1,721,083 research outputs found
Acquisizioni Geomatiche per un sito archeologico lungo la via Francigena: primi risultati
No full text
Il CREAMS : un modello matematico per la stima del deflusso, erosione, trasporto ed inquinamento diffuso derivanti da operazioni agronomiche- Tesi di Dottorato di Ricerca
No full text
Momenti geometrici tridimensionali nel riconoscimento delle forme
No full textSi dimostrano alcuni dei risultati impiegati in un precedente lavoro (D'Urso, 2004) allo scopo di illustrare nei minimi dettagli il procedimento utilizzato per derivare l'espressione dei momenti geometrici di ordine 0 e 1 di poliedri in funzione delle coordinate dei vertici. In particolare, si esplicita l'approccio seguito per pervenire all'espressione dei momenti di ordine 2 riportando altresì, senza dimostrazione per motivi di spazio, la formula relativa ai momenti di ordine 3.We prove some of the results employed in a previous paper (D'Urso, 2004) in order to illustrate in great detail the procedure adopted to derive the expression of the 0th - and 1st-order geometric moments of polyhedra as function of the vertices coordinates. In particular, it is detailed the approach adopted to obtain the expression of the 2nd-order moments by reporting in addition, without proof due to space limitations, the formula pertaining to the 3rd-order moments
The gravity anomaly of a 2D polygonal body having density contrast given by polynomial functions
Full text linkAn analytical solution is presented for the gravity anomaly produced by a 2D body whose geometrical shape is arbitrary and where the density contrast is a polynomial function in both the horizontal and vertical directions. Approximating the real shape of the body by a polygon, the solution is expressed as sum of algebraic quantities that depend only upon the coordinates of the vertices of the polygon and upon the polynomial density function. The solution presented in the paper, which refers to a third-order polynomial function as a maximum, exhibits an intrinsic symmetry that naturally suggests its extension to the case of higher-order polynomials describing the density contrast. Furthermore, the gravity anomaly is evaluated at an arbitrary point that does not necessarily coincide with the origin of the reference frame in which the density function is assigned. Invoking recent results of potential theory, the solution derived in the paper is shown to be singularity-free and numerically robust. The accuracy and effectiveness of the proposed approach is witnessed by the numerical comparisons with examples derived from the existing literature
Sull'applicazione del modello CREAMS ad un'area montana della Basilicata: un esempio di simulazione
No full textVertical stress distribution in isotropic half-space due to surface vertical loadings acting over polygonal domains
Full text linkBy integrating the classical Boussinesq expression we derive analytically the vertical stress distribution induced by pressures distributed with arbitrary laws, up to the third order, over polygonal domains. Thus, one can evaluate in closed form either the vertical stress produced by shell elements, modelling raft foundations by finite elements, acting over a Winkler soil or those induced by a linear pressure distribution simulating axial force and biaxial bending moments over a pad foundation. To this end we include charts and tables, both for rectangular and circular domains, which allow the designer to evaluate the vertical stresses induced by linear load distributions by hand calculations. The effectiveness of the proposed approach is witnessed by the comparison between the analytical results obtained with the proposed formulas and the numerical ones of a FEM discretization of the soil associated with the loading distribution induced by a foundation modeled by plate elements resting on a Winkler soil
Norme tecniche per l'impiego degli apparati digitali di livellazione geometrica
No full textDopo un breve resoconto sullo stato della ricerca scientifica nel campo della moderna livellazione geometrica digitale, viene
illustrata la norma ISO 17123-2. Tale norma, che riguarda sia i livelli
ottico meccanici che gli apparati digitali, viene applicata ad un sistema
di livellazione digitale in commercio. I risultati dei test sono presentati
e discussi, con particolare riferimento ai criteri di valutazione della precisione del livello. Il lavoro si conclude con alcune considerazioni sull’esigenza che venga stabilita una nuova normativa tecnica che integri le
norme ISO e che contempli le modalità di impiego dei moderni apparati digitali per l’esecuzione di livellazioni geometriche.The international standard ISO 17123-2 is illustrated in the paper after a brief review of the state of the art of the scientific research in the field of modern digital levelling. The ISO 17123-2 standard, which concerns both optical -mechanical levels and digital instruments, is applied to a commercial system foe digital levelling. The results of the tests are presented and discussed with particular reference to the criteria for evaluating the precision of the level. The paper ends with some considerations on the necessity that it is established a new technical standard which is integrated into the ISO 17123-2 and encompass the operative techniques for using modern digital instruments for executing geometric levelling
Multi-criteria decision -making methods and their applications for human resources
Full text linkBoth within the formation field and the labor market Multi-Criteria Decision Methods (MCDM) provide a significant support to the management of human resources in which the best choice among several alternatives can be very complex. This contribution addresses fuzzy logic in multi-criteria decision techniques since they have several applications in the management of human resources with the advantage of ruling out mistakes due to the subjectivity of the person in charge of making a choice. Evaluating educational achievements as well as the professional profile of a technician more suitable for a job in a firm, industry or a professional office are valuable examples of fuzzy logic. For all of the previous issues subjectivity is a fundamental aspect so that fuzzy logic, due to the very meaning of the word fuzzy, should be the preferred choice. However, this is not sufficient to justify its use; fuzzy technique has to make the system of evaluation and choice more effective and objective. The methodological structure of the multi-criteria fuzzy criterion is hierarchic and allows one to select the best alternatives in all those cases in which several alternatives are possible; thus, the optimal choice can be achieved by analyzing the different scopes of each criterion and sub-criterion as well as the relevant weights
- …
