Joa Sang Lim

Preparing computers for affective communication: a psychophysiological concept and preliminary results.

Despite rapid advances in technology, computers remain incapable of responding to human emotions. An exploratory study was conducted to find out what physiological parameters might be useful to differentiate among 4 emotional states, based on 2 dimensions: pleasantness versus unpleasantness and arousal versus relaxation. The 4 emotions were induced by exposing 26 undergraduate students to different combinations of olfactory and auditory stimuli, selected in a pretest from 12 stimuli by subjective ratings of arousal and valence. Changes in electroencephalographic (EEG), heart rate variability, and electrodermal measures were used to differentiate the 4 emotions. EEG activity separates pleasantness from unpleasantness only in the aroused but not in the relaxed domain, where electrodermal parameters are the differentiating ones. All three classes of parameters contribute to a separation between arousal and relaxation in the positive valence domain, whereas the latency of the electrodermal response is the only differentiating parameter in the negative domain. We discuss how such a psychophysiological approach may be incorporated into a systemic model of a computer responsive to affective communication from the user.

An empirical investigation of the impact of the object-oriented paradigm on the maintainability of real-world mission-critical software

Empirical evidence for the maintainability of object-oriented systems is far from conclusive, partly due to the lack of representativeness of the subjects and systems used in earlier studies. We empirically examined this issue for mission-critical software that was currently operational and maintained by software professionals. Two functionally equivalent versions of a credit approval system were maintained, one object oriented (OO) and the other non-object oriented (NOO). We found that the OO group took less time to maintain a greater number of software artifacts than its NOO counterpart. This difference held for all phases of the software development life cycle. This result was due to the usefulness of UML for impact analysis of the OO version, which contributed to effective comprehension and communication. Insufficient design specifications for the NOO version led to ambiguity and costly defects in transferring design solutions to development. Also, the encapsulation of the OO version appeared to reduce mental loads for maintenance tasks and resulted in code reuse. On the other hand, the number of files to be managed increased and, thus, dependency management was required for the OO version. Furthermore, despite much tuning, the OO version ran slower than its NOO counterpart. More field studies on software professionals are needed to compare contextual factors such as methods, processes, and maintenance tools.

Design and implementation of a fast integral image rendering method

The computer-generated integral imaging system is a way of showing stereoscopic displays that allows users to see 3D images without wearing any special glasses. In the integral imaging system, the 3D object information is stored as elemental images, which are generated by the image mapping method. This paper reviews the previous image mapping methods, such as PRR (Point Retracing Rendering), MVR (Multi-Viewpoint Rendering), and PGR (Parallel Group Rendering). Then, it explains a new image mapping method called VVR, which shows better performance while generating similar pictures as in MVR. Finally it mentions process of making the integral imaging system, and analyzes performance. Then, it discusses some research directions for the future improvement.

VISION-BASED GAZE ESTIMATION METHOD FOR STEREOSCOPIC DISPLAY SYSTEMS

Abstract In this paper, we propose a new near infra-red (IR) vision-based gaze tracking method, which is not affected by facial movements in stereoscopic virtual reality (VR) systems. Our proposed method has following five novelties compared to previous works. (i) By using our gaze tracker instead of a conventional input device, users felt more interested and immersed in the stereoscopic VR system, (ii) by using an IR light passing filter and an IR illuminator, we were able to implement a robust gaze tracker irrespective of environmental lighting conditions, (iii) we used the simple 2D based eye and face gaze estimation method without considering the complicated 3D structure and motion of human eye and face, which could reduce the system complexities, (iv) to prevent the unintended movement of gaze position by natural eye blinking, we discriminated the eye blinking by measuring pupil size. And this information was used for button clicking and mode toggling based on the analysis of users fatigue. That is, the measured fatigue information of user was used for the mode toggling between gaze tracking mode and the conventional mouse input mode, (v) the proposed method allowed the natural movement of users head by tracking the IR rhombus-shaped pattern, which was not affected by the change of environmental lighting. Experimental results showed that the gaze estimation accuracy of the proposed method was 0.98 degrees. In addition, the subjective tests showed that the VR application using the proposed method was more interesting and immersive to users than those using conventional input devices.

A study on non-intrusive facial and eye gaze detection

To detect accurate human gaze position is vey difficult, but important problem for many applications. For that, it is requisite to detect the facial and eye movement accurately and fastly. So, we implemented a real-time gaze tracking system based on facial and eye movement. The performance of detecting facial features could be enhanced by Support Vector Machine and the eye gaze position on a monitor could be generalized by a multi-layered perceptron. And two gaze positions were geometically summed and final gaze position was acquired. Experimental results showed that the RMS error of gaze detection is about 2.4 degrees (1.68 degrees on X axis and 1.71 degrees on Y axis at the Z distance of 50 cm).

Practical Gaze Point Detecting System

In this paper, we propose the new gaze detection system with dual cameras (a wide and a narrow view camera). In order to locate the user’s eye position accurately, the narrow-view camera has the functionalities of auto focusing/panning/tilting based on the detected 3D eye positions from the wide view camera. In addition, we use the IR-LED illuminators for wide and narrow view camera, which can ease the detecting of facial features, pupil and iris position. To overcome the problem of specular reflection on glasses by illuminator, we use dual IR-LED illuminators for wide and narrow view camera. Experimental results show that the gaze detection error between the computed positions and the real ones is about 2.89 cm of RMS error.

Effect of different modal feedback on attention recovery

This study aims to empirically examine the effect of feedback on attention recovery. The role of feedback has been proven to be positive in particular to extend the limitation of attention resource. We studied the impact of feedback on attention by varying its type and modality. An experimental system was developed to observe how accurately the participants performed the figure-matching task with differential feedback provided on a real-time basis based on the ADHD (attention deficit hyperactivity disorder) diagnostic model. Investigated in this study were two types of feedbacks (1) single feedback such as visual, auditory and tactile stimulus and (2) double feedback with two types of feedback. Eight university students participated in this study with six different feedback conditions and controlled conditions. The results showed that the tactile feedback and the combined tactile with visual feedback significantly contributed most to attention recovery and performance.

Development of a handheld user interface framework for virtual environments

This paper describes a design and implementation of a new handheld user interface framework called HIVE. HIVE provides the familiar 2D user interface on a mobile handheld computer to support user interactions in a virtual environment. It provides a scripting language based on XML and Lua to ease the development of handheld user interfaces and to increase the reusability of the interface components. This paper also discusses the use of the HIVE framework to develop a couple of handheld user interface applications for virtual environments to show usability.

Model and Process for Timely Progress Reporting in Use Case Driven Software Development

Iterative development is often the practice that most object oriented and component based projects adopt. It entails, however, dramatically increased managerial efforts due to seemingly never-ending user requirements that certainly add to complexity of project management. We emphasized the importance of progress, operationalized as a function of size and fault. Moreover, it is important that the progress be reported regularly and timely which necessitates collection of relevant data and more elaborated managerial process. We proposed progress estimation model and data model to automate data collection and efficient process for planning and change management on which project support systems were built and reported in this study. In the application of this newly designed management process and system to enterprise-wide projects, project risks appeared to be mitigated to a considerable extent with timely reporting of project progress. As a result, the resource planning and scheduling to control the change requirements was made available with ease. These practical managerial processes could make it possible to identify and resolve critical issues and risks at an early stage and eventually lead to high quality product.

Practical investigation into the maintainability of object-oriented systems for mission critical business

Empirical evidence on the maintainability of object-oriented systems is far from conclusive, partly due to lack of representativeness of the subjects and systems used in the study. This research empirically examined this issue for the systems that are mission-critical, currently operational and maintained by professionals. It was found that the OO group appeared to consume less time while maintaining more amount of software artifacts than the NOO counterpart. This economical utilization of time appeared evident regardless of software development life cycle. This was due to the usefulness of UML for impact analysis which contributed to effective comprehension and communication. Insufficient design specifications led to ambiguity and costly defects in transferring design solutions to development. Also the encapsulation of OO seemed to reduce mental loads at maintenance tasks and improved code reuse. However, the number of files to manage increased and thus, dependency management is required for the OO systems.