Predicting social cues during online discussions: Effects of evaluations and knowledge content

This study examined whether evaluations (agreements, disagreements), knowledge content (new ideas, justifications), or social cues (SCs) in recent messages affected a current message’s positive or negative SC during asynchronous, online discussions. Using statistical discourse analysis, we modeled 894 messages by 183 participants on 60 high school mathematics topics (typically eight people posted per topic) on a mathematics problem solving website not connected to any class or school. Results showed that recent agreements increased the likelihood of positive SC, whereas justifications reduced it. Disagreements increased the likelihood of negative SC, whereas new ideas reduced it. Meanwhile, recent positive or negative SCs did not affect the likelihood of a subsequent SC. Together, these results suggest that judicious use of positive SCs rather than negative SCs during disagreements can help students both construct knowledge and maintain social relationships.     

Performance analysis and optimization of MPI collective operations on multi-core clusters

Memory hierarchy on multi-core clusters has twofold characteristics: vertical memory hierarchy and horizontal memory hierarchy. This paper proposes new parallel computation model to unitedly abstract memory hierarchy on multi-core clusters in vertical and horizontal levels. Experimental results show that new model can predict communication costs for message passing on multi-core clusters more accurately than previous models, only incorporated vertical memory hierarchy. The new model provides the theoretical underpinning for the optimal design of MPI collective operations. Aimed at horizontal memory hierarchy, our methodology for optimizing collective operations on multi-core clusters focuses on hierarchical virtual topology and cache-aware intra-node communication, incorporated into existing collective algorithms in MPICH2. As a case study, multi-core aware broadcast algorithm has been implemented and evaluated. The results of performance evaluation show that the above methodology for optimizing collective operations on multi-core clusters is efficient.     

A new view of fuzzy ideals in \Upgamma-rings

By means of a kind of new idea, we redefine fuzzy ideals and fuzzy interior ideals in a $\Upgamma$ -ring and investigate some of their related properties. In particular, we show that the regular and semisimple $\Upgamma$ -rings can be described by using these kinds of generalized fuzzy ideals.     

Design of a modified repetitive-control system based on a continuous–discrete 2D model

This paper concerns the problem of designing a modified repetitive-control system for a class of strictly proper plants. Repetitive control involves two types of actions: control and learning; but the insertion of a low-pass filter in a modified repetitive controller, which is employed to guarantee the stability of the system, mixes the two actions together. In this paper, a continuous–discrete two-dimensional model is first constructed. Next, the continuity of repetitive control and Lyapunov stability theory are applied to the model to establish two linear-matrix-inequality (LMI) based sufficient stability conditions, one for the design of the cutoff angular frequency and one for the design of the feedback gains. The features of these conditions are exploited to develop an iterative algorithm that searches for the best combination of the maximum cutoff angular frequency of the low-pass filter and the feedback gains. A numerical example illustrates the design procedure and demonstrates the validity of the method.     

境外公共安全防恐培训的几点思考

境外公共安全防恐培训能够强化员工对境外公共安全工作的认识,提高应对境外公共安全突发事件的能力;能够普及境外公共安全管理知识,增强员工境外工作期间的个人安全意识和防卫自救能力能够制定并落实境外公共安全管理责任及措施。汉油田职培中心境外公共安全防恐培训进行了严谨的培训需求调研和定位,教材开发和内容设计更趋完善,教学方法形式多样,课件制作引人入胜,防恐演习更具针对性和实用性。但在教师的亲身体验、培训内容的选取、教学团队的师资培养、防恐演习场地设施和人员的限制等方面还需要改进。     

基于DSP的光栅分度盘及其光栅信号精细分

对提高光栅的细分准确度进行了研究,提出了一种正切与余切相结合的方法.针对实际光栅信号的不稳定性,利用光栅发讯头输出正切、余切信号峰峰值与直流电平的漂移,自动修正反正切与反余切的查找表格.该方法应用于精密倾光学分读盘测量系统,使细分误差仅与光栅信号第一个采样值和最后一个采样值的精度有关,与测量过程中的光栅信号采样值的误差无关,同时采用DSP处理采样数据,速度更快,并成功应用于光栅分读盘系统,精度为2″.     

基于视觉手势识别技术的智能窗帘研究

在Visual Studio 2010开发环境中以C++为编程语言,使用计算机视觉计算中的开源OpenCV库处理图像,判定手势运动方向,构造基于视觉手势识别技术的智能窗帘系统。通过调用Windows API函数实现PC与LPC2131之间的串口通信,从而通过控制步进电机的转动方向来实现窗帘的打开和关闭操作。系统具有人机交互界面良好、操作简单、窗帘的长度可自行设定等优点。     

Java中的持久性存储技术——JDBC和JDO

在实际的企业应用程序中,开发人员可以通过多种方式来实现数据的持久化存储。例如,使用Java序列化并存储整个对象的二进制表示;较通用的企业方案是通过EJB来使用应用程序服务器的工具;或者使用JDBC存储在数据库中,还有就是通过JDO。文中主要介绍了JDBC和JDO技术,并把JDBC和JDO作了比较,讨论了各自的特性和不同点,并突出了常见的误解。最后得出一般性的结论:它们是互补的API,每个都为各自的目的而很好地服务。     

模糊免疫PID控制在铁芯卷绕纠偏中的应用

本文将模糊控制和免疫反馈机理与传统的PID控制相结合,设计了一种模糊免疫PID控制器并将它应用在新型变压器卷铁芯成型卷绕纠偏控制系统中。仿真研究表明,该控制器具有使系统超调量小、调整时间短、鲁棒性好且算法简单等优点,可明显提高纠偏系统的性能。     

一种基于防汽车追尾的车载测距安全预警装置的研制

介绍了激光雷达测距原理，进而引入到测距系统中，构建了一车载测距预警系统，分析了系统核心模块的组成和基本原理并给出了程序框图。当车间距达到阈值时及时发出声光与语音信号，提醒司机注意，避免追尾事故的发生。