Neck pain prevalence and associated occupational factors in Portuguese office workers

ObjectiveThis study aimed to assess the prevalence of neck pain and to identify associated occupational factors in Portuguese office workers.BackgroundThere is still necessary to quantify the association of the use of new technologies with neck pain in office workers.MethodsSix hundred-and-one office workers completed online questionnaires with questions related to anthropometric parameters, work-related variables, workstation setup, and musculoskeletal pain from the Portuguese version of the Standardized Nordic Musculoskeletal Questionnaire.ResultsThe prevalence of neck pain was 56.1%. An average of 35.6% of the office workers with neck pain reported pain in more than three body segments. The significantly risk factors were “age between 50 and 65” [OR: 1.92 (1.26–2.91) P = 0.002], “working without break for 2 h” [OR: 1.82 (1.00–3.31) P = 0.05], “more than 3 h” [OR: 2.41 (1.35–4.10) P = 0.003], screen localization not centered” [OR: 2.01 (1.01–4.00) P = 0.045], and “use of computer mouse more than 50% of the worktime” [OR: 2.05 (1.14–3.71) P = 0.017].ConclusionThere was a high prevalence of neck pain and a considerable number of painful body segments in office workers. Age, working without break, screen localization and the use of computer mouse where the significant risk factors associated with the development of neck pain.Relevance to industryA high prevalence of neck pain and number of areas with pain in office workers require a detailed pain mechanism assessment. There were associated occupational risk factors for the development of neck pain. Call for concerted actions to explore optimal and efficient management plans.     

A novel method for the classification of Alzheimer's disease from normal controls using magnetic resonance imaging

Alzheimer's disease (AD) is the most prevalent form of dementia. Although fewer people, who suffer from AD are correctly and promptly diagnosed, due to a lack of knowledge of its cause and unavailability of treatment, AD is more manageable if the symptoms of mild cognitive impairment (MCI) are in an early stage. In recent years, computer‐aided diagnosis has been widely used for the diagnosis of AD. The main motive of this paper is to improve the classification and prediction accuracy of AD. In this paper, a novel approach is developed to classify MCI, normal control (NC), and AD using structural magnetic resonance imaging (sMRI) from the Alzheimer's disease Neuroimaging Initiative (ADNI) dataset (50 AD, 50 NC, 50 MCI subjects). FreeSurfer is used to process these MRI data and obtain cortical features such as volume, surface area, thickness, white matter (WM), and intrinsic curvature of the brain regions. These features are modified by normalizing each cortical region's features using the absolute maximum value of that region's features from all subjects in each group of MCI, NC, and AD independently. A total of 420 features are obtained. To address the curse of dimensionality, the obtained features are reduced to 30 features using a sequential feature selection technique. Three classifiers, namely the twin support vector machine (TSVM), least squares TSVM (LSTSVM), and robust energy‐based least squares TSVM (RELS‐TSVM), are used to evaluate the classification accuracy from the obtained features. Five‐fold and 10‐fold cross‐validation are used to validate the proposed method. Experimental results show an accuracy of 100% for the studied database. The proposed approach is innovative due to its higher classification accuracy compared to methods in the existing literature.     

基于Multipath的煤矿巷道三维模型构建方法

针对现有煤矿巷道三维模型存在灵活性和可移植性差、数据更新维护困难等问题,提出了一种基于Multipath的煤矿巷道三维模型构建方法。该方法通过定义点弧拓扑数据模型,将煤矿CAD格式数据转换为Geodatabase中的要素类,利用开发的ArcGIS Engine程序、通过插入节点坐标生成巷道三维模型,实现了煤矿巷道自动建模,有效减少了巷道三维建模的工作量。     

Response correction techniques for surrogate‐based design optimization of microwave structures

Simulation‐based optimization has become an important design tool in microwave engineering. However, using electromagnetic (EM) solvers in the design process is a challenging task, primarily due to a high‐computational cost of an accurate EM simulation. In this article, we present a review of EM‐based design optimization techniques exploiting response‐corrected physically based low‐fidelity models. The surrogate models created through such a correction can be used to yield a reasonable approximation of the optimal design of the computationally expensive structure under consideration (high‐fidelity model). Several approaches using this idea are reviewed including output space mapping, manifold mapping, adaptive response correction, and shape‐preserving response prediction. A common feature of these methods is that they are easy to implement and computationally efficient. Application examples are provided. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.     

经食道心房调搏的放射性核素心血管造影

本文应用反符合电路剔除调搏脉冲干扰的方法,制成经食道心房调搏心电心音门电路触发装置,用于经食道心房调搏的核素心血管造影。参考Tzivoni标准,当逐级增加调搏心率至140次/min或亚极量心率后发现:冠心病人有调搏后EF降低;急性心肌梗塞病人EF减低更为明显,并呈室壁反向运动。因此,心房调搏核素心血管造影有助于冠心病,特别是心肌梗塞的诊断。     

CAD与CAPP集成研究回转体类零件特征识别

本文研究了回转体轴类,轴套类零件的特征识别。对这类零件常用的特征单元进行了定义,描述了这类零件的特征模型:介绍了它的识别方法和特征参数定义方法。     

多目标多约束的集成电路统计优化策略

对于集成电路设计、生产过程中的多目标、多约束统计优化问题,本文提出了“合格率足够高”的优化宗旨,并从概率论的基本原理出发,结合集成电路的特点,导出了一种合格率的近似表述方法,提出的变权重Monte Carlo法编程简便,效率高。采用这些优化策略设计的集成电路合格率优化系统取得了比较好的结果。     

基于标准件库的螺钉联接自适应设计

提出一种AutoCAD环境中基于标淮件库的螺钉联接自适应设计算法。利用螺钉和垫片以及被联接件之间设计信息的相关性自动确定装配方位及联接件的几何参数，自动检测和复原被联接件的剖面线，简化了设计过程。     

液压管路通用件参数化图库的设计与应用

在AutoCAD中利用Autolisp语言编程，通过数据存储和数据检索，将液压系统中常用的管路通用件编制成参数化图库，并用图标菜单调用绘图程序，实现参数化绘图，达到提高绘图效率的目的。     

基于VB的凸轮CAD系统的研究与开发

通过对凸轮轮廓曲线的分析，建立凸轮廓线的数学模型，采用圆弧逼近的等误差编程算法，以Visual Basic6．0作为开发工具，研究开发出一套具有良好人机界面的凸轮CAD系统。该系统实现了凸轮轮廓设计的无图纸化，提高了凸轮廓形的设计精度和设计效率，较好地满足了实际精度要求。