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33
Visualizing Dynamic Data with Maps
"... Maps offer a familiar way to present geographic data (continents, countries), and additional information (topography, geology),can be displayed with the help of contours and heatmap overlays. In this paper we consider visualizing largescale dynamic relational data by taking advantage of the geogra ..."
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Maps offer a familiar way to present geographic data (continents, countries), and additional information (topography, geology),can be displayed with the help of contours and heatmap overlays. In this paper we consider visualizing largescale dynamic relational data by taking advantage of the geographic map metaphor. We describe a system that visualizes user traffic on the Internet radio station last.fm and address challenges in mental map preservation, as well as issues in animated mapbased visualization. 1
On maximum differential graph coloring
 In 18th Symp. on Graph Drawing (GD
, 2010
"... Abstract. We study the maximum differential graph coloring problem, in which the goal is to find a vertex labeling for a given undirected graph that maximizes the label difference along the edges. This problem has its origin in map coloring, where not all countries are necessarily contiguous. We def ..."
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Abstract. We study the maximum differential graph coloring problem, in which the goal is to find a vertex labeling for a given undirected graph that maximizes the label difference along the edges. This problem has its origin in map coloring, where not all countries are necessarily contiguous. We define the differential chromatic number and establish the equivalence of the maximum differential coloring problem to that of kHamiltonian path. As computing the maximum differential coloring is NPComplete, we describe an exact backtracking algorithm and a spectralbased heuristic. We also discuss lower bounds and upper bounds for the differential chromatic number for several classes of graphs. 1
Visualizing Streaming Text Data with Dynamic Graphs and Maps
"... Abstract. The many endless rivers of text now available present a serious challenge in the task of gleaning, analyzing and discovering useful information. In this paper, we describe a methodology for visualizing text streams in realtime modeled as a dynamic graph and its derived map. The approach a ..."
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Cited by 5 (1 self)
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Abstract. The many endless rivers of text now available present a serious challenge in the task of gleaning, analyzing and discovering useful information. In this paper, we describe a methodology for visualizing text streams in realtime modeled as a dynamic graph and its derived map. The approach automatically groups similar messages into “countries, ” with keyword summaries, using semantic analysis, graph clustering and map generation techniques. It handles the need for visual stability across time by dynamic graph layout and Procrustes projection techniques, enhanced with a novel stable component packing algorithm. The result provides a continuous, succinct view of evolving topics of interest. To make these ideas concrete, we describe their application to an online service called TwitterScope. 1
ImPrEd: An Improved ForceDirected Algorithm that Prevents Nodes from Crossing Edges
, 2011
"... PrEd [Ber00] is a forcedirected algorithm that improves the existing layout of a graph while preserving its edge crossing properties. The algorithm has a number of applications including: improving the layouts of planar graph drawing algorithms, interacting with a graph layout, and drawing Eulerli ..."
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PrEd [Ber00] is a forcedirected algorithm that improves the existing layout of a graph while preserving its edge crossing properties. The algorithm has a number of applications including: improving the layouts of planar graph drawing algorithms, interacting with a graph layout, and drawing Eulerlike diagrams. The algorithm ensures that nodes do not cross edges during its execution. However, PrEd can be computationally expensive and overlyrestrictive in terms of node movement. In this paper, we introduce ImPrEd: an improved version of PrEd that overcomes some of its limitations and widens its range of applicability. ImPrEd also adds features such as flexible or crossable edges, allowing for greater control over the output. Flexible edges, in particular, can improve the distribution of graph elements and the angular resolution of the input graph. They can also be used to generate Euler diagrams with smooth boundaries. As flexible edges increase data set size, we experience an execution/drawing quality trade off. However, when flexible edges are not used, ImPrEd proves to be consistently faster than PrEd. Categories and Subject Descriptors (according to ACM CCS): G.2.2 [Discrete Mathematics]: Graph Theory—Graph Algorithms
Node, NodeLink, and NodeLinkGroup Diagrams: An Evaluation
"... Abstract—Effectively showing the relationships between objects in a dataset is one of the main tasks in information visualization. Typically there is a welldefined notion of distance between pairs of objects, and traditional approaches such as principal component analysis or multidimensional scali ..."
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Abstract—Effectively showing the relationships between objects in a dataset is one of the main tasks in information visualization. Typically there is a welldefined notion of distance between pairs of objects, and traditional approaches such as principal component analysis or multidimensional scaling are used to place the objects as points in 2D space, so that similar objects are close to each other. In another typical setting, the dataset is visualized as a network graph, where related nodes are connected by links. More recently, datasets are also visualized as maps, where in addition to nodes and links, there is an explicit representation of groups and clusters. We consider these three Techniques, characterized by a progressive increase of the amount of encoded information: node diagrams, nodelink diagrams and nodelinkgroup diagrams. We assess these three types of diagrams with a controlled experiment that covers nine different tasks falling broadly in three categories: nodebased tasks, networkbased tasks and groupbased tasks. Our findings indicate that adding links, or links and group representations, does not negatively impact performance (time and accuracy) of nodebased tasks. Similarly, adding group representations does not negatively impact the performance of networkbased tasks. Nodelinkgroup diagrams outperform the others on groupbased tasks. These conclusions contradict results in other studies, in similar but subtly different settings. Taken together, however, such results can have significant implications for the design of standard and domain specific visualizations tools. Index Terms—graphs, networks, maps, scatter plots 1
Maps of Computer Science
"... We describe a practical approach for visual exploration of research papers. Specifically, we use the titles of papers from the DBLP database to create what we call maps of computer science (MoCS). Words and phrases from the paper titles are the cities in the map, and countries are created based on w ..."
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We describe a practical approach for visual exploration of research papers. Specifically, we use the titles of papers from the DBLP database to create what we call maps of computer science (MoCS). Words and phrases from the paper titles are the cities in the map, and countries are created based on word and phrase similarity, calculated using cooccurence. With the help of heatmaps, we can visualize the profile of a particular conference or journal over the base map. Similarly, heatmap profiles can be made of individual researchers or groups such as a department. The visualization system also makes it possible to change the data used to generate the base map. For example, a specific journal or conference can be used to generate the base map and then the heatmap overlays can be used to show the evolution of research topics in the field over the years. As before, individual researchers or research groups profiles can be visualized using heatmap overlays but this time over the journal or conference base map. Finally, research papers or abstracts easily generate visual abstracts giving a visual representation of the distribution of topics in the paper. We outline a modular and extensible system for term extraction using natural language processing
Interactive Visualization of Streaming Text Data with Dynamic Maps
"... The many endless rivers of text now available present a serious challenge in the task of gleaning, analyzing and discovering useful information. In this paper, we describe a methodology for visualizing a text stream in realtime, modeled as a dynamic graph and its derived map. The approach automatic ..."
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Cited by 2 (0 self)
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The many endless rivers of text now available present a serious challenge in the task of gleaning, analyzing and discovering useful information. In this paper, we describe a methodology for visualizing a text stream in realtime, modeled as a dynamic graph and its derived map. The approach automatically groups similar messages into clusters displayed as “countries,” with keyword summaries, using semantic analysis, graph clustering and map generation techniques. It handles the need for visual stability across time by dynamic graph layout and Procrustes projection, enhanced with a novel stable component packing algorithm. The result provides a continuous, succinct view of everchanging topics of interest. To make these ideas concrete, we describe their application to an experimental web service called TwitterScope.
ENABLING MASSIVE PARALLELISM FOR TWOSTAGE STOCHASTIC INTEGER OPTIMIZATIONS A BRANCH AND BOUND BASED APPROACH
, 2011
"... DoD’s transportation activities incur USD 11+Billion expenditure anually. Optimal resource allocation under uncertainty provides huge opportunity for improvement and commensurate cost savings. Stochastic optimization techniques are used to incorporate uncertainty in the data to arrive at robust reso ..."
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Cited by 2 (2 self)
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DoD’s transportation activities incur USD 11+Billion expenditure anually. Optimal resource allocation under uncertainty provides huge opportunity for improvement and commensurate cost savings. Stochastic optimization techniques are used to incorporate uncertainty in the data to arrive at robust resource allocations. The application of stochastic optimization extends to a broad range of areas ranging from finance to production to economics to energy systems planning. We study the DoD Air Mobility Command’s airfleet assignment problem that schedules 1300+ aircrafts to deal with combat delivery, strategic airlift, air refueling, aeromedical evacuation operations, etc. around the world. Our formulation of the airfleet allocation problem for a small time horizon shows that annual average cost benefits of 3 % can be obtained by using stochastic integer optimization. Despite the potential cost benefits, use of stochastic integer optimization has remained intractable because the computational complexity of the problem prevents rapid decisions. Modern supercomputers can attain performance of several petaflops and hence can enhance
MapSets: Visualizing Embedded and Clustered Graphs
"... Abstract. We describe MapSets, a method for visualizing embedded and clustered graphs. The proposed method relies on a theoretically sound geometric algorithm which guarantees the contiguity and disjointness of the regions representing the clusters, and also optimizes the convexity of the regions. A ..."
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Abstract. We describe MapSets, a method for visualizing embedded and clustered graphs. The proposed method relies on a theoretically sound geometric algorithm which guarantees the contiguity and disjointness of the regions representing the clusters, and also optimizes the convexity of the regions. A fully functional implementation is available online and is used in a comparison with related earlier methods. 1
Temporal Multivariate Networks
"... Abstract. Networks that evolve over time, or dynamic graphs, have been of interest to the areas of information visualization and graph drawing for many years. Typically, its the structure of the dynamic graph that evolves as vertices and edges are added or removed from the graph. In a multivariate ..."
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Abstract. Networks that evolve over time, or dynamic graphs, have been of interest to the areas of information visualization and graph drawing for many years. Typically, its the structure of the dynamic graph that evolves as vertices and edges are added or removed from the graph. In a multivariate scenario, however, attributes play an important role and can also evolve over time. In this chapter, we characterize and survey methods for visualizing temporal multivariate networks. We also explore future applications and directions for this emerging area in the fields of information visualization and graph drawing. 1