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261.
给出了数学表达式屏幕输入的C^ 程序,并用类进行了封装.封装之后,成了一个独立模块.以Newton求根迭代程序为例说明,该模块可以方便地嵌入在需要它的其他程序里. 相似文献
262.
In this article, a new molecular alignment procedure to provide general‐purpose, fast, automatic, and user‐intuitive three‐dimensional molecular alignments is presented. This procedure, called Topo‐Geometrical Superposition Approach (TGSA), is only based on comparisons of atom types and interatomic distances; hence, the procedure can handle large molecular sets within affordable computational costs. The method is able to accurately align 3D structures using the common molecular substructures, as inferred by the bonding pattern (atom correspondences), where present. The algorithm has been implemented into a program named TGSA99, and it has been tested over eight different molecular sets: flavilium salts, amino acids, indole derivatives, AZT, steroids, anilide derivatives, poly‐aromatic‐hydrocarbons, and inhibitors of thrombine. The TGSA algorithm performance is evaluated by means of computational time, number of superposed atoms, and index of fit between the compared structures. © 2000 John Wiley & Sons, Inc. J Comput Chem 22: 255–263, 2001 相似文献
263.
基于电信运营商的IPTV新业务定位 总被引:1,自引:0,他引:1
IPTV是电信运营商的一个机遇和挑战。从用户角度出发,应该减少机顶盒的采购成本.降低或转移用户一次性投入,降低用户的进入门槛;从竞争和共赢的角度,应与拥有巨大资源的广电部门合作;要做好积极的宣传引导和网络的升级改造;同时.要积极宣传引导消费者,探寻运营模式和营销策略。 相似文献
264.
根据脉冲探地雷达低成本、高精度和小型化的要求,研制了一种基于微控制器的超宽带(UWB)探地雷达信号控制与数据采集系统。文中分析了延时式等效时间采样原理,阐述了系统总体结构,描述了触发脉冲生成电路和回波数据采集通道的工作原理和设计方法,给出了底层固件的开发流程以及系统软件功能。研制的高集成度嵌入式控制与采集系统,降低了探地雷达系统整体成本,提高了系统的实时性和可靠性。 相似文献
265.
266.
提出了按电气信息类宽口径专业培养人才的思路,并进行了大量的调查研究,提出了改革方案。以西安交通大学电气信息试点班为载体,进行了研究探索与实践,取得了一定的经验和成果。 相似文献
267.
基于dsPIC33F系列单片机的应用程序升级方法 总被引:1,自引:0,他引:1
为了适应客户需求变化或程序BUG的修改,利用dsPIC33F单片机运行时的自编程特性,实现了基于该单片机的应用程序升级功能。在详细描述基本原理的基础上,给出了引导程序的实现流程图,并提供实现流程中一些关键细节的实现方法,最后对实际应用中的升级正确性及继点续传问题进行了探讨。该方法的实现原理同样适用于其他具备运行时自编程或有应用编程功能的单片机中。 相似文献
268.
This paper considers a two-facility supply chain for a single product in which facility 1 orders the product from facility 2 and facility 2 orders the product from a supplier in each period. The orders placed by each facility are delivered in two possible nonnegative integer numbers of periods. The difference between them is one period. Random demands in each period arise only at facility 1. There are physical storage constraints at both facilities in each period. The objective of the supply chain is to find an ordering policy that minimizes the expected cost over a finite horizon and the discounted stationary expected cost over an infinite horizon. We characterize the structure of the minimum expected cost and the optimal ordering policy for both the finite and the discounted stationary infinite horizon problems. 相似文献
269.
This paper addresses a novel competitive facility location problem about a firm that intends to enter an existing decentralized supply chain comprised of three tiers of players with competition: manufacturers, retailers and consumers. It first proposes a variational inequality for the supply chain network equilibrium model with production capacity constraints, and then employs the logarithmic-quadratic proximal prediction–correction method as a solution algorithm. Based on this model, this paper develops a generic mathematical program with equilibrium constraints for the competitive facility location problem, which can simultaneously determine facility locations of the entering firm and the production levels of these facilities so as to optimize an objective. Subsequently, a hybrid genetic algorithm that incorporates with the logarithmic-quadratic proximal prediction–correction method is developed for solving the proposed mathematical program with an equilibrium constraint. Finally, this paper carries out some numerical examples to evaluate proposed models and solution algorithms. 相似文献
270.
Stereospecific assignments of protein NMR resonances based on the tertiary structure and 2D/3D NOE data 总被引:1,自引:0,他引:1
In many cases of protein structure determination by NMR a high-quality structure is required. An important contribution to structural precision is stereospecific assignment of magnetically nonequivalent prochiral methylene and methyl groups, eliminating the need for introducing pseudoatoms and pseudoatom corrections in distance restraint lists. Here, we introduce the stereospecific assignment program that uses the resonance assignment, a preliminary 3D structure and 2D and/or 3D nuclear Overhauser effect spectroscopy peak lists for stereospecific assignment. For each prochiral group the algorithm automatically calculates a score for the two different stereospecific assignment possibilities, taking into account the presence and intensity of the nuclear Overhauser effect (NOE) peaks that are expected from the local environment of each prochiral group (i.e., the close neighbors). The performance of the algorithm has been tested and used on NMR data of alpha-helical and beta-sheet proteins using homology models and/or X-ray structures. The program produced no erroneous stereospecific assignments provided the NOEs were carefully picked and the 3D model was sufficiently accurate. The set of NOE distance restraints produced by nmr2st using the results of the SSA module was superior in generating good-quality ensembles of NMR structures (low deviations from upper limits in conjunction with low root-mean-square-deviation values) in the first round of structure calculations. The program uses a novel approach that employs the entire 3D structure of the protein to obtain stereospecific assignment; it can be used to speed up the NMR structure refinement and to increase the quality of the final NMR ensemble even when no scalar or residual dipolar coupling information is available. 相似文献