车辆对不平整路面的随机动压力分析

采用双自由度四分之一车辆模型,以路面不平整和车辆发动机振动为激励,运用随机过程理论分析了车辆对不平整路面的随机动压力,得到了车辆动压系数的概率分布以及最大动压系数与路面不平整度、车速、悬挂质量以及悬挂系统与非悬挂系统特性之间的关系。算例分析表明,引起车辆振动的路面不平整波形的频率范围主要集中在0.04～2.0之间,最大动压系数随路面不平整度、车速、悬挂与非悬挂系统刚度的增大而增大,随着悬挂质量以及悬挂系统阻尼的增大而减少,而轮胎阻尼对车辆动荷载的影响并不显著。     

我国网络学院网站响应时间测试结果及分析

本研究模拟远程学习者基于网络进行自主学习的情境,应用网站能力测试软件Web-CT 4．0,对我国网络学院网站的响应时间作了测试,同时利用SPSS软件处理测试数据。研究发现,2005年度我国网络学院网站性能有明显改善,性能优越的网站比例从2005年初的1／3上升到2006年初的2／3,学习者对网站服务的平均满意度从2005年初的基本满意上升为满意;但网站之间的性能差异较大,目前仍有15％的网站性能差或很差。从地区分布情况来看,上海、北京、湖北等地区总体水平较高,东北、陕西等地区总体水平较低。作者建议, 尽快出台相关学习支持服务标准,提高学习支持服务的效率。     

Relationship of proprioception,cutaneous sensitivity,and muscle strength with the balance control among older adults

BackgroundBalance impairment is one of the strongest risk factors for falls. Proprioception, cutaneous sensitivity, and muscle strength are 3 important contributors to balance control in older adults. The relationship that dynamic and static balance control has to proprioception, cutaneous sensitivity, and muscle strength is still unclear. This study was performed to investigate the relationship these contributors have to dynamic and static balance control.MethodsA total of 164 older adults (female = 89, left dominant = 15, age: 73.5 ± 7.8 years, height: 161.6 ± 7.1 cm, weight: 63.7 ± 8.9 kg, mean ± SD) participated in this study. It tested the proprioception of their knee flexion/extension and ankle dorsi/plantarflexion, along with cutaneous sensitivity at the great toe, first and fifth metatarsals, arch, and heel, and the muscle strength of their ankle dorsi/plantarflexion and hip abduction. The Berg Balance Scale (BBS) and the root mean square (RMS) of the center of pressure (CoP) were collected as indications of dynamic and static balance control. A partial correlation was used to determine the relationship between the measured outcomes variables (BBS and CoP-RMS) and the proprioception, cutaneous sensitivity, and muscle strength variables.ResultsProprioception of ankle plantarflexion (r = –0.306, p = 0.002) and dorsiflexion (r = –0.217, p = 0.030), and muscle strength of ankle plantarflexion (r = 0.275, p = 0.004), dorsiflexion (r = 0.369, p < 0.001), and hip abduction (r = 0.342, p < 0.001) were weakly to moderately correlated with BBS. Proprioception of ankle dorsiflexion (r = 0.218, p = 0.020) and cutaneous sensitivity at the great toe (r = 0.231, p = 0.041) and arch (r = 0.285, p = 0.002) were weakly correlated with CoP-RMS in the anteroposterior direction. Proprioception of ankle dorsiflexion (r = 0.220, p = 0.035), knee flexion (r = 0.308, p = 0.001) and extension (r = 0.193, p = 0.040), and cutaneous sensitivity at the arch (r = 0.206, p = 0.028) were weakly to moderately correlated with CoP-RMS in the mediolateral direction.ConclusionThere is a weak-to-moderate relationship between proprioception and dynamic and static balance control, a weak relationship between cutaneous sensitivity and static balance control, and a weak-to-moderate relationship between muscle strength and dynamic balance control.     

会话应答结构中话语标记语的语用特征

在会话应答结构模式中,一个邻近对的第二部分可能是结构形态简单的期待应答,也可能是结构形态复杂的不期待应答。文章以话语标记语为研究对象,考察其在会话应答结构模式中的语用表现。话语标记语可以有效减弱不期待应答言语行为的施为用意,同时也指出了某些话语标记语在期待应答中具有增强言语行为施为用意的效果。     

个性化学习中的机助自适应测试系统设计

为实现"计算机原理"课程计算机辅助教学中的个性化学习和检验,提高学生的自学能力、创造精神和学习效率,在VB 6.0和Access 2003环境下,开发基于IRT模型"计算机原理"课程的自适应测试系统——CoCAT.整个系统分为3个模块:系统管理模块、试题管理模块和测试管理模块,它可根据学生特点自动选择合适的试题,并提供学生学习能力和学习效果等方面的分析报告,可以更真实地反映学习者的学习水平和特点,有利于学生自学习和自检验.与传统的考试方式相比,具有效率高、题目的选择和评分灵活等特点,测试结果能更精确地反映被试者的实际水平,更适合在网络教育尤其是个性化学习中应用.     

常熟历史文化旅游开发研究

历史文化旅游产品的开发,不仅可以提升城市的文化底蕴与文化品位,还有助于城市的物质与精神文明建设。常熟作为江苏省县级市中唯一的“国家历史文化名城”,拥有丰富的历史文化资源。如何利用这一资源优势,更好地为常熟地方经济社会发展服务是值得思考的重大问题。     

"学习型社会"的挑战与高等教育的应答

"学习型社会"是一种表达终身学习理念的社会形态.较之传统型社会形态,"学习型社会"在知识、学习、学习者、时间、空间等内涵特征方面发生了实质性变化,这种变化对高等教育的目标、对象、内容和方式提出了挑战.而高等教育对学习型社会具有正反双重价值影响,应从办学理念与机制两方面做出理性的应答:从理论层面看,应明确我国高等教育办学理念;从实践层面看,应改革我国高等教育办学机制.     

Analysis on Reader Response Criticism Based on A Rose For Emily

Plots and characters being centered as something never mentioned before,Faulkner designed images so as to maintain his works stable and open to construct a tensile space for imagination. Readers could ...     

Five Methods for Estimating Angoff Cut Scores with IRT

This article illustrates five different methods for estimating Angoff cut scores using item response theory (IRT) models. These include maximum likelihood (ML), expected a priori (EAP), modal a priori (MAP), and weighted maximum likelihood (WML) estimators, as well as the most commonly used approach based on translating ratings through the test characteristic curve (i.e., the IRT true‐score (TS) estimator). The five methods are compared using a simulation study and a real data example. Results indicated that the application of different methods can sometimes lead to different estimated cut scores, and that there can be some key differences in impact data when using the IRT TS estimator compared to other methods. It is suggested that one should carefully think about their choice of methods to estimate ability and cut scores because different methods have distinct features and properties. An important consideration in the application of Bayesian methods relates to the choice of the prior and the potential bias that priors may introduce into estimates.