Journal articles on the topic 'Fault properties'
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1
Patan, Krzysztof, and Józef Korbicz. "Nonlinear model predictive control of a boiler unit: A fault tolerant control study." International Journal of Applied Mathematics and Computer Science 22, no. 1 (March 1, 2012): 225–37. http://dx.doi.org/10.2478/v10006-012-0017-6.
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Nonlinear model predictive control of a boiler unit: A fault tolerant control studyThis paper deals with a nonlinear model predictive control designed for a boiler unit. The predictive controller is realized by means of a recurrent neural network which acts as a one-step ahead predictor. Then, based on the neural predictor, the control law is derived solving an optimization problem. Fault tolerant properties of the proposed control system are also investigated. A set of eight faulty scenarios is prepared to verify the quality of the fault tolerant control. Based of different faulty situations, a fault compensation problem is also investigated. As the automatic control system can hide faults from being observed, the control system is equipped with a fault detection block. The fault detection module designed using the one-step ahead predictor and constant thresholds informs the user about any abnormal behaviour of the system even in the cases when faults are quickly and reliably compensated by the predictive controller.
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Karaata, Mehmet Hakan, Ali Hamdan, Maha H. Faisal, and Feda A. AlShawan. "Fault Detection for Message Passing Systems." Journal of Circuits, Systems and Computers 27, no. 05 (February 6, 2018): 1850070. http://dx.doi.org/10.1142/s0218126618500706.
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Many crucial dependable and secure services including atomic commitment, consensus and group membership, and middleware services (such as replica, communication and transaction services) use fault detectors. Through the use of fault detectors, the overlying service can be exempted from failure treatment and synchronization requirements. Fault detection is essential for proving that the services carried out are correct. In this paper, we first identify the necessary conditions to detect faults in a message passing system where multiple disjoint paths exist between each pair of endpoints. We then present the first fault detection protocol capable of detecting message meta-data modification in the presence of various message interferences in addition to other faults including omission faults, message replay and spurious messages using disjoint paths, where paths with faults are not known a priori. In addition, it authenticates message origins allowing Sybil attacks to be detected, identifies faulty paths, and classifies faults in the presence of multiple messages sent by various system processes. We establish the completeness and soundness properties of the proposed algorithm, i.e., it detects each considered fault and each detected fault is an actual fault, respectively. We also show that our algorithm does not yield a significant packet size and delay overheads. The algorithm shows the viability of the use of disjoint paths in fault detection.
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Ray, Sohom, and Robert C. Viesca. "Homogenization of fault frictional properties." Geophysical Journal International 219, no. 2 (July 17, 2019): 1203–11. http://dx.doi.org/10.1093/gji/ggz327.
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SUMMARY The frictional properties of large faults are expected to vary in space. However, fault models often assume that properties are homogeneous, or nearly so. We investigate the conditions under which the details of variations may be neglected and properties homogenized. We do so by examining the behaviour of nonlinear solutions for unstably accelerating fault slip under frictional heterogeneity. We consider a rate- and state-dependent fault friction in which the characteristic wavelength for the property variations is a problem parameter. We find that homogenization is permissible only when that wavelength shows scale separation from an elasto-frictional length scale. However, fault models also often include property transitions that occur over distances comparable to the elasto-frictional length. We show that under such comparable variations, the dynamics of earthquake-nucleating instabilities is controlled by the properties’ spatial distribution.
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Amin, Arslan Ahmed, and Khalid Mahmood-ul-Hasan. "Hybrid fault tolerant control for air–fuel ratio control of internal combustion gasoline engine using Kalman filters with advanced redundancy." Measurement and Control 52, no. 5-6 (April 17, 2019): 473–92. http://dx.doi.org/10.1177/0020294019842593.
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In this paper, a hybrid fault tolerant control system is proposed for air–fuel ratio control of internal combustion gasoline engines based on Kalman filters and triple modular redundancy. Hybrid fault tolerant control system possesses properties of both active fault tolerant control system and passive fault tolerant control system. As part of active fault tolerant control system, fault detection and isolation unit is designed using Kalman filters to provide estimated values of the sensors to the engine controller in case of faults in the sensors. As part of passive fault tolerant control system, a dedicated proportional–integral feedback controller is incorporated to maintain air–fuel ratio by adjusting the throttle actuator in the fuel supply line in faulty and noisy conditions for robustness to faults and sensors’ noise. Redundancy is proposed in the sensors and actuators as a simultaneous failure of more than one sensor, and failure of the single actuator will cause the engine shutdown. Advanced redundancy protocol triple modular redundancy is proposed for the sensors and dual redundancy is proposed for actuators. Simulation results in the MATLAB Simulink environment show that the proposed system remains stable during faults in the sensors and actuators. It also maintains air–fuel ratio without any degradation in the faulty conditions and is robust to noise. Finally, the probabilistic reliability analysis of the proposed model is carried out. The study shows that the proposed hybrid fault tolerant control system with redundant components presents a novel and highly reliable solution for the air–fuel ratio control in internal combustion engines to prevent engine shutdown and production loss for greater profits.
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Hudson, John A., and Enru Liu. "Effective elastic properties of heavily faulted structures." GEOPHYSICS 64, no. 2 (March 1999): 479–85. http://dx.doi.org/10.1190/1.1444553.
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Recent results have shown how to construct the smoothed transmission properties of a plane fault from the parameters of its microstructure in two particular cases. In the first, the fault is modelled as a plane distribution of approximately circular cracks while elsewhere the faces of the fault are held together by the ambient pressure and friction. In the second, the model consists of a plane distribution of approximately circular stuck regions within an area where the faces are separated as for a crack. The averaging method for a sequence of such slip planes enables the construction of overall properties of a material weakened by a series of parallel faults. With the first model, where the distribution of cracks is sparse, this approach leads to exactly the same expressions to first order in the number density as for dilute volume distributions of cracks. The higher‐order terms do not agree since they refer to crack‐crack interactions and in the Schoenberg‐Douma averaging process only the overall interactions between faults are allowed for, not individual interactions between cracks on different faults. Application of this procedure to the second model, in which the fracture density is high, gives for the first time an exact first‐order formula for the overall properties of heavily cracked material, the cracks being aligned and confined to the fault planes. These expressions are first order in the (small) parameter, denoting the proportion of each slip plane that is welded. The unwelded part may be free (any cracks) or filled with an incompressible inviscid fluid. An alternative approach in either case is to replace each fault or slip plane by an equivalent thin layer of material whose properties are related, at least in part, to the structure of the fault. The corresponding process of averaging over the layers is, in this case, the original Backus method. Comparison between the properties of the equivalent layers for dilute cracks and for extended cracking leads to an extension of the slip relations on a single heavily cracked fault to cases where the cracks contain secondary material with arbitrary elastic properties. Finally, results for a stack of parallel, heavily cracked faults is identical, to first order in the number density of the contact regions on the faults, to those for a cubical packing of spheres. This further reveals the insensitivity of first‐order results to many of the details of the microstructure.
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Bossard, Antoine, and Keiichi Kaneko. "Cluster-Fault Tolerant Routing in a Torus." Sensors 20, no. 11 (June 9, 2020): 3286. http://dx.doi.org/10.3390/s20113286.
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The number of Internet-connected devices grows very rapidly, with even fears of running out of available IP addresses. It is clear that the number of sensors follows this trend, thus inducing large sensor networks. It is insightful to make the comparison with the huge number of processors of modern supercomputers. In such large networks, the problem of node faults necessarily arises, with faults often happening in clusters. The tolerance to faults, and especially cluster faults, is thus critical. Furthermore, thanks to its advantageous topological properties, the torus interconnection network has been adopted by the major supercomputer manufacturers of the recent years, thus proving its applicability. Acknowledging and embracing these two technological and industrial aspects, we propose in this paper a node-to-node routing algorithm in an n -dimensional k -ary torus that is tolerant to faults. Not only is this algorithm tolerant to faulty nodes, it also tolerates faulty node clusters. The described algorithm selects a fault-free path of length at most n ( 2 k + ⌊ k / 2 ⌋ − 2 ) with an O ( n 2 k 2 | F | ) worst-case time complexity with F the set of faulty nodes induced by the faulty clusters.
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Kang, Xuejiao, David F. Gleich, Ahmed Sameh, and Ananth Grama. "Adaptive Erasure Coded Fault Tolerant Linear System Solver." ACM Transactions on Parallel Computing 8, no. 4 (December 31, 2021): 1–19. http://dx.doi.org/10.1145/3490557.
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As parallel and distributed systems scale, fault tolerance is an increasingly important problem—particularly on systems with limited I/O capacity and bandwidth. Erasure coded computations address this problem by augmenting a given problem instance with redundant data and then solving the augmented problem in a fault oblivious manner in a faulty parallel environment. In the event of faults, a computationally inexpensive procedure is used to compute the true solution from a potentially fault-prone solution. These techniques are significantly more efficient than conventional solutions to the fault tolerance problem. In this article, we show how we can minimize, to optimality, the overhead associated with our problem augmentation techniques for linear system solvers. Specifically, we present a technique that adaptively augments the problem only when faults are detected. At any point in execution, we only solve a system whose size is identical to the original input system. This has several advantages in terms of maintaining the size and conditioning of the system, as well as in only adding the minimal amount of computation needed to tolerate observed faults. We present, in detail, the augmentation process, the parallel formulation, and evaluation of performance of our technique. Specifically, we show that the proposed adaptive fault tolerance mechanism has minimal overhead in terms of FLOP counts with respect to the original solver executing in a non-faulty environment, has good convergence properties, and yields excellent parallel performance. We also demonstrate that our approach significantly outperforms an optimized application-level checkpointing scheme that only checkpoints needed data structures.
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Kuo, Che-Nan. "Every edge lies on cycles embedding in folded hypercubes with both vertex and edge faults." Discrete Mathematics, Algorithms and Applications 08, no. 01 (February 26, 2016): 1650001. http://dx.doi.org/10.1142/s1793830916500014.
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The folded hypercube is a well-known variation of hypercube structure and can be constructed from a hypercube by adding an edge to every pair of vertices with complementary addresses. Let [Formula: see text] (respectively, [Formula: see text]) denote the set of faulty vertices (respectively, faulty edges) in an [Formula: see text]-dimensional folded hypercube [Formula: see text]. In the case that all edges in [Formula: see text] are fault-free, Cheng et al. [Cycles embedding on folded hypercubes with faulty vertices, Discrete Appl. Math. 161 (2013) 2894–2900] has shown that (1) every fault-free edge of [Formula: see text] lies on a fault-free cycle of every even length from [Formula: see text] to [Formula: see text] if [Formula: see text], where [Formula: see text]; and (2) every fault-free edge of [Formula: see text] lies on a fault-free cycle of every odd length from [Formula: see text] to [Formula: see text] if [Formula: see text], where [Formula: see text] is even. In this paper, we extend Cheng’s result to obtain two further properties, which consider both vertex and edge faults, as follows: (1) Every fault-free edge of [Formula: see text] lies on a fault-free cycle of every even length from [Formula: see text] to [Formula: see text] if [Formula: see text], where [Formula: see text]; (2) Every fault-free edge of [Formula: see text] lies on a fault-free cycle of every odd length from [Formula: see text] to [Formula: see text] if [Formula: see text], where [Formula: see text] is even.
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Wu, Jianing, and Shaoze Yan. "Fault Severity Evaluation and Improvement Design for Mechanical Systems Using the Fault Injection Technique and Gini Concordance Measure." Mathematical Problems in Engineering 2014 (2014): 1–20. http://dx.doi.org/10.1155/2014/416048.
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A new fault injection and Gini concordance based method has been developed for fault severity analysis for multibody mechanical systems concerning their dynamic properties. The fault tree analysis (FTA) is employed to roughly identify the faults needed to be considered. According to constitution of the mechanical system, the dynamic properties can be achieved by solving the equations that include many types of faults which are injected by using the fault injection technique. Then, the Gini concordance is used to measure the correspondence between the performance with faults and under normal operation thereby providing useful hints of severity ranking in subsystems for reliability design. One numerical example and a series of experiments are provided to illustrate the application of the new method. The results indicate that the proposed method can accurately model the faults and receive the correct information of fault severity. Some strategies are also proposed for reliability improvement of the spacecraft solar array.
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Zhu, Qixin, Kaihong Lu, and Yonghong Zhu. "H∞ Guaranteed Cost Fault-Tolerant Control of Double-Fault Networked Control Systems: Piecewise Delay Method." Mathematical Problems in Engineering 2019 (January 3, 2019): 1–19. http://dx.doi.org/10.1155/2019/6348727.
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The term double-fault networked control system means that sensor faults and actuator faults may occur simultaneously in networked control systems. The issues of modelling and an H∞ guaranteed cost fault-tolerant control in a piecewise delay method for double-fault networked control systems are investigated. The time-varying properties of sensor faults and actuator faults are modelled as two time-varying and bounded parameters. Based on the linear matrix inequality (LMI) approach, an H∞ guaranteed cost fault-tolerant controller in a piecewise delay method is proposed to guarantee the reliability and stability for the double-fault networked control systems. Simulations are included to demonstrate the theoretical results of the proposed method.
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Zhao, Kai, Xiaorong Li, Chuanliang Yan, Yongcun Feng, Liangbin Dou, and Jing Li. "A New Approach To Evaluate Fault-Sliding Potential With Reservoir Depletion." SPE Journal 24, no. 05 (January 28, 2019): 2320–34. http://dx.doi.org/10.2118/194197-pa.
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Summary Fault reactivation caused by reservoir depletion has been an important issue faced by the oil and gas industry. Traditional views suggest that with reservoir depletion, only normal faults can be activated and fault stability either monotonically decreases or increases, which are not consistent with field observations. In this paper, a fault–sliding–potential (FSP) model was developed to analyze fault stability during reservoir depletion for different types of faults. The evolution trend of fault stability with reservoir depletion and the corresponding judging criteria were obtained by calculating the derivatives of FSP. The influences of reservoir depletion on nonsealing and sealing faults were investigated. Case studies were performed to analyze FSP for different types of nonsealing and sealing faults with different fault properties and attitudes. The results show that reverse and strike faults might also be reactivated with reservoir depletion. The fault stability might not monotonically decrease or increase; instead, four evolution patterns of fault stability might occur, with reservoir depletion dependent on the parameters of the faults. Reservoir depletion usually leads to a higher sliding risk for sealing faults than for nonsealing faults. The results also indicate that fault stability is a strong function of fault attitudes, including the dip and strike of the fault.
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Jiang, Jianguo, and Zepeng Zhang. "Properties on Bearing Fault Diagnosis of Water Injection Motor." Scientific Journal of Technology 4, no. 6 (June 20, 2022): 26–33. http://dx.doi.org/10.54691/sjt.v4i6.878.
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Water injection motor in western Daqing Oilfield is the key equipment of water injection to the oil field. Due to the great pressure of water injection to the oil field, the water injection motor is often overloaded and runs at high speed, so that the rolling bearing of the motor is worn, deformed and other faults. In order to detect the small faults that are not easy to detect in the early stage of the motor bearing, this paper proposes a method combining variational mode decomposition (VMD) and fast spectral kurtosis. The optimal number of modes is determined by correlation and energy ratio. The fast spectral kurtosis operation is carried out on the modes with large kurtosis. The fault signal is enveloped and decomposed by the optimal filter parameters. The experimental results show that the algorithm can successfully identify the rolling bearing fault of water injection motor and determine the fault location.
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Frery, Emanuelle, Laurent Langhi, Julian Strand, and Jeffrey Shragge. "Seismic modelling of fault zones." APPEA Journal 56, no. 2 (2016): 599. http://dx.doi.org/10.1071/aj15105.
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While faults have long been known as primary pathways for fluid migration in sedimentary basins, recent work highlights the importance of fault zone internal architecture, lateral variation, transmissivity, and impact on migration and trapping. The impacts of fault zone architecture and properties on seismic images are investigated to facilitate accurately mapped fault zones, and to predict subseismic flow properties and sealing potential. A wedge-type fault model with a main fault and a synthetic fault displacing a typical North West Shelf siliciclastic succession is used to replicate the geometrical components of a seismic-scale fault. Elastic properties are derived from rock physics models, which are used in a 2D elastic modelling algorithm to produce realistic marine seismic acquisition geometry. These data were subsequently input into a 2D prestack (one-way wave-equation) migration code to produce an interpretable seismic image. Base-case elastic properties are systematically varied; modelling focuses on gouge properties, fractured fault zone material, the sandstone Vp/Vs relationship, and shale-sand velocity contrast. The workflow from geological model building to elastic property substitution and forward seismic modelling is extremely quick and versatile, allowing testing of a wide range of scenarios. So far this approach has yielded valuable insights into internal fault property prediction and interpretation of the fault zone in traditional post-stack seismic datasets. Implications for processing workflow and attenuation of fault shadows are also expected.
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Cappa, Frédéric, Marco Maria Scuderi, Cristiano Collettini, Yves Guglielmi, and Jean-Philippe Avouac. "Stabilization of fault slip by fluid injection in the laboratory and in situ." Science Advances 5, no. 3 (March 2019): eaau4065. http://dx.doi.org/10.1126/sciadv.aau4065.
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Faults can slip seismically or aseismically depending on their hydromechanical properties, which can be measured in the laboratory. Here, we demonstrate that fault slip induced by fluid injection in a natural fault at the decametric scale is quantitatively consistent with fault slip and frictional properties measured in the laboratory. The increase in fluid pressure first induces accelerating aseismic creep and fault opening. As the fluid pressure increases further, friction becomes mainly rate strengthening, favoring aseismic slip. Our study reveals how coupling between fault slip and fluid flow promotes stable fault creep during fluid injection. Seismicity is most probably triggered indirectly by the fluid injection due to loading of nonpressurized fault patches by aseismic creep.
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Vandris, Evstratios, and Gerald Sobelman. "Switch-level Differential Fault Simulation of MOS VLSI Circuits." VLSI Design 4, no. 3 (January 1, 1996): 217–29. http://dx.doi.org/10.1155/1996/34084.
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A new switch-level fault simulation method for MOS circuits is presented that combines compiled switch-level simulation techniques and functional fault modeling of transistor faults with the new fault simulation algorithm of differential fault simulation. The fault simulator models both node stuck-at-0, stuck-at-1 faults and transistor stuck-on, stuck-open faults. Prior to simulation, the switch-level circuit components are compiled into functional models. The effect of transistor faults on the function of the circuit components is modeled by functional fault models that execute very fast during simulation. Every compiled circuit component is assigned a dominance attribute, which abstracts relative strength information in the circuit. Dominance is used during simulation to resolve the X-state due to fighting pull-up and pull-down transistor paths and also to deduce transistor fault detectability and fault equivalencies prior to simulation. The differential fault simulation algorithm developed for gate-level circuits is adapted for use at the switch-level. Differential fault simulation provides excellent performance with minimum memory requirements, although it incurs a higher overhead at the switch-level than at the gate-level due to the dynamic memory properties of MOS circuits.
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Chen, Xinglong, Peng Qin, Yongyi Chen, Jianjian Zhao, Wenhao Li, Yao Mao, and Tao Zhao. "Inter-Turn Short Circuit Fault Diagnosis of PMSM." Electronics 11, no. 10 (May 14, 2022): 1576. http://dx.doi.org/10.3390/electronics11101576.
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Permanent Magnet Synchronous Motor (PMSM) is widely used due to its advantages of high power density, high efficiency and so on. In order to ensure the reliability of a PMSM system, it is extremely vital to accurately diagnose the incipient faults. In this paper, a variety of optimization algorithms are utilized to realize the diagnosis of the faulty position and severity of the inter-turn short-circuit (ITSC) fault, which is one of the most destructive and frequent faults in PMSM. Compared with the existing research results gained by particle swarm optimization algorithms, in this paper, the methods using other optimization algorithms incorporating genetic algorithm, whale optimization algorithm and stochastic parallel gradient descent algorithm (SPGD) can acquire more stable and precise results. In particular, the method based on SPGD can obtain the most desirable performance among the methods mentioned above; that is, the relative error of short-circuit turns ratio is approximately as low as 0.03%. In addition, in the case of asymmetric input three-phase voltage and with the adverse impact of high-order harmonics at different load moments, the fault diagnosis method based on SPGD still maintains relatively satisfactory properties. Finally, the verification on the actual PMSM platform demonstrates that the SPGD can still diagnose the faulty severity.
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Wang, Wei, Lanyu Xu, and Rong Yao. "Numerical Simulation on Stick-Slip Properties of Fault Considering Loading Velocity." Journal of Physics: Conference Series 2285, no. 1 (June 1, 2022): 012014. http://dx.doi.org/10.1088/1742-6596/2285/1/012014.
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Abstract The stick-slip of faults is one of the main causes of earthquakes in tectonic earthquake. The traditional interface element model cannot simulate the stick-slip phenomenon in the fault sliding although it can simulate the change of stress field of the rock mass by the because of the fault. Based on the interface element in FLAC(Fast Lagrangian Analysis Continua), the friction law of the interface element of the fault is redeveloped by using the Fish language, which is embedded in the FLAC, and the rate-state dependent friction law is introduced into the interface element. The effects of loading rate on rock friction properties were investigated and compared with previous experimental results. Well consistency was obtained to further study the development and evolution of fault slip.
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Parzinger, Michael, Lucia Hanfstaengl, Ferdinand Sigg, Uli Spindler, Ulrich Wellisch, and Markus Wirnsberger. "Residual Analysis of Predictive Modelling Data for Automated Fault Detection in Building’s Heating, Ventilation and Air Conditioning Systems." Sustainability 12, no. 17 (August 20, 2020): 6758. http://dx.doi.org/10.3390/su12176758.
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Faults in Heating, Ventilation and Air Conditioning (HVAC) systems affect the energy efficiency of buildings. To date, there rarely exist methods to detect and diagnose faults during the operation of buildings that are both cost-effective and sufficient accurate. This study presents a method that uses artificial intelligence to automate the detection of faults in HVAC systems. The automated fault detection is based on a residual analysis of the predicted total heating power and the actual total heating power using an algorithm that aims to find an optimal decision rule for the determination of faults. The data for this study was provided by a detailed simulation of a residential case study house. A machine learning model and an ARX model predict the building operation. The model for fault detection is trained on a fault-free data set and then tested with a faulty operation. The algorithm for an optimal decision rule uses various statistical tests of residual properties such as the Sign Test, the Turning Point Test, the Box-Pierce Test and the Bartels-Rank Test. The results show that it is possible to predict faults for both known faults and unknown faults. The challenge is to find the optimal algorithm to determine the best decision rules. In the outlook of this study, further methods are presented that aim to solve this challenge.
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Du, Chuan, Qingzhi Zhang, and Shuai Cao. "A Smart Fault-Tackling Strategy Based on PFTE for AC Three-Phase-to-Ground Faults in the Multi-Terminal HVDC Wind Power Integration System: Further Foundings." Energies 15, no. 3 (January 21, 2022): 768. http://dx.doi.org/10.3390/en15030768.
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This paper describes a smart fault tackling strategy based on power flow transfer entropy (PFTE) for AC three-phase-to-ground (TPG) faults in the multi-terminal HVDC (MTDC) wind power integration system. The fault characteristics and transient energy transfer of different positions and properties are analyzed. Then, a double integral discrimination method based on PFTE is proposed to further distinguish the fault property. Considering the power flow balance, an adaptive coordination strategy of wind farms and energy dissipation resistors is proposed to deal with different AC faults. Finally, a smart fault-tackling strategy based on PFTE for AC three-phase-to-ground (TPG) faults in the MTDC wind power integration system is proposed. Under the proposed smart fault-tackling strategy, the MTDC wind power integration system achieves uninterrupted operation during any AC TPG fault at the receiving end. The experiment results confirm the applicability of the proposed fault-tackling strategy.
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Li, Guoyan, Fangyi Li, Haohua Liu, and Dehao Dong. "Fault features analysis of a compound planetary gear set with damaged planet gears." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 9 (April 27, 2017): 1586–604. http://dx.doi.org/10.1177/0954406217705906.
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The fault properties of compound planetary gear set are much more complicated than the simple planetary gear set. A damaged planet will induce two periodic transient impulses in the raw signals and generates modulation sidebands around the mesh harmonics. This paper aims to investigate the fault properties of a compound planetary gear set in damaged planet conditions. A dynamic model is proposed to simulate the vibration signals. The time interval between the fault-induced close impulses in the time domain is used as a significant feature to locate the faulty planet. Considering the phase relations, the time-varying mesh stiffness is obtained. Then, the fault properties are demonstrated in the simulation, and the theoretical derivations are experimentally verified.
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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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Worthington, M. H., and J. A. Hudson. "Fault properties from seismicQ." Geophysical Journal International 143, no. 3 (December 2000): 937–44. http://dx.doi.org/10.1046/j.1365-246x.2000.00315.x.
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Karamanos, Ch K., V. G. Karakostas, L. Seeber, E. E. Papadimitriou, and A. A. Kilias. "RECENT SEISMIC ACTIVITY IN CENTRAL GREECE REVEALING LOCAL SEISMOTECTONIC PROPERTIES." Bulletin of the Geological Society of Greece 43, no. 4 (January 25, 2017): 2075. http://dx.doi.org/10.12681/bgsg.11397.
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The December 2008, M=5.2 earthquake occurred in the Voiotikos–Kifissos basin near the town of Amfikleia in Central Greece and was followed by an intense sequence with hundreds of earthquakes. Mainshock source characteristics derived from the recordings of the Greek National Seismological Network are consistent with previous known earthquakes as well as with the current nearly N–S extensional regime. The adequate azimuthal coverage and the calculated time residuals at each seismological station ensure high location accuracy, whereas the stations operated close to the seismic excitations constrained 80% of the focal depths between 8 and 12km. Distances from the mainshock epicenter to the 10 closest seismological stations vary from 15 to 75 km. Hypoinverse and HypoDD were used for locations, and FPFIT was used for fault plane solutions of events with an adequate number of clear first arrivals. The hypocenters and focal mechanisms illuminate a ≈10km–long fault zone striking nearly E–W with oblique normal faulting and a small left lateral component. The Voiotikos–Kifissos basin is bordered in the south by two left–stepping en echelon segments known as the Pavliani fault zone and the Parnassos detachment, which strike NW and dip NE. In our preferred interpretation, the Amfikleia mainshock ruptured a previously recognized south–dipping fault antithetic to the basin border faults. This fault may be associated with the left step on the border fault, which would be releasing if that fault had a sinistral component.
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Kolyukhin, Dmitriy R., Vadim V. Lisitsa, Maxim I. Protasov, Dongfang Qu, Galina V. Reshetova, Jan Tveranger, Vladimir A. Tcheverda, and Dmitry M. Vishnevsky. "Seismic imaging and statistical analysis of fault facies models." Interpretation 5, no. 4 (November 30, 2017): SP71—SP82. http://dx.doi.org/10.1190/int-2016-0202.1.
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Interpretation of seismic responses from subsurface fault zones is hampered by the fact that the geologic structure and property distributions of fault zones can generally not be directly observed. This shortcoming curtails the use of seismic data for characterizing internal structure and properties of fault zones, and it has instead promoted the use of interpretation techniques that tend to simplify actual structural complexity by rendering faults as lines and planes rather than volumes of deformed rock. Facilitating the correlation of rock properties and seismic images of fault zones would enable active use of these images for interpreting fault zones, which in turn would improve our ability to assess the impact of fault zones on subsurface fluid flow. We use a combination of 3D fault zone models, based on empirical data and 2D forward seismic modeling to investigate the link between fault zone properties and seismic response. A comparison of spatial statistics from the geologic models and the seismic images was carried out to study how well seismic images render the modeled geologic features. Our results indicate the feasibility of extracting information about fault zone structure from seismic data by the methods used.
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Grant, Neil T. "Stochastic modelling of fault gouge zones: implications for fault seal analysis." Geological Society, London, Special Publications 496, no. 1 (August 7, 2019): 163–97. http://dx.doi.org/10.1144/sp496-2018-135.
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AbstractFault zones are complex, and show considerable variability in both structure and the distribution of associated fault rocks within the fault core: the zone that localizes most strain and displacement. It is the fault-core gouge zone and associated slip surfaces which provide the cross-fault seal when permeable layers are juxtaposed. Predicting the sealing properties of fault gouge zones is difficult but often required when evaluating faults in exploration prospects. A stochastic modelling approach is described to help better understand the compositional controls on fault gouge seal potential. The model is populated with a random assemblage of four fault rock components: shale smears, shaly gouge, cataclastic gouge and low-strain host-rock lenses. Harmonic averaging of permeability and arithmetic averaging of Vshale are then used to upscale the properties, and to propose a simple permeability–Vshale model for fault rocks. Practical application of the model is discussed by developing an empirical link between standard well-log data and associated fault rock effective permeability. This new approach has the potential to offer a simple well-log-based fault seal model. The utility of the model is demonstrated with a case study, comparing the results to those generated using other published techniques.
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Vemuri, Arun T., and Marios M. Polycarpou. "A methodology for fault diagnosis in robotic systems using neural networks." Robotica 22, no. 4 (August 2004): 419–38. http://dx.doi.org/10.1017/s0263574703005204.
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Fault diagnosis plays an important role in the operation of modern robotic systems. A number of researchers have proposed fault diagnosis architectures for robotic manipulators using the model-based analytical redundancy approach. One of the key issues in the design of such fault diagnosis schemes is the effect of modeling uncertainties on their performance. This paper investigates the problem of fault diagnosis in rigid-link robotic manipulators with modeling uncertainties. A learning architecture with sigmoidal neural networks is used to monitor the robotic system for off-nominal behavior due to faults. The robustness, sensitivity, missed detection and stability properties of the fault diagnosis scheme are rigorously established. Simulation examples are presented to illustrate the ability of the neural network based robust fault diagnosis scheme to detect and accommodate faults in a two-link robotic manipulator.
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Liang, Haiying, Chencheng Zhao, Yungao Chen, Yang Liu, and Yulai Zhao. "The Improved WNOFRFs Feature Extraction Method and Its Application to Quantitative Diagnosis for Cracked Rotor Systems." Sensors 22, no. 5 (March 2, 2022): 1936. http://dx.doi.org/10.3390/s22051936.
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During its operation, a rotor system can be exposed to multiple faults, such as rub-impact, misalignment, cracks and unbalancing. When a crack fault occurs on the rotor shaft, the vibration response signals contain some nonlinear components that are considerably tougher to be extracted through some linear diagnosis methods. By combining the Nonlinear Output Frequency Response Functions weighted contribution rate (WNOFRFs) and Kullback–Leibler (KL) divergence, a novel fault diagnosis method of improved WNOFRFs is proposed. In this method, an index, improved optimal WNOFRFs (IOW), is defined to represent the nonlinearity of the faulty rotor system. This method has been tested through the finite element model of a cracked rotor system and then verified experimentally at the shaft crack detection test bench. The results from the simulation and experiment verified that the proposed method is applicable and effective for cracked rotor systems. The IOW indicator shows high sensitivity to crack faults and can comprehensively represent the nonlinear properties of the system. It can also quantitatively detect the crack fault, and the relationship between the values of IOW and the relative depth of the crack is approximately positively proportional. The proposed method can precisely and quantitatively diagnose crack faults in a rotor system.
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He, Yu-Ling, Zhi-Jie Zhang, Xiao-Long Wang, Peng Gao, David Gerada, Chris Gerada, and Gaurang Vakil. "Impact of Single and Combined Faults Composed of Rotor Eccentricity and Stator Interturn Short Circuit on Electromagnetic Torque Ripples in Synchronous Generator." Complexity 2020 (March 25, 2020): 1–21. http://dx.doi.org/10.1155/2020/8535421.
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In order to comprehensively study and identify the electromagnetic torque (EMT) difference among the single static air-gap eccentricity (SAGE) fault, the single stator interturn short circuit fault (SISC), and the combined fault composed of these two, this article investigates the EMT ripple properties due to the mentioned three faults. Different from other studies, this paper considers not only the effect of the single fault types but also the impact of the single fault combinations on the EMT ripple characteristics. Detailed EMT expressions for each fault are firstly derived on the basis of the magnetic flux density (MFD) analysis. Then, finite element calculation and experimental study on a CS-5 prototype generator with two poles at 3000 rpm, which is specifically designed and manufactured ourselves, are carried out to validate the analysis result. It is found that the three faults will induce different ripple components in EMT. The combined faults have the most intensive impact sensitivity on the EMT ripples, while the single SAGE fault ranks the last in the impact effect.
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Pu, RenHai, KunBai Li, Machao Dong, ZiCheng Cao, and Pengye Xu. "The 3D seismic characteristics and significance of the strike-slip faults in the Tazhong area (Tarim Basin, China)." Interpretation 7, no. 1 (February 1, 2019): T1—T19. http://dx.doi.org/10.1190/int-2016-0135.1.
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The eastern part of Tazhong area in the Tarim Basin consists of three sets of vertical strike-slip faults oriented in north–northeast (36°azimuth), east–northeast (68° azimuth), and west–northwest (126°azimuth) directions that cut the strata from Cambrian to Carboniferous. The fault belts indicate significant horizon upwarp and downwarp deformations and variations in their stratigraphic thickness on seismic profiles. Through detailed interpretation of the 3D seismic data, we consider that these phenomena reflect the different stress properties and active stages of the faults. The horizon upwarp and downwarp within the fault belts correlated respectively to the decrease and increase in stratigraphic thickness within the fault belts in comparison to the coeval counterpart of the bilateral fault blocks. For the same fault, different stratigraphic intervals express different types of horizon deformation and thickness changes. The horizon downwarp and the contemporaneous stratigraphic thickening inside the fault belts suggest the transtensional actions of the fault. The horizon upwarp and the contemporaneous thinning within the fault belts suggest transpressional actions of the fault. Based on this, we inferred the active periods of the three sets of strike-slip faults. The north–northeast-striking faults were formed in the late Ordovician Sangtamu Formation. This set of faults experienced four stages, i.e., sinistral transpression, sinistral transtension, static, and transtension. The east–northeast and west–northwest-striking faults initiated in the mid-Cambrian period as coupled transtension. Activity ceased in the west–northwest faults after the mid-Cambrian and in the east–northeast faults during the late Ordovician. The three sets of strike-slip faults all affect the formation of the hydrothermal dissolution reservoirs that are distributed in the Ordovician carbonate rocks.
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Riegel, Hannah, Miller Zambrano, Fabrizio Balsamo, Luca Mattioni, and Emanuele Tondi. "Petrophysical Properties and Microstructural Analysis of Faulted Heterolithic Packages: A Case Study from Miocene Turbidite Successions, Italy." Geofluids 2019 (June 2, 2019): 1–23. http://dx.doi.org/10.1155/2019/9582359.
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Geofluid reservoirs located in heterolithic successions (e.g., turbidites) can be affected by vertical and lateral compartmentalization due to interbedded fine-grained facies (i.e., shale, siltstones) and the presence of faults, respectively. A fault can behave as a conduit or barrier to fluid flow depending on its architecture and the individual hydraulic behavior of its components (i.e., fault core, damage zone). The fault core, normally composed by fault rock or smeared clay material, commonly acts as a flow inhibitor across the fault. Fault-related fractures (macro- and microscopic) in the damage zone generally increase the permeability parallel to the fault, except when they are cemented or filled with gouge material. Although macrofractures (which define the fracture porosity) dominate fluid flow, the matrix porosity (including microfractures) begins to have a more important role in fluid flow as the aperture of macrofractures is occluded, particularly at greater depth. This study investigates the variation in matrix permeability in fault zones hosted in heterolithic successions due to fault architecture and stratigraphy of host rock (i.e., sand-rich turbidites). Two key areas of well-exposed, faulted Miocene turbidites located in central and southern Italy were selected. For this study, six separate fault zones of varying offset were chosen. Each impacts heterolithic successions that formed under similar tectonic conditions and burial depths. Across the selected fault zones, an extensive petrophysical analysis was done in the field and laboratory, through air permeameter measurements, thin section, and synchrotron analysis in both host rock, damage zone, and fault core. Results suggest that the amount and distribution of clay layers in a heterolithic sequence affects fluid flow across the fault, regardless of fault offset.
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Knai, Tor Anders, and Guillaume Lescoffit. "Efficient handling of fault properties using the Juxtaposition Table Method." Geological Society, London, Special Publications 496, no. 1 (2020): 199–207. http://dx.doi.org/10.1144/sp496-2018-192.
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AbstractFaults are known to affect the way that fluids can flow in clastic oil and gas reservoirs. Fault barriers either stop fluids from passing across or they restrict and direct the fluid flow, creating static or dynamic reservoir compartments. Representing the effect of these barriers in reservoir models is key to establishing optimal plans for reservoir drainage, field development and production.Fault property modelling is challenging, however, as observations of faults in nature show a rapid and unpredictable variation in fault rock content and architecture. Fault representation in reservoir models will necessarily be a simplification, and it is important that the uncertainty ranges are captured in the input parameters. History matching also requires flexibility in order to handle a wide variety of data and observations.The Juxtaposition Table Method is a new technique that efficiently handles all relevant geological and production data in fault property modelling. The method provides a common interface that is easy to relate to for all petroleum technology disciplines, and allows a close cooperation between the geologist and reservoir engineer in the process of matching the reservoir model to observed production behaviour. Consequently, the method is well suited to handling fault property modelling in the complete life cycle of oil and gas fields, starting with geological predictions and incorporating knowledge of dynamic reservoir behaviour as production data become available.
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Bogusz, Piotr, Mariusz Korkosz, Adam Powrózek, Jan Prokop, and Piotr Wygonik. "Research of influence of open-winding faults on properties of brushless permanent magnets motor." Open Physics 15, no. 1 (December 29, 2017): 959–64. http://dx.doi.org/10.1515/phys-2017-0118.
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AbstractThe paper presents an analysis of influence of selected fault states on properties of brushless DC motor with permanent magnets. The subject of study was a BLDC motor designed by the authors for unmanned aerial vehicle hybrid drive. Four parallel branches per each phase were provided in the discussed 3-phase motor. After open-winding fault in single or few parallel branches, a further operation of the motor can be continued. Waveforms of currents, voltages and electromagnetic torque were determined in discussed fault states based on the developed mathematical and simulation models. Laboratory test results concerning an influence of open-windings faults in parallel branches on properties of BLDC motor were presented.
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Jia, Ru, Bo Liu, Xiaofei Fu, Lei Gong, and Zhida Liu. "Transformation Mechanism of a Fault and Its Associated Microstructures in Low-Porosity Rocks: A Case Study of the Tanan Depression in the Hailar-Tamtsag Basin." Journal of Marine Science and Engineering 7, no. 9 (August 24, 2019): 286. http://dx.doi.org/10.3390/jmse7090286.
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Faults have complex internal structures, which can be divided into the fault core and the damaged zone. During the fault formation process, the damaged zone will develop a large number of fractures cross cutting the adjacent host rocks, where the size and density of fractures would decrease as a function of distance from the fault core. Statistics show that compared with the host rocks, the rock’s secondary porosity may significantly get improved until it is 5%–10% higher than the host rock’s, and the permeability could be increased from zero to six orders of magnitude higher where fractures are developed. Based on the distribution of the fault core and damaged zone, we established an idealized geologic model to analyze the influence of the fault associated microstructures on the fluid flow efficiency. The results demonstrated that the reservoir property will be effectively improved when the fractures are developed to a certain magnitude, which will provide an advantageous conduit for fluid flow. The physical properties of wells are significantly different between the reservoirs transformed by the fractures and the reservoirs that have not been affected. The reservoir unit near faults has been modified by the associated fractures improving the reservoir quality. In addition, the portions of the reservoir farther from the fault core are less influenced and retain their initial poor characteristics. In order to evaluate the enhanced reservoir properties caused by faults and associated fractures, we performed statistical analysis of valid porosity ratio of the Nantun reservoirs as a function of the distance from 49 wells to faults in the research area. The results of this study demonstrated that connected fractures enhance the properties of the reservoirs and there is a distinct range that separates oil producing wells and water producing ones. This phenomenon verifies that faults are important and must be considered carefully during the exploration and production for hydrocarbon to provide higher quality reservoirs.
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Treffeisen, Torben, and Andreas Henk. "Elastic and Frictional Properties of Fault Zones in Reservoir-Scale Hydro-Mechanical Models—A Sensitivity Study." Energies 13, no. 18 (September 4, 2020): 4606. http://dx.doi.org/10.3390/en13184606.
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The proper representation of faults in coupled hydro-mechanical reservoir models is challenged, among others, by the difference between the small-scale heterogeneity of fault zones observed in nature and the large size of the calculation cells in numerical simulations. In the present study we use a generic finite element (FE) model with a volumetric fault zone description to examine what effect the corresponding upscaled material parameters have on pore pressures, stresses, and deformation within and surrounding the fault zone. Such a sensitivity study is important as the usually poor data base regarding specific hydro-mechanical fault properties as well as the upscaling process introduces uncertainties, whose impact on the modelling results is otherwise difficult to assess. Altogether, 87 scenarios with different elastic and plastic parameter combinations were studied. Numerical modelling results indicate that Young’s modulus and cohesion assigned to the fault zone have the strongest influence on the stress and strain perturbations, both in absolute numbers as well as regarding the spatial extent. Angle of internal friction has only a minor and Poisson’s ratio of the fault zone a negligible impact. Finally, some general recommendations concerning the choice of mechanical fault zone properties for reservoir-scale hydro-mechanical models are given.
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Zheng, Yun, Cong Xin Chen, Xi Xi Zhu, Xiu Min Liu, and Guan Wen Cheng. "Stability Analysis of Open-Pit Slope Containing a Fault Utilizing UDEC." Applied Mechanics and Materials 444-445 (October 2013): 1204–10. http://dx.doi.org/10.4028/www.scientific.net/amm.444-445.1204.
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Faults are the commonly encountered large geological discontinuities in hard rock masses, many severe open pit slope failures are found to be closely associated with the faults presence nearby. Open-pit slope takes shape gradually as a rock unloading process accompanied by geostress redistribution, especially in a slope containing a fault. The finite difference code (UDEC) was employed as the analytical method in this paper and coulomb slip model was utilized to describe the properties of fault provided by UDEC. Parametric analysis has identified both the fault dips and fault locations relative to the open pit slope to be really critical for the open pit slope stability. The relationship of crest displacements, safety factor varying with these fault parameters was established. The distribution of plastic zone and displacement was graphically presented and the mechanisms such effects were discussed. These results offer a guideline in support design for an open-pit slope containing a fault.
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Soliva, Roger, Antonio Benedicto, Pierre Vergély, and Thierry Rives. "Mechanical control of a lithological alternation on normal fault morphology, growth and reactivation." Bulletin de la Société Géologique de France 176, no. 4 (July 1, 2005): 329–42. http://dx.doi.org/10.2113/176.4.329.
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Abstract This paper presents an analysis of the control of lithological variation on normal fault morphology, growth and reactivation. We study a normal fault population contained within an inter-bedded sequence of marly-limestones and clay rich layers. The analysis of cross sectional and bedding plane exposure of faults reveals that the plastic clay layers act as barriers to vertical fault propagation. Only the long vertically restricted normal faults (i.e. confined between two clay layers) are later reactivated and show extensional-shear mode of deformation. The likelihood of reactivation of the faults was probably favoured by the small plastic strength of the clay rich layers. We discuss the extensional-shear mode in terms of structural context, reactivation and rock rigidity. Displacement profile analysis of only isolated non-reactivated faults allows us to distinguish the faults mechanically influenced by the rheological discontinuities from those that are contained within the same lithological unit. Using both cross-sectional observations and displacement-length data of the fault population we estimate the average aspect ratio (length/height ~ 2) of the faults contained within the same lithological unit. A 3-D displacement-length scaling law that integrates post yield fracture mechanics (PYFM) and the principal fault dimensions (length and height) reveals the importance of the low rigidity of the marly-limestone on the displacement of the faults contained into a same lithological unit. A comparison of our displacement-length data with those compiled from the literature suggests that the displacement-length variability is strongly related to the rock mechanical properties and contrasts in layered rocks. The bulk of our analysis, based on field observations and theory, shows that: (i) fault shape, (ii) fault ability to be reactivated, (iii) shear mode, and (iv) displacement-length values are strongly sensitive to the lithological contrasts, and are therefore dependent on the fault dimension relative to the thicknesses of the sedimentary bodies. Therefore, regardless the variety of fault initiation processes, our analysis confirms that both fault morphology and fault growth are not self similar in heterogeneous layered rocks from centimetre to kilometre scale.
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Qu, Ruotong, Bin Jiang, and Yuehua Cheng. "Research on the Diagnosability of a Satellite Attitude Determination System on a Fault Information Manifold." Applied Sciences 12, no. 24 (December 14, 2022): 12835. http://dx.doi.org/10.3390/app122412835.
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In this paper, a new method for fault diagnosability research based on information geometry is proposed. The problem of the diagnosability evaluation of dynamic system faults is transformed into a distance calculation problem on a manifold. The Fisher information distance is used to realize a quantitative judgment of diagnosability, and a quantitative evaluation index of the fault diagnosability of a satellite attitude determination system is designed. This includes a fault detectability index and a fault isolability index. The validity and superiority of the new indexes are verified through a mathematical simulation. In addition, the fault information is visually presented by the geodesics of the fault manifold, and the properties and behavior of the fault are mined and analyzed on the fault information manifold, which lays a foundation for further exploration of fault information through geometric methods.
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Feng, Zhipeng, and Fulei Chu. "Cyclostationary Analysis for Gearbox and Bearing Fault Diagnosis." Shock and Vibration 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/542472.
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Gearbox and rolling element bearing vibration signals feature modulation, thus being cyclostationary. Therefore, the cyclic correlation and cyclic spectrum are suited to analyze their modulation characteristics and thereby extract gearbox and bearing fault symptoms. In order to thoroughly understand the cyclostationarity of gearbox and bearing vibrations, the explicit expressions of cyclic correlation and cyclic spectrum for amplitude modulation and frequency modulation (AM-FM) signals are derived, and their properties are summarized. The theoretical derivations are illustrated and validated by gearbox and bearing experimental signal analyses. The modulation characteristics caused by gearbox and bearing faults are extracted. In faulty gearbox and bearing cases, more peaks appear in cyclic correlation slice of 0 lag and cyclic spectrum, than in healthy cases. The gear and bearing faults are detected by checking the presence or monitoring the magnitude change of peaks in cyclic correlation and cyclic spectrum and are located according to the peak cyclic frequency locations or sideband frequency spacing.
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Dyer, Hilary, David Amitrano, and Anne-Marie Boullier. "Scaling properties of fault rocks." Journal of Structural Geology 45 (December 2012): 125–36. http://dx.doi.org/10.1016/j.jsg.2012.06.016.
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KUO, CHE-NAN. "Embedding Every Cycle in Conditionally Faulty Folded Hypercubes." Journal of Interconnection Networks 16, no. 03n04 (September 2016): 1650007. http://dx.doi.org/10.1142/s0219265916500079.
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A network is said to be conditionally faulty if its every vertex is incident to at least g fault-free neighbors, where g≥1. An n-dimensional folded hypercube FQn is a well-known variation of an n-dimensional hypercube Qn, which can be constructed from Qn by adding an edge to every pair of vertices with complementary addresses. In this paper, we define that a network is said to be g-conditionally faulty if its every vertex is incident to at least g fault-free neighbors, and let FFv (respectively, FFe) denote the set of faulty vertices (respectively, faulty edges) in FQn. Then, we consider for the cycles embedding properties in FQn−FFv−FFe with 4-conditionally faulty, as follows: (1) For n≥3, FQn−FFv−FFe contains a fault-free cycle of every even length from 4 to 2n−2|FFv|, where |FFn|+|FFe| ≤ 2n−5; (2) For even n≥4, FQn−FFv−FFe contains a fault-free cycle of every odd length from n+1 to 2n−2|FFv|−1, where |FFv|+|FFe| ≤ 2n−5.
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Fang, Shaoji, and Mogens Blanke. "Fault monitoring and fault recovery control for position-moored vessels." International Journal of Applied Mathematics and Computer Science 21, no. 3 (September 1, 2011): 467–78. http://dx.doi.org/10.2478/v10006-011-0035-9.
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Fault monitoring and fault recovery control for position-moored vessels This paper addresses fault-tolerant control for position mooring of a shuttle or floating production storage and offloading vessels. A complete framework for fault diagnosis is presented. A loss of a sub-sea mooring line buoyancy element and line breakage are given particular attention, since such failures might cause high-risk abortion of an oil-loading operation. With significant drift forces from waves, non-Gaussian elements dominate forces and the residuals designed for fault diagnosis. Hypothesis testing is designed using dedicated change detection for the type of distribution encountered. A new position recovery algorithm is proposed as a means of fault accommodation in order to keep the mooring system in a safe state, despite faults. The position control is shown to be capable of accommodating serious failures and preventing breakage of a mooring line, or a loss of a buoyancy element, from causing subsequent failures. Properties of the detection and fault-tolerant control algorithms are demonstrated by high fidelity simulations.
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Venkata and Rao. "Fault Detection of a Flow Control Valve Using Vibration Analysis and Support Vector Machine." Electronics 8, no. 10 (September 20, 2019): 1062. http://dx.doi.org/10.3390/electronics8101062.
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A control valve plays a very significant role in the stable and efficient working of a control loop for any process. In a fluid flow process, the probability of failure of a control valve may increase for many reasons pertaining to a flow process such as high pressures at the inlet, different properties of the liquid flowing through the pipe, mechanical issue related to a control valve, ageing, etc. A method to detect faults in the valve can lead to better stability of the control loop. In the proposed work, a technique is developed to determine the fault in a pneumatic control valve by analyzing the vibration data at the outlet of the valve. The fault diagnosis of the valve is carried out by analyzing the change in vibration of the pipe due to the change in flow pattern induced by the control valve. The faults being considered are inflow and insufficient supply pressure faults. Vibration data obtained is processed using a signal processing technique like amplification, Fourier transform, etc. The support vector machine (SVM) algorithm is used to classify the vibration data into two classes, one normal and the other faulty. The designed algorithm is trained to identify faults and subjected to test with a practical setup; test results show an accuracy of 97%.
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Khedher, Atef, Ilyes Elleuch, and Kamal BenOthman. "Adaptive Proportional Integral Observer Design for Interval Type 2 Takagi–Sugeno Fuzzy Systems." Mathematical Problems in Engineering 2021 (July 15, 2021): 1–13. http://dx.doi.org/10.1155/2021/5317391.
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In this paper, the problem of fault estimation in systems described by Takagi–Sugeno fuzzy systems is studied. A proportional integral observer is conceived in order to reconstruct state and faults which can affect the studied system. Proportional integral observer can easily estimate actuator faults which are assimilated to be as unknown inputs. In order to estimate actuator and sensor faults, a mathematical transformation is used to conceive an augmented system, in which the initial sensor fault appears as an unknown input. Considering the augmented state, it is possible to conceive an adaptive observer which is able to estimate the whole state and faults. The noise effect on the state and fault estimation is also minimized in this study, which provides some robustness properties to the proposed observer. The proportional integral observer is conceived for nonlinear systems described by Takagi–Sugeno fuzzy models.
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Du, Hui, and Feng Gao. "Fault tolerance properties and motion planning of a six-legged robot with multiple faults." Robotica 35, no. 6 (April 12, 2016): 1397–414. http://dx.doi.org/10.1017/s0263574716000175.
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SUMMARYThe six-legged robot Octopus is designed for nuclear disaster relief missions. When the robot suffers from failures, its performance can be significantly affected. Thus, fault tolerance is essential for walking and operating in environments inaccessible to humans. The current fault-tolerant gaits for legged robots usually either initially lock the entire broken leg or just abandon the broken leg, but then fail to take full advantage of the normal actuators on the broken leg and add extra constraints. As the number of broken legs increases, the robot will no longer be able to walk using the existing fault-tolerant gaits. To solve this problem, screw theory is used for analyzing the remaining mobility after failure. Based on the analysis, a method of motion planning through fault-tolerant Jacobian matrices, which are linear, is presented. This method can enable the robot to accomplish desired movement using broken legs along with other certain concomitant motions as compensation. Finally, experiments and simulations of multiple faults demonstrate the real effects on the Octopus robot.
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Chen, Zhuoheng, and Quanquan Fu. "A METHOD FOR ESTIMATING FAULT PROPERTIES OF A FAULT POPULATION." Geoinformatics 7, no. 1-2 (1996): 19–22. http://dx.doi.org/10.6010/geoinformatics1990.7.1-2_19.
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Collettini, Cristiano, André Niemeijer, Cecilia Viti, Steven A. F. Smith, and Chris Marone. "Fault structure, frictional properties and mixed-mode fault slip behavior." Earth and Planetary Science Letters 311, no. 3-4 (November 2011): 316–27. http://dx.doi.org/10.1016/j.epsl.2011.09.020.
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Ma, Yuchuan, Guangcai Wang, Rui Yan, Bo Wang, Huaizhong Yu, Chen Yu, Chong Yue, and Yali Wang. "Relationship between Earthquake-Induced Hydrologic Changes and Faults." Water 13, no. 19 (October 8, 2021): 2795. http://dx.doi.org/10.3390/w13192795.
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Hydraulic properties of fault zones are important to understanding the pore pressure development and fault stability. In this work, we examined the relationship between water level changes caused by the 2008 Wenchuan Mw 7.9 earthquake and faults using four wells with the same lithology around the Three Gorges Dam, China. Two of the wells penetrating the fault damage zones recorded sustained water level changes, while the other two wells that are not penetrating any fault damage zones recorded transient water level changes. The phase shift and tidal factor calculated from water level, a proxy of permeability and storage coefficient, revealed that both the permeability and storage coefficient changed in the two wells penetrating the fault damage zones, while the other two wells not penetrating the fault damage zone did not show any change in permeability and storage coefficient. Thus, we tentatively suggest that faults may play an important controlling role on earthquake-induced hydrologic changes because the detrital or clogging components in the fractures may be more easily removed by seismic waves.
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RIEKSTS, BRIAN Q., and JOSE A. VENTURA. "TIME-RELAXED 1-FAULT TOLERANT BROADCAST NETWORKS." Parallel Processing Letters 19, no. 02 (June 2009): 335–53. http://dx.doi.org/10.1142/s0129626409000250.
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In a 1-fault tolerant minimal broadcast network, a node of a network, called the originator, has a message which is to be transmitted to all other nodes of the network in minimum time regardless of the failure of a single communication line. In some instances, it is advantageous to use time-relaxed broadcast networks that require slightly more than the minimum transmission time, but have sparser edge sets. This paper presents a general compounding algorithm to construct sparse, time-relaxed, 1-fault tolerant broadcast networks. In the algorithm, copies of a broadcast network without faults are interconnected with additional edges according to the structure of a 1-fault tolerant broadcast network with two special properties. Both the 1-fault tolerant broadcast network and the broadcast network without faults may be time-relaxed. Computational results show that the algorithm yields sparser networks by allowing additional time units.
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Sun, Shi Guo, Shao Jie Feng, and Jia Hao Lei. "Water-Inrush Mechanism while Fault Zone Secondary Activated in Mining." Advanced Materials Research 524-527 (May 2012): 799–802. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.799.
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As many different size faults in the fully-mechanized sublevel caving mining area overlying rock, undermine the continuity of rock deformation, and the occurrence of different conditions, the impact properties vary widely. This paper studies the impact of faults on the water inrush with specific examples of project, obtained the discontinuous deformation on both sides of fault zone induce the fault zone secondary activate and result in it’s water transmitting ability dramatic increase; with the mining geometry increases, the water flowing-fracture zone height increase and lead to the water conductivity channel of faults connect with rock fracture zone, so as to constitute water inrush channel and likely to cause water inrush accident, so to explore the influence of fault for underground work safety has important theoretical significance and application value.
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Zhao, Hong Shan, Sha Sha Lian, and Ling Shao. "Fault Prediction of Pitch Actuator for Wind Turbines." Applied Mechanics and Materials 721 (December 2014): 397–401. http://dx.doi.org/10.4028/www.scientific.net/amm.721.397.
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Hydraulic pitch-controlled system is one of the components of wind turbines which are frequently prone to faults. Early fault prediction of the pitch control system can improve the operation reliability effectively and reduce the unnecessary loss. Wind turbines suffer much environmental interference; moreover, data-based fault prediction is vulnerable to occur false alarms by the impact of these factors. And it is difficult to implement the fault isolation. So this paper presents a fault prediction method for the pitch-controlled system, which is based on the mathematical model of wind turbines physical properties. The residual root mean square (RMS) is used as residual evaluation function. In the end of the paper, by the simulation using the hydraulic pitch actuator fault as the example, the effectiveness of the proposed fault prediction scheme is verified.