新课程理念下数学探究教学的理论与实践探索

数学探究教学作为新课程标准倡导的一种教学模式,它注重学生的参与体验,强调在教师的指导和点拨下展开具有探究性和一定创造性的教学活动。探究教学是发展学生个体,培养学生能力,提高学生素质的重要途径。另外,有关探究教学案例的开发也是不容忽视的一个重要方面。     

双37毫米舰炮射击终止时弹壳贴膛故障的分析及改进措施

分析了双３７舰炮射击终止时产生弹壳贴膛,退壳困难的故障,详细探讨故障产生原因,提出在装备使用过程中,使机械和电气的动作能相互制约,相互控制,避免射击终止时弹壳贴膛的改进措施。     

The stochastic single resource service‐provision problem

The service‐provision problem described in this paper comes from an application of distributed processing in telecommunications networks. The objective is to maximize a service provider's profit from offering computational‐based services to customers. The service provider has limited capacity and must choose which of a set of software applications he would like to offer. This can be done dynamically, taking into consideration that demand for the different services is uncertain. The problem is examined in the framework of stochastic integer programming. Approximations and complexity are examined for the case when demand is described by a discrete probability distribution. For the deterministic counterpart, a fully polynomial approximation scheme is known 2 . We show that introduction of stochasticity makes the problem strongly NP‐hard, implying that the existence of such a scheme for the stochastic problem is highly unlikely. For the general case a heuristic with a worst‐case performance ratio that increases in the number of scenarios is presented. Restricting the class of problem instances in a way that many reasonable practical problem instances satisfy allows for the derivation of a heuristic with a constant worst‐case performance ratio. Worst‐case performance analysis of approximation algorithms is classical in the field of combinatorial optimization, but in stochastic programming the authors are not aware of any previous results in this direction. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003     

含收益带费用的校对问题的最优停止

在假定每次校对费用可能不一样且带来一定收益的条件下,讨论了校对问题的最优停止,给出了Ｐｏｉｓｓｏｎ模型与二项模型的最优停时。     

任职教育中案例教学方法探析——以《中国近现代史纲要》课程为例

案例教学法被逐步地引进任职教育的课堂,本文以《中国近现代史纲要》课程为例,探析了任职教育中案例教学法的应用。从教学目的、教学内容和教学对象三个方面分析了《中国近现代史纲要》课程运用案例教学的可行性。从《中国近现代史纲要》课程运用案例教学的意义可以看出,案例教学是作为该课程教学改革的最佳途径。运用案例教学时,在案例选取上兼顾真实性、针对性、时效性,在案例分析过程中注重教学主体和客体的双向交流,在案例总结时注重案例结论与讨论论点的区别。     

A heuristic for maximizing the number of on‐time jobs on two uniform parallel machines

We consider the problem of maximizing the number of on‐time jobs on two uniform parallel machines. We show that a straightforward extension of an algorithm developed for the simpler two identical parallel machines problem yields a heuristic with a worst‐case ratio bound of at least . We then show that the infusion of a “look ahead” feature into the aforementioned algorithm results in a heuristic with the tight worst‐case ratio bound of , which, to our knowledge, is the tightest worst‐case ratio bound available for the problem. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

基于组合设计的软件可靠性测试方法

提出了将实验设计中的组合设计方法应用于软件可靠性测试。分析了组合设计方法在软件可靠性测试用例设计中应用的理论基础和基于组合设计的软件可靠性测试的一般方法。同时指出了利用软件操作剖面信息和失效数据进行可靠性评估的方法。     

火灾微量物证的发现与提取方法研究

针对基层火灾调查人员在发现与提取火灾微量物证中存在的实际问题,从火灾微量物证的概念、特点和种类出发,归纳总结了火灾现场不同火灾微量物证的发现、提取与包装方法,给出了发现与提取火灾微量物证的基本要求和应注意的问题。     

目标起伏特性对雷达威力性能的影响分析

介绍了典型雷达目标RCS起伏模型,阐述了起伏目标在实际中的应用,建立了目标损耗和雷达作用距离之间的关系,为不同目标的等效替代推算提供了理论依据.验证了雷达目标满足卡平方分布时发现概率和起伏因子之间的关系.并针对不同类型的起伏目标,建立了雷达探测距离和发现概率之间的关系,为雷达的威力检测和飞行目标的航线设计提供依据.     

符号执行火控系统诸元解算程序测试用例生成技术

火控系统作为各种武器装备的中枢和大脑,控制着武器系统的运转,其有效性直接关系着射击的成败甚至武器系统的综合效能。诸元解算程序是将各种输入条件依据弹道模型经过多次迭代转换为射击诸元,由于其复杂性,当前软件测试用例只是在几个关键点上进行校验,很难覆盖程序所有分支和路径,存在着测试不充分。针对这个问题,提出了一种基于符号执行的用例自动生成技术,结合解弹道方程组约束条件和程序分支控制变量使用符号执行框架内能够得到覆盖所有可能的执行路径,从而保证测试的充分性。