SemTab 2019: Resources to Benchmark Tabular Data to Knowledge Graph Matching Systems

Tabular data to Knowledge Graph matching is the process of assigning semantic tags from knowledge graphs (e.g., Wikidata or DBpedia) to the elements of a table. This task is a challenging problem for various reasons, including the lack of metadata (e.g., table and column names), the noisiness, heterogeneity, incompleteness and ambiguity in the data. The results of this task provide significant insights about potentially highly valuable tabular data, as recent works have shown, enabling a new family of data analytics and data science applications. Despite significant amount of work on various flavors of this problem, there is a lack of a common framework to conduct a systematic evaluation of state-of-the-art systems. The creation of the Semantic Web Challenge on Tabular Data to Knowledge Graph Matching (SemTab) aims at filling this gap. In this paper, we report about the datasets, infrastructure and lessons learned from the first edition of the SemTab challenge

Tough Tables: Carefully Evaluating Entity Linking for Tabular Data

Table annotation is a key task to improve querying the Web and support the Knowledge Graph population from legacy sources (tables). Last year, the SemTab challenge was introduced to unify different efforts to evaluate table annotation algorithms by providing a common interface and several general-purpose datasets as a ground truth. The SemTab dataset is useful to have a general understanding of how these algorithms work, and the organizers of the challenge included some artificial noise to the data to make the annotation trickier. However, it is hard to analyze specific aspects in an automatic way. For example, the ambiguity of names at the entity-level can largely affect the quality of the annotation. In this paper, we propose a novel dataset to complement the datasets proposed by SemTab. The dataset consists of a set of high-quality manually-curated tables with non-obviously linkable cells, i.e., where values are ambiguous names, typos, and misspelled entity names not appearing in the current version of the SemTab dataset. These challenges are particularly relevant for the ingestion of structured legacy sources into existing knowledge graphs. Evaluations run on this dataset show that ambiguity is a key problem for entity linking algorithms and encourage a promising direction for future work in the field

Teachers reflecting on teaching global issues: “Because I’m also part of the problem”

The paper draws on literature in Global Education (GE) and its relevance to the work of teachers. Having been inspired by Paulo Freire, teachers’ voices are being considered in relation to the teaching of global issues. A Participatory Action Research approach was adopted as part of which photovoice was used. Findings demonstrate teachers’ perceptions of global issues, as well as ways of interpreting and making sense of globalization. The latter is perceived within a framework of dichotomies of globalization and anti-globalization. Through collective discussion, teachers labeled themselves complicit to existing global issues. As such, we suggest that teachers’ educational wisdom on teaching about global issues seems to align to postcolonial approaches within GE. Therefore, we argue that teachers’ voices offer insightful perspectives for perceptions and conceptualizations of Global Education. -- Resumo: O artigo baseia-se na literatura em Educação Global (GE) e sua relevância para o trabalho dos professores. Tendo se inspirado em Paulo Freire, as vozes dos professores são aqui consideradas em relação ao ensino de questões globais. Numa abordagem de investigação-ação, utilizou-se a ferramenta metodológica photovoice. Os resultados demonstram as percepções dos docentes sobre as questões globais, bem como as formas de interpretar e compreender a globalização. Esta última é percebida dentro de uma estrutura binária de globalização e antiglobalização. Por meio da discussão coletiva, os professores autodenominaram-se cúmplices das questões globais existentes. Como tal, sugerimos que o conhecimento dos docentes sobre o ensino de questões globais parece alinhar-se com as abordagens pós-coloniais dentro da GE. Argumentamos, por isso, que as vozes dos professores oferecem perspectivas interessantes e geradoras de debate para as percepções e conceptualizações em relação à Educação Global. -- Resumen: El documento se basa en la literatura sobre Educación Global (GE) y su relevancia para el trabajo de los docentes. Inspirándose en Paulo Freire, las voces de los profesores se están considerando en relación con la enseñanza de temas globales. Se adoptó un enfoque de investigación-acción, como parte del cual se utilizó la foto-voz. Los resultados demuestran las percepciones de los profesores sobre los problemas globales, así como las formas de interpretar y dar sentido a la globalización. Esto último se percibe dentro de un marco binario de globalización y antiglobalización. A través de la discusión colectiva, los profesores se etiquetan a sí mismos como cómplices de los problemas globales existentes. Como tal, sugerimos que la sabiduría educativa de los docentes sobre la enseñanza de temas globales parece alinearse con los enfoques poscoloniales dentro de GE. Por lo tanto, argumentamos que las voces de los docentes ofrecen perspectivas perspicaces para las percepciones y conceptualizaciones de la Educación Global.https://sinergiased.org/wp-content/uploads/2022/02/Teachers-reflecting-on-teaching-global-issues-Because-Im-also-part-of-the-problem.pd

Mononuclear and Dinuclear Manganese(II) Complexes from the Use of Methyl(2-pyridyl)ketone Oxime

The reactions of methyl(2-pyridyl)ketone oxime, (py)C(Me)NOH, with manganese(II) sulfate monohydrate have been investigated. The reaction between equimolar quantities of MnSO4 · H2O and (py)C(Me)NOH in H2O lead to the dinuclear complex [Mn2(SO4)2{(py)C(Me)NOH}4] · (py)C(Me)NOH, 1 · (py)C(Me)NOH, while employment of NaOMe as base affords the compound [Mn(HCO2)2{(py)C(Me)NOH}2] (2). The structures of both compounds have been determined by single crystal X-ray diffraction. In both complexes, the organic ligand chelates through its nitrogen atoms. The IR data are discussed in terms of the nature of bonding and the structures of the two complexes

Random sampling of colourings of sparse random graphs with a constant number of colours

In this work we present a simple and efficient algorithm which, with high probability, provides an almost uniform sample from the set of proper k-colourings on an instance of a sparse random graph G(n,d/n), where k=k(d) is a sufficiently large constant. Our algorithm is not based on the Markov Chain Monte Carlo method (M.C.M.C.). Instead, we provide a novel proof of correctness of our Algorithm that is based on interesting "spatial mixing" properties of colourings of G(n,d/n). Our result improves upon previous results (based on M.C.M.C.) that required a number of colours growing unboundedly with n.Comment: 30 pages 0 figures, uses fullpage.st

On the source of oscillatory behaviour during switching of power enhancement mode GaN HEMTs

© 2017 by the author. With Gallium Nitride (GaN) device technology for power electronics applications being ramped up for volume production, an increasing amount of research is now focused on the performance of GaN power devices in circuits. In this study, an enhancement mode GaN high electron mobility transistor (HEMT) is switched in a clamped inductive switching configuration with the aim of investigating the source of oscillatory effects observed. These arise as a result of the increased switching speed capability of GaN devices compared to their silicon counterparts. The study identifies the two major mechanisms (Miller capacitance charge and parasitic common source inductance) that can lead to ringing behaviour during turn-off and considers the effect of temperature on the latter. Furthermore, the experimental results are backed by SPICE modelling to evaluate the contribution of different circuit components to oscillations. The study concludes with good design techniques that can suppress the effects discussed