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Journal articles on the topic 'Fault simulators'
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1
Kim, Kyuchull, and Kewal K. Saluja. "HYSIM: Hybrid Fault Simulation for Synchronous Sequential Circuits." VLSI Design 4, no. 3 (January 1, 1996): 181–97. http://dx.doi.org/10.1155/1996/72136.
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The paper identifies the inefficiencies of the critical processes in concurrent fault simulation and proposes methods to remove such inefficiencies in a systematic manner. Also, proposed are dynamic memory usage reduction strategies for concurrent fault simulators. Through extensive step-by-step experimentation, we verified the effectiveness of the proposed methods for performance improvement and identified best memory management strategy for dynamic memory usage reduction. A simulator, HySim, based on the proposed methods is implemented and shown to outperform the existing fault simulators and achieve dramatic memory usage reduction. The HySim maintains fault lists which are subsets of that of a conventional concurrent fault simulator, which yields shorter fault list processing time and reduced dynamic memory usage. It also employs Release-and-Reconstruct method for fault list construction, where any fault list identified to be useless is released immediately. The experimental results show that Release-and-Reconstruct method is very effective in dynamic memory usage reduction.
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Shaw, Bruce E. "Beyond Backslip: Improvement of Earthquake Simulators from New Hybrid Loading Conditions." Bulletin of the Seismological Society of America 109, no. 6 (October 15, 2019): 2159–67. http://dx.doi.org/10.1785/0120180128.
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Abstract A standard approach to loading earthquake simulators involving complex fault system geometries is the backslip method, by which fault‐slip rates are specified and stressing rates giving the specified slip rates are calculated and imposed on the system. This often results in singularities in stressing rate at fault boundaries, and unrealistic hypocenters of events associated with these singularities. We present a new generalized hybrid loading method that combines the ability to drive faults at desired slip rates while loading with more regularized stressing rates, allowing faults to slip in a more natural way. The resulting behavior shows improvement in the depth dependence of seismicity, the distribution of sizes of events, and the depth dependence of slip. We discuss as well the physical implications of the new type of loading.
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Lomask, Jesse, Luisalic Hernandez, Veronica Liceras, Amit Kumar, and Anna Khadeeva. "A seismic to simulation unconventional workflow using automated fault-detection attributes." Interpretation 5, no. 3 (August 31, 2017): SJ41—SJ48. http://dx.doi.org/10.1190/int-2016-0148.1.
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Natural fracture networks (NFNs) are used in unconventional reservoir simulators to model pressure and saturation changes in fractured rocks. These fracture networks are often derived from well data or well data combined with a variety of seismic-derived attributes to provide spatial information away from the wells. In cases in which there is a correlation between faults and fractures, the use of a fault indicator can provide additional constraints on the spatial location of the natural fractures. We use a fault attribute based on fault-oriented semblance as a secondary conditioner for the generation of NFNs. In addition, the distribution of automatically extracted faults from the fault-oriented semblance is used to augment the well-derived statistics for natural fracture generation. Without the benefit of this automated fault-extraction solution, to manually extract the fault-statistical information from the seismic data would be prohibitively tedious and time consuming. Finally, we determine, on a 3D field unconventional data set, that the use of fault-oriented semblance results in simulations that are significantly more geologically reasonable.
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Valiev, Shamil K., and Igor A. Dubrov. "Innovative simulators for automation and telemechanics systems." Innotrans, no. 1 (2020): 46–50. http://dx.doi.org/10.20291/2311-164x-2020-1-46-50.
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The article deals with the issues of training in educational institutions and enterprises of railway transport using simulators built on the basis of real actual equipment of railway automation and telemechanics, and virtual simulators that simulate the operation of real equipment by analog or digital modeling. Advantages and disadvantages of real and virtual simulators are considered. The directions for their further improvement are indicated. One of the directions is the development of innovative simulators that combine real equipment and its virtual environment in one laboratory layout. The first innovative simulator at the Department of “Automation, telemechanics and communication on railway transport” is the automated workplace of the train dispatcher. Further improvement of innovative simulators is the development and implementation in the laboratory of station systems of automation and telemechanics of the department of the set of remote fault assignment with an automated workplace of the teacher. The article describes the structural flowcharts of the remote fault assignment set and its main blocks. Innovative simulators also include a simulator of the train passing through the control section KTSM-02, which allows to simulate the operation of floor sensors in the same sequence as when passing a real train. The article describes a virtual simulator, which includes a laboratory model for the study of neutral electromagnetic relays in 3D. Advantages of integrating innovative simulators with virtual educational environment of the University are indicated.
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Luo, Bin, Benchun Duan, and Dunyu Liu. "3D Finite-Element Modeling of Dynamic Rupture and Aseismic Slip over Earthquake Cycles on Geometrically Complex Faults." Bulletin of the Seismological Society of America 110, no. 6 (September 1, 2020): 2619–37. http://dx.doi.org/10.1785/0120200047.
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ABSTRACT We develop a new dynamic earthquake simulator to numerically simulate both spontaneous rupture and aseismic slip over earthquake cycles on geometrically complex fault systems governed by rate- and state-dependent friction. The method is based on the dynamic finite-element method (FEM) EQdyna, which is directly used in the simulator for modeling 3D spontaneous rupture. We apply an adaptive dynamic relaxation technique and a variable time stepping scheme to EQdyna to model the quasi-static processes of an earthquake cycle, including the postseismic, interseismic, and nucleation processes. Therefore, the dynamic and quasi-static processes of an earthquake cycle are modeled in one FEM framework. Tests on a vertical strike-slip fault verify the correctness of the dynamic simulator. We apply the simulator to thrust faults with various dipping angles, which can be considered as the simplest case of geometrically complex faults by breaking symmetry, compared with vertical faults, to examine effects of dipping fault geometry on earthquake cycle behaviors. We find that shallower dipping thrust faults produce larger seismic slip and longer recurrence time over earthquake cycles with the same rupture area. In addition, we find an empirically linear scaling relation between the recurrence interval (and the seismic moment) and the sinusoidal function of the dip angle. The dip-angle dependence is likely due to the free-surface effect, because of broken symmetry. These results suggest dynamic earthquake simulators that can handle nonvertical dipping fault geometry are needed for subduction-zone earthquake studies.
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Węgrzyn, Mariusz, and Janusz Sosnowski. "Tracing Fault Effects in FPGA Systems." International Journal of Electronics and Telecommunications 60, no. 1 (March 1, 2014): 92–97. http://dx.doi.org/10.2478/eletel-2014-0012.
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Abstract The paper presents the extent of fault effects in FPGA based systems and concentrates on transient faults (induced by single event upsets - SEUs) within the configuration memory of FPGA. An original method of detailed analysis of fault effect propagation is presented. It is targeted at microprocessor based FPGA systems using the developed fault injection technique. The fault injection is performed at HDL description level of the microprocessor using special simulators and developed supplementary programs. The proposed methodology is illustrated for soft PicoBlaze microprocessor running 3 programs. The presented results reveal some problems with fault handling at the software level.
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Nilsen, Halvor M., K. A. A. Lie, and Jostein R. Natvig. "Accurate Modeling of Faults by Multipoint, Mimetic, and Mixed Methods." SPE Journal 17, no. 02 (June 7, 2012): 568–79. http://dx.doi.org/10.2118/149690-pa.
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Summary The predominant way of modeling faults in industry-standard flow simulators is to introduce so-called transmissibility multipliers in the underlying two-point discretization. Although this approach provides adequate accuracy in many practical cases, two-point discretizations are only consistent for K-orthogonal grids and may introduce significant discretization errors for grids that severely depart from being K-orthogonal. Such grid-distortion errors can be avoided by lateral or vertical stair-stepping of deviated faults at the expense of errors in the geometrical fault description. In other words, modelers have the choice of either making (geometrical) errors by adapting faults to a grid that is almost K-orthogonal, or introducing discretization errors because of the lack of K-orthogonality if the grid is adapted to deviated faults. We propose a method for accurate description of faults in solvers based on a hybridized mixed or mimetic discretization, which also includes the MPFA-O method. The key idea is to represent faults as internal boundaries and calculate fault transmissibilities directly instead of using multipliers to modify grid-dependent transmissibilities. The resulting method is geology-driven and consistent for cells with planar surfaces and thereby avoids the grid errors inherent in the two-point method. We also propose a method to translate fault transmissibility multipliers into fault transmissibilities. This makes our method readily applicable to reservoir models that contain fault multipliers.
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Barall, Michael, and Terry E. Tullis. "The Performance of Triangular Fault Elements in Earthquake Simulators." Seismological Research Letters 87, no. 1 (December 16, 2015): 164–70. http://dx.doi.org/10.1785/0220150163.
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Kim, Joorak, Gyu-Jung Cho, and Jaewon Kim. "Development of Railway Protective Relay Simulator for Real-Time Applications." Applied Sciences 10, no. 1 (December 25, 2019): 191. http://dx.doi.org/10.3390/app10010191.
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Electric railways use a single-phase system, with the line comprising a trolley wire (TF) that supplies power to the load with a neutral wire and an autotransformer (AF) feeder to absorb the return current of the rail. Testing the performance of the protective relay that detects the fault of the traction power-supply system (TPSS) and operates the circuit breaker is very important. Until now, the performance test of protective relays for the TPSS has been conducted via a simple-steady test or using an expensive real-time simulator. However, under a fast-moving environment in which the load consumes a large amount of power, the protective relay must always detect faults and operate properly. This paper proposes a digital simulator that enables the dynamic testing of protective relays without using any steady test and expensive real-time simulators. This simulator includes both external waveform import and internal waveform generation functions. Users can test the operation of the protective relay by entering the waveform generated externally or internally into the protective relay. Additionally, it has the ability to monitor the operating protection elements and pickup time when the protective relay detects a fault and orders the circuit breaker trip.
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Kourouklas, Christos, Rodolfo Console, Eleftheria Papadimitriou, Maura Murru, and Vassilios Karakostas. "Modelling the large earthquakes recurrence times along the North Aegean Trough Fault Zone (Greece) with a physics-based simulator." Geophysical Journal International 225, no. 3 (March 1, 2021): 2135–56. http://dx.doi.org/10.1093/gji/ggab085.
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SUMMARY The recurrence time of large earthquakes above a predefined magnitude threshold on specific faults or fault segments is one of the key parameters for the development of long-term Earthquake Rupture Forecast models. Observational data of successive large earthquakes per fault segment are often limited and thus inadequate for the construction of robust statistical models. The physics-based earthquake simulators are a powerful tool to overcome recurrence data limitations by generating long earthquake records. A physics-based simulator, embodying well known physical processes, is applied in the North Aegean Trough (NAT) Fault Zone (Greece). The application of the simulation is implemented, after defining a five segment source model, aiming at the investigation of the recurrence behaviour of earthquakes with Mw ≥ 6.5 and Mw ≥ 7.0. The detailed examination of the 544 Mw ≥ 6.5 earthquakes included in the simulated catalogue reveals that both single and multiple segmented ruptures can be realized along the NAT. Results of statistical analysis of the interevent times of Mw ≥ 6.5 and Mw≥ 7.0 earthquakes per participating segment to the related ruptures indicate the better performance of the Brownian Passage Time renewal model in comparison to exponential model. These results provide evidence for quasi-periodic recurrence behaviour, agreeing with the elastic rebound theory, instead of Poissonian behaviour.
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Bradley, A. M. "Software for Efficient Static Dislocation-Traction Calculations in Fault Simulators." Seismological Research Letters 85, no. 6 (October 1, 2014): 1358–65. http://dx.doi.org/10.1785/0220140092.
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Manetti, S., and M. C. Piccirilli. "Symbolic simulators for the fault diagnosis of nonlinear analog circuits." Analog Integrated Circuits and Signal Processing 3, no. 1 (January 1993): 59–72. http://dx.doi.org/10.1007/bf01239193.
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Majhi, Ananta K., James Jacob, and Lalit M. Patnaik. "A Novel Path Delay Fault Simulator Using Binary Logic." VLSI Design 4, no. 3 (January 1, 1996): 167–79. http://dx.doi.org/10.1155/1996/25839.
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A novel path delay fault simulator for combinational logic circuits which is capable of detecting both robust and nonrobust paths is presented. Particular emphasis has been given for the use of binary logic rather than the multiple-valued logic as used in the existing simulators which contributes to the reduction of the overall complexity of the algorithm. A rule based approach has been developed which identifies all robust and nonrobust paths tested by a two-pattern test <V1,V2>, while backtracing from the POs to PIs in a depth-first manner. Rules are also given to find probable glitches and to determine how they propagate through the circuit, which enables the identification of nonrobust paths. Experimental results on several ISCAS'85 benchmark circuits demonstrate the efficiency of the algorithm.
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Marshall, James, Robert Gifford, Gedare Bloom, Gabriel Parmer, and Rahul Simha. "Precise Cache Profiling for Studying Radiation Effects." ACM Transactions on Embedded Computing Systems 20, no. 3 (April 2021): 1–25. http://dx.doi.org/10.1145/3442339.
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Increased access to space has led to an increase in the usage of commodity processors in radiation environments. These processors are vulnerable to transient faults such as single event upsets that may cause bit-flips in processor components. Caches in particular are vulnerable due to their relatively large area, yet are often omitted from fault injection testing because many processors do not provide direct access to cache contents and they are often not fully modeled by simulators. The performance benefits of caches make disabling them undesirable, and the presence of error correcting codes is insufficient to correct for increasingly common multiple bit upsets. This work explores building a program’s cache profile by collecting cache usage information at an instruction granularity via commonly available on-chip debugging interfaces. The profile provides a tighter bound than cache utilization for cache vulnerability estimates (50% for several benchmarks). This can be applied to reduce the number of fault injections required to characterize behavior by at least two-thirds for the benchmarks we examine. The profile enables future work in hardware fault injection for caches that avoids the biases of existing techniques.
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Armengol, Joaquim, Louise Travé-Massuyés, Josep Vehi, and Josep Lluís de la Rosa. "A Survey on Interval Model Simulators and their Properties Related to Fault Detection." IFAC Proceedings Volumes 32, no. 2 (July 1999): 7614–22. http://dx.doi.org/10.1016/s1474-6670(17)57300-0.
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Armengol, J. "A Survey on Interval Model Simulators and their Properties Related to Fault Detection." Annual Reviews in Control 24, no. 1 (2000): 31–39. http://dx.doi.org/10.1016/s1367-5788(00)00002-x.
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Armengol, Joaquim, Luoise Travé-Massuyès, Josep Vehí, and Josep Lluís de la Rosa. "A survey on interval model simulators and their properties related to fault detection." Annual Reviews in Control 24 (January 2000): 31–39. http://dx.doi.org/10.1016/s1367-5788(00)90009-9.
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Peters, Elisabeth, Guido Blöcher, Saeed Salimzadeh, Paul J. P. Egberts, and Mauro Cacace. "Modelling of multi-lateral well geometries for geothermal applications." Advances in Geosciences 45 (August 28, 2018): 209–15. http://dx.doi.org/10.5194/adgeo-45-209-2018.
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Abstract. Well inflow modelling in different numerical simulation approaches are compared for a multi-lateral well. Specifically radial wells will be investigated, which can be created using Radial Jet Drilling (RJD). In this technique, powerful hydraulic jets are used to create small diameter laterals (25–50 mm) of limited length (up to 100 m) from a well. The laterals, also called radials, leave the backbone at a 90∘ angle. In this study we compare three numerical simulators and a semi-analytical tool for calculating inflow of a radial well. The numerical simulators are FE approaches (CSMP and GOLEM) and an FV approach with explicit well model (Eclipse®). A series of increasingly complex well configurations is simulated, including one with inflow from a fault. Although all simulators generally are reasonably close in terms of the total well flow (deviations < 4 % for the homogeneous cases), the distribution of the flow over the different parts of the well can vary significantly. Also, the FE approaches are more sensitive to grid size when the flow is dominated by radial flow to the well since they do not include a dedicated well model. In the FE approaches, lower dimensional elements (1-D for the well and 2-D for the faults) were superimposed into a 3-D space. In case the flow is dominated by fracture flow, the results from the FV approach in Eclipse deviates from the FE methods.
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M. Mousa, Hamdy, and Gamal F. Elhady. "Trust Model Development for Cloud Environment using Fuzzy Mamdani and Simulators." INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 13, no. 11 (November 30, 2014): 5142–54. http://dx.doi.org/10.24297/ijct.v13i11.2784.
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Nowadays, Cloud computing is an expanding area in research and industry, which involves virtualization, distributed computing, internet, software, security, web services and etc. A cloud consists of several elements such as clients, data centers and distributed servers, internet and it includes fault tolerance, high availability, effectiveness, scalability, flexibility, reduced overhead for users, reduced cost of ownership, on demand services and etc. Now the next factor is coming, cost of Virtual machines on Data centers and response time. So this paper develop trust model in cloud computing based on fuzzy logic, to explores the coordination between Data Centers and user bound to optimize the application performance, cost of Virtual machines on Data centers and response time using Cloud Computing Analyst.
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Paul, Pijush K., Mark D. Zoback, and Peter H. Hennings. "Fluid Flow in a Fractured Reservoir Using a Geomechanically Constrained Fault-Zone-Damage Model for Reservoir Simulation." SPE Reservoir Evaluation & Engineering 12, no. 04 (July 6, 2009): 562–75. http://dx.doi.org/10.2118/110542-pa.
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Summary Secondary fractures and faults associated with reservoir-scale faults affect both permeability and permeability anisotropy and hence play an important role in controlling the production behavior of a faulted reservoir. It is well known from geologic studies that there is a concentration of secondary fractures and faults in damage zones adjacent to large faults. Because there are usually inadequate data to fully incorporate damage-zone fractures and faults into reservoir-simulation models, this study uses the principles of dynamic rupture propagation from earthquake seismology to predict the nature of fractured/damage zones associated with reservoir-scale faults. We include geomechanical constraints in our reservoir model and propose a generalized workflow to incorporate damage zones into reservoir-simulation models more routinely. The model we propose calculates the extent of the damage zone along the fault plane by estimating the volume of rock brought to failure by the stress perturbation associated with dynamic-rupture propagation. We apply this method to a real reservoir using both field- and well-scale observations. At the rupture front, damage intensity gradually decreases as we move away from the rupture front or fault plane. In the studied reservoir, the secondary-failure planes in the damage zone are high-angle normal faults striking subparallel to the parent fault, which may affect the permeability of the reservoir in both horizontal and vertical directions. We calibrate our modeling with both outcrop and well observations from a number of studies. We show that dynamic-rupture propagation gives a reasonable first-order approximation of damage zones in terms of permeability and permeability anisotropy in order to be incorporated into reservoir simulators. Introduction Fractures and faults in reservoirs present both problems and opportunities for exploration and production. The heterogeneity and complexity of fluid-flow paths in fractured rocks make it difficult to predict how to produce a fractured reservoir optimally. It is usually not possible to fully define the geometry of the fractures and faults controlling flow, and it is difficult to integrate data from markedly different scales (i.e., seismic, well log, core) into reservoir-simulation models. A number of studies in hydrogeology and the petroleum industry have dealt with modeling fractured reservoirs (Martel and Peterson 1991; Lee et al. 2001; Long and Billaux 1987; Gringarten 1996; Matthäi et al. 2007). Various methodologies, both deterministic and stochastic, have been developed to model the effects of reservoir heterogeneity on hydrocarbon flow and recovery. The work by Smart et al. (2001), Oda (1985, 1986), Maerten et al. (2002), Bourne and Willemse (2001), and Brown and Bruhn (1998) quantifies the stress sensitivity of fractured reservoirs. Several studies (Barton et al. 1995; Townend and Zoback 2000; Wiprut and Zoback 2000) that include fracture characterizations from wellbore images and fluid conductivity from the temperature and the production logs indicate fluid flow from critically stressed fractures. Additional studies emphasize the importance and challenges of coupling geomechanics in reservoir fluid flow (Chen and Teufel 2000; Couples et al. 2003; Bourne et al. 2000). These studies found that a variety of geomechanical factors may be very significant in some of the fractured reservoirs. Secondary fractures and faults associated with large-scale faults also appear to be quite important in controlling the permeability of some reservoirs. Densely concentrated secondary fractures and faults near large faults are often referred to as damage zones, which are created at various stages of fault evolution: before faulting (Aydin and Johnson 1978; Lyakhovsky et al. 1997; Nanjo et al. 2005), during fault growth (Chinnery 1966; Cowie and Scholz 1992; Anders and Wiltschko 1994; Vermily and Scholz 1998; Pollard and Segall 1987; Reches and Lockner 1994), and during the earthquake slip events (Freund 1974; Suppe 1984; Chester and Logan 1986) along the existing faults. Lockner et al. (1992) and Vermilye and Scholz (1998) show that the damage zones from the prefaulting stage are very narrow and can be ignored for reservoir-scale faults. The damage zone formed during fault growth can be modeled using dynamic rupture propagation along a fault plane (Madariaga 1976; Kostov 1964; Virieux and Madariaga 1982; Harris and Day 1997). Damage zones caused by slip on existing faults are important, especially when faults are active in present-day stress conditions because slip creates splay fractures at the tips of the fault and extends the damage zone created during the fault-growth stage (Collettini and Sibson 2001; Faulkner et al. 2006; Lockner and Byerlee 1993; Davatzes and Aydin 2003; Myers and Aydin 2004). In this paper, we first introduce a reservoir in which there appears to be significant permeability anisotropy associated with flow parallel to large reservoir-scale faults. Next, we build a geomechanical model of the field and then discuss the relationship between fluid flow and geomechanics at well-scale fracture and fault systems. To consider what happens in the reservoir at larger scale, we use dynamic rupture modeling to theoretically predict the size and extent of damage zones associated with the reservoir-scale faults.
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Hainzl, Sebastian, Gert Zöller, Gilbert B. Brietzke, and Klaus-G. Hinzen. "Comparison of deterministic and stochastic earthquake simulators for fault interactions in the Lower Rhine Embayment, Germany." Geophysical Journal International 195, no. 1 (August 7, 2013): 684–94. http://dx.doi.org/10.1093/gji/ggt271.
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Liu, Fuqiang, Yan Long, Jun Luo, Huayan Pu, Chaoqun Duan, and Songyi Zhong. "Active Fault Localization of Actuators on Torpedo-Shaped Autonomous Underwater Vehicles." Sensors 21, no. 2 (January 11, 2021): 476. http://dx.doi.org/10.3390/s21020476.
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To ensure the mission implementation of Autonomous Underwater Vehicles (AUVs), faults occurring on actuators should be detected and located promptly; therefore, reliable control strategies and inputs can be effectively provided. In this paper, faults occurring on the propulsion and attitude control systems of a torpedo-shaped AUV are analyzed and located while fault features may induce confusions for conventional fault localization (FL). Selective features of defined fault parameters are assorted as necessary conditions against different faulty actuators and synthesized in a fault tree subsequently to state the sufficiency towards possible abnormal parts. By matching fault features with those of estimated fault parameters, suspected faulty sections are located. Thereafter, active FL strategies that analyze the related fault parameters after executing purposive actuator control are proposed to provide precise fault location. Moreover, the generality of the proposed methods is analyzed to support extensive implementations. Simulations based on finite element analysis against a torpedo-shaped AUV with actuator faults are carried out to illustrate the effectiveness of the proposed methods.
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Liu, Fuqiang, Yan Long, Jun Luo, Huayan Pu, Chaoqun Duan, and Songyi Zhong. "Active Fault Localization of Actuators on Torpedo-Shaped Autonomous Underwater Vehicles." Sensors 21, no. 2 (January 11, 2021): 476. http://dx.doi.org/10.3390/s21020476.
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To ensure the mission implementation of Autonomous Underwater Vehicles (AUVs), faults occurring on actuators should be detected and located promptly; therefore, reliable control strategies and inputs can be effectively provided. In this paper, faults occurring on the propulsion and attitude control systems of a torpedo-shaped AUV are analyzed and located while fault features may induce confusions for conventional fault localization (FL). Selective features of defined fault parameters are assorted as necessary conditions against different faulty actuators and synthesized in a fault tree subsequently to state the sufficiency towards possible abnormal parts. By matching fault features with those of estimated fault parameters, suspected faulty sections are located. Thereafter, active FL strategies that analyze the related fault parameters after executing purposive actuator control are proposed to provide precise fault location. Moreover, the generality of the proposed methods is analyzed to support extensive implementations. Simulations based on finite element analysis against a torpedo-shaped AUV with actuator faults are carried out to illustrate the effectiveness of the proposed methods.
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Tasic, Bratislav, Jos J. Dohmen, E. Jan W. ter Maten, Theo G.J. Beelen, Wil H.A. Schilders, Alex de Vries, and Maikel van Beurden. "Robust DC and efficient time-domain fast fault simulation." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 33, no. 4 (July 1, 2014): 1161–74. http://dx.doi.org/10.1108/compel-12-2012-0364.
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Purpose – Imperfections in manufacturing processes may cause unwanted connections (faults) that are added to the nominal, “golden”, design of an electronic circuit. By fault simulation one simulates all situations. Normally this leads to a large list of simulations in which for each defect a steady-state (direct current (DC)) solution is determined followed by a transient simulation. The purpose of this paper is to improve the robustness and the efficiency of these simulations. Design/methodology/approach – Determining the DC solution can be very hard. For this the authors present an adaptive time-domain source stepping procedure that can deal with controlled sources. The method can easily be combined with existing pseudo-transient procedures. The method is robust and efficient. In the subsequent transient simulation the solution of a fault is compared to a golden, fault-free, solution. A strategy is developed to efficiently simulate the faulty solutions until their moment of detection. Findings – The paper fully exploits the hierarchical structure of the circuit in the simulation process to bypass parts of the circuit that appear to be unaffected by the fault. Accurate prediction and efficient solution procedures lead to fast fault simulation. Originality/value – The fast fault simulation helps to store a database with detectable deviations for each fault. If such a detectable output “matches” a result of a product that has been returned because of malfunctioning it helps to identify the subcircuit that may contain the real fault. One aims to detect as much as possible candidate faults. Because of the many options the simulations must be very efficient.
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Rahaman, Munshi Mostafijur, Prasun Ghosal, and Tuhin Subhra Das. "Latency, Throughput and Power Aware Adaptive NoC Routing on Orthogonal Convex Faulty Region." Journal of Circuits, Systems and Computers 28, no. 04 (March 31, 2019): 1950055. http://dx.doi.org/10.1142/s0218126619500555.
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Reliability of a Network-on-Chip (NoC) relies vastly upon the efficiency of handling faults. Faults those lead to trouble during on-chip communication process are basically of two types namely soft and hard. Here, hard faults are considered. Hard faults may be caused due to failure of links, routers, or other processing units. These are mainly dealt with fault-tolerant routing algorithms or by employing redundant hardware. Multiple faulty nodes are being avoided by acquiring region-based approaches. Most of the fault-tolerant routing techniques are designed on homogeneous faulty regions where some active nodes also act as deactivated nodes to build the region homogeneous. On the other hand, adaptive routing on nonhomogeneous faulty regions increases load on its boundary and most of them does not assure deadlock freeness. This paper proposes a deadlock-free adaptive fault-tolerant NoC routing named F-Route-NoC-Mesh (FRNM) ignoring any virtual channel on orthogonal convex faulty regions. Contributions of this work focus on balancing network traffic by assuming a virtual faulty block boundary and routing packets through this virtual boundary. Destination does not exist within that virtual faulty block regions to reduce load on the boundary of orthogonal faulty regions. Thus, this work is aimed at acquiring proper incorporation of procedures being able to reach fault-tolerant degree, routing efficiency and performance enhancement. Using the proposed algorithm (FRNM), a fault block model-based approach is developed. Significant improvements of average latency (43.37% to 60.44%), average throughput (4.18% to 90.81%) and power consumption (5.93% to 33.28%) are achieved over the state-of-the-art by using a cycle accurate simulator.
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Forouzesh, Alireza, Mohammad S. Golsorkhi, Mehdi Savaghebi, and Mehdi Baharizadeh. "Support Vector Machine Based Fault Location Identification in Microgrids Using Interharmonic Injection." Energies 14, no. 8 (April 20, 2021): 2317. http://dx.doi.org/10.3390/en14082317.
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This paper proposes an algorithm for detection and identification of the location of short circuit faults in islanded AC microgrids (MGs) with meshed topology. Considering the low level of fault current and dependency of the current angle on the control strategies, the legacy overcurrent protection schemes are not effective in in islanded MGs. To overcome this issue, the proposed algorithm detects faults based on the rms voltages of the distributed energy resources (DERs) by means of support vector machine classifiers. Upon detection of a fault, the DER which is electrically closest to the fault injects three interharmonic currents. The faulty zone is identified by comparing the magnitude of the interharmonic currents flowing through each zone. Then, the second DER connected to the faulty zone injects distinctive interharmonic currents and the resulting interharmonic voltages are measured at the terminal of each of these DERs. Using the interharmonic voltages as its features, a multi-class support vector machine identifies the fault location within the faulty zone. Simulations are conducted on a test MG to obtain a dataset comprising scenarios with different fault locations, varying fault impedances, and changing loads. The test results show that the proposed algorithm reliably detects the faults and the precision of fault location identification is above 90%.
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Qi, Xiaomin, Wei Pei, Luyang Li, and Li Kong. "A Fast DC Fault Detection Method for Multi-Terminal AC/DC Hybrid Distribution Network Based on Voltage Change Rate of DC Current-Limiting Inductor." Energies 11, no. 7 (July 12, 2018): 1828. http://dx.doi.org/10.3390/en11071828.
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The rapid detection of direct current (DC) faults is one of the key technologies for the development of multi-terminal alternating current (AC)/DC hybrid distribution networks. The DC fault current rises quickly and affects the whole network. Therefore, DC faults must be detected much faster than AC faults. This paper proposes a fast DC fault detection method based on the voltage change rate of the current-limiting inductor (CLI) for the multi-terminal AC/DC hybrid distribution network. Firstly, the characteristics of the fault voltages and currents and of the CLIs are studied in detail, and the feasibility of using the voltage change rate of the CLI to detect DC fault is analyzed. Based on this, a primary fault detection method is proposed to identify the faulty line, determine the fault type and the fault poles using the amplitudes of the single-ended CLI voltage change rates. For high-resistance DC faults, a backup detection method using the directions and amplitudes of the voltage change rates of the double-ended CLIs is proposed. Finally, the proposed method is verified by MATLAB simulations. The simulation results show that the proposed method can detect all DC faults accurately, and the faulty line, fault type and fault poles can be determined quickly. The proposed method is not affected by the fault location, current-limiting inductance, power reversal of the converters, AC fault and communication delay.
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Yao, L., and A. P. Wang. "Design of a fault-tolerant control scheme for two collaborative subsystems." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 221, no. 6 (September 1, 2007): 875–84. http://dx.doi.org/10.1243/09596518jsce360.
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A fault-tolerant control method is proposed for a class of dynamic systems including two subsystems. These two subsystems work together in order to perform a joint task. The proposed fault-tolerant control aims at obtaining a control strategy that can use the healthy subsystem to compensate the faulty one. When one subsystem is subjected to faults, the other subsystem is used to accommodate faults and compensate the influences onto the total system, leading to a fault-tolerant control of the whole system. Theoretical analysis and computer simulations illustrate the validity of this method.
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Field, Edward H. "Computing Elastic‐Rebound‐Motivated Earthquake Probabilities in Unsegmented Fault Models: A New Methodology Supported by Physics‐Based Simulators." Bulletin of the Seismological Society of America 105, no. 2A (January 27, 2015): 544–59. http://dx.doi.org/10.1785/0120140094.
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Liu, Xiaoyang, Haizhou Huang, and Jiawei Xiang. "A Personalized Diagnosis Method to Detect Faults in a Bearing Based on Acceleration Sensors and an FEM Simulation Driving Support Vector Machine." Sensors 20, no. 2 (January 11, 2020): 420. http://dx.doi.org/10.3390/s20020420.
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Classification of faults in mechanical components using machine learning is a hot topic in the field of science and engineering. Generally, every real-world running mechanical system exhibits personalized vibration behaviors that can be measured with acceleration sensors. However, faulty samples of such systems are difficult to obtain. Therefore, machine learning methods, such as support vector machine (SVM), neural network (NNs), etc., fail to obtain agreeable fault detection results through smart sensors. A personalized diagnosis fault method is proposed to activate the smart sensor networks using finite element method (FEM) simulations. The method includes three steps. Firstly, the cosine similarity updated FEM models with faults are constructed to obtain simulation signals (fault samples). Secondly, every simulation signal is separated into sub-signals to solve the time-domain indexes to generate the faulty training samples. Finally, the measured signals of unknown samples (testing samples) are inserted into the trained SVM to classify faults. The personalized diagnosis method is applied to detect bearing faults of a public bearing dataset. The classification accuracy ratios of six types of faults are 90% and 92.5%, 87.5% and 87.5%, 85%, and 82.5%, respectively. It confirms that the present personalized diagnosis method is effectiveness to detect faults in the absence of fault samples.
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Farsoni, Saverio, Silvio Simani, and Paolo Castaldi. "Fuzzy and Neural Network Approaches to Wind Turbine Fault Diagnosis." Applied Sciences 11, no. 11 (May 29, 2021): 5035. http://dx.doi.org/10.3390/app11115035.
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The fault diagnosis of safety critical systems such as wind turbine installations includes extremely challenging aspects that motivate the research issues considered in this paper. Therefore, this work investigates two fault diagnosis solutions that exploit the direct estimation of the faults by means of data-driven approaches. In this way, the diagnostic residuals are represented by the reconstructed faults affecting the monitored process. The proposed methodologies are based on fuzzy systems and neural networks used to estimate the nonlinear dynamic relations between the input and output measurements of the considered process and the faults. To this end, the considered prototypes are integrated with auto-regressive with exogenous input descriptions, thus making them able to approximate unknown nonlinear dynamic functions with arbitrary degree of accuracy. These residual generators are estimated from the input and output measurements acquired from a high-fidelity benchmark that simulates the healthy and the faulty behaviour of a wind turbine system. The robustness and the reliability features of the developed solutions are validated in the presence of model-reality mismatch and modelling error effects featured by the wind turbine simulator. Moreover, a hardware-in-the-loop tool is implemented for testing and comparing the performance of the developed fault diagnosis strategies in a more realistic environment and with respect to different fault diagnosis approaches. The achieved results have demonstrated the effectiveness of the developed schemes also with respect to more complex model-based and data-driven fault diagnosis methodologies.
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Samier, Pierre, Atef Onaisi, and Sergio de Gennaro. "A Practical Iterative Scheme for Coupling Geomechanics With Reservoir Simulation." SPE Reservoir Evaluation & Engineering 11, no. 05 (October 1, 2008): 892–901. http://dx.doi.org/10.2118/107077-pa.
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Summary The use of reservoir simulation coupled with geomechanics has been increasing in recent years as its utility in modeling physical phenomena such as compaction, subsidence, induced fracturing, enhancement of natural fractures and/or fault activation, and steam-assisted gravity drainage (SAGD) recovery has become apparent. Among different methods investigated by researchers, the iterative explicit method appears to be the preferred method for field-scale simulation. This method is a loose coupled approach between a reservoir simulator and a geomechanical simulator. At user-defined steps, the fluid pressures are transmitted to the geomechanical tool, which computes the actual stresses and reports the modifications of porosities and permeabilities back to the reservoir simulator. This paper presents a new iterative scheme that allows any reservoir simulator to be coupled with any nonlinear finite-element-method (FEM) package for the stress analysis without any limitation on the functionality of either simulator. The convergence of this new scheme is discussed, and results are presented for three cases described below. The first case is a validation case used by other SPE papers. The second case is a synthetic model of a highly compacting reservoir sensitive to water saturation. The third case is a full-field reservoir model. Introduction The importance of geomechanics in problems such as wellbore stability, hydraulic fracturing, and subsidence is well known. In recent years, there has been growing awareness of the importance of the link between fluid flow and geomechanics in the management of stress-sensitive reservoirs (Chen and Teufel 2001; Gutierrez et al. 1994, 1995; Gutierrez and Lewis 1998; Osorio et al. 1999; Settari and Mourits 1998; Somerville and Smart 2000; Stone et al. 2000; Tran et al. 2002). New needs for coupled simulations appear, such as assessing the integrity of the overburden for heavy-oil recovery using thermal mechanisms (e.g., SAGD technique) or for acid-gas injection. Standard reservoir simulation of compaction drive accounts for nonlinear porosity changes determined from uniaxial-strain tests on cores. In many cases, laboratory-derived compressibility must be adjusted to match the contribution of compaction to total hydrocarbon recovery. Geomechanical effects such as stress arching and nonunique stress path are among the causes of discrepancy between laboratory-derived and field compressibility factors. If compressibility varies linearly with the mean reservoir pressure, then predictive reservoir modeling can be achieved without coupling between stress and flow. However, geomechanical effects are rarely linear, for a number of reasons. These include load variations because of modification of pressure, temperature, and saturation; change of the mechanism of production; and progressive activation of faults, and fractures that affect mechanisms such as stress arching and a nonlinear stress path. Unlike standard compaction-drive simulation, there is no simple linear method to account for the effects of stress on permeability, especially for fractured systems, in which the changes of permeability might be directional, localized, and strongly nonlinear. There are several ways to achieve the coupling between flow and stress (Charlier et al. 2002; Samier et al. 2006; Yale 2002; Chen and Teufel 2000; Koutsabeloulis and Hope 1998; Lewis and Ghafouri 1997; Settari and Walters 1999; Mainguy and Longuemare 2002; Dean et al. 2006; Gutierrez and Lewis 1998; Thomas et al. 2002). The most rigorous coupling is achieved with fully coupled simulators, which not only solve the flow and the mechanical equations simultaneously but also allow for anisotropy and nonlinearity of the rock constitutive model. The feasibility and accuracy of such simulators, as far as complex and large-scale reservoir systems are concerned, have yet to be proved. Partial coupling on the other hand consists of linking a flow simulator with a stress simulator, allowing a good compromise between feasibility and accuracy. A one-way link from flow to stress simulator is often used for subsidence forecasts. However, to solve the compaction-drive problem, one-way coupling is not sufficient. To ensure the compatibility of pore-volume calculations from the flow and the stress simulators, iterations must be performed within each stress-analysis step before proceeding to the next stress step with or without permeability changes.
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Zhang, Chuang, Xiubin Zhao, Chunlei Pang, Yong Wang, Liang Zhang, and Bo Feng. "Improved Fault Detection Method Based on Robust Estimation and Sliding Window Test for INS/GNSS Integration." Journal of Navigation 73, no. 4 (February 28, 2020): 776–96. http://dx.doi.org/10.1017/s0373463319000778.
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Real-time and accurate fault detection and isolation is very important to ensure the reliability and precision of integrated inertial navigation and global navigation satellite systems. In this paper, the detection performance of a residual chi-square method is analysed, and on this basis an improved method of fault detection is proposed. The local test based on a standardised residual is introduced to detect and identify faulty measurements directly. Differing from the traditional method, two appropriate thresholds are selected to calculate the weight factor of each measurement, and the gain matrix is adjusted adaptively to reduce the influence of the undetected faulty measurement. The sliding window test, which uses past measurements, is also added to further improve the fault detection performance for small faults when the local test based on current measurements cannot judge whether a fault has occurred or not. Several simulations are conducted to evaluate the proposed method. The results show that the improved method has better fault detection performance than the traditional detection method, especially for small faults, and can improve the reliability and precision of the navigation system effectively.
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Li, Yi, Ping Xu, and Han Wan. "A Fault Injection System Based on QEMU Simulator and Designed for BIT Software Testing." Applied Mechanics and Materials 347-350 (August 2013): 580–87. http://dx.doi.org/10.4028/www.scientific.net/amm.347-350.580.
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An important step in the development of dependable systems is the validation of their fault tolerance properties. Fault injection has been widely used for this purpose. This paper presents a simulator implemented fault injection and monitoring environment based on the QEMU platform, called BitVaSim, which is targeted for the embedded development boards equipped with PowerPC or ARM processor together with Built-In Test software operating environment.BitVaSim takes advantage of simulation and do no harm or irruption to either the real hardware or the software, in addition, all the simulated parts are reachable so that more fault modes are available to achieve.BitVaSim uses abstract key-value pairs to describe the functional fault modes, and then simulates the hardware board as while as realistic faults incurred by hardware into the simulator, in order to monitor the activation of the faults and their impact on the target system especially the BIT system behavior in detail. Fault injection interfaces are configured to implement failure mode matching and fault conditions triggering to inject faults on demand in simulator runtime.Faults injected by BitVaSim can affect any process running on the target system (including the kernel), and it is possible to inject faults in applications for which the source code is not available.Experimental results are presented to demonstrate the accuracy and potential of BitVaSim in the evaluation of the dependability properties of the complex computer systems and the BIT system.
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Frehn, Anica, Soroush Azarian, Gesa Quistorf, Stephan Adloff, Fritz Santjer, and Antonello Monti. "First comparison of the electrical properties of two grid emulators for UVRT test against field measurement." Forschung im Ingenieurwesen 85, no. 2 (April 1, 2021): 373–84. http://dx.doi.org/10.1007/s10010-021-00476-9.
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AbstractThe technical rules for connecting turbines to the medium, high or extra-high voltage grid in Germany require the certification of the UVRT characteristics of wind turbines. The state-of-art voltage divider-based test equipment, also named UVRT-Container, is well equipped for executing UVRT tests in field. To conduct the UVRT in field the full wind turbine should be already installed. A second option to perform UVRT tests are system level test benches. They enable the testing of the nacelle. The components that are not actually present, such as the turbine tower or the blades, are emulated via a mechanical hardware in the loop (HiL) system. In this work, for the first time, the performance of two different grid simulators installed at the DyNaLab at Fraunhofer IWES and at the CWD at RWTH Aachen University is compared with a field measurement of the same type of wind turbine. Thus, not only a system test bench measurement is compared to a field measurement. Rather, two system test benches with individual technical approaches are additionally compared with each other. The focus of this work is to investigate the characteristics of the grid simulators within the steady-state range of the UVRT tests to replicate identical fault shapes on the test benches and in the field.
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Wang, Shizhuang, Xingqun Zhan, Yawei Zhai, and Baoyu Liu. "Fault Detection and Exclusion for Tightly Coupled GNSS/INS System Considering Fault in State Prediction." Sensors 20, no. 3 (January 21, 2020): 590. http://dx.doi.org/10.3390/s20030590.
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To ensure navigation integrity for safety-critical applications, this paper proposes an efficient Fault Detection and Exclusion (FDE) scheme for tightly coupled navigation system of Global Navigation Satellite Systems (GNSS) and Inertial Navigation System (INS). Special emphasis is placed on the potential faults in the Kalman Filter state prediction step (defined as “filter fault”), which could be caused by the undetected faults occurring previously or the Inertial Measurement Unit (IMU) failures. The integration model is derived first to capture the features and impacts of GNSS faults and filter fault. To accommodate various fault conditions, two independent detectors, which are respectively designated for GNSS fault and filter fault, are rigorously established based on hypothesis-test methods. Following a detection event, the newly-designed exclusion function enables (a) identifying and removing the faulty measurements and (b) eliminating the effect of filter fault through filter recovery. Moreover, we also attempt to avoid wrong exclusion events by analyzing the underlying causes and optimizing the decision strategy for GNSS fault exclusion accordingly. The FDE scheme is validated through multiple simulations, where high efficiency and effectiveness have been achieved in various fault scenarios.
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Tian, Zhiyu, Ting-Ting Y. Lin, Shiyuan Yang, and Shibai Tong. "The Faulty Behavior of Feedforward Neural Networks with Hard-Limiting Activation Function." Neural Computation 9, no. 5 (July 1, 1997): 1109–26. http://dx.doi.org/10.1162/neco.1997.9.5.1109.
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With the progress in hardware implementation of artificial neural networks, the ability to analyze their faulty behavior has become increasingly important to their diagnosis, repair, reconfiguration, and reliable application. The behavior of feedforward neural networks with hard limiting activation function under stuck-at faults is studied in this article. It is shown that the stuck-at-M faults have a larger effect on the network's performance than the mixed stuck-at faults, which in turn have a larger effect than that of stuck-at-0 faults. Furthermore, the fault-tolerant ability of the network decreases with the increase of its size for the same percentage of faulty interconnections. The results of our analysis are validated by Monte-Carlo simulations.
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FERNÁNDEZ-ZEPEDA, JOSÉ ALBERTO, ALEJANDRO ESTRELLA-BALDERRAMA, and ANU G. BOURGEOIS. "DESIGNING FAULT TOLERANT ALGORITHMS FOR RECONFIGURABLE MESHES." International Journal of Foundations of Computer Science 16, no. 01 (February 2005): 71–88. http://dx.doi.org/10.1142/s0129054105002875.
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This paper proposes a procedure to design fault tolerant algorithms for the R-Mesh and some of its restrictive variations. This procedure first identifies a healthy sub-mesh from a faulty model using the bypass and removal fault model. Then it uses scalable algorithms to simulate the larger faulty model on the resulting healthy sub-mesh. The algorithms for the bypass model tolerates n faults in an n×n R-Mesh (LR-Mesh) and runs in O(T log n) (O(T)) time, where T is the execution time on the original mesh without faults. For the removal model, we design fault tolerant algorithms for some interesting variations of the R-Mesh, specifically, the NXR-Mesh and the NXLR-Mesh. We propose the first scaling simulations for these models and present a simulation of the R-Mesh on the NXR-Mesh. The results of this paper enable us to consider certain reconfigurable models in a more practical environment than previously allowed.
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Laurent, J., C. Deleuze, F. Pebay-Peyroula, and V. Beroulle. "Bridging the Gap between RTL and Software Fault Injection." ACM Journal on Emerging Technologies in Computing Systems 17, no. 3 (May 11, 2021): 1–24. http://dx.doi.org/10.1145/3446214.
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Protecting programs against hardware fault injection requires accurate software fault models. However, typical models, such as the instruction skip, do not take into account the microarchitecture specificities of a processor. We propose in this article an approach to study the relation between faults at the Register Transfer Level (RTL) and faults at the software level. The goal is twofold: accurately model RTL faults at the software level and materialize software fault models to actual RTL injections. These goals lead to a better understanding of a system's security against hardware fault injection, which is important to design effective and cost-efficient countermeasures. Our approach is based on the comparison between results from RTL simulations and software injections (using a program mutation tool). Various analyses are included in this article to give insight on the relevance of software fault models, such as the computation of a coverage and fidelity metric, and to link software fault models to hardware RTL descriptions. These analyses are applied on various single-bit and multiple-bit injection campaigns to study the faulty behaviors of a RISC-V processor.
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Deng, Yong, Yibing Shi, and Wei Zhang. "Diagnosis of Incipient Faults in Nonlinear Analog Circuits." Metrology and Measurement Systems 19, no. 2 (January 1, 2012): 203–18. http://dx.doi.org/10.2478/v10178-012-0018-7.
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Diagnosis of Incipient Faults in Nonlinear Analog Circuits Considering the problem to diagnose incipient faults in nonlinear analog circuits, a novel approach based on fractional correlation is proposed and the application of the subband Volterra series is used in this paper. Firstly, the subband Volterra series is calculated from the input and output sequences of the circuit under test (CUT). Then the fractional correlation functions between the fault-free case and the incipient faulty cases of the CUT are derived. Using the feature vectors extracted from the fractional correlation functions, the hidden Markov model (HMM) is trained. Finally, the well-trained HMM is used to accomplish the incipient fault diagnosis. The simulations illustrate the proposed method and show its effectiveness in the incipient fault recognition capability.
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Wang, Ban, Peng Huang, and Wei Zhang. "A Robust Fault-Tolerant Control for Quadrotor Helicopters against Sensor Faults and External Disturbances." Complexity 2021 (March 19, 2021): 1–13. http://dx.doi.org/10.1155/2021/6672812.
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This paper presents an active fault-tolerant control strategy for quadrotor helicopters to simultaneously accommodate sensor faults and external disturbances. Unlike most of the existing fault diagnosis and fault-tolerant control schemes for quadrotor helicopters, the proposed fault diagnosis scheme is able to estimate sensor faults while eliminating the effect of external disturbances. Moreover, the proposed fault-tolerant control scheme is capable to eliminate the adverse effect of external disturbances as well by designing a disturbance observer to effectively estimate the unknown external disturbances and integrating with the designed integral sliding-mode controller. In this case, the continuous operation of the quadrotor helicopter is ensured while avoiding the unexpected control chattering. In addition, the stability of the closed-loop system is theoretically proved. Finally, the effectiveness and advantages of the proposed scheme are validated and demonstrated through comparative numerical simulations of the quadrotor helicopter under different faulty and uncertain scenarios.
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Huo, Linsheng, Gangbing Song, Satish Nagarajaiah, and Hongnan Li. "Semi-active vibration suppression of a space truss structure using a fault tolerant controller." Journal of Vibration and Control 18, no. 10 (October 7, 2011): 1436–53. http://dx.doi.org/10.1177/1077546311421514.
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In recent years, magneto-rheological (MR) dampers have been used to control the response of structures. This paper presents the design and application of an H∞ fault detection and isolation (FDI) filter and fault tolerant controller (FTC) for truss vibration control systems using MR dampers. A linear matrix inequality formulation is used to design a full order robust H∞ filter to estimate faulty input signals. A fault tolerant H∞ controller is designed for the combined system of plant and filter, minimizing the control objective selected in the presence of disturbances and faults. A truss structure with an MR damper is used to validate the FDI and FTC controller design through numerical simulations. The residuals obtained from the filter through simulation clearly identify the fault signals. The simulation results of the proposed FTC controller confirm its effectiveness for vibration suppression of the faulty truss system.
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Li, Jian Hu, Man Bok Park, and Hun Mo Kim. "The Fault Tolerant Output Selector Based on Fault-Detection Considering Realistic Fault Modes for Pedal Simulator of Brake-by-Wire System." Applied Mechanics and Materials 284-287 (January 2013): 1946–50. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.1946.
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A brake pedal simulator in a Brake-by-Wire system is studied for fault tolerant control of the brake pedal signals. This study is conducted for the pedal simulator installed with a sensor that generates two analogue signals. Several realistic fault modes recognized by automotive experts have been analyzed. To solve the fault modes, we propose a fault tolerant output selector that can handle transient, intermittent, or permanent faults. The fault tolerant output selector, based on a fault detection algorithm, uses the BLS(brake light switch) signal and the Acc(acceleration pedal) signal to find faults and isolate them. To confirm the system performance, the fault modes were simulated. The result showed the reliability and safety of the pedal simulator for dealing with unexpected faults.
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Xue, Xue, Menghan Cheng, Tianyu Hou, Guanhua Wang, Nan Peng, and Rui Liang. "Accurate Location of Faults in Transmission Lines by Compensating for the Electrical Distance." Energies 13, no. 3 (February 10, 2020): 767. http://dx.doi.org/10.3390/en13030767.
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Accurately locating faults is quite important, especially when the geographical environment is complicated. If the exact location of the fault is not given, wrong route would be chosen, which will greatly slow down repair. This paper proposes an improved traveling wave method by compensating the electrical distance of transmission lines. The catenary model is constructed that considers parameters of the tower and the actual temperature. The actual line length is also derived by the catenary model. A 500 kV transmission line model is established by PSCAD/EMTDC. Various fault simulations are conducted and the results demonstrate that the presented method effectively reduces the error ratio of faulty segment positioning and locates faults with high accuracy.
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Kourd, Yahia, Dimitri Lefebvre, and Noureddine Guersi. "Early FDI Based on Residuals Design According to the Analysis of Models of Faults: Application to DAMADICS." Advances in Artificial Neural Systems 2011 (September 25, 2011): 1–10. http://dx.doi.org/10.1155/2011/453169.
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The increased complexity of plants and the development of sophisticated control systems have encouraged the parallel development of efficient rapid fault detection and isolation (FDI) systems. FDI in industrial system has lately become of great significance. This paper proposes a new technique for short time fault detection and diagnosis in nonlinear dynamic systems with multi inputs and multi outputs. The main contribution of this paper is to develop a FDI schema according to reference models of fault-free and faulty behaviors designed with neural networks. Fault detection is obtained according to residuals that result from the comparison of measured signals with the outputs of the fault free reference model. Then, Euclidean distance from the outputs of models of faults to the measurements leads to fault isolation. The advantage of this method is to provide not only early detection but also early diagnosis thanks to the parallel computation of the models of faults and to the proposed decision algorithm. The effectiveness of this approach is illustrated with simulations on DAMADICS benchmark.
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Chen, Ruinan, and Jian Ou. "A hybrid fault-tolerant control strategy for four-wheel independent drive vehicles." Advances in Mechanical Engineering 13, no. 9 (September 2021): 168781402110454. http://dx.doi.org/10.1177/16878140211045486.
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In this paper, a hybrid fault-tolerant control strategy is putted forward to improve the stability of the four-wheel independent drive (4WID) electric vehicle with motor failures. To improve the handling performance of the vehicle with in-wheel motor failures, the faults of in-wheel motors are analyzed and modeled. Then, a model reference adaptive fault observer was designed to observe the faults in real-time. Based on the observation results, there are designed a model predictive control (MPC) based high-performance active fault-tolerant control (AFTC) strategy and a sliding mode control based high-robust passive fault-tolerant control (PFTC) strategy. However, the fault observation results may not always be accurately. For this circumstance, a hybrid fault-tolerant control strategy was designed to make the control method find a balance between optimality and robustness. Finally, a series of simulations are conducted on a hardware-in-loop (HIL) real-time simulator, the simulation results show that the control strategy designed in this paper is effectiveness.
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Gord, Ehsan, Rahman Dashti, Mojtaba Najafi, and Hamid Reza Shaker. "Real Fault Section Estimation in Electrical Distribution Networks Based on the Fault Frequency Component Analysis." Energies 12, no. 6 (March 24, 2019): 1145. http://dx.doi.org/10.3390/en12061145.
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: Fault location in electrical energy distribution networks is an important task, as faults in distribution grids are among the main causes of electricity supply disruption. Fault location in the distribution systems, however, is a challenging task because of the topology of the distribution networks, as well as the main and side branches. Therefore, it is necessary to address these challenges through an intelligent approach to fault location. In this paper, fault location in electric energy distribution networks is addressed considering the changes in fault distance and fault resistance in the presence of different fault types. A new method for fault location is developed for conditions where the minimum information is available and only information at the beginning of the feeder is used. This facilitates wide adoption of the technique as it does not require significant investments in instrumentation and measurement. The proposed intelligent method is based on the impedance and transient state estimation. This technique employs a specific impedance analysis for determining possible fault locations considering the unbalanced performance of distribution systems, distances, and different fault resistances. To determine the real faulty section, real fault frequency component analysis and the simulated faults at possible fault locations are used. At this stage of the process, it is possible to eliminate multiple estimations with the help of comparison and identification of the similarities. Therefore, a real faulty section is determined. It is observed that some conditions of electric energy distribution networks affect the accuracy and performance of the proposed method significantly; thus, a detailed investigation is conducted to neutralize these conditions. Simulation results and calculations based on MATLAB along with a practical test of the proposed method in power network simulator confirm a satisfactory performance.
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Yuan, Jian, Junhe Wan, Wenxia Zhang, Hailin Liu, and Hao Zhang. "An Underwater Thruster Fault Diagnosis Simulator and Thrust Calculation Method Based on Fault Clustering." Journal of Robotics 2021 (January 25, 2021): 1–10. http://dx.doi.org/10.1155/2021/6635494.
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In order to study the fault diagnosis method of small underwater thruster, an experimental device for fault diagnosis of underwater thruster is designed, and a controller hardware and monitoring software of upper computer and lower computer are developed to realize the acquisition and storage of parameters for underwater propeller. The experimental device can simulate four kinds of thruster faults, collect the hydrophone data, classify the fault types by fault clustering analysis, analyze the spectrum of four types of faults, and calculate the thrust under different fault conditions based on the results of spectrum analysis. The experimental results show that the experimental system effectively simulates different faults of the thruster, and the analysis method realizes the classification of different faults. The thrust loss of different faults is also calculated based on the analysis method.
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Vaagensmith, Bjorn, Vivek Kumar Singh, Robert Ivans, Daniel L. Marino, Chathurika S. Wickramasinghe, Jacob Lehmer, Tyler Phillips, Craig Rieger, and Milos Manic. "Review of Design Elements within Power Infrastructure Cyber–Physical Test Beds as Threat Analysis Environments." Energies 14, no. 5 (March 4, 2021): 1409. http://dx.doi.org/10.3390/en14051409.
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Cyber–physical systems (CPSs) are an integral part of modern society; thus, enhancing these systems’ reliability and resilience is paramount. Cyber–physical testbeds (CPTs) are a safe way to test and explore the interplay between the cyber and physical domains and to cost-effectively enhance the reliability and resilience of CPSs. Here a review of CPT elements, broken down into physical components (simulators, emulators, and physical hardware), soft components (communication protocols, network timing protocols), and user interfaces (visualization-dashboard design considerations) is presented. Various methods used to validate CPS performance are reviewed and evaluated for potential applications in CPT performance validation. Last, initial simulated results for a CPT design, based on the IEEE 33 bus system, are presented, along with a brief discussion on how model-based testing and fault–injection-based testing (using scaling and ramp-type attacks) may be used to help validate CPT performance.
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Woillez, Marie-Noëlle, Christine Souque, Jean-Luc Rudkiewicz, Françoise Willien, and Tristan Cornu. "Insights in Fault Flow Behaviour from Onshore Nigeria Petroleum System Modelling." Oil & Gas Sciences and Technology – Revue d’IFP Energies nouvelles 72, no. 5 (September 2017): 31. http://dx.doi.org/10.2516/ogst/2017029.
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Faults are complex geological features acting either as permeability barrier, baffle or drain to fluid flow in sedimentary basins. Their role can be crucial for over-pressure building and hydrocarbon migration, therefore they have to be properly integrated in basin modelling. The ArcTem basin simulator included in the TemisFlow software has been specifically designed to improve the modelling of faulted geological settings and to get a numerical representation of fault zones closer to the geological description. Here we present new developments in the simulator to compute fault properties through time as a function of available geological parameters, for single-phase 2D simulations. We have used this new prototype to model pressure evolution on a siliciclastic 2D section located onshore in the Niger Delta. The section is crossed by several normal growth faults which subdivide the basin into several sedimentary units and appear to be lateral limits of strong over-pressured zones. Faults are also thought to play a crucial role in hydrocarbons migration from the deep source rocks to shallow reservoirs. We automatically compute the Shale Gouge Ratio (SGR) along the fault planes through time, as well as the fault displacement velocity. The fault core permeability is then computed as a function of the SGR, including threshold values to account for shale smear formation. Longitudinal fault fluid flow is enhanced during periods of high fault slip velocity. The method allows us to simulate both along-fault drainages during the basin history as well as overpressure building at present-day. The simulated pressures are at first order within the range of observed pressures we had at our disposal.