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fault-detection
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Soft error mitigation in cache memories of embedded systems by means of a protected scheme
, Article 2nd Latin-American Symposium on Dependable Computing, LADC 2005, Salvador, 25 October 2005 through 28 October 2005 ; Volume 3747 LNCS , 2005 , Pages 121-130 ; 03029743 (ISSN); 3540295720 (ISBN); 9783540295723 (ISBN) ; Miremadi, S. G ; Sharif University of Technology
2005
Abstract
The size and speed of SRAM caches of embedded systems are increasing in response to demands for higher performance. However, the SRAM caches are vulnerable to soft errors originated from energetic nuclear particles or electrical sources. This paper proposes a new protected cache scheme, which provides high performance as well as high fault detection coverage. In this scheme, the cache space is divided into sets of different sizes. Here, the length of tag fields associated to each set is unique and is different from the other sets. The other remained bits of tags are used for protecting the tag using a fault detection scheme e.g., generalized parity. This leads to protect the cache without...
Fault detection enhancement in cache memories using a high performance placement algorithm
, Article Proceedings - 10th IEEE International On-Line Testing Symposium, IOLTS 2004, Madeira Island, 12 July 2004 through 14 July 2004 ; 2004 , Pages 101-106 ; 0769521800 (ISBN); 9780769521800 (ISBN) ; Miremadi, S. G ; Sarbazi Azad, H ; Sharif University of Technology
2004
Abstract
Data integrity of words coming out of the caches needs to be checked to assure their correctness. This paper proposes a cache placement scheme, which provides high performance as well as high fault detection coverage. In this scheme, the cache space is divided into sets of different sizes. Here, the length of tag fields associated to each set is unique and is different from the other sets. The other remained bits of tags are used for protecting the tag using a fault detection scheme e.g., generalized parity. This leads to protect the cache without compromising performance and area with respect to the similar one, fully associative cache. The results obtained from simulating some standard...
Experimental evaluation of Master/Checker architecture using power supply- and software-based fault injection
, Article Proceedings - 10th IEEE International On-Line Testing Symposium, IOLTS 2004, Madeira Island, 12 July 2004 through 14 July 2004 ; 2004 , Pages 239-244 ; 0769521800 (ISBN); 9780769521800 (ISBN) ; Miremadi, S. G ; Mohandespour, M ; Sharif University of Technology
2004
Abstract
This paper presents an experimental evaluation of the effectiveness of the Master/Checker (M/C) architecture in a 32-bit Pentium® processor system using both power-supply disturbance (PSD) fault injection and software-implemented fault injection (SWIFI) methods. A total of 6000 faults were injected in the Master processor to measure the error detection coverage of the Checker processor. The results of the experiments with PSD fault injection show that the error detection coverage of the M/C architecture is about 66.13%, which is not quite effective. This low coverage depends on the high rate of Master processor hangs because of voltage fluctuation. The coverage increased to about 99.73% when...
A new variable structure control methodology for electrical/mechanical parameter estimation of induction motor
, Article 2003 American Control Conference, Denver, CO, 4 June 2003 through 6 June 2003 ; Volume 5 , 2003 , Pages 4047-4052 ; 07431619 (ISSN) ; Faezian, G ; Tabatabaei Y, H ; Sargolzaei, N ; Sharif University of Technology
2003
Abstract
Induction motor parameter estimation is generally needed for such purposes as fault detection and the achievement of high dynamic performance drives. This paper is an attempt to use variable structure control (VSC) methodology for the on-line estimation of several significant mechanical and electrical induction motor parameters. The estimated parameters are rotor resistance, magnetizing inductance, stator resistance and viscous damping coefficient In this combined control/estimation method, we propose to apply field-oriented control to the non-linear model of induction motor, and then transform the model by Input-state linearization into canonical form. Application of variable structure...
Performance evaluation of hybrid transfer switches in grounded and ungrounded medium-voltage electrical systems
, Article CIGRE/IEEE PES International Symposium Quality and Security of Electric Power Delivery Systems, CIGRE/PES 2003, 8 October 2003 through 10 October 2003 ; 2003 , Pages 91-96 ; 2858730156 (ISBN); 9782858730155 (ISBN) ; Mokhtari, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2003
Abstract
Application of a fast hybrid transfer switch (HTS) as a suitable tool for protection of sensitive electrical loads against power quality problems has attracted much attentions these days. In this paper, methods for desired control of a HTS which consists of a fast fault-detection method and a suitable firing and transfer strategy are proposed. Simulation results of a HTS under various operating conditions for two types of medium-voltage electrical systems, i.e. grounded (star connection) and ungrounded (delta connection) systems, with respect to total transfer time are presented. The results show the capability of the HTS and the proposed control methods in fast transferring of sensitive...
Switch level fault emulation
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 2778 , 2003 , Pages 849-858 ; 03029743 (ISSN); 3540408223 (ISBN); 9783540408222 (ISBN) ; Ejlali, A ; Sharif University of Technology
Springer Verlag
2003
Abstract
The switch level is an abstraction level between the gate level and the electrical level, offers many advantages. Switch level simulators can reliably model many important phenomena in CMOS circuits, such as bi-directional signal propagation, charge sharing and variations in driving strength. However, the fault simulation of switch level models is more time-consuming than gate level models. This paper presents a method for fast fault emulation of switch level circuits using FPGA chips. In this method, gates model switch level circuits and we can emulate mixed gate-switch level models. By the use of this method, FPGA chips can be used to accelerate the fault injection campaigns into switch...
Satellite Attitude Actuator Fault Detection and Identification Using Adaptive Neuro-Fuzzy Inference System (ANFIS)
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor)
Abstract
This thesis focuses on the detection and estimation of faults occurring in one of the reaction wheel axes of a three-axis stabilized satellite. The wheel axes are aligned with the satellite's body axes, and the emphasis is on the attitude (rather than position) of the satellite. The primary goal of the subsystem is to determine and control the satellite's attitude, transitioning from its initial state to a desired Earth-pointing state. It is assumed that environmental disturbances, including gravitational disturbances and Drag related disturbances, are considered. Based on this, a PID controller is designed after modeling the nonlinear kinematics and dynamics of the satellite using Euler...
Robust Reconstruction of Medical Ultrasound Images in The Presence of Transducer Faults
, Ph.D. Dissertation Sharif University of Technology ; Jahed, Mehran (Supervisor)
Abstract
Medical ultrasound imaging is one of the common imaging methods in modern medicine, which is used to diagnose and even treat some diseases due to its cheapness and harmlessness. Medical ultrasound transducer arrays have a significant error rate. They are a major cause of failure in ultrasound imaging systems. This problem causes a noticeable decrease in the quality of the images and medical misdiagnoses. The topics of accurate detection of the location and severity of the error or failure, as well as the compensation for weak transducers by signal processing methods, have received less attention from predecessor researchers. In this thesis, an innovative method for accurate error detection...
An Ensemble Approach for Fault Analysis in Internet of Things
, M.Sc. Thesis Sharif University of Technology ; Hessabi, Shahin (Supervisor)
Abstract
Today, data analysis has become a valuable tool in various fields in order to discover the forms or abnormal behavior of the system. For example, detecting credit card fraud, network intrusion, or detecting defects in sensors. In this thesis, a method for fault analysis is presented, which can be used as a monitoring tool to monitor the data that is received in a time series from an Internet of Things system and understand the behavior of the system. This method is designed in such a way that by matching the components with the input data, in general, it is applicable for our desired time series. The presented algorithm is implemented in an unsupervised environment using a statistical...
Speed Estimation for Fault Diagnosis in Machinery Using Vibration Signal
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor) ; Arghand, Hesamaddin (Co-Supervisor)
Abstract
Nowadays, condition monitoring and fault diagnosis are considered as one of the most important maintenance and diagnosis strategies in state-of-the-art industries. Serious damage such as machine and coupled equipment failure, machine failure in a neighborhood in case of severe damage, and production loss will be resulted in late fault detection. One of the critical information in condition monitoring is the machine's rotating speed. In many cases of condition monitoring, the rotating speed, and the machine's technical information (such as bearing characteristic frequency )is not available. In this study, a ruled-base model and an intelligent model are developed for machine running speed...
Develop a Monitoring Center Conceptual Framework for Chain Stores
, M.Sc. Thesis Sharif University of Technology ; Rajabi Ghahnaviyeh, Abbas (Supervisor)
Abstract
Among the equipment used in supermarkets, refrigeration systems should be the focus of energy efficiency initiatives; Because they are the biggest consumers of energy and refrigerant with significant maintenance costs. Fault detection and diagnosis (FDD) can provide considerable potential for energy savings as well as reduced maintenance costs. Although there have been numerous investigations of FDD for HVAC systems, there has been very little research on the application of FDD for supermarket refrigeration systems. Therefore, this thesis focuses on the application of FDD to these systems and helps to fill these research gaps. The studied system is a commercial refrigerator system on a...
Evaluating Effectiveness of Machine Learning Approaches in Oscillation Detection in Control Loops
, M.Sc. Thesis Sharif University of Technology ; Tavazoei, Mohammad Saleh (Supervisor)
Abstract
Oscillation in control loops is a common problem in industrial processes. To ensure proper system performance, oscillation in control loops must first be properly detected and then eliminated. Various non-machine learning methods have been used in oscillation detection for years, with the development of machine learning algorithms, hardware improvements and easy access to diverse data, these methods have also been used for oscillation detection in recent years. In the research conducted the field of oscillation detection with machine learning, the focus has been on the advantages of machine learning methods compared to other methods. In this thesis, the aim is to examine and compare...
Turn-to-Turn Fault Detection in Power Transformers in the Presence of Inrush Current
, M.Sc. Thesis Sharif University of Technology ; Hajipour, Ehsan (Supervisor)
Abstract
One of the most critical equipments in power grids are power transformers, which are vulnerable to damage due to the possibility of faults in its various components. A very common category of such faults is turn-to-turn fault in its winding. This fault initiates by the aging of the winding insulation with a short circuit of several adjacent loops to each other and if it is not detected quickly by the transformer protection, it will spread rapidly and can lead to irreparable failure in the transformer. Traditionally, turn-to-turn fault should be detected by mechanical pressure relays, however, due to the poor performance of these relays in the rapid detection of this type of fault, in the...
Geometric-Based Fault Diagnosis in a Grid-Connected Inverter
, Ph.D. Dissertation Sharif University of Technology ; Namvar, Mehrzad (Supervisor)
Abstract
Inverters are the main utility in transmitting power from distributed generation (DG) systems toward grid and their safe and immune performance has become a major concern among the system designers. In addition to poor power transmittance, faults in inverter can harm other equipment such as DG and local load. Consequently different protections has been considered to increase the reliability of these systems. Some of these protections like fuses and varistors are implemented in the hardware while others are considered in the processor. In the later class of protections, fault detection and isolation (FDI) system has been the subject of intense investigation in inverters over the past two...
Design and Implementation of a Fault Detecting Algorithm for a High Voltage Underground Cable Using UHF Wireless Measuring Method
, M.Sc. Thesis Sharif University of Technology ; Vakilian, Mehdi (Supervisor)
Abstract
One of the common problems in using high voltage network is the occurrence of partial electrical discharge in high voltage equipment such as cables. This problem may not be serious at first, but over time it can cause wear, corrosion, or reduction of equipment life, and eventually, if not prevented in a timely manner, can cause electrical sparks, larger problems, and possibly equipment and network become irreparable. On the one hand, due to very clear reasons, we need the voltage level to be high, and on the other hand, due to the application of high voltage level and the need to optimally design the insulation system to reduce their dimensions and construction costs, there will be the...
Application of SPM for Fault Detection and RUL Estimation; Comparison with Vibration Analysis
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor)
Abstract
Rolling element bearings (REBs) are one of the most critical components in rotating ma-chines. Failure of these components may lead to fatal and costly breakdowns in rotating machinery. Therefore, it is significant to detect faults at early stage accurately. The pur-pose of this study is to compare vibration analysis and shock pulse method (SPM) in early detection of fault and remaining useful life prediction of REBs. To the aim, a set of ac-celerated life tests on REBs was planned. Vibration and shock pulse values accelerated life tests of the REBs were simultaneously measured from the moment of start to the end of the failure by two vibration and shock pulse sensors and their changes were...
Fault Detection in Robotic Swarm
, M.Sc. Thesis Sharif University of Technology ; Alasti, Aria (Supervisor) ; Salarieh, Hassan (Co-Supervisor)
Abstract
Fault detection in swarm robots is one of the most important issues that has drawn a lot of scientists’ attention. Previous studies have shown a lot of problems regarding this issue, such as dependency of data-based methods to mission and high complexity of model-based methods on the condition that nonlinear models are used. Extended information filter is an applicable method for fault detection because it could turn the inverse of a big matrix to a simple summation of information that is so desired in terms of calculations. The goal of this study is to identify the agents with fault in swarm robots online by modifying the extended information filter. In this study, it has been attempted to...
Improvement of Inverter-based AC Microgrids Protection Against Short Circuit
, Ph.D. Dissertation Sharif University of Technology ; Mokhtari, Hossein (Supervisor) ; Blaabjerg, Frede (Co-Supervisor)
Abstract
Inverter-based distributed generations (IBDGs) have gained special interest in the electricity supply chain due to the advancements in power electronics technology. Power electronic inverters provide high-efficiency energy conversion with full controllability over a wide operating range, and ancillary services such as reactive power support and active filtering. Considering the voltage and frequency control capability of power inverters, supplying inverter-based micro-grid (IBMG) loads is now pissible. Despite the significant opportunities associated with such sources, they introduce new challenges that should be addressed properly. Reliable and accurate protection against short circuit...
An Accurate Algorithm for Power Transformer Turn to Turn Fault Detection to Enhance the Performance of Differential Relay
, Ph.D. Dissertation Sharif University of Technology ; Vakilian, Mehdi (Supervisor) ; Hajipour, Ehsan (Co-Supervisor)
Abstract
Power transformer is one of the most important equipment in the power system which plays a key role in the reliability and quality of power delivery. Among numerous failure modes of a typical power transformer, the turn-to-turn fault (TTF) is one of the most prominent reasons for its unplanned outage. A turn-to-turn fault quite often begins with the degradation of the winding insulation between two adjacent turns, then in a short time, this low-level fault can progress to a large number of turns and results in the transformer costly damages. Therefore, it is vital to detect TTF at an early stage and prevent its progression to a catastrophic disaster. The conventional percentage differential...
Fault Detection of Offshore Wind Turbines Using Data Driven Methods
, M.Sc. Thesis Sharif University of Technology ; Sadati, Nasser (Supervisor)
Abstract
Technology systems are vulnerable to various defects. Acuator failures reduce the performance of control systems and even they can damage the entire system. Incorrect reading from the sensors is the cause of many inefficiencies, because errors can reduce the quality and efficiency of a product line. In addition, failure of a single system's component can cause a system failure. Electromechanical energy conversion devices are composed of hundreds different components and subunits that are subject to varying adverse environmental conditions, and that is why the sensors, actuators, and components are likely to malfunction. Unexpected defects and unplanned repairs result in high operating costs...