• 대한치과보철학회지
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• 제43권4호
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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.

• 한국병원경영학회지
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• 제17권3호
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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.

• 대한전자공학회논문지
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• 제27권8호
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• pp.1239-1249
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• 1990

In this paper, using the neural network design techniques, an adaptive Mahalanobis distance classifier(AMDC) is designed. This classifier has three layers: input layer, internal layer and output layer. The connection from input layer to internal layer is fully connected, and that from internal to output layer has partial connection that might be thought as an Oring. If two ormore clusters of patterns of one class are laid apart in the feature space, the network adaptively generate the internal nodes, whhch are corresponding to the subclusters of that class. The number of the output nodes in just same as the number of the classes to classify, on the other hand, the number of the internal nodes is defined by the number of the subclusters, and can be optimized by itself. Using the method of making the subclasses, the different patterns that are of the same class can easily be distinguished from other classes. If additional training is needed after the completion of the traning, the AMDC does not have to repeat the trainging that has already done. To test the performance of the AMDC, the experiments of classifying 500 Hangeuls were done. In experiment, 20 print font sets of Hangeul characters(10,000 cahracters) were used for training, and with 3 sets(1,500 characters), the AMDC was tested for various initial variance \ulcornerand threshold \ulcorner and compared with other statistical or neural classifiers.

• 보건의료산업학회지
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• 제6권4호
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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.

• 대한치과보철학회지
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• 제50권2호
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• pp.119-127
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• 2012

연구 목적: 본 연구는 3차원 유한요소분석을 통해 특징적인 내부연결구조를 갖는5종의 임플란트의 고정체와 지대주의 연결방식에 따른 응력분산을 알아보고자 하였다. 연구 재료 및 방법: 본 실험을 위한 유한요소모델은 하악 제1대구치부에 임플란트가 식립되고 상부구조물로 3형 금합금을 사용하는 것으로 가정하였다. 응력분산은 200 N의 하중이 교합면의 중심, 중심에 1.5 mm 외측, 중심에서 3.0 mm 외측에 수직으로 가해지고 임플란트의 장축과 $30^{\circ}$의 각도로 경사하중이 가해지도록 하여 분석하였다. 유한요소모델에 대한 해석작업은 3G.Author (PlassoTech, California, USA)를 사용하여 이뤄졌다. 결과: 경사가 없는 내부계단 구조를 가지는 DAS tech의 임플란트의 경우, 내부연결구조를 갖는 다른 임플란트에 더 유리한 응력분산을 보였다. 하중이 임플란트 고정체의 외형선 이내에 가해지는 경우와 비교하여 외형선 바깥이나 경사력으로 전해지는 경우 더 높은 응력을 보였으며 하중조건과 관계없이 임플란트 고정체보다는 지대주에 더 큰 응력이 집중되었다. 결론: 교합력이 가해졌을 때 응력분산은 임플란트의 연결부의 형태와 하중이 가해지는 위치에 따라 달라졌으며 내부계단 구조를 가지는 DAS tech의 임플란트를 사용한 경우와 고정체의 외형선 이내에 하중이 가해졌을 경우에 더 유리한 응력분산을 보였다.

• 한국지반신소재학회논문집
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• 제12권1호
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• pp.101-107
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• 2013

최근 들어 토목 구조물에도 친환경성과 경제성이 강조되고 있으며 콘크리트 블록대신 soilbag을 전면벽으로 이용하는 절토사면 보강공법이 활용되고 있다. 그러나 친환경적이고 경제적인 재료라 하더라도 안정성이 보장되지 않으면 구조물로써의 가치를 지닐 수 없다. Soilbag 옹벽의 안전성 검토를 위해 기존의 옹벽 설계프로그램인 MSEW를 사용하여 연결부에서의 인발저항, 파단, 인장응력과 내적, 외적 안전율을 산정하고 블록식 보강토 옹벽의 안전율 산정결과와 비교하였다. 연결부의 안전성을 평가할 수 있는 연결강도 감소계수를 차등 적용시켜 연결강도가 감소함에 따라 옹벽의 안전율을 검토하였고 soilbag 보강토 옹벽에서는 soilbag과 지오그리드 보강재의 연결재가 이동이 가능하기 때문에 전면구배의 변경이 자유로우므로 soilbag의 구배에 따른 안전율 변화도 확인하였다. 해석결과로부터 soilbag을 이용한 보강토 옹벽의 연결부 강도에 대한 안전율 및 내적, 외적안정에 대한 안전율을 비교 검토한 결과 전 영역에서 기준 안전율 이상임을 나타내었다.

• 대한심미치과학회지
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• 제19권1호
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• pp.42-58
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• 2010

• 구강회복응용과학지
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• 제33권2호
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• pp.114-118
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• 2017

목적: 이 연구의 목적은 타이타늄 구성요소를 가진 지르코니아 지대주가 내부연결 임플란트에 사용되었을 때 나사 풀림에 대해 알아보는 것이다. 열순환 후 타이타늄 소켓을 가진 지르코니아 지대주와 타이타늄 지대주의 나사 풀림과 제거력을 비교 분석하였다. 연구 재료 및 방법: 내측연결 임플란트와 내측연결 타이타늄 지대주, 타이타늄 소켓을 가진 외측연결 지르코니아 지대주를 준비하였다. 내부연결형 임플란트에 5개의 타이타늄 지대주를(대조군), 타이타늄 소켓을 가진 5개의 지르코니아 지대주(실험군)를 각각 연결하고 30 Ncm의 토크로 조인 후 열순환 처리 전후의 지대주 나사 제거력을 측정하였다. 각 시편들은 열순환 장치의 수조에서 $5^{\circ}C$와 $55^{\circ}C$의 물에 60초씩 교대로 2,000회의 열순환을 시행하였다. 각 시편의 나사 풀림을 조사하고 열순환 전후에 나사 제거력을 통계학적으로 분석하였다. 결과: 두 그룹 모두에서 열순환 후 지대주 나사 풀림을 보이지 않았다. 열순환 전후의 나사 제거력 차이는 대조군에서 $-1.34{\pm}2.53Ncm$, 실험군에서 $-1.26{\pm}2.06Ncm$ 로 나타났다. 독립표본 T 통계분석 결과 두 군간에 유의한 차이를 보이지 않았다(P > 0.05). 결론: 이 실험의 결과 내에서 내부연결 임플란트를 위한 지르코니아 지대주 내 타이타늄 소켓이 열순환 후 지대주 나사풀림에 타이타늄 지대주와 비교하여 유의한 영향을 나타내지 않았다.

• The Journal of Advanced Prosthodontics
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• 제8권5호
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• pp.388-395
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• 2016

PURPOSE. The purpose of this study was to evaluate the resistance to deformation under static overloading by measuring yield and fracture strength, and to analyze the failure characteristics of implant assemblies made of different titanium grades and connections. MATERIALS AND METHODS. Six groups of implant assemblies were fabricated according to ISO 14801 (n=10). These consisted of the combinations of 3 platform connections (external, internal, and morse tapered) and 2 materials (titanium grade 2 and titanium grade 4). Yield strength and fracture strength were evaluated with a computer-controlled Universal Testing Machine, and failed implant assemblies were classified and analyzed by optical microscopy. The data were analyzed using the One-way analysis of variance (ANOVA) and Student's t-test with the level of significance at P=.05. RESULTS. The group $IT4_S$ had the significantly highest values and group IT2 the lowest, for both yield strength and fracture strength. Groups $IT4_N$ and ET4 had similar yield and fracture strengths despite having different connection designs. Group MT2 and group IT2 had significant differences in yield and fracture strength although they were made by the same material as titanium grade 2. The implant system of the similar fixture-abutment interfaces and the same materials showed the similar characteristics of deformation. CONCLUSION. A longer internal connection and titanium grade 4 of the implant system is advantageous for static overloading condition. However, it is not only the connection design that affects the stability. The strength of the titanium grade as material is also important since it affects the implant stability. When using the implant system made of titanium grade 2, a larger diameter fixture should be selected in order to provide enough strength to withstand overloading.

• 구강회복응용과학지
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• 제21권1호
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• pp.1-14
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• 2005

The purpose of this study was to assess the loading distributing characteristics of implant prosthesis of internal connection system(ITI system) according to position and direction of load, under vertical and inclined loading using finite element analysis (FEA). The finite element model of a synOcta implant and a solid abutment with $8^{\circ}$ internal conical joint used by the ITI implant was constructed. The gold crown for mandibular first molar was made on solid 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 outside point of the central fossa with resin filling into screw hole in a vertical direction (loading condition B), 200N at the centric cusp in a $15^{\circ}$ inward oblique direction (loading condition C), 200N at the in a $30^{\circ}$ inward oblique direction (loading condition D) or 200N at the centric cusp in a $30^{\circ}$ outward oblique direction (loading condition E) individually. Von Mises stresses were recorded and compared in the supporting bone, fixture, and abutment. The following results have been made based on this study: 1. Stresses were concentrated mainly at the ridge crest around implant under both vertical and oblique loading but stresses in the cancellous bone were low under both vertical and oblique loading. 2. Bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. The magnitude of the stress was greater with the oblique loading than with the vertical loading. 3. An offset of the vertical occlusal force in the buccolingual direction relative to the implant axis gave rise to increased bending of the implant. So, the relative positions of the resultant line of force from occlusal contact and the center of rotation seems to be more important. 4. In this internal conical joint, vertical and oblique loads were resisted mainly by the implant-abutment joint at the screw level and by the implant collar. Conclusively, It seems to be more important that how long the distance is from center of rotation of the implant itself to the resultant line of force from occlusal contact (leverage). In a morse taper implant, vertical and oblique loads are resisted mainly by the implant-abutment joint at the screw level and by the implant collar. This type of implant-abutment connection can also distribute forces deeper within the implant and shield the retention screw from excessive loading. Lateral forces are transmitted directly to the walls of the implant and the implant abutment mating bevels, providing greater resistance to interface opening.