77 research outputs found
The Widths of Strict Outerconfluent Graphs
Strict outerconfluent drawing is a style of graph drawing in which vertices
are drawn on the boundary of a disk, adjacencies are indicated by the existence
of smooth curves through a system of tracks within the disk, and no two
adjacent vertices are connected by more than one of these smooth tracks. We
investigate graph width parameters on the graphs that have drawings in this
style. We prove that the clique-width of these graphs is unbounded, but their
twin-width is bounded.Comment: 15 pages, 2 figure
Algorithms and Bounds for Drawing Directed Graphs
In this paper we present a new approach to visualize directed graphs and
their hierarchies that completely departs from the classical four-phase
framework of Sugiyama and computes readable hierarchical visualizations that
contain the complete reachability information of a graph. Additionally, our
approach has the advantage that only the necessary edges are drawn in the
drawing, thus reducing the visual complexity of the resulting drawing.
Furthermore, most problems involved in our framework require only polynomial
time. Our framework offers a suite of solutions depending upon the
requirements, and it consists of only two steps: (a) the cycle removal step (if
the graph contains cycles) and (b) the channel decomposition and hierarchical
drawing step. Our framework does not introduce any dummy vertices and it keeps
the vertices of a channel vertically aligned. The time complexity of the main
drawing algorithms of our framework is , where is the number of
channels, typically much smaller than (the number of vertices).Comment: Appears in the Proceedings of the 26th International Symposium on
Graph Drawing and Network Visualization (GD 2018
DiscoverPath: A Knowledge Refinement and Retrieval System for Interdisciplinarity on Biomedical Research
The exponential growth in scholarly publications necessitates advanced tools
for efficient article retrieval, especially in interdisciplinary fields where
diverse terminologies are used to describe similar research. Traditional
keyword-based search engines often fall short in assisting users who may not be
familiar with specific terminologies. To address this, we present a knowledge
graph-based paper search engine for biomedical research to enhance the user
experience in discovering relevant queries and articles. The system, dubbed
DiscoverPath, employs Named Entity Recognition (NER) and part-of-speech (POS)
tagging to extract terminologies and relationships from article abstracts to
create a KG. To reduce information overload, DiscoverPath presents users with a
focused subgraph containing the queried entity and its neighboring nodes and
incorporates a query recommendation system, enabling users to iteratively
refine their queries. The system is equipped with an accessible Graphical User
Interface that provides an intuitive visualization of the KG, query
recommendations, and detailed article information, enabling efficient article
retrieval, thus fostering interdisciplinary knowledge exploration. DiscoverPath
is open-sourced at https://github.com/ynchuang/DiscoverPath
Graph Algorithms and Applications
The mixture of data in real-life exhibits structure or connection property in nature. Typical data include biological data, communication network data, image data, etc. Graphs provide a natural way to represent and analyze these types of data and their relationships. Unfortunately, the related algorithms usually suffer from high computational complexity, since some of these problems are NP-hard. Therefore, in recent years, many graph models and optimization algorithms have been proposed to achieve a better balance between efficacy and efficiency. This book contains some papers reporting recent achievements regarding graph models, algorithms, and applications to problems in the real world, with some focus on optimization and computational complexity
Helmholtz Portfolio Theme Large-Scale Data Management and Analysis (LSDMA)
The Helmholtz Association funded the "Large-Scale Data Management and Analysis" portfolio theme from 2012-2016. Four Helmholtz centres, six universities and another research institution in Germany joined to enable data-intensive science by optimising data life cycles in selected scientific communities. In our Data Life cycle Labs, data experts performed joint R&D together with scientific communities. The Data Services Integration Team focused on generic solutions applied by several communities
Identifying Changes of Functional Brain Networks using Graph Theory
This thesis gives an overview on how to estimate changes in functional brain networks using graph theoretical measures. It explains the assessment and definition of functional brain networks derived from fMRI data. More explicitly, this thesis provides examples and newly developed methods on the measurement and visualization of changes due to pathology, external electrical stimulation or ongoing internal thought processes. These changes can occur on long as well as on short time scales and might be a key to understanding brain pathologies and their development. Furthermore, this thesis describes new methods to investigate and visualize these changes on both time scales and provides a more complete picture of the brain as a dynamic and constantly changing network.:1 Introduction
1.1 General Introduction
1.2 Functional Magnetic Resonance Imaging
1.3 Resting-state fMRI
1.4 Brain Networks and Graph Theory
1.5 White-Matter Lesions and Small Vessel Disease
1.6 Transcranial Direct Current Stimulation
1.7 Dynamic Functional Connectivity
2 Publications
2.1 Resting developments: a review of fMRI post-processing methodologies for
spontaneous brain activity
2.2 Early small vessel disease affects fronto-parietal and cerebellar hubs in close
correlation with clinical symptoms - A resting-state fMRI study
2.3 Dynamic modulation of intrinsic functional connectivity by transcranial direct current stimulation
2.4 Three-dimensional mean-shift edge bundling for the visualization of functional
connectivity in the brain
2.5 Dynamic network participation of functional connectivity hubs assessed by resting-state fMRI
3 Summary
4 Bibliography
5. Appendix
5.1 Erklärung über die eigenständige Abfassung der Arbeit
5.2 Curriculum vitae
5.3 Publications
5.4 Acknowledgement
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