Comparison of multiple linear regression and artificial neural network in developing the objective functions of the orthopaedic screws

Optimizing the orthopaedic screws can greatly improve their biomechanical performances. However, a methodical design optimization approach requires a long time to search the best design. Thus, the surrogate objective functions of the orthopaedic screws should be accurately developed. To our knowledge, there is no study to evaluate the strengths and limitations of the surrogate methods in developing the objective functions of the orthopaedic screws. Three-dimensional finite element models for both the tibial locking screws and the spinal pedicle screws were constructed and analyzed. Then, the learning data were prepared according to the arrangement of the Taguchi orthogonal array, and the verification data were selected with use of a randomized selection. Finally, the surrogate objective functions were developed by using either the multiple linear regression or the artificial neural network. The applicability and accuracy of those surrogate methods were evaluated and discussed. The multiple linear regression method could successfully construct the objective function of the tibial locking screws, but it failed to develop the objective function of the spinal pedicle screws. The artificial neural network method showed a greater capacity of prediction in developing the objective functions for the tibial locking screws and the spinal pedicle screws than the multiple linear regression method. The artificial neural network method may be a useful option for developing the objective functions of the orthopaedic screws with a greater structural complexity. The surrogate objective functions of the orthopaedic screws could effectively decrease the time and effort required for the design optimization process.     

基于ZigBee技术的远端通信站监控系统及其实现

提出了一种基于ZigBee技术的远端通信站环境监控系统设计方案。包括系统结构、Zigbee通信接口、单片微处理器、温度采集等模块的软硬件设计。此方案设计的监测系统已在某远端无人小型频谱监测站使用。     

基于Web的企业信息管理系统安全方案

分析了传统企业信息管理系统存在的安全问题,应用SSL协议、网络型人侵检测系统、虚拟专用网等技术,提出了一种新的企业信息管理系统安全设计方案。理论分析和实验结果表明,新方案是保证企业信息管理系统安全运行的一种有效方案。     

The locally definable property of the product control structure

In this paper, the control structures and control technologies in decentralized discrete event control system are investigated. It shows that if the control structures on two local systems are standard and locally definable, so is the product control structure. Furthermore, a control technology associated with the product control structure is also given     

GPS定位技术在灌区调查中的应用

GPS定位技术日益成熟,在很多领域已得到了广泛应用。文中主要简介说明GPS技术原理与特点,针对工程实践中调查灌区的实际情况存在灌区面积大、渠系长、渠系建筑物多、渠道实际完成不连续的特点,采用传统的测量方法已无法满足快速而准确的调查要求,因此应用GPS定位技术与之比较,同时也验证了新技术的高效性和准确性。     

空载变压器投运电压不平衡问题的探讨

空载投入变压器,从低压侧加压,高压侧相电压出现不平衡;而从高压侧加压,低压侧出现相电压不平衡,两种状态下线电压均平衡。此现象是什么原因造成,能否投入运行?是否影响发电机并列?就空载变压器投运电压不平衡问题进行探讨,得出在变压器各种试验满足规程要求的前提下,测得空载变压器线电压平衡,用户可以放心使用,对电气设备和发电机并列不会有什么影响。     

代用碱JT的制备与应用性能研究

通过测定不同碱剂的缓冲容量,筛选并制备染色代用碱JT,并将其用于棉织物活性染料固色中。研究染浴中代用碱JT的组分对染色效果的影响,确定代用碱JT的组分为碳酸钾35%、硅酸钠50%、氢氧化钾10%和三乙醇胺5%。研究结果表明：代用碱替代纯碱用于活性染料固色,操作简单,染液pH值变化较小,且可提高染色牢度,节约用水,节约染色时间,降低综合成本。     

微波消解-石墨炉原子吸收光谱法测定芦笋中的铜、铅、镉和铬

建立微波消解-石墨炉原子吸收光谱法测定芦笋中Cu,Pb,Cd和Cr的方法。研究了微波消解体系和消解条件对消解效果的影响,选择HNO3-H2O2-H2O体系和梯度增压方式,得到较好的消解效果;研究了磷酸二氢铵溶液的质量浓度、灰化温度、原子化温度对吸光度的影响。通过单因素试验,分别确定了测定Cu,Pb,Cd和Cr时各自的最佳条件。在此条件下,测定芦笋中Cu,Pb,Cd和Cr含量分别为15.2,5.64,0.314和1.72μg/g,精密度分别为3.81%,2.80%,2.35%和2.92%,检出限分别为3.37,2.91,0.21和0.76ng/mL,加标回收率分别为92.5%,106.0%,102.5%和97.0%。微波消解-石墨炉原子吸收光谱法测定芦笋中Cu,Pb,Cd和Cr,方法快速、准确、污染少,具有较高的实用价值。