109 research outputs found

    Satellite Communications

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    This study is motivated by the need to give the reader a broad view of the developments, key concepts, and technologies related to information society evolution, with a focus on the wireless communications and geoinformation technologies and their role in the environment. Giving perspective, it aims at assisting people active in the industry, the public sector, and Earth science fields as well, by providing a base for their continued work and thinking

    Do market failures hamper the perspectives of broadband?

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    This report analyses the broadband market and asks whether a specific role of government is necessary. As broadband telecommunication is seen as a source of productivity gains, the European Union and other regions are encouraging the deployment of a secure broadband infrastructure. In the Netherlands, there is some concern whether the supply of broadband capacity will meet the strongly increasing demand. The main conclusions are that presently, given current broadband policy, no considerable market failures exist. Firms have adequate incentives to invest in broadband, partly induced by specific regulation of access to the local copper loop. Hence, there is no need for changes in current broadband policy. Market failures in terms of knowledge spillovers are taken care of by other policies. As the broadband markets are very dynamic, unforeseen developments may emerge such as the appearance of new dominant techniques and market players. The best strategy for the government, in particular the competition authority, is to continuously monitor these markets, making timely intervention easier when needed.

    ICT and local development: a case study of the metropolitan area of Cagliari

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    This paper provides a broad description of the local infrastructure and economy in the Cagliari area, with a special focus on the sector of information and communication technology. It argues that, while the ICT sector has become in time a significant industrial reality in the Cagliari area, it has not reached the dimensions and status of a veritable technology district, and the drive for innovation and corporate success appears to have lost its momentum

    Adaptive Modulation Schemes for Underwater Acoustic OFDM Communication

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    High data rate communication is challenging in underwater acoustic (UA) communication as UA channels vary fast along with the environmental factors. A real-time Orthogonal frequency-division multiplexing (OFDM) based adaptive UA communication system is studied in this research employing the National Instruments (NI) LabVIEW software and NI CompactDAQ device. The developed adaptive modulation schemes enhance the reliability of communication, guarantee continuous connectivity, ensure maximum performance under a fixed BER at all times and boost data rate

    Future policy in telecommunications: an analytical framework

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    CPB investigates future policy issues within the telecommunication sector with the aid of so-called 'exogenous developments'. �The aim is to analyse a limited number of developments that are exogenous to policymakers. The policy issues that emerge depend mainly on the trade-off between so-called static and dynamic efficiency. The three exogenous developments we consider are: growth of internet through mobile, the outpacing of demand for supply of broad band internet access, and the concentration and consolidation of the European mobile industry. This paper describes the policy trade-offs for each of the exogenous developments, charts the likely development of the industry given certain key drivers, and suggests ways in which the market can be pushed towards the optimum state of high dynamic and high static efficiency. This work is co-financed by OPTA.

    Available bandwidth estimation in smart VPN bonding technique based on a NARX neural network

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    Today many applications require a high Quality of Service (QoS) to the network, especially for real time applications like VoIP services, video/audio conferences, video surveillance, high definition video transmission, etc. Besides, there are many application scenarios for which it is essential to guarantee high QoS in high speed mobility context using an Internet Mobile access. However, internet mobile networks are not designed to support the real-time data traffic due to many factors such as resource sharing, traffic congestion, radio link, coverage, etc., which affect the Quality of Experience (QoE). In order to improve the QoS in mobility scenarios, the authors propose a new technique named "Smart VPN Bonding" which is based on aggregation of two or more internet mobile accesses and is able to provide a higher end-to-end available bandwidth due to an adaptive load balancing algorithm. In this paper, in order to dynamically establish the correct load balancing weights of the smart VPN bonder, a neural network approach to predict the main Key Performance Indicators (KPIs) values in a determinate geographical point is proposed

    OFDM techniques for multimedia data transmission

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    Orthogonal Frequency Division Multiplexing (OFDM) is an efficient parallel data transmission scheme that has relatively recently become popular in both wired and wireless communication systems for the transmission of multimedia data. OFDM can be found at the core of well known systems such as digital television/radio broadcasting, ADSL internet and wireless LANs. Research into the OFDM field continually looks at different techniques to attempt to make this type of transmission more efficient. More recent works in this area have considered the benefits of using wavelet transforms in place of the Fourier transforms traditionally used in OFDM systems and other works have looked at data compression as a method of increasing throughput in these types of transmission systems. The work presented in this thesis considers the transmission of image and video data in traditional OFDM transmission and discusses the strengths and weaknesses of this method. This thesis also proposes a new type of OFDM system that combines transmission and data compression into one block. By merging these two processes into one the complexity of the system is reduced, therefore promising to increase system efficiency. The results presented in this thesis show the novel compressive OFDM method performs well in channels with a low signal-to-noise ratio. Comparisons with traditional OFDM with lossy compression show a large improvement in the quality of the data received with the new system when used in these noisy channel environments. The results also show superior results are obtained when transmitting image and video data using the new method, the high correlative properties of images are ideal for effective transmission using the new technique. The new transmission technique proposed in this thesis also gives good results when considering computation time. When compared to MATLAB simulations of a traditional DFT-based OFDM system with a separate compression block, the proposed transmission method was able to reduce the computation time by between a half to three-quarters. This decrease in computational complexity also contributes to transmission efficiency when considering the new method

    SCADA and related technologies for irrigation district modernization

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    Presented at SCADA and related technologies for irrigation district modernization: a USCID water management conference on October 26-29, 2005 in Vancouver, Washington.Includes bibliographical references.Overview of Supervisory Control and Data Acquisition (SCADA) -- Total Channel Control™ - The value of automation in irrigation distribution systems -- Design and implementation of an irrigation canal SCADA -- All American Canal Monitoring Project -- Taking closed piping flowmeters to the next level - new technologies support trends in data logging and SCADA systems -- Real-time model-based dam automation: a case study of the Piute Dam -- Effective implementation of algorithm theory into PLCs -- Optimal fuzzy control for canal control structures -- SCADA over Zigbee™ -- Synchronous radio modem technology for affordable irrigation SCADA systems -- A suggested criteria for the selection of RTUs and sensors -- Irrigation canals in Spain: the integral process of modernization -- Ten years of SCADA data quality control and utilization for system management and planning modernization -- Moderately priced SCADA implementation -- Increasing peak power generation using SCADA and automation: a case study of the Kaweah River Power Authority -- Eastern Irrigation District canal automation and Supervisory Control and Data Acquisition (SCADA) -- Case study on design and construction of a regulating reservoir pumping station -- Saving water with Total Channel Control® in the Macalister Irrigation District, Australia -- Leveraging SCADA to modernize operations in the Klamath Irrigation Project -- A 2005 update on the installation of a VFD/SCADA system at Sutter Mutual Water Company -- Truckee Carson Irrigation District Turnout Water Measurement Program -- The myth of a "Turnkey" SCADA system and other lessons learned -- Canal modernization in Central California Irrigation District - case study -- Remote monitoring and operation at the Colorado River Irrigation District -- Web-based GIS decision support system for irrigation districts -- Using RiverWare as a real time river systems management tool -- Submerged venturi flume -- Ochoco Irrigation District telemetry case study -- Uinta Basin Replacement Project: a SCADA case study in managing multiple interests and adapting to loss of storage -- Training SCADA operators with real-time simulation -- Demonstration of gate control with SCADA system in Lower Rio Grande Valley, in Texas -- Incorporating sharp-crested weirs into irrigation SCADA systems

    Mapping Digital Media: Poland

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    The Mapping Digital Media project examines the global opportunities and risks created by the transition from traditional to digital media. Covering 60 countries, the project examines how these changes affect the core democratic service that any media system should provide: news about political, economic, and social affairs.Digital switch-over of terrestrial broadcasting in Poland may still be almost a year away, but the lead-up and preparations to it have shed light on the most entrenched problems facing the country's public service broadcasters.This study of the impact of digitization on Polish media highlights the delays in digitization caused by political infighting; the lack of technical and financial assistance to ensure that the most vulnerable members of society benefit from digitization and new media; and the funding crisis afflicting public broadcasting. The political and economic position of the public broadcaster is critical in the digitization of broadcasting in Poland, both because of its continued—albeit diminishing—role in the media market, and because of its extensive involvement in the preparations for the switch-over.The authors of this report assess that the initiatives to inform the public about how digitization will affect them have been insufficient. Appropriate provisions should swiftly be put in place. Other major recommendations include a revision of spectrum allocation criteria to improve access for those "third way" broadcasters such as religious, educational, civil society or local government outlets, and the need for a durable solution to the public broadcasting funding crisis
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