• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.2
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• pp.1-12
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• 1989

This paper presents a method of minimizing the wave resistance components, due to the linear wave propagating to the far field and the breaking wave in the vicinity of the hull. This method consists of the linear optimization method for the linear wave resistance and the statistical optimization method for the breaking wave resistance through the analysis of the experimental data. For the purpose of the application, a wall-sided model with parabolic waterplane shape was selected as a basic hull form, and two modified hull forms with varied $C_p-curve$ of the fore-body were derived from the linear wave optimization method and the empirical method. The correlation between the linear wave resistance and the breaking wave resistance according to the $C_p-curve$ variation of the fore-body was investigated through the experimental and analytical results for the three hull forms. The fore-body shape optimized by the present method shows the reduction of the wave resistance by 47% comparing to the basic hull form at the design speed($F_n=0.26$).

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.5.1-5.5
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• 2016

Background: This study clinically evaluated the effect of botulinum toxin type A (BTX-A) in the temporomandibular disorder (TMD) treatment using Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Methods: A total of 21 TMD patients were recruited to be treated with BTX-A injections on the bilateral masseter and temporalis muscles and were followed up by an oral and maxillofacial surgeon highly experienced in the TMD treatment. For each patient, diagnostic data gathering were conducted according to the RDC/TMD. Characteristic pain intensity, disability points, chronic pain grade, depression index, and grade of nonspecific physical symptoms were evaluated. Wilcoxon signed-rank test was applied for statistical analysis. Results: The results showed that more than half of the participants (85.7 %) had parafunctional oral habits such as bruxism or clenching. In comparison between pre- and post-treatment results, graded pain score, characteristic pain intensity, disability points, chronic pain grade, and grade of nonspecific physical symptoms showed statistically significant differences after the BTX-A injection therapy (p < 0.05). Most patients experienced collective decrease in clinical manifestations of TMD including pain relief and improved masticatory functions after the treatment. Conclusions: Within the limitation of our study, BTX-A injections in masticatory musculatures of TMD patients could be considered as a useful option for controlling complex TMD and helping its associated symptoms.

• The korean journal of orthodontics
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• v.22 no.2 s.37
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• pp.449-474
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• 1992

The purpose of this study was to evaluate the in vitro shear bond strengths to enamel and the failure sites of three ceramic brackets and one metal bracket in combination with light cured orthodontic adhesive. The brackets were divided into four groups. Each ceramic bracket group had different bonding mechanisms with adhesive. Group A; metal bracket with foil-mesh base (control group) Group B; ceramic bracket with micromechanical retention Group C; ceramic bracket with chemical bonding Group D; ceramic bracket with mechanical retention and chemical bonding. Forty extracted human lower first premolars were prepared for bonding and 10 brackets for each group were bonded to prepared enamel surfaces with $Transbond^{\circledR}$ light cured ortho dontic adhesive. Twenty four hours after bonding, the Instron universal testing machine was used to test the shear bond strength of brackets to enamel. After debonding, brackets and enamel surfaces were examined under stereoscopic microscope to determine the failure sites, Statistical analysis of the data was carried out with ANOVA test and $Scheff\acute{e}$ test using SPSS PC+. The results were as follows. 1 . There were statistically significant differences in mean shear bond strengths of three ceramic bracket groups (p < 0.05). Shear bond strengths of group C and D were significantly higher than that of group B and shear bond strength of group C was significantly higher than that of group D. 2. Group C and D both had significantly higher shear bond strengths than metal bracket (group A), but there were no significant differences in shear bond strengths between group A and B (p < 0.05). 3. The failure sites of four bracket groups were also different. Group C and D failed primarily at enamel-adhesive interface, but group A and B failed primarily at bracket base-adhesive interface. 4. Among all ceramic bracket groups, group B was very similar to metal bracket in the aspect of shear bond strength and failure site.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.204-212
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• 2003

As the first step to investigate the nonlinear interactions between turbulence and marine structures inside a viscous NWT, a LES technique was applied to the turbulent channel flow for $Re_{T}=150$, in this paper. The employed models were 4 types, such as the Smagorinsky model, the Dynamic SGS model, the Structure Function model and the Generalized Normal Stress model. The simulated data in time-series for the LESs were averaged in both time and space and performed statistical analysis. And results of the LESs were compared with those of a DNS developed in the present study and two spectral methods by Yoon et al.(2003) & Kim et al.(1987). It seems to be quite difficult to evaluate their performances to the present problem, but is seen that the accuracy of LESs are still related to the number of grids(or fine grid size).

• Journal of the Korean Home Economics Association
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• v.46 no.2
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• pp.51-58
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• 2008

The purpose of this study was to analyze how the appreciation or recognition of quick response systems, with the utilization of technology, can improve operations for businesses in the DongDaeMoon fashion market. A survey was conducted from April 25 to May 10 in 2007, among owners and designers of wholesale shops in the DongDaeMoon fashion market. Data was collected from 270 subjects, and general descriptive and comparative statistical analysis was applied to acquire various parameters. Firstly, the product types within the DongDaeMoon fashion market were small and medium quantity batch production systems. The majority of businesses adopted the production strategy of outsourcing through subcontracted factories. To re-order, a fashion merchandising required 2 to 3 days. Secondly, the design sources of fashion merchandises were national fashion brands, popular items within the same industries, and also fashion magazines. New products was made within 4 days after a sample item was received. Business acquaintances were fashion retail shops of DongDaeMoon, and internet or home shopping companies. Thirdly, the recognition of importance and effects of quick response systems was difference between high and low group of the utilization of technology in the DongDaeMoon fashion market.

• Journal of Korea Game Society
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• v.15 no.1
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• pp.145-154
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• 2015

The objective of this research is to evaluate the usability test of 'Paldokangsan3' which has been developed as a serious game for the elderly to improve their physical and mental health. This game machine has been installed in a silver house for one month that the elderly could play the game as they like in their convenient times. To promote their participations to practice the game, we set 3 contests with gifts for the high scores and collect their data through inspection, questionnaire and interviews by the researchers as well as in-game measurement for the play. Eight people volunteered to join the project. While the result analysis for the usability area of easiness of control, learnability of the game play, memorability and challenge didn't show the statistical confident t-value, most elderly players participated 2~3 times a day for a month even though most of them are suffering mild cognition impairment. They showed good subjective satisfactions in their interviews that we could go on the project further to expand its applications.

• The korean journal of orthodontics
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• v.50 no.6
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• pp.383-390
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• 2020

Objective: To investigate the distribution, side involvement, phenotype, and associated anomalies of Korean patients with craniofacial clefts (CFC). Methods: The samples consisted of 38 CFC patients, who were treated at Seoul National University Dental Hospital during 1998-2018. The Tessier cleft type, sex, side involvement, phenotype, and associated anomalies were investigated using non-parametric statistical analysis. Results: The three most common types were #7 cleft, followed by #0 cleft and #14 cleft. There was no difference between the frequency of male and female. Patients with #0 cleft exhibited nasal deformity, bony defect, and missing teeth in the premaxilla, midline cleft lip, and eye problems. A patient with #3 cleft (unilateral type) exhibited bilateral cleft lip and alveolus. All patients with #4 cleft were the bilateral type, including a combination of #3 and #4 clefts, and had multiple missing teeth. A patient with #5 cleft (unilateral type) had a posterior openbite. In patients with #7 cleft, the unilateral type was more prevalent than the bilateral type (87.0% vs. 13.0%, p < 0.001). Sixteen patients showed hemifacial microsomia (HFM), Goldenhar syndrome, and unilateral cleft lip and palate (UCLP). There was a significant match in the side involvement of #7 cleft and HFM (87.5%, p < 0.01). Patients with #14 cleft had plagiocephaly, UCLP, or hyperterorbitism. A patient with #30 cleft exhibited tongue tie and missing tooth. Conclusions: Due to the diverse associated craniofacial anomalies in patients with CFC, a multidisciplinary approach involving a well-experienced cooperative team is mandatory for these patients.

• The Journal of Advanced Prosthodontics
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• v.8 no.3
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• pp.224-228
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• 2016

PURPOSE. This study aimed to investigate whether dentin surface preparation with diamond rotary instruments of different grit sizes affects the shear bond strength of resin-bonded restorations. MATERIALS AND METHODS. The buccal enamel of 60 maxillary central incisors was removed with a low speed diamond saw and wet ground with silicon carbide papers. The polished surfaces of the teeth were prepared with four groups of rotary diamond burs with super-coarse (SC), coarse (C), medium (M), and fine (F) grit sizes. Following surface preparation, 60 restorations were casted with nickel-chromium alloy and bonded with Panavia cement. To assess the shear bond strength, the samples were mounted on a universal testing machine and an axial load was applied along the cement-restoration interface at the crosshead speed of 0.5 mm/min. The acquired data was analyzed with one way ANOVA and Tukey post hoc test (${\alpha}=.05$). RESULTS. The $mean{\pm}SD$ shear bond strengths (in MPa) of the study groups were $17.75{\pm}1.41$ for SC, $13.82{\pm}1.13$ for C, $10.40{\pm}1.45$ for M, and $7.13{\pm}1.18$ for F. Statistical analysis revealed the significant difference among the study groups such that the value for group SC was significantly higher than that for group F (P<.001). CONCLUSION. Dentin surface roughness created by diamond burs of different grit sizes considerably influences the shear bond strength of resin bonded restorations.

• Korean Journal of Occupational Health Nursing
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• v.7 no.1
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• pp.97-114
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• 1998

The occupational health services for the minor enterprises are poor comparing with that of large enterprises in Korea. In 1997, Korean government announced officially the law on joint employment system of occupational health practitioners to solve the problems. This study is to develop the model on the joint employment system of occupational nurse practitioners for minor enterprises in Korea based on the opinions of occupational health nurses (OH Ns). The data were collected by questionnares from October to November in 1997. The number of subjects was 210 occupational health nurses who had participated the mandatory nursing education program provided by the Korean Occupational Health Nurses Association(KOHNA). The response rate was 47.1%. The contents of questionnaires were general characteristics, occupational & job characteristics of OHNs, and the views on the joint employment system. The SAS-PC program was used for the statistical analysis. The results were as followed, (1) The proper number of industies was 3 and the appropriate number of workers was 448 for one joint employed occupational nurse practitioner (J EONP). (2) 44.7% of the OHNs wanted that the Ministry of Labor monitored the way and content of contraction b/w JEONP and minor emterprises, 82.6% of the OHNs wanted that KOHNA managed the employment informations. (3) The OHNs of occupational health agencies showed more positive attitude than the OHNs of private industries on the joint employment system. (4) 88.3% of the OHNs wanted the education training for JEONP. Especially in occupational hygiene and safety control. (5) The OHNs expected the role expansion of Occupational Health Nursing by JEONP system. At the same time they worried the adverse effects. For the successful execution of this system, it is necessary the cooperation among the Ministry of Labor, KOHNA, the minor enterprises, and the OHNs.

• Korean Journal of Social Welfare
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• v.55
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• pp.181-204
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• 2003

The purpose of this study was to offer a comprehensive analysis of the changing trends of the Korean income packaging, poverty rate, and level of income inequality from 1996 to 2002. In order to do that, this study used the micro-data of "Income and Expenditure Survey of Urban Households" by the National Statistical Office(NSO). Major results were as follows: (1) A ratio of public transfer in family income packaging increased at the DJ administration. (2) Poverty rate and Gini coefficient, which were 7.8% and 0.29 in 1996, rose to $8.8{\sim}10.4%$ and $0.30{\sim}0.34$ respectively during the year of 1998-2002. (3) However, poverty reduction effect and income inequality reduction effect of public income transfer increased preferably at the DJ administration. Those effects increased more since the enactment of National Basic Livelihood Security in 2000. Therefore, government should provide more national welfare programs to reduce the poverty rate and to improve better structure of income distribution.