intro.bib

@inproceedings{shneiderman_eyes_1996,
	title = {The eyes have it: a task by data type taxonomy for information visualizations},
	shorttitle = {The eyes have it},
	doi = {10.1109/VL.1996.545307},
	abstract = {A useful starting point for designing advanced graphical user interfaces is the visual information seeking Mantra: overview first, zoom and filter, then details on demand. But this is only a starting point in trying to understand the rich and varied set of information visualizations that have been proposed in recent years. The paper offers a task by data type taxonomy with seven data types (one, two, three dimensional data, temporal and multi dimensional data, and tree and network data) and seven tasks (overview, zoom, filter, details-on-demand, relate, history, and extracts).},
	booktitle = {Proceedings 1996 {IEEE} {Symposium} on {Visual} {Languages}},
	author = {Shneiderman, B.},
	month = sep,
	year = {1996},
	note = {ISSN: 1049-2615},
	keywords = {advanced graphical user interface design, Art, Data mining, data type taxonomy, data visualisation, Data visualization, Displays, Eyes, graphical user interfaces, Information filtering, Information filters, information visualizations, multi dimensional data, Multimedia databases, network data, Taxonomy, Visual databases, visual information seeking, visual programming},
	pages = {336--343}
}

@inproceedings{brath_3d_2014,
	title = {{3D} {InfoVis} is here to stay: {Deal} with it},
	shorttitle = {{3D} {InfoVis} is here to stay},
	doi = {10.1109/3DVis.2014.7160096},
	abstract = {3D information visualization has existed for more than 100 years. 3D offers intrinsic attributes such as an extra dimension for encoding position and length, meshes and surfaces; lighting and separation. Further 3D can aid mental models for configuration of data within a 3D spatial framework. Perceived issues with 3D are solvable and successful, specialized information visualizations can be built.},
	booktitle = {2014 {IEEE} {VIS} {International} {Workshop} on {3DVis} ({3DVis})},
	author = {Brath, Richard},
	month = nov,
	year = {2014},
	keywords = {data visualisation, Data visualization, graphical user interfaces, Navigation, Visualization, Encoding, Three-dimensional displays, 3D information visualization, 3D Information Visualization, 3D InfoVis, 3D spatial framework, Bars, Correlation, mental models, visual databases},
	pages = {25--31},
}

@article{zhou_human_2014,
	title = {Human symptoms–disease network},
	volume = {5},
	copyright = {2014 Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
	issn = {2041-1723},
	url = {https://www.nature.com/articles/ncomms5212},
	doi = {10.1038/ncomms5212},
	abstract = {In the post-genomic era, the elucidation of the relationship between the molecular origins of diseases and their resulting phenotypes is a crucial task for medical research. Here, we use a large-scale biomedical literature database to construct a symptom-based human disease network and investigate the connection between clinical manifestations of diseases and their underlying molecular interactions. We find that the symptom-based similarity of two diseases correlates strongly with the number of shared genetic associations and the extent to which their associated proteins interact. Moreover, the diversity of the clinical manifestations of a disease can be related to the connectivity patterns of the underlying protein interaction network. The comprehensive, high-quality map of disease–symptom relations can further be used as a resource helping to address important questions in the field of systems medicine, for example, the identification of unexpected associations between diseases, disease etiology research or drug design.},
	language = {en},
	number = {1},
	urldate = {2020-12-18},
	journal = {Nature Communications},
	author = {Zhou, XueZhong and Menche, Jörg and Barabási, Albert-László and Sharma, Amitabh},
	month = jun,
	year = {2014},
	note = {Publisher: Nature Publishing Group},
	pages = {4212}
}

@article{kraus_impact_2020,
	title = {The {Impact} of {Immersion} on {Cluster} {Identification} {Tasks}},
	volume = {26},
	issn = {1941-0506},
	doi = {10.1109/TVCG.2019.2934395},
	abstract = {Recent developments in technology encourage the use of head-mounted displays (HMDs) as a medium to explore visualizations in virtual realities (VRs). VR environments (VREs) enable new, more immersive visualization design spaces compared to traditional computer screens. Previous studies in different domains, such as medicine, psychology, and geology, report a positive effect of immersion, e.g., on learning performance or phobia treatment effectiveness. Our work presented in this paper assesses the applicability of those findings to a common task from the information visualization (InfoVis) domain. We conducted a quantitative user study to investigate the impact of immersion on cluster identification tasks in scatterplot visualizations. The main experiment was carried out with 18 participants in a within-subjects setting using four different visualizations, (1) a 2D scatterplot matrix on a screen, (2) a 3D scatterplot on a screen, (3) a 3D scatterplot miniature in a VRE and (4) a fully immersive 3D scatterplot in a VRE. The four visualization design spaces vary in their level of immersion, as shown in a supplementary study. The results of our main study indicate that task performance differs between the investigated visualization design spaces in terms of accuracy, efficiency, memorability, sense of orientation, and user preference. In particular, the 2D visualization on the screen performed worse compared to the 3D visualizations with regard to the measured variables. The study shows that an increased level of immersion can be a substantial benefit in the context of 3D data and cluster detection.},
	number = {1},
	journal = {IEEE Transactions on Visualization and Computer Graphics},
	author = {Kraus, M. and Weiler, N. and Oelke, D. and Kehrer, J. and Keim, D. A. and Fuchs, J.},
	month = jan,
	year = {2020},
	keywords = {virtual reality, data visualisation, Data visualization, Visualization, Three-dimensional displays, Two dimensional displays, evaluation, Task analysis, 2D scatterplot matrix, 3D scatterplot miniature, cluster detection, cluster identification tasks, clustering, Dimensionality reduction, fully immersive 3D scatterplot, head-mounted displays, helmet mounted displays, immersive visualization design spaces, information visualization domain, InfoVis domain, learning performance, pattern clustering, scatterplot visualizations, virtual realities, Virtual reality, visual analytics, visualization design spaces, VR environments, VRE},
	pages = {525--535}
}

@article{bowman_virtual_2007,
	title = {Virtual {Reality}: {How} {Much} {Immersion} {Is} {Enough}?},
	volume = {40},
	issn = {1558-0814},
	shorttitle = {Virtual {Reality}},
	doi = {10.1109/MC.2007.257},
	abstract = {Solid evidence of virtual reality's benefits has graduated from impressive visual demonstrations to producing results in practical applications. Further, a realistic experience is no longer immersion's sole asset. Empirical studies show that various components of immersion provide other benefits - full immersion is not always necessary. The goal of immersive virtual environments (VEs) was to let the user experience a computer-generated world as if it were real - producing a sense of presence, or "being there," in the user's mind.},
	number = {7},
	journal = {Computer},
	author = {Bowman, D. A. and McMahan, R. P.},
	month = jul,
	year = {2007},
	keywords = {virtual reality, Application software, data visualisation, data visualization, Virtual reality, 3D visualization, Cities and towns, Clinical trials, computer-generated world, Conference management, Costs, immersion, immersive virtual environment, Management training, Medical treatment, Military computing, Public speaking},
	pages = {36--43}
}

@book{yang_embodied_2020,
	title = {Embodied {Navigation} in {Immersive} {Abstract} {Data} {Visualization}: {Is} {Overview}+{Detail} or {Zooming} {Better} for {3D} {Scatterplots}?},
	shorttitle = {Embodied {Navigation} in {Immersive} {Abstract} {Data} {Visualization}},
	abstract = {data has no natural scale and so interactive data visualizations must provide techniques to allow the user to choose their viewpoint and scale. Such techniques are well established in desktop visualization tools. The two most common techniques are zoom+pan and overview+detail. However, how best to enable the analyst to navigate and view abstract data at different levels of scale in immersive environments has not previously been studied. We report the findings of the first systematic study of immersive navigation techniques for 3D scatterplots. We tested four conditions that represent our best attempt to adapt standard 2D navigation techniques to data visualization in an immersive environment while still providing standard immersive navigation techniques through physical movement and teleportation. We compared room-sized visualization versus a zooming interface, each with and without an overview. We find significant differences in participants' response times and accuracy for a number of standard visual analysis tasks. Both zoom and overview provide benefits over standard locomotion support alone (i.e., physical movement and pointer teleportation). However, which variation is superior, depends on the task. We obtain a more nuanced understanding of the results by analyzing them in terms of a time-cost model for the different components of navigation: way-finding, travel, number of travel steps, and context switching.},
	author = {Yang, Yalong and Cordeil, Maxime and Beyer, Johanna and Dwyer, Tim and Marriott, Kim and Pfister, Hanspeter},
	month = aug,
	year = {2020}
}

@article{drogemuller_examining_2020,
	title = {Examining virtual reality navigation techniques for {3D} network visualisations},
	volume = {56},
	issn = {2590-1184},
	url = {http://www.sciencedirect.com/science/article/pii/S2590118419300620},
	doi = {10.1016/j.cola.2019.100937},
	abstract = {Research into how virtual reality (VR) can be a beneficial technology for new and emerging large, complex data visualisations for data scientists is ongoing. In this paper, we evaluate three-dimensional VR navigation technique for data visualisations and test their effectiveness with a large graph visualisation. We evaluate two prominent navigation techniques employed in VR (Teleportation and One-Handed Flying) against two less common methods (Two-Handed Flying and Worlds-In-Miniature) and evaluate their performance and effectiveness through a series of tasks. We found Steering Patterns (One-Handed Flying and Two-Handed Flying) to be faster and preferred by participants for completing searching tasks in comparison to Teleportation. Worlds-In-Miniature was the least physically demanding of the navigations, and was preferred by participants for tasks that required an overview of the graph such as triangle counting.},
	language = {en},
	urldate = {2020-12-14},
	journal = {Journal of Computer Languages},
	author = {Drogemuller, Adam and Cunningham, Andrew and Walsh, James and Thomas, Bruce H. and Cordeil, Maxime and Ross, William},
	month = feb,
	year = {2020},
	keywords = {Navigation, Virtual reality, Graphs, Visualisation},
	pages = {100937}
}

@article{ghoniem_state_2019,
	title = {The {State} of the {Art} in {Multilayer} {Network} {Visualization}},
	url = {http://arxiv.org/abs/1902.06815},
	abstract = {Modelling relationships between entities in real-world systems with a simple graph is a standard approach. However, reality is better embraced as several interdependent subsystems (or layers). Recently the concept of a multilayer network model has emerged from the field of complex systems. This model can be applied to a wide range of real-world datasets. Examples of multilayer networks can be found in the domains of life sciences, sociology, digital humanities and more. Within the domain of graph visualization there are many systems which visualize datasets having many characteristics of multilayer graphs. This report provides a state of the art and a structured analysis of contemporary multilayer network visualization, not only for researchers in visualization, but also for those who aim to visualize multilayer networks in the domain of complex systems, as well as those developing systems across application domains. We have explored the visualization literature to survey visualization techniques suitable for multilayer graph visualization, as well as tools, tasks, and analytic techniques from within application domains. This report also identifies the outstanding challenges for multilayer graph visualization and suggests future research directions for addressing them.},
	urldate = {2020-08-28},
	journal = {arXiv:1902.06815 [cs]},
	author = {Ghoniem, Mohammad and Mcgee, Fintan and Melançon, Guy and Otjacques, Benoit and Pinaud, Bruno},
	month = feb,
	year = {2019},
	note = {arXiv: 1902.06815},
	keywords = {Computer Science - Social and Information Networks}
}

@misc{ribecca_circle_nodate,
	title = {Circle {Packing} - {The} {Data} {Visualisation} {Catalogue}},
	url = {https://datavizcatalogue.com/methods/circle_packing.html},
	urldate = {2020-12-19},
	month = dec,
	year = {2020},
	author = {Ribecca, Severino}
}


@inproceedings{sadana_redefining_2016,
	address = {New York, NY, USA},
	series = {{ISS} '16 {Companion}},
	title = {Redefining a {Contribution} for {Immersive} {Visualization} {Research}},
	isbn = {978-1-4503-4530-9},
	url = {https://doi.org/10.1145/3009939.3009946},
	doi = {10.1145/3009939.3009946},
	abstract = {Immersive computing modalities such as AR, VR, and speech-based input are regaining prominence as research threads in the visualization field due to the advancement in technology and availability of cheap consumer hardware. This renewed interest is similar to what we observed a decade ago when multitouch technology was gaining mainstream adoption. In this work, we reflect on lessons learned from designing for multitouch, with the goal of highlighting problems that may also emerge in AR/VR research. Specifically, we emphasize the need for the field to rearticulate what is expected from research efforts in the area of visualization on immersive technologies.},
	urldate = {2020-12-14},
	booktitle = {Proceedings of the 2016 {ACM} {Companion} on {Interactive} {Surfaces} and {Spaces}},
	publisher = {Association for Computing Machinery},
	author = {Sadana, Ramik and Setlur, Vidya and Stasko, John},
	month = nov,
	year = {2016},
	keywords = {ar, immersive technology, multitouch, speech, vr},
	pages = {41--45}
}

@book{diestel_graph_2017,
	address = {Berlin Heidelberg},
	edition = {5},
	series = {Graduate {Texts} in {Mathematics}},
	title = {Graph {Theory}},
	isbn = {978-3-662-53621-6},
	url = {https://www.springer.com/de/book/9783662536216},
	abstract = {This standard textbook of modern graph theory, now in its fifth edition, combines the authority of a classic with the engaging freshness of style that is the hallmark of active mathematics. It covers the core material of the subject with concise yet reliably complete proofs, while offering glimpses of more advanced methods in each field by one or two deeper results, again with proofs given in full detail. The book can be used as a reliable text for an introductory course, as a graduate text, and for self-study. From the reviews: “This outstanding book cannot be substituted with any other book on the present textbook market. It has every chance of becoming the standard textbook for graph theory.” Acta Scientiarum Mathematiciarum “Deep, clear, wonderful. This is a serious book about the heart of graph theory. It has depth and integrity.” Persi Diaconis \& Ron Graham, SIAM Review “The book has received a very enthusiastic reception, which it amply deserves. A masterly elucidation of modern graph theory.” Bulletin of the Institute of Combinatorics and its Applications “Succeeds dramatically ... a hell of a good book.” MAA Reviews “A highlight of the book is what is by far the best account in print of the Seymour-Robertson theory of graph minors.” Mathematika “ ... like listening to someone explain mathematics.” Bulletin of the AMS},
	language = {en},
	urldate = {2021-01-02},
	publisher = {Springer-Verlag},
	author = {Diestel, Reinhard},
	year = {2017},
	doi = {10.1007/978-3-662-53622-3},
}

@incollection{kerren_introduction_2014,
	address = {Cham},
	series = {Lecture {Notes} in {Computer} {Science}},
	title = {Introduction to {Multivariate} {Network} {Visualization}},
	isbn = {978-3-319-06793-3},
	url = {https://doi.org/10.1007/978-3-319-06793-3_1},
	abstract = {Information visualization focuses on the use of techniques to help people understand and analyze data. This chapter puts multivariate networks in the context of the aims of information visualization research, providing both formal and informal definitions of such networks. In addition, existing techniques for visualizing multivariate networks are described and classified.},
	language = {en},
	urldate = {2020-12-13},
	booktitle = {Multivariate {Network} {Visualization}: {Dagstuhl} {Seminar} \#13201, {Dagstuhl} {Castle}, {Germany}, {May} 12-17, 2013, {Revised} {Discussions}},
	publisher = {Springer International Publishing},
	author = {Kerren, Andreas and Purchase, Helen C. and Ward, Matthew O.},
	editor = {Kerren, Andreas and Purchase, Helen C. and Ward, Matthew O.},
	year = {2014},
	doi = {10.1007/978-3-319-06793-3_1},
	keywords = {Information Visualization, Abstract Data Type, Graph Topology, Interaction Technique, Visual Metaphor},
	pages = {1--9}
}

@inproceedings{eades_multilevel_1997,
	address = {Berlin, Heidelberg},
	series = {Lecture {Notes} in {Computer} {Science}},
	title = {Multilevel visualization of clustered graphs},
	isbn = {978-3-540-68048-2},
	doi = {10.1007/3-540-62495-3_41},
	abstract = {Clustered graphs are graphs with recursive clustering structures over the vertices. This type of structure appears in many systems. Examples include CASE tools, management information systems, VLSI design tools, and reverse engineering systems. Existing layout algorithms represent the clustering structure as recursively nested regions in the plane. However, as the structure becomes more and more complex, two dimensional plane representations tend to be insufficient. In this paper, firstly, we describe some two dimensional plane drawing algorithms for clustered graphs; then we show how to extend two dimensional plane drawings to three dimensional multilevel drawings. We consider two conventions: straight-line convex drawings and orthogonal rectangular drawings; and we show some examples.},
	language = {en},
	booktitle = {Graph {Drawing}},
	publisher = {Springer},
	author = {Eades, Peter and Feng, Qing-Wen},
	editor = {North, Stephen},
	year = {1997},
	keywords = {Edge Crossing, Hierarchical Graph, Inclusion Tree, Outer Face, Plane Drawing},
	pages = {101--112}
}

@inproceedings{bertault_algorithm_1999,
	address = {Berlin, Heidelberg},
	series = {Lecture {Notes} in {Computer} {Science}},
	title = {An {Algorithm} for {Drawing} {Compound} {Graphs}},
	isbn = {978-3-540-46648-2},
	doi = {10.1007/3-540-46648-7_20},
	abstract = {We present a new algorithm, called Nuage, for drawing graphs with both adjacency and inclusion relationships between nodes, that is, compound graphs. Compound graphs are more general than classical graph models or clustered graphs. Nuage can be applied to both directed and undirected compound graphs. It can be parameterized by classical graph drawing algorithms. Nuage can be viewed as a method for unifying several classical algorithms within the same drawing by using the structure of the compound graph. Additionally, we present a refinement technique that can be used in conjunction with Nuage to reduce the number of edge crossings.},
	language = {en},
	booktitle = {Graph {Drawing}},
	publisher = {Springer},
	author = {Bertault, François and Miller, Mirka},
	editor = {Kratochvíyl, Jan},
	year = {1999},
	pages = {197--204}
}

@inproceedings{kobourov_gestalt_2015,
	address = {Cham},
	series = {Lecture {Notes} in {Computer} {Science}},
	title = {Gestalt {Principles} in {Graph} {Drawing}},
	isbn = {978-3-319-27261-0},
	doi = {10.1007/978-3-319-27261-0_50},
	abstract = {Gestalt principles are rules for the organization of perceptual scenes. They were introduced in the context of philosophy and psychology in the 19th century and were used to define principles of human perception in the early 20th century. The Gestalt (form, in German) principles include, among others: proximity, the grouping of closely positioned objects; similarity, the grouping of objects of similar shape or color; continuation, the grouping of objects that form a continuous pattern; and symmetry, the grouping of objects that form symmetric patterns. Gestalt principles have been extensively applied in user interface design, graphic design, and information visualization.},
	language = {en},
	booktitle = {Graph {Drawing} and {Network} {Visualization}},
	publisher = {Springer International Publishing},
	author = {Kobourov, Stephen G. and Mchedlidze, Tamara and Vonessen, Laura},
	editor = {Di Giacomo, Emilio and Lubiw, Anna},
	year = {2015},
	keywords = {Gestalt Principles, Graph Drawing Conventions, Node-link Diagrams, Proximity Drawings, Scene Perception},
	pages = {558--560}
}


@article{von_landesberger_visual_2011,
	title = {Visual {Analysis} of {Large} {Graphs}: {State}-of-the-{Art} and {Future} {Research} {Challenges}},
	volume = {30},
	issn = {01677055},
	shorttitle = {Visual {Analysis} of {Large} {Graphs}},
	url = {http://doi.wiley.com/10.1111/j.1467-8659.2011.01898.x},
	doi = {10.1111/j.1467-8659.2011.01898.x},
	abstract = {The analysis of large graphs plays a prominent role in various fields of research and is relevant in many important application areas. Effective visual analysis of graphs requires appropriate visual presentations in combination with respective user interaction facilities and algorithmic graph analysis methods. How to design appropriate graph analysis systems depends on many factors, including the type of graph describing the data, the analytical task at hand, and the applicability of graph analysis methods. The most recent surveys of graph visualization and navigation techniques cover techniques that had been introduced until 2000 or concentrate only on graph layouts published until 2002. Recently, new techniques have been developed covering a broader range of graph types, such as time-varying graphs. Also, in accordance with ever growing amounts of graph-structured data becoming available, the inclusion of algorithmic graph analysis and interaction techniques becomes increasingly important. In this State-of-the-Art Report, we survey available techniques for the visual analysis of large graphs. Our review firstly considers graph visualization techniques according to the type of graphs supported. The visualization techniques form the basis for the presentation of interaction approaches suitable for visual graph exploration. As an important component of visual graph analysis, we discuss various graph algorithmic aspects useful for the different stages of the visual graph analysis process. We also present main open research challenges in this field.},
	language = {en},
	number = {6},
	urldate = {2021-01-03},
	journal = {Computer Graphics Forum},
	author = {von Landesberger, T. and Kuijper, A. and Schreck, T. and Kohlhammer, J. and van Wijk, J.J. and Fekete, J.-D. and Fellner, D.W.},
	month = sep,
	year = {2011},
	pages = {1719--1749}
}

@article{kobourov_spring_2012,
	title = {Spring {Embedders} and {Force} {Directed} {Graph} {Drawing} {Algorithms}},
	url = {http://arxiv.org/abs/1201.3011},
	abstract = {Force-directed algorithms are among the most flexible methods for calculating layouts of simple undirected graphs. Also known as spring embedders, such algorithms calculate the layout of a graph using only information contained within the structure of the graph itself, rather than relying on domain-specific knowledge. Graphs drawn with these algorithms tend to be aesthetically pleasing, exhibit symmetries, and tend to produce crossing-free layouts for planar graphs. In this survey we consider several classical algorithms, starting from Tutte's 1963 barycentric method, and including recent scalable multiscale methods for large and dynamic graphs.},
	urldate = {2020-09-08},
	journal = {arXiv:1201.3011 [cs]},
	author = {Kobourov, Stephen G.},
	month = jan,
	year = {2012},
	keywords = {Computer Science - Computational Geometry, Computer Science - Data Structures and Algorithms, Computer Science - Discrete Mathematics, F.2.2, G.2.2, H.4.0, I.3.5}
}

@article{kamada_algorithm_1989,
	title = {{AN} {ALGORITHM} {FOR} {DRAWING} {GENERAL} {UNDIRECTED} {GRAPHS}},
	volume = {31},
	language = {en},
	number = {1},
	journal = {INFORMATION PROCESSING LETTERS},
	author = {Kamada, Tomihisa and Kawai, Satoru},
	year = {1989},
	pages = {9}
}

@article{fruchterman_graph_1991,
	title = {Graph drawing by force-directed placement},
	volume = {21},
	copyright = {Copyright © 1991 John Wiley \& Sons, Ltd},
	issn = {1097-024X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/spe.4380211102},
	doi = {https://doi.org/10.1002/spe.4380211102},
	abstract = {We present a modification of the spring-embedder model of Eades [Congressus Numerantium, 42, 149–160, (1984)] for drawing undirected graphs with straight edges. Our heuristic strives for uniform edge lengths, and we develop it in analogy to forces in natural systems, for a simple, elegant, conceptually-intuitive, and efficient algorithm.},
	language = {en},
	number = {11},
	urldate = {2020-12-13},
	journal = {Software: Practice and Experience},
	author = {Fruchterman, Thomas M. J. and Reingold, Edward M.},
	year = {1991},
	keywords = {Force-directed placement, Graph drawing, Multi-level techniques, Simulated annealing},
	pages = {1129--1164}
}

@INPROCEEDINGS{Sutherland65theultimate,
    author = {Ivan E. Sutherland},
    title = {The Ultimate Display},
    booktitle = {Proceedings of the IFIP Congress},
    year = {1965},
    pages = {506--508}
}

@article{cruz-neira_cave_1992,
	title = {The {CAVE}: audio visual experience automatic virtual environment},
	volume = {35},
	issn = {0001-0782, 1557-7317},
	shorttitle = {The {CAVE}},
	url = {https://dl.acm.org/doi/10.1145/129888.129892},
	doi = {10.1145/129888.129892},
	language = {en},
	number = {6},
	urldate = {2020-12-14},
	journal = {Communications of the ACM},
	author = {Cruz-Neira, Carolina and Sandin, Daniel J. and DeFanti, Thomas A. and Kenyon, Robert V. and Hart, John C.},
	month = jun,
	year = {1992},
	pages = {64--72}
}

@misc{khronosGroupOpenXR,
  author       = {Khronos Group},
  title        = {OpenXR Specification - official Website},
  howpublished = {https://www.khronos.org/openxr/},
  year         = {2021}, 
  month        = feb,
}

@misc{OpenVRValve,
  author       = {Valve Corporation},
  title        = {OpenVR Source Code Github Repo},
  howpublished = {https://github.com/ValveSoftware/openvr},
  year         = {2021}, 
  month        = feb,
}

@misc{webxr,
  author = {Immersive Web Working Group},
  title        = {WebXR Specification},
  howpublished = {https://immersiveweb.dev/},
  year         = {2021}, 
  month = feb,	
}

@misc{webvr,
  author = {WebVR Working Group},
  title        = {WebVR Specification},
  howpublished = {https://webvr.info/},
  year         = {2021}, 
  month = feb,	
}

@article{schulz_treevisnet_2011,
	title = {Treevis.net: {A} {Tree} {Visualization} {Reference}},
	volume = {31},
	issn = {1558-1756},
	shorttitle = {Treevis.net},
	doi = {10.1109/MCG.2011.103},
	abstract = {Tree visualization is one of the best-studied areas of information visualization; researchers have developed more than 200 visualization and layout techniques for trees. The treevis.net project aims to provide a hand-curated bibliographical reference to this ever-growing wealth of techniques. It offers a visual overview that users can filter to a desired subset along the design criteria of dimensionality, edge representation, and node alignment. Details, including links to the original publications, can be brought up on demand. Treevis.net has become a community effort, with researchers sending in preprints of their tree visualization techniques to be published or pointing out additional information.},
	number = {6},
	journal = {IEEE Computer Graphics and Applications},
	author = {Schulz, H.},
	month = nov,
	year = {2011},
	keywords = {data visualisation, Visualization, Tree data structures, tree visualization, Information analysis, information visualization, Image edge detection, Computer Graphics, Information Storage and Retrieval, computer graphics, dimensionality, edge detection, edge representation, graphics and multimedia, handcurated bibliographical reference, Image representation, Internet, node alignment, tree visualization reference, treevis.net, Treevis.net},
	pages = {11--15}
}

@inproceedings{song_lenstree_2006,
	title = {{LensTree}: {Browsing} and {Navigating} {Large} {Hierarchical} {Information} {Structures}},
	isbn = {0-7695-2754-X},
	doi = {10.1109/ICAT.2006.81},
	abstract = {This paper presents LensTree, a novel browsing and navigation tool for large hierarchical information structures. It enhances traditional indented lists by applying focus+context view to its design. LensTree dynamically changes the sizes of nodes to provide a focal area around the mouse pointer while keeping nodes in the peripheral area in smaller sizes as context. This enables it to display a larger hierarchy than traditional indented lists within the same screen area. Therefore scrolling and expanding/collapsing are less often used so that it is more efficient for performing browsing and navigation tasks. An informal user test was conducted and the users showed strong interest to LensTree's visual presentation. It suggested that this technique was worth further exploitation.},
	booktitle = {{ICAT}'06: {Proceedings} of the {International} {Conference} on {Artificial} {Reality} and {Telexistence}},
	publisher = {IEEE Computer Society},
	author = {Song, Hongzhi and Qi, Yu and Xiao, Lei and Zhu, Tonglin and Curran, Edwin P.},
	editor = {Chen, Qingzhang and Liang, Ronghua and Pan, Zhigeng},
	year = {2006},
	pages = {682--687}
}

@inproceedings{arce-orozco_radial_2017,
	title = {Radial {Tree} in {Bunches}: {Optimizing} the use of space in the visualization of radial trees},
	isbn = {978-1-5386-2645-0},
	doi = {10.1109/INCISCOS.2017.32},
	abstract = {The graphical representation of information hierarchies makes it easy to recognize the relationships between the different elements of such structures. The radial tree is a technique for drawing hierarchies that is visually attractive, intuitive and uses space in an efficient way. Although the technique was developed in the late 1970s, it has recently acquired more interest due to its use in several modern information visualization systems. In this paper, we present a brief review of the basic algorithms to drawing radial trees and propose a new algorithm that allow to make a more efficient use of the available space.},
	booktitle = {{INCISCOS}'17: {Proceedings} of the {International} {Conference} on {Information} {Systems} and {Computer} {Science}},
	publisher = {IEEE Computer Society},
	author = {Arce-Orozco, Armando and Camacho-Valerio, Luis and Madrigal-Quesada, Steven},
	editor = {Mora, Sergio Lujan},
	year = {2017},
	pages = {369--374}
}

@inproceedings{munzner_h3_1997,
	title = {H3: laying out large directed graphs in {3D} hyperbolic space},
	shorttitle = {H3},
	doi = {10.1109/INFVIS.1997.636718},
	abstract = {We present the H3 layout technique for drawing large directed graphs as node-link diagrams in 3D hyperbolic space. We can lay out much larger structures than can be handled using traditional techniques for drawing general graphs because we assume a hierarchical nature of the data. We impose a hierarchy on the graph by using domain-specific knowledge to find an appropriate spanning tree. Links which are not part of the spanning tree do not influence the layout but can be selectively drawn by user request. The volume of hyperbolic 3-space increases exponentially, as opposed to the familiar geometric increase of euclidean 3-space. We exploit this exponential amount of room by computing the layout according to the hyperbolic metric. We optimize the cone tree layout algorithm for 3D hyperbolic space by placing children on a hemisphere around the cone mouth instead of on its perimeter. Hyperbolic navigation affords a Focus+Context view of the structure with minimal visual clutter. We have successfully laid out hierarchies of over 20,000 nodes. Our implementation accommodates navigation through graphs too large to be rendered interactively by allowing the user to explicitly prune or expand subtrees.},
	booktitle = {Proceedings of {VIZ} '97: {Visualization} {Conference}, {Information} {Visualization} {Symposium} and {Parallel} {Rendering} {Symposium}},
	author = {Munzner, T.},
	month = oct,
	year = {1997},
	keywords = {3D hyperbolic space, Computer science, cone tree layout algorithm, data visualisation, data visualization, diagrams, directed graphs, domain-specific knowledge, euclidean 3-space, File systems, graph drawing, H3 layout technique, hierarchical data, History, hyperbolic navigation, Information systems, large directed graphs, Mouth, Navigation, node-link diagrams, optimisation, optimization, spanning tree, subtree pruning, Tree graphs, trees (mathematics), visual clutter, Visualization, Web page design, Web sites},
	pages = {2--10}
}

@inproceedings{robertson_cone_1991,
	title = {Cone {Trees}: {Animated} {3D} visualizations of hierarchical information},
	isbn = {0-89791-383-3},
	doi = {10.1145/108844.108883},
	abstract = {The task of managing and accessing large information spaces is a problem in large scale cognition. Emerging technologies for 3D visualization and interactive animation offer potential solutions to this problem, especially when the structure of the information can be visualized. We describe one of these Information Visualization techniques, called the Cone Tree, which is used for visualizing hierarchical information structures. The hierarchy is presented in 3D to maximize effective use of available screen space and enable visualization of the whole structure. Interactive animation is used to shift some of the user's cognitive load to the human perceptual system.},
	booktitle = {{CHI}'91: {Proceedings} of the {SIGCHI} {Conference} on {Human} {Factors} in {Computing} {Systems}},
	publisher = {ACM Press},
	author = {Robertson, George G. and Mackinlay, Jock D. and Card, Stuart K.},
	editor = {Robertson, Scott P. and Olson, Gary M. and Olson, Judith S.},
	year = {1991},
	pages = {189--194}
}

@article{shneiderman_tree_1992,
	title = {Tree visualization with tree-maps: 2-d space-filling approach},
	volume = {11},
	issn = {0730-0301},
	shorttitle = {Tree visualization with tree-maps},
	url = {https://doi.org/10.1145/102377.115768},
	doi = {10.1145/102377.115768},
	number = {1},
	urldate = {2020-12-11},
	journal = {ACM Transactions on Graphics},
	author = {Shneiderman, Ben},
	month = jan,
	year = {1992},
	pages = {92--99}
}

@article{gortler_bubble_2018,
	title = {Bubble {Treemaps} for {Uncertainty} {Visualization}},
	volume = {24},
	issn = {1941-0506},
	doi = {10.1109/TVCG.2017.2743959},
	abstract = {We present a novel type of circular treemap, where we intentionally allocate extra space for additional visual variables. With this extended visual design space, we encode hierarchically structured data along with their uncertainties in a combined diagram. We introduce a hierarchical and force-based circle-packing algorithm to compute Bubble Treemaps, where each node is visualized using nested contour arcs. Bubble Treemaps do not require any color or shading, which offers additional design choices. We explore uncertainty visualization as an application of our treemaps using standard error and Monte Carlo-based statistical models. To this end, we discuss how uncertainty propagates within hierarchies. Furthermore, we show the effectiveness of our visualization using three different examples: the package structure of Flare, the S\&P 500 index, and the US consumer expenditure survey.},
	number = {1},
	journal = {IEEE Transactions on Visualization and Computer Graphics},
	author = {Görtler, J. and Schulz, C. and Weiskopf, D. and Deussen, O.},
	month = jan,
	year = {2018},
	keywords = {Data visualization, data visualisation, Visualization, tree data structures, Layout, Standards, circle packing, bubble treemaps, circle-packing algorithm, circular treemap, Computational modeling, contours, extended visual design space, Flare, hierarchically structured data, hierarchy visualization, Indexes, Monte Carlo methods, Monte Carlo-based statistical model, nested contour arcs, S\&P 500 index, standard error, statistical analysis, tree layout, treemaps, Uncertainty, uncertainty visualization, Uncertainty visualization, US consumer expenditure survey, visual variables},
	pages = {719--728}
}

@inproceedings{wang_visualization_2006,
	address = {New York, NY, USA},
	series = {{CHI} '06},
	title = {Visualization of large hierarchical data by circle packing},
	isbn = {978-1-59593-372-0},
	url = {https://doi.org/10.1145/1124772.1124851},
	doi = {10.1145/1124772.1124851},
	abstract = {In this paper a novel approach is described for tree visualization using nested circles. The brother nodes at the same level are represented by externally tangent circles; the tree nodes at different levels are displayed by using 2D nested circles or 3D nested cylinders. A new layout algorithm for tree structure is described. It provides a good overview for large data sets. It is easy to see all the branches and leaves of the tree. The new method has been applied to the visualization of file systems.},
	urldate = {2020-12-10},
	booktitle = {Proceedings of the {SIGCHI} {Conference} on {Human} {Factors} in {Computing} {Systems}},
	publisher = {Association for Computing Machinery},
	author = {Wang, Weixin and Wang, Hui and Dai, Guozhong and Wang, Hongan},
	month = apr,
	year = {2006},
	keywords = {tree visualization, circle packing, file system, nested circles},
	pages = {517--520}
}

@inproceedings{balzer_hierarchy_2004,
	title = {Hierarchy {Based} {3D} {Visualization} of {Large} {Software} {Structures}},
	doi = {10.1109/VISUAL.2004.39},
	abstract = {Modern object-oriented programs are hierarchical systems with many thousands of interrelated subsystems. Visualization helps developers to better comprehend these large and complex systems. This work presents a three-dimensional visualization technique that represents the static structure of object-oriented software using distributions of three-dimensional objects on a two-dimensional plane. The visual complexity is reduced by adjusting the transparency of object surfaces to the distance of the viewpoint. An approach called Hierarchical Net is proposed for a clear representation of the relationships between the subsystems.},
	booktitle = {{IEEE} {Visualization} 2004},
	author = {Balzer, M. and Deussen, O.},
	month = oct,
	year = {2004},
	keywords = {Application software, Data mining, Data visualization, Hierarchical systems, Java, Object oriented modeling, Packaging, Software maintenance, Software packages, Software systems},
	pages = {4p--4p}
}

@article{itoh_hierarchical_2004,
	title = {Hierarchical data visualization using a fast rectangle-packing algorithm},
	volume = {10},
	issn = {1941-0506},
	doi = {10.1109/TVCG.2004.1272729},
	abstract = {We present a technique for the representation of large-scale hierarchical data which aims to provide good overviews of complete structures and the content of the data in one display space. The technique represents the data by using nested rectangles. It first packs icons or thumbnails of the lowest-level data and then generates rectangular borders that enclose the packed data. It repeats the process of generating rectangles that enclose the lower-level rectangles until the highest-level rectangles are packed. We present two rectangle-packing algorithms for placing items of hierarchical data onto display spaces. The algorithms refer to Delaunay triangular meshes connecting the centers of rectangles to find gaps where rectangles can be placed. The first algorithm places rectangles where they do not overlap each other and where the extension of the layout area is minimal. The second algorithm places rectangles by referring to templates describing the ideal positions for nodes of input data. It places rectangles where they do not overlap each other and where the combination of the layout area and the distances between the positions described in the template and the actual positions is minimal. It can smoothly represent time-varying data by referring to templates that describe previous layout results. It is also suitable for semantics-based or design-based data layout by generating templates according to the semantics or design.},
	number = {3},
	journal = {IEEE Transactions on Visualization and Computer Graphics},
	author = {Itoh, T. and Yamaguchi, Y. and Ikehata, Y. and Kajinaga, Y.},
	month = may,
	year = {2004},
	keywords = {Data visualization, data visualisation, Navigation, Algorithms, Computer Society, data structures, computational complexity, computational geometry, Computer displays, Computer Graphics, Database Management Systems, Databases, Factual, Delaunay triangular meshes, design-based data layout, display spaces, Frequency, hierarchical data visualization, Image Enhancement, Image Interpretation, Computer-Assisted, Information Storage and Retrieval, Joining processes, Large-scale systems, mesh generation, Monitoring, nested rectangles, rectangle-packing algorithms, rectangular border generation, semantics-based data layout, time-varying data, User interfaces, User-Computer Interface, Web pages},
	pages = {302--313}
}

@article{ducruet_multilayer_nodate,
	title = {Multilayer dynamics of complex spatial networks: {The} case of global maritime flows (1977–2008)},
	volume = {60},
	issn = {0966-6923},
	shorttitle = {Multilayer dynamics of complex spatial networks},
	url = {https://www.sciencedirect.com/science/article/pii/S0966692316305944},
	doi = {10.1016/j.jtrangeo.2017.02.007},
	abstract = {This article investigates the degree of overlap among the different layers of circulation composing global maritime flows in recent decades. Mobilizing several methods originating from complex networks allows us to shed new light on specialization and diversification dynamics affecting the evolution of ports and shipping. The principal confirm the strong and path-dependent influence of multiplexity on traffic volume, range of interaction and centrality from various perspectives, such as matrices correlations, homophily, assortativity, and single linkage analysis. While the network grows and concentrates around large hubs over time, traffic distribution is also place-dependent due to the reinforced position of already established nodes.},
	language = {en},
	urldate = {2021-03-10},
	journal = {Journal of Transport Geography},
	author = {Ducruet, César},
	month = apr,
	year = {2017},
	keywords = {Assortativity, Homophily, Maritime transport, Path-dependency, Port, Spatial network},
	pages = {47--58},
}


@article{de_domenico_muxviz_2015,
	title = {{MuxViz}: a tool for multilayer analysis and visualization of networks},
	volume = {3},
	issn = {2051-1310},
	shorttitle = {{MuxViz}},
	url = {https://doi.org/10.1093/comnet/cnu038},
	doi = {10.1093/comnet/cnu038},
	abstract = {Multilayer relationships among entities and information about entities must be accompanied by the means to analyse, visualize and obtain insights from such data. We present open-source software (muxViz) that contains a collection of algorithms for the analysis of multilayer networks, which are an important way to represent a large variety of complex systems throughout science and engineering. We demonstrate the ability of muxViz to analyse and interactively visualize multilayer data using empirical genetic, neuronal and transportation networks. Our software is available at https://github.com/manlius/muxViz.},
	number = {2},
	urldate = {2021-01-20},
	journal = {Journal of Complex Networks},
	author = {De Domenico, Manlio and Porter, Mason A. and Arenas, Alex},
	month = jun,
	year = {2015},
	pages = {159--176}
}

@inproceedings{balzer_level--detail_2007,
	title = {Level-of-detail visualization of clustered graph layouts},
	doi = {10.1109/APVIS.2007.329288},
	abstract = {The level-of-detail techniques presented in this paper enable a comprehensible interactive visualization of large and complex clustered graph layouts either in 2D or 3D. Implicit surfaces are used for the visually simplified representation of vertex clusters, and so-called edge bundles are formed for the simplification of edges. Additionally, dedicated transition techniques are provided for continuously adaptive and adjustable views of graphs that range from very abstract to very detailed representations.},
	booktitle = {2007 6th {International} {Asia}-{Pacific} {Symposium} on {Visualization}},
	author = {Balzer, M. and Deussen, O.},
	month = feb,
	year = {2007},
	keywords = {clustered graph layout, Computer graphics, Data mining, data visualisation, Data visualization, Ellipsoids, graph theory, Information science, interactive systems, interactive visualization, Layout, level-of-detail visualization, pattern clustering, Rendering (computer graphics), Routing, Shape, User interfaces},
	pages = {133--140}
}

@article{jonker_graph_2017,
	title = {Graph mapping: {Multi}-scale community visualization of massive graph data},
	volume = {16},
	issn = {1473-8716},
	shorttitle = {Graph mapping},
	url = {https://doi.org/10.1177/1473871616661195},
	doi = {10.1177/1473871616661195},
	abstract = {Graph visualizations increase the perception of entity relationships in a network. However, as graph size and density increases, readability rapidly diminishes. In this article, we present an end-to-end, tile-based visual analytic approach called graph mapping that utilizes cluster computing to turn large-scale graph (node?link) data into interactive visualizations in modern web browsers. Our approach is designed for end-user analysis of community structure and relationships at macro- and micro scales. We also present the results of several experiments using alternate methods for qualitatively improving comprehensibility of hierarchical community detection visualizations by proposing constraints to state-of-the-art modularity maximization algorithms.},
	number = {3},
	urldate = {2021-01-21},
	journal = {Information Visualization},
	author = {Jonker, David and Langevin, Scott and Giesbrecht, David and Crouch, Michael and Kronenfeld, Nathan},
	month = jul,
	year = {2017},
	note = {Publisher: SAGE Publications},
	pages = {190--204}
}

@article{sorger_immersive_2019,
	 title =  {Immersive Analytics of Large Dynamic Networks via Overview
               and Detail Navigation},
  author =     {Johannes Sorger and Manuela Waldner and Wolfgang Knecht and
               Alessio Arleo},
  year =  {2019},
  abstract =   {Analysis of large dynamic networks is a thriving research
               field, typically relying on 2D graph representations. The
               advent of affordable head mounted displays sparked new
               interest in the potential of 3D visualization for immersive
               network analytics. Nevertheless, most solutions do not scale
               well with the number of nodes and edges and rely on
               conventional fly- or walk-through navigation. In this paper,
               we present a novel approach for the exploration of large
               dynamic graphs in virtual reality that interweaves two
               navigation metaphors: overview exploration and immersive
               detail analysis. We thereby use the potential of
               state-of-the-art VR headsets, coupled with a web-based 3D
               rendering engine that supports heterogeneous input
               modalities to enable ad-hoc immersive network analytics. We
               validate our approach through a performance evaluation and a
               case study with experts analyzing medical data.},
  month =      dec,
  booktitle =  {2nd International Conference on Artificial Intelligence &
               Virtual Reality},
  event =      {AIVR 2019},
  location =   {San Diego, California, USA},
  organization = {IEEE},
  pages =      {144--151},
  keywords =   {Immersive Network Analytics, Web-Based Visualization,
               Dynamic Graph Visualization},
  URL =        {https://www.cg.tuwien.ac.at/research/publications/2019/sorger-2019-odn/},
}

@article{maaten_visualizing_2008,
	title = {Visualizing {Data} using t-{SNE}},
	volume = {9},
	url = {http://jmlr.org/papers/v9/vandermaaten08a.html},
	number = {86},
	journal = {Journal of Machine Learning Research},
	author = {Maaten, Laurens van der and Hinton, Geoffrey},
	year = {2008},
	pages = {2579--2605}
}
@article{kwon_study_2016,
	title = {A {Study} of {Layout}, {Rendering}, and {Interaction} {Methods} for {Immersive} {Graph} {Visualization}},
	volume = {22},
	issn = {1941-0506},
	doi = {10.1109/TVCG.2016.2520921},
	abstract = {Information visualization has traditionally limited itself to 2D representations, primarily due to the prevalence of 2D displays and report formats. However, there has been a recent surge in popularity of consumer grade 3D displays and immersive head-mounted displays (HMDs). The ubiquity of such displays enables the possibility of immersive, stereoscopic visualization environments. While techniques that utilize such immersive environments have been explored extensively for spatial and scientific visualizations, contrastingly very little has been explored for information visualization. In this paper, we present our considerations of layout, rendering, and interaction methods for visualizing graphs in an immersive environment. We conducted a user study to evaluate our techniques compared to traditional 2D graph visualization. The results show that participants answered significantly faster with a fewer number of interactions using our techniques, especially for more difficult tasks. While the overall correctness rates are not significantly different, we found that participants gave significantly more correct answers using our techniques for larger graphs.},
	number = {7},
	journal = {IEEE Transactions on Visualization and Computer Graphics},
	author = {Kwon, Oh-Hyun and Muelder, Chris and Lee, Kyungwon and Ma, Kwan-Liu},
	month = jul,
	year = {2016},
	keywords = {rendering (computer graphics), Rendering (computer graphics), virtual reality, Data visualization, data visualisation, Graph visualization, information visualization, 2D graph visualization, consumer grade 3D displays, head-mounted display, HMD, Image edge detection, immersive environments, immersive graph visualization, immersive head-mounted displays, interaction method, Layout, layout method, rendering method, Stereo image processing, stereoscopic visualization environment, Three-dimensional displays, Two dimensional displays},
	pages = {1802--1815}
}

@inproceedings{halpin_exploring_2008,
	address = {Berlin, Heidelberg},
	title = {Exploring {Semantic} {Social} {Networks} {Using} {Virtual} {Reality}},
	isbn = {978-3-540-88564-1},
	abstract = {We present Redgraph, the first generic virtual reality visualization program for Semantic Web data. Redgraph is capable of handling large data-sets, as we demonstrate on social network data from the U.S. Patent Trade Office. We develop a Semantic Web vocabulary of virtual reality terms compatible with GraphXML to map graph visualization into the Semantic Web itself. Our approach to visualizing Semantic Web data takes advantage of user-interaction in an immersive environment to bypass a number of difficult issues in 3-dimensional graph visualization layout by relying on users themselves to interactively extrude the nodes and links of a 2-dimensional graph into the third dimension. When users touch nodes in the virtual reality environment, they retrieve data formatted according to the data's schema or ontology. We applied Redgraph to social network data constructed from patents, inventors, and institutions from the United States Patent and Trademark Office in order to explore networks of innovation in computing. Using this data-set, results of a user study comparing extrusion (3-D) vs. no-extrusion (2-D) are presented. The study showed the use of a 3-D interface by subjects led to significant improvement on answering of fine-grained questions about the data-set, but no significant difference was found for broad questions about the overall structure of the data. Furthermore, inference can be used to improve the visualization, as demonstrated with a data-set of biotechnology patents and researchers.},
	booktitle = {The {Semantic} {Web} - {ISWC} 2008},
	publisher = {Springer Berlin Heidelberg},
	author = {Halpin, Harry and Zielinski, David J. and Brady, Rachael and Kelly, Glenda},
	editor = {Sheth, Amit and Staab, Steffen and Dean, Mike and Paolucci, Massimo and Maynard, Diana and Finin, Timothy and Thirunarayan, Krishnaprasad},
	year = {2008},
	pages = {599--614}
}

@inproceedings{usoh_walking_1999,
	title = {Walking {\textgreater} walking-in-place {\textgreater} flying, in virtual environments},
	isbn = {978-0-201-48560-8},
	url = {http://portal.acm.org/citation.cfm?doid=311535.311589},
	doi = {10.1145/311535.311589},
	abstract = {A study by Slater, et al., [1995] indicated that naive subjects in an immersive virtual environment experience a higher subjective sense of presence when they locomote by walking-in-place (virtual walking) than when they push-button-fly (along the floor plane). We replicated their study, adding real walking as a third condition.},
	language = {en},
	urldate = {2020-12-14},
	booktitle = {Proceedings of the 26th annual conference on {Computer} graphics and interactive techniques  - {SIGGRAPH} '99},
	publisher = {ACM Press},
	author = {Usoh, Martin and Arthur, Kevin and Whitton, Mary C. and Bastos, Rui and Steed, Anthony and Slater, Mel and Brooks, Frederick P.},
	year = {1999},
	pages = {359--364}
}

@inproceedings{zielasko_remain_2017,
	title = {Remain seated: towards fully-immersive desktop {VR}},
	shorttitle = {Remain seated},
	doi = {10.1109/WEVR.2017.7957707},
	abstract = {In this work we describe the scenario of fully-immersive desktop VR, which serves the overall goal to seamlessly integrate with existing workflows and workplaces of data analysts and researchers, such that they can benefit from the gain in productivity when immersed in their data-spaces. Furthermore, we provide a literature review showing the status quo of techniques and methods available for realizing this scenario under the raised restrictions. Finally, we propose a concept of an analysis framework and the decisions made and the decisions still to be taken, to outline how the described scenario and the collected methods are feasible in a real use case.},
	booktitle = {2017 {IEEE} 3rd {Workshop} on {Everyday} {Virtual} {Reality} ({WEVR})},
	author = {Zielasko, D. and Weyers, B. and Bellgardt, M. and Pick, S. and Meibner, A. and Vierjahn, T. and Kuhlen, T. W.},
	month = mar,
	year = {2017},
	keywords = {virtual reality, Visualization, data analysis, Data analysis, data analysts, data-spaces, Employment, fully-immersive desktop VR, Hardware, Keyboards, Mice, productivity, Productivity},
	pages = {1--6}
}

@inproceedings{nguyen-vo_simulated_2018,
	address = {Reutlingen},
	title = {Simulated {Reference} {Frame}: {A} {Cost}-{Effective} {Solution} to {Improve} {Spatial} {Orientation} in {VR}},
	isbn = {978-1-5386-3365-6},
	shorttitle = {Simulated {Reference} {Frame}},
	url = {https://ieeexplore.ieee.org/document/8446383/},
	doi = {10.1109/VR.2018.8446383},
	abstract = {Virtual Reality (VR) is increasingly used in spatial cognition research, as it offers high experimental control in naturalistic multimodal environments, which is hard to achieve in real-world settings. Although recent technological advances offer a high level of photorealism, locomotion in VR is still restricted because people might not perceive their self-motion as they would in the real world. This might be related to the inability to use embodied spatial orientation processes, which support automatic and obligatory updating of our spatial awareness. Previous research has identified the roles reference frames play in retaining spatial orientation. Here, we propose using visually overlaid rectangular boxes, simulating reference frames in VR, to provide users with a better insight into spatial direction in landmark-free virtual environments. The current mixedmethod study investigated how different variations of the visually simulated reference frames might support people in a navigational search task. Performance results showed that the existence of a simulated reference frame yields significant effects on participants completion time and travel distance. Though a simulated CAVE translating with the navigator (one of the simulated reference frames) did not provide significant benefits, the simulated room (another simulated reference frame depicting a rest frame) significantly boosted user performance in the task as well as improved participants preference in the post-experiment evaluation. Results suggest that adding a visually simulated reference frame to VR applications might be a cost-effective solution to the spatial disorientation problem in VR.},
	language = {en},
	urldate = {2020-12-15},
	booktitle = {2018 {IEEE} {Conference} on {Virtual} {Reality} and {3D} {User} {Interfaces} ({VR})},
	publisher = {IEEE},
	author = {Nguyen-Vo, Thinh and Riecke, Bernhard E. and Stuerzlinger, Wolfgang},
	month = mar,
	year = {2018},
	pages = {415--422}
}

@inproceedings{lee_evaluating_2020,
	address = {New York, NY, USA},
	series = {{VRST} '20},
	title = {Evaluating {Automatic} {Parameter} {Control} {Methods} for {Locomotion} in {Multiscale} {Virtual} {Environments}},
	isbn = {978-1-4503-7619-8},
	url = {https://doi.org/10.1145/3385956.3418961},
	doi = {10.1145/3385956.3418961},
	abstract = {Virtual environments with a wide range of scales are becoming commonplace in Virtual Reality applications. Methods to control locomotion parameters can help users explore such environments more easily. For multi-scale virtual environments, point-and-teleport locomotion with a well-designed distance control method can enable mid-air teleportation, which makes it competitive to flying interfaces. Yet, automatic distance control for point-and-teleport has not been studied in such environments. We present a new method to automatically control the distance for point-and-teleport. In our first user study, we used a solar system environment to compare three methods: automatic distance control for point-and-teleport, manual distance control for point-and-teleport, and automatic speed control for flying. Results showed that automatic control significantly reduces overshoot compared with manual control for point-and-teleport, but the discontinuous nature of teleportation made users prefer flying with automatic speed control. We conducted a second study to compare automatic-speed-controlled flying and two versions of our teleportation method with automatic distance control, one incorporating optical flow cues. We found that point-and-teleport with optical flow cues and automatic distance control was more accurate than flying with automatic speed control, and both were equally preferred to point-and-teleport without the cues.},
	urldate = {2020-12-14},
	booktitle = {26th {ACM} {Symposium} on {Virtual} {Reality} {Software} and {Technology}},
	publisher = {Association for Computing Machinery},
	author = {Lee, Jong-In and Asente, Paul and Kim, Byungmoon and Kim, Yeojin and Stuerzlinger, Wolfgang},
	month = nov,
	year = {2020},
	keywords = {Automatic control, multiscale virtual environments, Point-and-teleport, VR navigation},
	pages = {1--10}
}

@article{drogemuller_vrige_2017,
	title = {{VRige}: {Exploring} {Social} {Network} {Interactions} in {Immersive} {Virtual} {Environments}},
	shorttitle = {{VRige}},
	url = {http://rgdoi.net/10.13140/RG.2.2.34201.67689},
	doi = {10.13140/RG.2.2.34201.67689},
	abstract = {Analysis of social networks is an active research area for a large number of fields. Whilst advances in machine learning provided analysts with a wider range of automated tools, there still remains a significant amount of analysis that is performed through the visualisation of the networks. Visualization allows the user to identify clusters, patterns, and anomalies within a dataset. In this paper we introduce VRige, a virtual reality system for visualization, exploration, and tagging of social networks design in Unity 3D. Our new system allows for the exploration both the connections between entities and the entity attributes. In this paper we provide an overview of VRige, the visualization design, interactions, and system design. We also describe a number optimizations we made in order to support a system such as this in Unity 3D.},
	language = {en},
	urldate = {2021-01-22},
	author = {Drogemuller, Adam and Cunningham, Andrew and Walsh, James A. and Ross, William and Thomas, Bruce H.},
	year = {2017},
}

@inproceedings{yi-jheng_huang_gesture_2017,
	title = {A gesture system for graph visualization in virtual reality environments},
	doi = {10.1109/PACIFICVIS.2017.8031577},
	abstract = {As virtual reality (VR) hardware technology becomes more mature and affordable, it is timely to develop visualization applications making use of such technology. How to interact with data in an immersive 3D space is both an interesting and challenging problem, demanding more research investigations. In this paper, we present a gesture input system for graph visualization in a stereoscopic 3D space. We compare desktop mouse input with gesture input with bare hands for performing a set of tasks on graphs. Our study results indicate that users are able to effortlessly manipulate and analyze graphs using gesture input. Furthermore, the results also show that using gestures is more efficient when exploring the complicated graph.},
	booktitle = {2017 {IEEE} {Pacific} {Visualization} {Symposium} ({PacificVis})},
	author = {{Yi-Jheng Huang} and Fujiwara, T. and {Yun-Xuan Lin} and {Wen-Chieh Lin} and {Kwan-Liu Ma}},
	month = apr,
	year = {2017},
	note = {ISSN: 2165-8773},
	keywords = {virtual reality, Data visualization, data visualisation, Visualization, graph visualization, Three-dimensional displays, Two dimensional displays, graph theory, Mice, Electronic mail, gesture system, H.5.2 [Information Systems]: Information Interfaces and Presentation—User Interfaces, Resists, stereoscopic 3D space, VR},
	pages = {41--45}
}

@misc{bostock_d3forcejs_nodate,
	title = {d3-force - https://github.com/d3/d3-force},
	url = {https://github.com/d3/d3-force},
	abstract = {This module implements a velocity Verlet numerical integrator for simulating physical forces on particles.},
	urldate = {2021-01-30},
	author = {Bostock, Mike},
	year = {2021},
	month = jan,
}

@article{archambault_grouseflocks_2008,
	title = {{GrouseFlocks}: {Steerable} {Exploration} of {Graph} {Hierarchy} {Space}},
	volume = {14},
	shorttitle = {{GrouseFlocks}},
	doi = {10.1109/TVCG.2008.34},
	abstract = {Several previous systems allow users to interactively explore a large input graph through cuts of a superimposed hierarchy. This hierarchy is often created using clustering algorithms or topological features present in the graph. However, many graphs have domain-specific attributes associated with the nodes and edges, which could be used to create many possible hierarchies providing unique views of the input graph. GrouseFlocks is a system for the exploration of this graph hierarchy space. By allowing users to see several different possible hierarchies on the same graph, the system helps users investigate graph hierarchy space instead of a single fixed hierarchy. GrouseFlocks provides a simple set of operations so that users can create and modify their graph hierarchies based on selections. These selections can be made manually or based on patterns in the attribute data provided with the graph. It provides feedback to the user within seconds, allowing interactive exploration of this space.},
	journal = {IEEE Transactions on Visualization and Computer Graphics},
	author = {Archambault, Daniel and Munzner, Tamara and Auber, David},
	month = jul,
	year = {2008},
	pages = {900--13}
}

@misc{aframe,
	title = {A-FRAME -  https://aframe.io/},
	url = {https://aframe.io/},
	abstract = {A web framework for building 3D/AR/VR experiences},
	urldate = {2021-02-21},
	author = {Supermedium (Super XYZ Inc.)},
	year = {2021},
	month = feb,
}

@misc{threejs,
	title = {three.js - https://threejs.org/},
	url = {https://threejs.org/},
	abstract = {The aim of the project is to create an easy to use, lightweight, 3D library with a default WebGL renderer. The library also provides Canvas 2D, SVG and CSS3D renderers in the examples.},
	urldate = {2021-02-21},
	author = {three.js - open source contributors},
	year = {2021},
	month = feb,
}

@misc{thesisWebsite,
	title = {3dmultilayer.emanum.dev},
	url = {https://3dmultilayer.emanum.dev},
	abstract = {Website that contains a demo of our visualization as well as a short introduction to the topic.},
	urldate = {2021-03-06},
	author = {Manuel Eiweck},
	year = {2021},
	month = mar,
}

@inproceedings{vehlow_state_2015,
	title = {The {State} of the {Art} in {Visualizing} {Group} {Structures} in {Graphs}},
	doi = {10.2312/eurovisstar.20151110},
	abstract = {Graph visualizations encode relationships between objects. Abstracting the objects into group structures provides an overview of the data. Groups can be disjoint or overlapping, and might be organized hierarchically. However, the underlying graph still needs to be represented for analyzing the data in more depth. This work surveys research in visualizing group structures as part of graph diagrams. A particular focus is the explicit visual encoding of groups, rather than only using graph layout to implicitly indicate groups. We introduce a taxonomy of visualization techniques structuring the field into four main categories: visual node attributes vary properties of the node representation to encode the grouping, juxtaposed approaches use two separate visualizations, superimposed techniques work with two aligned visual layers, and embedded visualizations tightly integrate group and graph representation. We discuss results from evaluations of those techniques as well as main areas of application. Finally, we report future challenges based on interviews we conducted with leading researchers of the field.},
	author = {Vehlow, Corinna},
	month = jan,
	year = {2015}
}

@inproceedings{greffard_visual_2012,
	address = {Berlin, Heidelberg},
	series = {Lecture {Notes} in {Computer} {Science}},
	title = {Visual {Community} {Detection}: {An} {Evaluation} of {2D}, {3D} {Perspective} and {3D} {Stereoscopic} {Displays}},
	isbn = {978-3-642-25878-7},
	shorttitle = {Visual {Community} {Detection}},
	doi = {10.1007/978-3-642-25878-7_21},
	abstract = {3D drawing problems of the 90’s were essentially restricted on representations in 3D perspective. However, recent technologies offer 3D stereoscopic representations of high quality which allow the introduction of binocular disparities, which is one of the main depth perception cues, not provided by the 3D perspective. This paper explores the relevance of stereoscopy for the visual identification of communities, which is a task of great importance in the analysis of social networks. A user study conducted on 35 participants with graphs of various complexity shows that stereoscopy outperforms 3D perspective in the vast majority of the cases. When comparing stereoscopy with 2D layouts, the response time is significantly lower for 2D but the quality of the results closely depend on the graph complexity: for a large number of clusters and a high probability of cluster overlapping stereoscopy outperforms 2D whereas for simple structures 2D layouts are more efficient.},
	language = {en},
	booktitle = {Graph {Drawing}},
	publisher = {Springer},
	author = {Greffard, Nicolas and Picarougne, Fabien and Kuntz, Pascale},
	editor = {van Kreveld, Marc and Speckmann, Bettina},
	year = {2012},
	keywords = {Binocular Disparity, Community Detection, Graph Drawing, Inter Cluster Link, Straight Line Drawing},
	pages = {215--225}
}

@inproceedings{kotlarek_study_2020,
	title = {A {Study} of {Mental} {Maps} in {Immersive} {Network} {Visualization}},
	doi = {10.1109/PacificVis48177.2020.4722},
	abstract = {The visualization of a network influences the quality of the mental map that the viewer develops to understand the network. In this study, we investigate the effects of a 3D immersive visualization environment compared to a traditional 2D desktop environment on the comprehension of a network's structure. We compare the two visualization environments using three tasks-interpreting network structure, memorizing a set of nodes, and identifying the structural changes-commonly used for evaluating the quality of a mental map in network visualization. The results show that participants were able to interpret network structure more accurately when viewing the network in an immersive environment, particularly for larger networks. However, we found that 2D visualizations performed better than immersive visualization for tasks that required spatial memory.},
	booktitle = {2020 {IEEE} {Pacific} {Visualization} {Symposium} ({PacificVis})},
	author = {Kotlarek, J. and Kwon, O. and Ma, K. and Eades, P. and Kerren, A. and Klein, K. and Schreiber, F.},
	month = jun,
	year = {2020},
	keywords = {Empirical studies in visualization, Graph drawings, Human-centered computing, Visualization, Visualization techniques},
	pages = {1--10}
}

@incollection{marriott_immersive_2018,
	address = {Cham},
	series = {Lecture {Notes} in {Computer} {Science}},
	title = {Immersive {Analytics}: {Time} to {Reconsider} the {Value} of {3D} for {Information} {Visualisation}},
	isbn = {978-3-030-01388-2},
	shorttitle = {Immersive {Analytics}},
	url = {https://doi.org/10.1007/978-3-030-01388-2_2},
	abstract = {Modern virtual reality display technologies engender spatial immersion by using a variety of depth cues such as perspective and head-tracked binocular presentation to create visually realistic 3D worlds. While 3D visualisations are common in scientific visualisation, they are much less common in information visualisation. In this chapter we explore whether immersive analytic applications should continue to use traditional 2D information visualisations or whether there are situations when 3D may offer benefits. We identify a number of potential applications of 3D depth cues for abstract data visualisation: using depth to show an additional data dimension, such as in 2.5D network layouts, views on non-flat surfaces and egocentric views in which the data is placed around the viewer, and visualising abstract data with a spatial embedding. Another important potential benefit is the ability to arrange multiple views in the 3D space around the user and to attach abstract visualisations to objects in the real world.},
	language = {en},
	urldate = {2021-04-14},
	booktitle = {Immersive {Analytics}},
	publisher = {Springer International Publishing},
	author = {Marriott, Kim and Chen, Jian and Hlawatsch, Marcel and Itoh, Takayuki and Nacenta, Miguel A. and Reina, Guido and Stuerzlinger, Wolfgang},
	editor = {Marriott, Kim and Schreiber, Falk and Dwyer, Tim and Klein, Karsten and Riche, Nathalie Henry and Itoh, Takayuki and Stuerzlinger, Wolfgang and Thomas, Bruce H.},
	year = {2018},
	doi = {10.1007/978-3-030-01388-2_2},
	keywords = {3D, Data visualisation, Immersive analytics, Information visualisation},
	pages = {25--55}
}

@article{ware_evaluating_1996,
	title = {Evaluating stereo and motion cues for visualizing information nets in three dimensions},
	volume = {15},
	issn = {0730-0301},
	url = {https://doi.org/10.1145/234972.234975},
	doi = {10.1145/234972.234975},
	abstract = {This article concerns the benefits of presenting abstract data in 3D. Two experiments show that motion cues combined with stereo viewing can substantially increase the size of the graph that can be preceived. The first experiment was designed to provide quantitiative measurements of how much more (or less) can be understood in 3D than in 2D. The 3D display used was configured so that the image on the monitor was coupled to the user's actual eye positons (and it was updated in real-time as the user moved) as well as bring in stereo. Thus the effect was like a local “virtual reality” display located in the vicinity of the computer monitor. The results from this study show that head-coupled stereo viewing can increase the size of an abstract graph that can be understood by a factor of three; using stereo alone provided an increase by a factor of 1.6 and head coupling along produced an increase by a factor of 2.2. The second experiment examined a variety of motion cues provided by head-coupled perspective (as in virtual reality displays), head-guided motion and automatic rotation, respectively, both with and without stereo in each case. The results show that structured 3D motion and stereo viewing both help in understanding, but that the kind of motion is not particularly important; all improve performance, and all are more significant than stereo cues. These results provide strong reasons for using advanced 3D graphics for interacting with a large variety of information structures.},
	number = {2},
	urldate = {2021-04-14},
	journal = {ACM Transactions on Graphics},
	author = {Ware, Colin and Franck, Glenn},
	month = apr,
	year = {1996},
	keywords = {virtual reality, information visualization, head-coupled display, network visualization, stereopsis},
	pages = {121--140}
}