84 research outputs found

    MH-REACH-Mote: supporting multi-hop passive radio wake-up for wireless sensor network

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    A passive wake-up radio in a wireless sensor network (WSN) has the advantage of increasing network lifetime by using a wake-up radio receiver (WuRx) to eliminate unnecessary idle listening. A sensor node equipped with a WuRx can operate in an ultra-low-power sleep mode, waiting for a trigger signal sent by the wake-up radio transmitter (WuTx). The passive WuRx is entirely powered by the energy harvested from radio transmissions sent by the WuTx. Therefore, it has the advantage of not consuming any energy locally, which would drain the sensor node's battery. Even so, the high amount of energy required to wake up a passive WuRx by a WuTx makes it difficult to build a multi-hop passive wake-up sensor network. In this paper, we describe and discuss our implementation of a battery-powered sensor node with multi-hop wake-up capability using passive WuRxs, called MH-REACH-Mote (Multi-hop-Range EnhAnCing energy Harvester-Mote). The MH-REACH-Mote is kept in an ultra-low-power sleep mode until it receives a wake-up trigger signal. Upon receipt, it wakes up and transmits a new trigger signal to power other passive WuRxs. We evaluate the wake-up range and power consumption of an MH-REACH-Mote through a series of field tests. Results show that the MH-REACH-Mote enables multi-hop wake-up capabilities for passive WuRxs with a wake-up range of 9.4m while requiring a reasonable power consumption for WuTx functionality. We also simulate WSN data collection scenarios with MH-REACH-Motes and compare the results with those of active wake-up sensor nodes as well as a low power listening approach. The results show that the MH-REACH-Mote enables a longer overall lifetime than the other two approaches when data is collected infrequently.Peer ReviewedPostprint (author's final draft

    Wearable Quarter-Wave Folded Microstrip Antenna for Passive UHF RFID Applications

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    A wearable low-profile inset-fed quarter-wave folded microstrip patch antenna for noninvasive activity monitoring of elderly is presented. The proposed antenna is embedded with a sensor-enabled passive radio-frequency identification (RFID) tag operating in the ultra-high frequency (UHF) industrial-scientific-medical (ISM) band around 900 MHz. The device exhibits a low and narrow profile based on a planar folded quarter-wave length patch structure and is integrated on a flexible substrate to maximise comfort to the wearer. An extended ground plane made from silver fabric successfully minimises the impact of the human body on the antenna performance. Measurements on a prototype demonstrate a reflection coefficient (S₁₁) of −30 dB at resonance and a −10 dB bandwidth from 920 MHz to 926 MHz. Simulation results predict a maximum gain of 2.8 dBi. This is confirmed by tag measurements where a 4-meter read range is achieved using a transmit power of 30 dBm, for the case where the passive wearable tag antenna is mounted on a body in a practical setting. This represents an almost 40% increase in read range over an existing dipole antenna placed over a 10 mm isolator layer on a human subject.Thomas Kaufmann, Damith C. Ranasinghe, Ming Zhou, and Christophe Fumeau

    Energy efficiency in short and wide-area IoT technologies—A survey

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    In the last years, the Internet of Things (IoT) has emerged as a key application context in the design and evolution of technologies in the transition toward a 5G ecosystem. More and more IoT technologies have entered the market and represent important enablers in the deployment of networks of interconnected devices. As network and spatial device densities grow, energy efficiency and consumption are becoming an important aspect in analyzing the performance and suitability of different technologies. In this framework, this survey presents an extensive review of IoT technologies, including both Low-Power Short-Area Networks (LPSANs) and Low-Power Wide-Area Networks (LPWANs), from the perspective of energy efficiency and power consumption. Existing consumption models and energy efficiency mechanisms are categorized, analyzed and discussed, in order to highlight the main trends proposed in literature and standards toward achieving energy-efficient IoT networks. Current limitations and open challenges are also discussed, aiming at highlighting new possible research directions

    Advanced Radio Frequency Identification Design and Applications

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    Radio Frequency Identification (RFID) is a modern wireless data transmission and reception technique for applications including automatic identification, asset tracking and security surveillance. This book focuses on the advances in RFID tag antenna and ASIC design, novel chipless RFID tag design, security protocol enhancements along with some novel applications of RFID

    Chipless RFID sensor systems for structural health monitoring

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    Ph. D. ThesisDefects in metallic structures such as crack and corrosion are major sources of catastrophic failures, and thus monitoring them is a crucial issue. As periodic inspection using the nondestructive testing and evaluation (NDT&E) techniques is slow, costly, limited in range, and cumbersome, novel methods for in-situ structural health monitoring (SHM) are required. Chipless radio frequency identification (RFID) is an emerging and attractive technology to implement the internet of things (IoT) based SHM. Chipless RFID sensors are not only wireless, passive, and low-cost as the chipped RFID counterpart, but also printable, durable, and allow for multi-parameter sensing. This thesis proposes the design and development of chipless RFID sensor systems for SHM, particularly for defect detection and characterization in metallic structures. Through simulation studies and experimental validations, novel metal-mountable chipless RFID sensors are demonstrated with different reader configurations and methods for feature extraction, selection, and fusion. The first contribution of this thesis is the design of a chipless RFID sensor for crack detection and characterization based on the circular microstrip patch antenna (CMPA). The sensor provides a 4-bit ID and a capability of indicating crack width and orientation simultaneously using the resonance frequency shift. The second contribution is a chipless RFID sensor designed based on the frequency selective surface (FSS) and feature fusion for corrosion characterization. The FSS-based sensor generates multiple resonance frequency features that can reveal corrosion progression, while feature fusion is applied to enhance the sensitivity and reliability of the sensor. The third contribution deals with robust detection and characterization of crack and corrosion in a realistic environment using a portable reader. A multi-resonance chipless RFID sensor is proposed along with the implementation of a portable reader using an ultra-wideband (UWB) radar module. Feature extraction and selection using principal component analysis (PCA) is employed for multi-parameter evaluation. Overall, chipless RFID sensors are small, low-profile, and can be used to quantify and characterize surface crack and corrosion undercoating. Furthermore, the multi-resonance characteristics of chipless RFID sensors are useful for integrating ID encoding and sensing functionalities, enhancing the sensor performance, as well as for performing multi-parameter analysis of defects. The demonstrated system using a portable reader shows the capability of defects characterization from a 15-cm distance. Hence, chipless RFID sensor systems have great potential to be an alternative sensing method for in-situ SHM.Indonesia Endowment Fund for Education (LPDP

    High-throughput large-area plastic nanoelectronics

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    Large-area electronics (LAE) manufacturing has been a key focus of both academic and industrial research, especially within the last decade. The growing interest is born out of the possibility of adding attractive properties (flexibility, light weight or minimal thickness) at low cost to well-established technologies, such as photovoltaics, displays, sensors or enabling the realisation of emerging technologies such as wearable devices and the Internet of Things. As such there has been great progress in the development of materials specifically designed to be employed in solution processed (plastic) electronics, including organic, transparent metal oxide and nanoscale semiconductors, as well as progress in the deposition methods of these materials using low-cost high-throughput printing techniques, such as gravure printing, inkjet printing, and roll-to-roll vacuum deposition. Meanwhile, industry innovation driven by Moore’s law has pushed conventional silicon-based electronic components to the nanoscale. The processes developed for LAE must strive to reach these dimensions. Given that the complex and expensive patterning techniques employed by the semiconductor industry so far are not compatible with LAE, there is clearly a need to develop large-area high throughput nanofabrication techniques. This thesis presents progress in adhesion lithography (a-Lith), a nanogap electrode fabrication process that can be applied over large areas on arbitrary substrates. A-Lith is a self-alignment process based on the alteration of surface energies of a starting metal electrode which allows the removal of any overlap of a secondary metal electrode. Importantly, it is an inexpensive, scalable and high throughput technique, and, especially if combined with low temperature deposition of the active material, it is fundamentally compatible with large-area fabrication of nanoscale electronic devices on flexible (plastic) substrates. Herein, I present routes towards process optimisation with a focus on gap size reduction and yield maximisation. Asymmetric gaps with sizes below 10 nm and yields of > 90 % for hundreds of electrode pairs generated on a single substrate are demonstrated. These large width electrode nanogaps represent the highest aspect ratio nanogaps (up to 108) fabricated to date. As a next step, arrays of Schottky nanodiodes are fabricated by deposition of a suitable semiconductor from solution into the nanogap structures. Of principal interest is the wide bandgap transparent semiconductor, zinc oxide (ZnO). Lateral ZnO Schottky diodes show outstanding characteristics, with on-off ratios of up to 106 and forward current values up to 10 mA for obtained upon combining a-Lith with low-temperature solution processing. These unique devices are further investigated for application in rectifier circuits, and in particular for potential use in radio frequency identification (RFID) tag technology. The ZnO diodes are found to surpass the 13.56 MHz frequency bernchmark used in commercial applications and approach the ultra-high frequency (UHF) band (hundreds of megahertz), outperforming current state of the art printed diodes. Solution processed fullerene (C60) is also shown to approach the UHF band in this co-planar device configuration, highlighting the viability of a-Lith for enabling large-area flexible radio frequency nanoelectronics. Finally, resistive switching memory device arrays based on a-Lith patterned nanogap aluminium symmetric electrodes are demonstrated for the first time. These devices are based either on empty aluminium nanogap electrodes, or with the gap filled with a solution-processed semiconductor, the latter being ZnO, the semiconducting polymer poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) or carbon nanotube/polyfluorene blends. The switching mechanism, retention time and switching speed are investigated and compared with published data. The fabrication of arrays of these devices illustrates the potential of a-Lith as a simple technique for the realisation of large-area high-density memory applications.Open Acces

    Design of a Low-Cost Passive UHF RFID tag in 0.18um CMOS technology

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    The work addresses the design of a passive UHF Radio-Frequency Identification (RFID) tag. In order to realize a product able to be competitive in the RFID expanding market, a cost reduction policy has been applied in the design: a general purpose digital technology has been employed, resorting to specific techniques in order to overcome the limitations due to the lack of process options. Such solutions are accurately described, and every block composing the transponder analog frontend is analyzed, highlighting advantages and disadvantages of the proposed architectures with respect to the ones present in literature. The circuits theory is validated through simulations and experimental data.Il lavoro di tesi è imperniato sul progetto di un tag passivo per l'Identificazione a Radio-Frequenza (RFID) operante nelle bande UHF. Per il progetto è stata applicata una politica di riduzione dei costi, cosÏ da proporre un prodotto in grado di essere competitivo nel fiorente mercato dell'RFID: è stata scelta una tecnologia digitale general-purpose, e specifiche tecniche di progettazione sono state utilizzate per superare le limitazioni dovute alla scarsità di opzioni di processo. Le soluzioni adottate sono descritte accuratamente, ed è riportata l'analisi di ogni singolo blocco componente il frontend analogico, evidenziando vantaggi e svantaggi delle architetture proposte rispetto a quelle presenti in letteratura. La validità della teoria alla base dei circuiti è stata verificata tramite simulazioni e dati sperimentali

    Challenges and opportunities of introducing Internet of Things and Artificial Intelligence applications into Supply Chain Management

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    The study examines the challenges and opportunities of introducing Artificial Intelligence (AI) and the Internet of Things (IoT) into the Supply Chain Management (SCM). This research focuses on the Logistic Management. The central research question is “What are the key challenges and opportunities of introducing AI and IoT applications into the Supply Chain Management?” The goal of this research is to collect the most appropriate literature to help create a conceptual framework, which involves the integration of the IoT and AI applications into contemporary supply chain management with the emphasis on the logistics management. Additionally, the role of 5G Network is closely studied in order to indicate its capabilities and the processing capacity that it can provide to the AI and IoT operations. In addition, the semi-structured online interview with the top managers from several companies was conducted in order to identify the degree of readiness of the companies for the AI and IoT applications in SCM. From the retrieved results, the major challenges of integrating the IoT into SCM are the security and privacy issues, the sensitivity of the data and high costs of the implementation at an initial stage. Moreover, the research results have shown that the IoT applications can positively affect the SCM activities, in particular, the high visibility across the SC, an effective traceability and an automated data collection. Furthermore, the predictive analysis of AI programs can help the SCM to eliminate the potential errors and failures in the processes.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format
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