Pub Date : 2010-03-06DOI: 10.1109/AERO.2010.5446841
S. Saha, B. Saha, A. Saxena, K. Goebel
Distributed prognostics architecture design is an enabling step for efficient implementation of health management systems. 12A major challenge encountered in such design is formulation of optimal distributed prognostics algorithms. In this paper, we present a distributed GPR based prognostics algorithm whose target platform is a wireless sensor network. In addition to challenges encountered in a distributed implementation, a wireless network poses constraints on communication patterns, thereby making the problem more challenging. The prognostics application that was used to demonstrate our new algorithms is battery prognostics. In order to present trade-offs within different prognostic approaches, we present comparison with the distributed implementation of a particle filter based prognostics for the same battery data.
{"title":"Distributed prognostic health management with gaussian process regression","authors":"S. Saha, B. Saha, A. Saxena, K. Goebel","doi":"10.1109/AERO.2010.5446841","DOIUrl":"https://doi.org/10.1109/AERO.2010.5446841","url":null,"abstract":"Distributed prognostics architecture design is an enabling step for efficient implementation of health management systems. 12A major challenge encountered in such design is formulation of optimal distributed prognostics algorithms. In this paper, we present a distributed GPR based prognostics algorithm whose target platform is a wireless sensor network. In addition to challenges encountered in a distributed implementation, a wireless network poses constraints on communication patterns, thereby making the problem more challenging. The prognostics application that was used to demonstrate our new algorithms is battery prognostics. In order to present trade-offs within different prognostic approaches, we present comparison with the distributed implementation of a particle filter based prognostics for the same battery data.","PeriodicalId":378029,"journal":{"name":"2010 IEEE Aerospace Conference","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123777084","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 : 2010-03-06DOI: 10.1109/AERO.2010.5446669
M. Juliato, C. Gebotys
The growing demand for secure communications has lead to the utilization of cryptographic mechanisms on-board spacecrafts. However, that it not a trivial task due to sensitivity of cryptographic primitives to bit-flips, which are commonly caused by the radiation found in space. On-board processing has mitigated single event upsets (SEUs) by employing the traditional triple modular redundancy (TMR), but that technique incurs into huge area and energy penalties. This paper introduces an efficient approach to achieve fault tolerance in data origin authentication mechanisms based on the Keyed-Hash Message Authentication Code (HMAC). The proposed scheme achieves very high resistance against SEUs while reducing implementation area requirements and energy consumption compared to TMR. Results obtained through FPGA implementation show that HMAC-SHA512 utilizes 53% less area and consumes 25% less energy compared to the traditional TMR technique. Furthermore, the memory and registers of this hardware module are respectively 386 and 1140 times more resistant against SEUs than TMR. These results are crucial for substituting TMR with more efficient strategies therefore contributing to the achievement of higher levels of security in space systems.
{"title":"An efficient fault-tolerance technique for the Keyed-Hash Message Authentication Code","authors":"M. Juliato, C. Gebotys","doi":"10.1109/AERO.2010.5446669","DOIUrl":"https://doi.org/10.1109/AERO.2010.5446669","url":null,"abstract":"The growing demand for secure communications has lead to the utilization of cryptographic mechanisms on-board spacecrafts. However, that it not a trivial task due to sensitivity of cryptographic primitives to bit-flips, which are commonly caused by the radiation found in space. On-board processing has mitigated single event upsets (SEUs) by employing the traditional triple modular redundancy (TMR), but that technique incurs into huge area and energy penalties. This paper introduces an efficient approach to achieve fault tolerance in data origin authentication mechanisms based on the Keyed-Hash Message Authentication Code (HMAC). The proposed scheme achieves very high resistance against SEUs while reducing implementation area requirements and energy consumption compared to TMR. Results obtained through FPGA implementation show that HMAC-SHA512 utilizes 53% less area and consumes 25% less energy compared to the traditional TMR technique. Furthermore, the memory and registers of this hardware module are respectively 386 and 1140 times more resistant against SEUs than TMR. These results are crucial for substituting TMR with more efficient strategies therefore contributing to the achievement of higher levels of security in space systems.","PeriodicalId":378029,"journal":{"name":"2010 IEEE Aerospace Conference","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121494521","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 : 2010-03-06DOI: 10.1109/AERO.2010.5446779
R. Drury, A. Tsourdos, A. Cooke
The optimality of a solution to a minimum-time aircraft trajectory generation problem depends on the closeness of the generated airspeed to the maximum airspeed that satisfies all path and boundary constraints. Airspeed is typically determined by nonlinear constrained optimization, hence the degree of the airspeed parameterization affects optimality and computational speed. An alternative approach, directly evaluating maximum feasible airspeed, is described and compared with the optimization approach. Results using Chebyshev polynomials show that, in isolation, parameterizations of degree 8–10 deliver a good trade-off between high degree for optimality and low degree for speed. However, directly evaluating airspeed is closer to optimality and not prone to convergence to a local solution. Accuracy of evaluation of the maxima of constrained variables is investigated using global Chebyshev, local quadratic, and local cubic, interpolation, and results show that quadratic interpolation in particular is computationally efficient, increasing speed while maintaining accuracy.
{"title":"Real-time trajectory generation: Improving the optimality and speed of an inverse dynamics method","authors":"R. Drury, A. Tsourdos, A. Cooke","doi":"10.1109/AERO.2010.5446779","DOIUrl":"https://doi.org/10.1109/AERO.2010.5446779","url":null,"abstract":"The optimality of a solution to a minimum-time aircraft trajectory generation problem depends on the closeness of the generated airspeed to the maximum airspeed that satisfies all path and boundary constraints. Airspeed is typically determined by nonlinear constrained optimization, hence the degree of the airspeed parameterization affects optimality and computational speed. An alternative approach, directly evaluating maximum feasible airspeed, is described and compared with the optimization approach. Results using Chebyshev polynomials show that, in isolation, parameterizations of degree 8–10 deliver a good trade-off between high degree for optimality and low degree for speed. However, directly evaluating airspeed is closer to optimality and not prone to convergence to a local solution. Accuracy of evaluation of the maxima of constrained variables is investigated using global Chebyshev, local quadratic, and local cubic, interpolation, and results show that quadratic interpolation in particular is computationally efficient, increasing speed while maintaining accuracy.","PeriodicalId":378029,"journal":{"name":"2010 IEEE Aerospace Conference","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121575703","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 : 2010-03-06DOI: 10.1109/AERO.2010.5446979
B. Bortnik, J. P. Kirby, J. Lambert
In this paper we present the use of metallic waveguides as optical Raman probes for identification of various organic and inorganic compounds. In contrast to silica waveguides, metallic capillaries possess significant space savings and robust mechanical properties allowing the employment of such probes in hostile atmosphere and space environments. Furthermore, recent fabrication advances have produced metallic waveguides with low loss in the ultraviolet region, allowing the use of ultraviolet light as an excitation source in Raman spectroscopy, thereby decreasing background noise from sample and instrument fluorescence. Accordingly, we will present encouraging experimental results on the implementation of Raman spectroscopy using these metal capillaries and discuss their potential application to future space missions. This work is being developed as a NASA Planetary Instrument Definition and Development (PIDDP) task.
{"title":"Rugged compact metallized capillary Raman probe for material identification in hostile environments","authors":"B. Bortnik, J. P. Kirby, J. Lambert","doi":"10.1109/AERO.2010.5446979","DOIUrl":"https://doi.org/10.1109/AERO.2010.5446979","url":null,"abstract":"In this paper we present the use of metallic waveguides as optical Raman probes for identification of various organic and inorganic compounds. In contrast to silica waveguides, metallic capillaries possess significant space savings and robust mechanical properties allowing the employment of such probes in hostile atmosphere and space environments. Furthermore, recent fabrication advances have produced metallic waveguides with low loss in the ultraviolet region, allowing the use of ultraviolet light as an excitation source in Raman spectroscopy, thereby decreasing background noise from sample and instrument fluorescence. Accordingly, we will present encouraging experimental results on the implementation of Raman spectroscopy using these metal capillaries and discuss their potential application to future space missions. This work is being developed as a NASA Planetary Instrument Definition and Development (PIDDP) task.","PeriodicalId":378029,"journal":{"name":"2010 IEEE Aerospace Conference","volume":"130 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122658622","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 : 2010-03-06DOI: 10.1109/AERO.2010.5446919
S. Sud, Edward B. Page
Cellular communications systems suffer from co-channel interference (CCI), due to signals from adjacent cells interfering with each other. Conventional demodulation techniques have relied on interference rejection to extract only the highest power signal. Recently, a joint reduced rank model-based demodulator (J-RRMBD) was presented that extracts two or more co-channel signals using continuous phase modulation (CPM) simultaneously. The technique is based upon a root selection algorithm using forward-backward linear prediction (FBLP), whereby multiple unequal powered signals are extracted by choosing the highest powered roots. Using synchronous continuous phase frequency shift keying (CPFSK) signals, the algorithm has been shown to provide up to 5 dB improvement over the conventional quadrature demodulator (QD) and single user model-based demodulator (MBD), which extracts only the highest powered user. In this paper, we apply the technique to received asynchronous Gaussian Minimum Shift Keying (GMSK) signals with unknown frequency offsets, encountered in terrestrial GSM networks. We compare performance to a joint Viterbi demodulator when two co-channel signals are present and show that the new technique provides an order of magnitude reduction in bit error rate (BER), and can more reliably demodulate signals with few samples as long as the carrier-to-interference ratio (CIR) ≥ 3 dB. When CIR ≪ 5 dB, a single user version of the algorithm provides performance improvement up to 7 dB over the Viterbi algorithm.
{"title":"Performance of the joint reduced rank model-based demodulator for asynchronous co-channel GMSK signals","authors":"S. Sud, Edward B. Page","doi":"10.1109/AERO.2010.5446919","DOIUrl":"https://doi.org/10.1109/AERO.2010.5446919","url":null,"abstract":"Cellular communications systems suffer from co-channel interference (CCI), due to signals from adjacent cells interfering with each other. Conventional demodulation techniques have relied on interference rejection to extract only the highest power signal. Recently, a joint reduced rank model-based demodulator (J-RRMBD) was presented that extracts two or more co-channel signals using continuous phase modulation (CPM) simultaneously. The technique is based upon a root selection algorithm using forward-backward linear prediction (FBLP), whereby multiple unequal powered signals are extracted by choosing the highest powered roots. Using synchronous continuous phase frequency shift keying (CPFSK) signals, the algorithm has been shown to provide up to 5 dB improvement over the conventional quadrature demodulator (QD) and single user model-based demodulator (MBD), which extracts only the highest powered user. In this paper, we apply the technique to received asynchronous Gaussian Minimum Shift Keying (GMSK) signals with unknown frequency offsets, encountered in terrestrial GSM networks. We compare performance to a joint Viterbi demodulator when two co-channel signals are present and show that the new technique provides an order of magnitude reduction in bit error rate (BER), and can more reliably demodulate signals with few samples as long as the carrier-to-interference ratio (CIR) ≥ 3 dB. When CIR ≪ 5 dB, a single user version of the algorithm provides performance improvement up to 7 dB over the Viterbi algorithm.","PeriodicalId":378029,"journal":{"name":"2010 IEEE Aerospace Conference","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131369127","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 : 2010-03-06DOI: 10.1109/AERO.2010.5446768
David J. Anderson, J. Dankanich, M. Munk, E. Pencil, L. Liou
Since its inception in 2001, the objective of the In-Space12 Propulsion Technology (ISPT) project has been developing and delivering in-space propulsion technologies that enable or enhance NASA robotic science missions. These in-space propulsion technologies are applicable, and potentially enabling for future NASA flagship and sample return missions currently under consideration, as well as having broad applicability to future Discovery and New Frontiers mission solicitations. This paper provides status of the technology development, applicability, and availability of in-space propulsion technologies that recently completed, or will be completing within the next year, their technology development and are ready for infusion into missions. The paper also describes the ISPT project's future focus on propulsion for sample return missions.
{"title":"The NASA In-Space Propulsion Technology project's current products and future directions","authors":"David J. Anderson, J. Dankanich, M. Munk, E. Pencil, L. Liou","doi":"10.1109/AERO.2010.5446768","DOIUrl":"https://doi.org/10.1109/AERO.2010.5446768","url":null,"abstract":"Since its inception in 2001, the objective of the In-Space12 Propulsion Technology (ISPT) project has been developing and delivering in-space propulsion technologies that enable or enhance NASA robotic science missions. These in-space propulsion technologies are applicable, and potentially enabling for future NASA flagship and sample return missions currently under consideration, as well as having broad applicability to future Discovery and New Frontiers mission solicitations. This paper provides status of the technology development, applicability, and availability of in-space propulsion technologies that recently completed, or will be completing within the next year, their technology development and are ready for infusion into missions. The paper also describes the ISPT project's future focus on propulsion for sample return missions.","PeriodicalId":378029,"journal":{"name":"2010 IEEE Aerospace Conference","volume":"106 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116522107","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}
The Soft X-Ray Telescope (SXT) modules are the fundamental focusing assemblies on NASA's next major X-ray telescope mission, the International X-Ray Observatory (IXO). {su12]The preliminary design and analysis of these assemblies has been completed, addressing the major engineering challenges and leading to an understanding of the factors effecting module performance. Each of the 60 modules in the Flight Mirror Assembly (FMA) supports 200–300 densely packed 0.4 mm thick glass mirror segments in order to meet the unprecedented effective area required to achieve the scientific objectives of the mission. Detailed Finite Element Analysis (FEA), materials testing, and environmental testing have been completed to ensure the modules can be successfully launched. Resulting stress margins are positive based on detailed FEA, a large factor of safety, and a design strength determined by robust characterization of the glass properties. FEA correlates well with the results of the successful modal, vibration, and acoustic environmental tests. Deformation of the module due to on-orbit thermal conditions is also a major design driver. A preliminary thermal control system has been designed and the sensitivity of module optical performance to various thermal loads has been determined using optomechanical analysis methods developed for this unique assembly. This design and analysis furthers the goal of building a module that demonstrates the ability to meet IXO requirements, which is the current focus of IXO FMA technology development team.
{"title":"Design and analysis of the International X-Ray Observatory mirror modules","authors":"R. Mcclelland, T. Carnahan","doi":"10.1117/12.857535","DOIUrl":"https://doi.org/10.1117/12.857535","url":null,"abstract":"The Soft X-Ray Telescope (SXT) modules are the fundamental focusing assemblies on NASA's next major X-ray telescope mission, the International X-Ray Observatory (IXO). {su12]The preliminary design and analysis of these assemblies has been completed, addressing the major engineering challenges and leading to an understanding of the factors effecting module performance. Each of the 60 modules in the Flight Mirror Assembly (FMA) supports 200–300 densely packed 0.4 mm thick glass mirror segments in order to meet the unprecedented effective area required to achieve the scientific objectives of the mission. Detailed Finite Element Analysis (FEA), materials testing, and environmental testing have been completed to ensure the modules can be successfully launched. Resulting stress margins are positive based on detailed FEA, a large factor of safety, and a design strength determined by robust characterization of the glass properties. FEA correlates well with the results of the successful modal, vibration, and acoustic environmental tests. Deformation of the module due to on-orbit thermal conditions is also a major design driver. A preliminary thermal control system has been designed and the sensitivity of module optical performance to various thermal loads has been determined using optomechanical analysis methods developed for this unique assembly. This design and analysis furthers the goal of building a module that demonstrates the ability to meet IXO requirements, which is the current focus of IXO FMA technology development team.","PeriodicalId":378029,"journal":{"name":"2010 IEEE Aerospace Conference","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128021923","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 : 2010-03-06DOI: 10.1109/AERO.2010.5446950
Sara C. Spangelo, D. Boone, J. Cutler
We introduce models and tools to assess the communication capacity of dynamic ground station networks, in particular federated networks that are composed of geographically diverse and independent stations that loosely collaborate to provide increased satellite connectivity. Network capacity is the amount of information exchanged between a network of satellites and ground stations. The constraints on total network capacity which influence transmission capabilities are outlined, such as the satellite, ground station, and overall network parameters. Orbit propagators are combined with engineering analysis software to compare the capacity of existing and future ground station networks. Simulation results from recent clustered satellite launches are presented and discussed. By studying network capacity, we identify the potential for leveraging these federated networks to support multiple missions from multiple institutions. Future work is outlined, including the need to accurately model both satellite communication requirements, develop real time network analysis tools, and work towards developing dynamic optimization techinques for global autonomous networks.
{"title":"Assessing the capacity of a federated ground station","authors":"Sara C. Spangelo, D. Boone, J. Cutler","doi":"10.1109/AERO.2010.5446950","DOIUrl":"https://doi.org/10.1109/AERO.2010.5446950","url":null,"abstract":"We introduce models and tools to assess the communication capacity of dynamic ground station networks, in particular federated networks that are composed of geographically diverse and independent stations that loosely collaborate to provide increased satellite connectivity. Network capacity is the amount of information exchanged between a network of satellites and ground stations. The constraints on total network capacity which influence transmission capabilities are outlined, such as the satellite, ground station, and overall network parameters. Orbit propagators are combined with engineering analysis software to compare the capacity of existing and future ground station networks. Simulation results from recent clustered satellite launches are presented and discussed. By studying network capacity, we identify the potential for leveraging these federated networks to support multiple missions from multiple institutions. Future work is outlined, including the need to accurately model both satellite communication requirements, develop real time network analysis tools, and work towards developing dynamic optimization techinques for global autonomous networks.","PeriodicalId":378029,"journal":{"name":"2010 IEEE Aerospace Conference","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115545099","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 : 2010-03-06DOI: 10.1109/AERO.2010.5446707
Russel P. Kauffman, P. North, P. M. Fuller
Radiance restoration via linear filtering is problematic for small targets, and estimating the thermally emitted radiance of sub-pixel targets is very difficult, resulting in large errors. However, with a priori knowledge of the geometry of a scene, a site model can be constructed to aid in radiance estimation. The scene is modeled as a linear combination of known shapes and the radiance of these shapes is adjusted to fit the observed image. This method of estimating the radiances of small to sub-pixel targets can yield significantly lower errors than linear filtering. The performance of the method on synthetic images is discussed as a function of the size, radiance, and background of the target and of the noise in the image. The model-based approach is found to outperform a simple linear filter for very small targets (diameter of a few pixels) with high contrast relative to the image noise.1 2
{"title":"Model-based radiometric restoration","authors":"Russel P. Kauffman, P. North, P. M. Fuller","doi":"10.1109/AERO.2010.5446707","DOIUrl":"https://doi.org/10.1109/AERO.2010.5446707","url":null,"abstract":"Radiance restoration via linear filtering is problematic for small targets, and estimating the thermally emitted radiance of sub-pixel targets is very difficult, resulting in large errors. However, with a priori knowledge of the geometry of a scene, a site model can be constructed to aid in radiance estimation. The scene is modeled as a linear combination of known shapes and the radiance of these shapes is adjusted to fit the observed image. This method of estimating the radiances of small to sub-pixel targets can yield significantly lower errors than linear filtering. The performance of the method on synthetic images is discussed as a function of the size, radiance, and background of the target and of the noise in the image. The model-based approach is found to outperform a simple linear filter for very small targets (diameter of a few pixels) with high contrast relative to the image noise.1 2","PeriodicalId":378029,"journal":{"name":"2010 IEEE Aerospace Conference","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115678898","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 : 2010-03-06DOI: 10.1109/AERO.2010.5446826
A. Kodali, K. Pattipati, Satnam Singh
In this paper, we formulate a coupled factorial hidden Markov model-based framework to diagnose dependent faults occurring over time. In our previous research [1][2], the problem of diagnosing dynamic multiple faults (DMFD) is solved by assuming that the faults are independent. Here, we extend this formulation to determine the most likely evolution of dependent fault states (NP-hard problem), the one that best explains the observed test outcomes over time. An iterative Gauss-Seidel coordinate ascent optimization method along with the coupling assumptions (mixed memory Markov model) is proposed for solving the dynamic coupled fault diagnosis (DCFD) problem. A soft Viterbi algorithm is also implemented within the framework for decoding dependent fault states over time. We demonstrate the algorithm on small-scale and real-world systems and the simulation results show that this approach improves the correct isolation rate as compared to the formulation with independent fault states (DMFD).12
{"title":"A coupled factorial hidden Markov model (CFHMM) for diagnosing coupled faults","authors":"A. Kodali, K. Pattipati, Satnam Singh","doi":"10.1109/AERO.2010.5446826","DOIUrl":"https://doi.org/10.1109/AERO.2010.5446826","url":null,"abstract":"In this paper, we formulate a coupled factorial hidden Markov model-based framework to diagnose dependent faults occurring over time. In our previous research [1][2], the problem of diagnosing dynamic multiple faults (DMFD) is solved by assuming that the faults are independent. Here, we extend this formulation to determine the most likely evolution of dependent fault states (NP-hard problem), the one that best explains the observed test outcomes over time. An iterative Gauss-Seidel coordinate ascent optimization method along with the coupling assumptions (mixed memory Markov model) is proposed for solving the dynamic coupled fault diagnosis (DCFD) problem. A soft Viterbi algorithm is also implemented within the framework for decoding dependent fault states over time. We demonstrate the algorithm on small-scale and real-world systems and the simulation results show that this approach improves the correct isolation rate as compared to the formulation with independent fault states (DMFD).12","PeriodicalId":378029,"journal":{"name":"2010 IEEE Aerospace Conference","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116191465","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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