• 정보저장시스템학회:학술대회논문집
• /
• 정보저장시스템학회 2005년도 추계학술대회 논문집
• /
• pp.26-30
• /
• 2005

Stamper surface temperature is very critical in replicating the high density optical disc substrates using injection molding as the pit or land/groove patterns on the optical disc substrate have decreased due to the rapid increase of areal density. During the filling stage, the polymer melt in the vicinity of the stamper surfaces rapidly solidifies and the solidified layer generated during polymer filling greatly deteriorates transcribability and fluidity of polymer melt. To improve transcribability and fluidity of polymer melt, stamper surface temperature should be controlled such that the growth of the solidified layer is delayed during the filling stage. In this study, the effect of heating on replication process was simulated numerically. Then, an injection mold equipped with instant active heating system was designed and constructed to raise the stamper surface temperature over the glass transition temperature during filling stage of the injection molding. Also, the closed loop controller using the Kalman filter and the linear quadratic Gaussian regulator was designed. As a result, the stamper surface temperature was controlled according to the desired reference stamper surface temperature.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2007년도 정기 학술대회 논문집
• /
• pp.639-644
• /
• 2007

The accurate peak response estimation of a seismically excited structure with frictional damping system(FDS) is very difficult since the structure with FDS shows nonlinear behavior dependent on the structural period, loading characteristics, and relative magnitude between the frictional force and the excitation load. Previous studies have estimated that by replacing a nonlinear system with an equivalent linear one or by employing the response spectrum obtained based on nonlinear time history and statistical analysis. In the case that on earthquake load is defined with probabilistic characteristics, the corresponding response of the structure with FDS has probabilistic distribution. In this study, nonlinear time history analyses were performed for the structure with FDS subjected to artificial earthquake loads generated using Kanai-Tajimi filter. An equation for the probability density function (PDF) of the displacement response is proposed by adapting the PDF of the normal distribution. Finally, coefficients of the proposed PDF is obtained by regression analysis of the statistical distribution of the time history responses. Finally, the correlation between PDFs and statistical response distribution is presented.

• 대한조선학회지
• /
• 제21권4호
• /
• pp.10-20
• /
• 1984

When the hydrodynamic coefficients of the ship maneuvering equation are estimated by captive model test, it is difficult to take account of the scale effect between model and full scale ship. This scale effect problem can be overcome by processing the sea trial data with system identification. Extended Kalman filter is used as a system identification technique for the modification of the simulation equation as well as the estimation of hydrodynamic coefficients The phenomena of simultaneous drifting of linear coefficients occur. It is confirmed that two coefficients in each pair-$(Y_v',\;Y_r'-m'u'),\;(N_v',\;N_r')$-are simultaneously drifting and all 4 coefficients are drifting together. Particularly simultaneous drifting and 2 coefficients in each pair is more significant. It is also shown that the simultaneous drifting of 4 coefficients can be reduced by choosing the input data which have the random v'/r' curve and 4 coefficients are estimated within $2{\sim}4%$ error, which may be noise level. So, it is recommended to operate the rudder randomly in sea trial or model test for the application of system identification technique.

• 한국통신학회논문지
• /
• 제21권7호
• /
• pp.1706-1715
• /
• 1996

결정 궤환 등화기는 선형 등화기에 비해 잡음을 증폭시키지 않으면서 심벌간 간섭이 심한 채널을 보상할 수 있기 때문에 최근에 많이 사용되기 있다. 본 논문에서는 에러의 궤환을 사용하여 결정 궤환 등화기의 성능을 더욱 향상시킨 새로운 결정 궤환 등화기 구조를 제안한다. 피드포워드나 피드백워드 필터로 제거되지 않은 에러 신호의 상관성을 더욱 감소시킴으로써 향상된 성능을 얻을 수 있다. 제안된 방법은 기존의 방법에 비해 적은 수의 탭을 추가적으로 필요로 하므로 하드웨어 구현을 위한 복잡도는 거의 증가하지 않는다. 이론적인 분석과 모의실험을 통해 알고리듬이 기존의 결정 궤환 등화기에 비해 효율적이며, 심벌간 간섭이 심한 채널의 경우에 더욱 향상된 성능을 가짐을 보인다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2019년도 추계학술대회
• /
• pp.70-72
• /
• 2019

For the safe and reliable operation of Lithium-ion batteries in Electric Vehicles (EVs) or Energy Storage Systems (ESSs), it is essential to have accurate information of the battery such as State of Charge (SOC). Many kinds of different techniques to estimate the SOC of the batteries have been developed so far such as the Kalman Filter. However, when it is applied to the multiple number of batteries it is difficult to maintain the accuracy of the estimation over all cells due to the difference in parameter value of each cell. Moreover the difference in the parameter of each cell may become larger as the operation time accumulates due to aging. In this paper a novel Deep Neural Network (DNN) based SOC estimation method for multi cell application is proposed. In the proposed method DNN is implemented to learn non-linear relationship of the voltage and current of the lithium-ion battery at different SOCs and different temperatures. In the training the voltage and current data of the Lithium battery at charge and discharge cycles obtained at different temperatures are used. After the comprehensive training with the data obtained with a cell resulting estimation algorithm is applied to the other cells. The experimental results show that the Mean Absolute Error (MAE) of the estimation is 0.56% at 25℃, and 3.16% at 60℃ with the proposed SOC estimation algorithm.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1996년도 춘계학술대회 논문집
• /
• pp.24-29
• /
• 1996

The seniconductor, which is precision product, requires many inspection processes. The surface conditions of the semiconductor chip effect on the functions of the semiconductors. The defects of the chip surface is crack or void. Because general inspection method requires many inspection processes, the inspection system which searches immediately and preciselythe defects of the semiconductor chip surface. We propose the inspection method by using the computer vision system. This study presents an image processing algorithm for inspecting the surface defects(crack, void)of the semiconductor test samples. The proposed image processing algorithm aims to reduce inspection time, and to analyze those experienced operator. This paper regards the chip surface as random texture, and deals with the image modeling of randon texture image for searching the surface defects. For texture modeling, we consider the relation of a pixel and neighborhood pixels as noncasul model and extract the statistical characteristics from the radom texture field by using the 2D AR model(Aut oregressive). This paper regards on image as the output of linear system, and considers the fidelity or intelligibility criteria for measuring the quality of an image or the performance of the processing techinque. This study utilizes the variance of prediction error which is computed by substituting the gary level of pixel of another texture field into the two dimensional AR(autoregressive model)model fitted to the texture field, estimate the parameter us-ing the PAA(parameter adaptation algorithm) and design the defect detection filter. Later, we next try to study the defect detection search algorithm.

• 천문학회보
• /
• 제37권2호
• /
• pp.204.2-204.2
• /
• 2012

FPC (Fine-guiding and astroPhysics Camera)는 일본 ISAS/JAXA, 유럽 ESA에서 공동 개발하는 대형적외선우주망원경 SPICA (Space Infrared Telescope for Cosmology and Astrophysics)에 탑재하기 위하여 천문연이 주도하는 한국의 컨소시움에서 개발을 추진하고 있는 정밀 근적외선 카메라이다. FPC는 과학적 목적을 위한 FPC-S와 정밀 자세결정을 위한 FPC-G로 이루어져 있으며 관측 파장 대역은 0.7-5 um이다. FPC-G는 0.05 각초의 초정밀 자세 결정을 위한 기능을 갖추고 있으며, FPC-S는 선형변화필터 LVF (Linear Variable Filter) 등을 사용하여 Pop III stars, High-redshift 영역에서의 별탄생 및 은하 진화 과정에 대한 연구를 수행할 수 있다. FPC는 상대적으로 시스템 자원을 덜 소모하기 때문에, 다른 중 적외선 원적외선 기기와 동시 관측이 가능하다. 다른 기기들과의 잘 짜여진 협력 관측을 통하여, FPC의 활용도를 높일 계획이다.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 1999년도 유체기계 연구개발 발표회 논문집
• /
• pp.81-89
• /
• 1999

The major source of noise in the process of transporting liquids is related to the cavitation phenomenon. The control valve noise is mostly dominated by bubble dynamics under cavitating conditions. In this investigation, an orifice configuration is set-up to correlate its flow-field and acoustic signatures with those from a control valve device. The performance and noise characteristics form the orifice configuration in anechoic surroundings were measured to reveal the noise sources depending on pressure differences across the orifice configuration. The sound powers from the orifice configuration are effectively normalized using proposed scaling parameters. Flow-excited dynamic systems for which there is no strong coupling between the flow and the system response can be described using a linear source-filter model. On this assumption, the normalized sound powers can be decomposed of noise source function and a response function. To find noise sources, pressure spectra measured over a range of pressure differences are transformed into the product of two non-dimensional frequency function : $P_{ss}(He,f_{ca},x/D) = F(f_{ca})\;G(He,x/D)$. This scheme of finding noise sources is shown to be applicable to the cavitation noise from the control valve effectively Two kinds of cavitating modes based on our experimental data are found and discussed.

• 조명전기설비학회논문지
• /
• 제13권4호
• /
• pp.47-55
• /
• 1999

본 논문에서는 반복적 방법을 이용하여 열교환기 시스템의 온도제어를 위한 제어기를 구성하였다. 쌍선형 시스템으로 표현되는 열교환기 시스템에 대하여 최적이론을 적용하기 위하여 반복적 방법이 가능하도록 시스템을 구성하였으며, 상태궤환 제어기의 설계를 위하여 이 시스템의 상태인 증기온도를 추정하기 위한 확장 칼만 필터를 제시하였다. 또한 설계된 제어기를 화력발전소의 과열기 시스템의 온도제어에 적용하였고, 컴퓨터 시뮬레이션을 통하여 추정값이 외부입력의 변동 하에서 상태값에 적절하게 추종됨을 확인하였으며, 출구의 증기온도가 이러한 외부입력의 변동 하에서 주어진 목표치고 추종함을 보였다.

• 한국통신학회논문지
• /
• 제41권9호
• /
• pp.1041-1043
• /
• 2016

이 논문은 새로운 블라인드 부분 간격 등화기를 제안한다. 기존의 선형 계획법을 이용한 등화기는 등화기 필터 탭의 자유도를 강제로 줄였기 때문에 성능이 저하된다. 제안 방법은 특이값 분해를 통해 신호 공간을 구해 표본을 최대한 사용하여 등화기 성능을 향상시킨다. 제안 방법은 핵 노름을 이용한 등화기와 성능은 비슷하면서도, 기존 선형 계획법을 이용한 등화기와 비슷한 낮은 복잡도를 갖는다.