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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Institute of Electronics and Information Engineers
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The Institute of Electronics Engineers of Korea
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Volume & Issues
Volume 50, Issue 12 - Dec 2013
Volume 50, Issue 11 - Nov 2013
Volume 50, Issue 10 - Oct 2013
Volume 50, Issue 9 - Sep 2013
Volume 50, Issue 8 - Aug 2013
Volume 50, Issue 7 - Jul 2013
Volume 50, Issue 6 - Jun 2013
Volume 50, Issue 5 - May 2013
Volume 50, Issue 4 - Apr 2013
Volume 50, Issue 3 - Mar 2013
Volume 50, Issue 2 - Feb 2013
Volume 50, Issue 1 - Jan 2013
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Iterative Weighted MMSE Beamforming for Downlink multiuser MISO System
Choi, Ilgyu ; Hwang, Youngsoo ; Lee, Chungyong ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 3~8
DOI : 10.5573/ieek.2013.50.3.003
Conventional MMSE beamforming scheme shows better performance than ZF or MF beamforming, but it does not aim increase of sum rate. This paper proposes sum rate maximizing scheme by representing sum rate as a function of weighted MSE. Proposed scheme increases sum rate iteratively by updating weights and beam whose initial form is conventional MMSE beam. Simulation result shows sum rate of proposed scheme is higher than those of conventional schemes and increases as the number of users increases.
Interference Aware Receiver Filtering for Wireless Ad Hoc Networks
Shin, Sungpil ; Lee, Byungju ; Park, Sunho ; Shim, Byonghyo ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 9~15
DOI : 10.5573/ieek.2013.50.3.009
Recent works on ad hoc network study have shown that achievable throughput can be made to scale linearly with the number of receive antennas even if the transmitter has only a single antenna. In this paper, we propose a non-parametric linear minimum mean square error (MMSE) receiver for achieving further gain in performance when the channel state information at receiver (CSIR) of interferers is imperfect. The key feature to make our approach effective is to exploit the autocorrelation of the received signal. In fact, by incorporating the desired channel information on top of the observations including interference and noise only, the proposed method achieves large fraction of the optimal MMSE transmission capacity without transmission rate loss. From the SINR analysis as well as transmission capacity simulations in realistic ad hoc network system, we show that the proposed non-parametric linear MMSE receiver brings substantial performance gain over existing multiple receive antenna algorithms.
Analysis of Symmetric and Asymmetric Multiple Coupled Line on the Multi-layer Substrate
Kim, Yoonsuk ; Kim, Minsu ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 16~22
DOI : 10.5573/ieek.2013.50.3.016
A general characterization procedure based on the extraction of a 2n-port admittance matrix corresponding to n uniform coupled lines on the multi-layered substrate using the Finite-Difference Time-Domain (FDTD) technique is presented. In this paper, the frequency-dependent normal mode parameters are obtained from the 2n-port admittance matrix to analyze multi-layered asymmetric coupled line structure, which in turn provides the frequency-dependent propagation constant, effective dielectric constant, and line-mode characteristic impedances. To illustrate the technique, several practical coupled line structures on multi-layered substrate have been simulated. Especially, embedded conductor structures have been simulated. Comparisons with Spectral Domain Method are given, and their results agree well. It is shown that the FDTD based time domain characterization procedure is an excellent broadband simulation tool for the design of multiconductor coupled lines on multilayered PCBs as well as thick or thin hybrid structures.
Scheme for Verification Between Mobile Devices in a Service with Expiration Time by Using Zero-knowledge Proof
Park, Young-Hoon ; Seo, Seung-Woo ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 23~32
DOI : 10.5573/ieek.2013.50.3.023
As the mobile communication technology is developed, the services for communication between the mobile devices are provided, and the amount of usage is increasing tremendously. For the device-to-device communication, the device should be verified if it is a service member. The existing verification schemes include interactions with the third party, while this may cause the problems that the bandwidth is dissipated and the devices which are out of the communication range of the base station cannot communicate with other devices. To solve such problems, we propose a new scheme for verification between mobile devices without interaction of third party. For the proposed scheme, we develop and employ a new zero-knowledge proof protocol, which verifies the device`s membership and its expiration time. Furthermore, the scheme guarantees privacy of the mobile device since it checks the encrypted verification message without decrypting, and protects replaying attack since it uses challenge-response method.
A 13.56 MHz CMOS Multi-Stage Rectifier for Wireless Power Transfer in Biomedical Applications
Cha, Hyouk-Kyu ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 35~41
DOI : 10.5573/ieek.2013.50.3.035
An efficient multi-stage rectifier for wireless power transfer in deep implant medical devices is implemented using
CMOS technology. The presented three-stage rectifier employs a cross-coupled topology to boost a small input AC signal from the external device to produce a 1.2-1.5 V output DC signal for the implant device. The designed rectifier achieves a maximum measured power conversion efficiency of 70% at 13.56 MHz under the conditions of a low 0.6-Vpp RF input signal with a
output load resistance.
A 2-Gbps Simultaneous Bidirectional Inductively-Coupled Link
Jeon, Minki ; Yoo, Changsik ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 42~49
DOI : 10.5573/ieek.2013.50.3.042
A simultaneous bidirectional inductively-coupled link is presented. In the conventional inductively-coupled link, data can be bidirectionally transmitted through channel, however not simultaneously. We propose simultaneous bidirectional link for higher data rate with effective echo cancellation technique. Each chip performs TX-mode and RX-mode simultaneously. Instead chip stacking for test, similar test enviroment is realized in a single chip that is fabricated in a
standard CMOS technology.
Design of Parallel Decimal Multiplier using Limited Range of Signed-Digit Number Encoding
Hwang, In-Guk ; Kim, Kanghee ; Yoon, WanOh ; Choi, SangBang ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 50~58
DOI : 10.5573/ieek.2013.50.3.050
In this paper, parallel decimal fixed-point multiplier which uses the limited range of Singed-Digit number encoding and the reduction step is proposed. The partial products are generated without carry propagation delay by encoding a multiplicand and a multiplier to the limited range of SD number. With the limited range of SD number, the proposed multiplier can improve the partial product reduction step by increasing the number of possible operands for multi-operand SD addition. In order to estimate the proposed parallel decimal multiplier, synthesis is implemented using Design Compiler with SMIC 180nm CMOS technology library. Synthesis results show that the delay of proposed parallel decimal multiplier is reduced by 4.3% and the area by 5.3%, compared to the existing SD parallel decimal multiplier. Despite of the slightly increased delay and area of partial product generation step, the total delay and area are reduced since the partial product reduction step takes the most proportion.
Area-efficient Interpolation Architecture for Soft-Decision List Decoding of Reed-Solomon Codes
Lee, Sungman ; Park, Taegeun ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 59~67
DOI : 10.5573/ieek.2013.50.3.059
Reed-Solomon (RS) codes are powerful error-correcting codes used in diverse applications. Recently, algebraic soft-decision decoding algorithm for RS codes that can correct the errors beyond the error correcting bound has been proposed. The algorithm requires very intensive computations for interpolation, therefore an efficient VLSI architecture, which is realizable in hardware with a moderate hardware complexity, is mandatory for various applications. In this paper, we propose an efficient architecture with low hardware complexity for interpolation in soft-decision list decoding of Reed-Solomon codes. The proposed architecture processes the candidate polynomial in such a way that the terms of X degrees are processed in serial and the terms of Y degrees are processed in parallel. The processing order of candidate polynomials adaptively changes to increase the efficiency of memory access for coefficients; this minimizes the internal registers and the number of memory accesses and simplifies the memory structure by combining and storing data in memory. Also, the proposed architecture shows high hardware efficiency, since each module is balanced in terms of latency and the modules are maximally overlapped in schedule. The proposed interpolation architecture for the (255, 239) RS list decoder is designed and synthesized using the DongbuHitek
standard cell library, the number of gate counts is 25.1K and the maximum operating frequency is 200 MHz.
Time Value and Importance based Classified Job Scheduling
Shim, JeongYon ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 71~77
DOI : 10.5573/ieek.2013.50.3.071
In the information flooded situation having many thing to do, the efficient scheduling of energy and time is regarded as a very important thing for the busy modern people. Because the efficient time scheduling already became a very important key factor for a successful life, the more elaborately designed intelligent system than the previous simple event oriented scheduling system should be supported. Accordingly in this paper we propose Classified Job Scheduling System in which jobs are classified by Time value & Importance and allocated to Time frame efficiently. Especially the new method is proposed with the policy that processes the job with high time value first and concurrently allocates the job of low time vale & high importance to the preempted fixed area of time frame for continuous processing of job which has a key of success in the future.
Adaptive Mapping Information Management Scheme for High Performance Large Sale Flash Memory Storages
Lee, Yongju ; Kim, Hyunwoo ; Kim, Huijeong ; Huh, Taeyeong ; Jung, Sanghyuk ; Song, Yong Ho ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 78~87
DOI : 10.5573/ieek.2013.50.3.078
NAND flash memory has been widely used as a storage medium in mobile devices, PCs, and workstations due to its advantages such as low power consumption, high performance, and random accessability compared to a hard disk drive. However, NAND flash cannot support in-place update so that it is mandatory to erase the entire block before overwriting the corresponding page. In order to overcome this drawback, flash storages need a software support, named Flash Translation Layer. However, as the high performance mass NAND flash memory is getting widely used, the size of mapping tables is increasing more than the limited DRAM size. In this paper, we propose an adaptive mapping information caching algorithm based on page mapping to solve this DRAM space shortage problem. Our algorithm uses a mapping information caching scheme which minimize the flash memory access frequency based on the analysis of several workloads. The experimental results show that the proposed algorithm can increase the performance by up to 70% comparing with the previous mapping information caching algorithm.
Re-coloring Methods using the HSV Color Space for people with the Red-green Color Vision Deficiency
Kim, Hyun-Ji ; Cho, Jae-Young ; Ko, Sung-Jea ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 91~101
DOI : 10.5573/ieek.2013.50.3.091
This paper proposes a new re-coloring method for the people with the red-green color vision deficiency (CVD). These people have difficulty in discriminating the red and green colors since they abnormally perceive the hue and luminance value of the colors. We introduce a color transformation that adjusts the hue and luminance value in HSV color space. The color transformation is determined according to the severity of CVD. Our aim is to maintain the color differences in original image while maintaining the recolored image to be natural to the people with normal color vision. Experimental results show that the proposed method can yield more comprehensible images for the people with red-green CVD while maintaining the naturalness of the recolored images.
Extraction and Complement of Hexagonal Borders in Corneal Endothelial Cell Images
Kim, Eung-Kyeu ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 102~112
DOI : 10.5573/ieek.2013.50.3.102
In this paper, two step processing method of contour extraction and complement which contain hexagonal shape for low contrast and noisy images is proposed. This method is based on the combination of Laplacian-Gaussian filter and an idea of filters which are dependent on the shape. At the first step, an algorithm which has six masks as its extractors to extract the hexagonal edges especially in the corners is used. Here, two tricorn filters are used to detect the tricorn joints of hexagons and other four masks are used to enhance the line segments of hexagonal edges. As a natural image, a corneal endothelial cell image which usually has regular hexagonal form is selected. The edge extraction of hexagonal shapes in corneal endothelial cell is important for clinical diagnosis. The proposed algorithm and other conventional methods are applied to noisy hexagonal images to evaluate each efficiency. As a result, this proposed algorithm shows a robustness against noises and better detection ability in the aspects of the output signal to noise ratio, the edge coincidence ratio and the extraction accuracy factor as compared with other conventional methods. At the second step, the lacking part of the thinned image by an energy minimum algorithm is complemented, and then the area and distribution of cells which give necessary information for medical diagnosis are computed.
Sub-Pixel Rendering Algorithm Using Adaptive 2D FIR Filters
Nam, Yeon Oh ; Choi, Ik Hyun ; Song, Byung Cheol ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 113~121
DOI : 10.5573/ieek.2013.50.3.113
In this paper, we propose a sub-pixel rendering algorithm using learning-based 2D FIR filters. The proposed algorithm consists of two stages: the learning and synthesis stages. At the learning stage, we produce the low-resolution synthesis information derived from a sufficient number of high/low resolution block pairs, and store the synthesis information into a so-called dictionary. At the synthesis stage, the best candidate block corresponding to each input high-resolution block is found in the dictionary. Next, we can finally obtain the low-resolution image by synthesizing the low-resolution block using the selected 2D FIR filter on a sub-pixel basis. On the other hand, we additionally enhance the sharpness of the output image by using pre-emphasis considering RGB stripe pattern of display. The simulation results show that the proposed algorithm can provide significantly sharper results than conventional down-sampling methods, without blur effects and aliasing.
Detection Algorithm of an Active Video Player Region in the Monitor Screen
Kim, Hak Gu ; Song, Byung Cheol ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 122~128
DOI : 10.5573/ieek.2013.50.3.122
This paper presents a detection algorithm that accurately finds the active area of a video player on monitors or smart TVs. Unlike the previous approaches, temporal difference-based detection algorithms or hooking programs, the proposed detection algorithm can locate the active video player by using the spatial and temporal correlation and a corner detection filter. First, an initial location of the video player is found using conventional temporal difference-based detection. Then, starting from the initial location, the four corners of the active video player are detected by the spatial edge information and the corner detection filter. The experimental results show that proposed algorithm provides fast detection speed and high accuracy.
A Study on 8-Directional Complex Wavelet Transform for Efficient Image Processing
Shin, Seong ; Moon, Sung Ryong ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 129~138
DOI : 10.5573/ieek.2013.50.3.129
This paper is a study on Dual Tree Complex Wavelet Transform, which improved directional information for efficient image processing. Dual Tree Complex Wavelet Transform satisfies characteristics of shift invariance, and includes 6 directional information, which is more than previous Discrete Wavelet Transform. However, in images of buildings, there are many horizontal and vertical edge components. Therefore, all the high-frequency components of image are not expressed by 6 directional information subbands. This paper proposes 8-directional Complex Wavelet Transform with excellent high-frequency separation features by creating horizontal vertical(
) subband besides 6 directional information subband of previous Dual Tree Complex Wavelet Transform. The proposed method can create and combine various directional information subbands according to features of image. Performance is evaluated by applying the method to noise removal.
Enhanced Amplitude Panning for Virtual Source Imaging
Hyun, Dong-Il ; Park, Young-Cheol ; Youn, Dae Hee ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 139~145
DOI : 10.5573/ieek.2013.50.3.139
In this paper, the problems of the conventional amplitude panning method for a stereophonic panning system are analyzed. We observed that the distortion showed a feedforward comb filter response. As a remedy to this distortion, we propose a stereophonic panning system using a feedback comb filter. The comb filter is designed to minimize the difference between interaural level difference(ILD) of the proposed system and that of HRTF because ILD is most salient cue for the perception of the source direction. The proposed system is configured to operate selectively for the frequency band related to the source direction. The performance of the proposed system is verified by subjective listening tests.
An Intensity Based Self-referencing Fiber Optic Sensor Using Tunable Fabry-Perot Filter and FBG
Choi, Sang-Jin ; Pan, Jae-Kyung ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 146~152
DOI : 10.5573/ieek.2013.50.3.146
In this paper, we have proposed and experimentally demonstrated an intensity-based self-referencing fiber optic sensor. The proposed fiber optic sensor consists of a broadband light source (BLS), fiber Bragg grating (FBG), tunable Fabry-Perot (F-P) filter, and LabVIEW program. We define the measurement parameter (X) and the calibration parameter (
) to determine the transfer function(H) of the self-referencing fiber optic sensor, and the validity of the theoretical analysis is confirmed by experiments. The self-referencing characteristic for the proposed system has been validated by showing that the measurement parameter (X) is invariant for BLS optical power attenuations of 0 dB, 3 dB, and 6 dB. Also, the measured result is irrelevant to the FBGs with different characteristics. This means that the proposed fiber optic sensor offers the flexibility for determining the FBGs needed for implementation. Experimental results for the proposed fiber optic sensor are in good agreement with a theoretical analysis for BLS optical power attenuations and for three FBG pairs with different characteristics. So, the proposed fiber optic sensor has several benefits, including the self-referencing characteristic and the flexibility to determine the FBGs.
Structured Static Output Feedback Stabilization
Lee, Joon Hwa ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 155~159
DOI : 10.5573/ieek.2013.50.3.155
In this paper, a nonlinear matrix inequality problem and a nonlinear optimization problem are proposed for obtaining a structured static output feedback controller. The proposed nonlinear optimization problem has LMI (Linear Matrix Inequality) constraints and a nonlinear objective function. Using the conditional gradient method, the nonlinear optimization problem can be solved. A numerical example shows the effectiveness of the proposed approach.
Localization of A Moving Vehicle using Backward-looking Camera and 3D Road Map
Choi, Sung-In ; Park, Soon-Yong ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 160~173
DOI : 10.5573/ieek.2013.50.3.160
In this paper, we propose a new visual odometry technique by combining a forward-looking stereo camera and a backward-looking monocular camera. The main goal of the proposed technique is to identify the location of a moving vehicle which travels long distance and comes back to the initial position in urban road environments. While the vehicle is moving to the destination, a global 3D map is updated continuously by a stereo visual odometry technique using a graph theorem. Once the vehicle reaches the destination and begins to come back to the initial position, a map-based monocular visual odometry technqieu is used. To estimate the position of the returning vehicle accurately, 2D features in the backward-looking camera image and the global map are matched. In addition, we utilize the previous matching nodes to limit the search ranges of the next vehicle position in the global map. Through two navigation paths, we analyze the accuracy of the proposed method.
Improvement of Address Discharge Characteristics Using Wall Charge on Common Electrodes in AC PDP
Cho, Byung-Gwon ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 174~178
DOI : 10.5573/ieek.2013.50.3.174
A modified driving waveform is proposed to improve the address discharge characteristics using wall charge on the common electrodes in plasma display panel. In the driving scheme of plasma display, after a reset period, the negative charge are accumulated on two front electrodes and positive wall charge are accumulated on the address electrode. As the address discharge during an address period is produced when the scan and address pulses are applied at the same time, negative charge on the scan electrodes and positive charge on the address electrodes are mainly used. On the other hand, as the voltage are only maintained without applying the waveform during an address period on the common electrodes, the wall charge is not used on the common electrodes. In this paper, the address discharge characteristics are investigated with changing pulse applying time and applied voltage amplitude on the common electrodes and consequently the producing time of an address discharge are shortened about 200 ns compared with the conventional driving waveform.
Design and Performance Evaluation of the Secure Transmission Module for Three-dimensional Medical Image System based on Web PACS
Kim, Jungchae ; Yoo, Sun Kook ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 179~186
DOI : 10.5573/ieek.2013.50.3.179
PACS is a medical system for digital medical images, and PACS expand to web-based service using public network, DICOM files should be protected from the man-in-the-middle attack because they have personal medical record. To solve the problem, we designed flexible secure transmission system using IPSec and adopted to a web-based three-dimensional medical image system. And next, we performed the performance evaluation changing integrity and encryption algorithm using DICOM volume dataset. At that time, combinations of the algorithm was `DES-MD5`, `DES-SHA1`, `3DES-MD5`, and `3DES-SHA1, and the experiment was performed on our test-bed. In experimental result, the overall performance was affected by encryption algorithms than integrity algorithms, DES was approximately 50% of throughput degradation and 3DES was about to 65% of throughput degradation. Also when DICOM volume dataset was transmitted using secure transmission system, the network performance degradation had shown because of increased packet overhead. As a result, server and network performance degradation occurs for secure transmission system by ensuring the secure exchange of messages. Thus, if the secure transmission system adopted to the medical images that should be protected, it could solve server performance gradation and compose secure web PACS.
A study on Evaluation Methods for Safety and Performance of Electrical Stimulations for Home Use
Kim, San ; Jang, Moo-Young ; Hwang, Yoon Su ; Lee, Ki-Hun ; Hur, Chan-Hoi ; Hong, Choongman ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 187~202
DOI : 10.5573/ieek.2013.50.3.187
The electronic medical device industry and the relevant market have been greatly expanded owing to various factors, such as the advent of the aged society and the spread of the desire for well-being in developed countries, and rapid development of China, India and other emerging markets. The electrical stimulator is one of electronic medical devices most commonly used in homes. The electrical stimulator is widely used for pain relief, rehabilitation, muscle conditioning and others. Since it is mainly used in homes, it is very important to assure the safety and performance for protection of users. However, there is no guideline on evaluation of safety and performance of such electrical stimulator for home use. In this study, various local and foreign references were reviewed to develop the internationally harmonized procedures for safety and performance evaluation of the electrical stimulator and test items, specifications and methods are proposed. In addition, such proposed test items were validated to decide the internationally harmonized tests for safety and performance evaluation. This study will contribute to improvement of quality and safety of electrical stimulators for home use and help the Korean medical device industry have the international competitiveness.
Design, Implementation, and Control of Two Arms of a Service Robot for Floor Tasks
Bae, Yeong Geol ; Jung, Seul ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 203~211
DOI : 10.5573/ieek.2013.50.3.203
This paper presents the implementation and control of two arms of an indoor service robot for floor tasks. The robot arms are designed to have 6 degrees-of-freedom (DOF), but actually built to have 5 DOF. Forward and inverse kinematics of two arms are analyzed and simulated to confirm the kinematic analysis. Two arms are actually controlled based on the inverse kinematics. The right and left arms are separately controlled to follow different trajectories in order to make sure the functionality of both arms. Experimental studies are conducted to confirm the kinematic analysis and proper operation of two arms.
SAR Image Processing Using SVD-Pseudo Spectrum Technique
Kim, Binhee ; Kong, Seung-Hyun ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 212~218
DOI : 10.5573/ieek.2013.50.3.212
This paper presents an SVD(Singular Value Decomposition)-Pseudo Spectrum method for SAR (Synthetic Aperture Radar) imaging. The purpose of this work is to improve resolution and target separability of SAR images. This paper proposes SVD-Pseudo Spectrum method whose advantages are noise robustness, reduction of sidelobes and high resolution of spectral estimation. SVD-Pseudo Spectrum method uses Hankel Matrix of signal components and SVD (Singular Value Decomposition) method. In this paper, it is demonstrated that the SVD-Pseudo Spectrum method shows better performance than the matched filtering method and the conventional super-resolution based multiple signal classification (MUSIC) method in SAR image processing. The targets to be separated are modeled, and this modeled data is used to demonstrate the performance of algorithms.
A Study on the Synthetic Aperture Radar System Motion Compensation Technique
Kang, Eun-Kyun ; Ra, Keuk-Hwan ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 221~229
DOI : 10.5573/ieek.2013.50.3.221
In this paper, the image formation by the motion compensation technique for Synthetic Aperture Radar system(SAR) were realized through the computer simulation. The motion compensation technique performed image data with the range compression, the compensation procedure, the azimuth compensation and the noise elimination procedure. The range compression procedure transform the SAR raw data into the frequency domain and correlate with the range reference function and then inversely transform into the time domain. The compensation procedure contain the aircraft fluctuations compensation and the radar image degrading effect elimination procedure which was caused by image formation algorithm itself. The aircraft fluctuations compensation procedure perform the first stage which correct the phase angle and the second stage which calculate the Doppler frequency and determine the coordinate of the received signal. The radar image degrading effect elimination procedure also perform range migration compensation and the image defocussing effect compensation. The azimuth compression procedure transform the compensation data to the frequency domain and correlate with the azimuth reference function. The azimuth correlated data are inversely transformed to the time domain which is called SAR image data. When the above procedure were completed, the image data contains the received signals mixed with noise. The threshold technique was applied to elimination the noise from the mixed image data.
Numerical Calculation for Input Impedance of a Conductor Located in the Loss Media
Ahn, Chang-Hwan ;
Journal of the Institute of Electronics and Information Engineers, volume 50, issue 3, 2013, Pages 230~236
DOI : 10.5573/ieek.2013.50.3.230
This paper presents the numerical calculation for input impedance of a conductor located in the loss media by using the program with MATLAB. The input impedances of the conductor were numerically calculated with the moment of method. To increase an accuracy of results, the Galerkin`s method which both the basic function and the weight function are the triangle function was applied. And by applying the modified image method, image sources of the conductor located in air were considered. According to the comparison between the current distributions at the conductor which were calculated with the MATLAB program and the NEC program, the reliability of the self-made program with MATLAB was obtained. In case of the conductor located in soil, which length are 1 m and 2 m, the input impedance were simulated as a function of both a conductivity and a frequency. Finally, input impedances and phases of the conductor located in soil were measured, and those results were compared with simulated results which calculated under the same conditions.