非线性支持向量回归在航空发动机性能参数预测中的应用

基于飞参数据的航空发动机的状态监控,是当前航空领域应用研究的热点之一。介绍了支持向量机回归理论,并用支持向量回归机和飞参数据对航空发动机特征参数（转差率S）进行了预测。计算结果表明,支持向量机回归方法具有很好的学习能力和预测能力。     

XML 数据流上Top-K 关键字查询处理

利用关键字可以在模式未知的情况下对XML数据进行查询.在当前的XML数据流上的关键字查询处理中,打分函数往往不能都满足各种用户不同的需求.提出了一种基于skyline的XML数据流上的Top-K关键字查询.对于这种查询,不需要考虑影响结果与查询相关性的复杂因素,只需利用skyline挑选与查询最相关的结果.提出了两种XML数据流上的有效的基于skyline的Top-K关键查询处理算法,包括对单查询和多查询的处理算法.通过扩展实验对两种算法的有效性和可扩展性进行了验证.经过实验验证,所提出的查询处理算法的效率几乎不受关键字个数、查询结果数量、查询数量等参数的影响,运行时间和文档大小大致呈线性关系.     

基于DSmT的机载目标断续航迹关联

针对机载目标跟踪中常见的目标航迹断续问题,将多传感器获得的目标属性与状态等多特征信息相结合,建立中断前后各航迹段组合的关联统计量,以各特征关联度为证据并基于DSm理论进行合成,根据识别结果对同一目标中断前后的航迹段进行关联,提高航迹连续性并降低战场态势复杂度。仿真结果表明了该方法的有效性与可行性。     

无线传感器网络基于路径的非均匀分布策略

无线传感器网络中多对一的数据传输方式导致节点负载的不均衡性,靠近汇聚节点(Sink)的节点要比远离Sink的节点消耗更多的能量,如此容易引发能量空洞问题。针对该问题,从网络数据的传递路径出发,根据网络中节点承担的路径数量的不同,平衡各层节点的能耗,提出感知节点覆盖率一致、内层路由节点与其所有外层感知节点数目相同的的非均匀分布策略,并通过仿真实验证明了该方法的有效性。     

基于隐Lyapunov 函数的软变结构控制: 一种控制策略

针对变结构控制的抖振问题,基于隐Lyapunov函数,提出一种新的控制策略:软变结构控制.首先给出软变结构控制的定义和控制器的构造方法;然后设计软变结构控制器和隐Lyapunov区域,给出了控制不受限和控制受限两种情形的软变结构控制,同时,分析了带有状态观测器的软变结构控制.软变结构控制是无滑模的变结构控制,能有效削弱抖振,保持高速调节速度和缩短趋近时间.仿真实例表明了该方法的有效性和可行性.     

Performance comparison of artificial neural network and logistic regression model for differentiating lung nodules on CT scans

PurposeTo compare the diagnostic performances of artificial neural networks (ANNs) and multivariable logistic regression (LR) analyses for differentiating between malignant and benign lung nodules on computed tomography (CT) scans.MethodsThis study evaluated 135 malignant nodules and 65 benign nodules. For each nodule, morphologic features (size, margins, contour, internal characteristics) on CT images and the patient’s age, sex and history of bloody sputum were recorded. Based on 200 bootstrap samples generated from the initial dataset, 200 pairs of ANN and LR models were built and tested. The area under the receiver operating characteristic (ROC) curve, Hosmer–Lemeshow statistic and overall accuracy rate were used for the performance comparison.ResultsANNs had a higher discriminative performance than LR models (area under the ROC curve: 0.955 ± 0.015 (mean ± standard error) and 0.929 ± 0.017, respectively, p < 0.05). The overall accuracy rate for ANNs (90.0 ± 2.0%) was greater than that for LR models (86.9 ± 1.6%, p < 0.05). The Hosmer–Lemeshow statistic for the ANNs was 8.76 ± 6.59 vs. 6.62 ± 4.03 (p > 0.05) for the LR models.ConclusionsWhen used to differentiate between malignant and benign lung nodules on CT scans based on both objective and subjective features, ANNs outperformed LR models in both discrimination and clinical usefulness, but did not outperform for the calibration.     

A habituating blood glucose control strategy for the critically ill

In the intensive care unit patients benefit from being fed and from having well controlled glucose levels. Insulin and glucose infusion serves as manipulated inputs to regulate blood glucose, while glucose infusion serves as a sole nutritional input. In this paper, a model predictive control strategy, based on simultaneously manipulating glucose and insulin infusion, is developed to improve blood glucose regulation in intensive care unit patients. In the short term, glucose infusion is used for tighter glucose control, particularly for disturbance rejection, while, in the long-term (24 h period), glucose infusion is used to meet nutritional needs. The “habituating control” algorithm is proposed and tested against a model predictive control (MPC) strategy that only manipulates insulin. The simulation results indicate that the Habituating MPC strategy outperforms the single input–single output MPC by providing faster setpoint tracking and tighter glucose control for a patient population, and producing less glucose variability while rejecting disturbances in insulin infusion and insulin sensitivity.     

一种TCP友好的无线多跳网络拥塞控制算法

为了改进流媒体在无线多跳网络中的传输质量,提出一种TCP友好的拥塞控制算法.该算法考虑了MAC层的信道竞争,节点通过标记数据包来通知数据流它的竞争状态,数据流基于所估计的竞争状态来控制传输速率.仿真结果表明所提出的算法能更有效地利用带宽,与已存在的算法相比,有较高的吞吐量和较好的平滑性.     

多信道多跳无线网络端到端时延最小化路由评价指标的研究

提出一种适用于多接口多信道无线网络的路由评价指标,DSRM.与传统的评价指标单纯注重网络吞吐量相比,DSRM采用整条路径的端到端时延作为评价指标,以适应日益频繁的时延敏感的应用需求.在DSRM中,综合考虑了网络传输过程中的竞争接入时延、基于等效带宽计算的传输时延、节点内的信道队列因素,并分析了整条路径的端到端重传时延.通过Qualnet仿真,证明了DSRM较WCETT、WEED等路由评价指标在平均端到端时延等网络性能参数上有了明显提升.     

基于优化RANSAC算法的二次元快速稳定配准

针对检测零件缺陷的二次元光电检测仪的速度和稳定性要求,提出了一种加入预匹配的快速稳定的RASNSAC匹配方法.首先对零件图像轮廓区域矩分析以及轮廓多边形逼近以及对其CAD标准档进行解析计算得到图像轮廓和CAD图的重心、主轴方向以及特征点集,然后通过重心和主轴对零件图像和CAD图进行预匹配,最后利用RANSAC对预匹配后的特征点集进行快速匹配.实验结果表明,此改进算法显著地提高了图像的匹配速度和稳定性.