Electronic Article Surveillance Research Articles

Numerical assessment of induced electric fields in a worker’s hand with commonly used metallic implants under exposure to low frequency magnetic fields

The European Union’s Workers’ Directive 2013/35/EU on the minimum health and safety requirements regarding the exposure of workers to electromagnetic fields specifies action levels (ALs) for external electric and magnetic fields, which should protect against induced tissue-internal electric field strength E i above the exposure limit values, the latter being defined in order to prevent tissue stimulation at low frequencies. However, although 2013/35/EU explicitly calls for the protection of ‘workers at particular risk’ (including workers with metallic implants), the AL specified in the Directive have been derived under the assumption that there are no metallic parts present inside the body. Therefore, in the present work, we analysed the situation of a worker’s hand and forearm bearing metallic implants (Herbert screw and volar radius plate) used for osteosynthesis after the most common bone fractures of the hand/forearm, exposed to low frequency magnetic fields. The uniform exposure of the whole hand and forearm as well as the exposure to a specific and widely used device, a deactivator for single-use labels of acousto-magnetic electronic article surveillance systems, were considered based on numerical computations using a high-resolution anatomical hand and forearm model. The results obtained indicated that the maximum induced electric field strength averaged in a volume of 2 mm × 2 mm × 2 mm cube was higher in the presence of the metallic implants by a factor of up to 4.2 for bone tissue and 2.3 for soft tissue compared with the case without an implant. Hence, it is obvious that the local induced electric field strengths may be substantially increased by the implants. The extent of this increase, however, is highly dependent on the implant’s position inside the body, the implant’s geometry, and the field distribution and orientation with respect to the anatomical structure and the implant.

A concise high‐efficiency broadband parallel‐circuit Class‐E power amplifier

SummaryAn analysis of a single‐ended high‐efficiency broadband parallel‐circuit (PC) Class‐E power amplifier (PA) with a single reactance compensation technique (RCT) and low‐pass (LP) Chebyshev impedance transformer is first presented under low supply voltage. Analysis of the gate and drain voltage allows to determine the required optimum voltage values for the expected PA design objectives. Derivation and design procedure of the broadband matching network (MN) is provided, which can effectively filter out higher order harmonics and reduce circuit complexity. In addition, the load adaptability for this PA is studied, achieving higher than 67.87% drain efficiency (DE) in the case of load mismatch. A PC Class‐E PA based on NMOS transistor is designed and implemented to validate the analysis over a frequency band of 7–9.4 MHz. Experimental results show that the PA delivers 36.48–38.83 dBm output power with a DE of 84.91% to 86.91%, as well as achieves 83.98% to 86.28% power‐added efficiency (PAE), 19.48–21.83 dB gain with a low supply voltage of 12 V. It is also demonstrated that the experimental results exhibit good agreement with the simulation results, which prototype the radio frequency identification transmitter with broadband high‐efficiency and system compactness. To the author's knowledge, this study represents the first approach to design broadband PC Class‐E PA under low supply voltage for Internet of Things (IoT) applications at HF frequency band, such as electronic article surveillance (EAS) system.

Dual Antenna-Based Line Crossing Detection with UHF RFID

Line crossing detection is to check whether people or objects go across a given barrier line, which is quite common and important in our daily life, such as the electronic article surveillance (EAS) checkpoint in a retail store or the finish line in track and field. Although existing solutions to line crossing detection have achieved great advancement, they do not function well when multiple objects or people cross the line at the same time. In this paper, we propose a new radio frequency identification (RFID)-based solution called RF-Line to line crossing detection, especially for multiobject scenarios. The biggest challenge is that the RFID reader’s coverage zone is invisible and irregular; we cannot roughly take the time when a tag is seen by the reader for the first time as the time when line crossing occurs. In RF-Line, we deploy two antennas opposite to each other and collect the RF phase profiles of two antennas at the same time. By a series of geometric transformations and mathematical derivations, we find that summing up the two phase profiles will get a new phase curve, in which the inflection point of the curve is the time of line crossing. In addition, we address the problem of turning back or long stay on the barrier line. We implement RF-Line with commodity RFID systems. Extensive experiments show that RF-Line can achieve accurate line crossing detection with a small error of 6.1 cm, with no need for any system calibration or complicated deployment.

Effect of direct voltage induction by low-frequency security systems on neurostimulator lead.

Low-frequency (LF) security systems, such as antitheft electronic article surveillance (EAS) gates emit strong magnetic fields that could potentially interfere with neurostimulator operation. Some patients reported pain and shocking sensations near EAS gates, even after they turned off their pulse generator. To investigate the direct voltage induction of EAS systems on neurostimulator leads, we evaluated voltages induced by two EAS systems (14 kHz continuous wave or 58 kHz pulsed) on a 40 cm sacral neurostimulator lead formed in a circular loop attached to a pulse generator that was turned off. The lead and neurostimulator were mounted in a saline-filled rectangular phantom placed within electromagnetic fields emitted by EAS systems. The measured voltage waveforms were applied to computational models of spinal nerve axons to predict whether these voltages may evoke action potentials. Additional in vitro testing was performed on the semicircular lead geometry, to study the effect of lead geometry on EAS induced voltages. While standard neurostimulator testing per ISO 14708-3:2017 recommends electromagnetic compatibility testing with LF magnetic fields for induction of malfunctions of the active electronic circuitry while generating intended stimulating pulses, our results show that close to the EAS antenna frames, the induced voltage on the lead could be strong enough to evoke action potentials, even with the pulse generator turned off. This work suggests that patient reports of pain and shocking sensations when near EAS systems could also be correlated with the direct EAS-induced voltage on neurostimulator lead.

Nonsinusoidal in situ electric field caused by magnetic deactivator device for EAS labels—assessment of field strength inside a detailed anatomical hand model

In order to evaluate the localised magnetic field (MF) exposure of the cashier’s hand due to a particular demagnetization device (deactivator) for single-use labels of an acoustomagnetic (AM) electronic article surveillance (EAS) system, comprehensive measurements of the MF near the surface of the deactivator, and numerical computations of the induced electric field strength E i, were performed in high-resolution anatomical hand models of different postures and positions with respect to the deactivator. The measurement results for magnetic induction B were assessed with respect to the action levels (AL) for limb exposure, and the computational results for E i were evaluated with respect to the exposure limit values (ELV) for health effects according to European Union (EU) directive 2013/35/EU. For the ELV-based assessment, a maximum of the 2 × 2 × 2 mm3 averaged E i (maxE i,avg) and the respective 99.9th, 99.5th, and 99.0th percentiles were used. As the MF impulse emitted by the deactivator for demagnetization of the AM-EAS labels was highly nonsinusoidal, measurement results were assessed based on the weighted peak method in the time domain (WPM-TD). A newly developed scaling technique was proposed to also apply the WPM-TD to the assessment of the (nonsinusoidal) E i regarding the ELV. It was used to calculate the resulting WPM-TD-based exposure index (EI) from frequency domain computations. The assessment regarding the AL for limbs yielded peak values of magnetic induction of up to 97 mT (measured with a 3 cm2 MF probe on top of the deactivator surface) corresponding to an EI of 443%. However, this was considered an overestimation of the actual exposure in terms of E i as the AL were intentionally defined conservatively. A WPM-TD-based assessment of E i finally led to the worst case EI of up to 135%, 93%, 78%, and 72% when using the maxE i,avg, 99.9th, 99.5th, and 99.0th percentiles, respectively.

Measurement and Exposure Assessment of Intermediate Frequency Magnetic Fields From Electronic Article Surveillance (EAS) Gates in Libraries.

Exposure to magnetic fields from the electronic article surveillance (EAS) gate was evaluated in consideration of the application to epidemiological studies of library workers who are exposed continually to intermediate frequency magnetic fields from the EAS gate. Two types of exposures were investigated. One was transient exposure due to passing through or beside the gate and another was chronic exposure in the room. We measured magnetic fields from five EAS gate models which were commonly used in libraries in Japan. Detailed measurements were performed for two of them in consideration of the phase difference of vector components of magnetic flux density. The polarization of the magnetic field in the gate was investigated with the index of ellipticity. The induced electric field in a human body was numerically calculated for exposures to magnetic fields of the two gate models. The results provide a quantitative understanding of exposures during passing through or by the EAS gate. Magnetic field distribution was measured in a large room for one gate model to quantify the chronic exposure of library workers during the work at the desk. It was found that the magnetic field was distributed as a function of the horizontal distance to the nearest gatepost. The 45-point average value BIEC defined by the IEC standard was suggested to be a useful quantity to characterize the magnitude of the magnetic field from the EAS gate. Exposures to different EAS gates are expected to be compared through this quantity without detailed measurements. These results are expected to provide useful means for exposure assessment of epidemiological studies on the association between the IF-EMF exposure and possible health outcomes.

Supermarket Operators’ Perception of Effects: Shoplifting Crimes Within the CBD In Nairobi County, Kenya

This paper established prevalence of the characteristics in the shoplifting crimes and determined the supermarket operators’ perception of the effects of shoplifting crimes on society. The study was guided by three objectives: to establish offender characteristics of the shoplifting crimes, to establish prevalence of the characteristics in the shoplifting crimes and to determine the supermarket operators’ perception of the effects of shoplifting crimes on society. The study was guided by Rational Choice and the Routine Activity Theories. The study used a census sampling technique with a sample size of a hundred respondents. These included 90 junior employees of Tuskys, Uchumi and Naivas Supermarkets, 3 branch managers, 3 police officers within the area of the study and 4 officials of the Nairobi Supermarkets Association. Interview schedule was used to collect data. Data collected was organized, summarized and interpreted thematically by use of graphs, frequency tables, and percentages. The findings revealed that the prevalence of shoplifting was 1-2 incidences in a week. The results also revealed that the most commonly used method was concealing of items which were majorly done by women. Further, whereas there are other types of shoplifters, a concern raised by 30% of the respondents is that significant number of criminals has made shoplifting a career. This should inform policy makers, especially in this era of unprecedented unemployment. Additionally, as indicated by 55% of the respondents, staff colluded with criminals to steal from the supermarkets. This should appeal to supermarket operators as this may have an implication on supermarket businesses in the CBD. The study recommends several target hardening strategies to counter shoplifting crimes that included using high Radio-frequency identification (RFID) and Electronic Article Surveillance (EAS) programmed surveillance and records linked to the law enforcement through alarm trigger alerts in case of suspicious activities, with high-quality identifiable traceable images of shoplifters, to local law enforcement agencies.

A Modified Design of Class-E Power Amplifier with Balanced FETs and High Output Power for RFID Applications

In Radio Frequency (RF) communication, a Power Amplifier (PA) is used to amplify the signal at the required power level with less utilization of Direct Current (DC) power. The main characteristic of class-E PA is sturdy nonlinearity due to the switching mode action. In this study, a modified design of class-E PA with balanced Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) and high output power for Electronic Article Surveillance (EAS) Radio Frequency Identification (RFID) application is presented. MOSFETs are adjusted to have high output performance of about 80% for RFID-based EAS system. A matching network is also proposed for accurate matching because there are differences in the behavior between RF waves and low frequency waves. The design of a matching network is a tradeoff among the complexity, adjustability, implementation, and bandwidth for the required output power and frequency. The implemented PA is capable of providing 44.8 dBm output power with Power-Added Efficiency (PAE) of 78.5% at 7.7 MHz to 8.7 MHz.

JCS/JHRS 2019 guideline on non-pharmacotherapy of cardiac arrhythmias.

JCS/JHRS 2019 guideline on non-pharmacotherapy of cardiac arrhythmias.

Electronic Surveillance and Security Applications of Magnetic Microwires

Applications in security and electronic surveillance require a combination of excellent magnetic softness with good mechanical and anticorrosive properties and low dimensionality. We overviewed the feasibility of using glass-coated microwires for electronic article surveillance and security applications, as well as different routes of tuning the magnetic properties of individual microwires or microwire arrays, making them quite attractive for electronic article surveillance and security applications. We provide the routes for tuning the hysteresis loops’ nonlinearity by the magnetostatic interaction between the microwires in the arrays of different types of amorphous microwires. The presence of neighboring microwire (either Fe- or Co-based) significantly affects the hysteresis loop of the whole microwires array. In a microwires array containing magnetically bistable microwires, we observed splitting of the initially rectangular hysteresis loop with a number of Barkhausen jumps correlated with the number of magnetically bistable microwires. Essentially, nonlinear and irregular hysteresis loops have been observed in mixed arrays containing Fe- and Co-rich microwires. The obtained nonlinearity in hysteresis loops allowed to increase the harmonics and tune their magnetic field dependencies. On the other hand, several routes allowing to tune the switching field by either postprocessing or modifying the magnetoelastic anisotropy have been reviewed. Nonlinear hysteresis loops have been also observed upon devitrification of amorphous microwires. Semihard magnetic microwires have been obtained by annealing of Fe–Pt–Si microwires. The observed unique combination of magnetic properties together with thin dimensions and excellent mechanical and anticorrosive properties provide excellent perspectives for the use of glass-coated microwires for security and electronic surveillance applications.

An Optimal Design of High Output Power CMOS Class E Power Amplifier with Broadband Matching for RFID Applications

In the radio frequency frontend the power amplifiers are most essential block for reliable wireless communication. Power amplifiers are used for amplification and enhance the input signal to the desired power level at output. The class-E power amplifiers are used in many RF portable electronic devices that need low power consumption, high gain, and high efficiency. In this article, we present an optimum design of a complementary metal-oxide semiconductor (CMOS) class-E power amplifier (PA) that achieves high efficiency and high gain simultaneously for RF based electronic article surveillance (EAS) system. The simulated analysis and implementation of a class-E RF power amplifier with an appropriate output impedance matching network are presented. The proposed CMOS class-E PA has 41.7 dBm output power with 63% of power efficiency at frequency of 7.7 MHz to 8.7MHz.

Catch me if you scan: Data-driven prescriptive modeling for smart store environments

The increasing adoption of omnichannel strategies in recent years has led retail companies worldwide to fundamentally rethink the future role of their network of brick-and-mortar stores. One strategic option being pursued by many retailers is the transformation of the stationary store into a “smart store,” augmented by various digital services. However, an essential prerequisite for the success of smart store services is high quality of the underlying data generated through the use of technologies for tracking products and customer behavior. As a means of investigating the use of machine learning to improve data quality, the present study considers the example of Radio Frequency Identification (RFID) as a technological infrastructure for tracking products in fashion retail. We examine electronic article surveillance and automated checkouts as practical use cases enabled by a classification model for the detection of product movements on the store floor. In order to identify an economically optimal configuration of the classifier, we develop a complementary service operations model that allows for determining the respective cost impact. In addition to the specific results for the considered use cases, the study thus points to a general and novel prescriptive analytics approach.

Modified Planar Square-Loop Antenna for Electronic Article Surveillance Radio Frequency Identification Applications

In this paper, a modified design of a planar square-loop antenna is presented for Electronic Article Surveillance (8.2 MHz) Radio Frequency Identification applications. The main purpose of the proposed design is to enhance the transmission efficiency of a loop antenna without disturbing other performance parameters. For that purpose, the spacing between the loop turns is adjusted in such a way that the coupling between similar loop antennas can be enhanced. Therefore, from measured results, it is observed that the proposed antenna provides a transmission efficiency of 63.92% at a center frequency of 8.198 MHz, and it also provides a –10 dB impedance bandwidth of 6 kHz.

Magnetostriction measurements with a low-cost magnetostrictive cantilever beam

The magnetostrictive effect is an important topic for scientific research as well as for technological applications. Since magnetostriction constitutes an important property of emerging smart materials, experimental investigations as well as theoretical discussions of the magnetostrictive effect are of great educational value. Quantitative measurements of the magnetostrictive effect are usually technically sophisticated or not related to real applications or everyday materials. The objective of this article is to describe a simple and low-cost experiment for the qualitative and quantitative investigation of magnetostrictive characteristics employing magnetostrictive laser deflection and optical amplification. Measurements are performed for precut magnetostrictive materials found in electronic article surveillance tags. Comparative theoretical calculations for magnetostrictive cantilever beams prove the quality of the experimental approach. The described method for magnetostriction measurements has been developed as a part of the Scientific Outreach Project within the Collaborative Research Centre (CRC) 1261 “Magnetoelectric Sensors.”

A Comparative Survey on Silicon Based and Surface Acoustic Wave (SAW)-Based RFID Tags: Potentials, Challenges, and Future Directions

Many Automatic Identification (Auto-ID) technologies such as bar codes, magnetic stripes, Optical Character Recognition (OCR) and Electronic Article Surveillance (EAS) security tags are in existence. However, they are limited by a variety of constraints on them such as limited object rate of scan, need for Line-of-Sight (LOS) operation, very small interrogation range and poor accuracy in complex environments. Research has accordingly grown rapidly in recent years into the development of robust identification or tracking mechanisms. Radio Frequency Identification (RFID) technology using readers and RFID tags, whether passive, semi-passive or active in nature, has been deemed to be a promising candidate. Silicon based IC tags are quite popular. However, some alternative RFID technologies have also been on the rise. In particular, another special type of tag based on Surface Acoustic Wave (SAW) design also has a great potential for deployment in future identification fields due to its ruggedness against harsh conditions, metallic environments, interference, small and low cost and is being thoroughly reviewed, which is ignored in other survey papers. While other chipless RFID systems based on conductive ink, ink-tattoo and others do exist, negative aspects such as inability to survive in extreme weather, larger tag size and limited data storage capacity have severely impacted the penetration of such tags in the RFID market. Therefore, the scope of this survey article does not include chipless RFID tags. This article instead provides a comparative survey of silicon based IC and SAW based tags, which has attracted much attention from both academia and industry. The underlying characteristics, principles, advantages, and limitations of such tags are thoroughly discussed, and relevant research work followed by frequency of operation and other parameters are elaborated. This article undertakes a thorough investigation into the evolution of RFID technology and comparison into the current trend in silicon based IC and SAW based RFID tags and provides a comparison across many metrics, such as read range, tag size, tag power, availability of tag power, lifespan and more importantly, cost and security. It discusses active and passive tags under silicon based IC and SAW technology. Finally, the article reviews recent advances and provides potentials, open challenges and future research directions in such RFID tags. © 2013 IEEE.

A Ferrite-Filled Cavity Resonator for Electronic Article Surveillance on Metallic Packaging

Conventional electronic article surveillance (EAS) tags are ineffective on metallic packaging. The component of the RF magnetic field perpendicular to the surface of the packaging induces eddy currents that suppress the magnetic flux, linking the inductive element of the tag. In this article, an inductive quarter-wavelength planar cavity, formed by wrapping aluminum foil around a ferrite core, was extended by wrapping additional capacitive layers of foil/dielectric around the ferrite-filled central region. This so-called wrapped tag exhibits the frequency, $Q$ -factor, and read distance characteristics of existing EAS tags, but is instead driven by the RF magnetic fields parallel to the surface of the metallic packaging. In this article, we compare the observed frequency response of the wrapped tag with a simple LC resonator model that considers the tag’s geometrical features, and use the model to describe how the design and construction of the tag can be optimized. Finite-element method (FEM) modeling is used to reveal how the current flows in the wrapped foil of the tag. Prototype tags show good reproducibility, demonstrating the potential of the design as a solution to the problem of tagging metallic packaging in the EAS industry.

Effectiveness of RFID Technology in Library Management System in Bangladesh

The purpose of the study is to evaluate the effectiveness of Radio Frequency Identification (RFID) technology in library management system and services in Bangladesh. This study followed survey and interview methods of data collection through a structured questionnaire. The population of study was all nine libraries in Bangladesh where RFID technology has been installed. The study reveals that all nine libraries are using RFID technology, namely, anti-theft detection Electronic Article Surveillance (EAS) gate, staff-work station and RFID tag. In addition to these, some of them are using kiosk, converter, level printer, book drop station, digital library assistance (DLA) and RFID smart card for entrance. The significance numbers of library users employ the RFID system and services and it is increasing gradually, but some of the RFID machines like level printer, book drop station and DLA are under-utilized because of lack of trained staff, patron’s doubt on new technology and less demand on using them in house-keeping library operation.

A pilot study on the reproductive risks of maternal exposure to magnetic fields from electronic article surveillance systems

Purpose: We investigated the feasibility of a large-scale epidemiological study on reproductive effects of intermediate frequency (IF) magnetic field (MF) exposure among cashiers working near electronic article surveillance (EAS) systems.Materials and methods: The study cohort included 4157 women who had worked as cashiers in supermarkets with EAS devices (considered as exposed) or grocery stores without EAS devices (considered as unexposed) between 2008 and 2015. 536 births and 38 miscarriages occurred among these women during the study period, based on information from nationwide health registries. Measurements were also performed to characterize the MF exposure of cashiers.Results: Cashiers were found to be exposed to 8.2 MHz MFs only when passing by the gates at short distance. Static fields of about 0.1 mT were observed at cashier’s seat. Extremely low frequency MFs were higher at stores without EAS devices. No differences on the risk of miscarriage, reduced birth weight or preterm birth were observed between cashiers in different store types.Conclusions: Any further studies should attempt to include study subjects working near EAS systems that produce stronger IF MFs at kHz frequencies. Exposure to ELF MFs should be assessed as a possible confounding factor.

Behavioural phenotypes in mice after prenatal and early postnatal exposure to intermediate frequency magnetic fields

Electromagnetic fields are ubiquitous in the environment. Human exposure to intermediate frequency (IF) fields is increasing due to applications like electronic article surveillance systems, wireless power transfer, and induction heating cooking hobs. However, there are limited data on possible health effects of exposure to IF magnetic fields (MF). In the present study, we set out to assess cognitive and behavioural effects of IF MF in mice exposed during prenatal and early postnatal periods. Pregnant female mice were exposed continuously to 7.5kHz MFs at 12 and 120μT, from mating until weaning of pups. Sham exposed pregnant mice were used as a control group. A behavioural teratology study was conducted on the male offspring at two months of age to detect possible effects on the developing nervous system. Body weight development did not differ between the exposure groups. The exposure did not alter spontaneous motor activity when exploring a novel cage or anxiety in novelty-suppressed feeding or marble burying tests. Improved performance in the Rotarod task was observed in the 12µT group, while the 120μT exposure group swam more slowly than the sham exposed group in the Morris swim navigation task. However, indices of learning and memory (path length and escape latency during task acquisition and search bias during the probe test) did not differ between the exposure groups. Furthermore, the passive avoidance task did not indicate any impairment of long-term memory over a 48h interval in the exposed groups. In a post-mortem histopathological analysis, there was no evidence for an effect of IF MF exposure on astroglial reactivity or hippocampal neurogenesis. The results suggest that the IF MF used did not have detrimental effects on spatial learning and memory or histological markers of tissue reaction. The two statistically significant findings that were observed (improved performance in the Rotarod task in the 12µT group and decreased swimming speed in the 120µT group) are likely to be chance findings, as they do not form an internally consistent, dose-dependent pattern indicative of specific developmental effects.

Behavioral testing of mice exposed to intermediate frequency magnetic fields indicates mild memory impairment.

Human exposure to intermediate frequency magnetic fields (MF) is increasing due to applications like electronic article surveillance systems and induction heating cooking hobs. However, limited data is available on their possible health effects. The present study assessed behavioral and histopathological consequences of exposing mice to 7.5 kHz MF at 12 or 120 μT for 5 weeks. No effects were observed on body weight, spontaneous activity, motor coordination, level of anxiety or aggression. In the Morris swim task, mice in the 120 μT group showed less steep learning curve than the other groups, but did not differ from controls in their search bias in the probe test. The passive avoidance task indicated a clear impairment of memory over 48 h in the 120 μT group. No effects on astroglial activation or neurogenesis were observed in the hippocampus. The mRNA expression of brain-derived neurotrophic factor did not change but expression of the proinflammatory cytokine tumor necrosis factor alpha mRNA was significantly increased in the 120 μT group. These findings suggest that 7.5 kHz MF exposure may lead to mild learning and memory impairment, possibly through an inflammatory reaction in the hippocampus.