In the context of powering indoor sensor nodes from the ambient optical energy, an experimental test of lowarea photovoltaic (PV) cells under real indoor operating conditions for some weeks is proposed and carried out...
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ISBN:
(纸本)9798350369267;9798350369250
In the context of powering indoor sensor nodes from the ambient optical energy, an experimental test of lowarea photovoltaic (PV) cells under real indoor operating conditions for some weeks is proposed and carried out herein. The study involves PV cells of different technology (i.e., monocrystalline, amorphous, organic, and III- V type) and days with different weather (i.e., sunny, partly-cloudy, cloudy, and rainy). The experimental results show that, in a sunny day, the average (per day) power density can be up to 118 mu W/cm(2) for the monocrystalline technology. This corresponds, for an active area of 10 cm(2), to an average power of more than 1 mW, which is an acceptable value for a low-power sensor node. In a cloudy day, the average power density is around 25 mu W/cm(2) for the monocrystalline, provided that the room under test is at the top floors of the building. However, under only the effects of artificial lighting, the average power density is really low, to be precise: less than 2 mu W/cm(2) for the monocrystalline. This value increases up to 13 mu W/cm(2) for the III-V cell, but this is an expensive technology. Therefore, the energetic survival of an indoor low-cost sensor node needs to leverage the natural light.
This study proposed the application of microwave resonators embedded with carbon nanotube (CNT) sensing films fabricated using inkjet printing technology as gas sensors. The density and uniformity of CNTs dominated re...
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This study proposed the application of microwave resonators embedded with carbon nanotube (CNT) sensing films fabricated using inkjet printing technology as gas sensors. The density and uniformity of CNTs dominated resistance, which was related to inkjet printing droplet spacing (DS), layer numbers, and electrode patterns. Although the high-density resistive-type CNT (DS = 20 mu m and 20 layers) sensor with the regular electrode (RE) pattern had a lower response than the low-density CNT (DS = 30 mu m) sensor, its response presented a narrow repeatability distribution. The response of the high-density CNT sensor with interdigital electrode (IDE) pattern can be improved and was even higher than that of the low-density CNT sensor with the RE pattern. Based on the results of resistive-type sensors, the frequency responses of the CNT films with DS = 20 and 30 mu m, 20 layers, and the IDE pattern embedded into transmission-type resonators were studied. During NH3 absorption, the insertion and return losses of the resonator embedded with the sensing film with DS = 20 mu m and 20 layers increased, whereas those of the resonator embedded with the sensing film with DS = 30 mu m and 20 layers decreased. The resonator frequency of both films increased because the CNT resistance increased during NH3 absorption. These results indicated that the frequency response of the microwave sensors was related to the resistance of CNT films. A transmission-type microwave resonator can provide multidimensional frequency responses and high repeatability and has the potential for integration with the IoT and RFID for wireless gas-sensing applications.
With the development of neural network technology, Spiking Neural Networks (SNNs) have shown great potential in edge computing and embedded systems due to their biologically inspired and low-power characteristics. Thi...
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This senior thesis develops a real-time handwritten digit identification system using a Raspberry Pi 3B+ with a camera module, leveraging a lightweight CNN optimized with MNIST. The project highlights the effective im...
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embedded software commonly executes safety-critical tasks and thus is expected to be highly reliable, which calls for stronger quality assurance techniques. As a fault-based testing technique, mutation testing is wide...
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This study introduces a dynamic platform with a micro-electromechanical system (MEMS) microphone array for robust unmanned aerial vehicle (UAV) detection and tracking. Leveraging the compactness of MEMS technology, th...
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ISBN:
(纸本)9798350386851;9798350386844
This study introduces a dynamic platform with a micro-electromechanical system (MEMS) microphone array for robust unmanned aerial vehicle (UAV) detection and tracking. Leveraging the compactness of MEMS technology, the platform integrates microphones to capture UAV acoustic signatures using Direction of Arrival (DOA) and Beamforming technologies. Its adaptability optimizes surveillance coverage, surpassing the limitations of visual tracking in adverse conditions. This research details the design, calibration, and integration processes, validated through rigorous testing. This innovation improves real-time situational awareness, offering a promising solution for security and defense applications.
This study proposes a method that employs a renderer as a tool for environmental recognition. In the proposed system, features are extracted from sensors and cameras;the renderer represents scenes in a 3-D space to su...
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Robotic-based therapy is becoming a very popular treatment for the rehabilitation of hand function impairment as a consequence of strokes, due to the high-dimensional and less interpretable nature of superficial elect...
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ISBN:
(纸本)9798350378290;9798350378283
Robotic-based therapy is becoming a very popular treatment for the rehabilitation of hand function impairment as a consequence of strokes, due to the high-dimensional and less interpretable nature of superficial electromyography (sEMG) signals. In this context, feature engineering becomes particularly important to estimate the intention of upper limb movements by utilizing machine learning models, specially when a hardware embedded on-board implementation is expected, due to the strong computational, energy and latency constraints. Our work compares the performance achieved by implementing four state-of-the-art feature techniques (random forest, minimum redundancy maximum relevance (MRMR), Davies-Bouldin index, and t-tests), when these are evaluated on a sEMG dataset intended for training hand gesture classifiers. The results of three different machine learning algorithms (neuronal networks, k-nearest neighbors and bagged forest) are used as a reference to validate the analysis. This ongoing research has revealed valuable information on the potential and constraints of these 4 feature generation methods for real gesture recognition embeddedapplications.
Seeking to reduce the computational effort to model the intrinsically complex active distribution networks (ADNs), this article proposes a new realistic approach to develop a real-time reduced steady-state model of an...
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Seeking to reduce the computational effort to model the intrinsically complex active distribution networks (ADNs), this article proposes a new realistic approach to develop a real-time reduced steady-state model of an ADN using synchrophasor measurements. Such models facilitate much needed co-simulation of the bulk power system (BPS) and multiple ADNs for grid support applications. With the advent of distribution-level phasor measurement units (D-PMUs), the synchrophasor data are employed to derive the reduced model parameters in real-time and track the time-varying ADN operating point. The proposed approach develops a general three-phase four-wire reduced model which can replace any arbitrary feeder configuration confined within D-PMUs. The explicit modelling of neutral-wire under different neutral-grounding conditions results in accurate representation of any unbalanced and complex feeder segment, containing transformers, distributed generators, loads and n-phase laterals. Further, the reduced model is modified to account for embedded distributed generation, which is useful for effective estimation of grid support capability at the transmission-distribution interface. The proposed reduced model has been extensively validated on the highly unbalanced ieee-13 bus feeder system for various test cases, including high penetration of locally-controlled photovoltaic inverters. DIgSILENT PowerFactory MATLAB co-simulation has been used as the platform to establish the model accuracy.
This paper proposes an embedded system for efficient, real-time brain stroke prediction. While many machine learning techniques achieve high accuracy, their implementation on embedded platforms remains challenging. Th...
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