• Journal of Korean Society of Environmental Engineers
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• v.37 no.11
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• pp.642-648
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• 2015

Oak wood based activated carbon was modified with surface impregnation of $Fe^{3+}$ and $Al^{3+}$ metal ions mixture for enhancements of phosphate adsorption capacity in aqueous solution. The phosphate adsorption capacity of the prepared metal impregnated carbon (MC) was about 8 times higher than that of the original activated carbon (OC). Adsorption equilibrium capacities of the phosphate increased with increasing system temperature. The adsorption equilibrium isotherm of phosphate on the prepared MC could be represented by the Langmuir equation. Thermodynamic parameters also indicated that adsorption system was spontaneous and endothermic reaction. The internal diffusion coefficient was measured to analyze the adsorption behavior and kinetic rate. To determine the internal diffusion coefficient, pore diffusion model (PDM) was employed and the result was in good agreement with experimental data.

• Journal of Korea Multimedia Society
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• v.12 no.1
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• pp.16-25
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• 2009

In the car environment that the first priority is a safety problem, the large vocabulary isolated word recognition system with POI domain is required as the optimal HMI technique. For the telematics terminal with a highly limited processing time and memory capacity, it is impossible to process more than 100,000 words in the terminal by the general speech recognition methods. Therefore, we proposed phoneme recognizer using the phonetic GMM and also PDM Levenshtein distance with multi-layer architecture for the POI recognition of telematics terminal. By the proposed methods, we obtained high performance in the telematics terminal with low speed processing and small memory capacity. we obtained the recognition rate of maximum 94.8% in indoor environment and of maximum 92.4% in the car navigation environments.

• Journal of Korea Multimedia Society
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• v.12 no.10
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• pp.1418-1426
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• 2009

There has been a lot of interest in an effective method for background subtraction in an effort to separate foreground objects from a predefined background image. Promising results on background subtraction using statistical methods have recently been reported are robust enough to operate in dynamic environments, but generally require very large computational resources and still have difficulty in obtaining clear segmentation of objects. We use a simple running-average method to model a gradually changing background, instead of using a complicated statistical technique. We employ a single global threshold vector, optimized by a genetic algorithm, instead of pixel-by-pixel thresholds. A new fitness function is defined and trained to evaluate segmentation result. The system has been implemented on a PC with a webcam, and experimental results on real images show that the new method outperforms an existing method based on a mixture of Gaussian.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.705-709
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• 2009

Based on experimental study of lycopodium dust particles' behavior, we suggest the flame propagation model through dust clouds. With dust concentration, flame velocity reaches a maximum value at $170g/m^3$ to exceed the stoichometric concentration for lycopodium-air mixture combustion and decreases slightly in the richer side of $500g/m^3$. At $47{\sim}200g/m^3$, mean velocity of particle increases in proportion to flame velocity. As the sum of burning rate and particle velocity is approximate in flame velocity, the flame propagation velocity with lycopodium dust concentration can be estimated by the calculation and it was found that behavior of particles is useful for better understanding of dust flame propagation velocity.

• Membrane Journal
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• v.13 no.4
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• pp.239-245
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• 2003

The origin of large difference of selectivity of $C_3H_6$ over $C_3H_8$ between pure gas and mixed gas through silver polymer electrolyte membranes is investigated. Firstly, the effect of feed condition on the permeance of mixture gas ($C_3H_6/C_3H^8$) and the separation performance is examined. Upon decrease of the $C_3\;H_6$ concentration, the $C_3H_6$ permeance decreased whereas the permeance of $C_3H_8$ increased, resulting in the decrease of the selectivity of $C_3H_6/C_3H_8/.$ This result is ascribed to the $C_3H_6$-induced plasticization of membranes. Experimental results were validated by means of mathematical modeling, where pressure independent permeabilities were used.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.140-152
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• 2017

This Paper is for A study of sensor fusion using Radar sensor and Vision sensor in moving object detection. Radar sensor has some problems to detect object. When the sensor moves by wind or that kind of thing, it can happen to detect wrong object like building or tress. And vision sensor is very useful for all area. And it is also used so much. but there are some weakness that is influenced easily by the light of the area, shaking of the sensor device, and weather and so on. So in this paper I want to suggest to fuse these sensor to detect object. Each sensor can fill the other's weakness, so this kind of sensor fusion makes object detection much powerful.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.460-467
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• 2006

Adsorption experiments for $H_2$, $CO_2$, CO, and their binary mixtures on zeolite 5A were performed by static volumetric method. Experimental data were obtained at temperatures of 293.15, 303.15 and 313.15 K and at pressures to 25 atm. The parameters obtained from single component adsorption isotherm. Multicomponent adsorption equilibria could be predicted and compared with experimental data. Langmuir isotherm, Langmuir-Freundlich isotherm and Dual-Site Langmuir isotherm be used to predict the experimental results for binary adsorption equilibria of $CO_2/CO$ and $H_2/CO_2$ on zeolite 5A. Dual-Site Langmuir isotherm showed the best agreement with the experimental results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.2
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• pp.237-245
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• 2012

This paper describes an acoustic echo canceller with double-talk by the blind signal separation. The acoustic echo canceller is deteriorated or diverged in the double-talk period. So we use the blind signal separation to estimate the near-end speech signal and to eliminate the estimated signal from the residual signal. The blind signal separation extracts the near-end signal with dual microphones by the iterative computations using the 2nd order statistical character. Because the mixture model of blind signal separation is multi-channel in the closed reverberation environment, we used the copied coefficients of echo canceller without computing the separation coefficients. By this method, the acoustic echo canceller operates irrespective of double-talking. We verified performances of the proposed acoustic echo canceller by simulations. The results show that the acoustic echo canceller with this algorithm detects the double-talk periods thoroughly, and then operates stably in the normal state without the divergence of coefficients after ending the double-talking. And it shows the ERLE of averagely 20dB higher than the normal LMS algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8C
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• pp.711-720
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• 2012

In this paper, we introduce the implementation of driver fatigue monitering system and its result. Input video device is selected commercially available web-cam camera. Haar transform is used to face detection and adopted illumination normalization is used for arbitrary illumination conditions. Facial image through illumination normalization is extracted using Haar face features easily. Eye candidate area through illumination normalization can be reduced by anthropometric measurement and eye detection is performed by PCA and Circle Mask mixture model. This methods achieve robust eye detection on arbitrary illumination changing conditions. Drowsiness state is determined by the level on illumination normalize eye images by a simple calculation. Our system alarms and operates seatbelt on vibration through controller area network(CAN) when the driver's doze level is detected. Our algorithm is implemented with low computation complexity and high recognition rate. We achieve 97% of correct detection rate through in-car environment experiments.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.315-325
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• 2019

The purpose of this study is to design and construct a data mart that anyone can easily analyze subway OD movement patterns. Subway OD data of the year 2017 was downloaded from the Seoul Open Data Plaza and used as the source data. A multidimensional model was designed, and Gaussian mixed cluster analysis and visualization analysis using Tableau were performed. Interestingly, movement between suburban and Seoul accounts for 23% of the total traffic. The passengers of Suwon Station move to the suburbs much more than Seoul, while Pangyo Station mostly moves to Seoul. As a result of Gaussian mixed cluster, eight clusters of OD segments were found, and the characteristics of each cluster were characterized by segment distance and passenger size.