Using gravity models for the evaluation of new university site locations: a case study

A fundamental aspect of competitive spatial models is the choice behaviour of potential customers to patronize a facility. Most of the models used to describe this phenomenon are essentially based on the adaptation of Newton’s law of gravitation to the economic case (gravity model). This paper shows an application of this model to describe the behaviour of potential students in the choice of a university site. The results provided by the model have been compared with the actual data and show that the gravity model can describe the behaviour of potential students with good approximation

Using Apache Lucene to Search Vector of Locally Aggregated Descriptors

Surrogate Text Representation (STR) is a profitable solution to efficient similarity search on metric space using conventional text search engines, such as Apache Lucene. This technique is based on comparing the permutations of some reference objects in place of the original metric distance. However, the Achilles heel of STR approach is the need to reorder the result set of the search according to the metric distance. This forces to use a support database to store the original objects, which requires efficient random I/O on a fast secondary memory (such as flash-based storages). In this paper, we propose to extend the Surrogate Text Representation to specifically address a class of visual metric objects known as Vector of Locally Aggregated Descriptors (VLAD). This approach is based on representing the individual sub-vectors forming the VLAD vector with the STR, providing a finer representation of the vector and enabling us to get rid of the reordering phase. The experiments on a publicly available dataset show that the extended STR outperforms the baseline STR achieving satisfactory performance near to the one obtained with the original VLAD vectors.Comment: In Proceedings of the 11th Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISIGRAPP 2016) - Volume 4: VISAPP, p. 383-39

Paired cut-wire arrays for enhanced transmission of transverse-electric fields through sub-wavelength slits in a thin metallic screen

It has recently been shown that the transmission of electromagnetic fields through sub-wavelength slits (parallel to the electric field direction) in a thin metallic screen can be greatly enhanced by covering one side of the screen with a metallic cut-wire array laid on a dielectric layer. In this Letter, we show that a richer phenomenology (which involves both electric- and magnetic-type resonances) can be attained by pairing a second cut-wire array at the other side of the screen. Via a full-wave comprehensive parametric study, we illustrate the underlying mechanisms and explore the additional degrees of freedom endowed, as well as their possible implications in the engineering of enhanced transmission phenomena.Comment: 4 pages, 8 figures; slight corrections in Figs. 1, 2, and

Radio emission from dark matter annihilation in the Large Magellanic Cloud

The Large Magellanic Cloud, at only 50 kpc away from us and known to be dark matter dominated, is clearly an interesting place where to search for dark matter annihilation signals. In this paper, we estimate the synchrotron emission due to WIMP annihilation in the halo of the LMC at two radio frequencies, 1.4 and 4.8 GHz, and compare it to the observed emission, in order to impose constraints in the WIMP mass vs. annihilation cross section plane. We use available Faraday rotation data from background sources to estimate the magnitude of the magnetic field in different regions of the LMC's disc, where we calculate the radio signal due to dark matter annihilation. We account for the e+ e- energy losses due to synchrotron, Inverse Compton Scattering and bremsstrahlung, using the observed hydrogen and dust temperature distribution on the LMC to estimate their efficiency. The extensive use of observations, allied with conservative choices adopted in all the steps of the calculation, allow us to obtain very realistic constraints.Comment: 9 pages, 7 figure

Epidermal inclusion cyst of the breast . A literature review

An epidermal inclusion cyst (EIC) of the breast is a rare, benign condition that may potentially be malignant. The present study conducted a systematic review of the literature in order to identify pathological hypotheses, clinical characteristics, and diagnostic and treatment options. A search for relevant studies was conducted through the Scopus, Embase and Medline databases during September 2014. The search term employed was ῾epidermal inclusion cyst breast᾽. Studies were selected if they contained adequate information regarding symptoms at presentation, diagnostic tools, pathology, characteristics, type of procedure performed and follow-up routines. A total of 35 papers describing 91 patients affected by EIC of the breast were identified. Following this, a total of 82 patients, including an additional case supplied from the present study, were selected for further analysis. EIC of the breast typically occurs during the fifth decade of life. A palpable mass of the breast was present in 65 (79%) patients. Ultrasonographic imaging was consistently utilized as a diagnostic tool in all the cases analyzed, whereas fine-needle aspiration cytology was used in 70% of the cases and mammography in 65%. No tumor recurrence was reported at a mean follow-up time of 53 months. The present study demonstrated that elliptical excision is the preferred treatment for EIC of the breast, with pathological analysis required to exclude malignancy

Models for the schedule optimization problem at a public transit terminal

This work deals with the proposal of some models for the schedule optimization problem for public transit networks. In particular, we consider the case of a transit terminal where passengers are supposed to split among different lines of a service, or even change mode of transportation in case of intermodal systems. Starting from a given schedule for the transit lines arriving at the terminal, the aim is to decide the optimal schedule for the output lines, in such a way to balance the operative costs of the service and the passenger waiting time at the transit terminal. We propose two different models for this problem, which present strong similarities with some well known combinatorial optimization models. Computational results are also presented, showing the suitability of the models to solve real case studies

Aero-Thermo-Dynamic Analysis of a Low Ballistic Coefficient Deployable Capsule in Earth Re-Entry

The paper deals with a microsatellite and the related deployable recovery capsule. The aero-brake is folded at launch and deployed in space and is able to perform a de-orbiting controlled re-entry. This kind of capsule, with a flexible, high temperature resistant fabric, thanks to its lightness and modulating capability, can be an alternative to the current “conventional” recovery capsules. The present authors already analyzed the trajectory and the aerodynamic behavior of low ballistic coefficient capsules during Earth re-entry and Mars entry. In previous studies, aerodynamic longitudinal stability analysis and evaluation of thermal and aerodynamic loads for a possible suborbital re-entry demonstrator were carried out in both continuum and rarefied regimes. The present study is aimed at providing preliminary information about thermal and aerodynamic loads and longitudinal stability for a similar deployable capsule, as well as information about the electronic composition of the plasma sheet and its possible influence on radio communications at the altitudes where GPS black-out could occur. Since the computer tests were carried out at high altitudes, therefore in rarefied flow fields, use of Direct Simulation Monte Carlo codes was mandatory. The computations involved both global aerodynamic quantities (drag and longitudinal moment coefficients) and local aerodynamic quantities (heat flux and pressure distributions along the capsule surface). The results verified that the capsule at high altitude (150 km) is self-stabilizing; it is stable around the nominal attitude or at zero angle of attack and unstable around the reverse attitude or at 180 deg angle of attack. The analysis also pointed out the presence of extra statically stable equilibrium trim points

Relaxation due to random collisions with a many-qudit environment

We analyze the dynamics of a system qudit of dimension mu sequentially interacting with the nu-dimensional qudits of a chain playing the ore of an environment. Each pairwise collision has been modeled as a random unitary transformation. The relaxation to equilibrium of the purity of the system qudit, averaged over random collisions, is analytically computed by means of a Markov chain approach. In particular, we show that the steady state is the one corresponding to the steady state for random collisions with a single environment qudit of effective dimension nu_e=nu*mu. Finally, we numerically investigate aspects of the entanglement dynamics for qubits (mu=nu=2) and show that random unitary collisions can create multipartite entanglement between the system qudit and the qudits of the chain.Comment: 7 pages, 6 figure

Towards Syntax-Aware Editors for Visual Languages

AbstractEditors for visual languages should provide a user-friendly environment supporting end users in the composition of visual sentences in an effective way. Syntax-aware editors are a class of editors that prompt users into writing syntactically correct programs by exploiting information on the visual language syntax. In particular, they do not constrain users to enter only correct syntactic states in a visual sentence. They merely inform the user when visual objects are syntactically correct. This means detecting both syntax and potential semantic errors as early as possible and providing feedback on such errors in a non-intrusive way during editing. As a consequence, error handling strategies are an essential part of such editing style of visual sentences.In this work, we develop a strategy for the construction of syntax-aware visual language editors by integrating incremental subsentence parsers into free-hand editors. The parser combines the LR-based techniques for parsing visual languages with the more general incremental Generalized LR parsing techniques developed for string languages. Such approach has been profitably exploited for introducing a noncorrecting error recovery strategy, and for prompting during the editing the continuation of what the user is drawing