group 1,5 (Filtek P60), group 2, 3, 4 and group 6, 7, 8 (AeliteFlo, TetricFlow, Revolution/ Filtek P60). All specimens were thermocycled 500 times between 5$^{\circ}C$ and 55$^{\circ}C$ with 1 mimute dwell time, immersed 2% methylene blue dye for 24 hours and then rinsed with tab water. The specimens were embedded in clear resin and sectioned longitudinally through the center of restoration with a low speed diamond saw. Dye penetration at gingival margin was viewed at 20 magnification and analyzed on a scale of 0 to 4. Kruscal-Wallis One way analysis and Mann-Whitney Rank sum test were used to analyze the results. The results of this study were as follows. 1. The leakage values seen at the enamel margin were significantly lower than those seen at the dentin margin(P<0.05). 2. On the enamel margin, packable composite resins with flowable liners showed lower leakage than those without flowable liners, but there were no significant differences among the four groups(P>0.05). 3. On the dentin margin, four groups demonstrated moderate to severe leakage, and there were no significant differences in leakage values(P>0.05).

• Korean Educational Research Journal
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• v.37 no.1
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• pp.67-101
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• 2016

The purpose of this study is to explore and propose policy alternatives by examining students' educational experiences at Chungbuk National University (CBNU). Some of the outstanding research findings of the study as follows. Students at CBNU think that they are capable of team-working and utilizing internet while less so with foreign language skill. With regard to academic achievement, students responded that they have seen a relatively low outcome in foreign language competency. In terms of their job placement, CBNU students highly recognize their logical thinking skill, creativity, and activity, whereas lower satisfaction with social service, study abroad, and internship experience. For further development of the survey analysis, this study suggests additional items included to make a sophisticated analysis possible such as scholarship, part-time job, educational outcome. This is expected to allow researchers to tab into the effect of finance of CBNU students. More detailed information on students' characteristics also need to be added; collaborative learning, student faculty interaction, co-work with students from diverse background, etc., which would allow the analysis of the impact of extra-curricula activities.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.5
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• pp.401-414
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• 2018

Planing hull type ships are often equipped with interceptor or trim tab to improve the excessive trim angle which leads to poor resistance and sea keeping performances. The purpose of this study is to design a controller to control the attitude of the ship by controllable stern interceptor and validate the effectiveness of the attitude control by the towing tank test. Embedded controller, servo motor and controllable stern interceptor system were equipped with planing hull type model ship. Prior to designing the control algorithm, a model test was performed to identify the system dynamic model of the planing hull type ship including the stern interceptor. The matrix components of model were optimized by Genetic Algorithm. Using the identified model, PID controller which is a classical controller and sliding mode controller which is a nonlinear robust controller were designed. Gain tuning of the controllers and running simulation was conducted before the towing tank test. Inserting the designed control algorithm into the embedded controller of the model ship, the effectiveness of the active control of the stern interceptor was validated by towing tank test. In still water test with small disturbance, the sliding mode controller showed better performance of canceling the disturbance and the steady-state control performance than the PID controller.

• Journal of Navigation and Port Research
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• v.30 no.5 s.111
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• pp.405-414
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• 2006

The purpose of this study was to find out morbidity rate and pattern of occupational disease and affect of variables related disease of Fishing crew The subjects this study were 624 Fishing crew who took education course in Korea Institute of Maritime and Fisheries Technology. This questionnaire was focused on finding the basic data for prevention of occupational disease and promotion health on the Fishing crew The collected data were analyzed by using descriptive statistics, Chi-square, cross tab by SPSS package. The result of this study are as follow. 1)The morbidity rate within recent 12 months was 70.2%. there were significant differences of occurred disease in age, rank, perceived health status, fatigue symptoms, rest time, workload, overtime duration 2) the more aging(p<0.01), perceived fatigue(p<0.01), workload(p<0.01), overtime(p<0.05) and the less perceived health status(p<0.01), rest time(p<0.01), the higher morbidity rate 3) Considering disease unable to work more than 4 hour, the number of those who had musculoskeletal disease were 20.9%, which revealed the highest rate, digestive disease 14.3%, traumatic disease 13.5%.

• KIPS Transactions on Software and Data Engineering
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• v.1 no.1
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• pp.19-30
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• 2012

The context aware service is the service to provide useful information to the users by recognizing surroundings around people who receive the service via computer based on computing and communication, and by conducting self-decision. But CAS(Context Awareness System) shows the weak point of small-scale context awareness processing capacity due to restricted mobile function under the current mobile environment, memory space, and inference cost increment. In this paper, we propose a mobile cloud context system with using Google App Engine based on PaaS(Platform as a Service) in order to get context service in various mobile devices without any subordination to any specific platform. Inference design method of the proposed system makes use of knowledge-based framework with semantic inference that is presented by SWRL rule and OWL ontology and Jess with rule-based inference engine. As well as, it is intended to shorten the context service reasoning time with mapping the regular reasoning of SWRL to Jess reasoning engine by connecting the values such as Class, Property and Individual which are regular information in the form of SWRL to Jess reasoning engine via JessTab plug-in in order to overcome the demerit of queries reasoning method of SparQL in semantic search which is a previous reasoning method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.19-27
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• 2006

The purpose of this study was to find of morbidity rate and pattern of disease and affect of variables related disease and medical management of seafares' The subjects this study were 1049 seafares' who took education in Korea Institute of Maritime and Fisheries Technology. This questionnaire was focused on finding the basic data for prevention of disease and promotion health for the seafares' The collected data were analyzed by using descriptive statistics, Chi-square, cross tab, linear regression by SPSS 10.1 package. The result of this study are as follow. 1)The morbidity rate within recent 12 months was 69.0%. 2)there were significant differences of occurred disease in age(p<0.05), income(p<0.01), career of ship on board(p<0.01), rank(p<0.01), perceived health status(p<0.01), worry of health(p<0.01), fatigue symptoms(0.01), satisfy of job(p<0.05), rest time(p<0.05) 3) Considering disease unable to work more than 4 hour, the number of those who had oral disease 7.3%> tinea 6.6%> gastric ulcer 6.4, and musculoskeletal disease group were 20.9%, which revealed the highest rate oral disease 13.6%> skin disease> 12.4%, digestive disease> 12.1%. 4) As refer to medical management, The pain above 31days 35.7%, hospitalization and treatment below 7days were each 50.2%, 42.8%, medical service were doctor's office 27.9, which revealed the highest rate.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.29-38
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• 2006

The purpose of this study was to find out morbidity rate and pattern of occupational disease and affect of variables related disease of Fishing sailors' The subjects this study were 624 fisheries sailors' who took education course in Korea Institute of Maritime and Fisheries Technology. This questionnaire was focused on finding the basic data for prevention of occupational disease and promotion health on the fishing sailors' The collected data were analyzed by using descriptive statistics, Chi-square, cross tab by SPSS package. The result of this study are as follow. 1)The morbidity rate within recent 12 months was 70.2%. there were significant differences of occurred disease in age, rank, perceived health status, fatigue symptoms, rest time, workload, overtime duration 2) the more aging(p<0.01), perceived fatigue(p<0.01), workload(p<0.01), overtime(p<0.05) and the less perceived health status(p<0.01), rest time(p<0.01), the higher morbidity rate 3) Considering disease unable to work more tlnn 4 hour, the number of those who had musculoskeletal disease were 20.9%, which revealed the highest rate, digestive disease 14.3%, traumatic disease 13.5%.

• Journal of Society of Preventive Korean Medicine
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• v.5 no.1
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• pp.116-133
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• 2001

Antifibrotic drugs could be delayed or inhibited massive collagen deposition in liver tissue or inhibited collagen synthesis. we investigated antifibrotic effects by several herbs(Schisnadra chinensis, Ganoderma japonicum, Sedum sarmentosum, Alisma canaliculatum, Plantago asiatica) extract with observations of collagen accumulation in liver tissue and collagen synthesis in sera. Rats were used for experimental animal that were devided 3 groups(sham control, BDL/S, BDL/S-ER). Rats were operated for inducing liver fibrosis(cirrhosis) by bile duct obstruction. Several herbs were prepared by water extraction and were applicated p. o. $3ml/day$ during 4 weeks. After observation period, rats were sacrificed and liver tissue and sera were collected. In result, the mortality of rats was 35% in BDL/S group and 20% in BDL/S-ER The color of bile juice in BDL/S-ER was bright yellow and murky yellow in BDL/S group. The significantly lower weight of liver($16.21g{\pm}5.3,\;20.58{\pm}2.4$) and spleen($1.96g{\pm}0.96,\;3.93{\pm}0.21$) were shown in BDL/S-ER than that of BDL/S(p<0.05) group. The value of collagen in liver tissue(25.7%) in BDL/S-ER was observed significantly lower than that of BDL/S group (Tab. 2). AST. ALT, ALP, t-bilirubin, BUN levels were low in BDL/S-ER as compared with those of BDL/S group, but the significance was not proven. The trichrome stained liver tissue in BDL/S-ER group was observed mild bile duct proliferation and fibrosis compared with BDL/S group. In conclusion, natural products inhibited new collagen synthesis and delayed massive collagen deposition in liver tissue, so that they have noticeable antifibrotic effects in experimental liver fibrosis(cirrhosis).

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.299-308
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• 2000

The purpose of this in vitro study was to evaluate the microleakage of 5 curing methods in class V composite restorations which are composed of two-step light curing, pulse-delay cure, low curing-light intensity, moderate curing-light intensity and high curing-light intensity. In this study, class V cavities were prepared on buccal and lingual surfaces of 50 extracted human upper or lower molars on cementum margin. Single Bond adhesive and Z-100 shade A2 were applied for each group following the manufacture's instruction. The experimental teeth were randomly divided into 5 groups of 10 samples (20 surfaces) each. Group 1: two-step light curing; Group 2: pulse-delay cure; Group 3: low curing-light intensity; Group 4: moderate curing-light intensity; Group 5: high curing-light intensity. After 500 thermocycling between $5^{\circ}C$ and $55^{\circ}C$, the 60 teeth were placed in 2% methylene blue dye for 24 hours, then rinsed with tab water. The specimens were embedded in clear resin, then sectioned buccolingually through the center of restoration with a low speed diamond saw. The dye penetration on each of the specimen was then observed with a stereomicroscope at ${\times}20$. The composite resin/tooth interfaces were examined under Scanning Electron Microscopy. The results were statistically analyzed using the Kruskal-Wallis One Way ANOVA and Dunn's Method. The results of this study were as follows. 1. In all groups, the leakage values seen at the enamel margin were significantly lower than those seen at the dentin margin(P<0.05). 2. No group in this study showed significant differences in leakage values at both the enamel and the dentin margins(P<0.05). 3. In all groups, the gaps seen at the enamel margin were significantly lower than those seen at the dentin margin(P<0.05). 4. The gaps in this study showed significant differences and two-step light-curing and low curing-light intensity produced significant less gap than high curing-light intensity(P<0.05).

• Korean Journal of Family Social Work
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• no.55
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• pp.129-156
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• 2017

The study was conducted to identify factors that affect the first childbearing decisions among married working women in South Korea and thereby to gain insight into effective ways to improve relatively low fertility and unfavorable workplace conditions for women of childbearing age. This study used the merged data(1st-5th waves) from Korean Longitudinal Survey of Women and Families (KLoWF), which were measured by the Korean Women's Development Institute. With 1,020 married business women, cross tab and binary logistic regression were conducted to determine which factors were significantly associated with the first childbearing decisions.