Gregory Shirah - Academia.edu (original) (raw)

Papers by Gregory Shirah

Online Journal of Space Communication, 2003

Journey inside Hurricane Maria two days before it devastated Puerto Rico. This visualization is b... more Journey inside Hurricane Maria two days before it devastated Puerto Rico. This visualization is based on volumetric precipitation data from the NASA-Japan Global Precipitation Measurement Core Observatory satellite. The 3D tour reveals structures inside the hurricane that fueled the storm's intensification to a Category 5 within 24 hours.

IEEE Visualization, Oct 27, 2002

This paper examines a series of NASA outreach visualizations created using several layers of remo... more This paper examines a series of NASA outreach visualizations created using several layers of remote sensing satellite data ranging from 4-kilometers per pixel to 1-meter per pixel. The viewer is taken on a seamless, cloud free journey from a global view of the Earth down to ground level where buildings, streets, and cars are visible. The visualizations were produced using

“Towers in the Tempest” communicates recent scientific research into how hurricanes intensify. Th... more “Towers in the Tempest” communicates recent scientific research into how hurricanes intensify. This intensification can be caused by a phenomenon called a “hot tower.” For the first time, research meteorologists have run complex atmospheric simulations at a very fine temporal resolution of three minutes. Combining this simulation data with satellite observations enables detailed study of “hot towers.”

International Journal of Technology and Human Interaction, Apr 1, 2006

Most computer applications feature visual user interfaces that assume that all users have equival... more Most computer applications feature visual user interfaces that assume that all users have equivalent propensities to perceive, interpret, and understand the multidimensional spatial properties and relationships of the objects presented. However, the hunter-gatherer theory (Silverman & Eals, 1992) suggests that there are modern-day differences between the genders in spatial and cognitive abilities that stem from differentiated prehistoric sex roles. If true, there may be discrepancies in how males and females differentially utilize particular spatial visual cues and interface features. We report three experiments in which participants engage in visual spatial tasks using 2D and 3D virtual worlds: (1) matching object shapes; (2) positioning objects; and (3) resizing objects. Female subjects under-perform male subjects in the matching and positioning experiments, but they outperform male subjects in the resizing experiment. Moreover, male subjects make more use of motion cues. Implications for the design of gender-effective user interfaces and virtual environments are considered.

International journal of human-computer studies, Nov 1, 1997

Previous studies have demonstrated that motion cues combined with stereoscopic viewing can enhanc... more Previous studies have demonstrated that motion cues combined with stereoscopic viewing can enhance the perception of three-dimensional objects displayed on a twodimensional computer screen. Using a variant of the mental rotation paradigm, subjects view pairs of object images presented on a computer terminal and judge whether the objects are the same or different. The effects of four variables on the accuracy and speed of decision performances are assessed: stereo vs. mono viewing, controlled vs. uncontrolled object motion, cube vs. sphere construction and wire frame vs. solid surface characteristic. Viewing the objects as three-dimensional images results in more accurate and faster decision performances. Furthermore, accuracy improves although response time increases when subjects control the object motion. Subjects are equally accurate comparing wire frame and solid images, although they take longer comparing wire frame images. The cube-based or sphere-based object construction has no impact on decision accuracy nor response time.

This scientific visualization shows the intricate orbits of NASA's fleet of solar-observing s... more This scientific visualization shows the intricate orbits of NASA's fleet of solar-observing spacecraft using accurate relative positions and velocities of spacecraft, planetary bodies, and stars, illustrating vast ranges of spatial and temporal scales.

Lecture Notes in Computer Science, 2005

The ever-increasing power and complexity of available hardware and software has enabled the devel... more The ever-increasing power and complexity of available hardware and software has enabled the development of a wide variety of visualization techniques that allow the ever more concise presentation of data. Associated with this trend is the challenge to condense and convey ever-increasing amounts of useful information into smaller and smaller spaces. Depicting computer-generated visualizations in three dimensions (3D), similar to how we perceive the real world, is one approach to condense these visual presentations of information. However, there is an inherent dilemma in this approach; the visual medium on which the vast majority of 3D imagery is displayed is inherently two dimensional (2D): a flat computer monitor. Although there are some immersive or ‘true 3D devices' on the market, such as the fishbow rotating display, the LCD layered 3D monitor, and 3D displays marketed by companies such as SeeReal Technologies, most of these devices are either too small or too expensive for the average user.

IEEE transactions on systems, man, and cybernetics, Jul 1, 2004

More powerful computer hardware and software has enabled the development of numerous depth-cue te... more More powerful computer hardware and software has enabled the development of numerous depth-cue techniques to depict the three-dimensional (3-D) characteristics of computer-generated imagery. Particularly, the role of stereoscopic viewing in promoting the depth perception of objects in 3-D space has been widely studied. However, there has been little study of the use of cast shadows in this context, and few investigations of how computer-generated depth cues are perceptually integrated. To investigate these issues, subjects: 1) position a sphere to complete a directional vector/vector segment extending in space and 2) resize a sphere to match the perceived size of a second sphere displaced in space. Task accuracies and response times are recorded under the following conditions: 1) stereoscopic, and monoscopic, scene viewing; 2) objects casting zero, or one shadow; 3) flat, and zigzag , background surface shapes; and 4) solid and checkerboard background surface textures. The results suggest that, of the cues considered, stereo viewing has a consistently beneficial effect on positioning and resizing spheres in depth. However, objects casting shadows improve positioning accuracy to a level afforded by stereo viewing. Finally, more complex scene backgrounds impair positioning and resizing task performances. Implications for the design of effective 3-D user interfaces are discussed.

This extended abstract presents preliminary results of an experiment that explores the effects of... more This extended abstract presents preliminary results of an experiment that explores the effects of stereoscopic and monoscopic viewing, and controlled and uncontrolled motion, on the accuracy and speed of visually comparing and matching solid and wire frame cube-and sphere-based objects presented on a computer screen.

A contrast is drawn between the complex balance of global climate change issues using an accessib... more A contrast is drawn between the complex balance of global climate change issues using an accessible, familiar approach: a house of cards. Satellite images of the Earth are used with accessible themes such as sea ice and cloud patterns. The implication is that complexity realized in this piece was very slow in developing and that the construction was a very slow, tedious process. A future history is represented where many of the environmental underpinnings have already given way, allowing the observer to experience the null space where components have disappeared. How close is this future history to our present?

At NASA's Goddard Space Flight Center, faultisolation expert systems have been developed to suppo... more At NASA's Goddard Space Flight Center, faultisolation expert systems have been developed to support data monitoring and fault detection tasks in satellite control centers. Based on the lessons learned during these efforts in expert system automation, a new domain-specific expert system development tool named the Generic Spacecraft Analyst Assistant (GenSAA), was developed to facilitate the rapid development and reuse of real-time expert systems to serve as fault-isolation assistants for spacecraft analysts. This paper describes GenSAA's capabilities and how it is supporting monitoring functions of current and future NASA missions for a variety of satellite monitoring applications ranging from subsystem health and safety to spacecraft attitude. Finally, this paper addresses efforts to generalize GenSAA's data interface for more widespread usage throughout the space and commercial industry.

Capital Zoom is a seamless, cloudless, zoom-in starting from a global view zooming down to the na... more Capital Zoom is a seamless, cloudless, zoom-in starting from a global view zooming down to the nation's Capitol. It is composed entirely of real earth-observing satellite data. Included are IKONOS 1 meter data, Landsat7 15/30 meter data, Terra/MODIS 250 meter data, and Terra/MODIS 8 kilometer data. The visualization first zooms in seamlessly, then zooms out showing where the different data set layers reside.This vizualization was created using Maya for motion control, Renderman for rendering, IDL for pre-processing of the data, Imagine for image registration, and Photoshop for color martching. Copyright held by creator.

9th Computing in Aerospace Conference, Aug 22, 1993

For nearly twenty-five years, spacecraft missions have been operated in essentially the same mann... more For nearly twenty-five years, spacecraft missions have been operated in essentially the same manner: human operators monitor displays filled with alphanumeric text watching for limit violations or other indicators that signal a problem. The task is performed predominately by humans. Only in recent years have graphical user interfaces and expert systems been accepted within the control center environment to help reduce operator workloads. Unfortunately, the development of these systems is often time consuming and costly. At the NASA Goddard Space Flight Center (GSFC), a new domain specific expert system development tool called the Generic Spacecraft Analyst Assistant (GenSAA) has been developed. Through the use of a highly graphical user interface and point-and-click operation, GenSAA facilitates the rapid, 'programming-free' construction of intelligent graphical monitoring systems to serve as real-time, fault-isolation assistants for spacecraft analysts. Although specifically developed to support real-time satellite monitoring, GenSAA can support the development of intelligent graphical monitoring systems in a variety of space and commercial applications.

Online Journal of Space Communication, 2003

American Astronomical Society Meeting Abstracts, Dec 1, 2001

ACM SIGGRAPH 2017 Computer Animation Festival, 2017

Volumetric carbon dioxide concentrations vary from winter to summer. CO2 is high during northern ... more Volumetric carbon dioxide concentrations vary from winter to summer. CO2 is high during northern winter due to reduced photosynthesis. During spring and summer, photosynthesis increases as plants grow, reducing CO2 levels. These data are based on a synthesis of Orbiting Carbon Observatory-2 satellite data and the Goddard Earth Observing System model.

At NASA's Goddard Space Flight Center, fault-isolation expert systems have been developed to ... more At NASA's Goddard Space Flight Center, fault-isolation expert systems have been developed to support data monitoring and fault detection tasks in satellite control centers. Based on the lessons learned during these efforts in expert system automation, a new domain-specific expert system development tool named the Generic Spacecraft Analysts Assistant (GenSAA), was developed to facilitate the rapid development and reuse of real-time expert systems to serve as fault-isolation assistants for spacecraft analysts. This paper describes GenSAA's capabilities and how it is supporting monitoring functions of current and future NASA missions for a variety of satellite monitoring applications ranging from subsystem health and safety to spacecraft attitude. Finally, this paper addresses efforts to generalize GenSAA's data interface for more widespread usage throughout the space and commercial industry.

SIGGRAPH Asia 2019 Technical Briefs, 2019

In data-driven visualizations, the size and accessibility of data files can greatly impact the co... more In data-driven visualizations, the size and accessibility of data files can greatly impact the computer graphics production pipeline. Loading large and complex data structures into 3D animation software such as Maya may result in system performance issues that limit interactivity. At NASA's Scientific Visualization Studio, we have implemented methods to procedurally read data files and generate graphics at render time. We accomplish this by creating per-frame calls in our animation software that are executed by the renderer. This procedural workflow accelerates visualization production and iteration.

Online Journal of Space Communication, 2003

Journey inside Hurricane Maria two days before it devastated Puerto Rico. This visualization is b... more Journey inside Hurricane Maria two days before it devastated Puerto Rico. This visualization is based on volumetric precipitation data from the NASA-Japan Global Precipitation Measurement Core Observatory satellite. The 3D tour reveals structures inside the hurricane that fueled the storm's intensification to a Category 5 within 24 hours.

IEEE Visualization, Oct 27, 2002

This paper examines a series of NASA outreach visualizations created using several layers of remo... more This paper examines a series of NASA outreach visualizations created using several layers of remote sensing satellite data ranging from 4-kilometers per pixel to 1-meter per pixel. The viewer is taken on a seamless, cloud free journey from a global view of the Earth down to ground level where buildings, streets, and cars are visible. The visualizations were produced using

“Towers in the Tempest” communicates recent scientific research into how hurricanes intensify. Th... more “Towers in the Tempest” communicates recent scientific research into how hurricanes intensify. This intensification can be caused by a phenomenon called a “hot tower.” For the first time, research meteorologists have run complex atmospheric simulations at a very fine temporal resolution of three minutes. Combining this simulation data with satellite observations enables detailed study of “hot towers.”

International Journal of Technology and Human Interaction, Apr 1, 2006

Most computer applications feature visual user interfaces that assume that all users have equival... more Most computer applications feature visual user interfaces that assume that all users have equivalent propensities to perceive, interpret, and understand the multidimensional spatial properties and relationships of the objects presented. However, the hunter-gatherer theory (Silverman & Eals, 1992) suggests that there are modern-day differences between the genders in spatial and cognitive abilities that stem from differentiated prehistoric sex roles. If true, there may be discrepancies in how males and females differentially utilize particular spatial visual cues and interface features. We report three experiments in which participants engage in visual spatial tasks using 2D and 3D virtual worlds: (1) matching object shapes; (2) positioning objects; and (3) resizing objects. Female subjects under-perform male subjects in the matching and positioning experiments, but they outperform male subjects in the resizing experiment. Moreover, male subjects make more use of motion cues. Implications for the design of gender-effective user interfaces and virtual environments are considered.

International journal of human-computer studies, Nov 1, 1997

Previous studies have demonstrated that motion cues combined with stereoscopic viewing can enhanc... more Previous studies have demonstrated that motion cues combined with stereoscopic viewing can enhance the perception of three-dimensional objects displayed on a twodimensional computer screen. Using a variant of the mental rotation paradigm, subjects view pairs of object images presented on a computer terminal and judge whether the objects are the same or different. The effects of four variables on the accuracy and speed of decision performances are assessed: stereo vs. mono viewing, controlled vs. uncontrolled object motion, cube vs. sphere construction and wire frame vs. solid surface characteristic. Viewing the objects as three-dimensional images results in more accurate and faster decision performances. Furthermore, accuracy improves although response time increases when subjects control the object motion. Subjects are equally accurate comparing wire frame and solid images, although they take longer comparing wire frame images. The cube-based or sphere-based object construction has no impact on decision accuracy nor response time.

This scientific visualization shows the intricate orbits of NASA's fleet of solar-observing s... more This scientific visualization shows the intricate orbits of NASA's fleet of solar-observing spacecraft using accurate relative positions and velocities of spacecraft, planetary bodies, and stars, illustrating vast ranges of spatial and temporal scales.

Lecture Notes in Computer Science, 2005

The ever-increasing power and complexity of available hardware and software has enabled the devel... more The ever-increasing power and complexity of available hardware and software has enabled the development of a wide variety of visualization techniques that allow the ever more concise presentation of data. Associated with this trend is the challenge to condense and convey ever-increasing amounts of useful information into smaller and smaller spaces. Depicting computer-generated visualizations in three dimensions (3D), similar to how we perceive the real world, is one approach to condense these visual presentations of information. However, there is an inherent dilemma in this approach; the visual medium on which the vast majority of 3D imagery is displayed is inherently two dimensional (2D): a flat computer monitor. Although there are some immersive or ‘true 3D devices' on the market, such as the fishbow rotating display, the LCD layered 3D monitor, and 3D displays marketed by companies such as SeeReal Technologies, most of these devices are either too small or too expensive for the average user.

IEEE transactions on systems, man, and cybernetics, Jul 1, 2004

More powerful computer hardware and software has enabled the development of numerous depth-cue te... more More powerful computer hardware and software has enabled the development of numerous depth-cue techniques to depict the three-dimensional (3-D) characteristics of computer-generated imagery. Particularly, the role of stereoscopic viewing in promoting the depth perception of objects in 3-D space has been widely studied. However, there has been little study of the use of cast shadows in this context, and few investigations of how computer-generated depth cues are perceptually integrated. To investigate these issues, subjects: 1) position a sphere to complete a directional vector/vector segment extending in space and 2) resize a sphere to match the perceived size of a second sphere displaced in space. Task accuracies and response times are recorded under the following conditions: 1) stereoscopic, and monoscopic, scene viewing; 2) objects casting zero, or one shadow; 3) flat, and zigzag , background surface shapes; and 4) solid and checkerboard background surface textures. The results suggest that, of the cues considered, stereo viewing has a consistently beneficial effect on positioning and resizing spheres in depth. However, objects casting shadows improve positioning accuracy to a level afforded by stereo viewing. Finally, more complex scene backgrounds impair positioning and resizing task performances. Implications for the design of effective 3-D user interfaces are discussed.

This extended abstract presents preliminary results of an experiment that explores the effects of... more This extended abstract presents preliminary results of an experiment that explores the effects of stereoscopic and monoscopic viewing, and controlled and uncontrolled motion, on the accuracy and speed of visually comparing and matching solid and wire frame cube-and sphere-based objects presented on a computer screen.

A contrast is drawn between the complex balance of global climate change issues using an accessib... more A contrast is drawn between the complex balance of global climate change issues using an accessible, familiar approach: a house of cards. Satellite images of the Earth are used with accessible themes such as sea ice and cloud patterns. The implication is that complexity realized in this piece was very slow in developing and that the construction was a very slow, tedious process. A future history is represented where many of the environmental underpinnings have already given way, allowing the observer to experience the null space where components have disappeared. How close is this future history to our present?

At NASA's Goddard Space Flight Center, faultisolation expert systems have been developed to suppo... more At NASA's Goddard Space Flight Center, faultisolation expert systems have been developed to support data monitoring and fault detection tasks in satellite control centers. Based on the lessons learned during these efforts in expert system automation, a new domain-specific expert system development tool named the Generic Spacecraft Analyst Assistant (GenSAA), was developed to facilitate the rapid development and reuse of real-time expert systems to serve as fault-isolation assistants for spacecraft analysts. This paper describes GenSAA's capabilities and how it is supporting monitoring functions of current and future NASA missions for a variety of satellite monitoring applications ranging from subsystem health and safety to spacecraft attitude. Finally, this paper addresses efforts to generalize GenSAA's data interface for more widespread usage throughout the space and commercial industry.

Capital Zoom is a seamless, cloudless, zoom-in starting from a global view zooming down to the na... more Capital Zoom is a seamless, cloudless, zoom-in starting from a global view zooming down to the nation's Capitol. It is composed entirely of real earth-observing satellite data. Included are IKONOS 1 meter data, Landsat7 15/30 meter data, Terra/MODIS 250 meter data, and Terra/MODIS 8 kilometer data. The visualization first zooms in seamlessly, then zooms out showing where the different data set layers reside.This vizualization was created using Maya for motion control, Renderman for rendering, IDL for pre-processing of the data, Imagine for image registration, and Photoshop for color martching. Copyright held by creator.

9th Computing in Aerospace Conference, Aug 22, 1993

For nearly twenty-five years, spacecraft missions have been operated in essentially the same mann... more For nearly twenty-five years, spacecraft missions have been operated in essentially the same manner: human operators monitor displays filled with alphanumeric text watching for limit violations or other indicators that signal a problem. The task is performed predominately by humans. Only in recent years have graphical user interfaces and expert systems been accepted within the control center environment to help reduce operator workloads. Unfortunately, the development of these systems is often time consuming and costly. At the NASA Goddard Space Flight Center (GSFC), a new domain specific expert system development tool called the Generic Spacecraft Analyst Assistant (GenSAA) has been developed. Through the use of a highly graphical user interface and point-and-click operation, GenSAA facilitates the rapid, 'programming-free' construction of intelligent graphical monitoring systems to serve as real-time, fault-isolation assistants for spacecraft analysts. Although specifically developed to support real-time satellite monitoring, GenSAA can support the development of intelligent graphical monitoring systems in a variety of space and commercial applications.

Online Journal of Space Communication, 2003

American Astronomical Society Meeting Abstracts, Dec 1, 2001

ACM SIGGRAPH 2017 Computer Animation Festival, 2017

Volumetric carbon dioxide concentrations vary from winter to summer. CO2 is high during northern ... more Volumetric carbon dioxide concentrations vary from winter to summer. CO2 is high during northern winter due to reduced photosynthesis. During spring and summer, photosynthesis increases as plants grow, reducing CO2 levels. These data are based on a synthesis of Orbiting Carbon Observatory-2 satellite data and the Goddard Earth Observing System model.

At NASA's Goddard Space Flight Center, fault-isolation expert systems have been developed to ... more At NASA's Goddard Space Flight Center, fault-isolation expert systems have been developed to support data monitoring and fault detection tasks in satellite control centers. Based on the lessons learned during these efforts in expert system automation, a new domain-specific expert system development tool named the Generic Spacecraft Analysts Assistant (GenSAA), was developed to facilitate the rapid development and reuse of real-time expert systems to serve as fault-isolation assistants for spacecraft analysts. This paper describes GenSAA's capabilities and how it is supporting monitoring functions of current and future NASA missions for a variety of satellite monitoring applications ranging from subsystem health and safety to spacecraft attitude. Finally, this paper addresses efforts to generalize GenSAA's data interface for more widespread usage throughout the space and commercial industry.

SIGGRAPH Asia 2019 Technical Briefs, 2019

In data-driven visualizations, the size and accessibility of data files can greatly impact the co... more In data-driven visualizations, the size and accessibility of data files can greatly impact the computer graphics production pipeline. Loading large and complex data structures into 3D animation software such as Maya may result in system performance issues that limit interactivity. At NASA's Scientific Visualization Studio, we have implemented methods to procedurally read data files and generate graphics at render time. We accomplish this by creating per-frame calls in our animation software that are executed by the renderer. This procedural workflow accelerates visualization production and iteration.