Automatically evaluating the quality of textual descriptions in cultural heritage records

AbstractMetadata are fundamental for the indexing, browsing and retrieval of cultural heritage resources in repositories, digital libraries and catalogues. In order to be effectively exploited, metadata information has to meet some quality standards, typically defined in the collection usage guidelines. As manually checking the quality of metadata in a repository may not be affordable, especially in large collections, in this paper we specifically address the problem of automatically assessing the quality of metadata, focusing in particular on textual descriptions of cultural heritage items. We describe a novel approach based on machine learning that tackles this problem by framing it as a binary text classification task aimed at evaluating the accuracy of textual descriptions. We report our assessment of different classifiers using a new dataset that we developed, containing more than 100K descriptions. The dataset was extracted from different collections and domains from the Italian digital library "Cultura Italia" and was annotated with accuracy information in terms of compliance with the cataloguing guidelines. The results empirically confirm that our proposed approach can effectively support curators (F1 $$\sim$$ ∼ 0.85) in assessing the quality of the textual descriptions of the records in their collections and provide some insights into how training data, specifically their size and domain, can affect classification performance

Numerical verification of the condenser finite volume model

Numerical modelling of vapour compression systems is very useful for performance optimization through the implementation of suitable model-based control applications; in this context the heat exchangers are the most challenging component to devise, due to phase transition and ensuing discontinuities of the physical properties, and one tool which has proven itself suitable for the task is the finite volume method. A numerical verification of a finite volume model of a brazed plate condenser in counterflow arrangement is carried out, employing a fixed timestep solver; some useful guidelines are suggested to properly choose the solver order, the integration step size and the number of grid elements, balancing the accuracy of the predictions with computational time and model stability and flexibility during the transients, with the ultimate goal to provide a model suited for real-time simulations and control-oriented applications

Effects of pipe angular velocity and oven configuration on tube temperature distribution in the radiative heating of PVC pipes

Abstract Several manufacturing processes in polymer industry aim at obtaining products by deforming preforms or sheets after a heating process. A thorough knowledge of the operating parameters of such heating processes is fundamental to fulfill the often high production requirements with the least energy consumption and to avoid unacceptable defects in the final product. A common example of such an application is the end-forming process of polyvinyl chloride (PVC) tubes, which are enlarged at one end in order to allow pipes connections. The heating phase which comes before the deformation process is usually carried out in ovens equipped with short wave infrared lamps; to ensure uniform heating, pipes rotate with a given angular velocity, which represents a fundamental parameter for the success of the whole manufacturing process. In this work, a transient analysis of the radiative heat exchange between rotating PVC pipes and infrared lamps in an oven for end-forming process has been conducted by means of a finite element model, in order to investigate the influence of cylinder angular velocity on the temperature distribution in the tube. Local view factors have been calculated for different oven configurations and have been expressed as a function of angular velocity, allowing pipe rotation to be simulated as a time-dependent boundary condition, instead of using a moving mesh. Simulations were carried out for different tubes geometries and angular velocities and results were compared with the case of a uniformly irradiated tube in terms of temperature displacement. For a given oven configuration, the results obtained by the numerical model can be used to find a critical angular velocity over which further increase does not lead to appreciable improvements in temperature evenness. The effect of the lamps' relative position was also investigated, showing a significant influence on critical angular velocities obtained. The model realized represents a potential tool to characterize the end-forming process in terms of critical angular velocity, leading to reductions in machine set-up time and product waste due to thermal failure

Welfare institutions, resources, and political learning. Interacting with the State as an Incentive for the Political Participation of Long-Term Unemployed Youth

This paper examines the impact of interactions with welfare institutions on the political partici-pation of long-term unemployed youth in two cities. We assess the role of resource redistribution and of political learning on engagement in protest activities. We use a unique dataset of long-term unemployed youth to predict the probability that long-term unemployed youth participate in protest activities and be-come politically alienated as a result of their interactions with the state. Our study suggests that the impact of staid aid on political participation comes from providing services through the unemployment office and the social aid office rather than from direct payments. However, we do not find strong evidence revealing a process of political learning, as political alienation does not seem to mediate the effect of interactions with the state on protest. The most important finding of our study is that the connection between welfare insti-tutions and political learning is context-dependent. We find a differential effect of interactions with the unemployment office and with the social aid office across cities

Numerical model of an industrial refrigeration system for condensation temperature optimisation

Refrigeration plants in the food industry have a key role, yet are very energy-intensive, which poses a serious problem given the current steep rise of energy prices. In this framework, energy consumption minimisation represents a paramount goal for plant managers, yet most are loathe to test new control strategies in real-life plants, lest normal operation be disrupted and food be spoiled as a consequence. In this view, numerical models able to demonstrate the reduction in energy consumption which can be achieved with suitable conduction strategies, especially in the case when evaporative condensers are employed, appear the ideal tool to provide the manager with an estimation of the potential savings and spur them into adopting such strategies. In this work one such model is developed for the primary loop of the refrigeration plant of a warehouse for food storage located in northern Italy. The choice of the model type is discussed at length, as are modelling issues related to all main components of the loop. The model has been validated with operational data from the real-life plant and employed to determine the optimal condensation pressure corresponding to the minimum total energy consumption according to ambient conditions. The method and model can be applied to other, similar plants in order to minimise their energy consumption

Performance assessment of electro-osmotic flow of rectangular microchannels with smoothed corners

Microchannel heat sinks are a viable alternative to traditional thermal management systems when high fluxes over small surfaces are involved. To avoid high pressure drops especially when liquids are concerned, electro-osmotic flow, a phenomenon which is relevant at the microscales only, can be employed profitably. Joule heating, which occurs every time an electrical current is circulated through a conductor with finite electrical resistance, may hamper the application of electro-osmotic flows significantly; its effects must therefore be investigated, as should the influence of the entry length on the overall transport phenomena which occur in the microchannel, especially so since channels with uniform temperature at the walls tend to be somewhat short, to mitigate heat generation due to Joule heating. In this paper the transport phenomena occurring within a microchannel of rectangular cross-section with uniform wall temperature through which an electro-osmotic flow occurs is studied, while considering the flow fully developed hydrodynamically but thermally developing (Graetz problem). The corners are then smoothed progressively and the effect of this change in the shape of the cross-section over the non-dimensional dissipated power or temperature difference between wall and fluid is investigated using the performance evaluation criteria introduced by Webb. Correlations are suggested for the Poiseuille and Nusselt numbers for all configurations as are criteria to obtain the maximum allowable channel length, i.e. the length of the channel over which the walls start to cool the fluid, owing to Joule heating, in terms of the hydraulic diameter

Automatically evaluating the quality of textual descriptions in cultural heritage records

Metadata are fundamental for the indexing, browsing and retrieval of cultural heritage resources in repositories, digital libraries and catalogues. In order to be effectively exploited, metadata information has to meet some quality standards, typically defined in the collection usage guidelines. As manually checking the quality of metadata in a repository may not be affordable, especially in large collections, in this paper we specifically address the problem of automatically assessing the quality of metadata, focusing in particular on textual descriptions of cultural heritage items. We describe a novel approach based on machine learning that tackles this problem by framing it as a binary text classification task aimed at evaluating the accuracy of textual descriptions. We report our assessment of different classifiers using a new dataset that we developed, containing more than 100K descriptions. The dataset was extracted from different collections and domains from the Italian digital library \u201cCultura Italia\u201d and was annotated with accuracy information in terms of compliance with the cataloguing guidelines. The results empirically confirm that our proposed approach can effectively support curators (F1 3c 0.85) in assessing the quality of the textual descriptions of the records in their collections and provide some insights into how training data, specifically their size and domain, can affect classification performance

Thermal characterization of the end-forming process of PVC pipes: influence of the number of lamps on critical angular velocities

Abstract The end-forming, or belling, of plastic pipes allows them to be joined together to form longer ducts. The first stage of the process entails softening the pipe wall through heating, and defines the properties of the final product. Because of the very low value of thermal conductivity of plastics and to speed heating up, the pipes are placed in ovens whose walls are lined with infra-red short-wave (SW) lamps. The radiation emitted partly penetrates the pipe wall, quickening the process. The heating elements have a straight configuration, and can only be laid axially flush over the oven's wall, the pipes, therefore, must rotate to obtain a circumferentially uniform heating and avoid damage. The threshold speed to avoid scorching while exceeding a desired temperature over the thickness of the pipe wall is defined as "critical angular velocity" and is strictly dependent on pipe geometry and oven characteristics such as the number and layout of lamps. The Authors have already investigated the problem extensively, as is well documented in the literature, yet one aspect still remains to be studied, namely the influence of the number of lamps on the heat flux distribution over the pipe's perimeter and on the critical velocity. In this work, the issue is investigated thoroughly using the same approach previously adopted and recalled in its main aspects in the paper. It is found that even a significant reduction in the number of lamps does not increase threshold velocities to technically unfeasible values. A non-negligible reduction in costs can therefore be achieved without significant impact on the process outcomes

Metrological characterization of a vision-based system for relative pose measurements with fiducial marker mapping for spacecrafts

An improved approach for the measurement of the relative pose between a target and a chaser spacecraft is presented. The selected method is based on a single camera, which can be mounted on the chaser, and a plurality of fiducial markers, which can be mounted on the external surface of the target. The measurement procedure comprises of a closed-form solution of the Perspective from n Points (PnP) problem, a RANdom SAmple Consensus (RANSAC) procedure, a non-linear local optimization and a global Bundle Adjustment refinement of the marker map and relative poses. A metrological characterization of the measurement system is performed using an experimental set-up that can impose rotations combined with a linear translation and can measure them. The rotation and position measurement errors are calculated with reference instrumentations and their uncertainties are evaluated by the Monte Carlo method. The experimental laboratory tests highlight the significant improvements provided by the Bundle Adjustment refinement. Moreover, a set of possible influencing physical parameters are defined and their correlations with the rotation and position errors and uncertainties are analyzed. Using both numerical quantitative correlation coefficients and qualitative graphical representations, the most significant parameters for the final measurement errors and uncertainties are determined. The obtained results give clear indications and advice for the design of future measurement systems and for the selection of the marker positioning on a satellite surface

food production and irrigation and drainage systems development perspective and challenges

A critical problem challenging mankind today is how to manage the intensifying competition for water between expanding urban centres, traditional agricultural activities and in-stream water uses dictated by environmental concerns. In the agricultural sector, the prospects of increasing the gross cultivated area are limited by the dwindling number of economically attractive sites for large-scale irrigation and drainage projects. Therefore the required increase in agricultural production will necessarily rely largely on the affordability to apply new technologies, a more accurate estimation of crop water requirements, and on major improvements in the construction, operation, management and performance of existing irrigation and drainage systems. The failings of present systems and the inability to sustainably exploit surface and groundwater resources can be attributed essentially to poor planning, design, system management and development. This is partly due to the inability of engineers, planners and managers to adequately quantify the effects of irrigation and drainage projects on water resource systems and to use these effects as guidelines for improving technology, design and management [1-4]