267 research outputs found

    Least squares optimization: From theory to practice

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    Nowadays, Nonlinear Least-Squares embodies the foundation of many Robotics and Computer Vision systems. The research community deeply investigated this topic in the last few years, and this resulted in the development of several open-source solvers to approach constantly increasing classes of problems. In this work, we propose a unified methodology to design and develop efficient Least-Squares Optimization algorithms, focusing on the structures and patterns of each specific domain. Furthermore, we present a novel open-source optimization system that addresses problems transparently with a different structure and designed to be easy to extend. The system is written in modern C++ and runs efficiently on embedded systemsWe validated our approach by conducting comparative experiments on several problems using standard datasets. The results show that our system achieves state-of-the-art performances in all tested scenarios

    Reflections on retrofits: Overcoming barriers to energy efficiency among the fuel poor in the United Kingdom

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    To meet targets on fuel poverty, energy efficiency and carbon emissions existing homes need to be more energy efficient. We report the results of a participatory action research project to explore the challenges associated with energy efficiency retrofit programmes and ways to better implement future schemes. Six focus groups were held with 48 participants from a range of energy efficiency roles. Data were analysed thematically using the research question “What are the challenges presented by implementing energy efficiency retrofit programmes”. We identified four themes in the data: Funding mechanisms; Predicting performance; Installation; and People. Challenges include funding mechanisms for retrofit programmes resulting in insufficient time to plan, publicise, implement and evaluate a scheme and insufficient flexibility to specify the most appropriate intervention for individual homes. Site workers sometimes need to adapt retrofit designs because of insufficient detail from the designer and can equate quality of installation with quality of finish. Landlords and occupier behaviour can impact on the programme's success and there is a need for greater information on benefits for landlords and for energy behaviour change interventions run alongside retrofit programmes for occupiers. There is a need for outcome evaluations of retrofit schemes with the results shared with stakeholders

    Guaranteed clustering and biclustering via semidefinite programming

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    Identifying clusters of similar objects in data plays a significant role in a wide range of applications. As a model problem for clustering, we consider the densest k-disjoint-clique problem, whose goal is to identify the collection of k disjoint cliques of a given weighted complete graph maximizing the sum of the densities of the complete subgraphs induced by these cliques. In this paper, we establish conditions ensuring exact recovery of the densest k cliques of a given graph from the optimal solution of a particular semidefinite program. In particular, the semidefinite relaxation is exact for input graphs corresponding to data consisting of k large, distinct clusters and a smaller number of outliers. This approach also yields a semidefinite relaxation for the biclustering problem with similar recovery guarantees. Given a set of objects and a set of features exhibited by these objects, biclustering seeks to simultaneously group the objects and features according to their expression levels. This problem may be posed as partitioning the nodes of a weighted bipartite complete graph such that the sum of the densities of the resulting bipartite complete subgraphs is maximized. As in our analysis of the densest k-disjoint-clique problem, we show that the correct partition of the objects and features can be recovered from the optimal solution of a semidefinite program in the case that the given data consists of several disjoint sets of objects exhibiting similar features. Empirical evidence from numerical experiments supporting these theoretical guarantees is also provided

    The Estimation of Cortical Activity for Brain-Computer Interface: Applications in a Domotic Context

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    In order to analyze whether the use of the cortical activity, estimated from noninvasive EEG recordings, could be useful to detect mental states related to the imagination of limb movements, we estimate cortical activity from high-resolution EEG recordings in a group of healthy subjects by using realistic head models. Such cortical activity was estimated in region of interest associated with the subject's Brodmann areas by using a depth-weighted minimum norm technique. Results showed that the use of the cortical-estimated activity instead of the unprocessed EEG improves the recognition of the mental states associated to the limb movement imagination in the group of normal subjects. The BCI methodology presented here has been used in a group of disabled patients in order to give them a suitable control of several electronic devices disposed in a three-room environment devoted to the neurorehabilitation. Four of six patients were able to control several electronic devices in this domotic context with the BCI system

    Dissecting distinct proteolytic activities of FMDV Lpro implicates cleavage and degradation of RLR signaling proteins, not its deISGylase/DUB activity, in type I interferon suppression

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    Author summary Outbreaks of the picornavirus foot-and-mouth disease virus (FMDV) have significant consequences for animal health and product safety and place a major economic burden on the global livestock industry. Understanding how this notorious animal pathogen suppresses the antiviral type I interferon (IFN-alpha/beta) response may help to develop countermeasures to control FMDV infections. FMDV suppresses the IFN-alpha/beta response through the activity of its Leader protein (L-pro), a protease that can cleave host cell proteins. L(pro)was also shown to have deubiquitinase and deISGylase activity, raising the possibility that L(pro)suppresses IFN-alpha/beta by removing ubiquitin and/or ISG15, two posttranslational modifications that can regulate the activation, interactions and localization of (signaling) proteins. Here, we show that TBK1 and MAVS, two signaling proteins that are important for activation of IFN-alpha/beta gene transcription, are cleaved by L-pro. By generating L(pro)mutants lacking either of these two activities, we demonstrate that L-pro's ability to cleave signaling proteins, but not its deubiquitination/deISGylase activity, correlates with suppression of IFN-beta gene transcription. The type I interferon response is an important innate antiviral pathway. Recognition of viral RNA by RIG-I-like receptors (RLRs) activates a signaling cascade that leads to type I interferon (IFN-alpha/beta) gene transcription. Multiple proteins in this signaling pathway (e.g. RIG-I, MDA5, MAVS, TBK1, IRF3) are regulated by (de)ubiquitination events. Most viruses have evolved mechanisms to counter this antiviral response. The leader protease (L-pro) of foot-and-mouth-disease virus (FMDV) has been recognized to reduce IFN-alpha/beta gene transcription; however, the exact mechanism is unknown. The proteolytic activity of L(pro)is vital for releasing itself from the viral polyprotein and for cleaving and degrading specific host cell proteins, such as eIF4G and NF-kappa B. In addition, L(pro)has been demonstrated to have deubiquitination/deISGylation activity. L-pro's deubiquitination/deISGylation activity and the cleavage/degradation of signaling proteins have both been postulated to be important for reduced IFN-alpha/beta gene transcription. Here, we demonstrate that TBK1, the kinase that phosphorylates and activates the transcription factor IRF3, is cleaved by L(pro)in FMDV-infected cells as well as in cells infected with a recombinant EMCV expressing L-pro.In vitrocleavage experiments revealed that L(pro)cleaves TBK1 at residues 692-694. We also observed cleavage of MAVS in HeLa cells infected with EMCV-L-pro, but only observed decreasing levels of MAVS in FMDV-infected porcine LFPK alpha V beta 6 cells. We set out to dissect L-pro's ability to cleave RLR signaling proteins from its deubiquitination/deISGylation activity, to determine their relative contributions to the reduction of IFN-alpha/beta gene transcription. The introduction of specific mutations, of which several were based on the recently published structure of L(pro)in complex with ISG15, allowed us to identify specific amino acid substitutions that separate the different proteolytic activities of L-pro. Characterization of the effects of these mutations revealed that L-pro's ability to cleave RLR signaling proteins but not its deubiquitination/deISGylation activity correlates with the reduced IFN-beta gene transcription

    Mammals of Italy: An annotated checklist

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    Checklists represent a basic tool for conservation and management of regional faunas. However, our knowledge on species composition in a territory changes over time due to species movements across borders, extinctions, introductions, as well as to new taxonomic evidence. We aimed to provide the most updated data on native and non-native species of mammals occurring, or that used to occur until recently, on the Italian political territory and seas. The checklist only includes species whose taxonomic status was explicitly agreed in the most recent peer-reviewed literature and based on the most updated taxonomic approaches. For each species, we provided the following information: scientific and common name, global and Italian range, relevant information for management and conservation (e.g. whether it is endemic, allochthonous, or listed in international regulations and red list assessments), as well as remarks on taxonomy and distribution. This new check list of Italian mammal fauna includes nine marine and 114 terrestrial species, belonging to seven orders (Erinaceomorpha, Soricomorpha, Chiroptera, Carnivora, Cetartiodactyla, Rodentia, Lagomorpha), and 28 families. Vespertilionidae represents the richest family (n=27 species), followed by Cricetidae (n=12) and Soricidae (n=11). The list includes 15–16 allocthonous species. Considering the relative small size of the country, Italy is confirmed as a hotspot of mammal diversity in Europe, hosting the highest species richness in relation to the total area
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