• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.185-190
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• 2006

The correct estimation of the ionospheric delays is very important for the precise kinematic positioning especially in case of the long baseline. In case of triple frequency system, the ionospheric delays can be estimated from the measurements, but, in case of dual frequency system, the situation is not so simple. The precision of those supplied by the external information source such as IONEX is not sufficient. The high frequency component is neglected, and the precision of the low frequency component is not sufficient for the long baseline positioning. On the other hand, the high frequency component can be estimated from the phase range measurements. If the low frequency components are estimated by using the external information source or pseudo range measurements, a more reasonable estimation of the ionospheric delays may be possible. It has already been discussed by the author that the estimation of the low frequency components by using the external information source is not sufficient but fairly effective. The estimation using the pseudo range measurements is discussed in the present paper. The accuracy is not sufficient at present because of the errors in the pseudo range measurements. It is clarified that the bias errors in the pseudo range measurements are responsible for the poor accuracy of the ionospheric delays. However, if the accuracy of the pseudo range measurements is improved in future, the method would become very promising.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.329-336
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• 2007

For scaling of the gradient of misfit function, we develop a new pseudo-Hessian matrix constructed by combining amplitude field and pseudo-Hessian matrix. Since pseudo- Hessian matrix neglects the calculation of the zero-lag auto-correlation of impulse responses in the approximate Hessian matrix, the pseudo-Hessian matrix has a limitation to scale the gradient of misfit function compared to the approximate Hessian matrix. To validate the new pseudo- Hessian matrix, we perform frequency-domain elastic full waveform inversion using this Hessian matrix. By synthetic experiments, we show that the new pseudo-Hessian matrix can give better convergence to the true model than the old one does. Furthermore, since the amplitude fields are intrinsically obtained in forward modeling procedure, we do not have to pay any extra cost to compute the new pseudo-Hessian. We think that the new pseudo-Hessian matrix can be used as an alternative of the approximate Hessian matrix of the Gauss-Newton method.

• Korean Journal of Cognitive Science
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• v.35 no.2
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• pp.97-112
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• 2024

This study investigated how syllable-level variables such as syllable frequency, syllable (i.e. vowel) type, presence of final consonants (i.e. batchim) and syllable position influence naming of both words and pseudo-words. The results of the linear mixed-effects model analysis showed that, for words, naming time decreased as the frequency of the first syllable increased, and when the first syllable had a final consonant. Additionally, words were named more accurately when they had vertical vowels compared to horizontal vowels. For pseudo-words, naming time decreased and accuracy rate increased as the frequency of the first or the second syllable increased. Furthermore, pseudo-words were named more accurately when they had vertical vowels compared to horizontal vowels. These results suggest that while the frequency of the second syllable had differential effects between words and pseudo-words, the frequency of the first syllable and the syllable type had consistent effects for both words and pseudo-words. The implications of this study were discussed concerning visual word recognition processing.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.11
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• pp.547-552
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• 2005

This paper describes a pseudo-random carrier PW technique for the power converters. The proposed method generates a new pseudo-random carrier by randomly composing a carrier with fixed frequency and a carrier with opposition phase. To confirm the validity of the proposed method, a single-phase multi-level inverter was implemented and tested. The experimental results show that the output voltage and current harmonics spectra of an inverter have broadening effect of harmonics, as only simple composition of fixed frequency carries.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.64-70
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• 2008

In case that conventional PRC(Pseudo-Randomized Frequency Carrier) modulation scheme is applied to a three-phase HBML(H-Bridge Multi-Level Inverter), the dominant harmonics spectra appear at twice switching frequency. In this paper, the dominant harmonics spectra spreading effect of the conventional PRC scheme was improved by using three stage MUXs(Multiplexers) and two triangular carriers with fixed frequency which has mutual relation of the twice frequency. To confirm the validity of the improved PRC scheme, the experiment were performed on a 1.5[kw] three-phase HBML based induction motor drives. And, the harmonics spectra of the conventional and improved PRC schemes are compared and discussed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.6
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• pp.84-90
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• 2011

In this paper, a dual-band pseudo-combline narrow bandpass filter is proposed. The proposed bandpass filter adopts the open resonant stubs and the proposed bandpass filter can be used for ITS(Intelligent Transport System) and X-band satellite systems application. The proposed bandpass filter has the insertion and return losses of 1.72 dB and 15.5 dB at the bandwidth of 3.6 % and center frequency of 5.8 GHz, respectively. Also, the second operating frequency band for insertion and return losses are 1.92 dB and 16.3 dB at the bandwidth of 3% and center frequency of 8.5 GHz, respectively.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.8
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• pp.697-702
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• 2001

The ring laser gyro(RLG) has been used extensively in strapdown inertial navigation system(SDINS) because of the apparent of having wide dynamic range, digital output and high accuracy. The dithered RLG system has dynamic motion at sensor level, caused by the dithering motion to overcome the lock-in threshold. In this case, an attitude error is produced by not only the true coning of the vehicle motion but also the pseudo coning of the sensor motion. This paper describes the definition of the multi-frequency coning motion and its noncommutativity error to reject the pseudo coning error produced by the sensor motion such as the dithered RLG. The simulation results are presented to minimize the multi-frequency coning error.

• Korean Journal of Cognitive Science
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• v.34 no.4
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• pp.277-297
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• 2023

This study attempted to find out how lexical decision of two-syllable words or pseudo-words is affected by syllabic information, such as syllable frequency, syllable (i.e. vowel) type, and presence of final consonant (i.e. batchim), through the analysis of the Korean Lexicon Project Database (KLP-DB). Hierarchical regression of RT data showed that lexical decision of words was influenced by the frequency of the first syllable, the syllable type of the first and second syllables, batchim for the first and second syllables, and also by the interaction of the two syllable types and the interaction of syllable frequency and batchim of the second syllable. For pseudo-words lexical decision was influenced by the frequency of the first and second syllables, syllable type of the first syllable, and batchim for the first and second syllables, and also by the interaction of the two syllable frequencies, the interaction of the two syllable types, and the interaction of syllable frequency and batchim of the first syllable. Word frequency had a strong effect on lexical decision of words, while syllabic information had a stable effect on the lexical decision of pseudo-words. These results indicate that syllabic information should be seriously considered in constructing word and pseudo-word lists and interpreting lexical decision time. Understanding the effect of syllabic information will also contribute to the understanding of word recognition process.

• Journal of the Korea Safety Management & Science
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• v.12 no.1
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• pp.63-69
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• 2010

This study is to find out why drivers used to put pseudo-petroleum in their cars and to fundamentally remove any accidents from the misuse. Questionnaire survey has been made in Gimpo area where many drivers can use it comparatively easily outside of Seoul. And they are analyzed statistically using SPSS 12.0 package program. Correlation factor is shown with 0.683, very high relationship between using frequency and use period of cars. It is shown that important factor to give impact to consumer attitude has been produced as car-using period, education level. The longer the cars have been used, the more pseudo petroleum has been used, it is found.

• The Journal of Internal Korean Medicine
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• v.34 no.4
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• pp.405-411
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• 2013

Objectives : This study was designed to investigate the difference between genuine and pseudo halitosis about qi stagnation and stress. Methods : We recruited 63 halitosis patients who visited the halitosis clinic in the Kyung Hee University Korean Medicine Hospital from June 2012 to August 2013. We classified the halitosis patients into two groups, genuine and pseudo halitosis based on organoleptic assesment (OLT) score and evaluated the severity of self-reported halitosis using visual analog scale (VAS), amount of sulfide compounds using Halimeter, qi stagnation level using qi stagnation questionnaire and stress levels using heart rate variability (HRV) parameters. Results : Comparing the genuine halitosis group and the pseudo halitosis group, there was no significant difference in VAS of halitosis but significant difference in halimeter score. Distribution of qi stagnation and non-qi stagnation groups was significantly different between genuine and pseudo halitosis. Compared to the genuine halitosis group, the pseudo halitosis group showed a significant higher value of low frequency/high frequency ratio (LF/HF ratio). Conclusions : The result of this study suggest that there is significant difference about qi stagnation and stress level between genuine halitosis and pseudo halitosis patients, so when approaching pseudo halitosis patients, we should consider their psychological and emotional status.