1435 research outputs found
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Existence results for strong vector equilibrium problems and their applications
No full textNew existence results for the strong vector equilibrium problem are presented, relying on a well-known separation theorem in infinite dimensional spaces. The main results are applied to strong cone saddle-points and strong vector variational inequalities providing new existence results, and furthermore they allow to recover an earlier result from the literature. <br /
Left invertibility of discrete-time output-quantized systems: the linear case with finite inputs
No full textThis paper studies left invertibility of discrete-time linear output-quantized systems. Quantized outputs are generated according to a given partition of the state-space, while inputs are sequences on a finite alphabet. Left invertibility, i.e. injectivity of I/O map, is reduced to left D-invertibility, under suitable conditions. While left invertibility takes into account membership to sets of a given partition, left D-invertibility considers only membership to a single set, and is much easier to detect. The condition under which left invertibility and left D-invertibility are equivalent is that the elements of the dynamic matrix of the system form an algebraically independent set. Our main result is a method to compute left D-invertibility (so also left invertibility for a full measure matrix set) for all linear systems with no eigenvalue of modulus one. Some examples are presented to show the application of the proposed method
Minimizzazione del makespan mediante un software di scheduling in un Job Shop e in un Flexible Flow Shop
No full textRIASSUNTO: Automazione della pianificazione della produzione tramite un software di scheduling: definizioni e applicazione. A partire da una classificazione dell’architettura delle linee produttive, viene proposto un caso applicativo per mostrare le potenzialità degli algoritmi di simulazione delle sequenze di operazioni su un determinato parco macchine. SUMMARY: Production planning automation by a scheduling software. Overview of the architecture of production lines, case study and potential of simulation algorithms for the sequence of operations on a given set of machines
A Bottom-up Hidden Tree Markov Model
No full textHidden Tree Markov Models describe probability distributions over tree-structured data by defining a top-down generative process from the root to the leaves of the tree. We provide a novel compositional hidden tree Markov model that inverts the generative process, allowing hidden states to better correlate and model the co-occurrence of substructures among the child subtrees of internal nodes. To this end, we introduce a mixed memory approximation that factorizes the joint children-to-parent state transition matrix as a mixture of pairwise transitions. This Technical Report provides and in-depth introduction to the Bottom-Up Hidden Tree Markov Model, including the details of the learning and inference procedures
Untangling the role of eosinophils in trichinellosis: a never-ending story
No full textUntangling the role of eosinophils in trichinellosi
Innovative methods of correlation and orbit determination for space debris
No full textSUMMARY We propose two algorithms to provide a full preliminary orbit of an Earth-orbiting object with a number of observations lower than the classical methods, such as those by Laplace and Gauss. The first one is the Virtual debris algorithm, based upon the admissible region, that is the set of the unknown quantities corresponding to possible orbits for a given observation for objects in Earth orbit (as opposed to both interplanetary orbits and ballistic ones). A similar method has already been successfully used in recent years for the asteroidal case. The second algorithm uses the integrals of the geocentric 2-body motion, which must have the same values at the times of the different observations for a common orbit to exist. We also discuss how to account for the perturbations of the 2-body motion, e.g., the effect
Scheduling: modelli, algoritmi e simulazione
No full textRIASSUNTO A partire da una classificazione dell’architettura delle linee produttive, viene proposto un caso applicativo per mostrare le potenzialità degli algoritmi di simulazione delle sequenze di operazioni su un determinato parco macchine SUMMARY Modeling of the architecture of manufacturing lines, definitions of the scheduling problem and discussion of a case study with different different given machining centers configuration
Valutare gli errori di forma
No full textRIASSUNTO: Ridurre gli scarti dovuti agli errori di forma valutando la minima zona di tolleranza: stato dell’arte e potenzialità degli algoritmi genetici SUMMARY: Minimizing the form error estimation by the minimum zone tolerance method: state of the art and potential of genetic algorithm
3D Printing: La polvere di ottone prende forma
No full textRIASSUNTO: Il presente lavoro si colloca all’interno delle attività di studio del settore della prototipazione rapida (RP) e si prefigge lo scopo di realizzare semplici componenti metallici (in particolare in ottone), con la tecnica del three dimensional printing (3DP). Il lavoro si articola nelle seguenti parti principali: caratterizzazione dei materiali, polvere di ottone e liquido legante realizzazione di una postazione di lavoro e progettazione dell’interfaccia di controllo tuning dei parametri del processo di printing La prima parte ha per oggetto l’analisi della granulometria della polvere di ottone (per la prima volta impiegata in esperienze di 3DP), lo studio della bagnabilità con il liquido legante selezionato (silice colloidale in glicole etilenico) e la valutazione dell’interazione locale polvere-colla con esperienze preliminari alla stampa inkjet. Il secondo punto riguarda l’assemblaggio di una struttura con guide motorizzate per permettere la movimentazione della testina sul piano di lavoro, lo sviluppo di un circuito con microcontrollore per il pilotaggio (con onda quadra) dell’ugello selezionato, e di un programma che coordina gli spostamenti della testina con il controllo dell’accensione dell’ugello in modo da realizzare la geometria di ciascuna sezione del componente 3D. La parte finale coinvolge le numerose esperienze sperimentali sul perfezionamento del sistema e sull’ottimizzazione dei parametri in particolare prima con stampe con inchiostro su carta e metallo per studiare l’influenza del segnale elettrico sulle caratteristiche (forma, dimensioni, velocità) delle goccioline espulse dall’orifizio, successivamente con stampe con liquido legante sul letto di polvere in modo da caratterizzare la linea primitiva, la sezione, il modello 3D. SUMMARY: This work has been carried out within the framework of the rapid prototyping (RP) systems studies and has the aim to build simple metal components (particularly brass) with the technique of the three dimensional printing (3DP). The thesis is divided into the following main parts: characterization of the materials (brass powders and binder) realization of a workbench and developing of a control interface tuning of the printing parameters The first part is related to the particle-size analysis of brass powders (for the fist time employed in 3DP experiences), the study of the wet ability of the selected binder fluid (Colloidal silica in Ethylene glycol) and the evaluation of the interaction grain-binder with preliminary tests before printing with the inkjet-head. The second part regards the assembly of a structure with motorized guides in manner to consent the moving of the head on the workspace, the development of a circuit with microcontroller for the activation (with PWM signal) of the selected nozzle, and of the control program to coordinate the moving of the inkjet-head with the control of the firing of the nozzle in order to realize the desired geometry of each section of the 3D component. The final part deals with the several experimental experiences about the improvement of the system and the optimization of the parameters in particular before with ink printing on paper and metal to study the influence of the PWM signal on the characteristics (size, form, speed) of the droplets produced by the orifice, next with printing with binder on the powderbed in order to characterize the primitive line, the section, the 3D model
Adottare un sistema di visione artificiale
No full textLe potenzialità di applicazione dei sistemi di visione artificiale per nuove applicazioni e gli aspetti da prendere in considerazione per deciderne l’adozione