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1.
An N-parameter Gaussian stationary process X = { X ( t ): t ∈ RN+ } is introduced and the existence and joint continuity of its local times is presented. And the moments of local times are estimated. Furthermore moduli of continuity and large increment results for the local times are established.  相似文献   

2.
The flow shop scheduling problem with limited buffers ( LBFSP) widely exists in manufacturing systems. A hybrid discrete harmony search algorithm is proposed for the problem to minimize total flow time. The algorithm presents a novel discrete improvisation and a differential evolution scheme with the jobpermutation-based representation. Moreover, the discrete harmony search is hybridized with the problem-dependent local search based on insert neighborhood to balance the global exploration and local exploitation. In addition. an orthogonal experiment design is employed to provide a receipt for turning the adjustable parameters of the algorithm. Comparisons based on the Taillard benchmarks indicate the superiority of the proposed algorithm in terms of effectiveness and efficiency.  相似文献   

3.
An extended nonlinear state predictor (ENSP) for a class of nonlinear systems with input time delay is proposed. Based on the extended Kalman filter (EKF), the ENSP first estimates the current states according to the previous estimations and estimation errors, next calculates the future state values via the system model, and then adjusts the values based on the current errors. After a state predictive algorithm for a class of linear systems is presented, it is extended to a class of nonlinear time delay systems and the detailed ENSP algorithm is further proposed. Finally, computer simulations with the nonlinear example are presented, which demonstrates that the proposed ENSP can effectively and accurately predict the future states for a class of nonlinear time-delay systems no matter whether the state variables change quickly or slowly.  相似文献   

4.
This paper concerns the reliability issues as well as queueing analysis of M/G/1 retrial queues with general retrial times and server subject to breakdowns and repairs. We assume that the server is unreliable and customers who find the server busy or down are queued in the retrial orbit in accordance with a first-come-first-served discipline. Only the customer at the head of the orbit queue is allowed for access to the server. The necessary and sufficient condition for the system to be stable is given. Using a supplementary variable method, we obtain the Laplace-Stieltjes transform of the reliability function of the server and a steady state solution for both queueing and reliability measures of interest. Some main reliability indexes, such as the availability, failure frequency, and the reliability function of the server, are obtained.  相似文献   

5.
To obtain more accurate correlation dimension estimations for chaotic time series, a novel scaling region identification method is developed. First, points that obviously do not belong to the scaling region associated with the whole double logarithm correlation integral curve are removed using the K-means algorithm. Second, a point-slope-error algorithm is developed to recognize a possible scaling region. Third, the K-means algorithm is used again to further remove a small interval of interfering points in the possible scaling region to obtain a more precise scaling region. The correlation dimension of four typical chaotic attractors and five curves generated by the Weierstrass-Mandelbrot fractal function were calculated using the proposed method. These calculated values were very close to the respective theoretical fractal dimensions. Moreover, the effectiveness of our method in identifying the scaling region was compared with existing methods. Results show that our method can distinguish the scaling region objectively, accurately, automatically and quickly, making estimations of the correlation dimension more precise and affording significant improvements in nonlinear analysis.  相似文献   

6.
This paper concerns the reliability issues as well as queueing analysis of M/G/1 retrial queues with general retrial times and server subject to breakdowns and repairs. We assume that the server is unreliable and customers who find the server busy or down are queued in the retrial orbit in accordance with a first-come-first-served discipline. Only the customer at the head of the orbit queue is allowed for access to the server. The necessary and sufficient condition for the system to be stable is given. Using a supplementary variable method, we obtain the Laplace-Stieltjes transform of the reliability function of the server and a steady state solution for both queueing and reliability measures of interest. Some main reliability indexes, such as the availability, failure frequency, and the reliability function of the server, are obtained.  相似文献   

7.
This paper concerns the reliability issues as well as queueing analysis of M/G/1 retrial queues with general retrial times and server subject to breakdowns and repairs. We assume that the server is unreliable and customers who find the server busy or down are queued in the retrial orbit in accordance with a first-come-first-served discipline. Only the customer at the head of the orbit queue is allowed for access to the server. The necessary and sufficient condition for the system to be stable is given. Using a supplementary variable method, we obtain the Laplace-Stieltjes transform of the reliability function of the server and a steady state solution for both queueing and reliability measures of interest. Some main reliability indexes, such as the availability, failure frequency, and the reliability function of the server, are obtained.  相似文献   

8.
The Clapping and Broadcasting Synchronization (CBS) algorithm,which is specifically designed for large-scale sensor networks with low communication overhead and high synchronization accuracy,is introduced.The CBS protocol uses broadcasting rather than pairwise communication to accomplish synchronization.In the CBS scheme,the initial offset of local clocks can be successfully eliminated by the operation of clapping nodes,which leads to significant improvement in synchronization accuracy.The CBS protocol was implemented on the TelosB platform and its performance was evaluated in a variety of experiments.The results demonstrate that the CBS protocol outperforms the current state-of-the-art approach,the Flooding Time Synchronization Protocol (FTSP),in both single-hop and multi-hop scenarios in terms of synchronous precision and energy consumption.In multi-hop scenarios,the CBS algorithm keeps about 50% of its synchronization errors within 1 ms.In comparison,the FTSP keeps less than 7% of its synchronization errors within this range.In both single-hop and multi-hop scenarios,the CBS protocol is over 3.2 times more energy-efficient than the FTSP.  相似文献   

9.
Correlations for the ignition delay times of hydrogen/air mixtures were developed using the method of High Dimensional Model Representation (HDMR).The hydrogen/air ignition delay times for initial conditions over a wide range of temperatures from 800 to 1600 K,pressures from 0.1 to 100 atm,and equivalence ratios from 0.2 to 10 were first calculated utilizing the full chemical mechanism.Correlations were then developed based on these ignition delay times.Two forms of correlations were constructed:the first one is an overall general model covering the whole range of the initial conditions;while the second one is a piecewise correlation model valid for initial conditions within different sub-domains.The performance of these correlations was studied through comparison with results from the full chemical mechanism as well as experimental data.It was shown that these correlations work well over the whole range of initial conditions and that the accuracy can be significantly improved by using different piecewise correlations for different sub-domains.Therefore,piecewise correlations can be used as an effective replacement for the full mechanism when the prediction of chemical time scale is needed in certain combustion modeling.  相似文献   

10.
To overcome disadvantages of traditional worst-case execution time (WCET) analysis approaches, we propose a new WCET analysis approach based on independent paths for ARM programs. Based on the results of program flow analysis, it reduces and partitions the control flow graph of the program and obtains a directed graph. Using linear combinations of independent paths of the directed graph, a set of feasible paths can be generated that gives complete coverage in terms of the program paths considered. Their timing measurements and execution counts of program segments are derived from a limited number of measurements of an instrumented version of the program. After the timing measurement of the feasible paths are linearly expressed by the execution times of program seg-ments, a system of equations is derived as a constraint problem, from which we can obtain the execution times of program segments. By assigning the execution times of program segments to weights of edges in the directed graph, the WCET estimate can be calculated on the basis of graph-theoretical techniques. Comparing our WCET estimate with the WCET measurement obtained by the exhaustive measurement, the maximum error ratio is only 8.259 3 %. It is shown that the proposed approach is an effective way to obtain the safe and tight WCET estimate for ARM programs.  相似文献   

11.
离散加工时间可控的排序问题,得到界为3/2的多项式时间近似算法。  相似文献   

12.
凸二次规划松驰方法研究离散加工时间可控排序问题   总被引:1,自引:1,他引:1  
用凸二次规划松弛方法研究离散加工时间可控的排序问题,得到界为3/2的多项式时间近似算法。  相似文献   

13.
用凸二次规划松弛方法研究工件具有就绪时间,目标函数为工件总拒绝费用与接受工件的带权总完工时间之和的工件可拒绝排序问题,得到界为2的多项式时间近似算法.  相似文献   

14.
研究单台机器有使用限制的排序问题,即机器在给定的一个时间段内不可用,目标为最小化最大完工时间.每个工件都有一个到达时间,只有工件到达了才能加工,工件在加工过程中不可中断.对于该问题的离线情形,给出了一个近似比为4/3的近似算法和一个动态规划算法.对于问题的在线情形,给出了一个最优在线算法.  相似文献   

15.
考虑多纤波分复用链网与环网中的利润极大化问题, 分别给出了多项式时间精确算法和2 近似算法. 对于环上各边光纤数目相同的均匀模式, 给出了1.582 近似算法. 这些结果也适用于有向链网与环网.  相似文献   

16.
分子生物学中基因元方向的反转基因组重排问题在数学上已被证明是一个NP-难问题。目前,较好的算法是Christie(2001)的3/2-近似算法,本文给出一种适合于计算基因元方向的反转基因组重排问题的模拟退火算法,定义了解的邻域结构,数据实验的结果表明该算法性能优于3/2-近似算法。  相似文献   

17.
工件具有安装时间的排序问题最近几年受到越来越多的关注,主要讨论了一类有安装时间且与加工位置有关的单机排序模型。在该模型中,所有工件在机器上加工时,一次只能加工一个工件,工件的相邻加工工序之间不允许出现空闲,工件的实际加工时间不是一成不变的,它不仅与工件的基本加工时间有关,同时还与工件所处的加工位置有关,工件的安装时间是依赖于已加工工件的实际加工时间的简单函数,即p-s-d形式。对目标函数为极小化最大完工时间,极小化完工时间和以及极小化总完工时间差等问题进行讨论,分别给出了多项式算法和算法复杂性。还证明了对于目标函数为完工时间,提前完工时间以及误工时间的加权和最小化问题是多项式可解的。  相似文献   

18.
为了解决在实时调度系统中,任务执行时间不确定性所带来的问题,提出了基于时间预测的调度方案。该方案设计了VSM(vectorspacemodel)模型、Markov模型和MVSM(Markovvectorspacemodel)模型。对这3种模型的比较表明:基于MVSM模型的调度方案可以很好地保证实时系统的效率和稳定性,即使在处理器超载的情况下,也能自动调节,超过99%的作业可以在时间期限之前完成。采用时间预测的方法,可以较好地解决任务执行时间不确定性所带来的影响,为不确定环境下的实时调度系统提供一种很好的参考解决方案。  相似文献   

19.
讨论了互联网信息组织和规划的一个新问题:带拒绝装箱问题,利用原始对偶互补松弛条件给出此问题的一个最优值的下界,利用下界值对应解的性质得到带拒绝装箱问题的一个近似算法.  相似文献   

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