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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 12, Issue 4 - Dec 2008
Volume 12, Issue 3 - Sep 2008
Volume 12, Issue 2 - Jun 2008
Volume 12, Issue 1 - Mar 2008
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Antenna Efficiency Variation by the Influence of Human Body
Lee, Yong-Joo ; Han, Jun-Hee ; Yang, Woon-Geun ;
Journal of IKEEE, volume 12, issue 4, 2008, Pages 185~195
In this paper, PIFA(Planar Inverted F Antenna) which operates in PCS(Personal Communication System) band is designed and characteristics are investigated. Designed PIFA was installed in three types of handsets, folder, bar, slide, and the performance was evaluated. Head and hand phantom were added to make the most similar environment to real condition of mobile phone use, and influences on antenna performance were analyzed. The simulation results confirm radiation patterns are greatly changed and antenna efficiency is decreased by the effect of human body. Performance variation of the mobile handset antenna was observed as changing the angle between mobile handset and head phantom from
to confirm the variation caused by the relative position of mobile handset and head phantom. Directivity was decreased gradually as the antenna goes away from head phantom, and showed the trend of increasing efficiency. But in the case of bar type, where the position of antenna is relatively close to head phantom, that trend didn't show. It was confirmed that the shape of handset has a great effect on the performance.
QoS Fairness in Multimedia Service using Wireless LAN
Jin, Hyun-Joon ; Park, Nho-Kyung ;
Journal of IKEEE, volume 12, issue 4, 2008, Pages 196~203
The IEEE 802.11e working group has announced a new distributed MAC(Medium Access Control) called EDCA(Enhanced Distributed Channel Access) to provide service differentiation among classified traffics. In comparison with the 802.11 legacy MAC, the EDCA provides QoS mechanism by differentiated channel access which is called AC(Access Category) to the frames with different priorities. In multimedia applications, however, the EDCA has some difficulties to achieve QoS throughput because of using fixed AC parameters and never considers overall throughputs, i.e. fairness, for classified services. In this paper, AC parameter control technique is proposed to achieve overall QoS throughputs with differentiated services. The proposed technique controls AC parameters dynamically in real time. Simulation is used to verify the technique and the simulation shows that QoS fairness is improved by 13% in throughput deviation in multimedia environments including voice, video and data service.
A Study on the Relation between Respiration and EEG in Stable State
Kim, Young-Sear ; Min, Hong-Ki ;
Journal of IKEEE, volume 12, issue 4, 2008, Pages 204~210
Generally, among the EEG signal, alpha wave is said to be strongly appeared in stable state and beta wave in active state. And in oriental medicine, it is said that relative long and regular respiration shows stable state rather than short and irregular respiration. In this paper, we tried to find out relation between respiration and EEG in stable state using quantitative parameters such as stable state ratio and equivalent ratio of respiration which was defined to indicate the degree of stable state quantitatively. And we verified our proposal by the real experiment for 20 persons.
Design of a Low-Power MOS Current-Mode Logic Parallel Multiplier
Kim, Jeong-Beom ;
Journal of IKEEE, volume 12, issue 4, 2008, Pages 211~216
This paper proposes an 8
8 bit parallel multiplier using MOS current-mode logic (MCML) circuit for low power consumption. The proposed circuit has a structure of low-power MOS current-mode logic circuit with sleep-transistor to reduce the leakage current. The sleep-transistor is used to PMOS transistor to minimize the leakage current. Comparing with the conventional MOS current-model logic circuit, the circuit achieves the reduction of the power consumption in sleep mode by 1/50. The designed multiplier is achieved to reduce the power consumption by 10.5% and the power-delay-product by 11.6% compared with the conventional MOS current-model logic circuit. This circuit is designed with Samsung 0.35
standard CMOS process. The validity and effectiveness are verified through the HSPICE simulation.
Semantic Correspondence of Database Schema from Heterogeneous Databases using Self-Organizing Map
Dumlao, Menchita F. ; Oh, Byung-Joo ;
Journal of IKEEE, volume 12, issue 4, 2008, Pages 217~224
This paper provides a framework for semantic correspondence of heterogeneous databases using self- organizing map. It solves the problem of overlapping between different databases due to their different schemas. Clustering technique using self-organizing maps (SOM) is tested and evaluated to assess its performance when using different kinds of data. Preprocessing of database is performed prior to clustering using edit distance algorithm, principal component analysis (PCA), and normalization function to identify the features necessary for clustering.
A study on characteristics of High Efficiency and Wideband Microstrip Band Pass Filter for Wireless Data Communication
Lee, Young-Hun ; Song, Sung-Hae ; Park, Won-Woo ; Lee, Sang-Jae ;
Journal of IKEEE, volume 12, issue 4, 2008, Pages 225~233
This paper presents a compact, low insertion loss, sharp rejection and wide band microstrip band pass filter that is composed rectangular loop resonator and step-impedance-open-stub(SIOS) for wireless data communication. The SIOS can be reduce length about 30% more than general 0.25
stub. And stubs can have the advantage of tuning impedance magnitude. In order to demonstrate agrement of this paper prove, the optimized wide band pass filters are realized and experimented. A transmission line model used to calculate the frequency response of the new filters shows good agreement with measurements. The filter with perturbation stubs has four poles at rejection band, the poles are excited 3.610GHz, 4.265GHz at low frequency band, 8.494GHz, 9.056GHz at high frequency band. And the filter has 3dB fractional bandwidth of 57%(3.695GHz), an insertion loss of better than 0.37dB from 4.549GHz to 8.244GHz, and two rejection of greater than 30dB within 237MHz(4.312GHz
4.549GHz) at low frequency band, 234MHz(8.244GHz-8.491GHz) at high frequency band.
A Stable 40 GHz Pulse Train Generation by Pulse Repetition-Frequency Quadruplication Using a Fiber Fabry-Perot Interferometer
Ruan, Wan-Yong ; Park, Jae-Hyun ; Seo, Dong-Sun ;
Journal of IKEEE, volume 12, issue 4, 2008, Pages 234~238
We demonstrate a simple method to generate a stable 40 GHz pulse train at 1550 nm by spectral filtering of a 10 GHz mode.locked pulse source using a fiber Fabry-Perot interferometer (FFPI). A high finesse FFPI with a 40 GHz free spectral range blocks successfully unwanted spectral components of a 10 GHz pulse source and passes only 40 GHz spaced spectral lines ensuring pulse repetition-frequency quadruplication of the input pulses.
Design of the power generator system for photovoltaic modules
Park, Sung-Joon ;
Journal of IKEEE, volume 12, issue 4, 2008, Pages 239~245
In this paper, a dc-dc power converter scheme with the FPGA based technology is proposed to apply for solar power system which has many features such as the good waveform, high efficiency, low switching losses, and low acoustic noises. The circuit configuration is designed by the conventional control type converter circuit using the isolated dc power supply. This new scheme can be more widely used for industrial power conversion system and many other purposes. Also, I proposed an efficient photovoltaic power interface circuit incorporated with a FPGA based DC-DC converter and a sine-pwm control method full-bridge inverter. The FPGA based DC-DC converter operates at high switching frequency to make the output current a sine wave, whereas the full-bridge inverter operates at low switching frequency which is determined by the ac frequency. As a result, we can get a 1.72% low THD in present state using linear control method. Moreover, we can use stepping control method, we can obtain the switching losses by Sp measured as 0.53W. This paper presents the design of a single-phase photovoltaic inverter model and the simulation of its performance.
A Design of a Shader Processor based on a dual-phase pipeline architecture
Jeong, Hyung-Ki ; Nam, Ki-Hun ; Lee, Gwang-Yeob ;
Journal of IKEEE, volume 12, issue 4, 2008, Pages 246~254
This paper represents a design of a 4 way SIMD processor with multi-thread and dual phase instruction pipeline. 8 threads can be performing in round-robin order, so any hazards can’t occur. The dual phase pipeline makes a pipeline operate as two pipelines, and it can fetch maximum 4 unit instructions at once. This variable length instruction set divide into first phase and second phase instructions, and with this function, complex branch and addressing can be executed at one clock cycle. This processor reduces the code size to quarter, pull out the doubled performance improvement than normal SIMD architecture.
Analysis of the electrical characteristics of the novel IGBT with additional nMOS
Shin, Samuell ; Son, Jung-Man ; Park, Tea-Ryoung ; Koo, Yong-Seo ;
Journal of IKEEE, volume 12, issue 4, 2008, Pages 255~262
In this paper, we proposed the novel IGBT with an additional n-type MOS structure to achieve the improved trade-off between turn-off and on-state voltage drop(Vce(sat)). These low on-resistance and the fast switching characteristics of the proposed IGBT are caused by an enhanced electron current injection efficiency which is caused by additional n-type MOS structure. In the simulation result, the proposed IGBT has the lower on state voltage of 2.65V and the shorter turn-off time of 4.5us than those of the conventional IGBT(3.33V, 5us).