A Topology Visualization Early Warning Distribution Algorithm for Large-Scale Network Security Incidents

It is of great significance to research the early warning system for large-scale network security incidents. It can improve the network system’s emergency response capabilities, alleviate the cyber attacks’ damage, and strengthen the system’s counterattack ability. A comprehensive early warning system is presented in this paper, which combines active measurement and anomaly detection. The key visualization algorithm and technology of the system are mainly discussed. The large-scale network system’s plane visualization is realized based on the divide and conquer thought. First, the topology of the large-scale network is divided into some small-scale networks by the MLkP/CR algorithm. Second, the sub graph plane visualization algorithm is applied to each small-scale network. Finally, the small-scale networks’ topologies are combined into a topology based on the automatic distribution algorithm of force analysis. As the algorithm transforms the large-scale network topology plane visualization problem into a series of small-scale network topology plane visualization and distribution problems, it has higher parallelism and is able to handle the display of ultra-large-scale network topology

Spatial dynamics of Chinese Muntjac related to past and future climate fluctuations

Climate fluctuations in the past and in the future are likely to result in population expansions, shifts, or the contraction of the ecological niche of many species, and potentially leading to the changes in their geographical distributions. Prediction of suitable habitats has been developed as a useful tool for the assessment of habitat suitability and resource conservation to protect wildlife. Here, we model the ancestral demographic history of the extant modern Chinese Muntjac Muntiacus reevesi populations using approximate Bayesian computation (ABC) and used the maximum entropy model to simulate the past and predict the future spatial dynamics of the species under climate oscillations. Our results indicated that the suitable habitats for the M. reevesi shifted to the Southeast and contracted during the Last Glacial Maximum, whereas they covered a broader and more northern position in the Middle Holocene. The ABC analyses revealed that the modern M. reevesi populations diverged in the Middle Holocene coinciding with the significant contraction of the highly suitable habitat areas. Furthermore, our predictions suggest that the potentially suitable environment distribution for the species will expand under all future climate scenarios. These results indicated that the M. reevesi diverged in the recent time after the glacial period and simultaneously as its habitat’s expanded in the Middle Holocene. Furthermore, the past and future climate fluctuation triggered the change of Chinese muntjac spatial distribution, which has great influence on the Chinese muntjac’s population demographic history

Stability of networked control system with quantization,”

Abstract. This paper is concerned with the control problem of networked control systems (NCSs) with piecewise constant generalized sampled-data hold function (PCGSH

Dynamic Response and Robustness Evaluation of Cable-Supported Arch Bridges Subjected to Cable Breaking

Cable-supported arch bridges have had many cable break accidents, which led to dramatic deck damage and even progressive collapse. To investigate the dynamic response and robustness of cable-supported arch bridges subjected to cable breaking, numerical simulation methods were developed, compared, and analyzed, and an effective and accurate simulation method was presented. Then, the cable fracture of a prototype bridge was simulated, and the dynamic response of the cable system, deck, and arch rib was illustrated. Finally, the robustness evaluation indexes of the cable system, deck, and arch rib were constructed, and their robustness was evaluated. The results show that the dynamic response of the adjacent cables is proportional to the length of the broken cable, while the dynamic response of the deck is inversely proportional to the length of the broken cable. The dynamic amplification factor of the cable tension and deck displacement is within 2.0, while that of the arch rib bending moment exceeds 2.0. The break of a single cable will not trigger progressive collapse. When subjected to cable breaking, the deck system has the least robustness. The proposed cable break simulation procedure and the robustness evaluation method are applicable to both existing and new cable-supported bridges

Research on the Tie Cable Replacement Method of Half-through Tied-Arch Bridge

The tie cable of the half-through tied-arch bridge generally uses external prestressed cables, which need to be replaced regularly similarly to cables and suspenders, but there is very little research in this area at present. Aiming at a method to replace the tie cable for this kind of bridge, this study takes the third Lingjiang bridge, which had damage to the tie cable, as an example. Based on whether there is a temporary cable force-replacement structure, eight replacement schemes are designed. Firstly, the replacement process of each scheme is simulated by the finite-element model, and the influence of each replacement scheme on the upper and lower structures is analyzed. Then, according to the analysis results, the replacement schemes were compared and selected, and the best scheme was determined. Finally, based on the best scheme, the design and construction method of the temporary cable force-replacement structure were given. The results show that the replacement of tie cables of the half-through tied-arch bridge significantly impacts the piles. The internal forces of the pile and arch rib change greatly with the non-substitution method. Adopting the temporary substitution method can not only ensure structural safety but also improve the replacement speed, and the temporary substitution method of replacing one by one symmetrically on both sides proved to be the best. This study can provide a reference for the tie cable replacement of a half-through tied-arch bridge

N-Doped Biochar from Lignocellulosic Biomass for Preparation of Adsorbent: Characterization, Kinetics and Application

Medulla tetrapanacis is composed of a lignocellulosic biopolymer and has a regular porous structure, which makes it a potential biomass material for preparing porous N-doped biochar. Herewith, N-doped Medulla tetrapanacis biochar (UBC) was successfully prepared by modification with urea and NaHCO3 under pyrolysis at 700 °C. The nitrogen-containing groups were efficiently introduced into biochar, and the micro-pore structures of the UBC were developed with sizeable specific surface area, which was loaded with massive adsorption sites. The adsorption kinetics and isotherms of the UBC conformed to pseudo-second-order and Langmuir model. The superior adsorption capacities of the UBC for methylene blue (MB) and congo red (CR) were 923.0 mg/g and 728.0 mg/g, and the capacities for Cu2+ and Pb2+ were 468.5 mg/g and 1466.5 mg/g, respectively. Moreover, the UBC had a stronger affinity for Cr3+ and Fe3+ in multiple metal ions and retained at a preferable adsorption performance for dyes and heavy metals after five cycles. Precipitation, complexation, and physical adsorption were the main mechanisms of the UBC-adsorbing metal ions and dyes. Thus, lignocellulosic biochar has great potential for removing dyes and heavy metals in aqueous solutions

Enhanced room-temperature ferromagnetic properties in ultrathin two-dimensional metal-free poly(triazine imide) nanosheets

Two-dimensional poly(triazine imide) nanosheets have attracted increasing attention due to the diverse functionalities, however, it remains a challenge to synthesize poly(triazine imide) nanosheets directly from molecular monomers. Here, a novel bottom-up ionothermal method of high efficiency was developed for the synthesis of ultrathin amorphous poly(triazine imide) (aPTI) nanosheets from molecular monomers in molten salt. Intriguingly, the aPTI nanosheets exhibit significantly enhanced intrinsic room temperature ferromagnetic behavior in comparison with that of the bulk aPTI material. This work paves a new pathway to synthesize 2D nanomaterial systems with intrinsic ferromagnetic properties, which would have great potential applications in future spintronic devices and other related fields. (C) 2017 Elsevier Ltd. All rights reserved

Enhanced enzymatic sugar production from corn stover by combination of water extraction and glycerol-assisted instant catapult steam explosion

Glycerol-assisted instant catapult steam explosion (ICSE) of lignocellulose is an effective pretreatment method for enhancing sugar production compared to glycerol-free ICSE. In this study, glycerol-assisted ICSE of corn stover was studied in order to understand the reaction mechanisms and further optimize the process. Results showed that water extraction of corn stover prior to ICSE reduced pseudo-lignin formation. The combination of water extraction and glycerol-assisted ICSE led to the formation of lignin with a lower molecular weight (Mw) of 2851 g/mol than 3521 g/mole of that from the combination of water extraction and glycerol-free ICSE. 1H-13C NMR analysis revealed that glycerol likely reacted with lignin carboxylic OHs through esterification while etherification of aliphatic OHs was not observed in ICSE. These lignin analyses indicated that glycerol protected lignin from condensation/repolymerization during glycerol-assisted ICSE. Enzymatic hydrolysis results showed that without water extraction increasing glycerol usage from 0.2 kg/kg stover to 0.4 kg/kg stover improved glucan digestibility to 78% but further increase to 0.5 kg/kg stover reduced glucan digestibility. In addition, at the glycerol usage of 0.2–0.4 kg/kg stover, washing of pretreated stover for removal of glycerol and other biomass-derived compounds did not improve glucan digestibility compared to unwashed ones. Combination of water extraction and glycerol-assisted ICSE led to a high glucan digestibility of 89.7% and a total glucose yield of 25.5 g glucose/100 g stover, which were 30.1% and 7.5 g/100 g stover higher than those derived from glycerol-free ICSE of stover, respectively. Since glycerol is a low-cost carbon source, the resulting enzymatic hydrolysate that contained both glucose and glycerol may be directly used to produce bioproducts by microbial fermentation. Graphical Abstract: (Figure presented.).</p

An Engineered Thermostable Laccase with Great Ability to Decolorize and Detoxify Malachite Green

Laccases can catalyze the remediation of hazardous synthetic dyes in an eco-friendly manner, and thermostable laccases are advantageous to treat high-temperature dyeing wastewater. A novel laccase from Geothermobacter hydrogeniphilus (Ghlac) was cloned and expressed in Escherichia coli. Ghlac containing 263 residues was characterized as a functional laccase of the DUF152 family. By structural and biochemical analyses, the conserved residues H78, C119, and H136 were identified to bind with one copper atom to fulfill the laccase activity. In order to make it more suitable for industrial use, Ghlac variant Mut2 with enhanced thermostability was designed. The half-lives of Mut2 at 50 °C and 60 °C were 80.6 h and 9.8 h, respectively. Mut2 was stable at pH values ranging from 4.0 to 8.0 and showed a high tolerance for organic solvents such as ethanol, acetone, and dimethyl sulfoxide. In addition, Mut2 decolorized approximately 100% of 100 mg/L of malachite green dye in 3 h at 70 °C. Furthermore, Mut2 eliminated the toxicity of malachite green to bacteria and Zea mays. In summary, the thermostable laccase Ghlac Mut2 could effectively decolorize and detoxify malachite green at high temperatures, showing great potential to remediate the dyeing wastewater

Tailored production of citric acid and mannitol by Yarrowia lipolytica from corn stover pretreated by glycerol-assisted instant catapult steam explosion

Yarrowia lipolytica CGMCC 2.1506 was studied for tailored production of citric acid and mannitol by co-utilization of glucose and glycerol as carbon sources. Firstly, optimal cultivation conditions for producing the two products were determined using synthetic (SYN) media. The determined conditions were further applied and verified by Y. lipolytica cultivated with corn stover enzymatic hydrolysate (CSH) media derived from glycerol-assisted instant catapult steam explosion (ICSE) without detoxification, glycerol removal or nutrient addition. A high citric acid concentration of 63.8 ± 2.6 g/L was achieved from CSH media containing 50.0 ± 0.8 g/L glucose and 46.3 ± 2.3 g/L glycerol, in a 5 L bioreactor at pH 5.5. In contrast, a high mannitol concentration of 37.1 ± 1.5 g/L was obtained from a similar hydrolysate at pH 3.5. This study demonstrated that the integrated process based on glycerol-assisted ICSE pretreatment and tailored production of two important building block chemicals by Y. lipolytica is promising for biorefining of lignocellulosic biomass.</p