580 research outputs found

    Location-Aided Fast Distributed Consensus in Wireless Networks

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    Existing works on distributed consensus explore linear iterations based on reversible Markov chains, which contribute to the slow convergence of the algorithms. It has been observed that by overcoming the diffusive behavior of reversible chains, certain nonreversible chains lifted from reversible ones mix substantially faster than the original chains. In this paper, we investigate the idea of accelerating distributed consensus via lifting Markov chains, and propose a class of Location-Aided Distributed Averaging (LADA) algorithms for wireless networks, where nodes' coarse location information is used to construct nonreversible chains that facilitate distributed computing and cooperative processing. First, two general pseudo-algorithms are presented to illustrate the notion of distributed averaging through chain-lifting. These pseudo-algorithms are then respectively instantiated through one LADA algorithm on grid networks, and one on general wireless networks. For a k×kk\times k grid network, the proposed LADA algorithm achieves an ϵ\epsilon-averaging time of O(klog(ϵ1))O(k\log(\epsilon^{-1})). Based on this algorithm, in a wireless network with transmission range rr, an ϵ\epsilon-averaging time of O(r1log(ϵ1))O(r^{-1}\log(\epsilon^{-1})) can be attained through a centralized algorithm. Subsequently, we present a fully-distributed LADA algorithm for wireless networks, which utilizes only the direction information of neighbors to construct nonreversible chains. It is shown that this distributed LADA algorithm achieves the same scaling law in averaging time as the centralized scheme. Finally, we propose a cluster-based LADA (C-LADA) algorithm, which, requiring no central coordination, provides the additional benefit of reduced message complexity compared with the distributed LADA algorithm.Comment: 44 pages, 14 figures. Submitted to IEEE Transactions on Information Theor

    Near-Infrared High Efficiency Organic Dye Sensitized Solar Cells (DSCs) and Biological Fluorescent Imaging Dyes

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    With the energy consumption increase every year, the non-renewable energy sources such as fossil fuels, natural gas, and coal will not sustain forever. In this case, searching for a way to develop a renewable energy source is an emergency. For decades, dye-sensitized solar cells (DSCs) have received intensive attention due to their high power conversion efficiency and low material cost. This dissertation describes efforts to design and synthesize near-infrared organic dyes to apply to two systems: first, for use in the improvement of DSCs by the optimization of electron rich components such as ullazine and cross-conjugated -bridges to increase photon-to-electricity conversion and second, as a way to manipulate the UV-vis absorption and emission of the near-infrared organic dyes to use lower energy photons with wavelength ranges in the therapeutic window (700 nm-1000 nm)

    Railway service quality in northern Italy: A multilevel synthetic assessment:

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    In order to reasonably assess the railway service quality, a multilevel extensible assessment model is proposed based on the matter element theory and the extension theory. The proposed model is applied to a real case study of some railway lines. The matter element to assess the railway service quality is established on the basis of the characteristics of passenger transit which included 7 primary assessment indices and 26 senior assessment indices. The index weights are determined by the passengers who were interviewed on board during their journey. Railway service quality is assessed by the values of the correlation degree of the matter element with all the assessment grades. The multilevel extensible assessment method can fully reflect the distance between the overall railway service quality or one kind of service attribute and the assessment grades and then it can realize the continuous assessment. The method can provide not only the passengers' overall satisfaction degree on the railway service quality but also the passengers' satisfaction degree on one assessment index

    Suppression of photon shot noise dephasing in a tunable coupling superconducting qubit

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    We demonstrate the suppression of photon shot noise dephasing in a superconducting qubit by eliminating its dispersive coupling to the readout cavity. This is achieved in a tunable coupling qubit, where the qubit frequency and coupling rate can be controlled independently. We observe that the coherence time approaches twice the relaxation time and becomes less sensitive to thermal photon noise when the dispersive coupling rate is tuned from several MHz to 22 kHz. This work provides a promising building block in circuit quantum electrodynamics that can hold high coherence and be integrated into larger systems

    Effect of Investment in Environmental Protection on Green Development of Industrial Enterprises: Evidence from Central China

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    China\u27s industrialization and urbanization process is advancing rapidly. While using natural resources, the country also generates a large amount of waste, causing serious environmental pollution and affecting further development of human society. Expanding the scale of investment in environmental protection has gradually become an effective means to address the problem. China is continuously increasing investment in environmental protection, actively improving environmental conditions, and achieving the dual goals of promoting high-quality development and environmental protection. Six provinces in central China were taken as research objects and the regional differences in their investments in environmental protection were analyzed. A panel entropy weight model was used to calculate the green development level of industrial enterprises, and a panel regression model was employed to calculate the impact of investment in environmental protection on the degree of influence of the green development of industrial enterprises. Results show that the six provinces in central China have significant differences in their investment in industrial environmental pollution control. The unreasonable allocation of environmental protection investment funds has led to the insignificant improvement of environmental pollution caused by industrial enterprises in the six central provinces of investment in environmental protection. R&D expenditure of industrial enterprises, the total import, and export volume of foreign-invested enterprises, and the fixed asset investment of the entire society have a positive role in promoting the green development of industrial enterprises. The added value of the secondary industry has a significant negative effect on the green development of industrial enterprises. Conclusions can be used as a reference for encouraging industrial enterprises to increase investment in environmental protection and promote green development

    Topic-based integrator matching for pull request

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    Pull Request (PR) is the main method for code contributions from the external contributors in GitHub. PR review is an essential part of open source software developments to maintain the quality of software. Matching a new PR for an appropriate integrator will make the PR reviewing more effective. However, PR and integrator matching are now organized manually in GitHub. To make this process more efficient, we propose a Topic-based Integrator Matching Algorithm (TIMA) to predict highly relevant collaborators(the core developers) as the integrator to incoming PRs . TIMA takes full advantage of the textual semantics of PRs. To define the relationships between topics and collaborators, TIMA builds a relation matrix about topic and collaborators. According to the relevance between topics and collaborators, TIMA matches the suitable collaborators as the PR integrator
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