• Journal of Communications and Networks
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• v.8 no.3
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• pp.257-266
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• 2006

The powerful benefits of multi-antenna systems can be obtained by cooperative communications among users in multiple access environments without the need for physical arrays. This paper studies a novel cooperative signaling strategy that achieves high performance and low implementation complexity for synchronous code division multiple access (CDMA) wireless mobile networks. The validity of the proposed strategy under slow flat Rayleigh fading channel plus additive white Gaussian noise (AWGN) is verified through closed-form error probability expressions and MonteCarlo simulations. A variety of analytical results reveal that the new cooperative strategy significantly outperforms direct transmission subject to the same spectral efficiency and transmit power constraint.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2678-2680
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• 2003

본 논문에서는 sliding-DFT의 순환구현을 기반한 실시간 위상 측정 앨고리즘을 제시하였다. 종래의 순환형 SDFT 기반 위상 측정 기법은 단일 계수를 사용하기 때문에 계수 근사가 적용되는 하드웨어 구현시 심각한 오차 파급 특성을 나타낸다. 본 논문에서는 순환 구조이면서 회전 위상을 보정을 통해 N-point DFT의 N개의 모든 계수를 적용한 위상 측정 기법을 제시하였고, FPGA 등 하드웨어 구현에 있어서 계수의 유한 비트 근사에 따르는 성능 열화를 해석하였다. 제안한 위상측정 앨고리즘은 실시간 다채널 위상 측정이 가능하도록 FPGA에 구현하였고 동작을 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06b
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• pp.79-86
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• 1999

본 논문에서는 ISO/IEC MPEG-2 AAC 표준을 기반으로 한 멀티채널 오디오 인코더 및 디코더(MASIC) 시스템의 실시간 구현 기술에 대해서 기술한다. MPEG-2 AAC 기술은 멀티채널 오디오 부호화 방식의 국제 표준으로써, 지금까지 개발된 멀티채널 오디오 부호화 방식중 최신의 기술이며, 압축율과 오디오 품질이 가장 우수한 것으로 알려져 있다. MASIC 시스템은 인코딩 및 디코딩 기술의 실시간 처리를 위하여 범용 DSP인 TMS320C6701을 사용하였고, 멀티채널 오디오의 고속 입력과 출력을 위한 디지털 인터페이스를 가지고 있으며, 개인용 컴퓨터와의 인터페이스를 위한 PCI 기술이 적용되어 다양한 입출력 모드를 지원하는 특징을 갖는다.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.11
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• pp.156-159
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• 1993

In this paper, computerized BEAM (brain electrical activity map) was implemented for objective and quantitative multichannel EEG analysis. BEAM is calculated by 4 point Interpolation method and number of elements are 5140. Representation methods of BEAH are two. One is dot density method which classify brain electrical potential 9 levels by dot density and the other is color method which classify brain electrical 12 levers by different colors. In this BEAM, instantaneous change and average energy distribution over any arbitrary time interval of brain electrical activity could be observed and analyzed easily.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.234-235
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• 2002

최근 전력 및 산업기기의 전기량. 물리량 등을 측정하기 위한 광계측 시스템에 사용되는 광커넥터는 산업 현장의 환경적인 제약 조건을 만족할 수 있는 새로운 구조의 다심 광커넥터가 요구되고 있다. 본 논문에서는 이러한 것을 배경으로 하여 전력설비의 절연 내력 등을 향상시킬 목적으로 기기 내부에 충전한 가스 및 절연유 등의 누설을 방지하고. 낮은 손실로 광계측 신호들을 동시에 전달 및 단락시킬 수 있는 광전압 전류 계측용 멀티채널 광커넥터를 제안하고, 시제품의 제작 및 특성시험의 결과에 대해서 기술하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.3
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• pp.326-331
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• 2010

This paper presents the design and implementation of a data acquisition system with a large number of multi-channels for manufacturing machine. The system having a throughput of 800-ch analog signals has been designed with Quartus II tool and Cyclone II FPGA. The proposed system is suitable for the large scale data handling in order to distinguish whether the operation is correct or not. The designed system is composed of a control unit, voltage divider and USB interface. To reduce the data throughput, we utilized an algorithm which can extract the same data from the achieved data. The test results of the system adapted to a manufacturing machine, show a relevant data acquisition operation of 800 channels in short time.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.5
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• pp.997-1006
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• 2019

To overcome the difficulties and inefficiencies of the existing power analysis attack, we try to extract the secret key embedded in a cryptographic device using attack model based on MLP(Multi-Layer Perceptron) method. The target of our proposed power analysis attack is the AES-128 encryption module implemented on an 8-bit processor XMEGA128. We use the divide-and-conquer method in bytes to recover the whole 16 bytes secret key. As a result, the MLP-based power analysis attack can extract the secret key with the accuracy of 89.51%. Additionally, this MLP model has the 94.51% accuracy when the pre-processing method on power traces is applied. Compared to the machine leaning-based model SVM(Support Vector Machine), we show that the MLP can be a outstanding method in power analysis attacks due to excellent ability for feature extraction.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4357-4366
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• 2023

MARS-KS, a domestic regulatory confirmatory code of Republic of Korea, had been developed by integrating RELAP5/MOD2 and COBRA-TF. The integration of COBRA-TF allowed to extend the capability of MARS-KS, limited to one-dimensional analysis, to multi-dimensional analysis. The use of COBRA-TF was mainly focused on subchannel analyses for simulating multi-dimensional behavior within the reactor core. However, this feature has been remained as a legacy without ongoing maintenance. Meanwhile, MARS-KS also includes its own multidimensional component, namely MULTID, which is also feasible to simulate three-dimensional convection and diffusion. The MULTID is capable of modeling the turbulent diffusion using simple mixing length model. The implementation of the turbulent mixing is of importance for analyzing the reactor core where a disturbing cross-sectional structure of rod bundle makes the flow perturbation and corresponding mixing stronger. In addition, the presence of this turbulent behavior allows the secondary transports with net mass exchange between subchannels. However, a series of assessments performed in previous studies revealed that the turbulence model of the MULTID could not simulate the aforementioned effective mixing occurred in the subchannel-scale problems. This is obvious consequence since the physical models of the MULTID neglect the effect of mass transport and thereby, it cannot model the void drift effect and resulting phasic distribution within a bundle. Thus, in this study, the turbulence mixing model of the MULTID has been improved by means of the inter-channel mixing model, widely utilized in subchannel analysis, in order to extend the application of the MULTID to small-scale problems. A series of assessments has been performed against rod bundle experiments, namely GE 3X3 and PSBT, to evaluate the performance of the introduced mixing model. The assessment results revealed that the application of the inter-channel mixing model allowed to enhance the prediction of the MULTID in subchannel scale problems. In addition, it was indicated that the code could not predict appropriate phasic distribution in the rod bundle without the model. Considering that the proper prediction of the phasic distribution is important when considering pin-based and/or assembly-based expressions of the reactor core, the results of this study clearly indicate that the inter-channel mixing model is required for analyzing the rod bundle, appropriately.

• The Journal of the Acoustical Society of Korea
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• v.20 no.6
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• pp.34-39
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• 2001

An adaptive multi-rate (AMR) speech coder was adopted as a standard of W-CDMA by 3GPP and ETSI. The AMR coder is based on the CELP algorithm operating at rates ranging from 12.2 kbps down to 4.75 kbps, and it is a source controlled codec according to the channel error conditions and the traffic loading. In this paper, we implement the DSP S/W of the AMR coder using OakDSPCore. The implementation is based on the CSD17C00A chip developed by C&S Technology, and it is tested using test vectors, for the AMR speech codec, provided by ETSI for the bit exact implementation. The DSP B/W requires 20.6 MIPS for the encoder and 2.7 MIPS for the decoder. Memories required by the Am coder were 21.97 kwords, 6.64 kwords and 15.1 kwords for code, data sections and data ROM, respectively. Also, actual sound input/output test using microphone and speaker demonstrates its proper real-time operation without distortions or delays.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.8
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• pp.481-487
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• 2014

In this paper, we have proposed gigabit serial transceiver based on backplane architecture at the satellite communication digital transponder. The transponder supports the full combinational switching function with broadband multi-channel using programmable device - Xilinx space-grade Virtex-5 FPGA. In order to implement the switching function, GTX transceiver solution inside Virtex-5 FPGA is used. Also hardware implementation is simple because of no additional component. In order to use a GTX transceiver, signal integrity(SI) simulation of PCB design is essential. We investigate the characteristics of the S-parameter, eye diagram, channel jitter of GTX transmission line and conform that GTX Transceiver operates without error. Finally the proposed PCB design will be utilized at satellite communication digital transponder EQM-2(Engineering Qualification Model-2).