Information theory assisted data visualization and exploration

This thesis introduces techniques to utilize information theory, particularly entropy for enhancing data visualization and exploration. The ultimate goal with this work is to enable users to perceive as much as information available for recognizing objects, detecting regular or non-regular patterns and reducing user effort while executing the required tasks. We believe that the metrics to be set for enhancing computer generated visualizations should be quantifiable and that quantification should measure the information perception of the user. The proper way to solve this problem is utilizing information theory, particularly entropy. Entropy offers quantification of the information amount in a general communication system. In the communication model, information sender and information receiver are connected with a channel. We are inspired from this model and exploited it in a different way, namely we set the information sender as the data to be visualized, the information receiver as the viewer and the communication channel as the screen where the visualized image is displayed. In this thesis we explore the usage of entropy in three different visualization problems, -Enhancing the visualization of large scale social networks for better perception, -Finding the best representational images of a 3D object to visually inspect with minimal loss of information, -Automatic navigation over a 3D terrain with minimal loss of information. Visualization of large scale social networks is still a major challenge for information visualization researchers. When a thousand nodes are displayed on the screen with the lack of coloring, sizing and filtering mechanisms, the users generally do not perceive much on the first look. They usually use pointing devices or keyboard for zooming and panning to find the information that they are looking for. With this thesis we tried to present a visualization approach that uses coloring, sizing and filtering to help the users recognize the presented information. The second problem that we tried to tackle is finding the best representational images of 3D models. This problem is highly subjective in cognitive manner. The best or good definitions do not depend on any metric or any quantification, furthermore, when the same image is presented to two different users it can be identified differently. However in this thesis we tried to map some metrics to best or good definitions for representational images, such as showing the maximum faces, maximum saliency or combination of both in an image. The third problem that we tried to find a solution is automatic terrain navigation with minimal loss of information. The information to be quantified on this problem is taken as the surface visibility of a terrain. However the visibility problem is changed with the heuristic that users generally focus on city centers, buildings and interesting points during terrain exploration. In order to improve the information amount at the time of navigation, we should focus on those areas. Hence we employed the road network data, and set the heuristic that intersections of road network segments are the residential places. In this problem, region extraction using road network data, viewpoint entropy for camera positions, and automatic camera path generation methods are investigated

Entropy Based Sensitivity Analysis and Visualization of Social Networks

Abstract. This paper introduces a technique to analyze and visualize a social network using Shannon's entropy model. We used degree entropy and presented novel measures such as, betweenness and closeness entropies to conduct network sensitivity analysis by means of evaluating the change of graph entropy via those measures. We integrated the result of our analyses into a visualization application where the social network is presented using node-link diagram. The size of visual representation of an actor depends on the amount of change in system entropy caused by the actor and color information is extracted from the graph clustering analysis. Filtering of edges and nodes is also provided to enable and improve the perception of complex graphs. The main contribution is that the information communicated from a social network is enhanced by means of sensitivity analyses and visualization techniques provided with this work

Design and test of the cross-format schema protocol (XFSP) for networked virtual environments

A Networked Virtual Environment (Net-VE) is a distributed software system in which multiple users interact with each other in real time even though these users may be located around the world [Zyda 99]. Net -VEs gained first attention through a variety of DOD and Academic research projects. After release of the multiplayer game DOOM, the gaming industry captured the idea of interactive multiplayer games. Today there are many popular Internet-based multiplayer games available. Effective networking of diverse entities and systems is a common problem for Networked Virtual Environments. In order to communicate with other entities a variety of communication protocols are used. Historically these communication protocols are "hard coded" into the software system and all nodes that participate in the environment must identically implement the protocols to interact with others. These communication protocols require authoring and compiling by a trained programmer. When the compiling process is introduced to the networked virtual environment, it detracts the extensibility and dynamicism of the system. This thesis presents the design and development of a Networked Virtual Environment model that uses Cross Format Schema Protocol (XFSP). With this work we show that a networked simulation can work for 24 hours a day and 7 days a week with an extensible schema based networking protocol and it is not necessary to hard code and compile the protocols into the networked virtual environments. Furthermore, this thesis presents a general automatic protocol handler for schema-defined XML document or message. Additionally, this work concludes with idea that protocols can be loaded and extended at runtime, and can be created with different-fidelity resolutions, resulting in swapping at runtime based on distributed state.http://archive.org/details/designndtestofcr109459872Lieutenant Junior Grade, Turkish NavyApproved for public release; distribution is unlimited

Entropy Assisted Automated Terrain Navigation using Traveling Salesman Problem

Abstract Navigation in 3D terrain is considered to be a challenging task and requires virtual camera control skills such as zooming, panning and tilting. Novice users can easily get distracted and disoriented that may result with lost in space. Methods to overcome the virtual environment exploration problems are still being researched to assist users during their journey inside virtual environments. Assisted camera control techniques require viewpoint computation and path planning. This paper introduces a novel approach to navigate over a 3D terrain with minimal loss of information. We exploit the concept of the Viewpoint Entropy for best view determination and use our Greedy N-Best View Selection for visibility calculations. We integrate road network data to extract regions for detailed visibility analysis in subsections of the terrain. In order to connect the calculated viewpoints an evolutionary programming approach for Traveling Salesman problem is used where the distance objective is minimized. The generated tour is presented using Google Earth framework for terrain exploration where we can get real data streams. The computed and planned viewpoints reduces human effort when used as starting points for scene exploration or generating the representative images of the terrain dataset. The proposed framework can be integrated into 3D game engines or any urban visualization system to give quick glimpse or tour of the environment for the novice users without the help of prior planning

Entropy based sensitivity analysis and visualization of social networks

This paper introduces a technique to analyze and visualize social networks using Shannon's entropy model. Entropy is exploited to measure the information amount in social network graphs, and to conduct sensitivity analyses. Novel measures such as degree, betweenness and closeness entropies are evaluated to find the change in graph entropy for the actors. In this work we present a visualization approach that uses coloring, sizing and filtering to help the users perceive the communicated information. The result of sensitivity analyses is integrated into the visualization using the change amount caused by the actors as information. The main contribution of this study is a visualization where the information communicated from a social network is enhanced by the help of sensitivity analyses

Representational image generation for 3D objects

Finding good representational images for 3D object exploration is a highly subjective problem in the cognitive field. The “best” or “good” definitions do not depend on any metric. We have explained the VKL distance concept and introduced a novel view descriptor called vSKL distance for finding “good” representational images. The image generation is done by projecting the surfaces of 3D objects onto the screen or any planar surface. The projection process depends on parameters such as camera position, camera vector, up vector, and clipping plane positions. In this work we present a technique to find such camera positions that the 3D object is projected in “good” or “best” way where those subjective definitions are mapped to Information Theoretical distances. We compared greedy view selection integrated vSKL with two well known techniques: VKL and VMI. vSKL performs very close to the other two, hence face coverage perturbation is minimal, but it is 3 to 4 times faster. Furthermore, the saliency information is conveyed to users with generated images

Investigation of the fracture energy of hot mixtures asphalt incorporating metallic wastes via semi-circular bending test

In the study, metallic wastes were evaluated in order to reduce environmental impacts and to contribute fracture energy of HMA mixtures. In this context, aluminum chips and iron powders were included in the mixtures at 0.50%, 1.00%, and 1.50% (by weight of mixtures), and the effect of HMA mixtures on fracture energy was investigated by Semi-Circular Bending (SCB) test. Experiments were performed on a total of 28 SCB test specimens from 7 different series including reference, Al-0.50, Al-1.00, Al-1.50, Fe-0.50, Fe-1.00, Fe-1.50. Basic physical properties, dissipated energy (DE), fracture energy (G(f)), flexibility index (FI), and crack resistance index (CRI) values of HMA specimens were measured and compared. Based on test results, carrying load capacity and G(f) values of the mixtures were increased in the use of waste iron powders. A decrease in G(f) and peak load values were obtained while increasing the aluminum chips ratios. However, with the use of 0.5% waste aluminum chips were contributed G(f), peak load, CRI, and FI values compared by the reference sample. It is concluded that both aluminum chips and iron powders contributed to fracture energy of HMA mixtures. (C) 2021 Elsevier Ltd. All rights reserved.WOS:0006874795000012-s2.0-8510862255