• Journal of the Institute of Convergence Signal Processing
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• v.6 no.2
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• pp.95-99
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• 2005

This paper presents an accurate recovery method of the reference clock which is needed for network synchronization in two-way satellite multimedia systems compliant with DVB-RCS specification and which use closed loop method for burst synchronization. In these systems, the remote station transmits TDMA burst via return link. For burst synchronization, it obtains reference clock from program clock reference (PCR) defined by MPEG-2 system specification. The PCR is generated periodically at the hub system by sampling system clock which runs at 27MHz $\pm$ 30ppm. Since the reference clock is recovered by means of digital PLL(DPLL) using imprecise PCR values due to variable random jitter, the recovered clock frequency of remote station doesn't exactly match reference clock of hub station. We propose a robust recovery method of reference clock against random delay jitter The simulation results show that the recovery error is remarkably decreased from 5 clocks to 1 clock of 27MHz relative to the general DPLL recovery method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8B
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• pp.787-795
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• 2002

This paper presents the architecture and the implementation of a 2K/4K/8K-point complex Fast Fourier Transform(FFT) processor for Orthogonal Frequency-Division Multiplexing (OFDM) system. The architecture is based on the Cooley-Tukey algorithm for decomposing the long DFT into short length multi-dimensional DFTs. The transposition memory, shuffle memory, and memory mergence method are used for the efficient manipulation of data for multi-dimensional transforms. Booth algorithm and the COordinate Rotation DIgital Computer(CORDIC) processor are employed for the twiddle factor multiplications in each dimension. Also, for the CORDIC processor, a new twiddle factor generation method is proposed to obviate the ROM required for storing the twiddle factors. The overall 2K/4K/8K-FFT processor requires 600,000 gates, and it is implemented in 1.8 V, 0.18 ${\mu}m$ CMOS. The processor can perform 8K-point FFT in every 273 ${\mu}s$, 2K-point every 68.26 ${\mu}s$ at 30MHz, and the SNR is over 48dB, which are enough performances for the OFDM in DVB-T.

• Journal of Broadcast Engineering
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• v.15 no.5
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• pp.681-696
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• 2010

In this paper, we examined the possibility of the transmission capacity increase by an extension and a modification of ATSC 8-VSB transmission system[1] for broadcasting a 3D HDTV services through 6 MHz terrestrial channel. First we examined the performance and the limit of conventional ATSC 8-VSB transmission system. After that LDPC & BCH code are employed instead of conventional RS & TCM code and the transmission parameter is founded for the capacity increase with resonable TOV by varying the code-rates and increasing the modulation constellation. We do not consider the perfect backward compatibility for maximum transmission capacity increase like DVB-S2 system.

• Journal of the Korean Chemical Society
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• v.50 no.2
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• pp.116-122
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• 2006

In this study we extracted DNA from 100 tissues of breast cancer patients and 103 normals. Then we confirmed single-nucleotide polymorphism(SNP) using PCR-DHPLC(polymerase chain reaction-denaturing high performance liquid chromatogrphy).Also, we studied SNP of samples using several columns to identify relation between packing materials of column and resolution.As a result, we identified 4 C/A, C/G genotypes(4%) in exon 5 and 37 T del genotypes(37%) in exon 8 among 100 breast cancer tissues and 2 in exon 5, 9 in exon 8 among 103 normal samples.In resolution test, we confirmed that PS-DVB(poly styrene-divinylbenzen) column is more efficient than C18 column.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.123-124
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• 2007

In this paper a comparison of several coarse time synchronization(CTS) algorithms for OFDM is presented. The goal of a CTS is to achieve a timing estimate that avoids IST in the receiver. Five coarse timing estimation algorithms are examined and their performances are compared associated with hardware complexity. Simulations has been performed for DVB-T 2K system in thee different channels.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.8
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• pp.4092-4104
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• 2017

In this paper, an efficient 4K and 8K UHD(Ultra High Definition) transmission scheme is proposed on the convergence networks with broadcasting and LTE(Long Term Evolution) by using CoMP(Coordinated Multi-Point). A video data is compressed and divided into BL(Base Layer), E(Enhanced layer)1, E2 and E3 by scalable HEVC(High Efficiency Video Coding). The divided layers can be combined by the scalable HEVC such as mobile HD, full HD, 4K and 8K UHD(Ultra High Definition). The divided layers are transmitted through the convergence networks with DVB-T2(Digital Video Broadcasting-$2^{nd}$ Generation Terrestrial) broadcasting system and LTE CoMP. This scheme transmits mobile HD and full HD layers through DVB-T2 broadcasting system by using M-PLP(Multiple-physical Layer Pipes), and adaptively transmits 4K or 8K UHD layer through LTE CoMP with MMT(MPEG Media Transport) server. An adaptive transmitting and receiving scheme in the LTE CoMP system provides 4K or 8K UHD layer to a user according to the user status. The proposed scheme is verified by showing the system-level simulation results which is better BER(bit-error-rate) performance than the conventional scheme. The results show that the proposed scheme provides the stable video contents to the user especially at the cell edge.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.7
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• pp.380-388
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• 2014

Transmission methods for terrestrial UHDTV broadcasting have been actively studied in order to provide enhanced broadcasting service in many countries. Most of the countries are considering multi-carrier transmission methods based on OFDM and some of them have performed UHDTV experimental broadcasting by using the DVB-T2 standard with the adoption of an improved data compression technique. However, since single carrier transmission methods, which are known to be susceptible to multi-path fading, could remedy this defect by using the SC-FDE method where a frequency domain equalizer is utilized in the receiver, they may achieve a similar transmission performance with multi-carrier transmission methods. In consideration of these circumstances, we compare the transmission performances of two-type methods to provide a decision criterion on a suitable transmission method for UHDTV broadcasting.

• Journal of Adhesion and Interface
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• v.13 no.3
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• pp.109-115
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• 2012

Monodisperse blue-colored poly(styrene-co-acrylic acid) latices were successfully prepared by seeded emulsion polymerization. Blue-colored latices with carboxyl anionic charge on the surface were synthesized at the second stage with the introduction of Blue 606 dye, acrylic acid, and 0.21 ${\mu}m$-polystyrene seed. All the blue-colored latices synthesized in this study were in the size range of 0.25~0.42 ${\mu}m$ and all uniform with less than 1.01 in PSD. The particle size increased with the addition of acrylic acid being delayed and colloidally stable latices were obtained over 30 min after its addition. The blue-colored latex with 20 wt% acrylic acid showed -145 mV of zeta-potential and $-9.4{\times}10^{-6}\;cm^2/Vs$ of electrophoretic mobility, and with 25 wt% of DVB showed high $T_g$ at 396.7 K.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.2
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• pp.55-67
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• 2005

Separation between computation and communication in system design allows the system designer to explore the communication architecture independently of component selection and mapping. In this paper we present an iterative two-step exploration methodology for bus-based on-chip communication architecture and memory allocation, assuming that memory traces from the processing elements are given from the mapping stage. The proposed method uses a static performance estimation technique to reduce the large design space drastically and quickly, and applies a trace-driven simulation technique to the reduced set of design candidates for accurate Performance estimation. Since local memory traffics as well as shared memory traffics are involved in bus contention, memory allocation is considered as an important axis of the design space in our technique. The viability and efficiency of the proposed methodology arc validated by two real -life examples, 4-channel digital video recorder (DVR) and an equalizer for OFDM DVB-T receiver.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.9
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• pp.1654-1665
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• 2008

This paper presents bit splitting methods to apply multilevel modulation to iterative codes such as turbo code, low density parity check code and turbo product code. Log-likelihood ratio method splits multilevel symbols to soft decision symbols using the received in-phase and quadrature component based on Gaussian approximation. However it is too complicate to calculate and to implement hardware due to exponential and logarithm calculation. Therefore this paper presents Euclidean, MAX, sector and center focusing method to reduce the high complexity of LLR method. Also, this paper proposes optimal soft symbol split method for three kind of iterative codes. Futhermore, 16-APSK modulator method with double ring structure for applying DVB-S2 system and 16-QAM modulator method with lattice structure for T-DMB system are also analyzed.