• 한국통신학회논문지
• /
• 제26권11C호
• /
• pp.94-101
• /
• 2001

본 논문에서는 기존의 smoothing scheme의 문제점을 개선한 향상된 WRR 셀 스케줄링 알고리즘을 제안하였다. 제안된 셀 스케쥴링 알고리즘에서는 각 VC 큐에 실제로 입력된 멀티미디어 셀의 개수, 가중치 및 큐의 상태를 나타내는 변수를 사용하여, 가중치를 초과하여 셀이 입력된 버퍼와 가중치보다 셀이 적게 입력된 버퍼의 VC를 효율적으로 서비스할 수 있도록 하였다. 그리고, 실시간 트래픽에 할당하고 남은 대역을 비실시간 트래픽에 제공함으로써 멀티미디어 서비스가 가능하도록 하여 서비스되는 평균 셀의 개수를 증가시키고, 버퍼의 길이를 감소시킬 수 있도록 하였다. 컴퓨터 시뮬레이션을 통하여 제안된 알고리즘의 성능을 평가하였으며, 그 결과 만족할만한 성능을 확인하였다.

• Nuclear Engineering and Technology
• /
• 제56권7호
• /
• pp.2498-2515
• /
• 2024

In this study, we propose a fully parallelized adaptive particle refinement (APR) algorithm for smoothed particle hydrodynamics (SPH) to construct a stable and efficient multi-resolution computing system for nuclear safety analysis. The APR technique, widely employed by SPH research groups to adjust local particle resolutions, currently operates on a serialized algorithm. However, this serialized approach diminishes the computational efficiency of the system, negating the advantages of acceleration achieved through high-performance computing devices. To address this drawback, we propose a fully parallelized APR algorithm designed to enhance both efficiency and computational accuracy, facilitated by a new adaptive smoothing length model. For model validation, we simulated both hydrostatic and hydrodynamic benchmark cases in 2D and 3D environments. The results demonstrate improved computational efficiency compared to the conventional SPH method and APR with a serialized algorithm, and the model's accuracy was confirmed, revealing favorable outcomes near the resolution interface. Through the analysis of jet breakup, we verified the performance and accuracy of the model, emphasizing its applicability in practical nuclear safety analysis.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.510-513
• /
• 2005

Due to the asymptotic property, deadbeat control can hardly be applied to the continuous time system control. But some delay element method can deal such a problem. Besides delay element method, well-known digital deadbeat control can be used by the aid of some smoothing elements. In this paper, 2nd order smoothing element is used for the smoothing of the digital deadbeat controller. And this element is argumented to the plant, and so control problem is to control the argumented system digitally. We simulated this control system using Matlab language and finally apply this algorithm to the rotary inverted pendulum system.

• 융합신호처리학회논문지
• /
• 제3권1호
• /
• pp.21-26
• /
• 2002

비디오 스트림들은 사용된 압축 알고리듬의 구조와 화면의 복잡도 등에 따라 다양한 형태의 트래픽이 발생함으로, 송신측과 수신측 사이의 자원할당을 어렵게 할 뿐만 아니라, 현재의 인터넷과 같은 패킷 통신망에서는 연속적인 재생을 어렵게 한다. 따라서, 본 논문에서는 멀티스트림을 이용한 비디오 스트림의 평활화 방법을 제안한다. 제안한 방법은 스트림의 형태에 따라 LDU(logical data unit)를 정의한 후 일정한 크기로 다수의 스트림으로 생성하여 전송함으로써, 평활화와 선반입 과정에서 발생하는 버퍼링 시간을 줄일 수 있을 뿐만 아니라 네트워크의 지터에도 강하면, 클라이언트의 대역폭을 최대한 활용할 수 있는 효율적인 전송 특성을 얻을 수 있다.

• 조명전기설비학회논문지
• /
• 제18권6호
• /
• pp.108-113
• /
• 2004

점근특성 때문에 deadbeat제어는 연속계시스템에는 거의 적용이 불가능하다. 그러나 지연요소법은 이런 문제를 해결할 수 있다. 지연요소법외에도 잘 알려진 디지털 deadbeat제어가 평활요소를 추가하여 사용될 수 있다. 본 논문에서는 2차 평활요소를 디지털 deadbeat제어기에 사용한다. 그리고 이 요소는 플랜트에 확장되고 따라서 확장된 시스템을 디지털제어하게 된다. 이 제어시스템을 Matlab언어를 사용하여 회전형 도립진자 시스템에 적용하여 시뮬레이션한다.

• 전기학회논문지
• /
• 제63권4호
• /
• pp.451-454
• /
• 2014

Short-term load forecasting(STLF) for electric power demand is essential for stable power system operation and efficient power market operation. We improved STLF method by using hourly temperature as an input data. In order to using hourly temperature to STLF algorithm, we calculated temperature-electric power demand sensitivity through past actual data and combined this sensitivity to exponential smoothing method which is one of the STLF method. The proposed method is verified by case study for a week. The result of case study shows that the average percentage errors of the proposed load forecasting method are improved comparing with errors of the previous methods.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 추계학술대회논문집
• /
• pp.159-162
• /
• 2003

The remeshing algorithm using the constrained Delaunay method adapted to the mesh density map is developed. In the finite element simulation of forging process, the numerical error increases as the process goes on. However, it is not desirable to use a uniformly fine mesh in the whole domain. Therefore, it is necessary to reduce the analysis error by constructing locally fine mesh at the region where the error is concentrated such as die corner. In this paper, the point insertion algorithm is used and mesh size is controlled by using a mesh density map constructed with a posteriori error estimation. And an optimized smoothing technique is adapted to have smooth distribution and improve the quality of the mesh.

• Journal of Advanced Marine Engineering and Technology
• /
• 제21권1호
• /
• pp.66-70
• /
• 1997

In this paper a new learning algorithm for curvature smoothing and improved generalization for multi-layer neural networks is proposed. To enhance the generalization ability a constraint term of hidden neuron activations is added to the conventional output error, which gives the curvature smoothing characteristics to multi-layer neural networks. When the total cost consisted of the output error and hidden error is minimized by gradient-descent methods, the additional descent term gives not only the Hebbian learning but also the synaptic weight decay. Therefore it incorporates error back-propagation, Hebbian, and weight decay, and additional computational requirements to the standard error back-propagation is negligible. From the computer simulation of the time series prediction with Santafe competition data it is shown that the proposed learning algorithm gives much better generalization performance.

• International Journal of Aeronautical and Space Sciences
• /
• 제3권2호
• /
• pp.88-94
• /
• 2002

This paper describes attitude determination algorithm for the low earth orbit(LEO) spacecraft using stellar inertial sensors. The cascaded gyro/star tracker extended Kalman filter is constructed to fuse two sensor data. And then the smoothing of the measurement are proposed for an unreasonable jump of star tracker. The smoothing algorithm for the rejection of star tracker error jumps is designed by scalar adaptive filter. The proposed algorithms operate to process the measurement of gyro/star tracker Kalman filter, therefore, it is comparatively simple to apply these methods to other integration systems. Simulations to gyro/star tracker integrated system show that the proposed method is effective.

• 소성∙가공
• /
• 제13권4호
• /
• pp.334-341
• /
• 2004

In this study, a remeshing algorithm adapted to the mesh density map using the Delaunay mesh generation method is developed. In the finite element simulation of forging process, the numerical error increases as the process goes on because of discrete property of the finite elements and distortion of elements. Especially, in the region where stresses and strains are concentrated, the numerical error will be highly increased. However, it is not desirable to use a uniformly fine mesh in the whole domain. Therefore, it is necessary to reduce the analysis error by constructing locally refined mesh at the region where the error is concentrated such as at the die corner. In this paper, the point insertion algorithm is used and the mesh size is controlled by using a mesh density map constructed with a posteriori error estimation. An optimized smoothing technique is adopted to have smooth distribution of the mesh and improve the mesh element quality.