85 research outputs found
AI for Zero-Touch Management of Satellite Networks in B5G and 6G Infrastructures
Satellite Communication (SatCom) networks are become more and more integrated with the terrestrial telecommunication infrastructure. In this paper, we shows the current status of the still ongoing European Space Agency (ESA) project”Data-driven Network Controller Orchestration for Real time Network Management-ANChOR”. In particular, we propose a Long Short-Term Memory (LSTM)based methodology to drive the dynamic selection of the optimal satellite gateway station, which will be performed by combining different kinds of information (i.e. traffic profile, network and weather conditions). Some preliminary results on the real world dataset shows the effectiveness of the proposed approach
Atrial functional tricuspid regurgitation: a novel and underappreciated clinical entity
Abstract
Functional or secondary tricuspid regurgitation (FTR) is a progressive disease with a significant negative impact on patient morbidity and mortality. Recently, atrial fibrillation (AF) has been recognized as a cause of FTR (with/without coexisting functional mitral regurgitation) by promoting right atrial (RA) remodeling and secondary tricuspid valve (TV) annulus dilation, even in the absence of right ventricular (RV) dilation or dysfunction. This distinct form of FTR has been called "atriogenic" or "atrial". Recent evidence suggests that the RA is an important player in FTR pathophysiology not only for patients with AF, but also for those in sinus rhythm. Preliminary reports on atrial FTR show that cardioversion with documented maintenance of sinus rhythm promotes TV annulus and RA reverse remodeling and may significantly reduce FTR severity at follow-up. Large-scale studies on the prognostic benefits of rhythm vs rate-control strategy in atrial FTR patients are needed to substantiate specific guidelines indications for this subset of patients
A Quantum Langevin Formulation of Risk-Sensitive Optimal Control
In this paper we formulate a risk-sensitive optimal control problem for
continuously monitored open quantum systems modelled by quantum Langevin
equations. The optimal controller is expressed in terms of a modified
conditional state, which we call a risk-sensitive state, that represents
measurement knowledge tempered by the control purpose. One of the two
components of the optimal controller is dynamic, a filter that computes the
risk-sensitive state.
The second component is an optimal control feedback function that is found by
solving the dynamic programming equation. The optimal controller can be
implemented using classical electronics.
The ideas are illustrated using an example of feedback control of a two-level
atom
Information geometry and local asymptotic normality for multi-parameter estimation of quantum Markov dynamics
This paper deals with the problem of identifying and estimating dynamical
parameters of continuous-time quantum open systems, in the input-output
formalism. First, we characterise the space of identifiable parameters for
ergodic dynamics, assuming full access to the output state for arbitrarily long
times, and show that the equivalence classes of undistinguishable parameters
are orbits of a Lie group acting on the space of dynamical parameters. Second,
we define an information geometric structure on this space, including a
principal bundle given by the action of the group, as well as a compatible
connection, and a Riemannian metric based on the quantum Fisher information of
the output. We compute the metric explicitly in terms of the Markov covariance
of certain "fluctuation operators", and relate it to the horizontal bundle of
the connection. Third, we show that the system-output and reduced output state
satisfy local asymptotic normality, i.e. they can be approximated by a Gaussian
model consisting of coherent states of a multimode continuos variables system
constructed from the Markov covariance "data". We illustrate the result by
working out the details of the information geometry of a physically relevant
two-level system.Comment: 28 pages, 4 figure
Predicting Many Properties of a Quantum System from Very Few Measurements
Predicting the properties of complex, large-scale quantum systems is essential for developing quantum technologies. We present an efficient method for constructing an approximate classical description of a quantum state using very few measurements of the state. This description, called a ‘classical shadow’, can be used to predict many different properties; order log(M) measurements suffice to accurately predict M different functions of the state with high success probability. The number of measurements is independent of the system size and saturates information-theoretic lower bounds. Moreover, target properties to predict can be selected after the measurements are completed. We support our theoretical findings with extensive numerical experiments. We apply classical shadows to predict quantum fidelities, entanglement entropies, two-point correlation functions, expectation values of local observables and the energy variance of many-body local Hamiltonians. The numerical results highlight the advantages of classical shadows relative to previously known methods
Epidemiology of Mycobacterium tuberculosis lineages and strain clustering within urban and peri-urban settings in Ethiopia
Background Previous work has shown differential predominance of certain Mycobacterium tuberculosis (M. tb) lineages and sub-lineages among different human populations in diverse geographic regions of Ethiopia. Nevertheless, how strain diversity is evolving under the ongoing rapid socio-economic and environmental changes is poorly understood. The present study investigated factors associated with M. tb lineage predominance and rate of strain clustering within urban and peri-urban settings in Ethiopia. Methods Pulmonary Tuberculosis (PTB) and Cervical tuberculous lymphadenitis (TBLN) patients who visited selected health facilities were recruited in the years of 2016 and 2017. A total of 258 M. tb isolates identified from 163 sputa and 95 fine-needle aspirates (FNA) were characterized by spoligotyping and compared with international M.tb spoligotyping patterns registered at the SITVIT2 databases. The molecular data were linked with clinical and demographic data of the patients for further statistical analysis. Results From a total of 258 M. tb isolates, 84 distinct spoligotype patterns that included 58 known Shared International Type (SIT) patterns and 26 new or orphan patterns were identified. The majority of strains belonged to two major M. tb lineages, L3 (35.7%) and L4 (61.6%). The observed high percentage of isolates with shared patterns (n = 200/258) suggested a substantial rate of overall clustering (77.5%). After adjusting for the effect of geographical variations, clustering rate was significantly lower among individuals co-infected with HIV and other concomitant chronic disease. Compared to L4, the adjusted odds ratio and 95% confidence interval (AOR; 95% CI) indicated that infections with L3 M. tb strains were more likely to be associated with TBLN [3.47 (1.45, 8.29)] and TB-HIV co-infection [2.84 (1.61, 5.55)]. Conclusion Despite the observed difference in strain diversity and geographical distribution of M. tb lineages, compared to earlier studies in Ethiopia, the overall rate of strain clustering suggests higher transmission and warrant more detailed investigations into the molecular epidemiology of TB and related factors
Permutationally invariant state reconstruction
Feasible tomography schemes for large particle numbers must possess, besides
an appropriate data acquisition protocol, also an efficient way to reconstruct
the density operator from the observed finite data set. Since state
reconstruction typically requires the solution of a non-linear large-scale
optimization problem, this is a major challenge in the design of scalable
tomography schemes. Here we present an efficient state reconstruction scheme
for permutationally invariant quantum state tomography. It works for all common
state-of-the-art reconstruction principles, including, in particular, maximum
likelihood and least squares methods, which are the preferred choices in
today's experiments. This high efficiency is achieved by greatly reducing the
dimensionality of the problem employing a particular representation of
permutationally invariant states known from spin coupling combined with convex
optimization, which has clear advantages regarding speed, control and accuracy
in comparison to commonly employed numerical routines. First prototype
implementations easily allow reconstruction of a state of 20 qubits in a few
minutes on a standard computer.Comment: 25 pages, 4 figues, 2 table
Adaptation and Mal-Adaptation to Ambient Hypoxia; Andean, Ethiopian and Himalayan Patterns
The study of the biology of evolution has been confined to laboratories and model organisms. However, controlled laboratory conditions are unlikely to model variations in environments that influence selection in wild populations. Thus, the study of “fitness” for survival and the genetics that influence this are best carried out in the field and in matching environments
The challenge of unprecedented floods and droughts in risk management
Risk management has reduced vulnerability to floods and droughts globally1,2, yet their impacts are still increasing3. An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data4,5. On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change3
Network analysis of dairy cattle movement and associations with bovine tuberculosis spread and control in emerging dairy belts of Ethiopia
Background: Dairy cattle movement could be a major risk factor for the spread of bovine tuberculosis (BTB) in
emerging dairy belts of Ethiopia. Dairy cattle may be moved between farms over long distances, and hence
understanding the route and frequency of the movements is essential to establish the pattern of spread of BTB
between farms, which could ultimately help to inform policy makers to design cost effective control strategies. The
objective of this study was, therefore, to investigate the network structure of dairy cattle movement and its
influence on the transmission and prevalence of BTB in three emerging areas among the Ethiopian dairy belts,
namely the cities of Hawassa, Gondar and Mekelle.
Methods: A questionnaire survey was conducted in 278 farms to collect data on the pattern of dairy cattle
movement for the last 5 years (September 2013 to August 2018). Visualization of the network structure and analysis
of the relationship between the network patterns and the prevalence of BTB in these regions were made using
social network analysis.
Results: The cattle movement network structure display both scale free and small world properties implying local
clustering with fewer farms being highly connected, at higher risk of infection, with the potential to act as super
spreaders of BTB if infected. Farms having a history of cattle movements onto the herds were more likely to be
affected by BTB (OR: 2.2) compared to farms not having a link history. Euclidean distance between farms and the
batch size of animals moved on were positively correlated with prevalence of BTB. On the other hand, farms having
one or more outgoing cattle showed a decrease on the likelihood of BTB infection (OR = 0.57) compared to farms
which maintained their cattle.
Conclusion: This study showed that the patterns of cattle movement and size of animal moved between farms
contributed to the potential for BTB transmission. The few farms with the bulk of transmission potential could be
efficiently targeted by control measures aimed at reducing the spread of BTB. The network structure described can also
provide the starting point to build and estimate dynamic transmission models for BTB, and other infectious disease
- …