7,026 research outputs found
Ontology-based explanation of classifiers
The rise of data mining and machine learning use in many applications has brought new challenges related to classification. Here, we deal with the following challenge: how to interpret and understand the reason behind a classifier's prediction. Indeed, understanding the behaviour of a classifier is widely recognized as a very important task for wide and safe adoption of machine learning and data mining technologies, especially in high-risk domains, and in dealing with bias.We present a preliminary work on a proposal of using the Ontology-Based Data Management paradigm for explaining the behavior of a classifier in terms of the concepts and the relations that are meaningful in the domain that is relevant for the classifier
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Rarefied flow between plates of finite length via the coupling approach
This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.The coexistence of rarefied continuum flow regime areas and relatively small elements in which rarefaction effects become important is a typical feature of many complex gas flows micro systems. In rarefied domains, the mean free path of gas molecules is comparable or larger than a characteristic scale of the system. These domains are naturally described by kinetic equation for the velocity distribution function, which involve a considerable effort in terms of CPU time and memory requirements, due to the discretization in both physical and velocity space. The continuum domains are best described by the fluid Navier Stokes (NS) equations in terms of average flow velocity, gas density and temperature. These equations are more efficient, but less accurate in critical rarefied areas. Thus, the development of hybrid solver combining kinetic and continuum models is of great interest especially for applications range from gas flows in micro systems to the aerospace applications, such as high altitude flights. The pressure–driven gas flow of rarified monatomic gas through a two-dimensional short microchannel is considered using hybrid solver. The calculations have been carried out for pressure ratios 0.1, 0.5 and 0.9 and fixed relatively large Knudsen number. The applicability of the solver is discussed via comparison with the kinetic and NS solutions.The European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement ITN GASMEMS no 215504
Numerical Simulation of rivulet build up via lubrication equations
A number of engineering problems involve the evolution of a thin layer of liquid over a non-wettable substrate. For example, CO2 chemical absorption is carried out in packed columns, where ost-combustion CO2 flows up while liquid solvent falls down through a collection of corrugated sheets. Further application include, among others, in-flight icing simulations, moisture ondensation on de-humidifier fins, fogging build up and removal. Here, we present a development of an in-house code numerically solving the 2D lubrication equation for a film flowing down an nclined plate. The disjoining pressure approach is followed, in order to model both the contact line discontinuity and the surface wettability. With respect to the original implementation, the full odeling of capillary pressure terms according to Young- Laplace relation allows to investigate contact angles close to /2. The code is thus validated with literature numerical results, obtained by fully 3D approach (VOF), showing satisfying agreement despite a strong reduction in terms of computational cost. Steady and unsteady wetting dynamics of a developing rivulet are investigated and validated) under different load conditions and for different values of the contact angles
Bifurcation analysis of liquid films over low wettability surfaces
Thin liquid layer evolution over a solid substrate and film instability phenomena are involved in a number of engineering applications: in chemical absorption through structured packing, the corrugated sheets are covered by the liquid solvent, offering an enhanced interface surface between the solvent and the gas solute; in coating process, the liquid pattern influences the resulting coating quality; in condensation over finned dehumidifier, heat transfer performances are influenced by the evolving liquid layer, which may arrange as a droplets population or an ensemble of rivulets. Here, the evolution of a liquid layer flowing down an inclined plate bounded by lateral walls, which is the simplest configuration describing hydrodynamics inside structured packing, is numerically investigated. An in-house code, previously developed and largely validated in case of film instability and rivulet buildup, is used in order to solve governing lubrication equations. The full implementation of capillary pressure allows to simulate contact angles up to 60 . Film break is observed due to instability induced by lateral walls, if the imposed liquid flow rate exceeds a critical value, leading to the formation of a rivulet pattern. Fixing the size of the investigated physical domain, the number of observed rivulets, which strongly influences the resulting wetted area, is traced as a function of the flow characteristics (identified by the Bond number), the substrate wettability and the liquid properties; the corresponding bifurcation diagram is presented
Numerical simulation of shear driven film instability over heterogeneous surfaces via enhanced lubrication theory
The prediction of the transition between continuous film, ensemble of rivulets and moving droplets is crucial in applications such as in-flight icing on airfoil wings or a number of chemical reactors. Here, lubrication theory is used to numerically investigate the stability of a continuous liquid film, driven by shear, over a heterogeneous surface. The disjoining pressure is used to model surface wettability, while the full implementation of the film curvature allows to investigate contact angles up to 60â—¦. Different heterogeneous surface configurations occurring in real problems are investigated. An extended computational campaign records the transition from continuous film to rivulet regime and, if present, the further transition from rivulet to droplets at different flow conditions. A moving grid approach allows for accurate prediction of instability phenomena at low computational cost. The numerical results are successfully validated with experimental evidence in case of critical flow rate leading to a stable dry patch and compared with literature results involving the inherently multiscale in-flight icing phenomenon, providing useful statistical information, required to transfer the present detailed small-scale information into larger scale CFD computational approaches
Eventos: ferramentas estratégicas de comunicação.
A Comunicação Organizacional na Empresa Brasileira de Pesquisa Agropecuária (Embrapa) Ă© definida, em sua polĂtica, como um processo gerencial permanente e sistĂŞmico, que integra as atividades de relacionamento entre organização e pĂşblicos, tendo como objetivo criar e manter os fluxos de informação. Nesse contexto a promoção e realização de eventos Ă© uma das ferramentas de comunicação usadas estrategicamente com o objetivo de criar e reforçar relacionamentos entre empresa e pĂşblicos de interesse, bem como apoiar o processo de transferĂŞncia de tecnologia na Embrapa
MUC1 positive cutaneous metastasis with transepidermal elimination from a breast carcinoma
Breast cancer is the most common cause of cutaneous metastases from internal malignancies. Generally, the neoplastic cells are located in the dermis or hypodermis, while a finding of transepidermal elimination on cutaneous metastases is exceptional. In this report we present a patient with perforating cutaneous metastases from breast cancer with mucin 1 expression. Cutaneous, bone, lung, and hepatic lesions were detected two years after the diagnosis of the primary tumor.Fil: Luna, Amalia. Universidad Nacional de La Plata. Facultad de Ciencias MĂ©dicas. Centro de Investigaciones InmunolĂłgicas Básicas y Aplicadas; ArgentinaFil: Merino, MarĂa Emilia. Universidad Nacional de La Plata. Facultad de Ciencias MĂ©dicas. Centro de Investigaciones InmunolĂłgicas Básicas y Aplicadas; ArgentinaFil: Alberdi, Cecilio G.. Universidad Nacional de La Plata. Facultad de Ciencias MĂ©dicas. Centro de Investigaciones InmunolĂłgicas Básicas y Aplicadas; ArgentinaFil: Abba, MartĂn Carlos. Universidad Nacional de La Plata. Facultad de Ciencias MĂ©dicas. Centro de Investigaciones InmunolĂłgicas Básicas y Aplicadas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Segal Eiras, Amada. Universidad Nacional de La Plata. Facultad de Ciencias MĂ©dicas. Centro de Investigaciones InmunolĂłgicas Básicas y Aplicadas; ArgentinaFil: Croce, MarĂa Virginia. Universidad Nacional de La Plata. Facultad de Ciencias MĂ©dicas. Centro de Investigaciones InmunolĂłgicas Básicas y Aplicadas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
Propagation of semantic information between orthophoto and 3D replica: a H-BIM system for the north transept of Pisa Cathedral
This contribution proposes a methodological approach for the transfer of annotations between orthophotos and 3D digital heritage models, relying on a mesh-based/point-based representation. The workflow leverages on the exploitation of 2D/3D projective relations and on the identification, propagation, modelling and tiling of virtual models of architectural heritage. Referring to the significant case study of Pisa Cathedral, the method is tested to ensure an informative continuum between 2D medias and 3D representations, in terms of morphology, geometry and semantic enrichment. At first, a high resolution ortho-photo is created to support studies related to conservation and restoration, e.g. to highlight degradation patterns and materials as well as to distinguish cracks, frescoed surfaces, decorations. Then, the information is translated from the 2D support to a virtual 3D mockup: this step is essential to ensure a complete understanding of the architectural heritage object, that can thus be studied in its entirety, considering its morphological complexities. The proposed approach provides a more effective system for the transfer and exchange of semantic information from high-resolution orthophotos to semantically rich 3D models, that can be fundamental even in view of the construction of Heritage-Building Information Modeling (H-BIM) environments
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