• Journal of IKEEE
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• v.10 no.1 s.18
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• pp.69-74
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• 2006

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 $2{\times}10^{-5}$ from $2.5{\times}10^{-2}$ 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).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6C
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• pp.561-569
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• 2003

In this paper, for my linear orthogonal space-time block including the orthogonal space-time codes introduced by Alamouti［1］, Tarokh［14］, and Xia［11］, the exact expression for the pairwise error probability in the slow Rayleigh fading channel is derived in terms of the message symbol distance between two message vectors rather than the codeword symbol distance between two transmitted codeword matrices. Using the one-dimensional component symbol error probability, the exact closed form expressions for the symbol error probability of linear orthogonal space-time codes are derived for QPSK, 16-QAM, 64-QAM, and 256-QAM.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.2
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• pp.55-61
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• 2007

In this paper, we represent the maximum detection probability formulas of symbol synchronization timing at each received delay signal in multipath channel delay profile in the multiplied correlation and difference type correlated symbol synchronization timing detection method. The computer simulation results show that the correlation symbol timing detection method have maximum detection probability at the lead of received delay signal of highest amplitude, but the difference type of correlation symbol timing detection method always have maximum detection probability at the lead of first received delay signal in the multipath channel models. Using this results, we show the BER characteristics difference between the IEEE802.11a OFDM signals which is obtained in case of the symbol synchronization timing is taken at zero error(perfect) timing position and at -1 sample error symbol timing position from perfect timing position in the multipath channel models regardless the length of channel delay spread.

• The Journal of the Korea Contents Association
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• v.7 no.7
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• pp.77-86
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• 2007

These days, universities are establishing new image; UI(University Identity) for them because of rapid change of education environment in 21st century, The objective of UI is expressing university's image externally and unifying members internally. In the process of establishing university's image, Symbol mark plays a key role in differentiating other universities because of its visual effect as well as enhancing self-confidence. In this study, I suggest that symbol mark is an important brand asset in point of differentiation and identification and analyze 36 domestic universities' symbol mark designs. In the way of this analysis, I classified these symbol marks in the aspect of shapes and colors and studied current design along with character of each symbol marks by examining usage of emblem. Therefore this paper will be used as a basic reference to understand domestic universities' symbol mark trend and to establishing differentiating strategy in the future.

• ETRI Journal
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• v.42 no.3
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• pp.324-332
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• 2020

In this paper, a blind symbol timing offset (STO) estimation method is proposed for offset quadrature phase-shift keying (OQPSK) modulated signals, which also works for other linearly modulated signals (LMS) such as binary-PSK, QPSK, 𝜋/4-QPSK, and minimum-shift keying. There are various methods available for blind STO estimation of LMS; however, none work in the case of OQPSK modulated signals. The popular cyclic correlation method fails to estimate STO for OQPSK signals, as the offset present between the in-phase (I) and quadrature (Q) components causes the cyclic peak to disappear at the symbol rate frequency. In the proposed method, a set of close and approximate offsets is used to compensate the offset between the I and Q components of the received OQPSK signal. The STO in the time domain is represented as a phase in the cyclic frequency domain. The STO is therefore calculated by obtaining the phase of the cyclic peak at the symbol rate frequency. The method is validated through extensive theoretical study, simulation, and testbed implementation. The proposed estimation method exhibits robust performance in the presence of unknown carrier phase offset and frequency offset.

• Journal of the Korean Society of Costume
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• v.34
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• pp.121-134
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• 1997

The purpose of this study is to research of cultural symbol on Safavid lampas in Persia. The results are as follows. A significant feature of continuous pat-terns in lampas is the use of the human figure and a signature of designer's name in the Islamic world. Motifs can be identi-fied as Safavid lampas by the style of motifs such as birds leaves trees flowers on a gold or silver namely metal back-groud. the result shows that cultural symbol on Safavid lampas is connected with islamic culture.

• Smart Media Journal
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• v.7 no.2
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• pp.23-33
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• 2018

A musical sheet is read by optical music recognition (OMR) systems that automatically recognize and reconstruct the read data to convert them into a machine-readable format such as XML so that the music can be played. This process, however, is very challenging due to the large variety of musical styles, symbol notation, and other distortions. In this paper, we present a model for the recognition of musical symbols through the use of a mobile application, whereby a camera is used to capture the input image; therefore, additional difficulties arise due to variations of the illumination and distortions. For our proposed model, we first generate a line adjacency graph (LAG) to remove the staff lines and to perform primitive detection. After symbol segmentation using the primitive information, we use a covariance-matching method to estimate the similarity between every symbol and pre-defined templates. This method generates the three hypotheses with the highest scores for likelihood measurement. We also add a global consistency (time measurements) to verify the three hypotheses in accordance with the structure of the musical sheets; one of the three hypotheses is chosen through a final decision. The results of the experiment show that our proposed method leads to promising results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.11
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• pp.645-651
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• 2014

For blind equalization, we propose a method of updating an equalizer, which generates an error from selectively applying a transmitted symbol constellation and that of induced equivalently from the transmitted symbol constellation and updates the equalizer by using this error. The proposed method, by selectively using the symbol constellation effective for improvement of symbol estimation accuracy and that of effective for improvement of error performance, showed that it is possible to improve the error performance at the same time to open the eye diagram of equalizer output quickly. As a criterion applying the symbol constellation, we used the dispersion of symbol points of equalizer output. In addition, to increase the accuracy of updating an equalizer the error was controlled by using current and previous dispersions. By simulation, under multipath channel with additive noise, we verified the equalization performance of the proposed method for 64-QAM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.7
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• pp.545-551
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• 2013

Timing recovery loop composed of the Timing Error Detector(TED), loop filter and resampler is widely used for the timing synchronization in MQASK receivers. Since TED is sensitive to the delay between the symbol period of the signal and sampling period, the output is averaged out when the symbol rate and sampling rate are quite different the recovery loop cannot work at all. This paper presents a sampling frequency discriminator (SRD), which detects the frequency offset of the sampling clock to the symbol clock of the MQASK data transmitted. Employing the SRD, the closed loop timing recovery scheme performs the frequency-aided timing acquisition and achieve the synchronization at extremely high sampling frequency offset, which can be used in variable symbol rate MQASK receivers.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.213-216
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• 2005

The time synchronization method for Multi-band UWB systems is proposed. We analyze the performance in symbol synchronization using a training symbol with two identical halves. The two halves of the training symbol are made identical by transmitting a modulated sequence on the even frequencies, while zeros are used on the odd frequencies.