179 research outputs found
Solar Wind Speed Estimate with Machine Learning Ensemble Models for LISA
In this work we study the potentialities of machine learning models in
reconstructing the solar wind speed observations gathered in the first
Lagrangian point by the ACE satellite in 2016--2017 using as input data
galactic cosmic-ray flux variations measured with particle detectors hosted
onboard the LISA Pathfinder mission also orbiting around L1 during the same
years. We show that ensemble models composed of heterogeneous weak regressors
are able to outperform weak regressors in terms of predictive accuracy. Machine
learning and other powerful predictive algorithms open a window on the
possibility of substituting dedicated instrumentation with software models
acting as surrogates for diagnostics of space missions such as LISA and space
weather science.Comment: Submitted to Environmental Modelling & Softwar
First record in Cyprus of Cinara (Cinara) cedri Mimeur (Aphididae Lachninae) on Cedrus brevifolia (Hooker fil.) Henry.
The Authors report on the discovery in South Cyprus of the aphid Cinara (Cinara) cedri Mimeur collected on the endemic cedar, Cedrus brevifolia (Hooker fil.) Henry. This is the first record of the lacnid in Cyprus. The ecological aspects of the cedar and its interaction with the related aphid species are discussed. The Authors suggest the hypothesis that the aphid may be co-endemic with its host conifer since it shows significant morphological differences compared with specimens from other European regions. The question whether the Cyprus cedar aphid can be injurious or not to its host plant is debated as well. The exact taxonomic position of this lacnid is currently under investigation
Hypercube-Based Methods for Symbolic Knowledge Extraction: Towards a Unified Model
Symbolic knowledge-extraction (SKE) algorithms proposed by the XAI community to obtain human-intelligible explanations for opaque machine learning predictors are currently being studied and developed with growing interest, also in order to achieve believability in interactions. However, choosing the most adequate extraction procedure amongst the many existing in the literature is becoming more and more challenging, as the amount of available methods increases. In fact, most of the proposed algorithms come with constraints over their applicability.
In this paper we focus upon a quite general class of SKE techniques, namely hypercube-based methods. Despite being commonly considered regression-specific, we discuss why hypercube-based SKE methods are flexible enough to deal with classification problems as well. More generally, we propose a common generalised model for hypercube-based methods, and we show how they can be exploited to perform SKE on datasets, predictors, or learning tasks of any sort. We also report as a concrete example the implementation of the proposed generalisation in the PSyKE framework
Towards a unified model for symbolic knowledge extraction with hypercube-based methods
The XAI community is currently studying and developing symbolic knowledge-extraction (SKE) algorithms as a means to produce human-intelligible explanations for black-box machine learning predictors, so as to achieve believability in human-machine interaction. However, many extraction procedures exist in the literature, and choosing the most adequate one is increasingly cumbersome, as novel methods keep on emerging. Challenges arise from the fact that SKE algorithms are commonly defined based on theoretical assumptions that typically hinder practical applicability.
This paper focuses on hypercube-based SKE methods, a quite general class of extraction techniques mostly devoted to regression-specific tasks. We first show that hypercube-based methods are flexible enough to support classification problems as well, then we propose a general model for them, and discuss how they support SKE on datasets, predictors, or learning tasks of any sort. Empirical examples are reported as well – based upon the PSyKE framework –, showing the applicability of hypercube-based methods to actual classification tasks
Bridging the gap between Monte Carlo simulations and measurements of the LISA Pathfinder test-mass charging for LISA
Cubic gold-platinum free-falling test masses (TMs) constitute the mirrors of
future LISA and LISA-like interferometers for low-frequency gravitational wave
detection in space. High-energy particles of Galactic and solar origin charge
the TMs and thus induce spurious electrostatic and magnetic forces that limit
the sensitivity of these interferometers. Prelaunch Monte Carlo simulations of
the TM charging were carried out for the LISA Pathfinder (LPF) mission, that
was planned to test the LISA instrumentation. Measurements and simulations were
compared during the mission operations. The measured net TM charging agreed
with simulation estimates, while the charging noise was three to four times
higher. We aim to bridge the gap between LPF TM charging noise simulations and
observations. New Monte Carlo simulations of the LPF TM charging due to both
Galactic and solar particles were carried out with the FLUKA/LEI toolkit. This
allowed propagating low-energy electrons down to a few electronvolt. These
improved FLUKA/LEI simulations agree with observations gathered during the
mission operations within statistical and Monte Carlo errors. The charging
noise induced by Galactic cosmic rays is about one thousand charges per second.
This value increases to tens of thousands charges per second during solar
energetic particle events. Similar results are expected for the LISA TM
charging.Comment: 11 pages, 9 figure
A RANDOMIZED, DOUBLE-BLIND, CROSS-OVER STUDY COMPARING A LEVOSULPIRIDE-BASED AND A METOCLOPRAMIDE-BASED COMBINATION IN THE PREVENTION OF PROMECE-CYTABOM-INDUCED EMESIS
Background. To test two different antiemetic regimens for preventing nausea and vomiting in patients with non-Hodgkin's lymphoma (NHL) undergoing systemic chemotherapy (CT) with ProMECE-CytaBOM (P-C). Patients and Methods. Twenty consecutive untreated adult outpatients with histologically confirmed NHL and scheduled to receive P-C chemotherapy were registered in a randomized, double-blind, cross-over study to compare the antiemetic efficacy of a levosulpiride (LS)-based and metoclopramide (MTC)-based regimen. Results. Complete protection from vomiting was recorded in 93% (62/67) of courses with the LS-regimen and in 89% (62/70) with the MTC-regimen (p = 0.428). No nausea was observed in 84% (56/67) of courses with the LS-regimen and in 74% (52/70) with the MTC-regimen (p = 0.183). No differences in prevention of emesis were recorded when patients crossed to the other regimen. Both regimens were well tolerated; however, on day 8 of chemotherapy, when both antiemetic regimens were administered at a higher dose, the LS-based combination showed significantly lower toxicity (p = 0.035). Conclusions. ProMECE-CytaBOM-induced emesis can be prevented in most cases with appropriate, specifically designed antiemetic therapy. Both the LS- and MTC-based combinations resulted in a high percentage of complete protection from emesis, but the higher incidence of side effects observed with MTC makes the LS-based regimen preferable for patients receiving P-C chemotherapy
Anoplophora chinensis (Forster) (Coleoptera Cerambycidae) in the outbreak site in Rome (Italy): experiences in dating exit holes
Anoplophora chinensis is a poliphagous woodboring beetle native to Eastern Asia, and is a serious pest accidentally introduced into Europe. Currently two infested areas are present in Italy and other infestations have occurred in the past in other European countries, while interceptions in entry ports are made yearly by National Plant Protection Organizations of the European Community. A. chinensis is a quarantine invasive pest, and strong measures are applied worldwide to prevent its introduction, spread and to eradicate its populations. The presence of exit holes of adult beetles on infested trees is one of the most important diagnostic signs to detect an A. chinensis infestation. Exit holes are visible on the bark surface of infested trees for several years, but the hole is after that enclosed by the reaction tissue (callus) of the plant; thus, after some years the exit hole is no longer visible. Such injuries produced by beetle activity can be recognised after many years by inspection of the wood after cross-sectioning of the tree. It is possible to date the time of occurrence of the injury using the annual growth ring method for tree age analyses. Surveys conducted on the wooden material collected in the infested site in Rome indicate that the first A. chinensis adult emergences from infested trees of the city occurred in 2002. Since the species takes in the infested site 1 or 2 years for juvenile development, we can speculate that the first introduction of A. chinensis into the city of Rome took place in the years 2000 or 2001
Gamasid soil mites (Arachnida Acari) as indicators of the conservation status of forests
The Gamasida of 8 study areas in 5 different Sites of Community Interest (SCI of the Nature 2000 network) of Central Italy, characterized by beech forest and by mixed forests, were investigated to collect information for define the conservation status of the investigated sites. Samples were taken in autumn from the forest ground of the study sites (litter and soil till 7 cm in depth) during the three years of the study. Collected adult specimens were identified at species level and data were used to calculate the following indices: Shannon, Simpson, Eveness and Maturity index. On the whole, in the 8 study sites were recorded 63 species of Gamasida, belonging to 17 families, and some species seems to be a rare component of the fauna. Among study sites, diversity indices ranged from 2.20 to 2.57 for the Shannon index and from 0.82 to 0.90 for the Simpson, while the Maturity index ranged from 0.69 to 0.85; no substantial differences were observed among different study areas
An effective method for Graphosoma lineatum (L.) long-term rearing.
A simple and time-saving technique for an effective and continuous rearing of Graphosoma lineatum (L.) (Heteroptera Pentatomidae), an alternative host for Trissolcus spp. and Ooencyrtus spp. production, was set for entomological research and maintained for a long period. Insects were maintained in containers as rearing units; 100x35x35cm cages hosted adults; 40x30x30cm cages hosted nymphs. Graphosoma lineatum was fed on seeds of Foeniculum vulgare Mill., Anethum graveolens L. and Pimpinella anisum L. Moreover, potted young plants of F. vulgare were also used as additional food source. Water for insects and plants was provided by small automatic irrigation systems. When each colony cage reached the density of 100 adult couples, the number of oviposited batches was followed up for 12 weeks. Batches laid per cage were approximately one hundred per week. Therefore the overall weekly production of six adult cages was about 8400 eggs. This technique was plain and cost effective, allowing a constant egg production throughout the year.
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