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91.
以旅行者的旅行时间最短为优化目标,用竞争分析的方法考虑了自然灾害环境中的在线导航问题,提出了旅行者在受灾区行走的上界控制策略,通过竞争比和竞争性能分析,结果表明上界控制策略具有该问题最优竞争比2k+1,并且竞争性能得到了提高. 相似文献
92.
陈世军 《宁德师专学报(自然科学版)》2010,22(4):340-344
建立了求矩阵方程组的双对称解的迭代算法.使用该方法不仅可以判断矩阵方程组是否有双对称解,而且在有双对称解时,还能够在有限步迭代计算之后得到矩阵方程组的双对称极小范数解.同时,也能够在矩阵方程组的对称解集合中求得给定矩阵的最佳逼近. 相似文献
93.
To solve the Fredholm integral equations of the second kind, a new notion of the least-squares orthogonal polyno- mials of function-valued Pade-type approximation is introduced. On the basis of the error formula, the least-squares function: valued Pad&type approximation is constructed. Their existence and uniqueness are studied. A recursive computation formula of the least-squares function-valued Padetype approximation is given. In the end, an example is given to show that the method is effective and stable. 相似文献
94.
首先利用微分不等式研究如下类型的周期边值问题{y''=f(t,y,y'),0〈t〈l y(0)=y(t),y'(0)=y'(l).的微分不等式与解的存在性,并在一定条件下把解延拓成为微分方程在无穷时间区N-Y-N期解,然后利用所得结果讨论奇异摄动现象. 相似文献
95.
2004年孙春玲等研究了一维装箱问题,给出了一个近似程度最好的近似值为3/2的近似算法-交叉算法.遗憾的是他们的交叉算法的近似值分析是错误的,本文通过两个反例说明了他们的错误所在,并给出一个正确的近似值分析. 相似文献
96.
应用上下解和迭代方法研究了一类含多个离散时滞的单种群模型,得到了该方程周期解的存在唯一的一个充分条件。 相似文献
97.
98.
Jo Ann Kollath Margaret J. Safrit Weimo Zhu Long-Guang Gao 《Research quarterly for exercise and sport》2013,84(4):432-435
In a review of 46 meta-analyses of gender differences, overhand throwing had the largest gender difference favoring boys (ES > 3.0). Expectations for gender-specific performances may be less pronounced in female Australian Aborigines, because historical accounts state they threw for defense and hunting. Overhand throwing velocities and kinematics were recorded in 30 female and male Aboriginal Australian children 6-10 years old. Results indicated the Aboriginal girls and boys were more similar in horizontal ball velocities than U.S. girls and boys. Throwing kinematics between girls and boys were also more similar in Australian Aborigines than U.S. children. Aboriginal girls threw with greater velocities than U.S., German, Japanese, and Thai girls, while the boys were similar across cultures. 相似文献
99.
Michael J. Falvo Brian K. Schilling Lawrence W. Weiss 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):293-311
Power is an integral aspect of many sports. Although power output of the lower body is often measured during jumping and cycling movements, much less is known about power as pertains to the upper body musculature. Recently, isoinertial methods ‐ with constant gravitational load ‐ of power testing have become common, but little is known of the reliability and criterion validity of these tests as they pertain to sport performance. In addition, the varied methodology makes a lucid model more evasive. The aims of this review are to examine the various methods of assessing upper body power, to establish its role in predicting athletic performance, and to assess the body of literature that has assessed power output of the upper extremities by isoinertial methods. To our knowledge, only two studies on isoinertial upper‐body power have shown a direct correlation to sporting ability (Baker, 2001; Baker et al., 2001); therefore, many unanswered questions exist as to the efficacy of these tests as predictors of athletic ability or as a method to track athletes’ training over time. From this review we hope to allow the sport coach to assess the overall utility of these tests in terms of availability, safety and external validity. 相似文献
100.
关于简单线性恶化问题的平行机排序的一个全多项式逼近算法 总被引:1,自引:0,他引:1
In this paper, a parallel machine scheduling problem was considered , where the processing time of a job is a simple linear function of its starting time. The objective is to minimize makespan. A fully polynomial time approximation scheme for the problem of scheduling n deteriorating jobs on two identical machines was worked out. Furthermore, the result was generalized to the case of a fixed number of machines. 相似文献