The fast increase of online communities has brought about an increase in cyber threats inclusive of cyberbullying, hate speech, misinformation, and online harassment, making content moderation a pressing necessity. Tr...The fast increase of online communities has brought about an increase in cyber threats inclusive of cyberbullying, hate speech, misinformation, and online harassment, making content moderation a pressing necessity. Traditional single-modal AI-based detection systems, which analyze both text, photos, or movies in isolation, have established useless at taking pictures multi-modal threats, in which malicious actors spread dangerous content throughout a couple of formats. To cope with these demanding situations, we advise a multi-modal deep mastering framework that integrates Natural Language Processing (NLP), Convolutional Neural Networks (CNNs), and Long Short-Term Memory (LSTM) networks to become aware of and mitigate online threats effectively. Our proposed model combines BERT for text class, ResNet50 for photograph processing, and a hybrid LSTM-3-d CNN community for video content material analysis. We constructed a large-scale dataset comprising 500,000 textual posts, 200,000 offensive images, and 50,000 annotated motion pictures from more than one platform, which includes Twitter, Reddit, YouTube, and online gaming forums. The system became carefully evaluated using trendy gadget mastering metrics which include accuracy, precision, remember, F1-score, and ROC-AUC curves. Experimental outcomes demonstrate that our multi-modal method extensively outperforms single-modal AI classifiers, achieving an accuracy of 92.3%, precision of 91.2%, do not forget of 90.1%, and an AUC rating of 0.95. The findings validate the necessity of integrating multi-modal AI for actual-time, high-accuracy online chance detection and moderation. Future paintings will have consciousness on improving hostile robustness, enhancing scalability for real-world deployment, and addressing ethical worries associated with AI-driven content moderation.展开更多
Our study area covered the Eastern Himalayan Syntaxis (EHS) and its southern extension (Hengduan Mountain or western Sichuan and Yunnan (WSY)) which is located at the orthogonal and oblique collisional front between I...Our study area covered the Eastern Himalayan Syntaxis (EHS) and its southern extension (Hengduan Mountain or western Sichuan and Yunnan (WSY)) which is located at the orthogonal and oblique collisional front between Indian and Asian continents during Cenozoic.Based on geometric and kinematic mapping of the major boundary or regional faults (Dongjug—Mainling(1), Anigiao(2) and Jali(3), Guyu(4) faults in EHS, Ailaoshan—Red River(5), Lancangjiang(6), Gaoligong(7), Binlangjiang(8) and Magok(9) faults in WSY) (see Fig.1), especially on abundant geochronological dating of the mylonitic rocks along these faults, and coupled with magmato\|metamorphic sequences of this region, we try to deal with the temporal and spatial relationships of collisional process to answer questions such as: (1) when did collision start ? (2) is thrusting as a initial and dominant deformation mode to absorb the crustal shortening after suturing, or earlier thrusting usually followed by large\|scale strike\|slip faults? (3) are the two structural patterns coeval at times, or do they occur alternatively during deformation history? (4) are the collisional and associate uplift processes a continuous one or periodic? Insight into such questions is crucial for better understanding of the continental deformation and testing the models available or constraining a new one.展开更多
The multi-factor recombination and processes superimposition model for hydrocarbon accumulation is put forward in view of the hydrocarbon geological characteristics of multiple episodes of structural evolution, multip...The multi-factor recombination and processes superimposition model for hydrocarbon accumulation is put forward in view of the hydrocarbon geological characteristics of multiple episodes of structural evolution, multiple sets of source-reservoir-seal assemblage, multiple cycles of hydrocarbon accumulation and multiple episodes of readjustment and reconstruction in the complex superimposed basins in China. It is a system including theories and methods that can help to predict favorable exploration regions. According to this model, the basic discipline for hydrocarbon generation, evolution and distribution in the superimposed basins can be summarized in multi-factor recombination, processes superimposition, multiple stages of oil filling and latest stage preservation. With the Silurian of the Tarim basin as an example, based on the reconstruction of the evolution history of the four factors （paleo-anticline, source rock, regional cap rock and kinematic equilibrium belt） controlling hydrocarbon accumulation, this model was adopted to predict favorable hydrocarbon accumulation areas and favorable exploration regions following structural destruction in three stages of oil filling, to provide guidance for further exploration ofoil and gas in the Silurian of the Tarim basin.展开更多
Multi-objective optimization has been increasingly applied in engineering where optimal decisions need to be made in the presence of trade-offs between two or more objectives. Minimizing the volume of shrinkage porosi...Multi-objective optimization has been increasingly applied in engineering where optimal decisions need to be made in the presence of trade-offs between two or more objectives. Minimizing the volume of shrinkage porosity, while reducing the secondary dendritic arm spacing of a wheel casting during low-pressure die casting(LPDC) process, was taken as an example of such problem. A commercial simulation software Pro CASTTM was applied to simulate the filling and solidification processes. Additionally, a program for integrating the optimization algorithm with numerical simulation was developed based on SiPESC. By setting pouring temperature and filling pressure as design variables, shrinkage porosity and secondary dendritic arm spacing as objective variables, the multi-objective optimization of minimum volume of shrinkage porosity and secondary dendritic arm spacing was achieved. The optimal combination of AZ91 D wheel casting was: pouring temperature 689 °C and filling pressure 6.5 kPa. The predicted values decreased from 4.1% to 2.1% for shrinkage porosity, and 88.5 μm to 81.2 μm for the secondary dendritic arm spacing. The optimal results proved the feasibility of the developed program in multi-objective optimization.展开更多
The aluminum alloy parts used in airbag of car were studied with flow control forming(FCF) method, which was a good way to low forming force and better mechanical properties. The key technology of FCF was the design o...The aluminum alloy parts used in airbag of car were studied with flow control forming(FCF) method, which was a good way to low forming force and better mechanical properties. The key technology of FCF was the design of control chamber to divide metal flow. So, the design method of FCF was analyzed and two type of control chamber were put forward. According to divisional principle, calculation model of forming force and approximate formula were given. Then forming process of aluminum alloy multi-layer cylinder parts was simulated. The effect of friction factor, die radius and punch velocity on metal flow and forming force was obtained. Finally, the experiment was preformed under the direction of theory and finite element(FE) simulation results. And the qualified parts were manufactured. The simulation data and experimental results show that the forming sequence of inner wall and outer wall, and then the force step, can be controlled by adjusting the process parameters. And the FCF technology proposed has very important application value in precision forging.展开更多
The influence of overlap multi-pass friction stir processing on the microstructure and the mechanical properties, in particular, strength, ductility and hardness of die cast A1-7Si-3Cu aluminum alloy was investigated....The influence of overlap multi-pass friction stir processing on the microstructure and the mechanical properties, in particular, strength, ductility and hardness of die cast A1-7Si-3Cu aluminum alloy was investigated. It was observed that increase in the number of overlap passes friction stir processing resulted in significant refinement and redistribution of aluminum silicon eutectic phase and elimination of casting porosities. The microstructural refinement by the friction stir processing not only increases the ultimate tensile strength from 121 to 273 MPa, but also increases the ductility as observed by the increase in fracture strain from 1.8% to 10%. Analysis of the fractured surface reveals that the microstructural refinement obtained by friction stir processing plays a vital role in transforming the fracture mode from completely mixed mode to the ductile mode of the fracture with increasing number of passes. The change in the size, shape, morphology and distribution of eutectic silicon particles and elimination of the porosities are the main reasons for the increases in tensile strength and ductility due to friction stir processing.展开更多
Simulating charged particle motion through the elements is necessary to understand modern particle accelerators. The particle numbers and the circling turns in a synchrotron are huge, and a simulation can be timeconsu...Simulating charged particle motion through the elements is necessary to understand modern particle accelerators. The particle numbers and the circling turns in a synchrotron are huge, and a simulation can be timeconsuming. Open multi-processing(Open MP) is a convenient method to speed up the computing of multi-cores for computers based on share memory model. Using message passing interface(MPI) which is based on nonuniform memory access architecture, a coarse grain parallel algorithm is set up for the Accelerator Toolbox(AT)for dynamic tracking processes. The computing speedup of the tracking process is 3.77 times with a quad-core CPU computer and the speed almost grows linearly with the number of CPU.展开更多
In this paper, we study a new version from Dual-pivot Quicksort algorithm when we have some other number of pivots. Hence, we discuss the idea of picking pivots ?by random way and splitting the list simultaneously acc...In this paper, we study a new version from Dual-pivot Quicksort algorithm when we have some other number of pivots. Hence, we discuss the idea of picking pivots ?by random way and splitting the list simultaneously according to these. The modified version generalizes these results for multi process. We show that the average number of swaps done by Multi-pivot Quicksort process and we present a special case. Moreover, we obtain a relationship between the average number of swaps of Multi-pivot Quicksort and Stirling numbers of the first kind.展开更多
A distributed process planning system based on autonomous multi agent system to solve a distributed process plan task in a manufacturing environment was presented. A distributed agent based process plan structure was ...A distributed process planning system based on autonomous multi agent system to solve a distributed process plan task in a manufacturing environment was presented. A distributed agent based process plan structure was shown to be a viable alternative to hierarchical systems providing real time response to shop floor condition. An outline was done to show how to structure a distributed process plan and how its management may be achieved among manufacturers of parts that form a product. Communication between the agents involved in a distributed process planning was also shown to be important, with the controlling agent having an overall supervision of the plans. Based on the reference model a software tool was developed to realize it.展开更多
In this paper, the modelling and multi-objective optimal control of batch processes, using a recurrent neuro-fuzzy network, are presented. The recurrent neuro-fuzzy network, forms a ＂global＂ nonlinear long-range pre...In this paper, the modelling and multi-objective optimal control of batch processes, using a recurrent neuro-fuzzy network, are presented. The recurrent neuro-fuzzy network, forms a ＂global＂ nonlinear long-range prediction model through the fuzzy conjunction of a number of ＂local＂ linear dynamic models. Network output is fed back to network input through one or more time delay units, which ensure that predictions from the recurrent neuro-fuzzy network are long-range. In building a recurrent neural network model, process knowledge is used initially to partition the processes non-linear characteristics into several local operating regions, and to aid in the initialisation of corresponding network weights. Process operational data is then used to train the network. Membership functions of the local regimes are identified, and local models are discovered via network training. Based on a recurrent neuro-fuzzy network model, a multi-objective optimal control policy can be obtained. The proposed technique is applied to a fed-batch reactor.展开更多
This paper deals with a multi-objective parameter optimization framework for energy saving in injection molding process.It combines an experimental design by Taguchi's method,a process analysis by analysis of vari...This paper deals with a multi-objective parameter optimization framework for energy saving in injection molding process.It combines an experimental design by Taguchi's method,a process analysis by analysis of variance(ANOVA),a process modeling algorithm by artificial neural network(ANN),and a multi-objective parameter optimization algorithm by genetic algorithm(GA)-based lexicographic method.Local and global Pareto analyses show the trade-off between product quality and energy consumption.The implementation of the proposed framework can reduce the energy consumption significantly in laboratory scale tests,and at the same time,the product quality can meet the pre-determined requirements.展开更多
In this paper, we introduce the definition of a multi-parameter fractional Lévy process and its local time, and show its decomposition. Using the decomposition, we prove existence and joint continuity of its loca...In this paper, we introduce the definition of a multi-parameter fractional Lévy process and its local time, and show its decomposition. Using the decomposition, we prove existence and joint continuity of its local time.展开更多
The surface of copper-chromium alloy was processed by Al-Si-Ni multi-permeation and friction stir processing,and the microstructure and mechanical properties of the surface layer were tested by scanning electron micro...The surface of copper-chromium alloy was processed by Al-Si-Ni multi-permeation and friction stir processing,and the microstructure and mechanical properties of the surface layer were tested by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),microhardness tester and friction testing machine.The results show that Al,Si and Ni elements are fully permeated into the surface of copper-chromium alloy after multielement co-infiltration and friction stir processing.In the observation of the microstructures,we found that the reticular structure is fragmented and distributed in the stir zone region.Microstructure becomes finer and grains refinement.The micro hardness of the copper-chromium alloy increased to 129 HV,44.9%higher than that of the original matrix.The main reasons of microhardness enhancement are solid solution strengthening,fine grains strengthening and dispersion strengthening.The friction test results show that the friction coefficient is basically stable at 0.69 and the wear mass is only 0.0017 g after 10 min of friction test.The improvement of wear resistance was attributed to the increase of microhardness of the alloy surface.展开更多
Influence of core property on multi-electron process in the collisions of q = 6-9 and 11 isocharged sequence ions with Ne is investigated in the keV/u region. The cross-section ratios of double-, triple-, quadruple- a...Influence of core property on multi-electron process in the collisions of q = 6-9 and 11 isocharged sequence ions with Ne is investigated in the keV/u region. The cross-section ratios of double-, triple-, quadruple- and total multielectron processes to the single electron capture process as well as the partial ratios of different reaction channels to the relevant multi-electron process are measured by using position-sensitive and time-of-flight techniques. The experimental data are compared with the theoretical predictions including the extended classical over-barrier model, the molecular Columbic barrier model and the semi-empirical scaling law. Results show a core effect on multi-electron process of isocharge ions colliding with Neon, which is consistent with the results of Helium we obtained previously.展开更多
A multi-scale numerical method coupled with the reactor,sheath and trench model is constructed to simulate dry etching of SiO_2 in inductively coupled C_4F_8 plasmas.Firstly,ion and neutral particle densities in the r...A multi-scale numerical method coupled with the reactor,sheath and trench model is constructed to simulate dry etching of SiO_2 in inductively coupled C_4F_8 plasmas.Firstly,ion and neutral particle densities in the reactor are decided using the CFD-ACE＋ commercial software.Then,the ion energy and angular distributions（IEDs and IADs） are obtained in the sheath model with the sheath boundary conditions provided with CFD-ACE＋.Finally,the trench profile evolution is simulated in the trench model.What we principally focus on is the effects of the discharge parameters on the etching results.It is found that the discharge parameters,including discharge pressure,radio-frequency（rf） power,gas mixture ratios,bias voltage and frequency,have synergistic effects on IEDs and IADs on the etched material surface,thus further affecting the trench profiles evolution.展开更多
To prevent the long-time coherent integration and limited range window stumbling blocks of stretch processing and reduce computational complexity, a novel method called multi-subpulse process of large time-bandwidth p...To prevent the long-time coherent integration and limited range window stumbling blocks of stretch processing and reduce computational complexity, a novel method called multi-subpulse process of large time-bandwidth product linear frequency modulating （ LFM ） signal （ i. e. chirp ） is proposed in this paper. The wideband chirp signal is split up into several compressed subpulses. Then the fast Fourier transform （FFT） is used to reconstruct the high resolution range profile （ HR- RP） in a relative short computation time. For multi-frame, pulse Doppler （PD） process is performed to obtain the two-dimension range-Doppler （R-D） high resolution profile. Simulations and field ex- perimental results show that the proposed method can provide high-quality target profile over a large range window in a short computation time and has the promising potential for long-time coherent in- tegration.展开更多
Aiming to share the information,knowledge and optimizing resource via collaborating with multiple external partners across their supply chains,the concept model and system framework of multi-enterprises collaborative ...Aiming to share the information,knowledge and optimizing resource via collaborating with multiple external partners across their supply chains,the concept model and system framework of multi-enterprises collaborative resource planning (MECORP) are put forward.While there is Considerable pressure to improve the operation of MECORP system,their inherent complexity can make modelling a MECORP system a difficult task.Yet there could be considerable benefits in designing MECORP taking into account the operation of the system.In order to address the central research issue of developing of a methodology that can assist a manager in making decisions by modelling the operation of MECORP system.The methodology called process-oriented deci- sion model (PODM) is presented in the paper.This uses an abstracted network to model MECORP system.The MECORP system supported by PODM,can effective optimize the manifold resource,coordinate the relationship of multiple partners and assist deci- sion.Finally,an industry excample of MECORP system is described to illustrate the application of PODM.展开更多
Multi-scales relaxation processes of short fiber of a nematic liquid crystalline copolymer(LCP)in polycarbonate matrix were investigated.First,the structure relaxation of LCP was studied by rheology.The relaxation spe...Multi-scales relaxation processes of short fiber of a nematic liquid crystalline copolymer(LCP)in polycarbonate matrix were investigated.First,the structure relaxation of LCP was studied by rheology.The relaxation spectrum of the nematic liquid crystalline copolymer at 295℃was calculated from the combined dynamic modulus.There are three kinds of relaxation mechanisms for nematic liquid crystalline copotymer:the relaxation of chain orientation,the relaxation of deformed polydomains and the coalescence of pol...展开更多
Based on activity calculation model, the activity coefficients of Ti, Al and Nb components of Ti 25Al 25Nb (mole fraction, %) melt, the vapor pressures of corresponding components and the evaporation loss rates were c...Based on activity calculation model, the activity coefficients of Ti, Al and Nb components of Ti 25Al 25Nb (mole fraction, %) melt, the vapor pressures of corresponding components and the evaporation loss rates were calculated. Utilizing these activity coefficients and the vapor pressures, the relative evaporation coefficient is used to judge the evaporation tendency of these components. The evaporation tendency among the three components were compared and the result shows that the evaporation tendency is that: AlTi>Nb. Evaporation loss rate increases with the increase of melting temperature and decreases with the increase of chamber pressure. There exists an impeding pressure p impe of Al element evaporation during induction skull melting process of Ti 25Al 25Nb alloy. The impeding pressure can be written as p impe =8.1 p e, where p e represents the equilibrium partial pressure. The calculation of evaporation loss of Al element also showed that when chamber pressure exceeds p impe , the Al volatilization losses could be ignored. In order to prevent the evaporation loss of components, the pressure in the vacuum chamber should not below p impe .展开更多
The design of reconfigurable multi-butterfly parallel radix-r FFT (Fast Fourier Transform) processors is proposed. FFT is widely used in signal processing, and the application needs real-time and high performance, whi...The design of reconfigurable multi-butterfly parallel radix-r FFT (Fast Fourier Transform) processors is proposed. FFT is widely used in signal processing, and the application needs real-time and high performance, while most of the traditional designs are limited to the power of two, which wastes the buffers and multipliers in big data. In response to the problem, we improve the parallel FFT algorithm with the design of reconfigurable control machine combined with buffer/multiplier, and the cost function with the input of radix/number/paddling number/time consuming is deduced. Constrained with the number of buffer and multipliers, the radix and number can be computed with the optimum cost function, and the resolution space of computing performance and hardware cost is presented. The proposed guarantees the real-time performance with better flexibility compared with the previous literature, and the comparison also suggests the effectiveness of the design.展开更多
文摘The fast increase of online communities has brought about an increase in cyber threats inclusive of cyberbullying, hate speech, misinformation, and online harassment, making content moderation a pressing necessity. Traditional single-modal AI-based detection systems, which analyze both text, photos, or movies in isolation, have established useless at taking pictures multi-modal threats, in which malicious actors spread dangerous content throughout a couple of formats. To cope with these demanding situations, we advise a multi-modal deep mastering framework that integrates Natural Language Processing (NLP), Convolutional Neural Networks (CNNs), and Long Short-Term Memory (LSTM) networks to become aware of and mitigate online threats effectively. Our proposed model combines BERT for text class, ResNet50 for photograph processing, and a hybrid LSTM-3-d CNN community for video content material analysis. We constructed a large-scale dataset comprising 500,000 textual posts, 200,000 offensive images, and 50,000 annotated motion pictures from more than one platform, which includes Twitter, Reddit, YouTube, and online gaming forums. The system became carefully evaluated using trendy gadget mastering metrics which include accuracy, precision, remember, F1-score, and ROC-AUC curves. Experimental outcomes demonstrate that our multi-modal method extensively outperforms single-modal AI classifiers, achieving an accuracy of 92.3%, precision of 91.2%, do not forget of 90.1%, and an AUC rating of 0.95. The findings validate the necessity of integrating multi-modal AI for actual-time, high-accuracy online chance detection and moderation. Future paintings will have consciousness on improving hostile robustness, enhancing scalability for real-world deployment, and addressing ethical worries associated with AI-driven content moderation.
文摘Our study area covered the Eastern Himalayan Syntaxis (EHS) and its southern extension (Hengduan Mountain or western Sichuan and Yunnan (WSY)) which is located at the orthogonal and oblique collisional front between Indian and Asian continents during Cenozoic.Based on geometric and kinematic mapping of the major boundary or regional faults (Dongjug—Mainling(1), Anigiao(2) and Jali(3), Guyu(4) faults in EHS, Ailaoshan—Red River(5), Lancangjiang(6), Gaoligong(7), Binlangjiang(8) and Magok(9) faults in WSY) (see Fig.1), especially on abundant geochronological dating of the mylonitic rocks along these faults, and coupled with magmato\|metamorphic sequences of this region, we try to deal with the temporal and spatial relationships of collisional process to answer questions such as: (1) when did collision start ? (2) is thrusting as a initial and dominant deformation mode to absorb the crustal shortening after suturing, or earlier thrusting usually followed by large\|scale strike\|slip faults? (3) are the two structural patterns coeval at times, or do they occur alternatively during deformation history? (4) are the collisional and associate uplift processes a continuous one or periodic? Insight into such questions is crucial for better understanding of the continental deformation and testing the models available or constraining a new one.
文摘The multi-factor recombination and processes superimposition model for hydrocarbon accumulation is put forward in view of the hydrocarbon geological characteristics of multiple episodes of structural evolution, multiple sets of source-reservoir-seal assemblage, multiple cycles of hydrocarbon accumulation and multiple episodes of readjustment and reconstruction in the complex superimposed basins in China. It is a system including theories and methods that can help to predict favorable exploration regions. According to this model, the basic discipline for hydrocarbon generation, evolution and distribution in the superimposed basins can be summarized in multi-factor recombination, processes superimposition, multiple stages of oil filling and latest stage preservation. With the Silurian of the Tarim basin as an example, based on the reconstruction of the evolution history of the four factors （paleo-anticline, source rock, regional cap rock and kinematic equilibrium belt） controlling hydrocarbon accumulation, this model was adopted to predict favorable hydrocarbon accumulation areas and favorable exploration regions following structural destruction in three stages of oil filling, to provide guidance for further exploration ofoil and gas in the Silurian of the Tarim basin.
基金financially supported by the National Key Research and Development Program of China(Grant No.2016YFB0701204)
文摘Multi-objective optimization has been increasingly applied in engineering where optimal decisions need to be made in the presence of trade-offs between two or more objectives. Minimizing the volume of shrinkage porosity, while reducing the secondary dendritic arm spacing of a wheel casting during low-pressure die casting(LPDC) process, was taken as an example of such problem. A commercial simulation software Pro CASTTM was applied to simulate the filling and solidification processes. Additionally, a program for integrating the optimization algorithm with numerical simulation was developed based on SiPESC. By setting pouring temperature and filling pressure as design variables, shrinkage porosity and secondary dendritic arm spacing as objective variables, the multi-objective optimization of minimum volume of shrinkage porosity and secondary dendritic arm spacing was achieved. The optimal combination of AZ91 D wheel casting was: pouring temperature 689 °C and filling pressure 6.5 kPa. The predicted values decreased from 4.1% to 2.1% for shrinkage porosity, and 88.5 μm to 81.2 μm for the secondary dendritic arm spacing. The optimal results proved the feasibility of the developed program in multi-objective optimization.
文摘The aluminum alloy parts used in airbag of car were studied with flow control forming(FCF) method, which was a good way to low forming force and better mechanical properties. The key technology of FCF was the design of control chamber to divide metal flow. So, the design method of FCF was analyzed and two type of control chamber were put forward. According to divisional principle, calculation model of forming force and approximate formula were given. Then forming process of aluminum alloy multi-layer cylinder parts was simulated. The effect of friction factor, die radius and punch velocity on metal flow and forming force was obtained. Finally, the experiment was preformed under the direction of theory and finite element(FE) simulation results. And the qualified parts were manufactured. The simulation data and experimental results show that the forming sequence of inner wall and outer wall, and then the force step, can be controlled by adjusting the process parameters. And the FCF technology proposed has very important application value in precision forging.
文摘The influence of overlap multi-pass friction stir processing on the microstructure and the mechanical properties, in particular, strength, ductility and hardness of die cast A1-7Si-3Cu aluminum alloy was investigated. It was observed that increase in the number of overlap passes friction stir processing resulted in significant refinement and redistribution of aluminum silicon eutectic phase and elimination of casting porosities. The microstructural refinement by the friction stir processing not only increases the ultimate tensile strength from 121 to 273 MPa, but also increases the ductility as observed by the increase in fracture strain from 1.8% to 10%. Analysis of the fractured surface reveals that the microstructural refinement obtained by friction stir processing plays a vital role in transforming the fracture mode from completely mixed mode to the ductile mode of the fracture with increasing number of passes. The change in the size, shape, morphology and distribution of eutectic silicon particles and elimination of the porosities are the main reasons for the increases in tensile strength and ductility due to friction stir processing.
基金Supported by the National Natural Science Foundation of China(No11105214)
文摘Simulating charged particle motion through the elements is necessary to understand modern particle accelerators. The particle numbers and the circling turns in a synchrotron are huge, and a simulation can be timeconsuming. Open multi-processing(Open MP) is a convenient method to speed up the computing of multi-cores for computers based on share memory model. Using message passing interface(MPI) which is based on nonuniform memory access architecture, a coarse grain parallel algorithm is set up for the Accelerator Toolbox(AT)for dynamic tracking processes. The computing speedup of the tracking process is 3.77 times with a quad-core CPU computer and the speed almost grows linearly with the number of CPU.
文摘In this paper, we study a new version from Dual-pivot Quicksort algorithm when we have some other number of pivots. Hence, we discuss the idea of picking pivots ?by random way and splitting the list simultaneously according to these. The modified version generalizes these results for multi process. We show that the average number of swaps done by Multi-pivot Quicksort process and we present a special case. Moreover, we obtain a relationship between the average number of swaps of Multi-pivot Quicksort and Stirling numbers of the first kind.
文摘A distributed process planning system based on autonomous multi agent system to solve a distributed process plan task in a manufacturing environment was presented. A distributed agent based process plan structure was shown to be a viable alternative to hierarchical systems providing real time response to shop floor condition. An outline was done to show how to structure a distributed process plan and how its management may be achieved among manufacturers of parts that form a product. Communication between the agents involved in a distributed process planning was also shown to be important, with the controlling agent having an overall supervision of the plans. Based on the reference model a software tool was developed to realize it.
基金This work was supported by the UK EPSRC (GR/N13319, GR/R10875).
文摘In this paper, the modelling and multi-objective optimal control of batch processes, using a recurrent neuro-fuzzy network, are presented. The recurrent neuro-fuzzy network, forms a ＂global＂ nonlinear long-range prediction model through the fuzzy conjunction of a number of ＂local＂ linear dynamic models. Network output is fed back to network input through one or more time delay units, which ensure that predictions from the recurrent neuro-fuzzy network are long-range. In building a recurrent neural network model, process knowledge is used initially to partition the processes non-linear characteristics into several local operating regions, and to aid in the initialisation of corresponding network weights. Process operational data is then used to train the network. Membership functions of the local regimes are identified, and local models are discovered via network training. Based on a recurrent neuro-fuzzy network model, a multi-objective optimal control policy can be obtained. The proposed technique is applied to a fed-batch reactor.
基金(Nos. 20806040,61073059 and 61034005) supported by the National Natural Science Foundation of China
文摘This paper deals with a multi-objective parameter optimization framework for energy saving in injection molding process.It combines an experimental design by Taguchi's method,a process analysis by analysis of variance(ANOVA),a process modeling algorithm by artificial neural network(ANN),and a multi-objective parameter optimization algorithm by genetic algorithm(GA)-based lexicographic method.Local and global Pareto analyses show the trade-off between product quality and energy consumption.The implementation of the proposed framework can reduce the energy consumption significantly in laboratory scale tests,and at the same time,the product quality can meet the pre-determined requirements.
基金supported by the National Natural Science Foundation of China (No. 10871177)the Ph. D.Programs Foundation of Ministry of Education of China (No. 20060335032)the Natural Science Foundation of Zhejiang Province of China (No. Y7080044)
文摘In this paper, we introduce the definition of a multi-parameter fractional Lévy process and its local time, and show its decomposition. Using the decomposition, we prove existence and joint continuity of its local time.
基金financial support from the National Natural Science Foundation of China (No. 51571214)Science Project of Shenzhen (JCYJ20180508151903646)
文摘The surface of copper-chromium alloy was processed by Al-Si-Ni multi-permeation and friction stir processing,and the microstructure and mechanical properties of the surface layer were tested by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),microhardness tester and friction testing machine.The results show that Al,Si and Ni elements are fully permeated into the surface of copper-chromium alloy after multielement co-infiltration and friction stir processing.In the observation of the microstructures,we found that the reticular structure is fragmented and distributed in the stir zone region.Microstructure becomes finer and grains refinement.The micro hardness of the copper-chromium alloy increased to 129 HV,44.9%higher than that of the original matrix.The main reasons of microhardness enhancement are solid solution strengthening,fine grains strengthening and dispersion strengthening.The friction test results show that the friction coefficient is basically stable at 0.69 and the wear mass is only 0.0017 g after 10 min of friction test.The improvement of wear resistance was attributed to the increase of microhardness of the alloy surface.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10874188 and 10775160)
文摘Influence of core property on multi-electron process in the collisions of q = 6-9 and 11 isocharged sequence ions with Ne is investigated in the keV/u region. The cross-section ratios of double-, triple-, quadruple- and total multielectron processes to the single electron capture process as well as the partial ratios of different reaction channels to the relevant multi-electron process are measured by using position-sensitive and time-of-flight techniques. The experimental data are compared with the theoretical predictions including the extended classical over-barrier model, the molecular Columbic barrier model and the semi-empirical scaling law. Results show a core effect on multi-electron process of isocharge ions colliding with Neon, which is consistent with the results of Helium we obtained previously.
基金supported by National Natural Science Foundation of China(No.11375040)the Important National Science&Technology Specific Project of China(No.2011ZX02403-002)
文摘A multi-scale numerical method coupled with the reactor,sheath and trench model is constructed to simulate dry etching of SiO_2 in inductively coupled C_4F_8 plasmas.Firstly,ion and neutral particle densities in the reactor are decided using the CFD-ACE＋ commercial software.Then,the ion energy and angular distributions（IEDs and IADs） are obtained in the sheath model with the sheath boundary conditions provided with CFD-ACE＋.Finally,the trench profile evolution is simulated in the trench model.What we principally focus on is the effects of the discharge parameters on the etching results.It is found that the discharge parameters,including discharge pressure,radio-frequency（rf） power,gas mixture ratios,bias voltage and frequency,have synergistic effects on IEDs and IADs on the etched material surface,thus further affecting the trench profiles evolution.
基金Supported by the National Natural Science Foundation of China(61301189)
文摘To prevent the long-time coherent integration and limited range window stumbling blocks of stretch processing and reduce computational complexity, a novel method called multi-subpulse process of large time-bandwidth product linear frequency modulating （ LFM ） signal （ i. e. chirp ） is proposed in this paper. The wideband chirp signal is split up into several compressed subpulses. Then the fast Fourier transform （FFT） is used to reconstruct the high resolution range profile （ HR- RP） in a relative short computation time. For multi-frame, pulse Doppler （PD） process is performed to obtain the two-dimension range-Doppler （R-D） high resolution profile. Simulations and field ex- perimental results show that the proposed method can provide high-quality target profile over a large range window in a short computation time and has the promising potential for long-time coherent in- tegration.
文摘Aiming to share the information,knowledge and optimizing resource via collaborating with multiple external partners across their supply chains,the concept model and system framework of multi-enterprises collaborative resource planning (MECORP) are put forward.While there is Considerable pressure to improve the operation of MECORP system,their inherent complexity can make modelling a MECORP system a difficult task.Yet there could be considerable benefits in designing MECORP taking into account the operation of the system.In order to address the central research issue of developing of a methodology that can assist a manager in making decisions by modelling the operation of MECORP system.The methodology called process-oriented deci- sion model (PODM) is presented in the paper.This uses an abstracted network to model MECORP system.The MECORP system supported by PODM,can effective optimize the manifold resource,coordinate the relationship of multiple partners and assist deci- sion.Finally,an industry excample of MECORP system is described to illustrate the application of PODM.
基金This work was financially supported by the National Natural Science Foundation of China(Nos. 20174024,20204007 and 50290090).
文摘Multi-scales relaxation processes of short fiber of a nematic liquid crystalline copolymer(LCP)in polycarbonate matrix were investigated.First,the structure relaxation of LCP was studied by rheology.The relaxation spectrum of the nematic liquid crystalline copolymer at 295℃was calculated from the combined dynamic modulus.There are three kinds of relaxation mechanisms for nematic liquid crystalline copotymer:the relaxation of chain orientation,the relaxation of deformed polydomains and the coalescence of pol...
文摘Based on activity calculation model, the activity coefficients of Ti, Al and Nb components of Ti 25Al 25Nb (mole fraction, %) melt, the vapor pressures of corresponding components and the evaporation loss rates were calculated. Utilizing these activity coefficients and the vapor pressures, the relative evaporation coefficient is used to judge the evaporation tendency of these components. The evaporation tendency among the three components were compared and the result shows that the evaporation tendency is that: AlTi>Nb. Evaporation loss rate increases with the increase of melting temperature and decreases with the increase of chamber pressure. There exists an impeding pressure p impe of Al element evaporation during induction skull melting process of Ti 25Al 25Nb alloy. The impeding pressure can be written as p impe =8.1 p e, where p e represents the equilibrium partial pressure. The calculation of evaporation loss of Al element also showed that when chamber pressure exceeds p impe , the Al volatilization losses could be ignored. In order to prevent the evaporation loss of components, the pressure in the vacuum chamber should not below p impe .
文摘The design of reconfigurable multi-butterfly parallel radix-r FFT (Fast Fourier Transform) processors is proposed. FFT is widely used in signal processing, and the application needs real-time and high performance, while most of the traditional designs are limited to the power of two, which wastes the buffers and multipliers in big data. In response to the problem, we improve the parallel FFT algorithm with the design of reconfigurable control machine combined with buffer/multiplier, and the cost function with the input of radix/number/paddling number/time consuming is deduced. Constrained with the number of buffer and multipliers, the radix and number can be computed with the optimum cost function, and the resolution space of computing performance and hardware cost is presented. The proposed guarantees the real-time performance with better flexibility compared with the previous literature, and the comparison also suggests the effectiveness of the design.
