1,440 research outputs found

    Fluctuation-enhanced sensing

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    We present a short survey on fluctuation-enhanced gas sensing. We compare some of its main characteristics with those of classical sensing. We address the problem of linear response, information channel capacity, missed alarms and false alarms.Comment: Keynote Talk at SPIE's 4th international symposium on Fluctuations and Noise, Conference Noise and Fluctuations in Circuits, Devices and Materials, Florence, Italy, May 20-24, 200

    Oral treatment with herbal formula B307 alleviates skeletal muscle atrophy from hind-limb unloading

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    PosterINTRODUCTION: Muscle atrophy can result from physical inactivity, chronic bedrest, and ageing. Traditional Chinese herbal formula B307 is a health supplement with multiple potential protective functions of organs. We investigated the effects of herbal formula B307 on muscle atrophy using the hind-limb unloading (HU) model in mice …published_or_final_versio

    LED Traffic Light as Communication Device

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    The visible light from an LED (light emitting diode) traffic light can be modulated and encoded with information. Hence, it can be used for the broadcasting of audio messages or any traffic or road information. Essentially all LED traffic lights can be used as communications devices. The paper focuses on the description of an audio information system made up of high brightness, visible light emitting diodes (LEDs) in which one or more LEDs are modulated and encoded with audio messages. The system also comprises a receiver combined with a speaker which is located at a distance from the LED traffic light. The receiver is designed to demodulate the optically transmitted audio information and broadcast the messages with the speaker. The optical link employs intensity modulation with direct detection. The audio information system implemented on an LED traffic light can provide the function of open space, wireless broadcasting of audio messages.published_or_final_versio

    LED wireless

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    High-brightness light-emitting diodes (LEDs) are getting more popular and are opening up a number of new applications. In this paper, the novel idea based on the fast switching of LEDs and the modulation of visible light is developed into a new kind of information system. A visible-LED audio system that makes use of visual-light rays to transmit audio messages to a remotely located receiver is described. Such a system made up of high-brightness visible LEDs can provide the function of open space, wireless broadcasting of audio signals. It can be used as an information beacon for short-distance communication.published_or_final_versio

    Multi-megahertz IPT systems for biomedical devices applications

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    This paper investigates the main design constraints for the optimisation of an inductive power transfer (IPT) link for recharging implantable medical devices [1], and presents the potential advantages of operating in the multi-MHz range for such applications. The design proposed in this paper offers a fast charging solution, allowing patients to recharge their active medical implants every 4-5 years for 40% of its battery capability. The main challenge consists of obtaining good coupling and effective Q factor of the receiver coil, while minimizing the overall increase in size of the medical implant. Analysis obtained through electromagnetic simulations with CST Studio Suite for a 13.56 MHz, 1 W system suggests that it is possible to achieve a relatively high theoretical link efficiency of 66%, while keeping surface temperature increases and specific absorption rate (SAR) within the limits established in EN 45502 [2] and ICNIRP 1998 [3]. The experimental results show two feasible systems with different separation distances between the device's metallic case and the receiver coil, achieving transfer efficiencies [11] of 41% and 53% for separations of 1 mm and 7 mm, respectively

    Developing an interactive game platform to promote learning and teamwork on mobile devices: an experience report

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    In the past few Years, many new development toolkits such as the Nebula2 and/or mobile technologies including the WiFi or mobileTV have opened up exciting learning opportunities on mobile devices. On top of it, new technologies continue to fuel the rapid growth of newly merged fields of research like the edutainment for educational entertainment. In a recent teaching development project, we have developed an interactive game platform to facilitate learning and more importantly the spirit of teamwork for collaborative problem-solving on desktop and pocket PCs. With the great challenges imposed by globalization, we strongly believe that learning to collaboratively analyze and then apply the "appropriate" knowledge to solve a specific problem is always the key to success. In this paper, we discuss about an on-going work, and share our relevant experience in system development. Furthermore, evaluation strategies will be thoroughly examined. After all, our work shed light on many interesting directions for future exploration. © 2008 IEEE.published_or_final_versio

    Implicit person theories and change in teacher evaluation: A longitudinal field study

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    Adopting a longitudinal field study, this paper investigates whether entity theorists (students who believe human attributes are fixed) are less likely than incremental theorists (students who believe human attributes are malleable) to change their evaluations of a teacher in accordance with his behavioral changes. An instructor exhibited some forgetful behaviors in the first half of a course, and ceased doing so in the second half. Consistent with our hypothesis, incremental theorists adjusted their perceptions of the instructor. They rated him as less forgetful accordingly at the end of the course than at the middle. Entity theorists, however, did not show this change. With improved ecological validity, this study extends previous laboratory studies to teacher evaluation. © 2010 Copyright the Authors. Journal compilation © 2010 Wiley Periodicals, Inc.postprin

    A 13.56 MHz bidirectional IPT system with wirelessly synchronised transceivers for ultra-low coupling operation

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    This paper presents a high-frequency inductive power transfer (HF-IPT) system with bidirectional capability employing a new wireless synchronisation method. Synchronisation is achieved by transmitting a reference ultra high frequency tone (433.92 MHz) that is stepped down to 13.56 MHz in each transceiver. This allows the operating frequency to be locked across the two sides of the system. Afterwards, a phase search is performed looking for maximum power throughput, determining the phase at the point of resonance (i.e., no reflected reactances). The experimental implementation is achieved with two back-to-back Class EF coil-drivers driven by independent synchronisation circuits. In the experimental setup a constant input voltage is set for each of the two coil-drivers by implementing a source-sink configuration, emulating a bidirectional DC-DC conversion stage at each side. Experimental results show successful transceiver synchronisation, and 4 W were transferred from one end to the other and conversely at an ultra-low coupling of 1.6%. This proves that the combination of the load-independent Class EF transceivers and the synchronisation technique introduced herein is suitable for applications that require large tolerance to misalignment and air gaps larger than one coil diameter, such as in micro e-mobility

    Characterisation of high frequency inductive power transfer receivers using pattern recognition on the transmit side waveforms

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    This paper demonstrates the characterisation of inductively coupled receivers for high frequency inductive power transfer (HF-IPT) systems using pattern recognition on the inverter waveforms at the transmit side. The impedance reflected by the candidate receivers to the transmit coil was estimated using a model programmed to associate the experimental drain-voltage waveforms of the inverter when it drives a receiver under test to those when driving known loads. The necessity of employing this technique is due to the difficulty of accurately measuring current and voltage across the coil given the parasitic effects of probing and the precise skewing required to measure an impedance, especially at high Q-factor. The proposed technique is convenient for characterising and comparing the impedance reflected by candidate receivers for a particular application where there is a choice to be made with respect to the rectifier topologies and semiconductor technologies. Experimental results, using a 13.56 MHz 100 W inductive power transfer system, were obtained for a full-wave Class D rectifier using silicon (Si) and silicon carbide (SiC) Schottky diodes, and two Class E rectifiers using SiC diodes
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