5,636 research outputs found

    Research on Efficiency of Collaborative Allocation System of Emergency Material Based on Synergetic Theory

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    AbstractEmergencies increasingly become so comprehensive covering large areas and derivative that a single organization can not meet the requirement of emergency disposition. Therefore, collaborative allocation of emergency material involving multi-organizations becomes one of the key content of emergency management. The collaborative allocation system of emergency material has the characteristics of complex system. Based on synergetic theory of systems engineering and the actual problem of low efficiency of collaborative allocation of emergency material in our country, the key factors influencing efficiency improvement are analyzed in respect of people, organization, material, information, technology and strategy. By adopting and improving QSIM (qualitative simulation method), the inner action mechanism is studied and the conclusion is that the responsibility and authority definition, the coordination ability of decision-makers and information transmission efficiency are the most important factors for the efficiency of collaborative allocation. The measures set forth in this paper are for the reference of relevant decision-makers and we hope it can be helpful for their decision making

    Adversarial Attack and Defense on Graph Data: A Survey

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    Deep neural networks (DNNs) have been widely applied to various applications including image classification, text generation, audio recognition, and graph data analysis. However, recent studies have shown that DNNs are vulnerable to adversarial attacks. Though there are several works studying adversarial attack and defense strategies on domains such as images and natural language processing, it is still difficult to directly transfer the learned knowledge to graph structure data due to its representation challenges. Given the importance of graph analysis, an increasing number of works start to analyze the robustness of machine learning models on graph data. Nevertheless, current studies considering adversarial behaviors on graph data usually focus on specific types of attacks with certain assumptions. In addition, each work proposes its own mathematical formulation which makes the comparison among different methods difficult. Therefore, in this paper, we aim to survey existing adversarial learning strategies on graph data and first provide a unified formulation for adversarial learning on graph data which covers most adversarial learning studies on graph. Moreover, we also compare different attacks and defenses on graph data and discuss their corresponding contributions and limitations. In this work, we systemically organize the considered works based on the features of each topic. This survey not only serves as a reference for the research community, but also brings a clear image researchers outside this research domain. Besides, we also create an online resource and keep updating the relevant papers during the last two years. More details of the comparisons of various studies based on this survey are open-sourced at https://github.com/YingtongDou/graph-adversarial-learning-literature.Comment: In submission to Journal. For more open-source and up-to-date information, please check our Github repository: https://github.com/YingtongDou/graph-adversarial-learning-literatur

    In-plane graphene/boron-nitride heterostructures as an efficient metal-free electrocatalyst for the oxygen reduction reaction

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    Exploiting metal-free catalysts for the oxygen reduction reaction (ORR) and understanding their catalytic mechanisms are vital for the development of fuel cells (FCs). Our study has demonstrated that in-plane heterostructures of graphene and boron nitride (G/BN) can serve as an efficient metal-free catalyst for the ORR, in which the C-N interfaces of G/BN heterostructures act as reactive sites. The formation of water at the heterointerface is both energetically and kinetically favorable via a four-electron pathway. Moreover, the water formed can be easily released from the heterointerface, and the catalytically active sites can be regenerated for the next cycle. Since G/BN heterostructures with controlled domain sizes have been successfully synthesized in recent reports (e.g. Nat. Nanotechnol., 2013, 8, 119), our results highlight the great potential of such heterostructures as a promising metal-free catalyst for the ORR in FCs

    Prosthesis replacement in Mason III radial head fractures: A meta-analysis

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    AbstractIntroductionThis present study was to evaluate the clinical efficacy of prosthesis replacement (PR) for patients with Mason III radial head fractures (RHF) compared with open reduction and internal fixation (ORIF).MethodsWe retrieved the relevant trials up to September 2013 from several public databases, mainly including PubMed, Embase, Springer, Elsevier Science Direct, Cochrane Library, Google scholar, CNKI and Wanfang database. Weighted mean difference (WMD) or odds ratio (OR) and their 95% confidence intervals (CI) were calculated to compare the clinical outcomes between PR and ORIF.ResultsA total of 9 studies including 365 patients with Mason III RHF (169 patients treated with PR and 196 patients treated with ORIF) were reanalyzed in the meta-analysis. The results showed that the patients with Mason III RHF receiving PR, compared with the ORIF ones, had a significantly higher percentage of postoperative excellent and good rate (OR=3.48, 95% CI=1.98 to 6.11, P<0.0001), better Broberg and Morrey elbow scores (WMD=9.79, 95% CI=4.22 to 15.36, P=0.0006) and significantly lower postoperative complications (OR=0.33, 95% CI=0.16 to 0.69, P=0.003).ConclusionsAlthough the results of this study supported the use of PR in the treatment of Mason III RHF in Chinese population with short-term outcomes, the evidences are of low quality and further studies were required for confirming these results in the longer term on other populations.Level of evidenceLevel III. Low power meta-analysis

    Herb-resistant UPEC strains have different biofilm formation abilities and different expression of certain biofilm related genes

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    Background: The mechanisms and patterns of drug resistances of E. coli strains that cause uncomplicated urinary tract infections (UTIs) vary considerably. The emerging herbresistance of uropathogenic Escherichia coli (UPEC) has been a serious health problem, yet with unknown underlying mechanisms.Methods: To explore the potential herb-resistance mechanisms of E. coli strains that cause uncomplicated UTIs, three clinically isolated herb-resistant UPEC strains (1351, 4996, 5028) were analyzed for their abilities to form biofilms and the expressions of the pga ABCD and luxS genes.Results: We found that the expression of pgaA and pgaB are very different between 1351 and 5028, and the loss-offunction of luxS in 4996 has impact on biofilm formation.Conclusions: 1. Herb-resistance of the strains is related to their abilities of biofilm formation. 2. Biofilm formation capabilities of herb-resistant strains show different responses to the presence of glucose. 3. luxS encoded AI-2 is not essential for biofilm formation in this strain but may help with more biofilm formation.Keywords: Herb-resistance; Biofilm formation; Uropathogenic Escherichia coli (UPEC); pga ABCD; lux

    Cavity-Heisenberg spin chain quantum battery

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    We propose a cavity-Heisenberg spin chain (CHS) quantum battery (QB) with the long-range interactions and investigate its charging process. The performance of the CHS QB is substantially improved compared to the Heisenberg spin chain (HS) QB. When the number of spins N1N \gg 1, the quantum advantage α\alpha of the QB's maximum charging power can be obtained, which approximately satisfies a superlinear scaling relation PmaxNαP_{max} \propto N^{\alpha}. For the CHS QB, α\alpha can reach and even exceed 1.51.5, while the HS QB can only reach about α=0.75\alpha=0.75. We find that the maximum stored energy of the CHS QB has a critical phenomenon. By analyzing the Wigner function, von Neumann entropy, and logarithmic negativity, we demonstrate that entanglement can be a necessary ingredient for QB to store more energy, but not sufficient

    First Total Synthesis of a Naturally Occurring Iodinated 5′-Deoxyxylofuranosyl Marine Nucleoside

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    4-Amino-7-(5′-deoxy-β-D-xylofuranosyl)-5-iodo-pyrrolo[2,3-d]pyrimidine 1, an unusual naturally occurring marine nucleoside isolated from an ascidan, Diplosoma sp., was synthesized from D-xylose in seven steps with 28% overall yield on 10 g scale. The key step was Vorbrüggen glycosylation of 5-iodo-pyrrolo[2,3-d]pyrimidine with 5-deoxy-1,2-O-diacetyl-3-O-benzoyl-D-xylofuranose. Its absolute configuration was confirmed
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