7 research outputs found

    An Iterative Detection Aided Unequal Error Protection Wavelet Video Scheme Using Irregular Convolutional Codes

    No full text
    A wavelet-based videophone scheme proposed, where the video bits are Unequal Error Protection (UEP) using Irregular Convolutional Codes (IRCCs). The proposed system uses Adaptive Arithmetic Coding (AAC) for encoding the motion vectors and individual wavelet subband coefficients. The turbo equalized IRCC-aided videophone scheme is capable of attaining a near unimpaired video quality for channel Signal-to-Noise Ratios (SNRs) in excess of about 4.5dB over a five-path dispersive AWGN channel

    Wavelet based design of digital multichannel communications systems

    Get PDF
    The huge penetration of the personal communications systems in the market is constantly presenting new challenges to the research, aimed at satisfying people's needs and requirements for effective communication systems. At present, the cellular telephone network is perhaps the most evident example of communication system that has had a great impact on the lives of ordinary people and, at the same time, is the subject of interest of many researchers both at academic and industrial level. For the future, one of the main challenges in telecommunications will be the provision of ubiquitous broadband tetherless integrated services to mobile users. Such a pretentious goal cannot be achieved without a continuous research facing such problems as service quality, complete mobility support, and affordable complexity that are still open problems. However, present telecommunication problems are not only a matter of implementation or development of new services, exploiting a totally assessed doctrine. In order to respond to the mobility of the users personal communication systems have to deal with the wireless communication channel whereby mobility and non-stationarity of the propagation conditions require a stochastic description of the channel parameters. While this fact can be viewed as strong limitation to the development of a solid theory whose validity can be assesed in practice, on the other hand allows for an investigation and study of novel communication schemes, sometimes encompassing basic aspects of digital communications. This thesis, is the result of a research work that has investigated one of the basic building block of every communication systems, the modulation scheme, and the design of the pulse shape carrying the digital information. We have studied the design of multichannel communication scheme exploiting the mathematical theory of wavelets. Such a theory, developed recently, has had a great impact in many fields of engineering and of other scientific disciplines. In particular, wavelet theory has become very popular in the signal processing area; in fact it is a flexible toolbox for signal analysis allowing effective representation of signals for features extraction purposes. The main features that make wavelet waveforms suitable to be used as shaping pulses for modulation are their substantial compact support both in the time and frequency domains, and the fact that they are ISI-free pulses over frequency flat channels. The study presented in this thesis is focused on application of wavelet theory to design high-efficiency multichannel communication schemes and to the performance evaluation over linear and non-linear channels. We present a general method to design wavelet based multichannel communication schemes that we denoted Wavelet Orthogonal Frequency Division Multiplexing (WOFDM). We show that such schemes, having a largerspectral efficiency for a small number of channels, are a valid alternative to the classical OFDM. Potential advantage of wavelet modulation are shown presenting other applications examined in this thesis: a joint use of WOFDM and Trellis Coded Modulation to shape the power spectrum in order to match a frequency selective channel and minimize distortion, and application to spread spectrum modulation. Particular attention has been devoted to the timing recovery problem in multichannel communication schemes, exploiting the timing information of the different subchannels to improve the error variance in estimation of the sampling instant leading to a reduction of the adjacent channels interferenc

    Improving Hybrid Brainstorming Outcomes with Scripting and Group Awareness Support

    Get PDF
    Previous research has shown that hybrid brainstorming, which combines individual and group methods, generates more ideas than either approach alone. However, the quality of these ideas remains similar across different methods. This study, guided by the dual-pathway to creativity model, tested two computer-supported scaffolds – scripting and group awareness support – for enhancing idea quality in hybrid brainstorming. 94 higher education students,grouped into triads, were tasked with generating ideas in three conditions. The Control condition used standard hybrid brainstorming without extra support. In the Experimental 1 condition, students received scripting support during individual brainstorming, and students in the Experimental 2 condition were provided with group awareness support during the group phase in addition. While the quantity of ideas was similar across all conditions, the Experimental 2 condition produced ideas of higher quality, and the Experimental 1 condition also showed improved idea quality in the individual phase compared to the Control condition

    Emerging Trends in and Strategies for Industry 4.0 During and Beyond Covid-19

    Get PDF
    “Emerging Trends in and Strategies for Industry 4.0 During and Beyond Covid-19” is an all-encompassing scholarly referenced book which is comprised of original and previously unpublished research articles and chapters that would provide cutting-edge, multidisciplinary research and expert insights on advancing technologies and new strategies being used in businesses settings as well as for administrative and leadership roles in organizations during and beyond Covid-19 in perspective of Industry 4.0. The goal of this volume is to provide an overview of how Covid-19 businesses settings as well as for administrative and leadership roles in organizations studies. The Covid-19 outbreak has given an unprecedented shock to the global economy. It has also laid bare the vulnerabilities of many practices that had overtime become defining and sacrosanct features of our economic systems. In particular, business management and administrative have come under scrutiny as different production facilities are closed down, demand patterns shifted, and mobility of goods came to a virtual halt. Concerns have been noted about overreliance on firms to meet even the most basics of our needs. Disruptions caused by the Covid-19 outbreak to supply needs of customers have inflicted immense hardships upon firms and communities globally. It is incumbent upon management scholars to reflect upon this distressful situation, develop knowledge and devise strategies to help overcome the crisis. The world was already moving towards industry 4.0, but the global pandemic of Covid-19 has really rushed the things up. In different aspects of life in general and business in particular, optimized computerization, digitalization and artificial intelligence are being used with never seen- before speed and impact. It has brought with it unique challenges and opportunities. This book looks into the challenges and business opportunities in industry 4.0, trends it is setting, and research and strategies for its successful implementation. Covering a wide range of topics including community engagement, human resource management, data management, economy, R&D, communication, agile production, organizational behaviours and mobile learning, this publication provides insights into technological advancements with business administrative applications and examines forthcoming implementation strategies

    Preface

    Get PDF

    SIMULATING SEISMIC WAVE PROPAGATION IN TWO-DIMENSIONAL MEDIA USING DISCONTINUOUS SPECTRAL ELEMENT METHODS

    Get PDF
    We introduce a discontinuous spectral element method for simulating seismic wave in 2- dimensional elastic media. The methods combine the flexibility of a discontinuous finite element method with the accuracy of a spectral method. The elastodynamic equations are discretized using high-degree of Lagrange interpolants and integration over an element is accomplished based upon the Gauss-Lobatto-Legendre integration rule. This combination of discretization and integration results in a diagonal mass matrix and the use of discontinuous finite element method makes the calculation can be done locally in each element. Thus, the algorithm is simplified drastically. We validated the results of one-dimensional problem by comparing them with finite-difference time-domain method and exact solution. The comparisons show excellent agreement
    corecore