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关键词： RFID   portable   phase   localization   optical  

摘要： In this paper a prototype method for manual inventorying and real-time 3D localization of RFID tagged products by a low-cost handheld UHF RFID reader is introduced. The device is equipped with a UHF RFID reader and an optical camera. "ArUco" markers with RFID tags are placed at known positions. Those optical and RF landmarks are used for the estimation of the pose of the handheld reader over time, by fusing the corresponding measurements in a Kalman filter. The reader also measures RFID tagged items at unknown locations. The positions of the tags are estimated by unwrapping the collected phase measurements, combined with the estimated antenna trajectory. Experimental results show that increased accuracy can be achieved by increasing the spatial density of the optical and RFID markers. The proposed method is expected to enhance low-cost manual inventorying, delivering 3D localization of the tagged products.

关键词： Construction equipment  

摘要： Construction equipment management system onsite significantly influences site productivity. There is a need to address the current issues faced by the practitioner and their needs for the management system so that proper strategies can be implemented. Hence, this paper aims to propose a framework of RFID-cloud construction equipment management system based on the current issues and user needs identified. This study conducted questionnaire survey and semi-structured interview with site staff to achieve the aim. The findings of current issues and site staff's needs reveal that the current strategy practiced on the site requires improvement, where RFID-based management system can be adopted. The concluded RFID-cloud system framework contributes to the construction industry by introducing how equipment management practice onsite can be transformed from a conventional method to a digital RFID-cloud system. © 2023 Elsevier Ltd. All rights reserved.

关键词： RFID技术   民航   行李运输  

摘要： 随着经济发展,社会不断进步,中国航空业也在不断发展,不管是客运需求,还是货物流需求,都在不断地增加。为进一步提高行李运输的效率和质量,在RFID技术的基础上,人们已经对民航行李的运输方案进行了深入的探索。在这一过程中,最为关键的一个步骤就是运用RFID技术,对行李进行识别分类,并提供行李的定位追踪,从而降低行李的混淆和损失,使行李的运输更加安全,给乘客带来更大的便利。因此,将RFID技术应用在民航行李运输中具有重要价值。本文对RFID技术在民航行李运输中的应用进行了探究,希望能够为相关人士带来一些帮助。

关键词： Cybersecurity   electrochemical sensors   fast health interoperability resources   healthcare Internet of Things systems   Near Field Communication   radiofrequency identification  

摘要： Points-of-care (PoCs) augment healthcare systems by performing care whenever needed and are becoming increasingly crucial for the well-being of the worldwide population. Personalized medicine, chronic illness management, and cost reduction can be achieved thanks to the widespread adoption of PoCs. Significant incentives for PoCs deployment are nowadays given by wearable devices and, in particular, by RFID (RadioFrequency IDentification) and NFC (Near Field Communication), which are rising among the technological cornerstones of the healthcare Internet of Things (H-IoT). To fully exploit recent technological advancements, this paper proposes a system architecture for RFID- and NFC-based PoCs. The architecture comprises in a unitary framework both interfaces to benefit from their complementary features, and gathered data are shared with medical experts through secure and user-friendly interfaces that implement the Fast Health Interoperability Resource (FHIR) emerging healthcare standard. The selection of the optimal UHF and NFC components is discussed concerning the employable sensing techniques. The secure transmission of sensitive medical data is addressed by developing a user-friendly "PoC App" that is the first Web app exploiting attribute-based encryption (ABE). An application example of the system for monitoring the pH and cortisol levels in sweat is implemented and preliminarily tested by a healthy volunteer.

关键词： Authentication chain   integrity authentication   missing tag detection   RFID  

摘要： Major manufacturers and retailers are increasingly using RFID systems in supply-chain scenarios, where theft of goods during transport typically causes significant economic losses. This paper studies how to achieve time-efficient and secure integrity authentication solutions for RFID systems. We start with a straightforward solution called SecAuth, which uses a secure identity stored on reserved memory to securely authenticate the tags. We then propose a time efficient KTAuth protocol, which designs a verification chain mechanism to efficiently authenticate a large set of tags based on a small set of pre-defined key tags. We point out that the limitation of KTAuth is that it takes too much overhead to write a large block of data to tag memory, which leads to the proposed group selection mechanism. The KTAuth with group selection (KTAuth-GS) could select key tags with a single select command, which helps to quickly identify the key tags and reduces the data writes on them. Experiments and simulation results demonstrate that the proposed KTAuth-GS can defend against counterfeiting attacks by providing more reliable results and reducing the execution time by as much as a factor of 5 when compared with a baseline tag identification protocol.

关键词： Antenna measurements   Classification tree analysis   Radiofrequency identification   Sensors   Radio frequency   Hidden Markov models   Antennas   Contactless sensing   material identification   moving radio frequency identification (RFID)   received signal strength (RSS)   UHF RFID  

摘要： Radio frequency identification (RFID)-based sensing technology has recently gained extensive attention in numerous applications. However, contactless sensing still faces significant challenges. The existing works are generally limited by backscattered signals of phase and the received signal strength (RSS) as an intuitive combination of feature parameters. In this article, DIMAR, an algorithm leveraging moving tag is presented to enable contactless identification of dielectric materials by determining the dielectric constant using a UHF RFID system. In this framework, by blocking the line-of-sight (LOS) link between the reader and tag, we present a theoretical analysis of the influence of material reflection on RSS from the perspective of electric fields. Then the feature model of a cost function is proposed with respect to the reflection coefficient and the complex permittivity, i.e., the relative permittivity and conductivity. Covariance matrix adaptation evolution strategy (CMA-ES) is introduced to solve the mathematical model, and density-based spatial clustering of applications with noise (DBSCAN) algorithm is used for noise reduction to deal with environmental distractions. Furthermore, due to the nonconvexity of the model, we provide a geometric analysis for the convergence verification within the domain range, and further a numerical analysis to verify rationality and convergence of CMA-ES. Experiment and simulation results show that DIMAR performs superiorly in identification accuracy even in multipath environments. And since the measured materials have close proximity of the properties, DIMAR can achieve fine-grained identification resolution.

关键词： 射频识别   应变   腐蚀   天线   结构健康监测  

摘要： 作为国家重要的基础设施,管道承担着石油、天然气等能源资源的运输任务。然而,由于管壁受流体冲刷、电化学及微生物作用等多种因素的影响,极易发生腐蚀现象。腐蚀区域会在内部介质压力作用下产生应力,降低管道的抗疲劳强度。一旦引发管道泄漏失效,将导致严重的环境污染和安全生产事故。因此,管道结构健康监测(Structural Health Monitoring,SHM)技术的使用变得至关重要。将射频识别(Radio Frequency Identification,RFID)技术与传感技术相融合设计出大量无源、无线、微型、免维护的传感标签安装在管道上用于整体或局部健康监测,是确保管道安全的一种可靠、有效和经济的潜在解决方案。本文针对管道无损检测领域关注度最高的应力应变和缺陷腐蚀问题,开展用于管道结构健康监测的射频识别传感技术研究。应力的检测通常采用矩形RFID应变传感标签完成。处于复杂应力条件下的管道,只有结合应变幅值和方向才能准确评估其应力状态。然而,现有的矩形RFID应变传感标签只能够检测沿矩形辐射元件长度或宽度方向的应变幅值,即标签天线应变传感器主要应用在平行于矩形辐射元件边缘的应变。当矩形辐射元件与被测应变存在夹角时,测量数据与实际应变之间存在较大误差。为了实现应变幅值和方向的检测,本文提出了一种基于RFID传感标签阵列的应变幅值及方向检测方法:首先基于单个标签天线应变传感的机理,提出了由4个相互夹角为45°的传感标签组成的阵列以实现应变幅值和方向的定量检测;之后设计了工作在超高频的抗金属、小型化应变传感标签;并借助于高频电磁场和力学耦合仿真模型,对该RFID标签天线作为应变传感器的性能进行了分析,以谐振频率偏移量作为应变检测的特征参数,该传感标签在电气长度方向和宽度方向具有不同的应变灵敏度,能够满足阵列传感的要求;最后对应变传感标签及其阵列进行了拉伸试验,验证了其应变幅值和方向检测性能。结果表明,单个传感标签在长度方向和宽度方向的应变灵敏度分别为-873.91 Hz/με和57.28Hz/με;设计的传感标签阵列的应变幅值检测精度在10%以内,应变方向检测误差在3°以内。由于趋肤效应的存在,现有RFID传感系统中的电磁波无法有效穿透趋肤层进行内部腐蚀的感知。为了实现内部腐蚀监测,本文提出了一种基于磁导率扰动的RFID内壁腐蚀检测方法:首先从频域形式的麦克斯韦方程出发,研究了RFID传感标签和趋肤层内磁导率扰动的耦合机制;受此启发,在RFID传感系统引入偏置磁场,探究了内部腐蚀造成的磁场畸变和趋肤层内磁导率扰动规律,突破了“内部腐蚀-表层磁导率”的空间限制;然后设计了对磁导率敏感的RFID传感标签,并对其传感特性进行了研究;最后开展金属结构内壁腐蚀检测实验,验证了“内部腐蚀-磁导率扰动-射频响应”的传感特征转化关系;结果表明,不同深度的内部腐蚀引起的表面磁导率扰动会产生不同的谐振频率偏移量。因此,基于磁导率扰动的RFID方法为应用RFID传感技术进行管道内壁腐蚀监测提供了一种可行方案。基于RFID传感标签阵列的应变幅值和方向检测方法,以及基于磁导率扰动的RFID管道内壁腐蚀检测方法的提出,有助于推动RFID传感系统在管道结构健康监测领域的应用,保障管道安全有效运行。

关键词： Head kinematics   head tracking   radiolocation   RFID   wearable sensors  

摘要： This paper describes an RFID system for head orientation tracking (R-SHOT), a novel wireless and battery-free approach for monitoring head kinematics. R-SHOT uses two linear polarized antennas mounted on a metal frame backpack, three commercial RFID tags placed orthogonally on the subject's head, an RFID reader, software for data collection and processing, and an IMU for calibration. Training datasets were collected using stationary head positions with varying yaw, pitch, and roll, which were then used to develop a second-order multi-variate model to predict the Euler angles (R-2 = 0.997 and standard error = 1-3 degrees). Attempts to use a first-order model, reduce variables, and increase the number of static head positions for model training did not yield favorable results. Challenges in model development due to noise and asynchronous sampling were overcome using a Kalman filter and linear interpolation. The R-SHOT model developed using static head positions was found to predict Euler angles - when applied to full head motion - with low error, especially when the head position was closer to an extreme. The development of this model holds the keys to future real-time application of R-SHOT for patient care and mobility aid solutions.

关键词： Digital twin   RFID   logistics   case study   automotive industry  

摘要： RFID is used in logistics in the automotive industry to automate processes and optimise material flow. However, the data generated by RFID installations during operation offer more potential for further analyses to collect even more benefits from the technology. Therefore, in this paper, RFID data will be used to create a digital twin of the RFID-enabled material flow (DTRMF) in real-time and to programme various big data analyses. The architecture of the DTRMF must meet various qualitative requirements. Since the big data and digital twin architectures available in the literature either do not optimally fulfil all these requirements, or they are not described in enough detail to support real applications, this paper presents a new digital twin architecture for RFID-enabled material flow. This architecture consists of the data ingestion layer, data processing and analyses layer, data storage layer, visualisation layer, and the optional semantic layer. In addition, suitable technologies for the implementation of the architecture are described, and the feasibility of the architecture is demonstrated and verified by means of a case study.

关键词： FPGA   射频识别系统   中继天线   远距离通信   ISO/IEC15693  

摘要： 近年来,国家不断加大对物联网技术发展的支持力度,无线射频识别(Radio Frequency Identification,简称RFID)作为物联网核心技术之一,得到快速发展并拓展了新的应用领域。RFID技术基于电感或电磁耦合方式实现非接触式读写,凭借高效性、自动化和多目标快速识别等优势,广泛应用于物品识别、数据采集、物流管理等领域。RFID系统的数据交换是通过依赖于天线耦合而实现的无线电磁波传输进行的。然而,电磁波在空间传输过程中存在信号衰减、路径损耗等现象,特别是超高频RFID系统在识别金属材料介质时会导致多径传播和信号干扰,遇到水介质时容易出现衰减和解耦,严重影响RFID系统的读写通信距离,降低了RFID系统的识别有效性和可靠性。本文围绕RFID系统如何实现远距离读写通信展开研究,重点对阅读器软硬件设计、中继天线等方面进行了研究,设计了一套工作频率为13.56MHz的高频RFID系统。首先,根据RFID系统特性和ISO/IEC15693标准,确定高频RFID系统结构和工作机制。采用“现场可编程逻辑门阵列(FPGA)+收发电路”方案实现RFID系统的基带信号产生与接收信号处理。重点介绍了RFID通信协议中幅度调制技术(ASK)、脉冲位置编码调制、数据帧结构、循环冗余校验(CRC)以及基于时分多址(TDMA)的防碰撞处理技术。其次,引入了中继天线设计。建立无中继天线的双天线耦合系统和有一个中继天线的三天线耦合系统,理论推导影响天线耦合系统传输效率的因素。通过先进设计系统(ADS)软件建立等效电路图分析传输损耗S21参数,天线均在频率为13.56MHz下谐振,对比分析两种天线耦合系统的传输效率和传输损耗。仿真数据表明:在RFID系统中引入中继天线可以有效降低传输损耗,提高无线电磁波传输效率。然后,基于无线电电路设计思路,设计了高频RFID阅读器硬件电路,包括数字基带电路、射频发射电路、天线切换电路、超外差接收机电路以及电源电路。并确定了逻辑控制、数据处理、传输协议的实现方式,在FPGA芯片上编写相应的Verilog代码,通过Model Sim仿真工具进行时序仿真验证,模拟数据传输过程。最后,搭建RFID系统测试环境,对阅读器的数字基带电路、射频发射电路和接收机电路的各个关键位置的信号进行测试,验证硬件平台和软件设计的正确性。建立RFID测试系统进行定量和定性分析,研究了中继天线对接收天线电压和标签最远读写距离的影响。实验表明:在RFID系统中引入中继天线设计,有效降低了传输损耗,提高了无线电磁波强度和传输效率,实现RFID系统更远距离读写通信,达到了预期效果。