• The korean journal of orthodontics
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• v.41 no.2
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• pp.138-146
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• 2011

The purpose of this article is to introduce a new virtual orthodontic treatment (VOT) system, which can be used to construct three-dimensional (3D) virtual models, establish a 3D virtual setup, enable the placement of the virtual brackets at the predetermined position, and fabricate the transfer jig with a customized bracket base for indirect bonding (IDB) using the stereolithographic technique. A 26-year-old woman presented with anterior openbite, crowding in the upper and lower arches, and narrow and tapered upper arch, despite having an acceptable profile and balanced facial proportion. The treatment plan was rapid palatal expansion (RPE) without extraction. After 10 days of RPE, sufficient space was obtained for decrowding. After a 10-week retention period, accurate pretreatment plaster models were obtained using silicone rubber impression. IDB was performed according to the protocol of the VOT system. Crowding of the upper and lower arches was effectively resolved, and anterior openbite was corrected to normal overbite. Superimposition of the 3D virtual setup models (3D-VSM) and post-treatment 3D virtual models showed that the latter deviated only slightly from the former. Thus, the use of the VOT system helped obtain an acceptable outcome in this case of mild crowding treated without extraction. More cases should be treated using this system, and the pre- and post-treatment virtual models should be compared to obtain feedback regarding the procedure; this will support doctors and dental laboratory technicians during the learning curve.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.965-972
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• 2014

Attitudes and behavior within the store congestion of the store is a store in any manner affect the formation process of investigating synchronism in the control of the consumer appears to analyze the influence of enemy has its purpose. Store and spatial congestion factor of social behavioral factors also revisit the help of word-of-mouth is. Consumer groups with high and low groups of synchronism suggested. Social attitudes towards the store congestion significantly positive effect that I've shown, it was not significant spatial congestion. During a revisit of action is a statistically significant relationship that I've shown, is a significant effect of word-of-mouth relationship was not significant. Investigating the moderating effects of consumer synchronism result of high consumer groups a significant impact on the social congestion showed, at low spatial influence congestion.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.5
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• pp.1-18
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• 2019

A short-turn bus is a bus that is operated within a subsection of an existing bus line. Previous studies regarding short-turn buses decided optimal turn-back points for a single bus line rather than a bus network. Also, in-vehicle crowding which has a significant impact on transit convenience was rarely considered. Therefore, this study aimed to develop a methodology to set priorities for the introduction of short-turn buses of bus lines and sections, considering crowding. To achieve this objective, we calculated occupancies and crowding alleviation benefits of existing bus lines overlapping a new short-turn route based on transit card data, before and after the introduction of short-turn strategy. Also, operator and social costs caused by the introduction of short-turn buses were calculated. Those procedures were iterated over bus lines and sections to operate a short-turn service, and a section whose benefit-to-cost ratio (B/C) is the largest in a line was selected to operate a short-turn service in the line. After, priorities of bus lines to introduce short-turn services could be determined based on B/C values, and the optimum total fleet size could be determined when a short-turn strategy is applied in multiple lines.

• Clean Technology
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• v.17 no.2
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• pp.181-188
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• 2011

In this study, the complementary or crowding-out effects of public R&D subsidy on private R&D investment in the cleaner production were analysed between the effects and the major determinants (company size, R&D investment intensity, ratio of government investment, R&D manpower intensity). Among 207 firms' projects, the number of the complementary effect was 95 (45.9%) while that of crowding-out effect was 38 (18.4%). Resulting from logistic regression, the higher the R&D investment of sponsored companies is, the more complementary effect they show, responding to public R&D subsidy, and increase own R&D investment. The other determinants, however, showed no significant effects on firms' R&D investment. To heighten the effect of public cleaner production R&D, it is need to increase the priority of R&D investment intensity among the determinants. And to increase the performance of governmental R&D investment, further studies for the individual public R&D programs are necessary.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.421-429
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• 2001

Since Non-Extraction treatment in some orthodontic case shows unstable result and unfavorable profile, extraction is selected as inevitable treatment option for the harmonious profile, facial skeleton, and the stable dentition on both arches. For the achievement of proper goal, premolars, molars, sometimes incisors or canines are selected to be extracted. The first Premolar is usually extracted for relieving the crowded dentition with which the molar relations are class I to gain stable dentition and proper profile, but often results in the depression of profile or the loss of vortical dimension. On the contrary, the extracton of the second molar helps maintaining the fullness of profile and the vertical dimension, prevents additional space closural procedures which often make the procedures complicated, relieves both anterior and posterior crowding, and substitutes the extraction fossae for newly erupting 3rd molars. From the point of recurrence, the second molar extraction procedure, therefore, is more beneficial. This cases showed the good results of second molar extraction procedures in the patients with class I crowding.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.3 no.1
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• pp.17-22
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• 2000

Purpose: This study was conducted to evaluate the association between H. pylori infection and socioeconomic status and to determine the current prevalence of H. pylori infection in Korean adolescents. Methods: A structured questionnaire was sent to the children's parents to obtain demographic information on the parents and environmental information. Of the 532 questionnaires sent out, 375 (70.5%; 170 girls and 205 boys) were returned. Their ages ranged from 10 to 15 years (mean, 12.9 years). After collecting blood samples, we measured serum IgG antibody to H. pylori using ELISA method. The association of risk factors such as age, sex, socioeconomic class, type of house, and crowding index with H. pylori infection were analyzed by multiple regression analysis. Socioeconomic status was estimated from the parents' education and occupation using a modified Hollingshead index. Results: The prevalence rate of H. pylori infection was 16.8% (63/375). It increased with age (10.3% at 10~11 years, 15.9% at 12~13 years, and 20.7% at 14~15 years). The H. pylori infection was inversely related to the socioeconomic class (6.3% for the upper class, 16.0% for the middle class, and 20.0% for the lower calss). Crowding condition and type of house did not affect significantly on seroprevalence of H. pylori infection. After logistic regression, we found that the odds ratio for age was 2.2 (95% confidence interval 0.9~5.4), and for socioeconomic status, 3.6 (95% confidence interval 0.5~28.9). Conclusion: The prevalence of H. pylori infection in Korean adolescents was 16.8%. It related inversely to socioeconomic status but was not statistically significant. Socioeconomic status based on parents' education and occupation seemed to affect more on H. pylori seroprevalence than crowding or type of house did.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.507-512
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• 1999

In the mixed dentition, many children have mild crowding of anterior dentition on the mandibular arch and mesial tilting of mandibular molar. Lip bumper have been used to gain arch length for the alignment of mild to moderate crowded dental arches. As such, they may provide an alternative to extraction therapy. The claimed therapeutic effect of the lip bumper is bodily forward incisor movement, flaring of the lower incisors, and distal tipping of the molar. The dental changes can be attributed to removal of lip pressure on the lower anterior dentition and the distal forces exerted at the molar abutment. The purpose of this study is to show more easily method of treatment for mild anterior crowding of mandible.

• The korean journal of orthodontics
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• v.49 no.2
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• pp.116-123
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• 2019

As an alternative to the conventional fixed appliance that uses orthodontic brackets, a simple round tube without a bonding base can be bonded to the tooth surface by covering the tube with flowable resin. In this technique, bent wires cannot be inserted into the simple tubes; therefore, repositioning of the simple tubes is often required for adjustments. To reduce repositioning of simple tubes, a dome-shaped resin covering of the simple tube can be designed with a customized in-and-out compensation, using three-dimensional computer-aided design software based on digital simulation of orthodontic tooth movement. In the present case, the use of simple tubes bonded with customized resin coverings in a Class I nonextraction case is described in a 17-year-old male, in whom moderate crowding of the anterior teeth was treated over an 8-month period. This case shows that simple tubes can be used as an alternative to brackets in some Class I nonextraction cases, with the potential benefit of reducing decalcification.

• Culinary science and hospitality research
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• v.12 no.2 s.29
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• pp.1-17
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• 2006

This study is to develop a viable measurement tool of crowdedness in restaurants. First, to measure customer’s awareness of crowdedness related to each different environmental factor in a restaurant, 49 factors of crowdedness awareness were selected based on the previous studies and then properties of each factor affecting customer’s satisfaction for crowdedness were analyzed. To analyze effects of each factor upon the satisfaction rate, a Multiple Regression Analysis was conducted with the crowdedness awareness as an independent variable and satisfaction of crowdedness as a dependent variable. The results showed that when an analysis of the environmental factors in the crowdedness awareness was conducted in an effort to develop a measurement tool of crowdedness awareness in restaurants, that would be fit for the domestic food service market, based upon 49 factors of restaurant environment. Focusing on expectation and satisfaction rate, it was found that rating the satisfaction level would be a much more effective tool to measure crowdedness awareness because satisfaction rate appeared to be more closely related to the awareness than the results obtained from the Multiple Regression Analysis with a difference between expectation and satisfaction scores as an independent variable.

• Imaging Science in Dentistry
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• v.52 no.4
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• pp.429-434
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• 2022

Supernumerary teeth that are present in the molar region may be evident based on crowding and impaction, but most cases are asymptomatic and discovered as incidental findings during routine radiological examinations. This article reports the case of a 29-year-old woman who presented with a severe feeling of pressure in the region of the maxillary third molars that had been increasing in intensity for weeks. A clinical examination revealed crowding of the maxillary anterior teeth despite the completion of orthodontic treatment and an erupted third molar with localized gingivitis in the second quadrant. A radiographic examination revealed bilateral supernumerary maxillary fourth and fifth molars, so cone-beam computed tomography was performed to locate the supernumerary teeth precisely for a preoperative diagnosis and comprehensive treatment planning. This report presents the radiological and surgical case management of a rare case of bilateral supernumerary molars and reviews the literature regarding epidemiology and treatment options.