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    Wyświetlanie 1-13 z 13
    Tytuł:
    On a method to improve correlation properties of orthogonal polyphase spreading sequences
    Autorzy:
    Wysocki, B. J.
    Wysocki, T. A.
    Powiązania:
    https://bibliotekanauki.pl/articles/307741.pdf
    Data publikacji:
    2003
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    spread spectrum communications
    orthogonal sequences
    wireless communications
    wireless LAN
    correlation
    Opis:
    In this paper, we propose a simple but efficient method for improving correlation properties of polyphase spreading sequences for asynchronous direct sequence code division multiple access (DS CDMA) applications. The proposed method can be used to reduce the mean square value of aperiodic crosscorrelation or the mean square value of aperiodic autocorrelation, the maximum value of aperiodic crosscorrelation functions, merit factor or other properties of the sequence set. The important feature of the method is that while it modifies correlation properties of the sequence set, it preserves sequence orthogonality for perfect synchronization, if this is the property of the original sequence set.
    Źródło:
    Journal of Telecommunications and Information Technology; 2003, 2; 99-105
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Naval use cases of 5G technology
    Autorzy:
    Zmysłowski, D.
    Skokowski, P.
    Malon, K.
    Maślanka, K.
    Kelner, J. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/24201483.pdf
    Data publikacji:
    2023
    Wydawca:
    Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
    Tematy:
    wireless communications
    military communications
    5G
    technological gaps
    naval use cases
    naval task force
    coastal or harbour communications
    amphibious communications
    Opis:
    Fifth-generation (5G) technology is currently developing in mobile networks. The civilian 3rd Generation Partnership Project (3GPP) standard is the basis for this implementation. Higher throughput, network capacity, user density, and lower latency are the main advantages offered by 5G over Long Term Evolution (LTE) and older standards. For this reason, these advantages are increasingly recognized in critical mission and military solutions. However, the 5G technology utilization in military equipment requires a deep analysis of the 3GPP standard, especially regarding technological gaps, security, and use cases. This is particularly important in using communication equipment during armed conflicts. Such equipment must be characterized by greater security and reliability than civilian equipment. Currently, work and analyses in this area are realized by the European Defence Agency (EDA), North Atlantic Treaty Organization (NATO) Communications and Information Agency (NCIA), Allied Command Transformation (ACT), and NATO Science and Technology Organization (STO). In the Information Systems Technology (IST) Panel of the NATO STO, the research task group (RTG) "IST-187-RTG on 5G Technologies Application to NATO Operations" is working on this topic. This paper presents exemplary 5G use cases in the navy. We indicate potential advantages, problems, and technological gaps that should be solved before implementing 5G technology in naval systems.
    Źródło:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2023, 17, 3; 595--603
    2083-6473
    2083-6481
    Pojawia się w:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Using FDTD method to the analysis of electric field intensity inside complex building constructions
    Autorzy:
    Choroszucho, Agnieszka
    Stankiewicz, Jacek Maciej
    Powiązania:
    https://bibliotekanauki.pl/articles/378245.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
    Tematy:
    finite-difference time-domain method (FDTD)
    wireless communications
    systems
    electromagnetic wave propagation
    building materials
    Opis:
    The aim of this article is to make a detailed analysis of the influence of the reinforcement diameter, the number of rows of reinforcing bars and the spacing between them for the values of the electric field intensity. The subject of the research is a model containing a wall made of concrete (dielectric) and reinforcement (conductor). Four reinforcement systems commonly used in building construction have been analysed. In addition, the influence of symmetry and asymmetry in the structure of bars on the values of field intensity determined for non-homogeneous material structures (reinforced concrete) was considered. For comparison, a concrete wall, without reinforcement (homogeneous material) was also analysed. Using FDTD method, the maximum electric field values generated by the Wi-Fi operating at the f = 2.4 GHz were calculated.
    Źródło:
    Poznan University of Technology Academic Journals. Electrical Engineering; 2019, 97; 39-48
    1897-0737
    Pojawia się w:
    Poznan University of Technology Academic Journals. Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Integration of home digital network and Bluetooth wireless communication system
    Autorzy:
    Keller, T.
    Modelski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/309237.pdf
    Data publikacji:
    2003
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    komunikacja bezprzewodowa
    multimedia
    usługi multimedialne
    wireless communications
    multimedia systems
    multimedia services
    multimedia home platform
    digital network
    Opis:
    The paper presents new method of integration home digital network with Bluetooth wireless communication system. In this new application Bluetooth is used as one of the main ways of communication and information exchange between elements of the system for integrated, centralized control of the digital devices in the multimedia home platform. Bluetooth enables communication between multimedia gateway with the HTTP server inside and personal communication assistants (PCA), special kind of the remote control. The aim of the system is centralization of services in the multimedia gateway and integration of different services using only one control device.
    Źródło:
    Journal of Telecommunications and Information Technology; 2003, 1; 45-50
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improving the Efficiency of UAV Communication Channels in the Context of Electronic Warfare
    Autorzy:
    Semendiai, Serhii
    Tkach, Yuliіa
    Shelest, Mykhailo
    Korchenko, Oleksander
    Ziubina, Ruslana
    Veselska, Olga
    Powiązania:
    https://bibliotekanauki.pl/articles/27311946.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    cognitive radio
    software-defined radio
    neural networks
    coding
    electronic warfare
    communication channel
    wireless communications
    spectrum analysis
    Opis:
    The article is devoted to the development of a method for increasing the efficiency of communication channels of unmanned aerial vehicles (UAVs) in the conditions of electronic warfare (EW). The author analyses the threats that may be caused by the use of electronic warfare against autonomous UAVs. A review of some technologies that can be used to create original algorithms for countering electronic warfare and increasing the autonomy of UAVs on the battlefield is carried out. The structure of modern digital communication systems is considered. The requirements of unmanned aerial vehicle manufacturers for onboard electronic equipment are analyzed, and the choice of the hardware platform of the target radio system is justified. The main idea and novelty of the proposed method are highlighted. The creation of a model of a cognitive radio channel for UAVs is considered step by step. The main steps of modelling the spectral activity of electronic warfare equipment are proposed. The main criteria for choosing a free spectral range are determined. The type of neural network for use in the target cognitive radio system is substantiated. The idea of applying adaptive coding in UAV communication channels using multicomponent turbo codes in combination with neural networks, which are simultaneously used for cognitive radio, has been further developed.
    Źródło:
    International Journal of Electronics and Telecommunications; 2023, 69, 4; 727--732
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Distortion and noise problems of subcarrier multiplexed optical systems
    Autorzy:
    Udvary, E.
    Marozsák, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/309132.pdf
    Data publikacji:
    2001
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    łączność bezprzewodowa
    komunikacja bezprzewodowa
    szumy
    zakłócenia
    zniekształcenia
    wireless communications
    distortion and noise problems
    subcarrier multiplexed optical subsystems
    Opis:
    In this paper investigation of subcarrier multiplexed optical subsystems for optically supported communication systems is presented. Noise and spurious free dynamic range are the main parameters, which are determined by the applied optical transmission. The frequency dependence of these parameters and optimal frequency chosen is presented.
    Źródło:
    Journal of Telecommunications and Information Technology; 2001, 4; 60-64
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of EMF Emission Measurement Techniques to Wireless Communications Systems for Compliance With Directive 2004/40/EC
    Autorzy:
    Simunic, D.
    Gajsek, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/90092.pdf
    Data publikacji:
    2006
    Wydawca:
    Centralny Instytut Ochrony Pracy
    Tematy:
    compliance
    measurement techniques
    wireless communications systems
    Directive 2004/40/EC
    prawo
    prawo pracy
    pole elektromagnetyczne
    ocena ryzyka zawodowego
    dyrektywa 2004/40/WE
    Opis:
    Europe is the only region in the world with common legislative acts regulating exposure to electromagnetic fields (EMF) for both the general public and workers. Council Recommendation 1999/519/EC deals with the limitation of exposure of the general public to EMF (0 Hz—300 GHz). Directive 2004/40/EC regulates the minimum health and safety requirements regarding the exposure of workers to the risks arising from EMF. This paper discusses the general application of existing standards and recommendations in measurement techniques for determining compliance of measured exposure limit values and action values with those defined in 2004/40/EC.
    Źródło:
    International Journal of Occupational Safety and Ergonomics; 2006, 12, 2; 177-186
    1080-3548
    Pojawia się w:
    International Journal of Occupational Safety and Ergonomics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The influence of reinforcing steel meshes inside the concrete wall on electromagnetic field distribution
    Wpływ zbrojeniowych stalowych siatek wewnątrzbetonowych ścian na rozkład pola elektromagnetycznego
    Autorzy:
    Choroszucho, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/157263.pdf
    Data publikacji:
    2010
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    propagacja fal elektromagnetycznych
    metoda różnic skończonych (FDTD)
    komunikacja bezprzewodowa
    beton zbrojony
    electromagnetic wave propagation
    finite difference time domain method
    wireless communications
    reinforced concrete
    Opis:
    The influence of the building walls made of reinforced concrete, commonly used in construction of buildings, on the electromagnetic field distribution is presented in the paper. The analysis is connected with the relationship of the diameter of steel bars, the kind (symmetric, asymmetric) and size of the reinforcing steel mesh and the attenuation coefficient. The finite-difference time-domain method (FDTD) is used. The wall influences are analysed at frequency 2.4 GHz, as used for the Wi-Fi. The obtained results have shown that walls with the asymmetric reinforcing steel meshes cause the increase the attenuation coefficient.
    W artykule przedstawiono wpływ zbrojonych betonowych ścian na rozkład pola elektromagnetycznego oraz współczynnik tłumienia. Stosowanie nowoczesnych systemów komunikacji bezprzewodowej wymaga uwzględnienia zastosowanych materiałów o różnych właściwościach i zawierających elementy metalowe, mogących pogarszać zakładaną jakość transmisji danych. Badania związane z tym zagadnieniem dotyczą różnych konfiguracji, średnicy i rozstawu prętów oraz grubości ściany, jak i zastosowanej częstotliwości. Natomiast analizowane w tym artykule przypadki dotyczą częstotliwości 2,4 GHz (Wi-Fi) oraz powszechnie budowanych ścian z zastosowaniem zbrojonego betonu i jego typów uwzględniając: średnicę zbrojenia (d=5, d=10 mm), ilości siatek zbrojeniowych wewnątrz betonowej ściany oraz rozstaw pomiędzy stalowymi prętami (L=10, L=20 cm) (rys. 2). Dokonano porównania wpływu symetrycznego i niesymetrycznego rozstawienia siatek zbrojeniowych wewnątrz nośnej ściany o grubości 24 cm (rys. 1). Do wyznaczenia rozkładu pola elektromagnetycznego w analizowanych układach wykorzystano metodę różnic skończonych w dziedzinie czasu (ang. Finite Difference Time Domain) [1]. Jest ona szczególnie przydatna przy obliczeniach pól elektromagnetycznych zmiennych w czasie, w zakresie wielkich częstotliwości oraz sygnałów szerokopasmowych. Otrzymane rezultaty dowodzą, iż każdy rodzaj zbrojenia wpływa negatywnie na jakość transmisji danych, a nawet może powodować zaniki sygnału. W wyniku propagacji fali EM przez ścianę złożoną z dwóch stalowych siatek ustawionych niesymetrycznie względem siebie następuje wyraźny wzrost tłumienia.
    Źródło:
    Pomiary Automatyka Kontrola; 2010, R. 56, nr 2, 2; 104-106
    0032-4140
    Pojawia się w:
    Pomiary Automatyka Kontrola
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improvements of high-voltage trapezoidal waveform edge-rounding circuit
    Autorzy:
    Jankowski, Mariusz
    Powiązania:
    https://bibliotekanauki.pl/articles/397803.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
    Tematy:
    CMOS integrated circuits
    high-voltage techniques
    wireless communications
    current-mode circuits
    RFID tag
    harmonic distortion
    electromagnetic compatibility
    układy scalone CMOS
    techniki wysokonapięciowe
    komunikacja bezprzewodowa
    obwód prądowy
    zniekształcenie harmoniczne
    kompatybilność elektromagnetyczna
    Opis:
    This paper introduces a solution to a design problem caused by necessity of electromagnetic noise reduction in simple close-range wireless command and control systems, including Radio-frequency identification (RFID) systems. Trade-off between simplicity of data transmission, detection and decoding on one side vs. presence of high frequency harmonics in transmitted signals on the other makes some designers choose approach in which trapezoidal waveforms are used instead of rectangular ones. Moreover, edges of trapezoidal waveforms are additionally rounded to further limit presence of higher harmonics and thus to comply to EMI regulations and requirements. The paper proposes a solution based on a reimplementation of a high-voltage structure already proposed by the author, but implemented with use of different semiconductor technology process. Utilization of this new process and devices available in this technology makes possible significant increase of the circuit operation quality.
    Źródło:
    International Journal of Microelectronics and Computer Science; 2018, 9, 3; 93-100
    2080-8755
    2353-9607
    Pojawia się w:
    International Journal of Microelectronics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Practical Aspects of Physical and MAC Layer Security in Visible Light Communication Systems
    Autorzy:
    Blinowski, G. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/226282.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    wireless networks
    visible light communications
    wireless network security
    industrial wireless standards
    IEEE 802.15.7
    Opis:
    Visible light communication (VLC) has been recently proposed as an alternative standard to radio-based wireless networks. Originally developed as a physical media for PANs (Personal area Networks) it evolved into universal WLAN technology with a capability to transport internet suite of network and application level protocols. Because of its physical characteristics, and in line with the slogan "what you see is what you send", VLC is considered a secure communication method. In this work we focus on security aspects of VLC communication, starting from basic physical characteristics of the communication channel. We analyze the risks of signal jamming, data snooping and data modification. We also discuss MAC-level security mechanisms as defined in the IEEE 802.15.7 standard. This paper is an extension of work originally reported in Proceedings of the 13th IFAC and IEEE Conference on Programmable Devices and Embedded Systems - PDES 2015.
    Źródło:
    International Journal of Electronics and Telecommunications; 2016, 62, 1; 7-13
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation of GSM, LTE and Wi-Fi Electromagnetic Radiation in Dwellings
    Autorzy:
    Karan, Y.
    As, N.
    Şahın, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1031943.pdf
    Data publikacji:
    2017-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    wireless network adapter
    electromagnetic radiation
    electromagnetic pollution
    global system for mobile communications
    wireless fidelity
    Opis:
    Electromagnetic radiation exposure increases with the rise of the wireless communication devices. Electromagnetic radiation, especially near 2400 MHz band, has gradually increased with the widespread of wireless fidelity adapter in indoor environment. In this study, electromagnetic radiation in dwellings where different Wi-Fi adapters and routers are used was assessed by measuring the electric field and compared with other electromagnetic radiation source and the limits set by the Information and Communication Technologies Authority. Measurements were taken in the range of 760-2690 MHz bands used by GSM, 3G/LTE and Wi-Fi technologies. The detected values for all frequencies are significantly lower than the limits of the Information and Communication Technologies Authority. Among the electromagnetic radiation sources, electromagnetic radiation of Wi-Fi adapter is higher than GSM/3G/LTE sources radiation in dwellings. Electromagnetic radiation values in nearest point of high power adapter Wi-Fi antenna are close to the Information and Communication Technologies Authority limit value. Results show that electromagnetic radiation based on Wi-Fi adapters or routers can be higher than GSM based electromagnetic radiation.
    Źródło:
    Acta Physica Polonica A; 2017, 132, 3; 509-512
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Digital Audio Broadcasting or Webcasting: A Network Quality Perspective
    Autorzy:
    Gilski, P.
    Stefański, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/308048.pdf
    Data publikacji:
    2016
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    broadcast technology
    mobile communications
    quality of experience
    quality of service
    wireless communication
    Opis:
    In recent years, many alternative technologies of delivering audio content have emerged, with different advantages and disadvantages. In this paper pros and cons of digital audio broadcasting and webcasting transmission techniques in a network quality perspective are described. A case study of user expectations with respect to currently available services is analyzed, and the perceived quality of real digital broadcasted and webcasted radio stations is examined.
    Źródło:
    Journal of Telecommunications and Information Technology; 2016, 1; 9-15
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On-board Communication Challenges
    Autorzy:
    Garmann-Johnsen, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/116383.pdf
    Data publikacji:
    2009
    Wydawca:
    Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
    Tematy:
    communication
    communication at sea
    communication technology
    maritime communication
    Local Area Network (LAN)
    Wireless Local Area Network (WLAN)
    NMEA Message
    satellite communications
    Opis:
    The main objectives of the MarCom project (Maritime Communication, broadband at sea) are to investigate the main user needs and requirements to communication technologies within the maritime community. An important part of this is providing on board services to the crew, passengers and ship operations. In order to facilitate the MarCom project will propose a Generic Scalable Service Platform to handle the ‘nuts-and-bolts’ of communication. Development of this platform presents a series of challenges and considerations presented in this paper. In this paper we will indicate what challenges and possibilities this implicates for a solution for On Board LAN (Local Area Network), SOA (a WebService Oriented Architechture), and wireless communication.
    Źródło:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2009, 3, 3; 333-337
    2083-6473
    2083-6481
    Pojawia się w:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-13 z 13

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