1,720,976 research outputs found
Explainability in subgraphs-enhanced Graph Neural Networks
Full text linkRecently, subgraphs-enhanced Graph Neural Networks (SGNNs) have been
introduced to enhance the expressive power of Graph Neural Networks (GNNs),
which was proved to be not higher than the 1-dimensional Weisfeiler-Leman
isomorphism test. The new paradigm suggests using subgraphs extracted from the
input graph to improve the model's expressiveness, but the additional
complexity exacerbates an already challenging problem in GNNs: explaining their
predictions. In this work, we adapt PGExplainer, one of the most recent
explainers for GNNs, to SGNNs. The proposed explainer accounts for the
contribution of all the different subgraphs and can produce a meaningful
explanation that humans can interpret. The experiments that we performed both
on real and synthetic datasets show that our framework is successful in
explaining the decision process of an SGNN on graph classification tasks.Comment: The source code implementing our workflow is publicly available
online at https://github.com/MicheleUIT/Explaining_SGN
FairDrop: Biased Edge Dropout for Enhancing Fairness in Graph Representation Learning
Full text linkGraph representation learning has become a ubiquitous component in many
scenarios, ranging from social network analysis to energy forecasting in smart
grids. In several applications, ensuring the fairness of the node (or graph)
representations with respect to some protected attributes is crucial for their
correct deployment. Yet, fairness in graph deep learning remains
under-explored, with few solutions available. In particular, the tendency of
similar nodes to cluster on several real-world graphs (i.e., homophily) can
dramatically worsen the fairness of these procedures. In this paper, we propose
a novel biased edge dropout algorithm (FairDrop) to counter-act homophily and
improve fairness in graph representation learning. FairDrop can be plugged in
easily on many existing algorithms, is efficient, adaptable, and can be
combined with other fairness-inducing solutions. After describing the general
algorithm, we demonstrate its application on two benchmark tasks, specifically,
as a random walk model for producing node embeddings, and to a graph
convolutional network for link prediction. We prove that the proposed algorithm
can successfully improve the fairness of all models up to a small or negligible
drop in accuracy, and compares favourably with existing state-of-the-art
solutions. In an ablation study, we demonstrate that our algorithm can flexibly
interpolate between biasing towards fairness and an unbiased edge dropout.
Furthermore, to better evaluate the gains, we propose a new dyadic group
definition to measure the bias of a link prediction task when paired with
group-based fairness metrics. In particular, we extend the metric used to
measure the bias in the node embeddings to take into account the graph
structure.Comment: Submitted to a journal for the peer-review proces
Combining stochastic explainers and subgraph neural networks can increase expressivity and interpretability
Full text linkSubgraph-enhanced graph neural networks (SGNN) can increase the expressive power of the standard message-passing framework. This model family represents each graph as a collection of subgraphs, generally extracted by random sampling or with hand-crafted heuristics. Our key observation is that by selecting "meaningful" subgraphs, besides improving the expressivity of a GNN, it is also possible to obtain interpretable results. For this purpose, we introduce a novel framework that jointly predicts the class of the graph and a set of explanatory sparse subgraphs, which can be analyzed to understand the decision process of the classifier. The subgraphs produced by our framework allow to achieve comparable performance in terms of accuracy, with the additional benefit of providing explanations
Spatio-temporal transformers for decoding neural movement control
No full textObjective. Deep learning tools applied to high-resolution neurophysiological data have significantly progressed, offering enhanced decoding, real-time processing, and readability for practical applications. However, the design of artificial neural networks to analyze neural activityin vivoremains a challenge, requiring a delicate balance between efficiency in low-data regimes and the interpretability of the results.Approach. To address this challenge, we introduce a novel specialized transformer architecture to analyze single-neuron spiking activity. The model is tested on multi-electrode recordings from the dorsal premotor cortex of non-human primates performing a motor inhibition task.Main results. The proposed architecture provides an early prediction of the correct movement direction, achieving accurate results no later than 230 ms after the Go signal presentation across animals. Additionally, the model can forecast whether the movement will be generated or withheld before a stop signal, unattended, is actually presented. To further understand the internal dynamics of the model, we compute the predicted correlations between time steps and between neurons at successive layers of the architecture, with the evolution of these correlations mirrors findings from previous theoretical analyses.Significance. Overall, our framework provides a comprehensive use case for the practical implementation of deep learning tools in motor control research, highlighting both the predictive capabilities and interpretability of the proposed architecture
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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