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Internet Applications (internet + application)
Selected AbstractsFROM EXOGENOUS TO ENDOGENOUS ECONOMIC NETWORKS: INTERNET APPLICATIONSJOURNAL OF ECONOMIC SURVEYS, Issue 5 2006Alessio D'Ignazio Abstract Economic agents' behaviour is affected by their position in a network, either exogenous or endogenous, in which they interact with a sub-set of neighbours only. The network's links, which may be generated by vertical and/or horizontal relations, or by more complex morphologies, may explain the transition between dynamic equilibria and the instability of economic aggregates. Moreover, networks shape strategic interaction among agents by determining their strategies; the problem of access and interconnection, particularly relevant in the Internet, is perhaps the best example. A two-way feedback between strategies and network structures arises instead when links are endogenous: those features are clearly shown in the mechanism underlying the formation of peering links and R & D networks. [source] A view of the data on P2P file-sharing systemsJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 10 2009Wai Gen Yee Peer-to-peer (P2P) file sharing is a leading Internet application. Millions of users use P2P file-sharing systems daily to search for and download files, accounting for a large portion of Internet traffic. Due to their scale, it is important to fully understand how these systems work. We analyze user queries and shared files collected on the Gnutella system, draw some conclusions on the nature of the application, and propose some research problems. [source] End-to-end QoS and global mobility management in an integrated satellite/terrestrial networkINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 1 2004P. Conforto Abstract For decades, the development of the Internet was driven by the purpose of providing applications to non-mobile users. No specific Quality of Service (QoS) requirement is necessary, other than ensuring reliability in the end-to-end data transfers. As such, best effort service model was deemed more than appropriate to satisfy the users' needs. Nevertheless, the scenario has changed in the last few years. A new population of nomadic users, who requires access to Internet services regardless of their location and mode of transportation is growing, while new typologies of Internet applications are being continuously developed, in which best effort service level may no longer be adequate. The SUITED project has been devised to address the emerging issues generated by this new and challenging scenario. SUITED aims at contributing towards the design and deployment of the Global Mobile Broadband System (GMBS), a unique satellite/terrestrial infrastructure, which will ensure that nomadic users have access to Internet services with a negotiated QoS. An overview of the main results achieved in the SUITED project is provided in this article. Some of the most innovative solutions developed by the SUITED team for the joint management of global mobility and end-to-end QoS support are presented. The SUITED demonstrator platform, which was developed to validate the system specifications, is also described. Finally, the results of the experimental measurement campaigns carried out with this platform are reported. Copyright © 2004 John Wiley & Sons, Ltd. [source] Signal-to-interference-plus-noise ratio estimation for wireless communication systems: Methods and analysisNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 5 2004Daniel R. Jeske Abstract The Signal-to-Interference-plus-Noise Ratio (SINR) is an important metric of wireless communication link quality. SINR estimates have several important applications. These include optimizing the transmit power level for a target quality of service, assisting with handoff decisions and dynamically adapting the data rate for wireless Internet applications. Accurate SINR estimation provides for both a more efficient system and a higher user-perceived quality of service. In this paper, we develop new SINR estimators and compare their mean squared error (MSE) performance. We show that our new estimators dominate estimators that have previously appeared in the literature with respect to MSE. The sequence of transmitted bits in wireless communication systems consists of both pilot bits (which are known both to the transmitter and receiver) and user bits (which are known only by the transmitter). The SINR estimators we consider alternatively depend exclusively on pilot bits, exclusively on user bits, or simultaneously use both pilot and user bits. In addition, we consider estimators that utilize smoothing and feedback mechanisms. Smoothed estimators are motivated by the fact that the interference component of the SINR changes relatively slowly with time, typically with the addition or departure of a user to the system. Feedback estimators are motivated by the fact that receivers typically decode bits correctly with a very high probability, and therefore user bits can be thought of as quasipilot bits. For each estimator discussed, we derive an exact or approximate formula for its MSE. Satterthwaite approximations, noncentral F distributions (singly and doubly) and distribution theory of quadratic forms are the key statistical tools used in developing the MSE formulas. In the case of approximate MSE formulas, we validate their accuracy using simulation techniques. The approximate MSE formulas, of interest in their own right for comparing the quality of the estimators, are also used for optimally combining estimators. In particular, we derive optimal weights for linearly combining an estimator based on pilot bits with an estimator based on user bits. The optimal weights depend on the MSE of the two estimators being combined, and thus the accurate approximate MSE formulas can conveniently be used. The optimal weights also depend on the unknown SINR, and therefore need to be estimated in order to construct a useable combined estimator. The impact on the MSE of the combined estimator due to estimating the weights is examined. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004 [source] Virtual Cities From Digital ImageryTHE PHOTOGRAMMETRIC RECORD, Issue 96 2000E. Gülch Increasing interest is being expressed in the use of virtual cities for many fields of application, ranging from planning and simulation to business, advertising and the games industry. Currently, the extraction of buildings from imagery is costly. However, recent developments in digital photogrammetry aim to produce more rapid and efficient methods of modelling three dimensional objects in urban environments. This paper presents a semi-automatic system for the extraction of buildings from digital aerial imagery with the aid of volumetric primitives. The user is supported by automated tools, for example matching tools, in order to reach the necessary efficiency. With an extraction time of about 20 s per building primitive, this method is competitive in terms of the performance of classical photogrammetric procedures, and also offers additional features for analysis, texture mapping and Internet applications. [source] The use of Geographic Information Systems in climatology and meteorology: COST 719METEOROLOGICAL APPLICATIONS, Issue 1 2005Izabela Dyras The COST Action 719 started in 2001 and presently 20 European countries are participating. The main objectives of the Action are to establish interfaces between GIS and meteorological data, assess the availability, contents and accessibility of meteorological and climatological data sets and encourage and foster European co-operation. The tasks are carried out within three working groups concentrated on issues such as data access and availability, methods of spatial interpolation and developing recommendations for standardised GIS applications. The applications that have been adopted mainly focus on three parameters, i.e. precipitation, temperature and energy balance for which three demonstration projects have been formulated. It is expected that the Action will result in recommendations for better and more cost-effective production of state-of-the-art meteorological and climatological information. Also an improvement of the co-operation between European countries in the application of GIS in the field of meteorology, climatology and environmental sciences should be achieved together with better-trained personnel within the operational and scientific divisions of national meteorological services. Additionally, the development of a visualisation system for climate data sets for internet applications is under preparation. This paper provides information concerning the work in progress on the demonstration projects made within COST 719. Copyright © 2005 Royal Meteorological Society. [source] The support of mobile internet applications in UMTS networks through the open service accessBELL LABS TECHNICAL JOURNAL, Issue 2 2001Musa R. Unmehopa Third-generation wireless networks are expected to enable the mobile Internet to become a reality, offering fast Internet access and high-speed data services to mobile subscribers. For network operators to allow for the rapid development of innovative value-added applications on the scale seen in the Internet today, the wireless core network needs to be opened up for third-party applications provided by independent software vendors (ISVs). The Third-Generation Partnership Project (3GPP) is currently working on the production of technical specifications to provide a mechanism that would permit ISVs a standard interface to access network capabilities traditionally available to network operators. Within 3GPP, this mechanism is commonly referred to as the open service access (OSA). This open service access is predominantly targeted at Universal Mobile Telecommunications System (UMTS) networks, allowing application developers to access the feature-rich core network capabilities. This open access enables network operators to offer innovative services to their subscribers allowing the ability to differentiate themselves in a competitive market. With the imminent commercial deployment of the General Packet Radio Service (GPRS), existing fixed-line Internet service providers (ISPs) can now offer mobile Internet to end users in a UMTS environment where the responsibility of the network operator is reduced to providing IP connectivity. The increased competition from ISPs poses a big threat to the revenue stream of the network operator. This paper explores the possibilities of OSA to facilitate network operators in providing the mutual support of network capabilities and Internet content. These possibilities would allow the network operator to become a value-added mobile Internet service provider (VAM-ISP). © 2002 Lucent Technologies Inc. [source] | ||||||||||