Search results for: ADAPTIVE CONTROL - Bridge of Knowledge

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Search results for: ADAPTIVE CONTROL

Search results for: ADAPTIVE CONTROL

  • Fast Basis Function Estimators for Identification of Nonstationary Stochastic Processes

    Publication

    The problem of identification of a linear nonsta-tionary stochastic process is considered and solved using theapproach based on functional series approximation of time-varying parameter trajectories. The proposed fast basis func-tion estimators are computationally attractive and yield resultsthat are better than those provided by the local least squaresalgorithms. It is shown that two...

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  • Residue-Pole Methods for Variability Analysis of S-parameters of Microwave Devices with 3D FEM and Mesh Deformation

    This paper presents a new approach for variability analysis of microwave devices with a high dimension of uncertain parameters. The proposed technique is based on modeling an approximation of system by its poles and residues using several modeling methods, including ordinary kriging, Adaptive Polynomial Chaos (APCE), and Support Vector Machine Regression (SVM). The computational cost is compared with the traditional Monte-Carlo...

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  • Ripple oscillations in the left temporal neocortex are associated with impaired verbal episodic memory encoding

    Publication
    • Z. Waldman
    • L. Camarillo-Rodriguez
    • I. Chervenova
    • B. Berry
    • S. Shimamoto
    • B. Elahian
    • M. T. Kucewicz
    • C. Ganne
    • X. He
    • L. A. Davis... and 17 others

    - EPILEPSY & BEHAVIOR - Year 2018

    BACKGROUND: We sought to determine if ripple oscillations (80-120 Hz), detected in intracranial electroencephalogram (iEEG) recordings of patients with epilepsy, correlate with an enhancement or disruption of verbal episodic memory encoding. METHODS: We defined ripple and spike events in depth iEEG recordings during list learning in 107 patients with focal epilepsy. We used logistic regression models (LRMs) to investigate the...

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  • Medley filters - simple tools for efficient signal smoothing

    Publication

    - Year 2010

    Medley filters are defined as convex combinations of elementary smoothing filters (averaging, median) with different smoothing bandwidths. It is shown that when adaptive weights of such a mixture are evaluated using the recently proposed Bayesian rules, one obtains a tool which often outperforms the state-of-the-art wavelet-based smoothing algorithms. Additionally, unlike wavelet-based procedures, medley filters can easily cope...

  • On bidirectional preestimates and their application to identification of fast time-varying systems

    Publication

    - Year 2023

    When applied to the identification of time-varying systems, such as rapidly fading telecommunication channels, adaptive estimation algorithms built on the local basis function (LBF) principle yield excellent tracking performance but are computationally demanding. The subsequently proposed fast LBF (fLBF) algorithms, based on the preestimation principle, allow a substantial reduction in complexity without significant performance...

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  • Feature type and size selection for adaboost face detection algorithm

    Publication

    - Year 2010

    The article presents different sets of Haar-like features defined for adaptive boosting (AdaBoost) algorithm for face detection. Apart from a simple set of pixel intensity differences between horizontally or vertically neighboring rectangles, the features based on rotated rectangles are considered. Additional parameter that limits the area on which the features are calculated is also introduced. The experiments carried out on...

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  • Parallel frequency tracking with built-in performance evaluation

    The problem of estimation of instantaneous frequency of a nonstationary complex sinusoid (cisoid) buried in wideband noise is considered. The proposed approach employs a bank of adaptive notch filters, extended with a nontrivial performance assessment mechanism which automatically chooses the best performing filter in the bank. Additionally, a computationally attractive method of implementing the bank is proposed. The new structure...

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  • Modelling Object Behaviour in a Video Surveillnace System Using Pawlak's Flowgraph

    Publication

    In this paper, methodology of acquisition and processing of video streams for the purpose of modelling object behaviour is presented. Multilevel contextual video processing was also mentioned. The Pawlak’s flowgraph is used as a container for the knowledge related to the behaviour of objects in the area supervised by a video surveillance system. Spatio-temporal dependencies in transitions between cameras can be easily changed in...

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  • Generalized Savitzky–Golay filters for identification of nonstationary systems

    Publication

    The problem of identification of nonstationary systems using noncausal estimation schemes is consid-ered and a new class of identification algorithms, combining the basis functions approach with localestimationtechnique,isdescribed.Unliketheclassicalbasisfunctionestimationschemes,theproposedlocal basis function estimators are not used to obtain interval approximations of the parametertrajectory, but provide a sequence of point...

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  • RENOVATION OF ARCHIVE AUDIO RECORDINGS USING SPARSE AUTOREGRESSIVE MODELING AND BIDIRECTIONAL PROCESSING

    Publication

    The 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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  • QoS Resource Reservation Mechanisms for Switched Optical Networks

    Publication

    The paper regards the problem of resource reservation mechanisms for Quality of Service support in switched optical networks. The authors propose modifications and extensions for resources reservation strategy algorithms with resources pools, link capacity threshold and adaptive advance reservation approach. They examine proposed solutions in Automatically Switched Optical Network with Generalized Multi-Protocol Label Switching...

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  • New results on estimation bandwidth adaptation

    Publication

    The problem of identification of a nonstationary autoregressive signal using non-causal estimation schemes is considered. Noncausal estimators can be used in applications that are not time-critical, i.e., do not require real-time processing. A new adaptive estimation bandwidth selection rule based on evaluation of pseudoprediction errors is proposed, allowing one to adjust tracking characteristics of noncausal estimators to unknown...

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  • Multi-criterion decision making in distributed systems by quantum evolutionary algorithms

    Publication
    • J. Balicki
    • H. Balicka
    • J. Masiejczyk
    • A. Zacniewski

    - Year 2010

    Decision making by the AQMEA (Adaptive Quantum-based Multi-criterion Evolutionary Algorithm) has been considered for distributed computer systems. AQMEA has been extended by a chromosome representation with the registry of the smallest units of quantum information. Evolutionary computing with Q-bit chromosomes has been proofed to characterize by the enhanced population diversity than other representations, since individuals represent...

  • Local basis function estimators for identification of nonstationary systems

    Publication

    The problem of identification of a nonstationary stochastic system is considered and solved using local basis function approximation of system parameter trajectories. Unlike the classical basis function approach, which yields parameter estimates in the entire analysis interval, the proposed new identification procedure is operated in a sliding window mode and provides a sequence of point (rather than interval) estimates. It is...

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  • Diagnostyka i identyfikacja procesu przy użyciu AdMS-PCA

    Publication

    - Year 2005

    Artykuł dotyczy diagnostyki i identyfikacji procesu przy użyciu adaptacyjnego, wieloskalowego rozszerzenia PCA - Adaptive Multiscale Principal Component Analysis (AdMS-PCA). Przeprowadzona została analiza własności AdMS-PCA istotnych dla diagnostyki i identyfikacji. Zauważono wadę części adaptacyjnej metody, która ogranicza jej praktyczne zastosowanie. Zaproponowano modyfikację poprzez wprowadzenie algorytmu nadzorującego adaptację....

  • Elimination of Impulsive Disturbances From Stereo Audio Recordings Using Vector Autoregressive Modeling and Variable-order Kalman Filtering

    This paper presents a new approach to elimination of impulsive disturbances from stereo audio recordings. The proposed solution is based on vector autoregressive modeling of audio signals. Online tracking of signal model parameters is performed using the exponential ly weighted least squares algo- rithm. Detection of noise pulses an d model-based interpolation of the irrevocably distorted sampl es is realized using an adaptive, variable-order...

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  • Elimination of impulsive disturbances from stereo audio recordings

    Publication

    This paper presents a new approach to elimination of impulsive disturbances from stereo audio recordings. The proposed solution is based on vector autoregressive modeling of audio signals. On-line tracking of signal model parameters is performed using the stability-preserving Whittle-Wiggins-Robinson algorithm with exponential data weighting. Detection of noise pulses and model-based interpolation of the irrevocably distorted samples...

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  • Sonar Pulse Detection Using Chirp Rate Estimation and CFAR Algorithms

    Publication

    This paper presents a new approach to sonar pulse detection. The method uses chirp rate estimators and algorithms for the adaptive threshold, commonly used in radiolocation. The proposed approach allows detection of pulses of unknown parameters, which may be used in passive hydrolocation or jamming detection in underwater communication. Such an analysis is possible thanks to a new kind of imaging, which presents signal energy in...

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  • Worm Gear Drives with Improved Kinematic Accuracy

    Publication

    - Materials - Year 2021

    This paper presents the fundamentals of the design and applications of new worm gear drive solutions, which enable the minimisation of backlash and are characterised by higher kinematic accuracy. Different types of worm surfaces are briefly outlined. Technological problems concerning the principles of achieving a high degree of precision in machining are also described. Special attention is paid to the shaping of conical helical...

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  • Complex Root Finding Algorithm Based on Delaunay Triangulation

    A simple and flexible algorithm for finding zeros of a complex function is presented. An arbitrary-shaped search region can be considered and a very wide class of functions can be analyzed, including those containing singular points or even branch cuts. The proposed technique is based on sampling the function at nodes of a regular or a self-adaptive mesh and on the analysis of the function sign changes. As a result, a set of candidate points...

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  • Auto adaptation of mobile device characteristics to various acoustic conditions

    Publication

    The proposed methodology of auto adaptation of the mobile device characteristics to various acoustic conditions is presented in the paper. The first goal of this study was to determine the parameters of the acoustic path of the mobile device, for both transmitting (speaker) and receiver (microphone). Results of the measurement of characteristics of mobile devices were presented. Information about characteristics of individual parts...

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  • The difficult heritage. The reuse of former prison buildings

    Publication

    In recent years, there has been a trend to reuse abandoned buildings. Adaptive re-use allows preservation of the original structure and implements a new function to it. Such activity could help to preserve the historic value of buildings; moreover, many other advantages can be found in educational, ecological and economic fields. However, the question arises of whether every object can be freely adapted. This article examines the...

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  • Global Surrogate Modeling by Neural Network-Based Model Uncertainty

    Publication

    - Year 2022

    This work proposes a novel adaptive global surrogate modeling algorithm which uses two neural networks, one for prediction and the other for the model uncertainty. Specifically, the algorithm proceeds in cycles and adaptively enhances the neural network-based surrogate model by selecting the next sampling points guided by an auxiliary neural network approximation of the spatial error. The proposed algorithm is tested numerically...

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  • On optimal tracking of rapidly varying telecommunication channels

    When 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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  • A Novel Bitrate Adaptation Method for Heterogeneous Wireless Body Area Networks

    In the article, a novel bitrate adaptation method for data streams allocation in heterogeneous Wireless Body Area Networks (WBANs) is presented. The efficiency of the proposed algorithm was compared with other known algorithms of data stream allocation using computer simulation. A dedicated simulator has been developed using results of measurements in the real environment. The usage of the proposed adaptive data streams allocation...

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  • Global Complex Roots and Poles Finding Algorithm Based on Phase Analysis for Propagation and Radiation Problems

    A flexible and effective algorithm for complex roots and poles finding is presented. A wide class of analytic functions can be analyzed, and any arbitrarily shaped search region can be considered. The method is very simple and intuitive. It is based on sampling a function at the nodes of a regular mesh, and on the analysis of the function phase. As a result, a set of candidate regions is created and then the roots/poles are verified...

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  • Regularized Local Basis Function Approach to Identification of Nonstationary Processes

    The problem of identification of nonstationary stochastic processes (systems or signals) is considered and a new class of identification algorithms, combining the basis functions approach with local estimation technique, is described. Unlike the classical basis function estimation schemes, the proposed regularized local basis function estimators are not used to obtain interval approximations of the parameter trajectory, but provide...

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  • Application of sliding switching functions in backstepping based speed observer of induction machine

    The paper presents an analysis of the speed observer which is based on the backstepping and sliding mode approach. The speed observer structure is based on the extended mathematical model of an induction machine. The observer structure is based on the measured phase stator currents and transformed to ( αβ ) coordinate system. The stator voltage vector components are treated as known values. Additionally, such an observer structure...

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  • A Novel Bitrate Adaptation Method for Heterogeneous Wireless Body Area Networks

    In the article, a novel bitrate adaptation method for data streams allocation in heterogeneous Wireless Body Area Networks (WBANs) is presented. The efficiency of the proposed algorithm was compared with other known algorithms of data stream allocation using computer simulation. A dedicated simulator has been developed using results of measurements in the real environment. The usage of the proposed adaptive data streams allocation...

  • Multiple Cues-Based Robust Visual Object Tracking Method

    Publication
    • B. Khan
    • A. Jalil
    • A. Ali
    • K. Alkhaledi
    • K. Mehmood
    • K. M. Cheema
    • M. Murad
    • H. Tariq
    • A. M. El-Sherbeeny

    - Electronics - Year 2022

    Visual object tracking is still considered a challenging task in computer vision research society. The object of interest undergoes significant appearance changes because of illumination variation, deformation, motion blur, background clutter, and occlusion. Kernelized correlation filter- (KCF) based tracking schemes have shown good performance in recent years. The accuracy and robustness of these trackers can be further enhanced...

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  • A new look at the statistical identification of nonstationary systems

    Publication

    The paper presents a new, two-stage approach to identification of linear time-varying stochastic systems, based on the concepts of preestimation and postfiltering. The proposed preestimated parameter trajectories are unbiased but have large variability. Hence, to obtain reliable estimates of system parameters, the preestimated trajectories must be further filtered (postfiltered). It is shown how one can design and optimize such...

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  • Finite-window RLS algorithms

    Publication

    - SIGNAL PROCESSING - Year 2022

    Two recursive least-squares (RLS) adaptive filtering algorithms are most often used in practice, the exponential and sliding (rectangular) window RLS algorithms. This popularity is mainly due to existence of low-complexity versions of these algorithms. However, these two windows are not always the best choice for identification of fast time-varying systems, when the identification performance is most important. In this paper, we...

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  • Variable-structure algorithm for identification of quasi-periodically varying systems

    Publication

    The paper presents a variable-structure version of a generalized notchfiltering (GANF) algorithm. Generalized notch filters are used for identification of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. The proposed algorithm is a cascade of two GANF filters: a multiple-frequency "precise" filter bank, used for precise system tracking, and a...

  • Computational Simulation of the Effects of Different Culture Types and Leader Qualities on Mistake Handling and Organisational Learning

    Publication

    - Year 2023

    This chapter investigates computationally the following research hypotheses: (1) Higher flexibility and discretion in organisational culture results in better mistake management and thus better organisational learning, (2) Effective organisational learning requires a transformational leader to have both high social and formal status and consistency, and (3) Company culture and leader’s behavior must align for the best learning...

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  • Porównanie wybranych algorytmów systemu APR dla potrzeb redukcji poboru mocy cyfrowych układów CMOS

    Publication

    Praca dotyczy porównania czterech wybranych algorytmów wchodzacych w skład systemu APR (ang. Adaptive Power Reduction). Przeprowadzono weryfikację zmodyfikowanych heurystycznych algorytmów IIOI, UNILO i MAREL oraz nowego algorytmu hybrydowego (HSA) dla potrzeb syntezy wysokiego poziomu (HLS od ang. High Level Synthesis) z redukcją poboru mocy układów cyfrowych CMOS. Pozwalają one na zwiększenie poziomu redukcji mocy rozpraszanej...

  • Development and tuning of irregular divide-and-conquer applications in DAMPVM/DAC

    Publication

    - Year 2002

    This work presents implementations and tuning experiences with parallel irregular applications developed using the object oriented framework DAM-PVM/DAC. It is implemented on top of DAMPVM and provides automatic partitioning of irregular divide-and-conquer (DAC) applications at runtime and dynamic mapping to processors taking into account their speeds and even loads by other user processes. New implementations of parallel applications...

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  • Semi complex navigation with an active optical gesture sensor

    This paper presents the methods of diversified touchless interactions between a user and a mobile platform utilizing the optical gesture sensor. The sensor uses 8 photodiodes to measure the reflected light in the active mode (using embedded LEDs) or it measures shadows caused by fingers in the passive mode. Several algorithms were implemented: automatic mode switching, adaptive illumination level compensation, resolution improvements...

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  • Konzepte zur Energieeffizienzsteigerung bei Internet-Zugangsgeräten

    Publication

    - Year 2008

    The key issue of this paper is the power management of Internet access devices. The paper commences with an outline on the energy consumption of today's IT devices. It is followed by a description of options to increase energy efficiency of computers. The paper proves that in practice network cards and other IT network components, such as modems, network access points, switches and routers have the maximum energy consumption -...

  • Estimation of the Ultimate Strength of FRP Strips-to-Masonry Substrates Bond

    Publication

    - Applied Sciences-Basel - Year 2023

    Fiber-Reinforced Polymers (FRP) were developed as a new method over the past decades due to their many beneficial mechanical properties, and they are commonly applied to strengthen masonry structures. In this paper, the Artificial Neural Network (ANN), K-fold Cross-Validation (KFCV) technique, Multivariate Adaptive Regression Spline (MARS) method, and M5 Model Tree (M5MT) method were utilized to predict the ultimate strength of...

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  • Student model representation for pedagogical virtual mentors

    The paper concerns technological aspects of virtual mentors construction, especially concentrating on the student model representation. The article distinguishes several types of information that is gathered by the pedagogical agents and other educational platforms, including student knowledge model, student progress tracking, interaction process patterns and learner preferences. A set of technologies used for the student model...

  • Detection and localization of selected acoustic events in acoustic field for smart surveillance applications

    A method for automatic determination of position of chosen sound events such as speech signals and impulse sounds in 3-dimensional space is presented. The evens are localized in the presence of sound reflections employing acoustic vector sensors. Human voice and impulsive sounds are detected using adaptive detectors based on modified peak-valley difference (PVD) parameter and sound pressure level. Localization based on signals...

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  • Quality Evaluation of Novel DTD Algorithm Based on Audio Watermarking

    Publication

    Echo cancellers typically employ a doubletalk detection (DTD) algorithm in order to keep the adaptive filter from diverging in the presence of near-end speech signal or other disruptive sounds in the microphone signal. A novel doubletalk detection algorithm based on techniques similar to those used for audio signal watermarking was introduced by the authors. The application of the described DTD algorithm within acoustic echo cancellation...

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  • Detection and localization of selected acoustic events in 3D acoustic field for smart surveillance applications

    A method for automatic determination of position of chosen sound events such as speech signals and impulse sounds in 3-dimensional space is presented. The events are localized in the presence of sound reflections employing acoustic vector sensors. Human voice and impulsive sounds are detected using adaptive detectors based on modified peak-valley difference (PVD) parameter and sound pressure level. Localization based on signals...

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  • Transmission parameters of underwater communication channels

    Publication

    The 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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  • Leveraging spatio-temporal features for joint deblurring and segmentation of instruments in dental video microscopy

    Publication

    - Year 2021

    In dentistry, microscopes have become indispensable optical devices for high-quality treatment and micro-invasive surgery, especially in the field of endodontics. Recent machine vision advances enable more advanced, real-time applications including but not limited to dental video deblurring and workflow analysis through relevant metadata obtained by instrument motion trajectories. To this end, the proposed work addresses dental...

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  • Integrating modelling, simulation and data management tools to create a planning support system for the improvement of air quality by urban planning solutions

    Publication

    - Year 2023

    The urbanization pressure requires urban planners, designers, and policy makers to be more responsive to the challenges related to improving the quality of the urban environment and the living conditions of the inhabitants. One of the many environmental issues that need to be taken into account is urban air pollution. As the process of urban ventilation and air pollution dis-persion is significantly affected by the urban layout,...

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  • Direct electrical brain stimulation of human memory: lessons learnt and future perspectives

    Publication

    Modulation of cognitive functions supporting human declarative memory is one of the grand challenges of neuroscience, and of vast importance for a variety of neuropsychiatric, neurodegenerative and neurodevelopmental diseases. Despite a recent surge of successful attempts at improving performance in a range of memory tasks, the optimal approaches and parameters for memory enhancement have yet to be determined. On a more fundamental...

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  • Measurements of transmission properties of Acoustic Communication Channels

    Publication

    Tough 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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  • Highly linear CMOS triode transconductor for VHF applications

    A high-speed, fully balanced complementary-symmetry metal-oxide-semiconductor (CMOS) triode transconductor is presented. The proposed approach exploits a pseudo-differential-pair triode configuration with a simple adaptive circuit stabilising the drain-to-source voltages of metal-oxide-semiconductor (MOS) transistors. Since no additional active circuits (apart from the resistors made of the cut-off MOS devices) and no feedback...

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  • RESOURCE ALLOCATION IN DAB+ BROADCASTING SYSTEM

    With over two billion receivers operating worldwide, radio transmission is by far the most accessible medium. It has been a part of our lives since the 1920’s and has become one of the most trusted and friendly mass media. Today, its popularity is still strong, despite the outcome of many electronic media. In order to transform the radio into a viable medium of the 21st century, it will have to migrate from analogue to digital...