• Journal of Advanced Navigation Technology
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• v.12 no.1
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• pp.8-14
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• 2008

In this paper, I have presented a new approach which can track moving objects in unknown environments. This scheme is important in providing a computationally feasible alternative to complete enumeration of JPDA which is intractable. I have proved that given an artificial measurement and track's configuration, proposed scheme converges to a proper plot in a finite number of iterations. In this light, even if the performance is enhanced by using the relaxation, I also note that the difficulty in tuning the parameters of the relaxation scheme is critical aspect of this suggestion.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.23-30
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• 2009

Slow sand filtration (SSF) was the first engineered/mechanical filtration process used in drinking water treatment. In SSF, untreated water slowly percolate through a bed of porous sand. Biological activity within the sand bed have the strongest influence on removal efficiency of pollutants by slow sand filtration. In this study, the microbial population distributions in slow sand filters operated at the various operation conditions was evaluated. The concentrations of $10^4$ to $10^5$ CFU per g dry wt. were observed. No significant differences were seen between the number of filter-covered materials. The data indicate that the temperature has affect on population distribution. Also, the light exposure was influenced on microorganism in slow sand filtration according to the heterotropic plate counts. The role of microorganism within the sand media requires further study.

• Tribology and Lubricants
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• v.29 no.6
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• pp.392-396
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• 2013

Biodiesel fuels contain unsaturated fatty acid ester, which can easily oxidize, especially when exposed to ultraviolet light. The products formed by this oxidation give rise to sediment or gum formation. As a result, the fuel can contribute to the corrosion and plugging of the filter pump. Antioxidants have been used in an effort to stabilize biodiesels, but there is still a need for a biodiesel composition with improved oxidation stability. In general, good fuel compositions should provide synergistic combinations of a biodiesel and antioxidants. Our work involved the synthesis of antioxidants to improve the oxidative stability of biodiesel fuel.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.387-390
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• 1996

In this paper, A new PI-type reaching law for variable structure control is proposed to alleviate the chattering and improve the robustness properties in the presence of matched uncertainty. The proposed reaching law consists of a proportional term and an integral term. And the dynamics of switching function can easily be specified by using the second-order system analysis method. And also the proposed scheme has the advantages of alleviating the chattering than Gao's one and reducing the influence of uncertainties by band pass filter characteristic. The efficiency of the proposed method has been demonstrated by simulations for Dutch Roll damping in a light aircraft.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.724-728
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• 2005

This paper represents a development of a range finder sensor module for indoor 2-D mapping and modified Hough transformation for map building. A range finder sensor module has been developed by using optic PSD (Position Sensitive Detector) sensor array at a low price. While PSD sensor is cost effective and light weighting, it has switching noise and white noise. To remove these noises, we propose a heuristic filter. For line-based map building, also we proposed advanced Hough transformation and navigation algorithm. Some experiments were illustrated for the validity of the developed system.

• 전자공학회논문지 IE
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• v.48 no.4
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• pp.25-29
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• 2011

Organic electroluminesencent device have been studied because of its easy fabrication and high brightness for plate panel display instead of CRT and LED. There are some device structure for full color filter system can be applicable to the full color application if the blue light organic electroluminesencent device(OELD) is developed. In this study, We have investigated electro-luminescent (EL) characteristics of organic EL device using Alq3, PBD as emitting material. Current and luminance can be seen that express a similar relativity in voltage and could know that luminance is expressing current relativity.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1652-1655
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• 2008

A new high contrast LCD structure for TN mode TFT-LCD, of which the contrast ratio is 1.2 times hi gher than that of the conventional one, has been developed. The contrast ratio of TFT-LCD display can be improved by some modified materials, which like as polarizer, liquid crystal, color filter and light enhancement film. In order to know which condition can get the major contribution for the upgrade of the contrast ratio, we used Taguchi method and analyzed the contribution ratio for each composition and succeed to build up the formula of contrast ratio. From this study, we could achieve the highest CR value as 1200:1 of TN mod e TFT-LCD nowadays.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.154-157
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• 2003

Precision displacement of less than a few nm resolution was measured in real-time using fiber optic EFPI sensor. The novel method for real-time processing of analyzing EFPI output signal was developed and verified. Linearity in the mean values of interferometric light intensity among adjacent fringes was shown, and the sinusoidal approximation algorithm that estimates past and coming fringe values was verified through the linearity. Real-time signal processing program was developed, and the intensity signal of the EFPI sensor was transformed to the phase shift with this program. The resolution below 0.4 ~ 10 nm in the displacement range of $0 ~ 300\mu\textrm{m}$ was obtained by reducing the photodetector noise using low-pass filter and signal averaging. The nano-translation stage with a Piezo-electric actuator and the EFPI sensor system was designed and tested. This stage successfully reached to the desired destination in $15\mu\textrm{m}$ range within 1 nm accuracy.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.143-148
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• 2003

In recent years, as the optical Communication systems are developed, the demands of essential parts such as splitter, coupler, WDM, and AWG filter are grow rapidly. The fabrication process for them is not, however, automatic. On that reason, the automation is needed for the grow of productivity. The optical alignment and attach ment is the core process in fabrication. In this paper, the 6-axis rotary stage for multi-channel optical alignment system is developed and the dynamic characteristic of this system is studied.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.353-356
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• 2002

Planar laser induced fluorescence(PLIF) has been widely used to obtain two dimensional fuel distribution. Preliminary investigation was performed to measure quantitative air excess ratio distribution in an engine fueled with LPG. It is known that fluorescence signal from acetone as a fluorescent tracer is less sensitive to oxygen quenching than other dopants. Acetone was excited by KrF excimer laser (248nm) and its fluorescence image was acquired by ICCD camera with a cut-of filter to suppress Mie scattering from the laser light. For the purpose of quantifying PLIF signal, an image processing method including the correction of laser sheet beam profile was suggested. Raw images were divided by each intensity of laser energy and profile of laser sheet beam. Inhomogeneous fluorescence images scaled with the reference data, which was taken by a calibration process, were converted to air excess ratio distribution. This investigation showed instantaneous quantitative measurement of planar air excess ratio distribution for gaseous fuel.