78 research outputs found

    Power-Rate-Distortion Analysis for Wireless Video Communication under Energy Constraints

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    Digital Object Identifier 10.1109/TCSVT.2005.846433Mobile devices performing video coding and streaming over wireless and pervasive communication networks are limited in energy supply. To prolong the operational lifetime of these devices, an embedded video encoding system should be able to adjust its computational complexity and energy consumption as demanded by the situation and its environment. To analyze, control, and optimize the rate-distortion (R-D) behavior of the wireless video communication system under the energy constraint, we develop a power-rate-distortion (PR-D) analysis framework, which extends the traditional R-D analysis by including another dimension, the power consumption. Specifically, in this paper, we analyze the encoding mechanism of typical video coding systems, and develop a parametric video encoding architecture which is fully scalable in computational complexity. Using dynamic voltage scaling (DVS), an energy consumption management technology recently developed in CMOS circuits design, the complexity scalability can be translated into the energy consumption scalability of the video encoder. We investigate the R-D behavior of the complexity control parameters and establish an analytic P-R-D model. Both theoretically and experimentally, we show that, using this P-R-D model, the video coding system is able to automatically adjust its complexity control parameters to match the available energy supply of the mobile device while maximizing the picture quality. The P-RD model provides a theoretical guideline for system design and performance optimization in mobile video communication under energy constraints

    Isomeric Effects of Solution Processed Ladderâ Type Nonâ Fullerene Electron Acceptors

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138922/1/solr201700107_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138922/2/solr201700107-sup-0001-SuppData-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138922/3/solr201700107.pd

    Smart Grid Project Benefit Evaluation Based on a Hybrid Intelligent Model

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    With the accelerated development of smart cities, the construction and development of smart grids have an increasing impact on the safe and stable operation of power systems. The benefit evaluation of smart grids can find out the problems of smart grids more comprehensively, which is of great practical significance for the further development of smart cities. In order to ensure accuracy and real-time evaluation, this paper proposes a new hybrid intelligent evaluation model using an improved technique for order preference by similarity to an ideal solution (TOPSIS) and long–short-term memory (LSTM) optimized by a modified sparrow search algorithm (MSSA). First, a set of smart grid benefit evaluation index systems is established in the context of considering smart city development. Then, aiming at the reverse order problem existing in TOPSIS, an improved evaluation model with entropy weight and modified TOPSIS is established. Finally, an intelligent evaluation model based on LSTM with MSSA optimization is designed. The example analysis verifies the accuracy of the model proposed, points out the important factors affecting the benefits of smart grids, and provides a new idea to achieve effective evaluation and rapid prediction, which can help to improve the benefit level of smart grids

    Determination of Pressure Drop Correlation for Air Flow through Packed Bed of Sinter Particles in Terms of Euler Number

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    In order to clearly understand the air flow resistance characteristics in vertical tanks for sinter waste heat recovery in the steel industry, experimental research on the air flow pressure drop (FPD) performance in a sinter bed layer (BL) was conducted. Based on a self-made experimental device, the measurement values of air FPD for different experimental conditions were determined firstly, and then the concept of Euler number (Eu) in heat exchangers was introduced into the study of air FPD in BL; the change rules of Eu under different particle diameters were analyzed. Finally, the air FPD correlation in sinter BL was obtained and described in the form of Eu, and the error analysis of obtained air FPD correlation was performed. The results show that, the air FPD increases as a second power relationship with the increase in air superficial velocity when the particle diameter is constant. The decrease amplitude of Eu gradually dwindles when increasing the Reynolds number (Re), and the decrease in the Eu shows a reciprocal relationship with the Re. As the bed geometry factor increases, the FPD coefficient, A, decreases as an exponential relationship, while the FPD coefficient, B, increases as a first power relationship. The obtained air FPD correlation in the form of Eu in the experiment is well compatible with the measurement values, and the mean deviation of obtained correlation is 4.67%, showing good originality

    Diagnostic Accuracy of Procalcitonin Compared to C-Reactive Protein and Interleukin 6 in Recognizing Gram-Negative Bloodstream Infection: A Meta-Analytic Study

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    Objective. Gram-negative bloodstream infections (GNBSIs), especially those caused by antibiotic-resistant species, have become a public health challenge. Procalcitonin (PCT) showed promising potential in early diagnosis of GNBSI; however, little was known about its performance under different clinical settings. We here systematically assessed the diagnostic accuracy of PCT in recognizing GNBSI and made direct comparisons with C-reactive protein (CRP) and interleukin 6 (IL-6). Methods. PubMed, Embase, ISI Web of Knowledge, and Scopus were searched from inception to March 15th, 2019. Area under the summary receiver operating characteristic curve (AUC), pooled sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated. Hierarchical summary receiver operating characteristic (HSROC) model was used for the investigation of heterogeneity and for comparisons between markers. Results. 25 studies incorporating 50933 suspected BSI episodes were included. Pooled sensitivity and specificity for PCT were 0.71 and 0.76, respectively. The overall AUC was 0.80. The lowest AUCs were found in patients with febrile neutropenia (0.69) and hematological malignancy (0.69). The highest AUC was found in groups using electrochemiluminescence immunoassay (0.87). In direct comparisons, PCT showed better overall performance than CRP with the AUC being 0.85 (95% CI 0.81–0.87) for PCT and 0.78 (95% CI 0.74–0.81) for CRP, but the relative DORs varied with thresholds between PCT and CRP (p<0.001). No significant difference was found either in threshold (p=0.654) or in accuracy (p=0.480) between PCT and IL-6 in diagnosing GNBSI. Conclusions. PCT was helpful in recognizing GNBSI, but the test results should be interpreted carefully with knowledge of patients’ medical condition and should not serve as the only criterion for GNBSI. Further prospective studies are warranted for comparisons between different clinical settings

    In Situ Deposition of Gold Nanoparticles and L-Cysteine on Screen-Printed Carbon Electrode for Rapid Electrochemical Determination of As(III) in Water and Tea

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    In this study, a screen-printed carbon electrode (SPCE) based on in situ deposition modification was developed for the sensitive, rapid, easy and convenient determination of As(III) in water and tea by linear sweep anodic stripping voltammetry (LSASV). The screen-printed carbon electrodes were placed in a solution consisting of As(III) solution, chlorauric acid and L-cysteine. Under certain electrical potential, the chloroauric acid was reduced to gold nanoparticles (AuNPs) on the SPCE. L-cysteine was self-assembled onto AuNPs and promoted the enrichment of As(III), thus enhancing the determination specificity and sensitivity of As(III). The method achieved a limit of determination (LOD) of 0.91 ppb (µg L−1), a linear range of 1~200 µg L−1, an inter-assay coefficient of variation of 5.3% and good specificity. The developed method was successfully applied to the determination of As(III) in tap water and tea samples, with a recovery rate of 93.8%~105.4%, and further validated by inductively coupled plasma mass spectrometry (ICP-MS). The developed method is rapid, convenient and accurate, holding great promise in the on-site determination of As(III) in tap water and tea leaves, and it can be extended to the detection of other samples
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