• 한국대기환경학회지
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• 제20권6호
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• pp.739-748
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• 2004

A hybrid dust-collector combining a fabric filter with centrifugal force was developed to enhance the performance of the conventional fabric filter systems and its performances were evaluated to compare to that of the existing dust collector. The pressure drop rapidly increased with increasing the elapsed time and the face velocity in two filtration systems. But the increasing ratio of a hybrid dust-collector compare to the existing dust collector was lower. This results were confirmed from the performance such as cleaning interval, residual pressure drop and dust loading rate. The overall collection efficiency of the hybrid dust-collector was more than 99.6% and this showed a improvement of 0.6～2% than that of the existing dust collector. Especially, the fractional collection efficiency at the particle size of around 1${\mu}{\textrm}{m}$ is about 4% higher than that of the existing dust collector.

• Journal of Power Electronics
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• 제7권3호
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• pp.257-264
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• 2007

Active power filters can be cost-effective for use in practical systems with the insertion of a few passive elements in shunt or series configuration. The resulting hybrid filters can be designed to provide dominant lower order harmonic elimination and reactive power support by the passive elements so that the burden on the active filter counterpart is reduced. In this paper, the rate reduction in the shunt active filter is estimated when it is connected in parallel with suitable passive tuned harmonic filters. The active filtering system is based on an appropriate control scheme. The simulation and the experimental results of the shunt active filter, along with the estimated value of reduction in rating, show that the hybrid shunt filtering system is quite effective in compensating for the harmonics and reactive power, in addition to being cost-effective.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.271-273
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• 1995

Hybrid active filters utilize passive filters to reduce the voltage rating and hence the VA rating of the active filter converter. A novel hybrid active filter topoloty to minimize utility current harmonics at high power levels is presented in this paper. The proposed topology combines both passive and active filters to obtain the lowest converter VA rating as compared to the converter rating in the active filter and the series-active hybrid filter configurations. This is demonstrated with experimental results from a laboratory model. Simulation results showing the effect of passive filter impedance are presented.

• 한국대기환경학회지
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• 제30권3호
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• pp.261-269
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• 2014

This study focused on the performance of the newly developed hybrid filter system to capture fine particulate matter and mercury compounds in a coal-fired power plant. The hybrid filter system combining bag-filter and electrostatic precipitator had been developed to remove fine particulate matter. However, it would have a good performance to control mercury compounds as well. In Hybrid filter capture system, the total removal efficiency of total mercury compounds consisting of particulate mercury ($Hg_p$), oxidized mercury ($Hg^{2+}$), and elemental mercury ($Hg^0$) was 66.2%. The speciation of mercury compounds at inlet and outlet of Hybrid filter capture system were 1.3% and 0% of $Hg_p$, 85.2% and 68.1% of $Hg^0$, and 13.5% and 31.9% of $Hg^{2+}$, respectively. In hybrid filter capture system injected with 100% of flue-gas, the removal efficiency of total mercury was calculated to increase to 93.5%.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.434-436
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• 1992

In this paper, we propose a new multilevel nonlinear filter for simultaneous edge detection and noise suppression, which we call a order statistic-median hybrid(OMH) filler. The median-related filters cause an edge shift in the presence of an impulse near the edge. The proposed filter reduces such edge shifting while suppressing impulsive as well as nonimpulsive noise. We show that at the noisy edge point the OMH filter is substantially superior to the median filter, the $\alpha$-TM filter and the STM filter[I] in two respects: (a) the output bias error and (b) the output mean square error. Test results confirm that the OMH filter is robust in preserving sharp edges, inhibiting edge shifting, and suppressing a wide variety of noise. The structure for the OMH filter integrated circuit is also described.

• 동력기계공학회지
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• 제8권2호
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• pp.31-38
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• 2004

The main purpose of this study is to investigate the characteristics of hybrid collection system combined with centrifugal force of cyclone and filtration of bag filter in one unit system. The experiment and numerical simulation are executed for the analysis of collection efficiency and pressure drop characteristics of hybrid system in comparison with those of a general fabric bag filter with the various experimental parameters such as inlet velocity(filtration velocity), dust concentration and dust type, etc.. In present system, dust particles tangentially coming into the system body are controlled by the centrifugal force effect, and the next collection is made out by the filtration mechanism in the fabric filter media. Therefore, the effective first collection causes the decrease of dust loading on the fabric filter, and it presents quite a lower pressure drop of fabric filter than that of a general fabric filter. At the inlet velocity, $21{\sim}27m/sec$ and inlet concentration(fly ash) $300mg/m^3$, pressure drops through the filter media of hybrid system are shown lower as $10{\sim}22mmH_2O$ comparing to those($17{\sim}33mmH_2O$) of a general fabric bag filter.

• 한국ITS학회 논문지
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• 제12권4호
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• pp.76-86
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• 2013

기존의 와이파이 기반 측위 시스템에서 주로 사용되는 칼만필터와 파티클 필터는 실내공간의 구조적 특성을 반영하지 못해 정확도가 낮고, 계산 부하 또한 높기 때문에 휴대기기를 이용한 실내 측위에 적용하는데 한계를 지닌다. 이러한 한계를 극복하고자 본 논문은 와이파이 기반 측위 시스템을 위한 적응형 혼합필터를 제안한다. 제안된 필터는 칼만 필터의 일반적인 적용 체계를 활용하였으며, 적은 수의 파티클을 사용한 파티클 필터의 개념 또한 추가되었다. 제안된 필터는 일반 칼만 필터와는 달리 예측 가중치를 동적으로 변화시켜 동작하며, 위치 예측을 위한 파티클을 실내공간의 경로 네트워크상에 한정하는 특징을 지닌다. 검증결과 적응형 혼합 필터는 일반 칼만 필터에 비해 높은 정확도를 보이며, 일반 파티클 필터에 비해서도 정확도 및 계산시간의 측면에서 유의할만한 성능향상을 보였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1334-1339
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• 2004

This paper proposes transformerless power conversion system consisting of a single-phase diode rectifier and a shunt hybrid filter for the electric-railway system. The hybrid filter consists of a single tuned LC filter per a phase and a low-rated NPC type multi-level inverter. Compared with conventional active filters. Transformers are not used. Also, LC filter works as not only a harmonic filter tuned at the 5th harmonic frequency but also a switching-ripple filter. The rating of the active filter can be decreased by using a NPC type multi-level inverter. The simulation results confirm the validity of the system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1427-1432
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• 2004

This paper proposes transformerless power conversion system consisting of a single-phase diode rectifier and a shunt hybrid filter for the electric-railway system. The hybrid filter consists of a single tuned LC filter per a phase and a low-rated NPC type multi-level inverter. Compared with conventional active filters. Transformers are not used. Also, LC filter works as not only a harmonic filter tuned at the 5th harmonic frequency but also a switching-ripple filter. The rating of the active filter can be decreased by using a NPC type multi-level inverter. The simulation results confirm the validity of the system

• Smart Structures and Systems
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• 제14권6호
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• pp.1105-1129
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• 2014

The unscented Kalman filter (UKF) has been developed for nonlinear model parametric identification, and it assumes that the model parameters are symmetrically distributed about their mean values without any constrains. However, the parameters in many applications are confined within certain ranges to make sense physically. In this paper, a constrained unscented Kalman filter (CUKF) algorithm is proposed to improve accuracy of numerical substructure modeling in hybrid testing. During hybrid testing, the numerical models of numerical substructures which are assumed identical to the physical substructures are updated online with the CUKF approach based on the measurement data from physical substructures. The CUKF method adopts sigma points (i.e., sample points) projecting strategy, with which the positions and weights of sigma points violating constraints are modified. The effectiveness of the proposed hybrid testing method is verified by pure numerical simulation and real-time as well as slower hybrid tests with nonlinear specimens. The results show that the new method has better accuracy compared to conventional hybrid testing with fixed numerical model and hybrid testing based on model updating with UKF.