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关键词： Strain measurement   RFID   Wireless sensors   Structural health monitoring  

摘要： The advancement of Radio-frequency identification (RFID) sensor technology presents a novel approach to monitoring the health of structures. However, the traditional RFID antenna sensor encounters issues with limited sensitivity and strain measurement capabilities in a single direction. In this investigation, we propose, model, analyze, and test an enhanced wireless and passive RFID strain sensor that offers improved sensitivity to strains and quantifiable measurements in orthogonal directions. Theoretical analysis based on multiphysics elastodynamics and electromagnetics illustrating the resonant response and distribution of current field density between two sets of orthogonally installed sensors under applied stress. Our findings reveal that the RFID strain sensor exhibits characteristics to electromagnetically induced transparency like (EIT-like) effect, enabling independent and intensified measurement of strains both horizontally and vertically. Experimental data demonstrates a linear correlation between the shift in resonant frequency of the sensor antenna and transverse strains as well as longitudinal strains, with sensitivity coefficients measuring -1.76 kHz mu epsilon- 1 for transverse strain and 2.17 kHz mu epsilon- 1 for longitudinal strain respectively. Consequently, by accurately analyzing variations in resonant frequency it becomes possible to deduce both magnitude and direction of strains on the antenna effectively laying groundwork for future engineering applications.

关键词： Sensors   Monitoring   Sensor phenomena and characterization   Antennas   Dipole antennas   Biomedical monitoring   Frequency measurement   Wearable sensors   Radiofrequency identification   Substrates   Antenna-based sensor (ABS)   battery-less   passive   radio frequency identification (RFID) sensor   sweat loss   sweat rate   wearable  

摘要： Emerging applications for wearable sweat loss measuring devices (SLMD) require real-time and long-term operation. These applications impose strict constraints to SLMD in terms of power consumption, size, and flexibility. Several efforts have been made to avoid battery limitations in electronic sensors. However, this remains an open challenge. This contribution presents a battery-less wireless data transfer device enabling sweat loss monitoring through a wearable, flexible, and low-profile antenna-based sensor (ABS). The proposed sensor design includes a small piece of fabric embedded in the antenna substrate to absorb sweat secreted by the skin in contact with the sensor inlet interface. This novel feature dramatically improves the frequency selectivity and frequency range of the ABS in response to the contact with liquids, which increases the measurement accuracy in comparison to the current state of the art, enabling real-time multilevel sweat loss detection. The sensor performance is assessed using a commercial radio frequency identification (RFID) system through laboratory and real-life experiments. The results show that the proposed sensor can track sweat loss within the typical range of the human perspiration rate (300-2100 g/m(2)/h) of healthy individuals using a battery-less and low-cost sensor.

关键词： Sensors   Radiofrequency identification   Coils   Curing   Capacitive sensors   Monitoring   Impedance   Dielectrics   Optical fiber sensors   Manufacturing   Curing monitoring   glass fiber reinforced polymer (GFRP)   interdigital capacitive (IDC) sensor   radio frequency identification (RFID)   time feature extraction  

摘要： In recent years, glass fiber reinforced polymers (GFRPs) have gained widespread adoption across various industrial sectors due to their advantageous properties. As a result, ensuring the production quality of GFRP components and enhancing manufacturing efficiency have become critical priorities to meet the growing demand and performance standards of fiber-reinforced composites. Wireless passive radio frequency identification (RFID) sensing technology has emerged as a valuable tool for monitoring the curing process of GFRP. However, the practical application of this technology is often hindered by the bulkiness of the devices and their susceptibility to interference, which limits their effectiveness in real-world scenarios. In this article, an low-frequency (LF) RFID capacitive sensor, which can be embedded in the GFRP, is proposed for monitoring GFRP curing. The sensor not only monitors subtle changes in electrical properties during the curing of GFRP but also integrates RFID technology for material tracking. This dual approach enhances the reliability of the curing process and ensures consistent high-quality production. The communication and sensing principles of the LF RFID capacitive sensor are described, and the feasibility of the method is analyzed using an equivalent circuit. A interdigital capacitive (IDC) sensor is printed on a flexible circuit board and connected to an RFID tag. The response of the LF RFID capacitive sensor during the curing process of the GFRP was investigated and compared with the measurement results of the dielectric analysis (DEA) method. The experimental results demonstrate the sensor's effectiveness in monitoring the curing process of GFRP, highlighting its potential for real-time assessment in composite manufacturing.

关键词： Resonators   Sensors   Internet of Things   Dielectric constant   Inductance   Semiconductor device measurement   Dielectric measurement   Chipless radio frequency identification (RFID)   dielectric constant   Internet of Things (IoT)   relative permittivity   sensory tag   Walabot  

摘要： Accurate dielectric constant measurements are crucial in Internet of Things (IoT) sensing applications to characterize materials and their properties. This article introduces an innovative capacitor-based chipless radio frequency identification (RFID) sensory array tailored specifically for precise measurements of dielectric constants in IoT contexts. The array incorporates Pi-shaped resonators and cylindrical capacitors, addressing challenges, such as low accuracy, limited $\varepsilon _{r}$ measuring range, and the reliance on bulky vector network analyzers (VNAs) as readers. Theoretical modeling, design considerations, sensor calibration, and validation processes are detailed, highlighting the array's precision and adaptability. Real-world IoT applications are demonstrated, showcasing the array's potential with a low-cost portable multiple-input-multiple-output (MIMO) reader, Walabot. This cost-effective solution overcomes conventional limitations, offering a versatile approach to dielectric constant measurements and opening up new possibilities for diverse IoT sensing applications. The integration of this sensory array with IoT technologies demonstrates the feasibility of smarter material characterization.

摘要： Nowadays attendance is vital in all educational institutes like the schools, colleges and universities, and collecting it is a very tedious job; moreover, the collected data is expected to be precise and accurate. The conventional method included taking attendance using a pen and paper which was inefficient and error prone. Hence an appropriate model should be selected in order to reduce errors. This paper presents attendance system enabled with RFID (Radio Frequency Identification) and smart phone application to collect the attendance. In this system only the teacher will have the RFID card which can be scanned on the system placed in the class. Subsequently a window will open for a short period of time within which all students will have to give their attendance using a mobile application. This can be done from their respective places without having to go to the scanner machine. Proposed system consists of RFID tag, an antenna that can scan the tag, a server and software components. It can be used in working places as well as educational institutes. The system provides real-time, accurate, and secure attendance records allowing administrators to manage attendance effortlessly, improve operational efficiency and can be stored in the form of an excel sheet. This data which will be stored can be further used to calculate percentages and proxy hence making the system efficient, user friendly and secure.

关键词： Frequency hopping  

摘要： Gesture tracking technology provides users with a "hands-free" interactive experience without the need to hold or touch devices. However, current gesture tracking research has primarily focused on tracking accuracy while neglecting issues of user privacy protection and security. This study aims to develop a gesture tracking system based on frequency-hopping RFID signals that effectively protects user privacy without compromising tracking efficiency and accuracy. By introducing frequency-hopping technology, we have designed a mechanism that prevents potential eavesdroppers from obtaining raw RFID signals, thereby enhancing the system’s privacy protection capabilities. The system architecture includes the collection of RFID signals, data processing, signal recovery, and gesture tracking. Experimental results show that our method significantly improves privacy protection levels while maintaining real-time and accuracy. This research not only provides a new perspective for the field of gesture tracking but also offers valuable insights for the use of RFID technology in privacy-sensitive applications. Copyright © 2024, The Authors. All rights reserved.

关键词： Radio frequency identification (RFID)  

摘要： Traveling through toll plazas is one of the primary causes of congestion, according to a recent study that examined these factors [29]. Electronic Toll Collection (ETC) can be set up to reduce the problem. This experiment focuses on improving the security of ETC by RFID tag, and number plate checking. For number plate checking image processing is used where CNN Classifier was implemented in order to detect vehicle registration numbers from the number plate. according to the registered number plate, mail will be sent to the respective owner for paying a toll fee within a certain amount of time to avoid a potential fine. While in this process toll fee will be automatically deducted in real-time from the owner's balance. People who would be waiting in queues to pay tolls would ultimately benefit from this system because no vehicles would slow down, saving them important time and inconvenience while traveling. Copyright © 2024, The Authors. All rights reserved.

关键词： 变电站机房   物联网   多功能水晶头   交换机端口   自动匹配  

摘要： 为了避免因为变电站机房内的交换机众多而造成故障难以排查的情况,本文基于物联网实现多功能水晶头与交换机端口自动匹配。选取RJ45水晶头调节电路模块,通过射频识别技术实现多功能水晶头和交换机端口的识别和定位,基于设备标识匹配、信号强度匹配以及网络拓扑结构匹配三种算法完成功能水晶头与交换机端口的自动匹配。实验发现,本文自动匹配算法下延长系数在1.0左右,设备识别准确率为94.37%,设备识别用时为37ms,且网络开销维持在4bit左右。本文算法下多功能水晶头与交换机端口自动匹配度程度最为理想,且设备识别率最高,网络开销小。

关键词： 一体式   仓位识别装置   无线通信技术   射频识别技术  

摘要： 设计开发了一种新型智能一体式无线仓位识别系统,通过结合RFID电子标签技术、LORA无线通信技术等多项关键技术,将油罐车仓位身份ID、该仓位需要装的油品、拟装该仓位的鹤管及装车系统进行数据对比,进行有效的安全识别连锁,避免装卸车过程中司机误插鹤管至错误仓位,导致油品混装、错装情况发生。该技术方案为石油、化工装车作业提供了全面的安全保障。

关键词： RFID   标签识别技术   高速公路   机电设备   监控系统  

摘要： 基于RFID标签识别技术,通过理论与实践相结合的研究方法,设计并实现了一套高速公路机电设备监控系统,目前该系统已在某省高速公路监控体系中得到应用。研究表明,该系统实现了对设备的远程监控与管理,显著提升交通安全水平,通过与设备关联的RFID标签,系统能够实时追踪设备状态及运行状况,迅速识别故障与异常,此外,该系统提高了设备管理的效率,集成了设备管理、数据记录以及报警等多项功能,方便了管理人员对设备的维护与管理。