家庭文化资本对学生学业成绩的影响及对策研究——基于石河子市某初中的调研

家庭文化资本不但是家庭社会地位的象征,还是影响家中子女学业成就获得的关键因素。为了深入了解家庭文化资本对学生学业成绩的影响状况,本研究选取石河子市某初中学校,按照分层抽样的方法选取229名学生作为被试,采用自编的《家庭文化资本问卷》,探求初中生家庭文化资本与其学业成绩的关系。结果显示,石河子市初中生家庭文化资本对学生学业成绩的有极其显著的正向影响,家庭文化氛围、父母和学生本人对学生将来学历的期望对学生学业成绩有显著的正向影响。     

中学学习型教师团队建设探索——以华山中学为例

学习型组织具有五个要素,即自我超越、改善心智模式、建立共同愿景、团队学习、系统思考,学习型教师团队同样要符合这些特征。为此,华山中学开展了积极探索,提出创建学习型教师团队的关键是:建立共同愿景,提升生命力;改变学习方式,增强学习力;变革管理模式,培养创造力。初步营造出了凝心聚力实现又好又快发展的良好教育氛围,促进了学校教育实践的全面开展。     

水下航行体惯性类水动力系数的计算方法

为了系统地计算水下航行体全套惯性类水动力系数,提高计算效率和计算精度,通过基于无粘模型的计算方法对水下航行体的运动进行了预报;通过UDF及动网格技术,对匀速运动和匀加速运动的SUBOFF模型进行了分析.设计了单方向速度线性变化的匀加速直线运动和匀加速回转运动,并通过换算和数值拟合处理得到了潜艇所受的惯性力和惯性类水动力系数.该系数与试验误差保证在6％之内,验证了所提方法的可行性及准确性.     

Choosing arrival process models for service systems: Tests of a nonhomogeneous Poisson process

Service systems such as call centers and hospital emergency rooms typically have strongly time‐varying arrival rates. Thus, a nonhomogeneous Poisson process (NHPP) is a natural model for the arrival process in a queueing model for performance analysis. Nevertheless, it is important to perform statistical tests with service system data to confirm that an NHPP is actually appropriate, as emphasized by Brown et al. [8]. They suggested a specific statistical test based on the Kolmogorov–Smirnov (KS) statistic after exploiting the conditional‐uniform (CU) property to transform the NHPP into a sequence of i.i.d. random variables uniformly distributed on [0,1] and then performing a logarithmic transformation of the data. We investigate why it is important to perform the final data transformation and consider what form it should take. We conduct extensive simulation experiments to study the power of these alternative statistical tests. We conclude that the general approach of Brown et al. [8] is excellent, but that an alternative data transformation proposed by Lewis [22], drawing upon Durbin [10], produces a test of an NHPP test with consistently greater power. We also conclude that the KS test after the CU transformation, without any additional data transformation, tends to be best to test against alternative hypotheses that primarily differ from an NHPP only through stochastic and time dependence. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 66–90, 2014     

Some comparisons of residual life of coherent systems with exchangeable components

Most of the research, on the study of the reliability properties of technical systems, assume that the components of the system operate independently. However, in real life situation, it is more reasonable to assume that there is dependency among the components of the system. In this article, we give sufficient conditions based on the signature and the joint distribution of component lifetimes to obtain stochastic ordering results for coherent and mixed systems with exchangeable components. Some stochastic orders on dynamic (or conditional) signature of coherent systems are also provided. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 549–556, 2014     

基于正交锁定差分放大器的巨磁阻抗（GMI）磁传感器

基于非晶丝的巨磁阻抗(GMI)效应,利用CoFeBSi非晶丝作为敏感材料,采用正交锁定放大电路和仪用放大器作为信号调理电路,设计了一种差分式高灵敏度GMI磁传感器。介绍了巨磁阻抗效应的基本概念和双非晶丝差分结构的磁敏探头,分析了基于正交锁定差分放大技术的信号调理电路的工作原理,并结合非晶丝两端输出信号的幅度和相位特性,提出了正交锁定放大器输出包络的近似计算方法。实验结果表明:在-2.0 Oe~+2.0 Oe的量程内,该GMI磁传感器灵敏度可达748mV/Oe,线性误差为0.98%FS,且噪声平均功率谱密度约为0.8nT/Hz1/2。     

Counterinsurgency American style: Considering David Petraeus and twenty-first century irregular war

This article examines the complex legacy of David Petraeus who was a key figure in the emergence of the US military shift towards counterinsurgency doctrine in the years after 2006. Although Petraeus has been perceived by critics as a publicity seeker, he can be credited with laying the foundations for a more serious commitment to COIN involving in particular in integrating conventional and Special Forces in arenas like village stability operations. The article looks a Petraeus's role in both Iraq and Afghanistan: it concludes that, in the case of Afghanistan, it is too early to assess whether counterinsurgency has had a decisive impact of the outcome of the war against the Taliban.     

考虑可观测度的反交会规避机动方法

针对具有自主接近能力的航天器开展了反交会规避机动方法研究。建立了仅测角相对导航模型,随后利用状态估计误差给出了可观测度的定义,量化了可观测性指标。以可观测度为评价指标,提出基于虚拟轨道的可观测度计算方法,以可观测度梯度对规避机动方向进行优化,保证了规避机动使目标航天器的可观测性达到最大弱化,并给出了规避机动大小计算方法。给出了仿真算例,结果表明提出的方法能够使系统的可观测性明显减弱,达到了设计要求,为规避机动研究提供了一种新视角。     

卫星导航系统的体系安全性分析方法

为了应对卫星导航系统内部复杂关系等体系特征为其安全分析带来的挑战、全面识别和分析卫星导航系统面临的体系安全威胁、提高系统的安全性和服务能力,基于功能依赖网络分析理论提出了从体系角度研究卫星导航系统安全性的建模方法,重点对导航系统内组件系统之间交互关系导致的危险传播、任意失效组合进行了后果分析和原因调查。仿真结果表明该方法能清晰地描述危险传播和失效组合的过程以及进行正逆向的推理分析,也证明了该方法在卫星导航系统安全分析问题上的潜力和适用性。