Performance evaluation of priority CSMA-CA mechanism on ISA100.11a wireless network

The International Society of Automation recently released ISA100.11a as an open standard for reliable wireless networks for industrial automation. ISA100.11a uses the TDMA scheme in the medium access layer to provide deterministic services. However, ISA100.11a adopts the CSMA-CA mechanism with priorities for retransmission from failure on dedicated links, sporadic data, and network configuration.This paper evaluates ISA100.11a CSMA-CA by simulation, considering the effects of backoff procedures and priority settings to probability of collision and successful use of slots. It's demonstrated that a high number of priority classes enable better network utilization resulting in less number of packets exceeding their lifetime.     

A global localization approach based on Line-segment Relation Matching technique

This paper presents a novel global localization approach for mobile robots by exploring line-segment features in any structured environment. The main contribution of this paper is an effective data association approach, the Line-segment Relation Matching (LRM) technique, which is based on a generation and exploration of an Interpretation Tree (IT). A new representation of geometric patterns of line-segments is proposed for the first time, which is called as Relation Table. It contains relative geometric positions of every line-segment respect to the others (or itself) in a coordinate-frame independent sense. Based on that, a Relation-Table-constraint is applied to minimize the searching space of IT therefore greatly reducing the processing time of LRM. The Least Square algorithm is further applied to estimate the robot pose using matched line-segment pairs. Then a global localization system can be realized based on our LRM technique integrated with a hypothesis tracking framework which is able to handle pose ambiguity. Sufficient simulations were specially designed and carried out indicating both pluses and minuses of our system compared with former methods. We also presented the practical experiments illustrating that our approach has a high robustness against uncertainties from sensor occlusions and extraneous observation in a highly dynamic environment. Additionally our system was demonstrated to easily deal with initialization and have the ability of quick recovery from a localization failure.     

Geoadditive expectile regression

Quantile regression has emerged as one of the standard tools for regression analysis that enables a proper assessment of the complete conditional distribution of responses even in the presence of heteroscedastic errors. Quantile regression estimates are obtained by minimising an asymmetrically weighted sum of absolute deviations from the regression line, a decision theoretic formulation of the estimation problem that avoids a full specification of the error term distribution. Recent advances in mean regression have concentrated on making the regression structure more flexible by including nonlinear effects of continuous covariates, random effects or spatial effects. These extensions often rely on penalised least squares or penalised likelihood estimation with quadratic penalties and may therefore be difficult to combine with the linear programming approaches often considered in quantile regression. As a consequence, geoadditive expectile regression based on minimising an asymmetrically weighted sum of squared residuals is introduced. Different estimation procedures are presented including least asymmetrically weighted squares, boosting and restricted expectile regression. The properties of these procedures are investigated in a simulation study and an analysis on rental fees in Munich is provided where the geoadditive specification allows for an analysis of nonlinear effects of the size of flats or the year of construction and the spatial distribution of rents simultaneously.     

云南大学生体育兴趣及差异调查研究

对云南高校大学生体育兴趣程度及差异现状的调查结果表明：云南大学生体育兴趣总体兴趣程度较好,男女生体育兴趣程度差异明显,少数民族学生与汉族学生、城市生源学生与农村生源学生、独生子女学生与非独生子女学生体育兴趣程度有一定差异,但差异不明显。通过分析和研究大学生体育兴趣及差异的主要表现,提出加强大学生体育兴趣培养的建议。     

Application of a.c. impedance technique to the study of the proton diffusion process in the porous MnO2 electrode

The proton diffusion coefficient in γ-MnO₂ at various stages of discharge of an electrolytic manganese dioxide electrode has been determined taking into consideration the true molar volume and the electrochemically accessible surface area of MnO₂. The unique electrochemical cell which allows the electrode expansion during the discharge to be monitored in situ was reported. The a.c. impedance technique and the transmission line equivalent circuit were used. Electrode ohmic resistance, Faradaic resistance, and double-layer capacitance were also obtained by means of numerical fitting of the impedance data using the transmission line model.     

Development of a Reconfigurable Platform for Manufacturing Equipment Control

In modern manufacturing equipment control area,controller is required to deliver higher computing capability for adopting advanced algorithms to meet speed and accuracy requirements,and reconfigurabilities for changing or(and)adding features or functions.This paper presents a methodology in design and implementation of a high performance and reconfigurable platform for manufacturing equipment control.This methodology is in virtue of system on a programmable chip(SoPC)technolo- gy but replacing the on-chip processor by an external high performance,floating-point digital signal processor(DSP).The appli- cation of the DSP is designed as a multi-threaded framework,which has more flexibilities than a traditional single-loop one.Fur- thermore,the field programmable gate array(FPGA)system can be reconfigured easily and quickly to meet a new requirement by dragging and dropping pre-built components in a SoPC building environment.As a result,the controller platform is more recon- figurable in terms of algorithms and functions.This platform is implemented in a 3-axis milling machine control and the result indicates that the design and implementation presented in this paper is feasible.     

"脂粉英雄"王熙凤的服饰--《红楼梦》服饰研究系列之一

作为"脂粉队里的英雄",王熙凤的服饰是<红楼梦>所有女性人物中描写最丰富最精彩的.其意义主要有三:凸现王熙凤的强女人的鲜明个性;凸现作为少妇丽人的王熙凤的精神风貌;体现"正邪两赋"的王熙凤的幸福观的新质.     

故障树辅助建树专家系统

故障树辅助建树专家系统（FTES）是基于本地机数据库的图形界面软件，其目标是辅助建造核电站流体系统故障树模型，本系统应用了逐级上溯和标准化了树的概念，综合应演绎法和合成法进行建树推理，系统具有典型的专家系统结构，通过应用辅助建树软件能够提高一级PSA的质量。     

XML模式的扩展研究

XML是目前已被广泛采用的WWW上信息交换和表示的技术之一，被称为Internet时代的通用数据格式。首先针对现有的XML语法进行了抽象及封闭性分析，得到了扩展XML语法，然后开发了一个分析器，对由此扩展语法生成的对象进行分析，实验表明，扩展后的XML语法具有较W3C规范的XML语法有更一般的表现力。     

适用于Living PSA的故障树求解方法

Living PSA是当前核电厂的安全分析与评价中最热点的问题之一，Living PSA实现中最为根本而又关键的问题是“速度”问题：在现有PSA方法的基础上，根据Living PSA的特性，设计了一种适用于Living PSA的故障树求解方法，即独立模块排序求解法，并通过例子详细地说明了该方法实现过程：这个方法除了能快速地求解故障树以外，当故障树结构或故障树中部件可靠性模型或数据发生变化时能实时地求解故障树。