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关键词： Planar microstrip   UWB antenna   chipless RFID   realized gain   total efficiency  

摘要： In this article, a new small size planar microstrip tree profile shaped Ultra-Wide Band (UWB) antenna with partial ground plane has been presented. The antenna is designed for chipless RFID tags that are working in UWB region. The operating frequency of the antenna is between 2.72 GHz to 11.1 GHz which covers the entire UWB frequency band. The antenna exhibits comparatively high realized gain of 4.2 dBi with respect to its small size of 27 x 40 mm(2) and have a gain to aperture ratio of 0.243 which is comparatively higher than other existing retransmission-based chipless RFID antennas. Another aspect of this antenna is its total efficiency which never goes below 80% throughout the entire bandwidth whereby it reaches as high as 96% at 3.5GHz. This design will motivate the chipless RFID designers to produce small size and cost effective tags.

关键词： RFID   antenna   chipless tag   reader   UWB-IR   backscatter   amplitude  

摘要： A novel methodology is proposed to reliably predict the resonant characteristics of a multipatch backscatter-based radio frequency identification (RFID) chipless tag. An ultra-wideband impulsion radio (UWB-IR)-based reader interrogates the chipless tag with a UWB pulse, and analyzes the obtained backscatter in the time domain. The RFID system consists of a radar cross-section (RCS)-based chipless tag containing a square microstrip patch antenna array in which the chipless tag is interrogated with a UWB pulse by an UWB-IR-based reader. The main components of the backscattered signal, the structural mode, and the antenna mode were identified and their spectral quality was evaluated. The study revealed that the antenna-mode backscatter includes signal carrying information, while the structural mode backscatter does not include any tag information. The simulation findings were confirmed by experimental measurements obtained in an anechoic chamber environment using a 6-bit multipatch chipless RFID tag. Finally, the novel technique does not use calibration tags and can freely orient tags with respect to the reader.

关键词： ECC   Communication   Wireless networking   RFID   Security analysis  

摘要： With the rapid development of microelectronics devices and the progress in communication and information technologies, many services and technologies are increasingly involved into our daily life. In fact, as the used systems are progressively interconnected and open, this introduce new threats such as more and more hacking, fraud and many other kinds of misuses. Consequently, the security and privacy of the exchanged data information tampering must be addressed most seriously. In this context, recently Elliptic Curve Cryptography (ECC) is widely used in many cryptosystems nowadays especially for those presenting challenging constraints in terms of power consumption, memory, computational cost, etc. It is well-known that the ECC provides high security level with much smaller key sizes. In this paper, we show that an inappropriate use of ECC cryptographic primitives, the lack of experience in designing secure protocols and the unsuitable choice of security verification tools can destroy the whole security of a given ECC-based scheme. Therefore, first we wreck efficient attacks on three most recent proposed ECC-based protocols published in three of well-known scientific journals. Then, an improved protocol that inherits the strengths of Dinarvand and Barati's protocol and takes into account the discovered flaws is proposed. Via formal and informal security models, we assess that the improved protocol could deliver all the virtues of Dinarvand and Barati's protocol and resists all known attacks.

关键词： Particle swarm optimization   Radio frequency identification   RFID network planning   K-means algorithm   Virtual force  

摘要： The radio frequency identification (RFID) technology is widely used for object identification and tracking applications, which brings the most challenging RFID network planning (RNP) problem. However, existing RNP methods have some defects, such as the number of readers is uncertain and objectives conflict each other. In this paper, we propose a hybrid particle swarm optimization algorithm with K-means clustering and virtual forces for RNP, which is named as HPSO-RNP. HPSO-RNP can search the number of readers automatically and initialize the coordinates of readers through the K-means algorithms. Virtual force is integrated into the random movement to adjust the location of readers during the search process of PSO. Moreover, we consider four objective functions in a hierarchical manner. To compare HPSO-RNP with the existing method, extensive experiments are conducted on eight RNP benchmark datasets and the results validate that the performance of the proposed method is superior for planning RFID networks in terms of the number of readers, interference, power and load balance.

关键词： wearable   MEMS   respiratory   wireless   RFID   piezoelectric   RF MEMS  

摘要： In this work, we present a battery-less wireless Micro-Electro-Mechanical (MEMS)-based respiration sensor capable of measuring the respiration profile of a human subject from up to 2 m distance from the transceiver unit for a mean excitation power of 80 mu W and a measured SNR of 124.8 dB at 0.5 m measurement distance. The sensor with a footprint of similar to 10 cm(2) is designed to be inexpensive, maximize user mobility, and cater to applications where disposability is desirable to minimize the sanitation burden. The sensing system is composed of a custom UHF RFID antenna, a low-loss piezoelectric MEMS resonator with two modes within the frequency range of interest, and a base transceiver unit. The difference in temperature and moisture content of inhaled and exhaled air modulates the resonance frequency of the MEMS resonator which in turn is used to monitor respiration. To detect changes in the resonance frequency of the MEMS devices, the sensor is excited by a pulsed sinusoidal signal received through an external antenna directly coupled to the device. The signal reflected from the device through the antenna is then analyzed via Fast Fourier Transform (FFT) to extract and monitor the resonance frequency of the resonator. By tracking the resonance frequency over time, the respiration profile of a patient is tracked. A compensation method for the removal of motion-induced artifacts and drift is proposed and implemented using the difference in the resonance frequency of two resonance modes of the same resonator.

关键词： Authentication   Cryptography   Elliptic Curve Cryptography   Public Key   Radio Frequency Identification   Security   Wireless Sensor Network  

摘要： Radio frequency identification (RFID) is the fastest growing technology in the world today. Thus, wireless communication between tags and readers became an integral part of retail products, library books, personal identifications, and healthcare. The RFID system can provide security features to the data transferred along the network to maintain data privacy, integrity, and confidentiality. Elliptic curve cryptography (ECC) is widely used in RFID authentication protocols to improve communication security. Zhao proposed an RFID authentication protocol using ECC where a unique access list for tags is generated with the reader identifier to elevate the security level. Although Zhao's protocol can withstand most of the RFID security attacks, it has a very high computation cost. The authors improve Zhao protocol and propose a new RFID authentication protocol by reducing the computation cost almost to the half of that in Zhao. The proposed protocol shows a significant improvement in the computation cost.

关键词： RFID   harmonic   NLTL   clutter  

摘要： Harmonic Radio Frequency Identification (RFID) systems have attracted significant interest over the last decade as it provides many benefits over the conventional RFID systems. Harmonic RFID is desired over conventional RFID systems due to reduced self-jamming, location accuracy from dual frequency, and higher phase noise immunity. In a harmonic RFID system, the tag receives instructions from the reader at an RF carrier frequency and replies back at the harmonic of the RF frequency. A nonlinear element consuming very low power at the tag is required to generate the harmonic carrier for the battery-less system. In this review article, a detailed contrast between conventional and harmonic RFID systems is presented. This is followed by different circuit design techniques to generate harmonics and integration techniques to form a fully operable passive harmonic RFID tag. Also, a wide range of applications, especially sensor integration with harmonic RFID's, along with the future trends are presented.

关键词： Target tracking   Visualization   Tracking   Object recognition   Wireless communication   Computer vision   Cameras   Radio-frequency identification (RFID)   sensing   mobile tracing   perception fusion  

摘要： We propose to study mobile object tracing, which allows a mobile system to report the shape, location, and trajectory of the mobile objects appearing in a video camera and identifies each of them with its cyber-identity (ID), even if the appearances of the objects are not known to the system. Existing tracking methods either cannot match objects with their cyber-IDs or rely on complex vision modules pre-learned from vast and well-annotated datasets including the appearances of the target objects, which may not exist in practice. We design and implement TagAttention, a vision-RFID fusion system that achieves mobile object tracing without the knowledge of the target object appearances and hence can be used in many applications that need to track arbitrary un-registered objects. TagAttention adopts the visual attention mechanism, through which RF signals can direct the visual system to detect and track target objects with unknown appearances. Experiments show TagAttention can actively discover, identify, and track the target objects while matching them with their cyber-IDs by using commercial sensing devices in complex environments with various multipath reflectors. It only requires around one second to detect and localize a new mobile target appearing in the video and keeps tracking it accurately over time.

关键词： miticides   acaricides   Varroa destructor   RFID   continuous weight measurement  

摘要： Chemical miticides are used routinely in honey bee colonies worldwide as treatment for the parasitic mite Varroa destructor, but there have been very few long-term colony-level field studies of the impacts of miticides on the bees themselves. Lab-based studies with individual bees or bees in small groups have highlighted many negative effects of miticides on bee behaviour and physiology;hence, there is an urgent need to better understand the consequences of miticides on honey bee colonies in an apicultural setting. Here we compared effects of commercial treatments of the miticides tau-fluvalinate and thymol, and controls, on honey bee colonies and bee foraging behaviour over five months, from autumn through winter in Sydney, Australia. Since V. destructor does not occur in Sydney, in this study, we could isolate the direct effects of the miticides from indirect effects resulting from reduced mite load. We found the autumn treatment of either miticide caused no significant change in bee adult or brood population or size of food stores. The average temperature in the thymol group differed from the temperature in the control group and was lower during winter. Neither miticide reduced bee longevity. Tau-fluvalinate caused bees to start foraging earlier in life and perform shorter trips, but no other effects on foraging behaviour were documented. To conclude, in Sydney, Australia, limited negative effects of autumn thymol or tau-fluvalinate treatments were observed on bees or bee colony performance.

关键词： Radiofrequency identification   Antennas   Genetic algorithms   Transmitting antennas   Passive RFID tags   Location awareness   Statistics   Radio-frequency identification (RFID)   3-D indoor localization   network planning   restricted genetic algorithm (RGA)   path loss characteristics (PLC)  

摘要： Indoor localization via radio-frequency identification (RFID) carries critical importance due to its high accuracy and low hardware requirement. The positions of reader antennas can affect the positioning accuracy and coverage in RFID network. In this letter, we present a novel RFID network planning (RNP) approach to optimize the deployment of reader antennas for accurate 3-D location. First, the 3-D antenna radiation mode of a passive UHF RFID system is set up. Then, the received signal strength (RSS) and path loss characteristics (PLC) are analyzed and a restricted genetic algorithm (RGA) is developed to obtain the optimal solution of the RNP via maximizing the total reward function with constraints. Finally, the convolutional neural network (CNN) and weighted K-nearest neighbor (WKNN) algorithms are respectively used to verify the localization effect. For comparison, the Cramer-Rao lower bound (CRLB) is also derived. The experimental results show that the proposed approach can improve the positioning accuracy as well as the coverage, and enhance the anti-noise capability of the location system.