• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.663-664
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• 2010

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.101-104
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• 2011

본 논문에서는 FOB Key Smart Key System module 간의 원할한 통신을 위한 실차 테스트를 하였으며, 실차 테스트를 위한 데모 모듈레이션 구성은 물론 각 모듈간의 통신상태및 최적의 통신 상태를 위한 3차원 그리드 형태의 실험준비를 하였고 최적의 감도를 얻기위한 수천번의 실차 테스트를 실시하였다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.4
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• pp.401-407
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• 2018

The transmission bandwidth of shorted-monopole antenna in the frequency range of LF and MF was analyzed and the transmission mode considering the permissible data rate dependant on the transmission bandwidth was analyzed in this paper. Based on the required ERP, the output power of transmitter was deduced by considering the antenna efficiency. The analyses are for DGPS and time information transmission system in the frequency range of 283.5kHz and 65kHz respectively. The transmission antenna was modeled as TLM antenna that designed in the limited antenna site. The antenna equivalent circuit and antenna bandwidth were deduced based on the simulation analysis of antenna characteristics. The analyzed antenna bandwidth was compared with the simulated antenna bandwidth. Also the transmission mode for transmitter of LF and MF was proposed by considering the antenna bandwidth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1985-1992
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• 2011

PE(Passive Entry) is an automotive technology which allows a driver to lock and unlock door of vehicle without using smart key buttons personally. PG(Pssive Go) is an automotive technology which offers the ability to start and stop the engine when there is a driver in vehicle with smart key. When these two functions are unified, we call it PEG(Passive Entry/Go). LF(Low Frequency) antenna driver which is one of core technologies in PEG is composed of a digital part which processes commands and an analog part which generates sine waveform. The digital part of antenna driver receives commands from MCU(or ECU), and processes requested commands by MCU, and stores antenna-related driver commands and data on an internal FIFO block. The digital part takes corresponding actions for commands read from FIFO and then transfers modulated LF data to analog part. The analog part generates sine waveform and transmits outside through antenna. The designed digital part for LF antenna driver can acomplish faster LF data transmission than that of conventional product. LF antenna driver can be applicable to the areas such as PEG for automotive and gate opening and closing of building.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.71-72
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• 2007

In this study, we investigated the fabrication of MLR (multi-layer resist) with a very thin diamond-like carbon (DLC) layer. ArF PR/$SiO_2$/DLC MLR structure was investigated and etching characteristics of the DLC layer was patterned using $SiO_2$ hard-mask by varying the process parameters such as different high-frequency/low-frequency combination ($f_{LF}/f_{HF}$), HF/LF power ratio ($P_{HF}/P_{LF}$), $O_2$ flow and $N_2$ flow rate in $O_2/N_2$/Ar plasmas. The results indicated an increased etch rate of DLC for the higher $f_{LF}/f_{HF}$ combination and for the increased low-frequency power ($P_{LF}$). And the etch rate of DLC was decreased with increasing the $N_2$ flow rate in $O_2/N_2$/Ar plasmas. In order to confirm the application of DLC MLR for the etching process of silicon oxide, the stack of ArF PR/BARC/$SiO_2$/DLC/TEOS/Si was investigated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.12
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• pp.941-947
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• 2017

This paper reports a fractional-N phase-locked-loop(PLL) frequency synthesizer that is implemented in a $0.35-{\mu}m$ standard CMOS process and generates a quadrature signal for an FRS terminal. The synthesizer consists of a voltage-controlled oscillator(VCO), a charge pump(CP), loop filter(LF), a phase frequency detector(PFD), and a frequency divider. The VCO has been designed with an LC resonant circuit to provide better phase noise and power characteristics, and the CP is designed to be able to adjust the pumping current according to the PFD output. The frequency divider has been designed by a 16-divider pre-scaler and fractional-N divider based on the third delta-sigma modulator($3^{rd}$ DSM). The LF is a third-order RC filter. The measured results show that the proposed device has a dynamic frequency range of 460~510 MHz and -3.86 dBm radio-frequency output power. The phase noise of the output signal is -94.8 dBc/Hz, and the lock-in time is $300{\mu}s$.

• Speech Sciences
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• v.13 no.3
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• pp.49-65
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• 2006

Recently, several theories on the digital speech signal processing expanded the communication boundary between human beings and machines drastically. The aim of this study is to collect dialectal speech in Korea on a large scale and to establish a digital speech data base in order to provide the data base for further research on the Korean dialectal and the creation of value-added network. 528 informants across the country participated in this study. Acoustic characteristics of vowels and consonants are analyzed by Power spectrum and Spectrogram of CSL. Test words were made on the picture cards and letter cards which contained each vowel and each consonant in the initial position of words. Plot formants were depicted on a vowel chart and transitions of diphthongs were compared according to dialectal speech. Spectral times, VOT, VD, and TD were measured on a Spectrogram for stop consonants, and fricative frequency, intensity, and lateral formants (LF1, LF2, LF3) for fricative consonants. Nasal formants (NF1, NF2, NF3) were analyzed for different nasalities of nasal consonants. The acoustic characteristics of dialectal speech showed that young generation speakers did not show distinction between close-mid /e/ and open-mid$/\epsilon/$. The diphthongs /we/ and /wj/ showed simple vowels or diphthongs depending to dialect speech. The sibilant sound /s/ showed the aspiration preceded to fricative noise. Lateral /l/ realized variant /r/ in Kyungsang dialectal speech. The duration of nasal consonants in Chungchong dialectal speech were the longest among the dialects.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.387-392
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• 2018

The aim of this study was to determine the statistical significance of heart rate variability(HRV) between sleep stages, Apnea-hypopnea index(AHI) and age in patients with obstructive sleep apnea(OSA). This study evaluated the main parameters of HRV over time domain and frequency domain in 40 patients with sleep apnea. The non-REM(sleep stage) was statistically validated by comparing the AHI degree of the three groups(mild, moderate, severe) of sleep apnea patients. The NN50(p=0.043), pNN50(p=0.044), VLF peak(p=0.022), LF/HF(p=0.028) were statistically significant in the R-R interval of patients with sleep apnea from the control group (p<0.05). The LF / HF (p = 0.045) and HF power (p = 0.0395) parameters between the non-RAM sleep (sleep 2 phase) and REM sleep in patients with sleep apnea were statistically significant in the control group(p<0.05). We may be able to provide a basis for understanding the correlation among AHI, sleep stage and age and heart rate variability in patients with obstructive sleep apnea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.797-804
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• 2014

The experimental design method based-on the measured data in the several LF monopole antenna was used in MF monopole antenna design. The design technique is also utilized in MF DGPS antenna design. It is not possible to predict the antenna performance of the MF short-monopole antenna because of simple experimental antenna design. Furthermore, it is difficult to design and analyze the various wired short-monopole antenna. The antenna models for performance analysis of the DGPS antenna with the various wired short-monopole structure are proposed in this paper. Based on the proposed antenna models, also, the antenna performance and design data of the wired short-monopole antennas are presented. To evaluate the validity of the analyzed antenna models, the wired short-monopole antenna for 100 kHz are modeled and analyzed. The antenna performance of the wired short-monopole antenna are compared with those of the previously presented LF antenna performance. Based on the evaluation for proposed antenna analyzing models, the DGPS wired short-monopole antennas are modeled and analyzed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1011-1012
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• 2010