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Search results for: SPARSE CHANNEL
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Elimination of clicks from archive speech signals using sparse autoregressive modeling
PublicationThis paper presents a new approach to elimination of impulsivedisturbances from archive speech signals. The proposedsparse autoregressive (SAR) signal representation is given ina factorized form - the model is a cascade of the so-called formantfilter and pitch filter. Such a technique has been widelyused in code-excited linear prediction (CELP) systems, as itguarantees model stability. After detection of noise pulses usinglinear...
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RENOVATION OF ARCHIVE AUDIO RECORDINGS USING SPARSE AUTOREGRESSIVE MODELING AND BIDIRECTIONAL PROCESSING
PublicationThe paper presents a new approach to elimination of broadband noise and impulsive disturbances from archive audio recordings. The proposed adaptive Kalman-like algorithm, based on a sparse autoregressive model of the audio signal, simultaneously detects noise pulses, interpolates the irrevocably distorted samples and performs signal smoothing. It is shown that bidirectional (forward-backward) processing of the archive signal improves...
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A Task-Scheduling Approach for Efficient Sparse Symmetric Matrix-Vector Multiplication on a GPU
PublicationIn this paper, a task-scheduling approach to efficiently calculating sparse symmetric matrix-vector products and designed to run on Graphics Processing Units (GPUs) is presented. The main premise is that, for many sparse symmetric matrices occurring in common applications, it is possible to obtain significant reductions in memory usage and improvements in performance when the matrix is prepared in certain ways prior to computation....
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Determination of selected parameters in a 1D open channel flow model
PublicationOkreślenie parametrów jest ważnym etapem tworzenia modelu matematycznego. W przypadku jednowymiarowego modelu przepływu ze swobodną powierzchnią opisanego układem równań de Saint-Venanta, jedną z grup parametrów wymagających identyfikacji są parametry związane z tarciem. Mogą one być określone w różny sposób, ale w większości przypadków problem ten stanowi zagadnienie żle postawione. W takich przypadkach najczęściej stosowaną...
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Aquaporin-2 water channel in the kidney of farm animals: An overview
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Omni-channel Retailing in the Fashion Industry: Its Definition and Implementation
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Laboratorial studies on the seepage impact in open-channel flow turbulence
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Multi-Channel Virtual Instrument for Measuring Temperature—A Case Study
PublicationThe article presents the hardware and software configuration of the developed multi-channel temperature measurement system as well as calibration procedures and measurement results verifying the properties of measurement channels. The system has been developed and dedicated primarily for measuring the temperature distribution in a laboratory model simulating underground power lines. With the adopted configuration of the analog...
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Assessment of the Accuracy of a Virtual Multi-Channel Temperature Measuring Instrument
PublicationThe multi-channel temperature measurement system developed works with NTC thermistors. The article presents the results of theoretical and empirical evaluation of accuracy obtained in measurement channels. The basis for the theoretical assessment is the mathematical model for each of the measurement channels and the characteristics of the system elements included in the circuits of the measurement channel. Two different methods were...
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Bandwidth Dependence of the Propagation Channel in Circular Metallic BAN Environments
PublicationIn this paper, the bandwidth dependence of the propagation channel for Body Area Networks (BANs) in circular metallic environments is addressed and models are proposed to evaluate the appropriate short-term fading margins that should be considered as a function of the system bandwidth. The deployment of BANs in metallic indoor environments, such as ships, factories, warehouses and other similar environments, involves additional...
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Zero-range potentials in multi-channel diatomic molecule scattering
PublicationZagadnienie o rozpraszaniu elektronów na molekułach rozwiązuje się w sposób jawny w modelu potencjałów o zerowym promieniu. Uwzględniając stany wzbudzone wprowadzamy potencjał macierzowy. Dla przykładu e+H_2 porównujemy wyniki obliczeń przekrojów czynnych z innymi (ab initio) oraz z doświadczeniem.
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A diplexer design method using an augmented channel filter approach
PublicationContinuous development in RFID andmicrocontrollers technologies gives new possibilities to createsystems that are able to integrate a lot of sensors based ondifferent technologies. This integration brings us closer to realizethe Ubiquitous Network Society vision. However, many problemsmust be addressed before we will benefit from such systems. Inthis paper we describe concept of integrating RFID technologywith other sensors technologies...
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PROPERTIES OF ONE DIMENSIONAL OPEN-CHANNEL STEADY FLOW EQUATIONS
PublicationIn this paper properties of discrete forms of one dimensional steady gradually varied flow equations are discussed. Such forms of flow equations are obtained as a result of approximation of their differential forms, which is required to solve them numerically. For such purpose explicit or implicit numerical approximation schemes for ordinary differential equations can be applied. It turns out that dependently on the chosen approximation...
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Analysis of radiometric signal in sedimentating suspension flow in open channel
PublicationThe article discusses issues related to the estimation of the sedimentating solid particles average flow velocity in an open channel using radiometric methods. Due to the composition of the compound, which formed water and diatomite, received data have a very weak signal to noise ratio. In the process analysis the known determining of the solid phase transportation time delay the classical cross-correlation function is the most...
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Limitations of WSSUS modeling of stationary underwater acoustic communication channel
PublicationPerformances of underwater acoustic communication (UAC) systems are strongly related to specific propagation conditions of the underwater channel. Due to their large variability, there is a need for adaptive matching of the UAC systems signaling to the transmission properties of the channel. This requires a knowledge of instantaneous channel characteristics, in terms of the specific parameters of stochastic models. The wide-sense...
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Numerical Simulation of Open Channel Flow between Bridge Piers
PublicationPrzedstawiono dwuwymiarowy model przepływu wody płytkiej, który wykorzystano do symulacji przepływu wody w kanale otwartym w rejonie przekroju mostowego. Równania przepływu rozwiązano metodą objętości skończonych. Wyniki symulacji ruchu wody pomiędzy filarami mostowymi porównano z pomiarami laboratoryjnymi przeprowadzonymi w Laboratorium Hydrauliki i Inżynierii Środowiska politechniki Gdańskiej. Zgodność uzyskanych wyników obliczeń...
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Radio Channel Measurements in Body-to-Body Communications in Different Scenarios
PublicationThis paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving...
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Radio Channel Measurements in Body-to-Body Communications in Different Scenarios
PublicationThis paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving...
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DISTRIBUTION OF FLOWS IN A CHANNEL NETWORK UNDER STEADY FLOW CONDITIONS
PublicationThe article presents an algorithm for calculating the distribution of flow in a junction of open channel network under steady flow conditions. The article presents a simplified calculation algorithm used to estimate the distribution of flow in a network of channels under steady flow conditions. The presented algorithm is based on the continuity equation and a simplified energy equation. To describe the relationship between the...
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Wideband Channel Measurements for Polarised Indoor Off-Body Communications
PublicationThis paper presents the initial results of wideband channel measurements for polarised off-body communication at 5.8 GHz, in an indoor environment. Channel Impulse Response measurements were performed simultaneously for two orthogonal polarisations of the wearable antenna, and repeated for vertical and horizontal orientations of the off-body one. Four types of measurement scenarios were considered in order to investigate the influence...
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Transmission parameters of underwater communication channels
PublicationThe underwater environment is tough and demanding as a communication channel for ultrasonic signals. The channel transmission characteristics in marine and inland waters depend much on local bathymetry and changing weather conditions. The architecture and performance of a reliable underwater acoustic communication (UAC) system should allow real-time adaptation of its transmission parameters to a large variety of possible channel...
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New aspects in assessment of changes in width of subarachnoid space with near-infrared transillumination/backscattering sounding, part 2: clinical verification in the patient
PublicationW pracy przedstawiono porównanie wyników symulacji propagacji promieniowania z zakresu bliskiej podczerwieni z danymi uzyskanymi na drodze pomiarów wykonanych w warunkach klinicznych. Różnice między nimi nie przekraczały 4 dB, co potwierdziło słuszność przyjętych założeń w procesie symulacji. W pomiarach wykorzystano unikatowy zetstaw nadajników i odbiorników promieniowania podczerwonego, pozwalającego prowadzenie pomiarów transmisji...
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Modeling of Cardiac Component of Subarachnoid Space Changes in Apnoea Resulting as a Function of Blood Pressure and Blood Flow Parameters - Two Mechanizm of Regulation
PublicationExperiments were performed in a group of 19 healthy, non-smoking volunteers. The experiment consisted of three apnoeas, sequentially: 30 s apnoea, 60 s apnoea and maximal, that could be done, apnoea. The breath-hold was separated for 5 minutes rest. The following parameters were measured and obtained for further analysis: blood parameters, artery diameter of the internal carotid artery, end-tidal CO2 in expired air, the cardiac...
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Periodicity Matters: Grating or lattice resonances in the scattering by sparse arrays of subwavelength strips and wires.
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Data fusion of sparse, heterogeneous, and mobile sensor devices using adaptive distance attention
PublicationIn environmental science, where information from sensor devices are sparse, data fusion for mapping purposes is often based on geostatistical approaches. We propose a methodology called adaptive distance attention that enables us to fuse sparse, heterogeneous, and mobile sensor devices and predict values at locations with no previous measurement. The approach allows for automatically weighting the measurements according to a priori...
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Sparse vector autoregressive modeling of audio signals and its application to the elimination of impulsive disturbances
PublicationArchive audio files are often corrupted by impulsive disturbances, such as clicks, pops and record scratches. This paper presents a new method for elimination of impulsive disturbances from stereo audio signals. The proposed approach is based on a sparse vector autoregressive signal model, made up of two components: one taking care of short-term signal correlations, and the other one taking care of long-term correlations. The method...
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Game about space or game in the space?
PublicationThe article analyzes various aspects of the actions taken by participants involved in the process of a spatial change. Such a process is described as a game about space or a game in the space. Different terminology is presented, in particular the meaning of: spatial order, regional studies, eco-development, sustainable development. Different forms of the game are analyzed: space as a theater, as a casino, as an area of conflict....
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Shaping the New Vistula Spit Channel: Political, Economic, and Environmental Aspects
PublicationIn September 2022, the new shipping channel in Poland was opened for service. It connects the Port of Elbląg and the Gdańsk Bay in Poland, cutting through the Vistula Spit and the Vistula Lagoon. It was intended to enable direct access to the Baltic Sea from the Port of Elbląg without crossing Russian territory. Originally conceptualized decades ago, it has taken its final shape only recently. Its construction was associated with...
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Channel Impulse Response Measurements at mmWave Band in Office and Conference Rooms
PublicationIn this paper, the measurements of the channel impulse response at mmWave band in office and conference rooms are described. The central frequency is 27 GHz with a bandwidth of 400 MHz. The description of the used measurement stand and considered environments are presented. The initial analysis of the power delay profile, mean delay, and RMS delay spread allows preliminary conclusions to be drawn that there is a significant impact...
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Fast multiplexer cad using surrogate models for channel filters synthesis
Publicationartykuł przedstawia metodę szybkiego projektowania multiplekserów mikrofalowych wykorzystującą dokładne modele zastępcze na etapie projektowania kanałów. przedstawiony został przykład trój-kanałowego multipleksera z filtrami dwurodzajowymi.
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Multiple-channel frequency-adaptive active vibration control using SONIC
PublicationSONIC (self-optimizing narrowband interference canceller) is an acronym of a new approach to rejection of sinusoidal disturbances acting at the output of a discretetime stable linear plant with unknown and possibly timevarying dynamics. The paper presents two frequency-adaptive extensions of the multivariate SONIC algorithm. The efficacy of the proposed solutions is tested using our laboratory-scale active vibration control plant.
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An Off-Body Channel Model for Body Area Networks in Indoor Environments
PublicationThis paper presents an off-body channel model for body area networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in a realistic indoor office environment containing typical scatterers have been measured: five were static (three standing and two...
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Stability and limit load analysis of a cold-formed channel section column
PublicationThe paper presents stability and limit load analysis of a steel column 1440 mm high of a cold-formed channel section, subjected to a combination of compression and bending. Experimental results were compared to the resistance of a code procedure and to the outcome of numerical non-linear analysis. Comparison was made of numerical solutions by means of static (Riks) and dynamic (Explicit and Implicit) methods. Perfectly elastic...
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Reduction of the Multipath Propagation Effect in a Hydroacoustic Channel Using Filtration in Cepstrum
PublicationDuring data transmission in a hydroacoustic channel, one of the problems is the multipath propagation effect, which leads to a decrease in the transmission parameters and sometimes completely prevents it. Therefore, we have attempted to develop a method, which is based on a recorded hydroacoustic signal, that allows us to recreate the original (generated) signal by eliminating the multipath effect. In our method, we use cepstral...
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Radio Channel Measurements in Off-Body Communications in a Ferry Passenger Cabin
PublicationThis paper presents an off-body radio channel measurements in a ferry passenger cabin at 2.45 GHz band, for static sleeping scenarios with different body orientation and on-body antennas placements, and also for upper and lower sleeping berths. The measurements have been performed with two types of on-body wearable receiving antennas: FlexPIFA (flexible planar inverted F antenna), and FlexNotch (flexible adhesive-backed notch antenna)...
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The effect of fishing basin construction on the behaviour of a footbrdge over the port channel
PublicationThe paper analyses possible causes of failure of the rotating footbridge over the Ustka port channel. In July, 2015, strange behaviour of this object was observed in the form of excessive vibrations of bridge platform suspension rods, with the accompanying acoustic effects. A preliminary geotechnical analysis has revealed that this destructive effect was caused by the nearby construction works, namely construction of a fishing...
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Probe signal processing for channel estimation in underwater acoustic communication system
PublicationUnderwater acoustic communication channels are characterized by a large variety of propagation conditions. Designing a reliable communication system requires knowledge of the transmission parameters of the channel, namely multipath delay spread, Doppler spread, coherence time, and coherence bandwidth. However, the possibilities of its estimation in a realtime underwater communication system are limited, mainly due to the computational...
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Measurement of Impulse Response of Shallow Water Communication Channel by Correlation Method
PublicationPerformances of underwater acoustic communication (UAC) systems are strongly related to specific propagation conditions of the underwater channel; conditions that can additionally change in time due to the movement of the acoustic system transmitter and receiver or to reflection by underwater objects of the transmitted signal. The time-varying impulse response is a comprehensive description of dynamically changing transmission...
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A navigation device utilizing body communication channel for mobile wearable systems
PublicationA novel touch sensor utilizing a body communication technology is presented in the paper. The proposed device accepts orders (gestures) only from a person wearing it. Moreover, when comparing it to a similar, however an optical one, it appears as a less power consumable. Preliminary results of its properties examination are presented and discussed. Additionally, the developed sensor allows to measure a human body the electrical...
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Investigation of Taste Substances by five Channel Lipid-Polymer Membrane Sensor.
PublicationBadano substancje o różnych stężeniach należące do czterech klas smaku za pomocą pięcio-kanałowego sensora opartego o elektrody jonoselektywne z różnymi membranami polimerowo-lipidowymi. Stwierdzono, że sensor jest czuły na zmiany stężeń chlorowodorku chininy, kawsu cytrynowego i chlorku sodu, przeciwnie jak w przypadku sacharozy. Na podstawie tych wyników można przypuszczać, że sensor może być zastosowany do roztworów składających...
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New aspects in assessment of changes in width of subarachnoid space with near-infrared transillumination/backscattering sounding, part 1: Monte Carlo numerical modeling
PublicationW pracy wykorzystano zmodyfikowaną metodę Monte Carlo do numerycznego modelowania propagacji promieniowania z zakresu bliskiej podczerwieni w warstwach anatomicznych głowy. Badano efekt zmian szerokości warstwy podpajęczynówkowej pod wpływem tętna na natężenie promieniowania wstecznie rozpraszanego. Przeprowadzone obliczenia pokazały, że możliwe jest monitorowanie zmian tej szerokości na podstawie pomiarów transmisji promieniowania...
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A note on Banach space isomorphic to Hilbert space
PublicationW pracy charakteryzuje się przestrzenie Hilberta w terminach istnienia pewnych funkcji gładkich.
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Space syntax analysis - methodology of understanding the space
PublicationNowadays space is considered as a net of connections between different areas. The questions how to delineate its character and how it is possible to objectively compare two spaces is the matter under consideration. This was the reason for creating new theories about the structure of place. "Space syntax analysis" (SSA) or simply "Space Syntax" defines a number of theories and research areas devoted to the analysis of space configuration....
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Fading modelling in dynamic off-body channels
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On optimal tracking of rapidly varying telecommunication channels
PublicationWhen parameters of mobile telecommunication channels change rapidly, classical adaptive filters, such as exponentially weighted least squares algorithms or gradient algorithms, fail to estimate them with sufficient accuracy. In cases like this, one can use identification methods based on explicit models of parameter changes such as the method of basis functions (BF). When prior knowledge about parameter changes is available the...
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Measurements of transmission properties of Acoustic Communication Channels
PublicationTough transmission properties of shallow water acoustic channels (SWAC) highly limit the use of underwater acoustic communication (UAC) systems. An adaptive matching of modulation and signaling schemes to instantaneous channel conditions is needed for reliabledata communications. This creates, however, unique challenges for designers when compared to radio transmission systems. When communication system elements are in move, the...
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A Note on Shannon Capacity for Invariant and Evolving Channels
PublicationIn the paper we discuss the notion of Shannon capacity for invariant and evolving channels. We show how this notion is involved in information theory, graph theory and Ramsey theory.
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One-Dimensional Modeling of Flows in Open Channels
PublicationIn this chapter, modeling of the unsteady open channel flow using one-dimensional approach is considered. As this question belongs to the well-known and standard problems of open channel hydraulic engineering, comprehensively presented and described in many books and publications, our attention is focused on some selected aspects only. As far as the numerical solution of the governing equations is considered, one can find out that...
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Fading Modelling in Dynamic Off-Body Channels
PublicationThis paper presents an off-body fading channel model for Body Area Networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in an indoor environment (a medium-size room with furniture, mostly consisting of wooden tables and chairs) have been measured:...
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Fading Modelling in Dynamic Off-Body Channels
PublicationThis paper presents an off-body fading channel model for Body Area Networks. The proposed model, based on both simulations and measurements at 2.45 GHz in a realistic indoor environment, consists of three components: mean path loss, body shadowing, and multipath fading. The first is modelled as a log function of distance, the path loss exponent being in between 0.4 and 1.6. A statistical perspective is taken for the other two components,...