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关键词： RFID   Cross-technology   VLC  

摘要： The ubiquity of illumination facilities enables the versatile development of Visible Light Communication (VLC). VLC-based research achieved high-speed wireless access and decimeter-level indoor localization with complex equipment. However, it is still unclear whether the VLC is applicable for widely-used battery-free Internet-of-Things nodes, e.g., passive RFIDs. This paper proposes LightSign, the first cross-technology system that enables passive RFID tags to receive visible light messages. LightSign is compatible with commercial protocols, transparent to routine RFID communications, and invisible to human eyes. We propose a pseudo-timing instruction to achieve microsecond-level light switching to modulate the VLC message. To make it perceptible to passive RFIDs, we design an augmented RFID tag and prove its effectiveness theoretically and experimentally. With only one reply from an augmented tag, LightSign can decode 100-bit-long VLC messages. We evaluate LightSign in real industry environments and test its performance with two use cases. The results show that LightSign achieves up to 99.2% decoding accuracy in varying scenarios.

关键词： RFID reader   Cortex M0   digital baseband   SoC  

摘要： The traditional RFID reader module relies on a discrete original design. This design integrates a microcontroller, high-frequency RFID reader IC and other multiple chips onto a PCB board, leading to bottlenecks in cost, power consumption, stability and reliability. To align with the trend towards high integration, miniaturization and low power consumption in RFID reader, this paper introduces a fully integrated RFID Reader SoC. The SoC employs the open-source Cortex-M0 core to integrate the RF transceiver, analog circuits, baseband protocol processing, memory and interface circuits into one chip. It's compatible with ISO/IEC 14443 A-type and B-type and ISO/IEC 15693 transmission protocols and rates. Manufactured using a 0.18 mu m process, the chip is compatible with multiple standards. The optimized design of the digital baseband control circuit results in a chip area of only 11.95 mm2 offering clear advantages in both area and integration compared to similar work.

关键词： Physical sensors   chipless radio frequency identification (RFID)   industry 4.0   Internet of Things (IoTs)   light switch   wireless powering   wireless sensors  

摘要： This letter introduces a tactile light switch (TLS) that is passive, battery free, and relocatable. The switch utilizes physical touch to control electrical devices, such as light bulbs and TVs. TLS is a chipless radio frequency identification (RFID) tag with an integrated tactile-sensitive element. It is achieved by incorporating three radio frequency spiral resonators, namely, a sensing resonator and two identification (ID) resonators. Each resonator is designed with a unique resonant frequency that is used to passively communicate the status of the TLS tag. The sensing resonator is touch sensitive, and the presence of its corresponding resonant frequency (f(RS)) is controlled by touch. The ID resonators have fixed resonant frequencies (f(IDR1,2)) that are used for tag identification. The TLS tag is designed and fabricated using a 1.6-mm-thick FR4 substrate. The measurement results show resonant frequencies at 1.02, 1.08, and 1.19 GHz, corresponding to f(RS), f(IDR1), and f(IDR2), respectively. A direct touch on the surface of the sensing resonator successfully cancels the resonant frequency at f(RS), whereas the resonances at f(IDR1,2) are unaffected by touch and are always present for identification.

关键词： RFID   Carbon dioxide sensor   ZnO   Semiconductor  

摘要： Metal oxides are one of the hot research directions of sensors. Their low cost, high sensitivity, short response time, short recovery time and other advantages have attracted much attention in the field of gas detection. An RFID carbon dioxide sensor based on ZnO/CuO/RGO nanocomposite layer is proposed, which can respond quickly. The ZnO nano materials we prepared by hydrothermal method are rod materials with high specific surface area, and the nano CuO is petal shaped. The heterojunction formed by the two increases the gas adsorption sites, reduces the activation energy when reacting with carbon dioxide, and is also highly sensitive to carbon dioxide at room temperature. Then we use the reduced graphene oxide to change its physical properties and improve the conductivity of semiconductor materials. The sensor determines the amplitude of carbon dioxide concentrationAt room temperature, the amplitude of the sensor varies from -24.0 dB to -13.0 dB. The sensor can quickly respond to and recover from the carbon dioxide concentration of 500 ppm-1600 ppm, and the recovery time varies from 30s to 60s. Compared with the traditional carbon dioxide sensor which needs higher working temperature, this paper designs a carbon dioxide sensor. This RFID carbon dioxide sensor has good temperature adaptability, reversibility, repeatability, low cost and other characteristics, and can be widely used in fruit and vegetable storage, transportation, agricultural greenhouses, indoor environmental monitoring and other fields.

关键词： Delivery ratio   Efficiency   Energy   IoT   Network   Population   Protocol   RFID   Routing   Sensor   Wireless  

摘要： The proliferation of the internet of things (IoT) has led to the widespread adoption of wireless sensor devices that connect physical objects and people to the Internet. Despite their potential, IoT networks are constrained by limited power and memory resources, necessitating the development of efficient routing protocols to ensure long-term operational effectiveness. In response to this challenge, this study introduces a novel deep reinforcement learning energy-efficient routing (DRLEER) approach that optimizes routing decisions by enabling IoT devices to learn from experience and adapt to dynamic network conditions, including energy levels and mobility. The deep reinforcement learning agent is trained on a comprehensive dataset encompassing network topology, traffic patterns, and energy consumption, facilitating the selection of optimal routing decisions. The genetic optimization algorithm is incorporate with effective cluster head identification by considering the factors such as device energy levels and node proximity, DRLEER minimizes energy consumption and extends the lifespan of IoT devices. The proposed method is benchmarked against various existing protocols in terms of scalability, network durability, and energy efficiency. The findings reveal that DRLEER consistently outperforms its counterparts across all metrics, yielding substantial enhancements in network efficiency, energy consumption, and overall performance. © 2023, The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd.

关键词： Household consumption   Laundry   Consumer behaviour   Living lab   Environmental assessments   RFID  

摘要： PurposeMany environmental assessments of consumer products and household services rely on self-reported data. Life cycle assessments of domestic laundering are no exception. However, potential discrepancies between self-reported behaviour and actual everyday decisions are seldom investigated due to practical challenges in collecting relevant data. This means that environmental impacts relying on such self-reported data are much more uncertain than previously *** data was collected at the Chalmers' HSB Living lab (CHSBLL), a combined multi-family house and research facility in Gothenburg. The collection was both done passively (through the washing machines) as well as actively (through surveys to the tenants). RFID-readers were also installed in the machines and a number of clothing items tagged, allowing for identification. The site-specific data was later supplemented with a large statistical representative study for domestic laundering of Swedish households. This unique data quality allowed the comparison of passively collected data with survey data from tenants in a real-life setup, while validating the results from a national *** and conclusionsThe results suggest that consumers have trouble remembering personal choices regarding domestic laundering, meaning that self-reported data are more uncertain than previously thought. In general, the participants overestimated the amount of laundry they washed and underestimated their frequency of washing. Additionally, many participants showed an interest in changing to alternative wash programs although this change failed to materialize when they were presented with this option in real-life. The findings have potential consequences for environmental assessments and implicate those previous estimations underestimate emissions per kg laundry washed.

关键词： Electronic Design Automation   Decomposition   Substitution box   Resource constrained   Logic synthesis  

摘要： This paper investigates three substitution box (S-box) designs for lightweight ciphers. The proposed designs involve functional decomposition, which is preferable as compared to the look-up tables or logic gates-based S-box designs due to their advantages, as outlined in this paper. The aim is to reduce the number of literals at the input of the S-box to achieve resource reduction in the overall circuit design of the encryption algorithms. The proposed S-box architectures provide optimized resource mapping for specific target hardware, and high throughput along with lesser energy consumption compared to state-of-the-art designs. The proposed S-box designs are applied to the substitution layers of symmetric lightweight block ciphers with a standard security level. In order to be fair in comparison, the overall cipher designs are targeted for similar FPGA-based implementation as used in existing works, while the architectures of the individual 4-bit S-boxes are evaluated using SAED90 nm standard cell libraries. The performance of the proposed S-box designs is observed to be superior at RFID and ISM frequency ranges which can be deployed in applications constrained to low resources as well as demanding high performance and medium security.

关键词： Vehicular cloud computing   directed acyclic graph   task scheduling   network dynamics   volatile resources  

摘要： Vehicular cloud (VC) platforms integrate heterogeneous and distributed resources of moving vehicles to offer timely and cost-effective computing services. However, the dynamic nature of VCs (i.e., limited contact duration among vehicles), caused by vehicles' mobility, poses unique challenges to the execution of computation-intensive applications/tasks with a directed acyclic graph (DAG) structure, where each task consists of multiple interdependent components (subtasks). In this paper, we study the scheduling of DAG tasks over dynamic VCs, where multiple subtasks of a DAG task are dispersed across vehicles and processed by vehicles cooperatively. We formulate DAG task scheduling as a 0-1 integer programming problem, aiming to minimize the overall task completion time while ensuring a high execution success rate, which turns out to be NP-hard. To tackle the problem, we develop a ranking and foresight-integrated dynamic scheduling scheme (RFID). RFID consists of i) a dynamic downward ranking mechanism that sorts the scheduling priority of different subtasks, while explicitly taking into account the sequential execution nature of DAG;ii) a resource scarcity-based priority changing mechanism that overcomes possible performance degradations caused by the volatility of VC resources;and iii) a degree-based weighted earliest finish time mechanism that assigns the subtask with the highest scheduling priority to the vehicle which offers rapid task execution along with reliable transmission links. Simulation results reveal the effectiveness of our proposed scheme in comparison to benchmark methods.

关键词： cobble   RFID   gravel   beach   California  

摘要： Cobbles provide a nature-based method to help generate beach stability. However, few detailed cobble movement observations exist. This study deployed 344 radio-frequency identification tagged cobbles in a California beach in November-December 2020. Coincident LiDAR surveys quantified beach morphology. Cobbles were mapped daily for 10 days and then similar to monthly until January 2023. Cobble detection rates ranged 17%-92%, and generally declined with time (with slight increases during winter months). Cobble movement exhibited complex patterns, sometimes moving in opposing directions during the same time period. Large winter waves (up to similar to 4 m) resulted in average displacements of 40 m per month between November 2020 and April 2021. From April 2021 to August 2022, most cobbles were located high on the beach and net alongshore movements were relatively low, despite several moderate size (similar to 2 m) wave events. The largest wave event in January 2023 (>4 m) moved cobbles to the highest elevations of the study period. The initial release location and accommodation space in the back beach influenced cobble movement and final position. Cobbles high on the beach were relatively stable compared to lower elevation cobbles, and more than half of all cobble detections were within 50 m of the initial release location. However, three cobbles moved >500 m. The probability distribution of displacement was approximately exponential. Statistically, alongshore cobble spreading followed a non-Gaussian subdiffusive process. Despite myriad sources of noise, the results suggest that cobble shape and mass were related to maximum cobble displacement. Overall, displacements increased with incident wave energy and depended on elevation relative to total water level.

关键词： RFID   Sleep apnoea   Monopole   ISM   Biomedical  

摘要： This article introduces the design and analysis of a compact, high gain, and wide bandwidth flower-shaped slotted monopole antenna for RFID reader antenna applications. The proposed antenna comprises a flower -shaped radiator with six arc-shaped slots and a partial ground plane. The measurement results indicate a wide operating band in the frequency range of 2.4 GHz-7.6 GHz. The proposed antenna is designed to operate at 5.8 GHz ISM band for RFID reader applications with a peak measured gain of 3.9 dBi. The structure has an overall dimension of 0.782 x 0.582 x 0.032 at an operating frequency of 5.8 GHz and is found compact in comparison to some related designs. The monopole antenna shows an omnidirectional radiation pattern in the operating band and indicates a maximum realized gain value of 4.2 dBi. The study provides a detailed mathematical analysis of the operating principle with surface current distribution plots. The design indicates a reading range of 2.56 cm at 5.8 GHz and the satisfaction of the propagation-test makes the compact, wideband, and high-performance design suitable for different short-range RFID reader applications.