• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.101-109
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• 1997

An analytical procedure on the base of the substructure synthesis and assumed modes method is developed to investigate the flexibility effect of bladed disk assembly on vibrational modes of flexible rotor system. In modeling the system, Coriolis forces, gyroscopic moments, and centrifugal stiffening effects are taken into account. The coupled vibrations between the shaft and bladed disk are then extensively investigated through the numerical simulation of simplified models, with varying the shaft rotational speed and the pretwist and stagger angles of the blade. It is found that the Coriolis and inertia forces and the inertia torque, which are induced by the one nodal diameter modes of the bladed disk and vary depending upon the stagger and pretwist angles, lead to the coupled motions of the shaft and the bladed disk.

• 한국의료질향상학회지
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• 제18권1호
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• pp.37-55
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• 2012

Objectives : This study was conducted to evaluate the effect of fixed critical pathway with emr (electronic medical record) on the length of hospital stay, the cost and quality of care provided to gastrectomy patients in a university hospital and to develop flexible critical pathway with emr which can be used excluded or drop-out patients. Methods : Thirty-eight patients with gastrectomy were included as case group and Thirty-four patients included as control group. The comparison between control and case with using fixed critical pathway were done. To develop and to evaluate usefulness of flexible critical pathway with flexible data base, simulation was done for flexible critical pathway with drop-out patients. Result : The major results of this study were as follows: There were no significant differences in patient clinical conditions and no sign of deterioration of quality from critical pathway. The length of hospital stay was 11 days in control group, 8 days in path group(P<0.01). The total costs during the hospital stay were reduced in path group. However the cost per day was significantly increased from reduction of hospital stay(554,352 won in control, 645,669 won in path group). One hundred percentage of drop out patients(60) in the simulation of flexible critical pathway was successful. Conclusion : Computerized critical pathway reduced the length of hospital stay, total hospital costs and resource utilization without harming quality of patient care. The flexible critical pathway program can be used as one of the powerful management tools for reducing the practice variations and increasing the efficiency of care process and decreasing the workload of doctors and nurses in Korean hospital settings.

• Journal of Korean Dental Science
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• 제15권1호
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• pp.9-18
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• 2022

Purpose: The purpose of this study was to evaluate whether three-dimensional (3D)-printed flexible denture resin has suitable mechanical properties for use as a thermoplastic denture base resin material. Materials and Methods: A total of 96 specimens were prepared using the 3D printed flexible denture resin (Flexible Denture). Specimens were designed in CAD software (Tinkercad) and printed through a digital light-processing 3D printer (Asiga MAX UV). Post-polymerization process was conducted according to air exposure or glycerin immersion at 35℃ or 60℃ and for 30 or 60 minutes. The maximum flexural strength, elastic modulus, 0.2% offset yield strength, and Vickers hardness of 3D-printed flexible denture resin were assessed. Result: The maximum flexural strength ranged from 64.46±2.03 to 84.25±4.32 MPa, the 0.2% offset yield strength ranged from 35.28±1.05 to 46.13±2.33 MPa, the elastic modulus ranged from 1,764.70±64.66 to 2,179.16±140.01 MPa, and the Vickers hardness ranged from 7.01±0.40 to 11.45±0.69 kg/mm². Conclusion: Within the limits of the present study, the maximum flexural strength, 0.2% offset yield strength, elastic modulus, and Vickers hardness are sufficient for clinical use under the post-polymerization conditions of 60℃ at 60 minutes with or without glycerin precipitation.

• 대한치과보철학회지
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• 제60권4호
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• pp.347-353
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• 2022

상악 완전 무치악과 하악 양측 후방 무치악 상태의 환자에서 전통적인 의치를 제작하는 방법은 흔히 볼수 있는 치료 방법이다. 그러나 장기적으로 볼 때 이와 같은 구강내 환경에서는 복합증후군(Combination syndrome)이라는 합병증이 발생할 수 있다. 이때 임플란트를 동반한 국소의치(Implant Assisted Removable Partial Denture, IARPD)의 적용으로 치조골 보존과 함께 Combination syndrome의 예방을 도모할 수 있다. 본 증례에서는 무치악 부위에 임플란트의 추가 식립 시 국소의치의 움직임에 의해 최후방 지대치에 가해지는 응력을 줄일 수 있으므로 금속이 아닌 레진 클라스프를 계획하였고 flexible 의치 레진을 사용하였다. 상악 총의치, 하악 flexible IARPD를 계획하여 최소한의 비용과 수술로서 심미적, 기능적인 장기적 예후를 얻어 보고하고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.1177-1181
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• 1995

Fixtures are devided into special purpose fixtures, modular fixtures and general purpose fixtures. In this paper, the database of modual fixtures for flexible manufacturing systems is estabilished. Modular fixtures are classified into base plates, supporting elements, locating elements, clamping elements and accessories. Also the concept for the modular fixture design expert system is proposed.

• 한국응용과학기술학회지
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• 제34권2호
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• pp.280-288
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• 2017

에너지 저장 매체는 소형화, 고효율화 및 그린에너지 정책에 부합하면서 연구개발이 진행되고 있으며 유연성과 신축성을 갖는 디스플레이나 웨어러블 전자기기의 발전에 상응하는 에너지 저장 매체의 개발이 시급한 상황으로 이를 실현 할 수 있는 물질가운데, 탄소나노 재료중의 하나인 그래핀과 그래핀 하이브리드와 같은 뛰어난 전기화학적 특성을 지니고 있는 나노 재료가 각광을 받고 있다. 또한 슈퍼커패시터와 배터리 및 연료전지 등과 같은 에너지 저장 소자에 응용하기 위한 연구가 활발하게 진행 중에 있으며, 여러 가지 에너지 저장 매체 중 단시간에 고출력을 구현하고 장시간 신뢰성을 갖추며, 빠른 충 방전 순환특성을 가지는 슈퍼커패시터는 차세대 에너지원으로 많은 관심을 받고 있다. 본 연구에서는 플렉시블한 특성을 갖는 그래핀과 전도성 고분자 하이브리드 전극을 기반으로 하는 슈퍼커패시터를 개발하고자 하였으며 환원된 그래핀 옥사이드/폴리피롤 복합재료를 이용하여, 전기화학적 특성을 최대화 하였다. 그 결과 굽힘 시험 전 전극의 초기 용량값은 $198.5F\;g^{-1}$ 이었으며, 500번의 굽힘 시험 후 $128.3F\;g^{-1}$로 감소하는 것을 확인하였으나, 전극의 초기 전기 용량 값의 65 %의 성능을 유지하였다.

• 대한전자공학회논문지
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• 제11권4호
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• pp.1.1-11
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• 1974

변경의 Parameter를 제어 함으로써 임의의 조합논리함수를 이차원가변논리회로로 실현하는 일반적이고 조직적인 방법을 개발하였다. n변수-n출력 조합논리회로의 진리치표를 상태할당에 의해서 상태가의 변환으로 포착하여 이를 다치일변수 영리수수의 실현문제로 취급하였다. 이 다위일변수 함수집합이 정규결합연산에 환하여 반군을 이룬다는 사실에 착안하여 3개의 기저함수를 정의하고 이 기저함수에 의하여 임의의 다치일변수함수를 생성하는 기저함수렬의 조직적 구성법을 구하였다. 기저함수를 실현하는 기본회로를 단위회로의 일차원 배열로 구성하고 오직 하나의 기본회로만으로 3개의 기저함수외에도 몇개의 기저함수의 계열과 또 기저함수의 역함수를 실현하도록 하였다. 이 기본회로를 이차원으르 배열하고 변경의 parameter만을 적절히 설정 함으로써 임의의 조합논리회로를 실현하는 알고리즘을 구성하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.128-135
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• 2006

This paper presents a finite element method to analyze the free vibration of a flexible HDD composed of the spinning disk-spindle system with fluid dynamic bearings(FDBs), the head-suspension-actuator with pivot bearings, and the base plate with complicated geometry. Experimental modal testing shows that the proposed method well predicts tue vibration characteristics of a HDD. This research also shows that even the vibration motion of the spinning disk corresponding to half-speed whirl and the pure disk mode are transferred to a head-suspension-actuator and base plate through the air bearing and the pivot bearing consecutively. The proposed method can be effectively extended to investigate the forced vibration of a HDD and to design a robust HDD against shock.

• 한국소음진동공학회논문집
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• 제17권1호
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• pp.24-32
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• 2007

This paper presents a finite element method to analyze the free vibration of a flexible HDD composed of the spinning disk-spindle system with fluid dynamic bearings(FDBs), the head-suspension-actuator with pivot bearings, and the base plate with complicated geometry. Experimental modal testing shows that the proposed method well predicts the vibration characteristics of a HDD. This research also shows that even the vibration motion of the spinning disk corresponding to half-speed whirl and the pure disk mode are transferred to a head-suspension-actuator and base plate through the air bearing and the pivot bearing consecutively. The proposed method can be effectively extended to investigate the forced vibration of a HDD and to design a robust HDD against shock.

• Steel and Composite Structures
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• 제47권3호
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• pp.339-353
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• 2023

The primary objective of the current study is to optimize and evaluate the seismic performance of steel momentresisting frame (MRF) structures considering soil-structure interaction (SSI) effects. The structural optimization is implemented in the context of performance-based design in accordance with FEMA-350 at different confidence levels from 50% to 90% by taking into account fixed- and flexible-base conditions using an efficient metaheuristic algorithm. Nonlinear response-history analysis (NRHA) is conducted to evaluate the seismic response of structures, and the beam-on-nonlinear Winkler foundation (BNWF) model is used to simulate the soil-foundation interaction under the MRFs. The seismic performance of optimally designed fixed- and flexible-base steel MRFs are compared in terms of overall damage index, seismic collapse safety, and interstory drift ratios at different performance levels. Two illustrative examples of 6- and 12-story steel MRFs are presented. The results show that the consideration of SSI in the optimization process of 6- and 12-story steel MRFs results in an increase of 1.0 to 9.0 % and 0.5 to 5.0 % in structural weight and a slight decrease in structural seismic safety at different confidence levels.