912 resultados para 280200 Artificial Intelligence and Signal and Image Processing
Resumo:
In recent years, the use of Reverse Engineering systems has got a considerable interest for a wide number of applications. Therefore, many research activities are focused on accuracy and precision of the acquired data and post processing phase improvements. In this context, this PhD Thesis deals with the definition of two novel methods for data post processing and data fusion between physical and geometrical information. In particular a technique has been defined for error definition in 3D points’ coordinates acquired by an optical triangulation laser scanner, with the aim to identify adequate correction arrays to apply under different acquisition parameters and operative conditions. Systematic error in data acquired is thus compensated, in order to increase accuracy value. Moreover, the definition of a 3D thermogram is examined. Object geometrical information and its thermal properties, coming from a thermographic inspection, are combined in order to have a temperature value for each recognizable point. Data acquired by an optical triangulation laser scanner are also used to normalize temperature values and make thermal data independent from thermal-camera point of view.
Resumo:
Massive parallel robots (MPRs) driven by discrete actuators are force regulated robots that undergo continuous motions despite being commanded through a finite number of states only. Designing a real-time control of such systems requires fast and efficient methods for solving their inverse static analysis (ISA), which is a challenging problem and the subject of this thesis. In particular, five Artificial intelligence methods are proposed to investigate the on-line computation and the generalization error of ISA problem of a class of MPRs featuring three-state force actuators and one degree of revolute motion.
Resumo:
Volatile amines are prominent indicators of food freshness, as they are produced during many microbiological food degradation processes. Monitoring and indicating the volatile amine concentration within the food package by intelligent packaging solutions might therefore be a simple yet powerful way to control food safety throughout the distribution chain.rnrnIn this context, this work aims to the formation of colourimetric amine sensing surfaces on different substrates, especially transparent PET packaging foil. The colour change of the deposited layers should ideally be discernible by the human eye to facilitate the determination by the end-user. rnrnDifferent tailored zinc(II) and chromium(III) metalloporphyrins have been used as chromophores for the colourimetric detection of volatile amines. A new concept to increase the porphyrins absorbance change upon exposure to amines is introduced. Moreover, the novel porphyrins’ processability during the deposition process is increased by their enhanced solubility in non-polar solvents.rnrnThe porphyrin chromophores have successfully been incorporated into polysiloxane matrices on different substrates via a dielectric barrier discharge enhanced chemical vapour deposition. This process allows the use of nitrogen as a cheap and abundant plasma gas, produces minor amounts of waste and by-products and can be easily introduced into (existing) roll-to-roll production lines. The formed hybrid sensing layers tightly incorporate the porphyrins and moreover form a porous structure to facilitate the amines diffusion to and interaction with the chromophores.rnrnThe work is completed with the thorough analysis of the porphyrins’ amine sensing performance in solution as well as in the hybrid coatings . To reveal the underlying interaction mechanisms, the experimental results are supported by DFT calculations. The deposited layers could be used for the detection of NEt3 concentrations below 10 ppm in the gas phase. Moreover, the coated foils have been tested in preliminary food storage experiments. rnrnThe mechanistic investigations on the interaction of amines with chromium(III) porphyrins revealed a novel pathway to the formation of chromium(IV) oxido porphyrins. This has been used for electrochemical epoxidation reactions with dioxygen as the formal terminal oxidant.rn
Resumo:
L’obiettivo del progetto è stato quello di realizzare ed analizzare aggregati artificiali creati attraverso geopolimerizzazione e macro-incapsulazione di paraffina in aggregati leggeri espansi, discutendo i loro possibili impieghi nelle pavimentazioni stradali. Dopo un'accurata calibrazione delle miscele geopolimeriche, sono stati realizzati degli aggregati artificiali, in seguito caratterizzati in accordo con la norma UNI EN 10343, con l'intento di sostituire materiali stradali vergini. Contemporaneamente, sono stati prodotti aggregati leggeri impregnati di paraffina (PCM), in grado di cambiare fase una volta raggiunti all'incirca i 3 °C, e successivamente rivestiti da due strati di resina poliestere e polvere di granito, denominati PLA: sfruttandone le proprietà termiche, si è valutato il loro possibile utilizzo come soluzione anti-icing. L’ultima fase della ricerca è stata incentrata nella realizzazione di aggregati geopolimerici espansi e molto porosi che potessero contenere una elevata quantità di PCM, sostituendo l'argilla espansa utilizzata nella produzione degli PLA.
Resumo:
The temporal bone is ideal for low-dose CT because of its intrinsic high contrast. The aim of this study was to retrospectively evaluate image quality and radiation doses of a new low-dose versus a standard high-dose pediatric temporal bone CT protocol and to review dosimetric data from the literature.
Resumo:
The purpose of this experimental study was to investigate the effect of tube tension reduction on image contrast and image quality in pediatric temporal bone computed tomography (CT).
Resumo:
A confocal imaging and image processing scheme is introduced to visualize and evaluate the spatial distribution of spectral information in tissue. The image data are recorded using a confocal laser-scanning microscope equipped with a detection unit that provides high spectral resolution. The processing scheme is based on spectral data, is less error-prone than intensity-based visualization and evaluation methods, and provides quantitative information on the composition of the sample. The method is tested and validated in the context of the development of dermal drug delivery systems, introducing a quantitative uptake indicator to compare the performances of different delivery systems is introduced. A drug penetration study was performed in vitro. The results show that the method is able to detect, visualize and measure spectral information in tissue. In the penetration study, uptake efficiencies of different experiment setups could be discriminated and quantitatively described. The developed uptake indicator is a step towards a quantitative assessment and, in a more general view apart from pharmaceutical research, provides valuable information on tissue composition. It can potentially be used for clinical in vitro and in vivo applications.
Resumo:
Psychogenetic research has emphasised the influence of social factors on a child's intellectual development. In her work, Ms. Dumitrascu examines two such factors; family size and order of birth. However, since these formal parameters tend to be unstable, other more informal factors should be taken into consideration. Of these, perhaps the most interesting is the "style" of parental education, which Ms. Dumitrascu regards as an expression of national traditions at the family level. This educational style is culture dependent. Only a comparative, cross-cultural study can reveal the real mechanism through which educational style influences the development of a child's intellect and personality. Ms. Dumitrascu conducted an experimental cross-cultural study aimed at examining the effects of the family environment on a child's intellectual development. Three distinct populations were involved in her investigation, each having quite a distinct status in their geographical area; Romanians, Romanies (Gypsies) from Romania, and Russians from the Republic of Moldova. She presented her research in the form of a series of articles written in English totalling 85 pages, and also on disc. A significant difference was revealed between the intelligence of a child living in a large family, and that of a child with no brothers or sisters. In the case of Romany children, the gap is remarkably large. Ms. Dumitrascu concludes that the simultaneous action of several negative factors (low socio-economic status, large family size, socio-cultural isolation of a population) may delay child development. Subjected to such a precarious environment, Romany children do not seek self-realisation, but rather struggle to survive the hardship. Most of them remain out of civilisation. Unfortunately, adult Romanies seldom express any concern regarding their children's successful social integration. The school as main socialisation tool has no value for most parents. Ms. Dumitrascu argues the need for a major effort aimed at helping Romany's social integration. She hopes this project will be of some help for psychologists, social workers, teachers, and all those who are interested in the integration into society of minority groups.
Resumo:
Speech melody or prosody subserves linguistic, emotional, and pragmatic functions in speech communication. Prosodic perception is based on the decoding of acoustic cues with a predominant function of frequency-related information perceived as speaker's pitch. Evaluation of prosodic meaning is a cognitive function implemented in cortical and subcortical networks that generate continuously updated affective or linguistic speaker impressions. Various brain-imaging methods allow delineation of neural structures involved in prosody processing. In contrast to functional magnetic resonance imaging techniques, DC (direct current, slow) components of the EEG directly measure cortical activation without temporal delay. Activation patterns obtained with this method are highly task specific and intraindividually reproducible. Studies presented here investigated the topography of prosodic stimulus processing in dependence on acoustic stimulus structure and linguistic or affective task demands, respectively. Data obtained from measuring DC potentials demonstrated that the right hemisphere has a predominant role in processing emotions from the tone of voice, irrespective of emotional valence. However, right hemisphere involvement is modulated by diverse speech and language-related conditions that are associated with a left hemisphere participation in prosody processing. The degree of left hemisphere involvement depends on several factors such as (i) articulatory demands on the perceiver of prosody (possibly, also the poser), (ii) a relative left hemisphere specialization in processing temporal cues mediating prosodic meaning, and (iii) the propensity of prosody to act on the segment level in order to modulate word or sentence meaning. The specific role of top-down effects in terms of either linguistically or affectively oriented attention on lateralization of stimulus processing is not clear and requires further investigations.