检索结果-南通市图书馆

Impact of tropospheric modelling on GNSS vertical precision:an empirical analysis based on a local active network

在线全文

学校读者我要写书评

暂无评论

International Journal of Digital Earth 2018年第9期11卷 880-896页

作者： MªSelmira Garrido MªClara de Lacy Ana MªRojas Department of Cartographic Geodetic and Photogrammetric EngineeringUniversity of JaénJaenSpain Center for Advanced Studies in Earth Sciences University of JaénJaenSpain Research group RNM282–Microgeodesia Jaén University of JaénJaenSpain

The troposphere affects Global Navigation Satellite System(GNSS)signals due to the variability of the refractive *** delay is a function of the satellite elevation angle and the altitude of the GNSS receiver and depends on the atmospheric *** the residual tropospheric delay is not modelled carefully a bias error will occur in the vertical *** order to analyse the precise altimetric positioning based on a local active network,four scenarios in Southern Spain with different topographical,environmental,and meteorological conditions are presented,considering both favourable and non-favourable *** use of surface meteorological observations allows us to take into account the tropospheric conditions instead of a standard atmosphere,but introduces a residual tropospheric bias which reduces the accuracy of precise GNSS ***,with short observation times it is recommended not to estimate troposphere parameters,but to use an a priori model together with the standard *** results confirm that it is possible to achieve centimetre-scale vertical accuracy and precision with real time kinematic positioning even with large elevation differences with respect to the nearest reference *** numerical results may be taken into consideration for improving the altimetric configuration of the local active network.

关键词： Altimetry GNSS meteorological data active network tropospheric refraction

Multi-Path Routing and Resource Allocation in active network

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2005年第2期10卷 398-404页

作者： XUWu-ping YANPu-liu WUMing SchoolofElectronicInformation WuhanUniversityWuhan430072HubeiChina

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 *** 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.

关键词： multi-path routing resource allocation congestion control active network multi-agent system

GPS Rapid Static and Kinematic Positioning Based on GPS active network

在线全文

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2003年第1期6卷 5-11页

作者： CHEN Wu HU Congwei CHEN Yongqi DING Xiaoli Simon Chi_wo Kowk Deparlynent of Land Surveying and Geo-lnformatics The Hong Kong Polytechnic University

This paper presents a data processing strategy for GPS kinematic positioning by using a GPS active network to model the GPS errors in double difference ***,the double difference residuals are estimated between the reference stations in the active *** the errors at a user station are predicted as the network corrections to user measurements,based on the location of the *** conventional kinematic positioning algorithms can be applied to determine the position of the user *** an example,continuous 24_hour GPS data in March 2001 has been processed by this *** clearly demonstrates that,after applying these corrections to a user within the network,both the success rate for ambiguity resolution and the positioning accuracy have been significantly improved.

关键词： GPS ambiguity active network network correction kinematic positioning

nanoscale communication networks： utilizing an active network architecture

在线全文

学校读者我要写书评

暂无评论

Frontiers of Materials Science 2011年第3期5卷 316-326页

作者： Stephen F. BUSH GE Global Research One Research Circle Niskayuna NY 12309 USA

A safe and reliable nication network will be of in vivo nanoscale commu- great benefit for medical diagnosis and monitoring as well as medical implant communication. This review article provides a brief introduction to nanoscale and molecular networking in general and provides opinions on the role of active networking for in vivo nanoscale information transport. While there are many in vivo communication mechanisms that can be leveraged, for example, forms of cell signaling, gap junctions, calcium and ion signaling, and circulatory borne communication, this review examines two in particular： molecular motor transport and neuronal information communication. Molecular motors transport molecules representing information and neural coding operates by means of the action potential; these mechan- isms are reviewed within the theoretical framework of an active network. This review suggests that an active networking paradigm is necessary at the nanoscale along with a new communication constraint, namely, minimiz- ing the communication impact upon the living environment. The goal is to assemble efficient nanoscale and molecular communication channels while minimizing disruption to the host organism.

关键词： nanoscale network molecular communication in vivo network active network molecular motor,neural coding

A Novel active network Architecture Based on Extensible Services Router

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Technology Letters 2003年第2期9卷 51-56页

作者：徐恪 XU Mingwei Wu Jianping Yu Zhongchao network Institute Department of Computer Science Tsinghua University Beijing 100084 P.R.China

active networks are a new kind of packet-switched networks in which packets have code fragments that are executed on the intermediary nodes (routers). The code can extend or modify the foundation architecture of a network. In this paper, the authors present a novel active network architecture combined with advantages of two major active networks technology based on extensible services router. The architecture consists of extensible service router, active extensible components server and key distribution center (KDC). Users can write extensible service components with programming interface. At the present time, we have finished the extensible services router prototype system based on Highly Efficient Router Operating System (HEROS), active extensible components server and KDC prototype system based on Linux.

关键词： computer networks extensible services active network authentication

Resources Management in active networks

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2003年第1期10卷 66-71页

作者： WANGJian-guo LIZeng-zhi KOUYan-an ComputerDepartment Xi'anInstituteofTechnologyXi’an710032P.R.China InstituteofComputerArchitecture&network Xi'anJiaotongUniversityXi’an710049P.R.China

In an active network, users can insert customized active codes into activenodes, to execute. Thus it needs more resources than those required by conventional networks, andthese resources must be effectively monitored and managed. Management policies in existing OSs aretoo complicated to apply to simple active packets. In this paper, we present new resourcesmanagement policies that are mainly adoped to manage CPU, storage and transmission ***, we use SPF algorithm to schedule and process active packets, and import an interval queuemethod to allocate transmission bandwidth, and use feedback mechanism to control congestion . At thesame time, we design some experiments on prototype systems with and without resources managementpolicies respectively. The experiments results show that management policies presented by us caneffectively manage resources in active nodes and can improve the performance of active networks.

关键词： active network active node resources management transmission bandwidth

Application and Development of Mobile Agent in AN

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2004年第1期11卷 73-78页

作者： XULi ZHENGBao-yu Department of Information Engineering NanjingUniversityofPostsandTelecommunicationNanjing210003P.R.China

active networks represent a significant step in the evolution of packet-switched networks. It aims to move dynamic computation within the network. Mobile agent technology is a novel paradigm for distributed computation. This paper discusses the applicability of mobile agent technology for the development of active networks, both security policy and resource management, and other expected application as well. Based on the discussion, it describes a general mobile agent based active network (AN) architecture at last.

关键词： active network mobile agent security management architecture