• Journal of Korea Multimedia Society
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• v.20 no.8
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• pp.1387-1394
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• 2017

As rate in an elderly population and expanding their range of activity rapidly increase, the demographics of the elderly population on a use of transportation also rise. Elderly pedestrians often find it difficult to react promptly to the traffic accidents as they are less perceptive of the dangers present under the situation. More than half of the elderly traffic accidents are elderly pedestrian accidents in road. Therefore, we design and implement smart safety hat for safety of elderly pedestrian. The smart safety hat binds stripe-shaped LED around a hat in order for a driver to perceive pedestrian easy and quickly. Features of smart safety hat include controlling the number of LEDs by using a light sensor and warning through vibration using a sound sensor. Also, we used Bluetooth to communicate with the smartphone to enable user customization of the light and numbers of LEDs.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.311-314
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• 2003

In radar tracking, since the sensor measures range, azimuth and elevation angle of a target, the measurement equation is nonlinear and the extended Kalman filter (EKF) is applied to nonlinear estimation. The conventional EKF has been widely used as a nonlinear filter for radar tracking, but the considerably large measurement error due to the linearization of nonlinear function in highly nonlinear situations may deteriorate the performance of the EKF. To solve this problem, a fuzzy-model-based Kalman filter (FMBKF) is proposed for radar tracking. The FMBKP uses a local model approximation based on a TS fuzzy model instead of a Jacobian matrix to linearize nonlinear measurement equation. The hybrid GA and RLS method is used to identify the premise and the consequent parameters and the rule numbers of this TS fuzzy model. In two-dimensional radar tracking problem, the proposed method is compared with the conventional EKF.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.2
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• pp.211-216
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• 2013

For diffusion limited cluster agglomerates the ratio of the mobility radius to the radius of gyration $R_m/R_g$ vs. N and the ratio of the mobility radius to the radius of primary particle $R_m$/a are determined using experimental data obtained with DMA-APM and tandem DMA over a range of Knudsen numbers extending into the transition region where there is a lack of data. It was found that in slip regime with the number of primary particles between 100 and 400, datapoints are found to be between the two asymptotic lines for the continuum and free molecular regimes as those datapoints are plotted in both $R_m/R_g$ vs. N and $R_m$/a vs. N.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8B
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• pp.657-666
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• 2008

The intersection collision avoidance service among various telematics application services is regarded as one of the most critical services with regard to safety. In such safety applications, real-time, correct transmission of service is required. In this paper, we study on efficient infrastructure architecture for intersection collision avoidance using a cooperative mechanism between vehicles and wireless infrastructure. In particular, we propose an infrastructure, called CISN (Cooperative Infrastructure associated with Sensor Networks), in which proper numbers of sensor nodes are deployed on each road, surrounding the intersection. In the proposed architecture, overall service performance is influenced by various parameters consisting of the infrastructure, such as the number of deployed sensor nodes, radio range and broadcast interval of base station, and so on. In order to test the feasibility of the CISN model in advance, and to evaluate the correctness and real-time transmission ability, an intersection sensor deployment simulator is developed. Through various simulations on several environments, we identify optimal points of some critical parameters to build the most desirable CISN.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.8
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• pp.1294-1302
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• 1990

In this paper, optical implementation of single layer perceptron to discriminate the even and odd numbers using commericla LCTV spatial light modulator is described. In order to overcome the low dynamic range of gray levels of LCTV, nonlinear quantized perceptron model is introduced, which is analyzed to have faster convergent time with small gray levels through the computer simulation. And the analog weights containing positive and negative values of single layer perceptron is represented by using the polarization-based encoding method. Finally, optical implementation of the nonlinear quantized perceptron learning model based on polarization property of the commercial LCTV is proposed and some experimental results are given.

• Journal of The Korean Astronomical Society
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• v.29 no.1
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• pp.53-62
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• 1996

31 white dwarfs in 10 open clusters are examined, and their maximum mass and the upper mass limit of their progenitors are obtained as $1.22\pm0.02M_{\bigodot}\;and\;7.2\pm0.4M_{\bigodot}$ respectively, suggesting that the upper mass limit of white dwarfs is less than 8M_{\bigodot}$ The final mass of white dwarfs shows no clear correlation with the initial mass of their progenitors, and it is found that a deficient gap of initial mass exists between $\~4\;and\;~5.2M_{\bigodot}$. This gap seems to correspond to the mass range for carbon detonation or deflagration. The total expected numbers of white dwarfs are $11\~22$ in Hyades with 7 known white dwarfs and 17 in Praesepe with 8 known white dwarfs. These known white dwrfs are all younger than the others in both clusters. But one known white dwarf in Pleiades is older one among $2\~3$ expected white dwarfs.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.10a
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• pp.63-66
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• 2004

The SGA(stochastic gradient ascent) algorithm is one of the most important tools in the area of reinforcement learning, and has been applied to a wide range of practical problems. In particular, this learning method was successfully applied by Kimura et a1. [1] to the control of a simple creeping robot which has finite number of control input choices. In this paper, we considered the application of the SGA algorithm to Kimura's robot control problem for the case that the control input is not confined to a finite set but can be chosen from a infinite subset of the real numbers. We also developed a MATLAB-based robot animation program, which showed the effectiveness of the training algorithms vividly.

• Journal of Ocean Engineering and Technology
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• v.16 no.4
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• pp.1-6
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• 2002

Experimental investigation of drag reduction by adding a polymer additive(polyacrylamid, N-401P) into water is carried out in a Circular Water Channel. The effect of viscosity, surface roughness and degradation as a function of running time is also measured with varying the concentration of polymer additives(20ppm,100ppm) and Reynolds numbers. Near and far wakes past a circular cylinder are observed by LDV. Drag forces are measured with a strain-gaged device. The experimental results show that around 5%-30% of drag reduction with the polymer solution are observed. The larger effects of drag reduction can be found at low range of Reynolds number, more roughened surface cylinder. The effect of polymer solution for near wakes is larger than for far wakes.

• Journal of the Korean Society of Visualization
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• v.3 no.1
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• pp.90-96
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• 2005

Most of the previous studies on natural convection were based on the numerical analysis, and some experimental studies considered the classic case of thermal convection. In this study, an adiabatic square body was located at the center of an enclosure between the bottom hot and top cold walls. And the measurement of the detailed temperature fields was conducted by the method of two-color Laser Induced Fluorescence using a Nd:Yag laser. As a result, heat transfer characteristics of natural convection with an adiabatic body was estimated as a function of time over a range of Rayleigh numbers.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.61-62
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• 2006

The suppression of fluid force acting on a square prism near plane wall was studied by attaching fences on the comers of the prism. The height of the fence was 10% of the square width and the range of Reynolds number considered was $Re=2.0{\times}10^4$. The experimental parameters were the attaching position and numbers of fences, the space ratios $G/B(G/B=0.1{\sim}1.2)$ between prism and plane wall. The average drag coefficients were increased and the average hit coefficients were decreased and increased with the space ratios foulard plane wall. The drag of the prism was reduced average 7.6% with the space ratios by attaching the normal fence at the rear and upper comer and the horizontal normal fence at the rear and lower corner on the prism.