基于DHT的IPv4/IPv6过渡机制(英文)

IPv4 and IPv6 will coexist for many years during the transition period from the traditional IPv4-based Internet to an IPv6-based Internet.DHTLayer,a novel IPv4/IPv6 transition mechanism based on Distributed Hash Table(DHT) is presented in this paper.It can fully support IPv4 and IPv6 inter-operation.DHTLayer employs a DHT overlay to maintain the routing information between IPv4 and IPv6.It decouples path selection from packet delivery.In DHTLayer,the Looking-Up Route Path is responsible for selecting paths,...     

Query routing mismatch alleviation architecture for P2P file lookup in MANETs

A cross-layer optimized query routing mismatch alleviation(QRMA)architecture is proposed to mitigate the problem of query routing mismatch(QRM)phenomenon between the structured peer to peer(P2P)overlay and the routing layer in mobile Ad-hoc networks(MANETs),which is an important issue that results in the inefficiency of lookup process in the system.Explicated with the representative Chord protocol,the proposal exploits the information of topologic neighbors in the routing layer of MANETs to find if there is any optimized alternative next hop in P2P overlay during conventional lookup progress.Once an alternative next hop is detected,it will take the shortcut to accelerate the query procedure and therefore alleviate the QRM problem in scalable MANETs without any assistance of affiliation equipments such as GPS device.The probability of finding out such an alternative node is formulated and the factors that could increase the chance are discussed.The simulation results show that the proposed architecture can effectively alleviate the QRM problem and significantly improve the system performance compared with the conventional mechanism.     

黑杨受拉木纤维细胞组分及孔隙分布拉曼光谱成像数据研究

倾斜阔叶木枝干弯曲部位的上端在拉伸应力影响下通常会形成受拉木.区别于受拉伸部位下方的对应木,受拉木细胞壁通常会出现理化特性变异的现象,主要归因于细胞次生壁内侧胶质层的形成.采用透射电子显微成像技术揭示了黑杨受拉木与对应木纤维细胞壁分层结构特点,并借助532 nm共聚焦显微拉曼光谱成像(空间分辨率约为0.5μm)及图像叠...     

广播电视传输覆盖网与无线电技术应用探究

科学技术的发展对广电事业产生了积极影响,保证了广电信号良好的传输状况。为了丰富广播电视传输方面的技术内涵,提高节目播出质量,需要对与之相关的覆盖物与无线电技术应用进行充分考虑,确保广播电视信号传输有效性,在技术层面上为其高效传输及潜在应用价值提升等提供有效保障。文章将对广播电视传输覆盖网与无线电技术应用进行系统阐述。     

Performance evaluation of nonlinear energy scavenging overlay networks

This paper investigates a nonlinear energy scavenging overlay network (NLESON) wherein a primary source (PS) communicates with a primary destination (PD) probably under aid of a secondary source (SS) who communicates with a secondary destination (SD). SS is a power-constrained device, and thence, its operation relies on energy harvested by a practical nonlinear energy scavenger. To support PS and exploit the harvested energy at most, SS adaptively switches between single and superposition modes where the single mode allows SS to transmit solely its signal with the entire harvested energy and the superposition mode asks SS to transmit both—its signal and amplified primary signal—with different power fractions. Moreover, for increasing the probability of successfully decoding primary signal at PD and SD, which then reduces considerably primary interference on secondary signal in the superposition mode, we leverage both direct channels (PS-PD and PS-SD) and apply both signal combining paradigms (maximum ratio combining and selection combining). The outage/throughput performance of the NLESON is assessed quickly through the proposed closed-form expressions over $\kappa -\mu$ shadowed fading channels. Various results exposed the effectiveness of the aforementioned solutions for the NLESON and their flexibility in controlling system performance.