106,943 research outputs found
Il rilievo con scanner laser del Tempio "G" di Selinunte. Elaborazione delle scansioni e metodo per l'anastilosi virtuale di una colonna
No full textLa possibilità di misurare in un tempo relativamente ridotto le coordinate tridimensionali di un elevato numero di punti rende i sistemi laser scanner particolarmente idonei al rilievo di frammenti erratici; la disponibilità di dati metrici accurati e puntuali, difficilmente ottenibili con le tecniche tradizionali del rilevamento architettonico, rende possibile condurre processi di discretizzazione e razionalizzazione della morfologia dei singoli frammenti.
In questa sede vengono esposte le fasi di lavoro relative all’orientamento relativo ed assoluto delle scansioni laser del Tempio “G” di Selinunte, ed all’anastilosi virtuale dei rocchi di una colonna del fronte nord del tempio; obiettivo dell’anastilosi è la definizione di un metodo che possa essere utilizzato anche per le altre colonne del tempi
Monitoring gas exchanges in artificial lungs for prolonged circulatory and respiratory support
No full text
PREDICTION OF NUTRITIVE VALUE OF DIETS FOR RABBITS USING AN IN VITRO GAS PRODUCTION TECHNIQUE
No full text[EN] Thirty-one mixed diets for rabbits (DE concentration from 8.44 to 12.29 MJ/kg) were used to predict the digestibility of dry matter (dDM), organic matter (dOM), gross energy (dGE) and digestible energy concentration (DE) from some in vitro gas production parameters, using frozen caecal content from rabbits. Step-wise multiple regression analysis showed that the most significant contribution to the variation expressed by dDM, dOM, dGE and DE arises from crude fibre content (CF). Multiple regression analysis considered more than one independent variable, but it gave only marginally improvements in terms of the accuracy of digestibility prediction. The best equations in terms of R2 and residual standard deviation (RSD) values were: DE (MJ/kg DM) = 0.75 - 0.291 CF - 0.208 ADL + 0.856 GE (R2 = 0.895, RSD 0.279) and dOM (%) = 91.8 - 1.756 CF - 1.283 ADL (R2 = 0.849, RSD 1.655) where CF = crude fibre (%DM), ADL = acid detergent lignin (%DM), GE = gross energy (MJ/kg DM). Dry matter loss (DMl, %) was the in vitro gas production parameter which correlated most closely with dDM, dOM, dGE and DE. The best prediction equations were: DE (MJ/kg DM) = -3.14 + 0.217 DMl + 0.114 B (R2 = 0.734, RSD 0.437) and dOM (%) = - 6.80 + 1.078 DMl + 0.456 B (R2 = 0.691, RSD 2.368), where B is the incubation time (h) at half potential gas. When data of the chemical composition and from fermentation parameters were included concurrently in the model, the most significant contribution to the variation explained of dDM, dOM, dGE and DE still arose from CF. These results suggest that in vitro gas production could be an interesting method of predicting the nutritive value of rabbit diets, but further investigations are required to increase caecal inoculum standardisation and its prediction ability.Stanco, G.; Di Meo, C.; Calabrò, C.; Nizza, A. (2003). PREDICTION OF NUTRITIVE VALUE OF DIETS FOR RABBITS USING AN IN VITRO GAS PRODUCTION TECHNIQUE. World Rabbit Science. 11(4):199-210. https://doi.org/10.4995/wrs.2003.508SWORD19921011
Mining Unclassified Traffic Using Automatic Clustering Techniques
No full textIn this paper we present a fully unsupervised algorithm to identify classes of traffic inside an aggregate. The algorithm leverages on the K-means clustering algorithm, augmented with a mechanism to automatically determine the number of traffic clusters. The signatures used for clustering are statistical representations of the application layer protocols. The proposed technique is extensively tested considering UDP traffic traces collected from operative networks. Performance tests show that it can clusterize the traffic in few tens of pure clusters, achieving an accuracy above 95%. Results are promising and suggest that the proposed approach might effectively be used for automatic traffic monitoring, e.g., to identify the birth of new applications and protocols, or the presence of anomalous or unexpected traffi
On collecting semantics for program analysis
No full textReasoning on a complex system in the abstract interpretation theory starts with a formal description of the system behavior specified by a collecting semantics. We take the common point of view that a collecting semantics is a very precise semantics from which other abstractions may be derived. We elaborate on both the concepts of precision and derivability, and introduce a notion of adequacy which tell us when a collecting semantics is a good choice for a given family of abstractions. We instantiate this approach to the case of first-order functional programs by considering three common collecting semantics and some abstract properties of functions. We study their relative precision and give a constructive characterization of the classes of abstractions which are adequate for the collecting semantics
On the Need for a Common API for Abstract Domains of Object-Oriented Programs
No full textIn the last years almost all families of programming languages, from imperative to functional, logic, object-oriented and machine code, have been subject to static analysis by abstract interpretation. The use of a principled approach to static analysis based on the theory of abstract interpretation provided mathematical tools to reason about program properties and allowed for the rigorous and incremental design of precise and scalable static analyzers, ensuring soundness by construction. The large variety of abstract domains for many different programming languages, the ability to combine and refine them with standard abstract interpretation tools and the availability of mature abstract domain libraries allowed easily porting, reusing and experimenting with techniques born in a specific family to other programming languages and properties. Since the use of abstract interpretation for the analysis of object-oriented languages is less common than in other application fields of static analysis, in order to increase its adoption, we advocate the need to establish a common interface for designing and implementing abstract domains for the static analysis of Java-like programs. This interface should allow developing abstract domains pluggable in a generic abstract interpreter, as it is customary, for example, in abstract interpretation-based static analysis of numerical properties
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