Since wireless links in Ad hoc networks are more fragile than those in traditional wireless networks due to route flapping,multi-node cooperation plays an important role in ensuring the quality of service( QoS). Based...Since wireless links in Ad hoc networks are more fragile than those in traditional wireless networks due to route flapping,multi-node cooperation plays an important role in ensuring the quality of service( QoS). Based on the authors' previous work,this paper proposes a receiver-controlled multi-node cooperation routing protocol,known as AODV-RCC. In this protocol,nodes form a cooperation group based on signal power. In a cooperation group,signal power between a partner and a transmitter,as well as signal power between the partner and the receiver,must be larger than the signal power between the transmitter and the receiver. Otherwise,the transmission will not benefit from cooperation. To avoid collision or congestion,each cooperation group only contains one partner. This partner offers both data and ACK cooperative retransmission. Its retransmission time should be shorter than the internal retry time of the transmitter's MAC layer,because it is better for the partner to retransmit firstly,as it offers a more reliable cooperative link. In AODV-RCC,it is the receiver that chooses the partner,because the link between the partner and the receiver is the most important. According to our simulation results,AODV-RCC shortens the end-to-end delay and increases the packet delivery ratio.展开更多
Closed form expressions for the PDF and MGF of the harmonic mean of two independent exponential variates are cited and derived, and then applied to study the performance of cellular multi-node and dual-hop cooperative...Closed form expressions for the PDF and MGF of the harmonic mean of two independent exponential variates are cited and derived, and then applied to study the performance of cellular multi-node and dual-hop cooperative communication systems with non-regenerative relays over flat Rayleigh fading channels. We derive the probability density function (PDF) and asymptotic symbol error rate (SER) expression with MRC scheme. Then we use Matlab to simulate the performance.展开更多
This paper presents the derivation of an analytical model for a multi-queue nodes network router, which is referred to as the multi-queue nodes （mQN） model. In this model, expressions are derived to calculate two pe...This paper presents the derivation of an analytical model for a multi-queue nodes network router, which is referred to as the multi-queue nodes （mQN） model. In this model, expressions are derived to calculate two performance metrics, namely, the queue node and system utilization factors. In order to demonstrate the flexibility and effectiveness of the mQN model in analyzing the performance of an mQN network router, two scenarios are performed. These scenarios investigated the variation of queue nodes and system utilization factors against queue nodes dropping probability for various system sizes and packets arrival routing probabilities. The performed scenarios demonstrated that the mQN analytical model is more flexible and effective when compared with experimental tests and computer simulations in assessing the performance of an mQN network router.展开更多
In Wireless Sensor Network (WSNs), sensor nodes collect data and send them to a Base Station (BS) for further processing. One of the most issues in WSNs that researchers have proposed a hundred of technique to solve i...In Wireless Sensor Network (WSNs), sensor nodes collect data and send them to a Base Station (BS) for further processing. One of the most issues in WSNs that researchers have proposed a hundred of technique to solve its impact is the energy constraint since sensor nodes have small battery, small memory and less data processing with low computational capabilities. However, many researches efforts have focused on how to prolong the battery lifetime of sensor nodes by proposing different routing, MAC, localization, data aggregation, topology construction techniques. In this paper, we will focus on routing techniques which aim to prolonging the network lifetime. Hence, we propose an Energy-Efficient Routing technique in WSNs based on Stationary and Mobile nodes (EERSM). Sensing filed is divided into intersected circles which contain Mobile Nodes (MN). The proposed data aggregation technique via the circular topology will eliminate the redundant data to be sent to the Base Station (BS). MN in each circle will rout packets for their source nodes, and move to the intersected area where another MN is waiting (sleep mode) to receive the transmitted packet, and then the packet will be delivered to the next intersected area until the packet is arrived to the BS. Our proposed EERSM technique is simulated using MATLAB and compared with conventional multi-hop techniques under different network models and scenarios. In the simulation, we will show how the proposed EERSM technique overcomes many routing protocols in terms of the number of hops counted when sending packets from a source node to the destination (i.e. BS), the average residual energy, number of sent packets to the BS, and the number of a live sensor nodes verse the simulation rounds.展开更多
Nodes cooperation is a significant prerequisite for the realization of the relaying Ad Hoc.While with the development of multi-hop cellular networks, how to stimulate intermediate nodes to do the packet-forwarding des...Nodes cooperation is a significant prerequisite for the realization of the relaying Ad Hoc.While with the development of multi-hop cellular networks, how to stimulate intermediate nodes to do the packet-forwarding deserves more concerning.At present research,the incentive schemes in pure Ad Hoc and multi-hop cellular networks are analyzed and compared to classify the strengths and drawbacks of each scheme.We explain in particular what the key issues are to implement incentive schemes for cooperation. Finally,an incentive scheme based on integration of reputation and charging systems is proposed not only to block the existence of selfish nodes,but to satisfy the rational requirement of nodes.展开更多
为解决篇章级多事件抽取中事件及论元角色间全局语义关联缺失、文档信息利用不足的问题,提出了基于论元关联和图神经网络的篇章级多事件抽取(document-level multi-event extraction based on argument correlation and graph neural ne...为解决篇章级多事件抽取中事件及论元角色间全局语义关联缺失、文档信息利用不足的问题,提出了基于论元关联和图神经网络的篇章级多事件抽取(document-level multi-event extraction based on argument correlation and graph neural network,DEEACG)模型。首先,使用基于变换器的双向编码器表示(bidirectional encoder representations from Transformers,BERT)模块获取实体,并引入实体共事件性预测任务,增强实体间的语义关联。接着,引入可学习的事件代理节点,构建包含实体、上下文和代理节点的异构图,通过特征线性调制图神经网络(graph neural network with feature-wise linear modulation,GNN-FiLM)与多头自注意力机制,实现多事件间的全局交互与语义融合。然后,通过多层感知机进行事件类型检测。最后,构建双投影空间建模论元关联,采用Bron-Kerbosch算法提取图中极大团作为候选论元组合,并结合多头注意力实现论元角色分类。结果表明,DEEACG模型在中文金融公告(Chinese financial announcements,ChFinAnn)数据集的多事件抽取任务中性能明显提升,与关系增强文档级事件抽取(relation-enabled document-level event extraction,ReDEE)模型相比,F1均值提升了2.1个百分点。该研究证实DEEACG模型能有效捕捉多事件间语义关联,适用于篇章级多事件抽取任务。展开更多
基金Sponsored by the Natural Scientific Research Innovation Foundation in Harbin Institute of Technology(Grant No.HIT.NSRIF.2013029)the National Science and Technology Major Project(Grant No.2012ZX03004003)+1 种基金the National Basic Research Development Program of China(973 Program)(Grant No.2013CB329003)the National Natural Science Foundation of China(Grant No.61201148 and No.61101123)
文摘Since wireless links in Ad hoc networks are more fragile than those in traditional wireless networks due to route flapping,multi-node cooperation plays an important role in ensuring the quality of service( QoS). Based on the authors' previous work,this paper proposes a receiver-controlled multi-node cooperation routing protocol,known as AODV-RCC. In this protocol,nodes form a cooperation group based on signal power. In a cooperation group,signal power between a partner and a transmitter,as well as signal power between the partner and the receiver,must be larger than the signal power between the transmitter and the receiver. Otherwise,the transmission will not benefit from cooperation. To avoid collision or congestion,each cooperation group only contains one partner. This partner offers both data and ACK cooperative retransmission. Its retransmission time should be shorter than the internal retry time of the transmitter's MAC layer,because it is better for the partner to retransmit firstly,as it offers a more reliable cooperative link. In AODV-RCC,it is the receiver that chooses the partner,because the link between the partner and the receiver is the most important. According to our simulation results,AODV-RCC shortens the end-to-end delay and increases the packet delivery ratio.
文摘Closed form expressions for the PDF and MGF of the harmonic mean of two independent exponential variates are cited and derived, and then applied to study the performance of cellular multi-node and dual-hop cooperative communication systems with non-regenerative relays over flat Rayleigh fading channels. We derive the probability density function (PDF) and asymptotic symbol error rate (SER) expression with MRC scheme. Then we use Matlab to simulate the performance.
文摘This paper presents the derivation of an analytical model for a multi-queue nodes network router, which is referred to as the multi-queue nodes （mQN） model. In this model, expressions are derived to calculate two performance metrics, namely, the queue node and system utilization factors. In order to demonstrate the flexibility and effectiveness of the mQN model in analyzing the performance of an mQN network router, two scenarios are performed. These scenarios investigated the variation of queue nodes and system utilization factors against queue nodes dropping probability for various system sizes and packets arrival routing probabilities. The performed scenarios demonstrated that the mQN analytical model is more flexible and effective when compared with experimental tests and computer simulations in assessing the performance of an mQN network router.
文摘In Wireless Sensor Network (WSNs), sensor nodes collect data and send them to a Base Station (BS) for further processing. One of the most issues in WSNs that researchers have proposed a hundred of technique to solve its impact is the energy constraint since sensor nodes have small battery, small memory and less data processing with low computational capabilities. However, many researches efforts have focused on how to prolong the battery lifetime of sensor nodes by proposing different routing, MAC, localization, data aggregation, topology construction techniques. In this paper, we will focus on routing techniques which aim to prolonging the network lifetime. Hence, we propose an Energy-Efficient Routing technique in WSNs based on Stationary and Mobile nodes (EERSM). Sensing filed is divided into intersected circles which contain Mobile Nodes (MN). The proposed data aggregation technique via the circular topology will eliminate the redundant data to be sent to the Base Station (BS). MN in each circle will rout packets for their source nodes, and move to the intersected area where another MN is waiting (sleep mode) to receive the transmitted packet, and then the packet will be delivered to the next intersected area until the packet is arrived to the BS. Our proposed EERSM technique is simulated using MATLAB and compared with conventional multi-hop techniques under different network models and scenarios. In the simulation, we will show how the proposed EERSM technique overcomes many routing protocols in terms of the number of hops counted when sending packets from a source node to the destination (i.e. BS), the average residual energy, number of sent packets to the BS, and the number of a live sensor nodes verse the simulation rounds.
基金supported by National "863" High Technology Research and Development Program Foundation(No.2006AA01Z208)Six Talented Eminence Foundation of Jiangsu Province+1 种基金Natural Science Foundation of Jiangsu Province(No. BK2004149)Green-Blue Academic Talented Project Foundation of Jiangsu Province
文摘Nodes cooperation is a significant prerequisite for the realization of the relaying Ad Hoc.While with the development of multi-hop cellular networks, how to stimulate intermediate nodes to do the packet-forwarding deserves more concerning.At present research,the incentive schemes in pure Ad Hoc and multi-hop cellular networks are analyzed and compared to classify the strengths and drawbacks of each scheme.We explain in particular what the key issues are to implement incentive schemes for cooperation. Finally,an incentive scheme based on integration of reputation and charging systems is proposed not only to block the existence of selfish nodes,but to satisfy the rational requirement of nodes.
文摘为解决篇章级多事件抽取中事件及论元角色间全局语义关联缺失、文档信息利用不足的问题,提出了基于论元关联和图神经网络的篇章级多事件抽取(document-level multi-event extraction based on argument correlation and graph neural network,DEEACG)模型。首先,使用基于变换器的双向编码器表示(bidirectional encoder representations from Transformers,BERT)模块获取实体,并引入实体共事件性预测任务,增强实体间的语义关联。接着,引入可学习的事件代理节点,构建包含实体、上下文和代理节点的异构图,通过特征线性调制图神经网络(graph neural network with feature-wise linear modulation,GNN-FiLM)与多头自注意力机制,实现多事件间的全局交互与语义融合。然后,通过多层感知机进行事件类型检测。最后,构建双投影空间建模论元关联,采用Bron-Kerbosch算法提取图中极大团作为候选论元组合,并结合多头注意力实现论元角色分类。结果表明,DEEACG模型在中文金融公告(Chinese financial announcements,ChFinAnn)数据集的多事件抽取任务中性能明显提升,与关系增强文档级事件抽取(relation-enabled document-level event extraction,ReDEE)模型相比,F1均值提升了2.1个百分点。该研究证实DEEACG模型能有效捕捉多事件间语义关联,适用于篇章级多事件抽取任务。
