266 research outputs found
The Haskell road to logic, maths and programming, 2nd ed. (texts in computing, vol.4)/ Doets
No full textx, 432 hal.; 23 cm
The Haskell road to logic, maths and programming, 2nd ed. (texts in computing, vol.4)/ Doets
No full textx, 432 hal.; 23 cm
Modeling Audio Fingerprints: Structure, Distortion, Capacity
No full textAn audio fingerprint is a compact low-level representation of a multimedia signal. An audio fingerprint can be used to identify audio files or fragments in a reliable way. The use of audio fingerprints for identification consists of two phases. In the enrollment phase known content is fingerprinted, and ingested into a database, together with all relevant metadata. In the identification phase, unknown audio content is fingerprinted, and the fingerprints form the query to the database. The query fingerprint is compared to the fingerprints in the database. If a similar fingerprint is found in the database, the relevant metadata corresponding to the fingerprint is returned. In this thesis we develop models for audio fingerprints. The emphasis here is on fingerprint extraction and the properties of the fingerprint, not on matching the query fingerprint to the fingerprints in the database, and the actual identification. We also do not develop new practical fingerprinting algorithms. There is a wide variety of applications for audio fingerprinting, including broadcast monitoring, audience measurement, forensic applications, blacklisting of unauthorized content, 'name that tune' services and linking of special offers to television or radio commercials. Content which uses the same recorded source material, but which is in different representation, or distorted in different ways, will generate similar audio fingerprints. This distinguishes audio fingerprints from hashes and content-based retrieval. The hash of an audio file changes when one sample changes. Two perceptually equal audio items can have completely different hash values, but will generate similar fingerprints. Content-based retrieval looks for audio items which apply to a similar concept, like the same genre, artist or style, while fingerprinting looks for the reuse of the recorded content. Of course, the exact requirements for a fingerprinting system strongly depend on the application. Relevant aspects for the topics discussed in this thesis are the robustness, uniqueness, accuracy (notably the False Acceptance Rate and False Rejection Rate), granularity and the size of the fingerprints. In this thesis we make three contributions in the form of models. First, we model the structure of a particular type of audio fingerprint, the Philips Robust Hash (PRH). The PRH fingerprint extracts a series of spectral energy related features from the audio signal, which are represented efficiently but coarsely as a binary time-series. The time-series captures the temporal and spectral dynamics of the audio signal, and has a very particular structure mainly depending on a limited number of parameters in the fingerprint extraction. The model describes the structure of the PRH as a function of a number of parameters. It can be used for better understanding and potentially optimization of the fingerprinting system. We experimentally verify the model on synthetic Gaussian iid data, and conclude that the model capture the structure of the PRH fingerprint well. This analysis was reformulated and extended by Balado, Hurley, McCarthy and Silvestre. Second, we observe that distortions in the audio are reflected in changes in the corresponding fingerprint. This kind of distortion affects the quality of the audio signal and changes the resulting fingerprint. The idea is to estimate the amount of distortion on the audio signal by comparing the corresponding fingerprint to a reference fingerprint extracted from a high quality copy of the same audio. In this way one could extend the functionality of a fingerprinting system. We implement and compare the behaviour of a number of algorithms from literature, and observe similar behaviour of the distance between corresponding fingerprints due to compression. We model the effect of particular distortions in the audio due to compression or additive white noise on the difference introduced in the PRH fingerprints. The main result of our modeling effort is a closed form relation between Signal-to-Noise Ratio (SNR) and average fingerprint distance for PRH audio fingerprints of independent identically distributed (iid) signals. We also experimentally verify the developed models. The model fits perfectly for synthetic signals, and captures the behavior observed in a wider variety of fingerprinting algorithms on actual music. Third, we consider an information theoretical framework developed by Westover and O'Sullivan (WOS). The main question is `how many signals can be identified by a fingerprinting system, under certain conditions'. The conditions relate to characteristics of the fingerprint (size of the fingerprint, and representation of the fingerprint), and characteristics of the environment in which the system operates (representation and statistical characteristics of the signals that need to be identified, how much distortion is allowed). We use the results of the model developed for the PRH fingerprint to compare to estimate up to how many signals can be identified with a binary fingerprint like the PRH. Finally, we check whether the changes in the fingerprints we observe in practice due to distortions in the audio signals, and which have been modeled in this thesis, fit in the information theoretical framework of the WOS model. We outline the differences in the WOS-model compared to practical implementations. We finish with a list of recommendations on extending the models to take jointly consider distortion and uniqueness characteristics; to take more distortion types into account, and to extend to images and video; to develop an evaluation framework for audio fingerprinting; to integrate psycho-acoustics; and to develop a theoretical framework for comparing specific algorithms to the capacity bound.MediamaticsElectrical Engineering, Mathematics and Computer Scienc
Het creëren van een healing environment: Sturen op een gastvrij zorggebouw
No full textSturen op gastvrijheid staat in veel zorginstellingen hoog op de beleidsagenda. Het creëren van een Healing Environment krijgt eveneens veel aandacht. De twee begrippen worden vaak los van elkaar toegepast. Dit artikel laat zien dat toepassing van principes uit de Healing Environment literatuur bijdraagt aan een positieve gastvrijheidsbeleving.Accepted Author ManuscriptReal Estate Managemen
Distortion Estimation in Compressed Music Using Only Audio Fingerprints
No full textAn audio fingerprint is a compact yet very robust representation of the perceptually relevant parts of an audio signal. It can be used for content-based audio identification, even when the audio is severely distorted. Audio compression changes the fingerprint slightly. We show that these small fingerprint differences due to compression can be used to estimate the signal-to-noise ratio (SNR) of the compressed audio file compared to the original. This is a useful content-based distortion estimate, when the original, uncompressed audio file is unavailable. The method uses the audio fingerprints only. For stochastic signals distorted by additive noise, an analytical expression is obtained for the average fingerprint difference as function of the SNR level. This model is based on an analysis of the Philips robust hash (PRH) algorithm. We show that for uncorrelated signals, the bit error rate (BER) is approximately inversely proportional to the square root of the SNR of the signal. This model is extended to correlated signals and music. For an experimental verification of our proposed model, we divide the field of audio fingerprinting algorithms into three categories. From each category, we select an algorithm that is representative for that category. Experiments show that the behavior predicted by the stochastic model for the PRH also holds for the two other algorithms.MediamaticsElectrical Engineering, Mathematics and Computer Scienc
The effect of islands in the Río Magdalena on discharge and sediment transport into the Canal del Dique, Colombia
No full textControlling the distribution of water and sediment at river bifurcations is one of the main challenges in river engineering and management. This distribution affects the stability of river bifurcations as well as the distribution of flooding risk, navigability and environmental conditions. The governing factors are the hydrodynamics of the two branches downstream as well as the spatial distribution of sediment transport in the area of the bifurcation. Fluvial islands at the bifurcation may affect both. This thesis focusses on the effect of size, position and shape of fluvial islands in the Río Magdalena on discharge and sediment distribution into the Canal del Dique, Colombia. Where the high amount of fine sediments in the Río Magdalena has negative environmental impact on the coastal area downstream of the Canal del Dique, therefore a solution needs to be found to reduce the high amount of sediment entering the Canal del Dique. A model study has been carried out with the use of Sobek-RE and Delft3D-FLOW in order to gain insight in the hydrodynamics and morphodynamics on a respectively one-dimensional and two-dimensional (depth-averaged) scale. It was found that size and position of the islands have an appreciable effect on the discharge and sediment in the Canal del Dique by influencing the water level at the entrance. Whereas, the shape of the islands have small influence, where protrusions and sharp edges both seem to evolve into smooth bank lines along smooth streamlines. Furthermore it was found that bathymetrical differences have an appreciable effect. However, a maximum reduction of discharge into the Canal del Dique of 8% can be obtained when the island is located just in front of the offtake. Furthermore, the amount of coarse sediment can be reduced with a factor 2.5.Environmental Fluid MechanicsHydraulic EngineeringCivil Engineering and Geoscience
Nutrition in the age-related disablement process
No full textThe transition from independence to disability in older adults is characterized by detectable changes in body composition and physical function. Epidemiologic studies have shown that weight loss, reduced caloric intake and the reduced intake of specific nutrients are associated with such changes. The mechanisms underlying these associations remain unclear, and different hypotheses have been suggested, including the reduction of the antioxidant effects of some nutrients. Changes in muscle mass and quality might play a central role in the pathway linking malnutrition, its biological and molecular consequences, and function. A different approach aims at assessing diets by dietary patterns, which capture intercorrdations of nutrients within a diet, rather than by selective foods or nutrients: epidemiologic evidence suggests that some types of diet, such as the Mediterranean diet, might prevent negative functional outcomes in older adults. However, despite a theoretical and empirical basis, intervention studies using nutritional supplementation have shown inconclusive results in preventing functional impairment and disability. The present work is the result of a review and consensus effort of a European task force on nutrition in the elderly, promoted by the International Association of Gerontology and Geriatrics (IAGG) European Region. After the critical review of different aspects related to the role of nutrition in the transition from independence to disability, we propose future lines for research, including the determination of levels of inadequacy and target doses of supplements, the study of interactions (between nutrients within a diet and with other lifestyle aspects), and the association with functional outcomes
Risk of oral and gastrointestinal mucosal injury among patients receiving selected targeted agents: a meta-analysis
No full textPurpose The purpose of this study was to estimate the risk and severity of oral and gastrointestinal mucosal toxicities associated with selected targeted agents. Methods We searched the English-language literature in February 2011 for reports of randomized clinical trials comparing a FDA-approved targeted agent to a standard of care regimens. Long-term follow-up and secondary reports of trials were excluded, leaving 85 studies for analysis. Using meta-analytic methods, we calculated the relative risks of oral and gastrointestinal toxicities, adjusting for sample size using the inverse variance technique. For each targeted agent and each side effect, we calculated the number needed to harm, the number of patients that, if treated with the more toxic regimen, would produce one additional episode of the toxicity. Results Oral mucositis was significantly more frequent among patients treated with bevacizumab, erlotinib, sorafenib, or sunitinib, although this difference was confined to low-grade mucositis. The clinical significance of these findings is unclear given its low incidence and mild severity. In contrast, diarrhea was significantly more frequent with most of the targeted agents studied, with adjusted relative risks between 1.5 and 4.5. An additional patient with diarrhea will be observed for every three to five patients treated with these targeted agents, compared with conventional regimens. Conclusions Oral mucosal toxicities occasionally complicate treatment with these targeted agents, but the clinical significance of this finding is not clear. Diarrhea is a hallmark of treatment with these targeted agents; this side effect should be carefully ascertained to permit early intervention and control
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