• 대한전기학회논문지
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• 제38권9호
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• pp.701-709
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• 1989

The time-averaged behavior of the three-phase Inductor-Converter Bridge (ICB) circuit has been analyzed by using the state-space averaging method. Especially, a second order approximation in the matrix expansion makes the analysis possible. The results are in a closed form which is quite different from the conventional solution obtained by using the Fourier Series. Therefore, the computational difficulties in evaluating the infinite Fourier series can be avoided and the results derived in this paper are available expecially in real time control. By comparing with the Fourier result, it has been verified that the analysis by means of the state-space averaging method is more accurate and simple. The digital simulation and the equivalent experiments have also been carried out to confirm the theoretical results.

• KEPCO Journal on Electric Power and Energy
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• 제7권2호
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• pp.255-261
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• 2021

This paper proposes impedance-based stability analysis of DC-DC boost converters, where a harmonic state space (HSS) modeling technique is used. At first, the HSS model of the boost converter is developed. Then, the closed-loop output impedance of the converter is derived in frequency domain using small signal modeling including frequency couplings, where harmonic transfer function (HTF) matrices of the open-loop output impedance, the duty-to-output, and the voltage controller are involved. The frequency response of the output impedance reveals a resonance frequency at low frequency region and frequency couplings at sidebands of switching frequency which agree with the simulation and experimental result.

• 한국통신학회논문지
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• 제13권6호
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• pp.510-520
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• 1988

無限誤長 상태 공간 디지틀 필터를 有限誤長 상태 공간 디지틀 필터로 실현할 때 量子化 誤差인 상태 공간 계수〔ABCD〕의 미소 변동에 기인한, 출력 오차 分散을 $\Delta$〔ABCD〕의 分散으로 正規化하였다. 즉, S=E을 統計的 感度로 정의하고 시스템 구조적 성질을 나타내는 可制御性 Gramian, 그리고 2차 모드 해석 방법을 상태 공간 디지틀 필터에 확장해서 最小 統計的 感度를 갖는 실현 구조를 합성하였으며 시뮬레이션을 통하여 최소 구조 합성의 유효성을 확인하였다.

• 환경위생공학
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• 제15권2호
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• pp.65-74
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• 2000

The purpose of this study is to develop the stochastic stream water quality model for the intake station of Chung-Ju city waterworks in the Han river system. This model was based on the theory of Box-Jenkins Multiplicative ARIMA(SARIMA) and the state space model to simulate changes of water qualities. Variable of water qualities included in the model are temperature and dissolved oxygen(DO). The models development were based on the data obtained from Jan. 1990 to Dec. 1997 and followed the typical procedures of the Box-Jenkins method including identification and estimation. The seasonality of DO and temperature data to formulate for the SARIMA model are conspicuous and the period of revolution was twelve months. Both models had seasonality of twelve months and were formulates as SARIMA {TEX}$(2,1,1)(1,1,1)_{12}${/TEX} for DO and temperature. The models were validated by testing normality and independency of the residuals. The prediction ability of SARIMA model and state space model were tested using the data collected from Jan. 1998 to Oct. 1999. There were good agreements between the model predictions and the field measurements. The performance of the SARIMA model and state space model were examined through comparisons between the historical and generated monthly dissolved oxygen series. The result reveal that the state space model lead to the improved accuracy.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.134-140
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• 2017

A well-performed core power control to track load changes is crucial in pressurized water reactor (PWR) nuclear power stations. It is challenging to keep the core power stable at the desired value within acceptable error bands for the safety demands of the PWR due to the sensitivity of nuclear reactors. In this paper, a state-space model predictive control (MPC) method was applied to the control of the core power. The model for core power control was based on mathematical models of the reactor core, the MPC model, and quadratic programming (QP). The mathematical models of the reactor core were based on neutron dynamic models, thermal hydraulic models, and reactivity models. The MPC model was presented in state-space model form, and QP was introduced for optimization solution under system constraints. Simulations of the proposed state-space MPC control system in PWR were designed for control performance analysis, and the simulation results manifest the effectiveness and the good performance of the proposed control method for core power control.

• 수산해양기술연구
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• 제55권3호
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• pp.206-216
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• 2019

This study is aimed to compare stock assessment models depending on how the models fit to observed data. Process-error model, Observation-error model, and Bayesian state-space model for the Korean Western coast fisheries were applied for comparison. Analytical results show that there is the least error between the estimated CPUE and the observed CPUE with the Bayesian state-space model; consequently, results of the Bayesian state-space model are the most reliable. According to the Bayesian State-space model, potential yield of fishery resources in the West Sea of Korea is estimated to be 231,949 tons per year. However, the results show that the fishery resources of West Sea have been decreasing since 1967. In addition, the amounts of stock in 2013 are assessed to be only 36% of the stock biomass at MSY level. Therefore, policy efforts are needed to recover the fishery resources of West Sea of Korea.

• 전자공학회논문지CI
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• 제39권3호
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• pp.62-78
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• 2002

본 논문에서는 인간의 행동을 컴퓨터에게 인식시켜 가상의 공간에 존재하는 에이전트(agent)들과 상호 작용이 가능한 시스템을 구현하였다. 이 시스템은 크게 행동을 인식하는 인식 시스템과 인식 정보를 통해 미리 구성한 가상 공간에 존재하는 여러 에이전트간의 상호 작용을 하는 시스템으로 구성되어있다. 인식 시스템은 동작자의 연속적인 행동을 CCD카메라로부터 입력받아 각각의 프레임에 대해 머리와 손의 특징을 추출한다. 그리고, 추출된 정보를 연속적인 시간의 흐름에 대해 해석을 한 후, 동작을 인식한다. 상호 작용 시스템을 위해 동작자의 분신인 아바타(avatar), 자율적으로 행동하는 퍼피(puppy), 그리고 비자율적인 객체인 탁자, 문, 창문, 공과 같은 이동이 가능한 오브젝트(object)들이 존재하는 가상 공간을 구현하였다. 인식된 동작은 상호 작용 시스템을 통해 가상 공간의 아바타에게 전달이 된다. 아바타의 동작 천이는 상태 천이도를 바탕으로 이루어진다. 상태 천이도는 각각의 동작이 노드로 정의되고, 그 노드들을 종속적으로 연결한 그래프로 구성된다. 아바타는 문과 창문을 여닫고, 오브젝트를 잡거나 이동할 수 있다. 또 퍼피에게 명령을 내리거나 퍼피의 동작에 대한 응답을 할 수 있다.

• Journal of Power Electronics
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• 제13권3호
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• pp.400-408
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• 2013

This paper presents a discrete state-space controller using state feedback control and feed-forward decoupling to provide a desirable control bandwidth and control stability for dynamic voltage restorers (DVR). The paper initially discusses three typical applications of a DVR. The load-side capacitor DVR topology is preferred because of its better filtering capability. The proposed DVR controller offers almost full controllability because of the multi-feedback of state variables, including one-beat delay feedback. Feed-forward decoupling is usually employed to prevent disturbances of the load current and source voltage. Directly obtaining the feed-forward paths of the load current and source voltage in the discrete domain is a complicated process. Fortunately, the full feed-forward decoupling strategy can be easily applied to the discrete state-space controller by means of continuous transformation. Simulation and experimental results from a digital signal processor-based system are included to support theoretical analysis.

• Structural Monitoring and Maintenance
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• 제1권4호
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• pp.427-449
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• 2014

A hybrid optimization method for the identification of state-space models is presented in this study. Hybridization is succeeded by combining the advantages of deterministic and stochastic algorithms in a superior scheme that promises faster convergence rate and reliability in the search for the global optimum. The proposed hybrid algorithm is developed by replacing the original stochastic mutation operator of Evolution Strategies (ES) by the Levenberg-Marquardt (LM) quasi-Newton algorithm. This substitution results in a scheme where the entire population cloud is involved in the search for the global optimum, while single individuals are involved in the local search, undertaken by the LM method. The novel hybrid identification framework is assessed through the Monte Carlo analysis of a simulated system and an experimental case study on a shear frame structure. Comparisons to subspace identification, as well as to conventional, self-adaptive ES provide significant indication of superior performance.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2008년도 춘계학술발표대회 논문집
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• pp.166-170
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• 2008

The elder population is growing rapidly in Korea nowadays. Therefore, a demand for adaptable installation standard of residential space for the elderly is increasing with growth of the elder population. This study analyzed actual state by interviewing manager, surveying actual measurement and using draft of Elderly nursing facility which is for senile patients. As a result of the survey for size and facilities, facilities for elderly safety, accommodation per a person and room size per a person are below to standard. Therefore, establishing adaptable design standard is needed which is to make safe and fresh living environment for the elderly.