On the limitations of linear beams for the problems of moving mass-beam interaction using a meshfree method

This paper deals with the capabilities of linear and nonlinear beam theories in predicting the dynamic response of an elastically supported thin beam traversed by a moving mass. To this end, the discrete equations of motion are developed based on Lagrange＇s equations via reproducing kernel particle method （RKPM）. For a particular case of a simply supported beam, Galerkin method is also employed to verify the results obtained by RKPM, and a reasonably good agreement is achieved. Variations of the maximum dynamic deflection and bending moment associated with the linear and nonlinear beam theories are investigated in terms of moving mass weight and velocity for various beam boundary conditions. It is demonstrated that for majority of the moving mass velocities, the differences between the results of linear and nonlinear analyses become remarkable as the moving mass weight increases, particularly for high levels of moving mass velocity. Except for the cantilever beam, the nonlinear beam theory predicts higher possibility of moving mass separation from the base beam compared to the linear one. Furthermore, the accuracy levels of the linear beam theory are determined for thin beams under large deflections and small rotations as a function of moving mass weight and velocity in various boundary conditions.

开放存取期刊PLoS ONE网络出版模式研究

以PLoSONE为案例,分析开放存取期刊的可持续发展网络出版模式。较详细介绍了PLoSONE的出版准则、同行评审制度、运营模式、文献影响的学术评价方式、开放获取以及索引和存档。其出版前同行评审与出版后网上公开评议共存模式、以及快速发表特点,值得科技期刊界思考与借鉴。

女生体育精品课程建设中的思路与实践

在女生体育校级精品课程建设过程中,课程组从性别视角切入,融合多学科理论,首先在以挖掘女生内在潜质、尊重女生个性发展、引导女生自我完善的女生体育教学育人理念上取得了共识;其次在实践教学中以身体练习为主要手段,通过增加时尚流行类运动项目教学内容、扩充女性身体保健与解读女性气质等知识点,着重增强女生体质健康、提高体育素养和发展学生个性;再次通过实施网络教学互动平台为媒介的课内课外一体教学模式,增强课堂教学与课外活动的联系,有效发挥网络教学资源和师生交流共享平台的作用,培养并发展了学生的运动能力与体育自主实践能力,大大提高了教学质量,为现代教育技术手段与体育传统课堂教学的有效结合提供了思路和参考。

基于用户视角的手机游戏关键设计特征提取

目的探索影响手机游戏用户体验的关键设计特征,基于用户视角进行实验研究,为开发人员指明设计重点。方法首先通过10名被试循环对比两组用户体验水平不同的手机游戏,确立出30项影响手机游戏用户体验的设计特征;其次邀请46名被试对32款游戏的用户体验水平和30项设计特征的实现程度进行评分,利用BP神经网络算法计算设计特征对于用户体验和各维度水平的相对重要度。结果贡献率前十的设计特征共计解释手机游戏57.10%、52.74%、61.07%、62.48%、52.63%、56.01%、59.72%的用户体验、反馈、沉浸、挑战、社交、移动以及控制的感知水平。结论用户体验与各维度间的关键设计特征存在差别,该方法有助于为手机游戏设计人员指明影响用户体验的设计重点,合理分配游戏开发资源。

构式特征在构式化过程中的互动、机制与结果

本文立足于多重互动观,以汉语副词主导构式为例,分析了构式特征在构式化中的互动过程、机制与结果。根据常项构件数量或位置是否变化将构式化结果分为恒棂构式和变棂构式,并归纳出前者的链条式与辐射式发展路径和后者的单轮与多轮构式化的发展类型。同时,探讨了“构-境-人”塔式互动关系格局,阐述了特征互动调变的具体实现机制,刻画了构式特征在构式化中的具体调变过程和机制,并使用由各层次构式特征构成的合力网络直观展示该调变过程。最后,根据构式集共享特征的类型,将构式联结分为基于共享形式特征和基于共享意义特征两类,二者分别可通过形式增扩和替换常项机制实现。

Exploiting the Capabilities of the Interconnection Network on Dawning-1000

On Dawning-1000, the two-dimension mesh interconnection network enables low-latency, high-bandwidth communication, however, these capabilities have not been realized because of the high processing overhead imposed by existing com- munication software. Active Messages provide an efficient communication mecha nism with small overhead, which may expose the raw capabilities of the underlying hardware. In addition, one of the most promising techniques, user-level communi- cation, is often used to improve the performance of the traditional protocols such as TCP and UDP, and is also adopted in implementing the novel abstractions like Active Messages. Thus a user-level Active Messages model is designed and imple- mented on Dawning-1000. Preliminary experiments show that the combination of Active Messages mechanism and user-level communication technique is quite efficient in reducing software overhead associated with sending and receiving messages and in exploiting the capabilities of the interconnection network.