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81.
82.
Youngchul Cho Nacer-Eddine Zergainoh Sungjoo Yoo Ahmed Amine Jerraya Kiyoung Choi 《Design Automation for Embedded Systems》2007,11(2-3):167-191
In multiprocessor system-on-chip, tasks and communications should be scheduled carefully since their execution order affects
the performance of the entire system. When we implement an MPSoC according to the scheduling result, we may find that the
scheduling result is not correct or timing constraints are not met unless it takes into account the delays of MPSoC architecture.
The unexpected scheduling results are mainly caused from inaccurate communication delays and or runtime scheduler’s overhead.
Due to the big complexity of scheduling problem, most previous work neglects the inter-processor communication, or just assumes
a fixed delay proportional to the communication volume, without taking into consideration subtle effects like the communication
congestion and synchronization delay, which may change dynamically throughout tasks execution. In this paper, we propose an
accurate scheduling model of hardware/software communication architecture to improve timing accuracy by taking into account
the effects of dynamic software synchronization and detailed hardware resource constraints such as communication congestion
and buffer sharing. We also propose a method for runtime scheduler implementation and consider its performance overhead in
scheduling. In particular, we introduce efficient hardware and software scheduler architectures. Furthermore, we address the
issue of centralized implementation versus distributed implementation of the schedulers. We investigate the pros and cons
of the two different scheduler implementations. Through experiments with significant demonstration examples, we show the effectiveness
of the proposed approach. 相似文献
83.
Shu-min Li 《Reports on Mathematical Physics》2007,60(1):107-116
By analyzing the virtual work of reaction forces, we prove the failure of the vakonomic model in obtaining the correct equations of motion for nonholonomic mechanical systems. Only when the constraint is integrable can the actual equation of motion be obtained. We show that the null virtual work condition of reaction forces is a robust criterion on the validity of various models of analytical mechanics. For an illustration, classical examples are discussed. 相似文献
84.
为提高移动机器人的位置估计精度和跟踪效果,提出一种基于道路约束条件下的移动机器人鲁棒约束H∞滤波(CHF)跟踪算法.首先,将机器人移动的道路网络作为跟踪的约束条件,并利用当前统计模型对机器人的运动进行建模.其次,将道路约束条件作为机器人跟踪的非线性状态约束,利用最小协方差估计推导了鲁棒CHF递推方程.通过拉格朗日乘子法对非线性约束优化估计问题进行求解,并利用约束信息对CHF算法的状态更新过程进行了改进.最后,通过对CHF算法和无约束的H∞滤波算法的跟踪性能进行了对比分析和验证.仿真结果表明,该算法可以实现机器人的跟踪,且跟踪精度优于HF算法. 相似文献
85.
A new method is introduced for solving equality constrained nonlinear optimization problems. This method does not use a penalty
function, nor a filter, and yet can be proved to be globally convergent to first-order stationary points. It uses different
trust-regions to cope with the nonlinearities of the objective function and the constraints, and allows inexact SQP steps
that do not lie exactly in the nullspace of the local Jacobian. Preliminary numerical experiments on CUTEr problems indicate that the method performs well.
相似文献
86.
Firdaus E. Udwadia 《Applied mathematics and computation》2010,217(3):1253-1265
This paper deals with an explanation of a paradox posed by Hamel in his 1949 book on Theoretical Mechanics. The explanation deals with the foundations of mechanics and points to new insights into analytical dynamics. 相似文献
87.
Wies?awa T. Obuchowska 《European Journal of Operational Research》2012,218(1):58-67
In this paper we address the problem of the infeasibility of systems defined by reverse convex inequality constraints, where some or all of the variables are integer. In particular, we provide a polynomial algorithm that identifies a set of all constraints critical to feasibility (CF), that is constraints that may affect a feasibility status of the system after some perturbation of the right-hand sides. Furthermore, we will investigate properties of the irreducible infeasible sets and infeasibility sets, showing in particular that every irreducible infeasible set as well as infeasibility sets in the considered system, are subsets of the set CF of constraints critical to feasibility. 相似文献
88.
A technique for maintaining the positive definiteness of the matrices in the quasi-Newton version of the SQP algorithm is proposed. In our algorithm, matrices approximating the Hessian of the augmented Lagrangian are updated. The positive definiteness of these matrices in the space tangent to the constraint manifold is ensured by a so-called piecewise line-search technique, while their positive definiteness in a complementary subspace is obtained by setting the augmentation parameter. In our experiment, the combination of these two ideas leads to a new algorithm that turns out to be more robust and often improves the results obtained with other approaches. 相似文献
89.
For stochastic control problems with mixed state-control constraints, we develop a dynamics aggregation method which replaces the stochastic differential or difference equation with a simpler constraint. Solutions of such simplified problems are used to construct a sequence of approximations to the original problem. Convergence properties of the method for both discrete-time and continuous-time models are analyzed in detail. 相似文献
90.
Tong Xiaojiao Zhou Shuzi Dept. of Appl.Math. Hunan Univ. Changsha . Dept.of Math. Changsha Univ.of Electric Power Changsha 《高校应用数学学报(英文版)》2000,(2)
§ 1 IntroductionIn this paper we study the following nonlinear equality constrained optimization prob-lem:minimize f(x) ,subjectto h(x) =0 ,(P)where h(x) =(h1 (x) ,h2 (x) ,...,hm(x) ) T,f and hi(i=1 ,2 ,...,m) are Rn→R twice conti-nously differentiable(m≤n) .Many authors have studied the problem(P) with trustregion method(see,references[1~ 3 ] ) .These methods have the same property:to enforce strict monotonicity for meritfunction at every iteration.Paper[4 ] shows thatstrictmonotonic … 相似文献