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This work investigates a 5.5–7.5-GHz band-configurable duty-cycled wake-up receiver (WuRX) fully implemented in a 45-nm radio-frequency (RF) silicon-on-insulator (SOI) complementary-metal-oxide-semiconductor (CMOS) technology. Based on an uncertain intermediate frequency (IF) super-heterodyne receiver (RX) topology, the WuRX analogue front-end (AFE) incorporates a 5.5–7.5-GHz band-tunable low-power low-noise amplifier, a low-power Gilbert mixer, a digitally controlled oscillator (DCO), a 100-MHz IF band-pass filter (BPF), an envelope detector, a comparator, a pulse generator and a current reference. By application of duty cycling with a low duty cycle below 1%, the power consumption of the AFE was significantly reduced. In addition, the on-chip digital bank-end consists of a frequency divider, a phase corrector, a 31-bit correlator and a serial peripheral interface. A proof-of-concept WuRX circuit occupying an area of 1200 μm by 900 μm has been fabricated in a GlobalFoundries 45-nm RF-SOI CMOS technology. Measurement results show that at a data rate of 64 bps, the entire WuRX consumes only 2.3 μW. Tested at 8 operation bands covering 5.5–7.7 GHz, the WuRX has a measured sensitivity between −67.5 dBm and −72.4 dBm at a wake-up error rate of 10−3. With the sensitivity unchanged, the data rate of the WuRX can be scaled up to 8.2 kbps. To the authors' best knowledge, this work offers the largest RF bandwidth from 5.5 to 7.5 GHz, the most operation channels (≥8) and the fastest settling time (<115 ns) among the WuRXs reported to date.

The integration of wireless communication, e.g., in real- or quasi-real-time applications, is related to many challenges such as energy consumption, communication range, quality of service, and reliability. The improvement of wireless sensor networks (WSN) performance starts by enhancing the capabilities of each sensor node. To minimize latencies without increasing energy consumption, wake-up receiver (WuRx) nodes have been introduced in recent works since they can be always-on or power-gated with short latencies by a power consumption in the range of some microwatts. Compared to standard receiver technologies, they are usually characterized by drawbacks in terms of sensitivity. To overcome the limitation of the sensitivity ofWuRxs, a design of a low noise amplifier (LNA) with several design specifications is required. The challenging task of the LNA design is to provide equitable trade-off performances such as gain, power consumption, the noise figure, stability, linearity, and impedance matching. The design of fast settling LNA for a duty-cycled WuRx front-end operating at a 868 MHz frequency band is investigated in this work. The paper details the trade-offs between design challenges and illustrates practical considerations for the simulation and implementation of a radio frequency (RF) circuit. The implemented LNA competes with many commercialized designs where it reaches single-stage 12 dB gain at a 1.8 V voltage supply and consumes only a 1.6 mA current. The obtained results could be made tunable by working with off-the-shelf components for different wake-up based application exigencies.

The focus of this research was the spontaneous magnetic alignment responses of animals. We show that snapping turtles (Chelydra serpentina) and crayfish (Cambarus sciotensis) spontaneously align their body axes relative to the magnetic field. In snapping turtles, this response is sensitive to low-level radio frequency fields, consistent with a mechanism involving a light-dependent radical pair mechanism. Findings from the turtle experiments also suggest that the Earth's magnetic field plays an important role in encoding spatial information in novel surroundings, and may help to organize multiple locales into a 'mental map' of familiar space. Given the importance of magnetic input in many aspects of spatial behavior, another important finding was that magnetic alignment of yearling turtles was disrupted by high levels of maternally transferred mercury, an industrial waste product found at high levels in some fresh water ecosystems. In crayfish, we investigated the effects of ectosymbionts (Annelida: Branchiobdellida) on magnetic alignment responses. Interestingly, the response of crayfish to magnetic cues parallels the complex symbiotic interaction between crayfish and their ectosymbiotic worms, which changes from mutualistic to parasitic with increasing worm density. Our working hypothesis was that these changes in spatial behavior may increase or decrease contact to other crayfish, and therefore increase or decrease transmission rates. Next, to address the ontogeny of the SMA, we attempted to replicate an earlier study showing a possible magnetic alignment response in chicken embryos. Although chicken embryos did show non-random alignment, we were not able to find a magnetic effect. Alignment is also an important feature of animal constructions and is very likely to have fitness consequences, which we explored in woodpecker cavity alignments in a meta-analysis of available global data. The latitudinal and continental pattern in 23 species of woodpeckers suggests that an alignment response can have the proximate function to regulate microclimate in the cavity and therefore, presumably, optimize incubation temperatures and increase hatching success. Overall, the presented findings show how experimental and observational studies of spontaneous alignment behavior can provide insight into the ecology and sensory biology of a wide range of animals. / Ph. D.

Radio Frequency Identification (RFID) is a new technology which allows people to identify objects automatically but there is a suspicion that, if people are tracked, their privacy may be infringed. This raises questions about how far this technology is acceptable and how privacy should be protected. It is also initiated a discussion involving a wide range of technical, philosophical, political, social, cultural, and economical aspects. There is also a need to consider the ethical and theological perspectives. This dissertation takes all its relevant directions from a Judeo-Christian theological perspective. On one side the use of technology is considered, and on the other side the value of privacy, its infringements and protection are investigated. According to Jewish and Christian understanding human dignity has to be respected including the right to privacy. As a consequence of this RFID may only used for applications that do not infringe this right. This conclusion, however, is not limited to RFID; it will be relevant for other, future surveillance technologies as well. / Philosophy & Systematic Theology / M. Th. (Theological ethics)

This study investigated the factors, best practice, advantages and disadvantages that influence the use of radio frequency identification (RFID) self-help circulation services for service delivery by South African academic libraries with specific emphasis on the University of South Africa (Unisa) Library. Unisa Library Services is the only library service in South Africa that has implemented a fully-fledged RFID self-help circulation service. There must therefore be reasons why other libraries in South Africa have not implemented this type of service. Accordingly, a need was identified to investigate the aspects that should be considered before a library decides to implement such a circulation service. There was also a need to identify the factors, best practice, advantages and disadvantages that influence the use of RFID self-help circulation services. The study gives a brief overview of RFID technology and its use in libraries internationally with specific emphasis on its use for self-help circulation purposes. Through a literature study, certain factors, best practice, advantages and disadvantages that influence the use of RFID self-help circulation services were identified. The identified factors, best practice, advantages and disadvantages were subsequently used to compile questionnaires to obtain information from Unisa library users (students and staff). Only Unisa staff and students who were situated close to Unisa campuses with RFID self-help circulation services were included in the study. During the analysis of the data collected additional factors, best practice, advantages and disadvantages were identified. Recommendations were compiled regarding the factors, best practice, advantages and disadvantages that influence the use of RFID self-help circulation services. These recommendations are meant as a guide for South African libraries when making decisions on the possible implementation and use of RFID self-help circulation services. / Information Science / M.A. (Information Science)

Radio Frequency Identification (RFID) is a new technology which allows people to identify objects automatically but there is a suspicion that, if people are tracked, their privacy may be infringed. This raises questions about how far this technology is acceptable and how privacy should be protected. It is also initiated a discussion involving a wide range of technical, philosophical, political, social, cultural, and economical aspects. There is also a need to consider the ethical and theological perspectives. This dissertation takes all its relevant directions from a Judeo-Christian theological perspective. On one side the use of technology is considered, and on the other side the value of privacy, its infringements and protection are investigated. According to Jewish and Christian understanding human dignity has to be respected including the right to privacy. As a consequence of this RFID may only used for applications that do not infringe this right. This conclusion, however, is not limited to RFID; it will be relevant for other, future surveillance technologies as well. / Philosophy and Systematic Theology / M. Th. (Theological ethics)

A utilização de etiquetas RFID UHF passivas para localização indoor vem sendo amplamente estudada devido ao seu baixo custo. Porém ainda existe uma grande dificuldade em obter bons resultados, principalmente devido à variação de rádio frequência em ambientes que possuem materiais reflexivos, como por exemplo, metais e vidros. Esta pesquisa propõe uma arquitetura de localização para ambientes indoor utilizando etiquetas RFID UHF passivas e técnicas de mineração de dados. Com a aplicação da arquitetura em ambiente real foi possível identificar a posição exata de objetos com a precisão de aproximadamente cinco centímetros e em tempo real. A arquitetura se demonstrou uma eficiente alternativa para implantação de sistemas de localização indoor, além de apresentar uma técnica de derivação de atributos diretos que contribui efetivamente para os resultados finais. / The use of passive UHF RFID tags for indoor location has been widely studied due to its low cost. However, there is still a great difficulty to reach good results, mainly due the radio frequency variation in environments that have materials with reflective surfaces, such as metal and glass. This research proposes a localization architecture for indoor environments using passive UHF RFID tags and data mining techniques. With the application of the architecture in real environment, it was possible to identify the exact position of objects with the precision of approximately five centimeters and in real time. The architecture has demonstrated an efficient alternative for the implantation of indoor localization systems, besides presenting a derivation technique of direct attributes that contributes effectively to the final results.