2,813 research outputs found

    Stock market firm-level information and real economic activity

    Get PDF
    We provide evidence that changes in the equity price and volatility of individual firms (measures that approximate the definition of 'granular shock' given in Gabaix, 2010) are key to improve the predictability of aggregate business cycle fluctuations in a number of countries. Specifically, adding the return and the volatility of firm-level equity prices to aggregate financial information leads to a significant improvement in forecasting business cycle developments in four economic areas, at various horizons. Importantly, not only domestic firms but also foreign firms improve business cycle predictability for a given economic area. This is not immediately visible when one takes an unconditional standpoint (i.e. an average across the sample). However, conditioning on the business cycle position of the domestic economy, the relative importance of the two sets of firms - foreign and domestic - exhibits noticeable swings across time. Analogously, the sectoral classification of the firms that in a given month retain the highest predictive power for future IP changes also varies significantly over time as a function of the business cycle position of the domestic economy. Limited to the United States, predictive ability is found to be related to selected balance sheet items, suggesting that structural features differentiate the firms that can anticipate aggregate fluctuations from those that do not help to this aim. Beyond the purely forecasting application, this finding may enhance our understanding of the underlying origins of aggregate fluctuations. We also propose to use the cross sectional stock market information to macro-prudential aims through an economic Value at Risk. JEL Classification: C53, C58, F37, G15Business cycle forecasting, granular shock, international linkages

    Human-Computer Interaction in Intelligent Environments

    Get PDF
    Nowadays, smart devices populate our environments, providing services and being more and more interactive and user-friendly. However, they usually require a centralised unit that processes all the dialogues to produce an answer. On the other hand, ubiquitous and pervasive solutions are a valid alternative, but it is hard to arrange them in a well-organised environment. In this thesis, I question if a ubiquitous infrastructure can be reactive, flexible and scalable without disadvantaging a uniform environment. Reactivity defines rapid interactions; flexibility concerns both network issues and interactions with users, through customised interfaces; scalability, instead, ensures that the adopted model does not have constrained networks' size. This investigation focuses on Human-Computer Interaction studies, because people without a required technological background will be the final users of the system. I propose a novel distributed model where each node is a device that can independently interact with users through natural interfaces; in addition, nodes collaborate with other similar devices to support people. Nodes' intelligence is limited to their own context. In order to improve the collaboration, devices share partial knowledge and have a common strategy to forward requests they are not able to accept. The resulting network is an Intelligent Environment where the intelligence comes from a composition of connected interactive behaviours. I investigated the best approach to navigate requests, proposing a routing algorithm and considering also security and consistency issues. I contextualised this work in both a smart house and a smart museum. With the devised process, I paid specific attention to professionals involved in the design steps. I identified actors with different roles and needs; in order to meet their requirements, I proposed a designing process, with automated solutions that simplify the implementation of the presented model. The system has been tested in simulated scenarios in order to evaluate all the novel parts. Results showed that the designed model is reactive, flexible and scalable. Furthermore, in order to enhance the final outcome, I characterised design patterns to design the network. Future improvements are oriented to the initialisation of the network, that now requires an expert; In addition, a more complex interaction is under investigation to support users in museum visits

    Beacon-Based Service Publishing Framework in Multiservice Wi-Fi Hotspots

    Get PDF
    In an expected future multiaccess and multiservice IEEE 802.11 environment, the problem of providing users with useful service-related information to support a correct rapid network selection is expected to become a very important issue. A feasible short-term 802.11-tailored working solution, compliant with existing equipment, is to publish service information encoded within the SSID information element within beacon frames. This makes it possible for an operator to implement service publishing in 802.11 networks while waiting for a standardized mechanism. Also, this straightforward approach has allowed us to evaluate experimentally the performance of a beacon-based service publishing solution. In fact, the main focus of the paper is indeed to present a quantitative comparison of service discovery times between the legacy scenario, where the user is forced to associate and authenticate with a network point of access to check its service offer, and the enhanced scenario where the set of service-related information is broadcasted within beacons. These discovery times are obtained by processing the results of a measurement campaign performed in a multiaccess/service 802.11 environment. This analysis confirms the effectiveness of the beacon-based approach. We also show that the cost in terms of wireless bandwidth consumption of such solution is low

    Cosmic-ray propagation with DRAGON2: II. Nuclear interactions with the interstellar gas

    Full text link
    Understanding the isotopic composition of cosmic rays (CRs) observed near Earth represents a milestone towards the identification of their origin. Local fluxes contain all the known stable and long-lived isotopes, reflecting the complex history of primaries and secondaries as they traverse the interstellar medium. For that reason, a numerical code which aims at describing the CR transport in the Galaxy must unavoidably rely on accurate modelling of the production of secondary particles. In this work we provide a detailed description of the nuclear cross sections and decay network as implemented in the forthcoming release of the galactic propagation code DRAGON2. We present the secondary production models implemented in the code and we apply the different prescriptions to compute quantities of interest to interpret local CR fluxes (e.g., nuclear fragmentation timescales, secondary and tertiary source terms). In particular, we develop a nuclear secondary production model aimed at accurately computing the light secondary fluxes (namely: Li, Be, B) above 1 GeV/n. This result is achieved by fitting existing empirical or semi-empirical formalisms to a large sample of measurements in the energy range 100 MeV/n to 100 GeV/n and by considering the contribution of the most relevant decaying isotopes up to iron. Concerning secondary antiparticles (positrons and antiprotons), we describe a collection of models taken from the literature, and provide a detailed quantitative comparison.Comment: 22 pages, 12 figure

    Improved multi-user interaction in a smart environment through a preference-based conflict resolution virtual assistant

    Get PDF
    In this work we will examine and develop a system that can assist people in Activities of Daily Life (ADL). This study focuses on resolving conflicts for the requests from different users’ profiles, for instance - elderly, adult and young. The objective of the system is to present a dialogue manager which is able to detect multi-user semantic conflict and to resolve the conflict for improved dialogue informing about its decisions using a system interface Avatar. The system is also able to prioritize requests that occurred among the services of multiple home appliances, as well as to deal with conflicting entities involving a single device. We investigated whether the multi-user context awareness by a Virtual Assistant adds value to the Smart Home concept in recognizing multi-user conflicts dynamically. This work has proposed a preference based method for resolving conflict and evaluated the developed system in a smart home environmen

    Minimum-Fuel Control Strategy for Spacecraft Formation Reconfiguration via Finite-Time Maneuvers

    Get PDF
    This paper addresses the minimum-fuel spacecraft formation reconfiguration maneuver in J2 perturbed near-circular orbits. In this study, only the deputy is assumed to be maneuverable and capable of..

    Combined Point of Care Tools Are Able to Improve Treatment Adherence and Health-Related Quality of Life in Patients with Severe Hemophilia: An Observational Prospective Study

    Get PDF
    Introduction: Ultrasound (US) assessment of joints is an evolving point of care tool for the detection of early joint arthropathy (Napolitano M, Kessler CM. Hemophilia A and B. Consultative Hemostasis and Thrombosis, Kitchens, 4th edition); population pharmacokinetic (pop-PK) studies are adopted as a useful instrument to set the prophylaxis regimen for patients with hemophilia, they may improve adherence (Nagao A.et al. Thromb Res. 2019 Jan; 173:79-84) and reduce the annual bleeding rate (ABR). Adherence to continuous intravenous administrations of factor VIII or Factor IX products is challenging, thus patients may experience breakthrough bleedings while on prophylaxis. Repeated US examinations of joint status have recently been advocated to attempt to remedy sub-optimal medication adherence (Di Minno A et al., Blood Rev. 2019 Jan;33:106-116). Aim of the current prospective analysis was to evaluate the impact of combined US assessment and pop-PK study on adherence to treatment and health related quality of life in patients with severe hemophilia A(HA) and B (HB) under regular prophylaxis. Material and methods: This prospective observational study was performed at a single tertiary center from January 2017 to June 2019. Research was conducted following the Helsinki Declaration. All patients included in the study provided a written informed consent for study participation. Patients with severe HA and HB routinely underwent, as part of regular 12-months follow-up visits, the following: US joints evaluation of elbows, knees and ankles using the HEAD-US protocol, treatment adherence evaluation by VERITAS-Pro questionnaire, health –related quality of life assessment by the standardized EQ-5D,EQ-VAS and pop-PK study (WAPPS-Hemo, McMaster University) as needed (i.e.in case of changes in life style, planned treatment switch); each patient visualised US and his estimated PK profile during medial encounters. Compliance to the prescribed treatment was also determined by analysis of patient diaries with infusion logs. Statistical analysis was performed using the SPSS software version 25.0 (SPSS Chicago, IL). Statistical tests were 2-sided, with a significance threshold of 0.05. Results: Twenty consecutive males with severe haemophilia were included in the current analysis, 13 with severe HA, 2 with HA with previous inhibitors and 5 HB, with a median age of 30 (range 14- 56) years and a median ABR of 5 (range:0-12). Nine patients were under primary prophylaxis, 8 under secondary prophylaxis and 3 under tertiary prophylaxis, they all self-infused at home. Four patients had one target joint and 3 patients had multiple target joints. For each enrolled subject, HEAD-US score, VERITAS-pro, EQ5D and EQ-VAS score were assessed at enrolment (T0) and at 12 (T12) and 24 (T24) months follow-up visits, respectively. Pop-PK was assessed in 11 patients: in 7 (5 HA,2 HB) it was assessed twice, before and after treatment switch to extended half-life (EHL) products, in 4 it was assessed once to modify prophylaxis treatment schedules for a more active life-style (N=2) or weight changes (N=2). Median ABR was 4 at T12 and 3.8 at T24. Reported breakthrough bleeds at T12 were 14, mainly trauma-related (N= 8) or affecting target joints (N=4), they were not reported at T24 in patients with PK-driven modified schedules (N=4) and in 4 patients under EHL treatments. Mean HEAD-US score at T0 resulted 8 (range:0-16), at T24 it was 6 (range:0-16). Mean Veritas-Pro score values were 42.7 at TO, 40.1 at T12 and 38.7 at T24. At T0, EQ-5D mean utility score was 0.82 (range: 0.68-1), at T24, the mean was 0.87 (range:0.72-1). In detail, at 24 months follow-up, there was a statistically significant (p<0.05) improvement in adherence to treatment with particular reference to the dimensions of communication and skipped doses. A tendency toward improved HEAD-US score, higher adherence and better quality of life scores, was observed in particular in patients switched to EHL products at T24, at a mean of 10 months after switching (range: 6-22 months). Conclusion: Several combined measures of haemophilia treatment monitoring, allowing visual assessment of joints status and PK profile estimates by patients have here shown to improve treatment adherence and quality of life in patients with HA and HB, this may be not only related to new available treatments but also to an increased awareness and education of patients

    Mountain glaciers darkening: geochemical characterizazion of cryoconites and their radiative impact on the Vadret da Morteratsch (Swiss Alps)

    Get PDF
    Mountain glaciers represent an important source of fresh water across the globe. It is well known that these reservoirs are seriously threatened by global climate change, and a widespread reduction of glacier extension has been observed in recent years. Surface processes that promote ice melting are driven both by air temperature/precipitation and surface albedo. This latter is mainly influenced by the growth of snow grains and by the impurities content (such as mineral dust, soot, ash etc.). The origin of these light-absorbing impurities can be local or distal, and often, as a consequence of melting processes, they can aggregate on the glacier tongue, forming characteristics cryoconites, that decrease ice albedo and hence promote the melting. In this contribution, we coupled satellite images (EO1 \u2013 Hyperion and Landsat 8 - OLI) and ground hyperspectral data (ASD field spectrometer) for characterizing ice and snow surface reflectance of the Vadret da Morteratsch glacier (Swiss Alps). On the glacier ablation zone, we sampled ice, snow, surface dust and cryoconite material. To evaluate the possible impact of anthropogenic and natural emissions on cryoconites formation, we determined their geochemical composition (through the Neutron Activation Analysis, NAA) and the concentration of Black Carbon (BC), Organic Carbon (OC), Elemental Carbon (EC) and Levoglucosan. From satellite data, we computed the Snow Darkening Index (SDI), which is non-linearly correlated with dust content in snow. Results showed that, during 2015 summer season, ice albedo in the ablation zone reached very low values of about 0.1-0.2. The darkening of the glacier can be attributed to the impact of surface dust (from lateral moraine and Saharan desert) and cryoconites, coupled with grain growth driven by the extremely warm 2015 summer. The geochemical characterization of non-ice material contained in the cryoconites can provide important information regarding their source and the possible impact of anthropogenic emissions on cryoconites formation and evolution

    DRAGON2: new features on energy losses treatment

    Get PDF
    In recent years we witnessed several experiments measuring a large set of observables related to Cosmic-ray physics with an unprecedented level of precision. In order to be able to fully exploit this great amount of new data we must act to refine our theoretical predictions. This can be achieved by building more realistic models of Cosmic-ray Galactic transport. The DRAGON project has been pursued in order to model Cosmic-rays propagation under realistic conditions and to allow a comparison with a wide set of experimental data. Studies brought forth with DRAGON showed how a treatment of Cosmic rays energy losses as realistic as possible is pivotal. In DRAGON2, the new version of the code, a more accurate, second order scheme for Cosmic Rays energy losses is implemented. In addition, the new version of the code allows us to investigate the impact of different models for Interstellar Radiation Field or galactic magnetic field. We present comparison between the previous energy losses approach and the new one, as well as validation test by comparing our numerical results with a set of analytical solutions. We study in particular the interplay of diffusion, reacceleration, and energy losses in a realistic case, and their impact on leptonic spectrum
    corecore