Aida Erfanian

Force and vibrotactile integration for 3D user interaction within virtual environments

Proper integration of sensory cues facilitates 3D user interaction within virtual environments (VEs). Studies on multi-sensory integration of visual and haptic cues revealed that the integration follows maximum likelihood estimation (MLE). Little effort focuses however on integrating force and vibrotactile cues - two sub-categorical cues of the haptic modality. Hence, this paper presents an investigation on MLEs suitability for integrating these sub-categorical cues. Within a stereoscopic VE, human users performed a 3D interactive task of navigating a flying drone along a high-voltage transmission line in an inaccessible region and identifying defects on the line. The users had to identify defects via individual force or vibrotactile cues, and their combinations in co-located and dislocated settings. The co-located setting provided both cues on the right hand of the users; whereas the dislocated setting delivered the force and vibrotactile cues on the right hand and forearm of the users, respectively. Task performance of the users, such as completion time and accuracy, was assessed under each cue and setting. The presence of the vibrotactile cue promoted a better performance than the force cue alone. This was in agreement with the role of tactile cues in sensing surface properties, herein setting a baseline for using MLE. The task performance under the co-located setting indicated certain degrees of combining those under the individual cues. In contrast, the performance under the dislocated setting was alike that under the individual vibrotactile cue. These observations imply an inconclusiveness of MLE to integrate both cues in a co-located setting for 3D user interaction.

Navigation in virtual environments: Design and comparison of two anklet vibration patterns for guidance

In this study, we present a preliminary exploration about the added value of vibration information for guiding navigation in a VE. The exploration consists of two parts. Firstly, we designed two different vibration patterns. These patterns, pushing pattern and compass pattern, differ conceptually in the levels of abstraction. Secondly, we undertook an experiment to compare the two patterns in guiding navigation in a VE. The objective of the comparison is to establish a baseline for examining the suitability of using vibration patterns to guide navigation.

Multi-user efficacy of collaborative virtual environments

Multi-user efficacy is a key factor of genuine collaboration among multiple users towards a common goal. To assess multi-user efficacy, social scientists have traditionally applied subjective measurements from a theoretical perspective. Researchers in human-computer interaction have developed combined metrics of objective and subjective measurements. Nevertheless, the combined metrics fall short to fully cover the theoretical perspective of social scientists. To remedy this shortfall, we have developed a set of objective and subjective metrics to complete the theoretical perspective. Utilizing the metrics, we present in this paper a study to verify the robustness of our dynamic priority (DP) model, which under a quasi-practical scenario resolves command conflicts and promotes perceived equality in interaction among multiple users. In the study, we utilized a realistic scenario which differs from the quasi-practical scenario in the allowance of verbal communication among users. The results of the study revealed that the DP model yielded a significantly higher degree of multi-user efficacy under the realistic scenario than the quasi-practical scenario. Moreover, there was no significant difference of the perceived equality in interaction between both scenarios. These observations confirm the robustness of the DP model, and imply the potential application of the model for genuine collaboration within multi-user VEs.

Conflict resolution models on usefulness within multi-user collaborative virtual environments

Conflict resolution models play key roles in coordinating simultaneous interactions in multi-user collaborative virtual environments (VEs). Currently, conflict resolution models are first-come-first-serve (FCFS) and dynamic priority (DP). Known to be unfair, the FCFS model grants all interaction opportunities to the agilest user. Instead, the DP model permits all users the perception of equality in interaction. Nevertheless, it remains unclear whether the perception of equality in interaction could impact the usefulness of multi-user collaborative VEs. Thus, this present work compared the FCFS and DP models for underlying the usefulness of multi-user collaborative VEs. This comparison was undertaken based on a metrics of usefulness (i.e., task focus, decision time, and consensus), which we defined according to the ISO/IEC 205010:2011 standard. This definition remedied the current metrics of usefulness that measures actually effectiveness and efficiency of target technologies, instead of their usefulness. On our multi-user collaborative VE, we observed that the DP model yielded significantly lower decision time and higher consensus than the FCFS model. There was, however, no significant difference of task focus between both models. These observations imply a potential to improve multi-user collaborative VEs.

Framework of Multiuser Satisfaction for Assessing Interaction Models Within Collaborative Virtual Environments

Collaborative virtual environments (VEs) require interaction models for resolving conflicts and promoting multiuser collaboration. Common models, such as the first-come-first-serve (FCFS) model, which grants interaction opportunities to the most agile user, and the static priority model, which gives interaction opportunities to the user with the highest predefined priority, disregard the importance of perceiving equality in interaction (EII) among all users. One exception is the dynamic priority (DP) model, as proposed in our earlier work, which grants interaction opportunities to a user based on the recency of his/her gained opportunities. To date, few research efforts have investigated the effect of interaction models on multiuser satisfaction. This paper hence presents an assessment of the DP models effect on multiuser satisfaction within a collaborative VE. We first verified that the DP model allowed multiple users to perceive EII. We then conducted an experiment to examine the effect of the DP and FCFS models on multiuser satisfaction under a quasi-practical scenario that mimicked a decision-making meeting of experts. The framework of the examination was based on several metrics, which we proposed for the components of the ISO/IEC 25010:2011 standard. This framework resolved issues with existing metrics that measure user satisfaction by analyzing individual experience, thus omitting EII desired by multiple users. The results of the experiment indicated that the DP model fulfilled the metrics of the framework significantly better than the FCFS model. This observation implies a potential application of the DP model in collaborative VEs where multiuser satisfaction is the key to productive collaboration.

Defining an Indicator for Navigation Performance Measurement in VE Based on ISO/IEC15939

Navigation is a key factor for immersion and exploration in virtual environment (VE). Nevertheless, measuring navigation performance is not an easy task, especially when analyzing and interpreting heterogeneous results of the measures used. To that end, we propose, in this paper, a new indicator for measuring navigation performance in VE based on ISO/IEC 15939 standard. It allows effective integration of heterogeneous results by retaining its raw values. Also, it provides a new method that offers a comprehensive graphical visualization of the data for interpreting the results. The experimental study had shown the feasibility of this indicator and its contribution to statistical results.