• 한국항공우주학회지
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• 제38권4호
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• pp.376-381
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• 2010

일반적으로 기체 구조물 개발시 운용조건에서의 구조설계 해석 검증 및 구조강도확인을 위해서 구조강도시험이 수행된다. 본 논문에서는 구조시험 하중부가방법 중 응력집중에 의해 파손되기 쉬운 재료를 기체 지지구조로 사용하고자 할 때 구조물 표면에 공기압을 이용하여 국부적 응력집중을 피하면서 분포하중을 부가할 수 있는 새로운 외력부가장치의 개발에 대하여 기술하였다. 본 장치는 부드러운 재질의 하중전달용 매개체를 이용하여 구조물 표면에 손상을 주지 않고 외력을 전달할 수 있으며, 임의형상 구조물에 대하여 쉽게 응용이 가능하다. 본 장치를 이용하여 평판구조물과 곡면구조물에 대하여 외력부가구조강도시험을 성공적으로 수행함으로써 적용시험기법의 타당성을 입증하였다.

• Spatial Information Research
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• 제19권5호
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• pp.47-52
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• 2011

최근 국지적 강풍 및 태풍에 의한 피해규모가 증가하고 있다. 국토의 70%이상이 산악지형인 우리나라에서는 산악지형의 특성에 따른 풍속의 변화를 적절하게 반영한 풍하중 산정이 필요하며 건축구조기준(2009)에서도 이를 명시하여 설계과정에 반영하도록 하고 있다. 그러나 실제 구조물 설계 시 지형적 특성을 고려한 풍속지형계수를 산정하기 위해서는 현지 지형측량 등 여러 가지 어려운 점을 가지고 있다. 본 논문에서는 수치지형도에서 TIN보간법을 이용한 수치표고모델(DEM)을 제작하고, ESRI(R)ArcObjectTM와 프로그래밍 언어인 비주얼 베이직(Visual Basic)을 사용하여 풍속지형계수를 자동적으로 산정할 수 있는 인터페이스를 설계 구현하였다. 이를 도심지에 위치한 산악지형에 적용함으로써 풍속지형계수 산정 인터페이스의 실용성을 점검하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2290-2295
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• 2005

In this paper, it is developed simulator system of 3 D.O.F parallel robot for educate of expertness. This simulator system is composed of three parts ? 3 D.O.F parallel robot, controller (hardware) and software. First, basic structure of the robot is 3 active rotary actuator that small geared step motor with fixed base. An input-link is connected to this actuator, and this input-link can connect two ball joints. Thus, two couplers can be connected to the input-link as a pair. An end-plate, which is jointed by a ball joint, can be connected to the opposite side of the coupler. A sub-link is produced and installed to the internal spring, and then this sub-link is connected to the upper and bottom side of the coupler in order to prevent a certain bending or deformation of the two couplers. The robot has the maximum diameter of 230 mm, 10 kg of weight (include the table), and maximum height of 300 mm. Hardware for control of the robot is composed of computer, micro controller, pulse generator, and motor driver. The PC used in the controller sends commands to the controller, and transform signals input by the user to the coordinate value of the robot by substituting it into equations of kinematics and inverse kinematics. A controller transfer the coordinate value calculated in the PC to a pulse generator by transforming it into signals. A pulse generator analyzes commands, which include the information received from the micro controller. A motor driver transfer the pulse received from the pulse generator to a step motor, and protects against the over-load of the motor Finally, software is a learning purposed control program, which presents the principle of a robot operation and actual implementation. The benefit of this program is that easy for a novice to use. Developed robot simulator system can be practically applied to understand the principle of parallel mechanism, motors, sensor, and various other parts.

• 전산구조공학
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• 제9권1호
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• pp.151-159
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• 1996

구조용 콘크리트의 비선형 거동을 예측하기 위하여, 압축강도 연화현상, 거시적 및 회전균열모델등의 내용을 포함하고 있는 압축장 응력장 이론(CFT)에 근거한 유한요소법이 개발/제시되었다. 또한, 이와 관련하여 CFT가 암시하는 탄젠트 및 세칸트 재료강성이 반복계산해법의 관점에서 정의/논의되었다. 최종적으로 계산상의 효율성 증대 및 최대하중 이후의 거동 포착에 주안점을 두어 초기재료 강성을 채택한 변위증분법 논리 및 빠른 수렴을 위한 Over-Relaxtion방법이 Isoparametric계의 8-Node요소에 포함/유도되었다. 이와 같이하여 제시된 비선형 해석 프로그램 NASCOM은 응력 혼돈지역에 위치하는 콘크리트 평면요소의 하중 지지능력, 탄성범위 이후의 변형 특성, 균열양상 및 보강근의 항복범위등의 예측을 가능하게 하였다. NASCOM의 제한된 검증을 위하여, Cervenka의 판넬 시험결과에 대한 하중지지능력 및 변형이력등을 예측한 결과가 전체적인 의미에서 실험결과와 상응하는 일치를 나타내었다.

• Journal of Periodontal and Implant Science
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• 제44권1호
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• pp.39-47
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• 2014

Purpose: Peri-implantitis, a clinical term describing the inflammatory process that affects the soft and hard tissues around an osseointegrated implant, may lead to peri-implant pocket formation and loss of supporting bone. However, this imprecise definition has resulted in a wide variation of the reported prevalence; ${\geq}10%$ of implants and 20% of patients over a 5- to 10-year period after implantation has been reported. The individual reporting of bone loss, bleeding on probing, pocket probing depth and inconsistent recording of results has led to this variation in the prevalence. Thus, a specific definition of peri-implantitis is needed. This paper describes the vast variation existing in the definition of peri-implantitis and suggests a logical way to record the degree and prevalence of the condition. The evaluation of bone loss must be made within the concept of natural physiological bony remodelling according to the initial peri-implant hard and soft tissue damage and actual definitive load of the implant. Therefore, the reason for bone loss must be determined as either a result of the individual osseous remodelling process or a response to infection. Methods: The most current Papers and Consensus of Opinion describing peri-implantitis are presented to illustrate the dilemma that periodontologists and implant surgeons are faced with when diagnosing the degree of the disease process and the necessary treatment regime that will be required. Results: The treatment of peri-implantitis should be determined by its severity. A case of advanced peri-implantitis is at risk of extreme implant exposure that results in a loss of soft tissue morphology and keratinized gingival tissue. Conclusions: Loss of bone at the implant surface may lead to loss of bone at any adjacent natural teeth or implants. Thus, if early detection of peri-implantitis has not occurred and the disease process progresses to advanced peri-implantitis, the compromised hard and soft tissues will require extensive, skill-sensitive regenerative procedures, including implantotomy, established periodontal regenerative techniques and alternative osteotomy sites.

• 한국과학교육학회지
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• 제1권1호
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• pp.73-88
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• 1978

The survey is intended to improve science education by the analysis of problems produced in the following nine aspects (objectives, contents, materials, inquring methods, teaching methods, teachers, children, evalutions, admininative supports) during the past five years often the revision of new science curriculum. 1. View for science education. 1) The teacher's and children's view for science education can be seen renewed, being different from the old one. 2) Inquring method in learning and teaching began to take firm root and children came to know that it is the only way to study science. 3) Writers think that the new science education has stepped into the stage of being fixed to a considerable degree. 2. The aspect of administrative policy. 1) The amount of materials in possession is small and the present materials are lacking in solidity and precision. 2) Class room teacher's over load with miscellaneous things is a difficult problem to solve. 3) The shortage of the printed materials and books for children and teachers has an influence on the development of inquring method. 4) It causes cramming to examine all children at the same time by paper test. 5) It is more desirable to appoint qualified teacher only for science teaching. 3. Contents of science curriculum. 1) In current science textbooks. There can be found some contents which are difficult for teachers to understand and not in accordance with the reality of Korea. Therefore, it is imperative that contents of science textbooks should be reexamined. 2) As it is hard to teach concepts of reciprocal action and to prepare materials with teaching of the system of biological concepts, the teaching of contents is likely to be a cramming. 4. The aspect of in-service education. 1) It is obsolutely predominant reation that in-service education is making a great contribution to class room teaching. 2) As adiministrators' policy for science education has a great effect, in-service education for their enlightenment is needed.

• 한국간호교육학회지
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• 제6권1호
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• pp.48-63
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• 2000

This study was designed and undertaken to find out the degree of powerlessness, perception of health and cognitive level of elderly home residents and to determine the factors influencing powerlessness, perception of health and cognitive level. The data were collected from October 1st to 20th, 1998. The subjects in this study were 271 elderly home residents over the age 60 living in Taejon city. The study tool for measuring powerlessness was developed by S.E. Chung(1998), the other for measuring perception of health was a self-rating scale defined by Mossey & Shapiro (1982), and the tool for measuring cognitive level was developed by Kahn, Goldfarb, Pollack and Peck(1960). Data were analysed for percentage, mean, t-test, and ANOVA using the SPSS program. The results of this study were as follows ; 1. The degree of powerlessness, perception of health and cognitive level was scored above the median. 2. The degree of the elderly' powerlessness was statistically significantly different in three demographic variables; sex, one's state of health compared to other elderly' and living expense load. 3. Perception of one's health was statistically significantly different in four demographic variables; sex, marital status, educational level and monthly money. 4. Cognitive level of the elderly was statistically significantly different in three demographic variables; age, educational level and one's health of state compared to other elderly' health. In conclusion, the factors influencing the elderly' powerlessness, perception of health and cognitive level generally were age, sex, their economic independence, marital status, and educational level. Also, this study indicates that social welfare for the elderly could be effective in reducing their powerlessness and enhancing their health of state and cognitive level.

• 한국직업건강간호학회지
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• 제27권1호
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• pp.36-47
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• 2018

Purpose: This study aimed to examine the effects of interpersonal relationship ability, job stress, and stress coping type on the turnover intention of nurses in the early stage of their careers. Methods: Data were collected from 136 early stage nurses from two general hospitals and one tertiary hospital in Chungbuk province. An early stage nurse was defined as the nurse with a work experience of 3 to 36 months. The collected data were analyzed using independent t-test, one-way ANOVA, Mann-Whitney U test, Person's correlation coefficient, and stepwise multiple regression. Results: It was seen that turnover intention had a negative correlation with interpersonal competency (r=-.20, p=.020) and a positive correlation with job stress (r=.56, p<.001). Job stress due to work over load, inadequate compensation and working environment, interpersonal relationship ability, and length of clinical career were significant factors influencing turnover intention (p<.05). These variables explained for 50.4% of the variance in turnover intention. Conclusion: It is necessary to develop an interpersonal relationship ability improvement program to decrease turnover intention among early stage nurses by helping them to successfully adapt to their job. Moreover, it is important to bring about continuous improvements in terms of provision of adequate workload and appropriate rewards, and creation of a suitable work environment to reduce the job stress of early stage nurses.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.745-748
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• 2008

과거 건설 구조물은 사용 하중을 견딜만한 성능과 사용성, 부식에 대한 저항성 정도만이 요구되었다. 그러나 9.11 사건 이후 이러한 관점은 바뀌어, 폭발에 의한 충격 하중 및 그와 동시에 발생할 수있는 화재로 인한 열에 견딜 수 있는 구조물의 저항 성능이 기본적인 요구 조건으로써 중요시되고있다. 전 세계가 연일 테러의 위협 아래 놓여있는 현 시점에서 구조물의 내폭 성능은 매우 중요한 부분이라 할 수 있다. 이에 본 연구에서는 기존의 건설 재료로써 폭넓게 사용되고 있는 시멘트 복합체 혹은 콘크리트에인장 강도 및 연성이 뛰어난 FRP composite을 결합시켜 내폭 성능이 우수하고 기존 구조물 및 신설구조물에 모두 시공이 가능한 최적화된 분절 복합체(Segmented Composite) 및 층 구조(Layered Structure)를 개발하고, 그 성능을 평가하고자 한다. 이러한 내폭 성능의 향상을 통해, 열과 충격 하중, 동하중 및 high strain에 의한 구조물의 붕괴를 줄이고 붕괴 시점을 보다 늦출 수 있다면, 이로인해 발생되는 인명 피해 및 경제적 손실을 최소화시킬 수 있을 것이다.

• 연구논문집
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• 통권27호
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• pp.87-99
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• 1997

Present paper describes on/off design performance of a 50KW turbogenerator gas turbine engine for hybrid vehicle application. For optimum design point selection, relevant parameter study is carried out. The turbogenerator gas turbine engine for a hybrid vehicle is expected to be designed for maximum fuel economy, ultra low emissions, and very low cost. Compressor, combustor, turbine, and permanent-magnet generator will be mounted on a single high speed (82,000 rpm) shaft that will be supported on air bearings. As the generator is built into the shaft, gearbox and other moving parts become unnecessary and thus will increase the system's reliability and reduce the manufacturing cost. The engine has a radial compressor and turbine with design point pressure ratio of 4.0. This pressure ratio was set based on calculation of specific fuel consumption and specific power variation with pressure ratio. For the given turbine inlet temperature, a rather conservative value of $1100^\circK$ was selected. Designed mass flow rate was 0.5 kg/sec. Parametric study of the cycle indicates that specific work and efficiency increase at a given pressure ratio and turbine inlet temperature. Off design analysis shows that the gas turbine system reaches self operating condition at N/$N_{DP}$ = 0.53. Bleeding air for turbine stator cooling is omitted considering low TIT and for a simple geometric structure. Various engine performance simulations including, ambient temperature influence, surging at part load condition. Transient analysis were performed to secure the optimum engine operating characteristics. Surge margin throughout the performance analysis were maintained to be over 80% approximately. Validation of present results are yet to be seen as the performance tests are scheduled by the end of 1998 for comparison.