• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1083-1085
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• 1996

Controlling chaos is a new concept, which transform chaotic signal to fixed points, or low periodic orbits. In this paper we propose state feedback method in order to control chaotic signal in canonical Chua's circuit Canonical Chua's circuit is a simple electronic circuit consists of two linear resistors, a linear inductor, two linear capacitors, and only one nonlinear element so called Chua's diode. This nonlinear element supplies power to the circuit and drives the chaotic oscillations. Proposed control method is successful to control chaotic signal in canonical Chua's circuit Result shows that chaotic trajectory change rapidly its orbit to stable fixed points, 1 periodic orbit, or 2 periodic orbit when control signal applies.

• Journal of Information Processing Systems
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• 제7권4호
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• pp.653-678
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• 2011

WiMAX is intended for fourth generation wireless mobile communications where a group of users are provided with a connection and a fixed length queue. In present literature traffic of such network is analyzed based on the generator matrix of the Markov Arrival Process (MAP). In this paper a simple analytical technique of the two dimensional Markov chain is used to obtain the trajectory of the congestion of the network as a function of a traffic parameter. Finally, a two state phase dependent arrival process is considered to evaluate probability states. The entire analysis is kept independent of modulation and coding schemes.

• Journal of Hydrospace Technology
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• 제1권1호
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• pp.66-74
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• 1995

Unknown parameters can be determined by system identification techniques. Extended Kalman filter method was introduced as a real time estimator of hydrodynamic derivatives but it has the problem named the coefficient drift. In this study, 2nd order filter estimates hydrodynamic derivatives in Abkowitz model In order to reduce the coefficient drift, parallel processing is used. The measured state and ship trajectory are compared with the estimated values. Parallel processing of 2nd order filter gives very similar results to parallel processing of extended Kalman filter. Parallel processing cannot not remove the coefficient drift perfectly, but it reduces the estimation error.

• East Asian Economic Review
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• 제24권4호
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• pp.469-495
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• 2020

This paper overviews different exit strategies for the U.S. from the debt-overhang, and analyses their implications for emerging markets and global stability. These strategies are discussed in the context of the debates about secular-stagnation versus debt-overhang, the fiscal theory of the price level, the size of fiscal multipliers, prospects for a multipolar currency system, and historical case studies. We conclude that the reallocation of U.S. fiscal efforts towards infrastructure investment aiming at boosting growth, followed by a gradual tax increase, aiming at reaching a modest primary fiscal surplus over time are akin to an upfront investment in greater long-term global stability. Such a trajectory may solidify the viability and credibility of the U.S. dollar as a global anchor, thereby stabilizing Emerging Markets economies and global growth.

• International Journal of Aerospace System Engineering
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• 제7권2호
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• pp.6-12
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• 2020

The precise prediction of future position of satellite depends on the accurate determination of orbit, which is also helpful in performing orbit maneuvers and trajectory correction maneuvers. For estimating the orbit of satellite many methods are being used. Some of the conventional methods are based on (i) Differential Correction (DC) (ii) Extended Kalman Filter (EKF). In this paper, Differential Evolution (DE) is used to determine the orbit. Orbit Determination using DC and EKF requires some initial guess of the state vector to initiate the algorithm, whereas DE does not require an initial guess since a wide range of bounds for the design unknown variables (orbital elements) is sufficient. This technique is uniformly valid for all orbits viz. circular, elliptic or hyperbolic. Simulated observations have been used to demonstrate the performance of the method. The observations are generated by including random noise. The simulation model that generates the observations includes the perturbation due to non-spherical earth up to second zonal harmonic term.

• 한국정밀공학회지
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• 제12권6호
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• pp.145-151
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• 1995

The first-order Taylor series expansion can be evaluated analytically from the formulated symbolic nonlinear dynamic equations. A closed-form linear dynamic euation is derived about a nominal trajectory. The state space representation of the linearized dynamics can be derived easily from the closed-form linear dynamic equations. But manual symbolic expansion of dynamic equations and linearization is tedious, time-consuming and error-prone. So it is desirable to manipulate the procedures using a computer. In this paper, the analytic linearization is performed using the symbolic language MATHEMATICA. Two examples are given to illustrate the approach anbd to compare nonlinear model with linear model.

• 한국대기환경학회지
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• 제22권2호
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• pp.179-189
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• 2006

Ambient gas phase mercury concentrations including elemental mercury ($Hg^0$) were measured at the Potsdam, Stockton, and Sterling sites in NY from 2000 to 2003. Also, concentrations of ambient reactive gaseous mercury (RGM; $Hg^{2+}$) were measured at the Potsdam site during one year. The contribution of RGM($4.2{\pm}6.4pg/m^3$) was about $0.2{\sim}3%$ of the total gas phase mercury concentration measured (TGM: $1.84{\pm}1.24,\;1.83{\pm}0.32,\;3.02{\pm}2.14ng/m^3$ in Potsdam. Stockton, and Sterling, respectively) at the receptor sites. Potential Source Contribution Function (PSCF), a hybrid receptor modeling incorporating backward trajectories was performed to identify source areas of TGM. Using PSCF, southern New York, North Carolina, and eastern Massachusetts were identified as important source areas in the United States, while the copper smelters and waste incinerators located in eastern Quebec and Ontario were determined to be significant sources in Canada. The Atlantic Ocean was suggested to be a possible mercury source. PSCF incorporating back-dispersion and deposition was applied for RGM , as well as PSCF based on 2-days back-trajectories. Two different approaches yielded considerably different results, primarily due to the consideration of dispersion rather than deposition. Using back-trajectory based PSCF, eastern Ohio, southern New York, and southern Pennsylvania where large coal -fired power plants area located were identified as the large sources in US. Metallurgical industry located in eastern Quebec was resolved as well. From the result of back-dispersion and deposition based PSCF, Pennsylvania, mining facilities around Lake Superior, Toronto, Boston, MA, Quebec, and coal power plants in NY were identified to be the significant source areas for Potsdam site.

• 한국정보통신학회논문지
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• 제15권8호
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• pp.1727-1734
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• 2011

본 논문에서는 잉크젯 프린터의 고품질 인쇄 및 인쇄 속도 향상을 위하여 헤드 노즐로부터 분사된 잉크 액적의 위치 제어 정밀도를 향상할 수 있는 방법을 제안한다. 샤프트를 따라 이동하고 있는 캐리지에 탑재된 잉크젯 프린터 헤드의 노즐로부터 분사 신호에 동기되어 분사된 액적의 운동 방정식을 수립하고 이로부터 액적이 용지에 도달하는 궤적을 모델링하여 탄착지점을 예측함으로써 분사 액적을 원하는 지점에 정확하게 탄착시키도록 액적 분사 신호의 타이밍을 제어하는 방법을 제안한다. 캐리지의 위치 신호와의 단순 동기에 기반을 둔 기존의 분사 제어 방법에 비해 본 논문에서 제안하는 방법은 이동하는 캐리지의 속도를 고려하여 분사 타이밍을 보상하므로 캐리지의 속도 변동에 대해서도 보다 정확한 위치 제어가 가능하여 고품질 인쇄를 구현할 수 있을 뿐만 아니라 방향 전환을 위한 가감속 구간에서도 프린팅을 가능하게 하므로 동일한 인쇄 영역에 대해서 캐리지의 이동 경로가 짧아져 인쇄 속도를 향상시킬 수 있다.

• 한국항공우주학회지
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• 제30권7호
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• pp.51-60
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• 2002

통계학적 해석인 몬테-칼로 모의실험은 대기권 재진입 분산의 결과인 낙하예정지역뿐만 아니라 상태변수들의 최종조건들을 조사하는데도 사용된다. 본 논문에서 재진입 분산은 위도, 경도, 고도, 뱅크각, 비행경로각, 기수 오차, 그리고 항속거리로 생성되는 $7\times7$ 공분산 행렬로 한정된다. 감속을 목표로 하는 대기권 재진입시 이것들에 영향을 미치는 오차 원인들은 대기밀도, 온도, 초기오차, 바람, 그리고 항력계수의 추정오차 등에 관련된 불확실성들로서 이들 오차의 $3{\sigma}_n$와 공칭 비행궤적을 사용해서 상태변수의 공분산 행렬은 궤적 오차 해석을 수행함으로 결정될 수 있다. 재진입에 대한 몬테-칼로법의 적용에 있어서 주요 고려할 점은 교란궤적, 뱅크역전, 그리고 이 제적들 각각에 대한 최종 낙하지점의 결정이다. 본 논문은 불확실성에 대한 결과를 공력계수와 뱅크역전의 관점에서 해석한다.

• 대한전자공학회논문지SP
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• 제49권1호
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• pp.31-40
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• 2012

본 논문은 시각적 랜드마크를 제안하고, 이를 이용한 주차 보조 시스템을 보인다. 시각적 랜드마크는 주차 박스에 해당하는 특징으로 주차장의 환경을 고려하여 선택한다. 주차장은 두드러진 특징이 없는 단순한 모양이 반복되는 패턴을 가지는 환경으로, 기존 랜드마크는 주차장 환경에 사용하기 적당하지 못하다. 본 논문에서는 이런 주차장 환경에 맞는 랜드마크를 제안한다. 우리는 제안한 랜드마크를 사용하여 자동차의 위치를 추정하고, 현재 자동차 상태에 따른 자동차의 궤적을 예측한다. 시스템의 입력은 자동차에 장착된 카메라 한 대에서 촬영한 영상이다. 이 영상으로 자동차의 위치를 추정하고, 현재 바퀴 상태를 사용해 자동차가 주차장의 어디로 움직일 지를 보여주는 방식으로 운전자를 보조한다. 실험을 통해 제안한 시각적 랜드마크의 성능과 이를 사용한 주차 보조 시스템의 성능을 보였다.