AVATAR - Machine Learning Pipeline Evaluation Using Surrogate Model

© 2020, The Author(s). The evaluation of machine learning (ML) pipelines is essential during automatic ML pipeline composition and optimisation. The previous methods such as Bayesian-based and genetic-based optimisation, which are implemented in Auto-Weka, Auto-sklearn and TPOT, evaluate pipelines by executing them. Therefore, the pipeline composition and optimisation of these methods requires a tremendous amount of time that prevents them from exploring complex pipelines to find better predictive models. To further explore this research challenge, we have conducted experiments showing that many of the generated pipelines are invalid, and it is unnecessary to execute them to find out whether they are good pipelines. To address this issue, we propose a novel method to evaluate the validity of ML pipelines using a surrogate model (AVATAR). The AVATAR enables to accelerate automatic ML pipeline composition and optimisation by quickly ignoring invalid pipelines. Our experiments show that the AVATAR is more efficient in evaluating complex pipelines in comparison with the traditional evaluation approaches requiring their execution

LIPIcs, Volume 277, GIScience 2023, Complete Volume

LIPIcs, Volume 277, GIScience 2023, Complete Volum

"Our Word is Our Weapon": Text-Analyzing Wars of Ideas from the French Revolution to the First World War

What are political thinkers doing with their words when they write a text, engage in a debate, or give a speech? We propose a "computational political theory", pairing recent breakthroughs in computational linguistics with the hermeneutic practices of intellectual history, as a set of tools for mapping out the political-discursive fields within which ideas circulate. We begin by showing, via a series of historical case studies, how a particular class of computational-linguistic algorithms called word embeddings are able to capture subtle differences in how authors employ certain contested terms (liberty, freedom, sovereignty, etc.) by explicitly modeling both the words and the contexts they're used in across a corpus of texts. We then demonstrate how the results of these embedding models can shed light on important questions in the history of political thought, by performing two in-depth studies of the origins and trajectories of Marxism from the 19th to the 20th century. In the first study, we use these models to trace the construction of Marx's thought out of the raw intellectual materials of 18th and early-19th century philosophy. We combine a new, comprehensive corpus of Marx's complete works from 1835 to 1883 ($N > 1200$) with a large sample ($N = 250$) of prominent 18th and early-19th century texts to measure conceptual distance between Marx's works and various schools of 19th-century thought (political economists, socialists, and Hegelian philosophers) over time. Two key breaks emerge in Marx's writings: (a) they become less Hegelian as he is exposed to Paris' brand of working-class-oriented socialism between 1843 and 1845, then (b) become more focused on issues of political economy over the remainder of his life in London, from 1849 onwards. Our second study turns from the origins to the illocutionary impacts of Marx's published works, assessing his influence on the broader socialist discourse of the 19th century using a corpus of \textit{post}-1850 socialist texts ($N = 200$). We find that Marx's semantic trajectory is mirrored, with a lag, by changes in the semantic trajectory of European socialist thought. This discourse shifts away from moralistic and Hegelian themes and towards a more positivistic political-economic vocabulary, especially after Marx's rise to public prominence in the wake of the 1871 Paris Commune. Our findings thus trace out, within the computationally-inferred ideological field of 19th-century socialist thought, how Marx's unique blend of German philosophy, French socialism, and British political economy defeated would-be competitors and established his thought as the default language of European socialism by the time of Engels' death in 1895. The dissertation thus demonstrates the utility of modern context-sensitive language models as tools for historical research, providing a framework for their use in developing, testing, and revising our understandings of key questions in the history of political thought

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion

The magmatic crust of Vesta

Les astéroïdes Cérès et Vesta ont motivé la mission spatiale Dawn parce qu'ils représentent deux embryons planétaires différents restés relativement intacts depuis leur formation. Vesta est large- ment considéré comme le corps parent des météorites HED témoins d'une activité magmatique probablement due à la présence de l'isotope radioactif 26Al qui était suffisamment abondant pour permettre la fusion interne des corps rocheux primitifs. La composition d'une surface planétaire peut être mesurée grâce à l'analyse des rayons gammas qu'elle produit. Pour la sonde Dawn cela est rendu possible par l'instrument GRaND et la scintillation d'un cristal de BGO. Cette thèse présente l'analyse des spectres gammas de Vesta par deux outils de séparation aveugle de source: l'analyse en composantes indépendantes (ICA) et la factorisation en matrice non-négative (NMF). Ces méthodes sont aussi appliquées à un jeu de données lunaire comparable et déjà bien interprété. Des spectres synthétiques lunaires permettent de tester ICA et NMF. La séparation de spectres élémentaires s'avère délicate même si on peut distinguer les éléments K, Th et Fe en raison des propriétés statistiques de leur signaux sources plus favorables. On mesure la sensibilité d'ICA-NMF à la variabilité chimique de la surface pour des Lunes artificielles, ce qui permet d'expliquer l'absence de séparation d'un signal élémentaire clair dans le cas de Vesta. Malgré les observations de la sonde Dawn et le nombre important d'informations fournies par les HED, il n'y a pas de consensus sur la formation des HED. On met souvent en avant l'existence d'un océan magmatique global sur Vesta, alors que la migration de la principale source chaleur, contenue dans le premier minéral fondu, le plagioclase, ne permet pas la fusion totale. On met en oeuvre un modèle de migration des magmas, basé sur les équations de la compaction. On adapte ce modèle en utilisant un diagramme d'équilibre de phase olivine-anorthite-quartz. Cela permet de calculer l'évolution de la minéralogie en fonction du temps et de la profondeur. Les résultats montrent que les eucrites et les diogénites pourraient être une caractéristique commune des gros corps accrétés tôt dans l'histoire du système solaire.Asteroids Vesta and Ceres motivated the space mission Dawn because they represent two different planetary embryos that remained relatively intact since their formation. Vesta is broadly considered as the parent body of the HED meteorites suite that are witnesses of a magmatic activity probably due to the presence of the radioactive isotope 26 Al which was present in significant amount to cause internal melting of primitive rocky bodies. The composition of a planetary surface can be quantified through the analysis of the gamma rays it produces. This is made possible for the Dawn spacecraft by the instrument GRaND and the scintillation of a BGO crystal. This thesis presents the analysis of gamma ray spectra from Vesta by two blind source separation methods: the independent component analysis and the non negative matrix factorization. These methods are also applied to an equivalent lunar dataset already well interpreted. Lunar synthetic spectra are used to test ICA and NMF. The separation of elementary spectra is delicate although K, Th and Fe can be discriminated due to the more favorable statistical properties of their source signals. The sensitivity of separation to the chemical variability is assessed based on artificial lunar spectra, which allows to explain the lack of separation of a clear elemental signal in the case of Vesta. Despite the observations of Dawn and the important collection of HED data, there is no consensus on the conditions of the vestan magmatism. A global magma ocean is often put forward, whereas the migration of the heat source, contained in the easiest mineral to melt, plagioclase, does not allow it. A model of melt migration is implemented, based on two-phase flow equations. This model is combined with the olivine-anorthite-quartz equilibrium phase diagram. This allows to predict the mineralogy as a function of depth and time. Results obtained show that eucrites and diogenites may be a common feature of large bodies accreted early in solar system history

19th Conference of The Associations of Christians In The Mathematical Sciences

Association of Christians in the Mathematical Sciences 19th Biennial Conference Proceedings, May 29 - June 1, 2011, Bethel University