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Wyniki wyszukiwania dla: wireless power transfer
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Open extensive IoT research and measurement infrastructure for remote collection and automatic analysis of environmental data.
PublikacjaInternet of Things devices that send small amounts of data do not need high bit rates as it is the range that is more crucial for them. The use of popular, unlicensed 2.4 GHz and 5 GHz bands is fairly legally enforced (transmission power above power limits cannot be increased). In addition, waves of this length are very diffiult to propagate under field conditions (e.g. in urban areas). The market response to these needs are the...
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Communication Networks in the Service of the Environmental Monitoring
PublikacjaIn the paper selected issues relating to communication networks in the services of the environmental monitoring (EM) have been described. It is divided into three main parts: introduction, wire and wireless networks. At the beginning of the basic definitions were explained. The wire part focuses on a plain old telephone service (POTS), an integrated services digital network (ISDN), a digital subscriber line (DSL) and a fiber-optic...
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Karhunen-Loeve-based approach to tracking of rapidly fading wireless communication channels
PublikacjaWhen parameters of wireless communication channels vary at a fast rate, simple estimation algorithms, such as weighted least squares (WLS) or least mean squares (LMS) algorithms, cannot estimate them with the accuracy needed to secure the reliable operation of the underlying communication systems. In cases like this, the local basis function (LBF) estimation technique can be used instead, significantly increasing the achievable...
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Wireless Local Area Network Technologies as Communication Solutions for Unmanned Surface Vehicles
PublikacjaAs the number of research activities and practical deployments of unmanned vehicles has shown a rapid growth, topics related to their communication with operator and external infrastructure became of high importance. As a result a trend of employing IP communication for this purpose is emerging and can be expected to bring significant advantages. However, its employment can be expected to be most effective using broadband communication...
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Evaluation of Selected Modulation Techniques in Underwater Multipath Channel
PublikacjaThere is a growing interest in the use of Autonomous Underwater Vehicles (AUVs) and Underwater Sensor Networks (USNs) for scientific, military, and industrial applications, leading to the development of wireless underwater communications. However, the channel for Underwater Acoustic (UWA) communications is challenging compared to the radio wave propagation in the air. Especially in shallow waters, where the channel has strong multipath...
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ESPAR Antenna-Based WSN Node With DoA Estimation Capability
PublikacjaIn this paper, we present a low-cost energy-efficient electronically steerable parasitic array radiator (ESPAR) antenna-based wireless sensor network (WSN) node designed for IEEE 802.15.4 standard that is capable of performing direction of arrival (DoA) estimation in real-life outdoor environments. To this end, we propose the WSN node architecture, design and realization that utilizes NXP JN5168 radio frequency (RF) wireless transceiver...
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Vision-based parking lot occupancy evaluation system using 2D separable discrete wavelet transform
PublikacjaA simple system for rough estimation of the occupancy of an ad-hoc organized parking lot is presented. A reasonably simple microprocessor hardware with a low resolution monochrome video camera observing the parking lot from the location high above the parking surface is capable of running the proposed 2-D separable discrete wavelet transform (DWT)-based algorithm, reporting the percentage of the observed parking area occupied by...
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Sieć sensorowa do rejestracji drgań górnej sieci trakcyjnej w celach diagnostyki eksploatacyjnej
PublikacjaWraz ze wzrostem prędkości kolejowych pojazdów elektrycznych zwiększają się wymagania utrzymania sieci trakcyjnej w odpowiednim stanie technicznym. Ciągły monitoring i diagnostyka pozwalają wykrywać pogarszającą się jakość odbioru prądu z sieci jezdnej. Jedną z metod jest umieszczenie czujników przyspieszenia na przewodzie jezdnym. Analiza przebiegu przyspieszenia pozwala określić jakość współpracy sieci jezdnej z pantografem....
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On the fast BSS transition algorithms in the IEEE 802.11r local area wireless networks
PublikacjaHandover performance is critical to support multimedia services that are becoming increasingly available over the wireless devices. The high transition delay can be unaccepted for such services or can be a source of disruption on the session. On the other side, IEEE 802.11 standard is being extended with new functionalities. Security and QoS features, included in recent IEEE 802.11-2007 standard, add management frames that are...
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Guessing Intrinsic Forwarding Trustworthiness of Wireless Ad Hoc Network Nodes
PublikacjaA novel node misbehavior detection system called GIFTED is proposed for a multihop wireless ad hoc network (WAHN) whose nodes may selfishly refuse to forward transit packets. The system guesses the nodes’ intrinsic forwarding trustworthiness (IFT) by analyzing end-to-end path performance rather than utilizing unreliable and incentive incompatible low-layer mechanisms. It can work with occasional IFT jumps, directional antennae,...
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Testbed analysis of video and VoIP transsmission performance in IEEE 802.11 b/g/n networks
PublikacjaThe aim of the work is to analyze capabilities and limitations of different implementations of IEEE 802.11 technologies (IEEE 802.11 b/g/n), utilized for both video streaming and VoIP calls directed to mobile devices. Our preliminary research showed that results obtained with currently popular simulation tools can be drastically different than these possible in real-world environment, so, in order to correctly evaluate performance...
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Novel Adaptive Method for Data Streams Allocation Based on the Estimate of Radio Channel Parameters in Heterogeneous WBAN Network
PublikacjaThe new adaptive method for data streams allocation in heterogeneous Wireless Body Area Networks and meas-urement equipment is presented. The results obtained using the developed method compared with the selected algorithms likely to be used in those networks. The pro-posed adaptive data streams allocation method based on radio channel parameters makes it even twice as efficient to use in terms of resources usage in a WBAN heterogeneous...
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Influence of ESPAR antenna radiation patterns shape on PPCC-based DoA estimation accuracy
PublikacjaIn the article, we show the influence of three different electronically steerable parasitic array radiator (ESPAR) antenna radiation patterns on the overall direction of arrival (DoA) estimation accuracy when power-pattern cross-correlation (PPCC) algorithm, relying on received signal strength (RSS) values, is used for the estimation. The ESPAR antenna designs were obtained for three optimization goals, which resulted in different...
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Energy Efficiency Study of Audio-video Content Consumption on Selected Android Mobile Terminals
PublikacjaMobile devices are widely used by billions of users worldwide. Thanks to their main advantage, which is portability, they should be fully operational as long as possible, without the need to recharge or connect them to external power sources. This paper describes a study, carried out on four different mobile devices, with different hardware and software parameters, running the Android operating system. The research campaign involved...
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Distributed protection against non-cooperative node behavior in multi-hop wireless networks
PublikacjaAn important security problem in today's distributed data networks is the prevention of non-cooperative behavior i.e., attacks consisting in the modification of standard node operation to gain unfair advantage over other system nodes. Such a behavior is currently feasible in many types of computer networks whose communication protocols are designed to maximize the network performance assuming full node cooperation. Moreover, it...
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MEASUREMENT AND ANALYSIS OF ELECTRIC FIELD INTENSITY NEAR SELECTED TRANSMITTERS OF MOBILE TELEPHONY BASE STATIONS
PublikacjaWireless connectivity has become increasingly common in recent times. Day by day, there are more radiocommunication devices and new ideas for them. In the near future, when the fifth generation networks will be implemented, whose main feature will be continuous wireless communication, we must approach the issue of electric field measurements more and more carefully.
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HCI-Based Wireless System for Measuring the Concentration of Mining Machinery and Equipment Operators
PublikacjaMaintaining stable and reliable working conditions is a matter of vital importance for various companies, especially those involving heavy machinery. Due to human exhaustion, as well as unpredicted hazards and dangerous situations, the personnel has to take actions and wisely plan each move. This paper presents a human–computer interaction (HCI)-based system that uses a concentration level measurement function to increase the safety...
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Mitigating Traffic Remapping Attacks in Autonomous Multi-hop Wireless Networks
PublikacjaMultihop wireless networks with autonomous nodes are susceptible to selfish traffic remapping attacks (TRAs). Nodes launching TRAs leverage the underlying channel access function to receive an unduly high Quality of Service (QoS) for packet flows traversing source-to-destination routes. TRAs are easy to execute, impossible to prevent, difficult to detect, and harmful to the QoS of honest nodes. Recognizing the need for providing...
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Accurate PPCC-Based DoA Estimation Using Multiple Calibration Planes for WSN Nodes Equipped with ESPAR Antennas
PublikacjaIn this paper, we have introduced a new direction-of-arrival (DoA) estimation method, which relies on received signal strength (RSS) values measured at the output port of electronically steerable parasitic array radiator (ESPAR) antenna and uses the power pattern cross-correlation (PPCC) estimator. In the method, we have successfully incorporated measurements of ESPAR antenna's radiation patterns performed at multiple calibration...
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Pompownie dużej mocy z falownikiem wędrującym średniego napięcia
PublikacjaArtykuł zawiera rys rozwoju napędów przekształtnikowych w stacjach pomp, w szczególności regulacji wydatku kilku pomp, po kolei, przez jeden przemiennik częstotliwości. Omówiono podstawy teoretyczne zjawiska pola niestłumionego i napięcia resztkowego silników, które utrudniają szybkie przełączania silnika pompy pomiędzy zasilaniem regulowanym przez falownik a zasilaniem z sieci. Przedstawiono zasady transferu (przełączania) synchronicznego...
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Nonradiative long range energy transfer in donor-acceptor systems with excluded volume
PublikacjaW pracy analizowano bezpromienisty długozasięgowy transfer energii w układach donor-akceptor z uwzględnieniem objętości wyłączonej. Stwierdzono, że zanik fluorescencji pierwotnie wzbudzonych donorów jest wolniejszy, jeżeli uwzględnia się objętość wyłączoną. Ten efekt jest znacznie wzmocniony, gdy akceptory znajdują się w pewnej objętości niedostępnej dla donorów. Analizę numeryczną przeprowadzono stosując metodę symulacji Monte...
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Performance Analysis of Multicast Video Streaming in IEEE 802.11 b/g/n Testbed Environment
PublikacjaThe aim of the work is to analyse capabilities and limitations of different IEEE 802.11 technologies (IEEE 802.11 b/g/n), utilized for both multicast and unicast video streaming transmissions directed to mobile devices. Our preliminary research showed that results obtained with currently popular simulation tools can be drastically different than these possible in real-world environment, so, in order to correctly evaluate performance...
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Design and Performance Evaluation of the Energy Subsystem of a Hybrid Light andWave Energy Harvester
PublikacjaThe paper presents the design and performance of an energy subsystem (ES) dedicated to hybrid energy harvesters (HEHs): wave energy converters (WECs) combined with photovoltaic panels (PVPs). The considered ES is intended for compact HEHs powering autonomous end-node devices in distributed IoT networks. The designed ES was tested experimentally and evaluated in relation to the mobile and wireless distributed communication use case....
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RSS-Based DoA Estimation Using ESPAR Antenna Radiation Patterns Spline Interpolation
PublikacjaIn this paper, it is shown how power pattern crosscorrelation (PPCC) algorithm, which relies on received signal strength (RSS) values recorded at electronically steerable parasitic array radiator (ESPAR) antenna output port, used for direction-of-arrival (DoA) estimation, can easily be improved by applying spline interpolation to radiation patterns recorded in the calibration phase of the DoA estimation process. The proposed method...
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A novel calibration method for RSS-based DoA estimation using ESPAR antennas
PublikacjaIn this paper, we introduce a new calibration method that can successfully be used in direction of arrival (DoA) estimation using electronically steerable parasitic array radiator (ESPAR) antennas and employing power-pattern cross-correlation (PPCC) algorithm, which relies on received signal strength (RSS) values recorded at the antenna output port. Instead of the commonly used two-step approach, during which ESPAR antenna calibration...
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Wireless Link Selection Methods for Maritime Communication Access Networks—A Deep Learning Approach
PublikacjaIn recent years, we have been witnessing a growing interest in the subject of communication at sea. One of the promising solutions to enable widespread access to data transmission capabilities in coastal waters is the possibility of employing an on-shore wireless access infrastructure. However, such an infrastructure is a heterogeneous one, managed by many independent operators and utilizing a number of different communication...
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User Orientation Detection in Relation to Antenna Geometry in Ultra-Wideband Wireless Body Area Networks Using Deep Learning
PublikacjaIn this paper, the issue of detecting a user’s position in relation to the antenna geometry in ultra-wideband (UWB) off-body wireless body area network (WBAN) communication using deep learning methods is presented. To measure the impulse response of the channel, a measurement stand consisting of EVB1000 devices and DW1000 radio modules was developed and indoor static measurement scenarios were performed. It was proven that for...
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A family of new generation miniaturized impedance analyzers for technical object diagnostics
PublikacjaThe paper presents the family of three analyzers allowing to measure impedance in range of 10 ohm<|Zx|<10 Gohm in a wide frequency range from 10 mHz up to 100 kHz. The most important features of the analyzers family are: miniaturization, low power consumption, low production cost, telemetric controlling and the use of impedance measurement method based on digital signal processing DSP. The miniaturization and other above mentioned...
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Simultaneous handover scheme for IEEE 802.11 WLANs with IEEE 802.21 tiggers
PublikacjaHandover performance in wireless networks is important, especially nowadays, when multimedia services are becoming increasingly available over the wireless devices. However, users expect uncompromised mobility when using the service. Thus, the support of multimedia services is not possible if handover is inefficient. At the same time it is clear that a strict separation between IP Layer and the Link Layer results in built-in sources...
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Miniaturized and Lightweight ESPAR Antenna for WSN and IoT Applications
PublikacjaA new compact ESPAR antenna is investigated in this paper. The proposed antenna has 12 directional radiation patterns based on 12 passive elements and can be successfully used in Wireless Sensor Network applications. In proposed antenna design, the possibilities of 3D printing were used to implement a dielectric miniaturization overlay that allowed for reducing antenna occupied area by almost 60% and antenna profile by 27% in comparison...
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Zaawansowany układ samoczynnego załączania rezerwy oparty na sterowniku WAGO PFC200
PublikacjaArtykuł opisuje projekt i wykonanie układu samoczynnego załączania rezerwy (SZR) na potrzeby stacji elektroenergetycznej Laboratorium LINTE^2 na Politechnice Gdańskiej. Układ SZR został zbudowany na podstawie modułowego sterownika PLC WAGO PFC200. W artykule omówiono zasadę działania układu, a także jego program sterowania i aplikację panelu HMI, opracowane w zintegrowanym środowisku programistycznym CoDeSys 3.5. Oprócz zadań typowego...
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Validation of a virtual test environment for C2X communication under radio jamming conditions
PublikacjaIn this paper, we propose a novel car-2-x communication security testing methodology in the physical layer of wireless systems. The approach is dedicated to automated testing of autonomous vehicles and it is essential for such complex systems operation, especially with regard to safety and security issues. It is based on scenario-driven testing in virtual and real test environments created from collected or simulated data. The...
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Wirelessly Interfacing Objects and Subjects of Healthcare System – IoT Approach
PublikacjaWireless sensor networks, WSN, for which development has begun by military applications, are nowadays applied to all human activities; e.g. in medicine for patience monitoring or to reduce the effects of disasters. Therefore, the WSNs area has been also one of the emerging and fast growing scientific fields. Increasing interest of WSNs is even caused by equally intense growth of interest in the Internet of Things domain, IoT, in...
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Reconfigurable Antennas for Trustable Things
PublikacjaIn modern applications, the Internet of Things plays a significant role in increasing the productivity, effectiveness or safety and security of people and assets. Additionally, the reliability of Internet of Things components is crucial from the application point of view, where a resilient and low-latency network is needed. This can be achieved by utilizing reconfigurable antennas to enhance the capabilities of the wireless sensor...
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Analiza sterowania ułamkowego PIλDμ mocą reaktora jądrowego
PublikacjaW artykule przedstawiono syntezę regulatora PIλDμ niecałkowitego rzędu dla potrzeb sterowania mocą reaktora jądrowego lekko wodnego określanego, jako typu PWR (Pressurized Water Reactor). W tym celu wykorzystano nieliniowy model matematyczny reaktora PWR o parametrach skupionych obejmujący procesy generacji i wymiany ciepła oraz termicznych efektów reaktywnościowych. Nastawy regulatora PIλDμ niecałkowitego rzędu dobrano w sposób...
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Dynamic Route Discovery Using Modified Grasshopper Optimization Algorithm in Wireless Ad-Hoc Visible Light Communication Network
PublikacjaIn recent times, visible light communication is an emerging technology that supports high speed data communication for wireless communication systems. However, the performance of the visible light communication system is impaired by inter symbol interference, the time dispersive nature of the channel, and nonlinear features of the light emitting diode that significantly reduces the bit error rate performance. To address these problems,...
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Technological substitution in Asia
PublikacjaThis book provides extensive evidence on information and communication technologies development diffusion patterns, unveils specific ‘network effects’ that enhance rapid spread of ICT, and detect major macroeconomic determinants of this process, across 36 Asian economies over the period 1980-2015. Moreover, this research traces country-specific patterns of the unique process. We consider two types of technological substitution,...
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Near-Field Wireless Sensing of Plastics and Papers Using Frugal Peel-Off Passive Tag
PublikacjaThis article presents a novel frugal approach of testing plastics and papers using a near-field microwave sensing technique with a peel-off tag. The proposed sensing technique involves two electrical entities: the sensor, which may be regarded as a reader, and a disposable tag. The reader is a modified design of a gap-coupled microstrip line (GCML) sensor, while the passive tag is a standard double-ring complementary split-ring...
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Wielopoziomowy przekształtnik trakcyjny SiC z izolacją od sieci 3kV DC realizowaną za pomocą transformatorów 30kHz do napędów EZT
PublikacjaW referacie przedstawiono wielopoziomowy izolowany kaskadowy przekształtnik DC-AC z tranzystorami SiC MOSFET 1,2kV, przeznaczony do napędów elektrycznych zespołów trakcyjnych (EZT). Zaproponowana konstrukcja przekształtnika, przeznaczonego do pracy przy zasilaniu z sieci trakcyjnej 3kV DC, spełnia założenia energoelektronicznego transformatora trakcyjnego (z ang. Power Electronic Traction Transformer). Budowa modułowa z niskonapięciowych...
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Enhancing Resilience of FSO Networks to Adverse Weather Conditions
PublikacjaOptical wireless networks realized by means of gigabit optical wireless communication (OWC) systems are becoming, in a variety of applications, an important alternative, or a complementary solution, to their fiber-based counterparts. However, performance of the OWC systems can be considerably degraded in periods of unfavorable weather conditions, such as heavy fog, which temporarily reduce the effective capacity of the network....
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Testing OFDM Transmission Schemes for Shallow Water Acoustic Communications
PublikacjaLarge variability of communication properties of underwater acoustic channels, and especially strongly varying instantaneous conditions in shallow waters, is a tough challenge for the designers of underwater acoustics communication (UAC system. There is a need for developing adaptive signaling schemes that would dynamically optimize signal parameters in both physical and link layers of communication protocols. The orthogonal frequency...
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ReFlexeNN - the Wearable EMG Interface with Neural Network Based Gesture Classification
PublikacjaThe electromyographic activity of muscles was measured using a wireless biofeedback device. The aim of the study was to examine the possibility of creating an automatic muscle tension classifier. Several measurement series were conducted and the participant performed simple physical exercises - forcing the muscle to increase its activity accordingly to the selected scale. A small wireless device was attached to the electrodes placed...
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Overview of Metamaterials-Integrated Antennas for Beam Manipulation Applications: The Two Decades of Progress
PublikacjaMetamaterials (MMs) are synthetic composite structures with superior properties not found in naturally occurring materials. MMs have gained massive attention over the last two decades because of their extraordinary properties, such as negative permittivity and permeability. These materials enable many applications in communication subsystems, especially in the field of antenna design, to enhance gain, bandwidth, and efficiency,...
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Collision‐Aware Routing Using Multi‐Objective Seagull Optimization Algorithm for WSN‐Based IoT
PublikacjaIn recent trends, wireless sensor networks (WSNs) have become popular because of their cost, simple structure, reliability, and developments in the communication field. The Internet of Things (IoT) refers to the interconnection of everyday objects and sharing of information through the Internet. Congestion in networks leads to transmission delays and packet loss and causes wastage of time and energy on recovery. The routing protocols...
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EVALUATION OF THE USE OF M2M-TYPE NB-IoT AND LTE TECHNOLOGIES FOR MARITIME COMMUNICATION SYSTEMS
PublikacjaThe development of IoT (the Internet of Things) wireless transmission opens a new era in communication systems. In the next years, the development and implementation of IoT systems will be very dynamic. It can be seen that the solutions of LTE – NB-IoT (Long Term Evolution – Narrowband IoT) transmission devices are implemented in a wide range of terrestrial solutions, e.g. smart grids. This paper aims to analyse the possibility...
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Study on CPU and RAM Resource Consumption of Mobile Devices using Streaming Services
PublikacjaStreaming multimedia services have become very popular in recent years, due to the development of wireless networks. With the growing number of mobile devices worldwide, service providers offer dedicated applications that allow to deliver on-demand audio and video content anytime and everywhere. The aim of this study was to compare different streaming services and investigate their impact on the CPU and RAM resources, with respect...
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Bioterrorism — characteristics and possibilities of prevention
PublikacjaIn the paper bioterrorist threats have been presented. Historical background and possible methods of attacks have been described. The most dangerous pathogens and disease entities have been classified. Selected methods of detection and identification of biological weapon have been presented. The wireless system for threats monitoring — developed at Gdansk University of Technology — has been described.
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Influence of ESPAR Antenna Radiation Patterns Shape on PPCC-Based DoA Estimation Accuracy
PublikacjaIn the article, we show the influence of three different electronically steerable parasitic array radiator (ESPAR) antenna radiation patterns on the overall direction of arrival (DoA) estimation accuracy when power-pattern cross-correlation (PPCC) algorithm, relying on received signal strength (RSS) values, is used for the estimation. The ESPAR antenna designs were obtained for three optimization...
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The influence of electromagnetic pollution on living organisms – historical trends and forecasting changes
PublikacjaCurrent technologies have become a source of omnipresent electromagnetic pollution from generated electromagnetic fields and resulting electromagnetic radiation. In many cases this pollution is much stronger than any natural sources of electromagnetic fields or radiation. Wireless and radio communication, electric power transmission or devices in daily use such as smartphones, tablets and portable computers every day expose people...
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Low-Cost Automated Design of Compact Branch-Line Couplers
PublikacjaBranch-line couplers (BLCs) are important components of wireless communication systems. Conventional BLCs are often characterized by large footprints which make miniaturization an important prerequisite for their application in modern devices. State-of-the-art approaches to design of compact BLCs are largely based on the use of high-permittivity substrates and multi-layer topologies. Alternative methods involve replacement of transmission-line...