International Journal of Human Factors Modelling and Simulation (6 papers in press)
Predictive simulation of human circular gait
by Yujiang Xiang, Paul Owens
Abstract: This paper presents a one-stride formulation to simulate human circular gait using a skeletal model. The formulation is based on a previously presented asymmetric walking formulation (Xiang et al. 2011). The circular walking motion is analyzed using the proposed motion prediction method. The global moments due to active forces are decomposed at pelvis to retrieve correct zero moment point (ZMP) and ground reaction forces (GRF). The predicted GRF are compared to those of straight walk. Some insights on human circular gait are obtained. It is found that the transverse GRF of outer step is much larger than that of inner step for a circular gait, and the turning motion has larger jerk for the ZMP trajectory compared to the straight walk, i.e., it has more potential to fall. In addition, the straight walking is validated with the experimental data, and the peak knee joint angle values of the circular gait are compared with the data in the literature.
Keywords: Circular gait; Jerk; Turning; Fall; Optimization.
Projection of Anthropometric Correlation for Virtual Population Modelling
by John Rasmussen, Rasmus Plenge Waagepetersen, Kasper Pihl Rasmussen
Abstract: A new statistical method for generation of virtual populations based on anthropometric parameters is developed. The method addresses the problem that most anthropometric information is reported in terms of summary data such as means and standard deviations only, while the underlying raw data, and therefore the correlations between parameters, are not accessible. This problem is solved by projecting correlation from a data set for which raw data are provided.rnThe method is tested and validated by generation of pseudo females from males in the ANSUR anthropometric dataset. Results show that the statistical congruency of the pseudo population with an actual female population is more than 90\% for more than 90\% of the possible parameter pairs. The method represents a new opportunity to generate virtual populations for specific geographic regions and ethnicities based on summary data only.
Keywords: Anthropometry; Human factors; Statistics; Principal component analysis; PCA; Correlation.
Ergonomic Risk Assessment in DHM tools Employing Motion Data Exposure Calculation and Comparison to Epidemiological Reference Data
by Ida-Märta Rhén, Mikael Forsman, Roland Örtengren, Dan Högberg, Ali Keyvani, Dan Lämkull, Lars Hanson
Abstract: Digital human modelling (DHM) allows ergonomic risk assessment to be performed at early stages of design and development. Such assessment is typically based on observational methods, which do not take advantage of the potential of DHM tools to provide precise posture and motion data. This paper describes and illustrates an alternative assessment approach employing DHM tools, inspired by risk assessment based on direct measurements. A literature survey established a reference database of epidemiological associations between exposure and wrist-related disorders. This approach is illustrated by a DHM simulation of a car assembly task. Wrist posture and motion were simulated and compared to the database, predicting the prevalence of work-related musculoskeletal disorders on the basis of direct measurements.
Keywords: biomechanical load; digital human modelling; wrist; repetitive strain injuries; direct measurements; exposure-response relationship; work-related musculoskeletal disorders; physical workload.
Driver Response to Steering Perturbations: Mechanical Arm Admittance and Grip Pressure
by Antonin Joly, Rencheng Zheng, Kimihiko Nakano
Abstract: The monitoring of the driver condition has been studied extensively to develop advanced driver assistance systems aimed at reducing the driving burden. Whereas, the available methods for acquiring information about the condition of the driver are limited to the analysis of driving performances and the monitoring of the visual behaviour via cameras. The lack of approaches for monitoring the condition of driver is caused by the nature of the sensor, as nonintrusive methods are largely preferred when designing an assistance system. In this study, we propose to estimate the condition of the drivers via the relationship between mechanical arm admittance, which provides the dynamics of the arm through a relation between a force input and a position output, and grip pressure of the drivers in the frequency range of [0.1 0.5 Hz]. The effects of perturbation amplitude and between subject variations were investigated. A total of ten participants performed driving simulations to determine these characteristics. Participants were instructed to firmly grab the steering wheel in a ten-to-two position while wearing grip sensors gloves. Experimental results show that mechanical arm admittance is a power function of the grip pressure of the participants. A non-linear response was obtained with larger admittance with larger perturbation amplitudes.
Keywords: human factors; driver monitoring; mechanical arm admittance; grip pressure.
Special Issue on: Quantifying Human Factors Towards Analytical Human-in-the-Loop
Relevance of Air-Traffic Controllers Tacit Knowledge in Enhancing Air-Traffic Control and Safety in Ghanaian Airspace
by Mohammed-Aminu Sanda
Abstract: This study explored the cognitive and workload demands of air-traffic control activity and the tacit knowledge used by air-traffic controllers to cope with the stress associated with such demands in ensuring air-traffic safety in Ghana. Guided by the systemic structural theory of activity, it was found that the air-traffic control activity entailed several challenges, whereby variety of tasks demand significant cognitive efforts, requiring use of tacit knowledge by the air-traffic controllers to augment their operational performances in order to enhance air-traffic safety. It is concluded that the functional efficiency and effectiveness of human work in the air-traffic control activity can be enhanced by understanding and integrating air-traffic controllers tacit knowledge in the job design. By implication, this understanding can be incorporated in designing an operator-efficient and effective work system for air-traffic controllers in order enhance their management capacity of air-traffic safety in Ghana.
Keywords: Air-traffic control activity; Air-traffic controller; Tacit knowledge; Air-traffic safety; Ghana.
Bayesian Network for the Prediction of Situation Awareness Errors
by Jean-Marc Salotti
Abstract: A new method is proposed to predict situation awareness errors in training simulations. It is based on Endsleys model and the 8 situation awareness demons that she described. The predictions are determined thanks to a Bayesian network and Noisy-Or nodes. A maturity model is introduced to come up with the initialization problem. The NASA behavioural competency model is also used to take individual differences into account.
Keywords: Situation awareness; Bayesian network; noisy-or; behavioural competency.