L'iconografia del pellegrinaggio nella scultura Romanica europea e i suoi prototipi neotestamentari

La tesi si propone, dopo un analisi sul significato di pellegrinaggio, le sue differenti modalità e la descrizione delle tre principali mete di pellegrinaggio cristiane,spiegando anche quali fossero le strade che conducevano a queste mete, un'analisi iconografica di alcuni episodi neotestamentari che portarono alla genesi dell'iconografia del pellegrino. Inoltre verrà analizzato l'uso che, di queste iconografie, ne fece la scultura Romanica; per po parlare della funzione che queste iconografie ebbero per i pellegrini

Social Commerce: A Literature Review

The increasing popularity of social networking is providing new opportunities for businesses in electronic commerce. It is evolving in order to adopt Web 2.0 capabilities to support online customer interactions and achieve greater economic value. This trend is referred to as social commerce. This study offers the result of a Systematic Literature Review (SLR) to explain the concept of social commerce. In order to elaborate this article, 64 papers were considered from the main digital libraries that index computer science conferences and journals. Applying a systematic analysis to these papers, it was possible to summarize the existing evidence concerning the social commerce and outline some open challenges

SmartSocialMarket: A Social Commerce Architecture

The evolution of the approach users have with the World Wide Web-particularly towards social media-has led to the need of e-commerce platforms aimed at user interaction. Offering a service focussing only on online shopping is no longer satisfactory. In order to provide a successful user-seller interaction, further Web 2.0 tools need to be offered. This development of electronic shopping-which provides new business opportunities-is called social commerce. This paper aims at describing the SmartSocialMarket architecture, which is based on e-commerce components and, at an upper level, on social components. Social components allow for the provision of tools that can improve the user interaction within the platform, and can also offer new market opportunities to sellers

Bewertung und Minderung des Windrisikos bei Hängebrücken

Within the general framework of risk management, the vulnerability of flexible bridges under wind action is addressed. Particular attention is paid to the risk of aeroelastic instabilities and buffeting oscillations in presence of self-excited phenomena. A computational framework based on semi-empirical cross-sectional models for the wind loading and on the three-dimensional finite-element discretization of the structure is developed. This represents a basic tool for assessing wind risk and it is used to obtain some results in the understanding of bridge behaviour under wind storms and in the comparison of different design solutions. A time-domain model for unsteady wind loading is derived as a development of indicial function load models. Some inaccuracy issues of literature models are solved and the consistency with the quasi-steady limit is ensured. A numerical procedure for identifying the load model coefficients from wind tunnel experimental data in such a way that the reliability of the measured quantities is accounted for is proposed, implemented, and validated. Analyses including structural nonlinearities and damping devices are made possible by the developed time-domain methods. The effects on aeroelastic stability and buffeting response of along-span wind coherence, mean deformations, and load and structural nonlinearities are quantified. Finally, mitigation strategies against aeroelastic instability and excessive buffeting oscillations are discussed. A risk-based comparison of some possible solutions is performed in the special case of a suspension bridge. Crossed hangers, secondary cables with opposed curvature, and tuned mass control devices are considered. The results, rendered in terms of yearly probability of collapse and expected number of days of closure to traffic, easily allow a cost-benefit analysis for deciding among different designs. Interesting results are obtained from the simulation of bridges controlled by tuned mass devices.Im Rahmen des Risikomanagements befasst sich diese Arbeit mit der Vulnerabilität flexibler Brücken unter auftretender Windbelastung. Im Besonderen werden die Risiken der aeroelastischen Instabilitäten und der „Buffeting“-Schwingungen in Gegenwart selbsterregender Phänomene analysiert. Es wird ein Berechnungsansatz entwickelt, der auf halb-empirischen Querschnittsmodellen für die Windlasten und auf einer 3D-FE-Diskretisierung der Struktur basiert. Der Berechnungsansatz bietet ein grundlegendes Werkzeug zur Bewertung der Windgefahr und wird verwendet, um das Verhalten einer Brücke unter starken Windbelastungen besser zu verstehen und um Ausführungslösungen zu vergleichen. Ein Modell für instationäre Windlasten im Zeitbereich wird aus den Grundmodellen der Indizialfunktionen abgeleitet. Einige Ungenauigkeitsprobleme der Literaturmodelle werden gelöst und die Kompatibilität mit dem quasistationären Grenzwert wird sichergestellt. Es wird eine numerische Berechnung zur Bestimmung der Lastmodellkoeffizienten aufgrund experimenteller Windkanaldaten vorgeschlagen, ausgeführt und validiert. Analysen mit strukturellen Nichtlinearitäten und Dämpfungsvorrichtungen werden durch die entwickelte Methode ermöglicht. Die Auswirkungen der Windkohärenz, der Durchschnittsverformungen und der strukturellen Nichtlinearitäten der Belastung und der Struktur auf die aeroelastiche Stabilität und auf die „Buffeting“-Antwort werden quantifiziert. Abschließend werden Vorschläge zur Abminderung des Windrisikos diskutiert. Ein risikobasierter Vergleich möglicher Lösungen, wie gekreuzte Aufhänger, sekundäre Kabel mit gegensätzlicher Krümmung und Schwingungsdämpfer, wird am Beispiel einer Hängebrücke durchgeführt. Die Ergebnisse, in Abhängigkeit der jährlichen Wahrscheinlichkeit eines Einsturzes und der erwarteten Anzahl von Tagen der Verkehrschließung, erlauben, sich fuer ein Design zu entscheiden. Erfolgversprechende Ergebnisse werden bei der Simulation der Brücken mit Schwingungsdämpfern erhalten

Optical and electrical recording of neural activity evoked by graded contrast visual stimulus

BackgroundBrain activity has been investigated by several methods with different principles, notably optical ones. Each method may offer information on distinct physiological or pathological aspects of brain function. The ideal instrument to measure brain activity should include complementary techniques and integrate the resultant information. As a "low cost" approach towards this objective, we combined the well-grounded electroencephalography technique with the newer near infrared spectroscopy methods to investigate human visual function.MethodsThe article describes an embedded instrumentation combining a continuous-wave near-infrared spectroscopy system and an electroencephalography system to simultaneously monitor functional hemodynamics and electrical activity. Near infrared spectroscopy (NIRS) signal depends on the light absorption spectra of haemoglobin and measures the blood volume and blood oxygenation regulation supporting the neural activity. The NIRS and visual evoked potential (VEP) are concurrently acquired during steady state visual stimulation, at 8 Hz, with a b/w "windmill" pattern, in nine human subjects. The pattern contrast is varied (1%, 10%, 100%) according to a stimulation protocol.ResultsIn this study, we present the measuring system; the results consist in concurrent recordings of hemodynamic changes and evoked potential responses emerging from different contrast levels of a patterned stimulus.The concentration of [HbO2] increases and [HHb] decreases after the onset of the stimulus. Their variation shows a clear relationship with the contrast value: large contrast produce huge difference in concentration, while low contrast provokes small concentration difference. This behaviour is similar to the already known relationship between VEP response amplitude and contrast.ConclusionThe simultaneous recording and analysis of NIRS and VEP signals in humans during visual stimulation with a b/w pattern at variable contrast, demonstrates a strong linear correlation between hemodynamic changes and evoked potential amplitude. Furthermore both responses present a logarithmic profile with stimulus contrast

Influenza della velocità di deformazionenel carico di rottura di moschettoni in lega di alluminio e di acciaio

Si analizzano i dati sulla deformabilità, sul lavoro alla rottura e sulla resistenza ottenuti con prove di caduta a velocità di deformazione variabile (Torre CRASC) su moschettoni in lega di alluminio e in acciaio, evidenziando come all’aumentare della velocità di deformazione le caratteristiche di resistenza diminuiscano marcatamente. Queste variazioni vengono messe in relazione ai diversi intervalli dei valori della velocità di deformazione propri della progressione speleologica, torrentistica, alpinistica e ad alte velocità di deformazione (vie ferrate).We analyze data on the deformability, the work on resistance to breakage and obtained evidence of a fall in variable strain rate (Torre CRASC) on snap aluminum alloy and steel, noting that with increasing strain rate characteristics resistance decreases markedly. These changes are made in relation to the different ranges of values of strain rate of its progression caving, canyoning, mountaineering, high strain rate (via ferrata)

Preventive maintenance for heterogeneous industrial vehicles with incomplete usage data

Large fleets of industrial and construction vehicles require periodic maintenance activities. Scheduling these operations is potentially challenging because the optimal timeline depends on the vehicle characteristics and usage. This paper studies a real industrial case study, where a company providing telematics services supports fleet managers in scheduling maintenance operations of about 2000 construction vehicles of various types. The heterogeneity of the fleet and the availability of historical data fosters the use of data-driven solutions based on machine learning techniques. The paper addresses the learning of per-vehicle predictors aimed at forecasting the next-day utilisation level and the remaining time until the next maintenance. We explore the performance of both linear and non-liner models, showing that machine learning models are able to capture the underlying trends describing non-stationary vehicle usage patterns. We also explicitly consider the lack of data for vehicles that have been recently added to the fleet. Results show that the availability of even a limited portion of past utilisation levels enables the identification of vehicles with similar usage trends and the opportunistic reuse of their historical data