688 research outputs found

    Gestione informatizzata dei dati archeologici e dei sistemi GIS. Applicazione al sito di Hierapolis di Frigia

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    The system used for organizing the data from the excavation at Hierapolis, a sample site for this research project, represents an example of the application of the methodology of GIS to a stratigraphically excavated site. The use of this methodology, based on the logical structuring of data in independent layers, makes it possible to reconstruct the micro-dynamics typical of a stratigraphic excavation. Once the archaeological layers are separated, divided and organized according to their geographic position, they are treated as a series of divisible and superimposable layers which can be used in order to create the floor plans of single monuments and, more in general, maps showing the different phases of the city. This type of data management makes it easier to understand the spatial organization and transformation of a city over time

    Solution of the Navier-Stokes equations for a driven cavity

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    The flow field in a lid driven cavity is determined by integration of the incompressible Navier-Stokes equations. The numerical integration is accomplished via an operator splitting method known as the theta-scheme. This splitting separates the problem into the solution of a quasi-stokes problem and a nonlinear convection problem. Some details of solution methods used for the two subproblems and results obtained for the driven cavity are described. The schemes developed for the quasi-Stokes problem are more advanced at this stage than those for the nonlinear problem. However, the approaches used for both parts are outlined. As a model problem, a two dimensional square cavity with sides of unit length and a lid moving with unit velocity from left to right is considered. The Navier-Stokes equations are discretized in space on a uniform staggered or MAC mesh. The time discretization is accomplished via the theta-scheme

    A techno-economic approach for decision-making in metal additive manufacturing: metal extrusion versus single and multiple laser powder bed fusion

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    This work presents a decision-making methodology that allows the merging of quantitative and qualitative decision variables for selecting the optimal metal Additive Manufacturing (AM) technology. The approach is applied on two competing technologies in the field of metal AM industry, i.e., the metal extrusion AM process (metal FFF) and the Laser Powder Bed Fusion process (LPBF) with single and multiple lasers, which represent the benchmark solution currently on the market. A comprehensive techno-economical comparison is presented where the two processes are analysed in terms of process capabilities (quality, easiness of use, setup time, range of possible materials, etc.) and costs, considering two different production scenarios and different parts’ geometries. In the first scenario, the AM system is assumed to be dedicated to one single part production while in this second scenario, the AM system is assumed to be saturated, as devoted to producing a wide mix of part types. For each scenario, two different part types made of 17–4 PH stainless steel are considered as a reference to investigate the effect of shape complexity, part size and production times to select the best technology when metal FFF and LPBF must be considered. The first part type refers to an extrusion die, to represent typical shapes of interest in the tooling industry, while the second part type is an impeller which can be used in many different industrial sectors, ranging from oil and gas to aerospace. In order to include quantitative and qualitative criteria, a decision-making model based on Analytic Hierarchy Process (AHP) is proposed as the enabler tool for decision making. The proposed approach allows to determine the most effective solution depending on the different production configurations and part types and can be used as a guideline and extended to include other technologies in the field of metal AM. On the other side, the critical discussion of the criteria selected, and the results achieved allow to highlight the pros and cons of the competing technologies, thus defining the existing limits to define directions for future research

    Towards a social robot as interface for tourism recommendations

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    The popularity of social robots is steadily increasing, mainly due to the interesting impact they have in several application domains. In this paper, we propose the use of Pepper Robot as an interface of a recommender system for tourism. In particular, we used the robot to interact with the users and to provide them with personalized recommendations about hotels, restaurants, and points of interest in the area. The personalization mechanism encoded in the social robot relies on soft biometrics traits automatically recognized by the robot, as age and gender, user interests and personal facets. All these data are used to feed a neural network that returns as output the most suitable recommendations for the target user. To evaluate the effectiveness of the interaction driven by a social robot, we carried out a user study whose goal was to evaluate: (1) how the robot affects the perceived accuracy of the recommendations; (2) how the user experience and the engagement vary by interacting with a social robot instead of a classic web application. Even if there is a large room for improvement, mainly due to the poor speech recognizer integrated in the Pepper, the results showed that the robot can strongly attract people, thanks to its presence and interaction capabilities. These findings encouraged us in performing a larger field study to test the approach in the wild and to understand whether it can increase the acceptance of recommendations in real environments

    Contrasting Climate Ensembles: A Model-based Visualization Approach for Analyzing Extreme Events

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    AbstractThe use of increasingly sophisticated means to simulate and observe natural phenomena has led to the production of larger and more complex data. As the size and complexity of this data increases, the task of data analysis becomes more challeng- ing. Determining complex relationships among variables requires new algorithm development. Addressing the challenge of handling large data necessitates that algorithm implementations target high performance computing platforms. In this work we present a technique that allows a user to study the interactions among multiple variables in the same spatial extents as the underlying data. The technique is implemented in an existing parallel analysis and visualization framework in order that it be applicable to the largest datasets. The foundation of our approach is to classify data points via inclusion in, or distance to, multivariate representations of relationships among a subset of the variables of a dataset. We abstract the space in which inclusion is calculated and through various space transformations we alleviate the necessity to consider variables’ scales and distributions when making comparisons. We apply this approach to the problem of highlighting variations in climate model ensembles

    Evidence that cells from experimental tumours can activate coagulation factor X.

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    The procoagulant activity of cells from some experimental tumours isolated in culture or in single-cell suspensions from ascitic fluid was investigated. Cells from Lewis lung carcinoma (primary and metastasis), Ehrlich carcinoma ascites and JW sarcoma ascites were able to shorten markedly the recalcification time of normal, Factor VIII- and Factor VII-deficient but not of Factor X-deficient human plasma. The same cells generated thrombin when mixed with a source of prothrombin and Factor X, absorbed bovine serum (as a source of Factor V), phospholipid and calcium chloride. Thrombin formation was not influenced by the presence of Factor VII. Cells from Sarcoma 180 ascites were completely inactive in both test systems. It is concluded that cells from some experimental tumours have the capacity to activate Coagulation Factor X directly. These findings suggest the existence of an alternative "cellular" pathway in the initiation of blood clotting distinct from both the intrinsic and extrinsic mechanisms

    Социально ориентированные программы, KIDS SAVE LIVES (Дети спасают жизни), World Restart a Heart (Перезапусти сердце) и другие кампании для повышения выживаемости при внебольничной остановке сердца

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    Sudden out-of-hospital cardiac arrest (OHCA) is the third leading cause of death in industrialized nations.While educating lay bystanders in CPR is clearly the most important way to increase survival in this third leading cause of death and the community programs are helpful, it is less easy to reach the entire population if programs are not obligatory. Therefore experts see the need for obligatory inclusion of CPR education in schools. And this is exactly our clear expectation to all politicians involved in health care and school politics worldwide. Until this is reality in all countries, we invite everyone to help to convince the responsible politicians and to take part in campaigns like KIDS SAVE LIVES and WRAH.Внезапная внебольничная остановка сердца (ВОС) — третья по частоте причина смерти в развитых странах.Обучение основам СЛР лиц без медицинского образования — наиболее важная стратегия повышения выживаемости при остановке сердца. Программы, включающие такое обучение, весьма эффективны, однако полного охвата населения достичь очень трудно вследствие их необязательного статуса. В связи с этим, по мнению экспертов, СЛР необходимо ввести в школьную программу в качестве обязательного предмета. Именно этого мы ждем от политиков, ответственных за систему здравоохранения и образование, во всех странах. Пока наша цель не достигнута, мы призываем всех помочь нам убедить ответственных лиц и принять участие в таких кампаниях, как KIDS SAVE LIVES и World Restart a Heart

    Fit for the frontline? A focus group exploration of auditory tasks carried out by infantry and combat support personnel

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    In order to preserve their operational effectiveness and ultimately their survival, military personnel must be able to detect important acoustic signals and maintain situational awareness. The possession of sufficient hearing ability to perform job-specific auditory tasks is defined as auditory fitness for duty (AFFD). Pure tone audiometry (PTA) is used to assess AFFD in the UK military; however, it is unclear whether PTA is able to accurately predict performance on job-specific auditory tasks. The aim of the current study was to gather information about auditory tasks carried out by infantry personnel on the frontline and the environment these tasks are performed in. The study consisted of 16 focus group interviews with an average of five participants per group. Eighty British army personnel were recruited from five infantry regiments. The focus group guideline included seven open-ended questions designed to elicit information about the auditory tasks performed on operational duty. Content analysis of the data resulted in two main themes: (1)the auditory tasks personnel are expected to perform and (2) situations where personnel felt their hearing ability was reduced. Auditory tasks were divided into subthemes of sound detection, speech communication and sound localization. Reasons for reduced performance included background noise, hearing protection and attention difficulties. The current study provided an important and novel insight to the complex auditory environment experienced by British infantry personnel and identified 17 auditory tasks carried out by personnel on operational duties. These auditory tasks will be used to inform the development of a functional AFFD test for infantry personnel

    Probing the colloidal gold nanoparticle/aqueous interface with second harmonic generation

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    a b s t r a c t The interface of 16 nm colloidal gold nanoparticles with the aqueous solution in which they are suspended is investigated using second harmonic generation. The population of malachite green freely adsorbing to the gold nanoparticle interface as a function of concentration is obtained. The experimental results are in good agreement with the modified Langmuir model, which includes depletion of the adsorbate bulk concentration. The free energy of adsorption is determined to be À15.4 ± 0.4 kcal/mol with 1.13 ± 0.04 Â 10 3 sites per nanoparticle. These results provide the first direct measurement of the isotherm of molecules adsorbing to colloidal metallic nanoparticles
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