Pub Date : 2005-03-05DOI: 10.1109/AERO.2005.1559729
J. Malin, D. Throop, L. Fleming, L. Flores
A method is presented for transforming functional requirements into system-of-subsystems function models. Text from requirements and risk tools is transformed into simple semantic models. An ontology of functions, entities and problems provides structure for the transformation and for deriving functional models. Functions, operands of functions and functional agents can be captured. Generic hazards and vulnerabilities can be identified for types of functions and operands. These models are transformed into functional architectures of connected subsystems. This approach permits application of graph analysis and lightweight simulation to investigate the effects of problems and countermeasures in scenarios. We discuss a hazard identification tool and hybrid simulation tool where these methods are being applied
{"title":"Transforming functional requirements and risk information into models for analysis and simulation","authors":"J. Malin, D. Throop, L. Fleming, L. Flores","doi":"10.1109/AERO.2005.1559729","DOIUrl":"https://doi.org/10.1109/AERO.2005.1559729","url":null,"abstract":"A method is presented for transforming functional requirements into system-of-subsystems function models. Text from requirements and risk tools is transformed into simple semantic models. An ontology of functions, entities and problems provides structure for the transformation and for deriving functional models. Functions, operands of functions and functional agents can be captured. Generic hazards and vulnerabilities can be identified for types of functions and operands. These models are transformed into functional architectures of connected subsystems. This approach permits application of graph analysis and lightweight simulation to investigate the effects of problems and countermeasures in scenarios. We discuss a hazard identification tool and hybrid simulation tool where these methods are being applied","PeriodicalId":117223,"journal":{"name":"2005 IEEE Aerospace Conference","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114383194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-03-05DOI: 10.1109/AERO.2005.1559719
P. Yeh, P. Armbruster, A. Kiely, B. Masschelein, G. Moury, C. Schaefer, C. Thiebaut
The consultative committee for space data systems (CCSDS) data compression working group has recently adopted a recommendation for image data compression, with a final release expected in 2005. The algorithm adopted in the recommendation consists of a two-dimensional discrete wavelet transform of the image, followed by progressive bit-plane coding of the transformed data. The algorithm can provide both lossless and lossy compression, and allows a user to directly control the compressed data volume or the fidelity with which the wavelet-transformed data can be reconstructed. The algorithm is suitable for both frame-based image data and scan-based sensor data, and has applications for near-Earth and deep-space missions. The standard will be accompanied by free software sources on a future Web site. An application-specific integrated circuit (ASIC) implementation of the compressor is currently under development. This paper describes the compression algorithm along with the requirements that drove the selection of the algorithm. Performance results and comparisons with other compressors are given for a test set of space images
{"title":"The new CCSDS image compression recommendation","authors":"P. Yeh, P. Armbruster, A. Kiely, B. Masschelein, G. Moury, C. Schaefer, C. Thiebaut","doi":"10.1109/AERO.2005.1559719","DOIUrl":"https://doi.org/10.1109/AERO.2005.1559719","url":null,"abstract":"The consultative committee for space data systems (CCSDS) data compression working group has recently adopted a recommendation for image data compression, with a final release expected in 2005. The algorithm adopted in the recommendation consists of a two-dimensional discrete wavelet transform of the image, followed by progressive bit-plane coding of the transformed data. The algorithm can provide both lossless and lossy compression, and allows a user to directly control the compressed data volume or the fidelity with which the wavelet-transformed data can be reconstructed. The algorithm is suitable for both frame-based image data and scan-based sensor data, and has applications for near-Earth and deep-space missions. The standard will be accompanied by free software sources on a future Web site. An application-specific integrated circuit (ASIC) implementation of the compressor is currently under development. This paper describes the compression algorithm along with the requirements that drove the selection of the algorithm. Performance results and comparisons with other compressors are given for a test set of space images","PeriodicalId":117223,"journal":{"name":"2005 IEEE Aerospace Conference","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117241014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-03-05DOI: 10.1109/AERO.2005.1559521
T. Thumthawatworn, T. Yeophantong, J. Daengdej
Many wireless sensor applications operate on a data set that requires a relatively high degree of precision. Small changes in the data collected from the working field by sensor nodes result in different outcomes as perceived by the data-sensitive application. A large amount of energy is consumed to maintain such sensitivity when all data detected by the sensor nodes are always transmitted to the receiver. Conversely, some applications do not need such high degree of precision. In this paper, we propose two approaches for determining the working schedule of each sensor node for precision-insensitive wireless sensor applications. In the first approach, Moving Average Base Station (MABS) model, the base station computes a decision model to be used by each sensor node in deciding whether or not data should be transmitted back to the base station. Data received by the base station is used to compute a statistical model which determines the acceptance range of the sensed data. These bounds, which are specific to each node, are transmitted to the respective nodes as a model for their decision. An alternative approach, termed moving average sensor mode (MASN) model, works in a similar fashion, but with the sensors capable of establishing the decision model on their own. The outcome is the ability to reduce energy consumption and, hence, extend the overall system lifetime
{"title":"Energy Conservation Approach for Precision-Insensitive Wireless Sensor Applications","authors":"T. Thumthawatworn, T. Yeophantong, J. Daengdej","doi":"10.1109/AERO.2005.1559521","DOIUrl":"https://doi.org/10.1109/AERO.2005.1559521","url":null,"abstract":"Many wireless sensor applications operate on a data set that requires a relatively high degree of precision. Small changes in the data collected from the working field by sensor nodes result in different outcomes as perceived by the data-sensitive application. A large amount of energy is consumed to maintain such sensitivity when all data detected by the sensor nodes are always transmitted to the receiver. Conversely, some applications do not need such high degree of precision. In this paper, we propose two approaches for determining the working schedule of each sensor node for precision-insensitive wireless sensor applications. In the first approach, Moving Average Base Station (MABS) model, the base station computes a decision model to be used by each sensor node in deciding whether or not data should be transmitted back to the base station. Data received by the base station is used to compute a statistical model which determines the acceptance range of the sensed data. These bounds, which are specific to each node, are transmitted to the respective nodes as a model for their decision. An alternative approach, termed moving average sensor mode (MASN) model, works in a similar fashion, but with the sensors capable of establishing the decision model on their own. The outcome is the ability to reduce energy consumption and, hence, extend the overall system lifetime","PeriodicalId":117223,"journal":{"name":"2005 IEEE Aerospace Conference","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123961281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-03-05DOI: 10.1109/AERO.2005.1559376
Charles H. Lee, K. Cheung, Charles. D. Edwards, Stuart. J. Kerridge, G. Noreen, Arvydas Vaisnys, Charles. D. Edwards, Stuart. J. Kerridge, G. Noreen
This paper describes a tool to aid orbit design called the Telecom Orbit Analysis and Simulation Tool (TOAST). By specifying the six orbital elements of an orbit, a time frame of interest, a horizon mask angle, and some telecom parameters such as transmitter power, frequency, antenna gains, antenna losses, required link margin, and received threshold powers for the rates, TOAST enables the user to view orbit performance as animations of two- or three-dimensional telecom metrics at any point on the planet (i.e., on global planetary maps). Supported metrics include: (i) number of contacts; (ii) total contact duration; (iii) maximum communication gap; (iv) maximum supportable rate; and (v) return data volume at a best single rate or with an adaptive rate, along with; (vi) the orbiter's footprint and (vii) local solar times. Unlike other existing tools, which generally provide geometry, view periods and link analysis for an orbiter with respect to a single location on the planet, TOAST generates telecom performance metrics over the entire planet. The added capabilities provide the user an extra degree of freedom in analyzing orbits and enable the user to focus on meeting specific mission requirements, such as what data rates can be supported, what data volume can be expected, and what the time gap will be between communication periods. Although TOAST can be used to study and select orbits about any planet, we describe here its use for missions to Mars. TOAST is being used to analyze candidate orbits for the 2009 Mars Telecommunications Orbiter mission. Telecom predicts generated by TOAST for MTO orbit candidates are laying a foundation for selecting the MTO service orbit. This paper presents numerical simulations and telecom predicts for four candidate MTO orbits.
{"title":"Orbit design based on global maps of telecom metrics","authors":"Charles H. Lee, K. Cheung, Charles. D. Edwards, Stuart. J. Kerridge, G. Noreen, Arvydas Vaisnys, Charles. D. Edwards, Stuart. J. Kerridge, G. Noreen","doi":"10.1109/AERO.2005.1559376","DOIUrl":"https://doi.org/10.1109/AERO.2005.1559376","url":null,"abstract":"This paper describes a tool to aid orbit design called the Telecom Orbit Analysis and Simulation Tool (TOAST). By specifying the six orbital elements of an orbit, a time frame of interest, a horizon mask angle, and some telecom parameters such as transmitter power, frequency, antenna gains, antenna losses, required link margin, and received threshold powers for the rates, TOAST enables the user to view orbit performance as animations of two- or three-dimensional telecom metrics at any point on the planet (i.e., on global planetary maps). Supported metrics include: (i) number of contacts; (ii) total contact duration; (iii) maximum communication gap; (iv) maximum supportable rate; and (v) return data volume at a best single rate or with an adaptive rate, along with; (vi) the orbiter's footprint and (vii) local solar times. Unlike other existing tools, which generally provide geometry, view periods and link analysis for an orbiter with respect to a single location on the planet, TOAST generates telecom performance metrics over the entire planet. The added capabilities provide the user an extra degree of freedom in analyzing orbits and enable the user to focus on meeting specific mission requirements, such as what data rates can be supported, what data volume can be expected, and what the time gap will be between communication periods. Although TOAST can be used to study and select orbits about any planet, we describe here its use for missions to Mars. TOAST is being used to analyze candidate orbits for the 2009 Mars Telecommunications Orbiter mission. Telecom predicts generated by TOAST for MTO orbit candidates are laying a foundation for selecting the MTO service orbit. This paper presents numerical simulations and telecom predicts for four candidate MTO orbits.","PeriodicalId":117223,"journal":{"name":"2005 IEEE Aerospace Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125967589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-03-05DOI: 10.1109/AERO.2005.1559406
D.L. Jones
The NASA Deep Space Network (DSN) is studying arrays of large numbers of small, mass-produced radio antennas as a cost-effective way to increase downlink sensitivity and data rates for future missions. An important issue for the operation of large arrays is the accuracy with which signals from hundreds of small antennas can be combined. This is particularly true at Ka band (32 GHz) where atmospheric phase variations can be large and rapidly changing. A number of algorithms exist to correct the phases of signals from individual antennas in the case where a spacecraft signal provides a useful signal-to-noise ratio (SNR) on time scales shorter than the atmospheric coherence time. However, for very weak spacecraft signals it will be necessary to rely on background natural radio sources to maintain array phasing. Very weak signals could result from a spacecraft emergency or by design, such as direct-to-Earth data transmissions from distant planetary atmospheric or surface probes using only low gain antennas. This paper considers the parameter space where external real-time phase calibration will be necessary, and what this requires in terms of array configuration and signal processing. The inherent limitations of this technique are also discussed
{"title":"Weak-signal phase calibration strategies for large DSN arrays","authors":"D.L. Jones","doi":"10.1109/AERO.2005.1559406","DOIUrl":"https://doi.org/10.1109/AERO.2005.1559406","url":null,"abstract":"The NASA Deep Space Network (DSN) is studying arrays of large numbers of small, mass-produced radio antennas as a cost-effective way to increase downlink sensitivity and data rates for future missions. An important issue for the operation of large arrays is the accuracy with which signals from hundreds of small antennas can be combined. This is particularly true at Ka band (32 GHz) where atmospheric phase variations can be large and rapidly changing. A number of algorithms exist to correct the phases of signals from individual antennas in the case where a spacecraft signal provides a useful signal-to-noise ratio (SNR) on time scales shorter than the atmospheric coherence time. However, for very weak spacecraft signals it will be necessary to rely on background natural radio sources to maintain array phasing. Very weak signals could result from a spacecraft emergency or by design, such as direct-to-Earth data transmissions from distant planetary atmospheric or surface probes using only low gain antennas. This paper considers the parameter space where external real-time phase calibration will be necessary, and what this requires in terms of array configuration and signal processing. The inherent limitations of this technique are also discussed","PeriodicalId":117223,"journal":{"name":"2005 IEEE Aerospace Conference","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129846962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-03-05DOI: 10.1109/AERO.2005.1559629
J. Noll, R. Steel
EKLOPS is the Enhanced Kernel Library for Operational Planning and Scheduling. This paper discusses the area of mission planning, and present EKLOPS as a generic mission planning solution proposed by the Mission Planning Group of Anite Systems GmbH. EKLOPS has evolved from mission planning systems that were developed under contracts of the European Space Agency. It implements an adaptive object model architecture to integrate the common elements of mission planning systems. The model of a specific satellite mission is expressed as metadata, which configure the MPS. Rules implement functions of the planning process for which a number of specific roles can be identified. The paper presents a language that has so far been utilized to express constraint-checking rules. The experience made with EKLOPS is shown using the examples of the ENVISAT and Mars Express missions. The generic nature of EKLOPS facilitates an extension of its usage outside the field of spacecraft operations planning
{"title":"EKLOPS: An Adaptive Approach to a Mission Planning System","authors":"J. Noll, R. Steel","doi":"10.1109/AERO.2005.1559629","DOIUrl":"https://doi.org/10.1109/AERO.2005.1559629","url":null,"abstract":"EKLOPS is the Enhanced Kernel Library for Operational Planning and Scheduling. This paper discusses the area of mission planning, and present EKLOPS as a generic mission planning solution proposed by the Mission Planning Group of Anite Systems GmbH. EKLOPS has evolved from mission planning systems that were developed under contracts of the European Space Agency. It implements an adaptive object model architecture to integrate the common elements of mission planning systems. The model of a specific satellite mission is expressed as metadata, which configure the MPS. Rules implement functions of the planning process for which a number of specific roles can be identified. The paper presents a language that has so far been utilized to express constraint-checking rules. The experience made with EKLOPS is shown using the examples of the ENVISAT and Mars Express missions. The generic nature of EKLOPS facilitates an extension of its usage outside the field of spacecraft operations planning","PeriodicalId":117223,"journal":{"name":"2005 IEEE Aerospace Conference","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129870729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-03-05DOI: 10.1109/AERO.2005.1559552
Jai Bansal, B. Orlowsky, L. Rockett
As integrated circuit dimensions scale downward the costs of the photolithographic masks used to manufacture microcircuits are becoming prohibitively high. And in today's highly competitive business environment, time to market is increasingly critical. Custom standard-cell ASICs are on the wrong side of these dynamics with their long lead times and the need to build a full mask set per part number. Structured ASICs offer an attractive alternative. Structured ASICs are developed from an inventoried base masterslice chip design by using generally only a few back-end masking levels to personalize the resulting ASIC function, saving mask costs and shortening lead times per circuit design. Structured ASICs strategically fill the trade space between FPGAs and custom ASICs. BAE Systems has developed a radiation hardened structured ASIC product offering for next-generation advanced military and space applications
{"title":"Structured ASIC Design for Space Systems Applications","authors":"Jai Bansal, B. Orlowsky, L. Rockett","doi":"10.1109/AERO.2005.1559552","DOIUrl":"https://doi.org/10.1109/AERO.2005.1559552","url":null,"abstract":"As integrated circuit dimensions scale downward the costs of the photolithographic masks used to manufacture microcircuits are becoming prohibitively high. And in today's highly competitive business environment, time to market is increasingly critical. Custom standard-cell ASICs are on the wrong side of these dynamics with their long lead times and the need to build a full mask set per part number. Structured ASICs offer an attractive alternative. Structured ASICs are developed from an inventoried base masterslice chip design by using generally only a few back-end masking levels to personalize the resulting ASIC function, saving mask costs and shortening lead times per circuit design. Structured ASICs strategically fill the trade space between FPGAs and custom ASICs. BAE Systems has developed a radiation hardened structured ASIC product offering for next-generation advanced military and space applications","PeriodicalId":117223,"journal":{"name":"2005 IEEE Aerospace Conference","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128423626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-03-05DOI: 10.1109/AERO.2005.1559687
Kagan Tumer, A. Agogino
The ability to assess risk in complex systems is one of the fundamental challenges facing the aerospace industry in general, and NASA in particular. First, such an ability allows for quantifiable trade-offs during the design stage of a mission. Second, it allows the monitoring of die health of the system while in operation. Because many of the difficulties in complex systems arise from the interactions among the subsystems, system health monitoring cannot solely focus on the health of those subsystems. Instead system level signatures that encapsulate the complex system interactions are needed. In this work, we present the entropy-scale (ES) and entropy-resolution (ER) system-level signatures that are both computationally tractable and encapsulate many of the salient characteristics of a system. These signatures are based on the change of entropy as a system is observed across different resolutions and scales. We demonstrate the use of the ES and ER signatures on artificial data streams and simple dynamical systems and show that they allow the unambiguous clustering of many types of systems, and therefore are good indicators of system health. We then show how these signatures can be applied to graphical data as well as data strings by using a simple "graph-walking" method. This method extracts a data stream from a graphical system representation (e.g., fault tree, software call graph) that conserves the properties of the graph. Finally we apply these signatures to analysis of software packages, and show that they provide significantly better correlation with risk markers than many standard metrics. These results indicate that proper system level signatures, coupled with detailed component-level analysis enable the automatic detection of potentially hazardous subsystem interactions in complex systems before they lead to system deterioration or failures
{"title":"Complexity signatures for system health monitoring","authors":"Kagan Tumer, A. Agogino","doi":"10.1109/AERO.2005.1559687","DOIUrl":"https://doi.org/10.1109/AERO.2005.1559687","url":null,"abstract":"The ability to assess risk in complex systems is one of the fundamental challenges facing the aerospace industry in general, and NASA in particular. First, such an ability allows for quantifiable trade-offs during the design stage of a mission. Second, it allows the monitoring of die health of the system while in operation. Because many of the difficulties in complex systems arise from the interactions among the subsystems, system health monitoring cannot solely focus on the health of those subsystems. Instead system level signatures that encapsulate the complex system interactions are needed. In this work, we present the entropy-scale (ES) and entropy-resolution (ER) system-level signatures that are both computationally tractable and encapsulate many of the salient characteristics of a system. These signatures are based on the change of entropy as a system is observed across different resolutions and scales. We demonstrate the use of the ES and ER signatures on artificial data streams and simple dynamical systems and show that they allow the unambiguous clustering of many types of systems, and therefore are good indicators of system health. We then show how these signatures can be applied to graphical data as well as data strings by using a simple \"graph-walking\" method. This method extracts a data stream from a graphical system representation (e.g., fault tree, software call graph) that conserves the properties of the graph. Finally we apply these signatures to analysis of software packages, and show that they provide significantly better correlation with risk markers than many standard metrics. These results indicate that proper system level signatures, coupled with detailed component-level analysis enable the automatic detection of potentially hazardous subsystem interactions in complex systems before they lead to system deterioration or failures","PeriodicalId":117223,"journal":{"name":"2005 IEEE Aerospace Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128501929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-03-05DOI: 10.1109/AERO.2005.1559699
M. Roemer, J. Dzakowic, R. Orsagh, C. Byington, G. Vachtsevanos
Impact Technologies and the Georgia Institute of Technology are developing a Web-based software application that will provide JSF (F-35) system suppliers with a comprehensive set of PHM verification and validation (V&V) resources which will include: standards and definitions, V&V metrics for detection, diagnosis, and prognosis, access to costly seeded fault data sets and example implementations, a collaborative user forum for the exchange of information, and an automated tool for impartially evaluating the performance and effectiveness of PHM technologies. This paper presents the development of the prototype software product to illustrate the feasibility of the techniques, methodologies, and approaches needed to verify and validate PHM capabilities. A team of JSF system suppliers has been assembled to contribute, provide feedback and make recommendations to the product under development. The approach being pursued for assessing the overall PHM system accuracy is to quantify the associated uncertainties at each of the individual levels of a PHM system, and build up the accumulated inaccuracies as information is processed through the PHM architecture
{"title":"Validation and verification of prognostic and health management technologies","authors":"M. Roemer, J. Dzakowic, R. Orsagh, C. Byington, G. Vachtsevanos","doi":"10.1109/AERO.2005.1559699","DOIUrl":"https://doi.org/10.1109/AERO.2005.1559699","url":null,"abstract":"Impact Technologies and the Georgia Institute of Technology are developing a Web-based software application that will provide JSF (F-35) system suppliers with a comprehensive set of PHM verification and validation (V&V) resources which will include: standards and definitions, V&V metrics for detection, diagnosis, and prognosis, access to costly seeded fault data sets and example implementations, a collaborative user forum for the exchange of information, and an automated tool for impartially evaluating the performance and effectiveness of PHM technologies. This paper presents the development of the prototype software product to illustrate the feasibility of the techniques, methodologies, and approaches needed to verify and validate PHM capabilities. A team of JSF system suppliers has been assembled to contribute, provide feedback and make recommendations to the product under development. The approach being pursued for assessing the overall PHM system accuracy is to quantify the associated uncertainties at each of the individual levels of a PHM system, and build up the accumulated inaccuracies as information is processed through the PHM architecture","PeriodicalId":117223,"journal":{"name":"2005 IEEE Aerospace Conference","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128216392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-03-05DOI: 10.1109/AERO.2005.1559364
L. Townsend
From time to time over the past several decades, designs utilizing active methods involving electromagnetic field configurations have been proposed for the purpose of protecting spacecraft crews from harmful space radiations. Designs affording protection from either solar energetic particle event protons or galactic cosmic rays or both have been proposed. Often these analyses are predicated upon simplified or even incorrect assumptions regarding the incident radiation spectra or their associated radiation risks and limits. At times the proponents of these designs make very optimistic assumptions about the abilities of the scientific and engineering communities to overcome existing technology gaps needed to move their designs from paper to practice. In this paper, various active shield methods proposed over the past several decades are reviewed and critiqued. Advantages and disadvantages of the proposed methods are presented. Shortcomings in the analyses of their shielding efficacies, where they exist, are described.
{"title":"Critical analysis of active shielding methods for space radiation protection","authors":"L. Townsend","doi":"10.1109/AERO.2005.1559364","DOIUrl":"https://doi.org/10.1109/AERO.2005.1559364","url":null,"abstract":"From time to time over the past several decades, designs utilizing active methods involving electromagnetic field configurations have been proposed for the purpose of protecting spacecraft crews from harmful space radiations. Designs affording protection from either solar energetic particle event protons or galactic cosmic rays or both have been proposed. Often these analyses are predicated upon simplified or even incorrect assumptions regarding the incident radiation spectra or their associated radiation risks and limits. At times the proponents of these designs make very optimistic assumptions about the abilities of the scientific and engineering communities to overcome existing technology gaps needed to move their designs from paper to practice. In this paper, various active shield methods proposed over the past several decades are reviewed and critiqued. Advantages and disadvantages of the proposed methods are presented. Shortcomings in the analyses of their shielding efficacies, where they exist, are described.","PeriodicalId":117223,"journal":{"name":"2005 IEEE Aerospace Conference","volume":"127 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129639061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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