• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.113-116
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• 2000

The effect due to group delay and non linear characteristics in high speed data satellite channel was represented in this paper. Based on the modeling of group delay and non linear characteristics the performance was analyzed in ka band satellite channel. The group delay and non-linear characteristics in high speed data transmission severely affect the system performance. The more Eb/No is required to satisfy the required system performance. The optimum operating points of HDR satellite transmission system are implemented by considering analyzed results for channel characteristics

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.690-695
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• 2005

Flexible circular cantilever beams when excited externally introduce a lot of dynamic characteristics. The non-linear elements that these flexible beams develop include non-linearity due to inertia terms, spring, and damping. They show different characteristics of motion from each other. In the modes of lower order, the non-linearity due to spring is prevalent, while the non-linearity due to inertia Is prevalent in the modes of higher order. To analyze these effects the non-linear phenomena are analyzed experimentally. When the response characteristics of non-linear vibration are analyzed using autospectrum, it is possible to analyze the subharmonic and superharmonic mot ion by comparison. The phase change is analyzed using the method of phase portrait and the non-linear characteristics of response characteristics that are developed in flexible structures can be predicted and applied to the stage of design.

• 한국전자파학회논문지
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• 제12권4호
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• pp.600-610
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• 2001

본 논문에서는 초고속 위성통신 시스템의 채널 특성에 대한 성능 분석을 하였다. 고속 데이터 전송의 열화요인으로 작용하는 군지연과 비선형 분석을 통하여 다양한 전송 서비스를 제공하는 Ka 대역의 초고속 전송 시스템의 채널 성능 영향을 고찰하였다. 전송 데이터가 증가할수록 군지연과 비선형에 의한 영향은 증가하며, 군지연 선형 성분과 비선형의 AM-AM 성분이 시스템 성능 열화에 지배적으로 작용하는 것을 알 수 있었다. 고속 데이터에 따른 광대역 전송 대역폭으로 낮은 군지연과 이득 평탄도를 얻기가 어려우므로 주요 열화 요소를 등화하여 수십 Mbps에서부터 수백 Mbps 의 넓은 범위의 서비스를 동일 시스템에서 효과적으로 제공하여야 한다. 분석된 결과는 최적의 동작점을 갖는 초고속 위성통신 시스템을 설계하고 운용하는데 활용될 수 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.677-682
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• 2003

The non-linear dynamic characteristics of a semi-circular pipe conveying fluid are investigated when the pipe is clamped at both ends. To consider the geometric non-linearity for the radial and circumferential displacements, this study adopts the Lagrange strain theory for large deformation and the extensible dynamics based on the Euler-Bernoulli beam theory for slenderness assumption. By using the Hamilton principle, the non-linear partial differential equations are derived for the in-plane motions of the pipe, considering the fluid inertia forces as a kind of non-conservative forces. The linear and non-linear terms in the governing equations are compared with those in the previous study, and some significant differences are discussed. To investigate the dynamic characteristics of the system, the discretized equations of motion are derived form the Galerkin method. The natural frequencies varying with the flow velocity are computed fen the two cases, which one is the linear problem and the other is the linearized problem in the neighborhood of the equilibrium position. Finally, the time responses at various flow velocities are directly computed by using the generalized- method. From these results, we should to describe the non-linear behavior to analyze dynamics of a semi-circular pipe conveying fluid more precisely.

• 신재생에너지
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• 제7권3호
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• pp.74-82
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• 2011

Because concern on the problem of the limited energy is growing and the wind energy is considered as one of the biggest solutions, the researches on the wind energy and turbine are accomplished vigorously. The simulation tools on the non-linear characteristics of wind turbine system are various and it could describe the non-linear characteristics well but, the tool and methodology to apply non-linear control theory rarely exist. In this paper, the application procedure of sliding mode control theory to 2-DOF non-linear wind turbine system is suggested and the application results of it are also shown as compared with a torque loop control theory.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2006년도 춘계학술발표대회 논문집
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• pp.206-209
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• 2006

The concept of non-linearity, which has been derived from a scientific paradigm, has generated new discourse in formative arts. The non-linearity enables various new possibilities such as, generation of diverse and dynamic space, creation of non-geometric form and space, and the shape in the space as it is in nature. This study percepts and explains the concepts of non-linearity and their principles in space modeling in the field of interior design, in terms of the philosophy of fractal geometry. We also analyze cases, which shows trends and specific embodiments of non-linear space modeling. This study will provide perspectives on the non-linearity as a new methods in the space modeling. For the study, we review the concept and characteristics of non-linearity, by examining various literatures, and developed an analyzing tool which was used to study various cases of Western and Korean interior Design.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.584-587
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• 1992

Because linear motor directly drives linear motion, it does not need conversion equipment such as belt and gear. Especially linear pulse motor provide more precise positioning and large force of linear pulse motors. As current manufacture technic of linear pulse motor is much to be desired at home. This motor lay out to make use of computer aided design program, In this paper the experimental motor is 2-phases 4-poles hybrid pulse motor which has teeth per pole Simulation program is divided its function into 4 parts - air gap permeance analysis, permanent magnet & non-linear core operating point determine, winding configuration, leakage flux analysis. It is possible to make motor static and magnetic characteristics for this simulation program. Also, by varying input parameters of the program, experimental motor is to be compared to motor characteristics.

• 산업기술연구
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• 제29권B호
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• pp.17-23
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• 2009

In many cases, clustering algorithms have been used for extracting and discovering useful information from non-linear data. They have made a great effect on performances of the systems dealing with non-linear data. Thus, this paper presents a new approach called hierarchically structured clustering algorithm, and it is applied to the prediction system for non-linear time series data. The proposed hierarchically structured clustering algorithm (called HCKA: Hierarchical Cross-correlation and K-means clustering Algorithms) in which the cross-correlation and k-means clustering algorithm are combined can accept the correlationship of non-linear time series as well as statistical characteristics. First, the optimal differences of data are generated, which can suitably reveal the characteristics of non-linear time series. Second, the generated differences are classified into the upper clusters for their predictors by the cross-correlation clustering algorithm, and then each classified differences are classified again into the lower fuzzy sets by the k-means clustering algorithm. As a result, the proposed method can give an efficient classification and improve the performance. Finally, we demonstrates the effectiveness of the proposed HCKA via typical time series examples.

• 산업기술연구
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• 제18권
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• pp.233-240
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• 1998

In this study, ride sensitivity analysis of train with non-linear suspension elements is performed. Non-linear characteristics of springs and dampers for primary and secondary suspensions of a train is parameterized. Equation of motion of the train model is derived, and using the direct differentiation method, sensitivity equations are obtained. For a nominal ride quality performance index, sensitivity analysis with respect to various design parameters regarding non-linear suspension parameters is carried out.

• 한국터널지하공간학회 논문집
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• 제12권4호
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• pp.295-306
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• 2010

암석과는 달리 절리암반은 변형률 의존적 변형특성(탄성계수 및 감쇠비)을 나타낸다. 탄성파를 이용한 현장실험을 통해 미소변형률 수준에서 암반의 최대탄성계수를 얻을 수 있으며 이를 내진 설계에 반영하고 있으나, 미소 변형률 이상의 중변형률($10^{-4}{\sim}0.5%$) 영역의 동적거동에 대한 실험적인 규명과 이에 대한 수치적 적용은 전무한 실정이다. 본 연구에서는 변형률 의존적 전단탄성계수 및 감쇠비의 비선형 거동 특성을 반영하여 동적해석을 수행할 수 있는 FLAC3D 해석 모듈을 개발하였다. 리커 웨이브의 파동 변화를 분석하여 개발된 모듈에 대한 검증을 수행하였다. 절리 암반의 탄성파 전파특성과 동적 거동특성을 모사할 수 있는 절리암반 공진주 시험장비를 통하여 현장에서 채취한 절리암반의 변형률 의존적 전단탄성 계수의 감쇠 특성과 감쇠비의 증폭 특성을 획득하였다. 개발된 비선형 해석 모듈에 실험으로부터 획득된 거동 특성을 반영하여 수직구와 사갱의 접속부에 대한 내진 안정성 평가를 수행하였다. 내진해석 결과, 비선형 해석이 선형 해석보다 더 큰 연직변위와 수평변위 결과를 나타냈다. 라이닝의 휨압축응력은 수직구과 사갱의 접속부에서 집중되는 것으로 나타났으며 비선형해석의 경우 라이닝에 더 큰 휨압축응력이 발생되는 것으로 나타났다. 본 연구를 통하여 변형률 의존적 절리암반의 비선형 거동특성을 보다 깊이 있게 이해하고 해석 및 설계시 고려할 수 있을 것으로 사료된다.