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Sample records for andreas fault system

  1. Tectonic history of the north portion of the San Andreas fault system, California, inferred from gravity and magnetic anomalies

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    Griscom, A.; Jachens, R.C.

    1989-01-01

    Geologic and geophysical data for the San Andreas fault system north of San Francisco suggest that the eastern boundary of the Pacific plate migrated eastward from its presumed original position at the base of the continental slope to its present position along the San Andreas transform fault by means of a series of eastward jumps of the Mendocino triple junction. These eastward jumps total a distance of about 150 km since 29 Ma. Correlation of right-laterally displaced gravity and magnetic anomalies that now have components at San Francisco and on the shelf north of Point Arena indicates that the presently active strand of the San Andreas fault north of the San Francisco peninsula formed recently at about 5 Ma when the triple junction jumped eastward a minimum of 100 km to its present location at the north end of the San Andreas fault. -from Authors

  2. Response of deformation patterns to reorganizations of the southern San Andreas fault system since ca. 1.5 Ma

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    Cooke, M. L.; Fattaruso, L.; Dorsey, R. J.; Housen, B. A.

    2015-12-01

    Between ~1.5 and 1.1 Ma, the southern San Andreas fault system underwent a major reorganization that included initiation of the San Jacinto fault and termination of slip on the extensional West Salton detachment fault. The southern San Andreas fault itself has also evolved since this time, with several shifts in activity among fault strands within San Gorgonio Pass. We use three-dimensional mechanical Boundary Element Method models to investigate the impact of these changes to the fault network on deformation patterns. A series of snapshot models of the succession of active fault geometries explore the role of fault interaction and tectonic loading in abandonment of the West Salton detachment fault, initiation of the San Jacinto fault, and shifts in activity of the San Andreas fault. Interpreted changes to uplift patterns are well matched by model results. These results support the idea that growth of the San Jacinto fault led to increased uplift rates in the San Gabriel Mountains and decreased uplift rates in the San Bernardino Mountains. Comparison of model results for vertical axis rotation to data from paleomagnetic studies reveals a good match to local rotation patterns in the Mecca Hills and Borrego Badlands. We explore the mechanical efficiency at each step in the evolution, and find an overall trend toward increased efficiency through time. Strain energy density patterns are used to identify regions of off-fault deformation and potential incipient faulting. These patterns support the notion of north-to-south propagation of the San Jacinto fault during its initiation. The results of the present-day model are compared with microseismicity focal mechanisms to provide additional insight into the patterns of off-fault deformation within the southern San Andreas fault system.

  3. The San Andreas Fault 'Supersite' (Invited)

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    Hudnut, K. W.

    2013-12-01

    An expanded and permanent Supersite has been proposed to the Committee on Earth Observation Satellites (CEOS) for the San Andreas Fault system, based upon the successful initial Group on Earth Observations (GEO) Geohazard Supersite for the Los Angeles region from 2009-2013. As justification for the comprehensive San Andreas Supersite, consider the earthquake history of California, in particular the devastating M 7.8 San Francisco earthquake of 1906, which occurred along the San Andreas Fault, as did an earthquake of similar magnitude in 1857 in southern California. Los Angeles was only a small town then, but now the risk exposure has increased for both of California's megacities. Between the San Francisco and Los Angeles urban areas lies a section of the San Andreas Fault known to creep continually, so it has relatively less earthquake hazard. It used to be thought of as capable of stopping earthquakes entering it from either direction. Transitional behavior at either end of the creeping section is known to display a full range of seismic to aseismic slip events and accompanying seismicity and strain transient events. Because the occurrence of creep events is well documented by instrumental networks such as CISN and PBO, the San Andreas Supersite can be expected to be especially effective. A good baseline level of geodetic data regarding past events and strain accumulation and release exists. Many prior publications regarding the occurrence of geophysical phenomena along the San Andreas Fault system mean that in order to make novel contributions, state-of-the-art science will be required within this Supersite region. In more recent years, the 1989 Loma Prieta earthquake struck adjacent to the San Andreas Fault and caused the most damage along the western side of the San Francisco Bay Area. More recently, the concern has focused on the potential for future events along the Hayward Fault along the eastern side of San Francisco Bay. In Southern California, earthquakes

  4. Aseismic Slip Events along the Southern San Andreas Fault System Captured by Radar Interferometry

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    Vincent, P

    2001-10-01

    A seismic slip is observed along several faults in the Salton Sea and southernmost Landers rupture zone regions using interferometric synthetic aperture radar (InSAR) data spanning different time periods between 1992 and 1997. In the southernmost Landers rupture zone, projecting south from the Pinto Mountain Fault, sharp discontinuities in the interferometric phase are observed along the sub-parallel Burnt Mountain and Eureka Peak Faults beginning three months after the Landers earthquake and is interpreted to be post-Landers after-slip. Abrupt phase offsets are also seen along the two southernmost contiguous 11 km Durmid Hill and North Shore segments of the San Andreas Fault with an abrupt termination of slip near the northern end of the North Shore Segment. A sharp phase offset is seen across 20 km of the 30 km-long Superstition Hills Fault before phase decorrelation in the Imperial Valley along the southern 10 km of the fault prevents coherent imaging by InSAR. A time series of deformation interferograms suggest most of this slip occurred between 1993 and 1995 and none of it occurred between 1992 and 1993. A phase offset is also seen along a 5 km central segment of the Coyote Creek fault that forms a wedge with an adjoining northeast-southwest trending conjugate fault. Most of the slip observed on the southern San Andreas and Superstition Hills Faults occurred between 1993 and 1995--no slip is observed in the 92-93 interferograms. These slip events, especially the Burnt Mountain and Eureka Peak events, are inferred to be related to stress redistribution from the June, 1992 M{sub w} = 7.3 Landers earthquake. Best-fit elastic models of the San Andreas and Superstition Hills slip events suggest source mechanisms with seismic moments over three orders of magnitude larger than a maximum possible summation of seismic moments from all seismicity along each fault segment during the entire 4.8-year time interval spanned by the InSAR data. Aseismic moment releases of this

  5. 4-D Strain Rate Along the San Andreas Fault System: Knowns and Unknowns (Invited)

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    Sandwell, D. T.; Smith-Konter, B. R.; Tong, X.

    2013-12-01

    Geodetic imaging of the San Andreas Fault System from a combination of GPS and InSAR techniques is providing a remarkably accurate and detailed mapping of plate boundary surface strain rate. We have assembled and compared strain-rate models from 17 research groups and find that 5 of these models provide remarkably similar images of the surface strain rate tensor, having principal strain axes in good agreement with the principal stress directions inferred from a recent compilation of earthquake focal mechanisms [Yang and Hauksson, 2013]. While surface strain rates seem to be well mapped, it is also important to understand strain rate variations with depth and through time. We have developed a kinematic 4-D earthquake cycle model spanning the North American-Pacific plate boundary that simulates interseismic strain accumulation, coseismic displacement, and postseismic viscous relaxation of the mantle. The model can predict the full 4-D strain rate tensor for the past 1000 years but relies on numerous approximations and assumptions. This talk will highlight the most poorly known aspects of the 4-D model and discuss additional measurements that could improve our mapping of the 4-D strain rate.

  6. GPS-aided inertial technology and navigation-based photogrammetry for aerial mapping the San Andreas fault system

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    Sanchez, Richard D.; Hudnut, Kenneth W.

    2004-01-01

    Aerial mapping of the San Andreas Fault System can be realized more efficiently and rapidly without ground control and conventional aerotriangulation. This is achieved by the direct geopositioning of the exterior orientation of a digital imaging sensor by use of an integrated Global Positioning System (GPS) receiver and an Inertial Navigation System (INS). A crucial issue to this particular type of aerial mapping is the accuracy, scale, consistency, and speed achievable by such a system. To address these questions, an Applanix Digital Sensor System (DSS) was used to examine its potential for near real-time mapping. Large segments of vegetation along the San Andreas and Cucamonga faults near the foothills of the San Bernardino and San Gabriel Mountains were burned to the ground in the California wildfires of October-November 2003. A 175 km corridor through what once was a thickly vegetated and hidden fault surface was chosen for this study. Both faults pose a major hazard to the greater Los Angeles metropolitan area and a near real-time mapping system could provide information vital to a post-disaster response.

  7. Retardations in fault creep rates before local moderate earthquakes along the San Andreas fault system, central California

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    Burford, R.O.

    1988-01-01

    Records of shallow aseismic slip (fault creep) obtained along parts of the San Andreas and Calaveras faults in central California demonstrate that significant changes in creep rates often have been associated with local moderate earthquakes. An immediate postearthquake increase followed by gradual, long-term decay back to a previous background rate is generally the most obvious earthquake effect on fault creep. This phenomenon, identified as aseismic afterslip, usually is characterized by above-average creep rates for several months to a few years. In several cases, minor step-like movements, called coseismic slip events, have occurred at or near the times of mainshocks. One extreme case of coseismic slip, recorded at Cienega Winery on the San Andreas fault 17.5 km southeast of San Juan Bautista, consisted of 11 mm of sudden displacement coincident with earthquakes of ML=5.3 and ML=5.2 that occurred 2.5 minutes apart on 9 April 1961. At least one of these shocks originated on the main fault beneath the winery. Creep activity subsequently stopped at the winery for 19 months, then gradually returned to a nearly steady rate slightly below the previous long-term average. The phenomena mentioned above can be explained in terms of simple models consisting of relatively weak material along shallow reaches of the fault responding to changes in load imposed by sudden slip within the underlying seismogenic zone. In addition to coseismic slip and afterslip phenomena, however, pre-earthquake retardations in creep rates also have been observed. Onsets of significant, persistent decreases in creep rates have occurred at several sites 12 months or more before the times of moderate earthquakes. A 44-month retardation before the 1979 ML=5.9 Coyote Lake earthquake on the Calaveras fault was recorded at the Shore Road creepmeter site 10 km northwest of Hollister. Creep retardation on the San Andreas fault near San Juan Bautista has been evident in records from one creepmeter site for

  8. SAFOD Penetrates the San Andreas Fault

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    Mark D. Zoback

    2006-03-01

    Full Text Available SAFOD, the San Andreas Fault Observatory at Depth (Fig. 1, completed an important milestone in July 2005 by drilling through the San Andreas Fault at seismogenic depth. SAFOD is one of three major components of EarthScope, a U.S. National Science Foundation (NSF initiative being conducted in collaboration with the U.S. Geological Survey (USGS. The International Continental Scientific DrillingProgram (ICDP provides engineering and technical support for the project as well as online access to project data and information (http://www.icdp-online.de/sites/sanandreas/news/news1.html. In 2002, the ICDP, the NSF, and the USGS provided funding for a pilot hole project at the SAFOD site. Twenty scientifi c papers summarizing the results of the pilot hole project as well as pre-SAFOD site characterization studies were published in Geophysical Research Letters (Vol.31, Nos. 12 and 15, 2004.

  9. Synthetic seismicity for the San Andreas fault

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    S. N. Ward

    1994-06-01

    Full Text Available Because historical catalogs generally span only a few repetition intervals of major earthquakes, they do not provide much constraint on how regularly earthquakes recur. In order to obtain better recurrence statistics and long-term probability estimates for events M ? 6 on the San Andreas fault, we apply a seismicity model to this fault. The model is based on the concept of fault segmentation and the physics of static dislocations which allow for stress transfer between segments. Constraints are provided by geological and seismological observations of segment lengths, characteristic magnitudes and long-term slip rates. Segment parameters slightly modified from the Working Group on California Earthquake Probabilities allow us to reproduce observed seismicity over four orders of magnitude. The model yields quite irregular earthquake recurrence patterns. Only the largest events (M ? 7.5 are quasi-periodic; small events cluster. Both the average recurrence time and the aperiodicity are also a function of position along the fault. The model results are consistent with paleoseismic data for the San Andreas fault as well as a global set of historical and paleoseismic recurrence data. Thus irregular earthquake recurrence resulting from segment interaction is consistent with a large range of observations.

  10. Observing the San Andreas Fault at Depth

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    Ellsworth, W.; Hickman, S.; Zoback, M.; Davis, E.; Gee, L.; Huggins, R.; Krug, R.; Lippus, C.; Malin, P.; Neuhauser, D.; Paulsson, B.; Shalev, E.; Vajapeyam, B.; Weiland, C.; Zumberge, M.

    2005-12-01

    Extending 4 km into the Earth along a diagonal path that crosses the divide between Salinian basement accreted to the Pacific Plate and Cretaceous sediments of North America, the main hole at the San Andreas Fault Observatory at Depth (SAFOD) was designed to provide a portal into the inner workings of a major plate boundary fault. The successful drilling and casing of the main hole in the summer of 2005 to a total vertical depth of 3.1 km make it possible to conduct spatially extensive and long-duration observations of active tectonic processes within the actively deforming core of the San Andreas Fault. In brief, the observatory consists of retrievable seismic, deformation and environmental sensors deployed inside the casing in both the main hole (maximum temperature 135 C) and the collocated pilot hole (1.1 km depth), and a fiber optic strainmeter installed behind casing in the main hole. By using retrievable systems deployed on either wire line or rigid tubing, each hole can be used for a wide range of scientific purposes, with instrumentation that takes maximum advantage of advances in sensor technology. To meet the scientific and technical challenges of building the observatory, borehole instrumentation systems developed for use in the petroleum industry and by the academic community in other deep research boreholes have been deployed in the SAFOD pilot hole and main hole over the past year. These systems included 15Hz omni-directional and 4.5 Hz gimbaled seismometers, micro-electro-mechanical accelerometers, tiltmeters, sigma-delta digitizers, and a fiber optic interferometeric strainmeter. A 1200-m-long, 3-component 80-level clamped seismic array was also operated in the main hole for 2 weeks of recording in May of 2005, collecting continuous seismic data at 4000 sps. Some of the observational highlights include capturing one of the M 2 SAFOD target repeating earthquakes in the near-field at a distance of 420 m, with accelerations of up to 200 cm/s and a

  11. Deep-water turbidites as Holocene earthquake proxies: the Cascadia subduction zone and Northern San Andreas Fault systems

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    J. E. Johnson

    2003-06-01

    Full Text Available New stratigraphic evidence from the Cascadia margin demonstrates that 13 earthquakes ruptured the margin from Vancouver Island to at least the California border following the catastrophic eruption of Mount Mazama. These 13 events have occurred with an average repeat time of ?? 600 years since the first post-Mazama event ?? 7500 years ago. The youngest event ?? 300 years ago probably coincides with widespread evidence of coastal subsidence and tsunami inundation in buried marshes along the Cascadia coast. We can extend the Holocene record to at least 9850 years, during which 18 events correlate along the same region. The pattern of repeat times is consistent with the pattern observed at most (but not all localities onshore, strengthening the contention that both were produced by plate-wide earthquakes. We also observe that the sequence of Holocene events in Cascadia may contain a repeating pattern, a tantalizing look at what may be the long-term behavior of a major fault system. Over the last ?? 7500 years, the pattern appears to have repeated at least three times, with the most recent A.D. 1700 event being the third of three events following a long interval of 845 years between events T4 and T5. This long interval is one that is also recognized in many of the coastal records, and may serve as an anchor point between the offshore and onshore records. Similar stratigraphic records are found in two piston cores and one box core from Noyo Channel, adjacent to the Northern San Andreas Fault, which show a cyclic record of turbidite beds, with thirty- one turbidite beds above a Holocene/.Pleistocene faunal «datum». Thus far, we have determined ages for 20 events including the uppermost 5 events from these cores. The uppermost event returns a «modern» age, which we interpret is likely the 1906 San Andreas earthquake. The penultimate event returns an intercept age of A.D. 1664 (2 ?? range 1505- 1822. The third event and fourth event

  12. Chemical controls on fault behavior: weakening of serpentinite sheared against quartz-bearing rocks and its significance for fault creep in the San Andreas system

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    Moore, Diane E.; Lockner, David A.

    2013-01-01

    The serpentinized ultramafic rocks found in many plate-tectonic settings commonly are juxtaposed against crustal rocks along faults, and the chemical contrast between the rock types potentially could influence the mechanical behavior of such faults. To investigate this possibility, we conducted triaxial experiments under hydrothermal conditions (200-350°C), shearing serpentinite gouge between forcing blocks of granite or quartzite. In an ultramafic chemical environment, the coefficient of friction, µ, of lizardite and antigorite serpentinite is 0.5-0.6, and µ increases with increasing temperature over the tested range. However, when either lizardite or antigorite serpentinite is sheared against granite or quartzite, strength is reduced to µ ~ 0.3, with the greatest strength reductions at the highest temperatures (temperature weakening) and slowest shearing rates (velocity strengthening). The weakening is attributed to a solution-transfer process that is promoted by the enhanced solubility of serpentine in pore fluids whose chemistry has been modified by interaction with the quartzose wall rocks. The operation of this process will promote aseismic slip (creep) along serpentinite-bearing crustal faults at otherwise seismogenic depths. During short-term experiments serpentine minerals reprecipitate in low-stress areas, whereas in longer experiments new Mg-rich phyllosilicates crystallize in response to metasomatic exchanges across the serpentinite-crustal rock contact. Long-term shear of serpentinite against crustal rocks will cause the metasomatic mineral assemblages, which may include extremely weak minerals such as saponite or talc, to play an increasingly important role in the mechanical behavior of the fault. Our results may explain the distribution of creep on faults in the San Andreas system.

  13. Using surface creep rate to infer fraction locked for sections of the San Andreas fault system in northern California from alignment array and GPS data

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    Lienkaemper, James J.; McFarland, Forrest S.; Simpson, Robert W.; Caskey, S. John

    2014-01-01

    Surface creep rate, observed along five branches of the dextral San Andreas fault system in northern California, varies considerably from one section to the next, indicating that so too may the depth at which the faults are locked. We model locking on 29 fault sections using each section’s mean long‐term creep rate and the consensus values of fault width and geologic slip rate. Surface creep rate observations from 111 short‐range alignment and trilateration arrays and 48 near‐fault, Global Positioning System station pairs are used to estimate depth of creep, assuming an elastic half‐space model and adjusting depth of creep iteratively by trial and error to match the creep observations along fault sections. Fault sections are delineated either by geometric discontinuities between them or by distinctly different creeping behaviors. We remove transient rate changes associated with five large (M≥5.5) regional earthquakes. Estimates of fraction locked, the ratio of moment accumulation rate to loading rate, on each section of the fault system provide a uniform means to inform source parameters relevant to seismic‐hazard assessment. From its mean creep rates, we infer the main branch (the San Andreas fault) ranges from only 20%±10% locked on its central creeping section to 99%–100% on the north coast. From mean accumulation rates, we infer that four urban faults appear to have accumulated enough seismic moment to produce major earthquakes: the northern Calaveras (M 6.8), Hayward (M 6.8), Rodgers Creek (M 7.1), and Green Valley (M 7.1). The latter three faults are nearing or past their mean recurrence interval.

  14. Continuation of the San Andreas fault system into the upper mantle: Evidence from spinel peridotite xenoliths in the Coyote Lake basalt, central California

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    Titus, Sarah J.; Medaris, L. Gordon; Wang, Herbert F.; Tikoff, Basil

    2007-01-01

    The Coyote Lake basalt, located near the intersection of the Hayward and Calaveras faults in central California, contains spinel peridotite xenoliths from the mantle beneath the San Andreas fault system. Six upper mantle xenoliths were studied in detail by a combination of petrologic techniques. Temperature estimates, obtained from three two-pyroxene geothermometers and the Al-in-orthopyroxene geothermometer, indicate that the xenoliths equilibrated at 970-1100 °C. A thermal model was used to estimate the corresponding depth of equilibration for these xenoliths, resulting in depths between 38 and 43 km. The lattice preferred orientation of olivine measured in five of the xenolith samples show strong point distributions of olivine crystallographic axes suggesting that fabrics formed under high-temperature conditions. Calculated seismic anisotropy values indicate an average shear wave anisotropy of 6%, higher than the anisotropy calculated from xenoliths from other tectonic environments. Using this value, the anisotropic layer responsible for fault-parallel shear wave splitting in central California is less than 100 km thick. The strong fabric preserved in the xenoliths suggests that a mantle shear zone exists below the Calaveras fault to a depth of at least 40 km, and combining xenolith petrofabrics with shear wave splitting studies helps distinguish between different models for deformation at depth beneath the San Andrea fault system.

  15. Isotopic evidence for the infiltration of mantle and metamorphic CO2-H2O fluids from below in faulted rocks from the San Andreas Fault System

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    Pili, E.; Kennedy, B.M.; Conrad, M.E.; Gratier, J.-P.

    2010-12-15

    To characterize the origin of the fluids involved in the San Andreas Fault (SAF) system, we carried out an isotope study of exhumed faulted rocks from deformation zones, vein fillings and their hosts and the fluid inclusions associated with these materials. Samples were collected from segments along the SAF system selected to provide a depth profile from upper to lower crust. In all, 75 samples from various structures and lithologies from 13 localities were analyzed for noble gas, carbon, and oxygen isotope compositions. Fluid inclusions exhibit helium isotope ratios ({sup 3}He/{sup 4}He) of 0.1-2.5 times the ratio in air, indicating that past fluids percolating through the SAF system contained mantle helium contributions of at least 35%, similar to what has been measured in present-day ground waters associated with the fault (Kennedy et al., 1997). Calcite is the predominant vein mineral and is a common accessory mineral in deformation zones. A systematic variation of C- and O-isotope compositions of carbonates from veins, deformation zones and their hosts suggests percolation by external fluids of similar compositions and origin with the amount of fluid infiltration increasing from host rocks to vein to deformation zones. The isotopic trend observed for carbonates in veins and deformation zones follows that shown by carbonates in host limestones, marbles, and other host rocks, increasing with increasing contribution of deep metamorphic crustal volatiles. At each crustal level, the composition of the infiltrating fluids is thus buffered by deeper metamorphic sources. A negative correlation between calcite {delta}{sup 13}C and fluid inclusion {sup 3}He/{sup 4}He is consistent with a mantle origin for a fraction of the infiltrating CO{sub 2}. Noble gas and stable isotope systematics show consistent evidence for the involvement of mantle-derived fluids combined with infiltration of deep metamorphic H{sub 2}O and CO{sub 2} in faulting, supporting the involvement of

  16. Geomorphic evidence of active tectonics in the San Gorgonio Pass region of the San Andreas Fault system: an example of discovery-based research in undergraduate teaching

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    Reinen, L. A.; Yule, J. D.

    2014-12-01

    Student-conducted research in courses during the first two undergraduate years can increase learning and improve student self-confidence in scientific study, and is recommended for engaging and retaining students in STEM fields (PCAST, 2012). At Pomona College, incorporating student research throughout the geology curriculum tripled the number of students conducting research prior to their senior year that culminated in a professional conference presentation (Reinen et al., 2006). Here we present an example of discovery-based research in Neotectonics, a second-tier course predominantly enrolling first-and second-year students; describe the steps involved in the four week project; and discuss early outcomes of student confidence, engagement and retention. In the San Gorgonio Pass region (SGPR) in southern California, the San Andreas fault undergoes a transition from predominantly strike-slip to a complex system of faults with significant dip-slip, resulting in diffuse deformation and raising the question of whether a large earthquake on the San Andreas could propagate through the region (Yule, 2009). In spring 2014, seven students in the Neotectonics course conducted original research investigating quantifiable geomorphic evidence of tectonic activity in the SGPR. Students addressed questions of [1] unequal uplift in the San Bernardino Mountains, [2] fault activity indicated by stream knick points, [3] the role of fault style on mountain front sinuosity, and [4] characteristic earthquake slip determined via fault scarp degradation models. Students developed and revised individual projects, collaborated with each other on methods, and presented results in a public forum. A final class day was spent reviewing the projects and planning future research directions. Pre- and post-course surveys show increases in students' self-confidence in the design, implementation, and presentation of original scientific inquiries. 5 of 6 eligible students participated in research the

  17. Vertical deformation along the Indio Hills, San Andreas Fault, California

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    Scharer, K. M.; Blisniuk, K.; Sharp, W. D.; Williams, P. L.; Johnson, K.

    2014-12-01

    Halfway between the Salton Sea and San Gorgonio Pass, the southernmost San Andreas Fault (SAF) bifurcates into the Mission Creek and Banning strands. These strands bound the Indio Hills (IH), and mark the first of a series of left-stepping branches that define the transpressional, southern Big Bend of the SAF. Between the fault strands, the Quaternary Ocotillo Formation is deformed with fold axis orientations consistent with dextral shear; structurally the IH are synclinal in the east, transitioning to a complex antiform with increased uplift suggested by exhumation of Tertiary units in the west. We report new long- and short-term erosion rates across the IH and uplift rates on the Banning strand, and we evaluate these measurements in terms of slip rates across the fault system and structural deformation within the IH. Two methods of catchment-averaged erosion rates provide minimum rates yield similar results, (0.08 to 0.34 mm/yr) across 6 catchments. The long-term rates are calculated from eroded volumes estimated from a 10-m DEM surface enveloping the Indio Hills and assume that all folding and uplift initiated ca. 500ka (the 750 ka Bishop ash is uplifted and warped within the IH). The short-term rates, determined from 10Be dating of alluvial sediments, increase gradually to the northwest. Similarity of the rates suggests steady state uplift over the history of the fold; ongoing structural analysis and dating needed to constrain the maximum rates will test this possibility. The new uplift rate for the Banning strand at the east end of the IH is determined from a 60 pts/m^2 DEM produced by structure from motion photogrammetry and U-series ages and cosmogenic dates that provide an age range of 20-76ka for a fan vertically offset by ~2.5 m. The resulting uplift rate on the fault (0.03-0.125 mm/yr) overlaps with the short-term catchment-averaged erosion rate for this location (0.08 mm/yr). Consequently, we interpret that vertical strain is partitioned onto both the

  18. Zoogeography of the San Andreas Fault system: Great Pacific Fracture Zones correspond with spatially concordant phylogeographic boundaries in western North America.

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    Gottscho, Andrew D

    2016-02-01

    The purpose of this article is to provide an ultimate tectonic explanation for several well-studied zoogeographic boundaries along the west coast of North America, specifically, along the boundary of the North American and Pacific plates (the San Andreas Fault system). By reviewing 177 references from the plate tectonics and zoogeography literature, I demonstrate that four Great Pacific Fracture Zones (GPFZs) in the Pacific plate correspond with distributional limits and spatially concordant phylogeographic breaks for a wide variety of marine and terrestrial animals, including invertebrates, fish, amphibians, reptiles, birds, and mammals. These boundaries are: (1) Cape Mendocino and the North Coast Divide, (2) Point Conception and the Transverse Ranges, (3) Punta Eugenia and the Vizcaíno Desert, and (4) Cabo Corrientes and the Sierra Transvolcanica. However, discussion of the GPFZs is mostly absent from the zoogeography and phylogeography literature likely due to a disconnect between biologists and geologists. I argue that the four zoogeographic boundaries reviewed here ultimately originated via the same geological process (triple junction evolution). Finally, I suggest how a comparative phylogeographic approach can be used to test the hypothesis presented here. PMID:25521005

  19. Deep permeability of the San Andreas Fault from San Andreas Fault Observatory at Depth (SAFOD) core samples

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    Morrow, Carolyn A.; Lockner, David A.; Moore, Diane E.; Hickman, Stephen H.

    2014-01-01

    The San Andreas Fault Observatory at Depth (SAFOD) scientific borehole near Parkfield, California crosses two actively creeping shear zones at a depth of 2.7 km. Core samples retrieved from these active strands consist of a foliated, Mg-clay-rich gouge containing porphyroclasts of serpentinite and sedimentary rock. The adjacent damage zone and country rocks are comprised of variably deformed, fine-grained sandstones, siltstones, and mudstones. We conducted laboratory tests to measure the permeability of representative samples from each structural unit at effective confining pressures, Pe up to the maximum estimated in situ Pe of 120 MPa. Permeability values of intact samples adjacent to the creeping strands ranged from 10−18 to 10−21 m2 at Pe = 10 MPa and decreased with applied confining pressure to 10−20–10−22 m2 at 120 MPa. Values for intact foliated gouge samples (10−21–6 × 10−23 m2 over the same pressure range) were distinctly lower than those for the surrounding rocks due to their fine-grained, clay-rich character. Permeability of both intact and crushed-and-sieved foliated gouge measured during shearing at Pe ≥ 70 MPa ranged from 2 to 4 × 10−22 m2 in the direction perpendicular to shearing and was largely insensitive to shear displacement out to a maximum displacement of 10 mm. The weak, actively-deforming foliated gouge zones have ultra-low permeability, making the active strands of the San Andreas Fault effective barriers to cross-fault fluid flow. The low matrix permeability of the San Andreas Fault creeping zones and adjacent rock combined with observations of abundant fractures in the core over a range of scales suggests that fluid flow outside of the actively-deforming gouge zones is probably fracture dominated.

  20. Correlation between deep fluids, tremor and creep along the central San Andreas fault

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    Becken, M.; Ritter, O.; Bedrosian, P.A.; Weckmann, U.

    2011-01-01

    The seismicity pattern along the San Andreas fault near Parkfield and Cholame, California, varies distinctly over a length of only fifty kilometres. Within the brittle crust, the presence of frictionally weak minerals, fault-weakening high fluid pressures and chemical weakening are considered possible causes of an anomalously weak fault northwest of Parkfield. Non-volcanic tremor from lower-crustal and upper-mantle depths is most pronounced about thirty kilometres southeast of Parkfield and is thought to be associated with high pore-fluid pressures at depth. Here we present geophysical evidence of fluids migrating into the creeping section of the San Andreas fault that seem to originate in the region of the uppermost mantle that also stimulates tremor, and evidence that along-strike variations in tremor activity and amplitude are related to strength variations in the lower crust and upper mantle. Interconnected fluids can explain a deep zone of anomalously low electrical resistivity that has been imaged by magnetotelluric data southwest of the Parkfield-Cholame segment. Near Cholame, where fluids seem to be trapped below a high-resistivity cap, tremor concentrates adjacent to the inferred fluids within a mechanically strong zone of high resistivity. By contrast, subvertical zones of low resistivity breach the entire crust near the drill hole of the San Andreas Fault Observatory at Depth, northwest of Parkfield, and imply pathways for deep fluids into the eastern fault block, coincident with a mechanically weak crust and the lower tremor amplitudes in the lower crust. Fluid influx to the fault system is consistent with hypotheses of fault-weakening high fluid pressures in the brittle crust. ?? 2011 Macmillan Publishers Limited. All rights reserved.

  1. Frictional strength and heat flow of southern San Andreas Fault

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    Zhu, P. P.

    2016-01-01

    Frictional strength and heat flow of faults are two related subjects in geophysics and seismology. To date, the investigation on regional frictional strength and heat flow still stays at the stage of qualitative estimation. This paper is concentrated on the regional frictional strength and heat flow of the southern San Andreas Fault (SAF). Based on the in situ borehole measured stress data, using the method of 3D dynamic faulting analysis, we quantitatively determine the regional normal stress, shear stress, and friction coefficient at various seismogenic depths. These new data indicate that the southern SAF is a weak fault within the depth of 15 km. As depth increases, all the regional normal and shear stresses and friction coefficient increase. The former two increase faster than the latter. Regional shear stress increment per kilometer equals 5.75 ± 0.05 MPa/km for depth ≤15 km; regional normal stress increment per kilometer is equal to 25.3 ± 0.1 MPa/km for depth ≤15 km. As depth increases, regional friction coefficient increment per kilometer decreases rapidly from 0.08 to 0.01/km at depths less than ~3 km. As depth increases from ~3 to ~5 km, it is 0.01/km and then from ~5 to 15 km, and it is 0.002/km. Previously, frictional strength could be qualitatively determined by heat flow measurements. It is difficult to obtain the quantitative heat flow data for the SAF because the measured heat flow data exhibit large scatter. However, our quantitative results of frictional strength can be employed to investigate the heat flow in the southern SAF. We use a physical quantity P f to describe heat flow. It represents the dissipative friction heat power per unit area generated by the relative motion of two tectonic plates accommodated by off-fault deformation. P f is called "fault friction heat." On the basis of our determined frictional strength data, utilizing the method of 3D dynamic faulting analysis, we quantitatively determine the regional long-term fault

  2. Flow and Chemistry Pulsations, Monterey: Implications for Stress Transient Modulations of Hydrologic and Geochemical Systems in the Greater San Andreas Fault Zone

    Science.gov (United States)

    Brown, K. M.; Fueri, E.; Hilton, D. R.

    2005-12-01

    Submarine fluid venting at continental shelf and slope regions has been recognized over the past ten years as an important, yet under-studied process in marine science. Seeps are now known to be a general feature of the hydrogeology of many tectonically active continental margins. The eastern Pacific margin is characterized by a variety of tectonic settings (i.e. convergent and strike-slip) where active venting of fluids and gases has been documented. Reports include vents off Alaska, Costa Rica, Monterey Bay, Eel River basin, and Heceta Bay, OR. Indications of seismic tremor, linked to hydrologic transience in the offshore regions of subduction zones have recently been published elsewhere (see Brown et al, EPSL 2005). We now address here the varying nature of submarine fluid discharges in a San Andreas strike-slip setting. A key element of the proposed work is the combined multidisciplinary measurement of fluid flow, seep temperatures, and dissolved noble gases and chemistry of the Monterey seep sites at Extrovert Cliff. The seeps are situated close to several active strike-slip faults including the Monterey and San Gregorio fault zones. Initial results of 2 week deployments in 2004 of flow meters at Extravert Cliff indicated high flow rates and elevated seep temperatures that vary by as much as a factor of 2 on diurnal time scales with subtle changes over longer periods (>2 weeks). There are also indicative chemical signals of deeply sourced fluids that vary widely with time that show the following signals: 1) Elevated abundances of both mantle derived Helium (3He) as well as 4He and 40Ar of radiogenic crustal relevant trace element components; 2) Altered fluid chemistry (including, Ca Mg, Li and B); 3) The fluid temperature, flow rates, and gas chemistry, in particular, vary with time. We have both long-term and sub-diurnal variations in flow and temperature as well as the 3He/4He ratios, helium concentration, CO2 concentration and d13C values perhaps influenced

  3. Preliminary Holocene History of Fault Slip for the Mojave Section of the San Andreas Fault

    Science.gov (United States)

    Compton, T.; Cowgill, E.; Scharer, K. M.; Gold, R. D.; Westerteiger, R.; Bernardin, T. S.; Kellogg, L. H.

    2012-12-01

    The Mojave section of the San Andreas fault (MSAF) shows an apparent discrepancy between slip rates where geodetic rates are systematically slower relative to geologic rates. Resolving this discrepancy is important for determining whether or not the MSAF exhibits temporal changes in slip, advancing the understanding of the mechanical behavior of fault systems, and improving seismic-hazard assessment for the MSAF. Paleoseismic data along the MSAF suggest temporal variations in strain release over the last 2 kyr, but more studies are needed to extend the slip history back in time. Here we address the problem of the apparent slip rate discrepancy and possible temporal variations in strain release by employing Monte Carlo analysis of previously reported displacement-time data to investigate the extent to which these data constrain the Holocene slip history. We evaluated 42 previously reported piercing lines for possible inclusion in our analysis, 15 of which were unused because they are either duplicate reports or poorly documented. The remaining 27 data points reveal that slip rates are nonexistent for 5 offset distances (19-27m, 33-42m, 45-63m, 65-129m, and 131-300m) and for 3 time periods from 10-3.9 kyr, 3.9-2.8 kyr, and 2.8-1.4 kyr BP. Results of this analysis suggest slip rate along the MSAF varied between 0 and 4.5 kyr BP, with 5 possible phases of strain release, 3 of which are faster than the average of ~30 mm/yr. The oldest fast phase was from 4.5-2.9 kyr with an average slip rate of 61 mm/yr. The next fast phase, with an average rate of 81 mm/yr, was from 1.5-1.1 kyr. The youngest fast phase resulted in a rate of 36 mm/yr between 0.4 kyr and the 1857 event. Slower phases of slip occurred from 2.9-1.5 kyr, with an average rate of 12 mm/yr, and from 1.1-0.4 kyr, with a slip rate of 20 mm/yr. These slip history findings are considered preliminary because they are based on a limited dataset that contain data gaps. To aide in our search for additional potentially

  4. Seismic tomography and deformation modeling of the junction of the San Andreas and Calaveras faults

    Science.gov (United States)

    Dorbath, C.; Oppenheimer, D.; Amelung, F.; King, G.

    1996-01-01

    Local earthquake P traveltime data is inverted to obtain a three-dimensional tomographic image of the region centered on the junction of the San Andreas and Calaveras faults. The resulting velocity model is then used to relocate more than 17,000 earthquakes and to produce a model of fault structure in the region. These faults serve as the basis for modeling the topography using elastic dislocation methods. The region is of interest because active faults join, it marks the transition zone from creeping to locked fault behavior on the San Andreas fault, it exhibits young topography, and it has a good spatial distribution of seismicity. The tomographic data set is extensive, consisting of 1445 events, 96 stations, and nearly 95,000 travel time readings. Tomographic images are resolvable to depths of 12 km and show significant velocity contrasts across the San Andreas and Calaveras faults, a low-velocity zone associated with the creeping section of the San Andreas fault, and shallow low-velocity sediments in the southern Santa Clara valley and northern Salinas valley. Relocated earthquakes only occur where vp>5 km/s and indicate that portions of the San Andreas and Calaveras faults are non vertical, although we cannot completely exclude the possibility that all or part of this results from ray tracing problems. The new dips are more consistent with geological observations that dipping faults intersect the surface where surface traces have been mapped. The topographic modeling predicts extensive subsidence in regions characterized by shallow low-velocity material, presumably the result of recent sedimentation. Some details of the topography at the junction of the San Andreas and Calaveras faults are not consistent with the modeling results, suggesting that the current position of this "triple junction" has changed with time. The model also predicts those parts of the fault subject to contraction or extension perpendicular to the fault strike and hence the sense of any

  5. Correction to “Constraints on the stress state of the San Andreas Fault with analysis based on core and cuttings from San Andreas Fault Observatory at Depth (SAFOD) drilling phases 1 and 2”

    Science.gov (United States)

    Tembe, Sheryl; Lockner, David; Wong, Teng-Fong

    2010-01-01

    This article corrects: Constraints on the stress state of the San Andreas Fault with analysis based on core and cuttings from San Andreas Fault Observatory at Depth (SAFOD) drilling phases 1 and 2. Vol. 114, Issue B11, Article first published online: 5 NOV 2009.

  6. A case for historic joint rupture of the San Andreas and San Jacinto faults

    Science.gov (United States)

    Lozos, Julian C.

    2016-01-01

    The San Andreas fault is considered to be the primary plate boundary fault in southern California and the most likely fault to produce a major earthquake. I use dynamic rupture modeling to show that the San Jacinto fault is capable of rupturing along with the San Andreas in a single earthquake, and interpret these results along with existing paleoseismic data and historic damage reports to suggest that this has likely occurred in the historic past. In particular, I find that paleoseismic data and historic observations for the ~M7.5 earthquake of 8 December 1812 are best explained by a rupture that begins on the San Jacinto fault and propagates onto the San Andreas fault. This precedent carries the implications that similar joint ruptures are possible in the future and that the San Jacinto fault plays a more significant role in seismic hazard in southern California than previously considered. My work also shows how physics-based modeling can be used for interpreting paleoseismic data sets and understanding prehistoric fault behavior. PMID:27034977

  7. Variability of fault slip behavior along the San Andreas Fault in the San Juan Bautista Region

    Science.gov (United States)

    Taira, Taka'aki; Bürgmann, Roland; Nadeau, Robert M.; Dreger, Douglas S.

    2014-12-01

    An improved understanding of the time history of fault slip at depth is an essential step toward understanding the underlying mechanics of the faulting process. Using a waveform cross-correlation approach, we document spatially and temporally varying fault slip along the northernmost creeping section of the San Andreas Fault near San Juan Bautista (SJB), California, by systematically examining spatiotemporal behaviors of characteristically repeating earthquakes (CREs). The spatial distribution of pre-1998 SJB earthquake (1984-1998) fault slip rate inferred from the CREs reveals a ~15 km long low creep or partially locked section located near the 1998 Mw 5.1 SJB earthquake rupture. A finite-fault slip inversion reveals that the rupture of the 1998 SJB earthquake is characterized by the failure of a compact ~4 km2 asperity with a maximum slip of about 90 cm and corresponding peak stress drop of up to 50 MPa, whereas the mean stress drop is about 15 MPa. Following the 1998 earthquake, the CRE activity was significantly increased in a 5-10 km deep zone extending 2-7 km northwest of the main shock, which indicates triggering of substantial aseismic slip. The postseismic slip inferred from the CRE activity primarily propagated to the northwest and released a maximum slip of 9 cm. In this 5-10 km depth range, the estimated postseismic moment release is 8.6 × 1016 N m, which is equivalent to Mw 5.22. The aseismic slip distribution following the 1998 earthquake is not consistent with coseismic stress-driven afterslip but represents a triggered, long-lasting slow earthquake.

  8. Elevated time-dependent strengthening rates observed in San Andreas Fault drilling samples

    Science.gov (United States)

    Ikari, Matt J.; Carpenter, Brett M.; Vogt, Christoph; Kopf, Achim J.

    2016-09-01

    The central San Andreas Fault in California is known as a creeping fault, however recent studies have shown that it may be accumulating a slip deficit and thus its seismogenic potential should be seriously considered. We conducted laboratory friction experiments measuring time-dependent frictional strengthening (healing) on fault zone and wall rock samples recovered during drilling at the San Andreas Fault Observatory at Depth (SAFOD), located near the southern edge of the creeping section and in the direct vicinity of three repeating microearthquake clusters. We find that for hold times of up to 3000 s, frictional healing follows a log-linear dependence on hold time and that the healing rate is very low for a sample of the actively shearing fault core, consistent with previous results. However, considering longer hold times up to ∼350,000 s, the healing rate accelerates such that the data for all samples are better described by a power law relation. In general, samples having a higher content of phyllosilicate minerals exhibit low log-linear healing rates, and the notably clay-rich fault zone sample also exhibits strong power-law healing when longer hold times are included. Our data suggest that weak faults, such as the creeping section of the San Andreas Fault, can accumulate interseismic shear stress more rapidly than expected from previous friction data. Using the power-law dependence of frictional healing on hold time, calculations of recurrence interval and stress drop based on our data accurately match observations of discrete creep events and repeating Mw = 2 earthquakes on the San Andreas Fault.

  9. The wister mud pot lineament: Southeastward extension or abandoned strand of the San Andreas fault?

    Science.gov (United States)

    Lynch, D.K.; Hudnut, K.W.

    2008-01-01

    We present the results of a survey of mud pots in the Wister Unit of the Imperial Wildlife Area. Thirty-three mud pots, pot clusters, or related geothermal vents (hundreds of pots in all) were identified, and most were found to cluster along a northwest-trending line that is more or less coincident with the postulated Sand Hills fault. An extrapolation of the trace of the San Andreas fault southeastward from its accepted terminus north of Bombay Beach very nearly coincides with the mud pot lineament and may represent a surface manifestation of the San Andreas fault southeast of the Salton Sea. Additionally, a recent survey of vents near Mullet Island in the Salton Sea revealed eight areas along a northwest-striking line where gas was bubbling up through the water and in two cases hot mud and water were being violently ejected.

  10. Investigating Fault Slip and Rheology Along the San Andreas Fault in the San Juan Bautista Region

    Science.gov (United States)

    Taira, T.; Burgmann, R.; Nadeau, R. M.; Dreger, D. S.

    2012-12-01

    An improved understanding of the connection between seismic behavior and fault-zone rheology at depth is an essential step toward understanding the underlying mechanics of the faulting process. We investigate the seismicity along the northernmost creeping section of the San Andreas fault near San Juan Bautista (SJB), California, by systematically examining spatiotemporal behaviors of the aftershock sequences following the 12 August 1998 Mw 5.1 SJB earthquake. This 1998 SJB earthquake was the largest historic earthquake in the SJB area and was associated with a large slow slip event. Using a waveform cross-correlation approach (Peng and Zhao, 2009, NatureGeo), we have detected previously uncataloged earthquakes (about 500 events), resolving details of the aftershock activity in a zone at a depth of 9 km about 7 km northwest of the 1998 SJB mainshock. This aftershock zone is marked by one of the highest changes in the seismicity rate, exhibiting a delayed peak (about 20 hours after the mainshock) in the rate of aftershocks preceded by a period of very low rate of aftershocks since the mainshock. Subsequently, the rate of aftershocks shows power-law decay with time for about 1 month, and then the aftershock activity approached the pre-earthquake background level. This temporal behavior of the aftershock activity is different from the predicted aftershock decay based on the model of Dieterich (1994, JGR). Instead, our observation is more consistent with the decay rate of aftershocks occurring in the transition zone between locked and stable slip, as simulated numerically by Kaneko and Lapusta (2008, JGR). Our waveform analysis also identifies over 20 repeating microearthquake sequences (or groups of earthquakes with similar waveforms) associated with the 1998 SJB mainshock. The majority of the sequences have events occurring in the first month of the postseismic period. In other words, they reflect short-lived, accelerated repeater recurrences activated by the 1998 SJB

  11. Habitat information in the region on the underwater San Andreas Fault - Topic: Exploring the Undersea San Andreas Fault: Revealing the Past, Present, and Future at the Centennial of the Great 1906 Earthquake

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During this exploration, the first comprehensive high-resolution multi-beam sonar and seismic reflection survey of the Northern San Andreas Fault (NSAF) was...

  12. A permeability and compliance contrast measured hydrogeologically on the San Andreas Fault

    Science.gov (United States)

    Xue, Lian; Brodsky, Emily E.; Erskine, Jon; Fulton, Patrick M.; Carter, Reed

    2016-03-01

    Hydrogeologic properties of fault zones are critical to faulting processes; however, they are not well understood and difficult to measure in situ, particularly in low-permeability fractured bedrock formations. Analysis of continuous water level response to Earth tides in monitoring wells provides a method to measure the in situ hydrogeologic properties. We utilize four monitoring wells within the San Andreas Fault zone near Logan Quarry to study the fault zone hydrogeologic architecture by measuring the water level tidal response. The specific storage and permeability inferred from the tidal response suggest that there is a difference in properties at different distances from the fault. The sites closer to the fault have higher specific storage and higher permeability than farther from the fault. This difference of properties might be related to the fault zone fracture distribution decreasing away from the fault. Although permeability channels near faults have been documented before, the difference in specific storage near the fault is a new observation. The inferred compliance contrast is consistent with prior estimates of elastic moduli in the near-fault environment, but the direct measurements are new. The combination of measured permeability and storage yields a diffusivity of about 10-2 m2/s at all the sites both near and far from the fault as a result of the competing effects of permeability and specific storage. This uniform diffusivity structure suggests that the permeability contrast might not efficiently trap fluids during the interseismic period.

  13. Low-altitude aerial color digital photographic survey of the San Andreas Fault

    Science.gov (United States)

    Lynch, David K.; Hudnut, Kenneth W.; Dearborn, David S.P.

    2010-01-01

    Ever since 1858, when Gaspard-Félix Tournachon (pen name Félix Nadar) took the first aerial photograph (Professional Aerial Photographers Association 2009), the scientific value and popular appeal of such pictures have been widely recognized. Indeed, Nadar patented the idea of using aerial photographs in mapmaking and surveying. Since then, aerial imagery has flourished, eventually making the leap to space and to wavelengths outside the visible range. Yet until recently, the availability of such surveys has been limited to technical organizations with significant resources. Geolocation required extensive time and equipment, and distribution was costly and slow. While these situations still plague older surveys, modern digital photography and lidar systems acquire well-calibrated and easily shared imagery, although expensive, platform-specific software is sometimes still needed to manage and analyze the data. With current consumer-level electronics (cameras and computers) and broadband internet access, acquisition and distribution of large imaging data sets are now possible for virtually anyone. In this paper we demonstrate a simple, low-cost means of obtaining useful aerial imagery by reporting two new, high-resolution, low-cost, color digital photographic surveys of selected portions of the San Andreas fault in California. All pictures are in standard jpeg format. The first set of imagery covers a 92-km-long section of the fault in Kern and San Luis Obispo counties and includes the entire Carrizo Plain. The second covers the region from Lake of the Woods to Cajon Pass in Kern, Los Angeles, and San Bernardino counties (151 km) and includes Lone Pine Canyon soon after the ground was largely denuded by the Sheep Fire of October 2009. The first survey produced a total of 1,454 oblique digital photographs (4,288 x 2,848 pixels, average 6 Mb each) and the second produced 3,762 nadir images from an elevation of approximately 150 m above ground level (AGL) on the

  14. Elemental Geochemistry of Samples From Fault Segments of the San Andreas Fault Observatory at Depth (SAFOD) Drill Hole

    Science.gov (United States)

    Tourscher, S. N.; Schleicher, A. M.; van der Pluijm, B. A.; Warr, L. N.

    2006-12-01

    Elemental geochemistry of mudrock samples from phase 2 drilling of the San Andreas Fault Observatory at Depth (SAFOD) is presented from bore hole depths of 3066 m to 3169 m and from 3292 m to 3368 m, which contain a creeping section and main trace of the fault, respectively. In addition to preparation and analysis of whole rock sample, fault grains with neomineralized, polished surfaces were hand picked from well-washed whole rock samples, minimizing the potential contamination from drilling mud and steel shavings. The separated fractions were washed in deionized water, powdered using a mortar and pestle, and analyzed using an Inductively Coupled Plasma- Optical Emission Spectrometer for major and minor elements. Based on oxide data results, systematic differences in element concentrations are observed between the whole rock and fault rock. Two groupings of data points are distinguishable in the regions containing the main trace of the fault, a shallow part (3292- 3316 m) and a deeper section (3320-3368 m). Applying the isocon method, assuming Zr and Ti to be immobile elements in these samples, indicates a volume loss of more than 30 percent in the shallow part and about 23 percent in the deep part of the main trace. These changes are minimum estimates of fault-related volume loss, because the whole rock from drilling samples contains variable amount of fault rock as well. Minimum estimates for volume loss in the creeping section of the fault are more than 50 percent when using the isocon method, comparing whole rock to plucked fault rock. The majority of the volume loss in the fault rocks is due to the dissolution and loss of silica, potassium, aluminum, sodium and calcium, whereas (based on oxide data) the mineralized surfaces of fractures appear to be enriched in Fe and Mg. The large amount of element mobility within these fault traces suggests extensive circulation of hydrous fluids along fractures that was responsible for progressive dissolution and leaching

  15. Paleoseismic Studies of the Peninsula San Andreas Fault near Crystal Springs Reservoir, Woodside, California

    Science.gov (United States)

    Prentice, C. S.; Zachariasen, J. A.; Kozaci, O.; Clahan, K.; Sickler, R. R.; Rosa, C. M.; Hassett, W.; Feigelson, L.; Haproff, P. J.; DeLong, S.; Perkins, A.; Brooks, B. A.; Delano, J.; Baldwin, J. N.

    2013-12-01

    The Peninsula section of the San Andreas Fault (SAFP) is within 10 km of downtown San Francisco, making it among the most significant contributors to seismic hazard in the San Francisco Bay area. However, the history of earthquakes along this fault is poorly known. The most recent ground-rupturing earthquake occurred in 1906, but the ages of earlier earthquakes associated with surface rupture on this fault segment remain uncertain. Most researchers assume that the historically documented earthquake in 1838 occurred on the SAFP, but no definitive evidence of surface rupture at that time has been found. South of Crystal Springs Reservoir, the San Andreas Fault zone is expressed as a prominent fault scarp that is cut back in several locations by recent fluvial processes. At our Crystal Springs South (CSS) trench site, the fault is expressed as a low scarp with no other surface expression to suggest additional young fault traces. Excavations at this site revealed two distinct sets of faults, a younger set of faults that extend nearly to the modern ground surface that we assume represent the 1906 surface rupture, and an older set of faults that terminate lower in the stratigraphic section and are overlain by a scarp-derived colluvial deposit. Radiocarbon dating constrains the age of this older earthquake to 830-930 Cal. years BP. We determined that a buried channel deposit that dates to 790-960 Cal. years BP is displaced approximately 6-7m across both sets of faults. The closest 1906 offset measurement was made about 11 km northwest of this site, and is about 2.9m. Therefore our measurement of 6-7m of offset on the buried channel deposit at the CSS site could represent slip from 1906 and only one previous event comparable in size to the 1906 earthquake. The surprisingly old age of the earlier earthquake raises concerns that one or both of the event horizons exposed at the CSS site could represent multiple earthquakes. We therefore excavated an exploratory trench about 0

  16. Holocene geologic slip rate for the Banning strand of the southern San Andreas Fault, southern California

    Science.gov (United States)

    Gold, Peter O.; Behr, Whitney M.; Rood, Dylan; Sharp, Warren D.; Rockwell, Thomas; Kendrick, Katherine J.; Salin, Aaron

    2015-01-01

    Northwest directed slip from the southern San Andreas Fault is transferred to the Mission Creek, Banning, and Garnet Hill fault strands in the northwestern Coachella Valley. How slip is partitioned between these three faults is critical to southern California seismic hazard estimates but is poorly understood. In this paper, we report the first slip rate measured for the Banning fault strand. We constrain the depositional age of an alluvial fan offset 25 ± 5 m from its source by the Banning strand to between 5.1 ± 0.4 ka (95% confidence interval (CI)) and 6.4 + 3.7/−2.1 ka (95% CI) using U-series dating of pedogenic carbonate clast coatings and 10Be cosmogenic nuclide exposure dating of surface clasts. We calculate a Holocene geologic slip rate for the Banning strand of 3.9 + 2.3/−1.6 mm/yr (median, 95% CI) to 4.9 + 1.0/−0.9 mm/yr (median, 95% CI). This rate represents only 25–35% of the total slip accommodated by this section of the southern San Andreas Fault, suggesting a model in which slip is less concentrated on the Banning strand than previously thought. In rejecting the possibility that the Banning strand is the dominant structure, our results highlight an even greater need for slip rate and paleoseismic measurements along faults in the northwestern Coachella Valley in order to test the validity of current earthquake hazard models. In addition, our comparison of ages measured with U-series and 10Be exposure dating demonstrates the importance of using multiple geochronometers when estimating the depositional age of alluvial landforms.

  17. The San Andreas Fault revisited through seismic-noise and surface-wave tomography

    OpenAIRE

    P. Roux; Wathelet, Marc; Roueff, A.

    2011-01-01

    We present here surface-wave tomography results for the San Andreas Fault in the Parkfield area, California, USA, that were extracted from microseismic noise in the 0.15 Hz to 0.35 Hz frequency band using passive seismic-correlation techniques. Using directive noise incoming from the Pacific Ocean, passive seismic-noise tomography was performed using three-component sensors from a dense seismic network. A rotation algorithm was applied to the nine-component noise-correlation tensor that optim...

  18. Constraints on the stress state of the San Andreas Fault with analysis based on core and cuttings from San Andreas Fault Observatory at Depth (SAFOD) drilling phases 1 and 2

    Science.gov (United States)

    Tembe, S.; Lockner, D.; Wong, T.-F.

    2009-01-01

    Analysis of field data has led different investigators to conclude that the San Andreas Fault (SAF) has either anomalously low frictional sliding strength (?? 0.6). Arguments for the apparent weakness of the SAF generally hinge on conceptual models involving intrinsically weak gouge or elevated pore pressure within the fault zone. Some models assert that weak gouge and/or high pore pressure exist under static conditions while others consider strength loss or fluid pressure increase due to rapid coseismic fault slip. The present paper is composed of three parts. First, we develop generalized equations, based on and consistent with the Rice (1992) fault zone model to relate stress orientation and magnitude to depth-dependent coefficient of friction and pore pressure. Second, we present temperature-and pressure-dependent friction measurements from wet illite-rich fault gouge extracted from San Andreas Fault Observatory at Depth (SAFOD) phase 1 core samples and from weak minerals associated with the San Andreas Fault. Third, we reevaluate the state of stress on the San Andreas Fault in light of new constraints imposed by SAFOD borehole data. Pure talc (?????0.1) had the lowest strength considered and was sufficiently weak to satisfy weak fault heat flow and stress orientation constraints with hydrostatic pore pressure. Other fault gouges showed a systematic increase in strength with increasing temperature and pressure. In this case, heat flow and stress orientation constraints would require elevated pore pressure and, in some cases, fault zone pore pressure in excess of vertical stress. Copyright 2009 by the American Geophysical Union.

  19. Holocene Geologic Slip Rate for the Banning Strand of the Southern San Andreas Fault near San Gorgonio Pass, Southern California

    Science.gov (United States)

    Gold, P. O.; Behr, W. M.; Rood, D. H.; Kendrick, K. J.; Rockwell, T. K.; Sharp, W. D.

    2014-12-01

    We present the first Holocene geologic slip rate for the Banning strand of the southern San Andreas Fault in southern California. The southern San Andreas Fault splays into the sub-parallel Banning and Mission Creek strands in the northwestern Coachella Valley, and although it has long been surmised that the Banning strand eventually accommodates the majority of displacement and transfers it into San Gorgonio Pass, until now it has been uncertain how slip is actually partitioned between these two fault strands. Our new slip rate measurement, critically located at the northwestern end of the Banning strand, overlaps within errors with the published rate for the southern San Andreas Fault measured at Biskra Palms Oasis. This indicates that the majority of southern San Andreas Fault displacement transfers from the southeastern Mission Creek strand northwest to the Banning strand and into San Gorgonio Pass. Our result corroborates the UCERF3 hazard model, and is consistent with most previous interpretations of how slip is partitioned between the Banning and Mission Creek fault strands. To measure this slip rate, we used B4 airborne LiDAR to identify the apex of an alluvial fan offset laterally 30 ± 5 m from its source. We calculated the depositional age of the fan using 10Be in-situ cosmogenic exposure dating of 5 cobbles and a depth profile. We calculated a most probable fan age of 4.0 +2.0/-1.6 ka (1σ) by combining the inheritance-corrected cobble ages assuming Gaussian uncertainty. However, the probability density function yielded a multi-peaked distribution, which we attribute to variable 10Be inheritance in the cobbles, so we favor the depth profile age of 2.2-3.6 ka. Combined, these measurements yield a late Holocene slip rate for the Banning strand of the southern San Andreas Fault of 11.1 +3.1/-3.3 mm/yr. This slip rate does not preclude possibility that some slip transfers north along the Mission Creek strand and the Garnet Hill fault, but it does confirm

  20. Bimodal distribution of creep event amplitudes on the San Andreas fault, California

    Science.gov (United States)

    Burford, R.O.

    1977-01-01

    EPISODIC fault creep, at several instrument sites along the San Andreas and associated faults in central California consists of a few small and large slip events per year generally superimposed on a background of gradual yielding at low rates1-3. Most of the events are aseismic, but a few minor displacement steps have occured in association with local earthquakes 12. After removal of earthquake steps, event lists for several sites include significant numbers of small events about an order or magnitude below the typical 1-4-mm amplitude range for large events1, 3. Recent experimental rock-deformation results demonstrate that under biaxial loading some rocks show episodic slip on pre-cut surfaces9,10. It is not yet clear how the laboratory and field observations are related, but the data presented here indicate that episodic fault creep in nature may be more complex than previously realised. In light of the laboratory results, it is more important than ever to consider all the details of the field data concerning fault creep. ?? 1977 Nature Publishing Group.

  1. Mineral carbonation of serpentinite in the San Andreas Fault: Implications for aseismic creep

    Science.gov (United States)

    Klein, F.; Goldsby, D. L.; Lin, J.

    2013-12-01

    Here we present a new model that highlights the impact of peridotite-water-CO2 interactions on aseismic creep in the San Andreas Fault (SAF) zone. Serpentinization of peridotite is commonly invoked as the cause of aseismic slip (creep) observed in the SAF of central and northern California, as the creeping section coincides with the mapped extent of the Coast Range ophiolite (Irwin and Barnes, 1975). However, more recently it has been demonstrated that serpentinization alone cannot account for the high rates of aseismic slip (Moore et al., 1996). Moore and Rymer (2007) hypothesized that the reaction of silica-rich fluids with serpentinite causes the formation of mechanically weak talc, which is presently held responsible for fault-zone weakening in this area. While silica-metasomatism can transform serpentinite into steatite (talc rock), the common and widespread occurrence of CO2-rich springs in the fault zone, and silica-carbonate altered serpentinite, points to carbonation (i.e., CO2-metasomatism) of serpentinite as the major cause of fault-zone weakening in central and northern California. Initial results of our field program, mineralogical analyses and friction experiments will be presented, which highlight the evolution in shear strength from serpentine, to soapstone (talc-magnesite rock), to listvenite (quartz-magnesite rock), the final product of CO2-metasomatism.

  2. Detecting Significant Stress Drop Variations in Large Micro-Earthquake Datasets: A Comparison Between a Convergent Step-Over in the San Andreas Fault and the Ventura Thrust Fault System, Southern California

    Science.gov (United States)

    Goebel, T. H. W.; Hauksson, E.; Plesch, A.; Shaw, J. H.

    2016-06-01

    A key parameter in engineering seismology and earthquake physics is seismic stress drop, which describes the relative amount of high-frequency energy radiation at the source. To identify regions with potentially significant stress drop variations, we perform a comparative analysis of source parameters in the greater San Gorgonio Pass (SGP) and Ventura basin (VB) in southern California. The identification of physical stress drop variations is complicated by large data scatter as a result of attenuation, limited recording bandwidth and imprecise modeling assumptions. In light of the inherently high uncertainties in single stress drop measurements, we follow the strategy of stacking large numbers of source spectra thereby enhancing the resolution of our method. We analyze more than 6000 high-quality waveforms between 2000 and 2014, and compute seismic moments, corner frequencies and stress drops. Significant variations in stress drop estimates exist within the SGP area. Moreover, the SGP also exhibits systematically higher stress drops than VB and shows more scatter. We demonstrate that the higher scatter in SGP is not a generic artifact of our method but an expression of differences in underlying source processes. Our results suggest that higher differential stresses, which can be deduced from larger focal depth and more thrust faulting, may only be of secondary importance for stress drop variations. Instead, the general degree of stress field heterogeneity and strain localization may influence stress drops more strongly, so that more localized faulting and homogeneous stress fields favor lower stress drops. In addition, higher loading rates, for example, across the VB potentially result in stress drop reduction whereas slow loading rates on local fault segments within the SGP region result in anomalously high stress drop estimates. Our results show that crustal and fault properties systematically influence earthquake stress drops of small and large events and should

  3. Examining the Evolution of the Peninsula Segment of the San Andreas Fault, Northern California, Using a 4-D Geologic Model

    Science.gov (United States)

    Horsman, E.; Graymer, R. W.; McLaughlin, R. J.; Jachens, R. C.; Scheirer, D. S.

    2008-12-01

    Retrodeformation of a three-dimensional geologic model allows us to explore the tectonic evolution of the Peninsula segment of the San Andreas Fault and adjacent rock bodies in the San Francisco Bay area. By using geological constraints to quantitatively retrodeform specific surfaces (e.g. unfolding paleohorizontal horizons, removing fault slip), we evaluate the geometric evolution of rock bodies and faults in the study volume and effectively create a four-dimensional model of the geology. The three-dimensional map is divided into fault-bounded blocks and subdivided into lithologic units. Surface geologic mapping provides the foundation for the model. Structural analysis and well data allow extrapolation to a few kilometers depth. Geometries of active faults are inferred from double-difference relocated earthquake hypocenters. Gravity and magnetic data provide constraints on the geometries of low density Cenozoic deposits on denser basement, highly magnetic marker units, and adjacent faults. Existing seismic refraction profiles constrain the geometries of rock bodies with different seismic velocities. Together these datasets and others allow us to construct a model of first-order geologic features in the upper ~15 km of the crust. Major features in the model include the active San Andreas Fault surface; the Pilarcitos Fault, an abandoned strand of the San Andreas; an active NE-vergent fold and thrust belt located E of the San Andreas Fault; regional relief on the basement surface; and several Cenozoic syntectonic basins. Retrodeformation of these features requires constraints from all available datasets (structure, geochronology, paleontology, etc.). Construction of the three-dimensional model and retrodeformation scenarios are non-unique, but significant insights follow from restricting the range of possible geologic histories. For example, we use the model to investigate how the crust responded to migration of the principal slip surface from the Pilarcitos Fault

  4. Inferring fault rheology from low-frequency earthquakes on the San Andreas

    Science.gov (United States)

    Beeler, N. M.; Thomas, Amanda; Bürgmann, Roland; Shelly, David

    2013-11-01

    of recurring low-frequency earthquakes (LFEs) within nonvolcanic tremor (NVT) on the San Andreas fault in central California show strong sensitivity to shear stress induced by the daily tidal cycle. LFEs occur at all levels of the tidal shear stress and are in phase with the very small, ~400 Pa, stress amplitude. To quantitatively explain the correlation, we use a model from the existing literature that assumes the LFE sources are small, persistent regions that repeatedly fail during shear of a much larger scale, otherwise aseismically creeping fault zone. The LFE source patches see tectonic loading, creep of the surrounding fault which may be modulated by the tidal stress, and direct tidal loading. If the patches are small relative to the surrounding creeping fault then the stressing is dominated by fault creep, and if patch failure occurs at a threshold stress, then the resulting seismicity rate is proportional to the fault creep rate or fault zone strain rate. Using the seismicity rate as a proxy for strain rate and the tidal shear stress, we fit the data with possible fault rheologies that produce creep in laboratory experiments at temperatures of 400 to 600°C appropriate for the LFE source depth. The rheological properties of rock-forming minerals for dislocation creep and dislocation glide are not consistent with the observed fault creep because strong correlation between small stress perturbations and strain rate requires perturbation on the order of the ambient stress. The observed tidal modulation restricts ambient stress to be at most a few kilopascal, much lower than rock strength. A purely rate dependent friction is consistent with the observations only if the product of the friction rate dependence and effective normal stress is ~ 0.5 kPa. Extrapolating the friction rate strengthening dependence of phyllosilicates (talc) to depth would require the effective normal stress to be ~50 kPa, implying pore pressure is lithostatic. If the LFE source is on the

  5. Cradle of the Earthquake: Exploring the Underwater San Andreas Fault on the R/V Pacific Storm and the SRV Derek M. Baylis between 20100910 and 20101003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Over one hundred years after the devastating Great 1906 Earthquake that nearly destroyed San Francisco, this expedition explored the Northern San Andreas Fault, the...

  6. Correlation of clayey gouge in a surface exposure of the San Andreas fault with gouge at depth from SAFOD: Implications for the role of serpentinite in fault mechanics

    Science.gov (United States)

    Moore, Diane E.; Rymer, Michael J.

    2012-01-01

    Magnesium-rich clayey gouge similar to that comprising the two actively creeping strands of the San Andreas Fault in drill core from the San Andreas Fault Observatory at Depth (SAFOD) has been identified in a nearby outcrop of serpentinite within the fault zone at Nelson Creek. Each occurrence of the gouge consists of porphyroclasts of serpentinite and sedimentary rocks dispersed in a fine-grained, foliated matrix of Mg-rich smectitic clays. The clay minerals in all three gouges are interpreted to be the product of fluid-assisted, shear-enhanced reactions between quartzofeldspathic wall rocks and serpentinite that was tectonically entrained in the fault from a source in the Coast Range Ophiolite. We infer that the gouge at Nelson Creek connects to one or both of the gouge zones in the SAFOD core, and that similar gouge may occur at depths in between. The special significance of the outcrop is that it preserves the early stages of mineral reactions that are greatly advanced at depth, and it confirms the involvement of serpentinite and the Mg-rich phyllosilicate minerals that replace it in promoting creep along the central San Andreas Fault.

  7. Near-surface structure of the 1906 main trace of the San Andreas Fault, San Francisco peninsula segment, California

    Science.gov (United States)

    Rosa, C.; Catchings, R. D.; Rymer, M. J.; Goldman, M.; Grove, K.; Prentice, C. S.

    2012-12-01

    The peninsula segment of the San Andreas Fault (SAF) is forecasted to have the second highest probability of producing a M6.7 or greater earthquake in the San Francisco Bay Area in the next 30 years; yet, relatively little is known about its slip history. In most places, the surface location of the SAF has been determined primarily on the basis of geomorphic features and from mapping surface ruptures associated with the 1906 M7.9 San Francisco earthquake. To more precisely locate traces of this segment of the SAF along the San Francisco peninsula in the subsurface, we acquired a high-resolution seismic imaging survey, using both seismic refraction and reflection profiling, south of Upper Crystal Springs Reservoir near Woodside, California in June 2012. High-resolution seismic images produced from this study may benefit ongoing paleoseismological investigations along the SAF because the seismic data can be used to precisely locate the main fault trace and auxiliary faults that may contribute to the earthquake hazards associated with the fault zone. Furthermore, the seismic images provide insights into near-surface fault structure and P- and S-wave velocities, which can be important in understanding strong shaking resulting from future earthquakes along this segment of the SAF. We acquired both P- and S-wave data using a 60-channel seismograph system connected via cable to 40-Hz vertical-component and 4-Hz horizontal geophones, which were spaced at 1-m intervals along a 60-m-long transect. Seismic sources (shots) were generated by hammer impacts on a steel plate or aluminum block at each geophone location. All shots were recorded on all channels. This survey design permits simultaneous acquisition of reflection and refraction data so that both refraction tomography and reflection images can be developed. Our initial analysis of the P-wave data shows that seismic velocities across the main trace of the SAF vary from about 700 m/s near the surface to more than 2500 m

  8. Subsurface geometry of the San Andreas-Calaveras fault junction: influence of serpentinite and the Coast Range Ophiolite

    Science.gov (United States)

    Watt, Janet Tilden; Ponce, David A.; Graymer, Russell W.; Jachens, Robert C.; Simpson, Robert W.

    2014-01-01

    While an enormous amount of research has been focused on trying to understand the geologic history and neotectonics of the San Andreas-Calaveras fault (SAF-CF) junction, fundamental questions concerning fault geometry and mechanisms for slip transfer through the junction remain. We use potential-field, geologic, geodetic, and seismicity data to investigate the 3-D geologic framework of the SAF-CF junction and identify potential slip-transferring structures within the junction. Geophysical evidence suggests that the San Andreas and Calaveras fault zones dip away from each other within the northern portion of the junction, bounding a triangular-shaped wedge of crust in cross section. This wedge changes shape to the south as fault geometries change and fault activity shifts between fault strands, particularly along the Calaveras fault zone (CFZ). Potential-field modeling and relocated seismicity suggest that the Paicines and San Benito strands of the CFZ dip 65° to 70° NE and form the southwest boundary of a folded 1 to 3 km thick tabular body of Coast Range Ophiolite (CRO) within the Vallecitos syncline. We identify and characterize two steeply dipping, seismically active cross structures within the junction that are associated with serpentinite in the subsurface. The architecture of the SAF-CF junction presented in this study may help explain fault-normal motions currently observed in geodetic data and help constrain the seismic hazard. The abundance of serpentinite and related CRO in the subsurface is a significant discovery that not only helps constrain the geometry of structures but may also help explain fault behavior and the tectonic evolution of the SAF-CF junction.

  9. Near-Surface Structure of the Peninsula Segment of the San Andreas Fault, San Francisco Bay Area, California

    Science.gov (United States)

    Rosa, C.; Catchings, R.; Rymer, M. J.; Goldman, M.; Grove, K.; Prentice, C. S.

    2013-12-01

    The peninsula segment of the San Andreas Fault (SAF) is a section of the fault that has the potential to produce the next large earthquake in the San Francisco Bay Area, yet the slip history of the peninsula segment is relatively unknown. In most places, the surface location of the SAF has been determined primarily on the basis of geomorphic features and from mapping surface ruptures associated with the 1906 M7.9 San Francisco earthquake. To more precisely locate traces of the SAF along the San Francisco peninsula in the subsurface, we acquired a high-resolution seismic imaging survey, using both seismic refraction and reflection profiling, south of Upper Crystal Springs Reservoir near Woodside, California in June 2012. We acquired coincident P- and S-wave data using a 60-channel seismograph system connected via cable to 40-Hz vertical-component and 4-Hz horizontal-component geophones, with spacing at 1-m intervals along a 60-m-long transect across the SAF. Seismic sources (shots) were generated by hammer impacts on a steel plate or aluminum block at each geophone location. All shots were recorded on all channels. This survey design permitted simultaneous acquisition of reflection and refraction data such that both refraction tomography and reflection images were developed. Analysis of the P- and S-wave data, using refraction tomography, shows abrupt variations in the P-wave (Vp) and S-wave (Vs) velocities, including the 1,500 m/s velocity contour that outlines the top to groundwater and images of Vp/Vs and Poisson's ratios. P-wave velocities range from about 700 m/s at the surface to more than 4000 m/s at 20-m depth. S-wave velocities range from about 300 m/s at the surface to about 800 m/s at 20-m depth. The combined data indicate that the near-surface trace of the SAF dips steeply to the southwest in the upper few tens of meters. Variations in the velocity images also suggest the possibility of two additional near-surface fault traces within about 25 m of the

  10. Tomographic imaging of the tectonic tremor zone beneath the San Andreas fault in the Parkfield region

    Science.gov (United States)

    Peterson, D. E.; Thurber, C. H.; Shelly, D. R.; Bennington, N. L.; Zhang, H.; Brown, J. R.

    2012-12-01

    The fine-scale seismic velocity structure around zones of tectonic (nonvolcanic) tremor and low-frequency earthquakes (LFE's) has been imaged successfully in subduction zones. This success is due in part to the occurrence of earthquakes in the subducting slab beneath the zone of tremor and LFE's. Such studies have found the tremor and LFE's to lie within zones of reduced seismic velocity and high Vp/Vs, which have been interpreted to reflect high pore fluid pressure (e.g., Shelly et al., 2006). For the San Andreas fault, the observed tremor and LFE's in the Parkfield region occur at depths greater than 15 km, which is below the deepest conventional earthquakes in the region. This makes tomographic imaging of the tremor zone more challenging. We use a combination of P and S arrival times and corresponding differential times from stacked seismograms of LFE's (Shelly and Hardebeck, 2010) along with absolute and differential times from shallower microearthquakes to image the three-dimensional P- and S- wave velocity structure to ~20 km depth. Our initial results indicate the LFE's near SAFOD lie within or adjacent to zones with slightly reduced P-wave velocity and more sharply reduced S- wave velocity. The estimated Vp/Vs values are approximately 1.85 to 1.95 in these zones. The elevated Vp/Vs values are interpreted to reflect high pore fluid pressure and low effective stress. This is consistent with results from subduction zones and with observations of triggering and tidal modulation of LFE's and tremor on this deep extension of the SAF. We will present refined tomography results that expand the area imaged and include additional LFE arrival time picks from temporary array data. Cross-section from SW to NE through SAFOD at Y=0. Vs is shown by black contours (labeled with km/sec) and colors from red (slow) to blue (fast). Black diamonds are hypocenters of LFE's and earthquakes used in the inversion.

  11. Late Holocene slip rate of the San Andreas fault and its accommodation by creep and moderate-magnitude earthquakes at Parkfield, California

    Science.gov (United States)

    Toke, N.A.; Arrowsmith, J.R.; Rymer, M.J.; Landgraf, A.; Haddad, D.E.; Busch, M.; Coyan, J.; Hannah, A.

    2011-01-01

    Investigation of a right-laterally offset channel at the Miller's Field paleoseismic site yields a late Holocene slip rate of 26.2 +6.4/-4.3 mm/yr (1??) for the main trace of the San Andreas fault at Park-field, California. This is the first well-documented geologic slip rate between the Carrizo and creeping sections of the San Andreas fault. This rate is lower than Holocene measurements along the Carrizo Plain and rates implied by far-field geodetic measurements (~35 mm/yr). However, the rate is consistent with historical slip rates, measured to the northwest, along the creeping section of the San Andreas fault (creep and observations of surface slip from the 28 September 2004 M6 Parkfield earthquake. Together, this slip rate and deformation fabric suggest that the historically observed San Andreas fault slip behavior along the Parkfield section has persisted for at least a millennium, and that significant slip is accommodated by structures in a zone beyond the main San Andreas fault trace. ?? 2011 Geological Society of America.

  12. Fault Tolerant Control Systems

    DEFF Research Database (Denmark)

    Bøgh, S.A.

    from this study highlights requirements for a dedicated software environment for fault tolerant control systems design. The second detailed study addressed the detection of a fault event and determination of the failed component. A variety of algorithms were compared, based on two fault scenarios in...... faults, but also that the research field still misses a systematic approach to handle realistic problems such as low sampling rate and nonlinear characteristics of the system. The thesis contributed with methods to detect both faults and specifically with a novel algorithm for the actuator fault...... detection that is superior in terms of performance and complexity to the other algorithms in the comparative study....

  13. Heterogeneous slip and rupture models of the San Andreas fault zone based upon three-dimensional earthquake tomography

    Energy Technology Data Exchange (ETDEWEB)

    Foxall, W.

    1992-11-01

    Crystal fault zones exhibit spatially heterogeneous slip behavior at all scales, slip being partitioned between stable frictional sliding, or fault creep, and unstable earthquake rupture. An understanding the mechanisms underlying slip segmentation is fundamental to research into fault dynamics and the physics of earthquake generation. This thesis investigates the influence that large-scale along-strike heterogeneity in fault zone lithology has on slip segmentation. Large-scale transitions from the stable block sliding of the Central 4D Creeping Section of the San Andreas, fault to the locked 1906 and 1857 earthquake segments takes place along the Loma Prieta and Parkfield sections of the fault, respectively, the transitions being accomplished in part by the generation of earthquakes in the magnitude range 6 (Parkfield) to 7 (Loma Prieta). Information on sub-surface lithology interpreted from the Loma Prieta and Parkfield three-dimensional crustal velocity models computed by Michelini (1991) is integrated with information on slip behavior provided by the distributions of earthquakes located using, the three-dimensional models and by surface creep data to study the relationships between large-scale lithological heterogeneity and slip segmentation along these two sections of the fault zone.

  14. Fault tolerant computing systems

    International Nuclear Information System (INIS)

    Fault tolerance involves the provision of strategies for error detection damage assessment, fault treatment and error recovery. A survey is given of the different sorts of strategies used in highly reliable computing systems, together with an outline of recent research on the problems of providing fault tolerance in parallel and distributed computing systems. (orig.)

  15. Strength of the Creeping Segment of the San Andreas Fault Inferred from Intact SAFOD Core Material

    Science.gov (United States)

    Lockner, D. A.; Morrow, C. A.; Moore, D. E.; Hickman, S.

    2012-12-01

    A primary goal of the SAFOD fault zone drilling project was to determine the strength and frictional properties of the San Andreas Fault (SAF) at seismogenic depth. Laboratory testing of SAFOD core material has now provided measurements under near-in-situ conditions of the shear strength of the creeping portion of the SAF at a vertical depth of 2.7 km. Early measurements made on SAFOD spot core and drilling cuttings before core from within the SAF zone was available [Tembe et al. (2006), Morrow et al. (2007), Carpenter et al. (2011)] associated low strength material with currently inactive faults southwest of the SAF and actively deforming zones associated with the SAF that were identified from casing deformation data. In Phase 3 drilling in 2007, core was retrieved from two actively deforming shear zones within the approximately 200-m-wide SAF damage zone. The two zones contained clay-rich foliated gouge and have been designated as the Southwest Deforming Zone (SDZ - width ~1.6 m) and Central Deforming Zone (CDZ - width ~2.6 m). Casing deformation [Zoback et al. (2010)] suggests that deformation is localized within these weak foliated gouge zones. Deformation tests on crushed and sieved samples of the foliated gouge [Lockner et al. (2011) and Carpenter et al. (2012)] showed low strength (coefficient of friction μ in the range 0.1 to 0.2) due to the high concentration of saponite, an Mg-rich smectite clay. We now present results from deformation tests on intact CDZ foliated gouge that, combined with similar deformation tests by Carpenter et al. (2012), allow comparison with crushed/sieved samples. We find: (1) no significant difference in strength of intact and crushed/sieved foliated gouge samples. Apparently, the high concentration of the weak mineral phase (>60%) makes strength variations due to fabric irrelevant in this case. Therefore, crushed/sieved samples that are significantly easier to prepare and test can be used to infer strength and other rheological

  16. Continuation of a deep borehole stress measurement profile near the San Andreas Fault: 2. Hydraulic fracturing stress measurements at Black Butte, Mojave Desert, California

    Science.gov (United States)

    Stock, J. M.; Healy, J. H.

    1988-12-01

    Hydraulic fracturing stress measurements were obtained in the Black Butte drill hole, 18 km northeast of the San Andreas fault in the Mojave Desert, at depths from 251 to 635 m. In all tests the least and greatest horizontal principal stresses (Sh and SH, respectively) exceeded the vertical stress (Sν), indicating a thrust faulting stress regime. A single good-quality hydraulic fracture impression from 309 m depth indicates an SH direction of N41°E ± 10°. This SH direction should be interpreted with caution because it is based on only one observation. This orientation is fairly compatible with nearby surface stress measurements but is incompatible with most of the hydraulic fracturing stress orientations reported from comparable depths in the Mojave Desert and is not favorable for right-lateral slip on either the San Andreas fault or NW striking faults present farther to the east. The stress regime measured in the Black Butte hole is comparable to that measured at nearby shallow depths but differs from the strike-slip or transitional (strike-slip to thrust faulting) stress regime present at similar depths in two nearby holes: Crystallaire, 4 km northeast of fhe San Andreas fault, and Hi Vista, 32 km northeast of the San Andreas fault. The SH direction measured in these holes is approximately 60° counterclockwise of that observed in the Black Butte hole. The differences in stress magnitudes and orientation among these holes substantiate previous indications of local variations in stress in the upper kilometer of the crust in this area and cast doubt on the validity of linear elastic models in which the effects of the San Andreas fault dominate the stress field in the western Mojave Desert.

  17. Scientific drilling into the San Andreas fault and site characterization research: Planning and coordination efforts. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Zoback, M.D.

    1998-08-30

    The fundamental scientific issue addressed in this proposal, obtaining an improved understanding of the physical and chemical processes responsible for earthquakes along major fault zones, is clearly of global scientific interest. By sampling the San Andreas fault zone and making direct measurements of fault zone properties to 4.0 km at Parkfield they will be studying an active plate-boundary fault at a depth where aseismic creep and small earthquakes occur and where a number of the scientific questions associated with deeper fault zone drilling can begin to be addressed. Also, the technological challenges associated with drilling, coring, downhole measurements and borehole instrumentation that may eventually have to be faced in deeper drilling can first be addressed at moderate depth and temperature in the Parkfield hole. Throughout the planning process leading to the development of this proposal they have invited participation by scientists from around the world. As a result, the workshops and meetings they have held for this project have involved about 350 scientists and engineers from about a dozen countries.

  18. Long-term slip rate of the southern San Andreas Fault, from 10Be-26Al surface exposure dating of an offset alluvial fan

    Energy Technology Data Exchange (ETDEWEB)

    der Woerd, J v; Klinger, Y; Sieh, K; Tapponnier, P; Ryerson, F; M?riaux, A

    2006-01-13

    We determine the long-term slip rate of the southern San Andreas Fault in the southeastern Indio Hills using {sup 10}Be and {sup 26}Al isotopes to date an offset alluvial fan surface. Field mapping complemented with topographic data, air photos and satellite images allow to precisely determine piercing points across the fault zone that are used to measure an offset of 565 {+-} 80 m. A total of twenty-six quartz-rich cobbles from three different fan surfaces were collected and dated. The tight cluster of nuclide concentrations from 19 samples out of 20 from the offset fan surface implies a simple exposure history, negligible prior exposure and erosion, and yield an age of 35.5 {+-} 2.5 ka. The long-term slip rate of the San Andreas Fault south of Biskra Palms is thus 15.9 {+-} 3.4 mm/yr. This rate is about 10 mm/yr slower than geological (0-14 ka) and short-term geodetic estimates for this part of the San Andreas Fault implying changes in slip rate or in faulting behavior. This result puts new constraints on the slip rate of the San Jacinto and on the Eastern California Shear Zone for the last 35 ka. Our study shows that more sites along the major faults of southern California need to be targeted to better constrain the slip-rates over different time scales.

  19. Precise location of San Andreas Fault tremors near Cholame, California using seismometer clusters: Slip on the deep extension of the fault?

    Science.gov (United States)

    Shelly, D.R.; Ellsworth, W.L.; Ryberg, T.; Haberland, C.; Fuis, G.S.; Murphy, J.; Nadeau, R.M.; Burgmann, R.

    2009-01-01

    We examine a 24-hour period of active San Andreas Fault (SAF) tremor and show that this tremor is largely composed of repeated similar events. Utilizing this similarity, we locate the subset of the tremor with waveforms similar to an identified low frequency earthquake (LFE) "master template," located using P and S wave arrivals to be ???26 km deep. To compensate for low signal-to-noise, we estimate event-pair differential times at "clusters" of nearby stations rather than at single stations. We find that the locations form a near-linear structure in map view, striking parallel to the SAF and near the surface trace. Therefore, we suggest that at least a portion of the tremor occurs on the deep extension of the fault, likely reflecting shear slip, similar to subduction zone tremor. If so, the SAF may extend to the base of the crust, ???10 km below the deepest regular earthquakes on the fault. ?? 2009 by the American Geophysical Union.

  20. Three-Dimensional Investigation of a 5 m Deflected Swale along the San Andreas Fault in the Carrizo Plain

    KAUST Repository

    Akciz, S. O.

    2014-10-21

    Topographic maps produced from Light Detection and Ranging (LiDAR) data are useful for paleoseismic and neotectonic research because they provide submeter representation of faulting-related surface features. Offset measurements of geomorphic features, made in the field or on a remotely sensed imagery, commonly assume a straight or smooth (i.e., undeflected) pre-earthquake geometry. Here, we present results from investigation of an ∼20 cm deep and >5 m wide swale with a sharp bend along the San Andreas fault (SAF) at the Bidart fan site in the Carrizo Plain, California. From analysis of LiDAR topography images and field measurements, the swale was initially interpreted as a channel tectonically offset ∼4:7 m. Our observations from exposures in four backhoe excavations and 25 hand-dug trenchettes show that even though a sharp bend in the swale coincides with the trace of the A.D. 1857 fault rupture, the swale formed after the 1857 earthquake and was not tectonically offset. Subtle fractures observed within a surficial gravel unit overlying the 1857 rupture trace are similar to fractures previously documented at the Phelan fan and LY4 paleoseismic sites 3 and 35 km northwest of Bidart fan, respectively. Collectively, the fractures suggest that a post-1857 moderate-magnitude earthquake caused ground cracking in the Carrizo and Cholame stretches of the SAF. Our observations emphasize the importance of excavation at key locations to validate remote and ground-based measurements, and we advocate more geomorphic characterization for each site if excavation is not possible.

  1. Fault detection and isolation in systems with parametric faults

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik

    1999-01-01

    The problem of fault detection and isolation of parametric faults is considered in this paper. A fault detection problem based on parametric faults are associated with internal parameter variations in the dynamical system. A fault detection and isolation method for parametric faults is formulated...

  2. Locating non-volcanic tremor along the San Andreas Fault using a multiple array source imaging technique

    Science.gov (United States)

    Ryberg, T.; Haberland, C.H.; Fuis, G.S.; Ellsworth, W.L.; Shelly, D.R.

    2010-01-01

    Non-volcanic tremor (NVT) has been observed at several subduction zones and at the San Andreas Fault (SAF). Tremor locations are commonly derived by cross-correlating envelope-transformed seismic traces in combination with source-scanning techniques. Recently, they have also been located by using relative relocations with master events, that is low-frequency earthquakes that are part of the tremor; locations are derived by conventional traveltime-based methods. Here we present a method to locate the sources of NVT using an imaging approach for multiple array data. The performance of the method is checked with synthetic tests and the relocation of earthquakes. We also applied the method to tremor occurring near Cholame, California. A set of small-aperture arrays (i.e. an array consisting of arrays) installed around Cholame provided the data set for this study. We observed several tremor episodes and located tremor sources in the vicinity of SAF. During individual tremor episodes, we observed a systematic change of source location, indicating rapid migration of the tremor source along SAF. ?? 2010 The Authors Geophysical Journal International ?? 2010 RAS.

  3. Physical and chemical characterization of pulverized granite from a shallow drill along the San Andreas Fault, Little Rock, CA

    Science.gov (United States)

    Wechsler, N.; Allen, E. E.; Rockwell, T. K.; Chester, J. S.; Girty, G. H.; Ben-Zion, Y.

    2008-12-01

    We present results from a continuous 42 meter deep core through damaged granitoids adjacent to the San Andreas fault near Little Rock Creek. We employed several methods to measure particle size distribution (pipette, elutriator, laser particle analyzer), as well as x-ray diffraction and fluorescence (XRD, XRF) methods to investigate the relation between depth, pulverization and chemical processes that may affect the degree of damage. The drill site is characterized by extensive outcrops of granitic rocks with varying degrees of damage at distances of up to a few hundreds of meters from the fault's primary active strand. The drill core is composed mainly of pulverized granite and granodiorite, and crosses several high clay content secondary shears. Results of particle size distributions measured using standard sieving and pipette methods indicate that medium to coarse silt and fine sand are the dominant particle size range in the cored section, similar to pulverized granitic rocks analyzed by Rockwell et al. (2008). Very few clay-size particles were observed, but minor amounts of clay weathering products are present. We observe a minor shift in the particle size distribution towards finer sizes with depth, in agreement with the results of Anderson et al. (1980), and find somewhat different distributions for different lithologies. Several zones displaying significant chemical alteration were captured over the cored interval, but XRF data indicate that there is no systematic change in chemical alteration with depth. Where substantial chemical alterations do occur, different lithologies show different weathering trends. Those chemical alterations occur in proximity to secondary shears, suggesting fluid induced mass transfer.

  4. Nonextensive triplet in a geological faults system

    Science.gov (United States)

    de Freitas, D. B.; França, G. S.; Scherrer, T. M.; Vilar, C. S.; Silva, R.

    2013-05-01

    The San Andreas fault (SAF) in the USA is one of the most investigated self-organizing systems in Nature. In this paper, we studied some geophysical properties of the SAF system in order to analyze the behavior of earthquakes in the context of Tsallis's q-Triplet. To this end, we considered 134573 earthquake events in the magnitude interval 2\\leq m<8 , taken from the Southern Earthquake Data Center (SCEDC, 1932-2012). The values obtained (“q-Triplet”{}\\equiv\\{q_{\\textit{stat}},q_{\\textit{sen}},q_{\\textit{rel}}\\} ) reveal that the q_{\\textit{stat}} -Gaussian behavior of the aforementioned data exhibit long-range temporal correlations. Moreover, q_{\\textit{sen}} exhibits quasi-monofractal behavior with a Hurst exponent of 0.87.

  5. Nonextensive triplet in geological faults system

    CERN Document Server

    de Freitas, D B; Scheerer, T M; Vilar, C S; Silva, R

    2013-01-01

    The San Andreas fault (SAF) in the USA is one of the most investigated self-organizing systems in nature. In this paper, we studied some geophysical properties of the SAF system in order to analyze the behavior of earthquakes in the context of Tsallis's $q$--Triplet. To that end, we considered 134,573 earthquake events in magnitude interval $2\\leq m<8$, taken from the Southern Earthquake Data Center (SCEDC, 1932 - 2012). The values obtained ("$q$--Triplet"$\\equiv$$\\{$$q$$_{stat}$,$q$$_{sen}$,$q$$_{rel}$$\\}$) reveal that the $q_{stat}$--Gaussian behavior of the aforementioned data exhibit long-range temporal correlations. Moreover, $q_{sen}$ exhibits quasi-monofractal behavior with a Hurst exponent of 0.87.

  6. Using Precariously Balanced Rocks, Historic Records And Paleoseismology To Constrain Rupture Patterns And Rupture Potential Of The San Andreas And San Jacinto Faults In The Los Angeles Region

    Science.gov (United States)

    Grant Ludwig, L.; Brune, J. N.

    2010-12-01

    The San Andreas fault (SAF) has been identified as the likely source of a future damaging earthquake that could threaten millions of California residents, and the southern half of the fault has been identified as a likely candidate for rupture because it appears to be loaded with accumulated strain. Forecasts of future large earthquakes on the southern SAF and estimates of co-seismic slip depend critically on the slip rate and date of last rupture. The earliest historically documented rupture of the southern SAF occurred on December 8th and/or 21st, 1812 A.D., as recorded by early California missionaries, and confirmed by tree ring studies at Wrightwood, California. Prior to the tree ring study, the sequence of earthquakes in December 1812 was attributed to the Newport-Inglewood fault and/or another fault offshore of southern California, to explain the collapse of a church at Mission San Juan Capistrano and a tsunami near Mission Santa Barbara. Competing rupture models have been proposed to fit the sparse historic accounts of shaking recorded at the Missions, and sparse paleoseismic data from trenches excavated across the San Andreas and other southern California faults. Confirmation of proposed rupture patterns has been elusive because dates of surface ruptures observed in trenches at several locations along the SAF either cannot be resolved to 1812 due to uncertainty in radiocarbon dating, or preclude rupture. One possibility is that the 1812 earthquake ruptured both the SAF in Wrightwood and the northern San Jacinto fault in the Cajon Pass and San Bernardino Valley. Active traces of the faults are less than 2 km apart in Cajon Pass and it is well documented that ruptures can propagate between fault strands up to several kilometers apart. Here we propose that the distribution of fragile semi-precarious and precariously balanced rocks (PBRs) in the western San Bernardino Mountains is inconsistent with accepted rupture models for the 1812 earthquake. To better fit

  7. Uncertainties in slip-rate estimates for the Mission Creek strand of the southern San Andreas fault at Biskra Palms Oasis, southern California

    Science.gov (United States)

    Behr, W.M.; Rood, D.H.; Fletcher, K.E.; Guzman, N.; Finkel, R.; Hanks, T.C.; Hudnut, K.W.; Kendrick, K.J.; Platt, J.P.; Sharp, W.D.; Weldon, R.J.; Yule, J.D.

    2010-01-01

    This study focuses on uncertainties in estimates of the geologic slip rate along the Mission Creek strand of the southern San Andreas fault where it offsets an alluvial fan (T2) at Biskra Palms Oasis in southern California. We provide new estimates of the amount of fault offset of the T2 fan based on trench excavations and new cosmogenic 10Be age determinations from the tops of 12 boulders on the fan surface. We present three alternative fan offset models: a minimum, a maximum, and a preferred offset of 660 m, 980 m, and 770 m, respectively. We assign an age of between 45 and 54 ka to the T2 fan from the 10Be data, which is significantly older than previously reported but is consistent with both the degree of soil development associated with this surface, and with ages from U-series geochronology on pedogenic carbonate from T2, described in a companion paper by Fletcher et al. (this volume). These new constraints suggest a range of slip rates between ~12 and 22 mm/yr with a preferred estimate of ~14-17 mm/yr for the Mission Creek strand of the southern San Andreas fault. Previous studies suggested that the geologic and geodetic slip-rate estimates at Biskra Palms differed. We find, however, that considerable uncertainty affects both the geologic and geodetic slip-rate estimates, such that if a real discrepancy between these rates exists for the southern San Andreas fault at Biskra Palms, it cannot be demonstrated with available data. ?? 2010 Geological Society of America.

  8. Volatile fluxes through the Big Bend section of the San Andreas Fault, California: helium and carbon-dioxide systematics

    Science.gov (United States)

    Kulongoski, Justin T.; Hilton, David R.; Barry, Peter H.; Esser, Bradley K.; Hillegonds, Darren; Belitz, Kenneth

    2013-01-01

    To investigate the source of volatiles and their relationship to the San Andreas Fault System (SAFS), 18 groundwater samples were collected from wells near the Big Bend section of the SAFS in southern California and analyzed for helium and carbon abundance and isotopes. Concentrations of 4He, corrected for air-bubble entrainment, vary from 4.15 to 62.7 (× 10− 8) cm3 STP g− 1 H2O. 3He/4He ratios vary from 0.09 to 3.52 RA (where RA = air 3He/4He), consistent with up to 44% mantle helium in samples. A subset of 10 samples was analyzed for the major volatile phase (CO2) — the hypothesized carrier phase of the helium in the mantle–crust system: CO2/3He ratios vary from 0.614 to 142 (× 1011), and δ13C (CO2) values vary from − 21.5 to − 11.9‰ (vs. PDB). 3He/4He ratios and CO2 concentrations are highest in the wells located in the Mil Potrero and Cuddy valleys adjacent to the SAFS. The elevated 3He/4He ratios are interpreted to be a consequence of a mantle volatile flux though the SAFS diluted by radiogenic He produced in the crust. Samples with the highest 3He/4He ratios also had the lowest CO2/3He ratios. The combined helium isotope, He–CO2 elemental relationships, and δ13C (CO2) values of the groundwater volatiles reveal a mixture of mantle and deep crustal (metamorphic) fluid origins. The flux of fluids into the seismogenic zone at high hydrostatic pressure may cause fault rupture, and transfer volatiles into the shallow crust. We calculate an upward fluid flow rate of 147 mm a− 1 along the SAFS, up to 37 times higher than previous estimates (Kennedy et al., 1997). However, using newly identified characteristics of the SAFS, we calculate a total flux of 3He along the SAFS of 7.4 × 103 cm3 STP a− 1 (0.33 mol 3He a− 1), and a CO2 flux of 1.5 × 1013 cm3STP a− 1 (6.6 × 108 mol a− 1), ~ 1% of previous estimates. Lower fluxes along the Big Bend section of the SAFS suggest that the flux of mantle volatiles alone is insufficient to cause the

  9. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    isolation is based directly on the input/output s ignals applied for the fault detection. It is guaranteed that the fault group includes the fault that had occurred in the system. The second step is individual fault isolation in the fault group . Both types of isolation are obtained by applying dedicated......Active fault isolation of parametric faults in closed-loop MIMO system s are considered in this paper. The fault isolation consists of two steps. T he first step is group- wise fault isolation. Here, a group of faults is isolated from other pos sible faults in the system. The group-wise fault...

  10. Fuzzy fault diagnostic system based on fault tree analysis

    OpenAIRE

    Yang, Zong Xiao; Suzuki, Kazuhiko; Shimada, Yukiyasu; Sayama, Hayatoshi

    1995-01-01

    A method is presented for process fault diagnosis using information from fault tree analysis and uncertainty/imprecision of data. Fault tree analysis, which has been used as a method of system reliability/safety analysis, provides a procedure for identifying failures within a process. A fuzzy fault diagnostic system is constructed which uses the fuzzy fault tree analysis to represent a knowledge of the causal relationships in process operation and control system. The proposed method is applie...

  11. Fault management for data systems

    Science.gov (United States)

    Boyd, Mark A.; Iverson, David L.; Patterson-Hine, F. Ann

    1993-01-01

    Issues related to automating the process of fault management (fault diagnosis and response) for data management systems are considered. Substantial benefits are to be gained by successful automation of this process, particularly for large, complex systems. The use of graph-based models to develop a computer assisted fault management system is advocated. The general problem is described and the motivation behind choosing graph-based models over other approaches for developing fault diagnosis computer programs is outlined. Some existing work in the area of graph-based fault diagnosis is reviewed, and a new fault management method which was developed from existing methods is offered. Our method is applied to an automatic telescope system intended as a prototype for future lunar telescope programs. Finally, an application of our method to general data management systems is described.

  12. A New Estimate for Total Offset on the Southern San Andreas Fault: Implications for Cumulative Plate Boundary Shear in the Northern Gulf of California

    Science.gov (United States)

    Darin, M. H.; Dorsey, R. J.

    2012-12-01

    Development of a consistent and balanced tectonic reconstruction for the late Cenozoic San Andreas fault (SAF) in southern California has been hindered for decades by incompatible estimates of total dextral offset based on different geologic cross-fault markers. The older estimate of 240-270 km is based on offset fluvial conglomerates of the middle Miocene Mint Canyon and Caliente Formations west of the SAF from their presumed source area in the northern Chocolate Mountains NE of the SAF (Ehlig et al., 1975; Ehlert, 2003). The second widely cited offset marker is a distinctive Triassic megaporphyritic monzogranite that has been offset 160 ± 10 km between Liebre Mountain west of the SAF and the San Bernadino Mountains (Matti and Morton, 1993). In this analysis we use existing paleocurrent data and late Miocene clockwise rotation in the eastern Transverse Ranges (ETR) to re-assess the orientation of the piercing line used in the 240 km-correlation, and present a palinspastic reconstruction that satisfies all existing geologic constraints. Our reconstruction of the Mint Canyon piercing line reduces the original estimate of 240-270 km to 195 ± 15 km of cumulative right-lateral slip on the southern SAF (sensu stricto), which is consistent with other published estimates of 185 ± 20 km based on correlative basement terranes in the Salton Trough region. Our estimate of ~195 km is consistent with the lower estimate of ~160 km on the Mojave segment because transform-parallel extension along the southwestern boundary of the ETR during transrotation produces ~25-40 km of displacement that does not affect offset markers of the Liebre/San Bernadino correlation located northwest of the ETR rotating domain. Reconciliation of these disparate estimates places an important new constraint on the total plate boundary shear that is likely accommodated in the adjacent northern Gulf of California. Global plate circuit models require ~650 km of cumulative Pacific-North America (PAC

  13. Andreas Vesalius' 500th Anniversary: Initiation of the Superficial Facial System and Superficial Musculoaponeurotic System Concepts.

    Science.gov (United States)

    Brinkman, Romy J; Hage, J Joris

    2016-02-01

    Because of their relevance for liposuction and rhytidectomies, respectively, the superficial fascial system (SFS) and superficial musculoaponeurotic system (SMAS) have been thoroughly studied over the past decennia. Although it is well known that the SMAS concept was introduced by Tessier in 1974, it remains unknown who first properly described the stratum membranosum of the SFS. In light of the 500th birthday of Andreas Vesalius (1515-1564), we searched his 1543 masterwork De Humani Corporis Fabrica Libri Septem and related work for references to these structures. We found ample reference to both structures as the membrana carnosa (or fleshy membrane) in his works and concluded that Vesalius recognized the extension, nature, and functions of the stratum membranosum of the SFS, as well as its more musculous differentiation as the SMAS in the head and neck area, and the dartos in the perineogenital area. In doing so, Vesalius recorded most details of the SFS and SMAS concepts avant la lettre. PMID:26761152

  14. Near-Surface San Andreas Fault Location and Dip Near Woodside, California From Tomographic Vp, Vs, and Vp/Vs Ratios

    Science.gov (United States)

    Goldman, M.; Catchings, R.; Sickler, R. R.; Criley, C.; Prentice, C. S.

    2014-12-01

    The slip history of the San Andreas Fault (SAF) on the San Francisco peninsula is not well determined, and paleoseismic investigations to date yield inconsistent results, possibly because previous measurements were made on differing near-surface traces of the SAF. Furthermore, ground-shaking modeling requires accurate shallow-depth S-wave velocities across the fault zone and accurate fault dips; the existing Bay Area 3-D velocity models lack such measurements. To locate all near-surface traces of the SAF within 150 m of the 1906 surface rupture, to determine near-surface shear-wave velocities (VS30 to VS100), and to determine the fault dip, the USGS acquired a set of 300-m-long, high-resolution, P- and S-wave seismic imaging profiles across the SAF near Woodside, California, centered on the 1906 surface rupture zone. Sources (seisgun and hammer) and receivers (40-Hz P-wave and 4.5-Hz S-wave) were spaced at 3-m intervals. We developed independent P- and S-wave tomographic velocity models to depths of ~ 120 m (P-waves) and 80 m (S-waves). P-wave velocities vary widely from near the surface (Vp = 800 m/s, Vs = 250) to 100 m depth (Vp > 3000 m/s, Vs > 500 m/s). The 1906 surface rupture zone forms P- and S-wave low-velocity zones (Vp = 1600 to 1800 m/s; Vs = 250 to 350 m/s) within the fault zone relative to outside the fault zone (Vp = 2000 to 2200 m/s; Vs = 300 to 400 m/s). Vp/Vs ratios range from about 2.8 to about 5.7, with higher ratios on either side of the 1906 surface rupture zone and on the uphill (southwest) side. Southwest-dipping Vp/Vs contours suggest a 60o-southwest dip for one of the fault traces. However, a CDP reflection stack shows a near-vertical dip of the main 1906 rupture zone to 1.2 km depth, and the stack shows evidence for multiple fault traces. Collectively, these new data show a complex fault structure and highly variable velocities across the fault zone, which should aid paleoseismic investigations and improve existing ground-shaking models.

  15. Chemical and Isotopic Composition of Water and Gases From the SAFOD Wells: Implications to the Dynamics of the San Andreas Fault at Parkfield, California

    Science.gov (United States)

    Thordsen, J. J.; Evans, W. C.; Kharaka, Y. K.; Kennedy, B. M.; van Soest, M.

    2005-12-01

    To investigate the source of fluids within the San Andreas fault zone, we obtained downhole fluid samples from both the SAFOD pilot well (open hole at vertical depth of ~2.2 km) and the adjacent SAFOD main well, from open holes at depths of 1443-1470 m and 2540-2557 m. Each fluid sampling opportunity followed coring runs, which provided open holes at these depths, enabling formation fluid to enter the wells. Prior to coring, the drilling fluids were tagged with fluorescein and Rhodamine WT tracer dyes to allow for calculation of the contamination effects. We used an evacuated Kuster sampler and positive-displacement Westport samplers, that both allow for accurate determination of the dissolved gas concentrations. Chemical data and water-level measurements in the SAFOD pilot well and the shallower zone of SAFOD main well indicated that no significant amount of formation water was produced. Significant amounts of formation water, however, were produced from the deeper open hole of the SAFOD main well. The water level in the well rose ~60 m from completion of coring (October 1, 2004) to the first fluid sampling (April 13, 2005), when three samples were obtained, and rose ~12 m more by June 8, 2005, when an additional 4 samples were collected. Chemical data show that these samples are a mixture of formation water (75-80%) and the dye-tagged `KCl' drilling solution. High pH values (9.5-10.5) and high Ca concentrations indicate contamination from the cement used for casing the well. Mixing proportions and geochemical modeling, utilizing the tracer dyes and conservative solutes, are used to calculate the compositions of formation water. Results show a Na-Ca-Cl type water with a salinity of ~20,000 mg/L TDS, very low Mg (0.1 mg/L) and carbonate alkalinity (water from sedimentary rocks, such as oil field waters from California. The deepest samples from SAFOD main well are extremely gas-rich, with calculated in-situ gas pressures exceeding 50 bar. The gas composition is also

  16. Fault injection system for automatic testing system

    Institute of Scientific and Technical Information of China (English)

    王胜文; 洪炳熔

    2003-01-01

    Considering the deficiency of the means for confirming the attribution of fault redundancy in the re-search of Automatic Testing System(ATS) , a fault-injection system has been proposed to study fault redundancyof automatic testing system through compurison. By means of a fault-imbeded environmental simulation, thefaults injected at the input level of the software are under test. These faults may induce inherent failure mode,thus bringing about unexpected output, and the anticipated goal of the test is attained. The fault injection con-sists of voltage signal generator, current signal generator and rear drive circuit which are specially developed,and the ATS can work regularly by means of software simulation. The experimental results indicate that the faultinjection system can find the deficiency of the automatic testing software, and identify the preference of fault re-dundancy. On the other hand, some soft deficiency never exposed before can be identified by analyzing the tes-ting results.

  17. Subaru FATS (fault tracking system)

    Science.gov (United States)

    Winegar, Tom W.; Noumaru, Junichi

    2000-07-01

    The Subaru Telescope requires a fault tracking system to record the problems and questions that staff experience during their work, and the solutions provided by technical experts to these problems and questions. The system records each fault and routes it to a pre-selected 'solution-provider' for each type of fault. The solution provider analyzes the fault and writes a solution that is routed back to the fault reporter and recorded in a 'knowledge-base' for future reference. The specifications of our fault tracking system were unique. (1) Dual language capacity -- Our staff speak both English and Japanese. Our contractors speak Japanese. (2) Heterogeneous computers -- Our computer workstations are a mixture of SPARCstations, Macintosh and Windows computers. (3) Integration with prime contractors -- Mitsubishi and Fujitsu are primary contractors in the construction of the telescope. In many cases, our 'experts' are our contractors. (4) Operator scheduling -- Our operators spend 50% of their work-month operating the telescope, the other 50% is spent working day shift at the base facility in Hilo, or day shift at the summit. We plan for 8 operators, with a frequent rotation. We need to keep all operators informed on the current status of all faults, no matter the operator's location.

  18. Fault detection in photovoltaic systems

    OpenAIRE

    Nilsson, David

    2014-01-01

    This master’s thesis concerns three different areas in the field of fault detection in photovoltaic systems.Previous studies have concerned homogeneous systems with a large set of parameters being observed,while this study is focused on a more restrictive case. The first problem is to discover immediate faults occurring in solar panels. A new online algorithm is developed based on similarity measures with in a single installation. It performs reliably and is able to detect all significant fau...

  19. Is there a "blind" strike-slip fault at the southern end of the San Jacinto Fault system?

    Science.gov (United States)

    Tymofyeyeva, E.; Fialko, Y. A.

    2015-12-01

    We have studied the interseismic deformation at the southern end of the San Jacinto fault system using Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) data. To complement the continuous GPS measurements from the PBO network, we have conducted campaign-style GPS surveys of 19 benchmarks along Highway 78 in the years 2012, 2013, and 2014. We processed the campaign GPS data using GAMIT to obtain horizontal velocities. The data show high velocity gradients East of the surface trace of the Coyote Creek Fault. We also processed InSAR data from the ascending and descending tracks of the ENVISAT mission between the years 2003 and 2010. The InSAR data were corrected for atmospheric artifacts using an iterative common point stacking method. We combined average velocities from different look angles to isolate the fault-parallel velocity field, and used fault-parallel velocities to compute strain rate. We filtered the data over a range of wavelengths prior to numerical differentiation, to reduce the effects of noise and to investigate both shallow and deep sources of deformation. At spatial wavelengths less than 2km the strain rate data show prominent anomalies along the San Andreas and Superstition Hills faults, where shallow creep has been documented by previous studies. Similar anomalies are also observed along parts of the Coyote Creek Fault, San Felipe Fault, and an unmapped southern continuation of the Clark strand of the San Jacinto Fault. At wavelengths on the order of 20km, we observe elevated strain rates concentrated east of the Coyote Creek Fault. The long-wavelength strain anomaly east of the Coyote Creek Fault, and the localized shallow creep observed in the short-wavelength strain rate data over the same area suggest that there may be a "blind" segment of the Clark Fault that accommodates a significant portion of the deformation on the southern end of the San Jacinto Fault.

  20. Interaction Between Early San Andreas Strike-Slip Faulting and Extensional Tectonism in the Chocolate Mountains: A Prologue to Growth of the Salton Trough Along the Plate Boundary in Southern California

    Science.gov (United States)

    Powell, R. E.; Fleck, R. J.

    2008-12-01

    The Chocolate Mountains (CM) along the NE margin of the southern Salton Trough (ST) lie NE of the post-5- Ma San Andreas fault (SAF) and SW of the early and middle Miocene Clemens Well-Fenner-San Francisquito strand (CW-F-SF) of the SAF system. The CM are a highly extended terrain that evolved during the late Oligocene-middle Miocene and is bounded by the CW fault. Constrained by reconstruction of a compelling array of paleogeologic patterns, the approximately 300 km displacement on the SAF NW of the Garlock fault is distributed to the SE on the SAF (ca 160 km, 0 to 5 Ma), San Gabriel fault (ca 40 km, 0-5 to 12 Ma), and CW-F-SF fault (ca 100 km, 13 to 17-22 Ma). The youngest rocks yet shown to be offset 300 km in southern CA are basalts in the Diligencia and Plush Ranch formations, as young as 22 Ma. Lack of evidence for a large-displacement dextral fault in AZ on-trend with the CW fault requires the existence of a tectonic mechanism for absorbing its dextral displacement to the SE. Structure in the CM manifests late Oligocene-middle Miocene extensional tectonism that culminated in exhumation of Orocopia Schist by tectonic denudation. In its early stages, tectonism was accompanied by sedimentation and by voluminous magma-generation producing a batholithic-to-volcanic edifice. The principal structural feature is a complexly faulted, NW-trending array of en echelon antiforms that runs the length of the range and continues SE into AZ and NW into the Orocopia Mts. In the anticlinorium core, Orocopia Schist is intruded by a late Oligocene composite batholith of mafic to felsic plutons. A succession of tectonic plates separated by detachment faults overlies the schist and plutons. The structurally lowest fault is ductile and juxtaposes mylonite against the schist. Three higher faults, all brittle, vertically stack plates of (1) Mesozoic orthogneiss, (2) little deformed Triassic and Jurassic plutonic rocks, Proterozoic gneiss and anorthosite, and dacitic to rhyolitic late

  1. Wiring systems and fault finding

    CERN Document Server

    Scaddan, Brian

    1905-01-01

    This book deals with an area of practice which many students and non-electricians find particularly challenging. It explains how to interpret circuit diagrams, wiring systems and the principles and practice of testing and fault diagnosis. It will give the reader confidence to understand the principles of testing and to apply this knowledge to fault finding in electrical circuits.It is a handy reference for anybody who needs to be able to trace faults in circuits, whether in domestic, commercial or industrial settings. It will be a time-saver for all electricians, plumbers, heating engineers, t

  2. Implications of Microstructural Studies of the SAFOD Gouge for the Strength and Deformation Mechanisms in the Creeping Segment of the San Andreas Fault

    Science.gov (United States)

    Hadizadeh, J.; Gratier, J. L.; Mittempergher, S.; Renard, F.; Richard, J.; di Toro, G.; Babaie, H. A.

    2010-12-01

    The San Andreas Fault zone (SAF) in the vicinity of the San Andreas Fault Observatory at Depth (SAFOD)in central California is characterized by an average 21 mm/year aseismic creep and strain release through repeating Mmodels for the SAF? The SAFOD provides core samples and geophysical data including cores from two shear zones where the main borehole casing is deforming. The studies so far show a weak fault zone with about 200m of low-permeability damage zone without anomalous temperature or high fluid pressure (Zoback et al. EOS 2010). To answer the above questions, we studied core samples and thin sections ranging in measured depths (MD) from 3059m to 3991m including gouge from borehole casing deformation zones. The methods of study included high resolution scanning and transmission electron microscopy, cathodoluminescence imaging, X-ray fluorescence mapping, and energy dispersive X-ray spectroscopy. The microstructural and analytical data suggest that deformation is by a coupling of cataclastic flow and pressure solution accompanied by widespread alteration of feldspar to clay minerals and other neomineralizations. The clay contents of the gouge and streaks of serpentinite are not uniformly distributed, but weakness of the creeping segment is likely to be due to intrinsically low frictional strength of the fault material. This conclusion, which is based on the overall ratio of clay/non-clay constituents and the presence of talc in the actively deforming zones, is consistent with the 0.3-0.45 coefficient of friction for the drill cuttings tested by others. We also considered weakening by diffusion-accommodated grain boundary sliding. There are two main trends in the microstructural data that provide a basis for explaining the creep rate and seismic activity: 1. Clay content of the gouge including serpentinite and talc increases toward the 1-3m wide borehole casing deformation zones, which are expected to be deforming at above the average creep rate 2. Evidence of

  3. Late Quaternary slip history of the Mill Creek strand of the San Andreas fault in San Gorgonio Pass, southern California: The role of a subsidiary left-lateral fault in strand switching

    Science.gov (United States)

    Kendrick, Katherine J.; Matti, Jonathan; Mahan, Shannon

    2015-01-01

    The fault history of the Mill Creek strand of the San Andreas fault (SAF) in the San Gorgonio Pass region, along with the reconstructed geomorphology surrounding this fault strand, reveals the important role of the left-lateral Pinto Mountain fault in the regional fault strand switching. The Mill Creek strand has 7.1–8.7 km total slip. Following this displacement, the Pinto Mountain fault offset the Mill Creek strand 1–1.25 km, as SAF slip transferred to the San Bernardino, Banning, and Garnet Hill strands. An alluvial complex within the Mission Creek watershed can be linked to palinspastic reconstruction of drainage segments to constrain slip history of the Mill Creek strand. We investigated surface remnants through detailed geologic mapping, morphometric and stratigraphic analysis, geochronology, and pedogenic analysis. The degree of soil development constrains the duration of surface stability when correlated to other regional, independently dated pedons. This correlation indicates that the oldest surfaces are significantly older than 500 ka. Luminescence dates of 106 ka and 95 ka from (respectively) 5 and 4 m beneath a younger fan surface are consistent with age estimates based on soil-profile development. Offset of the Mill Creek strand by the Pinto Mountain fault suggests a short-term slip rate of ∼10–12.5 mm/yr for the Pinto Mountain fault, and a lower long-term slip rate. Uplift of the Yucaipa Ridge block during the period of Mill Creek strand activity is consistent with thermochronologic modeled uplift estimates.

  4. A learning system for fault finding

    OpenAIRE

    Tunevi, Anders

    1989-01-01

    A learning system for fault finding has been constructed. This system contains many different types of knowledge, three ways to find faults and four ways to learn fault finding. The constructed learning system works for a class of fault finding problems. This class has been described in the paper. The developed system could be viewed as an architecture of a general learning system for fault finding. The system could also be used as a testbench of learning mechanisms. The experiences from this...

  5. Fault Tolerant Quantum Filtering and Fault Detection for Quantum Systems

    OpenAIRE

    Gao, Qing; Dong, Daoyi; Petersen, Ian R.

    2015-01-01

    This paper aims to determine the fault tolerant quantum filter and fault detection equation for a class of open quantum systems coupled to a laser field that is subject to stochastic faults. In order to analyze this class of open quantum systems, we propose a quantum-classical Bayesian inference method based on the definition of a so-called quantum-classical conditional expectation. It is shown that the proposed Bayesian inference approach provides a convenient tool to simultaneously derive t...

  6. Revealing a strike-slip plate boundary: Drill-bit seismic imaging of the San Andreas Fault at the SAFOD site

    Science.gov (United States)

    Taylor, Stewart Thomas

    2006-12-01

    The San Andreas Fault at the San Andreas Fault Observatory at Depth (SAFOD) near Parkfield, CA forms the contact between the Pacific and North American tectonic plates. The hypotheses tested in this dissertation are that this boundary (1) is not located beneath the currently recognized surface trace of the SAF, (2) is not composed of a single active strand, but at least two overlapping, positive and negative flower structures, and (3) has juxtaposed, severely folded, and then buried Tertiary to pre-Cretaceous strata not previously known to exist in the Parkfield area. These hypotheses were tested through the construction, analysis, and interpretation of a new type of drill-bit seismic reflection imaging at the SAFOD drill site. Drill-bit seismic (DBS) imaging uses the drill bit as a seismic source. Previous DBS experiments have used geophone receiver arrays laid on the earth's surface. At SAFOD, a vertical receiver array supplemented a surface receiver array, to record the Stage 1 drilling of SAFOD well which was completed in 2004. This dissertation expands the DBS method by utilizing both the vertical and surface arrays to record the drill bit vibrations and produce two types of reverse vertical seismic profiles. A major portion of this dissertation includes research and development of DBS data signal processing techniques for industrial applications and the special case of the SAFOD observations. These observations include downhole geophone recordings which represent a new approach not previously reported in the seismic reflection literature. The application of algorithms produced by these studies has resulted in improved methods for estimating the drill bit seismic source signature. These methods also determine optimal deconvolution operators for DBS signals which produce estimates of the "pilot signal". It is shown that processing of DBS data is possible without drill string pilot accelerometers. This allows more economic deployment of equipment at the drill

  7. Tremor reveals stress shadowing, deep postseismic creep, and depth-dependent slip recurrence on the lower-crustal San Andreas fault near Parkfield

    Science.gov (United States)

    Shelly, David R.; Johnson, Kaj M.

    2011-01-01

    The 2003 magnitude 6.5 San Simeon and the 2004 magnitude 6.0 Parkfield earthquakes induced small, but significant, static stress changes in the lower crust on the central San Andreas fault, where recently detected tectonic tremor sources provide new constraints on deep fault creep processes. We find that these earthquakes affect tremor rates very differently, consistent with their differing transferred static shear stresses. The San Simeon event appears to have cast a "stress shadow" north of Parkfield, where tremor activity was stifled for 3-6 weeks. In contrast, the 2004 Parkfield earthquake dramatically increased tremor activity rates both north and south of Parkfield, allowing us to track deep postseismic slip. Following this event, rates initially increased by up to two orders of magnitude for the relatively shallow tremor sources closest to the rupture, with activity in some sources persisting above background rates for more than a year. We also observe strong depth dependence in tremor recurrence patterns, with shallower sources generally exhibiting larger, less-frequent bursts, possibly signaling a transition toward steady creep with increasing temperature and depth. Copyright 2011 by the American Geophysical Union.

  8. Magnetic stratigraphy and a test for block rotation of sedimentary rocks within the San Andreas fault zone, Mecca Hills, southeastern California

    Science.gov (United States)

    Chang, Shih-Bin R.; Allen, Clarence R.; Kirschvink, Joseph L.

    1987-01-01

    A 500-m section of the Palm Spring Formation in the southern Mecca Hills, located within the San Andreas fault zone in southeastern California, has been paleomagnetically sampled to determine possible tectonic rotation in this area and to establish time-stratigraphic control. This work was partly stimulated by the fact that 80 km farther south, previous studies demonstrated 35° of postdepositional rotation in the Palm Spring Formation of the Vallecito-Fish Creek basin east of the Elsinore fault. Several lines of evidence suggest that hematite is the main magnetic carrier of the Mecca Hills samples. Large anhedral hematite grains observed in magnetic extracts and a positive fold test imply a detrital origin of the remanence. The polarity reversal patterns, together with earlier vertebrate paleontologic studies, restrict the time span for deposition of this unit to the middle-late Matuyama chron (2.0-0.75 myr ago), thus of uppermost Pliocene and early Pleistocene age. Characteristic directions of best least-squares fit for 73 samples suggest little or no overall rotation, despite the severe late Quaternary tectonic activity demonstrated by the intense deformation of these strata.

  9. S-wave triggering of tremor beneath the Parkfield, California, section of the San Andreas fault by the 2011 Tohoku, Japan earthquake: observations and theory

    Science.gov (United States)

    Hill, David P.; Peng, Zhigang; Shelly, David R.; Aiken, Chastity

    2013-01-01

    The dynamic stresses that are associated with the energetic seismic waves generated by the Mw 9.0 Tohoku earthquake off the northeast coast of Japan triggered bursts of tectonic tremor beneath the Parkfield section of the San Andreas fault (SAF) at an epicentral distance of ∼8200  km. The onset of tremor begins midway through the ∼100‐s‐period S‐wave arrival, with a minor burst coinciding with the SHSH arrival, as recorded on the nearby broadband seismic station PKD. A more pronounced burst coincides with the Love arrival, followed by a series of impulsive tremor bursts apparently modulated by the 20‐ to 30‐s‐period Rayleigh wave. The triggered tremor was located at depths between 20 and 30 km beneath the surface trace of the fault, with the burst coincident with the S wave centered beneath the fault 30 km northwest of Parkfield. Most of the subsequent activity, including the tremor coincident with the SHSH arrival, was concentrated beneath a stretch of the fault extending from 10 to 40 km southeast of Parkfield. The seismic waves from the Tohoku epicenter form a horizontal incidence angle of ∼14°, with respect to the local strike of the SAF. Computed peak dynamic Coulomb stresses on the fault at tremor depths are in the 0.7–10 kPa range. The apparent modulation of tremor bursts by the small, strike‐parallel Rayleigh‐wave stresses (∼0.7  kPa) is likely enabled by pore pressure variations driven by the Rayleigh‐wave dilatational stress. These results are consistent with the strike‐parallel dynamic stresses (δτs) associated with the S, SHSH, and surface‐wave phases triggering small increments of dextral slip on the fault with a low friction (μ∼0.2). The vertical dynamic stresses δτd do not trigger tremor with vertical or oblique slip under this simple Coulomb failure model.

  10. Earthquake Recurrence and Slip Over the Past 4 - 5 events on the Southern Santa Cruz Mountains Section of the San Andreas Fault

    Science.gov (United States)

    Streig, A. R.; Dawson, T. E.; Weldon, R. J.

    2011-12-01

    The Santa Cruz Mountains section (SAS) of the San Andreas fault last ruptured during the 1906 earthquake, an event that ruptured about 470 km, from Point Arena to San Juan Bautista, California. Paleoseismic studies on the SAS at the Grizzly Flat (GF) and Arano Flat - Mill Creek (AF) paleoseismic sites provide evidence of 1906 surface deformation, but have yielded differing records of prehistoric surface-fault ruptures. GF is located 14 km northwest of the AF site and records one 17th Century earthquake dated between 1632-1659 (Schwartz et al., 1996). The record at AF site records a younger penultimate earthquake between AD 1711 - 1770, with a third event between AD 1660-1670 (Fumal, in review). The AF sites suggest nine earthquakes in the past ~1000 years, and an average recurrence interval of 105 years over the past 1,000 years (Fumal et al., 2003). The Hazel Dell site is located approximately 9.5 km north of AF, between the AF and GF sites. This site has yielded good evidence of the most recent earthquake the 1906 surface rupture (E1), and 3 to 4 earlier events, including new evidence for two mid 1800's earthquakes. Evidence for the penultimate event, E2, is expressed as upward fault terminations within a massive sand infilling a topographic low. This sand infilled a depression formed by the pre-penultimate earthquake, E3. We identified milled wood stratigraphically below the pre-penultimate earthquake horizon, which suggests that surface rupturing earthquakes E2 and E3 occurred after deposition of the milled wood stratigraphic unit. Lumber harvesting began in the area around 1832, which suggests that earthquakes E2 and E3 are historical. Based on the presence of milled wood, the stratigraphic record at Hazel Dell appears more complete during the early historical period than at the AF and GF sites. These new event data for the SAS suggest more frequent surface rupturing earthquakes within historical time than previously recognized. We present a preliminary short

  11. Time-dependent model of aseismic slip on the central San Andreas Fault from InSAR time series and repeating earthquakes

    Science.gov (United States)

    Khoshmanesh, M.; Shirzaei, M.; Nadeau, R. M.

    2015-09-01

    The Central segment of San Andreas Fault (CSAF) is characterized by a nearly continuous right-lateral aseismic slip. However, observations of the creep rate obtained using small characteristically repeating earthquakes (CREs) show pulses of creep along the CSAF, which may indicate spatially and temporally variable seismic hazard along the CSAF. Therefore, the goal of this study is to obtain a high-resolution time-dependent model of creep along the CSAF to examine this hypothesis. To this end, we apply a time-dependent creep modeling approach, which combines interferometric synthetic aperture radar (InSAR) surface deformation time series and observations of fault creep obtained from CREs. The SAR data set includes C band scenes acquired by the ERS-2 and Envisat satellites between 2003 and 2011. The resulting creep rate distribution implies a peak rate up to 32 mm/yr along the central part of the CSAF. Afterslip due to the 2004 Parkfield earthquake on the southeastern segment of the CSAF is also manifest in the model, and there is clear evidence of creep pulsing along strike and depth of the CSAF. Estimated annual rate of slip deficit accumulation is equivalent to a magnitude 5.6-5.7 earthquake. Taking advantage of the time-dependence of our model, we also refine the scaling relationship, which associates the released seismic moment due to a CRE event with the amount of creep on the fault, surrounding the CRE patches. This study provides the first kinematic model of creep pulsing, constrained using geodetic and seismic data, which can enhance time-dependent seismic hazard maps and improve earthquake operational forecast models.

  12. Transient Faults in Computer Systems

    Science.gov (United States)

    Masson, Gerald M.

    1993-01-01

    A powerful technique particularly appropriate for the detection of errors caused by transient faults in computer systems was developed. The technique can be implemented in either software or hardware; the research conducted thus far primarily considered software implementations. The error detection technique developed has the distinct advantage of having provably complete coverage of all errors caused by transient faults that affect the output produced by the execution of a program. In other words, the technique does not have to be tuned to a particular error model to enhance error coverage. Also, the correctness of the technique can be formally verified. The technique uses time and software redundancy. The foundation for an effective, low-overhead, software-based certification trail approach to real-time error detection resulting from transient fault phenomena was developed.

  13. Potential field Modeling of the 3-D Geologic Structure of the San Andreas Fault Observatory at Depth (SAFOD) at Parkfield, California

    Science.gov (United States)

    McPhee, D. K.

    2003-12-01

    Gravity and magnetic data, along with other geophysical and geological constraints, are used to develop 2-D models that we use to characterize the 3-D geological structure of the San Andreas fault (SAF) zone in the vicinity of SAFOD near Parkfield, CA. The gravity data, reduced to isostatic anomalies, comprise a compilation of three different data sets with a maximum of 1.6 km grid spacing for the scattered data and closely spaced ( ˜40 m) stations along one SW-NE profile crossing the SAFOD pilot hole. Aeromagnetic data were flown at a nominal 300 m above the terrain along SW-NE flight lines perpendicular to the San Andreas Fault. Data were recorded at ˜50 m spacing along flight lines approximately 800 m apart. Ground magnetic data recorded every 5 m along lines ˜300 m apart cover a 3 x 5 km area surrounding the SAFOD pilot hole. Previous modeling showed that magnetic granitic basement rocks southwest of the SAF are divided by an inferred steep fault sub-parallel to the SAF. We compute 2-D crustal models along 5 km-long southwest-northeast profiles, one of which extends through the SAFOD pilot hole near and along the high-resolution seismic refraction/reflection survey completed in 1998 (Catchings et al., 2002). Our models are constrained by pilot hole measurements, where we see a boundary between sediment and granitic basement at ˜770 m and an order of magnitude increase in magnetic susceptibility at ˜1400 m, possibly the same depth at which the SW dipping Buzzard Canyon Fault intersects the pilot hole. Regional gravity, magnetic and geologic data indicate two very distinct basement blocks separated by a steeply dipping SAF. The shallowly dipping sedimentary section SW of the SAF coincides with the low velocity zone observed with seismic measurements. Shallow slivers of magnetic sandstone on the NE side of the SAF explain higher frequency features in the magnetic data. In addition, we show a flat lying, tabular body of serpentinite sandwiched between 2 blocks

  14. A Laboratory Earthquake‐Based Stochastic Seismic Source Generation Algorithm for Strike‐Slip Faults and its Application to the Southern San Andreas Fault

    OpenAIRE

    Siriki, Hemanth; Bhat, Harsha S.; Lu, Xiao; Krishnan, Swaminathan

    2015-01-01

    There is a sparse number of credible source models available from large‐magnitude past earthquakes. A stochastic source‐model‐generation algorithm thus becomes necessary for robust risk quantification using scenario earthquakes. We present an algorithm that combines the physics of fault ruptures as imaged in laboratory earthquakes with stress estimates on the fault constrained by field observations to generate stochastic source models for large‐magnitude (M_w 6.0–8.0) strike‐slip earthquakes....

  15. Soft Computing Approaches To Fault Tolerant Systems

    Directory of Open Access Journals (Sweden)

    Neeraj Prakash Srivastava

    2014-05-01

    Full Text Available We present in this paper as an introduction to soft computing techniques for fault tolerant systems and the terminology with different ways of achieving fault tolerance. The paper focuses on the problem of fault tolerance using soft computing techniques. The fundamentals of soft computing approaches and its type with introduction of fault tolerance are discussed. The main objective is to show how to implement soft computing approaches for fault detection, isolation and identification. The paper contains details about soft computing application with an application of wireless sensor network as fault tolerant system.

  16. Zipper Faults

    Science.gov (United States)

    Platt, J. P.; Passchier, C. W.

    2015-12-01

    Intersecting simultaneously active pairs of faults with different orientations and opposing slip sense ("conjugate faults") present geometrical and kinematic problems. Such faults rarely offset each other, even when they have displacements of many km. A simple solution to the problem is that the two faults merge, either zippering up or unzippering, depending on the relationship between the angle of intersection and the slip senses. A widely recognized example of this is the so-called blind front developed in some thrust belts, where a backthrust branches off a decollement surface at depth. The decollement progressively unzippers, so that its hanging wall becomes the hanging wall of the backthrust, and its footwall becomes the footwall of the active decollement. The opposite situation commonly arises in core complexes, where conjugate low-angle normal faults merge to form a single detachment; in this case the two faults zipper up. Analogous situations may arise for conjugate pairs of strike-slip faults. We present kinematic and geometrical analyses of the Garlock and San Andreas faults in California, the Najd fault system in Saudi Arabia, the North and East Anatolian faults, the Karakoram and Altyn Tagh faults in Tibet, and the Tonale and Guidicarie faults in the southern Alps, all of which appear to have undergone zippering over distances of several tens to hundreds of km. The zippering process may produce complex and significant patterns of strain and rotation in the surrounding rocks, particularly if the angle between the zippered faults is large. A zippering fault may be inactive during active movement on the intersecting faults, or it may have a slip rate that differs from either fault. Intersecting conjugate ductile shear zones behave in the same way on outcrop and micro-scales.

  17. Paleoearthquakes on the southern San Andreas Fault, Wrightwood, California, 3000 to 1500 B.C.: A new method for evaluating paleoseismic evidence and earthquake horizons

    Science.gov (United States)

    Scharer, K.M.; Weldon, R.J., II; Fumal, T.E.; Biasi, G.P.

    2007-01-01

    We present evidence of 11-14 earthquakes that occurred between 3000 and 1500 B.C. on the San Andreas fault at the Wrightwood paleoseismic site. Earthquake evidence is presented in a novel form in which we rank (high, moderate, poor, or low) the quality of all evidence of ground deformation, which are called "event indicators." Event indicator quality reflects our confidence that the morphologic and sedimentologic evidence can be attributable to a ground-deforming earthquake and that the earthquake horizon is accurately identified by the morphology of the feature. In four vertical meters of section exposed in ten trenches, we document 316 event indicators attributable to 32 separate stratigraphic horizons. Each stratigraphic horizon is evaluated based on the sum of rank (Rs), maximum rank (Rm), average rank (Ra), number of observations (Obs), and sum of higher-quality event indicators (Rs>1). Of the 32 stratigraphic horizons, 14 contain 83% of the event indicators and are qualified based on the number and quality of event indicators; the remaining 18 do not have satisfactory evidence for further consideration. Eleven of the 14 stratigraphic horizons have sufficient number and quality of event indicators to be qualified as "probable" to "very likely" earthquakes; the remaining three stratigraphic horizons are associated with somewhat ambiguous features and are qualified as "possible" earthquakes. Although no single measurement defines an obvious threshold for designation as an earthquake horizon, Rs, Rm, and Rs>1 correlate best with the interpreted earthquake quality. Earthquake age distributions are determined from radio-carbon ages of peat samples using a Bayesian approach to layer dating. The average recurrence interval for the 10 consecutive and highest-quality earthquakes is 111 (93-131) years and individual intervals are ??50% of the average. With comparison with the previously published 14-15 earthquake record between A.D. 500 and present, we find no evidence

  18. Synthesis of Fault-Tolerant Embedded Systems

    DEFF Research Database (Denmark)

    Eles, Petru; Izosimov, Viacheslav; Pop, Paul; Peng, Zebo

    This work addresses the issue of design optimization for fault- tolerant hard real-time systems. In particular, our focus is on the handling of transient faults using both checkpointing with rollback recovery and active replication. Fault tolerant schedules are generated based on a conditional...... process graph representation. The formulated system synthesis approaches decide the assignment of fault-tolerance policies to processes, the optimal placement of checkpoints and the mapping of processes to processors, such that multiple transient faults are tolerated, transparency requirements are...

  19. Multiple Fault Isolation in Redundant Systems

    Science.gov (United States)

    Shakeri, M.; Pattipati, Krishna R.; Raghavan, V.; Patterson-Hine, Ann; Iverson, David L.

    1997-01-01

    We consider the problem of sequencing tests to isolate multiple faults in redundant (fault-tolerant) systems with minimum expected testing cost (time). It can be shown that single faults and minimal faults, i.e., minimum number of failures with a failure signature different from the union of failure signatures of individual failures, together with their failure signatures, constitute the necessary information for fault diagnosis in redundant systems. In this paper, we develop an algorithm to find all the minimal faults and their failure signatures. Then, we extend the Sure diagnostic strategies [1] of our previous work to diagnose multiple faults in redundant systems. The proposed algorithms and strategies are illustrated using several examples.

  20. From fault classification to fault tolerance for multi-agent systems

    CERN Document Server

    Potiron, Katia; Taillibert, Patrick

    2013-01-01

    Faults are a concern for Multi-Agent Systems (MAS) designers, especially if the MAS are built for industrial or military use because there must be some guarantee of dependability. Some fault classification exists for classical systems, and is used to define faults. When dependability is at stake, such fault classification may be used from the beginning of the system's conception to define fault classes and specify which types of faults are expected. Thus, one may want to use fault classification for MAS; however, From Fault Classification to Fault Tolerance for Multi-Agent Systems argues that

  1. Fault isolability conditions for linear systems with additive faults

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2006-01-01

    In this paper, we shall show that an unlimited number of additive single faults can be isolated under mild conditions if a general isolation scheme is applied. Multiple faults are also covered. The approach is algebraic and is based on a set representation of faults, where all faults within a set...... can occur simultaneously, whereas faults belonging to different fault sets appear disjoint in time. The proposed fault detection and isolation (FDI) scheme consists of three steps. A fault detection (FD) step is followed by a fault set isolation (FSI) step. Here the fault set is isolated wherein the...... faults have occurred. The last step is a fault isolation (FI) of the faults occurring in a specific fault set, i.e. equivalent with the standard FI step....

  2. Middleware Fault Tolerance Support for the BOSS Embedded Operating System

    OpenAIRE

    Afonso, Francisco; Carlos A. Silva; Montenegro, Sérgio; Tavares, Adriano

    2006-01-01

    Critical embedded systems need a dependable operating system and application. Despite all efforts to prevent and remove faults in system development, residual software faults usually persist. Therefore, critical systems need some sort of fault tolerance to deal with these faults and also with hardware faults at operation time. This work proposes fault-tolerant support mechanisms for the BOSS embedded operating system, based on the application of proven fault tolerance strategies by middlew...

  3. Social vulnerability analysis of earthquake risk using HAZUS-MH losses from a M7.8 scenario earthquake on the San Andreas fault

    Science.gov (United States)

    Noriega, G. R.; Grant Ludwig, L.

    2010-12-01

    Natural hazards research indicates earthquake risk is not equitably distributed. Demographic differences are significant in determining the risks people encounter, whether and how they prepare for disasters, and how they fare when disasters occur. In this study, we analyze the distribution of economic and social losses in all 88 cities of Los Angeles County from the 2008 ShakeOut scenario earthquake. The ShakeOut scenario earthquake is a scientifically plausible M 7.8 scenario earthquake on the San Andreas fault that was developed and applied for regional earthquake preparedness planning and risk mitigation from a compilation of collaborative studies and findings by the 2007 Working Group on California Earthquake Probabilities (WGCEP). The scenario involved 1) developing a realistic scenario earthquake using the best available and most recent earthquake research findings, 2) estimation of physical damage, 3) estimation of social impact of the earthquake, and 4) identifying changes that will help to prevent a catastrophe due to an earthquake. Estimated losses from this scenario earthquake include 1,800 deaths and $213 billion dollars in economic losses. We use regression analysis to examine the relationship between potential city losses due to the ShakeOut scenario earthquake and the cities' demographic composition. The dependent variables are economic and social losses calculated in HAZUS-MH methodology for the scenario earthquake. The independent variables -median household income, tenure and race/ethnicity- have been identified as indicators of social vulnerability to natural disasters (Mileti, 1999; Cutter, 2006; Cutter & Finch, 2008). Preliminary Ordinary Least Squares (OLS) regression analysis of economic losses on race/ethnicity, income and tenure, indicates that cities with lower Hispanic population are associated with lower economic losses. Cities with higher Hispanic population are associated with higher economic losses, though this relationship is

  4. Active fault detection in MIMO systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    from auxiliary input to residual outputs. The analysis is based on a singular value decomposition of these transfer functions Based on this analysis, it is possible to design auxiliary input as well as design of the associated residual vector with respect to every single parametric fault in the system......The focus in this paper is on active fault detection (AFD) for MIMO systems with parametric faults. The problem of design of auxiliary inputs with respect to detection of parametric faults is investigated. An analysis of the design of auxiliary inputs is given based on analytic transfer functions...

  5. Fault system polarity: A matter of chance?

    Science.gov (United States)

    Schöpfer, Martin; Childs, Conrad; Manzocchi, Tom; Walsh, John; Nicol, Andy; Grasemann, Bernhard

    2015-04-01

    Many normal fault systems and, on a smaller scale, fracture boudinage exhibit asymmetry so that one fault dip direction dominates. The fraction of throw (or heave) accommodated by faults with the same dip direction in relation to the total fault system throw (or heave) is a quantitative measure of fault system asymmetry and termed 'polarity'. It is a common belief that the formation of domino and shear band boudinage with a monoclinic symmetry requires a component of layer parallel shearing, whereas torn boudins reflect coaxial flow. Moreover, domains of parallel faults are frequently used to infer the presence of a common décollement. Here we show, using Distinct Element Method (DEM) models in which rock is represented by an assemblage of bonded circular particles, that asymmetric fault systems can emerge under symmetric boundary conditions. The pre-requisite for the development of domains of parallel faults is however that the medium surrounding the brittle layer has a very low strength. We demonstrate that, if the 'competence' contrast between the brittle layer and the surrounding material ('jacket', or 'matrix') is high, the fault dip directions and hence fault system polarity can be explained using a random process. The results imply that domains of parallel faults are, for the conditions and properties used in our models, in fact a matter of chance. Our models suggest that domino and shear band boudinage can be an unreliable shear-sense indicator. Moreover, the presence of a décollement should not be inferred on the basis of a domain of parallel faults only.

  6. Fault analysis of multichannel spacecraft power systems

    Science.gov (United States)

    Dugal-Whitehead, Norma R.; Lollar, Louis F.

    1990-01-01

    The NASA Marshall Space Flight Center proposes to implement computer-controlled fault injection into an electrical power system breadboard to study the reactions of the various control elements of this breadboard. Elements under study include the remote power controllers, the algorithms in the control computers, and the artificially intelligent control programs resident in this breadboard. To this end, a study of electrical power system faults is being performed to yield a list of the most common power system faults. The results of this study will be applied to a multichannel high-voltage DC spacecraft power system called the large autonomous spacecraft electrical power system (LASEPS) breadboard. The results of the power system fault study and the planned implementation of these faults into the LASEPS breadboard are described.

  7. Explaining the current geodetic field with geological models: A case study of the Haiyuan fault system

    Science.gov (United States)

    Daout, S.; Jolivet, R.; Lasserre, C.; Doin, M. P.; Barbot, S.; Peltzer, G.; Tapponnier, P.

    2015-12-01

    Oblique convergence across Tibet leads to slip partitioning with the co-existence of strike-slip, normal and thrust motion in major fault systems. While such complexity has been shown at the surface, the question is to understand how faults interact and accumulate strain at depth. Here, we process InSAR data across the central Haiyuan restraining bend, at the north-eastern boundary of the Tibetan plateau and show that the surface complexity can be explained by partitioning of a uniform deep-seated convergence rate. We construct a time series of ground deformation, from Envisat radar data spanning from 2001-2011 period, across a challenging area because of the high jump in topography between the desert environment and the plateau. To improve the signal-to-noise ratio, we used the latest Synthetic Aperture Radar interferometry methodology, such as Global Atmospheric Models (ERA Interim) and Digital Elevation Model errors corrections before unwrapping. We then developed a new Bayesian approach, jointly inverting our InSAR time series together with published GPS displacements. We explore fault system geometry at depth and associated slip rates and determine a uniform N86±7E° convergence rate of 8.45±1.4 mm/yr across the whole fault system with a variable partitioning west and east of a major extensional fault-jog. Our 2D model gives a quantitative understanding of how crustal deformation is accumulated by the various branches of this thrust/strike-slip fault system and demonstrate the importance of the geometry of the Haiyuan Fault, controlling the partitioning or the extrusion of the block motion. The approach we have developed would allow constraining the low strain accumulation along deep faults, like for example for the blind thrust faults or possible detachment in the San Andreas "big bend", which are often associated to a poorly understood seismic hazard.

  8. Creep, compaction and the weak rheology of major faults

    Science.gov (United States)

    Sleep, N.H.; Blanpied, M.L.

    1992-01-01

    Field and laboratory observations suggest that the porosity within fault zones varies over earthquake cycles so that fluid pressure is in long-term equilibrium with hydrostatic fluid pressure in the country rock. Between earthquakes, ductile creep compacts the fault zone, increasing fluid pressure, and finally allowing frictional failure at relatively low shear stress. Earthquake faulting restores porosity and decreases fluid pressure to below hydrostatic. This mechanism may explain why major faults, such as the San Andreas system, are weak.

  9. Software fault tolerance in computer operating systems

    Science.gov (United States)

    Iyer, Ravishankar K.; Lee, Inhwan

    1994-01-01

    This chapter provides data and analysis of the dependability and fault tolerance for three operating systems: the Tandem/GUARDIAN fault-tolerant system, the VAX/VMS distributed system, and the IBM/MVS system. Based on measurements from these systems, basic software error characteristics are investigated. Fault tolerance in operating systems resulting from the use of process pairs and recovery routines is evaluated. Two levels of models are developed to analyze error and recovery processes inside an operating system and interactions among multiple instances of an operating system running in a distributed environment. The measurements show that the use of process pairs in Tandem systems, which was originally intended for tolerating hardware faults, allows the system to tolerate about 70% of defects in system software that result in processor failures. The loose coupling between processors which results in the backup execution (the processor state and the sequence of events occurring) being different from the original execution is a major reason for the measured software fault tolerance. The IBM/MVS system fault tolerance almost doubles when recovery routines are provided, in comparison to the case in which no recovery routines are available. However, even when recovery routines are provided, there is almost a 50% chance of system failure when critical system jobs are involved.

  10. Testing Distributed ABS System with Fault Injection

    Science.gov (United States)

    Trawczyński, Dawid; Sosnowski, Janusz; Gawkowski, Piotr

    The paper deals with the problem of adapting software implemented fault injection technique (SWIFI) to evaluate dependability of reactive microcontroller systems. We present an original methodology of disturbing controller operation and analyzing fault effects taking into account reactions of the controlled object and the impact of the system environment. Faults can be injected randomly (in space and time) or targeted at the most sensitive elements of the controller to check it at high stresses. This approach allows identifying rarely encountered problems, usually missed in classical approaches. The developed methodology has been used successfully to verify dependability of ABS system. Experimental results are commented in the paper.

  11. Fault detection and fault-tolerant control for nonlinear systems

    CERN Document Server

    Li, Linlin

    2016-01-01

    Linlin Li addresses the analysis and design issues of observer-based FD and FTC for nonlinear systems. The author analyses the existence conditions for the nonlinear observer-based FD systems to gain a deeper insight into the construction of FD systems. Aided by the T-S fuzzy technique, she recommends different design schemes, among them the L_inf/L_2 type of FD systems. The derived FD and FTC approaches are verified by two benchmark processes. Contents Overview of FD and FTC Technology Configuration of Nonlinear Observer-Based FD Systems Design of L2 nonlinear Observer-Based FD Systems Design of Weighted Fuzzy Observer-Based FD Systems FTC Configurations for Nonlinear Systems< Application to Benchmark Processes Target Groups Researchers and students in the field of engineering with a focus on fault diagnosis and fault-tolerant control fields The Author Dr. Linlin Li completed her dissertation under the supervision of Prof. Steven X. Ding at the Faculty of Engineering, University of Duisburg-Essen, Germany...

  12. Energy-efficient fault-tolerant systems

    CERN Document Server

    Mathew, Jimson; Pradhan, Dhiraj K

    2013-01-01

    This book describes the state-of-the-art in energy efficient, fault-tolerant embedded systems. It covers the entire product lifecycle of electronic systems design, analysis and testing and includes discussion of both circuit and system-level approaches. Readers will be enabled to meet the conflicting design objectives of energy efficiency and fault-tolerance for reliability, given the up-to-date techniques presented.

  13. Fault-tolerant parallel processing system

    Energy Technology Data Exchange (ETDEWEB)

    Harper, R.E.; Lala, J.H.

    1990-03-06

    This patent describes a fault tolerant processing system for providing processing operations, while tolerating f failures in the execution thereof. It comprises: at least (3f + 1) fault containment regions. Each of the regions includes a plurality of processors; network means connected to the processors and to the network means of the others of the fault containment regions; groups of one or more processors being configured to form redundant processing sites at least one of the groups having (2f + 1) processors, each of the processors of a group being included in a different one of the fault containment regions. Each network means of a fault containment region includes means for providing communication operations between the network means and the network means of the others of the fault containment regions, each of the network means being connected to each other network means by at lest (2f + 1) disjoint communication paths, a minimum of (f + 1) rounds of communication being provided among the network means of the fault containment regions in the execution of a the processing operation; and means for synchronizing the communication operations of the network means with the communications operations of the network means of the other fault containment regions.

  14. Fault Isolation in Object Oriented Control Systems

    OpenAIRE

    Larsson, Magnus; Klein, Inger; Lawesson, Dan; Nilsson, Ulf

    2000-01-01

    This article addresses the problem of fault propagation between software modules in a large-scale control system with object oriented architecture. There exists a conflict between object-oriented design goals such as encapsulation and modularity, and the possibility to suppress propagating error conditions. The propagation manifests itself as many irrelevant error messages, and hence causes problems for system operators and service personnel when attempting to isolate the real fault. We propo...

  15. Extreme multi-millennial slip rate variations on the Garlock fault, California: Strain super-cycles, potentially time-variable fault strength, and implications for system-level earthquake occurrence

    Science.gov (United States)

    Dolan, James F.; McAuliffe, Lee J.; Rhodes, Edward J.; McGill, Sally F.; Zinke, Robert

    2016-07-01

    Pronounced variations in fault slip rate revealed by new measurements along the Garlock fault have basic implications for understanding how faults store and release strain energy in large earthquakes. Specifically, dating of a series of 26.0+3.5/-2.5 m fault offsets with a newly developed infrared-stimulated luminescence method shows that the fault was slipping at >14.0+2.2/-1.8 mm /yr, approximately twice as fast as the long-term average rate, during a previously documented cluster of four earthquakes 0.5-2.0 ka. This elevated late Holocene rate must be balanced by periods of slow or no slip such as that during the ca. 3300-yr-long seismic lull preceding the cluster. Moreover, whereas a comparison of paleoseismic data and stress modeling results suggests that individual Garlock earthquakes may be triggered by periods of rapid San Andreas fault slip or very large-slip events, the "on-off" behavior of the Garlock suggests a longer-term mechanism that may involve changes in the rate of elastic strain accumulation on the fault over millennial time scales. This inference is consistent with most models of the geodetic velocity field, which yield slip-deficit rates that are much slower than the average latest Pleistocene-early Holocene (post-8-13 ka) Garlock slip rate of 6.5 ± 1.5 mm /yr. These observations indicate the occurrence of millennia-long strain "super-cycles" on the Garlock fault that may be associated with temporal changes in elastic strain accumulation rate, which may in turn be controlled by variations in relative strength of the various faults in the Garlock-San Andreas-Eastern California Shear Zone fault system and/or changes in relative plate motion rates.

  16. Robust Fault Diagnosis Design for Linear Multiagent Systems with Incipient Faults

    Directory of Open Access Journals (Sweden)

    Jingping Xia

    2015-01-01

    Full Text Available The design of a robust fault estimation observer is studied for linear multiagent systems subject to incipient faults. By considering the fact that incipient faults are in low-frequency domain, the fault estimation of such faults is proposed for discrete-time multiagent systems based on finite-frequency technique. Moreover, using the decomposition design, an equivalent conclusion is given. Simulation results of a numerical example are presented to demonstrate the effectiveness of the proposed techniques.

  17. Software engineering of fault tolerant systems

    CERN Document Server

    Pelliccione, P; Muccini, Henry

    2007-01-01

    In architecting dependable systems, what is required to improve the overall system robustness is fault tolerance. Many methods have been proposed to this end, the solutions are usually considered late during the design and implementation phases of the software life-cycle (e.g., Java and Windows NT exception handling), thus reducing the effectiveness error and fault handling. Since the system design typically models only normal behaviour of the system while ignoring exceptional ones, the implementation of the system is unable to handle abnormal events. Consequently, the system may fail in unexp

  18. Architecture of small-scale fault zones in the context of the Leinetalgraben Fault System

    Science.gov (United States)

    Reyer, Dorothea; Philipp, Sonja L.

    2010-05-01

    Understanding fault zone properties in different geological settings is important to better assess the development and propagation of faults. In addition this allows better evaluation and permeability estimates of potential fault-related geothermal reservoirs. The Leinetalgraben fault system provides an outcrop analogue for many fault zones in the subsurface of the North German Basin. The Leinetalgraben is a N-S-trending graben structure, initiated in the Jurassic, in the south of Lower Saxony and as such part of the North German Basin. The fault system was reactivated and inverted during Alpine compression in the Tertiary. This complex geological situation was further affected by halotectonics. Therefore we can find different types of fault zones, that is normal, reverse, strike-slip an oblique-slip faults, surrounding the major Leinetalgraben boundary faults. Here we present first results of structural geological field studies on the geometry and architecture of fault zones in the Leinetalgraben Fault System in outcrop-scale. We measured the orientations and displacements of 17 m-scale fault zones in limestone (Muschelkalk) outcrops, the thicknesses of their fault cores and damage zones, as well as the fracture densities and geometric parameters of the fracture systems therein. We also analysed the effects of rock heterogeneities, particularly stiffness variations between layers (mechanical layering) on the propagation of natural fractures and fault zones. The analysed fault zones predominantly show similar orientations as the major fault zones they surround. Other faults are conjugate or perpendicular to the major fault zones. The direction of predominant joint strike corresponds to the orientation of the fault zones in the majority of cases. The mechanical layering of the limestone and marlstone stratification obviously has great effects on fracture propagation. Already thin layers (mm- to cm-scale) of low stiffness - here marl - seem to suffice to change the

  19. Guaranteed Cost Fault-Tolerant Control for Networked Control Systems with Sensor Faults

    OpenAIRE

    Qixin Zhu; Kaihong Lu; Guangming Xie; Yonghong Zhu

    2015-01-01

    For the large scale and complicated structure of networked control systems, time-varying sensor faults could inevitably occur when the system works in a poor environment. Guaranteed cost fault-tolerant controller for the new networked control systems with time-varying sensor faults is designed in this paper. Based on time delay of the network transmission environment, the networked control systems with sensor faults are modeled as a discrete-time system with uncertain parameters. And the mode...

  20. Subtropical Storm Andrea

    Science.gov (United States)

    2007-01-01

    The circling clouds of an intense low-pressure system sat off the southeast coast of the United States on May 8, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image. By the following morning, the storm developed enough to be classified as a subtropical storm, a storm that forms outside of the tropics, but has many of the characteristics--hurricane-force winds, driving rains, low pressure, and sometimes an eye--of a tropical storm. Although it arrived several weeks shy of the official start of the hurricane season (June 1), Subtropical Storm Andrea became the first named storm of the 2007 Atlantic hurricane season. The storm has the circular shape of a tropical cyclone in this image, but lacks the tight organization seen in more powerful storms. By May 9, the storm's winds reached 75 kilometers per hour (45 miles per hour), and the storm was not predicted to get any stronger, said the National Hurricane Center. Though Subtropical Storm Andrea was expected to remain offshore, its strong winds and high waves pummeled coastal states, prompting a tropical storm watch. The winds fueled wild fires (marked with red boxes) in Georgia and Florida. The wind-driven flames generated thick plumes of smoke that concentrated in a gray-brown mass over Tampa Bay, Florida. Unfortunately for Georgia and Florida, which are experiencing moderate to severe drought, Subtropical Storm Andrea was not predicted to bring significant rain to the region right away, according to reports on the Washington Post Website.

  1. Transfer zones in listric normal fault systems

    Science.gov (United States)

    Bose, Shamik

    Listric normal faults are common in passive margin settings where sedimentary units are detached above weaker lithological units, such as evaporites or are driven by basal structural and stratigraphic discontinuities. The geometries and styles of faulting vary with the types of detachment and form landward and basinward dipping fault systems. Complex transfer zones therefore develop along the terminations of adjacent faults where deformation is accommodated by secondary faults, often below seismic resolution. The rollover geometry and secondary faults within the hanging wall of the major faults also vary with the styles of faulting and contribute to the complexity of the transfer zones. This study tries to understand the controlling factors for the formation of the different styles of listric normal faults and the different transfer zones formed within them, by using analog clay experimental models. Detailed analyses with respect to fault orientation, density and connectivity have been performed on the experiments in order to gather insights on the structural controls and the resulting geometries. A new high resolution 3D laser scanning technology has been introduced to scan the surfaces of the clay experiments for accurate measurements and 3D visualizations. Numerous examples from the Gulf of Mexico have been included to demonstrate and geometrically compare the observations in experiments and real structures. A salt cored convergent transfer zone from the South Timbalier Block 54, offshore Louisiana has been analyzed in detail to understand the evolutionary history of the region, which helps in deciphering the kinematic growth of similar structures in the Gulf of Mexico. The dissertation is divided into three chapters, written in a journal article format, that deal with three different aspects in understanding the listric normal fault systems and the transfer zones so formed. The first chapter involves clay experimental models to understand the fault patterns in

  2. Regional Fault Systems of Qaidam Basin and Adjacent Orogenic Belts

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The purpose of this paper is to analyze the regional fault systems of Qaidam basin and adjacent orogenic belts. Field investigation and seismic interpretation indicate that five regional fault systems occurred in the Qaidam and adjacent mountain belts, controlling the development and evolution of the Qaidam basin. These fault systems are: (1)north Qaidam-Qilian Mountain fault system; (2) south Qaidam-East Kunlun Mountain fault system; (3)Altun strike-slip fault system; (4)Elashan strike-slip fault system, and (5) Gansen-Xiaochaidan fault system. It is indicated that the fault systems controlled the orientation of the Qaidam basin, the formation and distribution of secondary faults within the basin,the migration of depocenters and the distribution of hydrocarbon accumulation belt.

  3. Observer-based Fault Detection and Isolation for Nonlinear Systems

    OpenAIRE

    Lootsma, T.F.

    2001-01-01

    With the rise in automation the increase in fault detectionand isolation & reconfiguration is inevitable. Interest in fault detection and isolation (FDI) for nonlinear systems has grown significantly in recent years. The design of FDI is motivated by the need for knowledge about occurring faults in fault-tolerant control systems (FTC systems). The idea of FTC systems is to detect, isolate, and handle faults in such a way that the systems can still perform in a required manner. One prefers...

  4. Fault tolerant filtering and fault detection for quantum systems driven by fields in single photon states

    Science.gov (United States)

    Gao, Qing; Dong, Daoyi; Petersen, Ian R.; Rabitz, Herschel

    2016-06-01

    The purpose of this paper is to solve the fault tolerant filtering and fault detection problem for a class of open quantum systems driven by a continuous-mode bosonic input field in single photon states when the systems are subject to stochastic faults. Optimal estimates of both the system observables and the fault process are simultaneously calculated and characterized by a set of coupled recursive quantum stochastic differential equations.

  5. Fault Detection for Shipboard Monitoring and Decision Support Systems

    DEFF Research Database (Denmark)

    Lajic, Zoran; Nielsen, Ulrik Dam

    2009-01-01

    In this paper a basic idea of a fault-tolerant monitoring and decision support system will be explained. Fault detection is an important part of the fault-tolerant design for in-service monitoring and decision support systems for ships. In the paper, a virtual example of fault detection will be p...

  6. Faults and Diagnosis Systems in Power Converters

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Choi, Uimin

    2014-01-01

    efforts have been put into making these systems better in terms of reliability in order to achieve high power source availability, reduce the cost of energy and also increase the reliability of overall systems. Among the components used in power converters, a power device and a capacitor fault occurs most...

  7. Study of fault diagnosis software design for complex system based on fault tree

    International Nuclear Information System (INIS)

    Complex systems always have high-level reliability and safety requirements, and same does their diagnosis work. As a great deal of fault tree models have been acquired during the design and operation phases, a fault diagnosis method which combines fault tree analysis with knowledge-based technology has been proposed. The prototype of fault diagnosis software has been realized and applied to mobile LIDAR system. (authors)

  8. Tectonics of the Levant fault system

    Science.gov (United States)

    Klinger, Yann

    2015-07-01

    In June 2013, for the second time, an international workshop dedicated to the tectonics of the Levant fault system and the Arabic plate was held in Paris. During two days, this meeting gathered researchers from 19 institutions and 12 countries, with 24 presentations. During this meeting, a large variety of topics were addressed, ranging from new insights into the geodynamics of the Red Sea to earthquake history along the Dead Sea fault. A key point of this meeting was actually to gather contributions focused on the same object, here the Levant fault system, but with different perspectives, to foster new collaborations and research projects. In line with this idea, several presentations were actually dealing with issues related to the palaeoclimate of this specific region, engineering issues about earthquake destructions, or the impact of the Dead Sea active tectonics on the evolution of hominins, aside from general tectonics.

  9. A master system for power system fault phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Myung Ho; Jang, Sang Ho; Hong, Joon Hee; Min, Wan Ki; Yoo, Chang Hwan [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center

    1995-12-31

    This report includes as follows - Real time digital simulator - Remote measuring, analyzing and reproducing system of power system fault data -Power system reduction method program using EMTP -Test system for protection device. (author). 22 refs., 38 figs.

  10. Guideliness for system modeling: fault tree [analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yoon Hwan; Yang, Joon Eon; Kang, Dae Il; Hwang, Mee Jeong

    2004-07-01

    This document, the guidelines for system modeling related to Fault Tree Analysis(FTA), is intended to provide the guidelines with the analyzer to construct the fault trees in the level of the capability category II of ASME PRA standard. Especially, they are to provide the essential and basic guidelines and the related contents to be used in support of revising the Ulchin 3 and 4 PSA model for risk monitor within the capability category II of ASME PRA standard. Normally the main objective of system analysis is to assess the reliability of system modeled by Event Tree Analysis (ETA). A variety of analytical techniques can be used for the system analysis, however, FTA method is used in this procedures guide. FTA is the method used for representing the failure logic of plant systems deductively using AND, OR or NOT gates. The fault tree should reflect all possible failure modes that may contribute to the system unavailability. This should include contributions due to the mechanical failures of the components, Common Cause Failures (CCFs), human errors and outages for testing and maintenance. This document identifies and describes the definitions and the general procedures of FTA and the essential and basic guidelines for reving the fault trees. Accordingly, the guidelines for FTA will be capable to guide the FTA to the level of the capability category II of ASME PRA standard.

  11. Observer-based Fault Detection and Isolation for Nonlinear Systems

    DEFF Research Database (Denmark)

    Lootsma, T.F.

    -tolerance can be applied to ordinary industrial processes that are not categorized as high risk applications, but where high availability is desirable. The quality of fault-tolerant control is totally dependent on the quality of the underlying algorithms. They detect possible faults, and later reconfigure......With the rise in automation the increase in fault detectionand isolation & reconfiguration is inevitable. Interest in fault detection and isolation (FDI) for nonlinear systems has grown significantly in recent years. The design of FDI is motivated by the need for knowledge about occurring faults in...... fault-tolerant control systems (FTC systems). The idea of FTC systems is to detect, isolate, and handle faults in such a way that the systems can still perform in a required manner. One prefers reduced performance after occurrence of a fault to the shut down of (sub-) systems. Hence, the idea of fault...

  12. Fault systems of the 1971 San Fernando and 1994 Northridge earthquakes, southern California: Relocated aftershocks and seismic images from LARSE II

    Science.gov (United States)

    Fuis, G.S.; Clayton, R.W.; Davis, P.M.; Ryberg, T.; Lutter, W.J.; Okaya, D.A.; Hauksson, E.; Prodehl, C.; Murphy, J.M.; Benthien, M.L.; Baher, S.A.; Kohler, M.D.; Thygesen, K.; Simila, G.; Keller, Gordon R.

    2003-01-01

    We have constructed a composite image of the fault systems of the M 6.7 San Fernando (1971) and Northridge (1994), California, earthquakes, using industry reflection and oil test well data in the upper few kilometers of the crust, relocated aftershocks in the seismogenic crust, and LARSE II (Los Angeles Region Seismic Experiment, Phase II) reflection data in the middle and lower crust. In this image, the San Fernando fault system appears to consist of a decollement that extends 50 km northward at a dip of ???25?? from near the surface at the Northridge Hills fault, in the northern San Fernando Valley, to the San Andreas fault in the middle to lower crust. It follows a prominent aseismic reflective zone below and northward of the main-shock hypocenter. Interpreted upward splays off this decollement include the Mission Hills and San Gabriel faults and the two main rupture planes of the San Fernando earthquake, which appear to divide the hanging wall into shingle- or wedge-like blocks. In contrast, the fault system for the Northridge earthquake appears simple, at least east of the LARSE II transect, consisting of a fault that extends 20 km southward at a dip of ???33?? from ???7 km depth beneath the Santa Susana Mountains, where it abuts the interpreted San Fernando decollement, to ???20 km depth beneath the Santa Monica Mountains. It follows a weak aseismic reflective zone below and southward of the mainshock hypocenter. The middle crustal reflective zone along the interpreted San Fernando decollement appears similar to a reflective zone imaged beneath the San Gabriel Mountains along the LARSE I transect, to the east, in that it appears to connect major reverse or thrust faults in the Los Angeles region to the San Andreas fault. However, it differs in having a moderate versus a gentle dip and in containing no mid-crustal bright reflections.

  13. Study on Knowledge -based Intelligent Fault Diagnosis of Hydraulic System

    Directory of Open Access Journals (Sweden)

    Xuexia Liu

    2012-12-01

    Full Text Available A general framework of hydraulic fault diagnosis system was studied. It consisted of equipment knowledge bases, real-time databases, fusion reasoning module, knowledge acquisition module and so on. A tree-structure model of fault knowledge was established. Fault nodes knowledge was encapsulated by object-oriented technique. Complete knowledge bases were made including fault bases and diagnosis bases. It could describe the fault positions, the structure of fault, cause-symptom relationships, diagnosis principles and other knowledge. Taking the fault of left and right lifting oil cylinder out of sync for example, the diagnostic results show that the methods were effective.

  14. Guaranteed Cost Fault-Tolerant Control for Networked Control Systems with Sensor Faults

    Directory of Open Access Journals (Sweden)

    Qixin Zhu

    2015-01-01

    Full Text Available For the large scale and complicated structure of networked control systems, time-varying sensor faults could inevitably occur when the system works in a poor environment. Guaranteed cost fault-tolerant controller for the new networked control systems with time-varying sensor faults is designed in this paper. Based on time delay of the network transmission environment, the networked control systems with sensor faults are modeled as a discrete-time system with uncertain parameters. And the model of networked control systems is related to the boundary values of the sensor faults. Moreover, using Lyapunov stability theory and linear matrix inequalities (LMI approach, the guaranteed cost fault-tolerant controller is verified to render such networked control systems asymptotically stable. Finally, simulations are included to demonstrate the theoretical results.

  15. Study on Software Fault Injection Based on Onboard System

    Institute of Scientific and Technical Information of China (English)

    PENGJunjie; HONGBingrong; YUANChengjun; LIAiguo; WEIZhenhua; QIAOYongqiang

    2005-01-01

    Fault injection techniques are the effective methods to evaluate the dependability and validate the fault tolerance mechanisms of computer systems. Among the different fault injection techniques, software implemented fault injection technique is regarded as one of the most promising technique for evaluation of the dependability of computer systems. In this paper, combined the advantages of software fault injection and the particularity of onboard system, a new software fault injection model, which can be used to evaluate the dependability and validate the fault tolerance mechanisms of the onboard system, is put forward. To evaluate the dependability of on boardsystem effectively, the application algorithm on how to use the model is presented. The experimental results show that using the fault injection model and algorithm put forward in this paper, not only most of low-level faults such as processor register faults, memory faults and so on can be injected, but also some high-level faults such as code faults, branch faults etc. can be injected, which can be used to evaluate the dependability of the onboard systems.

  16. Abstractions for Fault-Tolerant Distributed System Verification

    Science.gov (United States)

    Pike, Lee S.; Maddalon, Jeffrey M.; Miner, Paul S.; Geser, Alfons

    2004-01-01

    Four kinds of abstraction for the design and analysis of fault tolerant distributed systems are discussed. These abstractions concern system messages, faults, fault masking voting, and communication. The abstractions are formalized in higher order logic, and are intended to facilitate specifying and verifying such systems in higher order theorem provers.

  17. 3D Dynamic Rupture Simulation Across a Complex Fault System: the Mw7.0, 2010, Haiti Earthquake

    Science.gov (United States)

    Douilly, R.; Aochi, H.; Calais, E.; Freed, A. M.

    2013-12-01

    Earthquakes ruptures sometimes take place on a secondary fault and surprisingly do not activate an adjacent major one. The 1989 Loma Prieta earthquake is a classic case where rupture occurred on a blind thrust while the adjacent San Andreas Fault was not triggered during the process. Similar to Loma Prieta, the Mw7.0, January 12 2010, Haiti earthquake also ruptured a secondary blind thrust, the Léogâne fault, adjacent to the main plate boundary, the Enriquillo Plantain Garden Fault, which did not rupture during this event. Aftershock relocalizations delineate the Léogâne rupture with two north dipping segments with slightly different dip, where the easternmost segment had mostly dip-slip motion and the westernmost one had mostly strike-slip motion. In addition, an offshore south dipping structure inferred from the aftershocks to the west of the rupture zone coincides with the offshore Trois Baies reverse fault, a region of increase in Coulomb stress increase. In this study, we investigate the rupture dynamics of the Haiti earthquake in a complex fault system of multiple segments identified by the aftershock relocations. We suppose a background stress regime that is consistent with the type of motion of each fault and with the regional tectonic regime. We initiate a nucleation on the east segment of the Léogâne fault by defining a circular region with a 2 km radius where shear stress is slightly greater than the yield stress. By varying friction on faults and background stress, we find a range of plausible scenarios. In the absence of near-field seismic records of the event, we score the different models against the static deformation field derived from GPS and InSAR at the surface. All the plausible simulations show that the rupture propagates from the eastern to the western segment along the Léogâne fault, but not on the Enriquillo fault nor on the Trois Baies fault. The best-fit simulation shows a significant increase of shear stresses on the Trois Baies

  18. Robust Fault Detection and Isolation for Stochastic Systems

    Science.gov (United States)

    George, Jemin; Gregory, Irene M.

    2010-01-01

    This paper outlines the formulation of a robust fault detection and isolation scheme that can precisely detect and isolate simultaneous actuator and sensor faults for uncertain linear stochastic systems. The given robust fault detection scheme based on the discontinuous robust observer approach would be able to distinguish between model uncertainties and actuator failures and therefore eliminate the problem of false alarms. Since the proposed approach involves precise reconstruction of sensor faults, it can also be used for sensor fault identification and the reconstruction of true outputs from faulty sensor outputs. Simulation results presented here validate the effectiveness of the robust fault detection and isolation system.

  19. Coulomb stress interactions among M≥5.9 earthquakes in the Gorda deformation zone and on the Mendocino Fracture Zone, Cascadia megathrust, and northern San Andreas fault

    Science.gov (United States)

    Rollins, John C.; Stein, Ross S.

    2010-01-01

    The Gorda deformation zone, a 50,000 km2 area of diffuse shear and rotation offshore northernmost California, has been the site of 20 M ≥ 5.9 earthquakes on four different fault orientations since 1976, including four M ≥ 7 shocks. This is the highest rate of large earthquakes in the contiguous United States. We calculate that the source faults of six recent M ≥ 5.9 earthquakes had experienced ≥0.6 bar Coulomb stress increases imparted by earthquakes that struck less than 9 months beforehand. Control tests indicate that ≥0.6 bar Coulomb stress interactions between M ≥ 5.9 earthquakes separated by Mw = 7.3 Trinidad earthquake are consistent with the locations of M ≥ 5.9 earthquakes in the Gorda zone until at least 1995, as well as earthquakes on the Mendocino Fault Zone in 1994 and 2000. Coulomb stress changes imparted by the 1980 earthquake are also consistent with its distinct elbow-shaped aftershock pattern. From these observations, we derive generalized static stress interactions among right-lateral, left-lateral and thrust faults near triple junctions.

  20. Physiochemical Evidence of Faulting Processes and Modeling of Fluid in Evolving Fault Systems in Southern California

    Energy Technology Data Exchange (ETDEWEB)

    Boles, James [Professor

    2013-05-24

    Our study targets recent (Plio-Pleistocene) faults and young (Tertiary) petroleum fields in southern California. Faults include the Refugio Fault in the Transverse Ranges, the Ellwood Fault in the Santa Barbara Channel, and most recently the Newport- Inglewood in the Los Angeles Basin. Subsurface core and tubing scale samples, outcrop samples, well logs, reservoir properties, pore pressures, fluid compositions, and published structural-seismic sections have been used to characterize the tectonic/diagenetic history of the faults. As part of the effort to understand the diagenetic processes within these fault zones, we have studied analogous processes of rapid carbonate precipitation (scaling) in petroleum reservoir tubing and manmade tunnels. From this, we have identified geochemical signatures in carbonate that characterize rapid CO2 degassing. These data provide constraints for finite element models that predict fluid pressures, multiphase flow patterns, rates and patterns of deformation, subsurface temperatures and heat flow, and geochemistry associated with large fault systems.

  1. Estimation of Faults in DC Electrical Power System

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper demonstrates a novel optimizationbased approach to estimating fault states in a DC power system. The model includes faults changing the circuit topology...

  2. Fault Adaptive Control of Overactuated Systems Using Prognostic Estimation

    Data.gov (United States)

    National Aeronautics and Space Administration — Most fault adaptive control research addresses the preservation of system stability or functionality in the presence of a specific failure (fault). This paper...

  3. Advanced Ground Systems Maintenance Functional Fault Models For Fault Isolation Project

    Science.gov (United States)

    Perotti, Jose M. (Compiler)

    2014-01-01

    This project implements functional fault models (FFM) to automate the isolation of failures during ground systems operations. FFMs will also be used to recommend sensor placement to improve fault isolation capabilities. The project enables the delivery of system health advisories to ground system operators.

  4. Study of fault injection system based on software

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A software fault injection system SFIS is designed, which consists of the target system plus a fault injector, fault library, workload, data collector, and data analyzer. A serial communication mechanism is adopted to simulate the factual work environment. Then a fault model is built for single particle event, which can be denoted as FM = (FL, FT). FL stands for fault location, and FT stands for fault type. The fault model supports three temporal faults: transient, intermittent, and permanent. During the experiments implemented by SFIS,the software interruption method is adopted to inject transient faults, and step trace method is adopted to inject permanent faults into the target system. The experiment results indicate that for the injected transient code segment faults, 2.8% of them do not affect the program output, 80.1% of them are detected by the built-in error detection in the system, and 17.1% of them are not detected by fault detection mechanism. The experiment results verify the validity of the fault injection method.

  5. Data-driven design of fault diagnosis and fault-tolerant control systems

    CERN Document Server

    Ding, Steven X

    2014-01-01

    Data-driven Design of Fault Diagnosis and Fault-tolerant Control Systems presents basic statistical process monitoring, fault diagnosis, and control methods, and introduces advanced data-driven schemes for the design of fault diagnosis and fault-tolerant control systems catering to the needs of dynamic industrial processes. With ever increasing demands for reliability, availability and safety in technical processes and assets, process monitoring and fault-tolerance have become important issues surrounding the design of automatic control systems. This text shows the reader how, thanks to the rapid development of information technology, key techniques of data-driven and statistical process monitoring and control can now become widely used in industrial practice to address these issues. To allow for self-contained study and facilitate implementation in real applications, important mathematical and control theoretical knowledge and tools are included in this book. Major schemes are presented in algorithm form and...

  6. Robust fault diagnosis for a class of nonlinear systems

    Institute of Scientific and Technical Information of China (English)

    Zhanshan WANG; Huaguang ZHANG

    2006-01-01

    Robust fault diagnosis based on adaptive observer is studied for a class of nonlinear systems up to output injection. Adaptive fault updating laws are designed to guarantee the stability of the diagnosis system. The upper bounds of the state estimation error and fault estimation error of the adaptive observer are given respectively and the effects of parameter in the adaptive updating laws on fault estimation accuracy are also discussed. Simulation example demonstrates the effectiveness of the proposed methods and the analysis results.

  7. Fault tolerant architecture for artificial olfactory system

    International Nuclear Information System (INIS)

    In this paper, to cover and mask the faults that occur in the sensing unit of an artificial olfactory system, a novel architecture is offered. The proposed architecture is able to tolerate failures in the sensors of the array and the faults that occur are masked. The proposed architecture for extracting the correct results from the output of the sensors can provide the quality of service for generated data from the sensor array. The results of various evaluations and analysis proved that the proposed architecture has acceptable performance in comparison with the classic form of the sensor array in gas identification. According to the results, achieving a high odor discrimination based on the suggested architecture is possible. (paper)

  8. Fault diagnostic system for a mobile robot

    Science.gov (United States)

    Nikam, Umesh; Hall, Ernest L.

    1997-09-01

    This paper describes the development of a robot fault diagnosis system (RFDS). Though designed ostensibly for the University of Cincinnati's autonomous, unmanned, mobile robot for a national competition, it has the flexibility to be adapted for industrial applications as well. Using a top-down approach the robot is sub-divided into different functional units, such as the vision guidance system, the ultrasonic obstacle avoidance system, the steering mechanism, the speed control system, the braking system and the power unit. The techniques of potential failure mode and effects analysis (PFMEA) are used to analyze faults, their visible symptoms, and probable causes and remedies. The relationships obtained therefrom are mapped in a database framework. This is then coded in a user-friendly interactive Visual BasicTM program that guides the user to the likely cause(s) of failure through a question-answer format. A provision is made to ensure better accuracy of the system by incorporating historical data on failures as it becomes available. The RFDS thus provides a handy trouble-shooting tool that cuts down the time involved in diagnosing failures in the complex robot consisting of mechanical, electric, electronic and optical systems. This has been of great help in diagnosing failures and ensuring maximum performance from the robot during the contest in the face of pressure of the competition and the outdoor conditions.

  9. Accurate fault location technique for distribution system using fault-generated high-frequency transient voltage signals

    Energy Technology Data Exchange (ETDEWEB)

    Bo, Z.Q.; Weller, G. [Alstom T and D Protection Control Ltd., Stafford (United Kingdom); Redfern, M.A. [University of Bath (United Kingdom). Dept. of Electronic and Electrical Engineering

    1999-01-01

    A technique is presented for accurate fault location on distribution overhead lines and underground cables. A specially designed fault locator unit is used to capture the high-frequency voltage transient signal generated by faults on the distribution line/cable. The travelling time of the high-frequency components is used to determine the fault position. The technique is insensitive to fault type, fault resistance, fault inception angle and system source configuration, and is able to offer very high accuracy in fault location in a distribution system. (author)

  10. Faults

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Through the study of faults and their effects, much can be learned about the size and recurrence intervals of earthquakes. Faults also teach us about crustal...

  11. Discrete Wavelet Transform for Fault Locations in Underground Distribution System

    Science.gov (United States)

    Apisit, C.; Ngaopitakkul, A.

    2010-10-01

    In this paper, a technique for detecting faults in underground distribution system is presented. Discrete Wavelet Transform (DWT) based on traveling wave is employed in order to detect the high frequency components and to identify fault locations in the underground distribution system. The first peak time obtained from the faulty bus is employed for calculating the distance of fault from sending end. The validity of the proposed technique is tested with various fault inception angles, fault locations and faulty phases. The result is found that the proposed technique provides satisfactory result and will be very useful in the development of power systems protection scheme.

  12. Paleoseismology and Fault Interactions of the Pajarito Fault System, Rio Grande Rift, New Mexico

    Science.gov (United States)

    Gardner, J. N.; Lewis, C. J.; Lavine, A.; Reneau, S. L.; Schultz, E. S.

    2006-12-01

    The Pajarito fault system is the local active boundary fault of the Rio Grande rift in the vicinity of Los Alamos, New Mexico. Detailed geologic and geomorphic mapping, and displacement-length profiles, reveal a complex pattern of structural deformation that suggests interaction and connective growth among the principal faults in the system (Pajarito, Rendija Canyon, Guaje Mountain, and Santa Clara faults, totaling ~55 km in length). At the surface, the Pajarito fault is not a single shear surface but a complex zone of deformation with considerable lateral variation in structural style from south to north. In the area of detailed mapping, the Pajarito fault is a broad zone of distributed deformation: at the southwest corner of the area, structure is dominated by a large monocline, but small faults and monoclines span a breadth of about 2 km with about 125 m of displacement in the last 1.2 million years; at the west central part of the area, the Pajarito fault is expressed as mainly a large normal fault with smaller faults spread across about 1 km with about 80 m of displacement in the last 1.2 million years; and, in the northwestern part of the area, structure is again dominated by a large monocline with normal faulting in a zone about 1.5 km wide with about 65 m of displacement in the last 1.2 million years. These along-strike variations in the deformation of the Pajarito fault suggest that in most places the tip of the master fault does not break the surface; instead, most of what can be observed is subsidiary structure. The implication of the complex structure and styles of deformation in the fault is that it severely complicates paleoseismic exploration for hazard analyses because different subsidiary structures rupture in different seismic events; no individual structure can be identified with even a near- complete paleoseismic record. Additionally, surface rupture hazards must be associated with broad zones instead of individual faults. Seven paleoseismic

  13. Advanced information processing system: Fault injection study and results

    Science.gov (United States)

    Burkhardt, Laura F.; Masotto, Thomas K.; Lala, Jaynarayan H.

    1992-01-01

    The objective of the AIPS program is to achieve a validated fault tolerant distributed computer system. The goals of the AIPS fault injection study were: (1) to present the fault injection study components addressing the AIPS validation objective; (2) to obtain feedback for fault removal from the design implementation; (3) to obtain statistical data regarding fault detection, isolation, and reconfiguration responses; and (4) to obtain data regarding the effects of faults on system performance. The parameters are described that must be varied to create a comprehensive set of fault injection tests, the subset of test cases selected, the test case measurements, and the test case execution. Both pin level hardware faults using a hardware fault injector and software injected memory mutations were used to test the system. An overview is provided of the hardware fault injector and the associated software used to carry out the experiments. Detailed specifications are given of fault and test results for the I/O Network and the AIPS Fault Tolerant Processor, respectively. The results are summarized and conclusions are given.

  14. Study on fault diagnose expert system for large astronomy telescope

    Science.gov (United States)

    Liu, Jia-jing; Luo, Ming-Cheng; Tang, Peng-yi; Wu, Wen-qing; Zhang, Guang-yu; Zhang, Hong-fei; Wang, Jian

    2014-08-01

    The development of astronomical techniques and telescopes currently entered a new vigorous period. The telescopes have trends of the giant, complex, diversity of equipment and wide span of control despite of optical, radio space telescopes. That means, for telescope observatory, the control system must have these specifications: flexibility, scalability, distributive, cross-platform and real-time, especially the fault locating and fault processing is more important when fault or exception arise. Through the analysis of the structure of large telescopes, fault diagnosis expert system of large telescope based on the fault tree and distributed log service is given.

  15. Estimation of Parametric Fault in Closed-loop Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2015-01-01

    The aim of this paper is to present a method for estimation of parametric faults in closed-loop systems. The key technology applied in this paper is coprime factorization of both the dynamic system as well as the feedback controller. Using the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization, it...... is shown that a certain matrix transfer function, the fault signature matrix, is an LFT (linear fractional transformation) of the parametric faults. Further, for limit parametric faults, the fault signature matrix transfer function can be approximated with a linear matrix function of the parametric...

  16. Fault-tolerant Actuator System for Electrical Steering of Vehicles

    DEFF Research Database (Denmark)

    Sørensen, Jesper Sandberg; Blanke, Mogens

    2006-01-01

    Being critical to the safety of vehicles, the steering system is required to maintain the vehicles ability to steer until it is brought to halt, should a fault occur. With electrical steering becoming a cost-effective candidate for electrical powered vehicles, a fault-tolerant architecture is...... needed that meets this requirement. This paper studies the fault-tolerance properties of an electrical steering system. It presents a fault-tolerant architecture where a dedicated AC motor design used in conjunction with cheap voltage measurements can ensure detection of all relevant faults in the...

  17. Novel Fault Diagnosis Scheme for HVDC System via ESO

    Institute of Scientific and Technical Information of China (English)

    YAN Bing-yong; TIAN Zuo-hua; SHI Song-jiao

    2007-01-01

    A novel fault detection and identification (FDI) scheme for HVDC (High Voltage Direct Current Transmission) system was presented. It was based on the unique active disturbance rejection concept, where the HVDC system faults were estimated using an extended states observer (ESO). Firstly, the mathematical model of HVDC system was constructed, where the system states and disturbance were treated as an extended state. An augment HVDC system was established by using the extended state in rectify side and converter side, respectively. Then, a fault diagnosis filter was established to diagnose the HVDC system faults via the ESO theory. The evolution of the extended state in the augment HVDC system can reflect the actual system faults and disturbances, which can be used for the fault diagnosis purpose. A novel feature of this approach is that it can simultaneously detect and identify the shape and magnitude of the HVDC faults and disturbance. Finally, different kinds of HVDC faults were simulated to illustrate the feasibility and effectiveness of the proposed ESO based FDI approach. Compared with the neural network based or support vector machine based FDI approach, the ESO based FDI scheme can reduce the fault detection time dramatically and track the actual system fault accurately. What's more important, it needs not do complex online calculations and the training of neural network so that it can be applied into practice.

  18. Method and system for environmentally adaptive fault tolerant computing

    Science.gov (United States)

    Copenhaver, Jason L. (Inventor); Jeremy, Ramos (Inventor); Wolfe, Jeffrey M. (Inventor); Brenner, Dean (Inventor)

    2010-01-01

    A method and system for adapting fault tolerant computing. The method includes the steps of measuring an environmental condition representative of an environment. An on-board processing system's sensitivity to the measured environmental condition is measured. It is determined whether to reconfigure a fault tolerance of the on-board processing system based in part on the measured environmental condition. The fault tolerance of the on-board processing system may be reconfigured based in part on the measured environmental condition.

  19. Bond graph model-based fault diagnosis of hybrid systems

    CERN Document Server

    Borutzky, Wolfgang

    2015-01-01

    This book presents a bond graph model-based approach to fault diagnosis in mechatronic systems appropriately represented by a hybrid model. The book begins by giving a survey of the fundamentals of fault diagnosis and failure prognosis, then recalls state-of-art developments referring to latest publications, and goes on to discuss various bond graph representations of hybrid system models, equations formulation for switched systems, and simulation of their dynamic behavior. The structured text: • focuses on bond graph model-based fault detection and isolation in hybrid systems; • addresses isolation of multiple parametric faults in hybrid systems; • considers system mode identification; • provides a number of elaborated case studies that consider fault scenarios for switched power electronic systems commonly used in a variety of applications; and • indicates that bond graph modelling can also be used for failure prognosis. In order to facilitate the understanding of fault diagnosis and the presented...

  20. Intelligent System for Fault Diagnosis in Automotive Applications

    OpenAIRE

    Kabir, Mashud

    2008-01-01

    This work presents an intelligent system for fault diagnosis in automotive applications. The system is proposed to handle faults in a running car as well as in a car which is in the process of being developed. The main goal of this work is to use the vast knowledge previously acquired by system experts, to visualize, localize and fix a fault in any of the life phases of a car. The existing techniques and systems which are in use for fault diagnosis are investigated. There is no system which c...

  1. Fault tolerant aggregation for power system services

    DEFF Research Database (Denmark)

    Kosek, Anna Magdalena; Gehrke, Oliver; Kullmann, Daniel

    2013-01-01

    Exploiting the flexibility in distributed energy resources (DER) is seen as an important contribution to allow high penetrations of renewable generation in electrical power systems. However, the present control infrastructure in power systems is not well suited for the integration of a very large...... number of small units. A common approach is to aggregate a portfolio of such units together and expose them to the power system as a single large virtual unit. In order to realize the vision of a Smart Grid, concepts for flexible, resilient and reliable aggregation infrastructures are required. This...... paper presents such a concept while focusing on the aspect of resilience and fault tolerance. The proposed concept makes use of a multi-level election algorithm to transparently manage the addition, removal, failure and reorganization of units. It has been implemented and tested as a proof-of-concept on...

  2. Teatrikunstnik Andrea Haamer: Olen alati unistanud Eestisse tagasi tulla / Andrea Haamer ; intervjueerinud Andreas Sepp, Anneli Sihvart

    Index Scriptorium Estoniae

    Haamer, Andrea

    2011-01-01

    Eesti juurtega lava- ja kostüümikunstnikust Andrea T. Haamerist, kes on Eestis kujundanud kolm balletti. 25. veebruaril avatavast neljandast Jõhvi balletifestivalist, kus avatakse Andrea Haameri näitus

  3. Fault evolution-test dependency modeling for mechanical systems

    Institute of Scientific and Technical Information of China (English)

    Xiao-dong TAN; Jian-lu LUO; Qing LI; Bing LU; Jing QIU

    2015-01-01

    Tracking the process of fault growth in mechanical systems using a range of tests is important to avoid catastrophic failures. So, it is necessary to study the design for testability (DFT). In this paper, to improve the testability performance of me-chanical systems for tracking fault growth, a fault evolution-test dependency model (FETDM) is proposed to implement DFT. A testability analysis method that considers fault trackability and predictability is developed to quantify the testability performance of mechanical systems. Results from experiments on a centrifugal pump show that the proposed FETDM and testability analysis method can provide guidance to engineers to improve the testability level of mechanical systems.

  4. Observer-Based Fault Estimation and Accomodation for Dynamic Systems

    CERN Document Server

    Zhang, Ke; Shi, Peng

    2013-01-01

    Due to the increasing security and reliability demand of actual industrial process control systems, the study on fault diagnosis and fault tolerant control of dynamic systems has received considerable attention. Fault accommodation (FA) is one of effective methods that can be used to enhance system stability and reliability, so it has been widely and in-depth investigated and become a hot topic in recent years. Fault detection is used to monitor whether a fault occurs, which is the first step in FA. On the basis of fault detection, fault estimation (FE) is utilized to determine online the magnitude of the fault, which is a very important step because the additional controller is designed using the fault estimate. Compared with fault detection, the design difficulties of FE would increase a lot, so research on FE and accommodation is very challenging. Although there have been advancements reported on FE and accommodation for dynamic systems, the common methods at the present stage have design difficulties, whi...

  5. Algorithmic fault tree construction by component-based system modeling

    International Nuclear Information System (INIS)

    Computer-aided fault tree generation can be easier, faster and less vulnerable to errors than the conventional manual fault tree construction. In this paper, a new approach for algorithmic fault tree generation is presented. The method mainly consists of a component-based system modeling procedure an a trace-back algorithm for fault tree synthesis. Components, as the building blocks of systems, are modeled using function tables and state transition tables. The proposed method can be used for a wide range of systems with various kinds of components, if an inclusive component database is developed. (author)

  6. A BRB Based Fault Prediction Method of Complex Electromechanical Systems

    Directory of Open Access Journals (Sweden)

    Bangcheng Zhang

    2015-01-01

    Full Text Available Fault prediction is an effective and important approach to improve the reliability and reduce the risk of accidents for complex electromechanical systems. In order to use the quantitative information and qualitative knowledge efficiently to predict the fault, a new model is proposed on the basis of belief rule base (BRB. Moreover, an evidential reasoning (ER based optimal algorithm is developed to train the fault prediction model. The screw failure in computer numerical control (CNC milling machine servo system is taken as an example and the fault prediction results show that the proposed method can predict the behavior of the system accurately with combining qualitative knowledge and some quantitative information.

  7. Kinematically Coupled Strike-Slip and Normal Faults in the Lake Mead Strike-Slip Fault System, Southeast Nevada

    Science.gov (United States)

    Kattenhorn, S. A.; Marshall, S. T.; Cooke, M. L.

    2008-12-01

    The Lake Mead fault system consists of a ~95 km long, northeast-trending zone of strike-slip faults of Miocene age that accommodate a total left-lateral offset of 20-65 km. We use a combination of detailed field mapping and numerical modeling to show that a previously unnamed left-lateral strike-slip segment of the Lake Mead fault system and a dense cluster of dominantly west-dipping normal faults acted in concert to accommodate regional left-lateral offset. We suggest that the strike-slip fault that we refer to as the Pinto Ridge fault: (1) was kinematically related to other faults of the Lake Mead fault system; (2) was responsible for the creation of the normal fault cluster at Pinto Ridge; and (3) utilized these normal faults as linking structures between separate strike-slip fault segments to create a longer, through-going fault. Results from numerical models demonstrate that the observed location and curving strike patterns of the normal fault cluster is consistent with the faults having formed as secondary structures as the result of the perturbed stress field around the slipping Pinto Ridge fault. Comparison of mechanical efficiency of various normal fault geometries within extending terranes suggests that the observed west dip of normal faults reflects a west- dipping anisotropy at depth, such as a detachment. The apparent terminations of numerous strike-slip faults of the Lake Mead fault system into west-dipping normal faults suggest that a west-dipping detachment may be regionally coherent.

  8. FaultBuster: data driven fault detection and diagnosis for industrial systems

    OpenAIRE

    Bergantino, Nicola; Caponetti, Fabio; Longhi, Sauro

    2009-01-01

    Efficient and reliable monitoring systems are mandatory to assure the required security standards in industrial complexes. This paper describes the recent developments of FaultBuster, a purely data-driven diagnostic system. It is designed so to be easily scalable to different monitor tasks. Multivariate statistical models based on principal components are used to detect abnormal situations. Tailored to alarms, a probabilistic inference engine process the fault evidences to output the most pro...

  9. Morphostructural study of the Belledonne faults system (French Alps).

    Science.gov (United States)

    Billant, Jérémy; Bellier, Olivier; Hippolyte, Jean-Claude; Godard, Vincent; Manchuel, Kevin

    2016-04-01

    The NE trending Belledonne faults system, located in the Alps, is a potentially active faults system that extends from the Aiguilles Rouges and Mont Blanc massifs in the NE to the Vercors massif in the SW (subalpine massifs). It includes the Belledonne border fault (BBF), defined by an alignment of micro earthquakes (ML≤3.5) along the eastern part of the Grésivaudan valley (Thouvenot et al., 2003). Focal mechanisms and their respective depths tend to confirm a dextral strike-slip faulting at crustal scale. In the scope of the Sigma project (http://projet-sigma.com/index.html, EDF), this study aims at better constraining the geometry, kinematic and seismogenic potential of the constitutive faults of the Belledonne fault system, by using a multidisciplinary approach that includes tectonics, geomorphology and geophysics. Fault kinematic analysis along the BBF (Billant et al., 2015) and the Jasneuf fault allows the determination of a strike-slip tectonic regime characterised by an ENE trending σ1 stress axes, which is consistent with stress state deduced from the focal mechanisms. Although no morphological anomalies could be related to recent faulting along the BBF, new clues of potential Quaternary deformations were observed along the other faults of the system: -right lateral offset of morphologic markers (talwegs...) along the NE trending Arcalod fault located at the north-eastern terminations of the BBF; -left lateral offset of the valley formed by the Isère glacier along the NW trending Brion fault which is consistent with its left-lateral slip inferred from the focal mechanisms; -fault scarps and right lateral offsets of cliffs bordering a calcareous plateau and talwegs along the four fault segments of the NE trending Jasneuf fault located at the south-western termination of the BBF in the Vercors massif. Some offsets were measured using a new method that does not require the identification of piercing points and take advantage of the high resolution

  10. Model-based fault diagnosis in PEM fuel cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Escobet, T.; de Lira, S.; Puig, V.; Quevedo, J. [Automatic Control Department (ESAII), Universitat Politecnica de Catalunya (UPC), Rambla Sant Nebridi 10, 08222 Terrassa (Spain); Feroldi, D.; Riera, J.; Serra, M. [Institut de Robotica i Informatica Industrial (IRI), Consejo Superior de Investigaciones Cientificas (CSIC), Universitat Politecnica de Catalunya (UPC) Parc Tecnologic de Barcelona, Edifici U, Carrer Llorens i Artigas, 4-6, Planta 2, 08028 Barcelona (Spain)

    2009-07-01

    In this work, a model-based fault diagnosis methodology for PEM fuel cell systems is presented. The methodology is based on computing residuals, indicators that are obtained comparing measured inputs and outputs with analytical relationships, which are obtained by system modelling. The innovation of this methodology is based on the characterization of the relative residual fault sensitivity. To illustrate the results, a non-linear fuel cell simulator proposed in the literature is used, with modifications, to include a set of fault scenarios proposed in this work. Finally, it is presented the diagnosis results corresponding to these fault scenarios. It is remarkable that with this methodology it is possible to diagnose and isolate all the faults in the proposed set in contrast with other well known methodologies which use the binary signature matrix of analytical residuals and faults. (author)

  11. Application of fault tree analysis to sucker rod pumping systems

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Z. [Texas Tech Univ., Lubbock, TX (United States). Center for Energy Research

    1997-08-01

    The Fault Tree Analysis technique was applied to the reliability analysis of the sucker-rod pumping system. Although the most widely used form of artificial lift, it is known to be vulnerable to failure. This study describes salient features of the Fault Tree System, and provides detailed application procedures to demonstrate the feasibility of this technique.

  12. Fault diagnosis of nuclear equipment based on artificial immune system

    International Nuclear Information System (INIS)

    As the nuclear equipment is complicate and special, this paper put forward a novel fault diagnosis method for nuclear equipment based on artificial immune system and the principle to model with negative-selection algorithm and further identify the fault with clone-variation algorithm. Features are extracted with the signal that was sampled in a rotary machinery, then the result is input to the AIS model. Simulation result shows that the model can identify each fault type successfully. (authors)

  13. Fault Tolerance in Distributed Systems using Fused State Machines

    OpenAIRE

    Balasubramanian, Bharath; Garg, Vijay K

    2013-01-01

    Replication is a standard technique for fault tolerance in distributed systems modeled as deterministic finite state machines (DFSMs or machines). To correct f crash or f/2 Byzantine faults among n different machines, replication requires nf additional backup machines. We present a solution called fusion that requires just f additional backup machines. First, we build a framework for fault tolerance in DFSMs based on the notion of Hamming distances. We introduce the concept of an (f,m)-fusion...

  14. Non deterministic finite automata for power systems fault diagnostics

    Directory of Open Access Journals (Sweden)

    LINDEN, R.

    2009-06-01

    Full Text Available This paper introduces an application based on finite non-deterministic automata for power systems diagnosis. Automata for the simpler faults are presented and the proposed system is compared with an established expert system.

  15. Fault Diagnosis of Nonlinear Systems Using Structured Augmented State Models

    Institute of Scientific and Technical Information of China (English)

    Jochen Aβfalg; Frank Allg(o)wer

    2007-01-01

    This paper presents an internal model approach for modeling and diagnostic functionality design for nonlinear systems operating subject to single- and multiple-faults. We therefore provide the framework of structured augmented state models. Fault characteristics are considered to be generated by dynamical exosystems that are switched via equality constraints to overcome the augmented state observability limiting the number of diagnosable faults. Based on the proposed model, the fault diagnosis problem is specified as an optimal hybrid augmented state estimation problem. Sub-optimal solutions are motivated and exemplified for the fault diagnosis of the well-known three-tank benchmark. As the considered class of fault diagnosis problems is large, the suggested approach is not only of theoretical interest but also of high practical relevance.

  16. Fault Diagnosis for Electrical Distribution Systems using Structural Analysis

    DEFF Research Database (Denmark)

    Knüppel, Thyge; Blanke, Mogens; Østergaard, Jacob

    Fault-tolerance in electrical distribution relies on the ability to diagnose possible faults and determine which components or units cause a problem or are close to doing so. Faults include defects in instrumentation, power generation, transformation and transmission. The focus of this paper is the...... structure graph. This paper shows how three-phase networks are modelled and analysed using structural methods, and it extends earlier results by showing how physical faults can be identified such that adequate remedial actions can be taken. The paper illustrates a feasible modelling technique for structural...... analysis of power systems, it demonstrates detection and isolation of failures in a network, and shows how typical faults are diagnosed. Nonlinear fault simulations illustrate the results....

  17. Sensor Fault Tolerant Generic Model Control for Nonlinear Systems

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A modified Strong Tracking Filter (STF) is used to develop a new approach to sensor fault tolerant control. Generic Model Control (GMC) is used to control the nonlinear process while the process runs normally because of its robust control performance. If a fault occurs in the sensor, a sensor bias vector is then introduced to the output equation of the process model. The sensor bias vector is estimated on-line during every control period using the STF. The estimated sensor bias vector is used to develop a fault detection mechanism to supervise the sensors. When a sensor fault occurs, the conventional GMC is switched to a fault tolerant control scheme, which is, in essence, a state estimation and output prediction based GMC. The laboratory experimental results on a three-tank system demonstrate the effectiveness of the proposed Sensor Fault Tolerant Generic Model Control (SFTGMC) approach.

  18. Fault Reconstruction Approach for Distributed Coordinated Spacecraft Attitude Control System

    Directory of Open Access Journals (Sweden)

    Mingyi Huo

    2015-01-01

    Full Text Available This work presents a novel fault reconstruction approach for a large-scale system, that is, a distributed coordinated spacecraft attitude control system. The attitude of all the spacecrafts in this distributed system is controlled by using thrusters. All possible faults of thruster including thrust magnitude error and alignment error are investigated. As a stepping stone, the mathematical model of thruster is firstly established based on the thruster configuration. On the basis of this, a sliding mode observer is then proposed to reconstruct faults in each agent of the coordinated control system. A Lyapunov-based analysis shows that the observer asymptotically converges to the actual faults. The key feature of this fault reconstruction approach is that it can achieve a faster reconstruction of the fault in comparison with the conventional fault reconstruction schemes. It can globally reconstruct thruster faults with zero reconstruction error, and this is accomplished within finite time. The effectiveness of the proposed approach is analytically authenticated via simulation study.

  19. System assessment using modular logic fault tree methodology

    International Nuclear Information System (INIS)

    In the process of a Probabilistic Safety analysis (PSA) study a large number of fault trees are generated by different specialist. Modular Logic Fault Tree Methodology pave the way the way to systematize the procedures and to unify the criteria in the process of systems modulation. An example of of the application of this methodology is shown

  20. Adaptive Observer-Based Fault Estimate for Nonlinear Systems

    Institute of Scientific and Technical Information of China (English)

    ZONG Qun; LIU Wenjing; LIU Li

    2006-01-01

    An approach for adaptive observer-based fault estimate for nonlinear system is proposed.H-infinity theory is applied to analyzing the design method and stable conditions of the adaptive observer,from which both system state and fault can be estimated.It is proved that the fault estimate error is related to the given H-infinity track performance indexes,as well as to the changing rate of the fault and the Lipschitz constant of the nonlinear item.The design steps of the adaptive observer are proposed.The simulation results show that the observer has good performance for fault estimate even when the system includes nonlinear terms,which confirms the effectiveness of the method.

  1. Comparing fault susceptibility of multiple ISAs and operating systems

    Science.gov (United States)

    Chyłek, Sławomir

    2015-09-01

    This paper presents a research that aims to compare effects of faults on different configurations of computer systems. The study covers comparison of susceptibility to faults of x86, AMD64, ARM, PowerPC, MIPS architectures and Linux, FreeBSD, Minix operating systems. An emulation based software implemented fault injection technique was used to perform experiments. The problem of choosing an adequate number of tests in experiments is followed by report with collected results where multiple aspects of test runs were analyzed: providing correct computation result, availability of the system under test and error messages. The research allows to determine characteristics of susceptibility to faults of each platform and is a first step towards designing new fault tolerance solutions and assessing their effectiveness.

  2. Navigation System Fault Diagnosis for Underwater Vehicle

    DEFF Research Database (Denmark)

    Falkenberg, Thomas; Gregersen, Rene Tavs; Blanke, Mogens

    This paper demonstrates fault diagnosis on unmanned underwater vehicles (UUV) based on analysis of structure of the nonlinear dynamics. Residuals are generated using dierent approaches in structural analysis followed by statistical change detection. Hypothesis testing thresholds are made signal...

  3. High-Intensity Radiated Field Fault-Injection Experiment for a Fault-Tolerant Distributed Communication System

    Science.gov (United States)

    Yates, Amy M.; Torres-Pomales, Wilfredo; Malekpour, Mahyar R.; Gonzalez, Oscar R.; Gray, W. Steven

    2010-01-01

    Safety-critical distributed flight control systems require robustness in the presence of faults. In general, these systems consist of a number of input/output (I/O) and computation nodes interacting through a fault-tolerant data communication system. The communication system transfers sensor data and control commands and can handle most faults under typical operating conditions. However, the performance of the closed-loop system can be adversely affected as a result of operating in harsh environments. In particular, High-Intensity Radiated Field (HIRF) environments have the potential to cause random fault manifestations in individual avionic components and to generate simultaneous system-wide communication faults that overwhelm existing fault management mechanisms. This paper presents the design of an experiment conducted at the NASA Langley Research Center's HIRF Laboratory to statistically characterize the faults that a HIRF environment can trigger on a single node of a distributed flight control system.

  4. Oblique fault systems crossing the Seattle Basin: Geophysical evidence for additional shallow fault systems in the central Puget Lowland

    Science.gov (United States)

    Mace, Chris G.; Keranen, Katie M.

    2012-03-01

    Upper plate seismicity in the Puget Lowland is more broadly distributed than mapped fault systems and presents a conundrum for understanding the active tectonics of the region. Although many previous studies have mapped faulting in the Puget Lowland from subsurface geophysical data, many of these efforts have focused specifically on mapping the structure of the Seattle Fault Zone and the South Whidbey Island Fault. The thick glacial sediments and extensive water bodies may conceal additional active faults away from these major structures. We map fault networks in Quaternary sediments broadly throughout the central Puget Lowland using existing marine multichannel seismic reflection data sets with widely distributed profiles to extend the results of previous work. We identify a NE-SW zone of recent high-angle faulting and shallow sediment deformation crossing the Seattle Uplift and the Seattle Basin that segments the Seattle Fault Zone and is distinct from previously mapped fault systems. Faults in this zone cut or deform sediments at the seafloor, and the zone trends across the central Puget Lowland at an oblique angle to major regional structures. Two additional zones of faulting trend NW-SE and cut through the Seattle Basin and the Kingston Arch, respectively. Aeromagnetic lineations extend the NE-SW trend of deformation across the Seattle Uplift and connect deformation of shallow sediment in the Puget Sound with deformation of shallow sediment in the Hood Canal. These oblique fault structures may partially control the wide distribution of seismicity within the central Puget Lowland and should be considered in seismic hazard assessments.

  5. Communication-based fault handling scheme for ungrounded distribution systems

    International Nuclear Information System (INIS)

    The requirement for high quality and highly reliable power supplies has been increasing as a result of increasing demand for power. At the time of a fault occurrence in a distribution system, some protection method would be dedicated to fault section isolation and service restoration. However, if there are many outage areas when the protection method is performed, it is an inconvenience to the customer. A conventional method to determine a fault section in ungrounded systems requires many successive outage invocations. This paper proposed an efficient fault section isolation method and service restoration method for single line-to-ground fault in an ungrounded distribution system that was faster than the conventional one using the information exchange between connected feeders. The proposed algorithm could be performed without any power supply interruption and could decrease the number of switching operations, so that customers would not experience outages very frequently. The method involved the use of an intelligent communication method and a sequential switching control scheme. The proposed algorithm was also applied in both a single-tie and multi-tie distribution system. This proposed algorithm has been verified through fault simulations in a simple model of ungrounded multi-tie distribution system. The method proposed in this paper was proven to offer more efficient fault identification and much less outage time than the conventional method. The proposed method could contribute to a system design since it is valid in multi-tie systems. 5 refs., 2 tabs., 8 figs

  6. Sandia's fault analysis system for non-DFT designs

    International Nuclear Information System (INIS)

    A toolset is described that is used to do comprehensive fault analysis on Sandia's past, present, and future generation designs. This toolset provides very fast realistic fault simulation at both the gate and switch level, hierarchical fault reporting, and automatic annotation of undetectable faults. The toolset is built around the Mentor Graphics design system and a Mach1000 hardware accelerator from Silicon Solutions. This session describes the work at Sandia National Laboratories' Center for Radiation Hardened Microelectronics (the CRM) in Albuquerque, New Mexico. The CRM designs and manufactures radiation hardened microelectronics for hostile environments. CRM parts are used in satellites, deep space probes, and weapon systems - hence the reliability of these parts must be exceedingly high. Since the yield of a radiation hardened process is inherently low, Sandia must insure high test vector coverage of all detectable faults

  7. Sliding mode based fault detection, reconstruction and fault tolerant control scheme for motor systems.

    Science.gov (United States)

    Mekki, Hemza; Benzineb, Omar; Boukhetala, Djamel; Tadjine, Mohamed; Benbouzid, Mohamed

    2015-07-01

    The fault-tolerant control problem belongs to the domain of complex control systems in which inter-control-disciplinary information and expertise are required. This paper proposes an improved faults detection, reconstruction and fault-tolerant control (FTC) scheme for motor systems (MS) with typical faults. For this purpose, a sliding mode controller (SMC) with an integral sliding surface is adopted. This controller can make the output of system to track the desired position reference signal in finite-time and obtain a better dynamic response and anti-disturbance performance. But this controller cannot deal directly with total system failures. However an appropriate combination of the adopted SMC and sliding mode observer (SMO), later it is designed to on-line detect and reconstruct the faults and also to give a sensorless control strategy which can achieve tolerance to a wide class of total additive failures. The closed-loop stability is proved, using the Lyapunov stability theory. Simulation results in healthy and faulty conditions confirm the reliability of the suggested framework. PMID:25747198

  8. Functional Fault Modeling of a Cryogenic System for Real-Time Fault Detection and Isolation

    Science.gov (United States)

    Ferrell, Bob; Lewis, Mark; Perotti, Jose; Oostdyk, Rebecca; Brown, Barbara

    2010-01-01

    The purpose of this paper is to present the model development process used to create a Functional Fault Model (FFM) of a liquid hydrogen (L H2) system that will be used for realtime fault isolation in a Fault Detection, Isolation and Recover (FDIR) system. The paper explains th e steps in the model development process and the data products required at each step, including examples of how the steps were performed fo r the LH2 system. It also shows the relationship between the FDIR req uirements and steps in the model development process. The paper concl udes with a description of a demonstration of the LH2 model developed using the process and future steps for integrating the model in a live operational environment.

  9. Ground Fault Diagnosctic System for PEP-II

    Science.gov (United States)

    James, Glen; Himel, Tom; Johnson, Ralph

    1997-05-01

    This paper describes a diagnostic system designed into the String Magnet Power Conversion System that localizes magnet or cable ground faults in the PEP-II rings. This system provides online diagnostics that allow the operator/maintenance personnel to identify the magnet string that has the ground fault and the region in the ring where the ground fault exists. Furthermore, it is our goal to identify within 2 adjacent magnets where this fault exists. The system utilizes the existing PEP-II control system with transient digitizers, ADCs to monitor voltages and currents from the DC/DC converters and the voltage across the soft ground resistor at each bulk power supply. Also, the magnet string voltages are monitored in six locations around the ring to provide an adaptive model of the voltage distribution for each for each magnet string. These signals are utilized in a ground fault location algorithm that identifies and displays the magnet string and specific magnet candidate with the ground fault, on the operators console. Wave forms taken during the fault event are also available for examination at the operators console.

  10. Comparing Different Fault Identification Algorithms in Distributed Power System

    Science.gov (United States)

    Alkaabi, Salim

    A power system is a huge complex system that delivers the electrical power from the generation units to the consumers. As the demand for electrical power increases, distributed power generation was introduced to the power system. Faults may occur in the power system at any time in different locations. These faults cause a huge damage to the system as they might lead to full failure of the power system. Using distributed generation in the power system made it even harder to identify the location of the faults in the system. The main objective of this work is to test the different fault location identification algorithms while tested on a power system with the different amount of power injected using distributed generators. As faults may lead the system to full failure, this is an important area for research. In this thesis different fault location identification algorithms have been tested and compared while the different amount of power is injected from distributed generators. The algorithms were tested on IEEE 34 node test feeder using MATLAB and the results were compared to find when these algorithms might fail and the reliability of these methods.

  11. Fault Tolerant Services for Safe In-Car Embedded Systems

    OpenAIRE

    Navet, Nicolas; Simonot-Lion, Françoise

    2005-01-01

    Due to the increasing criticality of the functions in terms of safety, embedded automotive systems must now respect stringent dependability constraints despite the faults that may occur in a very harsh environment. In a context where critical functions are distributed over the network, the communication system plays a major role. First, we discuss the main services and functionalities that a communication system should offer for easying the design of fault-tolerant applications in the automot...

  12. Active tectonics of Himalayan Frontal Fault system

    Science.gov (United States)

    Thakur, V. C.

    2013-04-01

    In the Sub-Himalayan zone, the frontal Siwalik range abuts against the alluvial plain with an abrupt physiographic break along the Himalayan Frontal Thrust (HFT), defining the present-day tectonic boundary between the Indian plate and the Himalayan orogenic prism. The frontal Siwalik range is characterized by large active anticline structures, which were developed as fault propagation and fault-bend folds in the hanging wall of the HFT. Fault scarps showing surface ruptures and offsets observed in excavated trenches indicate that the HFT is active. South of the HFT, the piedmont zone shows incipient growth of structures, drainage modification, and 2-3 geomorphic depositional surfaces. In the hinterland between the HFT and the MBT, reactivation and out-of-sequence faulting displace Late Quaternary-Holocene sediments. Geodetic measurements across the Himalaya indicate a ~100-km-wide zone, underlain by the Main Himalayan Thrust (MHT), between the HFT and the main microseismicity belt to north is locked. The bulk of shortening, 15-20 mm/year, is consumed aseismically at mid-crustal depth through ductile by creep. Assuming the wedge model, reactivation of the hinterland faults may represent deformation prior to wedge attaining critical taper. The earthquake surface ruptures, ≥240 km in length, interpreted on the Himalayan mountain front through paleoseismology imply reactivation of the HFT and may suggest foreland propagation of the thrust belt.

  13. FaultBuster: data driven fault detection and diagnosis for industrial systems

    DEFF Research Database (Denmark)

    Bergantino, Nicola; Caponetti, Fabio; Longhi, Sauro

    2009-01-01

    Efficient and reliable monitoring systems are mandatory to assure the required security standards in industrial complexes. This paper describes the recent developments of FaultBuster, a purely data-driven diagnostic system. It is designed so to be easily scalable to different monitor tasks...

  14. Correlating hardware fault detection information from distributed control systems to isolate and diagnose a fault in pressurised water reactors

    OpenAIRE

    Cilliers, Anthonie Christoffel

    2013-01-01

    Early fault identification systems enable detecting and diagnosing early onset faults or fault causes which allow maintenance planning on the equipment showing signs of deterioration or failure. This includes valve and leaks and small cracks in steam generator tubes usually detected by means of ultrasonic inspection. We have shown (Cilliers and Mulder, 2012) that detecting faults early during transient operation in NPPs is possible when coupled with a reliable reference to compare plant measu...

  15. Robust fault diagnosis for a class of nonlinear systems with time delay

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Robust fault diagnosis problems based on adaptive observer technique are studied for a class of time delayed nonlinear system with external disturbance. Adaptive fault updating laws were designed to estimate the fault and to guarantee the stability of the diagnosis system. The effects of adjusting parameters in adaptive fault updating laws on the fault estimation accuracy were analyzed. For a designed fault diagnosis system, the super bounds of the state estimation error and fault estimation error of the adaptive observer were discussed, which further showed how the parameters in the adaptive fault updating laws influenced the fault estimation accuracy.Simulation example demonstrates the effectiveness of the proposed methods and the analysis results.

  16. Active Fault Tolerant Control of Livestock Stable Ventilation System

    DEFF Research Database (Denmark)

    Gholami, Mehdi

    2011-01-01

    of the hybrid model are estimated by a recursive estimation algorithm, the Extended Kalman Filter (EKF), using experimental data which was provided by an equipped laboratory. Two methods for active fault diagnosis are proposed. The AFD methods excite the system by injecting a so-called excitation...... degraded performance even in the faulty case. In this thesis, we have designed such controllers for climate control systems for livestock buildings in three steps: Deriving a model for the climate control system of a pig-stable. Designing a active fault diagnosis (AFD) algorithm for different kinds of...... fault. Designing a fault tolerant control scheme for the climate control system. In the first step, a conceptual multi-zone model for climate control of a live-stock building is derived. The model is a nonlinear hybrid model. Hybrid systems contain both discrete and continuous components. The parameters...

  17. PCA Fault Feature Extraction in Complex Electric Power Systems

    Directory of Open Access Journals (Sweden)

    ZHANG, J.

    2010-08-01

    Full Text Available Electric power system is one of the most complex artificial systems in the world. The complexity is determined by its characteristics about constitution, configuration, operation, organization, etc. The fault in electric power system cannot be completely avoided. When electric power system operates from normal state to failure or abnormal, its electric quantities (current, voltage and angles, etc. may change significantly. Our researches indicate that the variable with the biggest coefficient in principal component usually corresponds to the fault. Therefore, utilizing real-time measurements of phasor measurement unit, based on principal components analysis technology, we have extracted successfully the distinct features of fault component. Of course, because of the complexity of different types of faults in electric power system, there still exists enormous problems need a close and intensive study.

  18. A Simulator Study of Recovery of HVDC Links Following AC System Faults

    OpenAIRE

    J. Senthil; Padiyar, KR; Sachchidanand, *

    1990-01-01

    This paper presents the simulator study of a two-terminal HVDC system. The various AC system faults to which the study system is subjected are a) remote-three-phase ground fault, b)single-phase-ground fault and three phase ground faults. These faults are applied both at the rectifier and inverter ends. The results of the simulator study are presented to demonstrate the controller performance in the recovery of HVDC link following AC system faults.

  19. Correlating hardware fault detection information from distributed control systems to isolate and diagnose a fault in pressurised water reactors

    International Nuclear Information System (INIS)

    Highlights: ► Attempt was to use available resources at a nuclear plant in a value added fashion. ► Includes plant measurement data and plant training and engineering simulator capabilities. ► Correlating fault detection data for systems to develop of a deterministic fault identifications system. ► After implementing a host of data manipulation algorithms, the results provided more information on the fault than expected. - Abstract: Early fault identification systems enable detecting and diagnosing early onset faults or fault causes which allow maintenance planning on the equipment showing signs of deterioration or failure. This includes valve and leaks and small cracks in steam generator tubes usually detected by means of ultrasonic inspection. We have shown (Cilliers and Mulder, 2012) that detecting faults early during transient operation in NPPs is possible when coupled with a reliable reference to compare plant measurements with during transients. The problem introduced by the distributed application of control systems operating independently to keep the plant operating within the safe operating boundaries was solved by re-introducing the fault information it into the measurement data, thereby improving plant diagnostic performance. This paper introduces the use of improved fault detection information received from all distributed systems in the plant control system and correlating the information to not only detect the fault but also to diagnose it based on the location and magnitude of the fault cause

  20. Study on Missile Intelligent Fault Diagnosis System Based on Fuzzy NN Expert System

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to study intelligent fault diagnosis methods based on fuzzy neural network (NN) expert systemand build up intelligent fault diagnosis for a type of mis-sile weapon system, the concrete implementation of a fuzzyNN fault diagnosis expert system is given in this paper. Based on thorough research of knowledge presentation, theintelligent fault diagnosis system is implemented with artificial intelligence for a large-scale missile weapon equipment.The method is an effective way to perform fuzzy fault diagnosis. Moreover, it provides a new way of the fault diagnosisfor large-scale missile weapon equipment.

  1. Disturbance observer based fault estimation and dynamic output feedback fault tolerant control for fuzzy systems with local nonlinear models.

    Science.gov (United States)

    Han, Jian; Zhang, Huaguang; Wang, Yingchun; Liu, Yang

    2015-11-01

    This paper addresses the problems of fault estimation (FE) and fault tolerant control (FTC) for fuzzy systems with local nonlinear models, external disturbances, sensor and actuator faults, simultaneously. Disturbance observer (DO) and FE observer are designed, simultaneously. Compared with the existing results, the proposed observer is with a wider application range. Using the estimation information, a novel fuzzy dynamic output feedback fault tolerant controller (DOFFTC) is designed. The controller can be used for the fuzzy systems with unmeasurable local nonlinear models, mismatched input disturbances, and measurement output affecting by sensor faults and disturbances. At last, the simulation shows the effectiveness of the proposed methods. PMID:26456728

  2. Use of Fuzzy Logic Systems for Assessment of Primary Faults

    Science.gov (United States)

    Petrović, Ivica; Jozsa, Lajos; Baus, Zoran

    2015-09-01

    In electric power systems, grid elements are often subjected to very complex and demanding disturbances or dangerous operating conditions. Determining initial fault or cause of those states is a difficult task. When fault occurs, often it is an imperative to disconnect affected grid element from the grid. This paper contains an overview of possibilities for using fuzzy logic in an assessment of primary faults in the transmission grid. The tool for this task is SCADA system, which is based on information of currents, voltages, events of protection devices and status of circuit breakers in the grid. The function model described with the membership function and fuzzy logic systems will be presented in the paper. For input data, diagnostics system uses information of protection devices tripping, states of circuit breakers and measurements of currents and voltages before and after faults.

  3. Designing Expert System for Detecting Faults in Cloud Environment

    Directory of Open Access Journals (Sweden)

    Marzieh Shabdiz

    2013-11-01

    Full Text Available Many fault detection techniques for detecting faults in rule bases system have appeared in the literature. These techniques assume that the rule base is static. This paper presents a new approach by designing Expert system for detecting faults in dynamic environment, such as cloud. Cloud resources are usually not only shared by multiple users but are also dynamically re-allocated per demand. Therefore, rules may be added/deleted in response to certain events happening in the integrated system being controlled by the rules. The approach makes use of spanning trees and Complementary sets to check a dynamic rule base for different kinds of faults underlying directed graph and devises a new method with scripting language on web based tools. This is performed as rules are being added to the dynamic rule base one at a time without the need to rebuild the structures and update rules and paths by expert system.

  4. Fault Injection and Monitoring Capability for a Fault-Tolerant Distributed Computation System

    Science.gov (United States)

    Torres-Pomales, Wilfredo; Yates, Amy M.; Malekpour, Mahyar R.

    2010-01-01

    The Configurable Fault-Injection and Monitoring System (CFIMS) is intended for the experimental characterization of effects caused by a variety of adverse conditions on a distributed computation system running flight control applications. A product of research collaboration between NASA Langley Research Center and Old Dominion University, the CFIMS is the main research tool for generating actual fault response data with which to develop and validate analytical performance models and design methodologies for the mitigation of fault effects in distributed flight control systems. Rather than a fixed design solution, the CFIMS is a flexible system that enables the systematic exploration of the problem space and can be adapted to meet the evolving needs of the research. The CFIMS has the capabilities of system-under-test (SUT) functional stimulus generation, fault injection and state monitoring, all of which are supported by a configuration capability for setting up the system as desired for a particular experiment. This report summarizes the work accomplished so far in the development of the CFIMS concept and documents the first design realization.

  5. Andrea Levialdi in Memoriam

    Science.gov (United States)

    Waisman, Dina

    Professor Andrea Levialdi was born in Bologna Italy in 1911, son of a very modest scientist who at the time was active in the socialist ranks. From an early age Levialdi felt the contradictions between the bourgeois environment surrounding him and his family's deep antifascism. He earned a doctorate in mathematics and physics at the University of Rome in 1937 with a dissertation on photoelasticity, methods and applications. Soon after, he was awarded a scholarship for specializing in optics at the Arcetri National Optics Institute (Florence).

  6. Dynamic Performance of STATCOM Under Various Faults in Power System

    Directory of Open Access Journals (Sweden)

    R.krishna sampath , c.kumar

    2012-12-01

    Full Text Available The STATCOM (Synchronous Static Compensator based on voltage source converter (VSC is used for voltage regulation in transmission and distribution system. The STATCOM can rapidly supply dynamic VARs required during system faults for voltage support. Strict requirements of STATCOM losses and total system loss penalty preclude the use of PWM (Pulse-Width Modulation for VSC based STATCOM applications. This constraint of implementing VSC without PWM functionality, results in over-currents and trips of the STATCOM during and after system faults, when its VAR support functionality is most required. In this paper, we propose and develop an “emergency PWM” strategy to prevent over-currents (and trips in the VSC during and after single line to ground system faults, LLLG faults and to ensure that the STATCOM supplies required reactive power. System performance during a nonlinear load connected without any fault is also considered. The Simulation results are shown for a 48-pulse VSC based ± 100 MVAR STATCOM connected to a 2- bus power strategy to prevent VSC over-currents and to supply required reactive power under line to ground system faults.

  7. Advanced Information Processing System - Fault detection and error handling

    Science.gov (United States)

    Lala, J. H.

    1985-01-01

    The Advanced Information Processing System (AIPS) is designed to provide a fault tolerant and damage tolerant data processing architecture for a broad range of aerospace vehicles, including tactical and transport aircraft, and manned and autonomous spacecraft. A proof-of-concept (POC) system is now in the detailed design and fabrication phase. This paper gives an overview of a preliminary fault detection and error handling philosophy in AIPS.

  8. Fault diagnosis system for the Outokumpu flash smelting process

    International Nuclear Information System (INIS)

    Fault diagnosis systems have attracted the growing interest of researchers in a number of engineering areas. The number of applications has increased and successful results are reported widely. This paper presents the results of principal component analysis carried out on the Outokumpu flash smelting process the waste heat boiler being analysed in more detail. The PCA results are evaluated and the configuration of a fault diagnosis system is proposed. (author)

  9. Fault tolerant control of systems with saturations

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2013-01-01

    This paper presents framework for fault tolerant controllers (FTC) that includes input saturation. The controller architecture known from FTC is based on the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization is extended to handle input saturation. Applying this controller architecture in connec...

  10. Fault detection in rotor bearing systems using time frequency techniques

    Science.gov (United States)

    Chandra, N. Harish; Sekhar, A. S.

    2016-05-01

    Faults such as misalignment, rotor cracks and rotor to stator rub can exist collectively in rotor bearing systems. It is an important task for rotor dynamic personnel to monitor and detect faults in rotating machinery. In this paper, the rotor startup vibrations are utilized to solve the fault identification problem using time frequency techniques. Numerical simulations are performed through finite element analysis of the rotor bearing system with individual and collective combinations of faults as mentioned above. Three signal processing tools namely Short Time Fourier Transform (STFT), Continuous Wavelet Transform (CWT) and Hilbert Huang Transform (HHT) are compared to evaluate their detection performance. The effect of addition of Signal to Noise ratio (SNR) on three time frequency techniques is presented. The comparative study is focused towards detecting the least possible level of the fault induced and the computational time consumed. The computation time consumed by HHT is very less when compared to CWT based diagnosis. However, for noisy data CWT is more preferred over HHT. To identify fault characteristics using wavelets a procedure to adjust resolution of the mother wavelet is presented in detail. Experiments are conducted to obtain the run-up data of a rotor bearing setup for diagnosis of shaft misalignment and rotor stator rubbing faults.

  11. Adaptive Vibration Control System for MR Damper Faults

    Directory of Open Access Journals (Sweden)

    Juan C. Tudón-Martínez

    2015-01-01

    Full Text Available Several methods have been proposed to estimate the force of a semiactive damper, particularly of a magnetorheological damper because of its importance in automotive and civil engineering. Usually, all models have been proposed assuming experimental data in nominal operating conditions and some of them are estimated for control purposes. Because dampers are prone to fail, fault estimation is useful to design adaptive vibration controllers to accommodate the malfunction in the suspension system. This paper deals with the diagnosis and estimation of faults in an automotive magnetorheological damper. A robust LPV observer is proposed to estimate the lack of force caused by a damper leakage in a vehicle corner. Once the faulty damper is isolated in the vehicle and the fault is estimated, an Adaptive Vibration Control System is proposed to reduce the fault effect using compensation forces from the remaining healthy dampers. To fulfill the semiactive damper constraints in the fault adaptation, an LPV controller is designed for vehicle comfort and road holding. Simulation results show that the fault observer has good performance with robustness to noise and road disturbances and the proposed AVCS improves the comfort up to 24% with respect to a controlled suspension without fault tolerance features.

  12. Measurement and analysis of operating system fault tolerance

    Science.gov (United States)

    Lee, I.; Tang, D.; Iyer, R. K.

    1992-01-01

    This paper demonstrates a methodology to model and evaluate the fault tolerance characteristics of operational software. The methodology is illustrated through case studies on three different operating systems: the Tandem GUARDIAN fault-tolerant system, the VAX/VMS distributed system, and the IBM/MVS system. Measurements are made on these systems for substantial periods to collect software error and recovery data. In addition to investigating basic dependability characteristics such as major software problems and error distributions, we develop two levels of models to describe error and recovery processes inside an operating system and on multiple instances of an operating system running in a distributed environment. Based on the models, reward analysis is conducted to evaluate the loss of service due to software errors and the effect of the fault-tolerance techniques implemented in the systems. Software error correlation in multicomputer systems is also investigated.

  13. Soft-Fault Detection Technologies Developed for Electrical Power Systems

    Science.gov (United States)

    Button, Robert M.

    2004-01-01

    The NASA Glenn Research Center, partner universities, and defense contractors are working to develop intelligent power management and distribution (PMAD) technologies for future spacecraft and launch vehicles. The goals are to provide higher performance (efficiency, transient response, and stability), higher fault tolerance, and higher reliability through the application of digital control and communication technologies. It is also expected that these technologies will eventually reduce the design, development, manufacturing, and integration costs for large, electrical power systems for space vehicles. The main focus of this research has been to incorporate digital control, communications, and intelligent algorithms into power electronic devices such as direct-current to direct-current (dc-dc) converters and protective switchgear. These technologies, in turn, will enable revolutionary changes in the way electrical power systems are designed, developed, configured, and integrated in aerospace vehicles and satellites. Initial successes in integrating modern, digital controllers have proven that transient response performance can be improved using advanced nonlinear control algorithms. One technology being developed includes the detection of "soft faults," those not typically covered by current systems in use today. Soft faults include arcing faults, corona discharge faults, and undetected leakage currents. Using digital control and advanced signal analysis algorithms, we have shown that it is possible to reliably detect arcing faults in high-voltage dc power distribution systems (see the preceding photograph). Another research effort has shown that low-level leakage faults and cable degradation can be detected by analyzing power system parameters over time. This additional fault detection capability will result in higher reliability for long-lived power systems such as reusable launch vehicles and space exploration missions.

  14. Architecture and Segmentation of Strike-Slip Faults in Southern California

    Science.gov (United States)

    Sahakian, Valerie Jean

    This dissertation investigates the architecture and segmentation of fault structures in Southern California, using marine active-source seismic data. Onshore or marine fault geometry is often poorly constrained due to their location. This study employs marine active-source seismic data to image these structures, and further the current understanding of the hazards they pose to the region. With these data, this dissertation first improves the existing framework of knowledge of fault architecture in the Salton pull-apart basin, near the terminus of the Southern San Andreas Fault (SSAF). It investigates the evolution of the pull-apart basin in the Imperial-San Andreas fault system with reflection and refraction data, and provides important constraints regarding the interplay of faults and strain partitioning in this region. New data suggest the existence of a previously unknown fault in the Salton Sea, the Salton Trough Fault (STF). This transtensional fault is located just to the west of the eastern Salton Sea shoreline, and strikes approximately parallel to the SSAF terminus. Finally, this dissertation investigates the architecture and segmentation of the Newport-Inglewood/Rose Canyon (NIRC) fault zone offshore Southern California, using seismic data sets with unprecedented density and resolution. It identifies four main fault strands, with three main stepover boundaries, and presents possible rupture scenarios based on quantitative and qualitative assessments of throughgoing rupture at stepovers or segment boundaries.

  15. Fault tolerant hypercube computer system architecture

    Science.gov (United States)

    Madan, Herb S. (Inventor); Chow, Edward (Inventor)

    1989-01-01

    A fault-tolerant multiprocessor computer system of the hypercube type comprising a hierarchy of computers of like kind which can be functionally substituted for one another as necessary is disclosed. Communication between the working nodes is via one communications network while communications between the working nodes and watch dog nodes and load balancing nodes higher in the structure is via another communications network separate from the first. A typical branch of the hierarchy reporting to a master node or host computer comprises, a plurality of first computing nodes; a first network of message conducting paths for interconnecting the first computing nodes as a hypercube. The first network provides a path for message transfer between the first computing nodes; a first watch dog node; and a second network of message connecting paths for connecting the first computing nodes to the first watch dog node independent from the first network, the second network provides an independent path for test message and reconfiguration affecting transfers between the first computing nodes and the first switch watch dog node. There is additionally, a plurality of second computing nodes; a third network of message conducting paths for interconnecting the second computing nodes as a hypercube. The third network provides a path for message transfer between the second computing nodes; a fourth network of message conducting paths for connecting the second computing nodes to the first watch dog node independent from the third network. The fourth network provides an independent path for test message and reconfiguration affecting transfers between the second computing nodes and the first watch dog node; and a first multiplexer disposed between the first watch dog node and the second and fourth networks for allowing the first watch dog node to selectively communicate with individual ones of the computing nodes through the second and fourth networks; as well as, a second watch dog node

  16. A Diagnostic System for Speed-Varying Motor Rotary Faults

    Directory of Open Access Journals (Sweden)

    Chwan-Lu Tseng

    2014-01-01

    Full Text Available This study proposed an intelligent rotary fault diagnostic system for motors. A sensorless rotational speed detection method and an improved dynamic structural neural network are used. Moreover, to increase the convergence speed of training, a terminal attractor method and a hybrid discriminant analysis are also adopted. The proposed method can be employed to detect the rotary frequencies of motors with varying speeds and can enhance the discrimination of motor faults. To conduct the experiments, this study used wireless sensor nodes to transmit vibration data and employed MATLAB to write codes for functional modules, including the signal processing, sensorless rotational speed estimation, neural network, and stochastic process control chart. Additionally, Visual Basic software was used to create an integrated human-machine interface. The experimental results regarding the test of equipment faults indicated that the proposed novel diagnostic system can effectively estimate rotational speeds and provide superior ability of motor fault discrimination with fast training convergence.

  17. Development of an advanced transmission line fault location system

    International Nuclear Information System (INIS)

    This paper describes the solution techniques, system modeling considerations, and simulation studies performed as a part of the development of an advanced transmission line fault location system (AFLS) intended for use on the New York Power Authority's system. The Power Authority's Moses-Adirondack 230 kV lines were selected as a test bed for the study. A reduced model of the transmission system around the Moses-Adirondack lines was developed, and a number of Electromagnetic Transients Program (EMTP) cases run to establish simulated voltage and current information as fed to the fault location system. Sensitivity studies were performed to investigate the impact of various system models, hardware features, and system conditions on fault location accuracy

  18. A Diagnostic System for Speed-Varying Motor Rotary Faults

    OpenAIRE

    2014-01-01

    This study proposed an intelligent rotary fault diagnostic system for motors. A sensorless rotational speed detection method and an improved dynamic structural neural network are used. Moreover, to increase the convergence speed of training, a terminal attractor method and a hybrid discriminant analysis are also adopted. The proposed method can be employed to detect the rotary frequencies of motors with varying speeds and can enhance the discrimination of motor faults. To conduct the experime...

  19. Model Based Fault Isolation for Object-Oriented Control Systems

    OpenAIRE

    Larsson, Magnus; Klein, Inger; Lawesson, Dan; Nilsson, Ulf

    1999-01-01

    This report addresses the problem of fault propagation between software modules in a large industrial control system with anobject oriented architecture. There exists a conflict between object-oriented design goals such as encapsulation and modularity, and the possibility to suppress propagating error conditions. When an object detects an error condition, it is not desirable toperform the extensive querying of other objects that would be necessary to decide how close to the real fault the obj...

  20. Robust Fault Diagnosis for Systems with Electronic Induced Delays

    OpenAIRE

    Fonod, Robert; Henry, David; Bornschlegl, Eric; Charbonnel, Catherine

    2012-01-01

    A problem of robust fault diagnosis of digital controlled continuous-time systems with uncertain time-varying input delay is studied in this paper. Two residual-based fault detection and isolation (FDI) schemes are proposed that are robust in terms of time-varying delays induced by the electronic devices and disturbances. The idea of both proposed methods is to transform the uncertainty caused by delays into unknown inputs and decouple them by means of eigenstructure assignment (EA) technique...

  1. Fault Diagnosis and Accommodation of LTI systems by modified Youla parameterization

    Directory of Open Access Journals (Sweden)

    Minupriya A

    2012-06-01

    Full Text Available In this paper an Active Fault Tolerant Control (FTC scheme is proposed for Linear Time Invariant (LTI systems, which achieves fault diagnosis followed by fault accommodation. The fault diagnosis scheme is carried out in two steps; Fault detection followed by Fault isolation. Fault detection filter use the sensor measurements to generate residuals, which have a unique static pattern in response to each fault. Distortion in these static patterns generates the probability of the presence of fault. The fault accommodation scheme is carried out using the Generalized Internal Model Control (GIMC architecture, also known as modified Youla parameterization. In addition, performance indices are also evaluated to indicate that the resulting fault tolerant scheme can detect, identify and accommodate actuator and sensor faults under additive faults. The DC motor example is considered for the demonstration of the proposed scheme.

  2. Study on fault locating technology for satellite power system

    Institute of Scientific and Technical Information of China (English)

    LONG Bing; JIANG Xing-wei; SONG Zheng-ji

    2005-01-01

    It is currently prevalent to locate faults for a satellite power system based on an expert system, not utilizing all the available information provided by tests. The casual network model for a satellite power system is presented. Considerations for failure probability of each component of the power system, the cost of applying each test, the influence of a precedent test result on the next test selection, and an optimal sequential testing algorithm for fault location is presented. This program is applied to locate the failure component of the power system of a satellite. The results show this program is very effective and it is very fast to generate an optimal diagnosis tree.

  3. Fault diagnosis and fault-tolerant control strategies for non-linear systems analytical and soft computing approaches

    CERN Document Server

    Witczak, Marcin

    2014-01-01

      This book presents selected fault diagnosis and fault-tolerant control strategies for non-linear systems in a unified framework. In particular, starting from advanced state estimation strategies up to modern soft computing, the discrete-time description of the system is employed Part I of the book presents original research results regarding state estimation and neural networks for robust fault diagnosis. Part II is devoted to the presentation of integrated fault diagnosis and fault-tolerant systems. It starts with a general fault-tolerant control framework, which is then extended by introducing robustness with respect to various uncertainties. Finally, it is shown how to implement the proposed framework for fuzzy systems described by the well-known Takagi–Sugeno models. This research monograph is intended for researchers, engineers, and advanced postgraduate students in control and electrical engineering, computer science,as well as mechanical and chemical engineering.

  4. Fault Diagnosis Scheme for Nonlinear Stochastic Hybrid Systems With Time-Varying Fault

    Czech Academy of Sciences Publication Activity Database

    Nguyen, H.Q.; Čelikovský, Sergej

    Lima: Tarea Asociación Gráfica Educativa, Lima, Peru, 2012, s. 1-7. ISBN 978-612-4057-71-7. [15th Latinamerican Control Conference CLCA 2012. Lima (PE), 23.10.2012-26.10.2012] Institutional support: RVO:67985556 Keywords : Fault detection and diagnosis * nonlinear stochastic hybrid system * B-spline functions * probability density function(PDF) Subject RIV: BC - Control Systems Theory

  5. Fault tolerance control for proton exchange membrane fuel cell systems

    Science.gov (United States)

    Wu, Xiaojuan; Zhou, Boyang

    2016-08-01

    Fault diagnosis and controller design are two important aspects to improve proton exchange membrane fuel cell (PEMFC) system durability. However, the two tasks are often separately performed. For example, many pressure and voltage controllers have been successfully built. However, these controllers are designed based on the normal operation of PEMFC. When PEMFC faces problems such as flooding or membrane drying, a controller with a specific design must be used. This paper proposes a unique scheme that simultaneously performs fault diagnosis and tolerance control for the PEMFC system. The proposed control strategy consists of a fault diagnosis, a reconfiguration mechanism and adjustable controllers. Using a back-propagation neural network, a model-based fault detection method is employed to detect the PEMFC current fault type (flooding, membrane drying or normal). According to the diagnosis results, the reconfiguration mechanism determines which backup controllers to be selected. Three nonlinear controllers based on feedback linearization approaches are respectively built to adjust the voltage and pressure difference in the case of normal, membrane drying and flooding conditions. The simulation results illustrate that the proposed fault tolerance control strategy can track the voltage and keep the pressure difference at desired levels in faulty conditions.

  6. Fault sensitivity and wear-out analysis of VLSI systems

    Science.gov (United States)

    Choi, Gwan Seung

    1994-07-01

    This thesis describes simulation approaches to conduct fault sensitivity and wear-out failure analysis of VLSI systems. A fault-injection approach to study transient impact in VLSI systems is developed. Through simulated fault injection at the device level and, subsequent fault propagation at the gate functional and software levels, it is possible to identify critical bottlenecks in dependability. Techniques to speed up the fault simulation and to perform statistical analysis of fault-impact are developed. A wear-out simulation environment is also developed to closely mimic dynamic sequences of wear-out events in a device through time, to localize weak location/aspect of target chip and to allow generation of TTF (Time-to-failure) distribution of VLSI chip as a whole. First, an accurate simulation of a target chip and its application code is performed to acquire trace data (real workload) on switch activity. Then, using this switch activity information, wear-out of the each component in the entire chip is simulated using Monte Carlo techniques.

  7. Active Fault Diagnosis in Sampled-data Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2015-01-01

    The focus in this paper is on active fault diagnosis (AFD) in closed-loop sampleddata systems. Applying the same AFD architecture as for continuous-time systems does not directly result in the same set of closed-loop matrix transfer functions. For continuous-time systems, the LFT (linear fractional...

  8. Diagnosis and Fault-Tolerant Control for Thruster-Assisted Position Mooring System

    DEFF Research Database (Denmark)

    Nguyen, Trong Dong; Blanke, Mogens; Sørensen, Asgeir

    2007-01-01

    Development of fault-tolerant control systems is crucial to maintain safe operation of o®shore installations. The objective of this paper is to develop a fault- tolerant control for thruster-assisted position mooring (PM) system with faults occurring in the mooring lines. Faults in line's pretens......Development of fault-tolerant control systems is crucial to maintain safe operation of o®shore installations. The objective of this paper is to develop a fault- tolerant control for thruster-assisted position mooring (PM) system with faults occurring in the mooring lines. Faults in line......'s pretension or line breaks will degrade the performance of the positioning of the vessel. Faults will be detected and isolated through a fault diagnosis procedure. When faults are detected, they can be accommodated through the control action in which only parameter of the controlled plant has to be updated to...

  9. Software fault tree analysis of an automated control system device written in Ada

    OpenAIRE

    Winter, Mathias William.

    1995-01-01

    Software Fault Tree Analysis (SFTA) is a technique used to analyze software for faults that could lead to hazardous conditions in systems which contain software components. Previous thesis works have developed three Ada-based, semi-automated software analysis tools, the Automated Code Translation Tool (ACm) an Ada statement template generator, the Fault Tree Editor (Fm) a graphical fault tree editor, and the Fault Isolator (Fl) an automated software fault tree isolator. These previous works d...

  10. Fault Analysis of ITER Coil Power Supply System

    International Nuclear Information System (INIS)

    The ITER magnet coils are all designed using superconductors with high current carrying capability. The Toroidal Field (TF) coils operate in a steadystate mode with a current of 68 kA and discharge the stored energy in case of quench with using 9 interleaved Fast Discharge Units (FDUs). The Central Solenoid (CS) coils and Poloidal Field (PF) coils operate in a pulse mode with currents of up to 45 kA and require fast variation of currents inducing more than 10 kV during normal operation on the coil terminals using Switching Network (SN) systems (CSs, PF1 and 6) and Booster and VS converters (PF2 to 5), which are series connected to Main converters. SN and FDU systems comprise high current DC circuit breakers and resistors for generating high voltage (SN) and to dissipate magnetic energy (FDUs). High transient voltages can arise due to the switching operation of SN and FD and the characteristics of resistors and stray components of DC distribution systems. Also, faults in power supply control such as shorts or grounding faults can produce higher voltages between terminals and between terminal and ground. Therefore, the design of the coil insulation, coil terminal regions, feeders, feed throughs, pipe breaks and instrumentation must take account of these high voltages during normal and abnormal conditions. Voltage insulation level can be defined and it is necessary to test the coils at higher voltages, to be sure of reliable performance during the lifetime of operation. This paper describes the fault analysis of the TF, CS and PF coil power supply systems, taking account of the stray parameter of the power supply and switching systems and inductively coupled superconducting coil models. Resistor grounding systems are included in the simulation model and all fault conditions such as converter hardware and software faults, switching system hardware and software faults, DC short circuits and single grounding faults are simulated. The occurrence of two successive faults

  11. Sensor fault estimation filter design for discrete-time linear time-varying systems

    OpenAIRE

    Wang, Zhenhua; Rodrigues, Mickael; Theilliol, Didier; Shen, Yi

    2014-01-01

    This paper proposes a sensor fault diagnosis method for a class of discrete-time linear time-varying (LTV) systems. In this paper, the considered system is rstly formulated as a de- scriptor system representation by considering the sensor faults as auxiliary state variables. Based on the descriptor system model, a fault estimation lter which can simultaneously estimate the state and the sensor fault magnitudes is designed via a minimum- variance principle. Then, a fault diagnosis scheme is pr...

  12. Generalised strategy for implementing the minimum fault reactance based fault location algorithm in real power distribution systems

    Directory of Open Access Journals (Sweden)

    E. Correa-Tapasco

    2011-10-01

    Full Text Available The paper presented here is aimed at proposing a generalised strategy for easily implementing a fault locator in real power distribution systems. The strategy is based on the definition of a fault location method and its successive application along section lines from a power substation to the section where the fault has been determined. According to the results, the proposed strategy seems to be applicable to real power systems as an alternative for reducing fault location time and thus keeping good continuity indexes.

  13. Inter Processor Communication for Fault Diagnosis in Multiprocessor Systems

    Directory of Open Access Journals (Sweden)

    C. D. Malleswar

    1994-04-01

    Full Text Available In the preseJlt paper a simple technique is proposed for fault diagnosis for multiprocessor and multiple system environments, wherein all microprocessors in the system are used in part to check the health of their neighbouring processors. It involves building simple fail-safe serial communication links between processors. Processors communicate with each other over these links and each processor is made to go through certain sequences of actions intended for diagnosis, under the observation of another processor .With limited overheads, fault detection can be done by this method. Also outlined are some of the popular techniques used for health check of processor-based systems.

  14. Fault-tolerant Control Systems-An Introductory Overview

    Institute of Scientific and Technical Information of China (English)

    Jin Jiang

    2005-01-01

    This paper presents an introductory overview on the development of fault-tolerant control systems. For this reason, the paper is written in a tutorial fashion to summarize some of the important results in this subject area deliberately without going into details in any of them. However, key references are provided from which interested readers can obtain more detailed information on a particular subject. It is necessary to mention that, throughout this paper, no efforts were made to provide an exhaustive coverage on the subject matter. In fact, it is far from it. The paper merely represents the view and experience of its author. It can very well be that some important issues or topics were left out unintentionally. If that is the case, the author sincerely apologizes in advance.After a brief account of fault-tolerant control systems, particularly on the original motivations, and the concept of redundancies, the paper reviews the development of fault-tolerant control systems with highlights to several important issues from a historical perspective. The general approaches to fault-tolerant control has been divided into passive, active, and hybrid approaches. The analysis techniques for active fault-tolerant control systems are also discussed. Practical applications of faulttolerant control are highlighted from a practical and industrial perspective. Finally, some critical issues in this area are discussed as open problems for future research/development in this emerging field.

  15. Design of fault tolerant control system for steam generator using

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myung Ki; Seo, Mi Ro [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    A controller and sensor fault tolerant system for a steam generator is designed with fuzzy logic. A structure of the proposed fault tolerant redundant system is composed of a supervisor and two fuzzy weighting modulators. A supervisor alternatively checks a controller and a sensor induced performances to identify which part, a controller or a sensor, is faulty. In order to analyze controller induced performance both an error and a change in error of the system output are chosen as fuzzy variables. The fuzzy logic for a sensor induced performance uses two variables : a deviation between two sensor outputs and its frequency. Fuzzy weighting modulator generates an output signal compensated for faulty input signal. Simulations show that the proposed fault tolerant control scheme for a steam generator regulates well water level by suppressing fault effect of either controllers or sensors. Therefore through duplicating sensors and controllers with the proposed fault tolerant scheme, both a reliability of a steam generator control and sensor system and that of a power plant increase even more. 2 refs., 9 figs., 1 tab. (Author)

  16. Experimental study on superconducting fault current limiting transformer for fault current suppression and system stability improvement

    Science.gov (United States)

    Kagawa, H.; Hayakawa, N.; Kashima, N.; Nagaya, S.; Okubo, H.

    2002-08-01

    We have been developing a superconducting fault current limiting transformer (SFCLT) with 3-phase, 500/275 kV, 625 MVA and optimized the main parameters by EMTP simulation. In this paper, we designed and fabricated an experimental scale-down model of SFCLT with 3-phase, 275/105 V, 6.25 kVA, using NbTi superconducting wire. We introduced the experimental model SFCLT into a transient network analyzer consisted of synchronous generators, transformers, transmission lines, circuit breakers and an infinite bus. It was revealed that experimental model had effective function-parameters as was simulated and experimental results clarified the effectiveness of SFCLT having both functions of the fault current suppression and the system stability improvement in a future superconducting power system.

  17. An enhanced approach to actuator fault estimation design for linear continuous-time systems

    International Nuclear Information System (INIS)

    An enhanced approach to fault estimation systems design, adjusted for linear continuous-time systems, is proposed in the paper. Based on LMI principle the method exploits state-space observer principle in an adaptive fault estimation scheme for single actuator faults. A simulation example, subject to different type of failures, demonstrates the effectiveness of the proposed form of the fault estimation technique

  18. Efficient Fault Tree Analysis of Complex Fault Tolerant Multiple-Phased Systems

    Institute of Scientific and Technical Information of China (English)

    MO Yuchang; LIU Hongwei; YANG Xiaozong

    2007-01-01

    Fault tolerant multiple phased systems (FTMPS), i.e., systems whose critical components are independently replicated and whose operational life can be partitioned in a set of disjoint periods, are called "phases". Because of their deployment in critical applications, their reliability analysis is a task of primary relevance to validate the designs. Fault tree analysis based on binary decision diagram (BDD) is one of the most commonly used techniques for FTMPS reliability analysis. To utilize the technique the fault tree structure of FTMPS needs to be converted into the corresponding BDD format. Our research work shows that the system BDD generation algorithms presented in the literature are too inefficient to be used for industrial complex FTPMS because of the problems, such as variable ordering and combination of large BDDs. This paper presents a more efficient approach consisting of a flatting pre-processing technique, a proved efficient ordering heuristic and a bottom-up generation algorithm. The approach tries to combine share-variable BDDs by complex combination operation firstly and then combine no-share-variable BDDs using simple combination operation, thus to alvoid the intensive computations caused by large BDD combination operations. An example FTMPS is analyzed to illustrate the advantages of our approach.

  19. Online fault location on crossbonded AC cables in underground transmission systems

    OpenAIRE

    F. Jensen, Christian; Bak, Claus Leth; Gudmundsdottir, Unnur Stella

    2014-01-01

    In this paper, a fault locator system specifically designed for crossbonded cables is described. Electromagnetic wave propagation theory for crossbonded cables with focus on fault location purposes is discussed. Based on this, the most optimal modal component and input signal to the fault locator system are identified. The fault locator system uses the Wavelet Transform both to create reliable triggers in the units and to estimate the fault location based on time domain signals obtained in th...

  20. Fault Diagnosis in Dynamic Systems Using Fuzzy Interacting Observers

    Directory of Open Access Journals (Sweden)

    N. V. Kolesov

    2013-01-01

    Full Text Available A method of fault diagnosis in dynamic systems based on a fuzzy approach is proposed. The new method possesses two basic specific features which distinguish it from the other known fuzzy methods based on the application of fuzzy logic and a bank of state observers. First, this method uses a bank of interacting observers instead of traditional independent observers. The second specific feature of the proposed method is the assumption that there is no strict boundary between the serviceable and disabled technical states of the system, which makes it possible to specify a decision making rule for fault diagnosis.

  1. Testing Virtual Reconfigurable Circuit Designed For A Fault Tolerant System

    Directory of Open Access Journals (Sweden)

    P. N. Kumar

    2007-01-01

    Full Text Available This research describes about the testing of virtual reconfigurable circuit (VRC designed and implemented for a fault tolerant system which averages the (three sensor inputs. The circuits that are to be tested are those which are successfully evolved in this system under different situations such as (i all the three sensors are faultless (ii one of the input sensor fails as open (iii sensors fails as short circuit. The objective of this research is to test the desired optimal circuits evolved by decoding the configuration bit streams. The logic simulation tool used to perform fault simulation is AUSIM (Auburn University Simulator.

  2. Effect analysis of faults in digital I and C systems of nuclear power plants

    International Nuclear Information System (INIS)

    A reliability analysis of digital instrumentation and control (I and C) systems in nuclear power plants has been introduced as one of the important elements of a probabilistic safety assessment because of the unique characteristics of digital I and C systems. Digital I and C systems have various features distinguishable from those of analog I and C systems such as software and fault-tolerant techniques. In this work, the faults in a digital I and C system were analyzed and a model for representing the effects of the faults was developed. First, the effects of the faults in a system were analyzed using fault injection experiments. A software-implemented fault injection technique in which faults can be injected into the memory was used based on the assumption that all faults in a system are reflected in the faults in the memory. In the experiments, the effect of a fault on the system output was observed. In addition, the success or failure in detecting the fault by fault-tolerant functions included in the system was identified. Second, a fault tree model for representing that a fault is propagated to the system output was developed. With the model, it can be identified how a fault is propagated to the output or why a fault is not detected by fault-tolerant techniques. Based on the analysis results of the proposed method, it is possible to not only evaluate the system reliability but also identify weak points of fault-tolerant techniques by identifying undetected faults. The results can be reflected in the designs to improve the capability of fault-tolerant techniques. (author)

  3. Managing systems faults on the commercial flight deck: Analysis of pilots' organization and prioritization of fault management information

    Science.gov (United States)

    Rogers, William H.

    1993-01-01

    In rare instances, flight crews of commercial aircraft must manage complex systems faults in addition to all their normal flight tasks. Pilot errors in fault management have been attributed, at least in part, to an incomplete or inaccurate awareness of the fault situation. The current study is part of a program aimed at assuring that the types of information potentially available from an intelligent fault management aiding concept developed at NASA Langley called 'Faultfinde' (see Abbott, Schutte, Palmer, and Ricks, 1987) are an asset rather than a liability: additional information should improve pilot performance and aircraft safety, but it should not confuse, distract, overload, mislead, or generally exacerbate already difficult circumstances.

  4. Influences of Resistor-Type Superconducting Fault Current Limiter on Power System Transient Stability with Asymmetrical Short-Circuit Faults

    Institute of Scientific and Technical Information of China (English)

    Xue-Ping Gu; Zhi-Long Yang

    2008-01-01

    The transient stability of a single machine to infinite-busbar power system with resistor- type superconducting fault current limiters (SFCL) is analyzed under asymmetrical short-circuit fault conditions. The SFCL is considered to introduce a resistance into the three-phase circuits when faults occur. Based on the power-angle curves for different short-circuit conditions of the single-line to ground, double-line to ground and line to line short-circuit faults, the influences of the SFCLs on transient stability are analyzed in detail. The time-domain simulation of transient stability is carried out to verify the analytical results.

  5. FADES: A tool for automated fault analysis of complex systems

    International Nuclear Information System (INIS)

    FADES is an Expert System for performing fault analyses on complex connected systems. By using a graphical editor to draw components and link them together the FADES system allows the analyst to describe a given system. The knowledge base created is used to qualitatively simulate the system behaviour. By inducing all possible component failures in the system and determining their effects, a set of facts is built up. These facts are then used to create Fault Trees, or FMEA tables. The facts may also be used for explanation effects and to generate diagnostic rules allowing system instrumentation to be optimised. The prototype system has been built and tested and is preently undergoing testing by users. All comments from these trials will be used to tailor the system to the requirements of the user so that the end product performs the exact task required

  6. Fault trees for decision making in systems analysis

    International Nuclear Information System (INIS)

    The application of fault tree analysis (FTA) to system safety and reliability is presented within the framework of system safety analysis. The concepts and techniques involved in manual and automated fault tree construction are described and their differences noted. The theory of mathematical reliability pertinent to FTA is presented with emphasis on engineering applications. An outline of the quantitative reliability techniques of the Reactor Safety Study is given. Concepts of probabilistic importance are presented within the fault tree framework and applied to the areas of system design, diagnosis and simulation. The computer code IMPORTANCE ranks basic events and cut sets according to a sensitivity analysis. A useful feature of the IMPORTANCE code is that it can accept relative failure data as input. The output of the IMPORTANCE code can assist an analyst in finding weaknesses in system design and operation, suggest the most optimal course of system upgrade, and determine the optimal location of sensors within a system. A general simulation model of system failure in terms of fault tree logic is described. The model is intended for efficient diagnosis of the causes of system failure in the event of a system breakdown. It can also be used to assist an operator in making decisions under a time constraint regarding the future course of operations. The model is well suited for computer implementation. New results incorporated in the simulation model include an algorithm to generate repair checklists on the basis of fault tree logic and a one-step-ahead optimization procedure that minimizes the expected time to diagnose system failure. (80 figures, 20 tables)

  7. A System for Fault Management and Fault Consequences Analysis for NASA's Deep Space Habitat

    Science.gov (United States)

    Colombano, Silvano; Spirkovska, Liljana; Baskaran, Vijaykumar; Aaseng, Gordon; McCann, Robert S.; Ossenfort, John; Smith, Irene; Iverson, David L.; Schwabacher, Mark

    2013-01-01

    NASA's exploration program envisions the utilization of a Deep Space Habitat (DSH) for human exploration of the space environment in the vicinity of Mars and/or asteroids. Communication latencies with ground control of as long as 20+ minutes make it imperative that DSH operations be highly autonomous, as any telemetry-based detection of a systems problem on Earth could well occur too late to assist the crew with the problem. A DSH-based development program has been initiated to develop and test the automation technologies necessary to support highly autonomous DSH operations. One such technology is a fault management tool to support performance monitoring of vehicle systems operations and to assist with real-time decision making in connection with operational anomalies and failures. Toward that end, we are developing Advanced Caution and Warning System (ACAWS), a tool that combines dynamic and interactive graphical representations of spacecraft systems, systems modeling, automated diagnostic analysis and root cause identification, system and mission impact assessment, and mitigation procedure identification to help spacecraft operators (both flight controllers and crew) understand and respond to anomalies more effectively. In this paper, we describe four major architecture elements of ACAWS: Anomaly Detection, Fault Isolation, System Effects Analysis, and Graphic User Interface (GUI), and how these elements work in concert with each other and with other tools to provide fault management support to both the controllers and crew. We then describe recent evaluations and tests of ACAWS on the DSH testbed. The results of these tests support the feasibility and strength of our approach to failure management automation and enhanced operational autonomy

  8. STUDY OF A FAULT DIAGNOSIS EXPERT SYSTEM FOR SYNTHETIC MINING SYSTEM HYDRAULIC SUPPORT

    Institute of Scientific and Technical Information of China (English)

    Han Yilun

    2000-01-01

    Fault diagnosis expert system for hydraulic support is studied.The system is achieved by Turbo-prolong Language, it summaries the experience of the domain expert and sets up a fault tree, knowledge base is developed by a productive rule.According to the feature of diagnosis, the system selects forward non-determination inferring and limited depth-first search strategy.It can accomplish expert diagnosis of more than 50 kinds faults in hydraulic support.

  9. PCA Fault Feature Extraction in Complex Electric Power Systems

    OpenAIRE

    ZHANG, J.; Z. Wang; Zhang, Y.; J. MA

    2010-01-01

    Electric power system is one of the most complex artificial systems in the world. The complexity is determined by its characteristics about constitution, configuration, operation, organization, etc. The fault in electric power system cannot be completely avoided. When electric power system operates from normal state to failure or abnormal, its electric quantities (current, voltage and angles, etc.) may change significantly. Our researches indicate that the variable with the biggest coeffic...

  10. Neotectonics of the Periadriatic Fault System (Eastern and Southern Alps)

    Science.gov (United States)

    Garcia, Sebastian; Handy, Mark R.; Rosenberg, Claudio L.

    2010-05-01

    The Periadriatic Fault System (PFS) is the surface trace of the leading edge of the present Adriatic microplate, which has indented the European lithosphere since at least Miocene time. The PFS is also the tectonic boundary between the Southern Alps with its S-directed fold-and-thrust belt and the rest of the Alps that experienced Cretaceous and Tertiary metamorphism and deformation. In contrast to other Oligo-Miocene faults in the Eastern Alps (Engadine, Brenner and Inntal faults, Friuli-Trieste and the Giudicarie thrust systems) the PFS is seismically silent. In reassessing recent GPS data of Devoti et al. [2008], we find that the northward component of Adriatic motion is accommodated primarily by the Friuli-Trieste and Giudicarie thrust belts. This is manifested by a step-like decrease of the northward-component of Adriatic convergence and a drastic reduction in the seismic activity going from south to north along the Giudicarie belt. Nevertheless, the PFS may still be active, as indicated by an M=4.8 earthquake in 2001 near Merano. Geochronological ages show no evidence for tectonic movements younger than mid-Miocene along the PFS, except along the Giudicarie thrust system where exhumation rates have increased since the Messinian [Martin et al., 1998; Müller et al., 2001]. To investigate the current role of the PFS in accommodating Adriatic indentation, we tried to quantify deformation along the PFS over a time span longer than that accessible through seismic or GPS data, but shorter than that constrained by Rb-Sr or Ar-Ar geochronology. For this purpose, we analysed the geomorphology along the PFS in the Eastern Alps, using surface markers to identify possible offsets (e.g., alluvial fans, river terraces or thalwegs). First analyses of aerial photos and river networks combined with DEMs reveal a clear influence of the PFS on the morphology and on drainage network. For example, river channels along the Gailtal fault have apparent dextral offsets of up to 4 km

  11. Fault-tolerant clock synchronization validation methodology. [in computer systems

    Science.gov (United States)

    Butler, Ricky W.; Palumbo, Daniel L.; Johnson, Sally C.

    1987-01-01

    A validation method for the synchronization subsystem of a fault-tolerant computer system is presented. The high reliability requirement of flight-crucial systems precludes the use of most traditional validation methods. The method presented utilizes formal design proof to uncover design and coding errors and experimentation to validate the assumptions of the design proof. The experimental method is described and illustrated by validating the clock synchronization system of the Software Implemented Fault Tolerance computer. The design proof of the algorithm includes a theorem that defines the maximum skew between any two nonfaulty clocks in the system in terms of specific system parameters. Most of these parameters are deterministic. One crucial parameter is the upper bound on the clock read error, which is stochastic. The probability that this upper bound is exceeded is calculated from data obtained by the measurement of system parameters. This probability is then included in a detailed reliability analysis of the system.

  12. Nondestructive detection system of faults in fuses using radioisotope

    International Nuclear Information System (INIS)

    A system is developed to show the viability of non-destructive detection of the faults of explosive safety fuses which are manufactured by Fabrica da Estrela do Ministerio do Exercito. The faults are detected by an ion-chamber based on the variation of the intensity of the beta particles that penetrate the fuse which passes through a collimator. The beta particles are emitted by Strontium-90 + Yttrium-90 encapsulated in either stainless steel or aluminum. The concept of 'bucking Voltage' is applied to differentiate electronically the signal generated by the ion-chamber. (author)

  13. Fault-tolerant design of picture archiving and communication systems

    International Nuclear Information System (INIS)

    Reliability is perhaps the most important attribute of a PACS. Any downtime of the system may seriously affect patient care. This paper describes fault-tolerant measures employed in the design of a hospital-wide PACS. Six fault-tolerant measures have been implemented: hardware redundance (networks and archives), data-base backups, monitoring routines for local host processes and network status; uninterruptible power supplied, structured software design techniques, and in-service training of all radiology technologists. A PACS consisting of 13 acquisition nodes, two optical archiving nodes, two data-base server nodes, and five workstation nodes has been developed

  14. Wiring systems and fault finding for installation electricians

    CERN Document Server

    Scaddan, Brian

    2012-01-01

    This book deals with an area of practice that many students and non-electricians find particularly challenging. It explains how to interpret circuit diagrams, wiring systems, and outlines the principles of testing before explaining how to apply this knowledge to fault finding in electrical circuits. A handy pocket guide for anybody that needs to be able to trace faults in circuits, whether in domestic, commercial or industrial settings, this book will be extremely useful to electricians, plumbers, heating engineers and intruder alarm installers.

  15. Coupling Markov and fault tree techniques for calculating system reliability

    International Nuclear Information System (INIS)

    The fault-tree technique needs Markov for knowing wether or not it itself is applicable for the sake of system-reliability-estimation. The Markov approach can be used for calculating the min-cut-reliabilities (availabilities) when for the latter accurate-enough, handy estimates are not available. (DG)

  16. Fault-Tolerant Control using Adaptive Time-Frequency Method in Bearing Fault Detection for DFIG Wind Energy System

    Directory of Open Access Journals (Sweden)

    Suratsavadee Koonlaboon KORKUA

    2015-02-01

    Full Text Available With the advances in power electronic technology, doubly-fed induction generators (DFIG have increasingly drawn the interest of the wind turbine industry. To ensure the reliable operation and power quality of wind power systems, the fault-tolerant control for DFIG is studied in this paper. The fault-tolerant controller is designed to maintain an acceptable level of performance during bearing fault conditions. Based on measured motor current data, an adaptive statistical time-frequency method is then used to detect the fault occurrence in the system; the controller then compensates for faulty conditions. The feature vectors, including frequency components located in the neighborhood of the characteristic fault frequencies, are first extracted and then used to estimate the next sampling stator side current, in order to better perform the current control. Early fault detection, isolation and successful reconfiguration would be very beneficial in a wind energy conversion system. The feasibility of this fault-tolerant controller has been proven by means of mathematical modeling and digital simulation based on Matlab/Simulink. The simulation results of the generator output show the effectiveness of the proposed fault-tolerant controller.

  17. Development and Evaluation of Fault-Tolerant Flight Control Systems

    Science.gov (United States)

    Song, Yong D.; Gupta, Kajal (Technical Monitor)

    2004-01-01

    The research is concerned with developing a new approach to enhancing fault tolerance of flight control systems. The original motivation for fault-tolerant control comes from the need for safe operation of control elements (e.g. actuators) in the event of hardware failures in high reliability systems. One such example is modem space vehicle subjected to actuator/sensor impairments. A major task in flight control is to revise the control policy to balance impairment detectability and to achieve sufficient robustness. This involves careful selection of types and parameters of the controllers and the impairment detecting filters used. It also involves a decision, upon the identification of some failures, on whether and how a control reconfiguration should take place in order to maintain a certain system performance level. In this project new flight dynamic model under uncertain flight conditions is considered, in which the effects of both ramp and jump faults are reflected. Stabilization algorithms based on neural network and adaptive method are derived. The control algorithms are shown to be effective in dealing with uncertain dynamics due to external disturbances and unpredictable faults. The overall strategy is easy to set up and the computation involved is much less as compared with other strategies. Computer simulation software is developed. A serious of simulation studies have been conducted with varying flight conditions.

  18. [Andreas Vesalius and surgery].

    Science.gov (United States)

    Van Hee, R

    1993-01-01

    By publishing De Humani Corporis Fabrica Libri Septem in 1543, Andries van Wesel (1514-1564) gave surgical science an immense impulse. The revolutionary renovation in the knowledge of man's anatomical structure changed slowly and progressively into topographical and physiological understanding of surgical diseases. At the same time, this made better aimed and more secure operations possible. Apart from the importance of this anatomical publication, Andreas Vesalius also won his spurs as a surgeon. He taught surgery in Padua for many years. He was appointed court physician and surgeon at the Habsburg Court of Charles V and Philip II. He personally performed lots of operations known at the time as major ones. He not only quickly adopted the surgical innovations of his fellow-surgeon Ambroise Paré, but he even performed operations that had been forgotten during several centuries, among which thoracocentesis for pleural empyema. His clinical perspicacity in discovering the indication for some operations was staggering and was appreciated by all great monarchs of Europe in the 16th century. In his several consilia, numerous pieces of advice were given for the treatment of surgical patients. The surgical practice which Vesalius had in Brussels for many years, consequently became most successful. Many publications by Vesalius about surgery and blood-letting are well-known. His Chirurgia magna in septem Libros digesta still remains controversial; these books were published by Prospero Borgarruccio (1560) in 1568 by the Venetian editor Valgrisi. This book gives an excellent survey of surgical pathology as it was taught and treated in the 16th century. The scientific method that Vesalius used, not only in his anatomical studies but also in his surgical practice, deserves not only our full appraisal but should still be studied in our own time. PMID:8209577

  19. Fault Diagnosis for Actuators in a Class of Nonlinear Systems Based on an Adaptive Fault Detection Observer

    Directory of Open Access Journals (Sweden)

    Runxia Guo

    2016-01-01

    Full Text Available The problem of actuators’ fault diagnosis is pursued for a class of nonlinear control systems that are affected by bounded measurement noise and external disturbances. A novel fault diagnosis algorithm has been proposed by combining the idea of adaptive control theory and the approach of fault detection observer. The asymptotical stability of the fault detection observer is guaranteed by setting the adaptive adjusting law of the unknown fault vector. A theoretically rigorous proof of asymptotical stability has been given. Under the condition that random measurement noise generated by the sensors of control systems and external disturbances exist simultaneously, the designed fault diagnosis algorithm is able to successfully give specific estimated values of state variables and failures rather than just giving a simple fault warning. Moreover, the proposed algorithm is very simple and concise and is easy to be applied to practical engineering. Numerical experiments are carried out to evaluate the performance of the fault diagnosis algorithm. Experimental results show that the proposed diagnostic strategy has a satisfactory estimation effect.

  20. Scaling, kinematics and evolution of a polymodal fault system: Hail Creek Mine, NE Australia

    Science.gov (United States)

    Carvell, Jacob; Blenkinsop, Thomas; Clarke, Gavin; Tonelli, Maurizio

    2014-09-01

    We analyse a system of normal faults that cuts sandstone, siltstone, mudstone, coal, and tuff at Hail Creek Coal Mine in the Bowen Basin, NE Australia. Our detailed mapping utilised the dense borehole network and strip mining operations. The fault surfaces have complex geometries, yet the components of the individual faults show similar orientation variability to the whole fault system. The faults and their components dip to the SE, NW, NNW, and SSE with an orthorhombic symmetry that we refer to as polymodal. There are multiple displacement peaks, with complementary changes on adjacent faults. This observation suggests kinematic coherence between neighbouring faults. Twin displacement peaks on some faults suggest that segment linkage occurred on a scale of hundreds of m. These polymodal faults follow the same displacement-length scaling laws as other normal faults. Fault dip is affected by lithology, with steeper dips in more competent (sandstone) beds. An ‘odd-axis’ construction using whole fault planes suggests that they formed in a triaxial strain state (three different principal strains) with vertical shortening, and horizontal extension along principal directions of 148° and 058°. Odd-axis constructions using individual fault components, as opposed to whole faults, give similar principal strain orientations and maximum strain ratios. The variable component orientations, and the consistency of fault kinematics on different scales, suggest that the faults evolved by the propagation or linkage of smaller components with variable orientations, within the same bulk strain state.

  1. Reconfigurable Control of Input Affine Nonlinear Systems under Actuator Fault

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Galeazzi, Roberto

    2015-01-01

    This paper proposes a fault tolerant control method for input-affine nonlinear systems using a nonlinear reconfiguration block (RB). The basic idea of the method is to insert the RB between the plant and the nominal controller such that fault tolerance is achieved without re-designing the nominal...... controller. The role of the RB is twofold: on one hand it transforms the output of the faulty system such that its behaviour is similar to that of the nominal one from the controller’s viewpoint; on the other hand it modifies the control input to the faulty system such that the stability of the reconfigured...... need any knowledge of the nominal controller and only assumes that the nominal closed-loop system is ISS. The method is demonstrated on a dynamic positioning system for an offshore supply vessel, where the virtual actuator is designed using backstepping....

  2. Reliable, fault tolerant control systems for nuclear generating stations

    International Nuclear Information System (INIS)

    Two operational features of CANDU Nuclear Power Stations provide for high plant availability. First, the plant re-fuels on-line, thereby eliminating the need for periodic and lengthy refuelling 'outages'. Second, the all plants are controlled by real-time computer systems. Later plants are also protected using real-time computer systems. In the past twenty years, the control systems now operating in 21 plants have achieved an availability of 99.8%, making significant contributions to high CANDU plant capacity factors. This paper describes some of the features that ensure the high degree of system fault tolerance and hence high plant availability. The emphasis will be placed on the fault tolerant features of the computer systems included in the latest reactor design - the CANDU 3 (450MWe). (author)

  3. Development and application of diagnostic systems to achieve fault tolerance

    International Nuclear Information System (INIS)

    Much work is currently being done to develop and apply diagnostic systems that are tolerant to faulted conditions in the process being monitored and in the sensors that measure the critical parameters associated with the process. A fault-tolerant diagnostic system based on state-determination, pattern-recognition techniques is currently undergoing testing and evaluation in certain applications at the EBR-II reactor. Testing and operational experience with the system to date has shown a high degree of tolerance to sensor failures, while being sensitive to very slight changes in the plant operational state. This paper briefly mentions related work being done by others, and describes in more detail the pattern-recognition system and the results of the testing and operational experience with the system at EBR-II. 9 refs., 10 figs

  4. Application of multi-sensor information fusion technology on fault diagnosis of hydraulic system

    International Nuclear Information System (INIS)

    The structural layers and methods of multi-sensor information fusion technology are analysed, and its application in fault diagnosis of hydraulic system is discussed. Aiming at hydraulic system, a model of hydraulic fault diagnosis system based on multi-sensor information fusion technology is presented. Choosing and implementing the method of information fusion reasonably, the model can fuse and calculate various fault characteristic parameters in hydraulic system effectively and provide more valuable result for fault diagnosis of hydraulic system.

  5. Measurements of soil gas radon in active fault systems: A case study along the North and East anatolian fault systems in Turkey

    International Nuclear Information System (INIS)

    We have used solid-state nuclear track detectors (CR-39) in order to determine the profile of the soil radon in district areas of the North and East Anatolian active fault systems in Turkey. It has been shown that the radon anomalies among the fault zones are relatively high in the fault line while dramatically decreases by going away from the lines. Radon concentrations in both active fault systems ranged from 4.3 to 9.8kBqm-3. The average radon concentration levels in the North Anatolian Fault System are relatively higher than the East Anatolian Fault System. Radon measurement technique is proved to be a good tool for detection and mapping of the active fault zone, and also in the case of continuous monitoring of radon anomalies connected with earthquake events

  6. Calculation of critical fault recovery time for nonlinear systems based on region of attraction analysis

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Blanke, Mogens

    2014-01-01

    of a system. It must be guaranteed that the trajectory of a system subject to fault remains in the region of attraction (ROA) of the post-fault system during this time. This paper proposes a new algorithm to compute the critical fault recovery time for nonlinear systems with polynomial vector elds using sum...

  7. Structural Design of Systems with Safe Behavior under Single and Multiple Faults

    DEFF Research Database (Denmark)

    Blanke, Mogens; Staroswiecki, Marcel

    Handling of multiple simultaneous faults is a complex issue in fault-tolerant control. The design task is particularly made difficult by to the numerous different cases that need be analyzed. Aiming at safe fault-handling, this paper shows how structural analysis can be applied to find the...... structural analysis to disclose which faults could be isolated from a structural point of view using active fault isolation. Results from application on a marine control system illustrate the concepts....

  8. Methods for Fault Diagnosability Analysis of a Class of Affine Nonlinear Systems

    Directory of Open Access Journals (Sweden)

    Xiafu Peng

    2015-01-01

    Full Text Available The fault diagnosability analysis for a given model, before developing a diagnosis algorithm, can be used to answer questions like “can the fault fi be detected by observed states?” and “can it separate fault fi from fault fj by observed states?” If not, we should redesign the sensor placement. This paper deals with the problem of the evaluation of detectability and separability for the diagnosability analysis of affine nonlinear system. First, we used differential geometry theory to analyze the nonlinear system and proposed new detectability criterion and separability criterion. Second, the related matrix between the faults and outputs of the system and the fault separable matrix are designed for quantitative fault diagnosability calculation and fault separability calculation, respectively. Finally, we illustrate our approach to exemplify how to analyze diagnosability by a certain nonlinear system example, and the experiment results indicate the effectiveness of the fault evaluation methods.

  9. Systems analysis approach to probabilistic modeling of fault trees

    International Nuclear Information System (INIS)

    A method of probabilistic modeling of fault tree logic combined with stochastic process theory (Markov modeling) has been developed. Systems are then quantitatively analyzed probabilistically in terms of their failure mechanisms including common cause/common mode effects and time dependent failure and/or repair rate effects that include synergistic and propagational mechanisms. The modeling procedure results in a state vector set of first order, linear, inhomogeneous, differential equations describing the time dependent probabilities of failure described by the fault tree. The solutions of this Failure Mode State Variable (FMSV) model are cumulative probability distribution functions of the system. A method of appropriate synthesis of subsystems to form larger systems is developed and applied to practical nuclear power safety systems

  10. Reliability modeling of digital component in plant protection system with various fault-tolerant techniques

    International Nuclear Information System (INIS)

    Highlights: • Integrated fault coverage is introduced for reflecting characteristics of fault-tolerant techniques in the reliability model of digital protection system in NPPs. • The integrated fault coverage considers the process of fault-tolerant techniques from detection to fail-safe generation process. • With integrated fault coverage, the unavailability of repairable component of DPS can be estimated. • The new developed reliability model can reveal the effects of fault-tolerant techniques explicitly for risk analysis. • The reliability model makes it possible to confirm changes of unavailability according to variation of diverse factors. - Abstract: With the improvement of digital technologies, digital protection system (DPS) has more multiple sophisticated fault-tolerant techniques (FTTs), in order to increase fault detection and to help the system safely perform the required functions in spite of the possible presence of faults. Fault detection coverage is vital factor of FTT in reliability. However, the fault detection coverage is insufficient to reflect the effects of various FTTs in reliability model. To reflect characteristics of FTTs in the reliability model, integrated fault coverage is introduced. The integrated fault coverage considers the process of FTT from detection to fail-safe generation process. A model has been developed to estimate the unavailability of repairable component of DPS using the integrated fault coverage. The new developed model can quantify unavailability according to a diversity of conditions. Sensitivity studies are performed to ascertain important variables which affect the integrated fault coverage and unavailability

  11. Reliability modeling of digital component in plant protection system with various fault-tolerant techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bo Gyung, E-mail: bogyungkim@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kang, Hyun Gook [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Department of Nuclear Engineering, Khalifa University of Science, Technology and Research, Abu Dhabi (United Arab Emirates); Kim, Hee Eun [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Lee, Seung Jun [Integrated Safety Assessment Team, Korea Atomic Energy Research Institute, 1045, Daedeok-daero, Daejeon 305-353 (Korea, Republic of); Seong, Poong Hyun [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2013-12-15

    Highlights: • Integrated fault coverage is introduced for reflecting characteristics of fault-tolerant techniques in the reliability model of digital protection system in NPPs. • The integrated fault coverage considers the process of fault-tolerant techniques from detection to fail-safe generation process. • With integrated fault coverage, the unavailability of repairable component of DPS can be estimated. • The new developed reliability model can reveal the effects of fault-tolerant techniques explicitly for risk analysis. • The reliability model makes it possible to confirm changes of unavailability according to variation of diverse factors. - Abstract: With the improvement of digital technologies, digital protection system (DPS) has more multiple sophisticated fault-tolerant techniques (FTTs), in order to increase fault detection and to help the system safely perform the required functions in spite of the possible presence of faults. Fault detection coverage is vital factor of FTT in reliability. However, the fault detection coverage is insufficient to reflect the effects of various FTTs in reliability model. To reflect characteristics of FTTs in the reliability model, integrated fault coverage is introduced. The integrated fault coverage considers the process of FTT from detection to fail-safe generation process. A model has been developed to estimate the unavailability of repairable component of DPS using the integrated fault coverage. The new developed model can quantify unavailability according to a diversity of conditions. Sensitivity studies are performed to ascertain important variables which affect the integrated fault coverage and unavailability.

  12. Estimation and fault diagnosis strategies for networked control systems

    OpenAIRE

    Dolz Algaba, Daniel

    2014-01-01

    Communication networks increase flexibility of industrial monitoring, supervisory and control systems. However, they introduce delays or even dropouts on the transmitted information that affect the performance and robustness on the decision and control mechanisms in the system. This thesis contributes theoretically to the state estimation and fault diagnosis problem over networks. First, we study the state estimation problem. Motivated by reducing the implementation computational load of L...

  13. Testing Virtual Reconfigurable Circuit Designed For A Fault Tolerant System

    OpenAIRE

    P. N. Kumar; S. Anandhi; M. Elancheralathan; J. R.P. Perinbam

    2007-01-01

    This research describes about the testing of virtual reconfigurable circuit (VRC) designed and implemented for a fault tolerant system which averages the (three) sensor inputs. The circuits that are to be tested are those which are successfully evolved in this system under different situations such as (i) all the three sensors are faultless (ii) one of the input sensor fails as open (iii) sensors fails as short circuit. The objective of this research is to test the desired optimal circuits ev...

  14. Fault current analysis in JT-60 grounding system

    International Nuclear Information System (INIS)

    The determination of a ground fault current is described in the case where a ground fault occurs in JT-60 device. Specifically, a case in which six coils caused a simultaneous ground fault is investigated. It is found that when faults in vertical and toroidal magnetic field coils occur simultaneously, the resultant ground fault current is very large

  15. Probabilistic Fault Diagnosis in Electrical Power Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — Electrical power systems play a critical role in spacecraft and aircraft. This paper discusses our development of a diagnostic capability for an electrical power...

  16. Andreas Struppleri intelligentsed rakendused / Andreas Struppler ; interv. Margit Aedla

    Index Scriptorium Estoniae

    Struppler, Andreas

    2008-01-01

    Disainer Andreas Struppler (sünd. 1964) enda ja oma meeskonna loodud e-mood'i sarja vannitoast, valgustusest vannitoas. Privaatala eraldamiseks ülejäänud vannitoast suunatakse värviline valgus keraamiliselt trükitud klaaspaneelile. E-sirm on ruumijagaja moodne tõlgendus

  17. Advanced monitoring, fault diagnostics, and maintenance of cryogenic systems

    CERN Document Server

    Girone, Mario; Pezzetti, Marco

    In this Thesis, advanced methods and techniques of monitoring, fault diagnostics, and predictive maintenance for cryogenic processes and systems are described. In particular, in Chapter 1, mainstreams in research on measurement systems for cryogenic processes are reviewed with the aim of dening key current trends and possible future evolutions. Then, in Chapter 2, several innovative methods are proposed. A transducer based on a virtual ow meter is presented for monitoring helium distribution and consumption in cryogenic systems for particle accelerators [1]. Furthermore, a comprehensive metrological analysis of the proposed transducer for verifying the metrological performance and pointing out most critical uncertainty sources is described [2]. A model-based method for fault detection and early-stage isolation, able to work with few records of Frequency Response Function (FRF) on an unfaulty compressor, is then proposed [3]. To enrich the proposal, a distributed diagnostic procedure, based on a micro-genetic...

  18. Fault recovery for real-time, multi-tasking computer system

    Science.gov (United States)

    Hess, Richard (Inventor); Kelly, Gerald B. (Inventor); Rogers, Randy (Inventor); Stange, Kent A. (Inventor)

    2011-01-01

    System and methods for providing a recoverable real time multi-tasking computer system are disclosed. In one embodiment, a system comprises a real time computing environment, wherein the real time computing environment is adapted to execute one or more applications and wherein each application is time and space partitioned. The system further comprises a fault detection system adapted to detect one or more faults affecting the real time computing environment and a fault recovery system, wherein upon the detection of a fault the fault recovery system is adapted to restore a backup set of state variables.

  19. Automatic fault detection on BIPV systems without solar irradiation data

    CERN Document Server

    Leloux, Jonathan; Luna, Alberto; Desportes, Adrien

    2014-01-01

    BIPV systems are small PV generation units spread out over the territory, and whose characteristics are very diverse. This makes difficult a cost-effective procedure for monitoring, fault detection, performance analyses, operation and maintenance. As a result, many problems affecting BIPV systems go undetected. In order to carry out effective automatic fault detection procedures, we need a performance indicator that is reliable and that can be applied on many PV systems at a very low cost. The existing approaches for analyzing the performance of PV systems are often based on the Performance Ratio (PR), whose accuracy depends on good solar irradiation data, which in turn can be very difficult to obtain or cost-prohibitive for the BIPV owner. We present an alternative fault detection procedure based on a performance indicator that can be constructed on the sole basis of the energy production data measured at the BIPV systems. This procedure does not require the input of operating conditions data, such as solar ...

  20. A Fault-tolerant Development Methodology for Industrial Control Systems

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Thybo, C.

    2004-01-01

    Developing advanced detection schemes is not the lone factor for obtaining a successful fault diagnosis performance. Acquiring significant achievements in applying Fault-tolerance in industrial development requires that fault diagnosis and recovery schemes are developed in a consistent and...

  1. Investigating multiple fault rupture at the Salar del Carmen segment of the Atacama Fault System (northern Chile): Fault scarp morphology and knickpoint analysis

    Science.gov (United States)

    Ewiak, Oktawian; Victor, Pia; Oncken, Onno

    2015-02-01

    This study presents a new geomorphological approach to investigate the past activity and potential seismic hazard of upper crustal faults at the Salar del Carmen segment of the Atacama Fault System in the northern Chile forearc. Our contribution is based on the analysis of a large set of topographic profiles and allows extrapolating fault analysis from a few selected locations to distances of kilometers along strike of the fault. We detected subtle changes in the fault scarp geometry which may represent the number of paleoearthquakes experienced by the structure and extracted the cumulative and last incremental displacement along strike of the investigated scarps. We also tested the potential of knickpoints in channels crossing the fault scarps as markers for repeated fault rupture and proxies for seismic displacement. The number of paleoearthquakes derived from our analysis is 2-3, well in agreement with recent paleoseismological investigations, which suggest 2-3 earthquakes (Mw = 6.5-6.7) at the studied segments. Knickpoints record the number of events for about 55% of the analyzed profile pairs. Only few knickpoints represent the full seismic displacement, while most retain only a fraction of the displacement. The along-strike displacement distributions suggest fault growth from the center toward the tips and linkage of individual ruptures. Our approach also improves the estimation of paleomagnitudes in case of multiple fault rupture by allowing to quantify the last increment of displacement separately. Paleomagnitudes calculated from total segment length and the last increment of displacement (Mw = 6.5-7.1) are in agreement with paleoseismological results.

  2. Design and implementation of an expert system for remote fault diagnosis in ship lift

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper an expert system for remote fault diagnosis in the ship lift was developed by analysis of the fault tree and combination with VPN. The fault tree was constructed based on the operation condition of the ship lift. The diagnosis model was constructed by hierarchical classification of the fault tree structure, and the inference mechanism was given. Logical structure of the fault diagnosis in the ship lift was proposed. The implementation of the expert system for remote fault diagnosis in the ship...

  3. ANDREAE VESALII: THE BONES AND MUSCLES ANDREA VESALII: LOS HUESOS Y LOS MÚSCULOS

    OpenAIRE

    Henrique Ayres de Vasconcellos; Pedro Henrique Barros de Vasconcellos

    2004-01-01

    The historical references are taken from Aristoteles (384-322 a C) considered the father of Kinesiology, and Claudius Galenus from Pergamon (131-201), the first team doctor. Both men´s studies shared the same objective: functional-anatomic aspects related to the Locomotive System. Although there were several descriptive anatomic studies of bones and muscles, it was Andreas Vesalius (1514-1564), whom most significantly contributed to the development of a new methodology for the lectures ...

  4. Hidden Markov models for fault detection in dynamic systems

    Science.gov (United States)

    Smyth, Padhraic J. (Inventor)

    1995-01-01

    The invention is a system failure monitoring method and apparatus which learns the symptom-fault mapping directly from training data. The invention first estimates the state of the system at discrete intervals in time. A feature vector x of dimension k is estimated from sets of successive windows of sensor data. A pattern recognition component then models the instantaneous estimate of the posterior class probability given the features, p(w(sub i) (vertical bar)/x), 1 less than or equal to i isless than or equal to m. Finally, a hidden Markov model is used to take advantage of temporal context and estimate class probabilities conditioned on recent past history. In this hierarchical pattern of information flow, the time series data is transformed and mapped into a categorical representation (the fault classes) and integrated over time to enable robust decision-making.

  5. Diagnostic software and fault tolerant microprocessor based system architectures

    International Nuclear Information System (INIS)

    In numerous industrial applications including power generation, the availability of electronic systems to perform the tasks assigned has become a major issue. At the same time, the functional complexity of these systems has increased enormously. Fortunately, the arrival of cost effective microprocessor based hardware has given the system designer a cadre of techniques to ensure the desired degree of system integrity and availability. These include: dynamic redundancy, isolation, functional diversity, built-in self-tests, embedded test subsystems, communications, error checking and error correcting codes, etc. The choice among the available techniques is generally heuristic and depends greatly on the structure of major components and systems external to the electronic system itself as well as the postulated faults and their relative frequency. Indiscriminate use of these techniques will inevitably increase cost and reduce maintainability while actually reducing system availability and reliability. The issues and the application of these techniques are discussed by describing recent examples of fault tolerant microprocessor based system architectures which include the Plant Safety Monitoring System, the EAGLE-21 Process Protection System and the Advanced Rod Position Indication System for pressurized water reactors. Each of these systems utilize unique internal architectures that address the reliability, availability, and the communications issues while improving maintainability and man-machine interfaces

  6. Pärnograafiline / Andreas Trossek

    Index Scriptorium Estoniae

    Trossek, Andreas, 1980-

    2007-01-01

    Priit Pärna näitus Kumu Kunstimuuseumis kuni 21. X. Kuraator Eha Komissarov. 11. V toimus Kumu auditooriumis Priit Pärna loomingule pühendatud rahvusvaheline seminar, peaesinejaks oli Edwin Carels Belgiast. Esitamisele tuli filmiprogramm Priit Pärna filmidest ning toimus ümarlaud, milles osalesid Andreas Trossek, Mari Laaniste ja Priit Pärn

  7. Performance-Oriented Fault Tolerance in Computing Systems

    OpenAIRE

    Borodin, D

    2010-01-01

    In this dissertation we address the overhead reduction of fault tolerance (FT) techniques. Due to technology trends such as decreasing feature sizes and lowering voltage levels, FT is becoming increasingly important in modern computing systems. FT techniques are based on some form of redundancy. It can be space redundancy (additional hardware), time redundancy (multiple executions), and/or information redundancy (additional verification information). This redundancy significantly increases th...

  8. Fault detection in mechanical systems based on subspace features

    OpenAIRE

    Nguyen, Viet Ha; Rutten, Christophe; Golinval, Jean-Claude

    2010-01-01

    In the field of structural health monitoring or machine condition monitoring, the activation of nonlinear dynamic behavior complicates the procedure of damage or fault detection. Principal Component Analysis (PCA) is known as an efficient method for damage diagnosis. However, two drawbacks of PCA are the assumption of the linearity of the system and the need of many sensors. This article presents industrial applications of two possible extensions of PCA: Null subspace analysis (NSA) and Kerne...

  9. Logic-dynamic approach to fault diagnosis in mechatronic systems

    Directory of Open Access Journals (Sweden)

    A. N. Zhirabok

    2008-11-01

    Full Text Available This paper presents a problem of fault detection and isolation (FDI in mechatronic systems described by nonlinear dynamic models with such types of no differentiable nonlinearities as saturation, Coulomb friction, backlash, and hysteresis. To solve this problem, so-called logic-dynamic approach is suggested. This approach consists of three main steps: replacing the initial nonlinear system by certain linear logic-dynamic system, obtaining the bank of linear logic-dynamic observers, and transforming these observes into the nonlinear ones. Logic-dynamic approach allows one to use the linear FDI methods for diagnosis in nonlinear mechatronic systems.

  10. An Intelligent Fault Diagnosis System for Machine Tools

    Directory of Open Access Journals (Sweden)

    Chia Wang

    2014-08-01

    Full Text Available An automatic intelligent system is developed to diagnose shaft fault types. Features related to shaft faults are extracted from vibration signals to effectively identify the corresponding fault condition. Feature extraction is accomplished using Fourier Transform, empirical mode decomposition (EMD and multi-scale entropy (MSE. Through the EMD method, the model uses characteristics of intrinsic mode functions (such as zero-crossing rate and energy, to represent shaft condition features. MSE is used to calculate the entropy of multi-scale of the signal. At a larger MSE scale, the MSE result can be used to clearly identify some shaft defect types. The conventional approach to monitoring of a machine’s health online based on linear time-frequency analysis is subject to limitations, as the mechanical vibration signal is nonlinear and non-stationary in nature. Thus this research develops a diagnostic system based on the implementation of Fourier, EMD and MSE-based methods. In the buildup stage a knowledgeware is created from a database of existing defect types. Finally, the automatic intelligent monitoring system is implemented in a machine tool manufacturing company to verify its performance.

  11. Automatic learning of state machines for fault detection systems in discrete event based distributed systems

    OpenAIRE

    Neuner, Oliver

    2011-01-01

    The electronic components in modern automobiles build up a distributed system with so called electronic control units connected via bus systems. As more safety- and security-relevant functions are implemented in such systems, the more important fault detection becomes. A promising approach to fault detection is to build a system model from state machines and compare its predictions with properties observed in a real system. In the automobile, potential are communication characteristics betwee...

  12. Doubly fed induction generator based wind turbine systems subject to recurring grid faults

    DEFF Research Database (Denmark)

    Chen, Wenjie; Blaabjerg, Frede; Zhu, Nan; Chen, Min; Xu, Dehong

    New grid codes demand the wind turbine systems to ride through recurring grid faults. In this paper, the performance of the Doubly Fed Induction Generator wind turbine system under recurring grid faults is analyzed. The stator natural flux produced by the voltage recovery after the first grid fault...

  13. Design and Assessment of a Multiple Sensor Fault Tolerant Robust Control System

    Directory of Open Access Journals (Sweden)

    J. Chen

    2008-03-01

    Full Text Available This paper presents an enhanced robust control design structure to realise fault tolerance towards sensor faults suitable for multi-input-multi-output (MIMO systems implementation. The proposed design permits fault detection and controller elements to be designed with considerations to stability and robustness towards uncertainties besides multiple faults environment on a common mathematical platform. This framework can also cater to systems requiring fast responses. A design example is illustrated with a fast, multivariable and unstable system, that is, the double inverted pendulum system. Results indicate the potential of this design framework to handle fast systems with multiple sensor faults.

  14. A proposal of surveying and evaluating system of active faults for earthquake assessment

    International Nuclear Information System (INIS)

    1. Paleoseismology of the Itoigawa-Shizuoka Tectonic Line active fault system: We investigated co-seismic faulting activity of the Itoigawa-Shizuoka Tectonic Line active fault system (ISTL) to clarify behavioral segmentation of long and massive faults. Geomorphologic and geologic surveys, trench excavation, and seismic reflection survey in the southern to central parts of ISTL revealed paleoseismologic faulting events occurred in the last thousands years and characteristics of geometric, structural, and geomorphologic segments. Each paleoseismic event, co-seismic displacement of deposit, average slip rate, and recurrence intervals suggest that the latest paleo-earthquake occurred in 1700 cal y BP and involved multiple segments in the Okaya to the Shimotsuburai faults. The estimated surface rupture length for this event is up to 77 km or possibly up to 94 km long. The another latest event occurred after 1200 cal y BP at the Ichinose fault and adjacent active faults. In addition, ca. 1200 cal y BP event at the Gofukuji fault occurred and involved multiple segments in the northern ISTL. Behavioral boundaries of these distinctive paleoseismic events were present in segment boundaries of geometric characters and slip rate variation. In the ISTL, geometric segmentation and slip-rate variation likely coincide with the estimated behavioral segmentation. Therefore, this finding suggests that geometric segment and slip-rate variation play an important role to determine the size of the maximum behavioral segment. 2. Active fault study on the 1999 Taiwan Chichi Earthquake area: The earthquake fault was appeared along the Chelungpu Fault while the 1999 Chichi Earthquake has occurred. The N-S striking fault has been recognized as an active fault, however E-W direction earthquake fault has not been described before the earthquake as an active fault. The later fault appeared just beneath the Shihkang Dam and the dam was destroyed by the fault. This study revealed that the E

  15. Fault Analysis of Space Station DC Power Systems-Using Neural Network Adaptive Wavelets to Detect Faults

    Science.gov (United States)

    Momoh, James A.; Wang, Yanchun; Dolce, James L.

    1997-01-01

    This paper describes the application of neural network adaptive wavelets for fault diagnosis of space station power system. The method combines wavelet transform with neural network by incorporating daughter wavelets into weights. Therefore, the wavelet transform and neural network training procedure become one stage, which avoids the complex computation of wavelet parameters and makes the procedure more straightforward. The simulation results show that the proposed method is very efficient for the identification of fault locations.

  16. Fault Detection and Isolation of Wind Energy Conversion Systems using Recurrent Neural Networks

    OpenAIRE

    N. Talebi; M.A. Sadrnia; A. Darabi

    2014-01-01

    Reliability of Wind Energy Conversion Systems (WECSs) is greatly important regarding to extract the maximum amount of available wind energy. In order to accurately study WECSs during occurrence of faults and to explore the impact of faults on each component of WECSs, a detailed model is required in which mechanical and electrical parts of WECSs are properly involved. In addition, a Fault Detection and Isolation System (FDIS) is required by which occurred faults can be diagnosed at the appropr...

  17. Faults delineation and stress orientations from the microseismicity analysis of the Servita Fault System, Colombian Eastern Cordillera

    Science.gov (United States)

    Pedraza García, P.; Dimate, C.

    2014-12-01

    The Servita Fault System (SFS) is located in the eastern foothills of the Colombian Andes Eastern Cordillera. This region is a structurally complex area with high seismogenic potential. The refined analysis of the microseismicity registered by a portable seismic network allows to delineate the main active faults and to estimate the direction of the regional tectonic stress. We analyzed a high quality microearthquake data-set consisting of 890 events occurred during 2011-2012 with a local magnitude range between 0.1 and 3.2 and depths up to 40km. The refined locations of the events show a general SW-NE trend that follows the trace of the SFS. Selected focal mechanisms show predominantly right-lateral strike slip motion. Results show that seismicity to the northern sector of the SFS is distributed in two groups, one on the axial zone of the cordillera and the other on the eastern flank. Most of the microearthquakes are concentrated in the rupture zone of Quetame earthquake (2008, Mw=5.9). Alignment of hypocenters along the eastern flank and some focal mechanisms suggest a fault plane dipping to the west, which is interpreted as the Servita Fault plane. Southwards of the Rio Negro, seismicity decreases and loses continuity. This feature coincides with the trace of the WSW-ENE Rio Blanco Fault which possibly segments the Servita Fault. Southwards, seismicity is spread over a wider area and exhibits deeper hypocenters compared to the northern sector. Hypocenter distribution and focal mechanisms in this sector suggest two planes dipping to the west which we interpret as segments of the Algeciras Fault and another plane (northwards) steeply dipping to the southeast interpreted as the fault plane of the Altamira Fault.

  18. Development of a Digital Ground Fault Monitoring System for NCSX

    Science.gov (United States)

    Peel, Justin; Schneider, Hans

    2003-10-01

    The National Spherical Torus Experiment (NSTX) at the Princeton Plasma Physics Laboratory (PPPL) currently uses an analog-based lock-in amplifer system to detect ground faults and ground loops. An alternate system using Digital Signal Processing (DSP) was designed and tested for possible use with NSTX and the National Compact Stellerator Experiment (NCSX), which will be built at PPPL in the future. The DSP system uses Finite Impulse Response (FIR) and Moving Average (MA) filters to implement a digital lock-in analyzer on a single DSP board.

  19. Research on the Algorithm of Avionic Device Fault Diagnosis Based on Fuzzy Expert System

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the fuzzy expert system fault diagnosis theory, the knowledge base architecture and inference engine algorithm are put forward for avionic device fault diagnosis. The knowledge base is constructed by fault query network, of which the basic element is the test-diagnosis fault unit. Every underlying fault cause's membership degree is calculated using fuzzy product inference algorithm, and the fault answer best selection algorithm is developed, to which the deep knowledge is applied. Using some examples,the proposed algorithm is analyzed for its capability of synthesis diagnosis and its improvement compared to greater membership degree first principle.

  20. Ship Propulsion System as a Benchmark for Fault-Tolerant Control

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Blanke, M.

    1998-01-01

    -tolerant control is a fairly new area. The paper presents a ship propulsion system as a benchmark that should be useful as a platform for development of new ideas and comparison of methods. The benchmark has two main elements. One is development of efficient FDI algorithms, the other is analysis and implementation......Fault-tolerant control combines fault detection and isolation techniques with supervisory control to achieve autonomous accommodation of faults before they develop into failures. While fault detection and isolation (FDI) methods have matured during the past decade the extension to fault...... of autonomous fault accommodation. A benchmark kit can be obtained from the authors....

  1. Fuzzy Timing Petri Net for Fault Diagnosis in Power System

    Directory of Open Access Journals (Sweden)

    Alireza Tavakholi Ghainani

    2012-01-01

    Full Text Available A model-based system for fault diagnosis in power system is presented in this paper. It is based on fuzzy timing Petri net (FTPN. The ordinary Petri net (PN tool is used to model the protective components, relays, and circuit breakers. In addition, fuzzy timing is associated with places (token/transition to handle the uncertain information of relays and circuits breakers. The received delay time information of relays and breakers is mapped to fuzzy timestamps, π(τ, as initial marking of the backward FTPN. The diagnosis process starts by marking the backward sub-FTPNs. The final marking is found by going through the firing sequence, σ, of each sub-FTPN and updating fuzzy timestamp in each state of σ. The final marking indicates the estimated fault section. This information is then in turn used in forward FTPN to evaluate the fault hypothesis. The FTPN will increase the speed of the inference engine because of the ability of Petri net to describe parallel processing, and the use of time-tag data will cause the inference procedure to be more accurate.

  2. PV Systems Reliability Final Technical Report: Ground Fault Detection

    Energy Technology Data Exchange (ETDEWEB)

    Lavrova, Olga [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Flicker, Jack David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    We have examined ground faults in PhotoVoltaic (PV) arrays and the efficacy of fuse, current detection (RCD), current sense monitoring/relays (CSM), isolation/insulation (Riso) monitoring, and Ground Fault Detection and Isolation (GFID) using simulations based on a Simulation Program with Integrated Circuit Emphasis SPICE ground fault circuit model, experimental ground faults installed on real arrays, and theoretical equations.

  3. A System for Fault Management for NASA's Deep Space Habitat

    Science.gov (United States)

    Colombano, Silvano P.; Spirkovska, Liljana; Aaseng, Gordon B.; Mccann, Robert S.; Baskaran, Vijayakumar; Ossenfort, John P.; Smith, Irene Skupniewicz; Iverson, David L.; Schwabacher, Mark A.

    2013-01-01

    NASA's exploration program envisions the utilization of a Deep Space Habitat (DSH) for human exploration of the space environment in the vicinity of Mars and/or asteroids. Communication latencies with ground control of as long as 20+ minutes make it imperative that DSH operations be highly autonomous, as any telemetry-based detection of a systems problem on Earth could well occur too late to assist the crew with the problem. A DSH-based development program has been initiated to develop and test the automation technologies necessary to support highly autonomous DSH operations. One such technology is a fault management tool to support performance monitoring of vehicle systems operations and to assist with real-time decision making in connection with operational anomalies and failures. Toward that end, we are developing Advanced Caution and Warning System (ACAWS), a tool that combines dynamic and interactive graphical representations of spacecraft systems, systems modeling, automated diagnostic analysis and root cause identification, system and mission impact assessment, and mitigation procedure identification to help spacecraft operators (both flight controllers and crew) understand and respond to anomalies more effectively. In this paper, we describe four major architecture elements of ACAWS: Anomaly Detection, Fault Isolation, System Effects Analysis, and Graphic User Interface (GUI), and how these elements work in concert with each other and with other tools to provide fault management support to both the controllers and crew. We then describe recent evaluations and tests of ACAWS on the DSH testbed. The results of these tests support the feasibility and strength of our approach to failure management automation and enhanced operational autonomy.

  4. Upper crustal fault reactivation and the potential of triggered earthquakes on the Atacama Fault System, N-Chile

    Science.gov (United States)

    Victor, Pia; Ewiak, Oktawian; Thomas, Ziegenhagen; Monika, Sobiesiak; Bernd, Schurr; Gabriel, Gonzalez; Onno, Oncken

    2016-04-01

    The Atacama Fault System (AFS) is an active trench-parallel fault system, located in the forearc of N-Chile directly above the subduction zone interface. Due to its well-exposed position in the hyper arid forearc of N-Chile it is the perfect target to investigate the interaction between the deformation cycle in the overriding forearc and the subduction zone seismic cycle of the underlying megathrust. Although the AFS and large parts of the upper crust are devoid of any noteworthy seismicity, at least three M=7 earthquakes in the past 10 ky have been documented in the paleoseismological record, demonstrating the potential of large events in the future. We apply a two-fold approach to explore fault activation and reactivation patterns through time and to investigate the triggering potential of upper crustal faults. 1) A new methodology using high-resolution topographic data allows us to investigate the number of past earthquakes for any given segment of the fault system as well as the amount of vertical displacement of the last increment. This provides us with a detailed dataset of past earthquake rupture of upper plate faults which is potentially linked to large subduction zone earthquakes. 2) The IPOC Creepmeter array (http://www.ipoc-network.org/index.php/observatory/creepmeter.html) provides us with high-resolution time series of fault displacement accumulation for 11 stations along the 4 most active branches of the AFS. This array monitors the displacement across the fault with 2 samples/min with a resolution of 1μm. Collocated seismometers record the seismicity at two of the creepmeters, whereas the regional seismicity is provided by the IPOC Seismological Networks. Continuous time series of the creepmeter stations since 2009 show that the shallow segments of the fault do not creep permanently. Instead the accumulation of permanent deformation occurs by triggered slip caused by local or remote earthquakes. The 2014 Mw=8.2 Pisagua Earthquake, located close to

  5. Online fault location on crossbonded AC cables in underground transmission systems

    DEFF Research Database (Denmark)

    F. Jensen, Christian; Bak, Claus Leth; Gudmundsdottir, Unnur Stella

    2014-01-01

    of a 245 kV crossbonded cable system, connecting the newly installed 400 MW Danish offshore wind farm Anholt to the main grid, are obtained and used to verify the proposed system. Furthermore, extensive simulation data created in PSCAD/EMTDC is used in order to examine the robustness of the system to......In this paper, a fault locator system specifically designed for crossbonded cables is described. Electromagnetic wave propagation theory for crossbonded cables with focus on fault location purposes is discussed. Based on this, the most optimal modal component and input signal to the fault locator...... system are identified. The fault locator system uses the Wavelet Transform both to create reliable triggers in the units and to estimate the fault location based on time domain signals obtained in the substations by two fault locator units. Field measurements of faults artificially created on a section...

  6. A fault diagnosis system for nuclear power plant operation

    International Nuclear Information System (INIS)

    A fault diagnosis system has been developed to support operators in nuclear power plants. In the system various methods are combined to get a diagnosis result which provides better detection sensitivity and result reliability. The system is composed of an anomaly detection part with diagnosis modules, an integration part which obtains the diagnosis result by combining results from each diagnosis module, and a prediction part with state prediction and estimation modules. For the anomaly detection part, three kinds of modules are prepared: plant signal processing, early fault detection and event identification modules. The plant signal processing module uses wavelet transform and chaos technologies as well as fast Fourier transform (FFT) to analyze vibration sensor signals and to detect signal anomaly. The early fault detection module uses the neural network model of a plant subprocess to estimate the process variable values assuming normal conditions, and to detect an anomaly by comparing the measured and estimated values. The event identification module identifies the kind of occurring event by using the neural network and knowledge processing. In the integration part the diagnosis is performed by using knowledge processing. The knowledge for diagnosis is structured based on the means-ends abstraction hierarchy to simplify knowledge input and maintenance. In the prediction part, the prediction module predicts the future changes of process variables and plant interlock statuses and the estimation module estimates the values of unmeasurable variables. A prototype system has been developed and the system performance was evaluated. The evaluation results show that the developed technologies are effective to improve the human-machine system for plant operation. (author)

  7. Field Guide for Testing Existing Photovoltaic Systems for Ground Faults and Installing Equipment to Mitigate Fire Hazards

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, William [Brooks Engineering, Vacaville, CA (United States); Basso, Thomas [National Renewable Energy Lab. (NREL), Golden, CO (United States); Coddington, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-01

    Ground faults and arc faults are the two most common reasons for fires in photovoltaic (PV) arrays and methods exist that can mitigate the hazards. This report provides field procedures for testing PV arrays for ground faults, and for implementing high resolution ground fault and arc fault detectors in existing and new PV system designs.

  8. Fault Tolerant Software: a Multi Agent System Solution

    DEFF Research Database (Denmark)

    Caponetti, Fabio; Bergantino, Nicola; Longhi, Sauro

    2009-01-01

    Development of high dependable systems remains a labour intensive task. This paper explores recent advances on the adaptation of the software agent architecture for control application while looking to dependability issues. Multiple agent systems theory will be reviewed giving methods to supervise...... it. Software ageing is shown to be the most common problem and rejuvenation its counteract. The paper will show how an agent population can be monitored, faulty agents isolated and reloaded in a healthy state, hence rejuvenated. The aim is to propose an architecture as basis for the design of control...... software able to tolerate faults and residual bugs without the need of maintenance stops....

  9. Wavelet Based Fault Detection, Classification in Transmission System with TCSC Controllers

    Directory of Open Access Journals (Sweden)

    G.Satyanarayana,

    2015-08-01

    Full Text Available This paper presents simulation results of the application of distance relays for the protection of transmission systems employing flexible alternating current transmission controllers such as Thyristor Controlled Series Capacitor (TCSC. The complete digital simulation of TCSC within a transmission system is performed in the MATLAB/Simulink environment using the Power System Block set (PSB. This paper presents an efficient method based on wavelet transforms both fault detection and classification which is almost independent of fault impedance, fault location and fault inception angle of transmission line fault currents with FACTS controllers.

  10. Actuator fault estimation and accommodation for switched systems with time delay: Discrete-time case.

    Science.gov (United States)

    Du, Dongsheng; Jiang, Bin

    2016-05-01

    This paper investigates the problems of actuator fault estimation and accommodation for discrete-time switched systems with state delay. By using reduced-order observer method and switched Lyapunov function technique, a fault estimation algorithm is achieved for the discrete-time switched system with actuator fault and state delay. Then based on the obtained online fault estimation information, a switched dynamic output feedback controller is employed to compensate for the effect of faults by stabilizing the closed-loop systems. Finally, an example is proposed to illustrate the obtained results. PMID:26924247

  11. Method for detecting an open-switch fault in a grid-connected NPC inverter system

    DEFF Research Database (Denmark)

    Choi, Ui-Min; Jeong, Hae-Gwang; Lee, Kyo-Beum; Blaabjerg, Frede

    2012-01-01

    This paper proposes a fault-detection method for an open-switch fault in the switches of grid-connected neutral-point-clamped inverter systems. The proposed method can not only detect the fault condition but also identify the location of the faulty switch. In the proposed method, which is designe...

  12. Fault Detection and Isolation for a Supermarket Refrigeration System - Part One

    DEFF Research Database (Denmark)

    Yang, Zhenyu; Rasmussen, Karsten B.; Kieu, Anh T.;

    2011-01-01

    Fault Detection and Isolation (FDI) using the Kalman Filter (KF) technique for a supermarket refrigeration system is explored. Four types of sensor fault scenarios, namely drift, offset, freeze and hard-over, are considered for two temperature sensors, and one type of parametric fault scenario...

  13. Analytical Model-based Fault Detection and Isolation in Control Systems

    DEFF Research Database (Denmark)

    Vukic, Z.; Ozbolt, H.; Blanke, M.

    1998-01-01

    The paper gives an introduction and an overview of the field of fault detection and isolation for control systems. The summary of analytical (quantitative model-based) methodds and their implementation are presented. The focus is given to mthe analytical model-based fault-detection and fault...

  14. Towards fault-tolerant decision support systems for ship operator guidance

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam; Lajic, Zoran; Jensen, Jørgen Juncher

    2012-01-01

    Fault detection and isolation are very important elements in the design of fault-tolerant decision support systems for ship operator guidance. This study outlines remedies that can be applied for fault diagnosis, when the ship responses are assumed to be linear in the wave excitation. A novel num...

  15. Modeling the Fault Tolerant Capability of a Flight Control System: An Exercise in SCR Specification

    Science.gov (United States)

    Alexander, Chris; Cortellessa, Vittorio; DelGobbo, Diego; Mili, Ali; Napolitano, Marcello

    2000-01-01

    In life-critical and mission-critical applications, it is important to make provisions for a wide range of contingencies, by providing means for fault tolerance. In this paper, we discuss the specification of a flight control system that is fault tolerant with respect to sensor faults. Redundancy is provided by analytical relations that hold between sensor readings; depending on the conditions, this redundancy can be used to detect, identify and accommodate sensor faults.

  16. Benchmarking an expert fault detection and diagnostic system on the Three Mile Island accident event sequence

    OpenAIRE

    Cilleirs, A.C.

    2013-01-01

    Early fault identification systems enable detecting and diagnosing early onset faults or fault causes which allow maintenance planning on the equipment showing signs of deterioration or failure. This includes valve and leaks and small cracks in steam generator tubes usually detected by means of ultrasonic inspection. We have shown (Cilliers and Mulder, 2012) that detecting faults early during transient operation in NPPs is possible when coupled with a reliable reference to compare...

  17. Automated Fault Diagnostics, Prognostics, and Recovery in Spacecraft Power Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fault detection and isolation (FDI) in spacecraft's electrical power system (EPS) has always received special attention. However, the power systems health...

  18. Important factors affecting fault detection coverage in probabilistic safety assessment of digital instrumentation and control systems

    International Nuclear Information System (INIS)

    As digital instrumentation and control (I and C) systems are gradually introduced into nuclear power plants (NPPs), concerns about the I and C systems’ reliability and safety are growing. Fault detection coverage is one of the most critical factors in the probabilistic safety assessment (PSA) of digital I and C systems. To correctly estimate the fault detection coverage, it is first necessary to identify important factors affecting it. From experimental results found in the literature and the authors’ experience in fault injection experiments on digital systems, four system-related factors and four fault-related factors are identified as important factors affecting the fault detection coverage. A fault injection experiment is performed to demonstrate the dependency of fault detection coverage on some of the identified important factors. The implications of the experimental results on the estimation of fault detection coverage for the PSA of digital I and C systems are also explained. The set of four system-related factors and four fault-related factors is expected to provide a framework for systematically comparing and analyzing various fault injection experiments and the resultant estimations on fault detection coverage of digital I and C systems in NPPs. (author)

  19. Fault Detection and Diagnosis System for the Air-conditioning

    Science.gov (United States)

    Nakahara, Nobuo

    The fault detection and diagnosis system, the FDD system, for the HVAC was initiated around the middle of 1970s in Japan but it still remains at the elementary stage. The HVAC is really one of the most complicated and large scaled system for the FDD system. Besides, the maintenance engineering was never focussed as the target of the academic study since after the war, but the FDD system for some kinds of the components and subsystems has been developed for the sake of the practical industrial needs. Recently, international cooperative study in the IEA Annex 25 on the energy conservation for the building and community targetted on the BOFD, the building optimization, fault detection and diagnosis. Not a few academic peaple from various engineering field got interested and, moreover, some national projects seem to start in the European countries. The author has reviewed the state of the art of the FDD and BO as well based on the references and the experience at the IEA study.

  20. Study on intelligent fault diagnosis system of nuclear power plants based on information fusion technique

    International Nuclear Information System (INIS)

    The technology of information fusion is used in the fault diagnosis for ship nuclear power plants in this paper. The space fusion structure is built based on fault tree expert system, NN diagnosis system, and mechanism model validation system. Not only the system deep-level knowledge, but also the shallow knowledge and the mechanism model knowledge are fully used. The simulation validation and verification showed that the information fusion diagnosis system could improve the fault diagnosis reliability effectively. (authors)

  1. ISHM-oriented adaptive fault diagnostics for avionics based on a distributed intelligent agent system

    Science.gov (United States)

    Xu, Jiuping; Zhong, Zhengqiang; Xu, Lei

    2015-10-01

    In this paper, an integrated system health management-oriented adaptive fault diagnostics and model for avionics is proposed. With avionics becoming increasingly complicated, precise and comprehensive avionics fault diagnostics has become an extremely complicated task. For the proposed fault diagnostic system, specific approaches, such as the artificial immune system, the intelligent agents system and the Dempster-Shafer evidence theory, are used to conduct deep fault avionics diagnostics. Through this proposed fault diagnostic system, efficient and accurate diagnostics can be achieved. A numerical example is conducted to apply the proposed hybrid diagnostics to a set of radar transmitters on an avionics system and to illustrate that the proposed system and model have the ability to achieve efficient and accurate fault diagnostics. By analyzing the diagnostic system's feasibility and pragmatics, the advantages of this system are demonstrated.

  2. Rconfigurable adaptive fuzzy fault-hiding control for greenhouse climate control system

    DEFF Research Database (Denmark)

    Hameed, Ibrahim; El-Madbouly, E I; Abdo, M I

    2016-01-01

    Modern greenhouses are equipped with different components for providing a comfortable climate for plant growth. A component malfunction may result in loss of production. Therefore, it is desirable to design a control system, which is stable, and is able to provide an acceptable degraded performance...... even in the faulty case. In this paper, an active fault tolerant control scheme to compensate for actuator and/or sensor faults in the greenhouse climate system is designed. The control system consists of a sensitive and reliable Fault Detection and Diagnosis (FDD) mechanism for different types of...... faults in presence of system disturbances and a robust reconfigurable control design based on fault-hiding principal in which the fault is hidden from the nominal controller and the fault effects are compensated. In this approach, a set of virtual actuators and virtual sensors are used to guarantee the...

  3. Industrial Cost-Benefit Assessment for Fault-tolerant Control Systems

    DEFF Research Database (Denmark)

    Thybo, C.; Blanke, M.

    1998-01-01

    Economic aspects are decisive for industrial acceptance of research concepts including the promising ideas in fault tolerant control. Fault tolerance is the ability of a system to detect, isolate and accommodate a fault, such that simple faults in a sub-system do not develop into failures at a...... system level. In a design phase for an industrial system, possibilities span from fail safe design where any single point failure is accommodated by hardware, over fault-tolerant design where selected faults are handled without extra hardware, to fault-ignorant design where no extra precaution is taken...... against failure. The paper describes the assessments needed to find the right path for new industrial designs. The economic decisions in the design phase are discussed: cost of different failures, profits associated with available benefits, investments needed for development and life-time support. The...

  4. Fault Self-Diagnosis for Modular Robotic Systems Using M-Lattice Modules

    Directory of Open Access Journals (Sweden)

    Enguang Guan

    2015-04-01

    Full Text Available In the domain of modular robotic systems, self-configuration, self-diagnosis and self-repair are known to be highly challenging tasks. This paper presents a novel fault self-diagnosis strategy which consists of two parts: fault detection and fault message transmission. In fault detection, a bionic synchronization ‘healthy heartbeat’ method is used to guarantee the high efficiency of the exogenous detection strategy. For fault message transmission, the Dijkstra method is modified to be capable of guiding the passage of fault messages along the optimal path. In a modular robotic system, fault message transmission depends mainly on local communications between adjacent modules, so there is no need for global broadcast information. Computational simulations of one system form, M-Lattice, have demonstrated the practical effectiveness of the proposed strategy. The strategy should be applicable in modular robotic systems in general.

  5. Fault Estimation

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.

    2002-01-01

    This paper presents a range of optimization based approaches to fault diagnosis. A variety of fault diagnosis prob-lems are reformulated in the so-called standard problem setup introduced in the literature on robust control. Once the standard problem formulations are given, the fault diagnosis pr...... problems can be solved by standard optimization tech-niques. The proposed methods include: (1) fault diagnosis (fault estimation, (FE)) for systems with model uncertainties; (2) FE for systems with parametric faults, and (3) FE for a class of nonlinear systems....

  6. Characteristics of earth faults in power systems with a compensated or an unearthed neutral

    Energy Technology Data Exchange (ETDEWEB)

    Haenninen, S.; Lehtonen, M. [VTT Energy, Espoo (Finland); Antila, E. [ABB Transmit Oy (Finland); Stroem, J. [Espoo Electricity Co (Finland); Ingman, S. [Vaasa Electricity Co (Finland)

    1998-08-01

    The most common fault type in the electrical distribution networks is the single phase to earth fault. For instance in the Nordic countries, about 80 % of all faults are of this type. To develop the protection and fault location systems, it is important to obtain real case data of disturbances and faults which occurred in the networks. Therefore, data of fault occurrences have been recorded and analyzed in the medium voltage distribution networks (20 kV) at two substations, of which one has an isolated and the other a compensated neutral. In the occurring disturbances, the traces of phase currents and neutral currents in the beginning of two feeder and the traces of phase voltages and neutral voltage from the voltage measuring bay were recorded. In addition to the measured data, other information of the fault occurrences was also collected (data of the line, cause and location of permanent faults and so on)

  7. A Fuzzy Mathematics Based Fault Auto-diagnosis System for Vacuum Resin Shot Dosing Equipment

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    On the basis of the analysis of faults and their causes of vacuum resin shot dosing equipment, the fuzzy model of fault diagnosis for the equipment is constructed, and the fuzzy relationship matrix, the symptom fuzzy vector, the fuzzy compound arithmetic operator, and the diagnosis principle of the model are determined. Then the fault auto-diagnosis system for the equipment is designed, and the functions for real-time monitoring its operation condition and for fault auto-diagnosis are realized. Finally, the experiments of fault auto-diagnosis are conducted in practical production and the veracity of the system is verified.

  8. Slip rate variability over the Holocene period in the middle Aterno fault system (Italy), retrieved from in situ 36Cl cosmogenic nuclide dating of exhumed fault-plane.

    Science.gov (United States)

    Tesson, Jim; Benedetti, Lucilla; Pucci, Stefano; Villani, Fabio; Bourles, Didier; Keddadouche, Karim; Aumaitre, Georges

    2016-04-01

    Numerous numerical modeling studies have described and quantified non-stochastic spatio-temporal variations of earthquake occurrences within fault-networks, such as temporal clustered earthquakes or fault synchronization. However, very few long-enough paleoseismological and geological records are available to test those models against well-constrained dataset and thus account for such variability in the fault behavior. The prerequisites for improving our understanding of fault-rupture processes and thus our capacity to better assess seismic hazard are to acquire paleoseismological records that enable to derive both long-term slip-rate and short-term variability, on a large population of faults and/or within a fault system. These conditions met in Central Apennines, an extensional province where substantial paleoseismological dataset accurately described the Holocene seismic history of a dense network of normal faults. In this study we use 36Cl in situ cosmogenic nuclide to retrieve the seismic history of 3 faults belonging to the Middle Aterno fault system, from north to south: the Bazzano fault, the Roccapreturo fault and the Sulmona fault, a portion of which ruptured during the 2009 L'Aquila earthquake in Italy. We use a new modeling approach to determine the age and slip of past seismic events from the 36Cl concentration profiles. This model is based on an inverse approach and uses an optimization algorithm enabling all the parameter space (number of events, age and slip of events, pre-exposure) to be explored without a priori constraints (see Tesson et al. in session TS4.2/NH4.16/SM3.8). Using this new approach, we precisely determine the slip events occurrences over the Holocene period of those three faults. The results indicate that the three studied faults have ruptured between 4.5 and 5.5 ka, while the southernmost part of the system has also ruptured between at 1.5-3 ka (Sulmona fault and southern segment of Roccapreturo). Those results are in agreement

  9. Knowledge-based fault diagnosis system for refuse collection vehicle

    International Nuclear Information System (INIS)

    The refuse collection vehicle is manufactured by local vehicle body manufacturer. Currently; the company supplied six model of the waste compactor truck to the local authority as well as waste management company. The company is facing difficulty to acquire the knowledge from the expert when the expert is absence. To solve the problem, the knowledge from the expert can be stored in the expert system. The expert system is able to provide necessary support to the company when the expert is not available. The implementation of the process and tool is able to be standardize and more accurate. The knowledge that input to the expert system is based on design guidelines and experience from the expert. This project highlighted another application on knowledge-based system (KBS) approached in trouble shooting of the refuse collection vehicle production process. The main aim of the research is to develop a novel expert fault diagnosis system framework for the refuse collection vehicle

  10. Knowledge-based fault diagnosis system for refuse collection vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Tan, CheeFai; Juffrizal, K.; Khalil, S. N.; Nidzamuddin, M. Y. [Centre of Advanced Research on Energy, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, Durian Tunggal, Melaka (Malaysia)

    2015-05-15

    The refuse collection vehicle is manufactured by local vehicle body manufacturer. Currently; the company supplied six model of the waste compactor truck to the local authority as well as waste management company. The company is facing difficulty to acquire the knowledge from the expert when the expert is absence. To solve the problem, the knowledge from the expert can be stored in the expert system. The expert system is able to provide necessary support to the company when the expert is not available. The implementation of the process and tool is able to be standardize and more accurate. The knowledge that input to the expert system is based on design guidelines and experience from the expert. This project highlighted another application on knowledge-based system (KBS) approached in trouble shooting of the refuse collection vehicle production process. The main aim of the research is to develop a novel expert fault diagnosis system framework for the refuse collection vehicle.

  11. Fault tree analysis on BWR core spray system

    International Nuclear Information System (INIS)

    Fault Trees which describe the failure modes for the Core Spray System function in the Browns Ferry Nuclear Plant (BWR 1065MWe) were developed qualitatively and quantitatively. The unavailability for the Core Spray System was estimated to be 1.2 x 10-3/demand. It was found that the miscalibration of four reactor pressure sensors or the failure to open of the two inboard valves (FCV 75-25 and 75-53) could reduce system reliability significantly. It was recommended that the pressure sensors would be calibrated independently. The introduction of the redundant inboard valves could improve the system reliability. Thus this analysis method was verified useful for system analysis. The detailed test and maintenance manual and the informations on the control logic circuits of each active component are necessary for further analysis. (author)

  12. Knowledge-based fault diagnosis system for refuse collection vehicle

    Science.gov (United States)

    Tan, CheeFai; Juffrizal, K.; Khalil, S. N.; Nidzamuddin, M. Y.

    2015-05-01

    The refuse collection vehicle is manufactured by local vehicle body manufacturer. Currently; the company supplied six model of the waste compactor truck to the local authority as well as waste management company. The company is facing difficulty to acquire the knowledge from the expert when the expert is absence. To solve the problem, the knowledge from the expert can be stored in the expert system. The expert system is able to provide necessary support to the company when the expert is not available. The implementation of the process and tool is able to be standardize and more accurate. The knowledge that input to the expert system is based on design guidelines and experience from the expert. This project highlighted another application on knowledge-based system (KBS) approached in trouble shooting of the refuse collection vehicle production process. The main aim of the research is to develop a novel expert fault diagnosis system framework for the refuse collection vehicle.

  13. Fault detection system for Argentine Research Reactor instrumentation

    Science.gov (United States)

    Polenta, Héctor P.; Bernard, John A.; Ray, Asok

    1993-01-01

    The design and implementation of a redundancy management scheme for the on-line detection and isolation of faulty sensors is presented. Such a device is potentially useful in reactor-powered spacecraft for enhancing the processing capabilities of the main computer. The fault detection device can be used as an integral part of intelligent instrumentation systems. The device has been built using an 8-bit microcontroller and commercially available electronic hardware. The software is completely portable. The operation of this device has been successfully demonstrated for real-time validation of sensor data on Argentina's RA-1 Research Reactor.

  14. Fault detection system for Argentine Research Reactor instrumentation

    International Nuclear Information System (INIS)

    The design and implementation of a redundancy management scheme for the on-line detection and isolation of faulty sensors is presented. Such a device is potentially useful in reactor-powered spacecraft for enhancing the processing capabilities of the main computer. The fault detection device can be used as an integral part of intelligent instrumentation systems. The device has been built using an 8-bit microcontroller and commercially available electronic hardware. The software is completely portable. The operation of this device has been successfully demonstrated for real-time validation of sensor data on Argentina's RA-1 Research Reactor

  15. Design of fault diagnosis system for inertial navigation system based on virtual technology

    Science.gov (United States)

    Hu, Baiqing; Wang, Boxiong; Li, An; Zhang, Mingzhao; Qin, Fangjun; Pan, Hua

    2006-11-01

    With regard to the complex structure of the inertial navigation system and the low rate of fault detection with BITE (built-in test equipment), a fault diagnosis system for INS based on virtual technologies (virtual instrument and virtual equipment) is proposed in this paper. The hardware of the system is a PXI computer with highly stable performance and strong extensibility. In addition to the basic functions of digital multimeter, oscilloscope and cymometer, it can also measure the attitude of the ship in real-time, connect and control the measurement instruments with digital interface. The software is designed with the languages of Measurement Studio for VB, JAVA, and CULT3D. Using the extensively applied fault-tree reasoning and fault cases makes fault diagnosis. To suit the system to the diagnosis for various navigation electronic equipments, the modular design concept is adopted for the software programming. Knowledge of the expert system is digitally processed and the parameters of the system's interface and the expert diagnosis knowledge are stored in the database. The application shows that system is stable in operation, easy to use, quick and accurate in fault diagnosis.

  16. Incipient fault detection and identification in process systems using accelerating neural network learning

    International Nuclear Information System (INIS)

    The objective of this paper is to present the development and numerical testing of a robust fault detection and identification (FDI) system using artificial neural networks (ANNs), for incipient (slowly developing) faults occurring in process systems. The challenge in using ANNs in FDI systems arises because of one's desire to detect faults of varying severity, faults from noisy sensors, and multiple simultaneous faults. To address these issues, it becomes essential to have a learning algorithm that ensures quick convergence to a high level of accuracy. A recently developed accelerated learning algorithm, namely a form of an adaptive back propagation (ABP) algorithm, is used for this purpose. The ABP algorithm is used for the development of an FDI system for a process composed of a direct current motor, a centrifugal pump, and the associated piping system. Simulation studies indicate that the FDI system has significantly high sensitivity to incipient fault severity, while exhibiting insensitivity to sensor noise. For multiple simultaneous faults, the FDI system detects the fault with the predominant signature. The major limitation of the developed FDI system is encountered when it is subjected to simultaneous faults with similar signatures. During such faults, the inherent limitation of pattern-recognition-based FDI methods becomes apparent. Thus, alternate, more sophisticated FDI methods become necessary to address such problems. Even though the effectiveness of pattern-recognition-based FDI methods using ANNs has been demonstrated, further testing using real-world data is necessary

  17. The ground-fault detection system for DIII-D

    International Nuclear Information System (INIS)

    This paper presents a discussion of the ground-fault detecting systems on the DIII-D tokamak. The subsystems that must be monitored for an inadvertent ground include the toroidal and poloidal coil systems, the vacuum vessel, and the coil support structures. In general, one point of each coil is tied to coil/power supply ground through a current limiting resistor. For ground protection the current through this resistor is monitored using a dynamically feedback balanced Hall probe transducer from LEM Industries. When large inductive currents flow in closed loops near the the tokamak, the result is undesirable magnetic error fields in the plasma region and noise generation on signal cables. Therefore, attention must be paid to avoid closed loops in the design of the coil and vessel support structure. For DIII-D a concept of dual insulating breaks and a single-point ground for all structure elements was used to satisfy this requirement. The integrity of the support structure is monitored by a system which continuously attempts to couple a variable frequency waveform onto these single-point grounds. The presence of an additional ground completes the circuit resulting in current flow. A Rogowski coil is then used to track the unwanted ground path in order to eliminate it. Details of the ground fault detection circuitry, and a description of its operation will be presented

  18. The ground-fault detection system for DIII-D

    International Nuclear Information System (INIS)

    This paper presents a discussion of the ground-fault detection systems on the DIII-D tokamak. The subsystems that must be monitored for an inadvertent ground include the toroidal and poloidal coil systems, the vacuum vessel, and the coil support structures. In general, one point of each coil is tied to coil/power supply ground through a current limiting resistor. For ground protection the current through this resistor is monitored using a dynamically feedback balanced Hall probe transducer from LEM Industries. When large inductive currents flow in closed loops near the tokamak, the result is undesirable magnetic error fields in the plasma region and noise generation on signal cables. Therefore, attention must be paid to avoid closed loops in the design of the coil and vessel support structure. For DIII-D a concept of dual insulating breaks and a single-point ground for all structure elements was used to satisfy this requirement. The integrity of the support structure is monitored by a system which continuously attempts to couple a variable frequency waveform onto these single-point grounds. The presence of an additional ground completes the circuit resulting in current flow. A Rogowski coil is then used to track the unwanted ground path in order to eliminate it. Details of the ground fault detection circuitry, and a description of its operation will be presented. 2 refs., 7 figs

  19. Fault Prediction in Object Oriented System Using the Coupling and Cohesion of Classes

    Directory of Open Access Journals (Sweden)

    Mr. Amol S. Dange

    2011-08-01

    Full Text Available Building efficient systems is one of the main challenges for softwaredevelopers, who have been concerned with dependability-related issues asthey built and deployed. Lots of changes often needs including the nature offaults and failures and the complexity of systems. Sometimes acceptingminor errors always need efforts to eliminate faults that might cause them isin the core of dependability. To this end various fault tolerance mechanismshave been investigated by researchers and used in industry. Unfortunately,more often than not these solutions exclusively focus on the implementation,ignoring other development phases, most importantly the earlier ones. Thiscreates a dangerous gap between the requirement to build dependable (andfault prediction systems and the fact that it is not dealt with until theimplementation step.A current software engineering gives attention towards only normal behaviorwith assumption that all faults can be removed during development. In factevery phase SDLC needs to be focused with phase-specific fault detectionmeans.We mean to conclude that SDLC requires: Integration of fault detection starting from requirement andarchitecture. Making fault detection-related decisions at each phase by explicitmodeling of faults. Developing dedicated tools for fault detection modeling; providingdomain-specific application-level fault prediction mechanisms.Part I: Fault Prediction engineering: from requirements to codePart II: Languages and Tools for engineering fault prediction systems

  20. Fault Location Estimation in Power Systems with Universal Intelligent Tuning

    OpenAIRE

    Kawady, Tamer Amin Said

    2005-01-01

    The general aim of this thesis is to develop an accurate fault location scheme that can solve the practical problems affecting the accuracy of the existing conventional fault locators. Firstly, a thorough investigation of the performance of the well known fault location methods was performed aiming to visualize the basic characteristics of the fault location estimation procedure. As can be seen from this study, the mutual coupling among the adjacent conductors is a serious problem. Thus, it r...

  1. Robustness Evaluation of Software Systems through Fault Injection

    OpenAIRE

    Di Leo, Domenico

    2013-01-01

    Over the last decades, software has been introduced in desperate safety domains, such as automotive, avionics and railways, just to name a few. For these domains, software is demanded to be highly robust to hardware faults and software faults since its failure may endanger human life, harm the environment, or cause economical loss. Fault injection, the deliberate inoculation of faults, is a powerful means to assess the robustness of software components that goes far beyond traditional test...

  2. Tsunamigenic potential of Mediterranean fault systems and active subduction zones

    Science.gov (United States)

    Petricca, Patrizio; Babeyko, Andrey

    2016-04-01

    Since the North East Atlantic and Mediterranean Tsunami Warning System (NEAMTWS) is under development by the European scientific community, it becomes necessary to define guidelines for the characterization of the numerous parameters must be taken into account in a fair assessment of the risk. Definition of possible tectonic sources and evaluation of their potential is one of the principal issues. In this study we systematically evaluate tsunamigenic potential of up-to-now known real fault systems and active subduction interfaces in the NEAMTWS region. The task is accomplished by means of numerical modeling of tsunami generation and propagation. We have simulated all possible uniform-slip ruptures populating fault and subduction interfaces with magnitudes ranging from 6.5 up to expected Mmax. A total of 15810 individual ruptures were processed. For each rupture, a tsunami propagation scenario was computed in linear shallow-water approximation on 1-arc minute bathymetric grid (Gebco_08) implying normal reflection boundary conditions. Maximum wave heights at coastal positions (totally - 23236 points of interest) were recorded for four hours of simulation and then classified according to currently adopted warning level thresholds. The resulting dataset allowed us to classify the sources in terms of their tsunamigenic potential as well as to estimate their minimum tsunamigenic magnitude. Our analysis shows that almost every source in the Mediterranean Sea is capable to produce local tsunami at the advisory level (i.e., wave height > 20 cm) starting from magnitude values of Mw=6.6. In respect to the watch level (wave height > 50 cm), the picture is less homogeneous: crustal sources in south-west Mediterranean as well as East-Hellenic arc need larger magnitudes (around Mw=7.0) to trigger watch levels even at the nearby coasts. In the context of the regional warning (i.e., source-to-coast distance > 100 km) faults also behave more heterogeneously in respect to the minimum

  3. Data-driven design of fault diagnosis systems nonlinear multimode processes

    CERN Document Server

    Haghani Abandan Sari, Adel

    2014-01-01

    In many industrial applications early detection and diagnosis of abnormal behavior of the plant is of great importance. During the last decades, the complexity of process plants has been drastically increased, which imposes great challenges in development of model-based monitoring approaches and it sometimes becomes unrealistic for modern large-scale processes. The main objective of Adel Haghani Abandan Sari is to study efficient fault diagnosis techniques for complex industrial systems using process historical data and considering the nonlinear behavior of the process. To this end, different methods are presented to solve the fault diagnosis problem based on the overall behavior of the process and its dynamics. Moreover, a novel technique is proposed for fault isolation and determination of the root-cause of the faults in the system, based on the fault impacts on the process measurements. Contents Process monitoring Fault diagnosis and fault-tolerant control Data-driven approaches and decision making Target...

  4. Fault Rid Through Protection of DFIG Based Wind Generation System

    Directory of Open Access Journals (Sweden)

    S. Sajedi

    2012-03-01

    Full Text Available This study proposes a fault ride-through strategy for a Doubly Fed Induction Generator (DFIG to enhance network stability during grid disturbances. To enable efficient computation a reduced order DFIG model is developed that restricts the calculation to the fundamental frequency component. However, the model enhancement introduced in the paper allows the consideration of the alternating components of the rotor current as well which is necessary for triggering the crowbar operation. As protection against short circuit transients, the crowbar protection is employed in the simulation. An equivalent model is constructed. Simplifications are made so as to have a system composed of grid, transformer, line and generator represented by elementary circuit elements (R, L, C and voltage sources. Equivalent circuit models are simplified so that the fault models may be used for synchronous machine parameters. It is assumed that the mechanical system cannot respond during the short time of a three phase short circuit. Simulation results in MATLABSimulink software are presented for model verification purposes.

  5. Distributed Evaluation Functions for Fault Tolerant Multi-Rover Systems

    Science.gov (United States)

    Agogino, Adrian; Turner, Kagan

    2005-01-01

    The ability to evolve fault tolerant control strategies for large collections of agents is critical to the successful application of evolutionary strategies to domains where failures are common. Furthermore, while evolutionary algorithms have been highly successful in discovering single-agent control strategies, extending such algorithms to multiagent domains has proven to be difficult. In this paper we present a method for shaping evaluation functions for agents that provide control strategies that both are tolerant to different types of failures and lead to coordinated behavior in a multi-agent setting. This method neither relies of a centralized strategy (susceptible to single point of failures) nor a distributed strategy where each agent uses a system wide evaluation function (severe credit assignment problem). In a multi-rover problem, we show that agents using our agent-specific evaluation perform up to 500% better than agents using the system evaluation. In addition we show that agents are still able to maintain a high level of performance when up to 60% of the agents fail due to actuator, communication or controller faults.

  6. Benchmarking an expert fault detection and diagnostic system on the Three Mile Island accident event sequence

    International Nuclear Information System (INIS)

    Highlights: • Attempt was to use available resources at a nuclear plant in a value added fashion. • Includes plant measurement data and plant training and engineering simulator capabilities. • Correlating fault detection data for systems to develop of a deterministic fault identifications system. • After implementing a host of data manipulation algorithms, the results provided more information on the fault than expected. • TMI benchmark results in value added to the operator and system. - Abstract: Early fault identification systems enable detecting and diagnosing early onset faults or fault causes which allow maintenance planning on the equipment showing signs of deterioration or failure. This includes valve and leaks and small cracks in steam generator tubes usually detected by means of ultrasonic inspection. We have shown (Cilliers and Mulder, 2012) that detecting faults early during transient operation in NPPs is possible when coupled with a reliable reference to compare plant measurements with during transients. We have also shown (Cilliers, 2013) that by correlating the fault detection information as received from distributed systems it is possible to diagnose the faults in terms of location and magnitude. This paper makes use of the techniques and processes developed in the previous papers and apply it to a case study of the Three Mile Island accident. In this way we can determine how the improved information available could present the operator with a better idea to the state of the plant during situations where a combination of faults and transients prevents the operator and conventional systems to recognise the abnormal behaviour

  7. Expert system application to fault diagnosis and procedure synthesis

    International Nuclear Information System (INIS)

    Two knowledge based systems have been developed to detect plant faults, to validate sensor data in a nuclear power plant, and to synthesize procedures to assure safety goals are met when a transient occurs. These two systems are being combined into a single system through a Plant Status Monitoring System (PSMS) and a common database accessed by all the components of the integrated system. The system is designed to sit on top of an existing Safety Parameter Display System (SPDS), and to use the existing data acquisition and data control software of the SPDS. The integrated system will communicate with the SPDS software through a single database. This database will receive sensor values and equipment status indications in a form acceptable to the knowledge based system and according to an update plan designed specifically for the system. PSMS will monitor the plant status by scanning the system database continuously, and will respond to the changes in the plant data according to three priorities: direct indications of plant changes that can be resolved by simple actions such as assuring that a back up pump has been started; more complex indications that lead to entry conditions for predefined event procedures or other individual system recovery procedures; and plant conditions that are defined as the entry points to the symptomatic emergency procedure guidelines (EPGs). At present, the knowledge base is being built using scenarios run on a BWR-6 plant referenced simulator. Concurrently, software is being developed for performing diagnosis and procedure synthesis

  8. Data from theodolite measurements of creep rates on San Francisco Bay region faults, California, 1979-2012

    Science.gov (United States)

    McFarland, Forrest S.; Lienkaemper, James J.; Caskey, S. John

    2009-01-01

    Our purpose is to annually update our creep-data archive on San Francisco Bay region active faults for use by the scientific research community. Earlier data (1979-2001) were reported in Galehouse (2002) and were analyzed and described in detail in a summary report (Galehouse and Lienkaemper, 2003). A complete analysis of our earlier results obtained on the Hayward Fault was presented in Lienkaemper, Galehouse and Simpson (2001) and updated in Lienkaemper and others (2012). Lienkaemper and others (2014a) provide a new overview and analysis of fault creep along all sections of the northern San Andreas Fault system, from which they estimate by how much fault creep reduces the seismic hazard for each fault section.

  9. Study and Design of Diaphragm Pump Vibration Detection Fault Diagnosis System Based on FFT

    OpenAIRE

    Jia Yin; Jiande Wu; Xuyi Yuan; Xiaodong Wang; Yugang Fan

    2013-01-01

    This study has proposed a fault diagnosis system based on vibration detection. The system mainly includes four modules: signal acquisition module, signal processing module, state identification module, fault diagnosis and alarm module. The system uses CMSS 2200 acceleration sensor to collect vibration signals, processing spectrum with FFT (Fast Fourier Transform) which is used effectively in current industry and finally achieve fault diagnosis and prediction for diaphragm pump. Through collec...

  10. A Reliable Fault-Tolerant Scheduling Algorithm for Real Time Embedded Systems

    OpenAIRE

    Arar, Chafik; Kalla, Hamoudi; Kalla, Salim; Riadh, Hocine

    2013-01-01

    In this paper, we propose a fault-tolerant scheduling for realtime embedded systems. Our scheduling algorithm is dedicated to multibus heterogeneous architectures, which take as input a given system description and a given fault hypothesis. It is based on a data fragmentation and passive redundancy, which allow fast fault detection/retransmission and efficient use of buses. Our scheduling approach consist of a list scheduling heuristic based on a Global System Failure Rate (GSFR). In order to...

  11. Oblique Fault Systems Crossing the Seattle Basin: Seismic and Aeromagnetic Evidence for Additional Shallow Fault Systems in the Central Puget Lowland

    Science.gov (United States)

    Keranen, K. M.; Mace, C.

    2011-12-01

    Upper-plate seismicity in the Puget Lowland is more broadly distributed than mapped fault systems and presents a conundrum for understanding the active tectonics of the region. Although many previous studies have mapped faulting in the Puget Lowland from subsurface geophysical data, many of these efforts have focused specifically on mapping the structure of the Seattle Fault Zone and the South Whidbey Island Fault. The thick glacial sediments and extensive water bodies may conceal additional active faults away from these major structures. To extend the results of the previous work, we mapped fault networks and patterns of sediment deposition in Quaternary sediments broadly throughout the central Puget Lowland using a combination of existing multi-channel seismic reflection datasets with widely distributed profiles and aeromagnetic data. We identify a NE-SW zone of high-angle faulting and shallow sediment deformation crossing the Seattle Uplift and the Seattle Basin that segments the Seattle Fault Zone (SFZ), offsetting aeromagnetic anomalies along the SFZ by 1.2 km in a dextral sense. Aeromagnetic lineations trace the NE-SW trend of deformation across the Seattle Uplift and connect deformation within the Puget Sound and the Hood Canal. Two additional zones of faulting trend NW-SE and cut through the Seattle Basin and the Kingston Arch, respectively. We also interpreted five regional seismic horizons, representing erosional unconformities, throughout our dataset, and created sediment thickness maps for each time interval. The thickness maps reveal changing patterns of sediment deposition through time, possibly controlled by changes in the regional pattern of deformation. Holocene sediment deposition shows strong control by the oblique fault systems. These oblique fault structures may be partially responsible for the wide distribution of seismicity within the central Puget Lowland.

  12. Adaptive fault-tolerant control of linear systems with actuator saturation and L2-disturbances

    Institute of Scientific and Technical Information of China (English)

    Wei GUAN; Guanghong YANG

    2009-01-01

    This paper studies the problem of designing adaptive fault-tolerant H-infinity controllers for linear timeinvariant systems with actuator saturation. The disturbance tolerance ability of the closed-loop system is measured by an optimal index. The notion of an adaptive H-infinity performance index is proposed to describe the disturbance attenuation performances of closed-loop systems. New methods for designing indirect adaptive fault-tolerant controllers via state feedback are presented for actuator fault compensations. Based on the on-line estimation of eventual faults, the adaptive fault-tolerant controller parameters are updated automatically to compensate for the fault effects on systems. The designs are developed in the framework of the linear matrix inequality (LMI) approach, which can guarantee the disturbance tolerance ability and adaptive H-infinity performances of closed-loop systems in the cases of actuator saturation and actuator failures. An example is given to illustrate the efficiency of the design method.

  13. Fault Diagnosis Scheme for Nonlinear Stochastic Systems with Time-Varying Fault: Application to the Rigid Spacecraft Control

    Czech Academy of Sciences Publication Activity Database

    Nguyen, H.Q.; Čelikovský, Sergej

    2012-01-01

    Roč. 1, č. 3 (2012), s. 179-187. ISSN 2223-7038 R&D Projects: GA ČR(CZ) GAP103/12/1794 Institutional support: RVO:67985556 Keywords : Attitude control * adaptive fault estimation * LMI * PDF Subject RIV: BC - Control System s Theory http://lib.physcon.ru/doc?id=02c925f7e4ab

  14. Fault Feature Analysis of a Cracked Gear Coupled Rotor System

    Directory of Open Access Journals (Sweden)

    Hui Ma

    2014-01-01

    Full Text Available Considering the misalignment of gear root circle and base circle and accurate transition curve, an improved mesh stiffness model for healthy gear is proposed, and it is validated by comparison with the finite element method. On the basis of the improved method, a mesh stiffness model for a cracked gear pair is built. Then a finite element model of a cracked gear coupled rotor system in a one-stage reduction gear box is established. The effects of crack depth, width, initial position, and crack propagation direction on gear mesh stiffness, fault features in time domain and frequency domain, and statistical indicators are investigated. Moreover, fault features are also validated by experiment. The results show that the improved mesh stiffness model is more accurate than the traditional mesh stiffness model. When the tooth root crack appears, distinct impulses are found in time domain vibration responses, and sidebands appear in frequency domain. Amplitudes of all the statistical indicators ascend gradually with the growth of crack depth and width, decrease with the increasing crack initial position angle, and firstly increase and then decrease with the growth of propagation direction angle.

  15. Sensor and Actuator Fault-Hiding Reconfigurable Control Design for a Four-Tank System Benchmark

    DEFF Research Database (Denmark)

    Hameed, Ibrahim; El-Madbouly, Esam I; Abdo, Mohamed I

    2015-01-01

    is introduced. Faults are modeled as a drastic gain loss in actuators (i.e., pumps) and in sensor measurements (i.e., level detection) which could lead to a large loss in the nominal performance. A configurable decentralized Proportional Integral (PI) controller is designed and applied to a Linear Time......Fault detection and compensation plays a key role to fulfill high demands for performance and security in today's technological systems. In this paper, a fault-hiding (i.e., tolerant) control scheme that detects and compensates for actuator and sensor faults in a four-tank system benchmark...... Invariant (LTI) system where virtual sensors and virtual actuators are used to correct faulty performance through the use of a pre-fault performance. Simulation results showed that the developed approach can handle different types of faults and able to completely and instantly recover the original system...

  16. Software System for Finding the Incipient Faults in Power Transformers

    Directory of Open Access Journals (Sweden)

    Nikolina Petkova

    2015-05-01

    Full Text Available In this paper a new software system for finding of incipient faultsis presented.An experiment is made with real measurement of partial discharge(PD that appeared in power transformer. The software system usesacquisition data to define the real state of this transformer. One of the most important criteria for the power transformer’s state is the presence of partial discharges. The wave propagation caused by partial discharge depends on scheme of the winding and construction of the power equipment. In all cases, the PD source had a specific position so the wave measured from the PD –coupling device had a specific waveform. The waveform is different when PDcoupling device is put on a specific place. The waveform and the time of propagation are criteria for the localization of the source of incipient faults in the volume of power transformer.

  17. Self-organized criticality of power system faults and its application in adaptation to extreme climate

    Institute of Scientific and Technical Information of China (English)

    SU Sheng; LI YinHong; DUAN XianZhong

    2009-01-01

    This paper analyzes the statistics of faults in a transmission and distribution networks in central China, unveils long-term autocorrelation and power law distribution of power system faults, which indicates that power system fault has self-organized criticality (SOC) feature. The conclusion is consistent with the power systems data in 2008 with ice storm present. Since power systems cover large areas, climate is the key factor to its safety and stability. In-depth analysis shows that the SOC of atmosphere system contributes much to that of power system faults. Extreme climate will be more intense and frequent with global warming, it will have more and more impact upon power systems. The SOC feature of power system faults is utilized to develop approaches to facilitate power systems adaptation to climate varia-tion in an economical and efficient way.

  18. Andrea Ghez Receives Crafoord Prize

    OpenAIRE

    Sher, Ben

    2012-01-01

    The Royal Swedish Academy of Scienceshas selected Andrea Ghez, a professor of physics and astronomy at UCLA, to receive the 2012 Crafoord Prize in Astronomy. She is being honored by the Academy for “observations of stars orbiting the Galactic center, indicating the presence of a supermassive black hole.” The Crafoord Prize, which includes an accompanying award of 4 million Swedish krona, is considered one of the world’s largest scientific prizes. Ghez is the first woman to win the award since...

  19. Recent Research Progress in Fault Analysis of Complex Electric Power Systems

    Directory of Open Access Journals (Sweden)

    WANG, Z.

    2010-02-01

    Full Text Available In this paper, we adopt a novel approach to the fault analysis of complex electric power systems. Electric power system is one of the most complex artificial systems in the world. Its safe, steady, economical and reliable operating plays a very important part in guaranteeing socioeconomic development, and even in safeguarding social stability. The complexity of electric power system is determined by its characteristics about constitution, configuration, operation, organization, etc. No matter if, we adopt new analytical methods or technical means, we must have a distinct recognition of electric power system itself and its complexity, and increase analysis continuously, operation and control level. In this paper, utilizing real-time measurements of phasor measurement unit, based on graph theory and multivariate statistical analysis theory, we are using mainly Breadth-first search, Depth-first search and cluster analysis. Then, we seek for the uniform laws of marked changes of electrical quantities. Then we can carry out fast and exact analysis of fault component. Finally, we can accomplish fault isolation. According to line fault and bus-bar fault (single-phase fault, phase-to-phase fault and three-phase fault in complex electric power systems, we have carried out a great deal of simulation experiments and obtained ideal results. These researches have proven that the faults in complex electric power systems can be explored successfully by analysis and calculation based on graph theory and multivariate statistical analysis theory.

  20. Knowledge Processing Method of Fault Diagnosis Expert Systems for Letter Sorting Equipment

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the analysis of fault diagnosis knowledge of lettersorting machine, this paper proposes a processing method by which the fault diagnosis knowledge is divided into exact knowledge, inadequate knowledge and fuzzy knowledge. Then their presenting and implementing form in fault diagnosis expert system is discussed and studied. It is proved that the expert system has good feasibility in the field of the diagnosis of letter sorting machine.

  1. Method of Fault Area & Section Location for Non-solidly Earthed Distribution System

    Institute of Scientific and Technical Information of China (English)

    ZHENG Guping; JIANG Chao; LI Gang; QI Zheng; YANG Yihan

    2012-01-01

    Medium voltage distributions in China mainly use overhead lines; and most them are small current systems, whose single phase to-earth fault accounts for over 80% of the total failure in power grid. Fault monitoring is one of the main functions of distribution automation, so the new generation of power distribution automation systems in China should thoroughly solve the problem of the orientation of small current grounding fault.

  2. A fault detection and isolation scheme for industrial systems based on multiple operating models

    OpenAIRE

    Rodrigues, Mickael; THEILLIOL, DIDIER; Adam Medina, Manuel; Sauter, Dominique

    2008-01-01

    In this paper, a fault diagnosis method is developed for systems described by multi- models. The main contribution consists in the design of a new Fault Detection and Isolation scheme (FDI) through an adaptive filter for such systems. Based on the assumption that dynamic behavior of the process is described by a multi-model approach around different operating points, a set of residual is established in order to generate weighting functions robust to faults. These robust weighting functions ar...

  3. Passive Fault Tolerant Control of Piecewise Affine Systems Based on H Infinity Synthesis

    DEFF Research Database (Denmark)

    Gholami, Mehdi; Cocquempot, vincent; Schiøler, Henrik; Bak, Thomas

    2011-01-01

    In this paper we design a passive fault tolerant controller against actuator faults for discretetime piecewise affine (PWA) systems. By using dissipativity theory and H analysis, fault tolerant state feedback controller design is expressed as a set of Linear Matrix Inequalities (LMIs). In the cur...... current paper, the PWA system switches not only due to the state but also due to the control input. The method is applied on a large scale livestock ventilation model....

  4. Application of ENN-1 for Fault Diagnosis of Wind Power Systems

    OpenAIRE

    Meng-Hui Wang; Hung-Cheng Chen

    2012-01-01

    Maintaining a wind turbine and ensuring secure is not easy because of long-term exposure to the environment and high installation locations. Wind turbines need fully functional condition-monitoring and fault diagnosis systems that prevent accidents and reduce maintenance costs. This paper presents a simulator design for fault diagnosis of wind power systems and further proposes some fault diagnosis technologies such as signal analysis, feature selecting, and diagnosis methods. First, this pap...

  5. Dr Andrea Granelli, Vice President, Telecom Italia

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    Photo 06: Dr Andrea Granelli, Chief Executive Officer, Telecom Italia Lab (second from right) visiting the LHC superconducting magnet test hall with (from left to right) M. Cecchi , F. Gagliardi and G. Cavallari. Photo 15: Dr Andrea Granelli, Chief Executive Officer, Telecom Italia Lab (left) visiting the LHC superconducting magnet test hall with (from left to right) M. Cecchi and G. Cavallari.

  6. Design of a bilinear fault detection observer for singular bilinear systems

    Institute of Scientific and Technical Information of China (English)

    Zhanshan WANG; Huaguang ZHANG

    2007-01-01

    A bilinear fault detection observer is proposed for a class of continuous time singular bilinear systems subject to unknown input disturbance and fault.By singular value decomposition on the original system,a bilinear fault detection observer is proposed for the decomposed system via an algebraic Riccati equation,and the domain of attraction of the state estimation error is estimated.A design procedure is presented to determine the fault detection threshold.A model of flexible joint robot is used to demonstrate the effectiveness of the proposed method.

  7. An Ontology for Identifying Cyber Intrusion Induced Faults in Process Control Systems

    Science.gov (United States)

    Hieb, Jeffrey; Graham, James; Guan, Jian

    This paper presents an ontological framework that permits formal representations of process control systems, including elements of the process being controlled and the control system itself. A fault diagnosis algorithm based on the ontological model is also presented. The algorithm can identify traditional process elements as well as control system elements (e.g., IP network and SCADA protocol) as fault sources. When these elements are identified as a likely fault source, the possibility exists that the process fault is induced by a cyber intrusion. A laboratory-scale distillation column is used to illustrate the model and the algorithm. Coupled with a well-defined statistical process model, this fault diagnosis approach provides cyber security enhanced fault diagnosis information to plant operators and can help identify that a cyber attack is underway before a major process failure is experienced.

  8. Study on the intelligence fault diagnostic system for the nuclear power plant

    International Nuclear Information System (INIS)

    The fuzzy logic and neural network are combined in this paper, and setting up the fuzzy neural network (FNN); meanwhile, the distinct differences and connections between the fuzzy logic and neural network are compared. Furthermore, the algorithm and structure of the FNN are introduced. The FNN is applied to the nuclear power plant, and the fault diagnostic system of the nuclear power plant based on the FNN is built. The fault symptoms and the possibility of the inverted U-tube break accident of steam generator are discussed. In order to test the system's validity, the inverted U-tube break accident of steam generator is used as an example and many simulation experiments are performed. The test results show that the FNN could identify the fault. Moreover, the intelligence fault system can diagnose other faults of the nuclear power plant, and it can satisfy the demand of fault diagnosis. (authors)

  9. Sensor fault diagnosis for fast steering mirror system based on Kalman filter

    Science.gov (United States)

    Wang, Hongju; Bao, Qiliang; Yang, Haifeng; Tao, Sunjie

    2015-10-01

    In this paper, to improve the reliability of a two-axis fast steering mirror system with minimum hardware consumption, a fault diagnosis method based on Kalman filter was developed. The dynamics model of the two-axis FSM was established firstly, and then the state-space form of the FSM was adopted. A bank of Kalman filters for fault detection was designed based on the state-space form. The effects of the sensor faults on the innovation sequence were investigated, and a decision approach called weighted sum-squared residual (WSSR) was adopted to isolate the sensor faults. Sensor faults could be detected and isolated when the decision statistics changed. Experimental studies on a prototype system show that the faulty sensor can be isolated timely and accurately. Meanwhile, the mathematical model of FSM system was used to design fault diagnosis scheme in the proposed method, thus the consumption of the hardware and space is decreased.

  10. Experimental studies on intelligent fault detection and diagnosis using sensor networks on mechanical pneumatic systems

    Science.gov (United States)

    Zhang, Kunbo; Kao, Imin; Kambli, Sachin; Boehm, Christian

    2008-03-01

    Fault is a undesirable factor in any mechanical/pneumatic system. It affects the efficiency of system operation and reduces economic benefit in industry. The early detection and diagnosis of faults in a mechanical system becomes important for preventing failure of equipment and loss of productivity and profits. In this paper, we present our ongoing research results on intelligent fault detections and diagnosis (FDD) on mechanical/ pneumatic systems. Using data from sensors and sensor network in an integrated industrial system, our proposed FDD methodology provides the analysis of necessary sensory information (for example, flow rates and pressure, as well as other digital sensor data) for the detection and diagnosis of system fault. In this experimental study, the leakage of pneumatic cylinder was the "fault." It was shown that the FDD analysis was able to make diagnosis of leakage both in location and size of the fault. In addition, the systematic fault and localized faults can be detected separately. The proposed wavelet method gives rise to the fingerprint analysis to recognize the patterns of the flow rate and pressure data - a very useful tool in intelligent fault detection and diagnosis.

  11. From experiment to design -- Fault characterization and detection in parallel computer systems using computational accelerators

    Science.gov (United States)

    Yim, Keun Soo

    This dissertation summarizes experimental validation and co-design studies conducted to optimize the fault detection capabilities and overheads in hybrid computer systems (e.g., using CPUs and Graphics Processing Units, or GPUs), and consequently to improve the scalability of parallel computer systems using computational accelerators. The experimental validation studies were conducted to help us understand the failure characteristics of CPU-GPU hybrid computer systems under various types of hardware faults. The main characterization targets were faults that are difficult to detect and/or recover from, e.g., faults that cause long latency failures (Ch. 3), faults in dynamically allocated resources (Ch. 4), faults in GPUs (Ch. 5), faults in MPI programs (Ch. 6), and microarchitecture-level faults with specific timing features (Ch. 7). The co-design studies were based on the characterization results. One of the co-designed systems has a set of source-to-source translators that customize and strategically place error detectors in the source code of target GPU programs (Ch. 5). Another co-designed system uses an extension card to learn the normal behavioral and semantic execution patterns of message-passing processes executing on CPUs, and to detect abnormal behaviors of those parallel processes (Ch. 6). The third co-designed system is a co-processor that has a set of new instructions in order to support software-implemented fault detection techniques (Ch. 7). The work described in this dissertation gains more importance because heterogeneous processors have become an essential component of state-of-the-art supercomputers. GPUs were used in three of the five fastest supercomputers that were operating in 2011. Our work included comprehensive fault characterization studies in CPU-GPU hybrid computers. In CPUs, we monitored the target systems for a long period of time after injecting faults (a temporally comprehensive experiment), and injected faults into various types of

  12. Sensor Fault Masking of a Ship Propulsion System

    DEFF Research Database (Denmark)

    Wu, N. Eva; Thavamani, Shuda; Zhang, Youmin;

    2005-01-01

    This paper presents the results of a study on fault-tolerant control of a ship propulsion benchmark (Izadi-Zamanabadi and Blanke, 999), which uses estimated or virtual measurements as feedback variables. The estimator operates on a self-adjustable design model so that its outputs can be made immune...... fault, and a parametric fault, without having to alter the original controller in the benchmark....

  13. Sensor Fault Masking of a Ship Propulsion System

    DEFF Research Database (Denmark)

    Wu, N.E.; Thavamani, A.; Zhang, Y.;

    2003-01-01

    This paper presents the results of a study on fault-tolerant control of a ship propulsion benchmark (Izadi-Zamanabadi and Blanke, 1999), which uses estimated or virtual measurements as feedback variables. The estimator operates on a selfadjustable design model so that its outputs can be made immune...... incipient fault, and a parametric fault, without having to alter the original controller in the benchmark....

  14. Flexible fault ride through strategy for wind farm clusters in power systems with high wind power penetration

    International Nuclear Information System (INIS)

    Highlights: • A flexible fault ride through strategy is proposed. • The strategy comprises of grid code requirements and power restrictions. • Slight faults and moderate faults are the main defending objectives. • Temporary overloading capability of the doubly fed induction generator is considered. - Abstract: This paper investigates a flexible fault ride through strategy for power systems in China with high wind power penetration. The strategy comprises of adaptive fault ride through requirements and maximum power restrictions of the wind farms with weak fault ride through capabilities. The slight faults and moderate faults with high probability are the main defending objective of the strategy. The adaptive fault ride through requirement in the strategy consists of two sub fault ride through requirements, a temporary slight voltage ride through requirement corresponding to a slight fault incident, with a moderate voltage ride through requirement corresponding to a moderate fault. The temporary overloading capability of the wind farm is reflected in both requirements to enhance the capability to defend slight faults and to avoid tripping when the crowbar is disconnected after moderate faults are cleared. For those wind farms that cannot meet the adaptive fault ride through requirement, restrictions are put on the maximum power output. Simulation results show that the flexible fault ride through strategy increases the fault ride through capability of the wind farm clusters and reduces the wind power curtailment during faults

  15. From tomographic images to fault heterogeneities

    Directory of Open Access Journals (Sweden)

    A. Amato

    1994-06-01

    Full Text Available Local Earthquake Tomography (LET is a useful tool for imaging lateral heterogeneities in the upper crust. The pattern of P- and S-wave velocity anomalies, in relation to the seismicity distribution along active fault zones. can shed light on the existence of discrete seismogenic patches. Recent tomographic studies in well monitored seismic areas have shown that the regions with large seismic moment release generally correspond to high velocity zones (HVZ's. In this paper, we discuss the relationship between the seismogenic behavior of faults and the velocity structure of fault zones as inferred from seismic tomography. First, we review some recent tomographic studies in active strike-slip faults. We show examples from different segments of the San Andreas fault system (Parkfield, Loma Prieta, where detailed studies have been carried out in recent years. We also show two applications of LET to thrust faults (Coalinga, Friuli. Then, we focus on the Irpinia normal fault zone (South-Central Italy, where a Ms = 6.9 earthquake occurred in 1980 and many thousands of attershock travel time data are available. We find that earthquake hypocenters concentrate in HVZ's, whereas low velocity zones (LVZ’ s appear to be relatively aseismic. The main HVZ's along which the mainshock rupture bas propagated may correspond to velocity weakening fault regions, whereas the LVZ's are probably related to weak materials undergoing stable slip (velocity strengthening. A correlation exists between this HVZ and the area with larger coseismic slip along the fault, according to both surface evidence (a fault scarp as high as 1 m and strong ground motion waveform modeling. Smaller wave-length, low-velocity anomalies detected along the fault may be the expression of velocity strengthening sections, where aseismic slip occurs. According to our results, the rupture at the nucleation depth (~ 10-12 km is continuous for the whole fault lenoth (~ 30 km, whereas at shallow depth

  16. A discrete event systems approach to discriminating intermittent from permanent faults

    Directory of Open Access Journals (Sweden)

    Deng Guanqian

    2014-04-01

    Full Text Available Almost all work on model-based diagnosis (MBD potentially presumes faults are persistent and does not take intermittent faults (IFs into account. Therefore, it is common for diagnosis systems to misjudge IFs as permanent faults (PFs, which are the major cause of the problems of false alarms, cannot duplication and no fault found in aircraft avionics. To address this problem, a new fault model which includes PFs and IFs is presented based on discrete event systems (DESs. Thereafter, an approach is given to discriminate between PFs and IFs by diagnosing the current fault. In this paper, the regulations of (PFs and IFs fault evolution through fault and reset events along the traces of system are studied, and then label propagation function is modified to account for PFs and the dynamic behavior of IFs and diagnosability of PFs and IFs are defined. Finally, illustrative examples are presented to demonstrate the proposed approach, and the analysis results show the fault types can be discriminated within bounded delay if the system is diagnosable.

  17. Orion GN&C Fault Management System Verification: Scope And Methodology

    Science.gov (United States)

    Brown, Denise; Weiler, David; Flanary, Ronald

    2016-01-01

    In order to ensure long-term ability to meet mission goals and to provide for the safety of the public, ground personnel, and any crew members, nearly all spacecraft include a fault management (FM) system. For a manned vehicle such as Orion, the safety of the crew is of paramount importance. The goal of the Orion Guidance, Navigation and Control (GN&C) fault management system is to detect, isolate, and respond to faults before they can result in harm to the human crew or loss of the spacecraft. Verification of fault management/fault protection capability is challenging due to the large number of possible faults in a complex spacecraft, the inherent unpredictability of faults, the complexity of interactions among the various spacecraft components, and the inability to easily quantify human reactions to failure scenarios. The Orion GN&C Fault Detection, Isolation, and Recovery (FDIR) team has developed a methodology for bounding the scope of FM system verification while ensuring sufficient coverage of the failure space and providing high confidence that the fault management system meets all safety requirements. The methodology utilizes a swarm search algorithm to identify failure cases that can result in catastrophic loss of the crew or the vehicle and rare event sequential Monte Carlo to verify safety and FDIR performance requirements.

  18. Nonlinear dynamic failure process of tunnel-fault system in response to strong seismic event

    Science.gov (United States)

    Yang, Zhihua; Lan, Hengxing; Zhang, Yongshuang; Gao, Xing; Li, Langping

    2013-03-01

    Strong earthquakes and faults have significant effect on the stability capability of underground tunnel structures. This study used a 3-Dimensional Discrete Element model and the real records of ground motion in the Wenchuan earthquake to investigate the dynamic response of tunnel-fault system. The typical tunnel-fault system was composed of one planned railway tunnel and one seismically active fault. The discrete numerical model was prudentially calibrated by means of the comparison between the field survey and numerical results of ground motion. It was then used to examine the detailed quantitative information on the dynamic response characteristics of tunnel-fault system, including stress distribution, strain, vibration velocity and tunnel failure process. The intensive tunnel-fault interaction during seismic loading induces the dramatic stress redistribution and stress concentration in the intersection of tunnel and fault. The tunnel-fault system behavior is characterized by the complicated nonlinear dynamic failure process in response to a real strong seismic event. It can be qualitatively divided into 5 main stages in terms of its stress, strain and rupturing behaviors: (1) strain localization, (2) rupture initiation, (3) rupture acceleration, (4) spontaneous rupture growth and (5) stabilization. This study provides the insight into the further stability estimation of underground tunnel structures under the combined effect of strong earthquakes and faults.

  19. Evaluation of digital fault-tolerant architectures for nuclear power plant control systems

    International Nuclear Information System (INIS)

    Four fault tolerant architectures were evaluated for their potential reliability in service as control systems of nuclear power plants. The reliability analyses showed that human- and software-related common cause failures and single points of failure in the output modules are dominant contributors to system unreliability. The four architectures are triple-modular-redundant (TMR), both synchronous and asynchronous, and also dual synchronous and asynchronous. The evaluation includes a review of design features, an analysis of the importance of coverage, and reliability analyses of fault tolerant systems. An advantage of fault-tolerant controllers over those not fault tolerant, is that fault-tolerant controllers continue to function after the occurrence of most single hardware faults. However, most fault-tolerant controllers have single hardware components that will cause system failure, almost all controllers have single points of failure in software, and all are subject to common cause failures. Reliability analyses based on data from several industries that have fault-tolerant controllers were used to estimate the mean-time-between-failures of fault-tolerant controllers and to predict those failures modes that may be important in nuclear power plants. 7 refs., 4 tabs

  20. Award ER25750: Coordinated Infrastructure for Fault Tolerance Systems Indiana University Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lumsdaine, Andrew

    2013-03-08

    The main purpose of the Coordinated Infrastructure for Fault Tolerance in Systems initiative has been to conduct research with a goal of providing end-to-end fault tolerance on a systemwide basis for applications and other system software. While fault tolerance has been an integral part of most high-performance computing (HPC) system software developed over the past decade, it has been treated mostly as a collection of isolated stovepipes. Visibility and response to faults has typically been limited to the particular hardware and software subsystems in which they are initially observed. Little fault information is shared across subsystems, allowing little flexibility or control on a system-wide basis, making it practically impossible to provide cohesive end-to-end fault tolerance in support of scientific applications. As an example, consider faults such as communication link failures that can be seen by a network library but are not directly visible to the job scheduler, or consider faults related to node failures that can be detected by system monitoring software but are not inherently visible to the resource manager. If information about such faults could be shared by the network libraries or monitoring software, then other system software, such as a resource manager or job scheduler, could ensure that failed nodes or failed network links were excluded from further job allocations and that further diagnosis could be performed. As a founding member and one of the lead developers of the Open MPI project, our efforts over the course of this project have been focused on making Open MPI more robust to failures by supporting various fault tolerance techniques, and using fault information exchange and coordination between MPI and the HPC system software stack from the application, numeric libraries, and programming language runtime to other common system components such as jobs schedulers, resource managers, and monitoring tools.

  1. Fault Diagnosis for Nonlinear Hydraulic-Mechanical Drilling Pipe Handling System

    DEFF Research Database (Denmark)

    Choux, Martin; Blanke, Mogens

    2011-01-01

    Leakage and increased friction are common faults in hydraulic cylinders that can have serious consequences if they are not detected at early stage. In this paper, the design of a fault detector for a nonlinear hydraulic mechanical system is presented. By considering the system in steady state, two...

  2. A Fault Diagnosis Expert System for a Heavy Motor Used in a Rolling Mill

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A fault diagnosis expert system for a heavy motor used in a rolling mill is established in this paper. The fault diagnosis knowledge base was built, and its knowledge was represented by production rules. The knowledge base includes daily inspection system, brief diagnosis system and precise diagnosis system. A pull-down menu was adopted for the management of the knowledge base. The system can run under the help of expert system development tools. Practical examples show that the expert system can diagnose faults rapidly and precisely.

  3. Fault diagnosis in neutral point indirectly grounded system based on information fusion

    Institute of Scientific and Technical Information of China (English)

    于飞; 鞠丽叶; 刘喜梅; 崔平远; 钟秋海

    2003-01-01

    In neutral point indirectly grounded systems, phase-to-ground fault is putting new demands on fault diagnosis technology. Information fusion is applied to detect the phase-to-ground fault, which integrates several sources of information, including line current, line voltage, zero sequence current and voltage, and quintic harmonic wave component. This method is testified through the simulation of Matlab. Simulation results show that the precision and reliability of the detection has been greatly increased.

  4. Validation Methods for Fault-Tolerant avionics and control systems, working group meeting 1

    Science.gov (United States)

    1979-01-01

    The proceedings of the first working group meeting on validation methods for fault tolerant computer design are presented. The state of the art in fault tolerant computer validation was examined in order to provide a framework for future discussions concerning research issues for the validation of fault tolerant avionics and flight control systems. The development of positions concerning critical aspects of the validation process are given.

  5. EXFI: a low cost Fault Injection System for embedded Microprocessor-based Boards

    OpenAIRE

    Benso, Alfredo; Prinetto, Paolo Ernesto; Rebaudengo, Maurizio; Sonza Reorda, Matteo

    1998-01-01

    Evaluating the faulty behavior of low-cost embedded microprocessor-based boards is an increasingly important issue, due to their adoption in many safety critical systems. The architecture of a complete Fault Injection environment is proposed, integrating a module for generating a collapsed list of faults, and another for performing their injection and gathering the results. To address this issue, the paper describes a software-implemented Fault Injection approach based on the Trace Exception ...

  6. Tertiary sedimentation along the Lake Mead fault system, Virgin Mountains, Nevada-Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Beard, L.S. (Geological Survey, Flagstaff, AZ (United States)); Ward, S. (Northern Arizona Univ., Flagstaff, AZ (United States). Dept. of Geology)

    1993-04-01

    Sedimentary rocks of the Thumb and Rainbow Gardens Members of the Tertiary Horse Spring Formation crop out within the Virgin and South Virgin Mountains in Nevada-Arizona. The Virgins are cut by a broad zone of northeast-striking left-lateral and north-striking normal faults collectively part of the Lake Mead oblique left-lateral fault system (LMFS). Horse Spring rocks are faulted and variably eastward tilted (10--50[degree]) within the LMFS and extend northward from the Gold Butte left-lateral fault across the Lime Ridge left-lateral fault to the south flank of the Virgin Mountains. The Rainbow Gardens Member (24--18 Ma) was deposited in a shallow basin; gradual facies changes show no influence of active faulting. In contrast, lateral and vertical facies in the Thumb (16--14) Ma change abruptly and are strongly influenced by oblique-slip faulting and uplift. An unconformity separates pedogenically altered limestone of the Rainbow Gardens from overlying well-bedded lacustrine limestones of the Thumb. Locally the unconformity is overlain by conglomerate and megabreccia deposits composed of underlying Rainbow Gardens carbonate clasts derived from energy fault scarps. Thumb carbonates above the unconformity grade laterally and vertically into thick deposits of lacustrine gypsum and fine-grained sandstone, which in turn intertongue laterally and vertically with marginal lake and alluvial fan facies. Abrupt influx of megabreccia and coarse conglomerate into Thumb lacustrine deposits northward from both the Gold Butte and Lime Ridge faults indicates continued faulting.

  7. Pivotal decomposition for reliability analysis of fault tolerant control systems on unmanned aerial vehicles

    International Nuclear Information System (INIS)

    In this paper, we describe a framework to efficiently assess the reliability of fault tolerant control systems on low-cost unmanned aerial vehicles. The analysis is developed for a system consisting of a fixed number of actuators. In addition, the system includes a scheme to detect failures in individual actuators and, as a consequence, switch between different control algorithms for automatic operation of the actuators. Existing dynamic reliability analysis methods are insufficient for this class of systems because the coverage parameters for different actuator failures can be time-varying, correlated, and difficult to obtain in practice. We address these issues by combining new fault detection performance metrics with pivotal decomposition. These new metrics capture the interactions in different fault detection channels, and can be computed from stochastic models of fault detection algorithms. Our approach also decouples the high dimensional analysis problem into low dimensional sub-problems, yielding a computationally efficient analysis. Finally, we demonstrate the proposed method on a numerical example. The analysis results are also verified by Monte Carlo simulations. - Highlights: • We study fault tolerant control (FTC) systems on low-cost unmanned aerial vehicles. • We build a reliability structure model for FTC systems. • New fault detection performance metrics are integrated via pivotal decomposition. • The fault detection metrics capture the interactions in fault detection channels. • Numerical results show that FTC techniques can improve system reliability

  8. A flexible simulator for training an early fault diagnostic system

    International Nuclear Information System (INIS)

    An early fault diagnostic system has been developed addressed to timely trouble shooting in process plants during any operational modes. The theory of this diagnostic system is related with the usage of learning methods for automatic generation of knowledge bases. This approach enables the conversion of ''cause→effect'' relations into ''effect→possible-causes'' ones. The diagnostic rules are derived from the operation of a plant simulator according to a specific procedure. Flexibility, accuracy and high speed are the major characteristics of the training simulator, used to generate the diagnostic knowledge base. The simulator structure is very flexible, being based on LEGO code but allowing the use of practically any kind of FORTRAN routines (recently also ACSL macros has been introduced) as plant modules: this permits, when needed, a very accurate description of the malfunctions the diagnostic system should ''known''. The high speed is useful to shorten the ''learning'' phase of the diagnostic system. The feasibility of the overall system has been assessed, using as reference plant the conventional Sampierdarena (Italy) power station, that is a combined cycle plant dedicated to produce both electrical and heat power. The hardware configuration of this prototype system was made up of a network of a Hewlett-Packard workstation and a Digital VAX-Station. The paper illustrates the basic structure of the simulator used for this diagnostic system training purpose, as well as the theoretical background on which the diagnostic system is based. Some evidence of the effectiveness of the concept through the application to Sampierdarena 40 MW cogeneration plant is reported. Finally an outline of an ongoing application to a WWER-1000 plant is given; the operating system is, in this case, UNIX. (author)

  9. Doubly Fed Induction Generator Wind Turbine Systems Subject to Recurring Symmetrical Grid Faults

    DEFF Research Database (Denmark)

    Chen, Wenjie; Blaabjerg, Frede; Zhu, Nan; Chen, Min; Xu, Dehong

    2016-01-01

    New grid codes demand the wind turbine systems to ride through recurring grid faults. In this paper, the performance of the doubly Ffed induction generator (DFIG) wind turbine system under recurring symmetrical grid faults is analyzed. The mathematical model of the DFIG under recurring symmetrical...... grid faults is established. The analysis is based on the DFIG wind turbine system with the typical low-voltage ride-through strategy-with rotor-side crowbar. The stator natural flux produced by the voltage recovery after the first grid fault may be superposed on the stator natural flux produced by the...... model of the DFIG under recurring grid faults is verified by simulations on a 1.5-MW DFIG wind turbine system model and experiments on a 30-kW reduced scale DFIG test system....

  10. Design of a real-time fault diagnosis expert system for the EAST cryoplant

    International Nuclear Information System (INIS)

    Highlights: ► An expert system of real-time fault diagnosis for EAST cryoplant is designed. ► Knowledge base is built via fault tree analysis based on our fault experience. ► It can make up the deficiency of safety monitoring in cryogenic DCS. ► It can help operators to find the fault causes and give operation suggestion. ► It plays a role of operators training in certain degree. - Abstract: The EAST cryoplant consists of a 2 kW/4 K helium refrigerator and a helium distribution system. It is a complex process system which involves many process variables and cryogenic equipments. Each potential fault or abnormal event may influence stability and safety of the cryogenic system, thereby disturbing the fusion experiment. The cryogenic control system can monitor the process data and detect process alarms, but it is difficult to effectively diagnose the fault causes and provide operation suggestions to operators when anomalies occur. Therefore, a real-time fault diagnosis expert system is essential for a safe and steady operation of EAST cryogenic system. After a brief description of the EAST cryoplant and its control system, the structure design of the cryogenic fault diagnosis expert system is proposed. Based on the empirical knowledge, the fault diagnosis model is built adopting fault tree analysis method which considers the uncertainty. The knowledge base and the inference machine are presented in detail. A cross-platform integrated development environment Qt Creator and MySQL database have been used to develop the system. The proposed expert system has a fine graphic user interface for monitoring and operation. Preliminary test was conducted and the results found to be satisfactory.

  11. Fault Detection and Isolation of Wind Energy Conversion Systems using Recurrent Neural Networks

    Directory of Open Access Journals (Sweden)

    N. Talebi

    2014-07-01

    Full Text Available Reliability of Wind Energy Conversion Systems (WECSs is greatly important regarding to extract the maximum amount of available wind energy. In order to accurately study WECSs during occurrence of faults and to explore the impact of faults on each component of WECSs, a detailed model is required in which mechanical and electrical parts of WECSs are properly involved. In addition, a Fault Detection and Isolation System (FDIS is required by which occurred faults can be diagnosed at the appropriate time in order to ensure safe system operation and avoid heavy economic losses. This can be performed by subsequent actions through fast and accurate detection and isolation of faults. In this paper, by utilizing a comprehensive dynamic model of the WECS, an FDIS is presented using dynamic recurrent neural networks. In industrial processes, dynamic neural networks are known as a good mathematical tool for fault detection. Simulation results show that the proposed FDIS detects faults of the generator's angular velocity sensor, pitch angle sensors and pitch actuators appropriately. The suggested FDIS is capable to detect and isolate the faults shortly while owing very low false alarms rate. The presented FDIS scheme can be used to identify faults in other parts of the WECS.

  12. Fault-tolerant flight control system combining expert system and analytical redundancy concepts

    Science.gov (United States)

    Handelman, Dave

    1987-01-01

    This research involves the development of a knowledge-based fault-tolerant flight control system. A software architecture is presented that integrates quantitative analytical redundancy techniques and heuristic expert system problem solving concepts for the purpose of in-flight, real-time failure accommodation.

  13. Early Tertiary transtension-related deformation and magmatism along the Tintina fault system, Alaska

    Science.gov (United States)

    Till, A.B.; Roeske, S.M.; Bradley, D.C.; Friedman, R.; Layer, P.W.

    2007-01-01

    Transtensional deformation was concentrated in a zone adjacent to the Tintina strike-slip fault system in Alaska during the early Tertiary. The deformation occurred along the Victoria Creek fault, the trace of the Tintina system that connects it with the Kaltag fault; together the Tintina and Kaltag fault systems girdle Alaska from east to west. Over an area of ???25 by 70 km between the Victoria Creek and Tozitna faults, bimodal volcanics erupted; lacustrine and fluvial rocks were deposited; plutons were emplaced and deformed; and metamorphic rocks cooled, all at about the same time. Plutonic and volcanic rocks in this zone yield U-Pb zircon ages of ca. 60 Ma; 40Ar/ 39Ar cooling ages from those plutons and adjacent metamorphic rocks are also ca. 60 Ma. Although early Tertiary magmatism occurred over a broad area in central Alaska, meta- morphism and ductile deformation accompanied that magmatism in this one zone only. Within the zone of deformation, pluton aureoles and metamorphic rocks display consistent NE-SW-stretching lineations parallel to the Victoria Creek fault, suggesting that deformation processes involved subhorizontal elongation of the package. The most deeply buried metamorphic rocks, kyanite-bearing metapelites, occur as lenses adjacent to the fault, which cuts the crust to the Moho (Beaudoin et al., 1997). Geochronologic data and field relationships suggest that the amount of early Tertiary exhumation was greatest adjacent to the Victoria Creek fault. The early Tertiary crustal-scale events that may have operated to produce transtension in this area are (1) increased heat flux and related bimodal within-plate magmatism, (2) movement on a releasing stepover within the Tintina fault system or on a regional scale involving both the Tintina and the Kobuk fault systems, and (3) oroclinal bending of the Tintina-Kaltag fault system with counterclockwise rotation of western Alaska. ?? 2007 The Geological Society of America. All rights reserved.

  14. Research into a distributed fault diagnosis system and its application

    Science.gov (United States)

    Qian, Suxiang; Jiao, Weidong; Lou, Yongjian; Shen, Xiaomei

    2005-12-01

    CORBA (Common Object Request Broker Architecture) is a solution to distributed computing methods over heterogeneity systems, which establishes a communication protocol between distributed objects. It takes great emphasis on realizing the interoperation between distributed objects. However, only after developing some application approaches and some practical technology in monitoring and diagnosis, can the customers share the monitoring and diagnosis information, so that the purpose of realizing remote multi-expert cooperation diagnosis online can be achieved. This paper aims at building an open fault monitoring and diagnosis platform combining CORBA, Web and agent. Heterogeneity diagnosis object interoperate in independent thread through the CORBA (soft-bus), realizing sharing resource and multi-expert cooperation diagnosis online, solving the disadvantage such as lack of diagnosis knowledge, oneness of diagnosis technique and imperfectness of analysis function, so that more complicated and further diagnosis can be carried on. Take high-speed centrifugal air compressor set for example, we demonstrate a distributed diagnosis based on CORBA. It proves that we can find out more efficient approaches to settle the problems such as real-time monitoring and diagnosis on the net and the break-up of complicated tasks, inosculating CORBA, Web technique and agent frame model to carry on complemental research. In this system, Multi-diagnosis Intelligent Agent helps improve diagnosis efficiency. Besides, this system offers an open circumstances, which is easy for the diagnosis objects to upgrade and for new diagnosis server objects to join in.

  15. Remote Fault Information Acquisition and Diagnosis System of the Combine Harvester Based on LabVIEW

    Science.gov (United States)

    Chen, Jin; Wu, Pei; Xu, Kai

    Most combine harvesters have not be equipped with online fault diagnosis system. A fault information acquisition and diagnosis system of the Combine Harvester based on LabVIEW is designed, researched and developed. Using ARM development board, by collecting many sensors' signals, this system can achieve real-time measurement, collection, displaying and analysis of different parts of combine harvesters. It can also realize detection online of forward velocity, roller speed, engine temperature, etc. Meanwhile the system can judge the fault location. A new database function is added so that we can search the remedial measures to solve the faults and also we can add new faults to the database. So it is easy to take precautions against before the combine harvester breaking down then take measures to service the harvester.

  16. A Grid Voltage Measurement Method for Wind Power Systems during Grid Fault Conditions

    Directory of Open Access Journals (Sweden)

    Cheol-Hee Yoo

    2014-11-01

    Full Text Available Grid codes in many countries require low-voltage ride-through (LVRT capability to maintain power system stability and reliability during grid fault conditions. To meet the LVRT requirement, wind power systems must stay connected to the grid and also supply reactive currents to the grid to support the recovery from fault voltages. This paper presents a new fault detection method and inverter control scheme to improve the LVRT capability for full-scale permanent magnet synchronous generator (PMSG wind power systems. Fast fault detection can help the wind power systems maintain the DC-link voltage in a safe region. The proposed fault detection method is based on on-line adaptive parameter estimation. The performance of the proposed method is verified in comparison to the conventional voltage measurement method defined in the IEC 61400-21 standard.

  17. Battery System Modeling for a Military Electric Propulsion Vehicle with a Fault Simulation

    Directory of Open Access Journals (Sweden)

    Hyeongcheol Lee

    2013-10-01

    Full Text Available This paper describes the development process and results of a battery system model with a fault simulation for electric propulsion vehicles. The developed battery system model can be used to verify control and fault diagnosis strategies of the supervisory controller in an electric propulsion vehicle. To develop this battery system model, three sub-models, including a battery model, a relay assembly model, and a battery management system (BMS model, are connected together like in the target real battery system. Comparison results between the real battery system hardware and the battery system model show a similar tendency and values. Furthermore, the fault injection test of the model shows that the proposed battery system model can simulate a failure situation consistent with a real system. It is possible for the model to emulate the battery characteristics and fault situation if it is used in the development process of a BMS or for supervisory control strategies for electric propulsion systems.

  18. Fault-Tolerant Control of the Road Wheel Subsystem in a Steer-By-Wire System

    Directory of Open Access Journals (Sweden)

    Bing Zheng

    2008-01-01

    Full Text Available This paper describes a fault-tolerant steer-by-wire road wheel control system. With dual motor and dual microcontroller architecture, this system has the capability to tolerate single-point failures without degrading the control system performance. The arbitration bus, mechanical arrangement of motors, and the developed control algorithm allow the system to reconfigure itself automatically in the event of a single-point fault, and assure a smooth reconfiguration process. Both simulation and experimental results illustrate the effectiveness of the proposed fault-tolerant control system.

  19. Application of Joint Parameter Identification and State Estimation to a Fault-Tolerant Robot System

    DEFF Research Database (Denmark)

    Sun, Zhen; Yang, Zhenyu

    The joint parameter identification and state estimation technique is applied to develop a fault-tolerant space robot system. The potential faults in the considered system are abrupt parametric faults, which indicate that some system parameters will immediately deviate from their nominal values if a......, it would further simplify the reconfigurable design task and possibly speed up the system recovery, if the system state information under the new operating circumstance can be available along with faulty parameter information. The joint parameter identification and state estimation using the combined...

  20. Expert system for detecting and diagnosing car engine starter cranks fault using dynamic control system

    Directory of Open Access Journals (Sweden)

    David Ibitayo LANLEGE

    2015-12-01

    Full Text Available Application of Dynamic Control Systems (DCS in detecting and diagnosing car engine Starter Cranks is continuously being implemented to serve different cases of real life problems such as Control of MEMS-based scanning-probe data-storage devices, track-follow control for tape storage, probe-based ultrahigh-density storage technology, a review of feed forward control approaches in nanopositioning for high-speed SPM and so on. Car engine Starter Cranks faults can be detected by sequence of diagnostic processes which brings about the deployment of an Expert System. An Expert System is one of the leading Artificial Intelligence techniques that have been adopted to handle such task. This paper presents the imperatives for an Expert System in developing Dynamic Control Systems for detecting and diagnosing car engine Starter Crank faults through input and output requirements of constructing successful Knowledge-Based Systems. Furthermore, diagnosis of car engine Starter Cranks faults requires high technical skills and experience. thus, DCS provides input and output equations in form of Matrix/Vector State Space Representation (MSSR which is useful in assisting mechanics for car engine Starter Cranks fault detection and diagnosis via DCS and mathematical Differential Equations (DE’s.

  1. Minimum System Sensitivity Study of Linear Discrete Time Systems for Fault Detection

    Directory of Open Access Journals (Sweden)

    Xiaobo Li

    2013-01-01

    Full Text Available Fault detection is a critical step in the fault diagnosis of modern complex systems. An important notion in fault detection is the smallest gain of system sensitivity, denoted as ℋ− index, which measures the worst fault sensitivity. This paper is concerned with characterizing ℋ− index for linear discrete time systems. First, a necessary and sufficient condition on the lower bound of ℋ− index in finite time horizon for linear discrete time-varying systems is developed. It is characterized in terms of the existence of solution to a backward difference Riccati equation with an inequality constraint. The result is further extended to systems with unknown initial condition based on a modified ℋ− index. In addition, for linear time-invariant systems in infinite time horizon, based on the definition of the ℋ− index in frequency domain, a condition in terms of algebraic Riccati equation is developed. In comparison with the well-known bounded real lemma, it is found that ℋ− index is not completely dual to ℋ∞ norm. Finally, several numerical examples are given to illustrate the main results.

  2. 4D modelling of the Alto Tiberina Fault system (Northern Apennines, Italy)

    Science.gov (United States)

    De Donatis, Mauro; Susini, Sara; Mirabella, Francesco; Lupattelli, Andrea; Barchi, Massimiliano

    2014-05-01

    The Alto Tiberina Fault (ATF) in the Northern Apennines of Italy is a low-angle normal fault dipping to the East and accommodating up to 10 km of extension. The fault is ~70 km long and is the detachment for the SW-dipping Gubbio normal fault. The ATF fault system has been dramatically exhumed and the ATF footwall has evolved in a horst bounded to the east by ATF synthetic faults and to the west by the Corciano west-dipping normal fault. The fault has been widely studied over the last years in order to understand its mechanical behaviour, its present-day deformation rate and its seismological role. By using a wide data-set including subsurface data (seismic reflection profiles and boreholes) and surface geological data (new maps of the CARG project of Italy), we have reconstructed the 3D geometry of both the fault and of the main lithostratigraphic boundaries at the fault hanging-wall and foot-wall. The CARG map data were integrated by local observations and mapping using mobile GIS software (BeeGIS) and Android app (Geopaparazzi). Surface data were combined with seismic reflection profiles and wells interpretation and other data from available literature. The large amount of information were combined in MOVE software (Midland Valley Exploration ltd). Our reconstruction allows to i) build up a three-dimensional geological model of the subsurface including the main faults and lithostratigraphic boundaries; ii) identify a set of east-west trending faults the role of which was previously underestimated; iii) test a 3D-restoration of extension for the visualization of the time evolution and for the validation of the structural reconstruction. The restored structures are the main normal faults in the region. The sequential restoration was performed by taking into account the timing of deformation as derived from the literature. The model was sequentially restored according to the following chronological order from the latest to the oldest: 1a) last deformational event

  3. Active fault tolerant control of piecewise affine systems with reference tracking and input constraints

    DEFF Research Database (Denmark)

    Gholami, M.; Cocquempot, V.; Schiøler, H.; Bak, Thomas

    2014-01-01

    An active fault tolerant control (AFTC) method is proposed for discrete-time piecewise affine (PWA) systems. Only actuator faults are considered. The AFTC framework contains a supervisory scheme, which selects a suitable controller in a set of controllers such that the stability and an acceptable...

  4. Fault diagnostic instrumentation design for environmental control and life support systems

    Science.gov (United States)

    Yang, P. Y.; You, K. C.; Wynveen, R. A.; Powell, J. D., Jr.

    1979-01-01

    As a development phase moves toward flight hardware, the system availability becomes an important design aspect which requires high reliability and maintainability. As part of continous development efforts, a program to evaluate, design, and demonstrate advanced instrumentation fault diagnostics was successfully completed. Fault tolerance designs for reliability and other instrumenation capabilities to increase maintainability were evaluated and studied.

  5. Synthesis of Fault-Tolerant Embedded Systems with Checkpointing and Replication

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Pop, Paul; Eles, Petru; Peng, Zebo

    We present an approach to the synthesis of fault-tolerant hard real-time systems for safety-critical applications. We use checkpointing with rollback recovery and active replication for tolerating transient faults. Processes are statically scheduled and communications are performed using the time...

  6. Energy-Aware Synthesis of Fault-Tolerant Schedules for Real-Time Distributed Embedded Systems

    DEFF Research Database (Denmark)

    Poulsen, Kåre Harbo; Pop, Paul; Izosimov, Viacheslav

    This paper presents a design optimisation tool for distributed embedded real-time systems that 1) decides mapping, fault-tolerance policy and generates a fault-tolerant schedule, 2) is targeted for hard real-time, 3) has hard reliability goal, 4) generates static schedule for processes and messages...

  7. Surveillance system and method having an operating mode partitioned fault classification model

    Science.gov (United States)

    Bickford, Randall L. (Inventor)

    2005-01-01

    A system and method which partitions a parameter estimation model, a fault detection model, and a fault classification model for a process surveillance scheme into two or more coordinated submodels together providing improved diagnostic decision making for at least one determined operating mode of an asset.

  8. The Minimum Cut Sets of System Fault Based on Oriented Matrix Analysis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, the oriented matrix analysis (OMA) method of system reliability has been discussed. OMA uses a oriented fault graph instead of a traditional fault tree model. By defining the specific logic operation and calculating a reachability matrix, the cut sets can be formed directly and the minimum cut sets can be easily obtained.

  9. Development of acoustic emission monitoring system for fault detection of thermal reduction reactor

    International Nuclear Information System (INIS)

    The research on the development of the fault monitoring system for the thermal reduction reactor has been performed preliminarily in order to support the successful operation of the thermal reduction reactor. The final task of the development of the fault monitoring system is to assure the integrity of the thermal reduction reactor by the Acoustic Emission (AE) method. The objectives of this paper are to identify and characterize the fault-induced signals for the discrimination of the various AE signals acquired during the reactor operation. The AE data acquisition and analysis system was constructed and applied to the fault monitoring of the small-scale reduction reactor. Through the series of experiments, the various signals such as background noise, operating signals, and fault-induced signals were measured and their characteristics were identified, which will be used in the signal discrimination for further application to full-scale thermal reduction reactor

  10. Dynamical system analysis and forecasting of deformation produced by an earthquake fault

    CERN Document Server

    Anghel, M; Rico-Martínez, R; Rico-Martinez, Ramiro

    2003-01-01

    We present a method of constructing low-dimensional nonlinear models describing the main dynamical features of a discrete 2D cellular fault zone, with many degrees of freedom, embedded in a 3D elastic solid. A given fault system is characterized by a set of parameters that describe the dynamics, rheology, property disorder, and fault geometry. Depending on the location in the system parameter space we show that the coarse dynamics of the fault can be confined to an attractor whose dimension is significantly smaller than the space in which the dynamics takes place. Our strategy of system reduction is to search for a few coherent structures that dominate the dynamics and to capture the interaction between these coherent structures. The identification of the basic interacting structures is obtained by applying the Proper Orthogonal Decomposition (POD) to the surface deformations fields that accompany strike-slip faulting accumulated over equal time intervals. We use a feed-forward artificial neural network (ANN)...

  11. Stabiliser Fault Emergency Control using Reconfiguration to Preserve Power System Stability

    DEFF Research Database (Denmark)

    Pedersen, Andreas Søndergaard; Richter, Jan H.; Tabatabaeipour, Mojtaba;

    2014-01-01

    Stabiliser faults in multi-machine power systems are examined in this paper where fault-masking and system reconguration of the nonlinear system is obtained using a virtual actuator approach. Phasor Measurement Units, which can be integrated in wide-area transmission grids to improve the performa......Stabiliser faults in multi-machine power systems are examined in this paper where fault-masking and system reconguration of the nonlinear system is obtained using a virtual actuator approach. Phasor Measurement Units, which can be integrated in wide-area transmission grids to improve the...... performance of power system stabilisers, are utilised when reconguring remaining stabilisers after one has been inoperable by a local failure. A stabilitypreserving reconguration is designed using absolute stability results for Lure type systems: The calculation of the virtual actuator that relies on a...

  12. Fault-Tolerant Relative Navigation System (RNS) for Docking Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A method is propsed to develop a sensor fusion process for blending GPS/IMU/EO data for fault tolerant rendezvous and docking of spacecraft. The methodology takes...

  13. Actuator fault diagnosis of time-delay systems based on adaptive observer

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A novel approach for the actuator fault diagnosis of time-delay systems is presented by using an adaptive observer technique. Systems without model uncertainty are initially considered, followed by a discussion of a general situation where the system is subjected to either model uncertainty or external disturbance. An adaptive diagnostic algorithm is developed to diagnose the fault, and a modified version is proposed for general system to improve robustness. The selection of the threshold for fault detection is also discussed. Finally, a numerical example is given to illustrate the efficiency of the proposed method.

  14. Using unknown input observers for robust adaptive fault detection in vector second-order systems

    Science.gov (United States)

    Demetriou, Michael A.

    2005-03-01

    The purpose of this manuscript is to construct natural observers for vector second-order systems by utilising unknown input observer (UIO) methods. This observer is subsequently used for a robust fault detection scheme and also as an adaptive detection scheme for a certain class of actuator faults wherein the time instance and characteristics of an incipient actuator fault are detected. Stability of the adaptive scheme is provided by a parameter-dependent Lyapunov function for second-order systems. Numerical example on a mechanical system describing an automobile suspension system is used to illustrate the theoretical results.

  15. Applying Parametric Fault Detection to a Mechanical System

    DEFF Research Database (Denmark)

    Felício, P.; Stoustrup, Jakob; Niemann, H.; Lourtie, P.

    A way of doing parametric fault detection is described. It is based on the representation of parameter changes as linear fractional transformations (lfts). We describe a model with parametric uncertainty. Then a stabilizing controller is chosen and its robustness properties are studied via mu. Th...... parameter changes (faults) are estimated based on estimates of the fictitious signals that enter the delta block in the lft. These signal estimators are designed by H-infinity techniques. The chosen example is an inverted pendulum....

  16. Battery System Modeling for a Military Electric Propulsion Vehicle with a Fault Simulation

    OpenAIRE

    Hyeongcheol Lee; Kyuhong Han; Hyeongjin Ham

    2013-01-01

    This paper describes the development process and results of a battery system model with a fault simulation for electric propulsion vehicles. The developed battery system model can be used to verify control and fault diagnosis strategies of the supervisory controller in an electric propulsion vehicle. To develop this battery system model, three sub-models, including a battery model, a relay assembly model, and a battery management system (BMS) model, are connected together like in the target r...

  17. Bayesian probabilities of earthquake occurrences in Longmenshan fault system (China)

    Science.gov (United States)

    Wang, Ying; Zhang, Keyin; Gan, Qigang; Zhou, Wen; Xiong, Liang; Zhang, Shihua; Liu, Chao

    2015-01-01

    China has a long history of earthquake records, and the Longmenshan fault system (LFS) is a famous earthquake zone. We believed that the LFS could be divided into three seismogenic zones (north, central, and south zones) based on the geological structures and the earthquake catalog. We applied the Bayesian probability method using extreme-value distribution of earthquake occurrences to estimate the seismic hazard in the LFS. The seismic moment, slip rate, earthquake recurrence rate, and magnitude were considered as the basic parameters for computing the Bayesian prior estimates of the seismicity. These estimates were then updated in terms of Bayes' theorem and historical estimates of seismicity in the LFS. Generally speaking, the north zone seemingly is quite peaceful compared with the central and south zones. The central zone is the most dangerous; however, the periodicity of earthquake occurrences for M s = 8.0 is quite long (1,250 to 5,000 years). The selection of upper bound probable magnitude influences the result, and the upper bound magnitude of the south zone maybe 7.5. We obtained the empirical relationship of magnitude conversion for M s and ML, the values of the magnitude of completeness Mc (3.5), and the Gutenberg-Richter b value before applying the Bayesian extreme-value distribution of earthquake occurrences method.

  18. Online Location of Faults on AC Cables in Underground Transmission Systems

    DEFF Research Database (Denmark)

    Jensen, Christian Flytkjær

    deviations in the parameters of the OHL will result in large errors for fault location in the cable section. Field measurements showing the effect of short circuits on crossbonded systems conducted on parts of the electrical connection to the Anholt offshore wind farm are performed. The purpose is to examine...... whether neural networks can be trained using data from state-of-theart cable models to predict and estimate the fault location on crossbonded cables. Numerous measurements of different short circuits are carried out and it is concluded that the state-ofthe-art models predict general behaviour of the...... crossbonded system under fault conditions well, but the accuracy of the calculated impedance is low for fault location purposes. The neural networks can therefore not be trained and no impedance-based fault location method can be used for crossbonded cables or hybrid lines. The use of travelling wave...

  19. Robust observer-based fault estimation and accommodation of discrete-time piecewise linear systems

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Bak, Thomas

    2013-01-01

    formulated in terms of linear matrix inequalities (LMI) which can be solved efficiently. Also, performance of the estimator and the state feedback controller are minimized by solving convex optimization problems. The efficiency of the method is demonstrated by means of a numerical example....... estimate of fault is used to compensate for the effect of the fault. By using the estimate of fault and the states, a fault tolerant controller using a PWL state feedback is designed. The observer-based fault-tolerant controller is obtained by the interconnection of the estimator and the state feedback...... controller. We show that separate design of the state feedback and the estimator results in the stability of the overall closed-loop system. In addition, the input-to-state stability (ISS) gain for the closed-loop system is obtained and a procedure for minimizing it is given. All of the design conditions are...

  20. Application of a Fault Detection and Isolation System on a Rotary Machine

    Directory of Open Access Journals (Sweden)

    Silvia M. Zanoli

    2013-01-01

    Full Text Available The paper illustrates the design and the implementation of a Fault Detection and Isolation (FDI system to a rotary machine like a multishaft centrifugal compressor. A model-free approach, that is, the Principal Component Analysis (PCA, has been employed to solve the fault detection issue. For the fault isolation purpose structured residuals have been adopted while an adaptive threshold has been designed in order to detect and to isolate the faults. To prove the goodness of the proposed FDI system, historical data of a nitrogen centrifugal compressor employed in a refinery plant are considered. Tests results show that detection and isolation of single as well as multiple faults are successfully achieved.

  1. Fault tree synthesis for software design analysis of PLC based safety-critical systems

    Energy Technology Data Exchange (ETDEWEB)

    Koo, S. R.; Cho, C. H. [Corporate R and D Inst., Doosan Heavy Industries and Construction Co., Ltd., 39-3, Seongbok-Dong, Yongin-Si, Gyeonggi-Do 449-795 (Korea, Republic of); Seong, P. H. [Dept. of Nuclear and Quantum Engineering, Korea Advanced Inst. of Science and Technology, 373-3 Guseong-dong, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

    2006-07-01

    As a software verification and validation should be performed for the development of PLC based safety-critical systems, a software safety analysis is also considered in line with entire software life cycle. In this paper, we propose a technique of software safety analysis in the design phase. Among various software hazard analysis techniques, fault tree analysis is most widely used for the safety analysis of nuclear power plant systems. Fault tree analysis also has the most intuitive notation and makes both qualitative and quantitative analyses possible. To analyze the design phase more effectively, we propose a technique of fault tree synthesis, along with a universal fault tree template for the architecture modules of nuclear software. Consequently, we can analyze the safety of software on the basis of fault tree synthesis. (authors)

  2. Fault tree synthesis for software design analysis of PLC based safety-critical systems

    International Nuclear Information System (INIS)

    As a software verification and validation should be performed for the development of PLC based safety-critical systems, a software safety analysis is also considered in line with entire software life cycle. In this paper, we propose a technique of software safety analysis in the design phase. Among various software hazard analysis techniques, fault tree analysis is most widely used for the safety analysis of nuclear power plant systems. Fault tree analysis also has the most intuitive notation and makes both qualitative and quantitative analyses possible. To analyze the design phase more effectively, we propose a technique of fault tree synthesis, along with a universal fault tree template for the architecture modules of nuclear software. Consequently, we can analyze the safety of software on the basis of fault tree synthesis. (authors)

  3. Influence of growth faults on coastal fluvial systems: Examples from the late Miocene to Recent Mississippi River Delta

    Science.gov (United States)

    Armstrong, Christopher; Mohrig, David; Hess, Thomas; George, Terra; Straub, Kyle M.

    2014-03-01

    The details of how fluvial systems respond to spatial changes in land-surface subsidence produced by active faulting remain incompletely understood. Here, we examine the degree to which the positioning of individual channels and channel-belts is affected by local maxima in subsidence associated with the hanging walls of growth faults. The channel forms and faults are imaged using a seismic volume covering 1400 km2 of Breton Sound and Barataria Bay in southern Louisiana, USA. We look at the consequences of interactions between channels, channel-belts, and faults in late Miocene to Recent strata. More than fifty individual channels that crossed the traces of active growth faults were examined. Of these channels, only three appear to have been redirected by the faults. There also appeared to be no systematic change in the cross-sectional geometries of channels or channel-belts associated with crossing a fault, though the orientation of the channel-belts appears to be more influenced by faulting than the orientation of individual channels. Seven out of ten mapped channel-belts appear to have been steered by growth faults. We propose that channel belts are more likely to be influenced by faults than individual channels because channel-belts are longer lived features, unlikely to shift their overall position before experiencing a discrete faulting event. In addition, the style of influence in the few cases where an individual channel is affected by a fault is different from that of larger systems. While downstream of a fault channel-belts generally become oriented perpendicular to fault strike, the individual channels are directed along the hanging wall of the fault, running parallel to the fault trace. We relate this to the ratio of the length-scale of fault rollover relative to the channel or channel-belt width. Fluvial-fault interactions with higher values for this ratio are more likely to be carried parallel to the fault trace than systems with lower ratio values.

  4. Implementation of an Effective Fault Current Limiter for 1.5 MW DFIG in Wind Power Systems

    OpenAIRE

    Panneerselvam, M; Dr. P. Prakasam; J. K. Chithra

    2014-01-01

    With the continuous increase of power demand, the capacities of renewable energy generation systems are being expanded. With the increased penetration of wind energy as a renewable energy source, there is a need to keep wind turbines connected to the grid during grid faults. The ability of WTGS (Wind Turbine Generation System) to remain connected to the grid during faults is termed as Fault-Ride Through capability (FRT) of the system. In this paper, the use of superconducting fault current li...

  5. A Fault-Tolerant Modulation Method to Counteract the Double Open-Switch Fault in Matrix Converter Drive Systems without Redundant Power Devices

    DEFF Research Database (Denmark)

    Chen, Der-Fa; Nguyen-Duy, Khiem; Liu, Tian-Hua; Andersen, Michael A. E.

    This paper studies the double open-switch fault issue occurring within the conventional matrix converter driving a three-phase permanent-magnet synchronous motor system and proposes a fault-tolerant solution by introducing a revised modulation strategy. In this switching strategy, the rectifier...

  6. A Fault-Tolerant Modulation Method to Counteract the Double Open-Switch Fault in Matrix Converter Drive Systems without Redundant Power Devices

    DEFF Research Database (Denmark)

    Chen, Der-Fa; Nguyen-Duy, Khiem; Liu, Tian-Hua;

    2012-01-01

    This paper studies the double open-switch fault issue occurring within the conventional matrix converter driving a three-phase permanent-magnet synchronous motor system and proposes a fault-tolerant solution by introducing a revised modulation strategy. In this switching strategy, the rectifier-s...

  7. Research on Key Techniques of Condition Monitoring and Fault Diagnosing Systems of Machine Groups

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-kai; LIAO Ming-fu; WANG Si-ji

    2005-01-01

    This paper describes the development of the condition monitoring and fault diagnosing system of a group of rotating machinery. The data management is performed by means of double redundant data bases stored simultaneously in both the analyzing server and monitoring client. In this way, high reliability of the storage of data is guaranteed. Condensation of trend data releases much space resource of the hard disk. Diagnosing strategies orientated to different typical faults of rotating machinery are developed and incorporated into the system. Experimental verification shows that the system is suitable and effective for condition monitoring and fault diagnosing for a rotating machine group.

  8. Research and design of distributed intelligence fault diagnosis system in nuclear power plant

    International Nuclear Information System (INIS)

    In order to further reduce the misoperation after the faults occurring of nuclear power plant, according to the function distribution of nuclear power equipment and the distributed control features of digital instrument control system, a nuclear power plant distributed condition monitoring and fault diagnosis system was researched and designed. Based on decomposition-integrated diagnostic thinking, a fuzzy neural network and RBF neural network was presented to do the distributed local diagnosis and multi-source information fusion technology for the global integrated diagnosis. Simulation results show that the developed distributed status monitoring and fault diagnosis system can diagnose more typical accidents of PWR to provide effective diagnosis and operation information. (authors)

  9. An $H_{\\infty}$ Cooperative Fault Recovery Control of Multi-Agent Systems

    OpenAIRE

    Gallehdari, Zahra; Meskin, Nader; Khorasani, Khashayar

    2015-01-01

    In this work, an $H_{\\infty}$ performance fault recovery control problem for a team of multi-agent systems that is subject to actuator faults is studied. Our main objective is to design a distributed control reconfiguration strategy such that \\textbf{a)} in absence of disturbances the state consensus errors either remain bounded or converge to zero asymptotically, \\textbf{b)} in presence of actuator fault the output of the faulty system behaves exactly the same as that of the healthy system, ...

  10. Fault zone characteristics, fracture systems and permeability implications of Middle Triassic Muschelkalk in Southwest Germany

    Science.gov (United States)

    Meier, Silke; Bauer, Johanna F.; Philipp, Sonja L.

    2015-01-01

    Fault zone structure and lithology affect permeability of Triassic Muschelkalk limestone-marl-alternations in Southwest Germany, a region characterized by a complex tectonic history. Field studies of eight fault zones provide insights into fracture system parameters (orientation, density, aperture, connectivity, vertical extension) within fault zone units (fault core, damage zone). Results show decreasing fracture lengths with distances to the fault cores in well-developed damage zones. Fracture connectivity at fracture tips is enhanced in proximity to the slip surfaces, particularly caused by shorter fractures. Different mechanical properties of limestone and marl layers obviously affect fracture propagation and thus fracture system connectivity and permeability. Fracture apertures are largest parallel and subparallel to fault zones and prominent regional structures (e.g., Upper Rhine Graben) leading to enhanced fracture-induced permeabilities. Mineralized fractures and mineralizations in fault cores indicate past fluid flow. Permeability is increased by the development of hydraulically active pathways across several beds (non-stratabound fractures) to a higher degree than by the formation of fractures interconnected at fracture tips. We conclude that there is an increase of interconnected fractures and fracture densities in proximity to the fault cores. This is particularly clear in more homogenous rocks. The results help to better understand permeability in Muschelkalk rocks.

  11. Seismic characterization of the Wasatch fault system beneath Salt Lake City using a land streamer system

    Science.gov (United States)

    Brophy, B.; Liberty, L. M.; Gribler, G.

    2015-12-01

    We characterize the active Wasatch fault system beneath downtown Salt Lake City by measuring p- and s-wave velocities and seismic reflection profiling. Our focus was on the segment boundary between the Warm Springs and East Bench faults. We collected 14.5 km along 9 west-east profiles in 3 field days using a 60 m aperture seismic land streamer and 200 kg weight drop system. From a p-wave refraction analysis, we measure velocities from 230-3900 m/s for the upper 20-25 meters. Shear wave velocities for the upper 30 m, derived from a multi-channel analysis of surface waves (MASW) approach, show velocities that range from 100-1800 m/s. P-wave reflection images from the upper 100 m depth indicate offset and truncated (mostly) west-dipping strata (Bonneville Lake deposits?) that suggest active faults extend beneath the downtown urban corridor. We identify saturated sediments on the lower elevation (western) portions of the profiles and shallow high velocity (dry) strata to the east of the mapped faults. We observe slow p-wave velocities near identified faults that may represent the fault's colluvial wedge. These velocity results are best highlighted with Vp/Vs ratios. Analyzing shear wave velocities by NEHRP class, we estimate soft soil (NEHRP D) limited less than 1 m depth along most profiles, and stiff soil (NEHRP C) to up to 25 m depth in some locations. However near steep topographic slopes (footwall deposits), we identify NEHRP Class D stiff soil velocities to less than 2 m depth before transition to NEHRP Class C soft rock. Depth to hard rock (velocities >760 m/s) are as shallow as 20 m below the land surface on some steep slopes beneath north Salt Lake City and greater than our imaging depths along the western portions of our profiles. Our findings suggest large variations in seismic velocities beneath the Salt Lake City corridor and that multiple fault strands related to the Warm Springs fault segment extend beneath downtown.

  12. Designing Fault-Injection Experiments for the Reliability of Embedded Systems

    Science.gov (United States)

    White, Allan L.

    2012-01-01

    This paper considers the long-standing problem of conducting fault-injections experiments to establish the ultra-reliability of embedded systems. There have been extensive efforts in fault injection, and this paper offers a partial summary of the efforts, but these previous efforts have focused on realism and efficiency. Fault injections have been used to examine diagnostics and to test algorithms, but the literature does not contain any framework that says how to conduct fault-injection experiments to establish ultra-reliability. A solution to this problem integrates field-data, arguments-from-design, and fault-injection into a seamless whole. The solution in this paper is to derive a model reduction theorem for a class of semi-Markov models suitable for describing ultra-reliable embedded systems. The derivation shows that a tight upper bound on the probability of system failure can be obtained using only the means of system-recovery times, thus reducing the experimental effort to estimating a reasonable number of easily-observed parameters. The paper includes an example of a system subject to both permanent and transient faults. There is a discussion of integrating fault-injection with field-data and arguments-from-design.

  13. Real-time fault detection method based on belief rule base for aircraft navigation system

    Institute of Scientific and Technical Information of China (English)

    Zhao Xin; Wang Shicheng; Zhang Jinsheng; Fan Zhiliang; Min Haibo

    2013-01-01

    Real-time and accurate fault detection is essential to enhance the aircraft navigation system's reliability and safety.The existent detection methods based on analytical model draws back at simultaneously detecting gradual and sudden faults.On account of this reason,we propose an online detection solution based on non-analytical model.In this article,the navigation system fault detection model is established based on belief rule base (BRB),where the system measuring residual and its changing rate are used as the inputs of BRB model and the fault detection function as the output.To overcome the drawbacks of current parameter optimization algorithms for BRB and achieve online update,a parameter recursive estimation algorithm is presented for online BRB detection model based on expectation maximization (EM) algorithm.Furthermore,the proposed method is verified by navigation experiment.Experimental results show that the proposed method is able to effectively realize online parameter evaluation in navigation system fault detection model.The output of the detection model can track the fault state very well,and the faults can be diagnosed in real time and accurately.In addition,the detection ability,especially in the probability of false detection,is superior to offline optimization method,and thus the system reliability has great improvement.

  14. Hardwired interlock system with fault latchability and annunciation panel for electron accelerators

    International Nuclear Information System (INIS)

    A hard-wired interlock system is designed, developed, installed and tested to ensure healthy status for interlock signals, coming from the various sub-systems of electron accelerators as digital inputs. Each electron accelerator has approximately ninety-six interlock signals. Hardwired Interlock system consists of twelve-channel 19 inches rack mountable hard-wired interlock module of 4U height. Digital inputs are fed to the hard-wired interlock module in the form of 24V dc for logic 'TRUE' and 0V for logic 'FALSE'. These signals are flow signals to ensure cooling of the various sub-systems, signals from the klystron modulator system in RF Linac to ensure its healthy state to start, signals from high voltage system of DC accelerator, vacuum signals from vacuum system to ensure proper vacuum in the electron accelerator, door interlock signals, air flow signals, and area search and secure signals. This hard-wired interlock system ensures the safe start-up, fault annunciation and alarm, fault latchablity, and fail-safe operation of the electron accelerators. Safe start-up feature ensures that beam generation system can be made ON only when cooling of all the electron accelerator sub-systems are confirmed, all the fault signals of high voltage generation system are attended, proper vacuum is achieved inside the beam transport system, all the doors are closed and various areas have been searched and secured manually. Fault annunciation and alarm feature ensures that during the start up and operation of the electron accelerators, if any fault is there, that fault signal window keeps on flashing with red colour and alarm is sounded till the operator acknowledges the fault. Once acknowledged, flashing and alarm stops but display of the window in red colour remains till the operator clears the fault. Fault latchability feature ensures that if any fault has happened, accelerator cannot be started again till the operator resets that interlock signal. Fail-safe feature ensures

  15. Fault Ride-Through Capability of DSTATCOM for Distributed Wind Generation System

    OpenAIRE

    Manju Aggarwal; Madhusudan Singh; Gupta, S K

    2015-01-01

    In this paper, fault ride through analysis of a low voltage distribution system augmented with distributed wind generation using squirrel cage induction generator and distribution static compensator (DSTATCOM) is carried out through modeling and simulation study in MATLAB. The impact of different types of unbalanced (single line to ground) fault in a low voltage distribution system in normal and severe conditions are studied and analysed in details. Analysis on system instability is also show...

  16. Study on Fault and Isolated Condition in Two Circuit Configurations of PV-ESS Hybrid System

    OpenAIRE

    Myo Htaik; Ryoichi Hara; Hiroyuki Kita

    2012-01-01

    Most photovoltaic (PV) generation systems are connected with a utility grid and recognized as supplemental generation resources; but in some applications such as microgrid concept, a PV system works as a main resource. To improve the availability of PV systems, technological development for higher less output fluctuation in normal condition, higher fault tolerance in fault occurrence, and power demand and supply balancing in isolated condition are required. For these reasons, hybridization of...

  17. Consideration of Gyroscopic Effect in Fault Detection and Isolation for Unbalance Excited Rotor Systems

    OpenAIRE

    Zhentao Wang; Arne Wahrburg; Stephan Rinderknecht

    2012-01-01

    Fault detection and isolation (FDI) in rotor systems often faces the problem that the system dynamics is dependent on the rotor rotary frequency because of the gyroscopic effect. In unbalance excited rotor systems, the continuously distributed unbalances are hard to be determined or estimated accurately. The unbalance forces as disturbances make fault detection more complicated. The aim of this paper is to develop linear time invariant (LTI) FDI methods (i.e., with constant parameters) for ro...

  18. Steady Fault Characteristic Analysis of a Missile Power System Based on a Differential Evolution Algorithm

    Institute of Scientific and Technical Information of China (English)

    XU Zhi-gao; GUAN Zheng-xi; MA Jing

    2005-01-01

    The differential evolution (DE) algorithm is applied to solving the models' equations of a whole missile power system, and the steady fault characteristics of the whole system are analyzed. The DE algorithm is robust, requires few control variables, is easy to use and lends itself very well to parallel computation. Calculation results indicate that the DE algorithm simulates faults of a missile power system very well.

  19. Impact of MV Ground Fault Current Distribution on Global Earthing Systems

    OpenAIRE

    Tommasini, Riccardo; Napoli, Roberto; Pons, Enrico; Colella, Pietro

    2015-01-01

    Global earthing systems (GESs), created by the interconnection of local earthing systems, should guarantee the absence of dangerous touch voltages. One of the reasons for this safety characteristic of GESs is the fault current distribution between grounding electrodes and medium-voltage (MV) cable sheaths: Only a small portion of the fault current is injected into the ground by the ground grid of the faulty substation. In systems with isolated neutral or with resonant earthing, this effect ma...

  20. Development of monitoring and automatic fault detection solutions for grid-connected photovoltaic systems

    OpenAIRE

    Capogna, Vicenzo

    2012-01-01

    In this Final Thesis work, the development of a new monitoring and automatic fault detection system for grid-connected photovoltaic systems is presented and described in its details. This product has been developed in JavaScript and HTLM protocols and it allow real time an online performance monitoring and comparison together with fault detection and causes diagnosis. The presented solution is focus on the DC side of the PV system and it includes: a simple and effective simulat...

  1. A Fault Diagnosis Mechanism for a Proactive Maintenance Scheme for Wireless Systems

    OpenAIRE

    Walsh, Barbara; Farrell, Ronan

    2008-01-01

    This paper presents the fault diagnosis mechanism for a proactive maintenance scheme for wireless systems which is aimed at reducing the high operational costs encountered in the wireless industry by decreasing maintenance costs and system downtime. An on-line monitoring system, based on the aforementioned fault diagnosis mechanism, is used to identify performance degradation, as well as its possible sources, so as to ensure that maintenance occurs only when necessary.

  2. RECENT GEODYNAMICS OF FAULT ZONES: FAULTING IN REAL TIME SCALE

    Directory of Open Access Journals (Sweden)

    Yu. O. Kuzmin

    2015-09-01

    Full Text Available Recent deformation processes taking place in real time are analyzed on the basis of data on fault zones which were collected by long-term detailed geodetic survey studies with application of field methods and satellite monitoring.A new category of recent crustal movements is described and termed as parametrically induced tectonic strain in fault zones. It is shown that in the fault zones located in seismically active and aseismic regions, super intensive displacements of the crust (5 to 7 cm per year, i.e. (5 to 7·10–5 per year occur due to very small external impacts of natural or technogenic / industrial origin.The spatial discreteness of anomalous deformation processes is established along the strike of the regional Rechitsky fault in the Pripyat basin. It is concluded that recent anomalous activity of the fault zones needs to be taken into account in defining regional regularities of geodynamic processes on the basis of real-time measurements.The paper presents results of analyses of data collected by long-term (20 to 50 years geodetic surveys in highly seismically active regions of Kopetdag, Kamchatka and California. It is evidenced by instrumental geodetic measurements of recent vertical and horizontal displacements in fault zones that deformations are ‘paradoxically’ deviating from the inherited movements of the past geological periods.In terms of the recent geodynamics, the ‘paradoxes’ of high and low strain velocities are related to a reliable empirical fact of the presence of extremely high local velocities of deformations in the fault zones (about 10–5 per year and above, which take place at the background of slow regional deformations which velocities are lower by the order of 2 to 3. Very low average annual velocities of horizontal deformation are recorded in the seismic regions of Kopetdag and Kamchatka and in the San Andreas fault zone; they amount to only 3 to 5 amplitudes of the earth tidal deformations per year.A ‘fault

  3. Surface deformation along the Carmel Fault System, Israel

    Science.gov (United States)

    Reinking, Joerg; Smit-Philipp, Hillrich; Even-Tzur, Gilad

    2011-10-01

    The existing knowledge about the recent crustal deformations along the Carmel Fault in Northern Israel which passes the city of Haifa is to a certain degree ambiguous. Depending on geological, geophysical or geodetic sources the movement rates and senses range from 1 mm/yr sinistral up to 4 mm/yr dextral. In this paper we analyze GPS data from a regional network observed between 1999 and 2009 and derive global and regional velocities for 23 sites along the fault. The regional site velocities were estimated with respect to a local datum that was defined by a stable cluster of sites on one side of the fault and the horizontal velocity field shows deformations of up to 4.5 mm/yr dextral. In combination with an S-transformation the site velocities were used to estimate the parameters of a dislocation model based on elastic half space theory. We compare the results with expectations from slip rate analysis of seismicity parameters. In addition the resulting fault slip field is used to derive a fault-related velocity field.

  4. A Dynamic Finite Element Method for Simulating the Physics of Faults Systems

    Science.gov (United States)

    Saez, E.; Mora, P.; Gross, L.; Weatherley, D.

    2004-12-01

    We introduce a dynamic Finite Element method using a novel high level scripting language to describe the physical equations, boundary conditions and time integration scheme. The library we use is the parallel Finley library: a finite element kernel library, designed for solving large-scale problems. It is incorporated as a differential equation solver into a more general library called escript, based on the scripting language Python. This library has been developed to facilitate the rapid development of 3D parallel codes, and is optimised for the Australian Computational Earth Systems Simulator Major National Research Facility (ACcESS MNRF) supercomputer, a 208 processor SGI Altix with a peak performance of 1.1 TFlops. Using the scripting approach we obtain a parallel FE code able to take advantage of the computational efficiency of the Altix 3700. We consider faults as material discontinuities (the displacement, velocity, and acceleration fields are discontinuous at the fault), with elastic behavior. The stress continuity at the fault is achieved naturally through the expression of the fault interactions in the weak formulation. The elasticity problem is solved explicitly in time, using the Saint Verlat scheme. Finally, we specify a suitable frictional constitutive relation and numerical scheme to simulate fault behaviour. Our model is based on previous work on modelling fault friction and multi-fault systems using lattice solid-like models. We adapt the 2D model for simulating the dynamics of parallel fault systems described to the Finite-Element method. The approach uses a frictional relation along faults that is slip and slip-rate dependent, and the numerical integration approach introduced by Mora and Place in the lattice solid model. In order to illustrate the new Finite Element model, single and multi-fault simulation examples are presented.

  5. Study and Design of Diaphragm Pump Vibration Detection Fault Diagnosis System Based on FFT

    Directory of Open Access Journals (Sweden)

    Jia Yin

    2013-02-01

    Full Text Available This study has proposed a fault diagnosis system based on vibration detection. The system mainly includes four modules: signal acquisition module, signal processing module, state identification module, fault diagnosis and alarm module. The system uses CMSS 2200 acceleration sensor to collect vibration signals, processing spectrum with FFT (Fast Fourier Transform which is used effectively in current industry and finally achieve fault diagnosis and prediction for diaphragm pump. Through collection and analysis of the history signal data, set threshold value in the fault diagnosis system. According to the characteristics of different types, set the corresponding effective threshold value. The simulation results show that, the spectrum after FFT transformation processing, can really and effectively reflect equipment operating condition of the diaphragm. This system is not only simple and stable, but also can predict pump failure effectively, so that it reduces equipment downtime, plan maintenance time and unplanned maintenance time.

  6. Takagi Sugeno fuzzy expert model based soft fault diagnosis for two tank interacting system

    Directory of Open Access Journals (Sweden)

    Manikandan Pandiyan

    2014-09-01

    Full Text Available The inherent characteristics of fuzzy logic theory make it suitable for fault detection and diagnosis (FDI. Fault detection can benefit from nonlinear fuzzy modeling and fault diagnosis can profit from a transparent reasoning system, which can embed operator experience, but also learn from experimental and/or simulation data. Thus, fuzzy logic-based diagnostic is advantageous since it allows the incorporation of a-priori knowledge and lets the user understand the inference of the system. In this paper, the successful use of a fuzzy FDI based system, based on dynamic fuzzy models for fault detection and diagnosis of an industrial two tank system is presented. The plant data is used for the design and validation of the fuzzy FDI system. The validation results show the effectiveness of this approach.

  7. Application of Fault Location Mode Based on Travelling Waves for Neutral Non-effective Grounding Systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>Fault location for distribution feeders short circuit especially single-phase grounding fault is an important task in distribution system with non-effectively grounded neutral.Fault location mode for distribution feeders using fault generated current and voltage transient traveling waves was investigated.The characteristics of transient traveling waves resulted from each short circuit fault and their transmission disciplinarian in distribution feeders are analyzed.This paper proposed that double end travelling waves theory which measures arriving time of fault initiated surge at both ends of the monitored line is fit for distribution feeders but single end traveling waves theory not.According to different distribution feeders,on the basis of analyzing original traveling waves reflection rule in line terminal, Current-voltage mode,voltage-voltage mode and current-current mode for fault location based on traveling waves are proposed and aerial mode component of original traveling waves is used to realize fault location.Experimental test verify the feasibility and correctness of the proposed method.

  8. Constitution and application of reactor make-up system's fault diagnostic Bayesian networks

    International Nuclear Information System (INIS)

    A fault diagnostic Bayesian network of reactor make-up system was constituted. The system's structure characters, operation rules and experts' experience were combined and an initial net was built. As the fault date sets were learned with the particle swarm optimization based Bayesian network structure, the structure of diagnostic net was completed and used to inference case. The built net can analyze diagnostic probability of every node in the net and afford assistant decision to fault diagnosis. (authors)

  9. Benchmarking of Grid Fault Modes in Single-Phase Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2013-01-01

    capability. The control methods, together with grid synchronization techniques, are responsible for the generation of appropriate reference signals in order to handle ride-through grid faults. Thus, it is necessary to evaluate the behaviors of grid synchronization methods and control possibilities in single...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant synchronization and control strategies are discussed. Some faulty modes are studied experimentally...

  10. Benchmarking of grid fault modes in single-phase grid-connected photovoltaic systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    capability. The control methods, together with grid synchronization techniques, are responsible for the generation of appropriate reference signals in order to handle ride-through grid faults. Thus, it is necessary to evaluate the behaviors of grid synchronization methods and control possibilities in single...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant detection and control strategies are discussed. Some faulty modes are studied experimentally and...

  11. Fault-tolerant for Electric Vehicles Drive System Sensor Failure

    Directory of Open Access Journals (Sweden)

    Zhang Liwei

    2013-10-01

    Full Text Available When EV failure happens, it needs to take some fault-tolerant method to ensure people’s safety. When the current sensor and speed sensor are out of work, the software fault-tolerant control algorithm switching strategy can be used. This paper has done theoretical analysis of the rotor field-oriented vectoe control algorithm into the open loop constant V/F control algorithm, and the phase angle compensation method is used to reduce the shock of current and torque, and simulation is done in MATLAB/Simulink.    

  12. A Game-Theoretic approach to Fault Diagnosis of Hybrid Systems

    Directory of Open Access Journals (Sweden)

    Davide Bresolin

    2011-06-01

    Full Text Available Physical systems can fail. For this reason the problem of identifying and reacting to faults has received a large attention in the control and computer science communities. In this paper we study the fault diagnosis problem for hybrid systems from a game-theoretical point of view. A hybrid system is a system mixing continuous and discrete behaviours that cannot be faithfully modeled neither by using a formalism with continuous dynamics only nor by a formalism including only discrete dynamics. We use the well known framework of hybrid automata for modeling hybrid systems, and we define a Fault Diagnosis Game on them, using two players: the environment and the diagnoser. The environment controls the evolution of the system and chooses whether and when a fault occurs. The diagnoser observes the external behaviour of the system and announces whether a fault has occurred or not. Existence of a winning strategy for the diagnoser implies that faults can be detected correctly, while computing such a winning strategy corresponds to implement a diagnoser for the system. We will show how to determine the existence of a winning strategy, and how to compute it, for some decidable classes of hybrid automata like o-minimal hybrid automata.

  13. A Systematic Approach to Sensitivity Analysis of Fault Tolerant Systems in NMR Architecture

    Directory of Open Access Journals (Sweden)

    Kourosh Aslansefat

    2015-01-01

    Full Text Available A fault tree illustrates the ways through which a system fails. It states different ways in which combination of faulty components result in an undesired event in the system. Being used in phases such as designing and exploiting industrial systems, and the designers able to evaluate the dependability attributes such as reliability, MTTF and sensitivity. In addition, in the mentioned ability, the fault tree is a systematic method for finding systems bottlenecks and weakness point. In spite of its extensive use in evaluating the reliability of systems, fault tree is rarely used in calculating sensitivity. In the last decade, few researches has been conducted in this field, however these methods are not applicable to large scale systems and are not systematic. This paper provides a systematic method for evaluating system sensitivity through fault tree. Then, it introduces sensitivity of NMR architecture as one of the common structures of fault tolerance which is used for enhancing systems’ reliability, safety and availability in industry. This article presents a comprehensive and parameterized formula for NMR structure's sensitivity. The presented method can be a great help for designing and exploiting reliable systems engineers in systematic and instant calculation of sensitivity by means of fault tree.

  14. Qualitative Fault Isolation of Hybrid Systems: A Structural Model Decomposition-Based Approach

    Science.gov (United States)

    Bregon, Anibal; Daigle, Matthew; Roychoudhury, Indranil

    2016-01-01

    Quick and robust fault diagnosis is critical to ensuring safe operation of complex engineering systems. A large number of techniques are available to provide fault diagnosis in systems with continuous dynamics. However, many systems in aerospace and industrial environments are best represented as hybrid systems that consist of discrete behavioral modes, each with its own continuous dynamics. These hybrid dynamics make the on-line fault diagnosis task computationally more complex due to the large number of possible system modes and the existence of autonomous mode transitions. This paper presents a qualitative fault isolation framework for hybrid systems based on structural model decomposition. The fault isolation is performed by analyzing the qualitative information of the residual deviations. However, in hybrid systems this process becomes complex due to possible existence of observation delays, which can cause observed deviations to be inconsistent with the expected deviations for the current mode in the system. The great advantage of structural model decomposition is that (i) it allows to design residuals that respond to only a subset of the faults, and (ii) every time a mode change occurs, only a subset of the residuals will need to be reconfigured, thus reducing the complexity of the reasoning process for isolation purposes. To demonstrate and test the validity of our approach, we use an electric circuit simulation as the case study.

  15. The Fault Location Method Research of Three-Layer Network System

    Directory of Open Access Journals (Sweden)

    Hu Shaolin

    2012-09-01

    Full Text Available The fault location technology research of three-layer network system structure dynamic has important theoretic value and apparent engineering application value on exploring the fault detection and localization of the complex structure dynamic system. In this article, the method of failure propagation and adverse inference are adopted, the fault location algorithm of the three-layer structure dynamic network system is established on the basis of the concept of association matrix and the calculating method are proposed, and the simulation calculation confirmed the reliability of this paper. The results of the research can be used for the fault diagnosis of the hierarchical control system?testing of the engineering software and the analysis of the failure effects of layered network of all kinds and other different fields.

  16. Model-based fault detection for generator cooling system in wind turbines using SCADA data

    DEFF Research Database (Denmark)

    Borchersen, Anders Bech; Kinnaert, Michel

    2016-01-01

    In this work, an early fault detection system for the generator cooling of wind turbines is presented and tested. It relies on a hybrid model of the cooling system. The parameters of the generator model are estimated by an extended Kalman filter. The estimated parameters are then processed by an...... appropriate statistical change detection algorithm in order to detect faults in the cooling system. To validate the method, it has been tested on 3 years of historical data from 43 turbines. During the testing period, 16 faults occurred; 15 of these were detected by the developed method, and one false alarm...... was issued. This is an improvement compared with the current system that gives 15 detections and more than 10 false alarms. In some cases, the method detects the fault a long time before the turbine reports an alarm. A further advantage of the method is that it is based on supervisory control and data...

  17. Fault-Tolerant Consensus of Multi-Agent System With Distributed Adaptive Protocol.

    Science.gov (United States)

    Chen, Shun; Ho, Daniel W C; Li, Lulu; Liu, Ming

    2015-10-01

    In this paper, fault-tolerant consensus in multi-agent system using distributed adaptive protocol is investigated. Firstly, distributed adaptive online updating strategies for some parameters are proposed based on local information of the network structure. Then, under the online updating parameters, a distributed adaptive protocol is developed to compensate the fault effects and the uncertainty effects in the leaderless multi-agent system. Based on the local state information of neighboring agents, a distributed updating protocol gain is developed which leads to a fully distributed continuous adaptive fault-tolerant consensus protocol design for the leaderless multi-agent system. Furthermore, a distributed fault-tolerant leader-follower consensus protocol for multi-agent system is constructed by the proposed adaptive method. Finally, a simulation example is given to illustrate the effectiveness of the theoretical analysis. PMID:25415998

  18. Considerations for transient stability, fault capacity and power flow study of offsite power system

    International Nuclear Information System (INIS)

    By study of power flow calculation, fault capacity calculation and stability analysis according to connection of two units YGN 3 and 4 to KEPCO power system, we have conclusions as follows. As the result of power flow calculation, at peak load, the voltage change of each bus is very small when YGN 3 and 4 is connected with KEPCO power system. At base load, installation of phase modifing equipment is necessary in Seoul, Kyungki province where load is concentrated because bus voltage rises by increasing of charge capacity caused installation of underground cables. As the result of fault capacity calculation, fault capacity is increased because fault current increases when two units YGN 3 and 4 is connected with KEPCO power system. But it is enough to operate with presenting circuits breaker rated capacity. Transient stability studies have been conducted on the YK N/P generators 3 and 4 using a digital computer program. Three phase short faults have been simulated at the YK N/P 345[KV] bus with the resulting outage of transmission circuits. Several fault clearing times are applied: 6 cycles, 12 cycles, 15 cycles. The study results demonstrate that the transient stability of YK N/P is adequate to maintain stable for three phase short faults cleared within 12 cycles. The study results also demonstrate that the transient stability of YK N/P is stable for machine removals except 4-machine removal. In addition, the study shows that the transient stability analysis is implemented for the case of load

  19. Robust fault detection of wind energy conversion systems based on dynamic neural networks.

    Science.gov (United States)

    Talebi, Nasser; Sadrnia, Mohammad Ali; Darabi, Ahmad

    2014-01-01

    Occurrence of faults in wind energy conversion systems (WECSs) is inevitable. In order to detect the occurred faults at the appropriate time, avoid heavy economic losses, ensure safe system operation, prevent damage to adjacent relevant systems, and facilitate timely repair of failed components; a fault detection system (FDS) is required. Recurrent neural networks (RNNs) have gained a noticeable position in FDSs and they have been widely used for modeling of complex dynamical systems. One method for designing an FDS is to prepare a dynamic neural model emulating the normal system behavior. By comparing the outputs of the real system and neural model, incidence of the faults can be identified. In this paper, by utilizing a comprehensive dynamic model which contains both mechanical and electrical components of the WECS, an FDS is suggested using dynamic RNNs. The presented FDS detects faults of the generator's angular velocity sensor, pitch angle sensors, and pitch actuators. Robustness of the FDS is achieved by employing an adaptive threshold. Simulation results show that the proposed scheme is capable to detect the faults shortly and it has very low false and missed alarms rate. PMID:24744774

  20. A Delay System Approach to Fault Detection Filter of Networked Control Systems

    Institute of Scientific and Technical Information of China (English)

    MA Li-wei; TIAN Zuo-hua; SHI Song-jiao; WENG Zheng-xin

    2009-01-01

    In this paper, the fault detection filter (FDF) design problem for networked control systems (NCSs) with both network-induced delay and data dropout is studied. Based on a new NCSs model proposed recently, an observer-based filter is introduced to be the residual generator and formulated as an H∞-optimization problem for systems with two successive delay components. By applying Lyapunov-Krasovskii approach, a new sufficient condition on stability and H∞ performance is derived for systems with two successive delay components in the state. A solution of the optimization problem is then presented in terms of linear matrix inequality (LMI) formulation, dependently of time delay. In order to detect the fault, the residual evaluation problem is also considered. An illustrative design example is employed to demonstrate the validity of the proposed approach.

  1. Distribution, migration and derivation of Mesozoic-Cenozoic regional fault systems in the central continental margin of eastern China

    Institute of Scientific and Technical Information of China (English)

    SUN Xiaomeng; HAO Fujiang; BIAN Weihua; GAO Yi; BAO Yafan

    2007-01-01

    Deep-large faults in the central continental margin of eastern China are well developed. Based on the regularity of spatial and temporal distribution of the faults,four fault systems were divided: the Yanshan orogenic belt fault system, the Qinling-Dabie-Sulu orogenic belt fault system, the Tanlu fault system and the East China Sea shelfbasin-Okinawa trough fault system. The four fault systems exhibit different migration behaviors. The Yanshan orogenic belt fault system deflected from an EW to a NE direction,then to a NNE direction during the Indo-Chinese epoch-Yanshanian epoch. The thrust-nappe strength of the Qinling-Dabie orogenic belt fault system showed the tendency that the strength was greater in the south and east, but weaker in the north and west. This fault system faulted in the east and folded in the west from the Indo-Chinese epoch to the early Yanshanian epoch. At the same time, the faults also had a diachronous migration from east to west from the Indo-Chinese epoch to the early Yanshanian epoch. On the con-trary, the thrust-nappe strength was greater in the north and west, weaker in the south and east during the late Yanshanian epoch-early Himalayan epoch. The Tanlu fault system caused the basin to migrate from west to east and south to north. The migration regularity of the East China Sea shelf basin-Okinawa trough fault system shows that the for mation age became younger in the west. The four fault systems and their migration regularities were respectively the results of four different geodynamic backgrounds. The Yanshan orogenicbelt fault system derived from the intracontinental orogeny.The Qinling-Dabie-Sulu orogenic belt fault system derived from the collision of plates and intracontinental subduction.The Tanlu fault system derived from the strike-slip movement and the East China Sea shelf basin-Okinawa trough fault system derived from plate subduction and retreat of the subduction belt.

  2. Outline of a fault diagnosis system for a large-scale board machine

    OpenAIRE

    Jämsä-Jounela, Sirkka-Liisa; Tikkala, Vesa-Matti; Zakharov, Alexey; Pozo Garcia, Octavio; Laavi, Helena; Myller, Tommi; Kulomaa, Tomi; Hämäläinen, Veikko

    2013-01-01

    Global competition forces process industries to continuously optimize plant operation. One of the latest trends for efficiency and plant availability improvement is to set up fault diagnosis and maintenance systems for online industrial use. This paper presents a methodology for developing industrial fault detection and diagnosis (FDD) systems. Since model or data-based diagnosis of all components cannot be achieved online on a large-scale basis, the focus must be narrowed down to the most li...

  3. Preface of the special issue on Advances in Control and Fault-Tolerant Systems

    OpenAIRE

    Korbicz, Jozef; Maquin, Didier; THEILLIOL, DIDIER

    2012-01-01

    Today's automatic control systems are of high degrees of integration, complexity, embedding and networking of heterogeneous entities. This trend is driven by the industrial needs for achieving new technical performance and meeting additional performance demands. A most critical and important issue surrounding the design and operation of complex automatic systems is the application of Fault Detection and Isolation and Fault-Tolerant Control (FDI/FTC) technology, aiming at guaranteeing high sys...

  4. Computationally efficient and numerically stable reliability bounds for repairable fault-tolerant systems

    OpenAIRE

    Carrasco, Juan A.

    2002-01-01

    The transient analysis of large continuous time Markov reliability models of repairable fault-tolerant systems is computationally expensive due to model stiffness. In this paper, we develop and analyze a method to compute bounds for a measure defined on a particular, but quite wide, class of continuous time Markov models, encompassing both exact and bounding continuous time Markov unreliability models of fault-tolerant systems. The method is numerically stable and computes the bounds with wel...

  5. Krein Space-Based H∞ Fault Estimation for Discrete Time-Delay Systems

    OpenAIRE

    Xinmin Song; Xuehua Yan

    2014-01-01

    This paper investigates the finite-time ${H}_{\\infty }$ fault estimation problem for linear time-delay systems, where the delay appears in both state and measurement equations. Firstly, the design of finite horizon ${H}_{\\infty }$ fault estimation is converted into a minimum problem of certain quadratic form. Then we introduce a stochastic system in Krein space, and a sufficient and necessary condition for the minimum is derived by applying innovation analysis approach and projection theory. ...

  6. Fault Ride-Through Capability of DSTATCOM for Distributed Wind Generation System

    Directory of Open Access Journals (Sweden)

    Manju Aggarwal

    2015-06-01

    Full Text Available In this paper, fault ride through analysis of a low voltage distribution system augmented with distributed wind generation using squirrel cage induction generator and distribution static compensator (DSTATCOM is carried out through modeling and simulation study in MATLAB. The impact of different types of unbalanced (single line to ground fault in a low voltage distribution system in normal and severe conditions are studied and analysed in details. Analysis on system instability is also shown in case of sever fault condition. A distribution Static Compensator (DSTATCOM is used to improve fault ride through (FRT capability of wind generation system by compensating positive sequence voltage. A comparison of dynamic response of the system with and without DSTATCOM and effects of DSTATCOM on voltage and generator speed are presented. The simulation results shows that DSTATCOM is capable of reducing the voltage dips and improving the voltage profiles by providing reactive power support to distributed wind generation system under balanced as well as unbalanced faults condition and enhances the fault ride through capability of the wind generator

  7. Automated Generation of Fault Management Artifacts from a Simple System Model

    Science.gov (United States)

    Kennedy, Andrew K.; Day, John C.

    2013-01-01

    Our understanding of off-nominal behavior - failure modes and fault propagation - in complex systems is often based purely on engineering intuition; specific cases are assessed in an ad hoc fashion as a (fallible) fault management engineer sees fit. This work is an attempt to provide a more rigorous approach to this understanding and assessment by automating the creation of a fault management artifact, the Failure Modes and Effects Analysis (FMEA) through querying a representation of the system in a SysML model. This work builds off the previous development of an off-nominal behavior model for the upcoming Soil Moisture Active-Passive (SMAP) mission at the Jet Propulsion Laboratory. We further developed the previous system model to more fully incorporate the ideas of State Analysis, and it was restructured in an organizational hierarchy that models the system as layers of control systems while also incorporating the concept of "design authority". We present software that was developed to traverse the elements and relationships in this model to automatically construct an FMEA spreadsheet. We further discuss extending this model to automatically generate other typical fault management artifacts, such as Fault Trees, to efficiently portray system behavior, and depend less on the intuition of fault management engineers to ensure complete examination of off-nominal behavior.

  8. Evaluation of digital fault-tolerant architectures for nuclear power plant control systems

    International Nuclear Information System (INIS)

    This paper reports on four fault-tolerant architectures that were evaluated for their potential reliability in service as control systems of nuclear power plants. The reliability analyses showed that human- and software-related common cause failures and single points of failure in the output modules are dominant contributors to system unreliability. The four architectures are triple-modular-redundant, both synchronous and asynchronous, and also dual synchronous and asynchronous. The evaluation includes a review of design features, an analysis of the importance of coverage, and reliability analyses of fault-tolerant systems. Reliability analyses based on data from several industries that have fault-tolerant controllers were used to estimate the mean-time-between-failures of fault-tolerant controllers and to predict those failure modes that may be important in nuclear power plants

  9. Field Guide for Testing Existing Photovoltaic Systems for Ground Faults and Installing Equipment to Mitigate Fire Hazards: November 2012 - October 2013

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, W.

    2015-02-01

    Ground faults and arc faults are the two most common reasons for fires in photovoltaic (PV) arrays and methods exist that can mitigate the hazards. This report provides field procedures for testing PV arrays for ground faults, and for implementing high resolution ground fault and arc fault detectors in existing and new PV system designs.

  10. STUDY ON NATURAL LANGUAGE INTERFACE OF NETWORK FAULT DIAGNOSIS EXPERT SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Liu Peiqi; Li Zengzhi; Zhao Yinliang

    2006-01-01

    The expert system is an important field of the artificial intelligence. The traditional interface of the expert system is the command, menu and window at present. It limits the application of the expert system and embarrasses the enthusiasm of using expert system. Combining with the study on the expert system of network fault diagnosis, the natural language interface of the expert system has been discussed in this article. This interface can understand and generate Chinese sentences. Using this interface, the user and field experts can use the expert system to diagnose the fault of network conveniently. In the article, first, the extended production rule has been proposed. Then the methods of Chinese sentence generation from conceptual graphs and the model of expert system are introduced in detail. Using this model, the network fault diagnosis expert system and its natural language interface have been developed with Prolog.

  11. New fault location system for power transmission lines using composite fiber-optic overhead ground wire (OPGW)

    Energy Technology Data Exchange (ETDEWEB)

    Urasawa, K. (Tokyo Electric Power Co., Inc. (Japan)); Kanemaru, K.; Toyota, S.; Sugiyama, K. (Hitachi Cable, Ltd., Tokyo (Japan))

    1989-10-01

    A new fault location (FL) method using composite fiber-optic overhead ground wires (OPGWs) is developed to find out where electrical faults occur on overhead power transmission lines. This method locates the fault section by detecting the current induced in the ground wire (GW), i.e. OPGW in this system. Since detected fault information is essentially uncertain, the new FL method treats the fault information oas a current distribution pattern throughout the power line, and applies Fuzzy Theory to realize the human-like manner of fault location used by electrical power engineers. It was confirmed by computer simulations that the fault section can be accurately located using this method under various conditions. This FL system has already been applied to several commercial power transmission lines and successfully located the sections where electrical faults occurred on actual power transmission lines.

  12. A new and accurate fault location algorithm for combined transmission lines using Adaptive Network-Based Fuzzy Inference System

    Energy Technology Data Exchange (ETDEWEB)

    Sadeh, Javad; Afradi, Hamid [Electrical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, P.O. Box: 91775-1111, Mashhad (Iran)

    2009-11-15

    This paper presents a new and accurate algorithm for locating faults in a combined overhead transmission line with underground power cable using Adaptive Network-Based Fuzzy Inference System (ANFIS). The proposed method uses 10 ANFIS networks and consists of 3 stages, including fault type classification, faulty section detection and exact fault location. In the first part, an ANFIS is used to determine the fault type, applying four inputs, i.e., fundamental component of three phase currents and zero sequence current. Another ANFIS network is used to detect the faulty section, whether the fault is on the overhead line or on the underground cable. Other eight ANFIS networks are utilized to pinpoint the faults (two for each fault type). Four inputs, i.e., the dc component of the current, fundamental frequency of the voltage and current and the angle between them, are used to train the neuro-fuzzy inference systems in order to accurately locate the faults on each part of the combined line. The proposed method is evaluated under different fault conditions such as different fault locations, different fault inception angles and different fault resistances. Simulation results confirm that the proposed method can be used as an efficient means for accurate fault location on the combined transmission lines. (author)

  13. Novel fault tolerant modular system architecture for I and C applications

    International Nuclear Information System (INIS)

    Novel fault tolerant 3U modular system architecture has been developed for safety related and safety critical I and C systems of the reactor. Design innovatively utilizes simplest multi-drop serial bus called Inter-Integrated Circuits (I2C) Bus for system operation with simplicity, fault tolerance and online maintainability (hot swap). I2C bus failure modes analysis was done and system design was hardened for possible failure modes. System backplane uses only passive components, dual redundant I2C buses, data consistency checks and geographical addressing scheme to tackle bus lock ups/stuck buses and bit flips in data transactions. Dual CPU active/standby redundancy architecture with hot swap implements tolerance for CPU software stuck up conditions and hardware faults. System cards implement hot swap for online maintainability, power supply fault containment, communication buses fault containment and I/O channel to channel isolation and independency. Typical applications for pure hardwired (without real time software) Core Temperature Monitoring System for FBRs, as a Universal Signal Conditioning System for safety related I and C systems and as a complete control system for non nuclear safety systems have also been discussed. (author)

  14. Fractional-order adaptive fault estimation for a class of nonlinear fractional-order systems

    KAUST Repository

    N'Doye, Ibrahima

    2015-07-01

    This paper studies the problem of fractional-order adaptive fault estimation for a class of fractional-order Lipschitz nonlinear systems using fractional-order adaptive fault observer. Sufficient conditions for the asymptotical convergence of the fractional-order state estimation error, the conventional integer-order and the fractional-order faults estimation error are derived in terms of linear matrix inequalities (LMIs) formulation by introducing a continuous frequency distributed equivalent model and using an indirect Lyapunov approach where the fractional-order α belongs to 0 < α < 1. A numerical example is given to demonstrate the validity of the proposed approach.

  15. Active Fault Diagnosis for Hybrid Systems Based on Sensitivity Analysis and EKF

    DEFF Research Database (Denmark)

    Gholami, Mehdi; Schiøler, Henrik; Bak, Thomas

    2011-01-01

    An active fault diagnosis approach for different kinds of faults is proposed. The input of the approach is designed off-line based on sensitivity analysis such that the maximum sensitivity for each individual system parameter is obtained. Using maximum sensitivity, results in a better precision in...... the estimation of the corresponding parameter. The fault detection and isolation is done by comparing the nominal parameters with those estimated by Extended Kalman Filter (EKF). In study, Gaussian noise is used as the input disturbance as well as the measurement noise for simulation. The method is...

  16. Active Fault Detection and Isolation for Hybrid Systems

    DEFF Research Database (Denmark)

    Gholami, Mehdi; Schiøler, Henrik; Bak, Thomas;

    2009-01-01

    An algorithm for active fault detection and isolation is proposed. In order to observe the failure hidden due to the normal operation of the controllers or the systems, an optimization problem based on minimization of test signal is used. The optimization based method imposes the normal and faulty...... models predicted outputs such that their discrepancies are observable by passive fault diagnosis technique. Isolation of different faults is done by implementation a bank of Extended Kalman Filter (EKF) where the convergence criterion for EKF is confirmed by Genetic Algorithm (GA). The method is applied...

  17. Analysis of tremor at the San Andreas Fault at Parkfield

    OpenAIRE

    Horstmann, Tobias

    2013-01-01

    Emergent phase arrivals, low amplitude waveforms, and variable event durations make detection and location of tectonic tremor a non-trivial task. In this work I employ a new method to identify tremor in large datasets using a semi-automated technique, which is comprised of an envelope cross-correlation and a Self-Organizing Map (SOM) algorithm to identify and classify event types. Furthermore, I present a new tremor localization method based on time-reversal imaging techniques.

  18. Fault-tolerant interconnection network and image-processing applications for the PASM parallel processing system

    International Nuclear Information System (INIS)

    The demand for very high speed data processing coupled with falling hardware costs has made large-scale parallel and distributed computer systems both desirable and feasible. Two modes of parallel processing are single instruction stream-multiple data stream (SIMD) and multiple instruction stream-multiple data stream (MIMD). PASM, a partitionable SIMD/MIMD system, is a reconfigurable multimicroprocessor system being designed for image processing and pattern recognition. An important component of these systems is the interconnection network, the mechanism for communication among the computation nodes and memories. Assuring high reliability for such complex systems is a significant task. Thus, a crucial practical aspect of an interconnection network is fault tolerance. In answer to this need, the Extra Stage Cube (ESC), a fault-tolerant, multistage cube-type interconnection network, is define. The fault tolerance of the ESC is explored for both single and multiple faults, routing tags are defined, and consideration is given to permuting data and partitioning the ESC in the presence of faults. The ESC is compared with other fault-tolerant multistage networks. Finally, reliability of the ESC and an enhanced version of it are investigated

  19. Assessment on the influence of resistive superconducting fault current limiter in VSC-HVDC system

    International Nuclear Information System (INIS)

    Highlights: • The role of SFCLs in VSC-HVDC systems was evaluated. • Simulation model based on Korea Jeju-Haenam HVDC power system was designed. • An effect and the feasible locations of resistive SFCLs were evaluated. • DC line-to-line, DC line-to-ground and 3 phase AC faults were imposed and analyzed. - Abstract: Due to fewer risk of commutation failures, harmonic occurrences and reactive power consumptions, Voltage Source Converter (VSC) based HVDC system is known as the optimum solution of HVDC power system for the future power grid. However, the absence of suitable fault protection devices for HVDC system hinders the efficient VSC-HVDC power grid design. In order to enhance the reliability of the VSC-HVDC power grid against the fault current problems, the application of resistive Superconducting Fault Current Limiters (SFCLs) could be considered. Also, SFCLs could be applied to the VSC-HVDC system with integrated AC Power Systems in order to enhance the transient response and the robustness of the system. In this paper, in order to evaluate the role of SFCLs in VSC-HVDC systems and to determine the suitable position of SFCLs in VSC-HVDC power systems integrated with AC power System, a simulation model based on Korea Jeju-Haenam HVDC power system was designed in Matlab Simulink/SimPowerSystems. This designed model was composed of VSC-HVDC system connected with an AC microgrid. Utilizing the designed VSC-HVDC systems, the feasible locations of resistive SFCLs were evaluated when DC line-to-line, DC line-to-ground and three phase AC faults were occurred. Consequently, it was found that the simulation model was effective to evaluate the positive effects of resistive SFCLs for the effective suppression of fault currents in VSC-HVDC systems as well as in integrated AC Systems. Finally, the optimum locations of SFCLs in VSC-HVDC transmission systems were suggested based on the simulation results

  20. Techniques for Fault Detection and Visualization of Telemetry Dependence Relationships for Root Cause Fault Analysis in Complex Systems

    Science.gov (United States)

    Guy, Nathaniel

    This thesis explores new ways of looking at telemetry data, from a time-correlative perspective, in order to see patterns within the data that may suggest root causes of system faults. It was thought initially that visualizing an animated Pearson Correlation Coefficient (PCC) matrix for telemetry channels would be sufficient to give new understanding; however, testing showed that the high dimensionality and inability to easily look at change over time in this approach impeded understanding. Different correlative techniques, combined with the time curve visualization proposed by Bach et al (2015), were adapted to visualize both raw telemetry and telemetry data correlations. Review revealed that these new techniques give insights into the data, and an intuitive grasp of data families, which show the effectiveness of this approach for enhancing system understanding and assisting with root cause analysis for complex aerospace systems.

  1. Fault detection and diagnosis in nonlinear systems a differential and algebraic viewpoint

    CERN Document Server

    Martinez-Guerra, Rafael

    2014-01-01

    The high reliability required in industrial processes has created the necessity of detecting abnormal conditions, called faults, while processes are operating. The term fault generically refers to any type of process degradation, or degradation in equipment performance because of changes in the process's physical characteristics, process inputs or environmental conditions. This book is about the fundamentals of fault detection and diagnosis in a variety of nonlinear systems which are represented by ordinary differential equations. The fault detection problem is approached from a differential algebraic viewpoint, using residual generators based upon high-gain nonlinear auxiliary systems (‘observers’). A prominent role is played by the type of mathematical tools that will be used, requiring knowledge of differential algebra and differential equations. Specific theorems tailored to the needs of the problem-solving procedures are developed and proved. Applications to real-world problems, both with constant an...

  2. Software fault detection and recovery in critical real-time systems: An approach based on loose coupling

    International Nuclear Information System (INIS)

    Highlights: •We analyze fault tolerance in mission-critical real-time systems. •Decoupled architectural model can be used to implement fault tolerance. •Prototype implementation for remote handling control system and service manager. •Recovery from transient faults by restarting services. -- Abstract: Remote handling (RH) systems are used to inspect, make changes to, and maintain components in the ITER machine and as such are an example of mission-critical system. Failure in a critical system may cause damage, significant financial losses and loss of experiment runtime, making dependability one of their most important properties. However, even if the software for RH control systems has been developed using best practices, the system might still fail due to undetected faults (bugs), hardware failures, etc. Critical systems therefore need capability to tolerate faults and resume operation after their occurrence. However, design of effective fault detection and recovery mechanisms poses a challenge due to timeliness requirements, growth in scale, and complex interactions. In this paper we evaluate effectiveness of service-oriented architectural approach to fault tolerance in mission-critical real-time systems. We use a prototype implementation for service management with an experimental RH control system and industrial manipulator. The fault tolerance is based on using the high level of decoupling between services to recover from transient faults by service restarts. In case the recovery process is not successful, the system can still be used if the fault was not in a critical software module

  3. Reflection seismic imaging of the end-glacial Pärvie Fault system, northern Sweden

    Science.gov (United States)

    Juhlin, C.; Dehghannejad, M.; Lund, B.; Malehmir, A.; Pratt, G.

    2010-04-01

    Reflection seismic data were acquired along a c. 23 km long profile over the Pärvie Fault system with a nominal receiver and source spacing of 20 m. An hydraulic breaking hammer was used as a source, generating signals with a penetration depth of about 5-6 km. Steeply dipping reflections from the end-glacial faults are observed, as well as sub-horizontal reflections. The location and orientation of the reflections from the faults agree well with surface geological observations of fault geometries. Reflections from a potential fourth end-glacial fault is observed further to the east along the profile. The more sub-horizontal reflections may originate from gabbroic bodies within the granitic basement or from deeper lying greenstones. Our results indicate that the end-glacial faults dip at moderate to steep dips down to at least 2-3 km depth, and possibly continue at this dip to depths of 6 km. This result has significant implications for determining the state of stress required to activate the faults in the past and in the future.

  4. A Novel Mittag-Leffler Kernel Based Hybrid Fault Diagnosis Method for Wheeled Robot Driving System

    Science.gov (United States)

    Yuan, Xianfeng; Song, Mumin; Zhou, Fengyu; Chen, Zhumin; Li, Yan

    2015-01-01

    The wheeled robots have been successfully applied in many aspects, such as industrial handling vehicles, and wheeled service robots. To improve the safety and reliability of wheeled robots, this paper presents a novel hybrid fault diagnosis framework based on Mittag-Leffler kernel (ML-kernel) support vector machine (SVM) and Dempster-Shafer (D-S) fusion. Using sensor data sampled under different running conditions, the proposed approach initially establishes multiple principal component analysis (PCA) models for fault feature extraction. The fault feature vectors are then applied to train the probabilistic SVM (PSVM) classifiers that arrive at a preliminary fault diagnosis. To improve the accuracy of preliminary results, a novel ML-kernel based PSVM classifier is proposed in this paper, and the positive definiteness of the ML-kernel is proved as well. The basic probability assignments (BPAs) are defined based on the preliminary fault diagnosis results and their confidence values. Eventually, the final fault diagnosis result is archived by the fusion of the BPAs. Experimental results show that the proposed framework not only is capable of detecting and identifying the faults in the robot driving system, but also has better performance in stability and diagnosis accuracy compared with the traditional methods. PMID:26229526

  5. Tectonic reversal of the western Doruneh Fault System: Implications for Central Asian tectonics

    Science.gov (United States)

    Javadi, Hamid Reza; Esterabi Ashtiani, Marzieh; Guest, Bernard; Yassaghi, Ali; Ghassemi, Mohammad Reza; Shahpasandzadeh, Majid; Naeimi, Amir

    2015-10-01

    The left-lateral Doruneh Fault System (DFS) bounds the north margin of the Central Iranian microplate and has played an important role in the structural evolution of the Turkish-Iranian plateau. The western termination of the DFS is a sinistral synthetic branch fault array that shows clear kinematic evidence of having undergone recent slip sense inversion from a dextral array to a sinistral array in the latest Neogene or earliest Quaternary. Similarly, kinematic evidence from the Anarak Metamorphic complex suggests that this complex initially developed at a transpressive left-stepping termination of the DFS and that it was inverted in the latest Neogene to a transtensional fault termination. The recognition that the DFS and other faults in NE Iran were inverted from dextral to sinistral strike slip in the latest Neogene and the likely connection between the DFS and the Herat Fault of Afghanistan suggests that prior to the latest Miocene, all of the north Iranian and northern Afghan ranges were part of a distributed dextral fault network that extended from the west Himalayan syntaxes to the western Alborz. Also, the recognition that regional slip sense inversion occurred across northern and northeastern Iran after the latest Miocene invalidates tectonic models that extrapolate Pleistocene to recent fault slip kinematics and rates back beyond this time.

  6. Fault Rid Through Protection of DFIG Based Wind Generation System

    OpenAIRE

    S. Sajedi; F. Khalifeh; T. Karimi; Z. Khalifeh

    2012-01-01

    This study proposes a fault ride-through strategy for a Doubly Fed Induction Generator (DFIG) to enhance network stability during grid disturbances. To enable efficient computation a reduced order DFIG model is developed that restricts the calculation to the fundamental frequency component. However, the model enhancement introduced in the paper allows the consideration of the alternating components of the rotor current as well which is necessary for triggering the crowbar operation. As protec...

  7. Artificial neural network application for space station power system fault diagnosis

    Science.gov (United States)

    Momoh, James A.; Oliver, Walter E.; Dias, Lakshman G.

    1995-01-01

    This study presents a methodology for fault diagnosis using a Two-Stage Artificial Neural Network Clustering Algorithm. Previously, SPICE models of a 5-bus DC power distribution system with assumed constant output power during contingencies from the DDCU were used to evaluate the ANN's fault diagnosis capabilities. This on-going study uses EMTP models of the components (distribution lines, SPDU, TPDU, loads) and power sources (DDCU) of Space Station Alpha's electrical Power Distribution System as a basis for the ANN fault diagnostic tool. The results from the two studies are contrasted. In the event of a major fault, ground controllers need the ability to identify the type of fault, isolate the fault to the orbital replaceable unit level and provide the necessary information for the power management expert system to optimally determine a degraded-mode load schedule. To accomplish these goals, the electrical power distribution system's architecture can be subdivided into three major classes: DC-DC converter to loads, DC Switching Unit (DCSU) to Main bus Switching Unit (MBSU), and Power Sources to DCSU. Each class which has its own electrical characteristics and operations, requires a unique fault analysis philosophy. This study identifies these philosophies as Riddles 1, 2 and 3 respectively. The results of the on-going study addresses Riddle-1. It is concluded in this study that the combination of the EMTP models of the DDCU, distribution cables and electrical loads yields a more accurate model of the behavior and in addition yielded more accurate fault diagnosis using ANN versus the results obtained with the SPICE models.

  8. Model based fault diagnosis for hybrid systems : application on chemical processes

    OpenAIRE

    Olivier Maget, Nelly; Hétreux, Gilles; Le Lann, Jean-Marc

    2009-01-01

    The complexity and the size of the industrial chemical processes induce the monitoring of a growing number of process variables. Their knowledge is generally based on the measurements of system variables and on the physico-chemical models of the process. Nevertheless, this information is imprecise because of process and measurement noise. So the research ways aim at developing new and more powerful techniques for the detection of process fault. In this work, we present a method for the fault ...

  9. Energy-efficient fault tolerance in multiprocessor real-time systems

    Science.gov (United States)

    Guo, Yifeng

    The recent progress in the multiprocessor/multicore systems has important implications for real-time system design and operation. From vehicle navigation to space applications as well as industrial control systems, the trend is to deploy multiple processors in real-time systems: systems with 4 -- 8 processors are common, and it is expected that many-core systems with dozens of processing cores will be available in near future. For such systems, in addition to general temporal requirement common for all real-time systems, two additional operational objectives are seen as critical: energy efficiency and fault tolerance. An intriguing dimension of the problem is that energy efficiency and fault tolerance are typically conflicting objectives, due to the fact that tolerating faults (e.g., permanent/transient) often requires extra resources with high energy consumption potential. In this dissertation, various techniques for energy-efficient fault tolerance in multiprocessor real-time systems have been investigated. First, the Reliability-Aware Power Management (RAPM) framework, which can preserve the system reliability with respect to transient faults when Dynamic Voltage Scaling (DVS) is applied for energy savings, is extended to support parallel real-time applications with precedence constraints. Next, the traditional Standby-Sparing (SS) technique for dual processor systems, which takes both transient and permanent faults into consideration while saving energy, is generalized to support multiprocessor systems with arbitrary number of identical processors. Observing the inefficient usage of slack time in the SS technique, a Preference-Oriented Scheduling Framework is designed to address the problem where tasks are given preferences for being executed as soon as possible (ASAP) or as late as possible (ALAP). A preference-oriented earliest deadline (POED) scheduler is proposed and its application in multiprocessor systems for energy-efficient fault tolerance is

  10. Investigation of the synthetic experiment system of machine equipment fault diagnosis

    Science.gov (United States)

    Liu, Hongyu; Xu, Zening; Yu, Xiaoguang

    2008-12-01

    The invention and manufacturing of the synthetic experiment system of machine equipment fault diagnosis filled in the blank of this kind of experiment equipment in China and obtained national practical new type patent. By the motor speed regulation system, machine equipment fault imitation system, measuring and monitoring system and analysis and diagnosis system of the synthetic experiment system, students can regulate motor speed arbitrarily, imitate multi-kinds of machine equipment parts fault, collect the signals of acceleration, speed, displacement, force and temperature and make multi-kinds of time field, frequency field and figure analysis. The application of the synthetic experiment system in our university's teaching practice has obtained good effect on fostering professional eligibility in measuring, monitoring and fault diagnosis of machine equipment. The synthetic experiment system has the advantages of short training time, quick desirable result and low test cost etc. It suits for spreading in university extraordinarily. If the systematic software was installed in portable computer, user can fulfill measuring, monitoring, signal processing and fault diagnosis on multi-kinds of field machine equipment conveniently. Its market foreground is very good.

  11. Validation Methods Research for Fault-Tolerant Avionics and Control Systems: Working Group Meeting, 2

    Science.gov (United States)

    Gault, J. W. (Editor); Trivedi, K. S. (Editor); Clary, J. B. (Editor)

    1980-01-01

    The validation process comprises the activities required to insure the agreement of system realization with system specification. A preliminary validation methodology for fault tolerant systems documented. A general framework for a validation methodology is presented along with a set of specific tasks intended for the validation of two specimen system, SIFT and FTMP. Two major areas of research are identified. First, are those activities required to support the ongoing development of the validation process itself, and second, are those activities required to support the design, development, and understanding of fault tolerant systems.

  12. Computer Simulation of Complex Power System Faults under various Operating Conditions

    International Nuclear Information System (INIS)

    A power system is normally treated as a balanced symmetrical three-phase network. When a fault occurs, the symmetry is normally upset, resulting in unbalanced currents and voltages appearing in the network. For the correct application of protection equipment, it is essential to know the fault current distribution throughout the system and the voltages in different parts of the system due to the fault. There may be situations where protection engineers have to analyze faults that are more complex than simple shunt faults. One type of complex fault is an open phase condition that can result from a fallen conductor or failure of a breaker pole. In the former case, the condition is often accompanied by a fault detectable with normal relaying. In the latter case, the condition may be undetected by standard line relaying. The effect on a generator is dependent on the location of the open phase and the load level. If an open phase occurs between the generator terminals and the high-voltage side of the GSU in the switchyard, and the generator is at full load, damaging negative sequence current can be generated. However, for the same operating condition, an open conductor at the incoming transmission lines located in the switchyard can result in minimal negative sequence current. In 2012, a nuclear power generating station (NPGS) suffered series or open phase fault due to insulator mechanical failure in the 345 kV switchyard. This resulted in both reactor units tripping offline in two separate incidents. Series fault on one of the phases resulted in voltage imbalance that was not detected by the degraded voltage relays. These under-voltage relays did not initiate a start signal to the emergency diesel generators (EDG) because they sensed adequate voltage on the remaining phases exposing a design vulnerability. This paper is intended to help protection engineers calculate complex circuit faults like open phase condition using computer program. The impact of this type of

  13. A latent fault Markov model for a highly reliable triplex computer system

    Science.gov (United States)

    Swern, Frederic L.; Bavuso, Salvatore J.; Martensen, Anna L.; Miner, Paul S.

    1987-01-01

    A Markov model of a highly reliable triplex system was constructed to evaluate the probability of system failure as a function of the propagation of latent faults. It is found that if the propagation rate of latent faults is extremely high, they do not significantly affect the probability of system failure, while if the propagation rate is extremely low, the survivability of the system is improved. The propagation rate that is most harmful to the survivability of the system is determined as a function of the duration of the flight. A decrease in the probability of system failure due to latency is noted if the probability of any two faults giving the same output is extremely low.

  14. Comparative study of superconducting fault current limiter both for LCC-HVDC and VSC-HVDC systems

    Science.gov (United States)

    Lee, Jong-Geon; Khan, Umer Amir; Lim, Sung-Woo; Shin, Woo-ju; Seo, In-Jin; Lee, Bang-Wook

    2015-11-01

    High Voltage Direct Current (HVDC) system has been evaluated as the optimum solution for the renewable energy transmission and long-distance power grid connections. In spite of the various advantages of HVDC system, it still has been regarded as an unreliable system compared to AC system due to its vulnerable characteristics on the power system fault. Furthermore, unlike AC system, optimum protection and switching device has not been fully developed yet. Therefore, in order to enhance the reliability of the HVDC systems mitigation of power system fault and reliable fault current limiting and switching devices should be developed. In this paper, in order to mitigate HVDC fault, both for Line Commutated Converter HVDC (LCC-HVDC) and Voltage Source Converter HVDC (VSC-HVDC) system, an application of resistive superconducting fault current limiter which has been known as optimum solution to cope with the power system fault was considered. Firstly, simulation models for two types of LCC-HVDC and VSC-HVDC system which has point to point connection model were developed. From the designed model, fault current characteristics of faulty condition were analyzed. Second, application of SFCL on each types of HVDC system and comparative study of modified fault current characteristics were analyzed. Consequently, it was deduced that an application of AC-SFCL on LCC-HVDC system with point to point connection was desirable solution to mitigate the fault current stresses and to prevent commutation failure in HVDC electric power system interconnected with AC grid.

  15. Application of the fault tree method in reliability analysis of the A-1 reactor control and safety system

    International Nuclear Information System (INIS)

    The ''fault tree'' method and its application in the reliability analysis of the control and safety system of the A-1 nuclear power plant is described. The fault tree is a logical model involving all probable fault combinations of components and subsystems associated with the occurence of the final undesired event - the system failure. The method makes possible a quantitative and qualitative analysis of the system reliability and availability using a digital computer. The aim of the fault tree reliability analysis is to determine the distribution of reliability in the system, to find ''weak spots'' of the system considered and to define minimum repair times for the system components. (author)

  16. Fault Diagnosis of Power System Based on Improved Genetic Optimized BP-NN

    Directory of Open Access Journals (Sweden)

    Yuan Pu

    2015-01-01

    Full Text Available BP neural network (Back-Propagation Neural Network, BP-NN is one of the most widely neural network models and is applied to fault diagnosis of power system currently. BP neural network has good self-learning and adaptive ability and generalization ability, but the operation process is easy to fall into local minima. Genetic algorithm has global optimization features, and crossover is the most important operation of the Genetic Algorithm. In this paper, we can modify the crossover of traditional Genetic Algorithm, using improved genetic algorithm optimized BP neural network training initial weights and thresholds, to avoid the problem of BP neural network fall into local minima. The results of analysis by an example, the method can efficiently diagnose network fault location, and improve fault-tolerance and grid fault diagnosis effect.

  17. Development of New Type Gap Arrester for Earth Fault Protection in AC Feeding System

    Science.gov (United States)

    Ajiki, Kohji; Morimoto, Hiroaki; Hisamizu, Yasuzi; Kinoshita, Nobuo; Takai, Wataru; Sato, Ryogo

    A gap arrester is being used for ground fault protection in AC Feeding System. However there are faults in which a conventional gap arrester burns down in a normal state of circuit. We investigated the cause of the fault in which a gap arrester burns. Then, it was found out that the cause of the fault was the discharge of AC current from the surge voltage. Therefore, we developed a new type gap arrester which does not burn down. The new type gap arrester is composed of a discharge tube and a zinc oxide element which are connected in series. Unnecessary AC current discharge is prevented by this structure. The new type gap arrester is actually used at the railroad track.

  18. Metric Learning Method Aided Data-Driven Design of Fault Detection Systems

    Directory of Open Access Journals (Sweden)

    Guoyang Yan

    2014-01-01

    Full Text Available Fault detection is fundamental to many industrial applications. With the development of system complexity, the number of sensors is increasing, which makes traditional fault detection methods lose efficiency. Metric learning is an efficient way to build the relationship between feature vectors with the categories of instances. In this paper, we firstly propose a metric learning-based fault detection framework in fault detection. Meanwhile, a novel feature extraction method based on wavelet transform is used to obtain the feature vector from detection signals. Experiments on Tennessee Eastman (TE chemical process datasets demonstrate that the proposed method has a better performance when comparing with existing methods, for example, principal component analysis (PCA and fisher discriminate analysis (FDA.

  19. Effect of faults on fluid flow and chloride contamination in a carbonate aquifer system

    Science.gov (United States)

    Maslia, M.L.; Prowell, D.C.

    1990-01-01

    A unified, multidiscipline hypothesis is proposed to explain the anomalous pattern by which chloride has been found in water of the Upper Floridan aquifer in Brunswick, Glynn County, Georgia. Analyses of geophysical, hydraulic, water chemistry, and aquifer test data using the equivalent porous medium (EPM) approach are used to support the hypothesis and to improve further the understanding of the fracture-flow system in this area. Using the data presented herein we show that: (1) four major northeast-southwest trending faults, capable of affecting the flow system of the Upper Floridan aquifer, can be inferred from structural analysis of geophysical data and from regional fault patterns; (2) the proposed faults account for the anomalous northeastward elongation of the potentiometric surface of the Upper Floridan aquifer; (3) the faults breach the nearly impermeable units that confine the Upper Floridan aquifer from below, allowing substantial quantities of water to leak vertically upward; as a result, aquifer transmissivity need not be excessively large (as previously reported) to sustain the heavy, long-term pumpage at Brunswick without developing a steep cone of depression in the potentiometric surface; (4) increased fracturing at the intersection of the faults enhances the development of conduits that allow the upward migration of high-chloride water in response to pumping from the Upper Floridan aquifer; and (5) the anomalous movement of the chloride plume is almost entirely controlled by the faults. ?? 1990.

  20. Discussion on rotational tectonic stress field and the genesis of circum-Ordos landmass fault system

    Institute of Scientific and Technical Information of China (English)

    谢新生

    2004-01-01

    When the resultant of applied forces does not pass through the center of an active landmass, the landmass will rotate, giving rise to a rotational tectonic stress field. The motion of a fault along the principal stress plane is determined by the mechanic features of the plane. Tensile fractures occur on the faults in the direction of the principal extensional stress plane, and fault-depression basins will be formed under a long-term action. Thrusting and overthrusting occur on faults in the direction of the principal compressional stress plane, or folds may be formed as a result. Information on geology shows that the North China landmass, which remained stable and intact for a long time, became disjointed in the Eogene period. In the course of disjunction, anticlockwise rotation took place in the Shanxi-Hebei-Shaanxi (Jin-Ji-Shan) landmass, giving rise to the fault-depression system in its periphery. In the Pliocene epoch the landmass lost stability and its eastern boundary moved westward. As a result, the Shanxi graben system appeared and Ordos landmass was formed. Structural and mechanic features of the main faults around Jin-Ji-Shan landmass can be explained with principal stress plane of a rotational tectonic stress field.