• Title/Summary/Keyword: Loop Transformation

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A Loop Transformation for Parallelism from Single Loops

  • Jeong, Sam-Jin
    • International Journal of Contents
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    • v.2 no.4
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    • pp.8-11
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    • 2006
  • This paper describes several loop partitioning techniques such as loop splitting method by thresholds and Polychronopoulos' loop splitting method for exploiting parallelism from single loop which already developed. We propose improved loop splitting method for maximizing parallelism of single loops with non-constant dependence distances. By using the distance for the source of the first dependence, and by our defined theorems, we present generalized and optimal algorithms for single loops with non-uniform dependences. The algorithms generalize how to transform general single loops into parallel loops.

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Comparison of Recurrence Rates with Contour-Loop Excision of the Transformation Zone (C-LETZ) and Large Loop Excision of the Transformation Zone (LLETZ) for CIN

  • Boonlikit, Sathone;Srichongchai, Hemwadee
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.15
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    • pp.6005-6008
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    • 2014
  • Aim: To compare recurrence rates of large loop excision of the transformation zone (LLETZ) with those of contour-loop excision of the transformation zone (C-LETZ) in the management of cervical intraepithelial neoplasia (CIN). Materials and Methods: The medical records of 177 patients treated consecutively by LLETZ and C-LETZ for CIN at Rajavithi Hospital between 2006 and 2009 were retrospectively reviewed. Results: Of the 87 women in the C-LETZ group, 2 cases (2.30%) had recurrence compared with 13 cases (14.4%) of the 90 women in the LLETZ group, the higher recurrence rate in the latter being statistically significant (p<0.05). Median times of follow up in the C-LETZ and LLETZ groups were 12 months and 14 months respectively (p>0.05). The C-LETZ group showed less intraoperative bleeding compared to the LLETZ group, but the rate of achievement of single specimens and positive margins were similar in the two groups. Conclusions: The present study demonstrated the superiority of C-LETZ over LLETZ in terms of efficacy; C-LLETZ is associated with a lower recurrence rate and also carries a smaller risk of intraoperative bleeding than LLETZ. The rotating technique still has a potential role in treating precancerous lesions of the cervix.

Motion Control on Animation Space (애니메이션 공간에서의 제어의 통한 동작 생성)

  • Park, Ji-Heon;Park, Seong-Heon
    • The KIPS Transactions:PartA
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    • v.8A no.2
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    • pp.167-178
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    • 2001
  • This paper presents a new methodology for specification and control of the motion of an articulated rigid body for the purposes of animation by coordinate transformations. The approach is to formulate the problem as a coordinate transformation from the joint space of the body to a user-defined animation space which is chosen for convenience in constraining the motion. Constraints are applied to the resulting coordinate transformation equations. It is sufficiently general so that it can be applied to all common types of control problems, including closed loop as well as open loop mechanisms. We also provided a new approach to simulate a closed loop mechanism, which is using animation space transformation technique. The method is formulated in detail and is demonstrated by animating the motion of an inchworm.

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A Program Restructuring framework for Parallel Processing (병렬처리를 위한 프로그램 재구조화)

  • 송월봉
    • Journal of the Korea Computer Industry Society
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    • v.4 no.4
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    • pp.501-508
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    • 2003
  • In this paper A new theory of linear loop transformation called Elimination of Data Dependency(BDD) is presented. The current framework of linear loop transformation cannot identify a significant fraction of parallelism. For this reason, a method to extract the maximum loop parallelism in perfect nested loops is presented. This technique is applicable to general loop nests where the dependence include both distance and directions.

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The Procedure Transformation using Data Dependency Elimination Methods (자료 종속성 제거 방법을 이용한 프로시저 변환)

  • Jang, Yu-Suk;Park, Du-Sun
    • The KIPS Transactions:PartA
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    • v.9A no.1
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    • pp.37-44
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    • 2002
  • Most researches of transforming sequential programs into parallel programs have been based on the loop structure transformation method. However, most programs have implicit interprocedure parallelism. This paper suggests a way of extracting parallelism from the loops with procedure calls using the data dependency elimination method. Most parallelization of the loop with procedure calls have been conducted for extracting parallelism from the uniform code. In this paper, we propose interprocedural transformation, which can be apply to both uniform and nonuniform code. We show the examples of uniform, nonuniform, and complex code parallelization. We then evaluated the performance of the various transformation methods using the CRAY-T3E system. The comparison results show that the proposed algorithm out-performs other conventional methods.

Locality-Conscious Nested-Loops Parallelization

  • Parsa, Saeed;Hamzei, Mohammad
    • ETRI Journal
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    • v.36 no.1
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    • pp.124-133
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    • 2014
  • To speed up data-intensive programs, two complementary techniques, namely nested loops parallelization and data locality optimization, should be considered. Effective parallelization techniques distribute the computation and necessary data across different processors, whereas data locality places data on the same processor. Therefore, locality and parallelization may demand different loop transformations. As such, an integrated approach that combines these two can generate much better results than each individual approach. This paper proposes a unified approach that integrates these two techniques to obtain an appropriate loop transformation. Applying this transformation results in coarse grain parallelism through exploiting the largest possible groups of outer permutable loops in addition to data locality through dependence satisfaction at inner loops. These groups can be further tiled to improve data locality through exploiting data reuse in multiple dimensions.

An Efficient Loop Splitting Method on Single Loop with Non-uniform Dependences (비균일 단일루프에서의 효율적인 루프 분할 방법)

  • Jeong Sam-Jin
    • The Journal of the Korea Contents Association
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    • v.5 no.4
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    • pp.204-211
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    • 2005
  • This paper introduces three loop splitting methods such as minimum dependence distance method, Polychronopoulous' method, and first dependence method for exploiting parallelism from single loop which already developed. And it also Indicates their several problems. We extend the first dependence method which is the most effective one among three loop splitting methods, and propose more powerful loop splitting method to enhance parallelism on single loop. The proposed algorithm solves several problems, such as anti-flow dependence and g=gcd(a,c) > 1, that the first dependence method has.

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Power-conscious high level synthesis using loop folding (루프의 중첩을 이용한 저전력 상위 수준 합성)

  • 김대홍;최기영
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.34C no.6
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    • pp.1-10
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    • 1997
  • By considering low power design at higher levels of abstraction rather than at lower levels of abstraction, we can apply various transformation techniques to a system design with wider view and obtain much more effective power reduction with less cost and effort. In this paper, a transformation technique, called power - conscious loop folding is proposed for high level synthesis of a low power system.Our work is focused on reducing the power consumed by functional units in adata path dominated circuit through the decrease of switching activity. Te transformation algorithm has been implemented and integrated into HYPER, a high level synthesis system for experiments. In our experiments, we could achieve a pwoer reduction of up to 50% for data path dominated circuits.

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Multibody Dynamics of Closed, Open, and Switching Loop Mechanical Systems

  • Youm, Youn-Gil
    • Journal of Mechanical Science and Technology
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    • v.19 no.spc1
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    • pp.237-254
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    • 2005
  • The vast mechanical systems could be classified as closed loop system, open loop system and open & closed (switching) system. In the closed loop system, the kinematics and dynamics of 3-D mechanisms will be reviewed and closed form solutions using the direction cosine matrix method and reflection transformation method will be introduced. In the open loop system, kinematic & dynamic analysis methods regarding the redundant system which has more degrees of freedom in joint space than those of task space are reviewed and discussed. Finally, switching system which changes its phase between closed and open loop motion is investigated with the principle of dynamical balance. Among switching systems, the human gait in biomechanics and humanoid in robotics are presented.

Adaptive Nonlinear Guidance Considering Target Uncertainties and Control Loop Dynamics (목표물의 불확실성과 제어루프 특성을 고려한 비선형 적응 유도기법)

  • 좌동경;최진영;송찬호
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.4
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    • pp.320-328
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    • 2003
  • This paper proposes a new nonlinear adaptive guidance law. Fourth order state equation for integrated guidance and control loop is formulated considering target uncertainties and control loop dynamics. The state equation is further changed into the normal form by nonlinear coordinate transformation. An adaptive nonlinear guidance law is proposed to compensate for the uncertainties In both target acceleration and control loop dynamics. The proposed law adopts the sliding mode control approach with adaptation fer unknown bound of uncertainties. The present approach can effectively solve the existing guidance problem of target maneuver and the limited performance of control loop. We provide the stability analyses and demonstrate the effectiveness of our scheme through simulations.