• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.233-237
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• 2014

In this paper, the finite element modeling of the RK4 rotor kit system (RK4) and then frequency analysis and transient analysis, and was compared with the actual experimental results. RK4 manufactured by General Electric for the purpose of education and research. It is composed of two shaft, Two shaft is connected using a flexible coupling, one disk is mounted. The analytical model is modeled by using the ANSYS finite element analysis program commercially available. Based on impact hammer test results, material properties and the stiffness of the bearing and coupling was tuned. Considering the operating conditions and the vibration response of the analytical model were compared with experimental results.

• Architectural research
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• 제14권1호
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• pp.3-9
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• 2012

Owing to the advent of ubiquitous computing technologies, the concept of Intelligent Environments has emerged, as an alternative approach to overcome the limitation of the built environment. Intelligent Environments can be more responsive to user-and context-specific human activities by automatically and dynamically modifying their settings without explicit human intervention. However, the conventional approach to the development of Intelligent Environments has mainly focused on the technical issues without paying much attention to the dynamic interrelationship between the user and the built environment. Therefore, differing or conflicting needs of multiple simultaneous users remain unresolved. The objective of this study is to present types of environmental conflicts and their resolution through agent collaboration and negotiation. For the demonstration and validation of the conflict resolution process, a set of hypothetical test cases is simulated in a 3D test environment. The result of the case simulations shows that the proposed approach is computationally feasible and applicable to the development of Intelligent Environments, and, furthermore, it can overcome the drawback of the conventional approach.

• International Journal of Aeronautical and Space Sciences
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• 제18권2호
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• pp.222-235
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• 2017

In this study, finite element modeling was used to predict the material properties of tri-axially braided textile composite. The model was made based on an experimental test specimen which was also used to compare the final results. The full interlacing of tows was geometrically modelled, from which repeating parts that make up the whole braid called unit cells were identified based on the geometric and mechanical property periodicity. In order to simulate the repeating nature of the unit cell, periodic boundary conditions were applied. For validation of the method, a reference model was analyzed for which a very good agreement was obtained. Material property calculation was done by simulating uniaxial and pure shear tests on the unit cell. The comparison of these results with that of experimental test results showed an excellent agreement. Finally, parametric study on the effect of number of plies, stacking type (symmetric/anti-symmetric) and stacking phase shift was conducted.

• 한국대기환경학회지
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• 제16권1호
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• pp.69-77
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• 2000

This paper summerizes the results of the first proficiency testing program for achieving the analytical quality assurance of anions and metal ions in air borne particles in Korea. This program covered the chemical testing of anions(Cl-, NO3-, SO42-) and metals(Fe, Pb, Zn) in qeueous solution. The exercies was conducted by the Measurement & Analysis Committee of Korean Society for Atmospheric Environment(KOSAE). Pilot lab. was Division of Chemical Metrology and Materais Evaluation in Korea Research Institute of Standards and Science(KRISS). A total of 11 laboratories participated in the program. Two samples of 100mL in low density polyehylene bottles were supplied to participating laboratories. The proficiency testing results were interpreted by two graphical methods, Youden polt and x-Charts(control chart).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.136-139
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• 2001

KEPRI successfully developed and installed RTDS(Real-Time Digital Simulator) during March 2001. The simulator will be used to study interactive simulation of electromagnetic & electromechanical and validation of protective & control systems. In this paper. the authors will present an overview of real-time digital simulator and its characteristic features. Special emphasis will be placed to the installation test results. This paper also addresses some key issues on the accuracy, reliability flexibility and its practical uses for real-time power simulation.

• 대한기계학회논문집A
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• 제24권8호
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• pp.1991-1999
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• 2000

This research has been performed to reveal the hysteresis phenomena of the hunting motion in a railway passenger car having a bolster. Since linear analysis can not explain them, bifurcation analysis is used to predict its outbreak velocities in this paper. However bifurcation analysis is attended with huge computing time, thus this research proposes more effective numerical algorithm to reduce it than previous researches. Stability of periodic solution is obtained by adapting of Floquet theory while stability of equilibrium solutions is obtained by eigen-value analysis. As a result, linear and nonlinear critical speed are acquired. Full scale roller rig test is carried out for the validation of the numerical result. Finally, it is certified that there are many similarities between numerical and test results.

• 대한화학회지
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• 제58권6호
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• pp.543-552
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• 2014

A quantitative structure activity relationship (QSAR) study is performed for modeling and prediction of oral bioavailabilities of 216 diverse set of drugs. After calculation and screening of molecular descriptors, linear and nonlinear models were developed by using multiple linear regression (MLR), artificial neural network (ANN), support vector machine (SVM) and random forest (RF) techniques. Comparison between statistical parameters of these models indicates the suitability of SVM over other models. The root mean square errors of SVM model were 5.933 and 4.934 for training and test sets, respectively. Robustness and reliability of the developed SVM model was evaluated by performing of leave many out cross validation test, which produces the statistic of $Q^2_{SVM}=0.603$ and SPRESS = 7.902. Moreover, the chemical applicability domains of model were determined via leverage approach. The results of this study revealed the applicability of QSAR approach by using SVM in prediction of oral bioavailability of drugs.

• Nuclear Engineering and Technology
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• 제44권7호
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• pp.719-726
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• 2012

The object of this work is the validation and assessment of the TRACE v5.0 code using the scaled test ATLAS1 facility in the context of a DVI2 line break. In particular, the experiment selected models the 50%, 6-inch break of a DVI line. The same experiment was also adopted as a reference test in the ISP-503. The ISP-50 was proposed to, and accepted by, the OECD/NEA/CSNI due to its technical importance in the development of a best-estimate of safety analysis methodology for DVI line break accidents. In particular, the behavior of the two-phase flow in the upper annulus downcomer was expected to be complicated. What resulted was the need for relevant models to be implemented into safety analysis codes, in order to predict these thermal hydraulic phenomena correctly.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.396-399
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• 2007

풍력 블레이드용으로 설계된 에어포일에 대하여 풍동 시험을 수행하였다. 설계된 에어포일의 레이놀즈수 범위에 맞추고자 코드 길이 40cm의 모델에 대하여 유속 17m/s, 35m/s, 50m/s에 대하여 에어포일 표면에서의 압력과 에어포일 뒤쪽 레이크에서의 압력을 측정하였다. 이를 통하여 설계에 사용된 기법의 타당성과 설계된 에어포일에 대하여 설계 변수에 대한 실질적 만족도에 대하여 평가하였다. 이와 더불어 표면 거칠기에 대한 모사를 위하여 트립도트를 부착하여 시험을 수행하였다. 이를 통하여 레이놀즈수와 표면 거칠기에 따른 에어포일의 성능 및 유동 변화 특성에 대하여 파악 할 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1240-1245
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• 2000

A Spacecraft container must afford the satellite a relatively benign thermal, vibration, and particle environment that is oblivious to the extreme temperatures, sand, dust, vibrations and shocks that can accompany the transportation. This paper discusses the extensive yet simple vibration test and validation of one such spacecraft container used for KOMPSA T-1 spacecraft, which was transported from KARl Taejon, Korea to Vandenberg Air Force Base(VAFB) on September 30 and launched successfully December 21, 1999. The test results are presented and compared with the design requirement. The dynamic characteristics of shipping container, such as natural frequencies, satisfied the design requirement and showed that shipping container was well. designed and manufactured. This kind of know-how will help to develop the next generation of Korean space program, such as KOMPSAT-2 and Korean tele-communication satellite.