• 대한치과보철학회지
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• 제46권3호
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• pp.290-297
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• 2008

STATEMENT OF PROBLEM: Implant-supported fixed cantilever prostheses are influenced by various biomechanical factors. The information that shows the effect of implant number and position of cantilever on stress in the supporting bone is limited. PURPOSE: The purpose of this study was to investigate the effect of implant number variation and the effect of 2 different cantilever types on stress distribution in the supporting bone, using 3-dimensional finite element analysis. MATERIAL AND METHODS: A 3-D FE model of a mandibular section of bone with a missing second premolar, first molar, and second molar was developed. $4.1{\times}10$ mm screw-type dental implant was selected. 4.0 mm height solid abutments were fixed over all implant fixtures. Type III gold alloy was selected for implant-supported fixed prostheses. For mesial cantilever test, model 1-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 1-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 1-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with mesial cantilever were simulated. And then, 155N oblique force was applied to the buccal cusp of second premolar. For distal cantilever test, model 2-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 2-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 2-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with distal cantilever were simulated. And then, 206N oblique force was applied to the buccal cusp of second premolar. The implant and superstructure were simulated in finite element software(Pro/Engineer wildfire 2.0). The stress values were observed with the maximum von Mises stresses. RESULTS: Among the models without a cantilever, model 1-1 and 2-1 which had three implants, showed lower stress than model 1-2 and 2-2 which had two implants. Although model 2-1 was applied with 206N, it showed lower stress than model 1-2 which was applied with 155N. In models that implant positions of models were same, the amount of applied occlusal load largely influenced the maximum von Mises stress. Model 1-1, 1-2 and 1-3, which were loaded with 155N, showed less stress than corresponding model 2-1, 2-2 and 2- 3 which were loaded with 206N. For the same number of implants, the existence of a cantilever induced the obvious increase of maximum stress. Model 1-3 and 2-3 which had a cantilever, showed much higher stress than the others which had no cantilever. In all models, the von Mises stresses were concentrated at the cortical bone around the cervical region of the implants. Meanwhile, in model 1-1, 1-2 and 1-3, which were loaded on second premolar position, the first premolar participated in stress distribution. First premolars of model 2-1, 2-2 and 2-3 did not participate in stress distribution. CONCLUSION: 1. The more implants supported, the less stress was induced, regardless of applied occlusal loads. 2. The maximum von Mises stress in the bone of the implant-supported three unit fixed dental prosthesis with a mesial cantilever was 1.38 times that with a central pontic. The maximum von Mises stress in the bone of the implant-supported three-unit fixed dental prosthesis with a distal cantilever was 1.59 times that with a central pontic. 3. A distal cantilever induced larger stress in the bone than a mesial cantilever. 4. A adjacent tooth which contacts implant-supported fixed prosthesis participated in the stress distribution.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1250-1253
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• 2008

As a reinforcement technique, the application of removable soil nailing has been extended to solve the public grievance of typical soil nailing such as the geotechnical environmental problem and invasion of adjacent land. In the case of removable soil nailing, pullout capacity of the nail depends on the adhesive strength of a fixed socket. Because the existing fixed socket is made from a plastic product, the strength of a socket is less than a steel bar and then the yield failure by abrasion and deformation is occurred on the steel bar-socket contact surface. In this study, therefore, experimental analysis from laboratory test of a removable soil nail equipped with steel socket, improving the adhesive strength of steel bar-socket connection is performed to estimate the increase effect of pullout capacity of a soil nail.

• 한국군사과학기술학회지
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• 제16권1호
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• pp.40-47
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• 2013

By virtue of Rec. ITU-R P.1546 and geography information system, interference analysis for the fixed wireless system and radar has been presented based upon the frequency-distance rules with minimum coupling loss, and a comprehensive methodology for assessing interoperability between systems was examined in terms of received signal, protection ratio, frequency dependent rejection. Also to find the antenna gain from a discrimination angle, a useful S-I plane was introduced based on signal and interference vectors derived from the real map with geographic information. To show some computational results, geography information on the map was taken for the given area, and field strength and path profile were illustrated for the radar and fixed wireless system operating at 2.7 GHz, for convenience. In addition the interference effect of receiver was also checked as a function of radar beam direction including protection ratio and frequency dependent rejection. The developed interference analysis can be actually applied to evaluate interoperability for wireless systems in the VHF and UHF bands.

• Communications for Statistical Applications and Methods
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• 제15권6호
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• pp.1003-1011
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• 2008

Mixed-effect Poisson regression models are widely used for analysis of correlated count data such as those found in longitudinal studies. In this paper, we consider kernel extensions with semiparametric fixed effects and parametric random effects. The estimation is through the penalized likelihood method based on kernel trick and our focus is on the efficient computation and the effective hyperparameter selection. For the selection of hyperparameters, cross-validation techniques are employed. Examples illustrating usage and features of the proposed method are provided.

• 국제지역연구
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• 제14권1호
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• pp.203-219
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• 2010

최근 글로벌 금융위기로 미 달러의 신인도 하락에 따른 환율의 불안정성은 많은 다른 국가들에게 경기침체와 교역 감소 등 많은 경제적 피해를 주고 있다. 하지만 유로화를 사용하고 있는 유로존(eurozone) 회원국들은 제2위의 기축통화국에 따른 유로존 우산효과로 경제적 손실이 비교적 작았다. 이런 이유로 1999년 1월 12개국으로 출범한 유로존은 2009년 슬로바키아의 가입과 함께 덴마크, 스웨덴, 영국 등이 회원국 가입을 희망하고 있고 갈수록 확대될 전망이다. 국가들 간 통화통합에 따른 단일통화 사용은 동종 상품의 가격비교가 용의해져 경쟁효과 발생에 따른 소비자의 후생증진이 이루어진다. 또한 통화교환비용과 환리스크 제거로 국가 간 교역의 역기능적 요소가 사라져 교역 증대가 이루어진다. 따라서 유럽 국가들이 유로화 도입으로 어느 정도의 교역효과가 유발되는지 분석해 보기 위해 임의효과모형(random effect estimation)과 고정효과모형(fixed effect estimation)을 사용하였다.

• 대한환경공학회지
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• 제35권6호
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• pp.449-455
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• 2013

소규모 하수처리시스템에 다양한 반송비와 고정식 담체를 적용하여 합성폐수에서 질소, 인의 제거를 검토하였다. 담체를 첨가 시 질소의 제거율은 40.1%에서 65.1%로 증가하였으나 COD와 인의 제거에는 영향이 없었다(<5%). 반송을 통해 유량을 2배(2Q)로 증가시킨 경우 질소의 제거율은 7% 정도가 증가하였으나, 인 제거율은 반송비가 증가됨에 따라 31.8에서 26.6%로 감소하였다. 무산소조에서 담체에 부착된 미생물은 약 73.4 $mg/cm^2$로 존재하였으며, FISH분석 결과 탈질 미생물인 Pseudomonas aeruginosa 존재 (약 58%)를 확인하였다.

• 한국항행학회논문지
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• 제21권5호
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• pp.428-434
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• 2017

최근 이동형 글로벌 광대역 통신 및 위성기반의 양방향 인터넷 서비스에 대한 수요가 증가함에 따라 ESIM(Earth Station in Motion)이라는 새로운 형태의 위성 터미널이 개발되고 있다. 이 시스템은 ITU-R Resolution 158(WRC-15)에서 FSS(Fixed Satellite Service) 업링크에 27.5-29.5 GHz 대역사용을 고려하고 있어 동일 대역에 이미 분배된 FS와의 간섭분석에 대한 연구가 요구되고 있다. 이에 본 논문에서는 FS(Fixed Service) 무선국 방향으로 보어사이트를 향하는 ESIM의 방위각을 일양분포의 랜덤특성을 고려하여 FS 수신안테나의 -10 dB 빔폭 내의 평균 수신전력 및 간섭기준 초과확률에 대해 이론해석과 시뮬레이션 분석을 수행하였다. 그 결과 이론해석의 타당성을 보여주며, 동일 대역의 FS를 보호하기 위해서는 ESIM 이동 터미널의 보어사이트에 대한 이동경로 기울기 각도, 운영시간, 이동속도 등을 종합적으로 고려해서 간섭기준이 마련되어야 한다.

• 한국병원경영학회지
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• 제9권2호
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• pp.102-127
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• 2004

The objective of this study is to analyze a current trend of and relating factors on profitability of the Korean Public Corporation Medical Centers(KPCMCs, hereinafter, hospitals) in Korea. There are 34 hospitals in Korea as of 2004. Among these hospitals some are red ink hospitals, others are black inks in terms of profitability. Data were collected by Korea Health Industry Development Institute(KHIDI) Statistics for Hospital Management 2000-2002 and Ministry of Health and Welfare(MOHW) financial data of public hospitals which was planned to coordinate public health care services roadmap in the long run. The samples are 32 hospitals. Profitability was measured in the aspect of profit rate with normal profit to total assets, and normal profit to gross revenues as dependent variables in respective. Independent variables were classified by general factors, i.e., location, intern/resident training, period of opening, number of beds, and managerial factors(current ratio, fixed ratio, liability to total assets, total assets turnover, personnel costs, materials cost, administrative cost), and finally factors related to patient treatment(average length of stay, bed occupancy rate, admission ratio of outpatients). The methods of analysis are correlation and multiple regression analysis. This study shows firstly, a lot of hospitals are optimal current ratio. Hospitals in upper 100% current ratio are 81.2%. And the personnel cost in total costs are high. Secondly, the trend of normal profit to gross revenues of hospitals are deteriorating gradually. And lastly, as a result of multiple regression analysis, the factors had on significant effect on normal profit to total assets are fixed ratio(+), liability to total assets(-), bed occupancy rate(+), admissions of outpatients(+), etc. And the factors had on significant effect on normal profit to gross revenues are current ration(+), fixed ratio(+), personnel cost(-), administrative expenses(-), admissions of outpatients(+), etc. In conclusion, to improve the profitability of hospitals, the efforts to reduce personnel cost and average length of stay might be needed. And also beds utilization rate need to be increased.

• Computers and Concrete
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• 제25권3호
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• pp.255-266
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• 2020

This study presents comparation of fixed and viscos boundary condition effects on three-dimensional earthquake response and performance of a RCC dam considering linear and non-linear response. For this purpose, Cine RCC dam constructed in Aydın, Turkey, is selected in applications. The Drucker-Prager material model is considered for concrete and foundation rock in the nonlinear time-history analyses. Besides, hydrodynamic effect was considered in linear and non-linear dynamic analyses for both conditions. The hydrodynamic pressure of the reservoir water is modeled with the fluid finite elements based on the Lagrangian approach. The contact-target element pairs were used to model the dam-foundation-reservoir interaction system. The interface between dam and foundation is modeled with welded contact for both fixed and viscos boundary conditions. The displacements and principle stress components obtained from the linear and non-linear analyses are compared each other for empty and full reservoir cases. Seismic performance analyses considering demand-capacity ratio criteria were also performed for each case. According to numerical analyses, the total displacements and besides seismic performance of the dam increase by the effect of the viscous boundary conditions. Besides, hydrodynamic pressure obviously decreases the performance of the dam.

• Clinical and Experimental Reproductive Medicine
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• 제20권1호
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• pp.65-70
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• 1993

To maintain a good sperm motility is one of the key factors for the successful artificial insemination in retrograde ejaculation, and the sperm motility has been shown to be affected by various environmental factors, including change in pH and osmolarity. Herein we have analyzed the effect of change in pH and osmolarity in urine and normal saline on sperm motility by Sperm Quality Analyzer and Makler counting chamber. Semen, which sampled by masturbation from a 28 year old male and showed normal finding on semen analysis, was used for this study. The results were as follows: 1. When osmolarity was fixed to 300mOsm, pH did not show a definite effect on the sperm moility. However, the motility was generally a bit better in alkaline urine and saline than in acid, particularly than in pH 5.0. 2. When pH was fixed to 7.5, sperm motility was best in urine and saline of 300mOsm. Hyperosmolarity had more adverse.effect on the motility than hypoosmolarity. 3. The sperm motility was worse in the urine than in saline under the same pH and osmolarity. In conclusion, osmolarity has a definite effect on sperm motility, where as pH has relatively little effect. And certain components of urine other than pH and osmolarity might affect the sperm motility.