• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.63-69
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• 2008

Reconfigurable RF one-chip solutions have been researched with the objective of designing for smaller-sized and more economical RF transceiver and it can be applied to a vehicular wireless terminal. The proposed voltage-controlled oscillator satisfies the targeted frequency range ($4.2{\sim}5.4\;GHz$) and the frequency planning which correspond to the standards such as CDMA(IS-95), PCS, GSM850, EGSM, WCDMA, WLAN, Bluetooth, WiBro, S-DMB, DSRC, GPS, and DVB-H/DMB-H/L(L Band). In order to improve phase noise performance, PMOS is adopted in the cross-coupled pair, the tail current source and MOS varactor in this VCO and differential-typed switching is proposed in capacitor array. Based on the measurement results, a total power dissipation is $5.3{\sim}6.0\;mW$ at 1.8 V power supply voltage. The oscillator is tuned from 4.05 to 5.62 GHz; The tuning range is 33%. The phase noise is -117.16 dBc/Hz at 1 MHz offset frequency and the FOM (Figure Of Merit) is $-180.84{\sim}-180.5$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.12
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• pp.75-82
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• 2010

This paper presents a wideband ${\Delta}{\Sigma}$ fractional-N frequency synthesizer for a multi-band single chip CMOS RFIC transceivers. A wideband VCO utilizes a 6-bit switched capacitor array bank for 2340~3940 MHz frequency range. VCO frequency calibration circuit is designed for optimal capacitor bank code selection before phase locking process. It finishes the calibration process in $2{\mu}s$ over the whole frequency band. The LO generation block has selectable multiple division ratios of ${\div}2$, ${\div}16$, and ${\div}32$ to generate LO I/Q signals for T-DMB/DAB/FM Radio systems in L-Band (1173~1973 MHz), VHF-III (147~246 MHz), VFH-II (74~123 MHz), respectively. The measured integrated phase noise is quite low as it is lower than 0.8 degree RMS over the whole frequency band. Total locking time of the ${\Delta}{\Sigma}$ frequency synthesizer including VCO frequency calibration time is less than $50{\mu}s$. The wideband ${\Delta}{\Sigma}$ fractional-N frequency synthesizer is fabricated in $0.13{\mu}m$ CMOS technology, and it consumes 15.8 mA from 1.2 V DC supply.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.281-284
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• 2004

수년 내 서비스가 개시될 휴대인터넷 서비스는 현재 모든 통신사업자에게 큰 이슈로 떠오르고 있다. 관련산업 포함 연 16조원에 달하는 서비스로서 고속의 이동 무선인터넷 서비스를 제공한다. 그러나 아직 휴대인터넷의 시장에서의 위상이나 기존 서비스와의 대체 보완 관계가 정확히 연구되고 있지 않다. 본 논문에서는 휴대인터넷 서비스의 포지셔닝과 함께 휴대인터넷과 기존의 이동통신, 초고속인터넷, 및 DMB서비스와의 관계를 동시에 살펴본다.

• Journal of Korea Multimedia Society
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• v.14 no.5
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• pp.614-621
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• 2011

This paper presents design of a wide tuning range digitally controlled oscillator(DCO) for Mobile-DTV applications. DCO is the key element of the ADPLL block that generates oscillation frequencies. We proposed a binary delay chain(BDC) structure, for wide tuning range DCO, modifying conventional fixed delay chain. The proposed structure generates oscillation frequencies by delay cell combination which has a variable delay time of $2^i$ in the range of $0{\leq}i{\leq}n-1$. The BOC structure can reduce the number of delay cells because it make possible to select delay cell and resolution. We simulated the proposed DCO by Cadence's Spectre RF tool in 1.8V chartered $0.18{\mu}m$ CMOS process. The simulation results showed 77MHz~2.07GHz frequency range and 3ps resolution. The phase noise yields -101dBc/Hz@1MHz at Mobile-DTV maximum frequency 1675MHz and the power consumption is 5.87mW. The proposed DCO satisfies Mobile-DTV standards such as ATSC-M/H, DVB-H, ISDB-T, T-DMB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1343-1351
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• 2010

In this paper, a novel patch antenna based on the metamaterial CRLH(Composite Right- and Left-Handed) structure is designed, implemented, and measured. Contrary to the standard microstrip patch's fundamental resonance mode of half-wavelength or its positive multiple, the proposed antenna shows the in-phase electric field over the entire antenna. The proposed antenna has a desired omni-directional field pattern which is typical characteristic of $\lambda/4$ monopole antenna, and also shows the merit of low profile. HFSS(High Frequency Structure Simulator) of Ansoft which is based on the FEM(Finite Element Method) is used to simulate the proposed antenna. FR-4 substrate of thickness 1.6 mm and relative permitivity 4.4 is used for the proposed antenna implementation. The implemented antenna showed VSWR (Voltage Standarding Wave Ratio)$\leq$2 for the frequency band from 2.63 GHz to 2.655 GHz which is used for S-DMB (Satellite-Digital Multimedia Broadcasting) service. And measured peak gain and efficiency are 2.65 dBi and 81.14 %, respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.35-40
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• 2011

We have studied the impact and bending characteristics of a dual band antenna (1.575, 2.645 GHz) with composite sandwich construction. Mechanical performance of the antenna can be improved by reinforcing the antenna by sandwiching the planar antenna with layers of carbon fiber-reinforced plastic(CFRP) and glass fiber-reinforced plastic(GFRP) using an adhesive film. According to the ASTM D7137, ASTM C393 and MIL-STD401B, impact and bending test were performed and the S-parameters and gains of the antenna were measured in order to verify electrical and mechanical performance. The maximum contact load and the bending load of the antenna are 4 kN and 400 N and gains of the antenna are 6 dBi and 4.6 dBi in the GPS and DMB bands, respectively. The proposed antenna structure can be applied to surfaces of vehicles.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5A
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• pp.482-489
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• 2010

In this paper we have proposed a new architecture of DQ-IRM(Double-Quadrature Image Rejection Mixer) for image rejection in the low-IF receiver. It consist of a frequency-tunable RF PPF(Poly Phase Filter) and the quadrature mixers. The conventional DQ-IRM generates the quadrature RF signals for the RF wide band at once. But the proposed DQ-IRM with the frequency-tuable RF PPF generates the quadrature RF signals for the narrow band of 2~3 channels bandwidth, which is partitioned from the RF wide band. We designed the CMOS RF tuner for T-DMB(Terrestrial Digital Multimedia Broadcasting) with the proposed 3rd DQ-IRM using a 0.18um CMOS technology and verified the performances of the designed receiver such as the image rejection ratio, the noise figure and the power consumption. The overall NF of the RF tuner is about 1.26 dB and the image reject ratio is about 51 dB. The power consumption is 55.8 mW at 1.8 V supply voltage. The chip area is $3.0{\times}2.5mm^2$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.12 s.91
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• pp.1152-1160
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• 2004

OFDM technique was adopted as the standard of IEEE 802.1 la and it has been widely used for wireless LAN, European DVB/DAB system, Korean DMB system. In the standard of IEEE 802.11a the data packet is composed of two parts, preamble and data. Preamble is composed of short pilots and long pilots, which are used for synchronization and estimation of frequency offset and channel. We can also compensate phase noise effect in the transceiver by using above pilots. The phase noise is more complicate than frequency offset and seriously affects system performance. In this paper, we newly propose CPE and ICI simultaneous compensation method to compensate phase noise generated by transceiver oscillator and compare with previous studies. As results, phase noise effect can be significantly compensated by CPE cancellation method, PNS algorithm and our proposed CPE and ICI compensation method. Especially, the proposed CPE and ICI compensation method can achieve the best BER performance compared with original OFDM, CPE cancellation method and PNS algorithm.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.143-147
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• 2011

3월11일 오후 2시46분경 일본 동북지역을 중심으로 M. 9.0 규모의 동일본대지진이 발생해 수많은 희생자가 나왔다. 지진발생 후 쓰나미가 일어나 방사선이 대량으로 유출되는 등 일본사상 최대의 국가적인 복합재난이 일어났다. 그럼에도 불구하고, 일본인들이 침착함을 잃지 않은 시민의식에 대해 세계 시민들은 극찬을 아끼지 않았다. 우리나라도 국가적으로는 대형 재난발생 시를 대비하여 행정안전부, 방송통신위원회, 소방방재청, 기상청, KBS, 재난전문가 등으로 구성된 가칭 "긴급재난방송협의회" 같은 것을 구성하여 긴밀하게 재난정보를 교환하는 유기적인 협력체제구성이 필요하다. 또, 나아가서는 이들 관련 부서에서는 재난방송 전담관을 두어 재난방송에 적극적으로 대처하여야 할 것으로 본다. 정부도 KBS에 대해 대폭적인 지원을 아끼지 않아야 하겠지만, KBS 또한 지금까지의 대응 자세에서 벗어나 "재난방송의 선진화"를 위해 재난방송시스템을 새로 구축해야 할 것이다. 마지막으로 KBS는 NHK의 지상파방송과 같이 KBS 위상에 걸 맞는 재난방송시스템을 구축하는 한편, 디지털시대에 있어서의 뉴 미디어를 이용하여 DMB나 스마트 폰, SNS 등을 이용한 각종 재난경보체제를 선도해야 할 재난주관방송사로서의 의무가 있다. 그것이 곧 공영방송의 본연의 임무이자 국민의 생명과 재산을 지키는데 최선을 다하는 길이다.

• Archives of design research
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• v.17 no.2
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• pp.451-462
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• 2004

The range of graphic design has expanded very widely as the digital era emerged, and many new areas of film design, including film, DVD, interactive TV, mobile and DMB, began to require the work of designers. This could be considered as an application as well as a case of digital film design as it has more developed new media environment as basis. The change in the expression techniques of film language is inevitable since major consumers of new media are the younger generation. The method of creating and distributing visual communication work is not standing still anymore. It has been diversified through dynamic movements and changes resulting from interaction. The major objective of this study is to find out and suggest the directions that film and digital media graduate school education of future by researching and analyzing how the nature of design, as an academic subject that keeps on changing and developing, is evolving in the new media environment. For this purpose, the methods of appropriate education system in higher design education, which are derived from case studies and previous studies on education system, are evaluated by examining the consumers. This study aims at finding the most effective training method in film and digital media design, and by integrating current design education with digital film design education establish a better fit education system that complies with the demands of today's society. It will suggest how an educational institute should see ahead of the time and provide what the society will demand in the future.