• Journal of The Korean Association For Science Education
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• v.28 no.5
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• pp.471-481
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• 2008

This study investigated connecting errors by students' field independence-dependence in learning chemistry concepts with multiple external representations in current science textbooks. Seventh graders (N=196) at a middle school were assigned to the BL and CL groups, which were respectively taught "Boyle's Law" and "Charles's Law." A field independence-dependence test was administered. After learning the target concept with text and picture emphasizing the particulate nature of matter, a connecting test was also administered. Five types of connecting errors were identified: Insufficient connection, misconnection, rash connection, impossible connection, and failing to connect. 'Failing to connect,' 'Misconnection,' and 'Rash connection' were found to be the frequent types of connecting errors regardless of the target concepts. The frequencies and percentages of the types of connecting errors were not significantly different between the field independent and field dependent students. Educational implications of these findings are discussed.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.2
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• pp.226-237
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• 2004

Purpose: Four finite element models were constructed in the mandible having a single implant fixture connected to the first premolar-shaped superstructure, in order to evaluate how the shape of the fixture and the implant-abutment connection would influence the stress level of the supporting tissues fixtures, and prosthethic components. Material and methods : The superstructures were constructed using UCLA type abutment, ADA type III gold alloy was used to fabricate a crown and then connected to the fixture with an abutment screw. The models BRA, END , FRI, ITI were constructed from the mandible implanted with Branemark, Endopore, Frialit-2, I.T.I. systems respectively. In each model, 150 N of vertical load was placed on the central pit of an occlusal plane and 150 N of $40^{\circ}$ oblique load was placed on the buccal cusp. The displacement and stress distribution in the supporting tissues and the other components were analysed using a 2-dimensional finite element analysis . The maximum stress in each reference area was compared. Results : 1. Under $40^{\circ}$ oblique loading, the maximum stress was larger in the implant, superstructure and supporting tissue, compared to the stress pattern under vertical loading. 2. In the implant, prosthesis and supporting tissue, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 3. In the superstructure and implant/abutment interface, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 4. In the implant fixture, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 5 The stress was more evenly distributed in the bone/implant interface through the FRI of trapezoidal step design. Especially Under $40^{\circ}$ oblique loading, The maximum stress was smallest in the bone/implant interface. 6. In the implant and superstructure and supporting tissue, the maximum stress occured at the crown loading point through the ITI. Conclusion: The stress distribution of the supporting tissue was affected by shape of a fixture and implant-abutment connection. The magnitude of maximum stress was reduced with the internal connection type (FRI) and the morse taper type (ITI) in the implant, prosthesis and supporting tissue. Trapezoidal step design of FRI showed evenly distributed the stress at the bone/implant interface.

• Journal of Korean Association for Spatial Structures
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• v.23 no.2
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• pp.45-52
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• 2023

Modular construction is an economical and efficient construction that reduces time and costs by manufacturing units in factories and constructing them on site. Currently, the demand for modular construction is increasing not only abroad but also domestically. As the demand for modular construction increases, a lot of development and research on connections between modular units are being conducted. Connections between modular units should be quick and simple to assemble when assembling units on site, and should be in a form that allows each unit to be connected regardless of direction. In addition, it must be able to exert sufficient strength against external loads. In this study, a connection between modular units using connecting steel plates and bolts was proposed, and the nonlinear behavior of the connection to external lateral force was analyzed through finite element analysis, and resistance performance was evaluated.

• The Journal of Advanced Prosthodontics
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• v.10 no.5
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• pp.388-394
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• 2018

PURPOSE. To measure axial displacement of different implant-abutment connection types and materials during screw tightening at the recommended torque by using a contact scanner for two-dimensional (2D) and three-dimensional (3D) analyses. MATERIALS AND METHODS. Twenty models of missing mandibular left second premolars were 3D-printed and implant fixtures were placed at the same position by using a surgical guide. External and internal fixtures were used. Three implant-abutment internal connection (INT) types and one implant-abutment external connection (EXT) type were prepared. Two of the INT types used titanium abutment and zirconia abutment; the other INT type was a customized abutment, fabricated by using a computer-controlled milling machine. The EXT type used titanium abutment. Screws were tightened at $10N{\cdot}cm$, simulating hand tightening, and then at the manufacturers' recommended torque ($30N{\cdot}cm$) 10 min later. Abutments and adjacent teeth were subsequently scanned with a contact scanner for 2D and 3D analyses using a 3D inspection software. RESULTS. Significant differences were observed in axial displacement according to the type of implant-abutment connection (P<.001). Vertical displacement of abutments was greater than overall displacement, and significant differences in vertical and overall displacement were observed among the four connection types (P<.05). CONCLUSION. Displacement according to connection type and material should be considered in choosing an implant abutment. When adjusting a prosthesis, tightening the screw at the manufacturers' recommended torque is advisable, rather than the level of hand tightening.

• Journal of Korean Society of Steel Construction
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• v.17 no.4 s.77
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• pp.459-467
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• 2005

This study focuses on the development of a new method of H-shaped beam-to-square column connection with an outer diaphragm and a field welding. The specific type of beam-to-column connection with an external stiffener, using field welding, is proposed. The structural behavior of this connection was examined experimentally. Two loading type tests were conducted under the experimental parameters given as details. First described was the symmetrical loading test, which supported both ends or a beam simply and applied a load from the column to the pend (What does this mean?) to investigate a fundamental characteristic of this connection. Further described was the anti-symmetrical loading test, which carried out simple support of the column'stop end and the column base, and applied a load from both ends of a beam to investigate the structural performance of this connection. From the results, it is clear that the external- stiffener-type connection proposed in this paper is the reliable connection method.

• The Korean Journal of Health Service Management
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• v.6 no.4
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• pp.153-163
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• 2012

The purpose of this study is to measure IPA(Importance Performance Analysis) of the hospital choice factors between internal and external customers at rural general hospital. This study was used 5 types of choice factor such as physical, human, accessibility, connection, and external image. Also, this study was used IPA which can be applied to identify the strengths and weaknesses quality attributes from customers' viewpoint by simultaneously evaluating importance and performance. IPA was assessed using a sample of 98 patients and 96 internal employees who work at C general hospital in Chunkcheongbuk-do. Data were collected with self-administered questionnaires from February 13 to March 30 in 2012 and analyzed SPSS 18 by using frequency, paired t-test and scatter plot graph. The results of IPA show that "Keep up the good work" quadrant was human factor and "Low Priority" quadrant was physical and connection factors between internal and external customers. The finding of this study will be applied to improve human service quality in administrative department of hospital. Also, this study presents primary data for correct decision making to authorities of local hospitals that have concern about hospital strategy. The implications of this study are discussed and areas for future research are presented.

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.105-111
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• 2019

PURPOSE. Limited data is available regarding the differences for possible microleakage problems and fitting accuracy of zirconia versus titanium abutments with various connection designs. The purpose of this in vitro study was to investigate the effect of connection design and abutment material on the sealing capability and fitting accuracy of abutments. MATERIALS AND METHODS. A total of 42 abutments with different connection designs [internal conical (IC), internal tri-channel (IT), and external hexagonal (EH)] and abutment materials [titanium (Ti) and zirconia (Zr)] were evaluated. The inner parts of implants were inoculated with $0.7{\mu}L$ of polymicrobial culture (P. gingivalis, T. forsythia, T. denticola and F. nucleatum) and connected with their respective abutments under sterile conditions. The penetration of bacteria into the surrounding media was assessed by the visual evaluation of turbidity at each time point and the number of colony forming units (CFUs) was counted. The marginal gap at the implant- abutment interface (IAI) was measured by scanning electron microscope. The data sets were statistically analyzed using Kruskal-Wallis followed by Mann-Whitney U tests with the Bonferroni-Holm correction (${\alpha}=.05$). RESULTS. Statistically significant difference was found among the groups based on the results of leaked colonies (P<.05). The EH-Ti group characterized by an external hexagonal connection were less resistant to bacterial leakage than the groups EH-Zr, IT-Zr, IT-Ti, IC-Zr, and IC-Ti (P<.05). The marginal misfit (in ${\mu}m$) of the groups were in the range of 2.7-4.0 (IC-Zr), 1.8-5.3 (IC-Ti), 6.5-17.1 (IT-Zr), 5.4-12.0 (IT-Ti), 16.8-22.7 (EH-Zr), and 10.3-15.4 (EH-Ti). CONCLUSION. The sealing capability and marginal fit of abutments were affected by the type of abutment material and connection design.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.4
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• pp.544-561
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• 2005

Purpose : This study was to assess the loading distributing characteristics of implant systems with internal connection or external connection under vertical and inclined loading using finite element analysis. Materials and methods : Two finite element models were designed according to type of internal connection or external connection The crown for mandibular first molar was made using cemented abutment. Each three-dimensional finite element model was created with the physical properties of the implant and surrounding bone This study simulated loads of 200N at the central fossa in a vertical direction (loading condition A), 200N at the centric cusp tip in a 15$^{\circ}$ inward inclined direction (loading condition B), or 200N at the centric cusp tip in a 30$^{\circ}$ outward inclined direction (loading condition C) respectively. Von Mises stresses were recorded and compared in the supporting bone, fixture, abutment and abutment screw. Results : 1. In comparison with the whole stress or the model 1 and model 2, the stress pattern was shown through th contact of the abutment and the implant fixture in the model 1, while the stress pattern was shown through the abutment screw mainly in the model 2. 2. Without regard to the loading condition, greater stress was taken at the cortical bone, and lower stress was taken at the cancellous bone. The stress taken at the cortical bone was greater at the model 1 than at the model 2, but the stress taken at the cortical bone was much less than the stress taken at the abutment, the implant fixture, and the abutment screw in case of both model 1 and model 2. 3. Without regard to the loading condition, the stress pattern of the abutment was greater at the model 1 than at the model 2. 4. In comparison with the stress distribution of model 1 and model 2, the maximum stress was taken at the abutment in the model 1. while the maximum stress was taken at the abutment screw in the model 2. 5. The magnitude of the maximum stress taken at the supporting bone, the implant fixture, the abutment, and the abutment screw was greater in the order of loading condition A, B and C. Conclusion : The stress distribution pattern of the internal connection system was mostly distributed widely to the lower part along the inner surface of the implant fixture contacting the abutment core through its contact portion because of the intimate contact of the abutment and the implant fixture and so the less stress was taken at the abutment screw, while the abutment screw can be the weakest portion clinically because the greater stress was taken at the abutment screw in case of the external connection system, and therefore the further clinical study about this problem is needed.

• Korea Journal of Hospital Management
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• v.17 no.3
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• pp.83-98
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• 2012

The purpose of this study is to investigate IPA(Importance Performance Analysis) of the hospital choice factor between internal and external customers at S general hospital. This study was used 5 types of choice factors such as physical, interpersonal, accessibility, connection, and image. This study was used Importance Performance Analysis which can be applied to identify the strengths and weaknesses attributes from hospital customers' viewpoint. The sample was selected 116 patients and 97 internal employees for S hospital in Seoul. Data were collected with self-reported questionnaires from April 1 to 29 in 2012 and analyzed by paired t-test, scatter plot graph. The result of the study was that the perceptional gaps between internal and external consumers were existed in physical, connection and image factors, except interpersonal, accessibility. The "Keep up the good work" quadrant was interpersonal factor, and the "Low Priority" quadrant was accessibility. The findings of this study will be applied to make hospital strategic decision making and to improve marketing service quality in administrative department of hospital.

• Health Policy and Management
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• v.23 no.3
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• pp.281-288
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• 2013

Background: The purpose of this study is to grasp the factors forming hospital image and to measure evaluation of internal and external customers towards hospital choice factors. Methods: This study is based 4 types of choice factor such as physical, human, accessibility, and connection. Data were assessed using 98 patients and 96 internal employees who work at A general hospital in Seoul and 116 patients and 97 internal employees at B general hospital in Chunkcheongbuk-do. Data were collected with self-administered questionnaires from February 17 to April 29 in 2012 and analyzed SPSS ver. 18.0 by using frequency, t-test, analysis of variance, correlation, and multiple regression. Results: The results of this study show that factors affecting hospital image is significant different between internal and external customers of hospital A and B. Expecially the finding of this study will be applied to improve connection factors in administrative department of hospital for hospital image. Conclusion: This study presents primary data for correct decision making to authorities of local hospitals that have concern about marketing strategy for hospital image.