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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 181 records · Page 10

All sources NASA NTRS DOE OSTI

NASA NTRS1989

PVDaCS - A prototype knowledge-based expert system for certification of spacecraft data

On-line data management techniques to certify spacecraft information are mandated by increasing telemetry rates. Knowledge-based expert systems offer the ability to certify data electronically without the need for time-consuming human interaction. Issues of automatic certification are explored by designing a knowledge-based expert system to certify data from a scientific instrument, the Orbiter Ultraviolet Spectrometer, on an operating NASA planetary spacecraft, Pioneer Venus. The resulting rule-based system, called PVDaCS (Pioneer Venus Data Certification System), is a functional prototype demonstrating the concepts of a larger system design. A key element of the system design is the representation of an expert's knowledge through the usage of well ordered sequences. PVDaCS produces a certification value derived from expert knowledge and an analysis of the instrument's operation. Results of system performance are presented.

Wharton, Cathleen↗

NASA NTRS1994

AI and workflow automation: The prototype electronic purchase request system

Automating 'paper' workflow processes with electronic forms and email can dramatically improve the efficiency of those processes. However, applications that involve complex forms that are used for a variety of purposes or that require numerous and varied approvals often require additional software tools to ensure that (1) the electronic form is correctly and completely filled out, and (2) the form is routed to the proper individuals and organizations for approval. The prototype electronic purchase request (PEPR) system, which has been in pilot use at NASA Ames Research Center since December 1993, seamlessly links a commercial electronics forms package and a CLIPS-based knowledge system that first ensures that electronic forms are correct and complete, and then generates an 'electronic routing slip' that is used to route the form to the people who must sign it. The PEPR validation module is context-sensitive, and can apply different validation rules at each step in the approval process. The PEPR system is form-independent, and has been applied to several different types of forms. The system employs a version of CLIPS that has been extended to support AppleScript, a recently-released scripting language for the Macintosh. This 'scriptability' provides both a transparent, flexible interface between the two programs and a means by which a single copy of the knowledge base can be utilized by numerous remote users.

Compton, Michael M.↗

DOE OSTI2020

Application of Koopman operator for model-based control of fracture propagation and proppant transport in hydraulic fracturing operation

This work explores the application of the recently developed Koopman operator approach for model identification and feedback control of a hydraulic fracturing process. Controlling fracture propagation and proppant transport with precision is a challenge due in large part to the difficulty of constructing approximate models that accurately capture the characteristic moving boundary and highly-coupled dynamics exhibited by the process. Koopman operator theory is particularly attractive here as it offers a way to explicitly construct linear representations for even highly nonlinear dynamics. The method is data-driven and relies on lifting the states to an infinite-dimensional space of functions called observables where the dynamics are governed by a linear Koopman operator. Here this work considers two problems: (a) fracture geometry control, and (b) proppant concentration control. In both cases, an approximate linear model of the corresponding dynamics is constructed and used to design a model predictive controller (MPC). The manuscript shows that in the case of highly nonlinear dynamics, as observed in the proppant concentration, use of canonical functions in the observable basis fails. In such cases, a priori system knowledge can be leveraged to choose the required basis. The numerical experiments demonstrate that the Koopman linear model shows excellent agreement with the real system and successfully achieves the desired target values maximizing the oil and gas productivity. Additionally, due to its linear structure, the Koopman models allow convex MPC formulations that avoid any issues associated with nonlinear optimization.

42 ENGINEERING↗

NASA NTRS2008

Exhaustive Thresholds and Resistance Checkpoints

Once deployed, all intricate systems that operate for a long time (such as an airplane or chemical processing plant) experience degraded performance during operational lifetime. These can result from losses of integrity in subsystems and parts that generally do not materially impact the operation of the vehicle (e.g., the light behind the button that opens the sliding door of the minivan). Or it can result from loss of more critical parts or subsystems. Such losses need to be handled quickly in order to avoid loss of personnel, mission, or part of the system itself. In order to manage degraded systems, knowledge of its potential problem areas and the means by which these problems are detected should be developed during the initial development of the system. Once determined, a web of sensors is employed and their outputs are monitored with other system parameters while the system is in preparation or operation. Just gathering the data is only part of the story. The interpretation of the data itself and the response of the system must be carefully developed as well to avoid a mishap. Typically, systems use a test-threshold-response paradigm to process potential system faults. However, such processing sub-systems can suffer from errors and oversights of a consistent type, causing system aberrant behavior instead of expected system and recovery operations. In our study, we developed a complete checklist for determining the completeness of a fault system and its robustness to common processing and response difficulties.

Easton, Charles↗

NASA NTRS1991

Spacecraft crew procedures from paper to computers

Described here is a research project that uses human factors and computer systems knowledge to explore and help guide the design and creation of an effective Human-Computer Interface (HCI) for spacecraft crew procedures. By having a computer system behind the user interface, it is possible to have increased procedure automation, related system monitoring, and personalized annotation and help facilities. The research project includes the development of computer-based procedure system HCI prototypes and a testbed for experiments that measure the effectiveness of HCI alternatives in order to make design recommendations. The testbed will include a system for procedure authoring, editing, training, and execution. Progress on developing HCI prototypes for a middeck experiment performed on Space Shuttle Mission STS-34 and for upcoming medical experiments are discussed. The status of the experimental testbed is also discussed.

Oneal, Michael↗

NASA NTRS1992

An experimental methodology for a fuzzy set preference model

A flexible fuzzy set preference model first requires approximate methodologies for implementation. Fuzzy sets must be defined for each individual consumer using computer software, requiring a minimum of time and expertise on the part of the consumer. The amount of information needed in defining sets must also be established. The model itself must adapt fully to the subject's choice of attributes (vague or precise), attribute levels, and importance weights. The resulting individual-level model should be fully adapted to each consumer. The methodologies needed to develop this model will be equally useful in a new generation of intelligent systems which interact with ordinary consumers, controlling electronic devices through fuzzy expert systems or making recommendations based on a variety of inputs. The power of personal computers and their acceptance by consumers has yet to be fully utilized to create interactive knowledge systems that fully adapt their function to the user. Understanding individual consumer preferences is critical to the design of new products and the estimation of demand (market share) for existing products, which in turn is an input to management systems concerned with production and distribution. The question of what to make, for whom to make it and how much to make requires an understanding of the customer's preferences and the trade-offs that exist between alternatives. Conjoint analysis is a widely used methodology which de-composes an overall preference for an object into a combination of preferences for its constituent parts (attributes such as taste and price), which are combined using an appropriate combination function. Preferences are often expressed using linguistic terms which cannot be represented in conjoint models. Current models are also not implemented an individual level, making it difficult to reach meaningful conclusions about the cause of an individual's behavior from an aggregate model. The combination of complex aggregate models and vague linguistic preferences has greatly limited the usefulness and predictive validity of existing preference models. A fuzzy set preference model that uses linguistic variables and a fully interactive implementation should be able to simultaneously address these issues and substantially improve the accuracy of demand estimates. The parallel implementation of crisp and fuzzy conjoint models using identical data not only validates the fuzzy set model but also provides an opportunity to assess the impact of fuzzy set definitions and individual attribute choices implemented in the interactive methodology developed in this research. The generalized experimental tools needed for conjoint models can also be applied to many other types of intelligent systems.

Turksen, I. B.↗

DOE OSTI2024

Equity and modeling in sustainability science: Examples and opportunities throughout the process

Equity is core to sustainability, but current interventions to enhance sustainability often fall short in adequately addressing this linkage. Models are important tools for informing action, and their development and use present opportunities to center equity in process and outcomes. This Perspective highlights progress in integrating equity into systems modeling in sustainability science, as well as key challenges, tensions, and future directions. We present a conceptual framework for equity in systems modeling, focused on its distributional, procedural, and recognitional dimensions. We discuss examples of how modelers engage with these different dimensions throughout the modeling process and from across a range of modeling approaches and topics, including water resources, energy systems, air quality, and conservation. Synthesizing across these examples, we identify significant advances in enhancing procedural and recognitional equity by reframing models as tools to explore pluralism in worldviews and knowledge systems; enabling models to better represent distributional inequity through new computational techniques and data sources; investigating the dynamics that can drive inequities by linking different modeling approaches; and developing more nuanced metrics for assessing equity outcomes. We also identify important future directions, such as an increased focus on using models to identify pathways to transform underlying conditions that lead to inequities and move toward desired futures. By looking at examples across the diverse fields within sustainability science, we argue that there are valuable opportunities for mutual learning on how to use models more effectively as tools to support sustainable and equitable futures.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS2016

Portable Life Support System 2.5 Fan Design and Development

NASA is building a high-fidelity prototype of an advanced Portable Life Support System (PLSS) as part of the Advanced Exploration Systems Program. This new PLSS, designated as PLSS 2.5, will advance component technologies and systems knowledge to inform a future flight program. The oxygen ventilation loop of its predecessor, PLSS 2.0, was driven by a centrifugal fan developed using specifications from the Constellation Program. PLSS technology and system parameters have matured to the point where the existing fan will not perform adequately for the new prototype. In addition, areas of potential improvement were identified with the PLSS 2.0 fan that could be addressed in a new design. As a result, a new fan was designed and tested for the PLSS 2.5. The PLSS 2.5 fan is a derivative of the one used in PLSS 2.0, and it uses the same nonmetallic, canned motor, with a larger volute and impeller to meet the higher pressure drop requirements of the PLSS 2.5 ventilation loop. The larger impeller allows it to operate at rotational speeds that are matched to rolling element bearings, and which create reasonably low impeller tip speeds consistent with prior, oxygen-rated fans. Development of the fan also considered a shrouded impeller design that could allow larger clearances for greater oxygen safety, assembly tolerances and particle ingestion. This paper discusses the design, manufacturing and performance testing of the new fans.

Quinn, Gregory↗

NASA NTRS1962

Analysis of the Range and Range Rate Tracking System

The "range and range rate"' (r(sub i) + r(sub i)) system in its very simplest form is described. In particular, the errors in position and velocity are treated using pessimistic values of the measured quantities r(sub i) and r(sub i). Thus, a realistic evaluation of tracking qualities can be made for different orbits over certain tracking stations. The range and range rate system briefly described in this paper is a high-precision tracking system. Knowledge of the uncertainty in position δ(sub xi) is important, but knowledge of the uncertainty of the velocity vector δ(sub xi) is of the utmost importance. Thus the use of coherent Doppler measurements to determine the velocity has a great advantage over any pulsed system and, in addition, permits extremely narrow frequency bandwidths (in the order of 10 to 100 cps) to be employed, reducing the power requirements considerably. The basis for using range r(sub i) and range rate r(sub i) only is the fact that r(sub i) and r(sub i) can be measured to very high precision, thus furnishing r and r with low errors. The nature of these errors is discussed.

Vonbun, F. O.↗

NASA NTRS2015

PLSS 2.5 Fan Design and Development

Quinn, Gregory↗

NASA NTRS2018

Automated Impact Assessment: A New Approach to ISS Payload Operations Anomaly Response

The International Space Station (ISS) Payload Operations and Integration Center (POIC) is undergoing rapid growth as the space station program focuses on science and commercial activities. The ISS is expanding its onboard capabilities to support additional science activities. In parallel, the POIC is expanding the capabilities of our operations tools to support the higher pace of payload activities being executed each week. An effect of these changes is that anomaly resolution has become more challenging. In the event of a real-time system fault, operators are responsible for analyzing telemetry displays, anomaly monitoring tools, documentation, and system models in order to produce failure impacts and recovery strategies. This approach to operations relies on the operator to ingest, process, and analyze information from an array of deterministic sources to provide actionable data on impacted systems and activities. Changing the existing approach of anomaly response is necessary if the ISS community is to succeed in the age of science and commercialization of space. The creation of a tool that captures deterministic technical systems knowledge and integrates existing telemetry, documentation, and planning information will allow the burden of impact assessment to be automated, thereby allowing the operator to focus on non-deterministic tasks, such as recovering failed systems and restoring critical payload operations.

Hall, R. Mason↗

NASA NTRS2015

PLSS 2.5 Fan Design and Development

NASA is building a high fidelity prototype of an advanced portable life support system (PLSS) as part of the Advanced Exploration Systems Program. This new PLSS, designated as PLSS 2.5, will advance component technologies and systems knowledge in order to inform a future flight program. The oxygen ventilation loop of its predecessor, PLSS 2.0, is driven by a centrifugal fan developed using specifications from over five years ago. PLSS technology and system parameters have matured to the point where the existing fan will not perform adequately for the new prototype. In addition, areas of potential improvement have been identified with the existing fan that could be addressed in a new design. As a result, a new fan was designed and tested for the PLSS 2.5. The PLSS 2.5 fan is a derivative of the one used in PLSS 2.0. It uses the same basic non-metallic can around the motor, but with a larger volute and impeller to meet the higher pressure drop requirements of the PLSS 2.5 loop. This allows it to operate at rotational speeds that are matched to rolling element bearings, and which create reasonably low impeller tip speeds. Development of the fan also considered a shrouded impeller design that allows larger clearances for greater oxygen safety and better performance.

Converse, David↗

NASA NTRS1962

Analysis of the ''Range and Range Rate'' Tracking System

The "Range and Range Rate" (r(sub j) + r ̇(sub j)) System in its very simplest form is described. In particular, the errors in position and velocity are treated usingpessimistic values of the measured quantities r(sub j) and r ̇(sub j). Thus, a realistic evaluation of tracking qualities can be made for different orbits over certain tracking stations. The Range and Range Rate System briefly described in this report is a high precision tracking system. Knowledge of the uncertainty in position δ (sub x(sub i) is important, but knowledge of the uncertainty of the velocity vector δ (sub x(sub i) is of the utmost importance. Thus the use of coherent Doppler measurements to determine the velocity has a great advantage over any pulsed system and, in addition, permits extremely narrow frequency bands (in the order of 10 to 100 cps) to be employed, reducing the power requirements considerably. The basis for using range r(sub j) and range rate r ̇(sub j) only is the fact that r(sub j) and r ̇(sub j) can be measured to very high precision, thus furnishing r and r with low errors. The nature of these errors is discussed.

Tracking system↗

NASA NTRS1988

Spacecraft environmental anomalies expert system

A microcomputer-based expert system is being developed at the Aerospace Corporation Space Sciences Laboratory to assist in the diagnosis of satellite anomalies caused by the space environment. The expert system is designed to address anomalies caused by surface charging, bulk charging, single event effects and total radiation dose. These effects depend on the orbit of the satellite, the local environment (which is highly variable), the satellite exposure time and the hardness of the circuits and components of the satellite. The expert system is a rule-based system that uses the Texas Instruments Personal Consultant Plus expert system shell. The completed expert system knowledge base will include 150 to 200 rules, as well as a spacecraft attributes database, an historical spacecraft anomalies database, and a space environment database which is updated in near real-time. Currently, the expert system is undergoing development and testing within the Aerospace Corporation Space Sciences Laboratory.

Koons, H. C.↗

NASA NTRS2006

Marshall Space Flight Center Propulsion Systems Department (PSD) Knowledge Management (KM) Initiative

NASA Marshall Space Flight Center's Propulsion Systems Department (PSD) is four months into a fifteen month Knowledge Management (KM) initiative to support enhanced engineering decision making and analyses, faster resolution of anomalies (near-term) and effective, efficient knowledge infused engineering processes, reduced knowledge attrition, and reduced anomaly occurrences (long-term). The near-term objective of this initiative is developing a KM Pilot project, within the context of a 3-5 year KM strategy, to introduce and evaluate the use of KM within PSD. An internal NASA/MSFC PSD KM team was established early in project formulation to maintain a practitioner, user-centric focus throughout the conceptual development, planning and deployment of KM technologies and capabilities within the PSD. The PSD internal team is supported by the University of Alabama's Aging Infrastructure Systems Center of Excellence (AISCE), lntergraph Corporation, and The Knowledge Institute. The principle product of the initial four month effort has been strategic planning of PSD KNI implementation by first determining the "as is" state of KM capabilities and developing, planning and documenting the roadmap to achieve the desired "to be" state. Activities undertaken to suppo~th e planning phase have included data gathering; cultural surveys, group work-sessions, interviews, documentation review, and independent research. Assessments and analyses have beon pedormed including industry benchmarking, related local and Agency initiatives, specific tools and techniques used and strategies for leveraging existing resources, people and technology to achieve common KM goals. Key findings captured in the PSD KM Strategic Plan include the system vision, purpose, stakeholders, prioritized strategic objectives mapped to the top ten practitioner needs and analysis of current resource usage. Opportunities identified from research, analyses, cultural1KM surveys and practitioner interviews include: executive and senior management sponsorship, KM awareness, promotion and training, cultural change management, process improvement, leveraging existing resources and new innovative technologies to align with other NASA KM initiatives (convergence: the big picture). To enable results based incremental implementation and future growth of the KM initiative, key performance measures have been identified including stakeholder value, system utility, learning and growth (knowledge capture, sharing, reduced anomaly recurrence), cultural change, process improvement and return-on-investment. The next steps for the initial implementation spiral (focused on SSME Turbomachinery) have been identified, largely based on the organization and compilation of summary level engineering process models, data capture matrices, functional models and conceptual-level svstems architecture. Key elements include detailed KM requirements definition, KM technology architecture assessment, - evaluation and selection, deployable KM Pilot design, development, implementation and evaluation, and justifying full implementation (estimated Return-on-Investment). Features identified for the notional system architecture include the knowledge presentation layer (and its components), knowledge network layer (and its components), knowledge storage layer (and its components), User Interface and capabilities. This paper provides a snapshot of the progress to date, the near term planning for deploying the KM pilot project and a forward look at results based growth of KM capabilities with-in the MSFC PSD.

Caraccioli, Paul↗

NASA NTRS2020

Pattern Identification - A Foundation for Research in the Emphasis of Design Patterns in Systems Engineering and Knowledge Capture

Pattern Language describes the morphology and functionality of a system in the absence of design particulars. Harnessing this capability will provide the Systems Engineering discipline a means of managing the development of increasingly complex systems with increasingly distributed design teams while capturing and retaining knowledge for future generations. Pattern Language is a syntax for describing, and structurally relating, design patterns. Design patterns contextually describe the application of domain knowledge in the engineered solution to the force balance problem. The parallels between pattern recognition and application, as a fundamental stage of human learning, and pattern observation within a complex system, suggests pattern language may be a valuable tool in the capture and dissemination of knowledge. Pattern application has enjoyed considerable study over the last several decades, however much of this work has focused on the replication of design particulars. This work returns to the roots of Pattern Language and explores the utility of patterns as an architectural description and guide, and knowledge capture method, for complex system development beginning with the identification of a time proven design pattern.

Russell, Samuel P.↗

NASA NTRS1989

Use of artificial intelligence in supervisory control

Viewgraphs describing the design and testing of an intelligent decision support system called OFMspert are presented. In this expert system, knowledge about the human operator is represented through an operator/system model referred to as the OFM (Operator Function Model). OFMspert uses the blackboard model of problem solving to maintain a dynamic representation of operator goals, plans, tasks, and actions given previous operator actions and current system state. Results of an experiment to assess OFMspert's intent inferencing capability are outlined. Finally, the overall design philosophy for an intelligent tutoring system (OFMTutor) for operators of complex dynamic systems is summarized.

Cohen, Aaron↗

NASA NTRS2014

Concepts to Support HRP Integration Using Publications and Modeling

Initial efforts are underway to enhance the Human Research Program (HRP)'s identification and support of potential cross-disciplinary scientific collaborations. To increase the emphasis on integration in HRP's science portfolio management, concepts are being explored through the development of a set of tools. These tools are intended to enable modeling, analysis, and visualization of the state of the human system in the spaceflight environment; HRP's current understanding of that state with an indication of uncertainties; and how that state changes due to HRP programmatic progress and design reference mission definitions. In this talk, we will discuss proof-of-concept work performed using a subset of publications captured in the HRP publications database. The publications were tagged in the database with words representing factors influencing health and performance in spaceflight, as well as with words representing the risks HRP research is reducing. Analysis was performed on the publication tag data to identify relationships between factors and between risks. Network representations were then created as one type of visualization of these relationships. This enables future analyses of the structure of the networks based on results from network theory. Such analyses can provide insights into HRP's current human system knowledge state as informed by the publication data. The network structure analyses can also elucidate potential improvements by identifying network connections to establish or strengthen for maximized information flow. The relationships identified in the publication data were subsequently used as inputs to a model captured in the Systems Modeling Language (SysML), which functions as a repository for relationship information to be gleaned from multiple sources. Example network visualization outputs from a simple SysML model were then also created to compare to the visualizations based on the publication data only. We will also discuss ideas for building upon this proof-of-concept work to further support an integrated approach to human spaceflight risk reduction.

Mindock, J.↗