Institute of Electron Technology
Biblioteka Cyfrowa Instytutu Łączności / National Institute of Telecomunications: Digital LibraryNot a member yet
2189 research outputs found
Sort by
Hidden Context Influence on Pattern Recognition, Journal of Telecommunications and Information Technology, 2013, nr 1
Get PDFThe influence of hidden additional information concerning the circumstances of input data acquisition on the quality of decisions based on the data is considered. An analogue to the intuition influencing natural decision making is indicated. The problem of contextual information in decision making based on Bayes rule, on reference data sets in various applications as well as of scene analysis by numerous examples is illustrated
Performance and Limitations of VDSL2-based Next Generation Access Networks, Journal of Telecommunications and Information Technology, 2013, nr 1
Get PDFIn this paper, we first briefly review the main operational aspects of FTTC (xPON)/VDSL2 access networks. Then, we present performance measurements with respect to network sub loop operating length and VDSL2 operational profiles (8b, 12a, 17a), studying the rates that can be achieved at different scenarios. We then provide results of the effect of stationary crosstalk and non-stationary impulse noise on the provisioned service in an operating VDSL2 access network
Mobilne laboratorium badania funkcjonalności i jakości usług komunikacji elektronicznej. Telekomunikacja i Techniki Informacyjne, 2013, nr 1-2
Get PDFArtykuł opisuje projekt w ramach którego zaprojektowano mobilne laboratorium badawcze, które zostało wykonane przez Instytut Łączności we współpracy z Wojskowymi Zakładami Łączności Nr 1 w Zegrzu. Opisano zakres zastosowań i przeznaczenie takiej jednostki, funkcjonalność metrologiczną, wyposażenie w aparaturę pomiarową i możliwości eksploatacyjne. W dalszej części publikacji opisano przebieg realizacji projektu oraz uzyskane wyniki
Evaluation of the Energy Harvestable from an Airless Tire Equipped with Piezoelectric Bimorphs on the Lamellar Spokes, Journal of Telecommunications and Information Technology, 2013, nr 4
Get PDFIn this work, one evaluates the electrical power generated by an airless tire equipped with piezoelectric bimorphs on both lateral surfaces of the radially distributed lamellar spokes. Such sheet-like spokes are hinged both toward the wheel drum at the inner annular band, and toward the wheel tread at the outer annular band. Since the hinged spokes are able to transmit tension forces but unable to transmit compression forces, bending and buckling of the spokes occur in the region of contact between the tire and the road. Models for the rolling friction of the airless tire, for the bending and buckling deformation of the spokes, and for the electrical power generated by the airless tire are suggested. Variation of the curvature radii and bending deformations for the spokes in the region of contact with the road are illustrated for various values of the rolling friction coefficient and spoke length. Then, variation of the generated electrical power versus the length of contact is obtained for various travel speeds of the vehicle. One observes that the generated electrical power increases at augmentation of the rolling friction coefficient, spoke length and travel speed. Although the obtained electrical power for the proposed harvesting system is relatively modest, it is not depending on the road roughness, i.e. harvesting becomes possible even on smooth roads, such as highway surfaces
Adaptive Distributed Data Storage for Context-Aware Applications, Journal of Telecommunications and Information Technology, 2013, nr 4
Get PDFContext-aware computing is a paradigm that relies on the active use of information coming from a variety of sources, ranging from smartphones to sensors. The paradigm usually leads to storing large volumes of data that need to be processed to derive higher-level context information. The paper presents a cloud-based storage layer for managing sensitive context data. To handle the storage and aggregation of context data for context-aware applications, Clouds are perfect candidates. But a Cloud platform for context-aware computing needs to cope with several requirements: high concurrent access (all data needs to be available to potentially a large number of users), mobility support (such platform should actively use the caches on mobile devices whenever possible, but also cope with storage size limitations), real-time access guarantees – local caches should be located closer to the end-user whenever possible, and persistency (for traceability, a history of the context data should remain available). BlobSeer, a framework for Cloud data storage, is a perfect candidate for storing context data for large-scale applications. It offers capabilities such as persistency, concurrency and support for flexible storage schema requirement. On top of BlobSeer, Context Aware Framework is designed as an extension that offers context-aware data management to higher-level applications, and enables scalable high-throughput under high-concurrency. On a logical level, the most important capabilities offered by Context Aware Framework are transparency, support for mobility, real-time guarantees and support for access based on meta-information. On the physical layer, the most important capability is persistent Cloud storage
Comparison of Resource Control Systems in Multi-layer Virtual Networks, Journal of Telecommunications and Information Technology, 2013, nr 3
Get PDFThis paper describes the performance of various methods of QoS assurance for each connection in an environment composed of virtual networks and dedicate end-to-end connections inside them. The authors worked on the basis of research conducted with the use of the authorial network management system named Executed Management, which uses resources virtualization platforms VMware and Mininet for testing purposes. We briefly describe our system and techniques we used and some alternatives we tested and discarded because of their limitations. Functionality and performance of proposed solution to widespread implemented mechanisms as OpenFlow and MPLS are compared. Reasons for selecting well-known techniques to isolate networks and limit bandwidth on different levels of virtualization are considered. The purpose of this paper is to show out our studies and performance we achieved
Evaluation of Potential Dangers of Mobile Telecommunication Frequencies and Modulations, Journal of Telecommunications and Information Technology, 2013, nr 2
Get PDFMobile Telecommunication is one of the fastest growing technologies in the world. The effects of its high frequencies and complex modulations to the exposed population are considered in this paper. Experimental studies examining a variety of effects on all levels of the organism, ranging from effects on single cells to effects which manifest themselves as reactions of the entire body, there have been a number of epidemiological studies in order to establish the possible causal correlations between higher exposures to HF EMFs. Recommendations on the reduction of the effects of EMFs of Mobile Telecommunication on humans was presented
Wireless at the “Connected Games”: How the London 2012 Olympic and Paralympic Games Utilized the Latest Wi-Fi Technology, Journal of Telecommunications and Information Technology, 2013, nr 1
Get PDFThe London 2012 Olympic and Paraolympic Games drew together tens of thousands of people in the form of athletes, organisers, media, VIPs, public and many more groups and individuals. With the growth in smart phones and tablets coupled with the ever expanding volume and range of content accessed via Aps and browsers, this huge volume of people expected connectivity from their mobile devices during their time on the Olympic sites. It was BT’s role in the games as the official communications services partner to deliver Wi-Fi connectivity across the venues, covering the range of users from the public, athletes, organisers and ticket scanners. This paper examines this state of the art Wi-Fi solution
Microcomputer modelling, analysis and planning in terrestrial television broadcasting. Telekomunikacja i Techniki Informacyjne, 2013, nr 3
Get PDFThis article describes a simulation model of a national network of television broadcasting stations. The performance of a station depends on its sitting and its antenna, on its radiated power and frequency, and on surrounding terrain and electromagnetic environment. All these factors can be analysed using the simulation model. Simulation can help in the maintenance of the existing television stations and in the planning of new stations by making “what-if” considerations fast, simple and effective. The simulation model has been developed as an engineering aid in planning the low-power rebroadcasting stations
Fading Duration in Line-of-sight Radio Links at 6 GHz, Journal of Telecommunications and Information Technology, 2013, nr 2
Get PDFBroadband fixed wireless access, local multipoint distribution service networks are promising wireless solutions to connect fixed users to the backbone network instead of wired copper or fiber optic networks, via point-to-multipoint cellular networks. Channel capacity is of primary importance in broadband fixed wireless access networks due to increasing demand for multimedia services and possibility of providing wireless internet. Modern radio transmission systems are specifically designed for meeting two main objectives: to provide a solution for long distance networks with high transmission capacity, and to guarantee the highest link quality. Availability of a radio-relay system is very important and dependent on many factors, particularly propagation conditions in the troposphere. The article describes wave propagation that determines the performance of a radio-relay path at 6 GHz. Attenuation of received signal level measured in this frequency range depends on propagation condition on terrestrial path. Examples of measured fading duration of are presented