Information content security is a branch of cyberspace security. How to effectively manage and use Weibo comment information has become a research focus in the field of information content security. Three main tasks i...Information content security is a branch of cyberspace security. How to effectively manage and use Weibo comment information has become a research focus in the field of information content security. Three main tasks involved are emotion sentence identification and classification,emotion tendency classification,and emotion expression extraction. Combining with the latent Dirichlet allocation(LDA) model,a Gibbs sampling implementation for inference of our algorithm is presented,and can be used to categorize emotion tendency automatically with the computer. In accordance with the lower ratio of recall for emotion expression extraction in Weibo,use dependency parsing,divided into two categories with subject and object,summarized six kinds of dependency models from evaluating objects and emotion words,and proposed that a merge algorithm for evaluating objects can be accurately evaluated by participating in a public bakeoff and in the shared tasks among the best methods in the sub-task of emotion expression extraction,indicating the value of our method as not only innovative but practical.展开更多
Background Available data regarding clinical profile and management of elderly patients with atrial fibrillation （AF） according to dependency, fragility and cognitive impairment are scarce. The objective of the stud...Background Available data regarding clinical profile and management of elderly patients with atrial fibrillation （AF） according to dependency, fragility and cognitive impairment are scarce. The objective of the study was to analyze the biodemographic data, clinical profile and antithrombotic treatment according to dependency, fragility and cognitive impairment in elderly AF patients. Methods Cross- sectional and multi-center study performed in consecutive AF patients ≥ 75 years treated with oral anticoagulants ≥ 3 months attended in Internal Medicine Departments in Spain. Results A total of 837 patients （83.0 ± 5.0 years; CHA2DS2-VASc： 5.0 ± 1.4; HAS-BLED： 2.1 ± 0.9） were included. 44.4% of patients had some degree of dependency, 43.3% were fragile, and 32.3% had cognitive impairment. Patients with any of these conditions were older, had a worse clinical profile, with more comorbidities and higher risks of thromboembolic and bleeding events. All these conditions were independently associated among them. Overall, 70.8% of patients were taking vitamin K antagonists, the remaining 29.2% direct oral anticoagulants and 9.7% oral antiplatelets. This distribution was independent of the presence of dependency or fragility, but there was a trend to a higher prescription of vitamin K antagonists in those patients with cognitive impairment （75.2% vs. 68.8%; P = 0.05）. Conclusions Approximately 32%-44% of elderly anticoagulated AF patients attended have some degree of dependency, fragility and/or cognitive impairment. Patients with any of these conditions are older and have a worse clinical profile. Ap？proximately 71% of patients are taking vitamin K antagonists, regardless dependency or frailty, but with a trend to higher prescription in patients with cognitive impairment.展开更多
An enhanced small-signal model is introduced to model the influence of the impact ionization effect on the performance of In As/Al Sb HFET, in which an optimized fitting function D（ωτi） in the form of least square...An enhanced small-signal model is introduced to model the influence of the impact ionization effect on the performance of In As/Al Sb HFET, in which an optimized fitting function D（ωτi） in the form of least square approximation is proposed in order to further enhance the accuracy in modeling the frequency dependency of the impact ionization effect.The enhanced model with D（ωτi） can accurately characterize the key S parameters of In As/Al Sb HFET in a wide frequency range with a very low error function EF. It is demonstrated that the new fitting function D（ωτi） is helpful in further improving the modeling accuracy degree.展开更多
We propose a model of edge-coupled interdependent networks with directed dependency links(EINDDLs)and develop the theoretical analysis framework of this model based on the self-consistent probabilities method.The phas...We propose a model of edge-coupled interdependent networks with directed dependency links(EINDDLs)and develop the theoretical analysis framework of this model based on the self-consistent probabilities method.The phase transition behaviors and parameter thresholds of this model under random attacks are analyzed theoretically on both random regular(RR)networks and Erd¨os-Renyi(ER)networks,and computer simulations are performed to verify the results.In this EINDDL model,a fractionβof connectivity links within network B depends on network A and a fraction(1-β)of connectivity links within network A depends on network B.It is found that randomly removing a fraction(1-p)of connectivity links in network A at the initial state,network A exhibits different types of phase transitions(first order,second order and hybrid).Network B is rarely affected by cascading failure whenβis small,and network B will gradually converge from the first-order to the second-order phase transition asβincreases.We present the critical values ofβfor the phase change process of networks A and B,and give the critical values of p andβfor network B at the critical point of collapse.Furthermore,a cascading prevention strategy is proposed.The findings are of great significance for understanding the robustness of EINDDLs.展开更多
The cascading failure often occurs in real networks. It is significant to analyze the cascading failure in the complex network research. The dependency relation can change over time. Therefore, in this study, we inves...The cascading failure often occurs in real networks. It is significant to analyze the cascading failure in the complex network research. The dependency relation can change over time. Therefore, in this study, we investigate the cascading fail- ure in multilayer networks with dynamic dependency groups. We construct a model considering the recovery mechanism. In our model, two effects between layers are defined. Under Effect 1, the dependent nodes in other layers will be disabled as long as one node does not belong to the largest connected component in one layer. Under Effect 2, the dependent nodes in other layers will recover when one node belongs to the largest connected component. The theoretical solution of the largest component is deduced and the simulation results verify our theoretical solution. In the simulation, we analyze the influence factors of the network robustness, including the fraction of dependent nodes and the group size, in our model. It shows that increasing the fraction of dependent nodes and the group size will enhance the network robustness under Effect 1. On the contrary, these will reduce the network robustness under Effect 2. Meanwhile, we find that the tightness of the network connection will affect the robustness of networks. Furthermore, setting the average degree of network as 8 is enough to keep the network robust.展开更多
China’s foreign oil dependency level reached 64.4percent of total demand in 2016,3.8 percent higher than the previous year,and was expected to rise again in 2017,according to a leading economic think tank in China.Th...China’s foreign oil dependency level reached 64.4percent of total demand in 2016,3.8 percent higher than the previous year,and was expected to rise again in 2017,according to a leading economic think tank in China.The mainland’s domestic crude production dropped to 200million metric tons in 2016 due to high production costs of domestic crude oil at an average of US$45-50 per barrel,展开更多
The isospin splitting of the Dirac mass obtained using the relativistic Brueckner-Hartree-Fock(RBHF)theory was thor-oughly investigated.From the perspective in the full Dirac space,the long-standing controversy betwee...The isospin splitting of the Dirac mass obtained using the relativistic Brueckner-Hartree-Fock(RBHF)theory was thor-oughly investigated.From the perspective in the full Dirac space,the long-standing controversy between the momentum-independent approximation(MIA)method and the projection method on the isospin splitting of the Dirac mass in asymmetric nuclear matter was analyzed in detail.We found that the assumption procedure of the MIA method,which assumes that single-particle potentials are momentum independent,is not a sufficient condition that directly leads to the opposite sign of the isospin splitting of the Dirac mass,whereas the extraction procedure of the MIA method,which extracts single-particle potentials from single-particle potential energy,changes the sign.A formal expression of the Dirac mass was obtained by approximately solving a set of equations involved in the extraction procedure.The opposite isospin splitting of the Dirac mass was mainly caused by the extraction procedure,which forcibly assumed that the momentum dependence of the single-particle potential energy was in a quadratic form,in which the strength was solely determined by a constant scalar potential.Improved understanding of the isospin splitting of the Dirac mass from ab initio calculations could enhance our knowledge of neutron-rich systems,such as exotic nuclei and neutron stars.展开更多
Long-term urban traffic flow prediction is an important task in the field of intelligent transportation,as it can help optimize traffic management and improve travel efficiency.To improve prediction accuracy,a crucial...Long-term urban traffic flow prediction is an important task in the field of intelligent transportation,as it can help optimize traffic management and improve travel efficiency.To improve prediction accuracy,a crucial issue is how to model spatiotemporal dependency in urban traffic data.In recent years,many studies have adopted spatiotemporal neural networks to extract key information from traffic data.However,most models ignore the semantic spatial similarity between long-distance areas when mining spatial dependency.They also ignore the impact of predicted time steps on the next unpredicted time step for making long-term predictions.Moreover,these models lack a comprehensive data embedding process to represent complex spatiotemporal dependency.This paper proposes a multi-scale persistent spatiotemporal transformer(MSPSTT)model to perform accurate long-term traffic flow prediction in cities.MSPSTT adopts an encoder-decoder structure and incorporates temporal,periodic,and spatial features to fully embed urban traffic data to address these issues.The model consists of a spatiotemporal encoder and a spatiotemporal decoder,which rely on temporal,geospatial,and semantic space multi-head attention modules to dynamically extract temporal,geospatial,and semantic characteristics.The spatiotemporal decoder combines the context information provided by the encoder,integrates the predicted time step information,and is iteratively updated to learn the correlation between different time steps in the broader time range to improve the model’s accuracy for long-term prediction.Experiments on four public transportation datasets demonstrate that MSPSTT outperforms the existing models by up to 9.5%on three common metrics.展开更多
Based on the force-heat equivalence energy density principle,a theoretical model for magnetic metallic materials is developed,which characterizes the temperature-dependent magnetic anisotropy energy by considering the...Based on the force-heat equivalence energy density principle,a theoretical model for magnetic metallic materials is developed,which characterizes the temperature-dependent magnetic anisotropy energy by considering the equivalent relationship between magnetic anisotropy energy and heat energy;then the relationship between the magnetic anisotropy constant and saturation magnetization is considered.Finally,we formulate a temperature-dependent model for saturation magnetization,revealing the inherent relationship between temperature and saturation magnetization.Our model predicts the saturation magnetization for nine different magnetic metallic materials at different temperatures,exhibiting satisfactory agreement with experimental data.Additionally,the experimental data used as reference points are at or near room temperature.Compared to other phenomenological theoretical models,this model is considerably more accessible than the data required at 0 K.The index included in our model is set to a constant value,which is equal to 10/3 for materials other than Fe,Co,and Ni.For transition metals(Fe,Co,and Ni in this paper),the index is 6 in the range of 0 K to 0.65T_(cr)(T_(cr) is the critical temperature),and 3 in the range of 0.65T_(cr) to T_(cr),unlike other models where the adjustable parameters vary according to each material.In addition,our model provides a new way to design and evaluate magnetic metallic materials with superior magnetic properties over a wide range of temperatures.展开更多
It is challenging for aqueous Zn-ion batteries(ZIBs)to achieve comparable low-temperature(low-T)performance due to the easy-frozen electrolyte and severe Zn dendrites.Herein,an aqueous electrolyte with a low freezing ...It is challenging for aqueous Zn-ion batteries(ZIBs)to achieve comparable low-temperature(low-T)performance due to the easy-frozen electrolyte and severe Zn dendrites.Herein,an aqueous electrolyte with a low freezing point and high ionic conductivity is proposed.Combined with molecular dynamics simulation and multi-scale interface analysis(time of flight secondary ion mass spectrometry threedimensional mapping and in-situ electrochemical impedance spectroscopy method),the temperature independence of the V_(2)O_(5)cathode and Zn anode is observed to be opposite.Surprisingly,dominated by the solvent structure of the designed electrolyte at low temperatures,vanadium dissolution/shuttle is significantly inhibited,and the zinc dendrites caused by this electrochemical crosstalk are greatly relieved,thus showing an abnormal temperature inversion effect.Through the disclosure and improvement of the above phenomena,the designed Zn||V_(2)O_(5)full cell delivers superior low-T performance,maintaining almost 99%capacity retention after 9500 cycles(working more than 2500 h)at-20°C.This work proposes a kind of electrolyte suitable for low-T ZIBs and reveals the inverse temperature dependence of the Zn anode,which might offer a novel perspective for the investigation of low-T aqueous battery systems.展开更多
The recent discovery of field emission devices based on one-dimensional nanostructures has attracted much interest in emerging applications on next-generation flat panel displays,molecule-based sensors,and so forth.To...The recent discovery of field emission devices based on one-dimensional nanostructures has attracted much interest in emerging applications on next-generation flat panel displays,molecule-based sensors,and so forth.To achieve a comprehensive understanding of surface potentials at the nano-emitters during the tunneling process,in this study we systematically investigated the image potentials of single-walled boron nitride nanotubes with different edges,diameters and lengths in the frame of a composite first-principles calculation.The image potentials of zigzag single-walled boron nitride nanotubes are found to be dependent on the non-equivalent sides.Only the image potentials of isolated armchair single-walled boron nitride nanotube can be well fitted with the image potential of an ideal metal sphere of a size comparable to the tube diameter.On the contrary,the image potentials of zigzag and grounded armchair single-walled boron nitride nanotubes exhibit a strong length-dependence characteristic and are significantly different from that of an ideal metal sphere,which originates from the significant axial symmetry breaking of induced charge at the tip for the long tube.The correlation between the testing electron and electronic structure of single-walled boron nitride nanotube has also been discussed.展开更多
It is well known that femtosecond laser pulses can easily spontaneously induce deep-subwavelength periodic surface structures on transparent dielectrics but not on non-transparent semiconductors.Nevertheless,in this s...It is well known that femtosecond laser pulses can easily spontaneously induce deep-subwavelength periodic surface structures on transparent dielectrics but not on non-transparent semiconductors.Nevertheless,in this study,we demonstrate that using high-numerical-aperture 800 nm femtosecond laser direct writing with controlled pulse energy and scanning speed in the near-damage-threshold regime,polarization-dependent deep-subwavelength single grooves with linewidths of~180 nm can be controllably prepared on Si.Generally,the single-groove linewidth increases slightly with increase in the pulse energy and decrease in the scanning speed,whereas the single-groove depth significantly increases from~300 nm to~600 nm with decrease in the scanning speed,or even to over 1μm with multi-processing,indicating the characteristics of transverse clamping and longitudinal growth of such deep-subwavelength single grooves.Energy dispersive spectroscopy composition analysis of the near-groove region confirms that single-groove formation tends to be an ultrafast,non-thermal ablation process,and the oxidized deposits near the grooves are easy to clean up.Furthermore,the results,showing both the strong dependence of groove orientation on laser polarization and the occurrence of double-groove structures due to the interference of pre-formed orthogonal grooves,indicate that the extraordinary field enhancement of strong polarization sensitivity in the deep-subwavelength groove plays an important role in single-groove growth with high stability and collimation.展开更多
This paper is concerned with ultrahigh dimensional data analysis,which has become increasingly important in diverse scientific fields.We develop a sure independence screening procedure via the measure of conditional m...This paper is concerned with ultrahigh dimensional data analysis,which has become increasingly important in diverse scientific fields.We develop a sure independence screening procedure via the measure of conditional mean dependence based on Copula(CC-SIS,for short).The CC-SIS can be implemented as easily as the sure independence screening procedures which respectively based on the Pearson correlation,conditional mean and distance correlation(SIS,SIRS and DC-SIS,for short)and can significantly improve the performance of feature screening.We establish the sure screening property for the CC-SIS,and conduct simulations to examine its finite sample performance.Numerical comparison indicates that the CC-SIS performs better than the other two methods in various models.At last,we also illustrate the CC-SIS through a real data example.展开更多
Sentiment analysis of online reviews and other user generated content is an important research problem for its wide range of applications.In this paper,we propose a feature-based vector model and a novel weighting alg...Sentiment analysis of online reviews and other user generated content is an important research problem for its wide range of applications.In this paper,we propose a feature-based vector model and a novel weighting algorithm for sentiment analysis of Chinese product reviews.Specifically,an opinionated document is modeled by a set of feature-based vectors and corresponding weights.Different from previous work,our model considers modifying relationships between words and contains rich sentiment strength descriptions which are represented by adverbs of degree and punctuations.Dependency parsing is applied to construct the feature vectors.A novel feature weighting algorithm is proposed for supervised sentiment classification based on rich sentiment strength related information.The experimental results demonstrate the effectiveness of the proposed method compared with a state of the art method using term level weighting algorithms.展开更多
We conducted a study to find out if arbuscular mycorrhizal(AM) fungi(Acaulospora scrobiculata,Scutellospora calospora) and phosphate solubilizing bacteria(PSB, Paenibacillus polymyxa) inoculation either individually o...We conducted a study to find out if arbuscular mycorrhizal(AM) fungi(Acaulospora scrobiculata,Scutellospora calospora) and phosphate solubilizing bacteria(PSB, Paenibacillus polymyxa) inoculation either individually or in combinations can improve Acacia auriculiformis seedling growth, uptake of nutrients and quality in a phosphorus deficient tropical Alfisol. The seedlings were assessed for various growth and nutrient uptake parameters after 60 days of treatment. Inoculation with P.polymyxa stimulated mycorrhizal formation. Seedling height, stem girth, taproot length, number of leaves and leaf area, plant dry matter production, nodulation, and nodular dry weight were significantly higher for seedlings that were either dual inoculated or triple inoculated compared to individual inoculation of AM fungi or PSB, and uninoculated seedlings. Dual and triple application of AM fungi and PSB also significantly improved the nutrient contents of shoots and roots and nutrient uptake efficiencies. The calculated seedling quality indexes of the AM fungi and PSB inoculated seedling were 25–208% higher than uninoculated seedlings. These findings show that A.auriculiformis seedlings when dual inoculated or triple inoculated performed better than seedlings inoculated with the microbes individually and compared with uninoculated control seedlings. We conclude that bioinoculation is important for the production of high-quality A.auriculiformis seedlings in tree nurseries for planting in nutrient deficient soils.展开更多
A new method is proposed for constructing the Chinese sentential semantic structure in this paper. The method adopts the features including predicates, relations between predicates and basic arguments, relations betwe...A new method is proposed for constructing the Chinese sentential semantic structure in this paper. The method adopts the features including predicates, relations between predicates and basic arguments, relations between words, and case types to train the models of CRF ＋ ＋ and de- pendency parser. On the basis of the data set in Beijing Forest Studio-Chinese Tagged Corpus （ BFS- CTC）, the proposed method obtains precision value of 73.63% in open test. This result shows that the formalized computer processing can construct the sentential semantic structure absolutely. The features of predicates, topic and comment extracted with the method can be applied in Chinese in- formation processing directly for promoting the development of Chinese semantic analysis. The method makes the analysis of sentential semantic analysis based on large scale of data possible. It is a tool for expanding the corpus and has certain theoretical research and practical application value.展开更多
An electronegative collisional plasma having warm and massive positive ions,non-extensive distributed electrons and Boltzmann distributed negative ions is modelled for the plasma-surface interaction process that is us...An electronegative collisional plasma having warm and massive positive ions,non-extensive distributed electrons and Boltzmann distributed negative ions is modelled for the plasma-surface interaction process that is used for the surface nitriding.Specifically the sheath formation is evaluated through the Bohm’s criterion,which is found to be modified,and the variation of the sheath thickness and profiles of the density of plasma species and the net space charge density in the sheath region in addition to the electric potential.The effect of ion temperature,nonextensivity and collisional parameter is examined in greater detail considering the collisional cross-section to obey power-law dependency on the positive ion velocity.The positive ions are found to enter in the sheath region at lower velocities in the collisional plasma compared to the case of collision-less plasma;this velocity sees minuscule reduction with increasing nonextensivity.The increasing ion temperature and collisional parameter lead to the formation of sheath with smaller thickness.展开更多
In this paper, based on rough set theory and relational database, the relationship between rough relational database (RRDB) and fuzzy relational database (FRDB) is analyzed systematically from functional dependency, n...In this paper, based on rough set theory and relational database, the relationship between rough relational database (RRDB) and fuzzy relational database (FRDB) is analyzed systematically from functional dependency, normal form and Armstrong axiom. The results show that both fuzzy functional dependency and rough functional dependency are the generalizations of classical functional dependency.Fuzzy normal form is the expansion of classical normal form while rough normal form is an independent system.RRDB and FRDB obey Armstrong axiom to some extent from the point of view of inference rule.展开更多
With the growing popularity of data-intensive services on the Internet, the traditional process-centric model for business process meets challenges due to the lack of abilities to describe data semantics and dependenc...With the growing popularity of data-intensive services on the Internet, the traditional process-centric model for business process meets challenges due to the lack of abilities to describe data semantics and dependencies, resulting in the inflexibility of the design and implement for the processes. This paper proposes a novel data-aware business process model which is able to describe both explicit control flow and implicit data flow. Data model with dependencies which are formulated by Linear-time Temporal Logic(LTL) is presented, and their satisfiability is validated by an automaton-based model checking algorithm. Data dependencies are fully considered in modeling phase, which helps to improve the efficiency and reliability of programming during developing phase. Finally, a prototype system based on j BPM for data-aware workflow is designed using such model, and has been deployed to Beijing Kingfore heating management system to validate the flexibility, efficacy and convenience of our approach for massive coding and large-scale system management in reality.展开更多
基金supported by National Key Basic Research Program of China (No.2014CB340600)partially supported by National Natural Science Foundation of China (Grant Nos.61332019,61672531)partially supported by National Social Science Foundation of China (Grant No.14GJ003-152)
文摘Information content security is a branch of cyberspace security. How to effectively manage and use Weibo comment information has become a research focus in the field of information content security. Three main tasks involved are emotion sentence identification and classification,emotion tendency classification,and emotion expression extraction. Combining with the latent Dirichlet allocation(LDA) model,a Gibbs sampling implementation for inference of our algorithm is presented,and can be used to categorize emotion tendency automatically with the computer. In accordance with the lower ratio of recall for emotion expression extraction in Weibo,use dependency parsing,divided into two categories with subject and object,summarized six kinds of dependency models from evaluating objects and emotion words,and proposed that a merge algorithm for evaluating objects can be accurately evaluated by participating in a public bakeoff and in the shared tasks among the best methods in the sub-task of emotion expression extraction,indicating the value of our method as not only innovative but practical.
文摘Background Available data regarding clinical profile and management of elderly patients with atrial fibrillation （AF） according to dependency, fragility and cognitive impairment are scarce. The objective of the study was to analyze the biodemographic data, clinical profile and antithrombotic treatment according to dependency, fragility and cognitive impairment in elderly AF patients. Methods Cross- sectional and multi-center study performed in consecutive AF patients ≥ 75 years treated with oral anticoagulants ≥ 3 months attended in Internal Medicine Departments in Spain. Results A total of 837 patients （83.0 ± 5.0 years; CHA2DS2-VASc： 5.0 ± 1.4; HAS-BLED： 2.1 ± 0.9） were included. 44.4% of patients had some degree of dependency, 43.3% were fragile, and 32.3% had cognitive impairment. Patients with any of these conditions were older, had a worse clinical profile, with more comorbidities and higher risks of thromboembolic and bleeding events. All these conditions were independently associated among them. Overall, 70.8% of patients were taking vitamin K antagonists, the remaining 29.2% direct oral anticoagulants and 9.7% oral antiplatelets. This distribution was independent of the presence of dependency or fragility, but there was a trend to a higher prescription of vitamin K antagonists in those patients with cognitive impairment （75.2% vs. 68.8%; P = 0.05）. Conclusions Approximately 32%-44% of elderly anticoagulated AF patients attended have some degree of dependency, fragility and/or cognitive impairment. Patients with any of these conditions are older and have a worse clinical profile. Ap？proximately 71% of patients are taking vitamin K antagonists, regardless dependency or frailty, but with a trend to higher prescription in patients with cognitive impairment.
文摘An enhanced small-signal model is introduced to model the influence of the impact ionization effect on the performance of In As/Al Sb HFET, in which an optimized fitting function D（ωτi） in the form of least square approximation is proposed in order to further enhance the accuracy in modeling the frequency dependency of the impact ionization effect.The enhanced model with D（ωτi） can accurately characterize the key S parameters of In As/Al Sb HFET in a wide frequency range with a very low error function EF. It is demonstrated that the new fitting function D（ωτi） is helpful in further improving the modeling accuracy degree.
基金the National Natural Science Foundation of China(Grant Nos.61973118,51741902,11761033,12075088,and 11835003)Project in JiangXi Province Department of Science and Technology(Grant Nos.20212BBE51010 and 20182BCB22009)the Natural Science Foundation of Zhejiang Province(Grant No.Y22F035316)。
文摘We propose a model of edge-coupled interdependent networks with directed dependency links(EINDDLs)and develop the theoretical analysis framework of this model based on the self-consistent probabilities method.The phase transition behaviors and parameter thresholds of this model under random attacks are analyzed theoretically on both random regular(RR)networks and Erd¨os-Renyi(ER)networks,and computer simulations are performed to verify the results.In this EINDDL model,a fractionβof connectivity links within network B depends on network A and a fraction(1-β)of connectivity links within network A depends on network B.It is found that randomly removing a fraction(1-p)of connectivity links in network A at the initial state,network A exhibits different types of phase transitions(first order,second order and hybrid).Network B is rarely affected by cascading failure whenβis small,and network B will gradually converge from the first-order to the second-order phase transition asβincreases.We present the critical values ofβfor the phase change process of networks A and B,and give the critical values of p andβfor network B at the critical point of collapse.Furthermore,a cascading prevention strategy is proposed.The findings are of great significance for understanding the robustness of EINDDLs.
基金Project supported by the National Natural Science Foundation of China(Grant No.61601053)
文摘The cascading failure often occurs in real networks. It is significant to analyze the cascading failure in the complex network research. The dependency relation can change over time. Therefore, in this study, we investigate the cascading fail- ure in multilayer networks with dynamic dependency groups. We construct a model considering the recovery mechanism. In our model, two effects between layers are defined. Under Effect 1, the dependent nodes in other layers will be disabled as long as one node does not belong to the largest connected component in one layer. Under Effect 2, the dependent nodes in other layers will recover when one node belongs to the largest connected component. The theoretical solution of the largest component is deduced and the simulation results verify our theoretical solution. In the simulation, we analyze the influence factors of the network robustness, including the fraction of dependent nodes and the group size, in our model. It shows that increasing the fraction of dependent nodes and the group size will enhance the network robustness under Effect 1. On the contrary, these will reduce the network robustness under Effect 2. Meanwhile, we find that the tightness of the network connection will affect the robustness of networks. Furthermore, setting the average degree of network as 8 is enough to keep the network robust.
文摘China’s foreign oil dependency level reached 64.4percent of total demand in 2016,3.8 percent higher than the previous year,and was expected to rise again in 2017,according to a leading economic think tank in China.The mainland’s domestic crude production dropped to 200million metric tons in 2016 due to high production costs of domestic crude oil at an average of US$45-50 per barrel,
基金supported in part by the China Postdoctoral Science Foundation under grant No.2021M700610the National Natural Science Foundation of China(NSFC)(No.12205030)+1 种基金the Fundamental Research Funds for the Central Universities(No.2024CDJXY022)the Institute for Basic Science(No.IBS-R031-D1).
文摘The isospin splitting of the Dirac mass obtained using the relativistic Brueckner-Hartree-Fock(RBHF)theory was thor-oughly investigated.From the perspective in the full Dirac space,the long-standing controversy between the momentum-independent approximation(MIA)method and the projection method on the isospin splitting of the Dirac mass in asymmetric nuclear matter was analyzed in detail.We found that the assumption procedure of the MIA method,which assumes that single-particle potentials are momentum independent,is not a sufficient condition that directly leads to the opposite sign of the isospin splitting of the Dirac mass,whereas the extraction procedure of the MIA method,which extracts single-particle potentials from single-particle potential energy,changes the sign.A formal expression of the Dirac mass was obtained by approximately solving a set of equations involved in the extraction procedure.The opposite isospin splitting of the Dirac mass was mainly caused by the extraction procedure,which forcibly assumed that the momentum dependence of the single-particle potential energy was in a quadratic form,in which the strength was solely determined by a constant scalar potential.Improved understanding of the isospin splitting of the Dirac mass from ab initio calculations could enhance our knowledge of neutron-rich systems,such as exotic nuclei and neutron stars.
基金the National Natural Science Foundation of China under Grant No.62272087Science and Technology Planning Project of Sichuan Province under Grant No.2023YFG0161.
文摘Long-term urban traffic flow prediction is an important task in the field of intelligent transportation,as it can help optimize traffic management and improve travel efficiency.To improve prediction accuracy,a crucial issue is how to model spatiotemporal dependency in urban traffic data.In recent years,many studies have adopted spatiotemporal neural networks to extract key information from traffic data.However,most models ignore the semantic spatial similarity between long-distance areas when mining spatial dependency.They also ignore the impact of predicted time steps on the next unpredicted time step for making long-term predictions.Moreover,these models lack a comprehensive data embedding process to represent complex spatiotemporal dependency.This paper proposes a multi-scale persistent spatiotemporal transformer(MSPSTT)model to perform accurate long-term traffic flow prediction in cities.MSPSTT adopts an encoder-decoder structure and incorporates temporal,periodic,and spatial features to fully embed urban traffic data to address these issues.The model consists of a spatiotemporal encoder and a spatiotemporal decoder,which rely on temporal,geospatial,and semantic space multi-head attention modules to dynamically extract temporal,geospatial,and semantic characteristics.The spatiotemporal decoder combines the context information provided by the encoder,integrates the predicted time step information,and is iteratively updated to learn the correlation between different time steps in the broader time range to improve the model’s accuracy for long-term prediction.Experiments on four public transportation datasets demonstrate that MSPSTT outperforms the existing models by up to 9.5%on three common metrics.
基金Project supported by the Natural Science Foundation of Chongqing(Grant No.CSTB2022NSCQ-MSX0391)。
文摘Based on the force-heat equivalence energy density principle,a theoretical model for magnetic metallic materials is developed,which characterizes the temperature-dependent magnetic anisotropy energy by considering the equivalent relationship between magnetic anisotropy energy and heat energy;then the relationship between the magnetic anisotropy constant and saturation magnetization is considered.Finally,we formulate a temperature-dependent model for saturation magnetization,revealing the inherent relationship between temperature and saturation magnetization.Our model predicts the saturation magnetization for nine different magnetic metallic materials at different temperatures,exhibiting satisfactory agreement with experimental data.Additionally,the experimental data used as reference points are at or near room temperature.Compared to other phenomenological theoretical models,this model is considerably more accessible than the data required at 0 K.The index included in our model is set to a constant value,which is equal to 10/3 for materials other than Fe,Co,and Ni.For transition metals(Fe,Co,and Ni in this paper),the index is 6 in the range of 0 K to 0.65T_(cr)(T_(cr) is the critical temperature),and 3 in the range of 0.65T_(cr) to T_(cr),unlike other models where the adjustable parameters vary according to each material.In addition,our model provides a new way to design and evaluate magnetic metallic materials with superior magnetic properties over a wide range of temperatures.
基金financially supported by the National Natural Science Foundation of China(52372191)the Natural Science Foundation of Xiamen,China(3502Z202372036)+1 种基金the China Postdoctoral Science Foundation(2022TQ0282)the support of the High-Performance Computing Center(HPCC)at Harbin Institute of Technology on first-principles calculations。
文摘It is challenging for aqueous Zn-ion batteries(ZIBs)to achieve comparable low-temperature(low-T)performance due to the easy-frozen electrolyte and severe Zn dendrites.Herein,an aqueous electrolyte with a low freezing point and high ionic conductivity is proposed.Combined with molecular dynamics simulation and multi-scale interface analysis(time of flight secondary ion mass spectrometry threedimensional mapping and in-situ electrochemical impedance spectroscopy method),the temperature independence of the V_(2)O_(5)cathode and Zn anode is observed to be opposite.Surprisingly,dominated by the solvent structure of the designed electrolyte at low temperatures,vanadium dissolution/shuttle is significantly inhibited,and the zinc dendrites caused by this electrochemical crosstalk are greatly relieved,thus showing an abnormal temperature inversion effect.Through the disclosure and improvement of the above phenomena,the designed Zn||V_(2)O_(5)full cell delivers superior low-T performance,maintaining almost 99%capacity retention after 9500 cycles(working more than 2500 h)at-20°C.This work proposes a kind of electrolyte suitable for low-T ZIBs and reveals the inverse temperature dependence of the Zn anode,which might offer a novel perspective for the investigation of low-T aqueous battery systems.
基金the financial support from the National Natural Science Foundation of China(Grant Nos.12004083 and 51972069)the Science and Technology Projects in Guangzhou(Grant Nos.202102020350 and 202102010470)+7 种基金the National Key R&D Program of China(Grant No.2016YFB0200800)the Opening Project of Joint Laboratory for Planetary Science and Supercomputing(Grant No.CSYYGS-QT-2024-14)the Key-Area Research and Development Program of Guangdong Province(Grant No.2019B030330001)the College Students Innovation and Entrepreneurship Training Program of Guangdong Province(Grant No.S202311078133)Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(Grant No.202255464)the National Supercomputer Center in Guangzhouthe National Supercomputing Center in Chengduthe Network Center of Guangzhou University。
文摘The recent discovery of field emission devices based on one-dimensional nanostructures has attracted much interest in emerging applications on next-generation flat panel displays,molecule-based sensors,and so forth.To achieve a comprehensive understanding of surface potentials at the nano-emitters during the tunneling process,in this study we systematically investigated the image potentials of single-walled boron nitride nanotubes with different edges,diameters and lengths in the frame of a composite first-principles calculation.The image potentials of zigzag single-walled boron nitride nanotubes are found to be dependent on the non-equivalent sides.Only the image potentials of isolated armchair single-walled boron nitride nanotube can be well fitted with the image potential of an ideal metal sphere of a size comparable to the tube diameter.On the contrary,the image potentials of zigzag and grounded armchair single-walled boron nitride nanotubes exhibit a strong length-dependence characteristic and are significantly different from that of an ideal metal sphere,which originates from the significant axial symmetry breaking of induced charge at the tip for the long tube.The correlation between the testing electron and electronic structure of single-walled boron nitride nanotube has also been discussed.
基金Project supported by the Natural Science Foundation of Guangdong Province (Grant No.2021A1515012335)the National Natural Science Foundation of China (Grant No.11274400)+2 种基金Pearl River S&T Nova Program of Guangzhou (Grant No.201506010059)State Key Laboratory of High Field Laser Physics (Shanghai Institute of Optics and Fine Mechanics)State Key Laboratory of Optoelectronic Materials and Technologies (Sun Yat-Sen University)。
文摘It is well known that femtosecond laser pulses can easily spontaneously induce deep-subwavelength periodic surface structures on transparent dielectrics but not on non-transparent semiconductors.Nevertheless,in this study,we demonstrate that using high-numerical-aperture 800 nm femtosecond laser direct writing with controlled pulse energy and scanning speed in the near-damage-threshold regime,polarization-dependent deep-subwavelength single grooves with linewidths of~180 nm can be controllably prepared on Si.Generally,the single-groove linewidth increases slightly with increase in the pulse energy and decrease in the scanning speed,whereas the single-groove depth significantly increases from~300 nm to~600 nm with decrease in the scanning speed,or even to over 1μm with multi-processing,indicating the characteristics of transverse clamping and longitudinal growth of such deep-subwavelength single grooves.Energy dispersive spectroscopy composition analysis of the near-groove region confirms that single-groove formation tends to be an ultrafast,non-thermal ablation process,and the oxidized deposits near the grooves are easy to clean up.Furthermore,the results,showing both the strong dependence of groove orientation on laser polarization and the occurrence of double-groove structures due to the interference of pre-formed orthogonal grooves,indicate that the extraordinary field enhancement of strong polarization sensitivity in the deep-subwavelength groove plays an important role in single-groove growth with high stability and collimation.
基金Supported by Natural Science Foundation of Henan(Grant No.202300410066)Program for Science and Technology Development of Henan Province(Grant No.242102310350).
文摘This paper is concerned with ultrahigh dimensional data analysis,which has become increasingly important in diverse scientific fields.We develop a sure independence screening procedure via the measure of conditional mean dependence based on Copula(CC-SIS,for short).The CC-SIS can be implemented as easily as the sure independence screening procedures which respectively based on the Pearson correlation,conditional mean and distance correlation(SIS,SIRS and DC-SIS,for short)and can significantly improve the performance of feature screening.We establish the sure screening property for the CC-SIS,and conduct simulations to examine its finite sample performance.Numerical comparison indicates that the CC-SIS performs better than the other two methods in various models.At last,we also illustrate the CC-SIS through a real data example.
基金This work was supported in part by National Natural Science Foundation of China under Grants No.60970052，the Beijing Natural Science Foundation under Grants No.4133084，the Beijing Educational Committee Science and Technology Development Planned under Grants No.KM201410028017 and the Beijing Key Disciplines of Computer Application Technology
文摘Sentiment analysis of online reviews and other user generated content is an important research problem for its wide range of applications.In this paper,we propose a feature-based vector model and a novel weighting algorithm for sentiment analysis of Chinese product reviews.Specifically,an opinionated document is modeled by a set of feature-based vectors and corresponding weights.Different from previous work,our model considers modifying relationships between words and contains rich sentiment strength descriptions which are represented by adverbs of degree and punctuations.Dependency parsing is applied to construct the feature vectors.A novel feature weighting algorithm is proposed for supervised sentiment classification based on rich sentiment strength related information.The experimental results demonstrate the effectiveness of the proposed method compared with a state of the art method using term level weighting algorithms.
文摘We conducted a study to find out if arbuscular mycorrhizal(AM) fungi(Acaulospora scrobiculata,Scutellospora calospora) and phosphate solubilizing bacteria(PSB, Paenibacillus polymyxa) inoculation either individually or in combinations can improve Acacia auriculiformis seedling growth, uptake of nutrients and quality in a phosphorus deficient tropical Alfisol. The seedlings were assessed for various growth and nutrient uptake parameters after 60 days of treatment. Inoculation with P.polymyxa stimulated mycorrhizal formation. Seedling height, stem girth, taproot length, number of leaves and leaf area, plant dry matter production, nodulation, and nodular dry weight were significantly higher for seedlings that were either dual inoculated or triple inoculated compared to individual inoculation of AM fungi or PSB, and uninoculated seedlings. Dual and triple application of AM fungi and PSB also significantly improved the nutrient contents of shoots and roots and nutrient uptake efficiencies. The calculated seedling quality indexes of the AM fungi and PSB inoculated seedling were 25–208% higher than uninoculated seedlings. These findings show that A.auriculiformis seedlings when dual inoculated or triple inoculated performed better than seedlings inoculated with the microbes individually and compared with uninoculated control seedlings. We conclude that bioinoculation is important for the production of high-quality A.auriculiformis seedlings in tree nurseries for planting in nutrient deficient soils.
基金Supported by the Science and Technology Innovation Plan of Beijing Institute of Technology(2013)
文摘A new method is proposed for constructing the Chinese sentential semantic structure in this paper. The method adopts the features including predicates, relations between predicates and basic arguments, relations between words, and case types to train the models of CRF ＋ ＋ and de- pendency parser. On the basis of the data set in Beijing Forest Studio-Chinese Tagged Corpus （ BFS- CTC）, the proposed method obtains precision value of 73.63% in open test. This result shows that the formalized computer processing can construct the sentential semantic structure absolutely. The features of predicates, topic and comment extracted with the method can be applied in Chinese in- formation processing directly for promoting the development of Chinese semantic analysis. The method makes the analysis of sentential semantic analysis based on large scale of data possible. It is a tool for expanding the corpus and has certain theoretical research and practical application value.
基金Rajat Dhawan acknowledges the Council of Scientific and Industrial Research(CSIR),Government of India for providing financial support(Grant Reference Number:09/086(1289)/2017-EMR-1).
文摘An electronegative collisional plasma having warm and massive positive ions,non-extensive distributed electrons and Boltzmann distributed negative ions is modelled for the plasma-surface interaction process that is used for the surface nitriding.Specifically the sheath formation is evaluated through the Bohm’s criterion,which is found to be modified,and the variation of the sheath thickness and profiles of the density of plasma species and the net space charge density in the sheath region in addition to the electric potential.The effect of ion temperature,nonextensivity and collisional parameter is examined in greater detail considering the collisional cross-section to obey power-law dependency on the positive ion velocity.The positive ions are found to enter in the sheath region at lower velocities in the collisional plasma compared to the case of collision-less plasma;this velocity sees minuscule reduction with increasing nonextensivity.The increasing ion temperature and collisional parameter lead to the formation of sheath with smaller thickness.
文摘In this paper, based on rough set theory and relational database, the relationship between rough relational database (RRDB) and fuzzy relational database (FRDB) is analyzed systematically from functional dependency, normal form and Armstrong axiom. The results show that both fuzzy functional dependency and rough functional dependency are the generalizations of classical functional dependency.Fuzzy normal form is the expansion of classical normal form while rough normal form is an independent system.RRDB and FRDB obey Armstrong axiom to some extent from the point of view of inference rule.
基金supported by the National Natural Science Foundation of China (No. 61502043, No. 61132001)Beijing Natural Science Foundation (No. 4162042)BeiJing Talents Fund (No. 2015000020124G082)
文摘With the growing popularity of data-intensive services on the Internet, the traditional process-centric model for business process meets challenges due to the lack of abilities to describe data semantics and dependencies, resulting in the inflexibility of the design and implement for the processes. This paper proposes a novel data-aware business process model which is able to describe both explicit control flow and implicit data flow. Data model with dependencies which are formulated by Linear-time Temporal Logic(LTL) is presented, and their satisfiability is validated by an automaton-based model checking algorithm. Data dependencies are fully considered in modeling phase, which helps to improve the efficiency and reliability of programming during developing phase. Finally, a prototype system based on j BPM for data-aware workflow is designed using such model, and has been deployed to Beijing Kingfore heating management system to validate the flexibility, efficacy and convenience of our approach for massive coding and large-scale system management in reality.
