This paper focused on investigating local tensile strength of connection between steel beam flange and concrete-filled circular column tube with through diaphragm. Three specimens were designed and tested to failure, ...This paper focused on investigating local tensile strength of connection between steel beam flange and concrete-filled circular column tube with through diaphragm. Three specimens were designed and tested to failure, and the structure behavior was studied by experiment and FEM analysis. On the basis of the results obtained, an estimation for local plastic and ultimate strengths of the connections using yield line theory was attempted, which results in a good prediction.展开更多
Synchronization of N different coupled chaotic systems with ring and chain connections is investigated. The New system, the Chen system, the Lii system, the Lorenz system, and the Rossler system are used as examples i...Synchronization of N different coupled chaotic systems with ring and chain connections is investigated. The New system, the Chen system, the Lii system, the Lorenz system, and the Rossler system are used as examples in verifying effectiveness of the method. Based on the Lyapunov stability theory, the form of the controller is designed and the area of the coupling coefficients is determined. Simulations indicate that global synchronization of the N different chaotic systems can be realized by choosing appropriate coupling coefficients by using the controller.展开更多
Material exchange frequently occurs in gullies,and thus the relationship between a gullynetwork structure and sediment transport potential has attracted considerable interest.However,previous researches ignored the di...Material exchange frequently occurs in gullies,and thus the relationship between a gullynetwork structure and sediment transport potential has attracted considerable interest.However,previous researches ignored the difficulty of material transport from sources to sinks,and did not quantify the connectivity of a network structure.In this study,we used a graph model structure to model gully networks of six typical sample areas in the Loess Plateau of China and quantified gully network connectivity using four indexes:average node strength,accessibility from sources to sinks,potential flow,and network structural connectivity index.Results show that:(1)Reflected by different quantitative indexes,the trends of gully network connectivity in different regions are similar.From north to south,the connectivity of a sample area first increases and then decreases.(2)The more mature gullies have stronger network connectivity.Small resistance is conducive to material transport in the gullies.(3)The node connectivity index of the gully network shows a significant aggregation distribution in space,and node connectivity on the main channel is often stronger than that on the branch trench.These results not only deepen the understanding of the process and mechanism of loess gully geomorphic development and evolution but also provide a reference for geomorphic studies.展开更多
I show how many connections of Γ?are presently existing from R?to β?as they are being inputted simultaneously through tensor products. I plan to address the Quantum state of this tensor connection st...I show how many connections of Γ?are presently existing from R?to β?as they are being inputted simultaneously through tensor products. I plan to address the Quantum state of this tensor connection step by step throughout the application presented. Also, I will show you how to prove that the connection is true for this tensor connection through its output method using a small bit of tensor calculus and mostly number theory.展开更多
Discourse connectives can be dealt with in relevance-theoretic terms, as indicators of types of relevance. These connectives can be used to constrain the interpretation of an utterance. They are analyzed in a broad cl...Discourse connectives can be dealt with in relevance-theoretic terms, as indicators of types of relevance. These connectives can be used to constrain the interpretation of an utterance. They are analyzed in a broad classification outlined in discourse connectives which introduce contextual implications, which are concerned with strengthening and which introduce denials. A relevance based approach to discourse is a more adequate framework than a coherence based one for the analysis of discourse connectives.展开更多
In this paper, we conduct research on the applications of advanced mathematics on the mathematical modeling and the inner connections with linear algebra and the probability statistics. Aiming at model in mathematical...In this paper, we conduct research on the applications of advanced mathematics on the mathematical modeling and the inner connections with linear algebra and the probability statistics. Aiming at model in mathematical modeling and solving and model of evaluation and promotion of the two links, put forward the "bystander" and "the authorities" this two characters, and points out that excellent mathematical modeling participants should have "from a bystander to the authorities" and "from the authorities to return to bystanders" two-way role transformation ability. Great situation in mathematics teaching, by means of the mathematical modeling formed in the development of the teachers, as well as the teaching thought, teaching experience and achievements, the onward march of mathematical experiment should be faster than mathematical modeling. Our research provides the new paradigm for the math development which will be meaningful.展开更多
Patients with mild traumatic brain injury have a diverse clinical presentation,and the underlying pathophysiology remains poorly understood.Magnetic resonance imaging is a non-invasive technique that has been widely u...Patients with mild traumatic brain injury have a diverse clinical presentation,and the underlying pathophysiology remains poorly understood.Magnetic resonance imaging is a non-invasive technique that has been widely utilized to investigate neuro biological markers after mild traumatic brain injury.This approach has emerged as a promising tool for investigating the pathogenesis of mild traumatic brain injury.G raph theory is a quantitative method of analyzing complex networks that has been widely used to study changes in brain structure and function.However,most previous mild traumatic brain injury studies using graph theory have focused on specific populations,with limited exploration of simultaneous abnormalities in structural and functional connectivity.Given that mild traumatic brain injury is the most common type of traumatic brain injury encounte red in clinical practice,further investigation of the patient characteristics and evolution of structural and functional connectivity is critical.In the present study,we explored whether abnormal structural and functional connectivity in the acute phase could serve as indicators of longitudinal changes in imaging data and cognitive function in patients with mild traumatic brain injury.In this longitudinal study,we enrolled 46 patients with mild traumatic brain injury who were assessed within 2 wee ks of injury,as well as 36 healthy controls.Resting-state functional magnetic resonance imaging and diffusion-weighted imaging data were acquired for graph theoretical network analysis.In the acute phase,patients with mild traumatic brain injury demonstrated reduced structural connectivity in the dorsal attention network.More than 3 months of followup data revealed signs of recovery in structural and functional connectivity,as well as cognitive function,in 22 out of the 46 patients.Furthermore,better cognitive function was associated with more efficient networks.Finally,our data indicated that small-worldness in the acute stage could serve as a predictor of longitudinal changes in connectivity in patients with mild traumatic brain injury.These findings highlight the importance of integrating structural and functional connectivity in unde rstanding the occurrence and evolution of mild traumatic brain injury.Additionally,exploratory analysis based on subnetworks could serve a predictive function in the prognosis of patients with mild traumatic brain injury.展开更多
The integration of ideological and political curriculum which exists in colleges and compulsory education is a powerful guarantee for enhancing the effectiveness of the course.Putting theoretical content as well as te...The integration of ideological and political curriculum which exists in colleges and compulsory education is a powerful guarantee for enhancing the effectiveness of the course.Putting theoretical content as well as teaching practice into effect contributes to every improvement and new idea about the curriculum.Facing the new circumstances,new tasks,and new challenges under the social background,it is necessary to reinforce the connection of the integration of the subject in universities and colleges and compulsory education,and take problems as the research direction for the sake of expanding the channels for courses ideological and political construction,and understand the integrated evolution of ideological and political theory courses of undergraduate and specialist education and compulsory education to a higher degree.Grasping the current situation and problems of the theory curriculum in colleges and compulsory education,and exploring the content of the theory in undergraduate and specialist education and compulsory education are of great significance,both in the integrated construction of ideological and political theory courses of undergraduate and specialist education and compulsory education and in making the best of the courses to implement the basic task of fostering people.展开更多
A new procedure is proposed to ease the analyses of the free vibration of an elastically connected identical plates system with respect to Kirchhoff plate theory.A structure of n parallel,elastically connected rectang...A new procedure is proposed to ease the analyses of the free vibration of an elastically connected identical plates system with respect to Kirchhoff plate theory.A structure of n parallel,elastically connected rectangular plates is of concern,whereby the motion is explained by a set of n coupled partial differential equations.The method involves a new change in variables to uncouple equations and form an equal system of n decoupled plates,while each is assumed to be elastically connected to the ground.The differential quadrature method is adopted to solve the decoupled equations.To unravel the original system,the inverse transform is applied.Decoupling the equations enables one to solve them based on the solution methods available for a single plate system.This also diminishes the computational costs of such problems.By considering different boundary conditions,a case study is run to present the method and to validate the results with its counterparts,for which excellent agreement is observed.Assessing the influence of dimensionless thickness,aspect ratio,and stiffness coefficients on the frequencies reveals the different effects of them at the low order of dimensionless natural frequencies in comparison with high orders and for different boundary conditions.展开更多
Habitat loss and fragmentation of the wildlife species due to anthropogenic developments have been becoming serious issues in biological conservation. Alborz wild sheep, listed as threatened by IUCN, is distributed in...Habitat loss and fragmentation of the wildlife species due to anthropogenic developments have been becoming serious issues in biological conservation. Alborz wild sheep, listed as threatened by IUCN, is distributed in relatively small and isolated patches in an increasingly human dominated landscape in the north-central Iran and east of Tehran. We used maximum entropy modeling to identify habitat areas of the wild sheep, across Jajrud protected area and its neighbouring protected areas including varjin, lar, koohsefid and the surroundings. Regarding to seasonal variation of the species home range, winter, summer and multi seasonal (annual) habitats were predicted. To estimate habitat connectivity, we used models of connectivity based in electrical circuit theory. Applying core areas of multi season for connectivity analysis, movement pattern of the species was predicted and important connective areas for conservation were identified. Species distribution maps revealed that the summer and winter habitats were approximately occurred in similar areas. Distance to eco-guards’ post was the most important predictor for both habitat models of summer and winter. The annual model, which is a combination of summer and winter, shows that the largest suitable habitat patches are located in the north, south and west of the study area. Maximum current flow map demonstrates that the areas among patch pairs are covered in low current, reflecting low rates of the species dispersal. This map presented bottlenecks to the species movement across major roads and along extending human settlements. Cumulative current flow map displayed that current was highest in Jajrud north of Mamloo extending to the northern Jajrud. Overall, our study demonstrated a prediction of habitat suitability and connectivity for Alborz wild sheep in east of Tehran, which can be used to direct conservation endeavours dealing with maintenance of the wild sheep metapopulation dynamics.展开更多
In the process of unconventional natural gas development practice,the"extreme utilization"concept that focuses on"continuously breaking through the limit of development technology"is gradually form...In the process of unconventional natural gas development practice,the"extreme utilization"concept that focuses on"continuously breaking through the limit of development technology"is gradually formed,and supports the scale benefit exploration of unconventional gas in China.On this basis,the development theory of"extreme utilization"is proposed,its theoretical connotation together with development technologies of unconventional natural gas are clarified.The theoretical connotation is that,aiming at"extreme gas reservoirs","extreme techniques"are utilized to build subsurface connected bodies,expand the discharge area,and enlarge the production range,to obtain the maximum single-well production,extreme recovery,and eventually achieve the"extreme effect"of production.The series of development technologies include micro/nano-scale reservoir evaluation,"sweet spot"prediction,unconventional percolation theory and production capacity evaluation,optimization of grid well pattern,optimal-fast drilling and volume fracturing,and working regulation optimization and"integrated"organizing system.The"extreme utilization"development theory has been successfully applied in the development of unconventional gas reservoirs such as Sulige tight gas,South Sichuan shale gas,and Qinshui coalbed methane.Such practices demonstrate that,the"extreme utilization"development theory has effectively promoted the development of unconventional gas industry in China,and can provide theoretical guidance for effective development of other potential unconventional and difficult-to-recovery resources.展开更多
The dynamic responses of two pontoons while connected with each other in irregular waves are calculated by means of three-dimensional (3-D) potential flow theory. The computation is to find the optimal status for co...The dynamic responses of two pontoons while connected with each other in irregular waves are calculated by means of three-dimensional (3-D) potential flow theory. The computation is to find the optimal status for connection at a certain sea state. On the basis of the relative motion of two pontoons in irregular waves, Visual FORTRAN programming language, as well as OpenGL (Open Graphics Library), is used to develop a set of virtual reality system of the relative motion of two pontoons, which is fully interactive with realistic effect. The transfinite interpolation scheme is applied for the mesh generation of wave surface, and the wave motion is simulated by surface elevation and calculated by 3-D potential flow theory.展开更多
On the basis of expounding the research results of using relevant knowledge about Game Theory for supply chain of agricultural products at home and abroad,we use principal-agent model in Game Theory to research the ne...On the basis of expounding the research results of using relevant knowledge about Game Theory for supply chain of agricultural products at home and abroad,we use principal-agent model in Game Theory to research the new function that the supermarkets entrust supervision and control over quality of agricultural products to agricultural brokers in the circulation model of connecting agriculture with supermarkets;then design the optimal incentive contract and influencing factors between agricultural broker and supermarket,and explain the fundamental role of agricultural brokers in the process of circulation;finally in light of the role of government in promoting development and application of agricultural brokers,put forward corresponding policy suggestions:establish government support policy;set relevant standard of industry;establish cooperative organizations of agricultural brokers.展开更多
Attacks on the cyber space is getting exponential in recent times.Illegal penetrations and breaches are real threats to the individuals and organizations.Conventional security systems are good enough to detect the kno...Attacks on the cyber space is getting exponential in recent times.Illegal penetrations and breaches are real threats to the individuals and organizations.Conventional security systems are good enough to detect the known threats but when it comes to Advanced Persistent Threats(APTs)they fails.These APTs are targeted,more sophisticated and very persistent and incorporates lot of evasive techniques to bypass the existing defenses.Hence,there is a need for an effective defense system that can achieve a complete reliance of security.To address the above-mentioned issues,this paper proposes a novel honeypot system that tracks the anonymous behavior of the APT threats.The key idea of honeypot leverages the concepts of graph theory to detect such targeted attacks.The proposed honey-pot is self-realizing,strategic assisted which withholds the APTs actionable tech-niques and observes the behavior for analysis and modelling.The proposed graph theory based self learning honeypot using the resultsγ(C(n,1)),γc(C(n,1)),γsc(C(n,1))outperforms traditional techniques by detecting APTs behavioral with detection rate of 96%.展开更多
In this paper, we investigate the connectivity of vehicular ad hoc networks in free-flow traffic situation with channel randonmess. In order to illustrate the realistic environment, we consider that vehicles are distr...In this paper, we investigate the connectivity of vehicular ad hoc networks in free-flow traffic situation with channel randonmess. In order to illustrate the realistic environment, we consider that vehicles are distributed in free-flow highway according to a Poisson point process, and signal propagation between connected vehicles is subjected to log-normal shadowing effects. We obtain the distribution of the space headway between successive vehicles and the distribution of signal coverage, which allows us to use the equivalent M/G/z~ queue theory to model the connectivity of VANETs in the form of average broadcast percolation distance and average number of connected nodes. Then, extensive simulation studies are conducted to evaluate the obtained results. The analytical model presented here is able to describe the impact of various system parameters, including traffic parameters and signal propagation parameters on the con- nectivity. We use our analytical results, along with the common signal propagation data, to understand impact of channel randomness on the connectivity of VANETs.展开更多
Recently, the inverse connected p-median problem on block graphs G(V,E,w) under various cost functions, say rectilinear norm, Chebyshev norm, and bottleneck Hamming distance. Their contributions include finding a nece...Recently, the inverse connected p-median problem on block graphs G(V,E,w) under various cost functions, say rectilinear norm, Chebyshev norm, and bottleneck Hamming distance. Their contributions include finding a necessary and sufficient condition for the connected p-median problem on block graphs, developing algorithms and showing that these problems can be solved in O(n log n) time, where n is the number of vertices in the underlying block graph. Using similar technique, we show that some results are incorrect by a counter-example. Then we redefine some notations, reprove Theorem 1 and redescribe Theorem 2, Theorem 3 and Theorem 4.展开更多
Teacher talk is of great significance in the classroom organization as well as the process of language acquisition.This paper explores the teacher talk from the angel of SLA Theories and analyzes the connection betwee...Teacher talk is of great significance in the classroom organization as well as the process of language acquisition.This paper explores the teacher talk from the angel of SLA Theories and analyzes the connection between teacher talk and SLA Theories.Thus it gives some suggestions to improve Teacher Talk in English classroom and consequently promotes students’second language acquisition.展开更多
Due to the rapid growth of the economy and society,the burden of social security has been increasingly escalating,resulting in a continuous rise in parenting stress among certain groups of parents.On one hand,these pa...Due to the rapid growth of the economy and society,the burden of social security has been increasingly escalating,resulting in a continuous rise in parenting stress among certain groups of parents.On one hand,these parents aspire for their young children to grow through play;on the other hand,they are acutely aware that early childhood education constitutes the foundational stage of basic education and serves as the commencement phase of lifelong learning.Thus,they recognize the importance of emphasizing early childhood education.Therefore,preschool education has been given important significance.Parents place particular emphasis on education during this stage.They actively leverage their educational,financial,and social advantages to create favorable educational resources and opportunities for their young children.However,to a certain extent,this exacerbates educational anxiety among a segment of parents.Despite the implementation of various governmental measures,it appears that these initiatives have not fundamentally addressed parental educational anxiety at its root.This study employs interview techniques and literature review methodologies to gain a profound understanding of parental educational anxiety during the transition from early childhood to primary education.By integrating Gesell's Maturation Theory,this research aims to scientifically explicate the developmental patterns of children.Consequently,it endeavors to enable non-professional parents to adopt a"professional"perspective in their approach towards early childhood education.展开更多
文摘This paper focused on investigating local tensile strength of connection between steel beam flange and concrete-filled circular column tube with through diaphragm. Three specimens were designed and tested to failure, and the structure behavior was studied by experiment and FEM analysis. On the basis of the results obtained, an estimation for local plastic and ultimate strengths of the connections using yield line theory was attempted, which results in a good prediction.
基金the Natural Science Foundation of Liaoning Province(No.20052151)the Innovative Team Program of Liaoning Educational Committee
文摘Synchronization of N different coupled chaotic systems with ring and chain connections is investigated. The New system, the Chen system, the Lii system, the Lorenz system, and the Rossler system are used as examples in verifying effectiveness of the method. Based on the Lyapunov stability theory, the form of the controller is designed and the area of the coupling coefficients is determined. Simulations indicate that global synchronization of the N different chaotic systems can be realized by choosing appropriate coupling coefficients by using the controller.
基金supported by the National Natural Science Foundation of China(Grant Nos.42271421 and 41930102)。
文摘Material exchange frequently occurs in gullies,and thus the relationship between a gullynetwork structure and sediment transport potential has attracted considerable interest.However,previous researches ignored the difficulty of material transport from sources to sinks,and did not quantify the connectivity of a network structure.In this study,we used a graph model structure to model gully networks of six typical sample areas in the Loess Plateau of China and quantified gully network connectivity using four indexes:average node strength,accessibility from sources to sinks,potential flow,and network structural connectivity index.Results show that:(1)Reflected by different quantitative indexes,the trends of gully network connectivity in different regions are similar.From north to south,the connectivity of a sample area first increases and then decreases.(2)The more mature gullies have stronger network connectivity.Small resistance is conducive to material transport in the gullies.(3)The node connectivity index of the gully network shows a significant aggregation distribution in space,and node connectivity on the main channel is often stronger than that on the branch trench.These results not only deepen the understanding of the process and mechanism of loess gully geomorphic development and evolution but also provide a reference for geomorphic studies.
文摘I show how many connections of Γ?are presently existing from R?to β?as they are being inputted simultaneously through tensor products. I plan to address the Quantum state of this tensor connection step by step throughout the application presented. Also, I will show you how to prove that the connection is true for this tensor connection through its output method using a small bit of tensor calculus and mostly number theory.
文摘Discourse connectives can be dealt with in relevance-theoretic terms, as indicators of types of relevance. These connectives can be used to constrain the interpretation of an utterance. They are analyzed in a broad classification outlined in discourse connectives which introduce contextual implications, which are concerned with strengthening and which introduce denials. A relevance based approach to discourse is a more adequate framework than a coherence based one for the analysis of discourse connectives.
文摘In this paper, we conduct research on the applications of advanced mathematics on the mathematical modeling and the inner connections with linear algebra and the probability statistics. Aiming at model in mathematical modeling and solving and model of evaluation and promotion of the two links, put forward the "bystander" and "the authorities" this two characters, and points out that excellent mathematical modeling participants should have "from a bystander to the authorities" and "from the authorities to return to bystanders" two-way role transformation ability. Great situation in mathematics teaching, by means of the mathematical modeling formed in the development of the teachers, as well as the teaching thought, teaching experience and achievements, the onward march of mathematical experiment should be faster than mathematical modeling. Our research provides the new paradigm for the math development which will be meaningful.
基金supported by the National Natural Science Foundation of China,Nos.81671671(to JL),61971451(to JL),U22A2034(to XK),62177047(to XK)the National Defense Science and Technology Collaborative Innovation Major Project of Central South University,No.2021gfcx05(to JL)+6 种基金Clinical Research Cen terfor Medical Imaging of Hunan Province,No.2020SK4001(to JL)Key Emergency Project of Pneumonia Epidemic of Novel Coronavirus Infection of Hu nan Province,No.2020SK3006(to JL)Innovative Special Construction Foundation of Hunan Province,No.2019SK2131(to JL)the Science and Technology lnnovation Program of Hunan Province,Nos.2021RC4016(to JL),2021SK53503(to ML)Scientific Research Program of Hunan Commission of Health,No.202209044797(to JL)Central South University Research Program of Advanced Interdisciplinary Studies,No.2023Q YJC020(to XK)the Natural Science Foundation of Hunan Province,No.2022JJ30814(to ML)。
文摘Patients with mild traumatic brain injury have a diverse clinical presentation,and the underlying pathophysiology remains poorly understood.Magnetic resonance imaging is a non-invasive technique that has been widely utilized to investigate neuro biological markers after mild traumatic brain injury.This approach has emerged as a promising tool for investigating the pathogenesis of mild traumatic brain injury.G raph theory is a quantitative method of analyzing complex networks that has been widely used to study changes in brain structure and function.However,most previous mild traumatic brain injury studies using graph theory have focused on specific populations,with limited exploration of simultaneous abnormalities in structural and functional connectivity.Given that mild traumatic brain injury is the most common type of traumatic brain injury encounte red in clinical practice,further investigation of the patient characteristics and evolution of structural and functional connectivity is critical.In the present study,we explored whether abnormal structural and functional connectivity in the acute phase could serve as indicators of longitudinal changes in imaging data and cognitive function in patients with mild traumatic brain injury.In this longitudinal study,we enrolled 46 patients with mild traumatic brain injury who were assessed within 2 wee ks of injury,as well as 36 healthy controls.Resting-state functional magnetic resonance imaging and diffusion-weighted imaging data were acquired for graph theoretical network analysis.In the acute phase,patients with mild traumatic brain injury demonstrated reduced structural connectivity in the dorsal attention network.More than 3 months of followup data revealed signs of recovery in structural and functional connectivity,as well as cognitive function,in 22 out of the 46 patients.Furthermore,better cognitive function was associated with more efficient networks.Finally,our data indicated that small-worldness in the acute stage could serve as a predictor of longitudinal changes in connectivity in patients with mild traumatic brain injury.These findings highlight the importance of integrating structural and functional connectivity in unde rstanding the occurrence and evolution of mild traumatic brain injury.Additionally,exploratory analysis based on subnetworks could serve a predictive function in the prognosis of patients with mild traumatic brain injury.
基金Educational and Teaching Reform Research Key Project of Xi’an University of Technology——Research and Practice of Course Ideological and Political Teaching Reform Under the Leadership of Party Building(XJY1911)Postgraduate Educational Reform Research Project of Xi’an University of Technology——Correlational and Simultaneous Research and Practice on Graduate Professional Courses and Ideological and Political Theory Courses.
文摘The integration of ideological and political curriculum which exists in colleges and compulsory education is a powerful guarantee for enhancing the effectiveness of the course.Putting theoretical content as well as teaching practice into effect contributes to every improvement and new idea about the curriculum.Facing the new circumstances,new tasks,and new challenges under the social background,it is necessary to reinforce the connection of the integration of the subject in universities and colleges and compulsory education,and take problems as the research direction for the sake of expanding the channels for courses ideological and political construction,and understand the integrated evolution of ideological and political theory courses of undergraduate and specialist education and compulsory education to a higher degree.Grasping the current situation and problems of the theory curriculum in colleges and compulsory education,and exploring the content of the theory in undergraduate and specialist education and compulsory education are of great significance,both in the integrated construction of ideological and political theory courses of undergraduate and specialist education and compulsory education and in making the best of the courses to implement the basic task of fostering people.
基金Iran National Science Foundation(INSF)under Grant No.97021731。
文摘A new procedure is proposed to ease the analyses of the free vibration of an elastically connected identical plates system with respect to Kirchhoff plate theory.A structure of n parallel,elastically connected rectangular plates is of concern,whereby the motion is explained by a set of n coupled partial differential equations.The method involves a new change in variables to uncouple equations and form an equal system of n decoupled plates,while each is assumed to be elastically connected to the ground.The differential quadrature method is adopted to solve the decoupled equations.To unravel the original system,the inverse transform is applied.Decoupling the equations enables one to solve them based on the solution methods available for a single plate system.This also diminishes the computational costs of such problems.By considering different boundary conditions,a case study is run to present the method and to validate the results with its counterparts,for which excellent agreement is observed.Assessing the influence of dimensionless thickness,aspect ratio,and stiffness coefficients on the frequencies reveals the different effects of them at the low order of dimensionless natural frequencies in comparison with high orders and for different boundary conditions.
文摘Habitat loss and fragmentation of the wildlife species due to anthropogenic developments have been becoming serious issues in biological conservation. Alborz wild sheep, listed as threatened by IUCN, is distributed in relatively small and isolated patches in an increasingly human dominated landscape in the north-central Iran and east of Tehran. We used maximum entropy modeling to identify habitat areas of the wild sheep, across Jajrud protected area and its neighbouring protected areas including varjin, lar, koohsefid and the surroundings. Regarding to seasonal variation of the species home range, winter, summer and multi seasonal (annual) habitats were predicted. To estimate habitat connectivity, we used models of connectivity based in electrical circuit theory. Applying core areas of multi season for connectivity analysis, movement pattern of the species was predicted and important connective areas for conservation were identified. Species distribution maps revealed that the summer and winter habitats were approximately occurred in similar areas. Distance to eco-guards’ post was the most important predictor for both habitat models of summer and winter. The annual model, which is a combination of summer and winter, shows that the largest suitable habitat patches are located in the north, south and west of the study area. Maximum current flow map demonstrates that the areas among patch pairs are covered in low current, reflecting low rates of the species dispersal. This map presented bottlenecks to the species movement across major roads and along extending human settlements. Cumulative current flow map displayed that current was highest in Jajrud north of Mamloo extending to the northern Jajrud. Overall, our study demonstrated a prediction of habitat suitability and connectivity for Alborz wild sheep in east of Tehran, which can be used to direct conservation endeavours dealing with maintenance of the wild sheep metapopulation dynamics.
基金Supported by the China National Science and Technology Major Project(2017ZX05035,2016ZX05037)。
文摘In the process of unconventional natural gas development practice,the"extreme utilization"concept that focuses on"continuously breaking through the limit of development technology"is gradually formed,and supports the scale benefit exploration of unconventional gas in China.On this basis,the development theory of"extreme utilization"is proposed,its theoretical connotation together with development technologies of unconventional natural gas are clarified.The theoretical connotation is that,aiming at"extreme gas reservoirs","extreme techniques"are utilized to build subsurface connected bodies,expand the discharge area,and enlarge the production range,to obtain the maximum single-well production,extreme recovery,and eventually achieve the"extreme effect"of production.The series of development technologies include micro/nano-scale reservoir evaluation,"sweet spot"prediction,unconventional percolation theory and production capacity evaluation,optimization of grid well pattern,optimal-fast drilling and volume fracturing,and working regulation optimization and"integrated"organizing system.The"extreme utilization"development theory has been successfully applied in the development of unconventional gas reservoirs such as Sulige tight gas,South Sichuan shale gas,and Qinshui coalbed methane.Such practices demonstrate that,the"extreme utilization"development theory has effectively promoted the development of unconventional gas industry in China,and can provide theoretical guidance for effective development of other potential unconventional and difficult-to-recovery resources.
基金supported by the National Natural Science Foundation of China(Grant No.50579047)
文摘The dynamic responses of two pontoons while connected with each other in irregular waves are calculated by means of three-dimensional (3-D) potential flow theory. The computation is to find the optimal status for connection at a certain sea state. On the basis of the relative motion of two pontoons in irregular waves, Visual FORTRAN programming language, as well as OpenGL (Open Graphics Library), is used to develop a set of virtual reality system of the relative motion of two pontoons, which is fully interactive with realistic effect. The transfinite interpolation scheme is applied for the mesh generation of wave surface, and the wave motion is simulated by surface elevation and calculated by 3-D potential flow theory.
基金Supported by National College Students Innovation Program in 2009(091029532)
文摘On the basis of expounding the research results of using relevant knowledge about Game Theory for supply chain of agricultural products at home and abroad,we use principal-agent model in Game Theory to research the new function that the supermarkets entrust supervision and control over quality of agricultural products to agricultural brokers in the circulation model of connecting agriculture with supermarkets;then design the optimal incentive contract and influencing factors between agricultural broker and supermarket,and explain the fundamental role of agricultural brokers in the process of circulation;finally in light of the role of government in promoting development and application of agricultural brokers,put forward corresponding policy suggestions:establish government support policy;set relevant standard of industry;establish cooperative organizations of agricultural brokers.
文摘Attacks on the cyber space is getting exponential in recent times.Illegal penetrations and breaches are real threats to the individuals and organizations.Conventional security systems are good enough to detect the known threats but when it comes to Advanced Persistent Threats(APTs)they fails.These APTs are targeted,more sophisticated and very persistent and incorporates lot of evasive techniques to bypass the existing defenses.Hence,there is a need for an effective defense system that can achieve a complete reliance of security.To address the above-mentioned issues,this paper proposes a novel honeypot system that tracks the anonymous behavior of the APT threats.The key idea of honeypot leverages the concepts of graph theory to detect such targeted attacks.The proposed honey-pot is self-realizing,strategic assisted which withholds the APTs actionable tech-niques and observes the behavior for analysis and modelling.The proposed graph theory based self learning honeypot using the resultsγ(C(n,1)),γc(C(n,1)),γsc(C(n,1))outperforms traditional techniques by detecting APTs behavioral with detection rate of 96%.
基金Supported by the National Natural Science Foundation of China (No. 60873192,61070182)
文摘In this paper, we investigate the connectivity of vehicular ad hoc networks in free-flow traffic situation with channel randonmess. In order to illustrate the realistic environment, we consider that vehicles are distributed in free-flow highway according to a Poisson point process, and signal propagation between connected vehicles is subjected to log-normal shadowing effects. We obtain the distribution of the space headway between successive vehicles and the distribution of signal coverage, which allows us to use the equivalent M/G/z~ queue theory to model the connectivity of VANETs in the form of average broadcast percolation distance and average number of connected nodes. Then, extensive simulation studies are conducted to evaluate the obtained results. The analytical model presented here is able to describe the impact of various system parameters, including traffic parameters and signal propagation parameters on the con- nectivity. We use our analytical results, along with the common signal propagation data, to understand impact of channel randomness on the connectivity of VANETs.
文摘Recently, the inverse connected p-median problem on block graphs G(V,E,w) under various cost functions, say rectilinear norm, Chebyshev norm, and bottleneck Hamming distance. Their contributions include finding a necessary and sufficient condition for the connected p-median problem on block graphs, developing algorithms and showing that these problems can be solved in O(n log n) time, where n is the number of vertices in the underlying block graph. Using similar technique, we show that some results are incorrect by a counter-example. Then we redefine some notations, reprove Theorem 1 and redescribe Theorem 2, Theorem 3 and Theorem 4.
文摘Teacher talk is of great significance in the classroom organization as well as the process of language acquisition.This paper explores the teacher talk from the angel of SLA Theories and analyzes the connection between teacher talk and SLA Theories.Thus it gives some suggestions to improve Teacher Talk in English classroom and consequently promotes students’second language acquisition.
文摘Due to the rapid growth of the economy and society,the burden of social security has been increasingly escalating,resulting in a continuous rise in parenting stress among certain groups of parents.On one hand,these parents aspire for their young children to grow through play;on the other hand,they are acutely aware that early childhood education constitutes the foundational stage of basic education and serves as the commencement phase of lifelong learning.Thus,they recognize the importance of emphasizing early childhood education.Therefore,preschool education has been given important significance.Parents place particular emphasis on education during this stage.They actively leverage their educational,financial,and social advantages to create favorable educational resources and opportunities for their young children.However,to a certain extent,this exacerbates educational anxiety among a segment of parents.Despite the implementation of various governmental measures,it appears that these initiatives have not fundamentally addressed parental educational anxiety at its root.This study employs interview techniques and literature review methodologies to gain a profound understanding of parental educational anxiety during the transition from early childhood to primary education.By integrating Gesell's Maturation Theory,this research aims to scientifically explicate the developmental patterns of children.Consequently,it endeavors to enable non-professional parents to adopt a"professional"perspective in their approach towards early childhood education.