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Enhancing the stability of Ni Fe-layered double hydroxide nanosheet array for alkaline seawater oxidation by Ce doping 被引量:1
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作者 Yongchao Yao Shengjun Sun +14 位作者 Hui Zhang Zixiao Li Chaoxin Yang Zhengwei Cai Xun He Kai Dong Yonglan Luo Yan Wang Yuchun Ren Qian Liu Dongdong Zheng Weihua Zhuang Bo Tang Xuping Sun Wenchuang(Walter)Hu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期306-312,共7页
Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability cau... Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability caused by detrimental chlorine chemistry.Herein,we present our recent discovery that the incorporation of Ce into Ni Fe layered double hydroxide nanosheet array on Ni foam(Ce-Ni Fe LDH/NF)emerges as a robust electrocatalyst for seawater oxidation.During the seawater oxidation process,CeO_(2)is generated,effectively repelling Cl^(-)and inhibiting the formation of Cl O-,resulting in a notable enhancement in the oxidation activity and stability of alkaline seawater.The prepared Ce-Ni Fe LDH/NF requires only overpotential of 390 m V to achieve the current density of 1 A cm^(-2),while maintaining long-term stability for 500 h,outperforming the performance of Ni Fe LDH/NF(430 m V,150 h)by a significant margin.This study highlights the effectiveness of a Ce-doping strategy in augmenting the activity and stability of materials based on Ni Fe LDH in seawater electrolysis for oxygen evolution. 展开更多
关键词 Ce doping NiFe layered double hydroxide Seawater oxidation Electrocatalysis Cl^(-) repulsion
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Values of macular ganglion cell-inner plexiform layer and 10-2 visual field measurements in detecting and evaluating glaucoma
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作者 Hai-Jian Hu Ping Li +7 位作者 Bin Tong Yu-Lian Pang Hong-Dou Luo Fei-Fei Wang Chan Xiong Yu-Lin Yu Hai He Xu Zhang 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第5期852-860,共9页
AIM:To assess the performance of macular ganglion cell-inner plexiform layer thickness(mGCIPLT)and 10-2 visual field(VF)parameters in detecting early glaucoma and evaluating the severity of advanced glaucoma.METHODS:T... AIM:To assess the performance of macular ganglion cell-inner plexiform layer thickness(mGCIPLT)and 10-2 visual field(VF)parameters in detecting early glaucoma and evaluating the severity of advanced glaucoma.METHODS:Totally 127 eyes from 89 participants(36 eyes of 19 healthy participants,45 eyes of 31 early glaucoma patients and 46 eyes of 39 advanced glaucoma patients)were included.The relationships between the optical coherence tomography(OCT)-derived parameters and VF sensitivity were determined.Patients with early glaucoma were divided into eyes with or without central 10°of the VF damages(CVFDs),and the diagnostic performances of OCT-derived parameters were assessed.RESULTS:In early glaucoma,the mGCIPLT was significantly correlated with 10-2 VF pattern standard deviation(PSD;with average mGCIPLT:β=-0.046,95%CI,-0.067 to-0.024,P<0.001).In advanced glaucoma,the mGCIPLT was related to the 24-2 VF mean deviation(MD;with average mGCIPLT:β=0.397,95%CI,0.199 to 0.595,P<0.001),10-2 VF MD(with average mGCIPLT:β=0.762,95%CI,0.485 to 1.038,P<0.001)and 24-2 VF PSD(with average mGCIPLT:β=0.244,95%CI,0.124 to 0.364,P<0.001).Except for the minimum and superotemporal mGCIPLT,the decrease of mGCIPLT in early glaucomatous eyes with CVFDs was more severe than that of early glaucomatous eyes without CVFDs.The area under the curve(AUC)of the average mGCIPLT(AUC=0.949,95%CI,0.868 to 0.982)was greater than that of the average circumpapillary retinal nerve fiber layer thickness(cpRNFLT;AUC=0.827,95%CI,0.674 to 0.918)and rim area(AUC=0.799,95%CI,0.610 to 0.907)in early glaucomatous eyes with CVFDs versus normal eyes.CONCLUSION:The 10-2 VF and mGCIPLT parameters are complementary to 24-2 VF,cpRNFLT and ONH parameters,especially in detecting early glaucoma with CVFDs and evaluating the severity of advanced glaucoma in group level. 展开更多
关键词 10-2 visual field ganglion cell-inner plexiform layer retinal nerve fiber layer thickness GLAUCOMA
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Cross-Layer Adaptive Resource Allocation Algorithm with Diverse QoS Requirements for Single-Cell OFDMA Systems 被引量:14
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作者 Li Zeng Xi Li +1 位作者 Hong Ji Ke Wang 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2015年第1期15-22,共8页
The orthogonal frequency division multiple access( OFDMA) based communication system has been considered as the main trend of next-Generation communication system. But the existing resource allocation algorithm design... The orthogonal frequency division multiple access( OFDMA) based communication system has been considered as the main trend of next-Generation communication system. But the existing resource allocation algorithm designed for such system is always with high complexity thus hard to be realized. To solve such problem with the constraints of spectrum efficiency and buffer state,a novel cross-layer resource allocation algorithm( RAA) is proposed in this paper. The goal of our RAA is to maximize the system throughput while satisfying several practical constraints,such as fairness among services,head of line( Ho L) delay and diverse quality of service( Qo S) requirements. Due to these constraints,finding the optimal solution becomes a NPhard problem. Therefore in this paper a novel method to solve such problem with acceptable complexity is proposed within following steps: firstly,based on the link state we formulate the ideal subchannel allocation strategy as a convex optimization problem,which can be efficiently solved by our proposed lagrange multiplier technique subchannel allocation( LMTSA) algorithm; secondly,according to the obtained channel allocation matrix,a power allocation algorithm based on the water-filling power allocation( WPA) idea is deployed to get the optimal power allocation matrix combining with adaptive modulation and coding( AMC); finally,through a greedy algorithm,the ultimate subchannel and power allocation matrix can be obtained based on iterative method. The simulation results illustrate that we can achieve the higher throughput and better Qo S performance than the widely-used maximum throughput( MT) algorithm and round robin( RR) algorithm. 展开更多
关键词 OFDMA system RESOURCE ALLOCATION cross-layer DIVER
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基于YOLOv5-RF的糙米内部裂纹识别方法研究
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作者 张续博 张家瑜 +3 位作者 贲宗友 王逸凡 曾雨可 陈坤杰 《南京农业大学学报》 CAS CSCD 北大核心 2024年第4期792-802,共11页
[目的]为准确识别糙米内部裂纹,提出了一种基于改进YOLOv5l的糙米裂纹识别算法——YOLOv5-RF。[方法]使用深度卷积代替CBS(convolution+batch normalization+sigmoid linear unit)模块中的普通卷积构建出DWBS(depthwise convolution+bat... [目的]为准确识别糙米内部裂纹,提出了一种基于改进YOLOv5l的糙米裂纹识别算法——YOLOv5-RF。[方法]使用深度卷积代替CBS(convolution+batch normalization+sigmoid linear unit)模块中的普通卷积构建出DWBS(depthwise convolution+batch normalization+sigmoid linear unit)模块,然后将DWBS模块堆叠成辅助骨干网络,再与原始的Darknet-53主干网络相结合形成基于DWBS模块的同级复合骨干网络,以提高糙米内部裂纹特征提取能力;在颈部网络使用逆向连接层来增强解码端特征的丰富性,用于提高解码端对糙米内部裂纹的识别能力;利用CBAM(convolutional block attention module)注意力模块调整SPPF(spatial pyramid pooling-fast)模块的通道注意力表达,通过构建一种SPPF模块与CBAM模块结合的网络结构来提高编码阶段的语义信息表达质量。[结果]所提出的YOLOv5-RF算法的平均准确率、召回率和准确率分别为94.01%、86.92%、90.85%,相比YOLOv5l算法分别提升了4.72%、6.23%、1.23%,但添加模块对模型检测速度的影响却很小。[结论]所提方法能够准确进行糙米内部裂纹的识别,可为稻谷爆腰率检测提供技术参考。 展开更多
关键词 糙米裂纹 目标识别 特征信号增强 逆向连接层
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基于YOLO-Pose的城市街景小目标行人姿态估计算法
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作者 马明旭 马宏 宋华伟 《计算机工程》 CAS CSCD 北大核心 2024年第4期177-186,共10页
现有的姿态估计算法在城市街景中对小目标行人的检测效果不佳。针对该问题,提出一种基于YOLO-Pose的小目标行人姿态估计算法YOLO-Pose-CBAM。通过引入CBAM注意力机制模块,在不增加过多计算量的前提下,增强网络聚焦小目标行人区域的能力... 现有的姿态估计算法在城市街景中对小目标行人的检测效果不佳。针对该问题,提出一种基于YOLO-Pose的小目标行人姿态估计算法YOLO-Pose-CBAM。通过引入CBAM注意力机制模块,在不增加过多计算量的前提下,增强网络聚焦小目标行人区域的能力,提升算法对小目标行人的敏感度,同时在主干网络中使用4个不同尺寸的检测头,丰富算法对图片中不同大小行人的检测手段;在骨干网络和颈部之间架设2条跨层级联通道,提升浅层网络与深层网络之间的特征融合能力,进一步增强信息交流,降低小目标行人漏检率;引入SIoU重新定义边界框回归的定位损失函数,加快训练的收敛速度,提高检测精度;采用k-means++算法代替k-means算法对数据集中标注的锚框进行聚类,避免聚类中心初始化时导致的局部最优解问题,从而选择出更适合检测小目标行人的锚框。对比实验结果表明,在小目标行人Wider Keypoints数据集上,所提算法相较于YOLO-Pose和YOLOv7-Pose在平均精度上分别提升了4.6和6.5个百分比。 展开更多
关键词 YOLO-Pose算法 姿态估计 跨层级联 CBAM注意力机制 SIo U损失函数 k-means++算法
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A CROSS-LAYER STRATEGY FOR COOPERATIVE DIVERSITY IN WIRELESS SENSOR NETWORKS 被引量:1
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作者 ChenYongrui YangYang YiWeidong 《Journal of Electronics(China)》 2012年第1期33-38,共6页
We investigate the problem of how to minimize the energy consumption in multi-hop Wireless Sensor Network (WSN),under the constraint of end-to-end reliability Quality of Seervice (QoS) requirement.Based on the investi... We investigate the problem of how to minimize the energy consumption in multi-hop Wireless Sensor Network (WSN),under the constraint of end-to-end reliability Quality of Seervice (QoS) requirement.Based on the investigation,we jointly consider the routing,relay selection and power allocation algorithm,and present a novel distributed cross-layer strategy using opportunistic relaying scheme for cooperative communication.The results show that under the same QoS requirement,the proposed cross-layer strategy performs better than other cross-layer cooperative communication algorithms in energy efficiency.We also investigated the impact of several parameters on the energy efficiency of the cooperative communication in WSNs,thus can be used to provide guidelines to decide when and how to apply cooperation for a given setup. 展开更多
关键词 Wireless Sensor Network (WSN) cross-layer design Cooperative diversity Opportun-istic relaying
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Novel Optimized Cross-Layer Design with Maximum Weighted Capacity Based Resource Allocation for AMC/HARQ Wireless Networks 被引量:1
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作者 Reham A. El-Mayet Hesham M. El-Badawy Salwa H. Elramly 《Wireless Engineering and Technology》 2013年第2期77-86,共10页
To provide quality-of service (QoS) guarantees for heterogeneous applications, most recent wireless communications technologies and standards combine the error-correcting capability of hybrid automatic repeat request ... To provide quality-of service (QoS) guarantees for heterogeneous applications, most recent wireless communications technologies and standards combine the error-correcting capability of hybrid automatic repeat request (HARQ) schemes at the data link layer (DLL) with the adaptation ability of the adaptive modulation and coding (AMC) modes at the physical layer (PHY) layer. This paper aims to investigate the aggregated system capacity as well as the breakdown of this capacity for different ACM modes in each HARQ scheme. This investigation was done by using maximum weighted capacity (MWC) resource allocation at the PHY layer in conjunction with a novel packet error rate (PER)-based scheduling at the medium access control (MAC) layer. As a result, the dominant AMC mode corresponding to channel SNR was available. 展开更多
关键词 AMC cross-layer Design HARQ Nakagami-m FADING Channel QoS
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An Energy-Efficient Access Control Algorithm with Cross-Layer Optimization in Wireless Sensor Networks 被引量:1
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作者 Zhi Chen Shaoqian Li 《Wireless Sensor Network》 2010年第2期168-172,共5页
This paper presents a wireless sensor network (WSN) access control algorithm designed to minimize WSN node energy consumption. Based on slotted ALOHA protocol, this algorithm incorporates the power control of physical... This paper presents a wireless sensor network (WSN) access control algorithm designed to minimize WSN node energy consumption. Based on slotted ALOHA protocol, this algorithm incorporates the power control of physical layer, the transmitting probability of medium access control (MAC) layer, and the automatic repeat request (ARQ) of link layer. In this algorithm, a cross-layer optimization is preformed to minimizing the energy consuming per bit. Through theory deducing, the transmitting probability and transmitting power level is determined, and the relationship between energy consuming per bit and throughput per node is provided. Analytical results show that the cross-layer algorithm results in a significant energy savings relative to layered design subject to the same throughput per node, and the energy saving is extraordinary in the low throughput region. 展开更多
关键词 Wireless Sensor Network (WSN) cross-layer Design ENERGY Efficient ENERGY Consumption PER Bit THROUGHPUT
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A Simplified Method for the Stress Analysis of Underground Transfer Structures Crossing Multiple Subway Tunnels
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作者 Shen Yan Dajiang Geng +2 位作者 Ning Dai Mingjian Long Zhicheng Bai 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第6期2893-2915,共23页
According to the design specifications,the construction of extended piles involves traversing the tunnel’s upper region and extending to the underlying rock layer.To address this challenge,a subterranean transfer str... According to the design specifications,the construction of extended piles involves traversing the tunnel’s upper region and extending to the underlying rock layer.To address this challenge,a subterranean transfer structure spanning multiple subway tunnels was proposed.Deliberating on the function of piles in the transfer structure as springs with axial and bending stiffness,and taking into account the force balance and deformation coordination conditions of beams and plates within the transfer structure,we established a simplified mechanical model that incorporates soil stratification by combining it with the Winkler elastic foundation beam model.The resolved established simplifiedmechanicalmodel employed finite difference technology and the Newton-Simpsonmethod,elucidating the mechanical mechanism of the transfer structure.The research findings suggest that the load carried by the upper structural columns can be transferred to the pile foundation beneath the beams through the transfer structure,subsequently reaching the deep soil layer and ensuring minimal impact on adjacent tunnels.The established simplified analysis method can be used for stress analysis of the transfer structure,concurrently considering soil stratification,pile foundation behavior,and plate action.The pile length,pile section size,and beam section size within the transfer structure should account for the characteristics of the upper load,ensuring an even distribution of the beam bending moment. 展开更多
关键词 crossing tunnels transfer structure force mechanism simplify analysis layered soil mass
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Delivering audiovisual content with MPEG-21-enabled cross-layer QoS adaptation
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作者 AHMED Toufik DJAMA Ismail 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第5期784-793,共10页
Future multimedia communication systems have to support the user’s needs, the terminal capabilities, the content specification and the underlying networking technologies. The related protocols and applications must b... Future multimedia communication systems have to support the user’s needs, the terminal capabilities, the content specification and the underlying networking technologies. The related protocols and applications must be designed from this integration perspective in a cross-layer centric manner. In this paper, we propose an implementation of a streaming service (e.g., Television over IP service) with a unified QoS management concept that enables an IP driven integration of different system components (terminal, user, content, and network). The MPEG-21 framework is used to provide a common support for imple- menting and managing the end-to-end QoS. The main focus of this paper is on the architecture design, protocols specification and implementation evaluation. Performance evaluations using PSNR and SSIM objective video quality metrics show the benefit of the proposed MPEG-21-enabled cross-layer adaptation. 展开更多
关键词 cross-layer adaptation MPEG-21 MULTIMEDIA framework Real-time streaming QoS
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Oscillatory Dynamics of a Spherical Solid in a Liquid in an Axisymmetric Variable Cross Section Channel
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作者 Ivan Karpunin 《Fluid Dynamics & Materials Processing》 EI 2024年第6期1219-1232,共14页
The dynamics of a solid spherical body in an oscillating liquid flow in a vertical axisymmetric channel of variable cross section is experimentally studied.It is shown that the oscillating liquid leads to the generati... The dynamics of a solid spherical body in an oscillating liquid flow in a vertical axisymmetric channel of variable cross section is experimentally studied.It is shown that the oscillating liquid leads to the generation of intense averaged flows in each of the channel segments.The intensity and direction of these flows depend on the dimensionless oscillating frequency.In the region of studied frequencies,the dynamics of the considered body is examined when the primary vortices emerging in the flow occupy the whole region in each segment.For a fixed frequency,an increase in the oscillation amplitude leads to a phase-inclusion holding effect,i.e.,the body occupies a quasi-stationary position in one of the cells of the vertical channel,while oscillating around its average position.It is also shown that the oscillating motion of a liquid column generates an averaged force acting on the body,the magnitude of which depends on the properties of the body and its position in the channel.The quasi-stationary position is determined by the relative density and size of the body,as well as the dimensionless frequency.The behavior of the body as a function of the amplitude and frequency of fluid oscillation and relative size is discussed in detail.Such findings may be used in the future to control the position of a phase inclusion and/or to strengthen mass transfer effects in a channel of variable cross section by means of fluid oscillations. 展开更多
关键词 Phase inclusion axisymmetric channel variable cross section oscillations dimensionless frequency averaged force viscous boundary layer
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Cross-layer Enhancement to Multi-hop Routing in Sensor Networks: an Empirical Study
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作者 SHANG Zhi-Jun WANG Jun YU Hai-Bin 《自动化学报》 EI CSCD 北大核心 2006年第6期875-880,共6页
Lossy link is one of the unique characteristics in random-deployed sensor networks. We envision that robustness and reliability of routing cannot be ensured purely in network layer. Our idea is to enhance the performa... Lossy link is one of the unique characteristics in random-deployed sensor networks. We envision that robustness and reliability of routing cannot be ensured purely in network layer. Our idea is to enhance the performance of routing protocol by cross-layer interaction. We modified mint protocol, a routing protocol in TinyOS and proposed an enhanced version of mint called PA-mint. A transmission power control interface is added to network layer in PA-mint. When routing performance of the current network is not satisfied, PA-mint monotonically increases the transmission power via the interface we added. PA-mint is able to connect orphan nodes and robust to node mobility or key nodes failure. In the case that automatic request retransmission is employed, the number of retransmissions can be reduced by PA-mint. Results from experiments show that PA-mint increases the reliability and robustness of routing protocol by cross-layer interaction. 展开更多
关键词 Sensor networks ROUTING cross-layer design
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Cross-Layer Design Based Optimized Link State Routing Protocol for Wireless Mesh Networks
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作者 Huai-Yu Wen Guang-Chun Luo 《Journal of Electronic Science and Technology》 CAS 2011年第4期368-372,共5页
A proactive routing protocol CL-OLSR (cross-layer based optimized link state routing) by using a brand-new routing metric CLM (cross-layer metric) is proposed. CL-OLSR takes into account four link quality impact f... A proactive routing protocol CL-OLSR (cross-layer based optimized link state routing) by using a brand-new routing metric CLM (cross-layer metric) is proposed. CL-OLSR takes into account four link quality impact factors in route calculation through the cross-layer operation mechanism: the node available bandwidth, the node load, the link delivery rate, and the link interference, and thus the effect of route selection is optimized greatly. The simulation results show that the proposed CL-OLSR protocol can not only improve the network throughput to a large extent, but also reduce the end-to-end delay, while achieving load balance route results. 展开更多
关键词 cross-layer design proactive routing routing protocol wireless mesh network.
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A NOVEL CROSS-LAYER STRATEGY OF VIDEO TRANSMISSION TO SOLVE PERFORMANCE ANOMALY IN MULTI-RATE IEEE 802.11 NETWORKS
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作者 Tang Guijin Zhu Xiuchang 《Journal of Electronics(China)》 2011年第3期349-358,共10页
When wireless hosts use different rates to transmit data in IEEE 802.11 networks, it will take on the state of performance anomaly which will severely decrease the throughputs of all the higher rate hosts. Hence, it i... When wireless hosts use different rates to transmit data in IEEE 802.11 networks, it will take on the state of performance anomaly which will severely decrease the throughputs of all the higher rate hosts. Hence, it is bad for video service transmission. Considering that video is very sensitive to packet delivery delay but can tolerate some packet losses, we propose a novel cross-layer scheme which takes these two characteristics into consideration. Firstly, the maximum number of retransmissions for a video Medium Access Control (MAC) frame is computed in MAC layer according to video frame rate requirement of application layer and current access delay of MAC layer. Secondly, within the margin of the tolerant Packet Loss Rate (PLR) of application layer, several video MAC frames are allowed to drop so that we can adaptively select the transmission rate as high as possible for the rest of video MAC frames in terms of current channel quality and the maximum number of retransmissions. Experiment results show that the proposed method can reduce the delay and jitter of video service and improve the throughputs of fast hosts. Therefore, it increases the quality of reconstructed video to a certain extent and relieves the performance anomaly of network effectively. 展开更多
关键词 MULTI-RATE Video transmission IEEE 802.11 Performance anomaly cross-layer
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Performance of Cross-Layer Design with Power Allocation in Space-Time Coded MIMO Systems
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作者 杨定礼 刘岩 虞湘宾 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2014年第4期431-439,共9页
A cross-layer design(CLD)scheme with combination of power allocation,adaptive modulation(AM)and automatic repeat request(ARQ)is presented for space-time coded MIMO system under imperfect feedback,and the corresponding... A cross-layer design(CLD)scheme with combination of power allocation,adaptive modulation(AM)and automatic repeat request(ARQ)is presented for space-time coded MIMO system under imperfect feedback,and the corresponding system performance is investigated in a Rayleigh fading channel.Based on imperfect feedback information,a suboptimal power allocation(PA)scheme is derived to maximize the average spectral efficiency(SE)of the system.The scheme is based on a so-called compressed SNR criterion,and has a closed-form expression for positive power allocation,thus being computationally efficient.Moreover,it can improve SE of the presented CLD.Besides,due to better approximation,it obtains the performance close to the existing optimal approach which requires numerical search.Simulation results show that the proposed CLD with PA can achieve higher SE than the conventional CLD with equal power allocation scheme,and has almost the same performance as CLD with optimal PA.However,it has lower calculation complexity. 展开更多
关键词 cross-layer design(CLD) power allocation(PA) space-time coding spectral efficiency(SE) packet error rate(PER)
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A Novel Cross-Layer Scheduling Algorithm for OFDMA-Based WiMAX Networks
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作者 Ronak Farhadi Vahid Tabataba Vakili Shahriar Shirvani Moghaddam 《International Journal of Communications, Network and System Sciences》 2011年第2期98-103,共6页
IEEE 802.16e based WiMAX networks promise a desirable available quality of service for mobile users and scheduling algorithms provide the best effective use of network resources in it. In this paper, we propose a nove... IEEE 802.16e based WiMAX networks promise a desirable available quality of service for mobile users and scheduling algorithms provide the best effective use of network resources in it. In this paper, we propose a novel cross-layer scheduling algorithm for OFDMA-based WiMAX networks. Our scheme employs a priority function at the MAC layer and a slot allocation policy at physical layer and by interaction between these two layers specifies the best allocation for each connection. Simulation results show performance of proposed scheme in comparison with two other well-known scheduling algorithms, MAX-SNR scheduling and Proportional Fairness (PF) scheduling. Our proposed cross-layer algorithm outperforms the other algorithms in delay and packet loss rate values for real-time services. 展开更多
关键词 cross-layer IEEE802.16E OFDMA QoS SCHEDULING WIMAX
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A Cross-Layer Scheme for Handover in 802.16e Network with F-HMIPv6 Mobility
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作者 Yi ZHENG Yong ZHANG +1 位作者 Yinglei TENG Mei SONG 《Communications and Network》 2009年第1期35-41,共7页
IEEE802.16e is the major global cellular wireless standard that enables low-cost mobile Internet application. However, existing handover process system still has latency affects time-sensitive applications. In this pa... IEEE802.16e is the major global cellular wireless standard that enables low-cost mobile Internet application. However, existing handover process system still has latency affects time-sensitive applications. In this paper, the handover procedures of 802.16e and Fast Handover for Hierarchical MIPv6 (F-HMIPv6) are reconstructed to achieve a better transmission performance. The concept of cross layer design is adopted to refine the existing handover procedure specified in 802.16e MAC layer and F-HMIPv6. More specifically, layer2 and layer3 signaling messages for handover are analyzed and combined/interleaved to optimize the handover performance. Extensive simulations show that the proposed scheme in this paper is superior to the other scheme proposed by IETF. 展开更多
关键词 HANDOVER cross layer 802.16e F-HMIPV6
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QUALITY-AWARE CROSS-LAYER SCHEDULING FOR ROBUST VIDEO STREAMING OVER WIRELESS CHANNELS
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作者 Liu Hao Zhao Shuguang Qian Jianmin 《Journal of Electronics(China)》 2011年第3期303-312,共10页
In the case of video streaming over wireless channels, burst errors may lead to serious video quality degradation. By jointly exploiting the scheduling mechanism on different communication layers, this paper proposes ... In the case of video streaming over wireless channels, burst errors may lead to serious video quality degradation. By jointly exploiting the scheduling mechanism on different communication layers, this paper proposes a quality-aware cross-layer scheduling scheme to achieve unequal error control for each Latency-constraint Frame Set (LFS) of a video stream. After a network-layer agent at base station firstly utilizes the network-layer packet scheduling to provide packet-granularity importance classifi-cation for the current LFS, a link-layer agent at base station further utilizes the Radio-Link-Unit (RLU) scheduling to implement finer selective retransmission of the current LFS. Under scheduling delay and bandwidth constraints, the proposed scheme can be aware of the application-layer quality and time-varying channel conditions, and hence burst errors can simply be shifted to lower-priority transmission units in the current LFS. Simulation results demonstrate that the proposed scheme has strong robustness against burst errors, and thus improves the overall received quality of the video stream over wireless channels. 展开更多
关键词 Unequal error control Video stream Burst errors cross-layer scheduling
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Cross-layer design of combining AMC with HARQ in cooperative relay system with perfect and imperfect CSI
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作者 唐伦 张荣荣 陈前斌 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2012年第4期118-128,共11页
A cross-layer design which combines adaptive modulation and coding (AMC) at the physical layer with a hybrid automatic repeat request (HARQ) protocol at the data link layer (LL) is presented, in cooperative relay syst... A cross-layer design which combines adaptive modulation and coding (AMC) at the physical layer with a hybrid automatic repeat request (HARQ) protocol at the data link layer (LL) is presented, in cooperative relay system over Nakagami-m fading channels with perfect and imperfect channel state information (CSI). In order to maximize spectral efficiency (SE) under delay and packet error rate (PER) performance constraints, a state transition model and an optimization framework with perfect CSI are presented. Then the framework is extended to cooperative relay system with imperfect CSI. The numerical results show that the scheme can achieve maximum SE while satisfying transmitting delay requirements. Compared with the imperfect CSI, the average PER with perfect CSI is much lower and the spectral efficiency is much higher. 展开更多
关键词 COOPERATIVE relay system cross-layer design and optimization adaptive modulation and coding (AMC) hybrid automatic REPEAT request (HARQ) PERFECT channel state information(CSI) imperfect CSI
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Energy-Efficient Cross-Layer Optimization for Wireless Sensor Networks
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作者 Yongqiang Fei Peng Zhang Yuping Zhao 《Communications and Network》 2013年第3期493-497,共5页
In this paper, we propose a cross-layer design combining adaptive modulation coding (AMC) and automatic repeat request (ARQ) to minimize the bit energy consumption under both packet loss rate and retransmission delay ... In this paper, we propose a cross-layer design combining adaptive modulation coding (AMC) and automatic repeat request (ARQ) to minimize the bit energy consumption under both packet loss rate and retransmission delay constraints. We analyze the best constellation size of M-ary square quadrature amplitude modulation (MQAM) in different distance, and give advice on retransmission limits under different packet loss rates. The impacts of path loss fading and additive white Gaussian noise (AWGN)are taken into consideration. The computation of energy consumption includes the circuit, transmission and retransmission energies at both transmitter and receiver sides. Numerical results are obtained to verify the validity of our design. We also show that the retransmission benefit varies with the packet loss rate constraint. 展开更多
关键词 cross-layer Design Energy CONSUMPTION Green MODULATION AMC ARQ
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