7 research outputs found

    Fast Semivariogram Computation Using FPGA Architectures

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    The semivariogram is a statistical measure of the spatial distribution of data, and is based on Markov Random Fields (MRFs). Semivariogram analysis is a computationally intensive algorithm that has typically seen applications in the geosciences and remote sensing areas. Recently, applications in the area of medical imaging have been investigated, resulting in the need for efficient real time implementation of the algorithm. A semi-variance, Î(h), is defined as the half of the expected squared differences of pixel values between any two data locations with a lag distance of h. Due to the need to examine each pair of pixels in the image or sub-image being processed, the base algorithm complexity for an image window with n pixels is O (n2). Field Programmable Gate Arrays (FPGAs) are an attractive solution for such demanding applications due to their parallel processing capability. FPGAs also tend to operate at relatively modest clock rates measured in a few hundreds of megahertz. This thesis presents a technique for the fast computation of the semivariogram using two custom FPGA architectures. A modular architecture approach is chosen to allow for replication of processing units. This allows for high throughput due to concurrent processing of pixel pairs. The current implementation is focused on isotropic semivariogram computations only. The algorithm is benchmarked using VHDL on a Xilinx XUPV5-LX110T development Kit, which utilizes the Virtex5 FPGA. Medical image data from MRI scans are utilized for the experiments. Implementation results of the first architecture shows that a significant advantage in computational speed is attained by the architectures with respect to Matlab implementation on a personal computer with an Intel i7 multi-core processor. It is also observed that the massively pipelined architecture is nearly 100 times faster than the non-pipelined architecture

    Data Acquisition Applications

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    Data acquisition systems have numerous applications. This book has a total of 13 chapters and is divided into three sections: Industrial applications, Medical applications and Scientific experiments. The chapters are written by experts from around the world, while the targeted audience for this book includes professionals who are designers or researchers in the field of data acquisition systems. Faculty members and graduate students could also benefit from the book

    Spektrin Havainnointi Kognitiivisissa Matkaviestinlaitteissa

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    Radio spectrum is becoming a scarce resource as increasing number of wireless devices attempt to access it. As a solution to this issue, spectrum sensing based cognitive radios have been proposed. However, significant part of them are mobile, consumer-grade devices that have strict price and form-factor limitations. This works aims to address the issues related to mobile spectrum sensing by characterizing the non-idealities with a spectrum sensor prototype. Two efficient sensing algorithms and a coarse-fine controller, which aims to minimize the energy consumption and run time of an individual sensor, are implemented on an FPGA. Functionality of the implementations is verified by laboratory and field measurements. Finally, a spatial interpolation method, Kriging, is applied to the non-ideal measurement data to create a uniform radio environment map.Langattomien laitteiden yleistyminen kasvattaa radiospektrin käyttöastetta ylärajaa kohti. Ratkaisuksi ongelmaan on kehitetty spektrin havainnointiin perustuvat kognitiiviset radiot. Näistä valtaosa on kuitenkin kuluttajatason matkaviestinlaitteita, joilla on tiukat rajoitteet muun muassa hinnan ja fyysisen rakenteen suhteen. Tässä työssä perehdytään spektrin havainnoinnin haasteisiin tutkimalla havainnoinnin epäideaalisuuksia spektrisensoriprototyypillä. Työssä on toteutettu FPGA:lle kaksi energiatehokasta havainnointialgoritmia sekä karkea-herkkä -ohjain, joka pyrkii minimoimaan yksittäisen spektrisensorin energiakulutusta sekä havainnointiaikaa. Toteutettujen algoritmien toiminta ja suorituskyky verifioidaan laboratorio- sekä kenttämittauksilla. Lopuksi esitellään avaruudellinen interpolaatiomenetelmä, Kriging, jota sovelletaan epäideaaliseen kenttämittausdataan kattavan radiopeitekartan luomiseksi

    Applications and Experiences of Quality Control

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    The rich palette of topics set out in this book provides a sufficiently broad overview of the developments in the field of quality control. By providing detailed information on various aspects of quality control, this book can serve as a basis for starting interdisciplinary cooperation, which has increasingly become an integral part of scientific and applied research

    DR9.3 Final report of the JRRM and ASM activities

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    Deliverable del projecte europeu NEWCOM++This deliverable provides the final report with the summary of the activities carried out in NEWCOM++ WPR9, with a particular focus on those obtained during the last year. They address on the one hand RRM and JRRM strategies in heterogeneous scenarios and, on the other hand, spectrum management and opportunistic spectrum access to achieve an efficient spectrum usage. Main outcomes of the workpackage as well as integration indicators are also summarised.Postprint (published version

    Simulated Annealing

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    The book contains 15 chapters presenting recent contributions of top researchers working with Simulated Annealing (SA). Although it represents a small sample of the research activity on SA, the book will certainly serve as a valuable tool for researchers interested in getting involved in this multidisciplinary field. In fact, one of the salient features is that the book is highly multidisciplinary in terms of application areas since it assembles experts from the fields of Biology, Telecommunications, Geology, Electronics and Medicine

    Fast semivariogram computation using FPGA architectures

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