教学课程资源库 更多>>

关键词： Proximal policy optimization (PPO)   RFID   RFID   task scheduling   task scheduling   data processing latency   data processing latency   data processing latency  

摘要： Radio Frequency Identification (RFID) technology has become integral in various industries for automating processes and tracking items in real-time. However, efficiently offloading the large volume of data generated by RFID tags to readers poses significant challenges, particularly in dynamic environments where static or rule-based offloading methods fall short. This paper presents a novel approach for dynamically offloading data using deep reinforcement learning, specifically employing the Proximal Policy Optimization (PPO) algorithm. The proposed method utilizes a central controller equipped with the PPO model to make intelligent, real-time reader selection decisions based on environmental factors such as reader load, tag mobility, and network conditions. The reward function is designed to minimize data processing latency while maintaining balanced reader utilization, resulting in enhanced system efficiency. Extensive experiments demonstrate that the proposed PPO-based strategy significantly reduces average data processing latency by 30% and improves reader load balancing by 16% compared to conventional scheduling methods compared to conventional scheduling methods.

关键词： Radio frequency identification (RFID)  

摘要： As the use of ultrahigh frequency (UHF) radio-frequency identification (RFID) increases in various fields requiring the rapid identification of a large number of tags, research has shifted toward improving the access capacity of RFID systems. This article proposes a frequency division multiple access (FDMA) extension of conventional time division multiple access (TDMA) RFID systems by modulating tag signals to different Miller-subcarrier frequencies, achieving a theoretical throughput limit value of 0.9135 average successfully read tags per slot, which is 2.48 times that of the usually referred dynamic frame-slotted Aloha algorithm. The power spectral density (PSD) of Miller-modulated subcarrier (MMS) sequences is derived to uncover the tag interference caused by the modulation signal sidelobe power within each subchannel. After that, a successive interference cancellation (SIC) scheme is employed in a four-tag signal reception situation, enhancing the simultaneous tag replies interference suppression and achieving a small performance deterioration if compared with a conventional TDMA system. An experimental analysis is also described to show the feasibility of the proposed FDMA extension of TDMA-based UHF RFID systems. © 2014 IEEE.

关键词： Encoding   Resonant frequency   Strain   Radiofrequency identification   Humidity   Varactors   Wireless sensor networks   Wireless communication   Digital control   Sensors   Humidity detection   radio frequency identification (RFID)   strain detection   structural health monitoring (SHM)   varactor diode   wireless digital control circuit  

摘要： This article proposes a multiparameter radio frequency identification (RFID) sensor with two controllable coding structures. The sensor integrates the ability of strain and humidity detection and is suitable for the field of structural health monitoring (SHM). The sensor is equipped with three S-shaped structures and one rectangular structure, two S-shaped structures are used as encoding units, one S-shaped structure is used as a humidity detection unit, and the rectangular structure is used as a strain unit. These structures are made on a Rogers RO3003 dielectric substrate. Controllable coding is achieved by changing the capacitance value of the varactor diode. A single coding unit can achieve a coding value of more than 2 bits. Compared with the traditional coding structure, the coding information capacity is improved, which is more suitable for distributed SHM scenarios that require multiple sensors. The digital control circuit is designed on the flexible printed circuit (FPC), which has the characteristics of bendability. It is mainly composed of a microcontroller, Bluetooth, varactor diodes, and other components, and can realize the wireless control function of the coding unit. A broadband antenna is further designed to match the working frequency band of the sensor. Experimental verification shows that the micro-strain of the strain unit is linearly related to its resonant frequency, and the humidity sensitivity is 193.92 kHz/%RH at a relative humidity (RH) of 33.7%-81.2%. The two encoding units can be controlled wirelessly to achieve 25-bit coding while having the advantages of small size and low cost. In the future, this method can be combined with self-powered devices and Internet of Things (IoT) gateways to achieve long-term state control of multiple sensors, providing a new method for SHM applications.

关键词： Radar shielding  

摘要： This paper presents a robust, high-capacity chipless encoding solution based on mapping resonance frequencies to Euclidean space. We introduce, for the first time, a methodology that exploits a usually undesired phenomenon, i.e., mutual coupling, as a method to improve the encoding capacity of chipless RFID tags. A deep analysis of the proposed method’s capability to mitigate fabrication tolerance and measurement uncertainties is performed. To address the computational challenges of the decoding phase, we employ machine learning to predict resonant frequencies of non-calibrated tags. A forecast accuracy of 100% without tolerance, and 97.6% with a tolerance of 50 MHz, is achieved using the trained model, which shows great potential to address concerns about simulation cost. A reliable space encoding efficiency of 22.5 bits/cm2 and spectrum encoding efficiency of 2.1 bits/GHz are achieved. As a proof of concept, we designed tags using periodically arranged, middle-notched planar dipole resonators, chosen for their fabrication-tolerant characteristics, enhanced Radar Cross Section (RCS) level and back-shielding properties. © 2014 IEEE.

关键词： Nanorods  

摘要： Wind speed detection plays a crucial role in agricultural production. For example, vegetation drones performing spraying operations are affected by wind speed, and strong winds may cause soil erosion and drought problems. Therefore, this paper attempts to investigate a low-cost, wind speed sensor for detection of wind speed in agricultural environments. The sensor is made of nanocomposite material consisting of ZnO, TiO2 and RGO, which uses nano friction between the nanomaterials to convert wind energy into electrical energy. The sensor receiving antenna was simulated and optimised by HFSS simulation software and the wind speed sensor was prepared by engraved printing technique. The morphology of ZnO/TiO2/RGO composites was observed by scanning electron microscopy. The combination of nanorod-shaped ZnO, nanorod-shaped TiO2 and flaky RGO has good electron migration ability and large surface area, which promotes the friction power generation of the material. In this paper, the amplitude change of the antenna centre resonance point of the wind speed sensor is about 10.7 dB under the wind speed change from 0 m/s to 10 m/s, and its sensitivity is 1.07 dB/m/s. The response time and the recovery time of the sensor are 0.8 s and 0.45 s, respectively. And it is proved experimentally that the wind speed sensor element can be reused. This research will bring more innovation and development opportunities for agricultural production. © 2001-2012 IEEE.

关键词： 双频无线通信技术   高压电缆   输电线路   运维管理   RFID  

摘要： 为提升高压电缆输电线路的运维效率与数据传输的稳定性，本文基于双频无线通信技术构建信息管理系统，结合动态频谱分配与空间耦合模式实现了多频段自适应传输。研究结果表明，该技术在复杂环境中有效保障了数据传输的连续性，提高了故障预警与状态监控的精确度。

关键词： Training   Wireless communication   Wireless sensor networks   Three-dimensional displays   Pose estimation   Transformers   Sensors   Synchronization   Radiofrequency identification   Synthetic data   3D pose augmentation and completion   conditional latent diffusion transformer   generative AI   multi-modal conditioning   RF sensing-based 3D human pose estimation  

摘要： Collecting paired Radio Frequency Identification (RFID) data and the corresponding 3D human pose data is challenging due to practical limitations, such as the discomfort of wearing numerous RFID tags and the inconvenience of synchronization between RFID and camera data. We propose a novel framework that leverages latent diffusion transformers to generate high-quality, diverse RFID sensing data across multiple classes. This synthetic data augments limited datasets by training a transformer-based kinematics predictor to estimate 3D poses with temporal smoothness. More important, we introduce a latent diffusion transformer training stage with cross-attention conditioning and an inference design of two-stage velocity alignment to accurately infer missing joints in skeletal poses, completing full 25-joint configurations from partial 12-joint inputs. This is the first method to detect >20 distinct skeletal joints using Generative-AI technologies for any wireless sensing-based continuous 3D human pose estimation (HPE) task. The application is particularly useful for RFID-based systems, which typically capture limited joint information due to RFID sensing constraints. Our approach can extend the applicability of wireless-based pose estimation to scenarios where collecting extensive paired datasets is impractical and achieving more fine-grained joint information is infeasible, such as pedestrian and health monitoring in occluded environments.

关键词： Resource allocation  

摘要： This paper investigates a non-orthogonal multiple access (NOMA)-enabled multi-user transmission system in a backscatter communication(BackCom) environment with integrated sensing and communication (ISAC). In this configuration, a base station (BS) simultaneously serves multiple users through a communication beam while utilizing a sensing beam to detect the presence of an radio frequency identification (RFID) tag. A joint beamforming design problem is formulated to maximize the sum-rate for the users while considering the constraints for successive interference cancellation (SIC) and the minimum quality of service (QoS) for all the communication users and the detection of the tag. Lagrangian dual transformation is used to address the non-convex nature of the objective function. Due to the coupling of variables, an alternating optimization (AO) based algorithm is proposed with guaranteed convergence. Through numerical simulations, we validate the efficacy of our proposed algorithm. Furthermore, we assess the impact of several key parameters on system performance, including the number of transmitting antennas at the BS, the available transmit power at the BS, the minimum QoS for the communication users, and the number of communication users. © 2012 IEEE.

关键词： Antennas   FCC   Impedance   Substrates   RFID tags   Tuning   Surface impedance   Resonant frequency   Patch antennas   Impedance matching   RFID tag   UHF   long range   multi-band   metallic object  

摘要： A compact flippable tag antenna of size ( 36 x 30 x 3.15 ) mm3 has been developed using double folded technique, for effective operation on metallic surfaces in ETSI/FCC bands. The antenna features a distinctive three-layered structure with serrations incorporated into the top, middle, and bottom layers. The top layer is connected to the bottom layer through inductive stub. The RFID chip connected between the bottom and middle layers. The tag is designed for dual band operation (ETSI and FCC) through the introduction of a flipping technique in combination with double-folded configuration used for effective impedance matching between the tag antenna and chip in both the bands. The tag works for ETSI band when the top layer act as a radiator while the bottom layer is attached to the metal plate. Further, when tag is flipped, it works for FCC band. In measurement scenarios, the fabricated tag achieves a maximum read range of 12.25 m in ETSI band and 9.9 m in FCC band when mounted on a metallic plate of size 20 x 20 cm(2). The proposed tag's performance is compared with already reported design through the evaluation of the figure of merit (FoM). With its dual band functionality and, metal-compatible design, the proposed tag eliminates the need for multiple tags or change in electronic product code (EPC) across intercontinental routes, making it highly suitable for tracking metal packages or containers in global logistics applications.

关键词： Radio frequency identification (RFID)  

摘要： This paper proposes the Dual-Response Collision Tree Anti-Collision Protocol (DRCT), redesigning tree-based approaches to address performance degradation in large-scale RFID identification. DRCT achieves optimization through a systemic design based on three key integrated mechanisms: Firstly, a novel Tag Grouping mechanism, fundamentally distinct from collision-bit-dependent methods, uses magnitude comparison against a reader-defined dynamic prefix (preStr). This eliminates the need to analyze the immediate collision for partitioning, enabling immediate parallel R0/R1-cycle processing readiness. Secondly, to effectively manage the identification process under this novel partitioning scheme, DRCT introduces a crucial Localized Search Control mechanism. This relies on tag-side counters (seDepth) which are conditionally updated by incrementing only when a tag is involved in an R1-cycle ( © 2014 IEEE.