• 한국통신학회논문지
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• 제25권11B호
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• pp.1864-1871
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• 2000

본 논문에서는 차세대 무선 통신 시스템에 적용이 가능한 새로운 FEC(Forward Error Correction) 부호화 방법으로 MLC(Multi-Level Convolutional) 부호화 방식을 제안한다. 차세대 무선통신서비스는 음성, 데이터, 영상 등 많은 종류의 서비스를 함으로써 데이터의 처리속도가 빠른 시스템이 요구된다. 데이터 처리시간을 단축시키기 위한 방법으로 다중 레벨을 이용하여 부호어를 만들어 내는 방식의 부호화 시스템을 설계하였다. MLC는 부호 처리시간을 단축시킬 뿐만 아니라 다양한 알고리즘을 이용해 부호어를 만들어 낼 수 있다는 특징을 가지게 된다. 모의실험은 MLC 코드의 두 가지 방법, Modulo- operation 방식과 Galois Field-Operation 방식을 이용하여 수행하였다. 또한 모의실험을 통하여 (s=2, T=2)인 경우가 MLC 부호기의 최적 연결다항식임을 알았다.

• 대한기계학회논문집B
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• 제21권2호
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• pp.202-212
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• 1997

In this study, performance of the multi-stage explicit methods for numerical computation of the unsteady Navier-Stokes equations is investigated. Three methods under consideration are 1 st-, 2 nd-, and 4 th-order Runge-Kutta (R-K) methods. Compared in this estimation is stability, accuracy, and CPU time of each method. The computational codes developed are applied to the two-dimensional flow in a square cavity driven by an oscillating lid. It turned out that at Reynolds number 400, the 1 st-order R-K method is the best, while at 3200 the 2 nd-order R-K is recommended. At higher Reynolds numbers, it is conjectured that the 4 th-order R-K method will be the best algorithm among three due to its highest stability.

• ETRI Journal
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• 제39권3호
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• pp.319-325
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• 2017

The decoding process of a quasi-cyclic low-density parity check code requires a unique type of rotator. These rotators, called multi-size cyclic-shifters (MSCSs), rotate input data with various sizes, where the size is the amount of data to be rotated. This paper proposes a low-complexity MSCS structure for the case when the sizes have a nontrivial common divisor. By combining the strong points of two previous structures, the proposed structure achieves the smallest area. The experimental results show that the area reduction was more than 14.7% when the proposed structure was applied to IEEE 802.16e as an example.

• 동력기계공학회지
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• 제5권2호
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• pp.93-99
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• 2001

This paper presents the automatic recognition system for car number plate. In our country, two types of number plate pattern is used. The one is old type of number plate, the other is new type of number plate. To recognize both new and old type number plates, the system must have flexibility. Therefore, in this paper, automatic recognition system is developed by use of the neural network for good adaptation, good generalization, and modulation. And because the number plate is made of three codes, the multi neural network consists of three networks. Neural network is teamed by GDR(Generalized Delta learning Rule) and it is verified the effectiveness of the method through experimental results.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.292-299
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• 2002

It has been realized that the design codes and underlying design concept of high seismicity region may not be appropriate to low and moderate seismicity regions. The aim of this paper is to search seismic design strategies that are appropriate to moderate seismicity regions. The characteristics of seismic hazard in moderate seismicity regions are reviewed. The seismic responses of multi-span continuous bridges subjected to the ground shaking of moderate intensity are examined. The present code on seismic design of bridges is briefly reviewed. Based on these observations, design principles and strategies appropriate to the moderate seismicity regions are proposed for the multi-span continuous bridge

• 인터넷정보학회논문지
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• 제7권1호
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• pp.173-178
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• 2006

본 논문에서는 OFDM-CDMA기반의 광대역 무선 접속시스템에서 다중 안테나를 적용한다. 이로서 시간영역에서 윈도우 기반의 채널추정 기법과 OFDM기반의 공간영역에서 다중 안테나 전송시스템에서 채널추정의 불완전성을 극복하기 위한 다채널 분리용 프리앰블을 적용함으로서 광대역 무선 접속시스템에서 사용자수를 최대로 확대하고 사용자 용량을 증대하는 광대역 무선접속시스템의 성능을 분석하였다.

• 한국통신학회논문지
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• 제24권7A호
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• pp.939-946
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• 1999

다중 사용자 환경의 이동통신 시스템에서 채널의 사용효율을 높이기 위해 학습 신호열을 사용하지 않고 채널을 추정할 수 있는 블라인드 채널 추정기법을 제안한다. 제안한 기법은 수신신호의 2차 통계특성과 부공간 개념을 이용하여 사용자들의 확산코드를 제외한 실제 물리적인 통신 채널만을 추정함으로써 계산량을 줄일 수 있는 장점을 가지고 있다. 모든 사용자들의 채널을 추정하기 위해 다중 채널 모델을 사용하여 비동기 DS-CDMA 시스템에서의 블라인드 기법을 유도하고 모의 실험을 통해 기존 방법에 비해 매우 적은 계산량을 요구하면서 비슷한 성능을 보임을 확인할 수 있었다.

• 제어로봇시스템학회논문지
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• 제11권4호
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• pp.297-303
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• 2005

In this paper, I developed an intelligent multi agents based softPLC(IMPLC). In IMPLC, the standard IEC 1131-3 PLC languages(LD, SFC, FBD, ST) programmed by a user are converted to IL, which is one of intermediate codes, in order to make them interactions. And then the IL is converted to the standard C code regarding some extension and transplanting, which can be used in a commercial editor such as visual C++. In IMPLC, the logical errors and syntax errors occurred by users are detected, so that the optimal PC control based softPLC can be possible. IMPLC provide easy programming platform to such beginner as well as professionals. The study of code conversion is firstly tried in the world as well as KOREA. I applied IMPLC to 3 steps conveyer belt system. The simulation results say that the debugging steps by IMPLC using multi agents are decreased than the conventional softPLC's.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.535-539
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• 2008

Recently mobile devices can transmit mass data contained multi-media contents. According these flow, a demand for fast data transmission is being risen, so we acutely require remarkable technology that overcome mobile communication's poor environment and rise data transmission volume. Because it can be satisfied these needs, the OFDM(Orthogonal Frequency Division Multiplexing) that rise data transmission volume using efficient frequency, and MIMO(Multiple Input Multiple Output) that rise transmission confidence and data transmission volume using numbers of antenna is attended. Before design of MIMO-OFDM System we want to make an analysis for theory of its systems, and we want to design MIMO-OFDM simulator for verify an ability of modulation, data volume and numbers of antenna.

• Nuclear Engineering and Technology
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• 제49권6호
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• pp.1339-1345
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• 2017

In the framework of the EU funded project NURESAFE, the subchannel code CTF and the neutronics code DYN3D were integrated and coupled on the NURESIM platform. The developments achieved during this 3-year project include assembly-level and pin-by-pin multiphysics thermal hydraulics/neutron kinetics coupling. In order to test this coupling, a PWR rod ejection transient was simulated on a MOX/UOX minicore. The transient is simulated using two different models of the minicore. In the first simulation, both codes model the core with an assembly-wise resolution. In the second simulation, a pin-by-pin fuel-centered model is used in CTF for the central assembly, and a pin power reconstruction method is applied in DYN3D. The analysis shows the influence of the different models on global parameters, such as the power and the average fuel temperature, but also on local parameters such as the maximum fuel temperature.