• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.44-50
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• 2021

This study analyzed the stability of antenna equipped on vehicles by the link of modal analysis and random vibration analysis with the vibration data of MIL-STD-810H, METHOD 514.8. As a result of the random vibration analysis of antenna, the maximum equivalent stress 41.9MPa and minimum margin of safety 8.37 was generated in the bracket of antenna by the vertical direction vibration. Thus, it was found that antenna has enough stability during the operation.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.12 s.189
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• pp.88-94
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• 2006

In this study, the dynamic impact analysis for the passenger air-bag(PAB) module has been carried out by using FEM to predict the dynamic characteristics of vehicle ride safety against head impact. The impact performance of vehicle air-bag is directly related to the design parameters of passenger air-bag module assembly, such as the tie bar bracket's width and thickness, respectively, However, the product's design of PAB module parameters are estimated through experimental trial and error according to the designer's experience, generally. Therefore, the dynamic analysis of head impact test of the passenger air-bag module assembly of automobile is needed to construct the analytical methodology At first, the FE models, which are consist of instrument panel, PAB Module, and head part, are combined to the whole module system. Then, impact analysis is carried out by the explicit solution procedure with assembled FE model. And the dynamic characteristics of the head impact are observed to prove the effectiveness of the proposed method by comparing with the experimental results. The better optimized impact performance characteristics is proposed by changing the tie bracket's width md thickness of module. The proposed approach of impact analysis will provides an efficient vehicle to improve the design quality and reduce the design period and cost. The results reported herein will provide a better understanding of the vehicle dynamic characteristics against head impact.

• The korean journal of orthodontics
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• v.43 no.5
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• pp.242-247
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• 2013

Objective: To test the null hypothesis that no difference exists between the effects of at-home bleaching and in-office bleaching on shear bond strength (SBS) with bracket bonding at 4 different time intervals after dental bleaching. Methods: Ninety extracted human premolars were randomly divided into 9 groups (n = 10) according to the bleaching methods used (at-home bleaching and in-office bleaching) and the storage time in artificial saliva (30 min, 1 day, 2 weeks, and 3 weeks before bonding). The control group was stored in artificial saliva for 7 days. Brackets were bonded with the Transbond XT adhesive system, and SBS testing was performed. The adhesive remnant index (ARI) was used to assess the amount of resin remaining on the enamel surfaces after debonding. The SBS data were analyzed by analysis of variance (ANOVA) and the Tukey test. For the ARI, the Kruskal-Wallis test was performed. Significance for all statistical tests was predetermined to be p < 0.05. Results: The SBS of the unbleached group was significantly higher (p < 0.05) than that of the bleached groups (except for the group bonded 30 min after at-home bleaching). Conclusions: The null hypothesis was not totally rejected. All bleaching groups tested had decreased SBS of the brackets to the enamel, except for the group bonded 30 min after at-home bleaching. The SBS returned to values close to those of the unbleached enamel within 3 weeks following bleaching.

• Journal of the Korean Home Economics Association
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• v.18 no.1
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• pp.53-66
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• 1980

One of the most pressing problems of the day in our household economy is the scientific improvement of meal management, which has direct bearings on the efficiency of housewives, domestic economy, and health care for the whole family. The concern of this paper is to investigate the current meal management situation in which more than three hundred housewives in Seoul find themselves, and to propose a tentative plan for its improvement. The result of the investigation is summarized as follows : 1) The number of families with old-fashioned kitchens forms a percentage of 30.3 ; only 4.3 percent of them have waterworks and drainage system. 2) The number of families equipped with cooking machines and utensils constitutes 51.2 percent ; that of those without cooking machines reaches the high percentage of 92.8. 3) The expense for daily meals amounts to 37.9 percent of the whole domestic expenses. the number of those who prepare daily meals without any planning comprises 78 percent. It is from habit that 60.5 percent of them make no workable plan for their meals. 4) The frequency of housewives doing daily marketing is comparatively high. 5) The time spent in preparing and clearing the table is 280.4 minutes a day on the average. 6) In preparing daily meals the low income bracket tends to keep expense as low as possible, while the high income bracket is chiefly concerned with taste. 7) The frequency of home cooking is on the increase as the housewives grow older, especially in the large families with housemaids. 8) In most cases housewives do the cooking for themselves; the high income brackets have housemaids do the cooking. The number of husbands who help their wives do kitchen work a small percentage of 10-14. 9) The simplification of kitchen work presupposes the simplification of the daily cooking, the improvement of the structure and equipment of the kitchen, and a good help of the whole family.

• Health Policy and Management
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• v.21 no.4
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• pp.511-526
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• 2011

This study aims at surveying how Koreans look upon and prepare for the age of longevity("age of 100 years") drawing near at hand, analyzing factors affecting such a perception and behavior. To this end, a telephone survey was launched for 1200 persons sampled to evenly comprise the young, middle-aged, and elderly groups. Our findings indicate that more Koreans looked upon the upcoming "age of 100 years" as a 'disaster' rather than a 'blessing.' The sense of combined uneasiness over the aged life being further elongated while they are unprepared for it, anxiety over maintaining health and so forth came into play. However, the better a person is prepared by way of health management, savings for retirement, preparation for leisure activities and employment for the later life, the more positively he or she looked upon the "age of 100 years". An analysis by group indicates that women rather than men, the elderly rather than the young, the less educated rather than the highly educated, the low-income bracket rather than the high-income bracket looked upon the "age of 100 years" more negatively. Under such circumstances, it is suggested that the nation's social system tailored to a life expectancy of 80 years should be readjusted, tailored to a 'longevity paradigm' and that to this end social systems should be reoriented toward the direction where 'healthy aging' and 'active aging' are fully supported.

• The korean journal of orthodontics
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• v.24 no.2
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• pp.479-508
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• 1994

This study was designed to investigate the reciprocal movement which was derived form application of active torque in ideal archwire by computer-aided three-dimensional finite element analysis of maxillary teeth and surrounding periodontal ligament composed of 2617 elements and 3725 nodes. Ideal archwire model was also made using the beam elements and the contact between the wire and the bracket slot was made using the gap element. In this study non-linear elastic behaviors of contact between the wire and the bracket slot were considered on. We put the active torque between the lateral and cenral incisor and between the second premolar and the first molar with/without cinch-back. The results were expressed by quantitative and visible ways. The findings of this study were as follows: 1. Reciprocal actions to active torque were complex system consisting of a combination of counter-torque, bucco-lingual linear displacement and tipping, rotation of the teeth, occluso-gingival linear displacement. 2. When active anterior crown labial torque was applied, crown labial tippings of the lateral were the greatest, and those of the central incisor was the next, Crown lingual tippings of the canine and the first premolar, mesial rotations and extrusion of the lateral and distal rotations and intrusion of the canine occurred. When anterior torque with the cinch-back was applied, amount of crown labial tippings of the lateral and central incisor were reduced. Amount of crown lingual tipping of the canine and the first premolar were increased. Mesial tippings and mesial rotations of the second molar occurred. 3. When active posterior crown lingual torque was applied, crown lingual tippings of the first moalr were the greatest, and crown labial tippings of the second premolar and the first premolar were the next, the crown lingual tipping of the second molar were a little. Mesial rotations of the second premolar occurred but those of the first premolar didn't occurred.

• The korean journal of orthodontics
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• v.44 no.3
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• pp.119-127
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• 2014

Objective: To evaluate the long-term effects of self-ligating brackets (SLBs) on transverse dimensions of arches and skeletal and soft tissues and to quantitatively evaluate the treatment outcome after non-extraction treatment with SLBs. Methods: The sample consisted of 24 (18 female and six male) subjects, with a mean age of $14.23{\pm}2.19$ years, who received treatment with the Damon$^{(R)}$3 appliances. Complete records including cephalometric radiographs and plaster models were obtained before treatment (T1), immediately after treatment (T2), six months after treatment (T3), and two years (T4) after treatment. Digital study models were generated. Twenty lateral cephalometric, six frontal cephalometric, and eight dental cast measurements were examined. The Peer Assessment Rating index was used to measure the treatment outcome. The Wilcoxon test was applied for statistical analysis of the changes. Results: There were significant increases in all transverse dental cast measurements with active treatment. There was some significant relapse in the long term, particularly in maxillary width (p < 0.05). Statistically significant increases were found in nasal (p < 0.001), maxillary base, upper molar, lower intercanine, and antigonial (p < 0.05) widths in T1-T2. Lower incisors were proclined and protruded in T1-T2. Conclusions: SLBs correct crowding by mechanisms involving incisor proclination and protrusion and expansion of the dental arches, without induction of clinically significant changes in hard and soft tissues of the face.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4A
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• pp.307-313
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• 2009

In this study, in order to research the repair-strengthening methods, when fatigue crack occurs in the coped stringers of a steel railway bridge, we manufacture the full size of crossbeam-stringer and floor system model. Also the experimental test is performed on the coped stringers applying the repair-strengthening methods using the stop hole, combination plate, connection plate, bracket, and so on. The results indicate that, the most effective method is to set up connection plate and bracket in the top flange and bottom flange of the stringers, while we can consider the method of punching stop holes in the end of the crack as a subsidiary method. It is necessary to set up the combination plate when the length of crack is quite long.

• Journal of the Korean Society of Costume
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• v.64 no.6
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• pp.33-46
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• 2014

The purpose of this study is to present basic data for the standardization of the sizing system for children's wear by investigating the current production and sizing system of Korean children's wear brands. The result of conducting a survey of 20 brands show the following: first, regarding the age bracket of Korean children's wear, it ranged from 3~15 years old. Most of the brands divided up the sizes into 4 or 5 different groups. Second, the utilization of a bodice basic pattern was low during the manufacturing of a pattern, and the basic pattern had been used for the item. Third, the designation of garment sizes were done using height or height-chest measurement or height-waist measurement. Fourth, the brands used the smallest size as the basic size in most cases. Most of the brands had similar deviations for any grading deviations. In conclusion, it appears necessary to restructure the unity of size designation and the sizing system in order to establish the sizing system of children's wear, which features diverse age brackets and various body types.

• Journal of Families and Better Life
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• v.25 no.5
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• pp.185-197
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• 2007

Permanent rental housing which is entirely financed by the Government is welfare housing for those who fall within the lowest income bracket. This type of housing is intended for use as rental housing on a long-term basis. At present, there are about 190,000 permanent rental housing units in Korea. The purpose of this study is to suggest the implications to improve the management and welfare service system of permanent rental housing. For this, qualitative data were collected by using the in-depth interview with staffs of community welfare center and management office of five permanent rental housing complexes and two times of advisory committee meeting with housing and social welfare experts. To analyze the data gathered in this study, the constant comparative method of data analysis was used. Conflicts between the management office and social welfare center of permanent rental housing could be classified into two aspects; personal and operational. Main reasons for the conflicts between two institutions were identified such as attitude of management office staffs, lack of cooperation, current administrative system, lack of management resources such as space and operation cost, and so on. Based on the results, some implications including institutional support and social complementary cooperation were suggested for improvement of management and welfare service system for the residents of permanent rental housing.