• Journal of the Korean Association of Geographic Information Studies
• /
• v.4 no.4
• /
• pp.1-7
• /
• 2001

Remotely sensed data is the most fundamental data in acquiring the GIS informations, and may be analyzed to extract useful thematic information. Multi-spectral classification is one of the most often used methods of information extraction. The actual multi-spectral classification may be performed using either supervised or unsupervised approaches. This paper analyze the effect of assigning clever initial values to image classes on the performance of parallelepiped classification algorithm, which is one of the supervised classification algorithms. First, we investigate the effect on serial computing model, then expand it on MIMD(Multiple Instruction Multiple Data) parallel computing model. On serial computing model, the performance of the parallel pipe algorithm improved 2.4 times at most and, on MIMD parallel computing model the performance improved about 2.5 times as clever initial values are assigned to image class. Through computer simulation we find that initial values of image class greatly affect the performance of parallelepiped classification algorithms, and it can be improved greatly when classes on both serial computing model and MIMD parallel computation model.

• Proceedings of the IEEK Conference
• /
• 2002.07a
• /
• pp.58-61
• /
• 2002

In this paper, we present a new generalized k-Tree-based (CU/PE) allocation model to perform dynamic resource (CU/PE) allocation/deallocation decision for the reconfigurable MSIMD/MIMD multi-dimensional (k-D) mesh-connected architectures. Those reconfigurable multi-SIMD/MIMD systems allow dynamic modes of executing tasks, which are SIMD and MIMD. The MIMD task requires only the free sub-system; however the SIMD task needs not only the free sub-system but also the corresponding free CU. In our new k-Tree-based (CU/PE) allocation model, we introduce two best-fit heuristics for the CU allocation decision: 1) the CU depth first search (CU-DFS) in O(kN$_{f}$ ) time and 2) the CU adjacent search (CU-AS) in O(k2$^{k}$ ) time. By the simulation study, the system performance of these two CU allocation strategies was also investigated. Our simulation results showed that the CU-AS and CU-DFS strategies performed the same system performance when applied for the reconfigurable MSIMD/MIMD 2-D and 3-D mesh-connected architectures.

• Journal of Digital Contents Society
• /
• v.12 no.3
• /
• pp.299-307
• /
• 2011

The MAC of IEEE 802.11 WLAN to control data transmission uses two control methods called DCF and PCF. The DCF controls the transmission based on CSMA/CA The BEB backoff algorithm of DCF shows relatively excellent performance in situation that the number of competing station is less, but has a problem that performance of throughput and delay is degraded in situation that the number of competing station is increased. This paper mathematically analyzes an MIMD backoff algorithm considering retry limit that increases the CW to doubled after collision and decreases smoothly the CW to halves after successful transmission in order to reduce the collision probability. To prove efficiency of the MIMD backoff algorithm, lots of simulations are conducted and analyzed.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.31B no.12
• /
• pp.1-10
• /
• 1994

In this paper, we propose a processor allocation algorithm using the PGG(Packed Gray code Group) for the MIMD hypercube. The number of k-D subcubes in an n-cube is C(n.k) en-k. When the PGG is employed in the processor allocation, C(n, k) PGG's are required to recognize all the k-D subcubes in an n-cube. from the simulation we find that the capability of processor allocation using only 40% of C(n, k) PGG's is about the same as that of the allocation using all the PGG's.

• The KIPS Transactions:PartA
• /
• v.8A no.1
• /
• pp.9-15
• /
• 2001

영상에 관련된 다양한 응용 시스템들을 구현하는 많은 연구들이 진행되어 왔지만, 그러한 영상 관련 응용 시스템을 구현함에 있어서 처리속도의 저하로 인하여 많은 어려움을 겪고 있다. 이를 해결하기 위해 대두된 여러 방법들 중에서 최근 하드웨어 접근 방법에 고려한 많은 관심과 연구가 진행되고 있다. 본 논문은 영상을 실시간으로 처리하기 위하여 하드웨어 구조를 갖는 병렬처리시스템을 기술하며, 또한 병렬처리시스템을 얼굴 검색 시스템에 적용한 후 처리속도 및 실험 결과를 기술한다. 병렬처리시스템은 SIMD와 MIMD가 결합된 구조를 갖고 있기 때문에 다양한 영상 응용시스템에 대해서 융통성과 효율성을 제공하며, 144개의 처리기와 12개의 다중접근기억장치, 외부 메모리 모듈을 위한 인터페이스와 외부 프로세서 장치(i960Kx)와의 통신을 위한 인터페이스로 구성되어있다. 다중접근기억장치는 메모리 모듈선택회로, 데이터 라이팅회로, 그리고, 주소계산 및 라우팅회로로 구성되어 있다. 또한 얼굴 검색 시스템을 병렬처리 시스템에 적합한 병렬화를 제공하기 위해 메쉬방법을 이용하여 전처리, 정규화, 4개 특징값 추출, 그리고 분류화로 구성하였다. 병렬처리시스템은 하드웨어 모의실험 패키지인 CADENCE사의 Verilog-XL로 모의실험을 수행하여 기능과 성능을 검증하였다.

• Journal of Korea Society of Industrial Information Systems
• /
• v.3 no.1
• /
• pp.258-268
• /
• 1998

This paper presents two sequential advanced split and merge algorithms and a parallel image segmentation algorithm based on them. First, the two advanced methods are obtained from the combination of edge detection and classic split and merge to solve the inherent problems of the classical method. Besides, the parallel image segmentation algorithm on mesh-connected MIMD system considers three types in the merge stage to reduce the communication overhead between processors, such as intraprocessor merge, interprocessor with boundary merge, and interprocessor without boundary merge. Finally , we prove that the proposed algorithms achieve the improved performance by implementing them.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.29B no.10
• /
• pp.1-9
• /
• 1992

This paper presents an effective synchronization algorithm. It is different from the existing synchronization methods by inserting appropriate synchronization instructions between statements according to different kinds of data dependencies. The overhead caused by too many synchronization instructions in a loop can be a critical problem. Synchronization optimization is a method which discriminates and eliminates the redundant synchronization instructions in a loop. In this paper, a new synchronization optimization algorithm is developed, and performance analysis using simulation on the UNIX operating system is carried out.

• The Transactions of the Korea Information Processing Society
• /
• v.2 no.2
• /
• pp.148-155
• /
• 1995

When we analize many amount of patterns, it is necessary for these patterns are to be clustering into several groups according to a certain evaluation function. This process, in case that there are lots of input patterns, needs a considerable amount of computations and is reqired parallel algorithm for these. To solve this problem, this paper propose parallel clustering algorithm which parallelized k-means algorithm and implemented it under the MIMD parallel computer based message passing. The result is through the experiment and performance analysis, that this parallel algorithm is appropriate in case these are many input patterns.

• The Journal of the Acoustical Society of Korea
• /
• v.18 no.5
• /
• pp.44-51
• /
• 1999

This paper presents a massively parallel computational model for the efficient integration of speech and natural language understanding. The phoneme model is based on continuous Hidden Markov Model with context dependent phonemes, and the language model is based on a knowledge base approach. To construct the knowledge base, we adopt a hierarchically-structured semantic network and a memory-based parsing technique that employs parallel marker-passing as an inference mechanism. Our parallel speech recognition algorithm is implemented in a multi-Transputer system using distributed-memory MIMD multiprocessors. Experimental results show that the parallel speech recognition system performs better in recognition accuracy than a word network-based speech recognition system. The recognition accuracy is further improved by applying code-phoneme statistics. Besides, speedup experiments demonstrate the possibility of constructing a realtime parallel speech recognition system.

• Proceedings of the Korean Information Science Society Conference
• /
• 1998.10a
• /
• pp.747-749
• /
• 1998

본 논문에서는 음성과 자연언어의 통합처리를 위한 효과적인 병렬 계산 모델을 제안한다. 음소모델은 continuous HMM에 기반을 둔 문맥종속형 음소를 사용하며, 언어모델은 knowledge-based approach를 사용한다. 또한 계층구조의 지식베이스상에서 다수의 가설을 처리하기 위해 memory-based parsing기술을 사용하였다. 본 연구의 병렬 음성인식 알고리즘은 분산메모리 MIMD 구조의 다중 Transputer 시스템을 이용하여 구현되었다. 실험을 통하여 음성인식 과정에서 발생하는 speech-specific problem의 해를 제공하고 음성인식 시스템의 병렬화를 통하여 실시간 음성인식의 가능성을 보여준다.