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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of IKEEE
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Institude of Korean Electrical and Electronics Engineers
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Volume & Issues
Volume 10, Issue 2 - Dec 2006
Volume 10, Issue 1 - Jul 2006
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Fabrication and Measurement of a Compact Half-bowtie-shaped Meander Microstrip Patch Antenna for the 5-GHz Band
An, Gyoo-Chul ; Kim, Heung-Su ; Lee, Sang-Mok ; Yun, Chung-Han ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 1~9
This paper presents the characteristics of a half-bowtie-shaped meander-type antenna for the 5-GHz band. Its design is based on a modified meander line width and bowtie shape with coaxial feeding. Its maximum measured impedance bandwidth (-10 dB below) is approximately 1.055 GHz (5.01-6.065 GHz) or 19.05%. Radiation patterns at different frequencies are presented. The measured gain was 2.26-8.86 dBi.
3.125Gbps Reference-less Clock and Data Recovery using 4X Oversampling
Jang, Hyung-Wook ; Kang, Jin-Ku ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 10~15
In this paper, a clock and data recovery (CDR) circuit for a serial link with a half rate 4x oversampling phase and frequency detector structure without a reference clock is described. The phase detector (PD) and frequency detector (FD)are designed by 4X oversampling method. The PD, which uses bang-bang method, finds the phase error by generating four up/down signal and the FD, which uses the rotational method, finds the frequency error by generating up/down signal made by the PD output. And the six signals of the PD and the FD control an amount of current that flows through the charge pump. The VCO composed of four differential buffer stages generates eight differential clocks. Proposed circuit is designed using the 0.18um CMOS technology and operating voltage is 1.8V. With a 4X oversampling PD and FD technique, tracking range of 24% at 3.125Gbps is achieved.
Multiphase PLL using a Vernier Delay VCO
Sung, Jae-Gyu ; Kango, Jin-Ku ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 16~21
This paper shows a vernier delay technique for generating precise multiphase clocks using PLL structure. The proposed technique can achieve the finer timing resolution less than the gate delay of the delay chain in VCO. Using this technique, 62.5ps of timing resolution can be achieved if the reference clock rate is set at 1GHz using 0.18um CMOS technology. Jitter of 14ps peak-to-peak was measured.
SDRAM Fast Accession By DMA (Direct Memory Access)
Kim, Jin-Wan ; Cho, Hyun-Mook ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 22~29
In this paper, we present the efficient way of SDRAM accessing through the DMA(Direct Memory Access) when a microprocessor and peripheral blocks are sharing a SDRAM. The microprocessor is able to access a memory through the AMBA which is the system bus provided by ARM Corporation and DMAs are able to access a memory through their own bus. Peripheral block's reading and writing on the SDRAM memory are realized by the intermediate DMA in order to minimize times of access and addressing the memory. While the microprocessor doesn‘t access to the SDRAM aproaching other registers or occurring a hit signal for fetching program or data, the DMAs may read/write the data in the SDRAM without an interference of the AMBA. This way increases the efficient of the system and performance is more by 16.8%.
A Study on TCP Performance Enhancements in Wireless Networks
Park, Do-Yong ; Kim, Young-Beom ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 30~39
The TCP protocol can provide some reliability using sliding window mechanism for data transmission, flow control, and congestion control. However, TCP has some limitations in that it has basically been designed solely for wired communication environments. If traditional TCP protocol is used also in wireless networks, the end-to-end data transmission performance degrades dramatically due to frequent packet losses caused by transmission errors and hand-offs. While there have been some research efforts on TCP enhancements considering the mobility of wireless communication devices, in this paper we propose a new method to improve the TCP performance by combining the Snoop and the Freeze-TCP methods. In the proposed scheme, the TCP end-to-end semantics is maintained and no changes of existing protocols in sending systems or in routers are required. It has the advantage of simple implementation because TCP code changes are limited to mobile devices for applying the Freeze-TCP and it requires only to add Snoop modules in base stations. Accordingly, the proposed scheme can operate well in the existing networks. Finally, in this study, we compared the performance of the proposed scheme with traditional TCP, other approaches through simulations using ns-2.
Generation of 3D Building Model by Grouping of 3D Line Segments
Kang, Yon-Uk ; Woo, Dong-Min ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 40~48
This paper presents a new rooftop surface estimation method from 3D line segments. 3D rooftop surface estimation is based on the hierarchical grouping and initiated by 3D line merging for the disconnected 3D line segments. Merged 3D lines are applied to the detection of rooftop by surface estimating technique. To estimate surfaces we detect L-corner and T-corner points, and find fixed reliable junction points. The hypothesis of the possible rooftop surfaces are estimated as polygonal surfaces by these fixed junction points and building's rooftop models are generated by testing the possible surfaces in terms of assumptions of building surface properties. We carried out experiments by synthetic images on Avenches data set and the experimental results showed that we could reliably build 3D model with 3D surfaces, errors of which came up with 0.4 - 1.3 meter, 2.5 times more accurate than the elevation date from the conventional area-based stereo.
A design of the SMBC Platform using the Fit FA-Finder
Park, Nho-Kyung ; Han, Sung-Ho ; Seo, Sang-Jin ; Jin, Hyun-Joon ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 49~54
Recently, e-mail has become an important way of communications in IT societies, but it creates various social problems due to increase of spam mails. Even though many organizations and cooperation have been trying researches to develop spam mail blocking technologies, a lot of cost and system complexities are required because of varieties of spam blocking technologies. In this paper, we designed of the SMBC(Spam Mail Blocking Center) using the Fit FA(Filtering Algorithm) Finder. Fit-FA Finder that search and applises spam mail filtering algorithm of the most suitable confrontation according to type of spam mail. The system of spam mail filtering is decided performance of the system by procedure that spam filter is used. Go through designed Fit-FA Finder and reduced unnecessary filtering process and processing time and load than appointment order filter application way of existent spam mail interception system.
A Study on Wearable Emergency Medical Alarm System
Kim, Dong-Wan ; Beack, Seung-Hwa ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 55~61
In modern society, development of medical technology has extended the human life span. However, it has also caused some side-effects. Mostly old people who live alone are not available the medical service quickly when they are in emergency situations. Moreover heart related diseases as well are rapidly increasing with aging. This study proposes the emergency medical alarm system. This system measures the physiological signals such as ECG(electrocardiogram), temperature, and motion data, analyzes those data automatically, and sends the urgent message to the Emergency Medical Center and to their family. There are two main parts in the system. In the first part, physiological data acquisition part, the troublesome addition and deletion of body signals on existing proposed systems have been supplemented, which led to the modulized production by means of ECG sensor module, temperature sensor module, acceleration sensor module. The other part is mobile unit, which includes signal processing and transmission functions. And bluetooth allows two parts to communicate with each other. Data that are processed in the mobile unit are stored in the PC database through the WLAN using TCP/IP protocol.
자력복구 적응 채널등화기를 위한 Run and Go 알고리즘
Chung, Won-Zoo ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 62~68
In this paper, we propose an adaptation strategy for blind equalizers, which combines a blind algorithm based on high order statistics and the decision directed LMS algorithm. In contrast to 'Stop-and-Go' algorithm, where adaptation is stopped for unreliable signals, the proposed algorithm applies high order statistics (HOS) blind algorithm to the unreliable signals and applies DD-LMS for the reliable signals. The proposed algorithm, named 'Run-and-Go' algorithm, inherits minimum MSE performance of DD-LMS and acquisition ability of blind algorithms. Furthermore, by updating the reliable signal region according to signal quality in each iteration, the convergence speed and acquisition ability is further improved.
격자코드 변조 시스템에서 DFE의 심볼판정 알고리즘 제안
Chung, Won-Zoo ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 69~74
In this paper, we present symbol detection methods for decision feedback equalizers (DFE) in trellis coded modulation systems. The proposed symbol detectors improve symbol error rate (SER) by exploiting the coding structure of trellis coded modulation (TCM). For example, for 8-PAM signals the achieved SER with the proposed detection scheme is improved to
of the conventional symbol-by-symbol detector under AWGN channel at 20dB SNR. This SER improvements mitigate error propagation of DFE.and produces significant over-all SER improvement for under multipath channels (for example, from 0.26 to 0.01 and 0.005 under a severe multipath channel 20dB SNR as shown in the simulation result of this paper).
Performace Evaluation of Global MANET adapted to Internet Access solution
Jung, Chan-Hyuk ; Oh, Se-Duk ; Kim, Hyun-Wook ; Lee, Kwang-Bae ; Yu, Choung-Ryoul ; Mun, Tae-Su ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 75~86
The MANET that can make autonomous distributed Network with Routing function has many differences than past wireless communication. For upcoming ALL-IP environment, MANET device should be connected with wired Internet Network and MANET is required to have a gateway to bridge two different networks to share information from any place. In this paper, Using the GMAHN Algorithm proposed Proactive, Reactive, Hybrid method that provides Inteface between Wired Internet network and MANET, we learned each method's the advantage and disadvantage through the various network environments. And also, we presented the optimization method of Hybrid combined Proactive with Reactive.
Analyses of the Effect of Inserting Border Lines between Adjacent Color Regions on Detecting Boundaries
Yoo, Hyeon-Joong ; Kim, Woo-Sung ; Jang, Young-Beom ;
Journal of IKEEE, volume 10, issue 1, 2006, Pages 87~95
This paper presents the analyses of the effect of inserting border lines between different color regions on edge detection in color codes, and is not intended to present any new algorithm for color-code recognition. With its role to complement the RFID (radio frequency identification) and the wide and fast spread of digital cameras, an interest on color codes is fast increasing. However, the severe distortion of colors in obtained images prohibits color codes from expanding their applications. To reduce the effect of color distortion it is desirable to process the whole pixels in each color region statistically, instead of relying on some pixels sampled from the region. This requires segmentation, and the segmentation usually requires edge detection. To help detect edges not disconnected, we inserted border lines of the width of two pixels between adjacent color regions. Two colors were used for the border lines: one consisting of white pixels, and the other black pixels. The edge detection was performed on images with either of the two kinds of border lines inserted, and the results were compared to results without inserted border lines. We found that inserting black border lines degraded edge detection by causing zipper effect while inserting white border lines improved it compared to the cases without inserted border lines.