基于粒子滤波的WiFi行人航位推算融合室内定位

为提高室内定位的精度和稳定性,提出使用粒子滤波融合WiFi指纹定位和行人航位推算的室内定位算法。为减少复杂室内环境对WiFi指纹定位的影响,提出将支持向量机分类与回归相结合的两级WiFi指纹定位算法。在基于智能手持设备惯性传感器的行人航位推算中,为减少惯性传感器的误差以及人随意行走带来的影响,采用状态转换的方法识别行走周期并进行步数统计,提出根据实时加速度数据动态设置状态转换的参数,利用步长和垂直加速度之间的关系以及相邻步长之间的关系,应用卡尔曼滤波进行步长计算。仿真实验中,基于支持向量机的WiFi指纹定位的平均误差比最近邻居(NN)算法降低34.4%,比K最近邻居(KNN)算法降低27.7%。改进的行人航位推算的性能优于常用代表性计步软件和步长计算算法,而经过粒子滤波融合后估计的行走轨迹更加接近真实轨迹:直线行走平均误差为1.21 m,优于WiFi的3.18 m和航位推算的2.76 m;曲线行走平均误差为2.75 m,优于WiFi的3.77 m和航位推算的2.87 m。     

基于KELM的位置指纹室内定位方法研究

考虑到位置指纹的非线性特性,提出基于核极限学习机（KELM）的位置指纹定位方法。KELM以其快速学习的特点,同时拥有紧密的网络结构,有效解决传统定位算法离线学习时间长和鲁棒性差的问题。通过改变离线数据收集环境,采用不同Wi-Fi接入点作信号源来分析KELM算法的定位性能,实验结果表明,同等条件下与基本ELM、SVM和kNN等位置指纹定位方法相比,KELM表现出更好的定位能力。     

基于Linux的智能安防系统的设计

本文介绍一种基于S3c6410的无线网络视频安防系统的设计方案,该方案利用S3c6410进行核心控制,通过ov9650摄像头实现对外界图像的采集,通过HostUSB模块实现对视频数据的存储,通过WiFi实现无线网络视频数据的通信,通过GPRS实现短信的收发和彩信的发送。阐述该系统的工作原理、硬件构成及软件的设计方案。     

未来新技术的应用对消防通信网的影响

通过分析3G、WiFi、WiMAX和WBMA等新通信标准体系的有关技术指标和发展前景,对其应用于火场消防通信网的可行性进行了展望。     

Identification of the Geographical Origins of Pomelos Using Multielement Fingerprinting

Eighty pomelo samples and 80 soil samples were examined using a multielement component test to predict the geographical origins of pomelos produced in 4 regions (Sichuan, Chongqing, Fujian, and Guangxi Provinces) of China. The concentrations of 8 elements were determined by atomic absorption spectrometry. Ca, K, and Na were the most abundant elements. Principal component analysis (PCA) and linear discriminant analysis (LDA) were applied to reduce the dimensionality of the multielement data from 8 to 2 while retaining the highest possible variance. Using PCA and LDA, 69.66% and 91.30%, respectively, of the pomelo origins were classified correctly using multielement variables, along with 67.06% and 83.40% for soil multielement analysis. Results indicated that the LDA method was more effective for geographical origin classification than PCA. The results of the multielement component test demonstrated its capability to screen pomelo origins rapidly.     

Detection of Panax quinquefolius in Panax ginseng using 'subtracted diversity array'

BACKGROUND: Food adulteration remains a major global concern. DNA fingerprinting has several advantages over chemical and morphological identification techniques. DNA microarray‐based fingerprinting techniques have not been used previously to detect adulteration involving dried commercial samples of closely related species. Here we report amplification of low‐level DNA obtained from dried commercial ginseng samples using the Qiagen^? REPLI‐g^® Kit. Further, we used a subtracted diversity array (SDA) to fingerprint the two ginseng species, Panax ginseng and Panax quinquefolius, that are frequently mixed for adulteration. RESULTS: The two ginseng species were successfully discriminated using SDA. Further, SDA was sensitive enough to detect a deliberate adulteration of 10% P. quinquefolius in P. ginseng. Thirty‐nine species‐specific features including 30 P. ginseng‐specific and nine P. quinquefolius‐specific were obtained. This resulted in a feature polymorphism rate of 10.5% from the 376 features used for fingerprinting the two ginseng species. The functional characterization of 14 Panax species‐specific features by sequencing revealed one putative ATP synthase, six putative uncharacterized proteins, and two retroelements to be different in these two species. CONCLUSION: SDA can be employed to detect adulterations in a broad range of plant samples. Copyright © 2011 Society of Chemical Industry     

Modeling food matrix effects on chemical reactivity: Challenges and perspectives

ABSTRACT

The same chemical reaction may be different in terms of its position of the equilibrium (i.e., thermodynamics) and its kinetics when studied in different foods. The diversity in the chemical composition of food and in its structural organization at macro-, meso-, and microscopic levels, that is, the food matrix, is responsible for this difference. In this viewpoint paper, the multiple, and interconnected ways the food matrix can affect chemical reactivity are summarized. Moreover, mechanistic and empirical approaches to explain and predict the effect of food matrix on chemical reactivity are described. Mechanistic models aim to quantify the effect of food matrix based on a detailed understanding of the chemical and physical phenomena occurring in food. Their applicability is limited at the moment to very simple food systems. Empirical modeling based on machine learning combined with data-mining techniques may represent an alternative, useful option to predict the effect of the food matrix on chemical reactivity and to identify chemical and physical properties to be further tested. In such a way the mechanistic understanding of the effect of the food matrix on chemical reactions can be improved.     

Secure video distribution scheme based on partial encryption

In TV program distribution, the receiver's identification information is embedded into video data in order to trace illegal distributors, and video data are encrypted in order to protect the confidentiality against unauthorized users. In traditional method, the TV program is firstly fingerprinted, then encrypted, and finally transmitted. For N receivers, N times of encryption, and N times of fingerprinting operations are required, which makes the sender of high loading. In another method, the media content is decrypted and fingerprinted simultaneously by the joint fingerprint embedding and decryption, which is difficult to obtain reasonable performances. In this article, a commutative encryption and fingerprinting scheme is proposed to reduce the sender's loading. In this scheme, the TV program is firstly encrypted, then fingerprinted, and finally transferred. When compared with the traditional method, in the proposed method, only once encryption and N times of fingerprinting are required, which reduces the sender's loading greatly. Based on MPEG2 videos, a commutative encryption and fingerprinting scheme is presented, whose performances including security, efficiency, robustness, and imperceptibility are evaluated. Experimental results show that the scheme obtains good performances and is suitable for TV program distribution. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 227–235, 2009     

Ubiquitous WiFi and Acoustic Sensing: Principles,Technologies, and Applications

Journal of Computer Science and Technology - With the increasing pervasiveness of mobile devices such as smartphones, smart TVs, and wearables, smart sensing, transforming the physical world into...     

一种基于手机WiFi的无线测控技术及其应用

智能手机作为测控系统的移动监控终端具有良好的灵活性、便携性与便利性,WiFi通信由于其低成本高速率,运行环境兼容性高,成为一种比较实用的通信方式。该文构建了一个基于MSP430F149单片机的恒温控制应用场景,并将与智能手机的WiFi通信技术运用于该应用场景中,构成一个可通过移动终端远程监控的主从式测控系统。文中给出了系统的体系结构及硬软件设计方案,可为类似远程测控方案的实现提供借鉴。