关键词： 算法   信息技术课程   数学课程  

摘要： 算法作为计算机科学的灵魂和数学的重要组成部分,其作用日益增强,已经成为一种强有力的通用智慧工具。高中数学面临的挑战是如何充分利用算法资源,使学生不仅更具知识,而且更加智慧。因此,在新出台的《普通高中数学课程标准(实验)》中明确将算法相关知识纳入到必修模块"算法初步"中,而信息技术课程则将其归入选修模块"算法与程序设计"中。从社会、新课改、学科和师生等角度可以认为"算法"是高中信息技术课程和数学课程间的桥梁。

关键词： mechanistic model   hybrid genetic algorithm   first flush   pollutograph   storm-water   highway runoff  

摘要： A mechanistic model was developed to predict the highway runoff pollutographs during precipitation events. Pollutants were asmmed to be in two phases, attached to the pavement surface and mobile in the runoff water. Detachment and reattachment of contaminants were considered as rate-limited processes and. the detachment rate was assumed to be a function of flow velocity by a power expression. The build-up of pollutants on the surface during the dry period between the storm events was also included in the model. Using measured pollutographs from three highly urbanized highway sites in Los Angeles, California, a hybrid genetic algorithm was used to estimate the model parameters for four different constituents including total suspended solids, oil and grease, dissolved copper, and particulate copper. The model was then validated by predicting pollutographs for the same site for a different monitoring season. Results revealed that estimated model parameters were different for particle -associated and dissolved constituents. These findings suggest different mechanisms governing the detachment of particle-associated and dissolved constituents from the surface. The results have also indicated that there is a linear build-up of pollutants during the dry period and the removal of pollutants during dry periods was insignificant. From these findings, it has been concluded that either the removal rate during the dry period is small or it is not proportional to the concentration of pollutants accumulated on the surface. In general, the build-up contaminant concentrations from the build-up model followed the same trend. However, in some cases the estimated and measured pollutograph did not closely match that may be due to some unknown factors affecting the build-up rates in the current model. (C) 2008 Elsevier B.V. All rights reserved.

关键词： 矿井火灾   改进Dijkstra算法   救灾路线   数学模型   MapObject   应急救援  

摘要： 运用运筹学中图论的理论和方法建立了井下火灾动态救灾路线数学模型,用改进的Dijkstra算法求解该模型并用MapObject控件实现.结合井下火灾时期救灾路线动态选择过程详细介绍了改进的Dijkstra算法运算的各个步骤,拟合出矿井火灾时期人员停留和行走时间与温度的关系函数.以东庞矿矿井灾害应急救援项目为例,通过程序运算,在东庞矿井下巷道分布示意图上动态搜索救灾人员营救受灾人员的最佳救灾路线,不但实现了可视化要求而且效率高,为矿井火灾救灾提供了有力的技术支持.

关键词： 高考数学   试题设计   数列求和   选择题   程序框图   等比数列  

摘要： 2009年福建省将进行"课标课程"的第一次高考.本刊特邀部分专家从不同的视角对全国高考"课标课程"数学理科试卷进行评析,以期为2009年福建省"课标课程"高考的复习迎考提供借鉴.

关键词： 二值化   形态学细化   线性跟踪   线性选择  

摘要： 在航空图像中提取道路信息具有十分重要的军事和民用价值。利用航空图像中道路与背景之间通常存在着灰度差异,结合数学形态学知识,提出了一种基于数学形态学细化的线性跟踪选择算法,并对算法进行了详细描述和算法优点分析,通过实验验证了算法的有效性,实验证明所设计的线性跟踪选择算法检测效率较高,参数易于选择,道路提取效果好,具有较高的应用价值。

关键词： 电力系统   电热协调   电热耦合   潮流模型   热平衡方程  

摘要： 电热协调(ETC)理论的提出对实时环境下输电元件载荷能力的有效利用具有重要意义,但由于电与热之间的紧密耦合,使电力系统的潮流计算变得复杂,文中针对该问题进行了深入研究。将输电线路热动态微分方程引入到现有的电力系统潮流模型之中,利用隐式梯形的差分方法将该微分方程代数化,使输电线路温度成为电力系统运行的一个新的状态量,从而提出了计及电热耦合的潮流计算数学模型,并在推导得到牛顿法求解该模型的修正方程基础上,进一步提出了适应电热耦合处理的简化计算方法,该模型和算法实现了电气量和其温度的统一处理,不仅反映潮流的电的信息,而且能够提供输电线路热惯性的动态过程,即温度变化信息,从而实现输电线路载荷能力由温度评判的目的。最后通过算例分析验证了该模型和算法的有效性,为进一步开展电力系统运行调度中的电热协调理论研究奠定了基础。

关键词： 奇异值分解   数字水印   几何攻击  

摘要： 本文提出了一种利用奇异值分解的图像数字水印算法，针对的是在水印提取之前遭受了未知几何攻击的图像。实验结果表明，本文的算法对放大、旋转等几何攻击以及对剪切，噪声攻击是稳健的，而且此水印在受到了上述的几何攻击后仍能够被有效的提取。

关键词： semirings   local computation   join tree decompositions   soft constraints   uncertainty   valuation networks   valuation algebras  

摘要： Local computation in join trees or acyclic hypertrees has been shown to be linked to a particular algebraic structure, called valuation algebra. There are many models of this algebraic structure ranging from probability theory to numerical analysis, relational databases and various classical and non-classical logics. It turns out that many interesting models of valuation algebras may be derived from semiring valued mappings. In this paper we study how valuation algebras are induced by semirings and how the structure of the valuation algebra is related to the algebraic structure of the semiring. In particular, c-semirings with idempotent multiplication induce idempotent valuation algebras and therefore permit particularly efficient architectures for local computation. Also important are semirings whose multiplicative semigroup is embedded in a union of groups. They induce valuation algebras with a partially defined division. For these valuation algebras, the well-known architectures for Bayesian networks apply. We also extend the general computational framework to allow derivation of bounds and approximations, for when exact computation is not feasible. (C) 2008 Elsevier B.V. All rights reserved.

关键词： 02.60.Lj   81.65.Kn  

摘要： A mathematical model and a numerical method for computing the electric fields of the pipeline cathodic protection with extended anodes in a three-dimensional semirestricted domain. The developed algorithm and program allow one to assess the effect of geometrical parameters on the effectiveness of the cathodic protection of main pipelines.

关键词： 超级计算机   西班牙   数学家   算法   专家   研究人员   加泰罗尼亚   全世界  

摘要： 西班牙加泰罗尼亚理工大学的研究人员日前借助一台超级计算机发现了一种可以破解困扰全世界数学家近1个世纪的”费克特（Fekete）问题”的算法。这台名为“世界尽头”的超级计算机被认为是目前世界上功能最强的计算机，它为研究人员破解“费克特问题”打下了基础。