138 research outputs found
NB-IoT via LEO satellites: An efficient resource allocation strategy for uplink data transmission
In this paper, we focus on the use of Low-Eart Orbit (LEO) satellites
providing the Narrowband Internet of Things (NB-IoT) connectivity to the
on-ground user equipment (UEs). Conventional resource allocation algorithms for
the NBIoT systems are particularly designed for terrestrial infrastructures,
where devices are under the coverage of a specific base station and the whole
system varies very slowly in time. The existing methods in the literature
cannot be applied over LEO satellite-based NB-IoT systems for several reasons.
First, with the movement of the LEO satellite, the corresponding channel
parameters for each user will quickly change over time. Delaying the scheduling
of a certain user would result in a resource allocation based on outdated
parameters. Second, the differential Doppler shift, which is a typical
impairment in communications over LEO, directly depends on the relative
distance among users. Scheduling at the same radio frame users that overcome a
certain distance would violate the differential Doppler limit supported by the
NB-IoT standard. Third, the propagation delay over a LEO satellite channel is
around 4-16 times higher compared to a terrestrial system, imposing the need
for message exchange minimization between the users and the base station. In
this work, we propose a novel uplink resource allocation strategy that jointly
incorporates the new design considerations previously mentioned together with
the distinct channel conditions, satellite coverage times and data demands of
various users on Earth. The novel methodology proposed in this paper can act as
a framework for future works in the field.Comment: Tis work has been submitted to the IEEE IoT Journal for possible
publication. Copyright may be transferred without notice, after which this
version may no longer be accessibl
Architectures and Key Technical Challenges for 5G Systems Incorporating Satellites
Satellite Communication systems are a promising solution to extend and
complement terrestrial networks in unserved or under-served areas. This aspect
is reflected by recent commercial and standardisation endeavours. In
particular, 3GPP recently initiated a Study Item for New Radio-based, i.e., 5G,
Non-Terrestrial Networks aimed at deploying satellite systems either as a
stand-alone solution or as an integration to terrestrial networks in mobile
broadband and machine-type communication scenarios. However, typical satellite
channel impairments, as large path losses, delays, and Doppler shifts, pose
severe challenges to the realisation of a satellite-based NR network. In this
paper, based on the architecture options currently being discussed in the
standardisation fora, we discuss and assess the impact of the satellite channel
characteristics on the physical and Medium Access Control layers, both in terms
of transmitted waveforms and procedures for enhanced Mobile BroadBand (eMBB)
and NarrowBand-Internet of Things (NB-IoT) applications. The proposed analysis
shows that the main technical challenges are related to the PHY/MAC procedures,
in particular Random Access (RA), Timing Advance (TA), and Hybrid Automatic
Repeat reQuest (HARQ) and, depending on the considered service and
architecture, different solutions are proposed.Comment: Submitted to Transactions on Vehicular Technologies, April 201
Data circulation in health landscapes
This is the final version. Available from Alma DL Journals via the URL in this record.âŻThe crossing boundaries intends to open a dialogue between Science and Technology Studies, Social studies of Health and the emerging Data Journalism perspective. It explores major issues at stake in contemporary practices of producing and sharing data, with a focus on the COVID-19 pandemic
Occlusione intestinale su briglia in paziente con pregressa diagnosi di sindrome di Ogilv
A case of a 72-year-old man with abdominal pain and ileus is reported. Previous surgery for Ogilvie?s syndrome had been performed.
Despite conservative therapy, the occlusive symptoms worsen. Therefore the patient was submitted to surgery. At laparotomy two abdominal adhesions were found and sectioned.
The differential diagnosis between mechanical ileus and pseudo-obstruction for neuro-mechanics dissociation (Ogilvie?s syndrome) is difficult, particularly in patients with neurodegenerative diseases
Impact of chronic liver disease upon admission on COVID-19 in-hospital mortality: Findings from COVOCA study
Background Italy has been the first Western country to be heavily affected by the spread of SARS-COV-2 infection and among the pioneers of the clinical management of pandemic. To improve the outcome, identification of patients at the highest risk seems mandatory. Objectives Aim of this study is to identify comorbidities and clinical conditions upon admission associated with in-hospital mortality in several COVID Centers in Campania Region (Italy). Methods COVOCA is a multicentre retrospective observational cohort study, which involved 18 COVID Centers throughout Campania Region, Italy. Data were collected from patients who completed their hospitalization between March-June 2020. The endpoint was in-hospital mortality, assessed either from data at discharge or death certificate, whilst all exposure variables were collected at hospital admission. Results Among 618 COVID-19 hospitalized patients included in the study, 143 in-hospital mortality events were recorded, with a cumulative incidence of about 23%. At multivariable logistic analysis, male sex (OR 2.63, 95%CI 1.42â4.90; p = 0.001), Chronic Liver Disease (OR 5.88, 95%CI 2.39â14.46; p<0.001) and malignancies (OR 2.62, 95%CI 1.21â5.68; p = 0.015) disclosed an independent association with a poor prognosis, Glasgow Coma Scale (GCS) and Respiratory Severity Scale allowed to identify at higher mortality risk. Sensitivity analysis further enhanced these findings. Conclusion Mortality of patients hospitalized for COVID-19 appears strongly affected by both clinical conditions on admission and comorbidities. Originally, we observed a very poor outcome in subjects with a chronic liver disease, alongside with an increase of hepatic damage
âA good little tool to get to know yourself a bit betterâ: a qualitative study on usersâ experiences of app-supported menstrual tracking in Europe
Background: Menstrual apps facilitate observation and analysis of menstrual cycles and associated factors through
the collection and interpretation of data entered by users. As a subgroup of health-related apps, menstrual apps
form part of one of the most dynamic and rapidly growing developments in biomedicine and health care.
However, despite their popularity, qualitative research on how people engaging in period-tracking use and
experience these apps remains scarce. Results: An inductive content analysis was performed and eight characteristics of app-supported menstrual
tracking were identified: 1) tracking menstrual cycle dates and regularities, 2) preparing for upcoming periods, 3)
getting to know menstrual cycles and bodies, 4) verifying menstrual experiences and sensations, 5) informing
healthcare professionals, 6) tracking health, 7) contraception and seeking pregnancy, and 8) changes in tracking.
Our study finds that period-tracking via apps has the potential to be an empowering practice as it helps users to be
more aware of their menstrual cycles and health and to gain new knowledge. However, we also show that
menstrual tracking can have negative consequences as it leads to distress in some cases, to privacy issues, and the
work it requires can result in cessation. Finally, we present practical implications for healthcare providers and app
developers.
Conclusions: This qualitative study gives insight into usersâ practices and experiences of app-supported menstrual
tracking. The results provide information for researchers, health care providers and app designers about the
implications of app-supported period-tracking and describe opportunities for patient-doctor interactions as well as
for further development of menstrual apps.This research has received funding from the European Unionâs Horizon 2020
research and innovation program under the Marie SkĆodowska-Curie grant
agreement No 675378
State-of-the-art space mission telecommand receivers
Since their dawning, space communications have been among the strongest driving applications for the development of error correcting codes. Indeed, space-to-Earth telemetry (TM) links have extensively exploited advanced coding schemes, from convolutional codes to Reed-Solomon codes (also in concatenated form) and, more recently, from turbo codes to low-density parity-check (LDPC) codes. The efficiency of these schemes has been extensively proved in several papers and reports. The situation is a bit different for Earth-to-space telecommand (TC) links. Space TCs must reliably convey control information as well as software patches from Earth control centers to scientific payload instruments and engineering equipment onboard (O/B) spacecraft. The success of a mission may be compromised because of an error corrupting a TC message: a detected error causing no execution or, even worse, an undetected error causing a wrong execution. This imposes strict constraints on the maximum acceptable detected and undetected error rates
Heterogeneity of prodromal Parkinson symptoms in siblings of Parkinson disease patients
A prodromal phase of Parkinsonâs disease (PD) may precede motor manifestations by decades. PD patientsâ siblings are at higher risk for PD, but the prevalence and distribution of prodromal symptoms are unknown. The study objectives were (1) to assess motor and non-motor features estimating prodromal PD probability in PD siblings recruited within the European PROPAG-AGEING project; (2) to compare motor and non-motor symptoms to the well-established DeNoPa cohort. 340 PD siblings from three sites (Bologna, Seville, Kassel/Goettingen) underwent clinical and neurological evaluations of PD markers. The German part of the cohort was compared with German de novo PD patients (dnPDs) and healthy controls (CTRs) from DeNoPa. Fifteen (4.4%) siblings presented with subtle signs of motor impairment, with MDS-UPDRS-III scores not clinically different from CTRs. Symptoms of orthostatic hypotension were present in 47 siblings (13.8%), no different to CTRs (p = 0.072). No differences were found for olfaction and overall cognition; German-siblings performed worse than CTRs in visuospatial-executive and language tasks. 3/147 siblings had video-polysomnography-confirmed REM sleep behavior disorder (RBD), none was positive on the RBD Screening Questionnaire. 173/300 siblings had <1% probability of having prodromal PD; 100 between 1 and 10%, 26 siblings between 10 and 80%, one fulfilled the criteria for prodromal PD. According to the current analysis, we cannot confirm the increased risk of PD siblings for prodromal PD. Siblings showed a heterogeneous distribution of prodromal PD markers and probability. Additional parameters, including strong disease markers, should be investigated to verify if these results depend on validity and sensitivity of prodromal PD criteria, or if siblingsâ risk is not elevated
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