scholarly journals The Onset Threshold of Cybersickness in Constant and Accelerating Optical Flow

2020 ◽  
Vol 10 (21) ◽  
pp. 7808
Author(s):  
Jiwon Kim ◽  
Taezoon Park
Keyword(s):  
Optical Flow ◽  
Constant Velocity ◽  
Human Subject ◽  
Rotational Axis ◽  
Constant Acceleration ◽  
Severe Nausea ◽  
Particle Field ◽  
Human Subject Experiment ◽  
Experimental Findings ◽  
Subject Experiment

This study investigated the principal translational or rotational axis that evokes the most severe cybersickness by detecting constant velocity and acceleration thresholds on the onset of cybersickness. This human subject experiment with 16 participants used a 3D particle field with movement directions (lateral, vertical, yaw, or pitch) and motion profiles (constant velocity or constant acceleration). The results showed that the threshold of pitch optical flow was suggestively lower than that of the yaw, and the vertical threshold was significantly lower than the lateral. Still, there was no effect of scene movement on the level of cybersickness. In four trials, the threshold increased from the first to the second trial, but the rest remained the same as the second one. However, the level of cybersickness increased significantly between the trials on the same day. The disorientation-related symptoms occurred on the first trial day diminished before the second trial day, but the oculomotor-related symptoms accumulated over the days. Although there were no correlations between the threshold and total cybersickness severity, participants with a lower threshold experienced severe nausea. The experimental findings can be applied in designing motion profiles to reduce cybersickness by controlling the optical flow in virtual reality.

scholarly journals Combining Head-Mounted and Projector-Based Displays for Surgical Training

2004 ◽  
Vol 13 (2) ◽  
pp. 128-145 ◽  
Author(s):  
Adrian Ilie ◽  
Kok-Lim Low ◽  
Greg Welch ◽  
Anselmo Lastra ◽  
Henry Fuchs ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Surgical Training ◽  
Human Subject ◽  
Visual Awareness ◽  
Display System ◽  
Geometric Calibration ◽  
Calibration Process ◽  
Surrounding Environment ◽  
Human Subject Experiment ◽  
Subject Experiment

We introduce and present preliminary results for a hybrid display system combining head-mounted and projector-based displays. Our work is motivated by a surgical training application where it is necessary to simultaneously provide both a highfidelity view of a central close-up task (the surgery) and visual awareness of objects and events in the surrounding environment. In this article, we motivate the use of a hybrid display system, discuss previous work, describe a prototype along with methods for geometric calibration, and present results from a controlled human subject experiment. This article is an invited resubmission of work presented at IEEE Virtual Reality 2003. The article has been updated and expanded to include (among other things) additional related work and more details about the calibration process.

Dimensions of Similarity Used to Identify Products As Sources of Analogy

2020 ◽  
Author(s):  
Arnold N. Tsoka ◽  
Jicmat Ali Tribaldos ◽  
Chiradeep Sen
Keyword(s):  
Human Subject ◽  
Human Interaction ◽  
Target Product ◽  
Material Flows ◽  
Design Task ◽  
Energy Flows ◽  
Working Principle ◽  
Human Subject Experiment ◽  
Subject Experiment ◽  
Total Dimension

Abstract This paper presents a human-subject experiment exploring the dimensions of product similarity that designers use to detect a product as a source of analogy during designing another. In the study, fifty voluntary participants are presented with a target product that is to be designed, and five other source products that are similar to the design task in various dimensions such as function, structure, or working principle. The designers are then asked to identify the products that they consider to be useful sources of analogy for designing the target, and to write in plain English why they considered so. These comments are analyzed using a protocol to reveal the dimensions of similarity between the target and the source product that inspired them to select the source. The data comprises of 2,440 total dimension instances among the participants. The results show that the identification of products as sources of analogy is driven by at least six dimensions: working principle, structure, human interaction, function, energy flows, and material flows. Among these, working principle, structure, and human interaction are more dominant than function, which was previously believed to be the sole driver of analogy.

Coordinated Rate Control of a Hydraulic Excavator Using Traditional Joystick Hardware

2015 ◽  
Author(s):  
Samuel F. Seifert ◽  
Wayne J. Book
Keyword(s):  
Rate Control ◽  
Human Subject ◽  
Performance Metrics ◽  
Coordinated Control ◽  
Self Report ◽  
End Effector ◽  
Performance Improvements ◽  
Hydraulic Excavators ◽  
Human Subject Experiment ◽  
Subject Experiment

This paper presents a novel user interface (UI) for coordinated rate control (CRC) of an excavator end effector using traditional hardware. Coordinated control of an excavator end effector alleviates the cognitive load created by nonlinear arm dynamics on the excavator operator, allowing the operator to perform tasks more quickly and with fewer errors. A human subject experiment demonstrates the feasibility of excavator CRC using the traditional twin joystick setup, and compares operator performance between a CRC UI and traditional excavator UI. Performance of the CRC UI was statically equivalent to the performance of the traditional UI. When asked to self-report UI preference: 26 participants stated they preferred the CRC UI, 6 preferred the traditional UI, and 14 had no preference. Although the current iteration of the CRC UI offered no measurable performance improvements, a remapping of the CRC joystick inputs to the end effector motion could make the CRC UI more intuitive, lead to better performance metrics, and make hydraulic excavators safer, more efficient, and easier to use.

IMM-UKF-TFS Model-based Approach for Intelligent Navigation

2013 ◽  
Vol 66 (6) ◽  
pp. 859-877 ◽  
Author(s):  
M. Malleswaran ◽  
V. Vaidehi ◽  
S. Irwin ◽  
B. Robin
Keyword(s):  
Kalman Filter ◽  
Constant Velocity ◽  
Unscented Kalman Filter ◽  
Interacting Multiple Model ◽  
Multiple Model ◽  
State Variables ◽  
Constant Acceleration ◽  
Positional Accuracy ◽  
Model Based ◽  
Novel Approach

This paper aims to introduce a novel approach named IMM-UKF-TFS (Interacting Multiple Model-Unscented Kalman Filter-Two Filter Smoother) to attain positional accuracy in the intelligent navigation of a manoeuvring vehicle. Here, the navigation filter is designed with an Unscented Kalman Filter (UKF), together with an Interacting Multiple Model algorithm (IMM), which estimates the state variables and handles the noise uncertainty of the manoeuvring vehicle. A model-based estimator named Two Filter Smoothing (TFS) is implemented along with the UKF-based IMM to improve positional accuracy. The performance of the proposed IMM-UKF-TFS method is verified by modelling the vehicle motion into Constant Velocity-Coordinated Turn (CV-CT), Constant Velocity – Constant Acceleration (CV-CA) and Constant Acceleration-Coordinated Turn (CA-CT) models. The simulation results proved that the proposed IMM-UKF-TFS gives better positional accuracy than the existing conventional estimators such as UKF and IMM-UKF.

On the Discussion of the Damping Reduction Factors in the Constant Acceleration Region for ATC-40 and FEMA-273

2003 ◽  
Vol 19 (4) ◽  
pp. 1001-1006 ◽  
Author(s):  
Yu-Yuan Lin ◽  
Meng-Hao Tsai ◽  
Kuo-Chun Chang
Keyword(s):  
Constant Velocity ◽  
Response Spectra ◽  
Design Practice ◽  
Velocity Range ◽  
Acceleration Region ◽  
Constant Acceleration ◽  
Reduction Factors

According to the ATC-40 (1996) and FEMA-273 (1997) documents, the damping reduction factors for the constant acceleration range of the design response spectra are larger than those for the constant velocity range of those. This trend is contrary to the results obtained from several recent studies and may lead to underestimates of the high-damped design response spectra. This paper points out the issue and suggests further examinations of the factor in the constant acceleration region with potential revision to design practice.

Development of the Variable-Rate Transymmetric Motion With Discretely Vanishing Shock

1984 ◽  
Vol 106 (1) ◽  
pp. 109-113 ◽  
Author(s):  
S. N. Kramer
Keyword(s):  
Constant Velocity ◽  
Angular Displacement ◽  
Operating Cost ◽  
Dynamic Responses ◽  
Variable Rate ◽  
Constant Acceleration ◽  
Functional Relationships ◽  
Rest Position ◽  
New Type ◽  
Velocity Motion

In industry when a link, crank, or other mechanical component is to be rotated from one rest position to another, it is necessary to establish appropriate functional relationships for angular displacement, velocity, and acceleration versus time such that the output motion satisfies certain kinematic and dynamic requirements. In the work presented here, a new type of motion is developed which has distinct advantages over constant velocity motion, constant acceleration motion, simple harmonic motion, cycloidal motion, and polynomial motions. The “variable-rate transymmetric” motion allows a designer to assign specific portions of the motion to be described by a linearly varying acceleration and other portions by a constant acceleration. As a result, the designer can decrease the power required, decrease the operating cost, and decrease dynamic responses such as shock, vibration, and shaking force.

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