• 한국소음진동공학회논문집
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• 제19권4호
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• pp.347-354
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• 2009

Frequency analysis is one of the most useful way to analyze response signal for the purpose of grasping the dynamic characteristics of system through Fourier transformation. Although it is very effective way for frequency analysis, it is hard to analyze out a specific sound or vibration component which is correlated with others. In this thesis, source contribution analysis tool for NI-PXI equipment is developed with LabVIEW using coherences of MISO(multiple-input single-output) model. For the purpose of examining propriety of developed tool, simulation is performed with several correlated signals that have different frequency range. After checking the OCF(ordinary coherence function) and PCF(partial coherence function) of the each signal for concerned frequency domain, an experiment is conducted on an evaporator that cause the principal noise of a refrigerator. This developed tool will be expected to build up more convenient and serviceable measurement system.

• 한국터널공학회:학술대회논문집
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• 한국터널공학회 2005년도 학술발표회 논문집
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• pp.225-232
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• 2005

The construction of parallel tunnel by using the shield TBM method was increased recently. Accordingly the application and the propriety of the parallel shield TBM tunnels were studied through domestic and foreign construction cases herein. Also the behavior of tunnel structure and ground was evaluated by a numerical analysis with various ground conditions and the distance between the parallel tunnels. As a result, it was concluded that a deep investigation as well as a ground reinforcement was required with a ratio(L/D) of the distance between the parallel tunnels(L) to tunnel outer diameter(D) less than 0.5 because the Interference phenomenon was expected to occur. And the appropriateness of the application method of parallel shield TBM tunnel was validated through the 2-dimensional numerical analysis simulated the process of excavation after the ground reinforcement in the starting area of the OOO construction site with the ratio(L/D) of 0.35.

• 대한전기학회논문지
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• 제37권12호
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• pp.839-846
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• 1988

전기기기의 와류분포를 해석하고자 항때 자기벡터포텐셜을 이용한 2차원적 해석법을 적용하면 해석영성내의 와류의 크기는 구할수 있지만 그 분포 양상은 알 수 없다. 이러한 문제점을 해결하기 위해 전류 벡터포텐셜을 도입하여 지배방정식을 유도하였으며 이에 유한요소법을 적용하여 2차원적 와류분포해석을 시도하였다. 그리도 시간술분항의 취급에는 시간영성가중계산법을 적용하였으며 이에 따른 알고리즘을 도출하였다. 또한 위에 방법을 해석해가 좌우하는 모델 및 와류에 의해 구동토오크가 발생하는 군상적산전력계 의 알루미늄 원판에 적용하여 해석한 결과 그 타당성 및 유용성을 입증할 수 있었다.

• 전력전자학회논문지
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• 제2권4호
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• pp.19-27
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• 1997

본 논문은 스위치 턴·오프시의 손실을 줄이기 위해서 소프트 스위칭 기법인 ZVS(Zero-Voltage Switching)을 도입하여 회로의 동작 해석과 설계에 관해 기술하였다. 또한, 제안 회로의 해석은 무차원화 파라메타를 도입하여 범용성 있게 기술하였고, 운전 특성을 스위칭 주파수와 제 파라메타에 따라 특성 평가를 하였다. 이론 해석에서 얻은 특성값을 기초로 한 회로 설계 기법의 일 예를 제시하였다. 첨가해서, 실험을 통해 이론 해석의 정당성을 입증하였으며, 향후 유도 가열 조리기 등의 전원 시스템에 응용가능성을 보여주고 있다.

• 한국산학기술학회논문지
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• 제8권1호
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• pp.110-115
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• 2007

도시지역의 우수관거는 최근 발생 빈도가 높은 국지적 집중호우에 대하여 배수기능 수행이 취약한 실정이며, 특히 저지대 역류 현상에 따른 침수피해는 도시 설계 및 관거 개량사업에 있어서 반드시 해결해야할 사항이다. 본 연구에서는 강우분석을 통한 도시유출특성을 고려하여 현행 우수관거의 설계빈도에 대한 통수능력을 검토하였으며, 방류하천의 계획홍수위 영향을 고려하여 관거 내 역류 및 저지대 침수량을 분석함으로써 도시유역의 원활한 내수배제를 위한 유수지 및 펌프장의 설치 여부 및 규모 산정을 위한 기초자료를 제공하였다.

• 전기학회논문지
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• 제57권3호
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• pp.390-397
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• 2008

Permanent Magnet Linear Synchronous Motor (PMLSM) has high efficiency, high energy density, and high control-ability. But, the detent force always is produced by the structure of slot-teeth. There are the disadvantages such as noise and vibration of the apparatuses are induced and the control ability is curtailed because detent force acts as thrust ripple. Therefore, the detent force reduction is an essential requirement in PMLSM. Generally, the method, skewing permanent magnet or slot-teeth, is used to reduce the detent force. But the thrust is decreased at the same time. If permanent magnet is skewed, the lateral force which operates as the perpendicular direction of skew direction is generated in linear guide of PMLSM. So, V-skew model is proposed for the reduction of lateral force. The lateral force acts as braking force in linear motion guide, and it has bad influence to the characteristics of PMLSM. However, these problems will not be solved by 2-dimensional Finite Element Analysis (FEA). So, in this paper 3-dimensional FEA is applied to analyze the PMLSM where permanent magnet is skewed and has overhang. The detent force and thrust characteristics considering skew and overhang effects of permanent magnet are analyzed by 3-dimensional FEA and the results are compared with experimental values to verify the propriety of analysis.

• 소성∙가공
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• 제14권8호통권80호
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• pp.675-680
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• 2005

This study was aimed at the design of the dies for the automobile part for the engine oil leakage prevention using the computer simulation to shorten the period of production, on the basis of the process planning which was designed by the field experts. In the computer simulation,'eesy-2-form' of 2D FEM simulation package and 'eesy-DieOpt' have been used, which are the commercial process analysis and die design program. Through the simulation of 'eesy-2-form', we could know the propriety of the forming process, the inner pressure of the die and the suitable fitting pressure between the insert and the sleeve which was not showing any positive tangential stresses in the insert. Through the simulation of 'eesy-DieOpt', we could know the number of the stress ring, the diameter ratios, the stresses of the die, the shrink fitting tolerance and temperature in the condition of the already determined maximum outer die diameter of the multi-stage former. The validity of the die design using the computer simulation was analyzed by the experiments and the results were satisfactory. As the results of this study, the new and easy die design system for cold forging has been developed.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권5호
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• pp.309-317
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• 2004

This paper suggested the vibration characteristic improvement by variation mode of ring type ultrasonic motor. Design for the piezoelectric ceramic and elastic body of stator were calculated by the finite element method(FEM) that consider the resonance frequency, vibration mode and coupling efficiency etc. Through the result of vibration analysis from 6 order mode to 8 mode, the 7 order mode was gained very an excellent results that it was the coupling efficient, minimum power loss and bending vibration value. Here over 7 order mode, this paper was acquired that an output current for input voltage was very a large increased results. The result of vibration calculation, from thickness 0.5[mm] to 2[mm], knew the fact that the vibration displacement at 0.5[mm] is an high value too. From such result, this paper was manufactured the ultrasonic motor of outer diameter 5O[mm] , inter 22[mm] having the about 43.86[KHz] resonance frequency. We have gated that a simulation result is 42.2[KHz] and an experiment result is 43.86[KHzl The propriety of this paper was established though comparison. investigation of simulation and experiment result.

• 한국실내디자인학회논문집
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• 제25호
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• pp.245-252
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• 2000

Since the twentieth century, common exhibitions have experienced display replacements and apace alterations. As a result, not only the visual space background of the spectators but the structure systems and positions of the construction space have also been changed. With regards to common zones of the exhibition space, appropriate harmonization of spectators space, aisle space, and media space are closely related the effectiveness and propriety of display arrangement. A number of preceeding researches suggest exhibition first, construction next, regarding the order of the construction and exhibition of the museums and art galleries. However, a majority of the exhibition hall constructions in Korea have not been carried away based on these models. Thus, disharmony of constructions and exhibition space structures have caused numerous problems. The purpose of this research is to seek the countermeasures that can be used in the stage of planning for the museum constructions and exhibition space by suggesting, based on the above mentioned points, the development of the indicators and analyzing methods to understand the structural attributes of the common exhibition space through space syntax method and multivariate analysis.

• 동서간호학연구지
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• 제11권1호
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• pp.25-32
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• 2005

Purpose: This study was aimed to identify the factors that related the dietary behavior in coronary artery disease patients and to made the data for nursing which is thought to improve the dietary behavior. Method: The study population was the coronary artery disease patients who were treated at outpatient base. The study method was the dietary behavior, diet self-efficacy, perceived-healthy behavior, social support measurement & characteristics. All of the above tool was validated for its composition propriety and confidence. The statistical analysis was done by SPSS PC 11.0 program. and frequency, percentage, mean, standard deviation, Pearson's correlation was used for analysis. Results: The score of dietary behavior in the coronary artery disease patients was 4.57 point. The score of perceived-benefits was the highest among the association factor(point) and the score of perceived-barriers(m=2.78), diet self-efficacy(m=5.12), social support(m=4.86 point), exercise and chest pain. Conclusion: The development of the program for the efficient dietary education that prevents the progression of the coronary artery disease is needed.