Frequent inter-satellite link(ISL)handovers will induce service interruption in large-scale space information networks,since traditional distributed/centralized routing strategy-based route convergence/update will con...Frequent inter-satellite link(ISL)handovers will induce service interruption in large-scale space information networks,since traditional distributed/centralized routing strategy-based route convergence/update will consume considerable time(compared with ground networks)derived from long ISL delay and flooding between hundreds or even thousands of satellites.During the network convergence/update stage,the lack of up-to-date forwarding information may cause severe packet loss.Considering the fact that ISL handovers for close-to-earth constellation are predictable and all the ISL handover information could be stored in each satellite during the network initialization,we propose a self-update routing scheme based on open shortest path first(OSPF-SUR)to address the slow route convergence problem caused by frequent ISL handovers.First,for predictable ISL handovers,forwarding tables are updated according to locally stored ISL handover information without link state advertisement(LSA)flooding.Second,for unexpected ISL failures,flooding could be triggered to complete route convergence.In this manner,network convergence time is radically descended by avoiding unnecessary LSA flooding for predictable ISL handovers.Simulation results show that the average packet loss rate caused by ISL handovers is reduced by 90.5%and 61.3%compared with standard OSPF(with three Hello packets confirmation)and OSPF based on interface state(without three Hello packets confirmation),respectively,during a period of topology handover.And the average endto-end delay is also decreased by 47.6%,9.6%,respectively.The packet loss rate of the proposed OSPF-SUR does not change along with the increase of the frequency of topology handovers.展开更多
In order to form an algorithm for distribution network routing,an automatic routing method of distribution network planning was proposed based on the shortest path.The problem of automatic routing was divided into two...In order to form an algorithm for distribution network routing,an automatic routing method of distribution network planning was proposed based on the shortest path.The problem of automatic routing was divided into two steps in the method:the first step was that the shortest paths along streets between substation and load points were found by the basic ant colony algorithm to form a preliminary radial distribution network,and the second step was that the result of the shortest path was used to initialize pheromone concentration and pheromone updating rules to generate globally optimal distribution network.Cases studies show that the proposed method is effective and can meet the planning requirements.It is verified that the proposed method has better solution and utility than planning method based on the ant colony algorithm.展开更多
In location-aided routing of Mobile Ad hoc NETworks(MANET),nodes mobility and the inaccuracy of location information may result in constant flooding,which will reduce the network performance.In this paper,a Distance-B...In location-aided routing of Mobile Ad hoc NETworks(MANET),nodes mobility and the inaccuracy of location information may result in constant flooding,which will reduce the network performance.In this paper,a Distance-Based Location-Aided Routing(DBLAR) for MANET has been proposed.By tracing the location information of destination nodes and referring to distance change between nodes to adjust route discovery dynamically,the proposed routing algorithm can avoid flooding in the whole networks.Besides,Distance Update Threshold(DUT) is set up to reach the balance between real-time ability and update overhead of location information of nodes,meanwhile,the detection of relative distance vector can achieve the goal of adjusting forwarding condition.Simulation results reveal that DBLAR performs better than LAR1 in terms of packet successful delivery ratio,average end-to-end delay and routing-load,and the set of DUT and relative distance vector has a significant impact on this algorithm.展开更多
A novel technique called the bitmap lattice index(BLI) is proposed, which combines the advantages of a wireless broadcasting environment with a road network. Existing road networks are based on the on-demand method: a...A novel technique called the bitmap lattice index(BLI) is proposed, which combines the advantages of a wireless broadcasting environment with a road network. Existing road networks are based on the on-demand method: a server's workload increases as the query request increases when a server sends a client information. To solve this problem, we propose the BLI. The BLI denotes an object and a node as 0 and 1 in the Hilbert curve(HC) map. The BLI can identify the position of a node and an object through bit information; it can also reduce the broadcasting frequency of a server by reducing the size of the index, thereby decreasing the access latency and query processing times. Moreover, the BLI is highly effective for data filtering, as it can identify the positions of both an object and a node. In a road network, if filtering is done via the Euclidean distance, it may result in an error. To prevent this, we add another validation procedure. The experiment is conducted by applying the BLI to kNN query, and the technique is assessed by a performance evaluation experiment.展开更多
Road geometric design data are a vital input for diverse transportation studies. This information is usually obtained from the road design project. However, these are not always available and the as-built course of th...Road geometric design data are a vital input for diverse transportation studies. This information is usually obtained from the road design project. However, these are not always available and the as-built course of the road may diverge considerably from its projected one, rendering subsequent studies inaccurate or impossible. Moreover, the systematic acquisition of this data for the entire road network of a country or even a state represents a very challenging and laborious task. This study＇s goal was the extraction of geometric design data for the paved segments of the Brazilian federal highway network, containing more than 47,000 km of highways. It presents the details of the method＇s adoption process, the particularities of its application to the dataset and the obtained geometric design information. Additionally, it provides a first overview of the Brazilian federal highway network composition （curves and tangents） and geometry.展开更多
Opportunistic networks are random networks and do not communicate with each other among respective communication areas.This situation leads to great difficulty in message transfer.This paper proposes a reducing energy...Opportunistic networks are random networks and do not communicate with each other among respective communication areas.This situation leads to great difficulty in message transfer.This paper proposes a reducing energy consumption optimal selection of path transmission(OSPT) routing algorithm in opportunistic networks.This algorithm designs a dynamic random network topology,creates a dynamic link,and realizes an optimized selected path.This algorithm solves a problem that nodes are unable to deliver messages for a long time in opportunistic networks.According to the simulation experiment,OSPT improves deliver ratio,and reduces energy consumption,cache time and transmission delay compared with the Epidemic Algorithm and Spray and Wait Algorithm in opportunistic networks.展开更多
The paper design mobile information collection system based on lnternet of Things, implemented access gateway by smart mobile devices through a variety of ways, such as Wi-Fi and access the underlying perceptual infor...The paper design mobile information collection system based on lnternet of Things, implemented access gateway by smart mobile devices through a variety of ways, such as Wi-Fi and access the underlying perceptual information based on ZigBee wireless sensor networks. On the one hand, For information sensitivity of the sensor network, we design the mobile terminal through the gateway access authentication protocol, and effective solute the authentication and infbnnation between mobile devices and gateways, gateway and sensor network nodes obtain permission problem; on the other hand, according to the practical application of mobile information collection characteristics, the paper proposed information collection strategy based on historical data movement path to solve the problem for too long the device connection is established when the mobile smart devices collecting information along fixed lines, increasing the actual data transmission time and improve the efficiency of information transmission.展开更多
Internal control is a hot topic at present academics and for practitioners to explore. Especially under the background of China＇ s rapid integration into the global economy, the rapid establishment and improvement of...Internal control is a hot topic at present academics and for practitioners to explore. Especially under the background of China＇ s rapid integration into the global economy, the rapid establishment and improvement of the context of the modem enterprise system, the issue is of utmost importance. The internal accounting control system is the core part of internal control, which determines the extent of establishing the entire sound internal control system, With the progress of the time, the rapid development and wide application of Internet technology has changed the survival environment and management philosophy for business. The development of network technology achieves the online office, mobile office and decentralized offices, etc. Accounting entity is no longer subject to space limitations of traditional methods, thus a large number of accounting information is transmitted tbaough the network communication lines, so that accounting activities can be extended to every node in the world, which achieves the purpose of remote processing. Under the network environment, sources of information are of diversity and multi-channel. A large number of accounting information transmitted from the network communication lines is likely to be illegally intercepted, stolen and tampered by molecules or people with ulterior motives.展开更多
基金the National Natural Science Foundations of China(Nos.61771074,62171059)。
文摘Frequent inter-satellite link(ISL)handovers will induce service interruption in large-scale space information networks,since traditional distributed/centralized routing strategy-based route convergence/update will consume considerable time(compared with ground networks)derived from long ISL delay and flooding between hundreds or even thousands of satellites.During the network convergence/update stage,the lack of up-to-date forwarding information may cause severe packet loss.Considering the fact that ISL handovers for close-to-earth constellation are predictable and all the ISL handover information could be stored in each satellite during the network initialization,we propose a self-update routing scheme based on open shortest path first(OSPF-SUR)to address the slow route convergence problem caused by frequent ISL handovers.First,for predictable ISL handovers,forwarding tables are updated according to locally stored ISL handover information without link state advertisement(LSA)flooding.Second,for unexpected ISL failures,flooding could be triggered to complete route convergence.In this manner,network convergence time is radically descended by avoiding unnecessary LSA flooding for predictable ISL handovers.Simulation results show that the average packet loss rate caused by ISL handovers is reduced by 90.5%and 61.3%compared with standard OSPF(with three Hello packets confirmation)and OSPF based on interface state(without three Hello packets confirmation),respectively,during a period of topology handover.And the average endto-end delay is also decreased by 47.6%,9.6%,respectively.The packet loss rate of the proposed OSPF-SUR does not change along with the increase of the frequency of topology handovers.
基金Project(2009CB219703) supported by the National Basic Research Program of ChinaProject(2011AA05A117) supported by the National High Technology Research and Development Program of China
文摘In order to form an algorithm for distribution network routing,an automatic routing method of distribution network planning was proposed based on the shortest path.The problem of automatic routing was divided into two steps in the method:the first step was that the shortest paths along streets between substation and load points were found by the basic ant colony algorithm to form a preliminary radial distribution network,and the second step was that the result of the shortest path was used to initialize pheromone concentration and pheromone updating rules to generate globally optimal distribution network.Cases studies show that the proposed method is effective and can meet the planning requirements.It is verified that the proposed method has better solution and utility than planning method based on the ant colony algorithm.
基金Supported by National 863 High Technology Research and Development Program Foundation of China (No.2006AA-01Z208)Six Talented Eminence Foundation of Jiangsu Province (06-E-043), China+1 种基金Natural Science Foundation of Jiangsu Province, China (No.BK2007236)Scientific Innovation Project for Postgraduates of Universities in Jiangsu Province (CX08B-082Z)
文摘In location-aided routing of Mobile Ad hoc NETworks(MANET),nodes mobility and the inaccuracy of location information may result in constant flooding,which will reduce the network performance.In this paper,a Distance-Based Location-Aided Routing(DBLAR) for MANET has been proposed.By tracing the location information of destination nodes and referring to distance change between nodes to adjust route discovery dynamically,the proposed routing algorithm can avoid flooding in the whole networks.Besides,Distance Update Threshold(DUT) is set up to reach the balance between real-time ability and update overhead of location information of nodes,meanwhile,the detection of relative distance vector can achieve the goal of adjusting forwarding condition.Simulation results reveal that DBLAR performs better than LAR1 in terms of packet successful delivery ratio,average end-to-end delay and routing-load,and the set of DUT and relative distance vector has a significant impact on this algorithm.
基金supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF2013R1A1A1004593, 2013R1A1A1A05012348)
文摘A novel technique called the bitmap lattice index(BLI) is proposed, which combines the advantages of a wireless broadcasting environment with a road network. Existing road networks are based on the on-demand method: a server's workload increases as the query request increases when a server sends a client information. To solve this problem, we propose the BLI. The BLI denotes an object and a node as 0 and 1 in the Hilbert curve(HC) map. The BLI can identify the position of a node and an object through bit information; it can also reduce the broadcasting frequency of a server by reducing the size of the index, thereby decreasing the access latency and query processing times. Moreover, the BLI is highly effective for data filtering, as it can identify the positions of both an object and a node. In a road network, if filtering is done via the Euclidean distance, it may result in an error. To prevent this, we add another validation procedure. The experiment is conducted by applying the BLI to kNN query, and the technique is assessed by a performance evaluation experiment.
文摘Road geometric design data are a vital input for diverse transportation studies. This information is usually obtained from the road design project. However, these are not always available and the as-built course of the road may diverge considerably from its projected one, rendering subsequent studies inaccurate or impossible. Moreover, the systematic acquisition of this data for the entire road network of a country or even a state represents a very challenging and laborious task. This study＇s goal was the extraction of geometric design data for the paved segments of the Brazilian federal highway network, containing more than 47,000 km of highways. It presents the details of the method＇s adoption process, the particularities of its application to the dataset and the obtained geometric design information. Additionally, it provides a first overview of the Brazilian federal highway network composition （curves and tangents） and geometry.
基金Supported by the National Natural Science Foundation of China(No.61379057,61073186,61309001,61379110,61103202)Doctoral Fund of Ministry of Education of China(No.20120162130008)the National Basic Research Program of China(973 Program)(No.2014CB046305)
文摘Opportunistic networks are random networks and do not communicate with each other among respective communication areas.This situation leads to great difficulty in message transfer.This paper proposes a reducing energy consumption optimal selection of path transmission(OSPT) routing algorithm in opportunistic networks.This algorithm designs a dynamic random network topology,creates a dynamic link,and realizes an optimized selected path.This algorithm solves a problem that nodes are unable to deliver messages for a long time in opportunistic networks.According to the simulation experiment,OSPT improves deliver ratio,and reduces energy consumption,cache time and transmission delay compared with the Epidemic Algorithm and Spray and Wait Algorithm in opportunistic networks.
文摘The paper design mobile information collection system based on lnternet of Things, implemented access gateway by smart mobile devices through a variety of ways, such as Wi-Fi and access the underlying perceptual information based on ZigBee wireless sensor networks. On the one hand, For information sensitivity of the sensor network, we design the mobile terminal through the gateway access authentication protocol, and effective solute the authentication and infbnnation between mobile devices and gateways, gateway and sensor network nodes obtain permission problem; on the other hand, according to the practical application of mobile information collection characteristics, the paper proposed information collection strategy based on historical data movement path to solve the problem for too long the device connection is established when the mobile smart devices collecting information along fixed lines, increasing the actual data transmission time and improve the efficiency of information transmission.
文摘Internal control is a hot topic at present academics and for practitioners to explore. Especially under the background of China＇ s rapid integration into the global economy, the rapid establishment and improvement of the context of the modem enterprise system, the issue is of utmost importance. The internal accounting control system is the core part of internal control, which determines the extent of establishing the entire sound internal control system, With the progress of the time, the rapid development and wide application of Internet technology has changed the survival environment and management philosophy for business. The development of network technology achieves the online office, mobile office and decentralized offices, etc. Accounting entity is no longer subject to space limitations of traditional methods, thus a large number of accounting information is transmitted tbaough the network communication lines, so that accounting activities can be extended to every node in the world, which achieves the purpose of remote processing. Under the network environment, sources of information are of diversity and multi-channel. A large number of accounting information transmitted from the network communication lines is likely to be illegally intercepted, stolen and tampered by molecules or people with ulterior motives.
