Enhancing the capabilities of the dismounted combatant has been an enduring goal of international military research communities. Emerging developments in exoskeleton technology offers the potential to augment the dismounted combatant's capabilities. However, the ability to determine the value proposition of an exoskeleton in a military context is difficult due to the variety of methods and metrics used to evaluate previous devices. The aim of this paper was to present a standard framework for the evaluation and assessment of exoskeletons for use in the military. A structured and systematic methodology was developed from the end-user perspective and progresses from controlled laboratory conditions (Stage A), to simulated movements specific to the dismounted combatant (Stage B), and real-world military specific tasks (Stage C). A standard set of objective and subjective metrics were described to ensure a holistic assessment on the human response to wearing the exoskeleton and the device's mechanical performance during each stage. A standardised methodology will ensure further advancement of exoskeleton technology and support improved international collaboration across research and industry groups. In doing so, this better enables international military groups to evaluate a system's potential, with the hope of accelerating the maturity and ultimately the fielding of devices to augment the dismounted close combatant and small team capability.

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Drinking behavior in Birgus latro and Gecarcoidea lalandii was videotaped under controlled laboratory conditions. B. latro displayed the drinking behavior typically observed in nature, spooning up water with the chelae (Lister, 1888; Gross, 1955). G. lalandii is documented for the first time displaying this same behavior; however it obtained water primarily through immersion. Under normal hydrated conditions (hemolymph osmolarities < 1050 mOsm) B. latro showed no preference for drinking fresh or seawater. When dehydrated (hemolymph osmolarities > 1050 mOsm) B. latro altered its drinking behavior and showed a distinct preference for freshwater. This strategy resulted in restoration of original hemolymph osmolarities and wet weights and was accomplished through periods of intensive drinking activity. Conversely, G. lalandii never experienced true dehydration; rather, the hemolymph became hyperosmotic compared with control animals. This species preferred freshwater both under normal and hemoconcentrated conditions. G. lalandii was also able to osmoregulate behaviorally and was able to restore hemolymph osmolarities to normal concentrations via immersion in freshwater following experimentally induced hemoconcentration. Possible physiological and ecological reasons for the differences in water uptake strategies and preferences are discussed.

Approved for public release; distribution is unlimited.ii REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.A novel mobility platform, the Omni-Directional Treadmill (ODT) Upgrade, has been developed to allow users to move through a virtual environment in a manner equivalent to doing so in the real world. The purpose of this investigation was to determine the extent to which walking on the ODT Upgrade is comparable to walking overground for selected biomechanical and physiological variables. Temporal-spatial parameters, sagittal plane joint kinematics, and metabolic cost were assessed for 10 subjects as they walked along identical circular courses overground and on the ODT Upgrade. Except for a reduction in ankle plantarflexion following toe-off on the ODT Upgrade, differences in gait mechanics between the overground and ODT Upgrade trials were relatively small. However, oxygen consumption was more than 20% greater during walking on the ODT Upgrade than overground, and must be taken into account when comparing the results of training and research conducted on the ODT Upgrade to that of the real world. Future studies are required to develop a better understanding of the potential mechanisms behind this substantial increase in metabolic cost. In conclusion, the ODT Upgrade permits users to walk through a virtual environment in a relatively natural way but with a significant increase in physiological demand. 15. SUBJECT TERMS omni-directional treadmill, gait, metabolic cost, immersive simulation, mobility interface 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 38 19a. NAME OF RESPONSIBLE PERSON Unclassified b. ABSTRACT Unclassified c. THIS PAGE Unclassified 19b. TELEPHONE NUMBER (Include area code) 410-278-3621 Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18

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