In disaster situations, people need to evacuate from dangerous areas to safe ones. In particular, they must formulate an evacuation plan for themselves when they cannot obtain support. Communicating with other evacuee...In disaster situations, people need to evacuate from dangerous areas to safe ones. In particular, they must formulate an evacuation plan for themselves when they cannot obtain support. Communicating with other evacuees to obtain information is useful in formulating an evacuation plan, and some studies have used a mobile ad hoc network (MANET) for this purpose, because such a network can be constructed using only wireless devices even when a fatal situation arises. However, we cannot treat a MANET in the same manner as other networks (such as a carrier network or Wi-Fi), and MANETs have several shortcomings in regard to information exchange. It is necessary to investigate the effects of these limitations on creating evacuation support systems on a MANET. We evaluated whether the limited information exchange available using a MANET is sufficient to create evacuation support systems through the use of a multi-agent evacuation simulator. As a result, our simulator showed that limited communication in which people communicate only with neighbors provides substantial efficiency for evacuation. People can continue to evacuate effectively even if they cannot obtain all of the desired information owing to MANET limitations.展开更多
The necessary background as well as the details of simulation was presented to simulate and evaluate the performance of the ad hoc on-demand distance vector routing protocol in mobile ad hoc network with the help of t...The necessary background as well as the details of simulation was presented to simulate and evaluate the performance of the ad hoc on-demand distance vector routing protocol in mobile ad hoc network with the help of the network simulator NS2 using the common transmission range to deliver the data packets at the destination node. The number of participating nodes played an important role to predict the conditions for the best performance of the protocol with respect to throughput, delay, packet delivery ratio, drop packets, consumed and residual energy of the network. Further, the efforts can be put to control the transmission range dynamically and overheads for reducing the energy consumption in the network and improving its lifetime of the nodes and the lifespan of the network.展开更多
The use of mobile nodes to improve network system performance has drawn considerable attention recently The movement-assisted model considers mobility as a desirable feature, where routing is based on the store-carry-...The use of mobile nodes to improve network system performance has drawn considerable attention recently The movement-assisted model considers mobility as a desirable feature, where routing is based on the store-carry-forward paradigm with random or controlled movement of resource rich mobile nodes. The application of such a model has been used in several emerging networks, including mobile ad hoc networks （MANETs）, wireless sensor networks （WSNs）, and delay tolerant networks （DTNs）. It is well known that mobility increases the capacity of MANETs by reducing the number of relays for routing, prolonging the lifespan of WSNs by using mobile nodes in place of bottleneck static sensors, and ensuring network connectivity in DTNs using mobile nodes to connect different parts of a disconnected network. Trajectory planning and the coordination of mobile nodes are two important design issues aiming to optimize or balance several measures, including delay, average number of relays, and moving distance. In this paper, we propose a new controlled mobility model with an expected polylogarithmic number of relays to achieve a good balance among several contradictory goals, including delay, the number of relays, and moving distance. The model is based on the small-world model where each static node has ＂short＂ link connections to its nearest neighbors and ＂long＂ link connections to other nodes following a certain probability distribution. Short links are regular wireless connections whereas long links are implemented using mobile nodes. Various issues are considered, including trade-offs between delay and average number of relays, selection of the number of mobile nodes, and selection of the number of long links. The effectiveness of the proposed model is evaluated analytically as well as through simulation.展开更多
文摘In disaster situations, people need to evacuate from dangerous areas to safe ones. In particular, they must formulate an evacuation plan for themselves when they cannot obtain support. Communicating with other evacuees to obtain information is useful in formulating an evacuation plan, and some studies have used a mobile ad hoc network (MANET) for this purpose, because such a network can be constructed using only wireless devices even when a fatal situation arises. However, we cannot treat a MANET in the same manner as other networks (such as a carrier network or Wi-Fi), and MANETs have several shortcomings in regard to information exchange. It is necessary to investigate the effects of these limitations on creating evacuation support systems on a MANET. We evaluated whether the limited information exchange available using a MANET is sufficient to create evacuation support systems through the use of a multi-agent evacuation simulator. As a result, our simulator showed that limited communication in which people communicate only with neighbors provides substantial efficiency for evacuation. People can continue to evacuate effectively even if they cannot obtain all of the desired information owing to MANET limitations.
文摘The necessary background as well as the details of simulation was presented to simulate and evaluate the performance of the ad hoc on-demand distance vector routing protocol in mobile ad hoc network with the help of the network simulator NS2 using the common transmission range to deliver the data packets at the destination node. The number of participating nodes played an important role to predict the conditions for the best performance of the protocol with respect to throughput, delay, packet delivery ratio, drop packets, consumed and residual energy of the network. Further, the efforts can be put to control the transmission range dynamically and overheads for reducing the energy consumption in the network and improving its lifetime of the nodes and the lifespan of the network.
基金NSF of USA under Grant Nos.CCR 0329741,CNS 0422762,CNS 0434533,CNS 0531410,and CNS 0626240.
文摘The use of mobile nodes to improve network system performance has drawn considerable attention recently The movement-assisted model considers mobility as a desirable feature, where routing is based on the store-carry-forward paradigm with random or controlled movement of resource rich mobile nodes. The application of such a model has been used in several emerging networks, including mobile ad hoc networks （MANETs）, wireless sensor networks （WSNs）, and delay tolerant networks （DTNs）. It is well known that mobility increases the capacity of MANETs by reducing the number of relays for routing, prolonging the lifespan of WSNs by using mobile nodes in place of bottleneck static sensors, and ensuring network connectivity in DTNs using mobile nodes to connect different parts of a disconnected network. Trajectory planning and the coordination of mobile nodes are two important design issues aiming to optimize or balance several measures, including delay, average number of relays, and moving distance. In this paper, we propose a new controlled mobility model with an expected polylogarithmic number of relays to achieve a good balance among several contradictory goals, including delay, the number of relays, and moving distance. The model is based on the small-world model where each static node has ＂short＂ link connections to its nearest neighbors and ＂long＂ link connections to other nodes following a certain probability distribution. Short links are regular wireless connections whereas long links are implemented using mobile nodes. Various issues are considered, including trade-offs between delay and average number of relays, selection of the number of mobile nodes, and selection of the number of long links. The effectiveness of the proposed model is evaluated analytically as well as through simulation.
