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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

An ad hoc map evaluation procedure

An ad hoc map evaluation procedure is proposed which is most suitable for evaluating low-resolution classification maps against high resolution ground truth maps, such as maps against interpreted aircraft photographs. Commonly practiced sampling and evaluation procedures are impracticable in this context because of difficulties in registration and in comparing the samples. This ad hoc procedure is designed to overcome these two major problems, and its practicability is discussed. Two widely accepted parameters are estimated by the new procedure; namely, the probability of correct classification and the proportion biases. Statistical qualifications are also provided.

Kan, E. P.↗
NASA NTRS1989

Expert systems should be more accurate than human experts - Evaluation procedures from human judgment and decisionmaking

Two procedures for the evaluation of the performance of expert systems are illustrated: one procedure evaluates predictive accuracy; the other procedure is complementary in that it uncovers the factors that contribute to predictive accuracy. Using these procedures, it is argued that expert systems should be more accurate than human experts in two senses. One sense is that expert systems must be more accurate to be cost-effective. Previous research is reviewed and original results are presented which show that simple statistical models typically perform better than human experts for the task of combining evidence from a given set of information sources. The results also suggest the second sense in which expert systems should be more accurate than human experts. They reveal that expert systems should share factors that contribute to human accuracy, but not factors that detract from human accuracy. Thus the thesis is that one should both require and expect systems to be more accurate than humans.

Levi, Keith↗
NASA NTRS1998

A Formal Approach for Designing and Evaluating Procedures

Operator interaction with modern control systems is a topic of great concern in high-risk industries such as nuclear power and commercial aviation. The issues associated with such systems focus on the ability of the operators (e.g., pilots) to achieve mission goals safely while containing failures. Operators must be able to interact safely and reliably with highly automatic and complex systems across the full spectrum of possible operating conditions, including normal, abnormal, and emergency situations. In environments such as commercial aviation, operator interaction with the machine is specified through a set of standard operating procedures (SOP). A procedure represents a collective agreement on the 'best' way to perform a given task. The intent of this paper is to suggest a formal methodology, for designing and evaluating procedures, that is both reliable and systematic. Our approach involves two major elements: a model of the machine and a list of the operator's task specifications (goals). We use formal modeling paradigms for describing the system and super-imposing on it the operator's tasks. Such paradigms, based on recent frameworks such as Statecharts and Hierarchical Hybrid Machines appear to be adequate methods for analyzing operator interaction with modern control systems. To illustrate this methodology, we model and analyze the sequence of actions for an emergency procedure. The procedure, Irregular Engine Start, for a medium-range aircraft, specifies the sequence of immediate actions that must be performed by the crew to avoid an uncontrolled rise in engine temperature during start-up. A model of engine behavior during a hot start is constructed. It also describes the various actions that can be taken by the crew and the resulting outcomes. The model is then opened up as a tree of all possible action sequences. This action tree allows us to trace the correct sequences necessary to achieve the desired end-goal (secure and shut down of the engine). In conclusion, we argue that the current process of designing and evaluating procedures can be improved. We discuss the implications of this approach for designing and evaluating this and other types of procedures. We conclude with insights about the benefits and limitation of this methodology, and offer suggestions for future research.

Degani, Asaf↗
NASA NTRS2006

Medical Operations Console Procedure Evaluation: BME Response to Crew Call Down for an Emergency

International Space Station (ISS) Mission Operations are managed by multiple flight control disciplines located at the lead Mission Control Center (MCC) at NASA-Johnson Space Center (JSC). ISS Medical Operations are supported by the complementary roles of Flight Surgeons (Surgeon) and Biomedical Engineer (BME) flight controllers. The Surgeon, a board certified physician, oversees all medical concerns of the crew and the BME provides operational and engineering support for Medical Operations Crew Health Care System. ISS Medical Operations is currently addressing the coordinated response to a crew call down for an emergent medical event, in particular when the BME is the only Medical Operations representative in MCC. In this case, the console procedure BME Response to Crew Call Down for an Emergency will be used. The procedure instructs the BME to contact a Surgeon as soon as possible, coordinate with other flight disciplines to establish a Private Medical Conference (PMC) for the crew and Surgeon, gather information from the crew if time permits, and provide Surgeon with pertinent console resources. It is paramount that this procedure is clearly written and easily navigated to assist the BME to respond consistently and efficiently. A total of five BME flight controllers participated in the study. Each BME participant sat in a simulated MCC environment at a console configured with resources specific to the BME MCC console and was presented with two scripted emergency call downs from an ISS crew member. Each participant used the procedure while interacting with analog MCC disciplines to respond to the crew call down. Audio and video recordings of the simulations were analyzed and each BME participant's actions were compared to the procedure. Structured debriefs were conducted at the conclusion of both simulations. The procedure was evaluated for its ability to elicit consistent responses from each BME participant. Trials were examined for deviations in procedure task completion and/or navigation, in particular the execution of the Surgeon call sequence. Debrief comments were used to analyze unclear procedural steps and to discern any discrepancies between the procedure and generally accepted BME actions. The sequence followed by BME participants differed considerably from the sequence intended by the procedure. Common deviations included the call sequence used to contact Surgeon, the content of BME and crew interaction and the gathering of pertinent console resources. Differing perceptions of task priority and imprecise language seem to have caused multiple deviations from the procedure s intended sequence. The study generated 40 recommendations for the procedure, of which 34 are being implemented. These recommendations address improving the clarity of the instructions, identifying training considerations, expediting Surgeon contact, improving cues for anticipated flight control team communication and identifying missing console tools.

Johnson-Troop↗
NASA NTRS1972

Automation of reliability evaluation procedures through CARE - The computer-aided reliability estimation program.

Description of an on-line interactive computer program called CARE (Computer-Aided Reliability Estimation) which can model self-repair and fault-tolerant organizations and perform certain other functions. Essentially CARE consists of a repository of mathematical equations defining the various basic redundancy schemes. These equations, under program control, are then interrelated to generate the desired mathematical model to fit the architecture of the system under evaluation. The mathematical model is then supplied with ground instances of its variables and is then evaluated to generate values for the reliability-theoretic functions applied to the model.

Mathur, F. P.↗
NASA NTRS1976

Data reduction and evaluation procedures

The computational procedures that are involved in exhaust emissions data reduction and the use of these computational procedures for determining the quality of the data that is obtained from exhaust measurements were considered. Four problem areas were calculated: (1) the various methods for performing the carbon balance, (2) the method for calculating water correction factors, (3) the method for calculating the exhaust molecular weight, and (4) assessing the quality of the data.

Mirsky, W.↗
NASA NTRS2010

Battery Separator Characterization and Evaluation Procedures for NASA's Advanced Lithium-Ion Batteries

To address the future performance and safety requirements for the electrical energy storage technologies that will enhance and enable future NASA manned aerospace missions, advanced rechargeable, lithium-ion battery technology development is being pursued within the scope of the NASA Exploration Technology Development Program s (ETDP's) Energy Storage Project. A critical cell-level component of a lithium-ion battery which significantly impacts both overall electrochemical performance and safety is the porous separator that is sandwiched between the two active cell electrodes. To support the selection of the optimal cell separator material(s) for the advanced battery technology and chemistries under development, laboratory characterization and screening procedures were established to assess and compare separator material-level attributes and associated separator performance characteristics.

Baldwin, Richard S.↗
NASA NTRS1986

Development of Space Station strut design

Candidate Space Station struts exhibiting high stiffness (38-40 msi modulus of elasticity) were manufactured and experimentally evaluated. One and two inch diameter aluminum-clad evaluation specimens were manufactured using a unique dry fiber resin injection process. Preliminary tests were performed on strut elements having 80 percent high-modulus graphite epoxy and 20 percent aluminum. Performed tests included modulus of elasticity, thermal cycling, and coefficient of thermal expansion. The paper describes the design approach, including an analytical assessment of strut thermal deformation behavior. The major thrust of this paper is the manufacturing process which produces aluminum-clad struts with precisely controlled properties which can be fine-tuned after fabrication. An impact test and evaluation procedure for evaluating toughness is described.

Johnson, R. R.↗