• The Journal of Korean Academy of Prosthodontics
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• v.41 no.2
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• pp.128-135
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• 2003

Statement of problem : Implant screw loosening remains a problem in implant prosthodontics. Some abutment screws with treated surfaces were introduced to prevent screw loosening and to increase preload. DLC(Diamond Like Carbon) film has similar properties on hardness, wear resistance, chemical stability, biocompatibility as real diamond materials. Purpose : The purpose of this study was to investigate the effect of lubricant layer on abutment screw and to discriminate more effective method between soft lubricant and hard lubricant to prevent screw loosening. Material and method : In this study, $1{\mu}m$ thickness DLC was used as protective, lubricating layer of titanium screws and 3 times removal torque was measured on the abutment screws to investigate the difference in 10 coated and 10 non-coated abutment screws. Results : The results indicated that the implants with DLC coating group were not more resistant to the applied force in screw loosening. At 32Ncm, the 3 times removal torque in DLC group were $27.75{\pm}2.89,\;25.85{\pm}2.35$ and $26.2{\pm}2.57$. The removal torque in no-coated abutment screws were $27.85{\pm}4.23,\;27.35{\pm}2.81$ and $27.9{\pm}2.31$, respectively. Conclusion : The lubricant layer used in this study was Diamond Like Carbon(DLC) and it have a properties of hard and stable layer. The DLC coating layer was hard enough to prevent distortion of screws in the repeated unscrewing procedure in clinical situation. The reduced friction coefficient in hard DLC layer was not effective to prevent screw loosening.

• Journal of Periodontal and Implant Science
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• v.37 no.2
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• pp.277-286
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• 2007

The edentulous posterior maxilla generally provides a limited amount of bone height because of atrophy of the ridge and pneumatization of the maxillary sinus, Maxillary sinus augmentation is one of the surgical techniques for reconstruction of the severely resorbed posterior maxilla. The purpose of this study was to evaluate the survival rate of implants and the long-term changes of graft height after maxillary sinus augmentation by lateral window approach. From September 1996 to July 2004, maxillary sinus augmentation with mixed grafts of autograft, allograft, xenograft and alloplast were performed on 45 patients and 100 implants were placed. We evaluated the survival rate of implants and the changes of BL(bone length)/IL(implant length) according to time using panoramic radiographs. The survival rate of implants was 91.0% for follow-up period. The mean reduction of graft heights was 0.34mm(3.0%) for 6 months and 1.22mm(1O.66%) for 3 years after augmentation. The total mean BL/IL was $1.34{\pm}0.21$ during 5 year observation period after augmentation and decreased slightly over time. The result means that graft materials were stable above the implant apex. BL/ILs of 1stage procedure were significantly decreased at 1-2 year, 3-4 year after augmentation and no statistically significant changes were observed in those of 2 stage procedure. The graft materials of both procedures were stable above the implant apex. No statistically significant changes of BL/IL were observed in the grafts combined with low amount of autogenous bone or without autogenous bone. The graft materials of both groups were stable above the implant apex. The results indicated that the placement of dental implants with maxillary sinus augmentation showed predictable clinical results and the grafts combined with low amount of autogenous bone or without autogenous bone had long-term resistance to resorption in maxillary sinus.

• Journal of The Korean Association For Science Education
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• v.30 no.1
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• pp.80-93
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• 2010

The scope of this study is: (1) to review or summarize the theoretical explanations of diffusion; (2) to investigate the preservice teachers' understanding of diffusion utilizing the inquiry experiment of diffusion that was developed in this study. The data was collected through questionnaires given to 41 preservice teachers in 3 universities and interviews with 20 subjects from this population, who conducted the inquiry experiment. During the experiment, the data was collected from the students' reports and 3 small groups' audio/video recordings. To understand preservice teachers' conceptions, reports, audio/video recordings, questionnaires and interviews were analyzed and discussed with co-workers. The results follow: (1) The differences between effusion and diffusion as well as equal-pressure experiment and equal-flux one on diffusion were discussed; (2) Most preservice teachers understood effusion and diffusion connected to Graham's law of diffusion by rote and have misconceptions about the diffusion process; (3) They observed two kinds of diffusion experiments (equal-pressure and equal-flux) by inquiry experiment, but the majority of them failed to find conceptual differences between these experiments. After the inquiry experiment, about 40% of the samples modified their conceptions about diffusion.

• Culinary science and hospitality research
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• v.21 no.1
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• pp.250-266
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• 2015

This study concentrated on the dining out consumption behaviors, dining out selection attributes, and changes in eating habits of silver generation. Total 216 residents in metropolitan area were employed for statistical analysing. The results are as follows. First, as the result of t-test and ANOVA showed that female and higher academic background tended to regularly take high level of fruits, vegetables, meat, and fish eating habits. These results identified that dining out culture and dietary lifestyle are closely linked. Second, as the result of difference in dining out consumption attitudes on eating habit of silver generation, consumers who have better eating behaviors tended to consider the physical environment, variety of menu, and service quality when they choose a restaurant. Third, as the result of analysis on changes in dining out consumption behavior based on eating behavior of silver consumers, groups differences were found from only the source for information on dining out business and standard variable in selection of dining out business. Fourth, physical environment, variety of menu, business quality, and service were indicated as significant selection attributes of dining out among silver peoples. Fifth, dining out consumption behaviors of silver consumers were developed through newspapers, magazines, and previous visiting experiences. In conclusion, the results of present study showed that silver consumers tend to select a restaurant based on word-of-mouth and various factors related to experiences. Hence, various promotional activities are necessary for the business succession.

• Journal of Convergence for Information Technology
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• v.7 no.4
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• pp.97-103
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• 2017

The purpose of this study was to investigate muscle activity of cervical erector spinae & upper trapezius while using a smartphone according to anterior pelvic tilt & posterior pelvic tilt in sitting position. & we also want to obtain basic data necessary for development of IoT devices. Fifteen healthy men & women aged 20-30 were enolled, After anterior pelvic tilt & posterior pelvic tilt in sitting position were adjusted, they used a smartphone for 5 minutes & EMG signal was measured simultaneously. We used median 3 minutes of measured EMG signal. The results of this study were as follows: In the sitting position, the use of smartphone in anterior pelvic tilt had significantly lower %RVC values in both cervical erector spinae (p <.001), left upper trapezius (p <.001) & right upper trapezius (p <.002) in comparison with posterior pelvic tilt. This means that anterior pelvic tilt make vertebrae maintain normal curvature & prevent forward head posture occurred while using a smartphone. It reduces loads around neck & shoulders, so that %RVC value is significantly lowered. In the future, new posture corrected IoT devices with an aspect of pelvic tilt should be developed.

• Journal of Korea Water Resources Association
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• v.39 no.2 s.163
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• pp.109-120
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• 2006

Permeable pavement and release of treated wastewater into streams can increase streamflow of urban streams for a dry weather period. A SWMM code was modified to have a permeable pavement option. The modified SWMM was applied to continuous simulations of urban runoff from Hakuicheon watershed and it was used to analyse the effect of a permeable pavement installation and the reuse of treated wastewater. A critical error in the pan coefficient multiplication was also corrected in the modification. The analysis results of the reuse of treated wastewater is as follows: The low flow ($Q_{275}$) increases by 1.63 times as much as the current one and the drought flow ($Q_{355}$) increases by 3.57 times as much as the current one. If the impervious area in the Hakuicheon watershed is replaced with the permeable pavement area by 10 percent, the low flow and the drought flow increases by 3 percent and 17 percent, respectively. The results shows the effectiveness of the release of treated wastewater into stream to increase urban streamflow. The permeable pavement installation also play a minor role in the drought flow increase.

• Journal of Gifted/Talented Education
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• v.26 no.4
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• pp.677-697
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• 2016

This study analyzed the difference in evaluation results in evaluating identical products by applying two different types of evaluating scales, Creative Product Analysis Matrix (CPAM) and Creative Product Semantic Scale (CPSS) by O'Quin and Bessember (1989). As a result, evaluation based on explicit knowledge scored lower than evaluation based on implicit knowledge, implying that the evaluation becomes stricter. When evaluated with CPSS, which as relatively more segmentalized grading criteria, all sub-dimensions of creativity showed low scores, and it show that when evaluator's first impression or personal evaluation standard on the products is firm, they may not be evaluated by the evaluation tools. Gifted education teachers were giving similar evaluations as experts in creative product evaluation, and understanding the product evaluation tool fully in advance before teaching or evaluating products may lead to the generation of newer, more useful and appropriate, and highly creative product with high solvability.

• KSBB Journal
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• v.19 no.6 s.89
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• pp.433-436
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• 2004

Polycystic ovarian syndrome (PCOS) is a very common endocrine disorder in women of reproductive age. There are some evidences that nerve growth factor (NGF) is involved in the pathogenesis of PCOS. In this study, we investigated the effect of Korean red ginseng total saponin (GTS) on the ovarian morphology and NGF expressions in the ovaries, pituitary and hippocampus. The oil control animals were injected with 0.2 ml oil/rat. Animals in estradiol valerate (EV) control group were injected i.m. with 4 mg EV in 0.2 ml oil/rat. The GTS was administered (100 mg/kg) i.p. every other day for 60 days, beginning 1 day after the EV injection. PCO was induced by a single injection of EV (4 mg, i.m.). At day 60, the expressions of NGF were examined by immunohistochemistry. The main findings were as follows; PCO was fully developed with a single i.m. injection of EV, and PCO showed the increased expression of NGF, and GTS administration decreased NGF expressions in the ovaries without affecting pituitary and hippocampus significantly. The present results demonstrate that GTS attenuates PCOS by the stimulation of NGF expression.

• The Korean Journal of Financial Management
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• v.26 no.2
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• pp.33-61
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• 2009

From the perspective of corporate governance, we examine the acquirers' performance of mergers and acquisitions in KOSDAQ Market. The empirical results of our study show that inside an executive shareholders and outside minor shareholders, affect acquirers' performance in M&A's : the ownership of outside minor shareholders is positively correlated with the performance of acquirers. and, the ownership of insiders, such as that of an executive shareholders, does have significant effect on the performance of M&A's. Since the current literature concludes that the improvement of corporate governance in KOSDAQ Market would enhance the shareholders' wealth, the results of our study implies that outside minor investors, as well as insiders, are playing an important role in the corporate governance.

• KSBB Journal
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• v.27 no.1
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• pp.1-8
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• 2012

Recently, translational research (TR) in health technology (HT) has been considered as an emerging alternative research system for the improvement of human health. TR from bench to bedside involves a strong bidirectional relationship between basic science discovery and clinical practice. To support R&D planning and policy in HT effectively, the performance of TR programs was analyzed and evaluated in a R&D project on health and medical technology. TR programs were classified into three parts: unilateral TR, bilateral TR and multilateral TR. Bibliometrics and citation analysis were performed to assess research papers and gather information for the performance analysis of TR programs. In addition, both quantitative and qualitative analysis were successfully carried out using ISI Web of Science, Google Scholar Citations, SCOPUS and Knowledgematrix. In conclusion, the performance analysis of TR programs could significantly improve the efficiency of R&D plans, R&D management and evaluation for a safe and healthy life.