• 한국통신학회논문지
• /
• 제16권6호
• /
• pp.556-565
• /
• 1991

A가 nxn 삼중대각행렬인 선형방정식 Ax=b를 WZ분해 알고리즘을 이용하여 해석하고 이 알고리즘을 CAM Systolic Array 로 구현했다. 그리고 이 어레이를 평가하기위하여 LU분해 알고리즘을 제시하고 이를 W, D, Z분해 알고리즘과 비교 고찰한 결과 LU분해 알고리즘 보다 WZ분해 알고리즘이 1/4정도 가까운 시간으로 실행시간이 단축될 수 있었다. CAM Systolic Array에서 실행되는 각 단계를 1 time stpe으로 가정하면 2n+1 times이 필요하고 CAM의 데이타 워드는 메트릭스 원소의 값과 행번호, 연산의 형태 및 상태에 관한 정보를 포함하고 pipeline식으로 각 프로세서를 systolic processing하므로서 중앙제어가 필요없고, data brodcasting도 피할 수 있다.

• 한국연소학회지
• /
• 제6권2호
• /
• pp.29-35
• /
• 2001

Unsteady numerical study has been conducted on combustion dynamics of a lean-premixed swirl-stabilized gas turbine swirl injector. A three-dimensional computation method utilizing the message passing interface (MPI) parallel architecture, large eddy simulation(LES), and proper orthogonal decomposition (POD) technique was applied. The unsteady turbulent flame dynamics are simulated so that the turbulent flame structure can be characterized in detail. It was observed that some fuel lumps escape from the primary combustion zone, and move downstream and consequently produce hot spots. Those flame dynamics coincides with experimental data. In addition, basis modes of the unsteady turbulent flame are characterized using proper orthogonal decomposition (POD) analysis. The flame structure based on odd basis modes is apparently larger than that of even ones. The flame structure can be extracted from the summation of the basis modes and eigenvectors at any moment.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2013년도 하계학술대회
• /
• pp.221-222
• /
• 2013

본 논문에서는 채널상태에 기반하여 QRD-M (QR-decomposition based M algorithm)및 QRPIC (parallel interference cancellation using QR-decomposition)을 이용한 검출 기법을 제안한다. 기존의 QRD-M 검출기법은 성능은 좋지만 복잡도가 높고, QRPIC 기법은 성능은 떨어지지만 복잡도가 낮다. 제안된 검출 기법은 채널상태에 따라 QRD-M 검출 기법을 사용할지 QRPIC 검출 기법을 사용할지 결정하게 되므로 기존의 QRD-M 검출 기법보다 성능은 조금 감소하지만 복잡도가 크게 낮아진다.

• 한국전산유체공학회지
• /
• 제5권2호
• /
• pp.20-27
• /
• 2000

An unstructured implicit Euler solver is parallelized on a Cray T3E. Spatial discretization is accomplished by a cell-centered finite volume formulation using an upwind flux differencing. Time is advanced by the Gauss-Seidel implicit scheme. Domain decomposition is accomplished by using the k-way n-partitioning method developed by Karypis. In order to analyze the parallel performance of the solver, flows over a 2-D NACA 0012 airfoil and 3-D F-5 wing were investigated.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 1999년도 추계 학술대회논문집
• /
• pp.193-200
• /
• 1999

An unstructured implicit Euler solver is parallelized on a Cray T3E. Spatial discretization is accomplished by a cell-centered finite volume formulation using an unpwind flux differencing. Time is advanced by the Gauss-Seidel implicit scheme. Domain decomposition is accomplished by using the k-way N-partitioning method developed by Karypis. In order to analyze the parallel performance of the solver, flows over a 2-D NACA 0012 airfoil and a 3-D F-5 wing were investigated.

• 대한수학회보
• /
• 제44권4호
• /
• pp.795-806
• /
• 2007

We investigate F-traceless component of the conformal curvature tensor defined by (3.6) in $K\ddot{a}hler$ manifolds of dimension ${\geq}4$, and show that the F-traceless component is invariant under concircular change. In particular, we determine $K\ddot{a}hler$ manifolds with parallel F-traceless component and improve some theorems, provided in the previous paper([2]), which are concerned with the traceless component of the conformal curvature tensor and the spectrum of the Laplacian acting on $p(0{\leq}p{\leq}2)$-forms on the manifold by using the F-traceless component.

• 대한기계학회논문집A
• /
• 제27권4호
• /
• pp.647-655
• /
• 2003

This paper studies the observability of calibration system with a constraint movement by a constraint operator. The calibration system with the constraint movement need only simple sensing device to check whether the constraint movements are completed within an established range. However, it yields the concern about the poor parameter observability due to the constraint movements. This paper uses the QR-decomposition to find the optimal calibration configurations maximizing the linear independence of rows of a observation matrix. The number of identifiable parameters are examined by the rank of the observation matrix, which represents the parameter observability. The method is applied to a parallel typed machining center and the calibration results are presented. These results verify that the calibration system with low-cost indicators and simple planar table is accurate as well as reliable.

• 전자공학회논문지B
• /
• 제31B권12호
• /
• pp.81-90
• /
• 1994

This paper proposes a motphological fast reconstructive filter (FRF) using up/down sampling techniques for reconstructive opening and closing, and a parallel structure for fast multiresolution decomposition. Compuer simulation shows that, compared with the conventional RF, the proposed FRF can reduce the processing time up to 8 times while it maintains a similar performance in reconstructed shapes. Further reduction in the decomposition time achieved by the paralellized algorithm combined with the FRF, which can be applied in areas such as defect detection, image segmentation, pattern recognition, etc.

• Journal of Communications and Networks
• /
• 제13권1호
• /
• pp.63-69
• /
• 2011

In this paper, we propose a fixed-complexity sphere encoder (FSE) for multi-user multi-input multi-output (MU-MIMO) systems. The proposed FSE accomplishes a scalable tradeoff between performance and complexity. Also, because it has a parallel tree-search structure, the proposed encoder can be easily pipelined, leading to a tremendous reduction in the precoding latency. The complexity of the proposed encoder is also analyzed, and we propose two techniques that reduce it. Simulation and analytical results demonstrate that in a $4{\times}4$ MU-MIMO system, the proposed FSE requires only 11.5% of the computational complexity needed by the conventional QR decomposition with M-algorithm encoder (QRDM-E). Also, the encoding throughput of the proposed encoder is 7.5 times that of the QRDM-E with tolerable degradation in the BER performance, while achieving the optimum diversity order.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제15권3호
• /
• pp.1156-1173
• /
• 2021

In this paper, we propose a new joint precoder and postcoder design strategy to support multiple streams per user in multiuser multiple-input multiple-output (MIMO) systems. We propose two step precoding strategies using equal channel gain decomposition and block diagonalization at the transmitter. With the proposed precoder, the multiuser MIMO channel can be decomposed into multiple parallel channels with equal channel gain per user. After applying receive postcoder which is generated and sent by the transmitter, we can use ML based decoder per stream to achieve full receive diversity. Achievable sum rate bound and diversity performance of the proposed algorithm are presented with feedback signaling design and quantitative complexity analysis. Simulation results show that the proposed algorithm asymptotically approaches to the sum rate capacity of the MIMO broadcast channel while maintaining full diversity order.