1869 research outputs found
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A Numerical Assessment of the Reconstruction Effectiveness of the Integrated GA-Based Multicrack Strategy
No full textThis paper is aimed at presenting a numerical study on the reconstruction accuracy (quantitative imaging) of the integrated genetic algorithm (GA)-based multicrack strategy, thus completing the assessment previously carried out and limited to verify the accuracy of the qualitative imaging (i.e., crack detection, location, and size estimation). The obtained results prove an acceptable reliability and accuracy of the GAbased integrated strategy also in reconstructing multiple defective regions even though the resulting performances degrade in comparison with those achieved by the same approach when used for qualitative imaging purposes. (c) 2007 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works
Conceptual Design and Evaluation of WIRE: A Wisdom-Aware EUD Tool
No full textThis paper presents the evaluation of the conceptual design of WIRE, a EUD tool for service-based applications. WIRE exploits community composition knowledge harvested from existing programs defined by other developers in the same domain. Such knowledge can assist less skilled developers in defining the composition they need, allowing them to go beyond their individual ca-pabilities. The assistance comes in the form of interactive contextual advices proposed during the definition of composition logic. This idea was evaluated with 10 semi-structured interviews with University accountants. A rich set of information was elicited by means of several probes, including examples of contextual helps, commercial EUD tools, and scenarios in the form of positive and negative user stories. Results informed the definition of a set of require-ments for WIRE, and fostered a critical reflection on possibilities and limita-tions of the general framework of EUD
GA-Enhanced ADS-Based Approach for Array Thinning
No full textThis study proposes a genetic algorithm (GA)-enhanced almost difference set (ADS)-based methodology to design thinned linear arrays with low-peak sidelobe levels (PSLs). The method allows one to overcome the limitations of the standard ADS approach in terms of flexibility and performances. The numerical validation, carried out in the far-field and for narrow-band signals, points out that with affordable computational efforts it is possible to design array arrangements that outperform standard ADS-based designs as well as standard GA approaches. "This paper is a postprint of a paper submitted to and accepted for publication in IET Microwaves, Antennas & Propagation and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library: http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5714040
ADS-Based Y-Shaped Arrays for Interferometry and Radio Astronomy Applications
No full textCorrelator arrays have been a topic of research since the 1960s due to their applications in the field of radio astronomy. Unlike conventional sum arrays, the data gathering efficiency of correlator arrays is related to their spatial filtering behavior. As a consequence, the design of a correlator array is essentially an optimal sampling problem in which the positions of the antennas are chosen in order to ensure optimal performances regarding all possible observation situations
Real-Time Distributed Monitoring of Electromagnetic Pollution in Urban Environment
No full textIn the last two decades, the wide diffusion of mobile phones and wireless technologies have brought many advantages in professional activities as well as in everyday life [1]‐[3]. In general, mobile telecommunication networks are constituted by a limited number of base stations (BSs) to which mobile terminals connect for data exchange. In order to provide a suitable quality of service (QoS), BSs have to be properly located such that the network coverage is uniform in the area of interest. Towards this end, the position of BSs is usually determined by taking into account the complexity of the scenario at hand through theoretical or empirical models. Unfortunately, because of the costs and the complexity of urban areas, the location of the BSs cannot be chosen in an optimal fashion. As a consequence, the spatial distribution of the radiated field turns out to be non‐uniform with variations both in time and space that can exceed the normative limits of electromagnetic emissions. In order to assess the compliance of the BS coverage to the normative limits, communications authorities usually release a test certificate after the installation. Unfortunately, because of the need of highly‐trained staff and due to the cost of the hardware measurement instrumentation, the coverage variation as well as the radiation levels are not generally monitored
Imaging Three-Dimensional Bodies by Processing Multi-Frequency Data Through a Multiscale Swarm Intelligence Based Method
No full textThis contribution is aimed at investigating the potentialities and current limitations of the multiscale particle swarm method when processing multi�]frequency data scattered by three�]dimensional structures. Such a global optimization approach demonstrated its effectiveness in solving complex two�]dimensional imaging problems. Therefore, it has been suitably�]modified for dealing with three�]dimensional geometries and integrated into multi�]frequency inversion schemes. Selected numerical results are shown in order to allow a preliminary evaluation of the reconstruction accuracy of the proposed implementations. This is the author's version of the final version available at IEEE
Synthesis and Optimization of Pre-Fractal Multiband Antennas
No full textNowadays electronic products often employ more than one wireless standards for data exchange, requiring the adoption of multi-band components and devices. In this framework in the paper the design of a monopolar dual-band antenna operating in the L1 and L2 GPS bands is presented. The pre-fractal geometry of the antenna has been synthesized by means of a Particle Swarm algorithm for optimizing the values of the electrical parameters within the specifications. In the paper some selected results of numerical simulations are shown and some comparisons between numerical and experimental data are presented. This is the author's version of the final version available at IEEE
On the Effects of Phase Information on the Reconstruction Capabilities of the Iterative Multi-Scaling Strategy
No full textThis paper focuses on the dielectric reconstruction from amplitude-only data by means of the Iterative Multi-Scaling Strategy. Such a methodology is considered to fully exploit the reduced information content achievable from phaseless measurements allowing a satisfactory spatial resolution in the investigation domain. In order to preliminary evaluate the performance of the proposed approach, a representative test case is analyzed and the results are compared with those of the full-data approach
A systematic Approach towards the Solution of the Polysemy Problem in Natural Language Processing
No full textWordNet has been used widely in NLP and semantic applications. Despite the reputation of WordNet, it still suffers from many problems that make it hard to be usable by NLP and semantic applications. The major problem that has been extensively researched last decades is polysemy. Solving the polysemy problem is indispensable because the high polysemous nature of WordNet leads to insufficient quality of NLP and semantic applications results. In this proposal, we describe the polysemy problem, report the state of the art approaches, and introduce a novel approach for solving polysemy
Dalle neuroscienze cognitive alla sociologia
No full textSulla nuova metafisica possiamo ripetere con Pareto che “se oggi, i popoli civili più non credono che il sole, ogni sera, si tuffi nell’oceano, hanno altre credenze che non più di questa si accostano alla realtà. È naturale il desiderio di non appagarsi del come, ma di ricercare anche il perché”. Entro certi limiti, la scienza logico-sperimentale cerca di rispondere. Ma, “poiché di tali limiti sono insofferenti gli uomini (inclusi intellettuali e cosiddetti scienziati), che sprezzando il contingente mirano all’assoluto”, ad essa si aggiungono, “per dare l’ambita risposta, pseudoscienze (o scienze che invadono campi non propri) che interpretano i fatti con il sentimento, con i desideri, con i pregiudizi, con l’opera, spesso inconsapevole, degli interessi, e in tanti altri modi, tutti estranei alla scienza logico-sperimentale”. In tal modo si producono quelle che nel Trattato di sociologia generale si chiamano derivazioni per loro natura variabilissime, variopinte, fugaci, sotto le quali si cela, come per tutti i fatti umani, una parte costante, il residuo. Dunque, alla domanda posta all’inizio del saggio – ove fosse l’azione – essendo l’azione sociologica di fatto l’oggetto centrale delle aspirazioni esplicative e dei risultati prodotti dagli orientamenti di ricerca, in campo neuropsichico e biochimico, presentati – la risposta va da sé. Ma un’azione comunque c’è. Ed è quella stessa dei ricercatori che unitamente agli oggetti indagati abbiamo classificato secondo la teoria dei residui. Gli stessi risultati delle neuroscienze cognitive e della genetica portano di necessità verso la spiegazione sociologica, la sola ultima possibile e credibile nel campo dell’azione umano-sociale. Sono gli stessi risultati delle varie risonanze magnetiche e modelli psico-fisicisti a confermare l’impossibilità della riduzione ai livelli epistemologici inferiori