We conduct a theoretical analysis of the massive and tunable Goos–Hänchen(GH) shift on a polar crystal covered with periodical black phosphorus(BP)-patches in the THz range. The surface plasmon phonon polaritons...We conduct a theoretical analysis of the massive and tunable Goos–Hänchen(GH) shift on a polar crystal covered with periodical black phosphorus(BP)-patches in the THz range. The surface plasmon phonon polaritons(SPPPs), which are coupled by the surface phonon polaritons(SPh Ps) and surface plasmon polaritons(SPPs), can greatly increase GH shifts.Based on the in-plane anisotropy of BP, two typical metasurface models are designed and investigated. An enormous GH shift of about-7565.58 λ_(0) is achieved by adjusting the physical parameters of the BP-patches. In the designed metasurface structure, the maximum sensitivity accompanying large GH shifts can reach about 6.43 × 10^(8) λ_(0)/RIU, which is extremely sensitive to the size, carrier density, and layer number of BP. Compared with a traditional surface plasmon resonance sensor, the sensitivity is increased by at least two orders of magnitude. We believe that investigating metasurface-based SPPPs sensors could lead to high-sensitivity biochemical detection applications.展开更多
Water jet technology is widely used in submerged buried pipes as a non-traditional trenching process,often invol-ving a complex sediment response.An important adjustable and influential engineering variable in this tec...Water jet technology is widely used in submerged buried pipes as a non-traditional trenching process,often invol-ving a complex sediment response.An important adjustable and influential engineering variable in this technol-ogy is represented by the impinging distance.In this study,the FLOW-3D software was used to simulate the jet scouring of sand beds in a submerged environment.In particular,four sets of experimental conditions were con-sidered to discern the relationship between the maximum scour depth and mass and the impinging distance.As shown by the results,a critical impinging distance h0 exists by which the static scour depth can be maximized;the scour mass ratio between dynamic and static conditions decreases as the impinging distance increases.Moreover,the profile contours are similar when the erosion parameter Ec is in the range 0.35<Ec<2.Empirical equations applicable for predicting the jet trenching contour under both dynamic and static scour modes are also provided in this study.展开更多
Scouring experiments were conducted using a three-dimensional laser scanning technology for angles of the jet spanning the interval from 0°to 30°,and the characteristics of the scour hole in equilibrium cond...Scouring experiments were conducted using a three-dimensional laser scanning technology for angles of the jet spanning the interval from 0°to 30°,and the characteristics of the scour hole in equilibrium conditions were investigated accordingly.The results indicate that the optimal scouring effects occur when the jet angle is in the ranges between 15°and 20°.Moreover,the dimensionless profiles of the scour hole exhibit a high degree of similarity at different jet angles.Numerical simulations conducted using the Flow-3D software to investigate the bed shear stress along the jet impingement surface have shown that this stress is influenced by both the resultant force and the jet impingement surface area.It reaches its maximum value when the jet is vertical,decreases rapidly as the jet starts to tilt,then increases slightly,and decreases again significantly when the angle exceeds 20°.展开更多
Water jets are widely used in seabed scouring and desilting applications.In the present work,dedicated tests have been conducted using a jet scour model test platform and sand beds containing grains with different siz...Water jets are widely used in seabed scouring and desilting applications.In the present work,dedicated tests have been conducted using a jet scour model test platform and sand beds containing grains with different sizes.The FLOW-3D simulation software has also been used to tackle the problem form a numerical point of view.The boundary conditions of the simulation have been optimized to reduce the gap between the numerical results and the outcomes of the experimental tests.Scour area calculation has been based on a RNG k-εTurbulence model.Moreover,the FAVOR(Fractional Area Volume Obstacle Representation)technology has been selected for grid division to make the simulation results more accurate.Jet scours with inclination angles of 10–20°have been simulated.It has been found that jet scouring is greatly affected by the environmental water flow,that is,water flow can weaken the scouring capacity of the jets.展开更多
The effects of oblique submerged scouring jets on sand beds with various particle sizes have been studied experimentally.In particular,a total of 25 experiments have been carried out to explore the influences of the j...The effects of oblique submerged scouring jets on sand beds with various particle sizes have been studied experimentally.In particular,a total of 25 experiments have been carried out to explore the influences of the jet angle and application time on the considered submerged sand beds.Test results conducted with a specially-designed device have shown that the scouring efficiency attains a maximum when the inclination angle is in the range between 15°and 20°and then it decreases when the inclination angle becomes higher.展开更多
Aimed at the hydrodynamic response for marine structures slamming into water, based on the mechanism analysis to the slamming process, and by combining 3D N-S equation and k-ε turbulent kinetic equation with structur...Aimed at the hydrodynamic response for marine structures slamming into water, based on the mechanism analysis to the slamming process, and by combining 3D N-S equation and k-ε turbulent kinetic equation with structure fully 6DOF motion equation, a mathematical model for the wind-fluid-solid interaction is established in 3D marine structure slamming wave at free poses and wind-wave-flow complex environments. Compared with the results of physical model test, the numerical results from the slamming wave well correspond with the experimental results. Through the mathematical model, the wave-making issue of 3D marine structure at initial pose falls into water in different complex wind, wave and flow environments is investigated. The research results show that various kinds of natural factors and structure initial poses have different influence on the slamming wave, and there is an obvious rule in this process.展开更多
The theory of integration to mathematical analysis is so important that many mathematicians continue to develop new theory to enlarge the class of integrable functions and simplify the Lebesgue theory integration. In ...The theory of integration to mathematical analysis is so important that many mathematicians continue to develop new theory to enlarge the class of integrable functions and simplify the Lebesgue theory integration. In this paper, by slight modifying the definition of the Henstock integral which was introduced by Jaroslav Kurzweil and Ralph Henstock, we present a new definition of integral on fractal sets. Furthermore, its integrability has been discussed, and the relationship between differentiation and integral is also established. As an example, the integral of Cantor function on Cantor set is calculated.展开更多
A game measurement model considering the attacker’s knowledge background is proposed based on the Bayesian game theory aiming at striking a balance between the protection of sensitive information and the quality of s...A game measurement model considering the attacker’s knowledge background is proposed based on the Bayesian game theory aiming at striking a balance between the protection of sensitive information and the quality of service.We quantified the sensitive level of information according to the user’s personalized sensitive information protection needs.Based on the probability distribution of sensitive level and attacker’s knowledge background type,the strategy combination of service provider and attacker was analyzed,and a game-based sensitive information protection model was constructed.Through the combination of strategies under Bayesian equilibrium,the information entropy was used to measure the leakage of sensitive information.Furthermore,in the paper the influence of the sensitive level of information and the attacker’s knowledge background on the strategy of both sides of the game was considered comprehensively.Further on,the leakage of the user’s sensitive information was measured.Finally,the feasibility of the model was described by experiments.展开更多
The economic and social progress under the new era has put forward new requirements for logistics talents.Based on the teaching concept of OBE-CDIO as well as the training program and objectives of logistics managemen...The economic and social progress under the new era has put forward new requirements for logistics talents.Based on the teaching concept of OBE-CDIO as well as the training program and objectives of logistics management major in Guangzhou Maritime University,this study analyzes and discusses how the Logistics System Planning and Design course,which is targeted at students majoring in logistics management,enables the students to meet the graduation requirements by virtue of realizing the course objectives.展开更多
This study analyzes the background of ideological and political theories teaching in operations research courses and provides a design framework for ideological and political theories teaching in operations research c...This study analyzes the background of ideological and political theories teaching in operations research courses and provides a design framework for ideological and political theories teaching in operations research courses based on“trinity”according to real teaching practices.This article summarizes the merging point of ideological and political theories teaching in operations research courses,taking ability and knowledge as its carrier and ideological and political theories teaching as its core,as well as discusses four methods of ideological and political theories teaching:online and offline interactive teaching,stimulating independent learning by practical application,seminar-style flipped classroom,and promoting theoretical teaching through competition and scientific research.展开更多
This article discusses the problems existing in the teaching of Logistics and the urgency of its curriculum reform,introduces the concept of outcome-based education(OBE)into the teaching process of Logistics,designs t...This article discusses the problems existing in the teaching of Logistics and the urgency of its curriculum reform,introduces the concept of outcome-based education(OBE)into the teaching process of Logistics,designs the teaching in a reverse direction guided by the results,and implements the teaching design in the form of flipped classroom.A“student-centered”teaching process endows students with stronger autonomy and initiative and encourages them to cooperate with each other.This teaching process provides new ideas and methods for the teaching reform of Logistics as well as the cultivation of excellent logistics talents.展开更多
This paper proposes a low-rank spectral estimation algorithm of learning Markov model.First,an approximate projection algorithm for the rank-constrained frequency matrix set is proposed,and thereafter its local Lipsch...This paper proposes a low-rank spectral estimation algorithm of learning Markov model.First,an approximate projection algorithm for the rank-constrained frequency matrix set is proposed,and thereafter its local Lipschitzian error bound established.Then,we propose a low-rank spectral estimation algorithm for estimating the state transition frequency matrix and the probability matrix of Markov model by applying the approximate projection algorithm to correct the maximum likelihood estimation of the frequency matrix,and prove that there is only a multiplying constant difference in estimation errors between the low-rank spectral estimation and the maximum likelihood estimation under appropriate conditions.Finally,numerical comparisons with the prevailing maximum likelihood estimation,spectral estimation,and rank-constrained maxi-mum likelihood estimation show that the low-rank spectral estimation algorithm is effective.展开更多
We use the refined hot spot model to study the valence quark shape of the proton with the deeply virtual Compton scattering at high energies in the color glass condensate framework.To investigate the individual valenc...We use the refined hot spot model to study the valence quark shape of the proton with the deeply virtual Compton scattering at high energies in the color glass condensate framework.To investigate the individual valence quark shape,a novel treatment of the valence quark width is employed.We calculate the cross-sections for coherent and incoherent deeply virtual Compton scattering using,for the first time,different widths(Bu and Bd)for the profile density distributions of the up and down quarks instead of using the same width as in the literature.We find that the cross-sections calculated with Bu≥Bd at each collision energy are consistent with each other,which is in agreement with theoretical expectations,whereas those computed with Bu<Bd show some discrepancies.This outcome implies that the up quark might emit more gluons than the down quark,leading to Bu≥Bd at high energy.The impact of energy on the outcome is estimated.Our results show that as the collision energy increases,the aforementioned discrepancies are not only significantly broadened,but also shift to a relatively smaller momentum transfer range at the future Electron-Ion Collider(EIC)and Large Hadron Electron Collider(LHeC)energies,which indicates that the EIC and LHeC can provide an unprecedented chance to access the shape of the valence quark of the proton.展开更多
The space-air-ground integrated networks (SAGIN) has emerged as a critical paradigm to address the growing demands for global connectivity and enhanced communication services. This paper gives a thorough review of the...The space-air-ground integrated networks (SAGIN) has emerged as a critical paradigm to address the growing demands for global connectivity and enhanced communication services. This paper gives a thorough review of the strategies and methodologies for resource allocation within SAGIN, focusing on the challenges and solutions within its complex structure. With the advent of technologies such as 6G, the dynamics of resource optimization have become increasingly complex, necessitating innovative approaches for efficient management. We examine the application of mathematical optimization, game theory, artificial intelligence (AI), and dynamic optimization techniques in SAGIN,offering insights into their effectiveness in ensuring optimal resource distribution, minimizing delays, and maximizing network throughput and stability. The survey highlights the significant advances in AI-based methods,particularly deep learning and reinforcement learning, in tackling the inherent challenges of SAGIN resource allocation. Through a critical review of existing literature, this paper categorizes various resource allocation strategies, identifies current research gaps, and discusses potential future directions. Our findings highlight the crucial role of integrated and intelligent resource allocation mechanisms in realizing the full potential of SAGIN for next-generation communication networks.展开更多
This paper proposes an online power system voltage stability index(PVSI Online)that quantifies power system voltage stability in real time between an AC network and LCC HVDC using only local measurements.Previous meth...This paper proposes an online power system voltage stability index(PVSI Online)that quantifies power system voltage stability in real time between an AC network and LCC HVDC using only local measurements.Previous methods relied on using telecommunications to inform a change in a predetermined AC network model.The proposed method uses local measurements of voltage and current from the HVDC using a newly developed,numerically robust technique called Moving Window Covariance to detect a change in the AC network in real time.These network parameters are fed to a newly devised index that accurately models and captures the dynamics of the interaction between an LCC HVDC and AC network.The index is used to quantify stability,but also to advise network operation.In an onset of instability due to network degradation,the proposed index can provide a power order value for the HVDC to restore stability.All as a self-contained module that can be implemented within a HVDC scheme.展开更多
To obtain a reasonable description of the hadron production at the LHC energies,the impact parameter dependent saturation model is modified by inclusion of an anomalous dimensionγ,which controls the slope of the scat...To obtain a reasonable description of the hadron production at the LHC energies,the impact parameter dependent saturation model is modified by inclusion of an anomalous dimensionγ,which controls the slope of the scattering amplitude in the transition from the dilute region to the saturation region.We calculate the transverse momentum distribution and nuclear modification factor of theπ^(0)and charged hadrons with the improved model,and the results are consistent with measurements performed at the LHC.Moreover,we use the original impact parameter dependent model to study the aforementioned measurements performed at the LHC by adjusting its parameters.We find that the improved model is more consistent with the experimental data than the original one,as the anomalous dimension plays a significant role in the suppression of the evolution of the scattering amplitude.展开更多
This paper aimed at describing numerical simulations of vortex-induced vibrations(VIVs) of a long flexible riser with different length-to-diameter ratio(aspect ratio) in uniform and shear currents. Three aspect ra...This paper aimed at describing numerical simulations of vortex-induced vibrations(VIVs) of a long flexible riser with different length-to-diameter ratio(aspect ratio) in uniform and shear currents. Three aspect ratios were simulated: L/D= 500, 750 and 1 000. The simulation was carried out by the in-house computational fluid dynamics(CFD) solver viv-FOAM-SJTU developed by the authors, which was coupled with the strip method and developed on the OpenFOAM platform. Moreover, the radial basis function(RBF) dynamic grid technique is applied to the viv-FOAM-SJTU solver to simulate the VIV in both in-line(IL) and cross-flow(CF) directions of flexible riser with high aspect ratio. The validation of the benchmark case has been completed. With the same parameters, the aspect ratio shows a significant influence on VIV of a long flexible riser. The increase of aspect ratio exerted a strong effect on the IL equilibrium position of the riser while producing little effect on the curvature of riser. With the aspect ratio rose from 500 to 1 000, the maximum IL mean displacement increased from 3 times the diameter to 8 times the diameter. On the other hand, the vibration mode of the riser would increase with the increase of aspect ratio. When the aspect ratio was 500, the CF vibration was shown as a standing wave with a 3-(rd) order single mode. When the aspect ratio was 1 000, the modal weights of the 5-(th) and 6-(th) modes are high, serving as the dominant modes. The effect of the flow profile on the oscillating mode becomes more and more apparent when the aspect ratio is high, and the dominant mode of riser in shear flow is usually higher than that in uniform flow. When the aspect ratio was 750, the CF oscillations in both uniform flow and shear flow showed multi-mode vibration of the 4-(th) and 5-(th) mode. While, the dominant mode in uniform flow is the 4-(th) order, and the dominant mode in shear flow is the 5-(th) order.展开更多
基金Project supported by the Natural Science Foundation of Heilongjiang Province of China (Grant No.LH2020A014)the Graduate Students' Research Innovation Project of Harbin Normal University (Grant No.HSDSSCX2022-47)。
文摘We conduct a theoretical analysis of the massive and tunable Goos–Hänchen(GH) shift on a polar crystal covered with periodical black phosphorus(BP)-patches in the THz range. The surface plasmon phonon polaritons(SPPPs), which are coupled by the surface phonon polaritons(SPh Ps) and surface plasmon polaritons(SPPs), can greatly increase GH shifts.Based on the in-plane anisotropy of BP, two typical metasurface models are designed and investigated. An enormous GH shift of about-7565.58 λ_(0) is achieved by adjusting the physical parameters of the BP-patches. In the designed metasurface structure, the maximum sensitivity accompanying large GH shifts can reach about 6.43 × 10^(8) λ_(0)/RIU, which is extremely sensitive to the size, carrier density, and layer number of BP. Compared with a traditional surface plasmon resonance sensor, the sensitivity is increased by at least two orders of magnitude. We believe that investigating metasurface-based SPPPs sensors could lead to high-sensitivity biochemical detection applications.
基金supported by the Research on the Prediction Mechanism of Corrosion for High Strength Steel in Deep Sea Service Driven by Multi-Scale,High-Dimension and Small-Sample Data(C2301002635)Research on the Influence of Nozzle Structure on the Scouring Effect of Submerged Water Jet(2023R411045)+1 种基金the Zhejiang Ocean University Outstanding Master’s Thesis Cultivation Project(ZJOUYJS20230018)the Scientific Research Project of Zhejiang Graduate Education Society in 2022(2022-021)which was gained by Chen.
文摘Water jet technology is widely used in submerged buried pipes as a non-traditional trenching process,often invol-ving a complex sediment response.An important adjustable and influential engineering variable in this technol-ogy is represented by the impinging distance.In this study,the FLOW-3D software was used to simulate the jet scouring of sand beds in a submerged environment.In particular,four sets of experimental conditions were con-sidered to discern the relationship between the maximum scour depth and mass and the impinging distance.As shown by the results,a critical impinging distance h0 exists by which the static scour depth can be maximized;the scour mass ratio between dynamic and static conditions decreases as the impinging distance increases.Moreover,the profile contours are similar when the erosion parameter Ec is in the range 0.35<Ec<2.Empirical equations applicable for predicting the jet trenching contour under both dynamic and static scour modes are also provided in this study.
基金supported by Research on the Influence of Nozzle Structure on the Scouring Effect of Submerged Water Jet(2023R411045)Design and Control Strategy Research of PEM Fuel Cell Hybrid Propulsion System for Ships(2024R411015)+1 种基金Zhejiang Ocean University Outstanding Master’s Thesis Cultivation Project(ZJOUYJS20230018)General Program of Education Department of Zhejiang Province(Y202250817)which was gained by Chen.
文摘Scouring experiments were conducted using a three-dimensional laser scanning technology for angles of the jet spanning the interval from 0°to 30°,and the characteristics of the scour hole in equilibrium conditions were investigated accordingly.The results indicate that the optimal scouring effects occur when the jet angle is in the ranges between 15°and 20°.Moreover,the dimensionless profiles of the scour hole exhibit a high degree of similarity at different jet angles.Numerical simulations conducted using the Flow-3D software to investigate the bed shear stress along the jet impingement surface have shown that this stress is influenced by both the resultant force and the jet impingement surface area.It reaches its maximum value when the jet is vertical,decreases rapidly as the jet starts to tilt,then increases slightly,and decreases again significantly when the angle exceeds 20°.
基金This work is supported by National Nature Fund of China(52071091)the Key Laboratory of Expressway Construction Machinery of Shanxi Province which is gained by Zhang(300102259512).
文摘Water jets are widely used in seabed scouring and desilting applications.In the present work,dedicated tests have been conducted using a jet scour model test platform and sand beds containing grains with different sizes.The FLOW-3D simulation software has also been used to tackle the problem form a numerical point of view.The boundary conditions of the simulation have been optimized to reduce the gap between the numerical results and the outcomes of the experimental tests.Scour area calculation has been based on a RNG k-εTurbulence model.Moreover,the FAVOR(Fractional Area Volume Obstacle Representation)technology has been selected for grid division to make the simulation results more accurate.Jet scours with inclination angles of 10–20°have been simulated.It has been found that jet scouring is greatly affected by the environmental water flow,that is,water flow can weaken the scouring capacity of the jets.
基金The paper was supported by National Nature Fund of China(52071091)the Key Laboratory of Expressway Construction Machinery of Shanxi Province which is gained by Zhang(300102259512).
文摘The effects of oblique submerged scouring jets on sand beds with various particle sizes have been studied experimentally.In particular,a total of 25 experiments have been carried out to explore the influences of the jet angle and application time on the considered submerged sand beds.Test results conducted with a specially-designed device have shown that the scouring efficiency attains a maximum when the inclination angle is in the range between 15°and 20°and then it decreases when the inclination angle becomes higher.
文摘Aimed at the hydrodynamic response for marine structures slamming into water, based on the mechanism analysis to the slamming process, and by combining 3D N-S equation and k-ε turbulent kinetic equation with structure fully 6DOF motion equation, a mathematical model for the wind-fluid-solid interaction is established in 3D marine structure slamming wave at free poses and wind-wave-flow complex environments. Compared with the results of physical model test, the numerical results from the slamming wave well correspond with the experimental results. Through the mathematical model, the wave-making issue of 3D marine structure at initial pose falls into water in different complex wind, wave and flow environments is investigated. The research results show that various kinds of natural factors and structure initial poses have different influence on the slamming wave, and there is an obvious rule in this process.
文摘The theory of integration to mathematical analysis is so important that many mathematicians continue to develop new theory to enlarge the class of integrable functions and simplify the Lebesgue theory integration. In this paper, by slight modifying the definition of the Henstock integral which was introduced by Jaroslav Kurzweil and Ralph Henstock, we present a new definition of integral on fractal sets. Furthermore, its integrability has been discussed, and the relationship between differentiation and integral is also established. As an example, the integral of Cantor function on Cantor set is calculated.
基金This work was supported by Key project of Hunan Provincial Education Department(20A191)Hunan teaching research and reform project(2019-134)+3 种基金Cooperative Education Fund of China Ministry of Education(201702113002,201801193119)Hunan Natural Science Foundation(2018JJ2138)Hunan teaching research and reform project(2019)Natural Science Foundation of Hunan Province(2020JJ7007).
文摘A game measurement model considering the attacker’s knowledge background is proposed based on the Bayesian game theory aiming at striking a balance between the protection of sensitive information and the quality of service.We quantified the sensitive level of information according to the user’s personalized sensitive information protection needs.Based on the probability distribution of sensitive level and attacker’s knowledge background type,the strategy combination of service provider and attacker was analyzed,and a game-based sensitive information protection model was constructed.Through the combination of strategies under Bayesian equilibrium,the information entropy was used to measure the leakage of sensitive information.Furthermore,in the paper the influence of the sensitive level of information and the attacker’s knowledge background on the strategy of both sides of the game was considered comprehensively.Further on,the leakage of the user’s sensitive information was measured.Finally,the feasibility of the model was described by experiments.
基金the 2019 Guangzhou Educational Science Planning Project(201912027)2018 Guangzhou Maritime College Innovation and Strong School Project(F410608)+2 种基金2020 Industry-University Cooperation Collaborative Education Project(Jiao Gao Si Han[2021]No.3202002325060,202002325052,202002325050)Teaching Quality and Teaching Reform Project of Logistics Engineering Key Major of Guangdong Provincial Undergraduate Colleges and Universities(Yue Gao Han[2020]19)Guangzhou Education Policy Research Project(ZCYJ20109)。
文摘The economic and social progress under the new era has put forward new requirements for logistics talents.Based on the teaching concept of OBE-CDIO as well as the training program and objectives of logistics management major in Guangzhou Maritime University,this study analyzes and discusses how the Logistics System Planning and Design course,which is targeted at students majoring in logistics management,enables the students to meet the graduation requirements by virtue of realizing the course objectives.
基金the Teaching Quality and Teaching Reform Project Logistics Engineering Key Major of Guangdong Provincial Undergraduate Colleges and Universities(Yue Gao Han[2020]19)2021 Teaching Construction Project of Guangzhou Maritime College(Guang Hang Yuan[2021]141)2020 Industry-University Cooperation Collaborative Education Project(Jiao Gao Si Han[2021]No.3202002325060,202002325052,202002325050).
文摘This study analyzes the background of ideological and political theories teaching in operations research courses and provides a design framework for ideological and political theories teaching in operations research courses based on“trinity”according to real teaching practices.This article summarizes the merging point of ideological and political theories teaching in operations research courses,taking ability and knowledge as its carrier and ideological and political theories teaching as its core,as well as discusses four methods of ideological and political theories teaching:online and offline interactive teaching,stimulating independent learning by practical application,seminar-style flipped classroom,and promoting theoretical teaching through competition and scientific research.
基金the Guangzhou Education Policy Research Project(ZCYJ20109)2020 Industry University Cooperation Collaborative Education Project(A Letter from the Division of Higher Education[2021]No.3,202002325060,202002325052,202002325050)2021 Teaching Construction Project of Guangzhou Maritime University,and 2019 Guangzhou Educational Science Planning Course(201912027).
文摘This article discusses the problems existing in the teaching of Logistics and the urgency of its curriculum reform,introduces the concept of outcome-based education(OBE)into the teaching process of Logistics,designs the teaching in a reverse direction guided by the results,and implements the teaching design in the form of flipped classroom.A“student-centered”teaching process endows students with stronger autonomy and initiative and encourages them to cooperate with each other.This teaching process provides new ideas and methods for the teaching reform of Logistics as well as the cultivation of excellent logistics talents.
文摘This paper proposes a low-rank spectral estimation algorithm of learning Markov model.First,an approximate projection algorithm for the rank-constrained frequency matrix set is proposed,and thereafter its local Lipschitzian error bound established.Then,we propose a low-rank spectral estimation algorithm for estimating the state transition frequency matrix and the probability matrix of Markov model by applying the approximate projection algorithm to correct the maximum likelihood estimation of the frequency matrix,and prove that there is only a multiplying constant difference in estimation errors between the low-rank spectral estimation and the maximum likelihood estimation under appropriate conditions.Finally,numerical comparisons with the prevailing maximum likelihood estimation,spectral estimation,and rank-constrained maxi-mum likelihood estimation show that the low-rank spectral estimation algorithm is effective.
基金Supported by the National Natural Science Foundation of China(12165004)the Basic and Applied Basic Research Project of Guangzhou Science and Technology Bureau(202201011324)+1 种基金the Education Department of Guizhou Province,China(QJJ[2022]016)the National Key Research and Development Program of China(2018YFE0104700,CCNU18ZDPY04)。
文摘We use the refined hot spot model to study the valence quark shape of the proton with the deeply virtual Compton scattering at high energies in the color glass condensate framework.To investigate the individual valence quark shape,a novel treatment of the valence quark width is employed.We calculate the cross-sections for coherent and incoherent deeply virtual Compton scattering using,for the first time,different widths(Bu and Bd)for the profile density distributions of the up and down quarks instead of using the same width as in the literature.We find that the cross-sections calculated with Bu≥Bd at each collision energy are consistent with each other,which is in agreement with theoretical expectations,whereas those computed with Bu<Bd show some discrepancies.This outcome implies that the up quark might emit more gluons than the down quark,leading to Bu≥Bd at high energy.The impact of energy on the outcome is estimated.Our results show that as the collision energy increases,the aforementioned discrepancies are not only significantly broadened,but also shift to a relatively smaller momentum transfer range at the future Electron-Ion Collider(EIC)and Large Hadron Electron Collider(LHeC)energies,which indicates that the EIC and LHeC can provide an unprecedented chance to access the shape of the valence quark of the proton.
基金supported by the Key Area Research and Development Program of Guangdong Province under Grant 2020B0101110003in part by Dongguan Science and Technology Special Commissioner Foundation under Grant 20231800500222.
文摘The space-air-ground integrated networks (SAGIN) has emerged as a critical paradigm to address the growing demands for global connectivity and enhanced communication services. This paper gives a thorough review of the strategies and methodologies for resource allocation within SAGIN, focusing on the challenges and solutions within its complex structure. With the advent of technologies such as 6G, the dynamics of resource optimization have become increasingly complex, necessitating innovative approaches for efficient management. We examine the application of mathematical optimization, game theory, artificial intelligence (AI), and dynamic optimization techniques in SAGIN,offering insights into their effectiveness in ensuring optimal resource distribution, minimizing delays, and maximizing network throughput and stability. The survey highlights the significant advances in AI-based methods,particularly deep learning and reinforcement learning, in tackling the inherent challenges of SAGIN resource allocation. Through a critical review of existing literature, this paper categorizes various resource allocation strategies, identifies current research gaps, and discusses potential future directions. Our findings highlight the crucial role of integrated and intelligent resource allocation mechanisms in realizing the full potential of SAGIN for next-generation communication networks.
文摘This paper proposes an online power system voltage stability index(PVSI Online)that quantifies power system voltage stability in real time between an AC network and LCC HVDC using only local measurements.Previous methods relied on using telecommunications to inform a change in a predetermined AC network model.The proposed method uses local measurements of voltage and current from the HVDC using a newly developed,numerically robust technique called Moving Window Covariance to detect a change in the AC network in real time.These network parameters are fed to a newly devised index that accurately models and captures the dynamics of the interaction between an LCC HVDC and AC network.The index is used to quantify stability,but also to advise network operation.In an onset of instability due to network degradation,the proposed index can provide a power order value for the HVDC to restore stability.All as a self-contained module that can be implemented within a HVDC scheme.
基金Supported by the National Natural Science Foundation of China(12165004,11765005,11947119)the Guizhou Provincial Science and Technology Projects(ZK[2023]027,[2019]5103)+1 种基金the Education Department of Guizhou Province,China(KY[2021]131)the National Key Research and Development Program of China(2018YFE0104700,CCNU18ZDPY04)。
文摘To obtain a reasonable description of the hadron production at the LHC energies,the impact parameter dependent saturation model is modified by inclusion of an anomalous dimensionγ,which controls the slope of the scattering amplitude in the transition from the dilute region to the saturation region.We calculate the transverse momentum distribution and nuclear modification factor of theπ^(0)and charged hadrons with the improved model,and the results are consistent with measurements performed at the LHC.Moreover,we use the original impact parameter dependent model to study the aforementioned measurements performed at the LHC by adjusting its parameters.We find that the improved model is more consistent with the experimental data than the original one,as the anomalous dimension plays a significant role in the suppression of the evolution of the scattering amplitude.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51490675,51379125,11432009 and 51579145)
文摘This paper aimed at describing numerical simulations of vortex-induced vibrations(VIVs) of a long flexible riser with different length-to-diameter ratio(aspect ratio) in uniform and shear currents. Three aspect ratios were simulated: L/D= 500, 750 and 1 000. The simulation was carried out by the in-house computational fluid dynamics(CFD) solver viv-FOAM-SJTU developed by the authors, which was coupled with the strip method and developed on the OpenFOAM platform. Moreover, the radial basis function(RBF) dynamic grid technique is applied to the viv-FOAM-SJTU solver to simulate the VIV in both in-line(IL) and cross-flow(CF) directions of flexible riser with high aspect ratio. The validation of the benchmark case has been completed. With the same parameters, the aspect ratio shows a significant influence on VIV of a long flexible riser. The increase of aspect ratio exerted a strong effect on the IL equilibrium position of the riser while producing little effect on the curvature of riser. With the aspect ratio rose from 500 to 1 000, the maximum IL mean displacement increased from 3 times the diameter to 8 times the diameter. On the other hand, the vibration mode of the riser would increase with the increase of aspect ratio. When the aspect ratio was 500, the CF vibration was shown as a standing wave with a 3-(rd) order single mode. When the aspect ratio was 1 000, the modal weights of the 5-(th) and 6-(th) modes are high, serving as the dominant modes. The effect of the flow profile on the oscillating mode becomes more and more apparent when the aspect ratio is high, and the dominant mode of riser in shear flow is usually higher than that in uniform flow. When the aspect ratio was 750, the CF oscillations in both uniform flow and shear flow showed multi-mode vibration of the 4-(th) and 5-(th) mode. While, the dominant mode in uniform flow is the 4-(th) order, and the dominant mode in shear flow is the 5-(th) order.