ProbD: Faulty Path Detection Based on Probability in Software-Defined Networking

With the increasing number of switches in Software-Defined Network-ing(SDN),there are more and more faults rising in the data plane.However,due to the existence of link redundancy and multi-path forwarding mechanisms,these problems cannot be detected in time.The current faulty path detection mechan-isms have problems such as the large scale of detection and low efficiency,which is difficult to meet the requirements of efficient faulty path detection in large-scale SDN.Concerning this issue,we propose an efficient network path fault testing model ProbD based on probability detection.This model achieves a high prob-ability of detecting arbitrary path fault in the form of small-scale random sam-pling.Under a certain path fault rate,ProbD obtains the curve of sample size and probability of detecting arbitrary path fault by randomly sampling network paths several times.After a small number of experiments,the ProbD model can cor-rectly estimate the path fault rate of the network and calculate the total number of paths that need to be detected according to the different probability of detecting arbitrary path fault and the path fault rate of the network.Thefinal experimental results show that,compared with the full path coverage test,the ProbD model based on probability detection can achieve efficient network testing with less overhead.Besides,the larger the network scale is,the more overhead will be saved.

Stability Analysis of Large Section Rocky Tunnel Support Structure

In order to study the stress characteristics of the initial support and secondary lining of the large section tunnel and to solve the problem of secondary lining cracking during operation. Taking the large section tunnel in Zihong village, Qi County as the research object, a numerical simulation method was used to establish a finite element model of the large section tunnel. So as to simulate and analyze the stress characteristics of the support structure of this tunnel. Through the simulation of the initial support and second lining of this large section tunnel in terms of displacement, stress, plastic zone damage and anchor shaft force, the results show that as the excavation progresses, the stress and displacement on the surface of the newly excavated tunnel profile is faster, especially at the side walls and arch footings, the stress and displacement values are slightly larger than other characteristic points, but the final values are stable and converge, and are basically consistent with the field monitoring results, which indicates that this support system is basically in stable state. Therefore, during the tunnel excavation and support process, special attention should be paid to the stability of the sidewalls and footings, and the results of this study will be of great practical significance for tunnel construction and maintenance.

Effect of black and white sesame on lowering blood lipids of rats with hyperlipidemia induced by high-fat diet

Sesamum indicum has various biological effects,and this study aimed to investigate its hypolipidemic effect.A hyperlipidemia rat model was established by feeding rats with high-fat diets in this study,then the hyperlipidemia rats were fed with different doses of black and white sesame seeds and black and white sesame kernels.The serum and liver biochemical indicators of the rats were determined,and liver pathology analysis was conducted to evaluate the hypolipidemic effect of sesame.The results showed that the blood lipid of SD(Sprague-Dawley)rats fed with high-fat diet for three weeks was higher than 200 mg/d L,indicating that the hyperlipidemia rat model was successfully established.At the same dose,the final body weights of the rats of white sesame seed and kernel groups were higher than those of the black sesame seed and kernel groups;and the weights of the black and white sesame seed groups were lower than those of the black and white sesame kernel groups.The liver indexes of the normal control group and the experimental groups were significantly lower than the model control group(P<0.05),indicating that black and white sesame seed and kernel could reduce the lipid accumulation on the liver.The malondialdehyde(MDA)values of the liver in the normal control group and the experimental groups were significantly lower than that in the model control group(P<0.05).The total antioxidant capacity(T-AOC),high density lipoprotein cholesterol(HDL-C),glutathione peroxidase(GSH-Px)and total superoxide dismutase(T-SOD)in the liver of each experimental group were significantly higher than those in the model control group(P<0.05).Based on the above results as well as pathological observation and analysis,we found that the black and white sesame seeds and kernels could improve fatty liver lesions and lipid metabolism disorder and could reduce lipid accumulation on the liver,thereby protecting the liver from damage and reducing the risk of fatty liver.Moreover,black and white sesame seeds,black and white sesame kernels can reduce the levels of total cholesterol(TC)and triglyceride(TG)in serum,and high dose of black sesame seeds(30%black sesame seeds)and low dose of black sesame kernels(10%black sesame kernels)were more beneficial for the recovery of hyperlipidemia and fatty liver.The above results indicated that black and white sesame has hypolipidemic effect.

Dissolution and recrystallization of perovskite induced by N-methyl-2-pyrrolidone in a closed steam annealing method

High quality perovskite films with large columnar grains are greatly desired for efficient perovskite solar cells. Here, low volatility N-methyl-2-pyrrolidone(NMP) was added in MAI/IPA solution in a two-step spin-coating method, which promoted the conversion of lead iodide to perovskite. The perovskite films were annealed by a closed-steam annealing method to prolong the recrystallization process of perovskite films assisted by the residual NMP. It leaded to high quality CH_3NH_3PbI_3 perovskite films with large columnar grains due to its enhancement of the Oswald ripening. The large grain perovskite film leaded to efficient carrier transformation and injection, and low recombination. The photovoltaic performance of the perovskite solar cells was improved significantly.

Particle Swarm Optimization Applied to Some Anti-Windup Problems

The particle swarm optimization (PSO) algorithm is introduced to deal with some open anti-windup problems, i.e., determining the initial condition when applying the iterative algorithm to enlarge the estimate of the domain of attraction, determining the design point in the delayed anti-windup scheme, and determining the design point and the weighting factors in the multi-stage anti-windup scheme. Therefore, the corresponding PSO-based algorithms are proposed. Unlike the traditional methods in which the free design parameters can only be selected by trial and error with the available computational results, the PSO-based algorithms provide a systematic way to determine these parameters. In addition, the algorithms are easy to be implemented and are very likely to find the desirable parameters that further improve the anti-windup closed-loop performances. Simulation results are presented to validate the effectiveness and advantages of the proposed method.

Fast Verification of Network Configuration Updates

With the expansion of network services,large-scale networks have progressively become common.The network status changes rapidly in response to customer needs and configuration changes,so network configuration changes are also very frequent.However,no matter what changes,the network must ensure the correct conditions,such as isolating tenants from each other or guaranteeing essential services.Once changes occur,it is necessary to verify the after-changed network.Whereas,for the verification of large-scale network configuration changes,many current verifiers show poor efficiency.In order to solve the problem ofmultiple global verifications caused by frequent updates of local configurations in large networks,we present a fast configuration updates verification tool,FastCUV,for distributed control planes.FastCUV aims to enhance the efficiency of distributed control plane verification for medium and large networks while ensuring correctness.This paper presents a method to determine the network range affected by the configuration change.We present a flow model and graph structure to facilitate the design of verification algorithms and speed up verification.Our scheme verifies the network area affected by obtaining the change of the Forwarding Information Base(FIB)before and after.FastCUV supports rich network attributes,meanwhile,has high efficiency and correctness performance.After experimental verification and result analysis,our method outperforms the state-of-the-art method to a certain extent.

Memory-Occupied Routing Algorithms for Quantum Relay Networks

Quantum transmission experiments have shown that the success-ful transmission rate of entangled quanta in optical fibers decreases expo-nentially.Although current quantum networks deploy quantum relays to establish long-distance connections,the increase in transmission distance and entanglement switching costs still need to be considered when selecting the next hop.However,most of the existing quantum network models prefer to consider the parameters of the physical layer,which ignore the influence factors of the network layer.In this paper,we propose a meshy quantum network model based on quantum teleportation,which considers both net-work layer and physical layer parameters.The proposed model can reflect the realistic transmission characteristics and morphological characteristics of the quantum relay network.Then,we study the network throughput of different routing algorithms with the same given parameters when multiple source-destination pairs are interconnected simultaneously.To solve the chal-lenges of routing competition caused by the simultaneous transmission,we present greedy memory-occupied algorithm Q-GMOA and random memory-occupied algorithm Q-RMOA.The proposed meshy quantum network model and the memory-occupied routing algorithms can improve the utilization rate of resources and the transmission performance of the quantum network.And the evaluation results indicate that the proposed methods embrace a higher transmission rate than the previous methods with repeater occupation.

Performance Evaluation of Topologies for Multi-Domain Software-Defined Networking

Software-defined networking(SDN)is widely used in multiple types of data center networks,and these distributed data center networks can be integrated into a multi-domain SDN by utilizing multiple controllers.However,the network topology of each control domain of SDN will affect the performance of the multidomain network,so performance evaluation is required before the deployment of the multi-domain SDN.Besides,there is a high cost to build real multi-domain SDN networks with different topologies,so it is necessary to use simulation testing methods to evaluate the topological performance of the multi-domain SDN network.As there is a lack of existing methods to construct a multi-domain SDN simulation network for the tool to evaluate the topological performance automatically,this paper proposes an automated multi-domain SDN topology performance evaluation framework,which supports multiple types of SDN network topologies in cooperating to construct a multi-domain SDN network.The framework integrates existing single-domain SDN simulation tools with network performance testing tools to realize automated performance evaluation of multidomain SDN network topologies.We designed and implemented a Mininet-based simulation tool that can connect multiple controllers and run user-specified topologies in multiple SDN control domains to build and test multi-domain SDN networks faster.Then,we used the tool to perform performance tests on various data center network topologies in single-domain and multi-domain SDN simulation environments.Test results show that Space Shuffle has the most stable performance in a single-domain environment,and Fat-tree has the best performance in a multi-domain environment.Also,this tool has the characteristics of simplicity and stability,which can meet the needs of multi-domain SDN topology performance evaluation.

Cu nanowire array with designed interphases enabling high performance Si anode toward flexible lithium-ion battery

To meet the growing demand for wearable smart electronic devices,the development of flexible lithium-ion batteries(LIBs)is essential.Silicon is an ideal candidate for the anode material of flexible lithium-ion batteries due to its high specific capacity,low working potential,and earth abundance.The largest challenge in developing a flexible silicon anode is how to maintain structural integrity and ensure stable electrochemical reactions during external deformation.In this work,we propose a novel design for fabricating core–shell electrodes based on a copper nanowire(CuNW)array core and magnetron sputtered Si/C shell.The nanowire array structure has characteristics of bending under longitudinal stress and twisting under transverse stress,which helps to maintain the mechanical stability of the structure during electrode bending and cycling.The low-temperature annealing generates a small amount of Cu3Si alloy,which enhances the connection strength between Si and the conductive network and solves the poor conductivity problem of Si,which is known as a semiconductor material.This unique configuration design of CuNW@Si@C-400℃ leads to stable long cycle performance of 1109 mAh∙g^(-1) after 1000 cycles and excellent rate performance of 500 mAh∙g^(-1) at a current density of 10 A∙g^(-1).Furthermore,the CuNW@Si@C-400℃||LiFePO_(4)(LFP)full battery demonstrates excellent flexibility,with a capacity retention of more than 96%after 100 bends.This study provides a promising strategy for the development of flexible lithium-ion batteries.

Mapping of wheat stripe rust resistance gene Yr041133 by BSR-Seq analysis

Puccinia striiformis Westend. f. sp. tritici(Pst) pathotype CYR34 is widely virulent and prevalent in China.Here, we report identification of a strpie rust resistance(Yr) gene, designated Yr041133, in winter wheat line 041133. This line produced a hypersensitive reaction to CYR34 and conferred resistance to 13 other pathotypes. Resistance to CYR34 in line 041133 was controlled by a single dominant gene. Bulked segregant RNA sequencing(BSR-Seq) was performed on a pair of RNA bulks generated by pooling resistant and susceptible recombinant inbred lines. Yr041133 was mapped to a 1.7 c M genetic interval on the chromosome arm 7 BL that corresponded to a 0.8 Mb physical interval(608.9–609.7 Mb) in the Chinese Spring reference genome. Based on its unique physical location Yr041133 differred from the other Yr genes on this chromosome arm.

MONTE CARLO SIMULATION OF MULTIFOCAL STOCHASTIC SCANNING SYSTEM

Multifocal multiphoton microscopy(MMM)has greatly improved the utilization of excitationlight and imaging speed due to parallel multiphoton excitation of the samples and simultaneousdetection of the signals,which allows it to perform three-dimensional fast fuorescence imaging.Stochastic scanming can provide continuous,uniform and high-speed excitation of the sample,which makes it a suitable scanning scheme for MMM.In this paper,the graphical programminglanguage,LabVIEW is used to achieve stochastic scanning of the two-dimensional galvo scanmers by using white noise signals to control the a and y mirrors independently.Moreover,thestochastic scanning process is simulated by using Monte Carlo method.Our results show that MMM can avoid oversampling or subsampling in the scanning area and meet the requirements of uniform sampling by stochastically scanning the individual units of the N×N foci array.Therefore,continuous and umiform scaning in the whole field of view is implemented.

Teaching Reform and Practice on Course Construction of Discrete Mathematics

Discrete mathematics studies the respective structures,laws and interrelationships of different discrete quantities,which has a wide range of applications in computer science and software engineering.It has the characteristics of research,practice and innovation.The teaching goals of the course of discrete mathematics include not only the understanding and mastery of knowledge,but also the study of methodology.However,current teaching mechanism has limitations in outdated course contents,rare real project examples and nonscientific scoring modes.This paper attempts to think about the course construction of discrete mathematics to improve the teaching effects and cultivate students’practical ability.

Design, Synthesis and Application of a Robust d_(3)-Methyithiolating Reagent

A deuterated methylthiolating reagent with a broad spectrum,designated as DMTp,has been ingeniously formulated.This new reagent can be produced with high efficiency through the simple combination of commercially available methyl 3-thiopropanoate and CD_(3)l.This novel SCD_(3) reagent exhibits excellent reactivity with electrophiles such as alkyl iodides,benzyl chlorides,aryl halides(l,Br)and aryl triflates,resulting in high levels of deuterium content(99%D).Representative deuterated methylthiolated biomolecules,such as Sulfoxaflor,havebeen synthesizedforuse in pharmaceutical discoveryand development.

Length-dependent alignment of large-area semiconducting carbon nanotubes self-assembly on a liquid–liquid interface

Aligned arrays of semiconducting carbon nanotubes(s-CNTs)with high homogenous density and orientation are urgently needed for high-performance carbon-based electronics.Herein,a length-controlled approach using combined technologies was developed to regulate the s-CNT length and reduce the length distribution.The impact of different lengths and length distributions was studied during aligned self-assembly on a liquid–liquid confined interface was investigated.The results show that short s-CNTs with a narrow distribution have the best alignment uniformity over the large scale.The optimized and aligned s-CNT array can reach a density as high as 100 CNTs·μm−1 on a 4-inch wafer.The field-effect transistor(FET)performance of these optimized s-CNT arrays was 64%higher than arrays without length-control.This study clarified that rational control of s-CNTs with desired length and length distribution on the aligned self-assembly process within the liquid–liquid confined interface.The results illustrate a solid foundation for the application of emerging carbon-based electronics.

Low Voltage Direct Current Supply and Utilization System:Definition,Key Technologies and Development

With rapid increase of distributed solar power generation and direct current(DC)based loads such as data centers,electric vehicles(EVs),and DC household appliances,the development trend of the power system is changed from conventional alternate current(AC)to DC.Traditional AC power systems can scarcely meet the development demand of new DC trends,especially since both the generation side and load side are comprised of DC-based electronic power components.With this background,low voltage direct current supply and utilization system(LVDCSUS)has attracted more and more attention for its great advantages over an AC grid to overcome challenges in operation,reliability,and energy loss in renewable energy connection,DC load power utilization and a number of other aspects.However,the definition of the LVDCSUS is still not clear even though many demonstration projects have been put into planning and operation.In order to provide a clear description of LVDCSUS,first,the characteristics of LVDCSUS are illustrated in this paper to show the advance of the LVDCSUS.Second,the potential application scenarios of LVDCSUS are presented in this paper.Third,application of LVDCSUS technologies and some demonstration projects in China are introduced.Besides the development of the LVDCSUS,key technologies,including but not limited to planning and design,voltage levels,control strategies,and key equipment of LVDCSUS,are discussed in this paper.Finally,future application areas and the research orientations of LVDCSUS are analyzed.

Post-hepatoportoenterostomy Acoustic Radiation Force Impulse Elastography to Predict Two-year Outcome of Biliary Atresia

Background and Aims: Early identification of prognostic factors to predict transplant/death outcome of biliary atresia (BA) is challenging. We aimed to investigate the longitudinal changes and predictive value of dynamic changes in acoustic radiation force impulse elastography with shear wave speed (SWS) quantification and other parameters within three months after hepatoportoenterostomy (HPE) for 2-year BA outcomes. Methods: Seventy-four patients who underwent HPE between July 2016 and June 2019 were prospectively enrolled. Outcomes were classified into native liver survival and transplant/death groups. Acoustic radiation force im-pulse elastography was performed sequentially at 3 months intervals post-HPE. Cox regression analysis was used to de-termine the superior SWS values and other predictors of liver transplantation or death. Results: Among patients 2 years of age, 36 survived with a native liver, nine died, and 29 underwent liver transplantation. The trend in SWS levels in the transplant/death group was significantly different from that in the native liver survival group. ΔSWS at 1-3 months post-HPE and total bilirubin at 1 month post-HPE were se-lected as superior predictors of liver transplantation or death using multivariate Cox regression models: hazard ratio (HR)=1.927;95% confidence interval (CI): 1.475-2.661;p<0.001 and HR=1.010;95% CI: 1.003-1.017;p=0.007, respectively. The combination of the selected ΔSWS and total bilirubin had good predictive power, with an area under the receiver operating characteristics curve of 0.89, specificity 94.44% and sensitivity 73.68%. Conclusions: Our results suggest that early postoperative bilirubin levels and SWS changes were reliable predictors of 2-year BA outcomes.

炼化反渗透浓水中有机物处理技术

双膜工艺作为一种有效的废水处理方法,已被炼化企业广泛采用。然而,该工艺在使用过程中会产生一定量的含有机物高盐反渗透浓水(ROCs)。在国家排放标准对废水外排指标日趋严格的情况下,反渗透浓水直接外排已被禁止。因此,含有机物高盐反渗透浓水处理技术成为研究的热点。本文对炼化反渗透浓水处理技术研究进展进行综述和讨论。首先本文对不同炼化企业反渗透浓水的组成进行了汇总和分析;其次,对反渗透浓水中有机物的去除技术,如物理化学方法、高级氧化法和生化方法等,进行了详细讨论,并深入分析了新兴高级氧化工艺的机理和优缺点;最后对炼化反渗透浓水中盐回收技术进行了讨论。

MoS2 yolk-shell microspheres with a hierarchical porous structure for efficient hydrogen evolution

Yolk-shell architectures have attracted extensive attention owing to their unique structure and infusive applications. MoS2 is regarded as one of the most promising catalytic materials for hydrogen evolution by the splitting of water. In this work, a simple self-template solvothermal approach is developed for the synthesis of novel MoS2 yolk-shell microspheres with a hierarchical porous structure by reacting MoO2 microspheres with L-cysteine. A dissolution- recrystallization formation mechanism is proposed for the MoS2 yolk-shell microspheres. Owing to structural superiority, the new material architecture exhibits improved photoelectrochemical properties, including efficient hydrogen evolution reaction catalytic activities, a high photocurrent density, a small overpotential, and a low charge-transfer resistance.

Synthesis and facet-dependent photocatalytic activity of strontium titanate polyhedron nanocrystals

Cubic-perovskite （SrTiO3） has a great potential to be utilized in a wide range of applications. However, currently very little is known about the shape and facet effects of SrTiO3 on their physicochemical properties. This is largely owing to the difficulties in controlling the morphology of facets during synthesis. Herein, we describe a facile route for the facet- and size-controlled fabrication of single- crystalline SrTiO3 triangular prisms with highly exposed {101} side faces and {111} end faces. Theoretical and experimental studies of their photocatalytic performance have shown that triangular prisms exhibit superior photocatalytic activities than nanocubes with exposed （001） faces for the degradation of organic contaminants, which may be primarily attributed to the much higher surface energy of {101} facets （2.97 J/m^2） and {111} facets （2.80 J/m^2） than of that of {001} facets （0.98 J/m^2）.

Freshness constraints of an age of information based event-triggered Kalman consensus filter algorithm over a wireless sensor network

This paper presents the design of a new event-triggered Kalman consensus filter(ET-KCF)algorithm for use over a wireless sensor network(WSN).This algorithm is based on information freshness,which is calculated as the age of information(Aol)of the sampled data.The proposed algorithm integrates the traditional event-triggered mechanism,information freshness calculation method,and Kalman consensus filter(KCF)algorithm to estimate the concentrations of pollutants in the aircraft more efficiently.The proposed method also considers the influence of data packet loss and the aircraft's loss of communication path over the WSN,and presents an Aol-freshness-based threshold selection method for the ET-KCF algorithm,which compares the packet Aol to the minimum average Aol of the system.This method can obviously reduce the energy consumption because the transmission of expired information is reduced.Finally,the convergence of the algorithm is proved using the Lyapunov stability theory and matrix theory.Simulation results show that this algorithm has better fault tolerance compared to the existing KCF and lower power consumption than other ET-KCFs.