• The Journal of Korean Academy of Prosthodontics
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• v.42 no.1
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• pp.83-93
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• 2004

Statement of problem : Since the concept of osseointegrated dental implant by $Br{\aa}nemark$ et al was first applied to mandibular full edentulous patients. Recently it is considerated the first treatment option on missing teeth. A common problem associated with dental implant restorations is loosening of screws that retain the prosthesis to the abutment and the abutment to the implant fixture. Purpose : This study is to examine the influence on screw loosening of implant-abutment designs. Material and methods : External hex, cone screw, beveled hex, cam cylinder, cylinder hex by means of evaluating the loosening torques, with respect to a range of tightening torques after repeated loading. Result : 1. Cone screw, beveled hex groups are the highest initial tightening rate and cylinder hex, external hex groups are the lowest initial tightening rate (p < 0.05). 2. Cone screw groups are the highest after repeated loading tightening rate and cylinder hex groups are lowest after repeated loading tightening rate(p < 0.05). 3. Cone screw groups have the highest initial stability and anal stability. 4. All groups are decreased tightening rate after repeated loading.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.27-28
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• 2023

Currently, the Off-Site Construction (OSC) construction method, which emphasizes the minimization of field work, is being emphasized at construction sites due to the lack of construction skilled manpower, extreme weather, and the Severe Disaster Punishment Act. In this study, we developed a stacked PC modular, which is a method of stacking PC modules, and solved the lifting problem by reducing the weight of the unit module, which is emerging as the biggest disadvantage of PC modules, to around 20 tons. For the connection between modules, structural safety was secured through repeated history tests of the wall and slab connection. Walls and slabs satisfied all statutory fire resistance times through fire resistance tests, and residential performance was evaluated to be satisfactory through mock-up demonstration. The developed PC modular has been applied to the construction of commercial houses, detached houses, shopping malls, churches, etc., and has design results for many buildings such as dormitories, detached houses with 4 floors or more, and resorts, so it is expected that an atmosphere of revitalization of construction methods will be created.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.3
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• pp.116-123
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• 2014

Purpose: The purpose of this study was to evaluate risks for wound dehiscence after guided bone regeneration (GBR) in dental implant surgery. Methods: Patients who received dental implant therapy with GBR procedure at Seoul National University Bundang Hospital (Seongnam, Korea) from June 2004 to May 2007 were included. The clinical outcome of interest was complications related to dental implant surgery. The factors influencing wound dehiscence, classified into patient-related factors, surgery-related factors and material-related factors, were evaluated. Results: One hundred and fifteen cases (202 implants) were included in this study. Wound dehiscence (19.1%) was considered a major complication. The risk of wound dehiscence was higher in males than in females (odds ratio=4.279, P =0.014). In the main graft, the allogenic group had the lowest risk of wound dehiscence (odds ratio=0.106, P =0.006). Though the external connection group had a higher risk of wound dehiscence than the internal connection group (odds ratio=2.381), the difference was not significant (P =0.100). Conclusion: In this study, male gender and main graft have the highest risk of wound dehiscence. To reduce wound dehiscence after GBR, instructions on postoperative care with supplementary procedure for the protection of the wound dehiscence is recommended, especially to male patients. A main graft with a gel base can reduce the risk of wound dehiscence.

• The Journal of Korean Society for School & Community Health Education
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• v.19 no.3
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• pp.95-108
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• 2018

Objectives: The purpose of this study was to investigate the actual conditions and operational problems of Health Promotion Model School' in high school. Methods: We conducted a content analysis of 2014 results report and staffs' responses of five high schools among 85 'Health Promotion Model Schools' led by Ministry of Education from 2012 to 2014. Results: The study examined the operational process of health promoting schools in five stages; system development, needs survey & current status survey, school health policy development, program development & execution, and evaluation. Every step was found to be inadequate. In addition, the study discovered three key factors in operating health promoting schools and examined the status of each factor; connection with the curriculum, connection with the community, and consensus among members. Three factors were also applied poorly. Compared to elementary school, high school showed a lack of all respects. Health promoting school staffs have faced difficulties in linking community resources, organizing and operating a working committee, conducting surveys and assessing health problems, preparing self-assessment or external evaluation, and developing strategies and programs. In order to solve the operational problems, active cooperation of all teachers is urgent. Conclusion: 'Health Promotion Model School' conducted in high school is not considered to have faithfully implemented WHO's concept of health promoting school. In the future, incentive policies for health promoting school teachers should be actively reviewed.

• Journal of the Korean housing association
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• v.23 no.5
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• pp.61-73
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• 2012

This study applied the value of floor-area-ratio standard calculation method to case areas and analyzed them to overcome the limits of previous studies in calculation methods for area standards and land price (value) standard development rights. The results are presented as follows: First, criteria to select sending areas and receiving areas are needed. Second, calculation methods based on the value of floor-area-ratio standard can be widely used as standardized criteria in various areas. Third, for the connection of sending areas with receiving areas, the connections of 1:1, n:1, 1:n, and n:n are available and the location of possible dealing areas should be considered. Also, the choice of connecting unions that meet the purpose of TDR presented by local governments is available. Fourth, for Gwangju, as receiving areas downtown provide higher profits than previous renewal projects, the application of TDR is available. Application methods to overcome problems are presented as follows: First, criteria to select sending and receiving areas should be prepared and implemented in an order of priority. Second, in calculating development rights, methods based on the value of floor-area-ratio standard should be used. Third, the standards and principles of sending and receiving areas should be designated and possible dealing areas should not be limited.

• Journal of Periodontal and Implant Science
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• v.40 no.3
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• pp.139-143
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• 2010

Purpose: Pink gingival esthetic especially on the anterior teeth has been an important success criterion in implant-supported restoration. Inter-implant papillae are a critical factor for implant esthetics, and various techniques for inter-implant papilla reconstruction have been introduced. The aim of this study is to suggest and evaluate a surgical technique for reconstructing inter-implant papillae. Methods: A 28-year-old man had an implant placed on the #13 and #14 area. Four months after implant placement, a second stage surgery was planned for inter-implant papilla reconstruction. At the time of the abutment connection, I-type incisions were performed on the #13i & #14i area followed by full-thickness flap elevation and connection of a healing abutment on underlying fixtures without suture. Results: Two weeks after the second stage implant surgery, soft tissue augmentation between the two implants was achieved. Conclusions: I-shaped incisions for papilla reconstruction performed during the second stage implant surgery were useful for inter-implant papilla reconstruction and showed a good esthetic result.

• Structural Engineering and Mechanics
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• v.47 no.5
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• pp.679-700
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• 2013

Two new predictive design methods are presented in this study. The first is a hybrid method, called neuro-fuzzy, based on neural networks with fuzzy learning. A total of 280 experimental datasets obtained from the literature concerning concentric punching shear tests of reinforced concrete slab-column connections without shear reinforcement were used to test the model (194 for experimentation and 86 for validation) and were endorsed by statistical validation criteria. The punching shear strength predicted by the neuro-fuzzy model was compared with those predicted by current models of punching shear, widely used in the design practice, such as ACI 318-08, SIA262 and CBA93. The neuro-fuzzy model showed high predictive accuracy of resistance to punching according to all of the relevant codes. A second, more user-friendly design method is presented based on a predictive linear regression model that supports all the geometric and material parameters involved in predicting punching shear. Despite its simplicity, this formulation showed accuracy equivalent to that of the neuro-fuzzy model.

• Progress in Superconductivity
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• v.4 no.2
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• pp.172-175
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• 2003

Critical current ratio and n-value of Bi(2223)/Ag superconducting joint tape were measured as a function of uniaxial pressure. In the superconducting joint method, MM and MSM joint were used ; MM joint is direct connection of two -multi filamentary tapes, and MSM is connection of them by using a single -filamentary tape. It was observed that the critical current ratio(CCR) for jointed tapes was not dependent on the uniaxial pressure but joining methods. The n-value of jointed tapes has similar trends with that of the CCR. Especially, double MSM joint showed the highest electrical properties as 63.4-76.0%(CCR) and 3.5-5.1 (n-value). It is considered that the improvements are due to the better inter connections of multifilaments by two single filamentary tapes on both sides.

• International Journal of High-Rise Buildings
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• v.3 no.3
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• pp.231-241
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• 2014

Ductile fracture is one of the most common failure modes of steel beam-to-column connections in moment resisting frames. Most proposed evaluation methods of the plastic deformation capacity of a beam until ductile fracture are based on steel beam tests, where the material's yield strength/ratio, the beam's moment gradient, and loading history are the most important parameters. It is impossible and unpractical to cover all these parameters in real tests. Therefore, a new attempt to evaluate a beam's plastic deformation capacity through analysis is introduced in this paper. Another important issue is about the loading histories. Recent years, the effect on the structural component under long-duration ground motion has drawn great attentions. Steel beams tends to experience a large number of loading cycles with small amplitudes during long-duration earthquakes. However, current research often focuses on the beam's behavior under standard incremental loading protocols recommended by respective countries. In this paper, the plastic deformation capacity of steel beams subjected to long duration ground motions was evaluated through analytical methodology.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.2
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• pp.231-241
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• 1994

To overcome the limit of a point-point connection type service which is common to the ISDN bearer services, a new concept of network element, Service Node, which can provide multiparty connections and control the teleservices on those connections is proposed. This will support conference type multiparty multimedia services among normal ISDN subscribers. In this paper, as a primary study on this concept, we deduce some attributes of the general conference type services and examine the methods and procedures to provide that kind of services through the ISDN. Based on this study, we also define the general requirements and basic structure for the Service Node realization, thus give shape to the concept of it.