• 수산해양기술연구
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• 제42권1호
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• pp.38-43
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• 2006

The 3-D modeling of ocean finite element method(OFEM) using $k-{\varepsilon}$ turbulent model and tetrahedron grids has been used to investigate the internal wave generation during the expansion of the deep water from the open sea to the shelf with a simple shape, which can be widely used in the fields of submarine development, ocean environment and meteorology, etc. In this paper, the detailed configuration of internal wave with its length and height and also the distribution of salinity and turbulent kinematic energy, etc. were derived. It is hoped that this OFEM method can be successfully applied to the numerical calculation of internal wave for and the oceanographic problems (tidal flows around underwater hill, plateau, Georges Bank, etc.) and ocean engineering problems(flow past artificial sea reefs) in future.

• Nonlinear Functional Analysis and Applications
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• 제28권3호
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• pp.623-646
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• 2023

In this article, we introduce the hyperbolic space version of a faster iterative algorithm. The proposed iterative algorithm is used to approximate the common fixed point of three multi-valued almost contraction mappings and three multi-valued mappings satisfying condition (E) in hyperbolic spaces. The concepts weak w²-stability involving three multi-valued almost contraction mappings are considered. Several strong and △-convergence theorems of the suggested algorithm are proved in hyperbolic spaces. We provide an example to compare the performance of the proposed method with some well-known methods in the literature.

• Nonlinear Functional Analysis and Applications
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• 제29권1호
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• pp.131-164
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• 2024

In this research, we study a modified relaxed Tseng method with a single projection approach for solving common solution to a fixed point problem involving finite family of τ-demimetric operators and a quasi-monotone variational inequalities in real Hilbert spaces with alternating inertial extrapolation steps and adaptive non-monotonic step sizes. Under some appropriate conditions that are imposed on the parameters, the weak and linear convergence results of the proposed iterative scheme are established. Furthermore, we present some numerical examples and application of our proposed methods in comparison with other existing iterative methods. In order to show the practical applicability of our method to real word problems, we show that our algorithm has better restoration efficiency than many well known methods in image restoration problem. Our proposed iterative method generalizes and extends many existing methods in the literature.

• 한국인터넷방송통신학회논문지
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• 제9권3호
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• pp.193-199
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• 2009

전력선 통신(PLC : Power Line Communication) 기술은 유선 액세스 네트워크 솔류션 중 높은 잠재력을 갖고 있는 후보로서 논의되고 있다. 본 논문에서는 PLC 채널에서 이중 이진 터보 부호(DBTC : Double Binary Turbo Code) 성능에 대해 연구하였다. PLC 채널 환경을 만들기 위해 Bernoulli-Gaussian 잡음을 고려하였다. 시스템 성능은 비트 오류 확률 측면에서 분석되었다. 실험 결과로부터 이중 이진 터보 부호화는 상당한 부호화 이득을 제공하는 것을 확인할 수 있었다. 또한 터보 복호 과정에서 복호 횟수를 증가시킴에 따라서 시스템 성능이 향상되는 것을 확인할 수 있었다.

• 한국통신학회논문지
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• 제29권10A호
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• pp.1147-1158
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• 2004

본 논문에서는 여러 STBC 기법들을 OFDM 시스템에 적용하여 STBC-OFDM 시스템을 설계하고 레일라이 페이딩 환경에서 채널추정 오차를 고려하여 각 시스템의 성능을 비교, 분석한다 먼저, 대표적인 STBC 방식들에 대한 시공간 부호화와 복조 알고리즘을 고찰한다. 또한, 이동통신 환경을 고려하여 OFDM 파라메타를 설정하고 전송율에 따라 QPSK, 8PSK, 16QAM, 64QAM, 256QAM 등의 변조방식을 선택할 수 있도록 STBC-OFDM 시스템을 설계하며 STBC-OFDM 시스템의 데이터 복조기와 채널 추정기의 구조를 제시한다. 끝으로, 레일라이 환경에서 전송율과 수신 안테나의 수에 따른 STBC-OFDM 시스템의 성능을 시뮬레이션을 통해 비교, 분석한다.