Abnormal Event Correlation and Detection Based on Network Big Data Analysis

With the continuous development of network technology,various large-scale cyber-attacks continue to emerge.These attacks pose a severe threat to the security of systems,networks,and data.Therefore,how to mine attack patterns from massive data and detect attacks are urgent problems.In this paper,an approach for attack mining and detection is proposed that performs tasks of alarm correlation,false-positive elimination,attack mining,and attack prediction.Based on the idea of CluStream,the proposed approach implements a flow clustering method and a two-step algorithm that guarantees efficient streaming and clustering.The context of an alarm in the attack chain is analyzed and the LightGBM method is used to perform falsepositive recognition with high accuracy.To accelerate the search for the filtered alarm sequence data to mine attack patterns,the PrefixSpan algorithm is also updated in the store strategy.The updated PrefixSpan increases the processing efficiency and achieves a better result than the original one in experiments.With Bayesian theory,the transition probability for the sequence pattern string is calculated and the alarm transition probability table constructed to draw the attack graph.Finally,a long-short-term memory network and embedding word-vector method are used to perform online prediction.Results of numerical experiments show that the method proposed in this paper has a strong practical value for attack detection and prediction.

加热结合水杨酸处理对减轻桃果实冷藏过程中内部褐变的协同效应

研究了热处理（在空气中，38℃，12h）和水杨酸处理（SA，1mM）单独使用以及协同使用时对桃果实冷藏过程中内部褐变（IB）的影响。结果表明，热处理结合水杨酸处理对减轻桃果实0℃贮藏条件下的内部褐变效果最好。经热处理结合水杨酸处理，

Engineer and split an efficient hypercompact CRISPR–CasΦ genome editor in plants

The programmable CRISPR-Cas genome editing technology,adopted from prokaryotic adaptive immune systems,has revolutionized genome engineering in plants(Liu et al.,2022a).Many efforts have been made to improve the activity,specificity,and protospacer adjacent motif(PAM)variants of Class 2 Cas nucleases,such as Cas9,Cas12a,and Cas12b(Liu et al.,2022a).However,their large size(∼1000–1400 amino acids)poses a challenge in scenarios requiring a compact Cas nuclease,particularly in urgent situations like plant virus-induced genome editing(Cheuk and Houde,2018;Li et al.,2021;Varanda et al.,2021).

Fertilization strategy and application model using a centrifugal variable-rate fertilizer spreader

With the sustainable development of precision agriculture and the steady progress of variable-rate fertilization technology,the centrifugal variable-rate fertilizer spreader has attracted research attention due to its lower incidence of crush damage,high efficiency,and low cost.To improve fertilization accuracy and uniformity,spreading performance tests were conducted using this spreader in accordance with the test methods specified in ISO 5690 and ASAE S341.2,in which particle mass was weighed in a two-dimensional matrix of collection boxes.The effects of fertilization strategies that control the feed gate flow rate and the disc rotation speed on particle distribution,and application rate per unit area and effective swath width,were investigated.A variable-rate fertilization model was developed by analyzing the variation characteristics resulting from an increasing and decreasing application rate,and field experiments were conducted to verify its accuracy.The results indicated that when the feed gate flow rate was 300 g/s,the mean application rate was 26.47 g,the standard deviation is 2.81,and the coefficient of variation of particle distribution is at its minimum value of 14.25%.When the disc rotation speed was 600 r/min,the fertilizer was most evenly distributed with a coefficient of variation of 13.86%,and an average effective spreader swath width of 24.51 m.The proposed variable-rate fertilization model showed a high fitting degree with an S-shaped function curve for both increasing and decreasing distribution rates and the yielding coefficients of determination were more than 0.82 and 0.71,respectively.The average error between the model predictions and the test results was 9.47%,and the coefficients of determination for the increasing and decreasing distribution rates were 0.91 and 0.82,respectively,which confirmed the accuracy of the proposed variable-rate fertilization model.This investigation provided a theoretical basis for traditional empirical fertilization using centrifugal variable-rate fertilizer spreaders,and guides the selection of a multiple trajectory,variable-rate fertilization strategy.

Improving uniform scattering device for straw-smashing,back-throwing,no-tillage planter under complete straw mulching condition

With the objective of obtaining a completely straw-mulched field,when no-tillage mechanical sowing is implemented with straw smashing,delivering,and back-throwing approaches,it may be difficult to scatter the smashed straw uniformly during a succeeding wheat sowing step.This is because the previous rice straw is substantial in quantity and has a high humidity and toughness,which may easily result in non-uniform straw mulching and thus sparse and weak seedlings of wheat.Therefore a force-dispersing and uniform-scattering device was designed.With the number of scattering impellers,impeller angle,and impeller rotation speed as the main factors and the percentage of pass for the scattering width and non-uniformity of the straw mulching as the assessment indices,single-factor experiments and orthogonal regressive tests were performed,and a dual-index(percentage of pass for the scattering width and non-uniformity of the straw mulching)fitted regression equation was established.The test results suggested that the main factors(from primary to secondary)that influence the indices were the impeller rotation speed,number of scattering impellers,and impeller angle.The optimal parameter combination for the uniform scattering device was four rows of impellers with an angle of 15°,rotation speed of 1015 r/min,percentage of pass of 72.65%for the scattering width,and a non-uniformity of 13.8%in the straw mulching.This combination can be used to realize a uniform scattering of the smashed straw along the seedling rows on the after-sowing ground.According to the field investigation of the wheat growth,the wheat emergence rate was 90.7%.The research results can provide a reference for improving the uniform scattering device for a straw-smashing,back-throwing,no-tillage planter for obtaining a completely straw-mulched field,enhancing the quality of the machinery operation,and ensuring good and strong seedlings after sowing.

Determination of damaged wheat kernels with hyperspectral imaging analysis

Hyperspectral imaging was applied to classify the damaged wheat kernels and healthy kernels.The spectral information was extracted from damaged wheat kernels and healthy kernels samples.The effective wavelengths were obtained from spectral of 865-1711 nm by X-loadings of principal component analysis(PCA)and successive projection algorithm(SPA)method,respectively.Partial least square method(PLS)and least square-support vector machine(LS-SVM)were then used to build classification models on full spectral data and effective wavelengths dataset,respectively.The results showed that the classification accuracy of every LS-SVM model was the best,being 100%.While the accuracy of the PLS model was slightly lower,still over 97%.The confusion matrix showed that several damaged wheat kernels samples were misclassified as healthy samples,while all healthy samples were correctly classified.The overall results indicated that hyperspectral imaging could be used for discriminating the damaged wheat kernels and could provide a reference for detecting other grain kernels grading degrees.Further,this study can provide a research basis for the development of online or portable detectors on grain damaged kernels recognition,which will be beneficial for grain grading or post-harvest quality processing of other grains.

Experimental determination of restitution coefficient of garlic bulb based on high-speed photography

Restitution coefficient(RC)of garlic bulb is an important mechanical property that is required to establish the kinematics model of bulb collision and research the damage mechanism of bulb collision.In this study,kinetic equations of bulb collision were established based on Hertz's contact theory.The kinematics characteristics,elastoplastic deformation and contact damage during bulb collision were analyzed by using high-speed photography.The effects of bulb mass,moisture content,collision material,material thickness and release height on the RC were investigated by mixed orthogonal experiments and single-factor experiments.The results showed that the movement of bulb in the compression stage was translation,and the movement in the rebound stage was translation and rotation.During collision,the larger the rotational angular velocity of the bulb was,the smaller the measured RC would be.The contact damage of bulb included internal damage of the tissue,epidermis stretch and tear.The significance of effects of factors on RC decreased with the following sequence:collision material,release height,material thickness,bulb mass,and moisture content.Collision material,release height,material thickness,and bulb mass were significant factors.The RC between the bulb and Q235,nylon,and rubber decreased sequentially.The RC decreased with the increase of release height and bulb mass.The RC increased with the increase of material thickness of Q235,while it decreased with the increase of material thickness of rubber or Nylon.The determination coefficients of the regression equations between the significant factors and the RC were all greater than 0.96.The results will be helpful for damage mechanism analysis and design of garlic production equipment.

Optimization and experiment of key components in pneumatic peanut pod conveyor

Research interest in pneumatic conveying technologies in processes such as peanut harvesting and shelling has grown rapidly in recent years.However,the use of pneumatic conveyors in this application suffers from high pod damage rates and duct obstruction.To address these issues,we analyzed the critical speed of pneumatic transport for conveying the peanut pods and measured the angle of friction and coefficient of restitution of peanut pods on a variety of material surfaces.Based on the results of these tests,optimizations and improvements were made to the separator bowl,air supply duct,and conveying duct.A pneumatic conveying experiment was then performed using peanut pods.In the factorial experiment,it was found that increases in fan speed increase the pod damage rate and transport efficiency,while increases in the thickness of the cushioning/anti-obstruction layer decrease the rate of pod damage and transport efficiency.Pod damage rates were significantly affected by fan speed,the thickness of the cushioning/obstruction prevention layer,and interaction between these factors,while transport efficiency was only significantly affected by fan speed.It is proved by the machine verification test,the optimal parameters for the pneumatic transport of Baisha peanut pods with a moisture content of 7.24%was a fan speed of 2700 r/min and a cushioning/anti-obstruction layer thickness of 6 mm.A pod damage rate of 5.19%and transport efficiency of 92.03%were achieved using these parameters,which are sufficient for meeting the requirements of industrial applications.

Adaptabilities of different harvesters to peanut plants after cutting stalks

At present,there are no harvesters specifically adapted to process peanuts after cutting stalks.In particular,methods for harvesting peanuts after cutting stalks have not been reported thus far.Therefore,to utilize peanut stalks as feed when harvesting plastic-film-grown peanuts,and to improve industry benefits,a three-stage harvesting method is proposed herein.In view of the three-stage harvesting method,the peanut stalks are cut before digging,with the remaining peanut plants being shorter,thereby increasing the peanut pod-stalk ratio.To investigate the adaptabilities of existing harvesters in harvesting peanuts after cutting stalks,three types of peanut harvesters-the self-propelled pick-up combine harvester,trailed pick-up combine harvester,and peanut picker were used to conduct a comparative test on harvesting intact peanut plants and plants after cutting stalks.The loss,breakage and impurity rates were used as evaluation indicators.The loss rates of these three harvesters were 14.64%,16.44%and 1.33%;the breakage rates were 21.28%,21.92%and 20.00%,and impurity rates were 4.60%,8.76%and 9.06%.Analysis of variance showed that cutting stalks had a significant impact on the work qualities of the three harvesters(p<0.05).With regard to the loss rate,results revealed that:the two peanut combine harvesters could not be adapted to harvest peanut plants after cutting stalks.The three harvesters had good adaptability to harvest peanut plants after cutting stalks,considering the breakage rate;however,based on the impurity rate,the three harvesters could not be adapted to harvest peanut plants after cutting stalks.The losses of the two combine harvesters consisted mainly of dropped and missed picking,with the sum of the losses accounting for 99.87%and 97.99%of the total losses of the two harvesters,respectively;this suggests that the drum pickup of the combine harvesters could not adapt to harvesting the peanut after cutting stalks.The breakage rates of the three harvesters were considerably reduced,suggesting that the pod picking devices of the three harvesters were suitable for harvesting the peanut after cutting stalks;the impurity rates of the three harvesters were considerably increased,indicating that the pod picking and cleaning devices of the three harvesters were not suitable for harvesting peanut after cutting stalks.To improve the adaptabilities of the harvesters,it is suggested that the speed of pickup elastic tooth,lateral spacing between adjacent elastic teeth,concave screen hole size of pod picking device,the structure and motion parameters of cleaning device should be optimized.The results of this study provide a reference for the development and improvement of peanut harvesters suitable for harvesting peanuts after the cutting of stalks.

Experiment and parameter optimization of an automatic row following system for the traction beet combine harvester

To improve the automation level and operation quality of China's beet harvester and reduce the loss due to damaged and missed excavation,this study used a self-developed sugar beet combine harvester and field simulation experiment platform,based on the single-factor bench test of the automatic row following system in the early stage,taking hydraulic flow A,spring preload B,and forward speed C which have significant influence on performance indices as test factors,and taking the missed excavation rate,breakage rate and reaction time as performance indices,the orthogonal experimental study on the parameter optimization of the three-factor and three-level automatic row following system with the first-order interaction of various factors was carried out.The results of the orthogonal experiments were analyzed using range analysis and variance analysis.The results showed that there were differences in the influence degree,factor priority order and first-order interaction,and the optimal parameter combination on each performance index.A weighted comprehensive scoring method was used to optimize and analyze each index.The optimal parameter combination of the overall operating performance of the automatic row following system was A 2B 2C 1,that is,the hydraulic flow was 25 L/min,the forward speed was 0.8 m/s,and the spring preload was 198 N.Under this combination,the response time was 0.496 s,the missed excavation rate was 2.35%,the breakage rate was 3.65%,and the operation quality was relatively good,which can meet the harvest requirements.The comprehensive optimization results were verified by field experiments with different ridge shapes and different planting patterns.The results showed that the mean values of the missed excavation rate of different planting patterns of conventional straight ridges and extremely large"S"ridges were 2.23%and 2.69%,respectively,and the maximum values were 2.39%and 2.98%,respectively;the average damage rates were 3.38%and 4.14%,and the maximum values were 3.58%and 4.48%,which meet the industry standards of sugar beet harvester operation quality.The overall adaptability of the automatic row following system is good.This study can provide a reference for research on automatic row following harvesting systems of sugar beets and other subsoil crop harvesters.

Optimization and experiment on key structural parameters of no-tillage planter with straw-smashing and strip-mulching

Accelerate the quality of smashed-straw laying and enhance the effect of seed-bed arranging for no-tillage planter with straw-smashing and strip-mulching in full stubble covered paddy have become imperative in implementing modern conservation tillage.Considering the perfect operating performance(passability and stability)of the developed no-tillageplanter,this study intends to optimize the structure design of smashed-straw diversion device and strip-rotary tillage device.Dynamics equations of smashed straw and kinematics models of rotary blades were established through theoretical analysis,and the principal factors that affecting straw strip-laying quality and seed-bed arranging effect were specified.The influence of out-enlarge angle(η)and slide-push angle(γ)of the diversion device on the coefficient of variation(ζ1)of cover-straw width,and the influence of rotary tillage-blade number(N)and configuration in a singlerotary plane on the broken rate(ζ2)of strip soil were completely analyzed.And then,based on the systematic analysis and integrated scheme,operating performance and field verification tests using the optimized no-tillage planter were thoroughly performed.The results of the performance tests indicated that the out-enlarge angle(η)had a highly significant influence on the coefficient of variation(ζ1),and the slide-push angle(γ)had a significant influence on(ζ1).The rotary tillage-blade number(N)had a highly significant influence on the broken rate(ζ2),and the slide-push angle(γ)had a significant influence on(ζ2).The obtained optimal combination of these key structure parameters through comprehensive analysis wasη=45°,γ=40°,and N=4.Field verification test results indicated that the optimized no-tillage planter achieved mean values of ζ1=10.47%and ζ2=90.95%,which satisfied the relevant operation quality and cultivation agricultural requirement of conservation tillage equipment,and provided technical references for developing the similar no-tillage planter of straw crushing and returning.

Design and modelling of the full-feed peanut picking device with selfadaptive adjustable working clearance and feeding rate

To improve the declining performance of a full-feed peanut picking device or solve the mechanical failures that occur due to fluctuations in the feeding rate during operation,the 4HLJI-3000 peanut intelligent picking combine harvester,which is a picking device with a self-adaptive adjustment of the working clearance,was developed as the research object in this study.Moreover,the key components,such as the picking roller,concave plate sieve and clearance adjustment mechanism of the concave plate sieve,were designed and analysed.Through the force analysis of the concave plate sieve of the picking device,the mathematical model of the concave plate sieve displacement of the picking device and feeding rate was obtained.The software system for monitoring,storing and analysing the concave plate sieve displacement of the picking device based on EasyBuilder Pro was designed,and the road monitoring test of displacement variation of concave plate sieve of the picking device and feeding rate was carried out.The linear function,power function,exponential function,quadratic function,compound function,logarithmic function and cubic function fitting were used to perform regression analysis of the test results by using IBM SPSS software.The results showed that the cubic function model had a higher fitting precision,and its determination coefficient was 0.992.Model verification experiments were proposed,and the results showed that the established cubic function model had a good accuracy.The absolute deviation rate ranged from 0 to 4.83%,and the average deviation rate was 2.22%.The deviation rate increased with an increasing feeding rate.The field experiments also proved that there was a cubic function relationship between the feeding rate and concave plate sieve displacement,the measured concave plate sieve displacement deviation rate ranged from 0 to 6.19%,and the average deviation rate was 2.73%compared with the calculated results.This study can provide a reference for the optimization design of the structure of full-feeding picking devices for peanuts and other crops and the intelligent measurement and control of the feeding rates.

Development of a multi-adaptive feeding device for automated plug seedling transplanter

In order to improve the adaptability of the seedling feeding devices to different plug trays for various seedlings,a multi-adaptive plug seedling feeding device for automatic field transplantation was developed.Its efficiency and adaptability have been improved using a seedling delivery device equipped with a row of end-effectors,which were provided with continuous plug seedlings by a compact seedling tray conveyor carrying out a reciprocating action.Each operation for the seedling feeding device could work automatically through a control system.Three categories of plug seedlings,cucumber,pepper and tomato seedlings were tested.The results of the performance test for the prototype demonstrated that the best performance emerged in the cucumber seedlings in 50-cell trays with the highest success rate of 88%at the feeding frequency of 6 groups/min.The lowest success rate was 73.33%for the tomato seedlings in 105-cell trays at the feeding frequency of 12 groups/min.It can be concluded that the automated feeding device developed in this study could be used for various plug seedlings as a result of its strong adaptability.

Research and optimization of the hand-over lifting mechanism of a sweet potato combine harvester based on EDEM

In order to meet the challenge of high loss rate and high tuber injury rate during the operation of the 4UZL-1 sweet potato combine harvester,the sweet potato tuber hand-over lifting mechanism was designed based on a comprehensive analysis of the entire structure of the harvester.Taking the average normal force on conveying sweet potato tubers as evaluation indexes,the EDEM simulation experiment was carried out considering the factors of the angle of the excavating and conveying mechanism,the conveying angle of the scraper chain,the speed of the excavating and conveying mechanism,and the speed of the scraper chain conveying.The experimental findings indicated that the optimal operational performance of the hand-over lifting mechanism was achieved at a speed of 1.15 m/s for the excavating and conveying mechanism,an angle of 24°for the excavating and conveying mechanism,a conveying speed of 0.66 m/s for the scraper chain,and a conveying angle of 60°for the scraper chain.Field experiments were conducted based on the EDEM simulation experiment,using the loss rate and the injury rate of conveying sweet potato tubers as evaluation indexes.The results showed that the hand-over lifting mechanism demonstrated optimal operational effectiveness with an excavating and conveying mechanism angle of 20°,a scraper chain angle of 68°,an excavating and conveying mechanism speed of 1.2 m/s,and a scraper chain speed of 0.66 m/s,while the machine running speed was maintained at 1 m/s.At the moment,the hand-over lifting structure exhibited a loss rate of 1.12%and a tuber injury rate of 0.94%.The conclusions obtained serve as a valuable reference for future research and optimization of sweet potato combines.

Operation analysis and parameter optimization of the conveying device for uniform crushed straw throwing and seed-sowing machines

Uniform crushed straw throwing and seed-sowing machines can achieve the processes of straw chopping,straw transport,sowing,fertilization,and straw mulching at the same time,which is widely used in many areas of China.Conveying device is one of the important components used to convey,elevate and throw straw.However,the problems of high power consumption and congestion affect the promotion of the machine.Therefore,the conveying device of uniform crushed straw throwing and seed-sowing machine was analyzed in order to determine its device operation mechanism.Kinematic and dynamic analyses of particles of crushed rice straw during lifting and dispersion are used to develop a flexible-body model of rod-shaped and agglomerate-shaped crushed straw and a coupling model including the mechanical structure of the device.By integrating computational fluid dynamics and the discrete element method,the gas-solid coupling theory in numerical simulations and motion analysis of crushed straw particles is used to determine how the flow field and motion characteristics affect the conveying performance.Besides,regression equations to describe the relationships between the factors and each assessment index were established by using the regression analysis and response surface analysis with the software Design-Expert.The effect of throwing blade speed X_(1),conveying volume of crushed straw X_(2),and pipeline diameter X_(3) on the throwing speed of crushed straw Y_(1) and specific power consumption Y2 were investigated.The highest throwing speed of crushed straw and lowest specific power consumption are the optimization goal.The results of optimization showed that the predict the best optimal parameters were 2000 r/min throwing blade rotational speed,1.4 kg/s conveying volume,and 220 mm pipeline diameter,the planter achieved a throwing speed of 12.2 m/s and specific power consumption of 9179 m^(2)/s^(2).And then a field test verification was conducted.The planter achieved a throwing speed 12.4 m/s and specific power consumption 9070 m^(2)/s^(2) while selecting the best optimal parameters.Thus,the optimal parameters can provide a high-performance operation and satisfy the actual operation requirements The results provide a theoretical basis and data support for seeding technology innovation and equipment optimization to ensure uniform crushed straw throwing in dense rice stubble fields.