• 디지털산업정보학회논문지
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• 제18권3호
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• pp.1-7
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• 2022

In this study, inaccurate RSSI values of beacons are corrected using extended Kalman filter. For the experiment, the beacon was manufactured using Arduino Uno board and HM-10 Bluetooth module. RSSI values according to the distance between beacon and the viewer were measured at intervals of 1m, 1.5m, 2m, 2.5m, 3m, 3.5m, 4m, 4.5m, and 5m. To remove the irregular signal pattern of the beacon, the extended Kalman filter was applied to obtain the average and standard deviation of the actual distance and the measured distance, and it was confirmed that more than 76.6% of the irregular signal pattern was removed after using the extended Kalman filter.In addition, through the smartphone app, it was confirmed that the distance accuracy between the beacon and the measurer was less than the actual distance and the measured distance within 2m, and the standard deviation was small.

• 설비공학논문집
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• 제25권4호
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• pp.194-200
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• 2013

In this study, an exhaust filter unit for removing bad smells is designed and manufactured to understand the characteristics, damages, and effects on humans and animals of bad smell substances in laboratory animal breeding facilities. Using the exhaust filter unit, a deodorization performance test using ammonia gas, as a typical bad smell in an animal breeding room, was carried out for three types of activated and impregnated charcoal filters. The experimental results showed that the pressure loss of the HEPA and carbon filter was increased with flow rate and that the average deodorization performance for the case where an impregnated carbon filter was installed was a maximum value of between 93 and 96%, with various fractional flow rates ranging from 1,500 to $3,500m^3/h$ in a laboratory animal breeding room. The experimental results will also be used for the design and manufacture of a practical and efficient exhaust filter unit to cope with bad smell problems in animal breeding facilities.

• 상하수도학회지
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• 제23권1호
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• pp.121-128
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• 2009

Objectives of this study were to investigate influencing factors of detention time, particle size distribution, and filter medium characteristics for waterworks sludge dewatering. The stepped pressure filtration was carried out with lab scale apparatus and the filter press pilot test for dewatering was conducted at the water treatment plant. Effects of filter medium and polymer dose were examined through observing water content and dewatering velocity and cyclic dewatering rate with filter press pilot test. Relationships among detention time, particle size distribution and filtration resistance were analyzed. Prolongation of sludge detention time was found to cause blinding phenomenon in cake and filter medium and to decrease dewatering process efficiency. The average specific resistance increased according to detention time. In pilot test of dewatering for thickened sludge with Nylon Multi-NY840D and Nylon Mono-100% filter media, dewatering velocities were 0.92 and $0.93kg\;DS/m^2{\cdot}hr$ according to 0.1% polymer dose of dried solids weight base. And cyclic dewatering rates were 2.45 and $2.50kg\;DS/m^2{\cdot}cycle$ cycle for the Nylon Multi-NY840D and Nylon Mono-100% media. Dewatering velocity of polymer dosed sludge was observed to be higher than that of non-polymer sludge.

• 한국정보통신학회논문지
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• 제18권4호
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• pp.986-991
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• 2014

모바일 헬스케어와 원격진료에서 사용되는 광용적 맥파(PPG) 신호는 환자로부터 발생되는 여러 가지의 동잡음을 포함하고 있다. 이러한 동잡음을 제거하기위해 이동평균필터, 적응필터, 가속도 센서 등을 이용한 기법이 제시되었으나, 아직까지도 그 성능이 만족 스럽지 못하다. 따라서 본 연구에서는 이러한 동잡음 문제를 해결하기 위해 칼만필터와 적응필터를 이용한 새로운 동잡음 제거 기법을 제안하고 그 성능을 평가하기위해 다양한 동잡음을 사용하였다. 이 실험의 결과에서 제안된 방법의 신호대 잡음비는 이동 평균 필터 보다 4.8배인 우수한 성능을 보였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.911-913
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• 2013

사용자의 행동 추론에서는 수신된 센서 데이터의 신뢰성이 중요하다. 하지만 외 내부 환경, 온도, 진동 등에 따라 센서의 측정값이 달라진다. 이러한 잡음 환경은 센서로부터 수집되는 정보의 신뢰성에 영향을 준다. 때문에 잡음을 감소시키고 사용자의 행동을 추론하는 디지털 필터와 추론 알고리즘이 요구된다. 본 연구는 사용자 행동의 잡음 제거, 왜곡 방지로 칼만 필터와 지수 가중이동 평균 필터의 비교실험을 하였다. 또한 본 제안된 확장가중 이중필터 법과 비교하였다. 결과적으로 제안된 필터가 다른 필터에 비해 잡음 환경에 견고하였다.

• 한국컴퓨터정보학회논문지
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• 제4권2호
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• pp.120-134
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• 1999

영상 처리는 영상 획득, 전처리, 영역화, 인식의 단계를 거치게 되며, 영상은 데이터 전송과정이나 테이터의 획득과정 및 데이터의 처리과정에서 잡음에 의해 쉽게 훼손된다. 이러한 과정에서 발생되는 잡음으로 대표적인 것이 임펄스 잡음과 가우시안 잡음이다. 이러한 잡음을 제거하는 기존의 필터링 방법들 중에는 공간적인 처리 기법으로 평균필터, 메디안필터, 가중필터, cheikh 필터 그리고 이규철 필터 등이 있었지만 많은 연구들이 임펄스 잡음의 제거에 치우쳐져 있고, 비교적 가우시안 잡음의 제거에 대한 연구는 미비한 편이다. 본 논문에서는 가우시안 잡음의 제거를 위해서는 부분 집합의 평균 정보와 메디안 방법을 이용한 부분 집합 평균 메디안 필터를 제시한다. 이 방법에서도 고려되는 윈도우의 크기는 3$^{*}$ 3를 적용하였다. 먼저 해당 윈도우내 픽셀을 중심픽셀 및 근접한 픽셀을 포함하여 4픽셀로 구성되는 4개의 부분집합으로 구성한 후, 각각의 평균을 구하고 여기서 구해진 4 부분집합의 평균값에 대한 정보와 중심 픽셀의 값과 함께 정렬을 하여 메디안 값을 구하는 방법이다. 이를 통해 가우시안을 기존의 방법보다 더 효율적으로 제거 할 수 있었다. 제시된 알고리즘은 Sun Ultra 2에서 ANSI C 언어를 사용하여 테스트되었으며, 기존의 필터 방법과의 제시된 필터 방법간의 PSNR, MSE, RMSE 값의 비교를 통해 비교 영상과 잡음들에서의 필터 성능과 효과를 제시하였다.

• 한국물환경학회지
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• 제35권2호
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• pp.145-151
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• 2019

The purpose of this study was to investigate treatment characteristics of diatomite filtration, that would allow water recovery from biologically-treated effluent for reuse. Diatomite, Celpure 100, and acid clay were used as filter-aids, with a support filter manufactured from polyethylene (PE), and polypropylene (PP). This pre-coating process using diatomite filter-aids, is used in the filtration range of pressure filters, and has consistently provided high-quality separation. The results showed that variations in average removal efficiency of SS, and T-P from biologically treated effluent by the diatomite-coated PE filter, were approximately 82.2 ~ 88.9 % and 4.8 ~ 21.1 %, respectively. T-P treatment efficiency of the PP filter pre-coated with diatomite and $Celpure^{(R)}100$ at $57.64g/m^2$, was approximately $24{\pm}10%$ and $40{\pm}15%$ on average, respectively. Particle size distribution of secondary effluent varied from 0.05 to $200{\mu}m$, and $d_{50}$ value was $20.76{\mu}m$. The size distribution of particles in the diatomite filtrate ranged from 1.26 to $101.1{\mu}m$ when pre-coated with diatomite filter-aid, at a content of $57.64g/m^2$. Diatomite filter aids, i.e., the particles that form the pre-coating layer, capture very fine particles as well as macromolecules, owing to their complex structure with numerous fine microscopic pores, and surface properties. The filtration process using diatomite and $Celpure^{(R)}100$ as filter aids, has been successfully applied, to recover water from sewage for reuse. The disadvantage of the process, is that the particle size of the filter-aid is spent, because of pressurization.

• 한국항행학회논문지
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• 제27권1호
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• pp.43-49
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• 2023

객체 위치추적은 칼만필터나 루엔버거 추적기와 같은 다양한기법을 통해 연구되고 있는데, 시스템 모델이 명확하게 규정되지 않는경우와 같이 기존의 신호처리 기법을 성공적으로 적용하기 어려운 상황에서도 객체의 위치를 추적해 낼 수 있는 인공신경망을 설계하는 것이 가능하다. 본 논문에서는, 불규칙하게 운동 상태가 변화하는 객체의 위치를 지속적으로 추적하기 위해, 다양한 길이의 최대우도기법 객체위치 추정깂들을 도출한 뒤 신경망을 통해 이들을 적응적으로 가중평균하는 방법을 사용하는 '최대우도 가중평균 신경망'을 제안한다. 해당 신경망은 객체의 위치를 직접 추정하지 않고 데이터 길이가 다른 다양한 최대우도기법 추적 결과들을 가중평균하여 위치 추정을 수행한다. 우리는 제안하는 시스템의 추적성능을 칼만필터 및 최대우도기법들과 비교하여, 제안하는 기법이 물체의 움직임 특성에 잘 대처하여 우수한 성능을 나타내 줌을 보인다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2006년도 춘계공동학술대회 논문집
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• pp.92-100
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• 2006

In many common control charting situations, the statistic to be charted can be viewed as the output of a linear filter applied to the sequence of process measurement data. In recent work that has generalized this concept, the charted statistic is the output of a general linear filter in impulse response form, and the filter is designed by selecting its impulse response coefficients in order to optimize its average run length performance. In this work, we restrict attention to the class of all second-order linear filters applied to the residuals of a time series model of the process data. We present an algorithm for optimizing the design of the second-order filter that is more computationally efficient and robust than the algorithm for optimizing the general linear filter. We demonstrate that the optimal second-order filter performs almost as well as the optimal general linear filter in many situations. Both methods share a number of interesting characteristics and are tuned to detect any distinct features of the process mean shift, as it manifests itself in the residuals.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.357-357
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• 2000

In this study, we consider a multi-input multi-output styrene polymerization reactor system for which the monomer conversion and the weight average molecular weight are controlled by manipulating the jacket inlet temperature and the feed flow rate. The reactor system is identified by using a linear subspace identification method and then the output feedback model predictive controller is constructed on the basis of the identified model. Here we use the Best Linear Unbiased Estimation (BLUE) filter as a stochastic estimator instead of the Kalman filter. The BLUE filter observes the state successfully without any a priori information of initial states. In contrast to the Kalman filter, the BLUE filter eliminates the offset by observing the state of the augmented system regardless of a priori information of the initial state for an integral white noise augmented system. A BLUE filter has a finite impulse response (FIR) structure which utilizes finite measurements and inputs on the most recent time interval [i-N, i] in order to avoid long processing times.