193 research outputs found
Quaternion Graph Neural Networks
Recently, graph neural networks (GNNs) become a principal research direction
to learn low-dimensional continuous embeddings of nodes and graphs to predict
node and graph labels, respectively. However, Euclidean embeddings have high
distortion when using GNNs to model complex graphs such as social networks.
Furthermore, existing GNNs are not very efficient with the high number of model
parameters when increasing the number of hidden layers. Therefore, we move
beyond the Euclidean space to a hyper-complex vector space to improve graph
representation quality and reduce the number of model parameters. To this end,
we propose quaternion graph neural networks (QGNN) to generalize GCNs within
the Quaternion space to learn quaternion embeddings for nodes and graphs. The
Quaternion space, a hyper-complex vector space, provides highly meaningful
computations through Hamilton product compared to the Euclidean and complex
vector spaces. As a result, our QGNN can reduce the model size up to four times
and enhance learning better graph representations. Experimental results show
that the proposed QGNN produces state-of-the-art accuracies on a range of
well-known benchmark datasets for three downstream tasks, including graph
classification, semi-supervised node classification, and text (node)
classification. Our code is available at: https://github.com/daiquocnguyen/QGNNComment: The extended abstract has been accepted to NeurIPS 2020 Workshop on
Differential Geometry meets Deep Learning (DiffGeo4DL). The code in Pytorch
and Tensorflow is available at: https://github.com/daiquocnguyen/QGN
Two-view Graph Neural Networks for Knowledge Graph Completion
We present an effective GNN-based knowledge graph embedding model, named WGE,
to capture entity- and relation-focused graph structures. In particular, given
the knowledge graph, WGE builds a single undirected entity-focused graph that
views entities as nodes. In addition, WGE also constructs another single
undirected graph from relation-focused constraints, which views entities and
relations as nodes. WGE then proposes a GNN-based architecture to better learn
vector representations of entities and relations from these two single entity-
and relation-focused graphs. WGE feeds the learned entity and relation
representations into a weighted score function to return the triple scores for
knowledge graph completion. Experimental results show that WGE outperforms
competitive baselines, obtaining state-of-the-art performances on seven
benchmark datasets for knowledge graph completion.Comment: 13 pages; 3 tables; 3 figure
Multiobjective Logistics Optimization for Automated ATM Cash Replenishment Process
In the digital transformation era, integrating digital technology into every
aspect of banking operations improves process automation, cost efficiency, and
service level improvement. Although logistics for ATM cash is a crucial task
that impacts operating costs and consumer satisfaction, there has been little
effort to enhance it. Specifically, in Vietnam, with a market of more than
20,000 ATMs nationally, research and technological solutions that can resolve
this issue remain scarce. In this paper, we generalized the vehicle routing
problem for ATM cash replenishment, suggested a mathematical model and then
offered a tool to evaluate various situations. When being evaluated on the
simulated dataset, our proposed model and method produced encouraging results
with the benefits of cutting ATM cash operating costs
Transport Jc in Bulk Superconductors: A Practical Approach?
The characterisation of the critical current density of bulk high temperature superconductors is typically performed using magnetometry, which involves numerous assumptions including, significantly, that Jc within the sample is uniform. Unfortunately, magnetometry is particularly challenging to apply where a local measurement of Jc across a feature, such as a grain boundary, is desired. Although transport measurements appear to be an attractive alternative to magnetization, it is extremely challenging to reduce the cross-sectional area of a bulk sample sufficiently to achieve a sufficiently low critical current that can be generated by a practical current source. In the work described here, we present a technique that enables transport measurements to be performed on sections of bulk superconductors. Metallographic techniques and resin reinforcement were used to create an I-shaped sample of bulk superconductor from a section of Gd-Ba-Cu-O containing 15 wt % Ag2O. The resulting superconducting track had a cross-sectional area of 0.44 mm2. The sample was found to support a critical current of 110 A using a field criterion in the narrowed track region of 1 μV cm-1. We conclude, therefore, that it is possible to measure critical current densities in excess of 2.5 x 108 A m-2 in sections of a bulk superconductor.This work was supported by the Engineering and Physical Sciences Research Council, via a Doctoral Training Award (grant number is EP/L504920/1) and funding from grant number EP/K02910X/1. This work was also supported by the Boeing Company. All data are provided in full in the results section of this paper.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/TASC.2016.253764
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