Performance of human operators under various system parameters
Application of human operator performance for varied parameters to design of man-machine system
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Application of human operator performance for varied parameters to design of man-machine system
Many structural failures have occasionally been attributed to human factors in engineering design, analyses maintenance, and fabrication processes. Every facet of the engineering process is heavily governed by human factors and the degree of uncertainty associated with them. Factors such as societal, physical, professional, psychological, and many others introduce uncertainties that significantly influence the reliability of human performance. Quantifying human factors and associated uncertainties in structural reliability require: (1) identification of the fundamental factors that influence human performance, and (2) models to describe the interaction of these factors. An approach is being developed to quantify the uncertainties associated with the human performance. This approach consists of a multi factor model in conjunction with direct Monte-Carlo simulation.
Human tracking performance under transverse acceleration
"Cognition in Space Workshop I: Metrics and Models" was the first in a series of workshops sponsored by NASA to develop an integrated research and development plan supporting human cognition in space exploration. The workshop was held in Chandler, Arizona, October 25-27, 2004. The participants represented academia, government agencies, and medical centers. This workshop addressed the following goal of the NASA Human System Integration Program for Exploration: to develop a program to manage risks due to human performance and human error, specifically ones tied to cognition. Risks range from catastrophic error to degradation of efficiency and failure to accomplish mission goals. Cognition itself includes memory, decision making, initiation of motor responses, sensation, and perception. Four subgoals were also defined at the workshop as follows: (1) NASA needs to develop a human-centered design process that incorporates standards for human cognition, human performance, and assessment of human interfaces; (2) NASA needs to identify and assess factors that increase risks associated with cognition; (3) NASA needs to predict risks associated with cognition; and (4) NASA needs to mitigate risk, both prior to actual missions and in real time. This report develops the material relating to these four subgoals.
Human tracking performance & tolerance to acceleration
Human performance and eye movements of operator performing compensatory tracking with coordinated multiple inputs
Human space exploration is inherently hazardous, particularly for lon g duration (LD) missions (22 days or longer). Maintenance of cognitive functioning is essential, but flight environments pose numerous pote ntial risks to the brain and cognitive performance (eg, radiation, to xins, chronic stress, sleep deprivation, hypercarbia, fluid shifts, h ormone imbalances, and injury). There have been persistent anecdotal reports of cognitive deficits during missions, but an up?-to-date rev iew of the evidence for such changes has remained unavailable. Method s: We identified and reviewed English language publications found via electronic searches in PubMed, PsycInfo, Inspec, the NASA Technical Report Server, and the Defense Technical Information Center, plus rec ursive searches of publication bibliographies. Search terms included the word cognition, cognitive, or performance along with spaceflight, flight, mission, or closely related terms. Results: Inter?-study variability precluded meta?-analysis. Some 32 published studies involving cognitive assessment during spaceflight were identified, involving a total of 110 participants (mean: 3.4 participants per study). The lo ngest?-duration study spanned 438 days, with six additional studies i nvolving flight durations of 90 days, and 11 more studies involved fl ight durations exceeding 21 days. The available evidence failed to st rongly support or refute the existence of cognitive deficits in LD sp aceflight, in part due to inadequate power or control conditions. Evi dence of increased variability in cognitive performance during spacef light, both within and between individuals, was common. Discussion: T hese results represent a negative finding based on small numbers of s ubjects for any given cognitive function. The increased variability within and (particularly) between individuals highlights the potential danger of generalizing from case studies. A mismatch therefore remain s between anecdotal reports describing generalized cognitive slowing, attention and memory problems during missions and the experimental e vidence supporting such deficits. Since a major justification for man ned spaceflight rests with the cognitive flexibility of humans, addit ional studies and further analysis of existing operational data appea rs warranted.
Human capabilities such as dexterity, manipulability, and tactile perception are unique and render the hands as a very versatile, effective and a multipurpose tool. This is especially true for environments such as the EVA environment. However, with the use of the protective EVA gloves, there is much evidence to suggest that human performance decreases. In order to determine the nature and cause of this performance decrement, several performance tests were run which studied the effects of gloves on strength, tactile feedback, and range of motion. Tactile sensitivity was measured as a function of grip strength, and the results are discussed. Equipment which was developed to measure finger range of motion along with corresponding finger strength values is discussed. The results of these studies have useful implications for improved glove design.
This report presents tile results of an experimental and analytical study of human performance in uncoupled and coupled control systems. Human pilot performance in single and two-axis systems was mathematically modeled by linear second-order describing functions. Model parameters were determined using model matching techniques. Analysis of the models showed that the amplitude ratio and phase lead of the describing function increased with training indicating an increase in open loop bandwidth. The phase margin also decreased with training. Increasing the plant lag time constant resulted in an increase in the model lead time constant and a decrease in the zero frequency gain. No significant difference was found to exist in the normalized tracking error per axis between the two-axis tasks and the single-axis tasks. However tile model lead time constant was significantly greater in two-axis tracking. Manual tracking of two-axis systems with cross-coupling was studied experimentally and analytically. Approximate methods for modeling two-axis performance were developed and checked using a precise spectral analysis approach. Coupled and uncoupled, symmetrical and asymmetrical two-axis performance was compared. The results show that modeling of cross-coupled systems is feasible and that trained subjects are capable of decoupling the axes of some systems. A methodology study compared the identification performance of continuous, iterative, and extrapolation model matching techniques. An iterative technique employing sensitivity equations for the generation of influence coefficients was found to be the best technique due to its excellent identification accuracy and ease of implementation. Convergence in iterative techniques can be improved substantially by equalizing the parameter adjustment rates and limiting the maximum correction per iteration.
Usefulness of transinformation as measure of human tracking performance
Aspects of human operator performance in low order compensatory control tasks studied with regression analysis
Abstract not provided.
Abstract not provided.
Human pilot tracking performance in uncoupled and coupled two-axis control systems
Lack of appropriate human performance data for the development of human reliability analysis (HRA) methods has been identified as a key issue contributing to the method-to-method variability among the HRA methods. The United States Nuclear Regulatory Commission (NRC) worked with domain experts to develop the Scenario Authoring, Characterization, and Debriefing Application (SACADA) system to collect nuclear power plants' licensed operator simulator training and examination data to inform HRA. In the past two decades, significant improvements in understanding and modelling human performance in HRA have affected the perspectives of the types of data to be collected for HRA. A significant change is that human performance is strongly dependent on the context of the tasks to be performed. To incorporate this understanding, the SACADA data taxonomy collects the context and actual performance information of the training objective elements (TOEs) in nuclear plant operator simulator training. This provides a framework consistent with HRA to use context to estimate human error probabilities. It is recognized that measuring crew performance is equally important as improving operator training. SACADA is designed to support the nuclear trainers in capturing this important information that is used to identify training weaknesses and drive continuous improvement. This paper discusses the SACADA taxonomy, the SACADA system's functions, and the supporting software design to enable the SACADA system to be practically implemented in the nuclear power plants' operator simulator training program to collect data for tracking operator performance and HRA analysis. (authors)
The vision of the technology and development teams at NASA Ames and Johnson Research Centers is to provide the capability for automated delivery and emplacement of habitats and surface facilities. The benefits of the program are as follows: Composites and Inflatables: 30-50% (goal) lighter than Al Hard Structures; Capability for Increased Habitable Volume, Launch Efficiency; Long Term Growth Potential; and Supports initiation of commercial and industrial expansion. Key Habitats and Surface Construction (H&SC) technology issues are: Habitat Shell Structural Materials; Seals and Mechanisms; Construction and Assembly: Automated Pro-Deploy Construction Systems; ISRU Soil/Construction Equipment: Lightweight and Lower Power Needs; Radiation Protection (Health and Human Performance Tech.); Life Support System (Regenerative Life Support System Tech.); Human Physiology of Long Duration Space Flight (Health and Human Performance Tech.); and Human Psychology of Long Duration Space Flight (Health and Human Performance Tech.) What is being done regarding these issues?: Use of composite materials for X-38 CRV, RLV, etc.; TransHAB inflatable habitat design/development; Japanese corporations working on ISRU-derived construction processes. What needs to be done for the 2004 Go Decision?: Characterize Mars Environmental Conditions: Civil Engineering, Material Durability, etc.; Determine Credibility of Inflatable Structures for Human Habitation; and Determine Seal Technology for Mechanisms and Hatches, Life Cycle, and Durability. An overview encompassing all of the issues above is presented.
With recent announcements of the development of permanently staffed facilities on the Moon and Mars, the national space plan is in need of an infrastructure system for transportation and maintenance. A project team at the University of Houston College of Architecture and the Sasakawa International Center for Space Architecture, recently examined components for a low Earth orbit (LEO) transportation node that supports a lunar build-up scenario. Areas of investigation included identifying transportation node functions, identifying existing space systems and subsystems, analyzing variable orbits, determining logistics strategies for maintenance, and investigating assured crew return systems. The information resulted in a requirements definition document, from which the team then addressed conceptual designs for a LEO transportation node. The primary design drivers included: orbital stability, maximizing human performance and safety, vehicle maintainability, and modularity within existing space infrastructure. For orbital stability, the power tower configuration provides a gravity gradient stabilized facility and serves as the backbone for the various facility components. To maximize human performance, human comfort is stressed through zoning of living and working activities, maintaining a consistent local vertical orientation, providing crew interaction and viewing areas and providing crew return vehicles. Vehicle maintainability is accomplished through dual hangars, dual work cupolas, work modules, telerobotics and a fuel depot. Modularity is incorporated using Space Station Freedom module diameter, Space Station Freedom standard racks, and interchangeable interior partitions. It is intended that the final design be flexible and adaptable to provide a facility prototype that can service multiple mission profiles using modular space systems.
NextGen operations are associated with a variety of changes to the national airspace system (NAS) including changes to the allocation of roles and responsibilities among operators and automation, the use of new technologies and automation, additional information presented on the flight deck, and the entire concept of operations (ConOps). In the transition to NextGen airspace, aviation and air operations designers need to consider the implications of design or system changes on human performance and the potential for error. To ensure continued safety of the NAS, it will be necessary for researchers to evaluate design concepts and potential NextGen scenarios well before implementation. One approach for such evaluations is through human performance modeling. Human performance models (HPMs) provide effective tools for predicting and evaluating operator performance in systems. HPMs offer significant advantages over empirical, human-in-the-loop testing in that (1) they allow detailed analyses of systems that have not yet been built, (2) they offer great flexibility for extensive data collection, (3) they do not require experimental participants, and thus can offer cost and time savings. HPMs differ in their ability to predict performance and safety with NextGen procedures, equipment and ConOps. Models also vary in terms of how they approach human performance (e.g., some focus on cognitive processing, others focus on discrete tasks performed by a human, while others consider perceptual processes), and in terms of their associated validation efforts. The objectives of this research effort were to support the Federal Aviation Administration (FAA) in identifying HPMs that are appropriate for predicting pilot performance in NextGen operations, to provide guidance on how to evaluate the quality of different models, and to identify gaps in pilot performance modeling research, that could guide future research opportunities. This research effort is intended to help the FAA evaluate pilot modeling efforts and select the appropriate tools for future modeling efforts to predict pilot performance in NextGen operations.