47 research outputs found

    Weyl-Heisenberg Spaces for Robust Orthogonal Frequency Division Multiplexing

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    Design of Weyl-Heisenberg sets of waveforms for robust orthogonal frequency division multiplex- ing (OFDM) has been the subject of a considerable volume of work. In this paper, a complete parameterization of orthogonal Weyl-Heisenberg sets and their corresponding biorthogonal sets is given. Several examples of Weyl-Heisenberg sets designed using this parameterization are pre- sented, which in simulations show a high potential for enabling OFDM robust to frequency offset, timing mismatch, and narrow-band interference

    Minimising fear and anxiety in working dogs:a review

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    The causes of fear and anxiety in working dogs are multifactorial and may include inherited characteristics that differ between individuals (e.g. Goddard and Beilharz, 1982; 1984a,b ), influences of the environment ( Lefebvre et al., 2007 ), and learned experiences during particular sensitive periods ( Appleby et al., 2002 ) and throughout life. Fear-related behavior compromises performance, leads to significant numbers of dogs failing to complete training (e.g., Murphy, 1995; Batt et al., 2008 ), early withdrawals from working roles ( Caron-Lormier et al., 2016 ), and can jeopardize dog and handler safety. Hence, amelioration of fear and anxiety is critical to maintain dogs in working roles and to ensure their well-being. Although current methods of selection and training are seemingly effective at producing many dogs which work in a remarkable array of environments, some dogs do not make the grade, and longevity of service is not always maximized. Programs should strive for optimal efficiency and they need to continually analyze the value of each component of their program, seek evidence for its value and explore potential evidence-based improvements. Here we discuss scientific evidence for methods and strategies which may be of value in reducing the risk of fear behaviors developing in the working dog population and suggest potentially valuable techniques and future research to explore the benefit of these approaches. The importance of environmental influences, learning opportunities, and effects of underlying temperament on the outward expression of fear and anxiety should not be underestimated. Identification of characteristics which predict resilience to stress are valuable, both to enable careful breeding for these traits and to develop predictive tests for puppies and procured animals. It is vitally important to rear animals in optimal environments and introduce them to a range of stimuli in a positive, controlled, and gradual way, as these can all help minimize the number of dogs which develop work-inhibiting fears. Future research should explore innovative methods to best measure the relative resilience of dogs to stressful events. This could include developing optimal exposure protocols to minimize the development of fear and anxiety, and exploring the influence of social learning and the most effective elements of stimulus presentation

    Parallel block signal processing in high speed wireless communication systems

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    Abstract — Block transmission systems are used for high data rate transmissions over wireless channels. The block structure can be obtained by inserting guard periods, which are used to avoid inter block interference between the transmitted data blocks. However, these guard periods produce a transmission overhead and therefore reduce the throughput of the transmission system. By using so-called overlapping techniques, a block processing structure can be realized without inserting guard periods. In this paper we will use these techniques for two major processing tasks, the data estimation and the error correction Viterbi decoding. By avoiding the overhead in terms of guard periods and initialization/termination sequences for convolutional coding, the throughput of the system can be increased significantly, while the bit error performance is only slightly decreased. Furthermore the overlapping approaches enable a block-wise parallel implementation of the receiver’s processing tasks. Depending on the used system parameters (block length, interleaving length, decoding block length), different levels of parallelization can be achieved. I
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