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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of IKEEE
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Journal DOI :
Institude of Korean Electrical and Electronics Engineers
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Volume & Issues
Volume 16, Issue 4 - Dec 2012
Volume 16, Issue 3 - Sep 2012
Volume 16, Issue 2 - Jun 2012
Volume 16, Issue 1 - Mar 2012
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Design and Implementation of a MIMO Antenna for LTE700/2300/2500/PCS/Wibro/Bluetooth/Wimax Mobile Handset
Hong, Yeon-Chan ; Lee, Seong-Ha ; Yang, Woon-Geun ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 159~166
DOI : 10.7471/ikeee.2012.16.3.159
In this paper, we designed and implemented the MIMO (Multiple-Input Multiple-Output) antenna for the mobile handset that could be used for multiple services. Simulation results were obtained using SEMCAD X by SPEAG based on the FDTD (Finite Difference Time Domain) Method which showed that S11 values were less than -6 dB (VSWR < 3) for LTE (Long Term Evolution) 700/2300/2500, K-PCS (Korea-Personal Communication Service : 1,750 ~ 1,870 MHz), US-PCS (US-Personal Communication Service : 1,850 ~ 1,990 MHz), Wibro (2,300 ~ 2,390 MHz), Bluetooth (2,400 ~ 2,483 MHz), and US-WiMAX (US-World interoperability for Microwave Access: 2,400 ~ 2,590 MHz) frequency bands. Measured results of the fabricated antenna also showed that it could be used for LTE 700/2300/2500, K-PCS, US-PCS, Wibro, Bluetooth, and US-WiMAX. services.
Research on the Influence of Absorbing Sheet for Electrical Performance of NFC Antenna
Jung, Young-Bae ; Lee, Seung-Ho ; Oh, Hyeok-Jun ; Jeon, Tae-Joon ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 167~172
DOI : 10.7471/ikeee.2012.16.3.167
In this paper, we analyze the antenna performance variation by the ferrite absorbers which are widely used to optimize the antenna performance in near-field communications(NFC). Using various commercial absorbers, it was confirmed that the absorbers affect the electric performance of NFC antenna, and how to experimentally analyze the electrical influence of the absorbers in NFC antennas is proposed.
Conformal Horn Antenna for Circular Polarization using Planar-type Radiator
Jung, Young-Bae ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 173~176
DOI : 10.7471/ikeee.2012.16.3.173
This paper introduces a novel horn antenna for circular polarization using a planar-type radiator. This antenna can be divided to two parts, microstrip antenna and square horn. The microstrip antenna has the role of feeder and polarizer of the horn antenna, and it is designed to stacked type having metal spacer for high gain, high isolation and wideband characteristic. Using the proposed antenna structure, the horn antenna needs not additional structure such as feeder and polarizer, and the size of it can be considerably reduced. The horn antenna has typical gain of 8dBi and 3-dB axial-ratio bandwidth around 4.9%.This antenna can widely used for various antenna system for mobile and satellite communication using circular polarization expecially in high frequency band.
Thermal Compensation Circuit with Improved Compensation Characteristic for Power Amplifier
Jung, Young-Bae ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 177~181
DOI : 10.7471/ikeee.2012.16.3.177
This paper introduces a thermal compensation circuit with improved compensation characteristic for amplifiers to provide stable output power regardless environmental temperature. The proposed thermal compensation circuit is composed of two branchline couplers having two diodes between them. And, the thermistor whose resistance varies significantly with temperature inversely and a operational amplifiers, so called as OP-amp, control the diodes in the compensations circuit to realize more effective thermal compendation characteristic compared with conventional circuit.
Histogram of Gradient based Efficient Image Quality Assessment
No, Se-Yong ; Ahn, Sang-Woo ; Chong, Jong-Wha ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 182~188
DOI : 10.7471/ikeee.2012.16.3.182
Here we propose an image quality assessment (IQA) based on histogram of oriented gradients (HOG). This method makes use of the characteristic that the histogram of gradient image describes the state of input image. In the proposed method, the image quality is derived by the slope of the HOG obtained from the target image. The line representing the HOG is measured by a random sample consensus (RANSAC) on the HOG. Simulation results based on the LIVE image quality assessment database suggest that the proposed method aligns better with how the human visual system perceives image quality than several state-of-the-art IQAs.
Frequency Domain Error Compensation of RVDT Sensor using FFT
Lee, Chang-Su ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 189~196
DOI : 10.7471/ikeee.2012.16.3.189
This paper proposes new phase error compensation method of RVDT encoder in the FFT domain. Phase errors are measured with a small combination of compensation resistors and the changes of first order coefficients of FFT for each resistor are obtained. It is found that the coefficient change is inversely proportional to the inserted resistor. The proposed method takes less time and the size of the table is smaller than previous time domain approaches. In addition, the location of the compensation resistor can be found through axis transformation of the coefficients. Finally, the peak-to-peak phase error was improved to 0.57 which is two times better than previous one.
Voltage Island Partitioning Based Floorplanning Algorithm
Kim, Jae-Hwan ; Chong, Jong-Wha ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 197~202
DOI : 10.7471/ikeee.2012.16.3.197
As more and more cores are integrated on a single chip, power consumption has become an important problem in system-on-a-chip (SoC) design. Multiple supply voltage (MSV) design is one of popular solutions to reduce power consumption. We propose a new method that determines voltage level of cores before floorplanning stage. Besides, our algorithm includes a new approach to optimize wire length and the number of level shifters without any significant decrease of power saving. In simulation, we achieved 40-52% power saving and a considerable improvement in runtime, whereas an increase in wire length and area is less than 8%.
PWM CMOS DC-DC Boost Converter with Adaptive Dead-Time Control
Hwang, In-Ho ; Yoon, Eun-Jung ; Park, Jong-Tae ; Yu, Chong-Gun ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 203~210
DOI : 10.7471/ikeee.2012.16.3.203
Since the non-overlapping gate driver used in conventional DC-DC boost converters generates fixed dead-times, the converters suffer from the body-diode conduction loss or the charge-sharing loss. To reduce the efficiency degradation due to these losses, this paper presents a PWM DC-DC boost converter with adaptive dead-time control. The proposed DC-DC boost converter delivering 3.3V output from a 2.5V input is designed with CMOS
technology. It operates at 500kHz and has a maximum power efficiency of 97.3%.
Phase boundary estimation with effective initial guess in electrical impedance tomography
Kim, Bong-Seok ; Kim, Sin ; Kim, Kyung-Youn ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 211~216
DOI : 10.7471/ikeee.2012.16.3.211
In the phase boundary estimation problem, the estimation performance depends on the initial guess. However, there is no information on the number of bubbles and those positions for the initial guess in real flows. Therefore, it is very important to set appropriate initial guesses from prior information. In this paper, in order to set initial guesses for estimating the phase boundaries in two-phase flows, first, unknown resistivity distribution was estimated using the difference reconstruction method. After that, an adaptive threshold value was automatically computed using intermodes method. Based on this value, the number of bubbles and the initial position were determined. The numerical experiments have been performed to evaluate the estimation performance of the proposed method.
Design and Operational Characteristics of 150MW Pulse Power System for High Current Pulse Forming Network
Hwang, Sun-Mook ; Kwon, Hae-Ok ; Kim, Jong-Seo ; Kim, Kwang-Sik ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 217~223
DOI : 10.7471/ikeee.2012.16.3.217
This paper presents design and operational characteristics of 150 MW pulse power system for high current pulse forming network to control trigger time. The system is composed of two capacitor bank modules. Each capacitor bank module consist of a trigger vacuum switch, 9k 33kJ capacitor, an energy dump circuit, a crowbar circuit and a pulse shaping inductor and is connected in parallel. It is controlled by trigger controller to select operational module and determine triggering time. Pspice simulation was conducted about determining parameters of components such as crowbar circuit, capacitor, pulse forming inductor, trigger vacuum switch and predicting results of experiment circuit. The result of the experiment was in good agreement with the result of the simulation. The various current shapes with 300~650 us pulse width is formed by sequential firing time control of capacitor bank module. The maximum current is about 40 kA during simultaneous triggering of two capacitor bank modules. The developed 150 MW pulse power system can be applied to high current pulse power system such as rock fragmentation power sources, Rail gun, Coil gun, nano-powers, high power microwave.
Design of an Energy Harvesting Circuit Using Solar and Vibration Energy with MPPT Control
Yoon, Eun-Jung ; Hwang, In-Ho ; Park, Jong-Tae ; Yu, Chong-Gun ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 224~234
DOI : 10.7471/ikeee.2012.16.3.224
This paper describes an energy harvesting circuit using solar and vibration energy with MPPT(Maximum Power Point Tracking) control for micro sensor nodes. The designed circuit employs MPPT control to harvest maximum power available from a PZT vibration element and an integrated solar cell. The harvested energies are simultaneously combined and stored in a storage capacitor, and then managed and transferred into sensor node by PMU(Power Management Unit). MPPT controls are implemented using the linear relationship between the open-circuit voltage of an energy transducer and its MPP(Maximum Power Point) voltage. The proposed circuit is designed in a CMOS 0.18um technology and its functionality has been verified through extensive simulations. The designed energy harvesting circuit and integrated solar cell occupy
A Study on Humanoid Robot Control Method Using Zigbee Wireless Servo Motor with Sensor Network
Shin, Dae-Seob ; Lee, Hyeong-Cheol ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 235~243
DOI : 10.7471/ikeee.2012.16.3.235
In this study, we developed two legged multi-joint robot by using wireless servo motor that was applied by wireless sensor network technology, which is widely used recently, and performed an experiment of walking method of two legged multi-joint robot. We constructed the star network with servo motors which were used at each joint of two-legged robot. And we designed the robot for operation by transmission of joint control signal from main control system or by transmission of the status of each joint to the main control system, so it operates with continuously checking the status of joints at same time. We developed the humanoid robot by using wireless digital servo motor which is different from existing servo motor control system, and controlled it by transmitting the information of angles and speeds of robot joints to the motor(node) as a feedback through main control system after connecting power and setting up the IDs to each joint. We solved noisy problem generated from wire and wire length to connection point of the control device by construction of the wireless network instead of using existing control method of wiring, and also solved problem of poor real time response to gait motion by controlling the position with continuous transmission of control signals to each joint. And we found that the effective control of robot is able by performing the simulation on walking motion in advance with the developed control algorithm which was downloaded into installed memory. Also we performed the stable walking with two-legged robot by attaching pressure sensor to robot sole. And we examined the robot gait operated by application of calculated algorithm on robot movement to each joint. In this study, we studied the method of controlling robot gait motion by using wireless servo motors and measured the torque applied to each joint, and found that the developed wireless servo motor by ZigBee sensor network offers easier control of two legged robot gait and better circuit configuration of it than the existing wired control system could do.
Low Power On-channel Repeater for Terrestrial DTV Broadcasting Services(I) : Technical Regulations
Kwon, Won-Hyun ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 244~250
DOI : 10.7471/ikeee.2012.16.3.244
In this paper, worldwide standards and regulations on broadcasting services are reviewed to improve the fringe area of terrestrial DTV broadcasting services. Using these results, in-band/out-of-band emission requirements of low power DTV repeater with 10mW/MHz radiating power are proposed, and experimentally evaluated and verified. Using the proposed regulations, compact and cost-effective DTV repeater can be easily implemented to broaden DTV broadcasting coverage and to improve small/medium size DTV fringe areas.
Low Power On-channel Repeater for Terrestrial DTV Broadcasting Services(II) : Implementation and Field Trials
Kwon, Won-Hyun ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 251~257
DOI : 10.7471/ikeee.2012.16.3.251
In this paper, low power on-channel DTV repeater is implemented to improve the fringe area of terrestrial DTV broadcasting services and its effectiveness is verified by field trials. System requirements of on-channel repeater are drive from received signal model and gain transfer model. Implemented on-channel DTV repeater has coverage of about 1km with 10mW/MHz output power. Experimental results show that implemented system can effectively improve small/medium size DTV fringe areas in Korea.
Matching Pursuit Based Sparse Multipath Channel Estimation for Multicarrier Systems
Kim, See-Hyun ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 258~264
DOI : 10.7471/ikeee.2012.16.3.258
Although linear channel estimation for the frequency selective fading channel has been widely deployed, its accuracy depends on the number of pilots to probe the channel. Thus, it is unavoidable to employ large number of pilots to enhance the channel estimation performance, which essentially leads to the degradation of the transmission efficiency. It even does not utilize the sparseness of the multipath channel. In this paper a sparse channel estimation scheme based on the matching pursuit algorithm and a pilot assignment method, which minimizes the coherence, are proposed. The simulation results reveal that the proposed algorithm shows superior channel estimation performance with fewer pilots to the LS based ones.
An Advanced Embedded SRAM Cell with Expanded Read/Write Stability and Leakage Reduction
Chung, Yeon-Bae ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 265~273
DOI : 10.7471/ikeee.2012.16.3.265
Data stability and leakage power dissipation have become a critical issue in scaled SRAM design. In this paper, an advanced 8T SRAM cell improving the read and write stability of data storage elements as well as reducing the leakage current in the idle mode is presented. During the read operation, the bit-cell keeps the noise-vulnerable data `low` node voltage close to the ground level, and thus producing near-ideal voltage transfer characteristics essential for robust read functionality. In the write operation, a negative bias on the cell facilitates to change the contents of the bit. Unlike the conventional 6T cell, there is no conflicting read and write requirement on sizing the transistors. In the standby mode, the built-in stacked device in the 8T cell reduces the leakage current significantly. The 8T SRAM cell implemented in a 130 nm CMOS technology demonstrates almost 100 % higher read stability while bearing 20 % better write-ability at 1.2 V typical condition, and a reduction by 45 % in leakage power consumption compared to the standard 6T cell. The stability enhancement and leakage power reduction provided with the proposed bit-cell are confirmed under process, voltage and temperature variations.
Design of Lighting Control Algorithm for Intelligent LED Lighting System
Hong, Sung-Il ; Lin, Chi-Ho ;
Journal of IKEEE, volume 16, issue 3, 2012, Pages 274~282
DOI : 10.7471/ikeee.2012.16.3.274
In this paper, we propose the design of lighting control algorithm for intelligent LED lighting system. The proposed lighting control algorithm transmitted to MCU through a data bus the environmental information detected from respectively sensor node. The MCU control software was designed to determine the level maintained to depending on the set control method by comparing the results that calculated the dimming level using a signal value. Also, it was designed to be lighting by cross-performed periodically the rotation and reverse method by created fully symmetrical pattern using the control algorithm to LED lighting device. In this paper, the proposed lighting control algorithm improved the reliability of the data sent by designed the system that can be controlled lighting to stable, and it was maintained the event delivery ratio of 91%. Also, the lighting device was decreased the luminous intensity of 32%, the power consumption of 49%, and heat generation of 32%. As a result, it were could be improved the energy efficiency that the life-cycle of LED has been increased 50%.