• Title/Summary/Keyword: Computation process

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Two-dimensional DCT arcitecture for imprecise computation model (중간 결과값 연산 모델을 위한 2차원 DCT 구조)

  • 임강빈;정진군;신준호;최경희;정기현
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.34C no.9
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    • pp.22-32
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    • 1997
  • This paper proposes an imprecise compuitation model for DCT considering QOS of images and a two dimensional DCT architecture for imprecise computations. In case that many processes are scheduling in a hard real time system, the system resources are shared among them. Thus all processes can not be allocated enough system resources (such as processing power and communication bandwidth). The imprecise computtion model can be used to provide scheduling flexibility and various QOS(quality of service)levels, to enhance fault tolerance, and to ensure service continuity in rela time systems. The DCT(discrete cosine transform) is known as one of popular image data compression techniques and adopted in JPEG and MPEG algorithms since the DCT can remove the spatial redundancy of 2-D image data efficiently. Even though many commercial data compression VLSI chips include the DCST hardware, the DCT computation is still a very time-consuming process and a lot of hardware resources are required for the DCT implementation. In this paper the DCT procedure is re-analyzed to fit to imprecise computation model. The test image is simulated on teh base of this model, and the computation time and the quality of restored image are studied. The row-column algorithm is used ot fit the proposed imprecise computation DCT which supports pipeline operatiions by pixel unit, various QOS levels and low speed stroage devices. The architecture has reduced I/O bandwidth which could make its implementation feasible in VLSI. The architecture is proved using a VHDL simulator in architecture level.

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Tabu Search-Genetic Process Mining Algorithm for Discovering Stochastic Process Tree (확률적 프로세스 트리 생성을 위한 타부 검색 -유전자 프로세스 마이닝 알고리즘)

  • Joo, Woo-Min;Choi, Jin Young
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.42 no.4
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    • pp.183-193
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    • 2019
  • Process mining is an analytical technique aimed at obtaining useful information about a process by extracting a process model from events log. However, most existing process models are deterministic because they do not include stochastic elements such as the occurrence probabilities or execution times of activities. Therefore, available information is limited, resulting in the limitations on analyzing and understanding the process. Furthermore, it is also important to develop an efficient methodology to discover the process model. Although genetic process mining algorithm is one of the methods that can handle data with noises, it has a limitation of large computation time when it is applied to data with large capacity. To resolve these issues, in this paper, we define a stochastic process tree and propose a tabu search-genetic process mining (TS-GPM) algorithm for a stochastic process tree. Specifically, we define a two-dimensional array as a chromosome to represent a stochastic process tree, fitness function, a procedure for generating stochastic process tree and a model trace as a string of activities generated from the process tree. Furthermore, by storing and comparing model traces with low fitness values in the tabu list, we can prevent duplicated searches for process trees with low fitness value being performed. In order to verify the performance of the proposed algorithm, we performed a numerical experiment by using two kinds of event log data used in the previous research. The results showed that the suggested TS-GPM algorithm outperformed the GPM algorithm in terms of fitness and computation time.

Finite Element Analysis of Auto-body Panel Stamping (리어 힌지 패널 스템핑의 유한요소해석)

  • 정동원;이장희;양동열
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1996.06a
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    • pp.97-109
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    • 1996
  • In the present work computations are carried out for analysis of complicated sheet metal forming process such as forming of a rear hinge. Finite element formulation using dynamic explicit time integration scheme and step-wise combined Implicit/Explicit scheme are introduced for numerical analysis of sheet metal forming process. The rigid-plastic finite element method based on membrane elements has long been employed as a useful numerical technique for the analysis of sheet metal forming because of its time effectiveness. The explicit scheme in general use is based on the elastic-plastic modelling of material requiring large computation time. In finite element simulation of sheet metal forming processes, the robustness and stability of computation are important requirements since the computation time and convergency become major points of consideration besides the solution accuracy due to the complexity of geometry and boundary conditions. The implicit scheme employs a more reliable and rigorous scheme in considering the equilibrium at each step of deformation, while in the explicit scheme the problem of convergency is eliminated at the cost of solution accuracy. The explicit approach and the implicit approach have merits and demerits, respectively. In order to combine the merits of these two methods a step-wise combined implicit/explicit scheme has been developed.

Numerical Simulation of Incipient Breaking Waves (초기 쇄파의 수치모사)

  • 김용직;김선기
    • Journal of the Society of Naval Architects of Korea
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    • v.39 no.4
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    • pp.1-10
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    • 2002
  • For the time-domain simulation of incipient breaking waves, usually the boundary integral method has been used so far, and it seems to be successful except a problem of too much computation time. The present paper shows a new computation technique for the simulation of breaking wave experiment. This technique uses the high-order spectral/boundary element method and the boundary integral method in sequence, and reduces the computation time remarkably. The wave generation and energy focusing process is efficiently simulated by the high-order spectral/boundary element method. Only the wave over-turning process is simulated by the boundary integral method. In the example calculation result, salient features of breaking waves such as high particle velocities and accelerations are shown.

Optimal Control of Large-Scale Dynamic Systems using Parallel Processing (병렬처리를 이용한 대규모 동적 시스템의 최적제어)

  • Park, Ki-Hong
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.4
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    • pp.403-410
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    • 1999
  • In this study, a parallel algorithm has been developed that can quickly solve the optiaml control problem of large-scale dynamic systems. The algorithm adopts the sequential quadratic programming methods and achieves domain decomposition-type parallelism in computing sensitivities for search direction computation. A silicon wafer thermal process problem has been solved using the algorithm, and a parallel efficiency of 45% has been achieved with 16 processors. Practical methods have also been investigated in this study as a way to further speed up the computation time.

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Finite element analysis of welding process by parallel computation (병렬 처리를 이용한 용접 공정 유한 요소 해석)

  • 임세영;김주완;최강혁;임재혁
    • Proceedings of the KWS Conference
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    • 2003.11a
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    • pp.156-158
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    • 2003
  • An implicit finite element implementation for Leblond's transformation plasticity constitutive equations, which are widely used in welded steel structure is proposed in the framework of parallel computing. The implementation is based upon the multiplicative decomposition of deformation gradient and hyper elastic formulation. We examine the efficiency of parallel computation for the finite element analysis of a welded structure using domain-wise multi-frontal solver.

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Application for parallel computation for finite element analysis of welding processes (용접공정 유한요소 해석의 병렬 처리 적용)

  • 임세영;김주완;최강혁
    • Proceedings of the KWS Conference
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    • 2004.05a
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    • pp.273-275
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    • 2004
  • A parallel multi-frontal solver is developed for finite element analysis of an arc-welding process, which entails phase evolution, heat transfer, and deformations of structure. We verify the code via comparison to a commercial code,SYSWELD. Attention is focused on the implementation of the parallel solver using MPI library, on the speedup by parallel computation, and on the effectiveness of the solver in welding application

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The syntax of Linear logic (선형논리의 통사론)

  • Cheong, Kye-Seop
    • Journal for History of Mathematics
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    • v.25 no.3
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    • pp.29-39
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    • 2012
  • As a product of modern proof theory, linear logic is a new form of logic developed for the purpose of enhancing programming language by Professor Jean-Yves Girard of Marseille University (France) in 1987 by supplementing intuitionist logic in a sophisticated manner. Thus, linear logic' s connectives can be explained using information processing terms such as sequentiality and parallel computation. For instance, A${\otimes}$B shows two processes, A and B, carried out one after another. A&B is linked to an internal indeterminate, allowing an observer to select either A or B. A${\oplus}$B is an external indeterminate, and as such, an observer knows that either A or B holds true, but does not know which process will be true. A ${\wp}$ B signifies parallel computation of process A and process B; linear negative exhibits synchronization, that is, in order for the process A to be carried out, both A and $A^{\bot}$ have to be accomplished simultaneously. Since the field of linear logic is not very active in Korea at present, this paper deals only with syntax aspect of linear logic in order to arouse interest in the subject, leaving semantics and proof nets for future studies.

A Bayesian Approach for Record Value Statistics Model Using Nonhomogeneous Poisson Process

  • Kiheon Choi;Hee chual Kim
    • Communications for Statistical Applications and Methods
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    • v.4 no.1
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    • pp.259-269
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    • 1997
  • Bayesian inference for a record value statistics(RVS) model of nonhomogeneous Poisson process is considered. We seal with Bayesian inference for double exponential, Gamma, Rayleigh, Gumble RVS models using Gibbs sampling and Metropolis algorithm and also explore Bayesian computation and model selection.

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Evolutionary computation approach for automated synthesis design of mechanical structures (기계 구조의 합성적 자동생성을 위한 진화연산)

  • 이인호;차주헌;김재정
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.643-646
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    • 2002
  • This paper proposes an evolutionary computation approach for automated design of mechanical structures especially in its early stage of design phases. Due to the known characteristics of the stage, the approach basically involves a synthetic design method with the composition of building blocks representing the elements of mechanical objects. In order for the building blocks to be more suitable for representation and evolution of mechanical structures, Elementary Cell Blocks (ECBs) are introduced as new building blocks. A new Darwinian evolution process for the new building blocks is also necessarily involved in the approach. We have demonstrated the implementation of the approach with the design of multi-step gear systems.

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