1. Digital Human Modeling
Vincent G. Duffy, Ph.D.
Associate Professor
Regenstrief Center for Healthcare Engineering
School of Industrial Engineering
and Department of Agricultural & Biological Engineering
Purdue University
Lecture 17 & 18
Thursday, March 29 & Tuesday April 3, 2007

2. Overview Defining DHM Brief Research Background
1st Generation DHM: Empirically Driven
Education & Original DHM Research
Advanced 1st Generation DHM: Verification & Validation
2nd Generation DHM: Computationally Driven
Moving Beyond Original Assumptions
3rd Generation DHM: Integrating the Cognitive Models
Opportunities for DHM Research
DHM in Healthcare Engineering
Bringing the DHM Research Community Together

3. Digital human models (DHM)
Defining DHM
Digital human models (DHM)
digital representation of the human inserted into a simulation or virtual environment to facilitate prediction of safety and/or performance
Includes a visualization and math/science in background
Enables engineers
to incorporate ergonomics and human factors engineering principles earlier in the design process (Duffy, 2004; Chaffin, 2005)
New concepts such as ‘Virtual Build’ using DHM
Eliminating need for prototyping
Facilitated by motion capture
See Brazier, et al. (2003), Li et al. (2004) at Applied Ergonomics, Wu et al. (2005) SAE-DHM
Providing real cost savings
$8.8 Million avoided in injury costs
Brazier, et al. (2003)

4. Perception-based safety design
Brief Research Background
Leading to DHM
Perception-based safety design applies fundamentals of human factors & ergonomics toward improved product and process design in various application domains including manufacturing, automotive, military and healthcare…
through evaluations of the impact of perception & decisions on safety
(Wickens, Lee, Liu & Gordon-Becker 2004)
(Computers in Industry, 2003,
Duffy, Wu & Ng)

5. Originating with Computer-Aided Ergonomics & Safety (CAES)
1st Generation DHM: Empirically Driven
Du, et al. (HAAMAHA 2005) used a NIOSH Lifting Equation, Static Strength Prediction - Postural Evaluation; Rapid upper limb assessment; Energy expenditure; Borg’s Rating of Perceived Exertion
Chaffin,1999; NIOSH,1994; McAtamney, 1993; De Luca, 1997; Marras, 1990;Garg 1978; Borg, 1982

6. Courses, Students Students, Projects
Education & Research
IE 590D Applied Ergonomics
30 students – many currently in industry registered through engineering professional education
IE 656 Digital Human Modeling: Research Seminar
- 12 Graduate & Undergraduate Students currently
IE 486 Work Analysis & Design II
80 students each semester

7. Virtual Interactive Safety Design
Advanced 1st Generation DHM: Verification & Validation
New
Real-time analysis; Motion capture; Virtual-view; Real wheelchair
(Ch.1-upper left) (Ch.2-upper right) (Ch.3-lower left) (Ch.4-lower right)
Old

8. Virtual Interactive Safety Design
Advanced 1st Generation DHM: Verification & Validation
New
Old

9. Dynamic Aspects of Work
Moving Beyond Original Assumptions
Classification of risk using motion capture (Cappelli & Duffy, 2005; 2006)
US Army-TACOM funded validation, dynamic aspects and cognitive model integration with Virtual Soldier Research (Mississippi State & U..Iowa)

10. 3rd Generation DHM: Integrating the Cognitive Models
Virtual prototypes: limitations & challenges in simulation & validation
3rd Generation DHM: Integrating the Cognitive Models
60/749,553 provisional patent application & SAE
(Duffy, et al. 2005).

11. Virtual prototypes: limitations & challenges in simulation & validation
Trade-offs in virtual & real prototyping
It was proposed that:
When product or process When product or process
requires more interactivity requires less interactivity
Full Prototype Full Simulation
Virtual environment for design iterations (Duffy, 2004)

12. DHM: Opportunities for Research
Origins: automotive, aerospace, military
Current capabilities: engineering science, math & computing
Needs: health systems, rehabilitation engineering
Current limitations: cross-disciplinary research
Needs driving emerging DHM
Identify foundations, fundamentals
Develop evaluation methods
analysis tools & applications
Engineering research:
increased by more than $1B in the past four years (ASEE, 2005)
DHM
Opportunities
Needs
Current Limitations
Capabilities

13. Opportunities for DHM: Computational Modeling & Visualization
Open loop vs. Closed loop
Closed loop- Device driven – eg. Biomedical Additional or Open effected by environment: human factors, HCI & ergonomics must be considered
Data abounds in the health care industry and inexpensive sensors make more data easily accessible
Better methods are needed to effectively apply engineering principles to healthcare delivery (open loop) in a systematic way
Application of traditional OR techniques may not be sufficient due to inherent non-linearities that make models with simplifying assumptions difficult to validate

14. Opportunities for DHM: Computational Modeling & Visualization
Open loop vs. Closed loop
Closed loop- Device driven – eg. Biomedical Additional or Open effected by environment: human factors, HCI & ergonomics must be considered
Data abounds in the health care industry and inexpensive sensors make more data easily accessible
Better methods are needed to effectively apply engineering principles to healthcare delivery (open loop) in a systematic way
Application of traditional OR techniques may not be sufficient due to inherent non-linearities that make models with simplifying assumptions difficult to validate
Computing infrastructure initiatives at the national level may bring additional support for applying more computing intensive models.
National attention has been brought to issues such as patient safety and the rising costs of healthcare that may encourage a willing partnership between engineering and the medical community for data gathering and model validation.

15. Simulations & Training for Nurses: RCHE On-campus Visit
DHM in Healthcare Engineering
DNP & Research Staff in the
Center for Nursing Education
Sim-Man -later to include Sim-Baby & Sim-Child using Health Fund Grant
- Lifelike heart and lung sounds, arterial waveforms, pulses, and responds physiologically to treatment.
- Can be programmed to cough, talk, moan, and respond to care while students monitor, analyze, and react.

16. Simulations & Prescriptive Medicine
DHM in Healthcare Engineering
There is a need for applying related computational modeling methods to prescriptive medicine, according to recommendations from the National Academies Institute of Medicine's forthcoming report that was recently presented to the Scientific Advisory Committee on Infant Mortality.

17. Simulations & Training for Surgeons
Toward Minimally Invasive Tele-robot/Augmented Simulation
Real Robotic Surgery Available - Laporoscopic
Intuitive’s DaVinci – need training alternatives & lower cost solutions

18. Bringing the DHM Research Community Together
Supplementing SAE-DHM efforts through
- ERCIM Digital Patient Working Group
- 1st ICDHM at HCII 2007
- Handbook of Digital Human Modeling
- 2nd AE 2008
- HFES HPM-TG
Including
Digital Visible Human
ICPT- Visualization, Perceptualization & Data Rendering

19. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Through DHM, various industries can bring occupational ergonomics earlier in design
For addressing, particularly the science of work
New DHM consider the changing nature of work
Examples of interest internationally (eg. Digital Visible Human)
Collaborating Centers and Academic Units at Purdue include:
IE, RCHE, ABE, AMC, PLM, NEXTRANS, SoS, ICPT, ME, AAE, CE, Health Sciences, Envision Center, Center for Aging, Center for Nursing Education.
with future applications especially in services industries such as: Healthcare, Energy, Logistics & Transportation Safety

20. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
1. A digital human model has which of the following: a. one part, and it is difficult to tell whether it is first, second or third generation b. two parts, including a visualization and some math and/or science in the background c. three parts, including a cognitive model d. my first Jack e. none of the above

21. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
1. A digital human model has which of the following: a. one part, and it is difficult to tell whether it is first, second or third generation b. two parts, including a visualization and some math and/or science in the background c. three parts, including a cognitive model d. my first Jack e. none of the above Answer: b

22. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
2. A cognitive model for DHM may be based on which of the following: a. Wickens Information Processing model b. A robot c. healthcare engineering d. all of the above e. none of the above

23. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
2. A cognitive model for DHM may be based on which of the following: a. Wickens Information Processing model b. A robot c. healthcare engineering d. all of the above e. none of the above
Answer: a

24. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
3. Second generation models are: a. empirically driven b. computationally driven c. always focused on verification and validation d. all of the above e. none of the above

25. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
3. Second generation models are: a. empirically driven b. computationally driven c. always focused on verification and validation d. all of the above e. none of the above
Answer: b

26. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
4. First generation DHM are: a. empirically driven b. more focused on validation and verification c. usually incorporate the physical aspects of work d. all of the above e. none of the above

27. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
4. First generation DHM are: a. empirically driven b. more focused on validation and verification c. usually incorporate the physical aspects of work d. all of the above e. none of the above
Answer: d

28. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
5. Jack software: a. enables analysis of computer generated workstations b. is available to Purdue students through all ITaP labs, and at home c. includes analyses related to RULA, NIOSH Lift, Comfort, Snook Tables, Postural Analysis & Energy Expenditure d. all of the above e. none of the above

29. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
5. Jack software: a. enables analysis of computer generated workstations b. is available to Purdue students through all ITaP labs, and at home c. includes analyses related to RULA, NIOSH Lift, Comfort, Snook Tables, Postural Analysis & Energy Expenditure d. all of the above e. none of the above
Answer: d

30. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
6. The human-system interface design for complex products can highlight a. current capabilities in cognitive models b. the need for more 1st generation models c. current limitations in DHM d. all of the above e. none of the above

31. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
6. The human-system interface design for complex products can highlight a. current capabilities in cognitive models b. the need for more 1st generation models c. current limitations in DHM d. all of the above e. none of the above
Answer: c

32. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
7. Motion capture systems enable: a. new models without old assumptions b. integration with CAE c. data related to Velocities, Accelerations, Angular Velocities and Angular Accelerations d. all of the above e. none of the above

33. Occupational Ergonomics Applications for DHM
In Summary
Occupational Ergonomics Applications for DHM
Review questions:
7. Motion capture systems enable: a. new models without old assumptions b. integration with CAE c. data related to Velocities, Accelerations, Angular Velocities & Angular Accelerations d. all of the above e. none of the above
Answer: d