自适应天线匹配低频RFID读写器设计

在工业现场、野外甚至水中,RFID读写器天线电特性参数将发生改变,导致阻抗不匹配和发射功率大幅下降,最终降低RFID读写器读写范围和效率。为了解决这个问题,构建了一个自适应天线匹配RFID读写器系统,该系统在基本读写器系统上增加了自适应电容匹配矩阵、正弦波均方根检测和模/数转换器。该系统通过依次配置电容矩阵,扫描天线发射信号幅度,检测出最佳匹配电容,实现天线阻抗的最佳匹配。通过实验表明,在一定范围内该系统能够实现自动的阻抗匹配,获取最大发射功率。     

Multivariable adaptive control: A survey

Adaptive control is a control methodology capable of dealing with uncertain systems to ensure desired control performance. This paper provides an overview of some fundamental theoretical aspects and technical issues of multivariable adaptive control, and a thorough presentation of various adaptive control schemes for multi-input–multi-output systems, literature reviews on adaptive control foundations and multivariable adaptive control methods, and related technical problems. It covers some basic concepts and issues such as certainty equivalence, stability, tracking, robustness, and parameter convergence. It discusses some of the most important topics of adaptive control: plant uncertainty parametrization, stable controller adaptation, and design conditions for different adaptive control schemes. The paper also presents a detailed study of well-developed multivariable model reference adaptive control theory and design techniques. It provides an introduction to multivariable adaptive pole placement and adaptive nonlinear control, and it concludes by identifying some open research problems.     

Augment low-field intra-operative MRI with preoperative MRI using a hybrid non-rigid registration method

Background

Preoperatively acquired diffusion tensor image (DTI) and blood oxygen level dependent (BOLD) have been proved to be effective in providing more anatomical and functional information; however, the brain deformation induced by brain shift and tumor resection severely impairs the correspondence between the image space and the patient space in image-guided neurosurgery.

Method

To address the brain deformation, we developed a hybrid non-rigid registration method to register high-field preoperative MRI with low-field intra-operative MRI in order to recover the deformation induced by brain shift and tumor resection. The registered DTI and BOLD are fused with low-field intra-operative MRI for image-guided neurosurgery.

Results

The proposed hybrid registration method was evaluated by comparing the landmarks predicted by the hybrid registration method with the landmarks identified in the low-field intra-operative MRI for 10 patients. The prediction error of the hybrid method is 1.92 ± 0.54 mm, and the compensation accuracy is 74.3 ± 5.0%. Compared to the landmarks far from the resection region, those near the resection region demonstrated a higher compensation accuracy (P-value = .003) although these landmarks had larger initial displacements.

Conclusions

The proposed hybrid registration method is able to bring preoperatively acquired BOLD and DTI into the operating room and compensate for the deformation to augment low-field intra-operative MRI with rich anatomical and functional information.     

Event-driven,pattern-based methodology for cost-effective development of standardized personal health devices

Experiences applying standards in personal health devices (PHDs) show an inherent trade-off between interoperability and costs (in terms of processing load and development time). Therefore, reducing hardware and software costs as well as time-to-market is crucial for standards adoption. The ISO/IEEE11073 PHD family of standards (also referred to as X73PHD) provides interoperable communication between PHDs and aggregators. Nevertheless, the responsibility of achieving inexpensive implementations of X73PHD in limited resource microcontrollers falls directly on the developer. Hence, the authors previously presented a methodology based on patterns to implement X73-compliant PHDs into devices with low-voltage low-power constraints. That version was based on multitasking, which required additional features and resources. This paper therefore presents an event-driven evolution of the patterns-based methodology for cost-effective development of standardized PHDs. The results of comparing between the two versions showed that the mean values of decrease in memory consumption and cycles of latency are 11.59% and 45.95%, respectively. In addition, several enhancements in terms of cost-effectiveness and development time can be derived from the new version of the methodology. Therefore, the new approach could help in producing cost-effective X73-compliant PHDs, which in turn could foster the adoption of standards.     

环境保护与汽车涂装

叙述了与汽车涂装相关的国际环保法规及汽车涂装的公害,重点介绍了汽车用环保型涂料、5R活动和3C1B涂装技术等环保达标措施.     

柳州,云浮,宣化三厂预热分解系统技术改进经验引起的思考

本文分析了柳州、云浮、宣化三厂预分解系统粘结堵塞、难以稳定生产和不能“达产达标”的原因,逐一介绍了三厂预分解系统技术改进的措施和效果,并就其技改工程经验进行了分析总结和探索思考.     

结合相关规则和本体加权图的查询扩展

针对现有信息检索系统查询性能的不足,提出了一种结合相关规则和WordNet本体信息的查询扩展方法.该方法借助相关规则挖掘和WordNet本体信息构建加权词语关系图,并根据加权图的结构和权重信息计算扩展词的重要性.查询时,从这个图中取原查询词的最邻近词作为扩展词来源,选取其中权重最大的p个词返回并进行二次检索.在实现算法的基础上,通过Lucene全文检索器进行实验,将所得的结果值F1与其他算法的结果作比较.比较结果表明,该方法比不作扩展的检索有约16.93％的性能提升.     

图的点可区别边染色算法研究

针对一般图设计了一种新型的点可区别边染色算法。该算法把概率思想和图染色相结合, 根据点可区别边染色的约束规则确立目标函数, 利用交换规则逐步寻优, 当目标函数的值满足要求时染色成功。给出详细算法步骤并进行了测试和分析, 实验结果表明该算法可以求出满足猜想的点可区别边色数。     

基于像素点的碎片图像拼接技术

针对一页规则的既纵切又横切的中文文件碎片和一页规则的双面打印的英文文件碎片,分别提出了一种基于行列图像的碎片匹配算法和二维图像成片连接匹配算法。首先将碎片边缘像素点转化成灰度值,然后对各碎片的灰度值进行匹配度研究,且将匹配度作为碎片之间拼接的依据,最后使用相应的算法计算机按碎片拼接顺序输出碎片号。通过实验分析表明,该算法能够更快地获得碎片拼接结果,大大提高拼接复原效率。