206 research outputs found
Model Based Mission Assurance: NASA's Assurance Future
Model Based Systems Engineering (MBSE) is seeing increased application in planning and design of NASAs missions. This suggests the question: what will be the corresponding practice of Model Based Mission Assurance (MBMA)? Contemporaneously, NASAs Office of Safety and Mission Assurance (OSMA) is evaluating a new objectives based approach to standards to ensure that the Safety and Mission Assurance disciplines and programs are addressing the challenges of NASAs changing missions, acquisition and engineering practices, and technology. MBSE is a prominent example of a changing engineering practice. We use NASAs objectives-based strategy for Reliability and Maintainability as a means to examine how MBSE will affect assurance. We surveyed MBSE literature to look specifically for these affects, and find a variety of them discussed (some are anticipated, some are reported from applications to date). Predominantly these apply to the early stages of design, although there are also extrapolations of how MBSE practices will have benefits for testing phases. As the effort to develop MBMA continues, it will need to clearly and unambiguously establish the roles of uncertainty and risk in the system model. This will enable a variety of uncertainty-based analyses to be performed much more rapidly than ever before and has the promise to increase the integration of CRM (Continuous Risk Management) and PRA (Probabilistic Risk Analyses) even more fully into the project development life cycle. Various views and viewpoints will be required for assurance disciplines, and an over-arching viewpoint will then be able to more completely characterize the state of the project/program as well as (possibly) enabling the safety case approach for overall risk awareness and communication
Studies in the history of books and the book trade
The books and papers offered in this submission are concerned with the history of books and the book trade. Three papers (nos. 1, 2, 3) offer a theoretical and conceptual framework for historical studies of the book. In essence, it is argued that since the book is a societal object it can only be understood in a societal context. Consequently historical studies of books are concerned with far more than physical bibliography, important as that is. The writing, publishing and reading of books are activities which develop out of, and influence the further development of, political and economic systems. The political context of publishing and its legal status is of central concern to the book historian (nos. 12, 14, 15); so too are the mechanisms of sale and distribution (nos. 9, 10, 11, 16) and the relationships between the author who is the primary producer, and the publisher who provides his commercial link with the reader (no. 13). More specifically, the central group of works is concerned with the provincial book trade in 18th-century England. The general study (no. 8) is a wide-ranging survey, largely based on primary sources, of the development and operation of the complex systems which allowed the printed word to permeate English society at every level and in every part of the country between 1700 and 1800. Shorter studies consider some more detailed aspects of the same subject (nos. 4, 6, 7) and survey previous work in the field (no. 5 )
Design and analysis issues of integrated control systems for high-speed civil transports
A study was conducted to identify, rank, and define development plans for the critical guidance and control design and analysis issues as related to economically viable and environmentally acceptable high-speed civil transport. The issues were identified in a multistep process. First, pertinent literature on supersonic cruise aircraft was reviewed, and experts were consulted to establish the fundamental characteristics and problems inherent to supersonic cruise aircraft. Next, the advanced technologies and strategies being pursued for the high-speed civil transport were considered to determine any additional unique control problems the transport may have. Finally, existing technologies and methods were examined to determine their capabilities for the design and analysis of high-speed civil transport control systems and to identify the shortcomings and issues. Three priority levels - mandatory, highly beneficial, and desirable - were established. Within each of these levels, the issues were further ranked. Technology development plans for each issue were defined. Each plan contains a task breakdown and schedule
Bestsellers in the British book industry 1998-2005
Bestsellers in the British book industry 1998-200
British Bibliographical Journals: past present and future
Library and Information Science as an academic discipline and as formal professional training and education, evolved very slowly in the UK. The study of books develops as a product of enlightenment; librarians and scholars began to develop the lists of the early printed books with the Annales typographici of Maittaire (1719-41). In England, Thomas Frognall Dibdin (1776-1847) coined the word bibliomania to describe the phenomenon that was contributing to promote certain types of books as objects of fashion. Bibliomania proved to be a passing fad, but it influenced the future direction of bibliophily, and some actually still survive in whole or in part. Between mid- to late-19th century the continuous history book-related and professional librarianship journals in the United Kingdom began; history that is told up to the present day
Enabling Assurance in the MBSE Environment
A number of specific benefits that fit within the hallmarks of effective development are realized with implementation of model-based approaches to systems and assurance. Model Based Systems Engineering (MBSE) enabled by standardized modeling languages (e.g., SysML) is at the core. These benefits in the context of spaceflight system challenges can include: Improved management of complex development, Reduced risk in the development process, Improved cost management, Improved design decisions. With appropriate modeling techniques the assurance community can improve early oversight and insight into project development. NASA has shown the basic constructs of SysML in an MBSE environment offer several key advantages, within a Model Based Mission Assurance (MBMA) initiative
Model Based Systems Engineering for CubeSat Mission Reliability
Model Based Systems Engineering (MBSE) is moving to the forefront of small spacecraft development. The benefits of SysML as a language for the elucidation of the system architecture for CubeSats is well understood and is implemented in standard model formats. Concurrently, the benefits of the evolving development of MBSE for assurance has been recognized and is emerging as Model Based Mission Assurance (MBMA), which promises the development of integral assurance stakeholder views into the model as well as the production of useful products from the model. In this regard, the assurance organizations of NASA, ESA, and JAXA are exploring jointly the potential benefits of MBSE and MBMA in anticipation of future joint projects in which an architecture for a flight mission will be shared in a SysML model. Traditionally, only mission-critical aspects of large systems have been able to justify the time and expense of creating reliability analyses. This work aims to make these analyses practical for a wide range of missions, from small to large to support architectural design decisions, rapidly and cost effectively, across organizations. In additions to exploring basic modeling concepts and communicating over the model, the partners have shown that reliability analysis can be generated from the model. These include early Failure Modes, Effects, and Critically Analysis (FMECA) and Fault Tree Analysis (FTA) based on the simulated mission. The intent is to test basic meta-model frameworks and compare these results across the agencies. One such basic framework employs SysML state machines as the basis for developing FMEAs and FTAs. When failures are modeled using this framework, plugins (developed by NASA under a Small Business Innovation Research project) for the SysML tool are able to automatically to generate a FMECA table and Fault Trees.
The expected outcome of this project is a compilation of lessons learned across the 3 agencies (NASA-ESA-JAXA) to be shared with their assurance communities. In addition, comparisons and utility of SysML derived products from the model are planned. Finally, a framework for standardization to the extent possible will be proposed to facilitate model sharing in the future for more complex scenarios, as a result of lessons learned herein
A Framework for Reliability and Safety Analysis of Complex Space Missions
Long duration and complex mission scenarios are characteristics of NASA's human exploration of Mars, and will provide unprecedented challenges. Systems reliability and safety will become increasingly demanding and management of uncertainty will be increasingly important. NASA's current pioneering strategy recognizes and relies upon assurance of crew and asset safety. In this regard, flexibility to develop and innovate in the emergence of new design environments and methodologies, encompassing modeling of complex systems, is essential to meet the challenges
Advancing the Scientific Frontier with Increasingly Autonomous Systems
A close partnership between people and partially autonomous machines has
enabled decades of space exploration. But to further expand our horizons, our
systems must become more capable. Increasing the nature and degree of autonomy
- allowing our systems to make and act on their own decisions as directed by
mission teams - enables new science capabilities and enhances science return.
The 2011 Planetary Science Decadal Survey (PSDS) and on-going pre-Decadal
mission studies have identified increased autonomy as a core technology
required for future missions. However, even as scientific discovery has
necessitated the development of autonomous systems and past flight
demonstrations have been successful, institutional barriers have limited its
maturation and infusion on existing planetary missions. Consequently, the
authors and endorsers of this paper recommend that new programmatic pathways be
developed to infuse autonomy, infrastructure for support autonomous systems be
invested in, new practices be adopted, and the cost-saving value of autonomy
for operations be studied.Comment: 10 pages (compared to 8 submitted to PSADS), 2 figures, submitted to
National Academy of Sciences Planetary Science and Astrobiology Decadal
Survey 2023-203
Connectivity precedes function in the development of the visual word form area
What determines the cortical location at which a given functionally specific region will arise in development? We tested the hypothesis that functionally specific regions develop in their characteristic locations because of pre-existing differences in the extrinsic connectivity of that region to the rest of the brain. We exploited the visual word form area (VWFA) as a test case, scanning children with diffusion and functional imaging at age 5, before they learned to read, and at age 8, after they learned to read. We found the VWFA developed functionally in this interval and that its location in a particular child at age 8 could be predicted from that child's connectivity fingerprints (but not functional responses) at age 5. These results suggest that early connectivity instructs the functional development of the VWFA, possibly reflecting a general mechanism of cortical development.National Institutes of Health (U.S.) (Grant F32HD079169)Eunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.) (Grant F32HD079169)National Institutes of Health (U.S.) (Grant R01HD067312)Eunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.) (Grant R01HD067312
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