期刊文献+
共找到18,335篇文章
< 1 2 250 >
每页显示 20 50 100
The Channel Branches & Network Vessels on the Tianhui Lacquered Meridian Figurine——Taking the Heart-Regulated Channel as an Example 被引量:1
1
作者 ZHOU Qi Lena Springer 《Chinese Medicine and Culture》 2024年第3期222-232,共11页
Along with the surge of unearthed medical literature and cultural relics in recent years,a network of channels in the system of medical conduit vessels(meridians) during the early Western Han dynasty has become much c... Along with the surge of unearthed medical literature and cultural relics in recent years,a network of channels in the system of medical conduit vessels(meridians) during the early Western Han dynasty has become much clearer gradually.In it,the increasing number of channel branches,network vessels and needle insertion holes(acupoints) is an important feature of the development of channel medicine during the Western Han dynasty.This is not only a reflection of the expanding requirements of the theoretical system of the main trunk channels and other vessels,but also an inevitable result of the continuous enrichment and accumulation of clinical experience.This article integrates the information about channel branches,network vessels,inscriptions,dots and further relics on the Tianhui(天回) Lacquered Meridian Figurine to compare the unearthed literature of the channel genre with the transmitted classical literature about acupuncture.The “Heart-Regulated Channel” in Medical Manuscripts on Bamboo Slips from Tianhui(《天回医简》) serves as an example to explain the occurrence,development and changes of the channel branches and network vessels in the early system of medical channels. 展开更多
关键词 Tianhui Lacquered Meridian Figurine(天回髹漆经脉人像) Tianhui Medicine Slips Heart-Regulated Channel(心主之脉) Channel branches network channels
下载PDF
DCFNet:An Effective Dual-Branch Cross-Attention Fusion Network for Medical Image Segmentation
2
作者 Chengzhang Zhu Renmao Zhang +5 位作者 Yalong Xiao Beiji Zou Xian Chai Zhangzheng Yang Rong Hu Xuanchu Duan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期1103-1128,共26页
Automatic segmentation of medical images provides a reliable scientific basis for disease diagnosis and analysis.Notably,most existing methods that combine the strengths of convolutional neural networks(CNNs)and Trans... Automatic segmentation of medical images provides a reliable scientific basis for disease diagnosis and analysis.Notably,most existing methods that combine the strengths of convolutional neural networks(CNNs)and Transformers have made significant progress.However,there are some limitations in the current integration of CNN and Transformer technology in two key aspects.Firstly,most methods either overlook or fail to fully incorporate the complementary nature between local and global features.Secondly,the significance of integrating the multiscale encoder features from the dual-branch network to enhance the decoding features is often disregarded in methods that combine CNN and Transformer.To address this issue,we present a groundbreaking dual-branch cross-attention fusion network(DCFNet),which efficiently combines the power of Swin Transformer and CNN to generate complementary global and local features.We then designed the Feature Cross-Fusion(FCF)module to efficiently fuse local and global features.In the FCF,the utilization of the Channel-wise Cross-fusion Transformer(CCT)serves the purpose of aggregatingmulti-scale features,and the Feature FusionModule(FFM)is employed to effectively aggregate dual-branch prominent feature regions from the spatial perspective.Furthermore,within the decoding phase of the dual-branch network,our proposed Channel Attention Block(CAB)aims to emphasize the significance of the channel features between the up-sampled features and the features generated by the FCFmodule to enhance the details of the decoding.Experimental results demonstrate that DCFNet exhibits enhanced accuracy in segmentation performance.Compared to other state-of-the-art(SOTA)methods,our segmentation framework exhibits a superior level of competitiveness.DCFNet’s accurate segmentation of medical images can greatly assist medical professionals in making crucial diagnoses of lesion areas in advance. 展开更多
关键词 Convolutional neural networks Swin Transformer dual branch medical image segmentation feature cross fusion
下载PDF
Multi-Head Attention Spatial-Temporal Graph Neural Networks for Traffic Forecasting
3
作者 Xiuwei Hu Enlong Yu Xiaoyu Zhao 《Journal of Computer and Communications》 2024年第3期52-67,共16页
Accurate traffic prediction is crucial for an intelligent traffic system (ITS). However, the excessive non-linearity and complexity of the spatial-temporal correlation in traffic flow severely limit the prediction acc... Accurate traffic prediction is crucial for an intelligent traffic system (ITS). However, the excessive non-linearity and complexity of the spatial-temporal correlation in traffic flow severely limit the prediction accuracy of most existing models, which simply stack temporal and spatial modules and fail to capture spatial-temporal features effectively. To improve the prediction accuracy, a multi-head attention spatial-temporal graph neural network (MSTNet) is proposed in this paper. First, the traffic data is decomposed into unique time spans that conform to positive rules, and valuable traffic node attributes are mined through an adaptive graph structure. Second, time and spatial features are captured using a multi-head attention spatial-temporal module. Finally, a multi-step prediction module is used to achieve future traffic condition prediction. Numerical experiments were conducted on an open-source dataset, and the results demonstrate that MSTNet performs well in spatial-temporal feature extraction and achieves more positive forecasting results than the baseline methods. 展开更多
关键词 Traffic Prediction Intelligent Traffic System multi-Head Attention Graph Neural networks
下载PDF
A Lightweight Convolutional Neural Network with Hierarchical Multi-Scale Feature Fusion for Image Classification
4
作者 Adama Dembele Ronald Waweru Mwangi Ananda Omutokoh Kube 《Journal of Computer and Communications》 2024年第2期173-200,共28页
Convolutional neural networks (CNNs) are widely used in image classification tasks, but their increasing model size and computation make them challenging to implement on embedded systems with constrained hardware reso... Convolutional neural networks (CNNs) are widely used in image classification tasks, but their increasing model size and computation make them challenging to implement on embedded systems with constrained hardware resources. To address this issue, the MobileNetV1 network was developed, which employs depthwise convolution to reduce network complexity. MobileNetV1 employs a stride of 2 in several convolutional layers to decrease the spatial resolution of feature maps, thereby lowering computational costs. However, this stride setting can lead to a loss of spatial information, particularly affecting the detection and representation of smaller objects or finer details in images. To maintain the trade-off between complexity and model performance, a lightweight convolutional neural network with hierarchical multi-scale feature fusion based on the MobileNetV1 network is proposed. The network consists of two main subnetworks. The first subnetwork uses a depthwise dilated separable convolution (DDSC) layer to learn imaging features with fewer parameters, which results in a lightweight and computationally inexpensive network. Furthermore, depthwise dilated convolution in DDSC layer effectively expands the field of view of filters, allowing them to incorporate a larger context. The second subnetwork is a hierarchical multi-scale feature fusion (HMFF) module that uses parallel multi-resolution branches architecture to process the input feature map in order to extract the multi-scale feature information of the input image. Experimental results on the CIFAR-10, Malaria, and KvasirV1 datasets demonstrate that the proposed method is efficient, reducing the network parameters and computational cost by 65.02% and 39.78%, respectively, while maintaining the network performance compared to the MobileNetV1 baseline. 展开更多
关键词 MobileNet Image Classification Lightweight Convolutional Neural network Depthwise Dilated Separable Convolution Hierarchical multi-Scale Feature Fusion
下载PDF
Multi-Agent Deep Reinforcement Learning for Cross-Layer Scheduling in Mobile Ad-Hoc Networks
5
作者 Xinxing Zheng Yu Zhao +1 位作者 Joohyun Lee Wei Chen 《China Communications》 SCIE CSCD 2023年第8期78-88,共11页
Due to the fading characteristics of wireless channels and the burstiness of data traffic,how to deal with congestion in Ad-hoc networks with effective algorithms is still open and challenging.In this paper,we focus o... Due to the fading characteristics of wireless channels and the burstiness of data traffic,how to deal with congestion in Ad-hoc networks with effective algorithms is still open and challenging.In this paper,we focus on enabling congestion control to minimize network transmission delays through flexible power control.To effectively solve the congestion problem,we propose a distributed cross-layer scheduling algorithm,which is empowered by graph-based multi-agent deep reinforcement learning.The transmit power is adaptively adjusted in real-time by our algorithm based only on local information(i.e.,channel state information and queue length)and local communication(i.e.,information exchanged with neighbors).Moreover,the training complexity of the algorithm is low due to the regional cooperation based on the graph attention network.In the evaluation,we show that our algorithm can reduce the transmission delay of data flow under severe signal interference and drastically changing channel states,and demonstrate the adaptability and stability in different topologies.The method is general and can be extended to various types of topologies. 展开更多
关键词 Ad-hoc network cross-layer scheduling multi agent deep reinforcement learning interference elimination power control queue scheduling actorcritic methods markov decision process
下载PDF
Grid Side Distributed Energy Storage Cloud Group End Region Hierarchical Time-Sharing Configuration Algorithm Based onMulti-Scale and Multi Feature Convolution Neural Network
6
作者 Wen Long Bin Zhu +3 位作者 Huaizheng Li Yan Zhu Zhiqiang Chen Gang Cheng 《Energy Engineering》 EI 2023年第5期1253-1269,共17页
There is instability in the distributed energy storage cloud group end region on the power grid side.In order to avoid large-scale fluctuating charging and discharging in the power grid environment and make the capaci... There is instability in the distributed energy storage cloud group end region on the power grid side.In order to avoid large-scale fluctuating charging and discharging in the power grid environment and make the capacitor components showa continuous and stable charging and discharging state,a hierarchical time-sharing configuration algorithm of distributed energy storage cloud group end region on the power grid side based on multi-scale and multi feature convolution neural network is proposed.Firstly,a voltage stability analysis model based onmulti-scale and multi feature convolution neural network is constructed,and the multi-scale and multi feature convolution neural network is optimized based on Self-OrganizingMaps(SOM)algorithm to analyze the voltage stability of the cloud group end region of distributed energy storage on the grid side under the framework of credibility.According to the optimal scheduling objectives and network size,the distributed robust optimal configuration control model is solved under the framework of coordinated optimal scheduling at multiple time scales;Finally,the time series characteristics of regional power grid load and distributed generation are analyzed.According to the regional hierarchical time-sharing configuration model of“cloud”,“group”and“end”layer,the grid side distributed energy storage cloud group end regional hierarchical time-sharing configuration algorithm is realized.The experimental results show that after applying this algorithm,the best grid side distributed energy storage configuration scheme can be determined,and the stability of grid side distributed energy storage cloud group end region layered timesharing configuration can be improved. 展开更多
关键词 multiscale and multi feature convolution neural network distributed energy storage at grid side cloud group end region layered time-sharing configuration algorithm
下载PDF
基于长短时记忆神经网络的Multi-GNSS卫星钟差建模预报 被引量:1
7
作者 蒋春华 朱美珍 +1 位作者 薛慧杰 刘广盛 《大地测量与地球动力学》 CSCD 北大核心 2024年第3期257-262,共6页
针对卫星钟差预报中二次多项式模型存在易受噪声干扰、预报精度不高的问题,构建一种基于长短时记忆神经网络的multi-GNSS卫星钟差预报模型,并分析不同卫星系统、不同钟类型基于不同建模方案的模型精度。为验证该模型的有效性和可行性,利... 针对卫星钟差预报中二次多项式模型存在易受噪声干扰、预报精度不高的问题,构建一种基于长短时记忆神经网络的multi-GNSS卫星钟差预报模型,并分析不同卫星系统、不同钟类型基于不同建模方案的模型精度。为验证该模型的有效性和可行性,利用LSTM模型、QP模型、QP-LSTM模型分别基于12 h和24 h钟差序列进行建模,预报1 h、3 h、6 h、12 h钟差。结果表明,LSTM模型建模24 h、预报1 h精度最高。multi-GNSS卫星钟差LSTM预报模型中Galileo系统精度最高,其次为BDS-2系统和GPS系统,GLONASS系统精度最低,精度分别为0.018 ns、0.069 ns、0.133 ns、0.242 ns。不同原子钟预报精度不同,氢原子钟预报精度优于铷原子钟、铯原子钟。LSTM神经网络模型预报精度相较于QP-LSTM模型提升27%,相较于QP模型提升36%。 展开更多
关键词 长短时记忆神经网络(LSTM) 二次多项式模型 QP-LSTM模型 multi-GNSS卫星钟差预报
下载PDF
Multi-Agent模式下的城市暴雨内涝应急决策方法研究
8
作者 王莉 杨若昕 +2 位作者 曹景稳 景紫嫣 李佳欢 《中国安全生产科学技术》 CAS CSCD 北大核心 2024年第4期199-206,共8页
为厘清应对暴雨内涝灾害动态决策过程中决策主体、决策、决策方案等决策要素间的不确定关系,提出1种多主体(Multi-Agent)和贝叶斯决策网络(BDN)相结合的应急决策方法。首先分阶段构建“主体-任务”可视化网络,分析暴雨内涝灾害各应急阶... 为厘清应对暴雨内涝灾害动态决策过程中决策主体、决策、决策方案等决策要素间的不确定关系,提出1种多主体(Multi-Agent)和贝叶斯决策网络(BDN)相结合的应急决策方法。首先分阶段构建“主体-任务”可视化网络,分析暴雨内涝灾害各应急阶段的主要任务和参与的决策主体;在考虑到决策要素间的动态不确定性可能造成决策风险的前提下,运用Multi-Agent和BDN方法探究各决策要素间的影响关系,以便进行方案集优选。研究结果表明:该方法具有实用性和现实意义,研究结果可为城市暴雨内涝灾害的应急决策提供理论参考。 展开更多
关键词 城市暴雨内涝 贝叶斯决策网络 多主体应急决策 不确定关系 “主体-任务”互动网络
下载PDF
Mean Field Annealing Neural Network for the Optimal DS/CDMA Multiuser Detector *
9
作者 仲文 程时昕 《Journal of Southeast University(English Edition)》 EI CAS 1998年第1期17-22,共6页
In this paper, an optimal multi user detector in DS/CDMA communication systems based on the mean field annealing (MFA) neural network is proposed. It is shown that the NP complete problem of minimizing the objective... In this paper, an optimal multi user detector in DS/CDMA communication systems based on the mean field annealing (MFA) neural network is proposed. It is shown that the NP complete problem of minimizing the objective function of the optimal multi user detector can be translated into minimizing an MFA network energy function. Numerical results show that the proposed detector offers significant performance gain relative to the conventional detector and decorrelating detector while it can be implemented easily in analog hardware. 展开更多
关键词 multi user detection near far problem mean field annealing neural network
下载PDF
Real-time multi-step prediction control for BP network with delay 被引量:8
10
作者 张吉礼 欧进萍 于达仁 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2000年第2期82-86,共5页
Real time multi step prediction of BP network based on dynamical compensation of system characteristics is suggested by introducing the first and second derivatives of the system and network outputs into the network i... Real time multi step prediction of BP network based on dynamical compensation of system characteristics is suggested by introducing the first and second derivatives of the system and network outputs into the network input layer, and real time multi step prediction control is proposed for the BP network with delay on the basis of the results of real time multi step prediction, to achieve the simulation of real time fuzzy control of the delayed time system. 展开更多
关键词 DELAYED time system multi STEP prediction BP network COMPENSATION of DYNAMICAL characteristics fuzzy control simulation
下载PDF
The Optimization Study about Fault Self-Healing Restoration of Power Distribution Network Based on Multi-Agent Technology 被引量:3
11
作者 Fuquan Huang Zijun Liu +2 位作者 Tinghuang Wang Haitai Zhang Tony Yip 《Computers, Materials & Continua》 SCIE EI 2020年第10期865-878,共14页
In order to quickly and accurately locate the fault location of the distribution network and increase the stability of the distribution network,a fault recovery method based on multi-objective optimization algorithm i... In order to quickly and accurately locate the fault location of the distribution network and increase the stability of the distribution network,a fault recovery method based on multi-objective optimization algorithm is proposed.The optimization of the power distribution network fault system based on multiagent technology realizes fast recovery of multi-objective fault,solve the problem of network learning and parameter adjustment in the later stage of particle swarm optimization algorithm falling into the local extreme value dilemma,and realize the multi-dimensional nonlinear optimization of the main grid and the auxiliary grid.The system proposed in this study takes power distribution network as the goal,applies fuzzy probability algorithm,simplifies the calculation process,avoids local extreme value,and finally realizes the energy balance between each power grid.Simulation results show that the Multi-Agent Technology enjoys priority in restoring important load,shortening the recovery time of power grid balance,and reducing the overall line loss rate of power grid.Therefore,the power grid fault self-healing system can improve the safety and stability of the important power grid,and reduce the economic loss rate of the whole power grid. 展开更多
关键词 multi agent TECHNOLOGY power distribution network fault self-healing
下载PDF
Using multi-class queuing network to solve performance models of e-business sites 被引量:1
12
作者 郑小盈 陈德人 《Journal of Zhejiang University Science》 EI CSCD 2004年第1期31-39,共9页
Due to e-business' s variety of customers with different navigational patterns and demands, multiclass queuing network is a natural performance model for it. The open multi-class queuing network(QN) models are bas... Due to e-business' s variety of customers with different navigational patterns and demands, multiclass queuing network is a natural performance model for it. The open multi-class queuing network(QN) models are based on the assumption that no service center is saturated as a result of the combined loads of all the classes. Several formulas are used to calculate performance measures, including throughput, residence time, queue length, response time and the average number of requests. The solution technique of closed multi-class QN models is an approximate mean value analysis algorithm (MVA) based on three key equations, because the exact algorithm needs huge time and space requirement. As mixed multi-class QN models, include some open and some closed classes, the open classes should be eliminated to create a closed multi-class QN so that the closed model algorithm can be applied. Some corresponding examples are given to show how to apply the algorithms mentioned in this article. These examples indicate that multi-class QN is a reasonably accurate model of e-business and can be solved efficiently. 展开更多
关键词 Queuing network (QN) multi class Performance E business
下载PDF
Multi-Objective Optimization and Analysis Model of Sintering Process Based on BP Neural Network 被引量:18
13
作者 ZHANG Jun-hong XIE An-guo SHEN Feng-man 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2007年第2期1-5,共5页
A multi-objective optimization and analysis model of the sintering process based on BP neural network is presented. Genetic algorithms are combined to simplify the BP neural network, which can reduce the learning time... A multi-objective optimization and analysis model of the sintering process based on BP neural network is presented. Genetic algorithms are combined to simplify the BP neural network, which can reduce the learning time and increase the forecasting accuracy of the network model. This model has been experimented in the sintering process, and the production cost, the energy consumption, the quality (revolving intensity), and the output are considered at the same time. Moreover, the relation between some factors and the multi-objectives has been analyzed, and the results are consistent with the process. Different objectives are emphasized at different practical periods, and this can provide a theoretical basis for the manager. 展开更多
关键词 BP neural network multi-OBJECTIVE OPTIMIZATION SINTER
下载PDF
Reliable Braided Multipath Routing with Network Coding for Underwater Sensor Networks 被引量:5
14
作者 杨余旺 古力 +3 位作者 鞠玉涛 郑亚 孙亚民 杨静宇 《China Ocean Engineering》 SCIE EI 2010年第3期565-574,共10页
Owing to the long propagation delay and high error rate of acoustic channels, it is very challenging to provide reliable data transfer for underwater sensor networks. Moreover, network coding is proved to be an effect... Owing to the long propagation delay and high error rate of acoustic channels, it is very challenging to provide reliable data transfer for underwater sensor networks. Moreover, network coding is proved to be an effective coding technique for throughput and robustness of networks. In this paper, we propose a Reliable Braided Multipath Routing with Network Coding for underwater sensor networks (RBMR-NC). Disjoint multi-path algorithm is used to build independent actual paths, as called main paths. Some braided paths on each main path are built according to the braided multi-path algorithm, which are called logic paths. When a data packet is transmitted by these nodes, the nodes can employ network coding to encode packets coming from the same group in order to further reduce relativity among these packets, and enhance the probability of successful decoding at the sink node. Braided multi-path can make the main paths to be multiplexed to reduce the probability of long paths. This paper mainly employs successful delivery rate to evaluate RBMR-NC model with theoretical analysis and simulation methods. The results indicate that the proposed RBMR-NC protocol is valuable to enhance network reliability and to reduce system redundancy. 展开更多
关键词 network coding multi-path routing underwater sensor networks network reliability
下载PDF
Laplacian energy maximizationfor multi-layer air transportation networks 被引量:2
15
作者 Zheng Yue Li Wenquan +1 位作者 Qiu Feng Cao Xi 《Journal of Southeast University(English Edition)》 EI CAS 2017年第3期341-347,共7页
To increase airspace capacity, alleviate flight delay,and improve network robustness, an optimization method of multi-layer air transportation networks is put forward based on Laplacian energy maximization. The effect... To increase airspace capacity, alleviate flight delay,and improve network robustness, an optimization method of multi-layer air transportation networks is put forward based on Laplacian energy maximization. The effectiveness of taking Laplacian energy as a measure of network robustness is validated through numerical experiments. The flight routes addition optimization model is proposed with the principle of maximizing Laplacian energy. Three methods including the depth-first search( DFS) algorithm, greedy algorithm and Monte-Carlo tree search( MCTS) algorithm are applied to solve the proposed problem. The trade-off between system performance and computational efficiency is compared through simulation experiments. Finally, a case study on Chinese airport network( CAN) is conducted using the proposed model. Through encapsulating it into multi-layer infrastructure via k-core decomposition algorithm, Laplacian energy maximization for the sub-networks is discussed which can provide a useful tool for the decision-makers to optimize the robustness of the air transportation network on different scales. 展开更多
关键词 air TRANSPORTATION network LAPLACIAN ENERGY ROBUSTNESS multi-LAYER networkS
下载PDF
Multi-Strategy Dynamic Spectrum Access in Cognitive Radio Networks: Modeling, Analysis and Optimization 被引量:9
16
作者 Yi Yang Qinyu Zhang +3 位作者 Ye Wang Takahiro Emoto Masatake Akutagawa Shinsuke Konaka 《China Communications》 SCIE CSCD 2019年第3期103-121,共19页
Dynamic spectrum access(DSA) based on cognitive radios(CR) technique is an effective approach to address the "spectrum scarcity" issue. However, traditional CR-enabled DSA system employs only single DSA stra... Dynamic spectrum access(DSA) based on cognitive radios(CR) technique is an effective approach to address the "spectrum scarcity" issue. However, traditional CR-enabled DSA system employs only single DSA strategy, which might not be suited to the dynamic network environment. In this paper, we propose a multi-strategy DSA(MS-DSA) system, where the primary and the secondary system share spectrum resources with multiple DSA strategies simultaneously. To analyze the performance of the proposed MS-DSA system, we model it as a continuous-time Markov chain(CTMC) and derive the expressions to compute the corresponding performance metrics. Based on this, we define a utility function involving the concerns of effective throughput, interference quantity on primary users, and spectrum leasing cost. Two optimization schemes, named as spectrum allocation and false alarm probability selection, are proposed to maximize the utility function. Finally, numerical simulations are provided to validate our analysis and demonstrate that the performance can be significantly improved caused by virtues of the proposed MS-DSA system. 展开更多
关键词 COGNITIVE RADIO networks dynamic SPECTRUM access multi-strategy performance analysis optimization
下载PDF
A PSO Based Multi-Domain Virtual Network Embedding Approach 被引量:4
17
作者 Yongjing Ni Guoyan Huang +3 位作者 Sheng Wu Chenxi Li Peiying Zhang Haipeng Yao 《China Communications》 SCIE CSCD 2019年第4期105-119,共15页
This paper proposed a multi-domain virtual network embedding algorithm based on multi-controller SDN architecture. The local controller first selects candidate substrate nodes for each virtual node in the domain. Then... This paper proposed a multi-domain virtual network embedding algorithm based on multi-controller SDN architecture. The local controller first selects candidate substrate nodes for each virtual node in the domain. Then the global controller abstracts substrate network topology based on the candidate nodes and boundary nodes of each domain, and applies Particle Swarm Optimization Algorithm on it to divide virtual network requests. Each local controller then embeds the virtual nodes of the divided single-domain virtual network requests in the domain, and cooperates with other local controllers to embed the inter-domain virtual links. Simulation experimental results show that the proposed algorithm has good performance in reducing embedding cost with good stability and scalability. 展开更多
关键词 multi-DOMAIN VIRTUAL network embedding CANDIDATE node particle SWARM optimization algorithm VIRTUAL network REQUEST division
下载PDF
Complex field network-coded cooperation based on multi-user detection in wireless networks 被引量:2
18
作者 Jing Wang Xiangyang Liu +1 位作者 Kaikai Chi Xiangmo Zhao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2013年第2期215-221,共7页
Cooperative communication can achieve spatial diversity gains,and consequently combats signal fading due to multipath propagation in wireless networks powerfully.A novel complex field network-coded cooperation(CFNCC... Cooperative communication can achieve spatial diversity gains,and consequently combats signal fading due to multipath propagation in wireless networks powerfully.A novel complex field network-coded cooperation(CFNCC) scheme based on multi-user detection for the multiple unicast transmission is proposed.Theoretic analysis and simulation results demonstrate that,compared with the conventional cooperation(CC) scheme and network-coded cooperation(NCC) scheme,CFNCC would obtain higher network throughput and consumes less time slots.Moreover,a further investigation is made for the symbol error probability(SEP) performance of CFNCC scheme,and SEPs of CFNCC scheme are compared with those of NCC scheme in various scenarios for different signal to noise ratio(SNR) values. 展开更多
关键词 network coding complex field wireless network cooperative communication multi-user detection
下载PDF
Multi-Path Routing and Resource Allocation in Active Network 被引量:2
19
作者 XUWu-ping YANPu-liu WUMing 《Wuhan University Journal of Natural Sciences》 EI CAS 2005年第2期398-404,共7页
An algorithm of traffic distribution called active multi-path routing (AMR)in active network is proposed. AMR adopts multi-path routing and applies nonlinear optimizeapproximate method to distribute network traffic am... An algorithm of traffic distribution called active multi-path routing (AMR)in active network is proposed. AMR adopts multi-path routing and applies nonlinear optimizeapproximate method to distribute network traffic among multiple paths. It is combined to bandwidthresource allocation and the congestion restraint mechanism to avoid congestion happening and worsen.So network performance can be improved greatly. The frame of AMR includes adaptive trafficallocation model, the conception of supply bandwidth and its' allocation model, the principle ofcongestion restraint and its' model, and the implement of AMR based on multi-agents system in activenetwork. Through simulations, AMR has distinct effects on network performance. The results show AMRisa valid traffic regulation algorithm. 展开更多
关键词 multi-path routing resource allocation congestion control active network multi-agent system
下载PDF
IMPROVED MODE-MATCHING AND NETWORK ANALYSIS OF E-PLANE WAVEGUIDE BRANCH DIRECTIONAL COUPLERS
20
作者 徐善驾 王峰 《Journal of Electronics(China)》 1995年第4期378-383,共6页
The E-plane waveguide branch directional couplers are analyzed by a method which combines the multimode network theory with rigorous mode-matching approach. The electromagnetic field components are expanded by the sup... The E-plane waveguide branch directional couplers are analyzed by a method which combines the multimode network theory with rigorous mode-matching approach. The electromagnetic field components are expanded by the superposition of LSEx modes rather than TE and TM modes in the mode-matching procedure. Meanwhile, the electromagnetic problem is transferred into the network problem through the mode-matching treatment. It is shown that the present method has the advantages of simplicity and less computation without affecting the accuracy of the calculation. 展开更多
关键词 E-PLANE WAVEGUIDE branch Directional COUPLER MODE-MATCHING multiMODE network THEORY
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部