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A new approach of the digital image scene analysis is presented. In order to provide a flexible theoretical background for digital image data acquisition, image object recombining and image scene analysis, a formal system is intro...
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A new approach of the digital image scene analysis is presented. In order to provide a flexible theoretical background for digital image data acquisition, image object recombining and image scene analysis, a formal system is introduced. In order to implement a formal system in a context of digital image analysis, a formal language is also introduced. The basic idea behind it is that simple parts of complex objects can be efficiently recognized and then step by step recombined back to the complex objects. During this process of recombining, an analysis of object features and relations among them can be obtained. In order for image scene analysis become feasible, local image information should be coded in the same way as global information of an image can be reconstructed later. Digital image feature detection and object recognition can be seen as a part of scene analysis. A formalization of object classification using formal language scene analysis is given. A computer implementation of a formal system suitable for digital image analysis is presented. Simple examples of digital image scene analysis are given.
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A new stable second-order digital filter is presented. This filter section enjoys all the stability properties of wave digital filters, including forced-response stability and stability under looped conditions. Conventional stable...
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A new stable second-order digital filter is presented. This filter section enjoys all the stability properties of wave digital filters, including forced-response stability and stability under looped conditions. Conventional stable cascade and parallel realizations of digital filters using logarithmic arithmetic can freely be made by using this second-order section. This substantial advantage is achieved with only a slight extra cost. The simulation results demonstrate that the proposed second-order digital filter implemented with logarithmic arithmetic is always stable under all conditions of operation, as a simple strategy is taken into account in hardware realization.
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This paper presents FPGA implementations of two cryptanalytic attacks against DES. Linear cryptanalysis results from Matsui's (1994) work but could not be applied as such and had to be modified to face hardware constraints. We bro...
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This paper presents FPGA implementations of two cryptanalytic attacks against DES. Linear cryptanalysis results from Matsui's (1994) work but could not be applied as such and had to be modified to face hardware constraints. We broke a key in about 14 hours on one single FPGA, becoming the fastest implementation to our knowledge. In parallel, we evaluated the possibility of a cryptanalytic time-memory tradeoff using distinguished points. The original idea from Hellman (1980) has never been implemented. We performed first experimental results and designed a machine that can break a 40-bit DES in about 15 seconds, with a high success rate (72%), using one PC. An exhaustive search of the key on the same PC would have taken about 50 days.
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A general set of formulas is presented for the performance evaluation of multilevel optical networks. The reliability of the analytical model is verified by comparison with simulated results. In the mathematical approach, both the...
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A general set of formulas is presented for the performance evaluation of multilevel optical networks. The reliability of the analytical model is verified by comparison with simulated results. In the mathematical approach, both the cases of uniform and non-uniform traffic distributions are considered, the former being useful to settle the procedure and the latter, more practical, to justify the multilevel approach. Comparison with simulations is limited to the non-uniform case. Multiaccess is guaranteed by a wavelength-time division multichannel allocation (WTDMA) protocol, so that the time is subdivided in transmission cycles and each node is assigned a slot to transmit its data packet using a specific wavelength.
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Since general purpose operating systems cannot satisfy all the demands of real-time applications, they have been extended. A Windows NT extension for the operation in application of moving picture transmission on a local network i...
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Since general purpose operating systems cannot satisfy all the demands of real-time applications, they have been extended. A Windows NT extension for the operation in application of moving picture transmission on a local network is presented. In contrast to commercial extensions, an application-and scheduling-based extension has been developed. It is targeted to the network and display card. The tool developed for the evaluation of scheduling algorithms has enabled an off-line selection of a combination of scheduling algorithms. RMS and sporadic server algorithms improve functioning of the described multimedia application. The increasing of aperiodic tasks schedulability can cause a decrease of periodic tasks schedulability. By adjusting the sporadic server parameter values we determine minimal server capacity and maximal server period in order to ensure necessary aperiodic tasks schedulability, whereby periodic tasks schedulability should be disturbed as little as possible. The described adjustment procedure enables a faster and safer determination of sporadic server parameters. Carefully selected parameters have enabled further improvement concerning moving picture transmission on a local network.
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We present a new method for the discrimination of explosive cough events based on a combination of spectral and pitch-related features. The method was tested on 16 distinct partitions of a database with 9 patients. After a pre-pro...
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We present a new method for the discrimination of explosive cough events based on a combination of spectral and pitch-related features. The method was tested on 16 distinct partitions of a database with 9 patients. After a pre-processing stage where non-relevant segments were discarded, we have extracted eight features from each of the other segments and have fed them to the classifiers. Four types of algorithms were implemented to classify the events, with Bayesian classifiers achieving the best performance. Preliminary results showed that performance increased when the analysis was performed on individual subjects and when specific sensor locations were chosen. These results demonstrate that personalizing the analysis is a promising approach and shed some light on where to put sensors when automatic analysis is performed in the future.
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The paper presents the analysis and design of a distance and orientation sensor based on the triangulation principle, using three laser diodes and a position sensitive detector (PSD). A 16-bit microcontroller controls the acquisit...
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The paper presents the analysis and design of a distance and orientation sensor based on the triangulation principle, using three laser diodes and a position sensitive detector (PSD). A 16-bit microcontroller controls the acquisition and the lasers, processes the data and integrates the sensor in a distributed sensor network (DSN). A DSP based processing system gathers the multisensor data, for real-time control of a PUMA 560 robot manipulator through the DSN network. A sensor model based on theoretical and experimental results is emphasized.
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