In order to save the energy and reduce the latency of the end-to-end transmission in mobile ad hoc networks an adaptive and distance-driven power control ADPC scheme is proposed by means of distance research in random...In order to save the energy and reduce the latency of the end-to-end transmission in mobile ad hoc networks an adaptive and distance-driven power control ADPC scheme is proposed by means of distance research in random geometrics. Through mathematical proof the optimal number of relay nodes and the optimal location of each node for data transmission can be obtained when a distance is given.In the ADPC first the source node computes the optimal number and the sites of the relay nodes between the source and the destination nodes.Then it searches feasible relay nodes around the optimal virtual relay-sites and selects one link with the minimal total transmission energy consumption for data transmission.Simulation results show that the ADPC can reduce both the energy dissipation and the end-to-end latency of the transmission.展开更多
The conventional linear quadratic regulator(LQR) control algorithm is one of the most popular active control algorithms.One important issue for LQR control algorithm is the reduction of structure's degrees of free...The conventional linear quadratic regulator(LQR) control algorithm is one of the most popular active control algorithms.One important issue for LQR control algorithm is the reduction of structure's degrees of freedom(DOF). In this work, an LQR control algorithm with superelement model is intended to solve this issue leading to the fact that LQR control algorithm can be used in large finite element(FE) model for structure. In proposed model, the Craig-Bampton(C-B) method, which is one of the component mode syntheses(CMS), is used to establish superelement modeling to reduce structure's DOF and applied to LQR control algorithm to calculate Kalman gain matrix and obtain control forces. And then, the control forces are applied to original structure to simulate the responses of structure by vibration control. And some examples are given. The results show the computational efficiency of proposed model using synthesized models is higher than that of the classical method of LQR control when the DOF of structure is large. And the accuracy of proposed model is well. Meanwhile, the results show that the proposed control has more effects of vibration absorption on the ground structures than underground structures.展开更多
MANET routing is critical and routing decision should be made sooner before the node leaves the network.Fast decisions always compensate network performance.In addition,most MANET routing protocols assume a friendly a...MANET routing is critical and routing decision should be made sooner before the node leaves the network.Fast decisions always compensate network performance.In addition,most MANET routing protocols assume a friendly and cooperative environment,and hence are vulnerable to various attacks.Trust and Reputation would serve as a major solution to these problems.Learning the network characteristics and choosing right routing decisions at right times would be a significant solution.In this work,we have done an extensive survey of fault tolerant protocols and ant colony algorithms applied to routing in MANETs.We propose a QoS constrained fault tolerant ant lookahead routing algorithm which attempts to identify valid route and look-ahead route pairs which might help in choosing the alternate path in case of valid route failure.The results prove that the proposed algorithm takes better routing decisions with 20-30 percent improvement compared with existing ant colony algorithms.展开更多
Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective ...Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.展开更多
This paper is devoted to investigating exact solutions of a generalized fractional nonlinear anomalousdiffusion equation in radical symmetry.The presence of external force and absorption is also considered.We firstinv...This paper is devoted to investigating exact solutions of a generalized fractional nonlinear anomalousdiffusion equation in radical symmetry.The presence of external force and absorption is also considered.We firstinvestigate the nonlinear anomalous diffusion equations with one-fractional derivative and then multi-fractional ones.Inboth situations,we obtain the corresponding exact solutions,and the solutions found here can have a compact behavioror a long tailed behavior.展开更多
This paper is organized as follows. After a discussion of the differential equations for wave propagation in the horizontally stratified medium and of the initial and boundary conditions, the displacements are derived...This paper is organized as follows. After a discussion of the differential equations for wave propagation in the horizontally stratified medium and of the initial and boundary conditions, the displacements are derived on the free surface of the layered medium for plane waves when a point source is located on the s-th imaginary boundary at the depth -s (physical parameters of the layers s and (s + 1) are put to be identical). Then, the source will be represented as a single force of arbitrary orientation and a general moment tensor point source. Further, "a primary field" for a point source will be introduced. Matrix method for the solution of the direct seismic problem is considered based on the matrix method of Thomson-Haskell and its modifications.展开更多
The scalability of routing architectures for large networks is one of the biggest challenges that the Internet faces today.Greedy routing,in which each node is assigned a locator used as a distance metric,recently rec...The scalability of routing architectures for large networks is one of the biggest challenges that the Internet faces today.Greedy routing,in which each node is assigned a locator used as a distance metric,recently received increased attention from researchers and is considered as a potential solution for scalable routing.In this paper,LMD—a local minimum driven method is proposed to compute the topology-based locator.To eliminate the negative effect of the " quasi" greedy property—transfer routes longer than the shortest routes,a two-stage routing strategy is introduced,which combines the greedy routing with source routing.The greedy routing path discovered and compressed in the first stage is then used by the following source-routing stage.Through extensive evaluations,based on synthetic topologies as well as on a snapshot of the real Internet AS(autonomous system)topology,it is shown that LMD guarantees 100%delivery rate on large networks with low stretch.展开更多
The aim of this paper is the introduction of a new approach to 3D modelling of elastic piecewise homogeneous media, in particular Earth crust and upper Mantle. The method is based on the principle of tomography with E...The aim of this paper is the introduction of a new approach to 3D modelling of elastic piecewise homogeneous media, in particular Earth crust and upper Mantle. The method is based on the principle of tomography with Earthquake as a source of the signal and receiver stations on the surface. The wave propagation in solid media is described by a system of three strongly coupled hyperbolic equations with piece - wise constant coefitients. The characteristic set and hi-characteristic curves of this system are computed in a homogeneous half-space with free boundary and the formulae of reflection and diffraction of the hi-characteristics on the internal boundaries of the media. Applications of the characteristic set and bi-eharacteristic curves for the inverse problem in geophysics and Earth modelling are given.展开更多
The Trump administration's hostile trade actions against China since the beginning of this year violate World Trade Organization rules. To protect the free trade world economic system, China has stood up to fight ...The Trump administration's hostile trade actions against China since the beginning of this year violate World Trade Organization rules. To protect the free trade world economic system, China has stood up to fight this trade bullying. When the US administration continued with harsher actions, the escalation in trade friction increased the potential harm for both countries. China has been very clear that Trump's trade tariffs cannot improve the bilateral trade imbalance. Tit-for-tat ought to be a last resort but China is open to talking. Now the ball is in Trump's court. As two big,influential economies, China and the US should calm down and go back to negotiating table to avoid a trade war trap. Bullying is only one approach President Trump can choose, but arbitrary threats are no solution.展开更多
The word globalization and what it stands for is no longer new in the world of today. However, there is still no universal definition of globalization. This has led to erroneously or otherwise, the interchangeable use...The word globalization and what it stands for is no longer new in the world of today. However, there is still no universal definition of globalization. This has led to erroneously or otherwise, the interchangeable use of the word with internationalization and liberalization. Suffice it therefore to say that globalization is the transcendence of the economic, political, environmental, social and cultural constraints across territories. The task of this paper is essentially to ascertain the level of involvement of Africa via Nigeria in this new international economic power and order. This is necessary because Nigeria particularly, has become a good consumer of information technology which is an essential ingredient of globalization. The issue then is how prepared are the Nigerian languages in the challenges of information technology as demanded by globalization. What are the implications of the order to Nigerian cultural revival and development?展开更多
A facile and efficient synthesis of N-sulfonyl-N,N-disubstituted amidines has been achieved via a CuI-catalyzed three-component free-radical coupling reaction of tertiary amines and arenesulfonyl azides with terminal ...A facile and efficient synthesis of N-sulfonyl-N,N-disubstituted amidines has been achieved via a CuI-catalyzed three-component free-radical coupling reaction of tertiary amines and arenesulfonyl azides with terminal alkynes in the presence of azodiisobutyronitrile(AIBN).The reaction mechanism of this reaction has also been studied.展开更多
A new model used to calculate the free energy change of protein unfolding is presented. In this model, proteins are considered to be composed of structural elements. The unfolding of a structural element obeys a two-s...A new model used to calculate the free energy change of protein unfolding is presented. In this model, proteins are considered to be composed of structural elements. The unfolding of a structural element obeys a two-state mechanism and the free energy change of the element can be obtained by a linear extrapolation method. If a protein consists of the same structural elements, its unfolding will displays a two-state process, and only the average structural element free energy change 〈△G0 element(H2O)〉 can be measured. If protein consists of completely different structural elements, its unfolding will show a multi-state behavior. When a protein consists of n structural elements its unfolding will shows a (n+1)-state behavior. A least-squares fitting can be used to analyze the contribution of each structural element to the protein and the free energy change of each structural element can be obtained by using linear extrapolation to zero denaturant concentration, not to the start of each transition. The measured △Gn protein(H2O) is the sum of the free energy change for each structural element. Using this new model, we can not only analyze the stability of various proteins with similar structure and similar molecular weight, which undergo multi-state unfolding processes, but also compare the stability of proteins with different structures and molecular weights using the average structural element free energy change 〈△G0 element(H2O)〉. Although this method cannot completely provide the exact free energy of proteins, it is better than current methods.展开更多
基金The National Basic Research Program of China(973 Program)(No.2009CB320501)the National Natural Science Foundation of China(No.61370209,61272532)the Natural Science Foundation of Jiangsu Province(No.BK2010414,BK2011335)
文摘In order to save the energy and reduce the latency of the end-to-end transmission in mobile ad hoc networks an adaptive and distance-driven power control ADPC scheme is proposed by means of distance research in random geometrics. Through mathematical proof the optimal number of relay nodes and the optimal location of each node for data transmission can be obtained when a distance is given.In the ADPC first the source node computes the optimal number and the sites of the relay nodes between the source and the destination nodes.Then it searches feasible relay nodes around the optimal virtual relay-sites and selects one link with the minimal total transmission energy consumption for data transmission.Simulation results show that the ADPC can reduce both the energy dissipation and the end-to-end latency of the transmission.
基金Project(LZ2015022)supported by Educational Commission of Liaoning Province of ChinaProjects(51138001,51178081)supported by the National Natural Science Foundation of China+1 种基金Project(2013CB035905)supported by the Basic Research Program of ChinaProjects(DUT15LK34,DUT14QY10)supported by Fundamental Research Funds for the Central Universities,China
文摘The conventional linear quadratic regulator(LQR) control algorithm is one of the most popular active control algorithms.One important issue for LQR control algorithm is the reduction of structure's degrees of freedom(DOF). In this work, an LQR control algorithm with superelement model is intended to solve this issue leading to the fact that LQR control algorithm can be used in large finite element(FE) model for structure. In proposed model, the Craig-Bampton(C-B) method, which is one of the component mode syntheses(CMS), is used to establish superelement modeling to reduce structure's DOF and applied to LQR control algorithm to calculate Kalman gain matrix and obtain control forces. And then, the control forces are applied to original structure to simulate the responses of structure by vibration control. And some examples are given. The results show the computational efficiency of proposed model using synthesized models is higher than that of the classical method of LQR control when the DOF of structure is large. And the accuracy of proposed model is well. Meanwhile, the results show that the proposed control has more effects of vibration absorption on the ground structures than underground structures.
文摘MANET routing is critical and routing decision should be made sooner before the node leaves the network.Fast decisions always compensate network performance.In addition,most MANET routing protocols assume a friendly and cooperative environment,and hence are vulnerable to various attacks.Trust and Reputation would serve as a major solution to these problems.Learning the network characteristics and choosing right routing decisions at right times would be a significant solution.In this work,we have done an extensive survey of fault tolerant protocols and ant colony algorithms applied to routing in MANETs.We propose a QoS constrained fault tolerant ant lookahead routing algorithm which attempts to identify valid route and look-ahead route pairs which might help in choosing the alternate path in case of valid route failure.The results prove that the proposed algorithm takes better routing decisions with 20-30 percent improvement compared with existing ant colony algorithms.
基金This work is supported by the NSFC (National Natural Science Foundation of China) No. 61371068 and No. 61172130, the National 863 program No.2011AA11A102-04-02 and Shenzhen Technology Research and Development Program No. CXZZ20120830100839333.
文摘Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.
基金Supported by National Natural Science Foundation of China under Grant No.60641006the National Science Foundation of Shandong Province under Grant No.Y2007A06
文摘This paper is devoted to investigating exact solutions of a generalized fractional nonlinear anomalousdiffusion equation in radical symmetry.The presence of external force and absorption is also considered.We firstinvestigate the nonlinear anomalous diffusion equations with one-fractional derivative and then multi-fractional ones.Inboth situations,we obtain the corresponding exact solutions,and the solutions found here can have a compact behavioror a long tailed behavior.
文摘This paper is organized as follows. After a discussion of the differential equations for wave propagation in the horizontally stratified medium and of the initial and boundary conditions, the displacements are derived on the free surface of the layered medium for plane waves when a point source is located on the s-th imaginary boundary at the depth -s (physical parameters of the layers s and (s + 1) are put to be identical). Then, the source will be represented as a single force of arbitrary orientation and a general moment tensor point source. Further, "a primary field" for a point source will be introduced. Matrix method for the solution of the direct seismic problem is considered based on the matrix method of Thomson-Haskell and its modifications.
基金Supported by the National High Technology Research and Development Program of China(No.2013AA013501)the National Program on Key Basic Research Project(No.2012CB315801)+1 种基金the National Natural Science Foundation of China(No.61133015)the Science and Technology on Information Transmission and Dissemination in Communication Networks Laboratory,CETC54
文摘The scalability of routing architectures for large networks is one of the biggest challenges that the Internet faces today.Greedy routing,in which each node is assigned a locator used as a distance metric,recently received increased attention from researchers and is considered as a potential solution for scalable routing.In this paper,LMD—a local minimum driven method is proposed to compute the topology-based locator.To eliminate the negative effect of the " quasi" greedy property—transfer routes longer than the shortest routes,a two-stage routing strategy is introduced,which combines the greedy routing with source routing.The greedy routing path discovered and compressed in the first stage is then used by the following source-routing stage.Through extensive evaluations,based on synthetic topologies as well as on a snapshot of the real Internet AS(autonomous system)topology,it is shown that LMD guarantees 100%delivery rate on large networks with low stretch.
文摘The aim of this paper is the introduction of a new approach to 3D modelling of elastic piecewise homogeneous media, in particular Earth crust and upper Mantle. The method is based on the principle of tomography with Earthquake as a source of the signal and receiver stations on the surface. The wave propagation in solid media is described by a system of three strongly coupled hyperbolic equations with piece - wise constant coefitients. The characteristic set and hi-characteristic curves of this system are computed in a homogeneous half-space with free boundary and the formulae of reflection and diffraction of the hi-characteristics on the internal boundaries of the media. Applications of the characteristic set and bi-eharacteristic curves for the inverse problem in geophysics and Earth modelling are given.
文摘The Trump administration's hostile trade actions against China since the beginning of this year violate World Trade Organization rules. To protect the free trade world economic system, China has stood up to fight this trade bullying. When the US administration continued with harsher actions, the escalation in trade friction increased the potential harm for both countries. China has been very clear that Trump's trade tariffs cannot improve the bilateral trade imbalance. Tit-for-tat ought to be a last resort but China is open to talking. Now the ball is in Trump's court. As two big,influential economies, China and the US should calm down and go back to negotiating table to avoid a trade war trap. Bullying is only one approach President Trump can choose, but arbitrary threats are no solution.
文摘The word globalization and what it stands for is no longer new in the world of today. However, there is still no universal definition of globalization. This has led to erroneously or otherwise, the interchangeable use of the word with internationalization and liberalization. Suffice it therefore to say that globalization is the transcendence of the economic, political, environmental, social and cultural constraints across territories. The task of this paper is essentially to ascertain the level of involvement of Africa via Nigeria in this new international economic power and order. This is necessary because Nigeria particularly, has become a good consumer of information technology which is an essential ingredient of globalization. The issue then is how prepared are the Nigerian languages in the challenges of information technology as demanded by globalization. What are the implications of the order to Nigerian cultural revival and development?
基金National Natural Science Foundation of China (20872001)the Anhui Education Department (TD200707 & KJ2008A064)+1 种基金the Program for the NCET (NCET-10-0004)the Research Culture Funds of Anhui Normal University (2010rcpy041) for their financial support
文摘A facile and efficient synthesis of N-sulfonyl-N,N-disubstituted amidines has been achieved via a CuI-catalyzed three-component free-radical coupling reaction of tertiary amines and arenesulfonyl azides with terminal alkynes in the presence of azodiisobutyronitrile(AIBN).The reaction mechanism of this reaction has also been studied.
基金supported by the National Natural Science Foundation of China (20771068 and 20901048)the PhD Programs Foundation of the Ministry of Education of China (20091401110007)
文摘A new model used to calculate the free energy change of protein unfolding is presented. In this model, proteins are considered to be composed of structural elements. The unfolding of a structural element obeys a two-state mechanism and the free energy change of the element can be obtained by a linear extrapolation method. If a protein consists of the same structural elements, its unfolding will displays a two-state process, and only the average structural element free energy change 〈△G0 element(H2O)〉 can be measured. If protein consists of completely different structural elements, its unfolding will show a multi-state behavior. When a protein consists of n structural elements its unfolding will shows a (n+1)-state behavior. A least-squares fitting can be used to analyze the contribution of each structural element to the protein and the free energy change of each structural element can be obtained by using linear extrapolation to zero denaturant concentration, not to the start of each transition. The measured △Gn protein(H2O) is the sum of the free energy change for each structural element. Using this new model, we can not only analyze the stability of various proteins with similar structure and similar molecular weight, which undergo multi-state unfolding processes, but also compare the stability of proteins with different structures and molecular weights using the average structural element free energy change 〈△G0 element(H2O)〉. Although this method cannot completely provide the exact free energy of proteins, it is better than current methods.