460 research outputs found

    Determining application-specific peak power and energy requirements for ultra-low-power processors

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    Many emerging applications such as IoT, wearables, implantables, and sensor networks are power- and energy-constrained. These applications rely on ultra-low-power processors that have rapidly become the most abundant type of processor manufactured today. In the ultra-low-power embedded systems used by these applications, peak power and energy requirements are the primary factors that determine critical system characteristics, such as size, weight, cost, and lifetime. While the power and energy requirements of these systems tend to be application-speci c, conventional techniques for rating peak power and energy cannot accurately bound the power and energy requirements of an application running on a processor, leading to overprovisioning that increases system size and weight. In this thesis, we present an automated technique that performs hardware-software co-analysis of the application and ultra-low-power processor in an embedded system to determine application-speci c peak power and energy requirements.Our technique provides more accurate, tighter bounds than conventional techniques for determining peak power and energy requirements, reporting 15% lower peak power and 17% lower peak energy, on average, than a conventional approach based on pro ling and guardbanding. Compared to an aggressive stressmark-based approach, our technique reports power and energy bounds that are 26% and 26% lower, respectively, on average. Also, unlike conventional approaches, our technique reports guaranteed bounds on peak power and energy independent of an application's input set. Tighter bounds on peak power and energy can be exploited to reduce system size, weight, and cost

    Watermarking protocol of secure verification

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    The secure verification is important for watermarking protocols. A malicious arbitrator is able to remove an original watermark from an unauthorized copy of the digital content as a result of a security breach in the phase of arbitration and resell multiple copies of it with impunity. We propose a novel buyer-seller watermarking protocol of secure verification. In this scheme, a seller permutes an original watermark provided by a trusted Watermarking Certification Authority (WCA) and embeds it into digital content in an encrypted domain. In case an unauthorized copy is found, the seller can recover the original watermark from the watermark extracted from the copy and sends it to an arbitrator. Without the knowledge of permutations applied by the seller, the arbitrator is unable to remove the permuted watermark from the digital content. Hence, verification is secured. As an additional advantage of the proposed protocol, arbitration can be conducted without the need for the cooperation of the WCA or the buyer

    Compact hollow waveguide mid-infrared gas sensor for simultaneous measurements of ambient CO2 and water vapor

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    A compact, sensitive and stable hollow waveguide (HWG) mid-infrared gas sensor, based on gas absorption lines using wavelength modulation spectroscopy with a second harmonic (WMS-2f) detection scheme, was developed for simultaneous measurements of ambient CO 2 and water vapor. Optimization of the laser modulation parameters and pressure parameter in the HWG are performed to improve the strength of the WMS-2f signal and hence the detection limit, where 14.5-time for CO 2 and 8.5-time for water vapor improvement in system detection limit is achieved compared to those working at 1 atm. The stability of the sensor has been improved significantly by optimizing environmental disturbances, incoupling alignment of the HWG and laser scanning frequency. An Allan variance analysis shows detection limit of the developed sensor of ~3 ppmv for CO 2 and 0.018% for water vapor, which correspond to an absorbance of 2.4 Ă— 10 -5 and 2.7 Ă— 10 -5 , with a stability time of 160 s, respectively. Ambient CO 2 and water vapor measurement have been performed in two days in winter and spring separately. The measurement precision is further improved by applying a Kalman adaptive filter. The HWG gas sensor demonstrates the ability in environmental monitoring and the potential to be used in other areas, such as industrial production and biomedical diagnosis

    Numerical analysis of the slub yarn breaking strength using finite element method

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    The numerical analysis of the slub yarn breaking strength has been made by using the finite element method (FEM). The slub yarn has been considered as skeletal structures since the yarn longitudinal length is much larger than its horizontal cross-section. Then, the accuracy of the proposed FEM model in calculating the slub yarn breaking strength has been validated by comparing the calculated results with the experimental data. This model can be used to calculate the slub yarn breaking strength normally and provides a theoretical support for product design

    A Novel Method of Sentence Ordering Based on Support Vector Machine

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    PACLIC 23 / City University of Hong Kong / 3-5 December 200

    Influence of light coupling configuration and alignment on the stability of HWG-based gas sensor system for real-time detection of exhaled carbon dioxide

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    A mid-infrared tunable diode laser absorption spectroscopy (TDLAS) gas sensor based on hollow waveguide (HWG) gas cell for real-time exhaled carbon dioxide (eCO2) detection is reported. A 2.73 ÎĽm distributed feedback (DFB) laser was used to target a strong CO2 absorption line, and wavelength modulation spectroscopy (WMS) with the second harmonic (WMS-2.) was used to retrieve the CO2 concentration with high sensitivity. The influence of different parameters, including coupling configuration of HWG, laser-to-HWG and HWG-to-detector coupling alignment on the stability of the HWG sensor is systematically studied. The HWG eCO2 sensor showed a fast response time of 2.7s, detection limit of 17 ppmv, and measurement precision of 20.9 ppmv with a 0.54 s temporal resolution. The eCO2 concentrations changed in breath cycles were measured in real time. The Allan variance indicated that the detection limit can reach 1.7 ppmv, corresponding to a detection sensitivity of 1.3(215)10-8 cm-1Hz-1/2, as the integration time increases to 26 s. This work demonstrates the performance characteristics and merits of HWG eCO2 sensor for exhaled breath analysis and potential detection for other exhaled gases

    A Study of Test Suite Reduction Based on Ant Lion Optimizer

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    The development of smart meters to Internet of Things is the infrastructure for the Internet to carry out user electricity management and enhance user experience with electricity. As the iteration of smart home service system based on smart meters continues to accelerate, the development process is becoming more and more demanding for software testing. Test suite reduction is one of the common methods to improve the efficiency of software testing. In this paper, we proposed an optimization algorithm based on the Ant Lion Optimizer applied to test suite reduction problem of smart IoT meters. The algorithm improved the traditional Ant Lion Optimizer by converting the smart IoT meter test suite reduction problem into a binary coverage problem and combining the Greedy Algorithm to obtain the optimal test case subset. The experimental results showed that the algorithm based on Ant Lion Optimizer performed better on the test suite reduction problems compared to similar algorithms

    Gene expression profile indicates involvement of NO in Camellia sinensis pollen tube growth at low temperature

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    DEGs identified from the comparison between control (CsPT-CK) and 4 °C-treated (CsPT-LT) pollen tbues. All of the samples were replicated three times. CK and LT FPKM: fragments per kb per million reads for each unigene in the CK and LT libraries, respectively. The log2Ratio (LT/CK): ratio between the FPKM of LT and CK. The absolute values of log2Ratio > 1 and probability > 0.7 were used as threshold for assigning significance. Annotation of DEGs against NR, NT, Swiss-Prot protein, KEGG, COG and GO were all reported in the tables. “-”: no hit. (XLS 381 kb

    Curcumin-loaded nanostructured lipid carrier induced apoptosis in human HepG2 cells through activation of DR5/caspases-mediated extrinsic apoptosis pathway

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    Curcumin is a lipophilic anti-cancer compound extracted from turmeric. Our previous study demonstrated that the curcumin-loaded nanostructured lipid carrier (Cur-NLC) exhibits superior anti-cancer activity in inhibiting proliferation as well as inducing apoptosis of human HepG2 cells compared to native curcumin. This study aims to unveil the mechanisms underlying the pro-apoptotic effect of Cur-NLC on HepG2 cells. Evidence indicates that low expression of death receptors (DRs) on cancer cell membranes leads to attenuated apoptosis signaling. This study showed that Cur-NLC significantly increased total expression of DR5 protein while simultaneously upregulated cell membrane expression of DR5. Cur-NLC significantly increased caspase-8 and caspase-3 activities, accompanied by increased apoptosis. Furthermore, enhanced apoptosis was inhibited in the presence of a pan-caspase inhibitor, Z-VAD-FMK. Therefore, Cur-NLC induced activation of the extrinsic apoptosis pathway via modulating the DR5/caspase-8/-3 mediated apoptosis pathway in HepG2 cells, suggesting that Cur-NLC is a promising therapeutic agent or supplement for the treatment of hepatocellular carcinoma
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