Automatic Scheduling for a Ground Segment as a Service Platform Dedicated to Small Satellites

Together with the development of nano, micro, and small satellite missions and constellations, the necessity for efficient and tailored ground segments is raising. The peculiarities of the market together with the technological developments of the recent years have led to the idea of ground segment as a service. To meet these needs Leaf Space introduced Leaf Line. An essential part of such service consists of scheduling contact windows over the worldwide-deployed network of ground stations. This is an NP-hard problem, which is often solved with methods belonging to the class of operational research. Generally, the orbits of small satellites are very low, characterized by short-timed contact windows. This condition leads to needs way different from those associated to long-lived high-orbit satellites, which most of the literature on scheduling algorithms for telecommunication systems is focused on. Furthermore, a service dedicated to SMEs and NewSpace startups brings additional challenges linked to customer needs. These peculiarities require the development of new, tailored, scheduling algorithms. In the proposed strategy it is assumed to have no information about the state of the satellite (stored data and available energy), and that start and end of contact windows are fixed. In this work, the scheduling is treated as a highly constrained combinatorial optimization problem; various approaches are described and then compared. Such algorithms are iterative, and they all leverage the structure of the problem; specifically, many efforts are made to appropriately reduce the search space. Although optimality cannot be guaranteed, good solutions that are reasonably close to optimal can be obtained. It is found that depending on the problem settings, different algorithms can stand out as the best ones. This paper presents the work done on the scheduling library that is currently powering the Leaf Line network: this platform is offering an easy-to-use, cloud-based and high-availability ground segment service for small satellites operators

Maximize Contact Availability of SmallSat Clusters through MSPA Technique on GSaaS

The Mission Launch date: 07 November 2021 Mission name: KSM1 (Kleos Scouting Mission) Satellites names: KSM1-A, KSM1-B, KSM1-C, KSM1-D NORAD-ID: 46912, 46914, 46906, 46907 Application: RF Reconnaissance and Geospatial Intelligence Mission characteristics: Kleos Space SA (KSS) Scouting Mission (KSM) first cluster of spacecraft, was launched on the 7th of November 2021, comprising four 6U cubesat flying in a close formation. The formation maintains the along and across track distance between the four spacecraft, enabling KSS proprietary algorithms to geolocate Radio Frequency transmitters. GSaaS: Leaf Space provides communication through their Leaf Line GSaaS (Ground Segment as-a-Service) with stations in Italy and Spain supporting the mission with UH

Pro-Environmental Behaviors: Determinants and Obstacles among Italian University Students

The awareness of citizens concerning the health risks caused by environmental pollution is growing, but studies on determinants of pro-environmental behaviors have rarely examined health-related aspects. In this study, we investigated these determinants using data from a large survey among Italian university students (15 Universities: 4778 filled questionnaires). Besides the health-related aspects, represented by environmental health risk perception and functional health literacy, we considered social and demographic characteristics (gender, area of residence, sources of information, trust in institutional and non-institutional subjects, and students' capacity of positive actions, indicated as internal locus of control). The attitudes towards pro-environmental behaviors were positive for more than 70% of students and positively related with health risk perception, internal locus of control, and health literacy. The correspondence between the positive attitudes towards pro-environmental behaviors and the real adoption of such behaviors was approximately 20% for most behaviors, except for the separate collection of waste (60%). Such a discrepancy can be attributable to external obstacles (i.e., lack of time, costs, lack of support). The health-related aspects were linked to the pro-environmental attitudes, but to a lesser extent to pro-environmental behaviors, owing to the complexity of their determinants. However, they should be taken in account in planning education interventions

Pro-environmental behaviors: Determinants and obstacles among italian university students

none31The awareness of citizens concerning the health risks caused by environmental pollution is growing, but studies on determinants of pro-environmental behaviors have rarely examined health-related aspects. In this study, we investigated these determinants using data from a large survey among Italian university students (15 Universities: 4778 filled questionnaires). Besides the health-related aspects, represented by environmental health risk perception and functional health literacy, we considered social and demographic characteristics (gender, area of residence, sources of information, trust in institutional and non-institutional subjects, and students’ capacity of positive actions, indicated as internal locus of control). The attitudes towards pro-environmental behaviors were positive for more than 70% of students and positively related with health risk perception, internal locus of control, and health literacy. The correspondence between the positive attitudes towards pro-environmental behaviors and the real adoption of such behaviors was approximately 20% for most behaviors, except for the separate collection of waste (60%). Such a discrepancy can be attributable to external obstacles (i.e., lack of time, costs, lack of support). The health-related aspects were linked to the pro-environmental attitudes, but to a lesser extent to pro-environmental behaviors, owing to the complexity of their determinants. However, they should be taken in account in planning education interventions.openCarducci A.; Fiore M.; Azara A.; Bonaccorsi G.; Bortoletto M.; Caggiano G.; Calamusa A.; De Donno A.; De Giglio O.; Dettori M.; Di Giovanni P.; Di Pietro A.; Facciola A.; Federigi I.; Grappasonni I.; Izzotti A.; Libralato G.; Lorini C.; Montagna M.T.; Nicolosi L.K.; Paladino G.; Palomba G.; Petrelli F.; Schiliro T.; Scuri S.; Serio F.; Tesauro M.; Verani M.; Vinceti M.; Violi F.; Ferrante M.Carducci, A.; Fiore, M.; Azara, A.; Bonaccorsi, G.; Bortoletto, M.; Caggiano, G.; Calamusa, A.; De Donno, A.; De Giglio, O.; Dettori, M.; Di Giovanni, P.; Di Pietro, A.; Facciola, A.; Federigi, I.; Grappasonni, I.; Izzotti, A.; Libralato, G.; Lorini, C.; Montagna, M. T.; Nicolosi, L. K.; Paladino, G.; Palomba, G.; Petrelli, F.; Schiliro, T.; Scuri, S.; Serio, F.; Tesauro, M.; Verani, M.; Vinceti, M.; Violi, F.; Ferrante, M

Observation of Hadronic W Decays in t-tbar Events with the Collider Detector at Fermilab

We observe hadronic W decays in t-tbar -> W (-> l nu) + >= 4 jet events using a 109 pb-1 data sample of p-pbar collisions at sqrt{s} = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). A peak in the dijet invariant mass distribution is obtained that is consistent with W decay and inconsistent with the background prediction by 3.3 standard deviations. From this peak we measure the W mass to be 77.2 +- 4.6 (stat+syst) GeV/c^2. This result demonstrates the presence of two W bosons in t-tbar candidates in the W (-> l nu) + >= 4 jet channel.Comment: 20 pages, 4 figures, submitted to PR

Search for charged Higgs decays of the top quark using hadronic tau decays

We present the result of a search for charged Higgs decays of the top quark, produced in $p\bar{p}$ collisions at $\surd s =$ 1.8 TeV. When the charged Higgs is heavy and decays to a tau lepton, which subsequently decays hadronically, the resulting events have a unique signature: large missing transverse energy and the low-charged-multiplicity tau. Data collected in the period 1992-1993 at the Collider Detector at Fermilab, corresponding to 18.7$\pm$0.7~pb$^{-1}$, exclude new regions of combined top quark and charged Higgs mass, in extensions to the standard model with two Higgs doublets.Comment: uuencoded, gzipped tar file of LaTeX and 6 Postscript figures; 11 pp; submitted to Phys. Rev.

Inclusive jet cross section in pˉp{\bar p p} collisions at s=1.8\sqrt{s}=1.8 TeV

The inclusive jet differential cross section has been measured for jet transverse energies, $E_T$, from 15 to 440 GeV, in the pseudorapidity region 0.1$\leq | \eta| \leq$0.7. The results are based on 19.5 pb$^{-1}$ of data collected by the CDF collaboration at the Fermilab Tevatron collider. The data are compared with QCD predictions for various sets of parton distribution functions. The cross section for jets with $E_T>200$ GeV is significantly higher than current predictions based on O($\alpha_s^3$) perturbative QCD calculations. Various possible explanations for the high-$E_T$ excess are discussed.Comment: 8 pages with 2 eps uu-encoded figures Submitted to Physical Review Letter

Measurement of the Associated γ+μ±\gamma + \mu^\pm Production Cross Section in ppˉp \bar p Collisions at s=1.8\sqrt{s} = 1.8 TeV

We present the first measurement of associated direct photon + muon production in hadronic collisions, from a sample of 1.8 TeV $p \bar p$ collisions recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily from the Compton scattering process $cg \to c\gamma$, with the final state charm quark producing a muon. Hence this measurement is sensitive to the charm quark content of the proton. The measured cross section of $29\pm 9 pb^{-1}$ is compared to a leading-order QCD parton shower model as well as a next-to-leading-order QCD calculation.Comment: 12 pages, 4 figures Added more detailed description of muon background estimat

Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron

We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles (transverse momentum pT > 0.5 GeV/c, pseudorapidity |\eta| < 1) produced in association with large transverse momentum jets (~2.2 fb-1) or with Drell-Yan lepton-pairs (~2.7 fb-1) in the Z-boson mass region (70 < M(pair) < 110 GeV/c2) as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan production) or the leading jet (in high-pT jet production) in each event to define three regions of \eta-\phi space; toward, away, and transverse, where \phi is the azimuthal scattering angle. For Drell-Yan production (excluding the leptons) both the toward and transverse regions are very sensitive to the underlying event. In high-pT jet production the transverse region is very sensitive to the underlying event and is separated into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte-Carlo models. The goal of this analysis is to provide data that can be used to test and improve the QCD Monte-Carlo models of the underlying event that are used to simulate hadron-hadron collisions.Comment: Submitted to Phys.Rev.

Search for the Higgs boson in events with missing transverse energy and b quark jets produced in proton-antiproton collisions at s**(1/2)=1.96 TeV

We search for the standard model Higgs boson produced in association with an electroweak vector boson in events with no identified charged leptons, large imbalance in transverse momentum, and two jets where at least one contains a secondary vertex consistent with the decay of b hadrons. We use ~1 fb-1 integrated luminosity of proton-antiproton collisions at s**(1/2)=1.96 TeV recorded by the CDF II experiment at the Tevatron. We find 268 (16) single (double) b-tagged candidate events, where 248 +/- 43 (14.4 +/- 2.7) are expected from standard model background processes. We place 95% confidence level upper limits on the Higgs boson production cross section for several Higgs boson masses ranging from 110 GeV/c2 to 140 GeV/c2. For a mass of 115 GeV/c2 the observed (expected) limit is 20.4 (14.2) times the standard model prediction.Comment: 8 pages, 2 figures, submitted to Phys. Rev. Let