• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1790-1795
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• 2013

The current velocity and turbulence information in each range cell can be obtained from the first and second Doppler spectrum moment estimates. However, the very widely used correlation method often called as the pulse-pair method has the inherent restrictions under the highly turbulent conditions since it does not satisfy the assumptions that the return Doppler spectrum should be symmetric and have a single peak value. Therefore, in this paper, the quality of pulse-pair estimates were compared with that of FFT estimates for problem analysis using various shapes of simulated Doppler spectra. It can be known that the pulse-pair method often yields meaningless results if the received signals are severely biased or multi-peak Doppler spectra in the Doppler frequency domain.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.563-565
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• 2010

LED is low power and pro-environment semiconductor element. That can be used not only as the lighting function but also for Visible Light Communication(VLC). The VLC is the communication technology that can send data by blinking a fluorescent or LED using visible spectrum. That velocity of blinking can not be usually recognized by eyesight. Visible Light Communication using LED can be used in many fields. In the field of ITS(Intelligent Transportation System), Under construction on the road, Emitting traffic signs can be applied to transfer the vehicle information. In this paper, Emitting traffic signs in addition to the VLC give information about road condition, safety distance and the lane change. We design Communication protocol to provide safety service and verify protocol by experiment.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.11
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• pp.137-146
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• 2015

In this paper, we propose a pothole detection method using various features of intensity and motion. Segmentation, decision steps of pothole detection are processed according to the values which are derived from feature characteristics. For segmentation using intensity, we use a binarization method using histogram to separate pothole region from background. For segmentation using motion, we filter using high pass filter and get standard deviation value. This value is divided by regression value according to camera environment such as photographing angle, height, velocity, etc. We get binary image by histogram based binarization. For decision, candidate regions are decided whether pothole or not using comparison of candidate and background's features. Experimental results show that our proposed pothole detection method has better results than existing methods and good performance in discrimination between pothole and similar patterns.

• Korean Journal of Remote Sensing
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• v.37 no.5_3
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• pp.1349-1359
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• 2021

Acquisition of precise position and velocity information of GNSS-INS (Global Navigation Satellite System; Inertial Navigation System) sensors in obtaining SAR SLC (Single Look Complex) images from raw data using BPA (Backprojection Algorithm) was regarded decisive. Several studies on BPA were accompanied by Kalman Filter for sensor noise oppression, but often implemented once where insufficient information was given to determine whether the filtering was effectively applied. Multiple operation of Kalman Filter on GNSS-INS sensor was presented in order to assess the effective order of sensor noise calibration. FMCW (Frequency Modulated Continuous Wave)-SAR raw data was collected from twice airborne experiments whose GNSS-INS information was practically and repeatedly filtered via Kalman Filter. It was driven that the FMCW-SAR raw data with diverse path information could derive different order of Kalman Filter with optimum operation of BPA image restoration.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.187-197
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• 2008

While driving a highway, A driver gets lots of information through geometrical structure, traffic situation, signs on the road. He gets most of the information by visual sense. Acceleration or deceleration and driving direction depend on sight distance. Therefore, it's essential to secure a driver's sight distance for a safe drive. However, design guides of geometrical structure and sight distance suggest respective standards of horizontal and vertical alignment. They do not indicate quantitative standard of combined alignment. Currently, element separated on a two-dimensional projected plane are available, but they do not guarantee safe and pleasant design. I will use the existent model analysing three-dimensional sight distance through mathematical calculation and sort a variety of geometrical structure element and type. In these researches, we will look at how much three-dimensional sight distance is overestimated or underestimated compared to two-dimensional. I will develop a program which predicts traffic velocity on the curvature of two-lane provincial road. stopped sight distance and three-dimensional sight distance will be compared at a predicted drive velocity. I will suggest the way to evaluate road consistency.

• Applied Biological Chemistry
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• v.4
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• pp.29-32
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• 1963

The Gibberellin is applied to partial fruit trees, vegetables and flowers, but there is only a few information on the components of the effect of Gibberellin on these higher plants. There is no any information on the effect of Gibberellin, Urea and Sucrose mixed liquid on the plant components. So this mixed liquid and gibberellin spraied to the soybean sprout and observed growth velocity variety of some nutrients. Growth velocity, weight, Amino acid contents and fat contents of mixed plot and gibberellin plot are almost same. Mixed liquid plot's sugars and crude proteins contents in a little much than gibberellin plot, but mixed liquid plot's Ascorbic acid contents is a little less than gibberellin plot.

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.2
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• pp.25-33
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• 2002

We were trying to understand indirectly the range of the discharge from the Nakdong with the dispersion of suspended solid(SS) related to the amount of discharge from river in this study. The range of dispersion of SS from the Nakdong was estimated using satellite remote sensing and numerical modeling. The stream field with two dimensional and numerical model using the condition of integrated depth was calculated. According to the results, the streamline flowed from Busan to the Jinhae Bay and Geojae Island. at the flood. The situation at the ebb was totally changed. The streamline flowed out Busan from the Bay. The velocity in offshore was faster than one at coastal water of the Nackdong. Residual current which was averaged during 12hours dominantly appeared the dominant direction from the southwestern part of the Nackdong to the northeastern part of it. The eastward current appeared at the eastern coast of Gaduck Is. Base on the results of the velocity field, the quantifying of the dispersion of SS was estimated by the method of numerical tracer related to the Lagrangian method. The significant range of the dispersion of the SS from the Nackdong was from the eastern coast of Gaduck Is, to the coastal areas of Busan, Korea. The estimated range of the dispersion of the SS using the SeaWiFS and Landsat satellite data was similar to the estimated results using the numerical model.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.2
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• pp.247-258
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• 2003

In this paper, we present a pen-shaped input device equipped with accelerometers and gyroscopes that measure inertial movements when a user writes on 2 or 3 dimensional space with the pen. The measurements from gyroscope are integrated once to find the attitude of the system and are used to compensate gravitational effect in the accelerations. Further, the compensated accelerations are integrated twice to yield the position of the system, whose basic concept stems from the field of inertial navigation. However, the accuracy of the position measurement significantly deteriorates with time due to the integrations involved in recovering the handwriting trajectory This problem is common in the inertial navigation system and is usually solved by the periodic or aperiodic calibration of the system with external reference sources or other information in the filed of inertial navigation. In the presented paper, the calibration of the position or velocity is performed on-line and off-line. In the on-line calibration stage, the complementary filter technique is used, where a Kalman filter plays an important role. In the off-line calibration stage, the constant component of the resultant navigational error of the system is removed using the velocity information and motion detection algorithm. The effectiveness and feasibility of the presented system is shown through the experimental results.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.120-130
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• 1999

In this paper, we show that the instantaneous phase current of the bifiler-wound hybrid stepping motor is dependent of lead angle and that the information of motor position is obtained from the instantaneous phase current at ${\pi}/2$ by the theoretical formular and its computer simulation results. From the facts, we design the microcontroller-based motor position sensorless controller of optimal lead angle, which generates the excitation pulses for the closed-loop drives. The controller is consist of microcontroller which has the function of A/D converter, programmable input/output timer, and the transfer table which has the values of optimal lead angle depending on motor velocity, and ROM which has the transfer table of the values of lead angle depending on velocity of motor and the values of instantaneous phase current at ${\pi}/2$. From the design of microcontroller-based controller, we minimize the external interface circuit and obtain flexibility by changing the contents of ROM transfer tables and the control software. We confirm that the designed controller drives the bifilar-wound hybrid stepping motor is the mode of optimal lead angle by comparing the instananeous phase current experimental results and computer simulation results.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.1
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• pp.43-51
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• 2012

Due to the increasing demand to utilize water fronts and water resource effectively, a multi-dimensional model that provides detailed hydraulic characteristics is required in order to improve the decision making process. An EFDC model is a kind of multi-dimension model, and it requires detailed 3D (3-dimensional) terrain in order to simulate the hydraulic characteristics of stream flow. In the case of 3D terrain creation, especially river reaches, measurement resolution and spatial interpolation methods affect the detailed 3D topography which uses input data for EFDC simulation. Such results make hydraulic characteristics to be varied. This study aims to examine EFDC simulation results depending on the 3D topographies derived by separate measurement resolution and spatial interpolation methods. The study area is at the confluence of the Nakdong and Kuemho Rivers and the event rain implemented was Typhoon Ewiniar in 2006. As a result, in the case of the area-elevation curve, the difference by means of the interpolation methods was significant when applying the same measurement resolution, except at 160m resolution. Furthermore, when the measurement resolution was 80m or above, the difference in a cross-section was occurred. Meanwhile, the water level changes between interpolation methods were insignificant by the measurement resolution except when the Kriging method was used for the 160m measurement data. Velocity changes emerged according to the interpolation methods when measurement resolution was 80m or above and the Kriging method resulted in a velocity that had a considerable gap in relation to the results from other methods at a measurement resolution of 160m.