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关键词： Coils   Implants   Couplings   Wires   Shape   Inductive coupling   Finite element analysis   Near Field Resonant Inductive coupling   RFID   orthopedic implants   knee  

摘要： Our research aims to enhance smart orthopedic knee implants used in Total Knee Arthroplasty (TKA). With the projected quadrupling of TKA demand by 2030 due to factors like aging populations, rising obesity rates, and broader indications for younger patients, our focus is on instrumented medical implants to measure knee parameters. In this paper, we report the optimization of a wireless power transmission system for powering smart knee implants, employing an established HF Near-field Resonant Inductive Coupling (NRIC) technique at 13.56MHz inside the stem of a tibial knee implant. We propose a pragmatic optimization approach in this study, guided by the integration constraints of a knee implant and validated by orthopedic surgeons through cadaveric specimen testing. Finite Element simulations guided the selection of a frontal 3-turn solenoid (called "paperclip" coil) at the Rx side, located at the tip of the stem, which demonstrated balanced performance metrics and reasonable volume occupancy (1.6 cm(3)). Power transfer measurements were conducted through conductive solutions mimicking skin, muscle, and bones. At 13.56MHz , a power transfer efficiency eta of 30% and 7.5% ( 300mW and 75mW at 1W input power) was achieved at Tx-Rx distances of 25mm and 40mm respectively. The proposed solution was implanted in a cadaveric specimen : 250mW was obtained at an estimated 30mm distance for an input power of 1W at the Tx side. For the same distance, we also performed a successful DC power provision up to 64mW at 3V DC and data transfer functions at 26kbits(-1) in the cadaver. The proposed system, with its integration strategy, holds promise in powering advanced sensor functions, contributing to the identification and monitoring of postoperative complications and potentially reducing the need for long-term revisions.

关键词： Radio frequency identification   Construction projects   Project performance   Sustainability  

摘要： PurposeTo realize full benefits without sacrificing the practicality of such projects, the decision-making process for residential building construction needs to include sustainability principles at every level. Therefore, this paper aims to investigate the applicability of radio frequency identification (RFID) and identify the barriers that impede its successful adoption in construction projects to achieve sustainability. Design/methodology/approachThis paper opted for a quantitative approach by using a structured questionnaire survey. A total of 107 responses were collected from Nigerian construction practitioners involved in private and public construction businesses. FindingsThe results showed the high cost of RFID implementation, with a mean score of 4.42 as the top-ranked barrier, followed by lack of security, maintenance, power availability and inadequate training. This study further deployed Ginni's mean difference measure of dispersion and revealed that the stationary barrier to adopting RFID technology is the lack of demand. Practical implicationsThe findings of this research can assist decision-makers in improving the sustainability of all building projects by implementing RFID. Originality/valueThe findings of this study will serve as the basis for comprehension and critically evaluate the numerous barriers preventing the widespread adoption of RFID technology.

关键词： RFID   Metal crack detection   Crack sensor   Radar cross-section  

摘要： PurposePassive chipless RFID (radio frequency identification) sensors, devoid of batteries or wires for data transmission to a signal reader, demonstrate stability in severe conditions. Consequently, employing these sensors for metal crack detection ensures ease of deployment, longevity and reusability. This study aims to introduce a chipless RFID sensor design tailored for detecting metal cracks, emphasizing tag reusability and prolonged service ***/methodology/approachThe passive RFID sensor is affixed to the surface of the aluminum plate under examination, positioned over the metal cracks. These cracks alter the electrical length of the sensor, thereby influencing its amplitude-frequency characteristics. Hence, the amplitude-frequency profile generated by various metal cracks can effectively ascertain the occurrence and orientation of the *** and experimental results show that the proposed crack sensing tag produces different frequency amplitude changes for four directions of cracks and can recognize the crack direction. The sensor has a small size and simple structure, which makes it easy to ***/valueThis research aims to deploy crack detection on metallic surfaces using passive chipless RFID sensors, analyze the amplitude-frequency characteristics of crack formation and distinguish cracks of varying widths and orientations. The designed sensor boasts a straightforward structural design, facilitating ease of deployment, and offers a degree of reusability.

关键词： CNN-LSTM   RFID   Microgrid Stability   Rotor angle stability   And modified Galerkin Method  

摘要： The article proposes a novel approach to assess rotor angle stability in microgrids by enhancing the Modified Galerkin Method (MGM), which is based on the Polynomial Approximation, using real-time RFID data acquisition. Due to their reliance on assumptions, traditional rotor angle stability methodologies frequently fail in online transient stability testing. MGM successfully captures the dynamic behavior of microgrids by approximating state variables using a sequence of polynomials and coefficients. Redundant data, like as vibrations or noise signals, can cause delays in defect diagnosis and decrease diagnostic accuracy. This problem is addressed by integrating RFID technology. RFID technology could potentially be used with a hybrid CNN-LSTM model to develop a sophisticated fault diagnostic system. This entails identifying fault characteristics through the use of signal processing techniques and feature extraction methods, such as the Fourier transform and time-domain statistical features. In addition, we use Total Harmonic Distortion (THD) to reduce superfluous data. The suggested techniques significantly increase fault detection efficiency and precision, outperforming existing techniques with a 0.94 classification accuracy. An extensive case study on an IEEE 3-machine 9-bus system is used to illustrate its efficacy, showing observable improvements in fault detection speed and accuracy that make microgrid operations safer and more dependable.

关键词： Sensors   Antennas   Radiofrequency identification   Surface cracks   Sensor phenomena and characterization   Sensitivity   Surface impedance   Antenna sensor   crack detection   radio frequency identification (RFID)   structural health monitoring (SHM)   surface crack  

摘要： Wireless monitoring of cracks is a critical task in evaluating the state of metal structure. Radio frequency identification (RFID) antenna sensors have been intensively investigated for crack detection. Nevertheless, the development of RFID antenna sensors satisfying the requirements of high sensitivity and coverage remains a challenge. In this article, an ultrahigh frequency (UHF) RFID antenna sensor with coupled ring resonators has been proposed, where the outer ring is designed for radiation and sensing, and the inner ring is utilized for impedance matching. The sensor is directly placed on metallic surface, forming an electromagnetically induced transparency-like (EIT-like) effect to enhance sensing capabilities. Due to a relatively uniform electromagnetic field constrained under the outer ring, surface cracks can be detected in different positions and directions. The sensor is sensitive to both depth and width of crack, with a sensitivity of -5.46 MHz/mm in crack depth and -10 MHz/mm in crack width detection. According to the results of this investigation, a potential sensing technique for practical applications is demonstrated.

关键词： AR/VR   CPS   IoT   machine learning   neural networks   radar   RFID  

摘要： With the emerging developments in millimeter-wave/5G technologies, the potential for wireless Internet of things devices to achieve widespread sensing, precise localization, and high data-rate communication systems becomes increasingly viable. The surge in interest surrounding virtual reality (VR) and augmented reality (AR) technologies is attributed to the vast array of applications they enable, ranging from surgical training to motion capture and daily interactions in VR spaces. To further elevate the user experience, and real-time and accurate orientation detection of the user, the authors proposes the utilization of a frequency- modulated continuous-wave (FMCW) radar system coupled with an ultra-low-power, sticker- like millimeter-wave identification (mmID). The mmID features four backscattering elements, multiplexed in amplitude, frequency, and spatial domains. This design utilizes the training of a supervised learning classification convolutional neural network, enabling accurate realtime three-axis orientation detection of the user. The proposed orientation detection system exhibits exceptional performance, achieving a noteworthy accuracy of 90.58% over three axes at a distance of 8 m. This high accuracy underscores the precision of the orientation detection system, particularly tailored for medium-range VR/AR applications. The integration of the FMCW-based mmID system with machine learning proves to be a promising advancement, contributing to the seamless and immersive interaction within virtual and augmented environments.

关键词： circular polarization   metamaterial absorber   MIMO antenna   RFID  

摘要： This communication designs and investigates a twin-port microstrip antenna loaded with a metasurface (MS). The proposed MS works in two ways: (i) artificial ground plane for radiator and (ii) as an ideal absorber of normal incoming waves at the same time. A stair shaped slot is loaded on rectangular patch for creating circularly polarized wave in between 835-894 MHz. Antenna port slots oriented in a mirror manner increase isolation by 25 dB. To act as a validation tool, the suggested antenna was built and its executions in individually operating modes evaluated by statistical and experimental analysis. It is shown that combining the patch and absorber results in a well-matched antenna in between 710-980 MHz with improved gain (more than 3.0 dBi). The proposed antenna design effectively used for UHF (Ultra High Frequency) radio-frequency identification (RFID) applications, which is due to its ability to mitigate multipath reflection issues and incorrect RFID reading.

关键词： Collection management   RFID   GIS   LANDMARC  

摘要： In recent years, the integration of Radio Frequency Identification (RFID) technology with deep learning has revolutionized the Internet of Things (IoT), leading to significant advancements in object identification, management, and control. Museums, which rely heavily on the meticulous management of collections, require precise and efficient systems to monitor and oversee their valuable assets. Traditional methods for tracking and managing museum collections often fall short in providing real-time updates and ensuring optimal environmental conditions for preservation. These shortcomings place a considerable burden on museum staff, who must manually track, inspect, and maintain extensive collections. This study addresses these challenges by proposing an advanced electronic management system that leverages the synergy between RFID technology and Geographical Information Systems (GIS). By integrating an enhanced LANDMARC algorithm into our geoinformation framework, the system visually represents the real-time location of museum collections on custom electronic maps, significantly improving the accuracy and timeliness of environmental monitoring. Additionally, RFID technology is utilized to continuously identify the real-time location of museum staff, facilitating the evaluation of their inspection tasks. This dual approach not only enhances the operational efficiency of collection management but also supports the development of intelligent, automated systems for museums, advancing the application of RFID technology in item identification and location management.