59,685 research outputs found
Una lettera inedita di Konrad Haebler a Benedetto Croce
No full textIl contributo pubblica e commenta l'unica lettera nota di Konrad Haebler a Benedetto Croce, conservata presso la Fondazione Biblioteca Benedetto Croce di Napoli. Il tema è ovviamente l'ispanistica, cui entrambi hanno dedicato importanti studi: bibliografici l'uno, storico-letterari l'altro
Probabilistic models for vehicle interactions in fatigue assessment of bridges
No full textFatigue assessments of bridges depend on vehicle interactions, occurring when several vehicles travel simultaneously on the bridge or when two individual stress histories, caused by vehicles traveling in different times, generate a more damaging combined stress history. When interactions are significant, stress histories cannot be directly determined using conventional fatigue load models provided in Codes, unless suitable theoretical models for vehicle interactions are available. In the paper, original approaches are proposed to study different aspects of the problem. Concerning interactions due to simultaneity, the novelty is to consider the bridge a service system. Since the process of vehicle arrivals is a Markov process, vehicle interactions can be studied in the framework of the queuing theory. In this way, in the appropriate context, interacting vehicles are equivalent to queued requests (vehicles) in the service system. The method considers two subcases, to be tackled in the given sequence, so that the solution is noticeably simplified. The first subcase refers to vehicles traveling simultaneously in one lane; the second subcase to vehicle and vehicle convoys traveling simultaneously on two or more lanes. In the first subcase the problem is solved considering each lane as a single channel system with a waiting queue, where the number of vehicles in the queue and the waiting time, depending on the number of vehicles in the queue, are limited. A modified vehicle flow on each bridge lane is thus obtained, composed by vehicles and vehicle convoys separately traveling the lane, which is, if relevant, the input for the second subcase. In the second subcase the multilane bridge is modeled as a multichannel system without the waiting queue. When the number of requests exceeds the number of channels, r, the surplus is lost and cannot reenter the system. The results regarding simultaneity are much more relevant than it appears at the first sight: Two relevant examples demonstrated that they can be fruitfully used to implement optimized Monte Carlo algorithms for artificial traffic generation, as well for adaptation of traffic measurements, when flows are modified. Finally, a "non-interacting traffic flow" is obtained, whose elements (vehicle, vehicle convoy, cluster of vehicles) travel individually on the bridge. The global stress history results thus a mere random assembly of the stress histories induced by each element of the non-interacting traffic flow. These stress histories can only combine, as simultaneity interactions are excluded for them. Combination of stress histories is a complex issue, especially when, as in the Eurocodes, fatigue load models are composed by a set of standardized lorries. In fact, questions concerning: Conditions for the combination; stress history which can combine; expected number of occurrences of combined stress histories and of the remaining individual ones; are still open. Really, they can be tackled resorting to sophisticated and time-consuming simulations based on Monte Carlo methods, but elementary solutions have not been proposed so far. The original method proposed here, whose practical application is illustrated referring to an important case study, allows to solve the problem providing simple recursive formulae. Finally, two relevant examples illustrate, with specific reference to the Eurocodes, some important implications of the study
Reaction of mesoionic compounds deriving from cyclic N-acyl-alpha-aminoacids with N-(phenylmethylene)benzenesulfonamide
No full textWe studied the behaviour of bicyclic mesoionic compounds derived from the cyclodehydration of cyclic N-acyl-α-aminoacids 1-4 with N- (phenylmethylene)benzenesulfonamide 5. The reaction affords spirocyclic β- lactams and/or imidazo-condensed products (the 1,3-dipolar cycloaddition adducts) depending on the experimental conditions and on the nature of the substituent R on the mesoionic ring
La chiesa della Croce di Lucca. L’architettura
No full textFounded in the Sixteenth Century by the community of Lucchesi in the Port'Alba area for the cult of SS. Crocifisso venerated in Lucca, the church of Croce di Lucca, together with the adjoining monastery belonging to the Order of Carmelites, was restored in the next Century by the work of Francesco Antonio Picchiatti. During the Eighteenth Century, a new altar designed by Ferdinando Sanfelice was placed in the tribune and sacresty by Giovan Battista Manni was created. After the unification of Italy, with the integration of the Croce di Lucca into the property of the State and the rehousing of the Carmelite nuns elsewhere, an inevitable decadence began. Howewer, yet another thereat loomed on the property that was even greater than the effects of decline and negligence, namely the extension project for the Univesrity of Naples to areas close to the religious complex. After the heavy demolition of the monasteries of the Sapienza and the Croce di Lucca, also the church risked a permanent distruction. A large group of people known as "the friends of the Arts", among whom Benedetto Croce, launched an urgent appeal on the pages of Neapolitan newspapers and managed to save the ancient church of the Croce di Lucca after much controversy, despite a radical cut on the original apsis
Towards Compositional Tree Kernels
No full textDistributional Compositional Semantics (DCS) methods combine lexical vectors according to algebraic operators or functions to model the meaning of complex linguistic phrases. On the other hand, several textual inference tasks rely on supervised kernel-based learning, whereas Tree Kernels (TK) have been shown suitable to the modeling of syntactic and semantic similarity between linguistic instances. While the modeling of DCS for complex phrases is still an open research issue, TKs do not account for compositionality. In this paper, a novel kernel called Compositionally Smoothed Partial Tree Kernel is proposed integrating DCS operators into the TK estimation. Empirical results over Semantic Text Similarity and Question Classification tasks show the contribution of semantic compositions with respect to traditional TKs
Semantic compositionality in tree kernels
No full textKernel-based learning has been largely applied to semantic textual inference tasks. In particular, Tree Kernels (TKs) are crucial in the modeling of syntactic similarity between linguistic instances in Question Answering or Information Extraction tasks. At the same time, lexical semantic information has been studied through the adoption of the so-called Distributional Semantics (DS) paradigm, where lexical vectors are acquired automatically from large corpora. Notice how methods to account for compositional linguistic structures (e.g. grammatically typed bi-grams or complex verb or noun phrases) have been proposed recently by defining algebras on lexical vectors. The result is an extended paradigm called Distributional Compositional Semantics (DCS). Although lexical extensions have been already proposed to generalize TKs towards semantic phenomena (e.g. the predicate argument structures as for role labeling), currently studied TKs do not account for compositionality, in general. In this paper, a novel kernel called Compositionally Smoothed Partial Tree Kernel is proposed to integrate DCS operators into the tree kernel evaluation, by acting both over lexical leaves and non-terminal, i.e. complex compositional, nodes. The empirical results obtained on a Question Classification and Paraphrase Identification tasks show that state-of-the-art performances can be achieved, without resorting to manual feature engineering, thus suggesting that a large set of Web and text mining tasks can be handled successfully by the kernel proposed here
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