6,032 research outputs found
Audiomobiles, Sculptures and Conundrums
No full textRoberto Gerhard was a pioneer of electronic music in England creating a number of substantial concert, theatre and radio works from as early as 1954. Gerhard’s electronic music is one of the richest repositories for understanding the development of the composer’s late compositional technique. Apart from the Symphony no.3, ‘Collages’, none of Gerhard’s electronic music is published. This paper will discuss aspects of Gerhard’s electronic music, focusing on Audiomobiles (1958-59) and Sculptures (1963)
A Gain-Scheduling PI Control Based on Neural Networks
No full textThis paper presents a gain-scheduling design technique that relies upon neural models to approximate plant behaviour. The controller design is based on generic model control (GMC) formalisms and linearization of the neural model of the process. As a result, a PI controller action is obtained, where the gain depends on the state of the system and is adapted instantaneously on-line. The algorithm is tested on a nonisothermal continuous stirred tank reactor (CSTR), considering both single-input single-output (SISO) and multi-input multi-output (MIMO) control problems. Simulation results show that the proposed controller provides satisfactory performance during set-point changes and disturbance rejection
Roberto Gerhard’s Sound Compositions: A Historical-Philological Perspective. Archive, Process, Intent and reenactment
No full textThis research advances the current state of knowledge in the field of early tape music both empirically and methodologically. The purpose of this study is to evaluate the impact that the electronic medium exerted in the musical thinking of Roberto Gerhard, one of the most outspoken, prolific and influential composers in the Spanish diaspora whose musical legacy, for the most part unknown, is a major landmark in the early history of electroacoustic music. Gerhard’s personal tape collection, one of the largest historical archives of its kind reported in the literature, is exceptional for both its antiquity (50+-year-old tapes) and its abundance of production materials. Through the digitisation and analysis of the composer’s tape collection this research argues that the empirical study of audio documents sets out a basis for a broader understanding of textual processes. More specifically, the research demonstrates that the reconstruction of works based on magnetic tape sketches is a powerful method to advance the understanding of early tape music. This research also examines Gerhard’s sound compositions in relation to the post-war context in which they were composed. Finally, this research presents performance documentation that proposes an approach to the electroacoustic music repertoire in which creativity is not at odds with rigor and critical discernment demonstrating that archival study can be closely aligned to the concept of re-enactment
Dynamic score combination of binary experts
No full textThe combination of experts is used to improve the performance of a classification system. In this paper we propose three dynamic score combination techniques that embed the selection and the fusion approach for combining experts. The proposed techniques are designed to combine binary experts that output a score measuring the degree of similarity to the positive class. Reported results on two biometric dataset show the effectiveness of the proposed techniques in terms of AUC and EER
Dynamic Score Selection for Fusion of Multiple Biometric Matchers
No full textA biometric system for user authentication produces a matching score representing the degree of similarity of the input biometry with the set of templates for that user. If the score is greater than a prefixed threshold, then the user is accepted, otherwise the user is rejected. Typically the performance are evaluated in terms of the receiver operating characteristic (ROC) curve, and the equal error rate (EER). In order to increase the reliability of authentication through biometrics, the combination of different biometric systems is currently investigated by researchers. While a number of "fusion" algorithms have been proposed in the literature, in this paper we propose a theoretical analysis of a novel approach based on the "dynamic selection" of matching scores. Such a selector aims at choosing, for each user to be authenticated, just one of the scores produced by the different biometric systems available. We show that the "dynamic selection" of matching scores can provide a better ROC than those of individual biometric systems. Reported results on the FVC2004 dataset confirm the theoretical analysis, and show that the proposed "dynamic selection" approach is more effective when low quality scores are used
Multivariable real-time control of viscosity curve for a continuous production process of a non-Newtonian fluid
No full textThe application of a multivariable predictive controller to the mixing process for the production of a non-Newtonian fluid is discussed in this work. A data-driven model has been developed to describe the dynamic behaviour of the rheological properties of the fluid as a function of the operating conditions using experimental data collected in a pilot plant. The developed model provides a realistic process representation and it is used to test and verify the multivariable controller, which has been designed to maintain viscosity curves of the non-Newtonian fluid within a given region of the viscosity-vs-shear rate plane in presence of process disturbances occurring in the mixing process
Combination of experts by classifiers in similarity score spaces
No full textThe combination of different experts is largely used to improve the performance of a pattern recognition system. In the case of experts whose output is a similarity score, different methods had been developed. In this paper, the combination is performed by building a similarity score space made up of the scores produced by the experts, and training a classifier into it. Different techniques based on the use of classifiers trained on the similarity score space are proposed and compared. In particular, they are used in the framework of Dynamic Score Selection mechanisms, recently proposed by the authors. Reported results on two biometric datasets show the effectiveness of the proposed approac
HMMpayl: An Intrusion Detection System Based On Hidden Markov Models
No full textNowadays the security of Web applications is one of the key topics in Computer Security. Among all the solutions that have been proposed so far, the analysis of the HTTP payload at the byte level has proven to be effective as it does not require the detailed knowledge of the applications running on the Web server. The solutions proposed in the literature actually achieved good results for the detection rate, while there is still room for reducing the false positive rate.
To this end, in this paper we propose HMMPayl, an IDS where the payload is represented as a sequence of bytes, and the analysis is performed using Hidden Markov Models (HMM). The algorithm we propose for feature extraction and the joint use of HMM guarantee the same expressive power of n – gram analysis, while allowing to overcome its computational complexity. In addition, we designed HMMPayl following the Multiple Classifiers System paradigm to provide for a better classification accuracy, to increase the difficulty of evading the IDS, and to mitigate the weaknesses due to a non optimal choice of HMM parameters. Experimental results, obtained both on public and private datasets, show that the analysis performed by HMMPayl is particularly effective against the most frequent attacks toward Web applications (such as XSS and SQL-Injection). In particular, for a fixed false positive rate, HMMPayl achieves a higher detection rate respect to previously proposed approaches it has been compared with
- …
