• Proceedings of the IEEK Conference
• /
• 2000.06a
• /
• pp.69-72
• /
• 2000

This paper shows the more improved design of MRI receiver compared to conventional one based on Elscint Spectrometer. At first, the low-cost ADC is 16 bits, 3MHz sampling A/D converter Comparing to conventional one with signal bits of 14 bits, this device with those of 16 bits helps getting Improved the image resolution improved. If frequency is designed centering around 7.6 MHz to be satisfied in 10 MHz of maximum input bandwidth of ADC. For 1st demodulation, fixed IF is used for the purpose of the implementing multi nuclei system. Control parts & partial digital parts are integrated on one chip(FPGA). In DDC(Digital Down Converter), we got required bandwidth of LPF by controlling its decimation rate. With above considerations, we designed optimal receiver for high resolution imaging to be implemented through PC interface & experimental test of receiver of MRI after receiver's fabrication.

• Proceedings of the Acoustical Society of Korea Conference
• /
• spring
• /
• pp.107-110
• /
• 2000

음성 신호는 시간에 따라 변하지만 일정 구간에서는 특성이 변하지 않는다고 가정하여 윈도우를 취해 단구간 분석을 한다. 이 때 윈도우의 적용은 필수적이다. 하지만 단구간 분석을 위해서 사용되는 윈도우에 의해 생기는 누설에너지 때문에 음성신호의 스펙트럼 정보가 왜곡되어 버린다. 본 논문에서는 스펙트럼 분석 시 발생되는 누설에너지를 최소화하는 방법을 제안하고자 한다. 음성신호에 고정된 크기의 rectangular Window를 취한 후 처음 샘플과 차이가 가장 작은 샘플을 프레임 크기의 3/4인 지점에서부터 검색하여 최소인 부분까지 시간 축 스케일링을 한 후 기존의 윈도우 크기와 같은 크기로 만든다. interpolation과 decimation을 조합하여 시간 축 스케일링을 한다. 이렇게 윈도우가 적용된 신호를 처리 후 위의 역 과정을 수행한다. 제안한 윈도우의 SNRseg는 rectangular window보다 평균 7.88dB 낮고, kaiser window보다 평균 1.65dB 높았다. 또한 제안한 윈도우의 SD는 rectangular window 보다 평균 $1.73dB^\2$ 낮았다.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.887-890
• /
• 1998

We present a novel multi-resolution block matching algorithm (BMA) for fast motion estimation. At the coarsest level, a full search BMA (FSBMA) is performed for searching complex or random motion. Concurrently, spatial correlation of motion vector (MV) field is used for searching continuous motion. Here we present an efficient method for searching full resolution MVs without MV decimation even at the coarsest leve. After the coarsest level search, two or three initial MV candidates are chosen for the next level. At the further levels, the MV candidates are refined within much smaller search areas. Simulation results show that in comparison with FSBMA, the proposed BMA achieves a speed-up factor over 710 with minor PSNR degradation of 0.2dB at most, under a normal MPEG2 coding environment. Furthermore, our scheme is also suitable for hardware implementation due to regular data-flow.

• Proceedings of the IEEK Conference
• /
• 2000.09a
• /
• pp.755-758
• /
• 2000

본 논문에서는 AMR(Adaptive Multi-Rate)를 이용하여 광대역 음성부호화기를 설계하였다. 16kHz로 샘플링 된 입력 신호를 QMF 필터에 의해 두 개의 대역으로 나누어, 각각 decimation하여 두 개의 8kHz 샘플링 신호로 변환시킨 후 저대역(0Hz-3400Hz)의 신호와 고대역(3400Hz -7000Hz)의 신호로 나누어 각각 부호화한다. 나누어진 두 개의 협대역 음성신호는 AMR(Adaptive Multi-Rate)과 ATC(Adaptive Transform Coding)을 사용하여 각각 부호화되어 전송된다. 두 대역으로부터 부호화된 정보는 20.2kbps에서 12.75kbps까지의 전송률을 갖고, 수신단에서는 각 대역을 AMR과ATC방법으로 역부호화하여 음성신호를 합성한다. 설계된 광대역 음성부호화기의 성능을 평가하기 위해 ITU-T의 표준안인 G.722를 포함하여 MOS 시험을 하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 1999.11b
• /
• pp.47-52
• /
• 1999

The visualization of Moire or laser-scanned data has been explored by many researchers and has been an important issue on computer graphics research. In this paper, we present various techniques that handle tremendous amount of 3D range data which are generated by the ETRI- Moire Scanner. The techniques include constructing an efficient data structure, constructing triangle meshes and decimation and registration of multiple-view range images and textures.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.7 no.4
• /
• pp.827-832
• /
• 2012

In this paper, we present a new decimated Gold-like m-sequence with a binary m-sequence of period $2^n-1$. And we show that the cross-correlation function of the proposed sequence is four-valued.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.7 no.4
• /
• pp.821-826
• /
• 2012

p-ary sequences of period $N=2^k-1$ are widely used in many areas of engineering and sciences. Some well-known applications include coding theory, code-division multiple-access (CDMA) communications, and stream cipher systems. The analysis of cross-correlations of these sequences is a very important problem in p-ary sequences research. In this paper, we analyze cross-correlations of p-ary sequences which is associated with the equation $(x+1)^d=x^d+1$ over finite fields.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.8
• /
• pp.1128-1135
• /
• 1993

In this paper, new binary cyclic codes (hereafter, refered to as GMW code) which are generated by using GMW sequence, g(t) = tr((trk(a))r), and its cyclic shifts are introduced. Code length of GMW codes is 2a-1, where k is composite integer, e·J. Dimension of the GMW codes is k(k/j)w-1, where w is a Hamming weight of r. Several properties of GMW codes such as designed distance, minimum distance, and weights of code words are obtained in terms of parameters of GMW sequences. And expansion of GMW sequences in terms of m-sequence and its decimation sequences are introduced and characteristic polynomials of GMW sequences are also derived.

• Proceedings of the KIEE Conference
• /
• 1989.07a
• /
• pp.138-141
• /
• 1989

In resent years, aided by the power and capability of digital computation, the techniques of Walsh Transform have been exploited for applications in commun- ication and signal processing. This paper presents an approach of FWT by using a 16- bit word-length micro- computer. This FWT implements an in-placed decimation-in-sequency algorithm which improves processing speed and memory storage. Several examples illustrate the process and demonstrate the power spectrum of FWT and that of FFT for the waveforms

• Journal of Institute of Control, Robotics and Systems
• /
• v.5 no.2
• /
• pp.220-227
• /
• 1999

The position control accuracy of a robot arm is significantly deteriorated when a long slender arm robot is operated at a high speed. In this case, the robot arm needs to be modeled as a flexible structure, not a rigid one, and its control system needs to be designed with its elastic modes taken into account. In this paper, the vibration control scheme of a one-link flexible manipulator using adaptive input shaper in conjunction with PID controller is presented. The robot consists of a flexible arm manufactured with a thin aluminium plate, an AC servo motor with a harmonic drive for speed reduction, an optical encoder and an accelerometer. On-line identification of the vibration mode is done using the pruned decimation-in-time FFT algorithm to estimate the parameter of the input shaper. Experimental results of the flexible manipulator with a PID controller and input shaper are provided to show the effectiveness of the advocated controllers.