Transit smart card data mining for passenger origin information extraction

The automated fare collection(AFC) system,also known as the transit smart card(SC) system,has gained more and more popularity among transit agencies worldwide.Compared with the conventional manual fare collection system,an AFC system has its inherent advantages in low labor cost and high efficiency for fare collection and transaction data archival.Although it is possible to collect highly valuable data from transit SC transactions,substantial efforts and methodologies are needed for extracting such data because most AFC systems are not initially designed for data collection.This is true especially for the Beijing AFC system,where a passenger’s boarding stop(origin) on a flat-rate bus is not recorded on the check-in scan.To extract passengers’ origin data from recorded SC transaction information,a Markov chain based Bayesian decision tree algorithm is developed in this study.Using the time invariance property of the Markov chain,the algorithm is further optimized and simplified to have a linear computational complexity.This algorithm is verified with transit vehicles equipped with global positioning system(GPS) data loggers.Our verification results demonstrated that the proposed algorithm is effective in extracting transit passengers’ origin information from SC transactions with a relatively high accuracy.Such transit origin data are highly valuable for transit system planning and route optimization.     

Diffusion tensor interpolation profile control using non-uniform motion on a Riemannian geodesic

Tensor interpolation is a key step in the processing algorithms of diffusion tensor imaging (DTI), such as registration and tractography. The diffusion tensor (DT) in biological tissues is assumed to be positive definite. However, the tensor interpolations in most clinical applications have used a Euclidian scheme that does not take this assumption into account. Several Rie-mannian schemes were developed to overcome this limitation. Although each of the Riemannian schemes uses different metrics, they all result in a ‘fixed’ interpolation profile that cannot adapt to a variety of diffusion patterns in biological tissues. In this paper, we propose a DT interpolation scheme to control the interpolation profile, and explore its feasibility in clinical applications. The profile controllability comes from the non-uniform motion of interpolation on the Riemannian geodesic. The interpolation experiment with medical DTI data shows that the profile control improves the interpolation quality by assessing the reconstruction errors with the determinant error, Euclidean norm, and Riemannian norm.     

A note on circle packing

The problem of packing circles into a domain of prescribed topology is considered. The circles need not have equal radii. The Collins-Stephenson algorithm computes such a circle packing. This algorithm is parallelized in two different ways and its performance is reported for a triangular, planar domain test case. The implementation uses the highly parallel graphics processing unit (GPU) on commodity hardware. The speedups so achieved are discussed based on a number of experiments.     

重症监护病房紧急状况预警算法

重症监护病房中的病人身体状况通常很不稳定,常出现各种需要医护人员介入治疗的紧急状况。由于医疗资源有限,医护人员可能无法及时发现并处理这些紧急状况,给病人的存活率带来严重的负面影响。如果可以预测这些紧急状况的发生,并及时通知相关医护人员,将大大提高病人的存活率。常见重症监护病房紧急状况包括突然死亡、败血症、肺部感染、急性低血压、以及器官衰竭等。紧急状况预警建模主要采用病人的长时间生命体征监测数据,预测在一定时间之后发生某种紧急状况的可能性。预警模型所采用的监测数据分为静态数据、事件数据和时间序列数据等三类。静态数据具有容易采集、但预测准确性偏低的特点。事件数据或时间序列数据、以及多种类型数据的混合数据对于紧急状况预警模型的预测性能的提高有重要作用,将会获得更广泛的应用。     

联合相关反馈在医学图像检索中的应用

为进一步提高基于内容的医学图像检索性能,本文对相关反馈算法和全局特征进行研究。将基于模糊区域特征的图像检索和相关反馈算法与基于SVM的相关反馈算法结合起来,对复杂的区域特征采用基于模糊区域特征相关反馈算法,对全局特征采用能同时使用正例和负例图像的基于SVM的相关反馈算法,提出联合相关反馈算法。实验结果表明,采用这些方法后,检索结果有了很大的提高。     

基于DMT的1553B带宽扩展研究

由于传统的MIL-STD-1553B总线难以满足高速数据传输需求且更换现有总线代价过高,因此迫切需要在不影响现有基带通信的条件下升级1553B系统以提供高速通信接口。本文分析1553B的信道特性并据此选择频谱利用率高、抗频率选择性衰落的离散多音调制(DMT)作为扩展带宽的技术,基于离散多音调制,提出一个与现有通信相互兼容的扩展方案以显著提高传输速率,并对该方案涉及的关键技术进行介绍。     

支持AirPrint功能的佳能腾彩PIXMA传真一体机

2012年4月9日,佳能（中国）有限公司发布腾彩PIXMA喷墨打印机新产品——传真一体机腾彩PIXMAMX898、PIXMAMX518．PIXMAMX438．相关产品搭载了多种连接方式与功能,希望能够帮助用户更加灵活地实现随时随地的打印输出。     

黑色，成就影像艺术E0S影像级专业喷墨照片打印机佳能腾彩PIXMAPRO-1隆重登场

佳能一直致力于为专业摄影市场提供世界一流的影像产品。 专业摄影追求对于色彩的细腻把握和精准表现,更追求对于光影的敏感捕捉和层次还原。佳能一直致力于为专业摄影市场提供世界一流的影像产品,而在更加专业与纯粹的黑白摄影领域,佳能（中国）有限公司于2012年9月313发布了一款针对EOS专业摄影用户的影像级专业喷墨照片打印机腾彩PIXMAPRO-1。它不仅延续了佳能腾彩PIXMAPRO系列专业喷墨照片打印机在色彩还原品质上的一贯优势,而且在黑白影调的输出处理上更精益求精,能够充分实现专业黑白摄影作品层次丰富而色调精准的打印输出。任由光影流转、色景变换,PRO-1皆能捕捉入微,为您臻藏影像艺术典范。     

索尼摄像机新品上市

2012年2月14日索尼（中国）有限公司发布了由11款高清摄像机组成的Handycam龙年新阵营。本次发布的新品拍摄性能更强大、分享乐趣更轻松、机身色彩更多。索尼首次在消费级摄像机上,     

数字温度计的制作

单片机在日用电子产品中的应用越来越广泛,温度测量是人们日常生活中常常需要测量和控制的一个量,本文采用AT89C51单片机和温度传感器DS18B20从硬件和软件两方面介绍了一款简易数字温度计的制作过程,并对硬件原理图和程序流程图作了简洁的描述.