A Mental Workload Estimation Model for Visualization Using EEG

Various visualization design guides have been proposed and evaluated through quantitative methods that compare the response accuracy and time for completing visualization tasks. However, accuracy and time do not always represent the mental workload. Since quantitative approaches do not fully mirror mental workload, questionnaires and biosignals have been employed to measure mental workload in visualization assessments. The EEG as biosignal is one of the indicators frequently utilized to measure mental workload. Nevertheless, many studies have not applied the EEG for mental workload measurement in the visualization evaluation. In this work, we study the EEG to measure mental workload for visualization evaluation. We examine whether there is a difference in mental workload for the visualization designs suggested by the previously proposed visualization design guides. Besides, we propose a mental workload estimation model using EEG data specialized for each individual to evaluate visualization designs

Integrated process management in a parallel database programming environment

This thesis describes the design of a Knowledge-Based Software Engineering Environment (KBSEE) based on the framework of object-oriented knowledge base. The knowledge-based scheme provides us with a conceptually easy and powerful means to model software objects. The logical language of the knowledge base has enough descriptive power and generality to integrate the existing techniques and the knowledge of software engineering. KBSEE is an integrated software engineering environment which is designed mainly to relieve the user from designing and maintaining the low level details of programming activities. Given descriptions of processes (i.e., sequential processes, concurrent processes, and database processes), various techniques are applied to analyze and optimize the processes. A sequential process which is described logically or in a flowchart can be optimized through program transformations. A concurrent process can be defined as a set of sequential processes, coordination constraints, and integrity constraints. The definition is then proved correct either formally or informally (by using Petri net models). With an assimilation scheme for production rules, a design process can be performed incrementally. In this thesis, the problems of optimization and the concurrency control of database processes are also discussed

Gaze Behavior Effect on Gaze Data Visualization at Different Abstraction Levels

Many gaze data visualization techniques intuitively show eye movement together with visual stimuli. The eye tracker records a large number of eye movements within a short period. Therefore, visualizing raw gaze data with the visual stimulus appears complicated and obscured, making it difficult to gain insight through visualization. To avoid the complication, we often employ fixation identification algorithms for more abstract visualizations. In the past, many scientists have focused on gaze data abstraction with the attention map and analyzed detail gaze movement patterns with the scanpath visualization. Abstract eye movement patterns change dramatically depending on fixation identification algorithms in the preprocessing. However, it is difficult to find out how fixation identification algorithms affect gaze movement pattern visualizations. Additionally, scientists often spend much time on adjusting parameters manually in the fixation identification algorithms. In this paper, we propose a gaze behavior-based data processing method for abstract gaze data visualization. The proposed method classifies raw gaze data using machine learning models for image classification, such as CNN, AlexNet, and LeNet. Additionally, we compare the velocity-based identification (I-VT), dispersion-based identification (I-DT), density-based fixation identification, velocity and dispersion-based (I-VDT), and machine learning based and behavior-based modelson various visualizations at each abstraction level, such as attention map, scanpath, and abstract gaze movement visualization