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关键词： Seeds (agriculture)   Location awareness   Three-dimensional printing   Received signal strength indicator   Passive RFID tags   Insects   Temperature measurement   Sensors   Pathogens   Mechatronics   Localization   passive radio frequency identification (RFID)   small-scale fliers   wind-dispersal  

摘要： The concept of sensing environmental parameters in the air has recently gained attention through drone-based, insect-based, or wind-dispersal-based mechanisms. Interestingly, wind-dispersal mechanisms require no driving mechanical system and are solely powered by wind energy to scan and sense selected areas of interest. In this paper, we propose a low-cost system of wind-dispersal fliers that are coded and localized based on passive UHF RFID technology. For the flier's mechanical design, a 2D structure is first designed, inspired by winged seeds, consisting of four wings with asymmetrical cross-sections to provide better mechanical stability during descent and enhanced integration with UHF RFID tags. The 2D structure is then transformed into 3D configurations by tilting the blades at different angles and utilizing different curvatures. By introducing porosity in the 3D design and optimizing the blades' angles and curvature, a low terminal velocity of 1.64 m/s is achieved based on measurements. The fliers are fabricated using Laser Sintering from Polyamide 12 (PA12) with a low thickness of 200 mu m. For system demonstration, four distributed reader antennas are employed to interrogate a coded flier equipped with a passive RFID tag that uses a UHF Gen2 chip. For system evaluation, various scenarios encompassing distinct tags and flier trajectories are evaluated using a Received Signal Strength Indicator (RSSI) algorithm, specifically tailored to meet our system requirements. The average localization error varies across the evaluated scenarios, providing insights into the performance of the system under different conditions.

关键词： Sensor systems   capacitive pressure sensor (CPS)   capacitive pressure sensor (CPS)   polydimethylsiloxane (PDMS)   polydimethylsiloxane (PDMS)   radio frequency identification (RFID) sensor   radio frequency identification (RFID) sensor   vital sign monitoring   vital sign monitoring  

摘要： Novel sensing and communication techniques have created new opportunities for unobtrusive vital sign monitoring. Due to the features of wireless power and data transfer and non-line-of-sight interrogation of radio frequency identification (RFID), its innovative integration with different sensing elements has become a promising solution. Since the heartbeat and respiration signals are weak and their measurement is time-consuming, a lightweight and flexible solution for their unobtrusive wearable sensing remains a challenge. This investigation presents a novel capacitive pressure sensor (CPS)-augmented RFID solution for simultaneous and wearable sensing of heartbeat and respiration. The main contributions include: first, proposal of an innovative RFID-based vital sign monitoring scheme, which integrates a CPS for heartbeat sensing and employs RFID phase signals for respiration sensing;second, design and fabrication of a polydimethylsiloxane (PDMS)-based flexible and porous slotted CPS for continuous heartbeat sensing;and third, development of respiration signal reconstruction algorithm using the weak and noisy RFID phase integrating phase disambiguation, denoising, baseline removal, and peak detection. Experimental studies are conducted to verify the feasibility and effectiveness of the presented techniques.

摘要： Radiofrequency identification (RFID) empowers numerous modern applications, enabling efficient accurate tracking and management of products, assets, and individuals in retail, logistics, and access control. Considering those and other perspective applications, there is a need to reduce the overall footprint of a passive tag while maintaining its reading range on at least a meter scale. Employing dielectric resonant antennas as a core of RFID tag design presents an appealing strategy, as it facilitates size minimization while counterbalancing this reduction by increasing the refractive index. Here we investigate the fundamental and practical constraints of this type of miniaturization, primarily focusing on the bandwidth limitations and temperature stabilities associated with high-index ceramic elements. Specifically, tags with relative dielectric permittivities ranging from 100 to 1250 were explored, demonstrating that a permittivity of 500 is optimal for footprint miniaturization and temperature monitoring, with a sensitivity of 3 MHz/degrees C. In contrast, a permittivity of 100 is ideal for thermostable tags. Further size reduction using permittivities above 500 decreases the communication channel bandwidth below the thresholds required by standard UHF RFID protocols, which thus serves as a practical limitation for further footprint reduction. RFID tags with cubic millimeter-scale footprints, capable of being accessed from distances well over a meter, and ideally integrated with sensor functionalities, have the potential to revolutionize the Internet of Small Things where compact and resource-limited items can become active participants in a global network.

关键词： IoT   RFID   medication   logistics   real-time monitoring   cold chain  

摘要： In general, managing the cold chain of diabetes medication involves considerable issues nowadays, particularly regarding real-time monitoring of those logistic chains. The safety and efficacy of diabetes medication is often compromised during transportation due to inadequate real-time tracking methods. This project uses smart technology based on the Internet of Things (IoT) and cloud databases management to develop an improved real-time monitoring system in order to enhance the cold chain logistics process. Using special packaging with Radio-Frequency Identification (RFID) tags and installing sensors and introducing the Global Positioning System (GPS) modules on trucks to monitor and analyse temperature, humidity, and location, all of these parameters are crucial for preserving product integrity, and those key metrics are the primary elements of the recommended approach. The data collected provides valuable insights, enabling spoilage reduction, improving operational efficiency, and contributing to sustainability in the pharmaceutical supply chain. By following the guidelines set by the Saudi Food and Drug Authority, this project aims to ensure the safety and efficiency of insulin products throughout their journey.

关键词： 节点地震仪   综合平台软件   低功耗蓝牙   超高频射频识别   系统软件集成  

摘要： 针对无线节点地震仪物探与地震监测过程中实时交互能力不足、功能匮乏的现状，设计基于Android的节点地震仪监控与野外布设综合平台。平台采用低功耗蓝牙（bluetooth low energy, BLE）通讯技术，通过自定义加密无线通讯协议实现移动终端与节点式仪器的数据通讯与设备控制，完成对单点设备的单/三分量地震动速度信号实时显示、状态查询与单台/多台同步设置；并应用超高频射频识别技术、QR扫描和电子地图实现野外快速布设节点地震仪阵列测线；应用SQLite数据库和本地文件系统实现测线可靠记录、参数设置和系统日志的管理。经测试，平台对提高节点地震仪器系统野外物探勘测或流动监测工作效率有较大提升，较好解决了无线节点地震仪器无法现场修改内部参数的弊端，界面友好，能够满足实际野外作业需求。

关键词： 节点地震仪   RFID测距   一维卷积神经网络   超参数优化   非支配排序遗传算法   多目标优化  

摘要： 针对无线型节点地震仪在野外复杂勘探环境下无法准确定位和可能丢失的问题，研究超高频RFID高精度测距定位具有重要意义。首先利用接收信号强度指示器（RSSI）近似计算公式筛除误差较大的采样值；然后设计第3代非支配排序遗传算法（NSGA-Ⅲ）的2个优化目标函数，其自变量统一为学习率下降因子、初始学习率、批大小等一维卷积神经网络（1D-CNN）超参数，因变量分别为网络预测结果与理论值的决定系数(R2)和平均偏差误差（MBE）；最后以最佳超参数值构成NSGAⅢ-1D-CNN新模型，以提高RFID测距模型的稳定性和精确度。实验结果表明，新模型在100轮循环实验下的节点地震仪RFID测距误差较小，在R2、均方根误差（RMSE）、平均绝对误差（MAE）、MBE等多个指标上均表现优异，均值分别为0.977 9、0.058 6、0.047 2、—0.001 3，相对于其他模型具有更高的测距定位精度，在野外物探中具有一定应用价值。

摘要： Low-cost and passive identification systems are necessary for real time IoT (internet of things) monitoring. The paper presents a novel designed chipless RFID tag towards read range enhancement of (2.70 mm). A novel approach of array-based resonators towards real time read range enhancement is proposed in this research work with efficient performance. A mould-based solution casting technique is used for chipless tag fabrication. Multi-Walled Carbon Nanotubes (MWCNTs) are used as electrodes with flexible Polydimethylsiloxane (PDMS) substrate. The developed battery-free tag can encode 3-bits data while staying in compact dimensions of 20 x 20mm2. The single unit tag is extended to 3 x 3-array structure. The novel approach leads the tag towards RCS increment of 25.17dBsm. The tag has been extended to 5 x 5-array for Poly-ethylene terephthalate (PET) substrate with silver nanoparticle-based ink radiator leading to RCS increment of 25.16dBsm. The tags read range performance is very highly reliable and stable as measured from multiple samples and is suitable for deployment in a smart sensing and IoT identification network.

关键词： RFID   laser-induced graphene   RFIDtex tag   RFIDLIG transponder   laser   smart textiles   graphene antenna   UHF band   impedance matching  

摘要： The aim of the research is to investigate the impact of laser operation parameters on the LIG (laser-induced graphene) process. It focuses on evaluating the feasibility of using the induced conductive layers to create antenna circuits that are dedicated to radio-frequency identification (RFID) technology. Given the specific design of textile RFIDtex transponders, applying the LIG technique to fabricate antenna modules on a flexible substrate (e.g., Kapton) opens new possibilities for integrating RFID labels with modern materials and products. The paper analyses the efficiency of energy and data transmission in the proposed innovative UHF RFIDLIG tags. The signal strength, read range, and effectiveness are estimated in the experimental setup, providing key insights into the performance of the devices. Based on the obtained results, it can be concluded that changes in laser cutting parameters, the size of the induced graphene layer, and the method of fixing the Kapton substrate significantly affect the quality of the cutting/engraving components and the conductivity of burned paths. However, these changes do not directly affect the correct operation of the RFIDLIG transponders, owing to the fact that these structures are resistant to external impacts. Nevertheless, an increased range of data readout from the RFIDLIG tags can be achieved by using graphene paths with higher conductivity. The obtained results confirm the validity of the proposed concept and provide a foundation for further research on adapting the LIG method to automated logistics, ultimately leading to the development of more versatile and innovative solutions for identification processes.

关键词： Reconfigurable intelligent surfaces   Antennas   Wireless fidelity   Wireless communication   Surface waves   Antenna feeds   Switches   RFID tags   Delay lines   Decentralized control   Distributed control   reconfigurable intelligent surface (RIS)   radio frequency identification (RFID)   smart reflect array unit cell   smart wall   SP4T switch   throughput (TP)   Wi-Fi   wireless extension  

摘要： This article proposes a scalable reconfigurable intelligent surface (RIS) that utilizes distributed wireless control for 2.4 GHz Wi-Fi systems, rather than centralized control, enabling it to scale to arbitrarily large surfaces. The RIS is composed of tiles, each containing 4 x 4 unit cells. To control the RIS elements in each tile, we integrated a single radio frequency identification (RFID) antenna operating at a center frequency of 915 MHz. The RIS elements in each tile are connected to distinct delay lines using a single-pole four-throw (SP4T) RF switch configuration. This configuration allows phase manipulation of the reflected wave at 0(degrees), 90(degrees), 180(degrees), and 270(degrees) round-trip phase shifts for each element. With this distributed control scheme, we achieve an ultralow-power, scalable RIS architecture that offers enhanced flexibility and adaptability. For verification, the bistatic radar cross section (RCS) of an 8 x 8-element is measured and compared with the simulation results, showing good agreement between the simulation and measurement. Furthermore, a 16 x 16-element RIS prototype, with a total size of 1 x 1 m, is fabricated, and an experimental setup for realistic throughput (TP) measurement in typical office space and laboratory for both line of sight (LOS) and non-line of sight (NLOS) between receiver access point (AP) and transmitter AP using an actual Wi-Fi AP for different modulation coding scheme (MCS) index is measured and compared. The dc power required for the control board, RFID chip, and to reconfigure the SP4T switches of each tile is approximately 21 mu W, supplied by a 3 V battery.