• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.534-537
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• 1999

This paper describes a design of pipelined adaptive decision-feedback equalizer (PADFE) for high bit-rate wireless digital communication systems. To enhance the throughput rate of ADFE, two pipeline stages are inserted into the critical path of ADFE by using delayed least-mean-square (DLMS) algorithm. Redundant binary (RB) arithmetic is applied to all the data processing of ADFE including filter laps and coefficient update blocks. When compared with conventional methods based on two's complement arithmetic, the proposed approach reduces arithmetic complexity, as well as results in a very simple complex-valued filter structure, thus suitable for VLSI implementation. The design parameters (filter tap, coefficient and internal bit-width, etc.) and equalization performance (bit error rate, convergence speed, etc.) are analyzed by algorithm-level simulation using COSSAP. The PADFE was designed using VHDL and Synopsys, and mapped into two ALTERA FLEX10k100 FPGAs.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.6
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• pp.446-452
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• 2004

Under the condition of a common narrowband target signal and interference signals from several directions, the linearly constrained minimum variance (LCMV) method using the generalized sidelobe canceller (GSC) for adaptive beamforming has been exploited successfully However, in the case of wideband signals, the length of the adaptive filter must be extended. As a result, the complexity of the beamformer increases, which makes real-time implementation difficult. In this paper, we improve the convergence characteristics of the adaptive filter using the transform domain normalized least mean square (NLMS) approach based on the subband GSC structure without the increase of complexity. Besides, the M-MAX algorithm, which is one of various selective coefficient updating methods, is employed in order to remarkably reduce the computational cost without decreasing the convergence quality. With the combination of these methods, we propose a computationally efficient wideband adaptive beamformer and verify its efficiency through a series of simulations.

• KIEE International Transactions on Power Engineering
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• v.3A no.2
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• pp.85-92
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• 2003

When a current transformer (CT) is saturated, the wave-shape of the secondary current is distorted and contains points of inflection, which correspond to the start or end of each saturation period. Discontinuity in the first-difference function of the current arises at points of inflection, where the second and third differences convert into pulses that can be used to detect saturation. This paper describes the design and evaluation of a CT saturation detection technique using the third-difference function and includes the countermeasure for a spike signal. Test results clearly demonstrate that the algorithm successfully detects the start and end of each saturation period irrespective of the remanent flux and magnetization inductance in the saturated region. This paper concludes by describing the results of hardware implementation of the algorithm using a DSP.

• Annual Conference of KIPS
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• 2004.11a
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• pp.187-190
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• 2004

This paper proposes an efficient hardware implementation of SPIHT(Set Partitoning In Hierarchical Tree) algorithm for image compression with the discrete wavelet transform. An efficient technique to scan the coefficients which are located in partitioned spatial orientation trees by DWT is considered in terms of counter fields for sorting pass and refinement pass. The proposed image compression method using SPIHT has been modeled in VHDL and has been implemented by use of both TMS320C6000 as a DSP and Virtex2 as a Xilinx FPGA.

• The KIPS Transactions:PartC
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• v.8C no.3
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• pp.277-286
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• 2001

본 논문에서는 미국 국립표준기술연구소 차세대 표준 암호 알고리듬으로 선정한 Rijndael 암호 알고리듬과 안정성과 성능에서 인정을 받은 Twofish 암호 알고리듬을 ALTERA FPGA를 사용하여 하드웨어로 구현한다. 두가지 알고리듬에 대해 키스케쥴링과 인터페이스를 하드웨어에 포함시켜 구현한다. 알고리듬의 효율적인 동작을 위해 키스케쥴링을 포함하면서도 구현된 회로의 크기가 크게 증가하지 않으며, 데이터의 암호/복호화 처리 속도가 향상됨을 알 수 있다. 주어진 128-비트 대칭키에 대하여, 구현된 Rijndael 암호 알고리듬은 11개의 클럭 만에 키스케쥴링을 완료하며, 구현된 Twofish 암호 알고리듬은 21개의 클럭 만에 키스케쥴링을 완료한다. 128-비트 입력 데이터가 주어졌을 때, Rijndael의 경우, 10개의 클럭 만에 주어진 데이터의 암호/복호화를 수행하고, Twofish는 16개의 클럭 만에 암호/복호화를 수행한다. 또한, Rijndael은 336.8Mbps의 데이터 처리속도를 보이고, Twofish는 121.2Mbps의 성능을 보임을 알 수 있다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.3
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• pp.750-757
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• 1999

The protocol conformance testing is to check whether an implementation of a protocol conforms to its specification. And it is important to improve the interoperability of protocol and the efficiency of cost. In general, protocol is composed of the control flow representing observable behaviors and the data flow representing internally used variables. Until now, research for generation of test suite has been realized only consideration the control flow of protocol or separation control flow from data flow. Case of considering control flow, contents of test was simple and definite. Length of test was short. But it was of little application, and it didn't manage each kind errors in data flow. Therefore, we must generate test case that can manage control and data flow. So, anomaly of variable must be removed for efficient conformance testing. Therefore in this dissertation, we proposed algorithm which can remove anomaly of variable for efficient conformance testing. And it showed that anomaly of variable was got rid of applying this algorithm to real protocol.

• Annual Conference of KIPS
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• 2003.11c
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• pp.1737-1740
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• 2003

There are many security problems in the electronic payment system because it is built into the open network. Security problems include both system penetrations from outside and unauthorized access by the inside. Nevertheless, the integrity of messages can be guaranteed through a transfer message with the SEED and HASH encryption algorithm. This paper demonstrates how electronic payment system messages and the information they contain can be made safeguarded using the SEED and HASH encryption algorithm, even when there may be some information loss.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3246-3248
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• 1999

The APC is a coding algorithm which has the middle property of both Wave Coding(ex ADPCM) and Vocoding(ex CELP) and can decode a proper quality of sound by using scalar quantizer instead of vector quantizer at computation a low calculation. So, the APC required for Voice Codec of INMARSAT-B could be successfully implemented by full duplex using TMS32OC30(DSP).

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.395-397
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• 1996

The existing CPC(Center Position Controller) has unstably performed because of dusts on reflection panel, CCD protector contamination due to high temperature in furnace or other parameters. The reason is that the existing CPC has a Z80 processor as a CPU and only performs low level image processing as a simple edge detector. So the improvement of control system through the development of robust edge detection algorithm overcoming changes of measuring environment is needed. For this, in this study we carefully analyze the image of the strip rolled in occasion that measuring environment is changing, develop the optimal edge detection algorithm to solve the problems, generate the control signal suitable for the existing CPC(Center Position Controller), and propose the capability of application to the actual environment.

• Annual Conference of KIPS
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• 2014.11a
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• pp.227-230
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• 2014

LTE 3GPP standard defines several QCI (QoS Class Identifier) classes to provide differential QoS, depending on the requirements of different user applications.These QCI values have been characterized in terms of priority, packet loss and delay budget. In spite of the availability of this robust QoS framework in LTE, there is no such scheduling algorithm that has its working principle based on this framework. The responsibility of fulfilling the user requirements, while satisfying the service class requirements is left upon the cellular service provider and it is an open issue at present. To solve this problem, we have proposed a MAC scheduler, which defines the priority of different users based on their bearer specification and provides desired QoS in terms of the achieved throughput through the resource block allocation based on calculated user priority.