John McGinley

Wavelets applied to loseless compression and progressive transmission of floating point data in 3-D curvilinear grids

A method of lossless compression using wavelets is presented that enables progressive transmission of computational fluid dynamics (CFD) data in PLOT3D format. The floating point data is first converted to double-precision floating point format to maintain adequate precision throughout the transform process. It is then transformed using Haar wavelets-four times in two spatial dimensions, twice in the third spatial dimension, and twice in time for a total compression factor of 64 times. The double precision format will maintain enough precision during the transform to keep the process lossless. Next, the transformed data is compressed using Huffman coding and transmitted progressively using spectral selection. This allows most of the information to be transmitted in the first pass. Details are transmitted in later passes which ultimately provide for lossless reconstruction of the original data.

Productivity simulation with promodel for an automotive assembly workstation involving a lift assist device

With advances in computer technology and digital human modeling methodology, it is possible to predict risks of potential injuries during manufacturing design prior to production, and make proactive ergonomic design for manufacturing assembly workstations involving human-machine interfaces. However, the productivity of manufacturing systems may be decreased, and this negative impact is difficult to evaluate in experimental and manufacturing environments. This research focuses on productivity issue for an automotive assembly workstation involving a lift assist device. To evaluate the productivity of the assembly workstation interfered by proactive ergonomic design, a prescriptive model of the automotive assembly system is developed and simulated with ProModel. This model and its simulation can not only evaluate the productivity, but also determine the maximum conveyor speed. Furthermore, this methodology using ProModel simulation to evaluate productivity and utilization described in this paper can be extended to evaluating other human-machine systems with dynamic, stochastic, and discrete-event characteristics

Effecting validity of ergonomics analysis during virtual interactive design

This paper focuses on validating the performance of virtual interactive design (VID) environment with dynamic ergonomics analysis. Previous studies have only validated VID for posture-based static ergonomics analysis, and applied the methodology on several studies. While since dynamic information is important for ergonomics analysis, this study will investigate the performance of VID environment for ergonomics analysis considering dynamic information such as velocity, which uses motion instead of posture as analysis target.

Pedestrian Perception of Autonomous Vehicles with External Interacting Features

The increasing number of autonomous vehicles has raised questions regarding pedestrian interaction with autonomous vehicles. Researchers have studied external interfaces designed for vehicle operators and other road-users (e.g., pedestrians). Most past studies have considered the interaction between pedestrians and autonomous vehicles with no visible operator. However, pedestrian-autonomous vehicle interaction may be complicated when there is a human sitting in the conventional driver’s seat of an autonomous vehicle. Such a scenario may cause some pedestrians to look to the passenger for cues when they should be looking for cues from the vehicle. The objective of the current study was to investigate pedestrians’ perspective of autonomous vehicles based on the interaction effect between passenger status and external features on the vehicle. Sixteen pedestrians completed a VR experiment. The results provided important insight into the important question of pedestrian-autonomous vehicle interaction when passengers are present in the driver seat of the vehicle.

Conducting a Prospective Review for Enhanced Interface Features for Unmanned Ground Vehicle Operation

When developing new interface features, it is vital to consider the perspectives of users from several backgrounds throughout the process, in order to ensure features that address realistic user concerns in effective ways. The Systematic Human Error Reduction and Prediction Approach (SHERPA) and an established user acceptance questionnaire were used to evaluate the predicted usability and acceptability of four enhanced interface features for unmanned ground vehicle (UGV) operation. The targeted interface is designed for use in real-world and simulated environments. Although the SHERPA results alone did not clearly distinguish between interface enhancements, the user acceptance results from team members converged on a single ‘best’ interface enhancement for supporting collision avoidance and navigation, based on assessments using early mock-ups in a simulated environment.

Musculoskeletal and performance effects of monocular display augmented, articulated arm based laser digitizing

Processes of capturing solid geometry features as three-dimensional data for analysis, simulation, or reverse engineering require the use of laser-based reverse engineering hardware, commonly known as digitizers. The most common digitizers used within manufacturing contexts are articulated arm-based coordinate measuring machines, which have been augmented with a laser-head probe. Typical usage times for the digitizing equipment can range into the hours, thereby placing operators at risk for the development of musculoskeletal disorders (MSDs), though exact load magnitudes of exposure to risk factors for MSDs during object digitization are unknown. Further, other technologies (such as monocular/heads-up displays) may be combined with laser digitizers that may reduce load magnitudes. This paper explores the possibility of an occluded monocular display augmentation, results and discussion are presented.

Modeling human bipedal navigation in a dynamic three dimensional virtual environment

The current research sought to construct a computational model of human navigation for virtual three dimensional environments. The model was implemented within the ACT-R cognitive architecture [1]. The navigation model incorporates visual search, encoding object features and spatial relationships, motion, obstacle avoidance, and incidental visual memory.

Cross-Validation of an Infrared Motion Capture System and an Electromechanical Motion Capture Device

The current research conducted a cross-validation between an infrared motion capture system and an electromechanical motion capture device. No differences were found between the motion capture methods in shoulder and elbow angles. However, differences were found between the motion capture methods on distances of hand movements and actor location in space. Results of the current study indicate electromechanical motion capture devices are too inaccurate to use for validating digital human models unless the ultimate application of the model does not require millimeter accuracy or an absolute location in space. If one is primarily interested in joint angles, and distances are secondary, an electromechanical device is acceptable.