• 소음진동
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• 제6권5호
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• pp.595-605
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• 1996

If the control force designed on the basis of the mathematical model with parameter errors is applied to control the actual system, the closed-loop performance of the actual system will be degraded depending on the degree of the errors, In this study, the effect of parameter errors on the robustness of several natural controls has been analyzed and compared. Every asymptoic stability condition for the natural controls has been derived using Lyapunov approach, and the characteristics of the stability conditions has also been compared. The extent of deviation of the closed-loop performance from the designed one for the natural controls is derived using operator techniques, and evaluated by numerical method. It has been found that the optimal control, acceleration feedback control, and acceleration-position feedback control among the considered natural controls would be robust one with respect to the parameter errors.

• 한국생활과학회지
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• 제12권5호
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• pp.619-634
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• 2003

The purpose of this study was to the real situation of the safety education in the kindergarten by investigating the actual condition of the safety education and kindergarten teachers' knowledge about it. Questionnaire was adopted to obtain data required for pertinent analysis. The subjects were 234 kindergarten teachers located in Choongnam and Daejeon province. SPSSWIN v10.0 was utilized to calculate percentage, mean and standard deviation and to conduct t-test, one-way ANOVA and Duncan's multiple range test. The main results of this study were as follows. There was a significant difference between the actual condition of the safety education and kindergarten teachers' knowledge about it according to demographic variables. Especially, these differences were due to teachers' academic career, age, teaching experience, and the experience of bringing up children by themselves. The importance of the safety education must be emphasized. There were urgent needs to develop the way of teaching and the program about the safety education.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.1040-1043
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• 2004

The purpose of this study is to present a fundamental data for evaluating aircraft noise of building site development. By the field experiments and an predicted equal noise level contour using the INM program, actual condition in the building site development arranged district was investigated. In order to get the results, Analysis of factors effected on noise level, sound level on the rate of increase to aircraft demand and difference on the aircraft noise levels according to floor level in apartment house was carried out.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.567-571
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• 1989

This paper describes the improvement of thermal power plant turbine control system by analyzing nonlinear characteristics. The turbine control depends on the frequency variation and boiler condition. The nonlinearity of turbine control is the result of governor/valve properties, steam condition and boiler thermal unbalance. Nonlinear analysis is divided into two; main steam valve position - turbine output anal governor response. Of course, every analysis must be done on considering plant operating condition. In this paper, after analyzing turbine control nonlinearity by numerical method and actual results, the sensitive operating load which corresponds to frequency is proposed, on guarranteed boiler stability. This idea is implemented at Pyung Tack thermal power plant, and the practical results are showed.

• 한국의학물리학회지:의학물리
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• 제28권4호
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• pp.164-170
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• 2017

One of the methods to consider the effect of respiratory motion of a tumor target in radiotherapy is to establish a treatment plan with the internal target volume (ITV) created based on an accurate analysis of the target motion displacement. When this method is applied to intensity modulated radiotherapy (IMRT), it is expected to yield a different treatment dose distribution under the motion condition according to the IMRT method. In this study, we prepared ITV-based IMRT plans with conventional IMRT using fixed gantry angle beams, RapidArc using volumetric modulated arc therapy, and tomotherapy using helical therapy. Then, the variation in dose distribution caused by the target motion was analyzed by the dose measurement in the actual motion condition. A delivery quality assurance plan was prepared for the established IMRT plan and the dose distribution in the actual motion condition was measured and analyzed using a two-dimensional diode detector placed on a moving phantom capable of simulating breathing movements. The dose measurement was performed considering only a uniform target shape and motion in the superior-inferior (SI) direction. In this condition, it was confirmed that the error of the dose distribution due to the target motion is minimum in tomotherapy. This is thought to be due to the characteristic of tomotherapy that treats the target sequentially by dividing it into several slices. When the target shape is uniform and the main target motion direction is SI, it is considered that tomotherapy for the ITV-based IMRT method has a characteristic which can reduce the dose difference compared with the plan dose under the target motion condition.

• 한국도로학회논문집
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• 제17권6호
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• pp.37-45
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• 2015

PURPOSES : The purpose of this study is to validate the design criteria of the concrete modular road system, which is a new semi-bridge-type concept road, through a comparison of numerical analysis results and actual loading test results under static axial loads. METHODS : To design the semi-bridge-type modular road, both the bridge design code and the concrete structural design code were adopted. The standard truck load (KL-510) was applied as the major traffic vehicle for the design loading condition. The dimension of the modular slab was designed in consideration of self-weight, axial load, environmental load, and combined loads, with ultimate limit state coefficients. The ANSYS APDL (2010) program was used for case studies of center and edge loading, and the analysis results were compared with the actual mock-up test results. RESULTS : A full-scale mock-up test was successfully conducted. The maximum longitudinal steel strains were measured as about 35 and 83.5 micro-strain (within elastic range) at center and edge loading locations, respectively, under a 100 kN dual-wheel loading condition by accelerating pavement tester. CONCLUSIONS : Based on the results of the comparison between the numerical analysis and the full-scale test, the maximum converted stress range at the edge location is 32~51% of the required standard flexural strength under the two times over-weight loading condition. In the case of edge loading, the maximum converted stresses from the Westergaard equation, the ANSYS APDL analysis, and the mock-up test are 1.95, 1.7, and 2.3 times of that of the center loading case, respectively. The primary reason for this difference is related to the assumption of the boundary conditions of the vertical connection between the slab module and the crossbeam module. Even though more research is required to fully define the boundary conditions, the proposed design criteria for the concrete modular road finally seems to be reasonable.

• 한국농촌건축학회논문집
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• 제13권1호
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• pp.55-62
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• 2011

The purpose of this study is to clarify the actual condition of real certification schools of environment-friendly architecture per ecological environment elements through extracting ecological environment elements which is possible to analyze in quantity certification standards of environment friendly architecture. As the method of this study, firstly, certification as an examination on certification system of environment-friendly architecture, summary of certification system of environment-friendly architecture and eco-school pilot model project, ecological environment elements which is possible for quantitative analysis of ecological environment certification standards were extracted. Secondly, actual condition of ecological environment elements per school grade by collecting actual data of certification schools environment-friendly architecture were analyzed. The average of ecological area ratio was 24.5 percent in case of this certification regardless of school grade and region and it was analyzed that the natural based green area ratio was 22.9 percent, bio-tope area ratio was 0.60 percent and ecological learning places area ratio was 0.39 percent.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.434-437
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• 2003

아파트 공사에서 계획기성은 영업부티 시공단계에 걸쳐 공사기간, 분양가 산정, 중도금 납부시점 결정, 인허가 관련, 기성지급 기준, 계획대비 실직비교 관리 등에 활용되므로, 다수 사업 참여자간의 이해 및 프로젝트의 성공에 지속적으로 영향을 미치는 핵심적인 관리요소이다. 그러나 대단지 아파트 공사의 특징인 다수 건물 동시 시공으로 인한 공정 액티비티 과다발생으로 인하여 공정표를 상세하고 작성하고 자원을 분개하여 계획기성을 정확하게 산출하고 관리하는데 어려움을 겪고 있는 실정이다. 본 연구에서는 실태조사를 통하여 계획기성 산출과 관리에 관한 문제점을 분석하고 그 원인을 파악함으로써 계획기성을 체계적으로 산출하기 위한 향후 개선방향을 제시하고자 한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1859-1863
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• 2007

A new type of a fretting wear tester has been designed and developed in order to simulate the actual vibration behavior of a nuclear fuel rod for springs/dimples in room temperature. When considering the actual contact condition between fuel rod and spring/dimple, if fretting wear progress due to the flow-induced vibration (FIV) under a specific normal load exerted on the fuel rod by the elastic deformation of the spring, the contacting force between the fuel rod and dimple that were located in the opposite side should be decreased. Consequently, the evaluation of developed spacer grids against fretting wear damage should be performed with the results of a cell unit experiments because the contacting force is one of the most important variables that influence to the fretting wear mechanism. Therefore, it is necessary to develop a new type of fretting test rig in order to simulate the actual contact condition. In this paper, the development procedure of a new fretting wear tester and its performance were discussed in detail.

• 한국콘텐츠학회논문지
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• 제8권3호
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• pp.190-196
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• 2008

오늘날 우리는 자살사례를 쉽게 접할 수 있으며, 한국 사회에서 자살은 중요한 사회문제로 대두되었다. 우리나라의 자살 추세를 살펴보면, 연간 자살자수는 1990년 3,157명에서 2006년 10,688명에 이르기까지 지속적인 증가세를 보였다. 인구 10만명당 자살률은 1991년 9.1명에서 점진적으로 증가해오다가 1996년과 1997년에 각각 13.9명과 14.1명으로 소폭 상승하였으며, 외환위기를 맞은 1998년에 19.9명으로 대폭 상승하여 정점에 이르렀다. 그 이후 다시 감소하기 시작하여 2000년 14.6명과 2001년 15.5명을 기록하여 안정세를 되찾는 듯 하였으나, 다시 경기가 악화되기 시작하면서 2002년 19.1명, 2003년 24.1명, 2004년 25.2명, 2005년 26.1명으로 계속 증가하였다. 2006년에는 2000년 이후 6년 만에 자살률이 감소되었지만 23.0명으로 여전히 높은 실정이다.