• Journal of KIISE:Computer Systems and Theory
• /
• v.30 no.5_6
• /
• pp.213-222
• /
• 2003

Most existing algorithms adopt the forward mapping method that is based on vector representation. Problem of existing algorithms Is the exponential increase of memory usage with number of layers. This degrades the accuracy of the boundary pattern representation. Our method uses bitmap representation and does not require any additional post-processing for conversion of vector-form results to bitmap-form. A new and efficient algorithm is presented in this paper for the generation of hyperbolic patterns by means of backward mapping methods.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.11
• /
• pp.972-978
• /
• 2012

This paper discusses the parallelization of multifrontal solution method, widely used for finite element structural analyses, for a shared memory architecture. Multifrontal method is easier than other linear solution methods because the solution procedure implies that unknowns can be eliminated simultaneously. Two innovative ideas are introduced to achieve optimal solver performance on a shared memory computer. Those are pairing two frontal matrices and splitting the frontal matrix in order to reduce the temporal memory space required by independent computing tasks. Performance comparisons between original algorithm and proposed one prove that proposed method is more computationally efficient on current multicore machines.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.3
• /
• pp.1-10
• /
• 2010

As processor platforms are continuously moving toward wireless mobile systems, embedded mobile processors are expected to perform more and more powerful, and therefore the development of an efficient power management algorithm for these battery-operated mobile and handheld systems has become a critical challenge. It is well known that a memory system is a main performance limiter in the processor point of view. Although many DVFS studies have been considered for the efficient utilization of limited battery resources, recent works do not explicitly show the interaction between the processor and the memory. In this research, to properly reflect short/long-term memory access patterns of the embedded workloads in wireless mobile processors, we propose a memory buffer utilization as a new index of DVFS level prediction. The simulation results show that our solution provides 5.86% energy saving compared to the existing DVFS policy in case of memory intensive applications, and it provides 3.60% energy saving on average.

• Proceedings of the Korea Institute of Convergence Signal Processing
• /
• 2000.08a
• /
• pp.173-176
• /
• 2000

본 논문은 VHDL을 이용하여 1997년 국제 표준안으로 제정된 MPEG-2 AAC 복호화기의 각 모듈을 구현하였다. AAC 복호화기는 허프만 복호화, 역양자화, 고해상도 필터뱅크 등의 도구들이 필수적으로 사용된다. AAC 복호화기의 실시간 구현을 위해 각 도구들의 알고리즘을 분석하고, 하드웨어 개발에 알맞게 최적화하여 고속화와 적은 메모리를 사용하여 효율적으로 구현하였다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2015.10a
• /
• pp.1202-1204
• /
• 2015

디지털 선박에서는 선박 내의 각종 센서로부터 측정된 디지털 데이터에 대한 정확하고 에너지 효율적인 관리가 필요하다. 본 논문에서는 디지털 선박 내에 다수 개의 센서(온도, 습도, 조도, 음성 센서)를 배치하고 효율적인 입력 스트림 처리를 위해서 슬라이딩 윈도우 기반으로 다중 Support Vector Machine(SVM) 알고리즘을 이용하여 사전 분류(pre-clustering)한 후 요약된 정보를 해쉬 테이블로 관리하는 효율적인 처리 기법을 제안한다. 해쉬 테이블을 이용하여 다차원 스트림 데이터의 저장될 레코드 순서를 빠르게 찾아 저장 및 검색함으로서 처리 속도가 향상되고 메모리에 해쉬 테이블 만을 유지하면 되므로 메모리 사용량이 감소한다. 35,912개의 데이터 집함을 사용하여 실험한 결과 제안 기법의 정확도와 처리 성능이 향상되었다.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2002.05c
• /
• pp.495-500
• /
• 2002

3D 컴퓨터 그래픽스 분야에서 사용되는 표면모델은 일반적으로 매우 복잡하고 방대한 양의 다각형 조각들로 구성된다. 이러한 표면 모델들은 사실감을 높일 수 있지만 지나치게 많은 데이터 양으로 인해 많은 문제들을 야기시킬 수 있다. 따라서 모델의 원래 모양을 가능하면 유지하면서 방대한 양의 데이터를 효과적으로 감소시킬 수 있는 방법이 필요하다. 본 논문에서는 지역표면의 기하학적 특성을 잘 보존할 수 있는 에지 비용함수를 제안한다. 또한 병합에 기반 한 반복적인 에지 축약을 기본 연산으로 하는 표면 간략화 알고리즘을 구현한다. 병합에 기반 한 축약방법은 메모리를 효율적으로 사용할 수 있게 하여 실시간 데이터 전송을 요하는 응용 시스템에 매우 효과적으로 적용될 수 있다. 제안하는 알고리즘을 표면모델에 적용시켜 간략화를 수행 한 결과 기존의 알고리즘에 비해 높은 품질의 근사모델을 얻을 수 있었으며 원래 모델의 세부적인 모양을 잘 보존할 수 있었다.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.21 no.2
• /
• pp.206-211
• /
• 2011

In this paper, the evolutionary algorithm was specifically formulated for optimization with continuous parameter space. The proposal was motivated by the fact that the genetic algorithms have been most intensively reported for parameter identification problems with continuous search space. The difference of primary characteristics between genetic algorithms and the proposed algorithm, discrete or continuous individual representation has made different areas to which the algorithms should be applied. Results obtained by optimization of some well-known test functions indicate that the proposed algorithm is superior to genetic algorithms in all the performance, computation time and memory usage for continuous search space problems.

• Journal of KIISE:Computer Systems and Theory
• /
• v.31 no.1_2
• /
• pp.10-18
• /
• 2004

Quadtree, which is a hierarchical data structure, is a very important data structure to represent binary images. The linear quadtree representation as a way to store a quadtree is efficient to save space compared with other representations. Therefore, it has been widely studied to develop efficient algorithms to execute operations related with quadtrees. The operations of unaligned linear quadtrees, which are operations among the linear quadtrees with different origin, are able to perform the translated or rotated images efficiently. And this operations requires alignment of the linear quadtrees. In this paper, we present an efficient algorithm to perform alignment of unaligned linear quadtrees, using three-dimensional $n{\pm}n{\pm}n$ processors on RMESH(Reconfigurable MESH). This algorithm has constant-time complexity by using efficient basic operations to route the locational codes of quardtree on the hierarchical structure of $n{\pm}n{\pm}n$ RMESH.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.4B
• /
• pp.397-402
• /
• 2004

In this paper, we have designed and simulated a new file transmission method. This method restricts memory copy and context switching happened in traditional file transmission. This method shows an improved performance than traditional method in network environment. When the UNIX/LINUX system that uses the existing file transfer technique transmits a packet to the remote system, a memory copy between the user and kernel space occurs over twice at least. Memory copy between the user and kernel space increase a file transmission time and the number of context switching. As a result, the existing file transfer technique has a problem of deteriorating the performance of file transmission. We propose a new algorithm for solving these problems. It doesn't perform memory copy between the user and kernel space. Hence, the number of memory copy and context switching is limited to the minimum. We have modified the network related source code of LINUX kernel 2.6.0 to analyzing the performance of proposed algorithm and implement new network system calls.

• Journal of KIISE:Computer Systems and Theory
• /
• v.34 no.5_6
• /
• pp.238-248
• /
• 2007

As the demand of employing various PC software on mobile embedded devices which have limited storages has been increased, software streaming services are needed. However it takes too much time to launch software on them because it is transferred through wireless networks. To address this problem, prefetch algorithms are needed. We examined 'Last successor (LS)' algorithm and PPM-based prefetch algorithm as prefetch algorithms for software streaming services. We present 'Probability-base Multi Successor (PMS)' algorithm which is contrived through analyzing evaluations of previous algorithms and characteristics of software streaming services. While LS has one successor per each block, PMS has N successors based on probability which is calculated by PPM-based prefetch algorithm. The hit rate of PMS is similar to that of PPM-base prefetch algorithm and the space overhead is similar to that of LS. We can get good efficiency at the point of memory usage when PMS is applied to software streaming services.