• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.2
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• pp.89-95
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• 2009

Tracking the Maximum Power Point(MPP) of a photovoltaic(PV) array is usually an essential part of a PV system. The problem considered by MPPT techniques is to find the voltage $V_{MPP}$ or current $I_{MPP}$ at which a PV array should operate to generate the maximum power output PMPP under a given temperature and irradiance. The MPPT control methods, such as the perturb and observe method and the incremental conductance method require microprocessor or DSP to determine if the duty cycle should be increased or not. This paper proposes a simple and fast analog MPPT method. The proposed control scheme will track the MPP very fast and its hardware implementation is so simple, compared with the conventional techniques. The new algorithm has successfully tracked the MPP, even in case of rapidly changing atmospheric conditions, and Has higher efficiency than ordinary algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.5C
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• pp.411-421
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• 2002

In this paper, we present a new survivor path memory management method and a dedicated hardware architecture for the design of high-speed Viterbi decoders in modern digital communication systems. In the proposed method, a novel use of k-starting node number deciding circuits enables to acheive the immediate traceback of the merged survivor path from which we can decode output bits, and results in smaller survivor path memory size and processing delay time than the previously known methods. Also, in the proposed method, the survivor path memory can be constructed with ease using a simple standard dual-ported memory since one read-pointer and one write-pointer, that are updated at the same rate, are required for managing the survivor path: the previously known algorithms require either complex k-ported memory structure or k-times faster read capability than write. With a moderate hardware cost for immediate traceback capability the proposed method is superior to the previously known methods for high-speed Viterbi decoding.

• Journal of IKEEE
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• v.23 no.4
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• pp.1360-1365
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• 2019

In this paper, we describe a sound source localization(SSL) system which can be applied to mobile robot and automatic control systems. Usually the SSL method finds the Interaural Time Difference, the Interaural Level Difference, and uses the geometrical principle of microphone array. But here we proposed another approach based on the deep neural network to obtain the horizontal directional angle(azimuth) of the sound source. We pick up the sound source signals from the two microphones attached symmetrically on both sides of the robot to imitate the human ears. Here, we use difference of spectral distributions of sounds obtained from two microphones to train the network. We train the network with the data obtained at the multiples of 10 degrees and test with several data obtained at the random degrees. The result shows quite promising validity of our approach.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.4
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• pp.11-21
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• 2000

This paper proposes a new algorithm for a mobile robot that detects and tracks a moving target, keeping it in the view range of the robot. The sensor system consists of a camera and a line light source. The camera system is placed so that the line light projected into the ground from the light source forms its image along the horizontal center line of the CCD array of the camera. The deformation of the line image from the horizontal center line contains the information on existence of a moving object, its velocity, and position. Since the proposed algorithm reduces the region of the image to be searched, it reduces the computational complexity significantly comparing to the conventional image processing algorithms. The performance of the proposed algorithm has been tested by implementing on a mobile robot.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.6
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• pp.147-155
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• 1989

In this paper, a real-time implementation of the TWS(track-while-scan) system using the high-speed DSP (digital signal processor) TMS320C25 is described. First, attempts have been made to investigate the FWL (finite word length) effect, which is caused by employing a fixed point arithmetic, of implementing the Kalman filter. The real-time TWS system consists of TWS arithmetic unit, scan converter, and system controller. In addition, the TWS system is in tegrated in the Multi-Bus. In experiment, it is observed that by employing the floating point arithmetic the computation time of 0.35sec is required for tracking 8 targets simultaneously, while 0.28sec is required for the fixed point arithmetic. Since the TWS system is designed to track up to 8 targets simultaneously, we conclude that the system is enough to process Kalman filter in a real-time.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.533-540
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• 2008

In the sum and difference pattern synthesis problem of the equi-spaced monopulse tracking linear array antennas, an efficient numerical approach to deriving the relative excitation current weights of antenna elements is presented for the desired patterns. This method is based on the optimum perturbation of null points which are inherent to the Schelkunoffs polynomial representing the pattern array factor. Accordingly, opposite to the conventional method in which the excitation weights are directly optimized, this method is advantageous in that the patterns with the desired individual sidelobe levels(SLLs) and the corresponding excitation weights are easily synthesized by the control of null points. Furthermore, it is showed that two types of difference patterns can be synthesized as imposing the different initial values of null points in the optimization process. The proposed method is numerically validated by synthesizing the patterns with the arbitrary SLLs and substituting the extracted results into the array factor equation.

• Journal of KIISE:Software and Applications
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• v.35 no.7
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• pp.452-461
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• 2008

Binary diffing is a method to find differences in similar binary executables such as two different versions of security patches. Previous diffing methods using flow information can detect control flow changes, but they cannot track constant value changes. Biffing methods using assembly instructions can detect constant value changes, but they give false positives which are due to compiling methods such as instruction reordering. We present a binary diffing method and its implementation named SCV which utilizes both structure and value information. SCV summarizes structure and constant value information from disassembled code, and matches the summaries to find differences. By analyzing a Microsoft Windows security patches, we showed that SCV found necessary differences caused by constant value changes which the state-of-the-art binary diffing tool BinDiff failed to find.

• Korean Journal of Ecology and Environment
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• v.51 no.3
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• pp.245-252
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• 2018

Stable isotope tracers were first applied to evaluate the Microcystis cell assimilation efficiency of bivalves, since the past identification method has been limited to tracking the changes of each chl-a, clearity, and nutrient. The filter-feeders (Sinanodonta woodiana and Unio douglasiae) were assessed under the condition of cyanobacteria (Microcystis aeruginosa) blooms through an in mesocosm experiment using $^{13}C$ and $^{15}N$ dual isotope tracers. chl-a concentration in the treatment mesocosm was dramatically decreased after the beginning of the second day, ranging from 116 to $66{\mu}g\;L^{-1}$. In addition, the incorporated $^{13}C$ and $^{15}N$ atom % in the S. woodiana bivalve showed higher values than U. douglasiae bivalves. The results demonstrate that U. douglasiae has less capacity to assimilate toxic cyanobacteria derived from diet. Our results therefore also indicate that S. woodiana can eliminate the toxin more rapidly than U. douglasiae, having a larger detoxification capacity.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.4
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• pp.269-279
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• 2005

Numerical simulations were done using depth integrated ADCIRC model in order to evaluate dynamic response on the inner Saemankeum reservoir due to flood flow and gate operation for the both situations of dike construction and inner development. According to 2-dimensional dynamic flood routing, temporal variation of hydrographs shows sensitive at upstream riverine region while it becomes stable from the center part of the reservoir due to sudden expansion of physical changes. Dynamic response of hydraulic changes such as water surface elevation and velocity on the inner region arises suddenly by gate operation and more rapidly after the inner development than dike construction. Temporal surface fluctuation arises during inflowging of outer sea water and propagates upstream up to 10km to 16km in accordance with inner development status.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.4
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• pp.370-377
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• 2011

Korea Astronomy and Space Science Institute(KASI) has been developing one mobile SLR system since 2008 named as ARGO-M. Control logic in real-time laser ranging and data processing for normal point from the ranging data are key elements in the operation system of ARGO-M. KASI operation system team performed software logic analysis and related operations for SLR observation with help of Graz SLR station in Austria. This paper describes the algorithm required for SLR operation based on the method in Graz station. We figured out the essential logic for SLR operation and the remedy for the observation quality enhancement through this study.