Browsing by Subject "Information display systems"
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Item Development of a goal-driven analysis for requirements definition in hypertext information systems supporting complex-problem solving(Texas Tech University, 1999-05) Albers, Michael JoelWhen engaged in open-ended problem solving, the user must evaluate information from multiple sources. Unfortunately, people find it difficult to effectively search for and integrate multiple sources of information, requiring the system to provide the information in a manner which relates to the context of the problem. Also, rather than needing information in pre-defined ways, the viewing order and specific information requires changes with each problem. As a result, the methods used in conventional task analysis, which focus on defining the individual steps of a well-defined sequence, fail to provide good requirements for systems intended for supporting open-ended problem solving. Rather than focusing on individual steps, this dissertation develops a goal-driven analysis methodology based on defining and relating user's goals and information needs. Unlike a task-based analysis, the goal-driven analysis methodology revolves around uncovering the user's goals, the information needed to achieve those goals, and the contextual relationships between information elements. The analysis strives to uncover the major potential problem-solving paths and the information required to support following those paths, to provide the problem solver with varied routes to solving a specific problem. The unique feature of goal-driven analysis is that, throughout the methodology, it focuses on maintaining a connection between the user's goals, information needs, and problem context. This dissertation integrates the technical communication, cognitive psychology, and situation awareness literature, and explores the socio/cognitive aspects of information design as they relate to complex problem solving. It begins by arguing that effective information presentation requires a match between the user's mental model, the real-world context, and the factors which contribute to situation awareness. The dissertation then derives a four-step methodology: ethnography, interviews, scenario development, and group discussion, to develop a goal/information diagram which captures a graphical representation of the user's goals and information needs. The goal/information diagram then becomes the foundation for the analyst to use when developing system requirements. The dissertation also provides an extended example of how to perform a goal-driven analysis.Item Evaluation of an automated three-dimensional compensation algorithm for visual-display misalignment and effects of display formats in three-dimensional telerobor manipulation(Texas Tech University, 2000-08) Myung, SeonwanIn teleoperation environments, decision-making can be performed by a combination of knowledge-based autonomous procedures, sensor-based autonomous procedures, and/or the human operator. Humans can easily adapt to unpredictability in task environments, due to their superior problem solving skills and perceptual abilities. Therefore, using a human operator to make decisions is beneficial to the manual control of telerobot in real environments. When a robot is manually controlled in teleoperation, the control input of the operator is transmitted to the robot, and video cameras send visual feedback of the state of the robot to the operator. In this manner, the operator is engaged in the dynamic control of the robot. Some characteristics of this control have disadvantages. The visual feedback of remote manipulation by the video cameras requires a very high communication bandwidth to transmit the video signal. A small communication delay in control feedback deteriorates the teleoperation performance of the operator. The other disadvantage is due to spatial perturbations including depth problems and visual-display incompatibilities. Those perturbations can be reduced by training operators or using graphical aids. However, it usually takes a long time to get satisfying results through training, and most of the time it is very hard for operators to reach a satisfactory level of performance. The teleoperation visual system needs to provide sufficient visual information to allow various tasks to be accomplished. Understanding the relationship of the manipulator to some fixed reference plane is the basis for spatial orientation, and displaying control disorientation can result in degradation of operator performance as well as damage or loss of the manipulator. When multiple cameras or dynamically moving cameras are used in a manual operation, depending on the camera view angle, the axes of the manipulator are not aligned with the controller axes. This misalignment causes display-control incompatibility. Under the incompatibility conditions, the performance of the operator might be lower than the performance in compatibility conditions. In this research, 3-D automatic compensation method for visual-display compatibility was tested to reduce visual-display incompatibilities. Three different display formats with the 3-D compensation method were tested in telerobotic tracking simulation environments. The 3-D automatic compensation method can be applied to the display-control incompatibility conditions to reduce incompatibility. There is no need to change hardware settings for integrating the 3-D compensation method. In experiment I, the 3-D compensation method was integrated with the single display format. In experiment E, the 3-D compensation method was integrated with the three display formats and a visual mode. When the compensation method was used, performance was superior to the performance conditions in which the compensation method was not used. In addition, the single monitor with the 3-D compensation method saves cost by using a monitor and a low speed network connection as compared to using the multiple monitors. In each view, the operator works under display-control compatibility conditions, so that the operator freely select a good view without considering the display-control compatibility.Item The effects of display format and visual enhancement cues on performance of three-dimensional teleoperational tasks(Texas Tech University, 1998-05) Park, Sung HaDepth perception (as a third dimension) on a two-dimensional surface of a display interface very much determines the quality of the teleoperation system. In this research, among various teleoperation sensing requirements, the television depth requirement was investigated in detail. This research was intended to extend our understanding of the effects of visual display formats and visual enhancement cues on the ability of human operators to effectively control robot manipulators in three-dimensions. Visual display formats and visual enhancement cues were evaluated by employing a pick-and-place (picking up a virtual object and placing it into a storage rack) task in a simulated teleorobotic task environment. Three different display formats, a multiple 2-dimensional (2-D) display, a 3-dimensional (3-D) perspective display, and a 3-D stereoscopic display were simulated using a combination of various programming tools (external motif, C language, and TELEGRIP software) on a SiliconGraphics Indigo2 workstation. In order to aid human operators in perceiving depth, four different visual enhancement depth cues (including no enhancement cue) were also proposed and incorporated into each display format. Task difficulties were generated by manipulating the size of the storage rack. To compare different display formats and visual enhancement cues, various teleoperation performance measures were collected under each display condition. The measures included the time-to-completion, accuracy, subjective ratings of workload, and distance (move by the end effector). The results showed that the multiple 2-D display was superior to the perspective and stereoscopic displays, if no visual enhancement cues were provided. If provided with two of the proposed visual enhancement cues, the translucent reference cylinder and four reference lines, the stereoscopic and perspective displays were equivalent to the multiple 2-D display. The traditional single reference line was not sufficient to provide appropriate depth information on the stereoscopic and perspective displays. The stereoscopic display resulted in better performance than the perspective display only under the high task difficulty condition.