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101.
A. J. W. Duijvestijn 《BIT Numerical Mathematics》1972,12(3):318-324
The correctness of an in-place permutation algorithm is proved. The algorithm exchanges elements belonging to a permutation cycle. A suitable assertion is constructed from which the correctness can be deduced after completion of the algorithm.An in-place rectangular matrix transposition algorithm is given as an example. 相似文献
102.
Roehrl MH Heffron GJ Wagner G 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2005,174(2):325-330
Spin state selective experiments have become very useful tools in solution NMR spectroscopy, particularly in the context of TROSY line narrowing. However, the practical implementation of such pulse sequences is frequently complicated by unexpected instrument behavior. Furthermore, a literal theoretical analysis of sequences published with specific phase settings can fail to rationalize such experiments and can seemingly contradict experimental findings. In this communication, we develop a practical approach to this ostensible paradox. Spin-dynamic design, rationalization, and simulation of NMR pulse sequences, as well as their confident and reliable implementation across current spectrometer hardware platforms, require precise understanding of the underlying nutation axis conventions. While currently often approached empirically, we demonstrate with a simple but general pulse program how to uncover these correspondences a priori in the general case. From this, we deduce a correspondence table between the spin-dynamic phases used in NMR theory and simulation on the one hand and pulse program phases of current commercial spectrometers on the other. As a practical application of these results, we analyze implementations of the original (1)H-(15)N TROSY experiment and illustrate how steady-state magnetization can be predictably, rather than empirically, added to a desired component. We show why and under which circumstances a literal adoption of phases from published sequences can lead to incorrect results. We suggest that pulse sequences should be consistently given with spin-dynamically correct (physical) phases, rather than in spectrometer-specific (software) syntax. 相似文献
103.
本文介绍了“863”通信技术主题8年来取得的成果,对产业发展的贡献,管理组织的经验和体会,存在的问题,对今后工作的建议。 相似文献
104.
Local branching 总被引:1,自引:0,他引:1
The availability of effective exact or heuristic solution methods for general Mixed-Integer Programs (MIPs) is of paramount importance for practical applications. In the present paper we investigate the use of a generic MIP solver as a black-box ``tactical' tool to explore effectively suitable solution subspaces defined and controlled at a ``strategic' level by a simple external branching framework. The procedure is in the spirit of well-known local search metaheuristics, but the neighborhoods are obtained through the introduction in the MIP model of completely general linear inequalities called local branching cuts. The new solution strategy is exact in nature, though it is designed to improve the heuristic behavior of the MIP solver at hand. It alternates high-level strategic branchings to define the solution neighborhoods, and low-level tactical branchings to explore them. The result is a completely general scheme aimed at favoring early updatings of the incumbent solution, hence producing high-quality solutions at early stages of the computation. The method is analyzed computationally on a large class of very difficult MIP problems by using the state-of-the-art commercial software ILOG-Cplex 7.0 as the black-box tactical MIP solver. For these instances, most of which cannot be solved to proven optimality in a reasonable time, the new method exhibits consistently an improved heuristic performance: in 23 out of 29 cases, the MIP solver produced significantly better incumbent solutions when driven by the local branching paradigm.
Mathematics Subject Classification (2000):90C06, 90C10, 90C11, 90C27, 90C59 相似文献
105.
Stefan M. Stefanov 《Computational Optimization and Applications》2001,18(1):27-48
A minimization problem with convex and separable objective function subject to a separable convex inequality constraint and bounded variables is considered. A necessary and sufficient condition is proved for a feasible solution to be an optimal solution to this problem. Convex minimization problems subject to linear equality/linear inequality constraint, and bounds on the variables are also considered. A necessary and sufficient condition and a sufficient condition, respectively, are proved for a feasible solution to be an optimal solution to these two problems. Algorithms of polynomial complexity for solving the three problems are suggested and their convergence is proved. Some important forms of convex functions and computational results are given in the Appendix. 相似文献
106.
基于CAN总线的井下多参数监控系统的设计 总被引:1,自引:0,他引:1
介绍一种基于CAN总线的矿井下多参数智能参数监控系统.该系统能够实时监测井下包括瓦斯浓度、风速、温度、负压、液位等各种参数,并进行一定处理,再经CAN总线通信传送回井上监控主机,地面主机人机交互通过虚拟仪器来实现,具有工作状况监控、数据记录查询、显示以及历史数据记录和分析等功能,有很高的推广价值. 相似文献
107.
描述了卫星地球站站控与网管系统的作用和现状。以计算机控制技术促进地球站远程监控和网络管理技术等方面发展,详细论述了设计与研发规范化建设的思路,并提出建设模式。自主研发与生产的网管系统将会得到大力发展。 相似文献
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