1,792 research outputs found

    Human-centric light sensing and estimation from RGBD images: the invisible light switch

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    Lighting design in indoor environments is of primary importance for at least two reasons: 1) people should perceive an adequate light; 2) an effective lighting design means consistent energy saving. We present the Invisible Light Switch (ILS) to address both aspects. ILS dynamically adjusts the room illumination level to save energy while maintaining constant the light level perception of the users. So the energy saving is invisible to them. Our proposed ILS leverages a radiosity model to estimate the light level which is perceived by a person within an indoor environment, taking into account the person position and her/his viewing frustum (head pose). ILS may therefore dim those luminaires, which are not seen by the user, resulting in an effective energy saving, especially in large open offices (where light may otherwise be ON everywhere for a single person). To quantify the system performance, we have collected a new dataset where people wear luxmeter devices while working in office rooms. The luxmeters measure the amount of light (in Lux) reaching the people gaze, which we consider a proxy to their illumination level perception. Our initial results are promising: in a room with 8 LED luminaires, the energy consumption in a day may be reduced from 18585 to 6206 watts with ILS (currently needing 1560 watts for operations). While doing so, the drop in perceived lighting decreases by just 200 lux, a value considered negligible when the original illumination level is above 1200 lux, as is normally the case in offices

    Why are Some Regions More Innovative than Others? The Role of Firm Size Diversity

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    Large labs may spawn spin-outs caused by innovations deemed unrelated to the firm's overall business. Small labs generate demand for specialized services that lower entry costs for others. We develop a theoretical framework to study the interplay of these two localized externalities and their impact on regional innovation. We examine MSA-level patent data during the period 1975-2000 and find that innovation output is higher where large and small labs coexist. The finding is robust to across-region as well as within-region analysis, IV analysis, and the effect is stronger in certain subsamples consistent with our explanation but not the plausible alternatives.

    Designing hybridization: alternative education strategies for fostering innovation in communication design for the territory

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    Within the broad context of design studies, Communication Design for the Territory stands as a hybrid discipline constantly interfacing with other fields of knowledge. It assumes the territorial theme as its specific dimension, aiming to generate communication systems capable of reading the stratifications of places. From an educational perspective, teaching activities are closely linked to research and can take on different levels of complexity: from the various forms of cartographic translation to the design of sophisticated transmedia digital systems. In the wake of COVID-19, this discipline has come to terms with a profoundly changed scenario in terms of limited access to the physical space and the emergence of new technologies for remote access. In this unique context, we propose a pedagogical strategy that focuses on the hybridization of communication artifacts with the aim of fostering design experimentation. As a creative tool, hybridization leads to the design of innovative systems by strategically combining the characteristics of different artifacts to achieve specific communication goals. By experimenting with these creative strategies, students are led to critically reflect on existing communication artifacts’ features and explore original designs that deliberately combine different media, contents, and communication languages in innovative ways. Through hybridization, the methods for territorial knowledge production appear more effective, effectively combining the skills and knowledge embodied in multiple subject areas. The paper presents the experience developed in the teaching laboratories of the DCxT (Communication Design for the Territory) research group of the Design Department of Politecnico di Milano. The teaching experience highlights how hybridization strategies can increase the effectiveness in learning about territorial specificities, in acquiring critical knowledge about communication systems, and in developing innovation strategies that allow to influence the evolution of traditional communication models

    Elastic effects of vacancies in strontium titanate: Short- and long-range strain fields, elastic dipole tensors, and chemical strain

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    We present a study of the local strain effects associated with vacancy defects in strontium titanate and report the first calculations of elastic dipole tensors and chemical strains for point defects in perovskites. The combination of local and long-range results will enable determination of x-ray scattering signatures that can be compared with experiments. We find that the oxygen vacancy possesses a special property -- a highly anisotropic elastic dipole tensor which almost vanishes upon averaging over all possible defect orientations. Moreover, through direct comparison with experimental measurements of chemical strain, we place constraints on the possible defects present in oxygen-poor strontium titanate and introduce a conjecture regarding the nature of the predominant defect in strontium-poor stoichiometries in samples grown via pulsed laser deposition. Finally, during the review process, we learned of recent experimental data, from strontium titanate films deposited via molecular-beam epitaxy, that show good agreement with our calculated value of the chemical strain associated with strontium vacancies.Comment: 14 pages, 11 figures, 4 table

    Carrier mobility and scattering lifetime in electric double-layer gated few-layer graphene

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    We fabricate electric double-layer field-effect transistor (EDL-FET) devices on mechanically exfoliated few-layer graphene. We exploit the large capacitance of a polymeric electrolyte to study the transport properties of three, four and five-layer samples under a large induced surface charge density both above and below the glass transition temperature of the polymer. We find that the carrier mobility shows a strong asymmetry between the hole and electron doping regime. We then employ ab-initio density functional theory (DFT) calculations to determine the average scattering lifetime from the experimental data. We explain its peculiar dependence on the carrier density in terms of the specific properties of the electrolyte we used in our experiments.Comment: 6 pages, 3 figure

    Toward near real-time flood loss estimation: Post-disaster index

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    The increase in the frequency and impact of extreme hydro-meteorological events worldwide highlights the need for more effective financial strategies providing coverage against the economic consequences of such events, particularly in developing countries. Near Real-Time Loss Estimation (NRTLE) models represent a new generation of catastrophe risk models that can serve as a basis for the development of innovative parametric insurance schemes. NRTLE models can help to estimate the impact of an extreme event, in near real time, for instance, through a Post-Disaster Index (PDI), upon which the issued payments depend. This study introduces a new methodology to compute such an index for flood events in the Philippines, which relies on satellite precipitation estimates, exposure information provided by national censuses issued by the Philippine Statistics Authority (PSA), and historic loss data from the EM-DAT International Disaster Loss database. Firstly, the risk model components (hazard, exposure and vulnerability) employed to generate the above index are described. Then, model performance in terms of number of affected residential buildings, estimated by means of the suggested PDI, is analyzed. Finally, an example of parametric insurance coverage based upon the designed PDI is illustrated

    Toward near real-time flood loss estimation: Model structure and event definition

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    Near Real-Time Loss Estimation Models (NRTLEMs) represent effective tools for developing improved parametric insurance products. This type of financial instruments enables rapid payments as they use one or more environmental variables measured immediately after the event and defined as trigger(s), to identify disaster events and predict the consequent impact. This study presents the preliminary development of such a NRTLEM, specific for floods. Given the importance of the event identification within the proposed methodology, different types of triggers are investigated and compared, with special focus on satellite precipitations estimates. NRTLE-based framework for identification of flood events in the Philippines using satellite precipitation estimates is investigated here. The methodology for event identification and the model calibration procedure are discussed. Finally, the model performance is investigated and the optimal configuration of model parameters minimizing basis risk, i.e., the mismatch between insurance claim settlement and the actual losses, is presented for the case-study application

    Satellite precipitation–based extreme event detection for flood index insurance

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    This paper introduces a novel Satellite Precipitation-based Extreme Event Detection (SPEED) model to effectively support parametric or index insurance instruments specifically designed to cover flood risk. Such financial tools are intended to promote fast payouts in the aftermath of a disastrous event. They leverage on measured hazard parameters, gathered immediately after the event and defined as the trigger(s), which are used to identify such hazardous events and estimate their resulting consequences in terms of physical damage and losses. This paper addresses the first step of such a modeling approach, the detection of a flood event, which plays an important role in the overall methodology, determining its performance in terms of false and missed detections. Different types of triggers for identifying flood events, based on satellite precipitation estimates, are investigated, and the overall model performance is assessed for a case-study country (the Philippines). A statistical procedure for selecting the optimal configuration of model parameters is presented. Such an optimal configuration minimizes the so-called basis risk, defined in this study as the mismatch between modeled and actual events. Finally, the accuracy of the proposed approach in terms of event localization is investigated by subdividing the case-study country into three main areas, corresponding to the coarsest administrative levels, and assessing the model's capability to capture events in each considered area. The results from this study confirm that the proposed SPEED model can be effectively used as an input for parametric insurance products, given its ability to identify hazardous events correctly

    Cortisol-induced SRSF3 expression promotes GR splicing, RACK1 expression and breast cancer cells migration

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    Recent data have demonstrated that triple negative breast cancer (TNBC) with high glucocorticoid receptor (GR) expression are associated to therapy resistance and increased mortality. Given that GR alternative splicing generates mainly GRα, responsible of glucocorticoids action, we investigated its role in the regulation of RACK1 (Receptor for Activated C Kinase 1), a scaffolding protein with a GRE (Glucocorticoid Response Element) site on its promoter and involved in breast cancer cells migration and invasion. We provide the first evidence that GRα transcriptionally regulates RACK1 by a mechanism connected to SRSF3 splicing factor, which promotes GRα, essential for RACK1 transcriptional regulation and consequently for cells migration. We also establish that this mechanism can be positively regulated by cortisol. Hence, our data elucidate RACK1 transcriptional regulation and demonstrate that SRSF3 involvement in cells migration implies its role in controlling different pathways thus highlighting that new players have to be considered in GR-positive TNBC
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