• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.1
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• pp.141-148
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• 2021

In some intersections or busy traffic roads, there are more pedestrians in a specific period of time, and there are many traffic accidents caused by road congestion. Especially at the intersection where there are schools nearby, it is particularly important to protect the traffic safety of students in busy hours. In the past, when designing traffic lights, the safety of pedestrians was seldom taken into account, and the identification of motor vehicles and traffic optimization were mostly studied. How to keep the road smooth as far as possible under the premise of ensuring the safety of pedestrians, especially students, will be the key research direction of this paper. This paper will focus on person, motorcycle, bicycle, car and bus recognition research. Through investigation and comparison, this paper proposes to use YOLO v4 network to identify the location and quantity of objects. YOLO v4 has the characteristics of strong ability of small target recognition, high precision and fast processing speed, and sets the data acquisition object to train and test the image set. Using the statistics of the accuracy rate, error rate and omission rate of the target in the video, the network trained in this paper can accurately and effectively identify persons, motorcycles, bicycles, cars and buses in the moving images.

• Journal of the Korean earth science society
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• v.40 no.5
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• pp.502-517
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• 2019

Global warming and rapid climate change have long affected the characteristics of typhoons in the Northwest Pacific, which has induced increasing devastating disasters along the coastal regions of the Korean peninsula. Synthetic Aperature Radar (SAR), as one of the microwave sensors, makes it possible to produce high-resolution sea surface wind field around the typhoon under cloudy atmospheric conditions, which has been impossible to obtain the winds from satellite optical and infrared sensors. The Geophysical Model Functions (GMFs) for sea surface wind retrieval from SAR data requires the input of wind direction, which should be based on the accurate estimation of the center of the typhoon. This study estimated the typhoon centers using Sentinel-1A images to improve the problem of typhoon center detection method and to reflect it in retrieving the sea surface wind. The results were validated by comparing with the typhoon best track data provided by the Korea Meteorological Administration (KMA) and Japan Meteorological Agency (JMA), and also by using infrared images of Himawari-8 satellite. The initial center position of the typhoon was determined by using VH polarization, thereby reducing the possibility of error. The detected center showed a difference of 23.76 km on average with the best track data of the four typhoons provided by the KMA and JMA. Compared to the typhoon center estimated by Himawari-8 satellite, the results showed an average spatial variation of 11.80 km except one typhoon located near land with a large difference of 58.73 km. This result suggests that high-resolution SAR images can be used to estimate the center and retrieve sea surface wind around typhoons.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1A
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• pp.93-98
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• 2004

Serial ATA interface Is inexpensive comparatively and performance is superior. So it is suitable technology in demand that now require data transmission and throughput of high speed. This paper describes a design and implementation of Serial ATA Link layer about error detection and 8b/10b encoder/decoder for DC balance in frequency 150MHz. The 8b/10b Encoder is partitioned into a 5b/6b plus a 3b/4b coder. The logical model of the block is described by using Verilog HDL at register transistor level and the verified HDL is synthesized using standard cell libraries. And it is fabricated with $0.35{\mu}m$ Standard CMOS Cell library and the chip size is about $1500{\mu}m\;*\;1500{\mu}m$. The function of this chip has been verified and tested using testboard with FPGA equipment and IDEC ATS2 test equipment. It is used to frequency of 100MHz in verification processes and supply voltage 3.3V. The result of testing is well on the system clock 100MHz. The designed and verified each blocks may be used IP in the field of high speed serial data communication.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.8
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• pp.1-11
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• 2012

The multi-code spread spectrum communication system, which spreads data bit stream by multiplexing orthogonal codes, can transmit data in high rate. However it needs the high-cost good linear amplifier because of the multi-level output signal. In order to overcome this drawback several systems making the amplitude of output signal constant with Walsh codes have been proposed. Recently constant amplitude pre-coded multi-code spread spectrum systems using extended m-sequence have been proposed. In this paper we consider an extended m-sequence based constant amplitude multi-code spread spectrum system with code set partitioning. By grouping the orthogonal codes into 4 subsets, not only is the computational complexity of the transceiver reduced but BER performance also improves. It has been shown that parity checking on four detected codes at the receiver can correct code detection error and result in BER performance enhancement. In this paper we propose a improved parity check receiver. We carried out computer simulation to verify feasibility of the proposed algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2C
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• pp.156-165
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• 2006

In this paper, a new intelligent moving target tracking and surveillance system basing on the pan/tilt-embedded stereo camera system is suggested and implemented. In the proposed system, once the face area of a target is detected from the input stereo image by using a YCbCr color model and phase-type correlation scheme and then, using this data as well as the geometric information of the tracking system, the distance and 3D information of the target are effectively extracted in real-time. Basing on these extracted data the pan/tilted-imbedded stereo camera system is adaptively controlled and as a result, the proposed system can track the target adaptively under the various circumstance of the target. From some experiments using 480 frames of the test input stereo image, it is analyzed that a standard variation between the measured and computed the estimated target's height and an error ratio between the measured and computed 3D coordinate values of the target is also kept to be very low value of 1.03 and 1.18$\%$ on average, respectively. From these good experimental results a possibility of implementing a new real-time intelligent stereo target tracking and surveillance system using the proposed scheme is finally suggested.

• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.51-56
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• 2009

Time synchronization algorithm in wireless sensor networks is essential to various applications such as object tracking, data encryption, duplicate detection, and precise TDMA scheduling. This paper describes CDRS that is a time synchronization algorithm using the Clock Drift rate and Reference Signals between two sensor nodes. CDRS is composed of two steps. At first step, the time correction is calculated using offset and the clock drift rate between the two nodes based on the LTS method. Two nodes become a synchronized state and the time variance can be compensated by the clock drift rate. At second step, the synchronization node transmits reference signals periodically. This reference signals are used to calculate the time difference between nodes. When this value exceeds the maximum error tolerance, the first step is performed again for resynchronization. The simulation results on the performance analysis show that the time accuracy of the proposed algorithm is improved, and the energy consumption is reduced 2.5 times compared to the time synchronization algorithm with only LTS, because CDRS reduces the number of message about 50% compared to LTS and reference signals do not use the data space for timestamp.

• Convergence Security Journal
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• v.11 no.1
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• pp.71-77
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• 2011

NCW(Network Centric- Warfare) encompasses the concept to use computer data processing and network linkage communications techniques, share information and furthermore, enhance the effectiveness of computer-operating systems. As IT(Information & Technology) have become developed in the recent years, the existing warfare system-centered conventional protocol is not use any longer. Instead, network-based NCW is being widely-available, today. Under this changing computer environment, it becomes important to establish algorithm and build the stable communication systems. Tools to identify malign node factors through Wireless Ad-hoc network cause a tremendous error to analyze and use paths of even benign node factors misreported to prove false without testing or indentifying such factors to an adequate level. These things can become an obstacle in the process of creating the optimum network distribution environment. In this regard, this thesis is designed to test and identify paths of benign node factors and then, present techniques to transmit data through the most significant open short path, with the tool of MP-SAR Protocol, security path search provider, in Ad-hoc NCW environment. Such techniques functions to identify and test unnecessary paths of node factors, and thus, such technique users can give an easy access to benign paths of node factors.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.609-616
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• 2017

In this paper, we propose an algorithm to obtain more stable and high recognition rate by using left and right rotation information of input image in order to obtain a stable recognition rate in face recognition. The proposed algorithm uses the facial image as the input information in the web camera environment to reduce the size of the image and normalize the information about the brightness and color to obtain the improved recognition rate. We apply Principal Component Analysis (PCA) to the detected candidate regions to obtain feature vectors and classify faces. Also, In order to reduce the error rate range of the recognition rate, a set of data with the left and right $45^{\circ}$ rotation information is constructed considering the directionality of the input face image, and each feature vector is obtained with PCA. In order to obtain a stable recognition rate with the obtained feature vector, it is after scattered in the eigenspace and the final face is recognized by comparing euclidean distant distances to each feature. The PCA-based feature vector is low-dimensional data, but there is no problem in expressing the face, and the recognition speed can be fast because of the small amount of calculation. The method proposed in this paper can improve the safety and accuracy of recognition and recognition rate faster than other algorithms, and can be used for real-time recognition system.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.801-806
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• 2018

Germanium crystals have a dead layer that causes efficiency deterioration because the layer is not useful for detection but strongly weakens the photons. Thus, when the data provided by the manufacturer is used in the detector simulation model, there is a slight difference between the calculated efficiency and the measured efficiency.The shape and dimensions of the high purity germanium (HPGe) detector were determined by CT scans to accurately characterize the shape for the Monte Carlo roll simulation. It is found that the adjustment of the dead layer is a good match with the relative deviation of ${\pm}3%$ between the measurement efficiency and the simulation efficiency at the energy range of 50 - 1500 keV. Simulation data were compared by varying the thickness of the dead layer. The new Monte Carlo simulations were compared with the experimental results to obtain new blank layer thicknesses. The difference in dead layer results for the 1.5 mm thick end cap simulation model in 1.4 and 1.6 mm thick End Cap simulation models was a systematic error due to the accuracy of the end cap dimensions. After considering all errors including statistical errors and systematic errors, the thickness of the detector was calculated as $1.02{\pm}0.14mm$. Therefore, it was confirmed that the increase in the thickness of the dead layer causes the effect to be effected on the efficiency reduction.

• Journal of Korea Water Resources Association
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• v.54 no.7
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• pp.535-544
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• 2021

Agricultural water occupies 48% of water demand, and management of agricultural reservoirs is essential for water resources management within agricultural basins. For more efficient use of agricultural water, monitoring the distribution of water resources in agricultural reservoirs and agricultural basins is required. Therefore, in this study, three threshold determination methods (i.e., fixed threshold, Otsu threshold, Kittler-Illingworth (KI) threshold) were compared to detect terrestrial water bodies using Sentinel-1 images for 3 years from 2018 to 2020. The purpose of this study was to evaluate methods for determining threshold values to more accurately estimate the reservoir area. In addition, by analyzing the relationship between the water surface and water storage at the Edong, Gosam, and Giheung reservoirs, water storage based on the SAR image was estimated and validated with observations. The thresholding method for detecting a waterbody was found to be the most accurate in the case of the KI threshold, and the water storage estimated by the KI threshold indicated a very high agreement (r = 0.9235, KGE' = 0.8691). Although the seasonal error characteristics were not observed, the problem of underestimation at high water levels may occur; the relationship between the water surface and the water storage could change rapidly. Therefore, it is necessary to understand the relationship between the water surface area and water storage through ground observation data for a more accurate estimation of water storage. If the use of SAR data through water resources satellites becomes possible in the future, based on the results of this study, it is judged that it will be beneficial for monitoring water storage and managing drought.