scholarly journals Construction and application of march tests for pattern sensitive memory faults detection

Informatics ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 25-42
Author(s):  
V. N. Yarmolik ◽  
V. A. Levantsevich ◽  
D. V. Demenkovets ◽  
I. Mrozek
Keyword(s):  
Fault Detection ◽  
Multiple Testing ◽  
High Efficiency ◽  
Fault Coverage ◽  
Memory Cells ◽  
March Test ◽  
Storage Devices ◽  
Coupon Collector ◽  
March Tests ◽  
Analytical Expressions

The urgency of the problem of testing storage devices of modern computer systems is shown. The mathematical models of their faults and the methods used for testing the most complex cases by classical march tests are investigated. Passive pattern sensitive faults (PNPSFk) are allocated, in which arbitrary k from N memory cells participate, where k << N, and N is the memory capacity in bits. For these faults, analytical expressions are given for the minimum and maximum fault coverage that is achievable within the march tests. The concept of a primitive is defined, which describes in terms of march test elements the conditions for activation and fault detection of PNPSFk of storage devices. Examples of march tests with maximum fault coverage, as well as march tests with a minimum time complexity equal to 18N are given. The efficiency of a single application of tests such as MATS ++, March C− and March PS is investigated for different number of k ≤ 9 memory cells involved in PNPSFk fault. The applicability of multiple testing with variable address sequences is substantiated, when the use of random sequences of addresses is proposed. Analytical expressions are given for the fault coverage of complex PNPSFk faults depending on the multiplicity of the test. In addition, the estimates of the mean value of the multiplicity of the MATS++, March C− and March PS tests, obtained on the basis of a mathematical model describing the problem of the coupon collector, and ensuring the detection of all k2k PNPSFk faults are given. The validity of analytical estimates is experimentally shown and the high efficiency of PNPSFk fault detection is confirmed by tests of the March PS type.

scholarly journals Pseudoexhaustive memory testing based on March A type march tests

Informatics ◽  
2020 ◽  
Vol 17 (2) ◽  
pp. 54-70
Author(s):  
V. N. Yarmolik ◽  
I. Mrozek ◽  
S. V. Yarmolik
Keyword(s):  
High Efficiency ◽  
Combinatorial Problem ◽  
Necessary Condition ◽  
Memory Testing ◽  
Memory Cells ◽  
Test Procedures ◽  
Memory Faults ◽  
Coupon Collector ◽  
March Tests ◽  
The Mathematical Model

The relevance of testing of memory devices of modern computing systems is shown. The methods and algorithms for implementing test procedures based on classical March tests are analyzed. Multiple March tests are highlighted to detect complex pattern-sensitive memory faults. To detect them, the necessary condition that test procedures must satisfy to deal complex faults, is substantiated. This condition is in the formation of a pseudo-exhaustive test for a given number of arbitrary memory cells. We study the effectiveness of single and double application of tests like MATS ++, March C– and March A, and also give its analytical estimates for a different number of k ≤ 10 memory cells participating in a malfunction. The applicability of the mathematical model of the combinatorial problem of the coupon collector for describing multiple memory testing is substantiated. The values of the average, minimum, and maximum multiplicity of multiple tests are presented to provide an exhaustive set of binary combinations for a given number of arbitrary memory cells. The validity of analytical estimates is experimentally shown and the high efficiency of the formation of a pseudo-exhaustive coverage by tests of the March A type is confirmed.

Two-Run RAM March Testing with Address Decimation

2016 ◽  
Vol 26 (02) ◽  
pp. 1750031 ◽  
Author(s):  
Ireneusz Mrozek ◽  
Vyacheslav Yarmolik
Keyword(s):  
Selection Process ◽  
Random Access ◽  
Test Session ◽  
Analytical Investigation ◽  
Fault Coverage ◽  
Test Procedures ◽  
March Test ◽  
Sequence Selection ◽  
Time Standard ◽  
March Tests

Conventional march memory tests have high fault coverage, especially for simple faults like stack-at fault (SAF), transition fault (TF) or coupling fault (CF). The same-time standard march tests, which are based on only one run, are becoming insufficient for complex faults like pattern-sensitive faults (PSFs). To increase fault coverage, the multi-run transparent march test algorithms have been used. This solution is especially suitable for built-in self-test (BIST) implementation. The transparent BIST approach presents the incomparable advantage of preserving the content of the random access memory (RAM) after testing. We do not need to save the memory content before the test session or to restore it at the end of the session. Therefore, these techniques are widely used in critical applications (medical electronics, railway control, avionics, telecommunications, etc.) for periodic testing in the field. Unfortunately, in many cases, there is very limited time for such test sessions. Taking into account the above limitations, we focus on short, two-run march test procedures based on counter address sequences. The advantage of this paper is that it defines requirements that must be taken into account in the address sequence selection process and presents a deeply analytical investigation of the optimal address decimation parameter. From the experiments we can conclude that the fault coverage of the test sessions generated according to the described method is higher than in the case of pseudorandom address sequences. Moreover, the benefit of this solution seems to be low hardware overhead in implementation of an address generator.

scholarly journals Analysis of multibackground memory testing techniques

2010 ◽  
Vol 20 (1) ◽  
pp. 191-205 ◽  
Author(s):  
Ireneusz Mrozek
Keyword(s):  
Initial Conditions ◽  
Fault Coverage ◽  
Fault Model ◽  
Memory Testing ◽  
March Test ◽  
Transition Faults ◽  
Complex Fault ◽  
Pattern Sensitive Faults ◽  
Testing Techniques ◽  
March Tests

Analysis of multibackground memory testing techniquesMarch tests are widely used in the process of RAM testing. This family of tests is very efficient in the case of simple faults such as stuck-at or transition faults. In the case of a complex fault model—such as pattern sensitive faults—their efficiency is not sufficient. Therefore we have to use other techniques to increase fault coverage for complex faults. Multibackground memory testing is one of such techniques. In this case a selected March test is run many times. Each time it is run with new initial conditions. One of the conditions which we can change is the initial memory background. In this paper we compare the efficiency of multibackground tests based on four different algorithms of background generation.

scholarly journals Transparent memory tests with even repeating addresses for storage devices

Informatics ◽  
2021 ◽  
Vol 18 (3) ◽  
pp. 18-35
Author(s):  
V. N. Yarmolik ◽  
I. M. Mrozek ◽  
V. A. Levantsevich ◽  
D. V. Demenkovets
Keyword(s):  
High Efficiency ◽  
Basic Element ◽  
Distance Metrics ◽  
Optimal Test ◽  
Computing Systems ◽  
Storage Devices ◽  
Pattern Sensitive Faults ◽  
The Difference ◽  
March Tests ◽  
Reference Signature

The urgency of the problem of memory testing of modern computing systems is shown. Mathematical models describing the faulty states of storage devices and the methods used for their detection are investigated. The concept of address sequences (pA) with an even repetition of addresses is introduced, which are the basis of the basic element included in the structure of the new transparent march tests March _pA_1 and March _pA_2. Algorithms for the formation of such sequences and examples of their implementations are given. The maximum diagnostic ability of new tests is shown for the case of the simplest faults, such as constant (SAF) and transition faults (TF), as well as for complex pattern sensitive faults (PNPSFk). There is a significantly lower time complexity of the March_pA_1 and March_pA_2 tests compared to classical transparent tests, which is achieved at the expense of less time spent on obtaining a reference signature. New distance metrics are introduced to quantitatively compare the effectiveness of the applied pA address sequences in a single implementation of the March_pA_1 and March_pA_2 tests. The basis of new metrics is the distance D(A(j), pA) determined by the difference between the indices of repeated addresses A(j) in the sequence pA. The properties of new characteristics of the pA sequences are investigated and their applicability is evaluated for choosing the optimal test pA sequences that ensure the high efficiency of new transparent tests. Examples of calculating distance metrics are given and the dependence of the effectiveness of new tests on the numerical values of the distance metrics is shown. As well as in the case of classical transparent tests, multiple applications of new March_pA_1 and March_pA_2 tests are considered. The characteristic V(pA) is introduced, which is numerically equal to the number of different values of the distance D(A(j), pA) of addresses A(j) of the sequence pA. The validity of analytical estimates is experimentally shown and high efficiency of fault detection by the tests March_pA_1 and March_pA_2 is confirmed by the example of coupling faults for p = 2.

scholarly journals Instantaneous Electromagnetic Torque Components in Synchronous Motors Fed by Load-Commutated Inverters

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3223
Author(s):  
Gabriel Ekemb ◽  
Fouad Slaoui-Hasnaoui ◽  
Joseph Song-Manguelle ◽  
P. M. Lingom ◽  
Issouf Fofana
Keyword(s):  
High Efficiency ◽  
Air Gap ◽  
International Standards ◽  
Synchronous Motors ◽  
Gas Compression ◽  
Variable Frequency Drives ◽  
Torsional Analysis ◽  
Analytical Expressions ◽  
Very High ◽  
Excitation Circuit

This paper proposes time-domain analytical expressions of the instantaneous pulsating torque components in a synchronous machine air gap when supplied by a load-commutated-inverter (LCI) system. The LCI technology is one of the most used variable frequency drives when very high power and low speed are required in applications such as pipeline recompression and decompression, as well as liquefied natural gas compression. In such applications, synchronous motors are used because of their high efficiency resulting from a separated supply of the current to their rotor through the excitation circuit. These applications usually have long and flexible shafts, which are very sensitive to torsional vibration excitation when their natural frequencies interact with any external torque applied to the shaft. A torsional analysis is required by international standards to assess the survivability of the shaft through the overall speed range of the motor. Therefore, the magnitude and frequencies of the motor air-gap torque are needed for such evaluation. The proposed developments are supported by numerical simulations of LCI systems in a large range of operation range. From the simulation results, torque harmonic families are derived and expressed in a parametric form, which confirm the accuracy of the proposed relationships.

RNN-based Fault Detection Method for MMC Photovoltaic Grid-connected System

2021 ◽  
Vol 14 ◽  
Author(s):  
Yuqi Pang ◽  
Gang Ma ◽  
Xiaotian Xu ◽  
Xunyu Liu ◽  
Xinyuan Zhang
Keyword(s):  
Fault Detection ◽  
Detection Method ◽  
Circuit Breaker ◽  
Detection Methods ◽  
Multilevel Converters ◽  
Modular Multilevel Converters ◽  
Dc Circuit Breaker ◽  
Linear Elements ◽  
Hidden Layer ◽  
Analytical Expressions

Background: Fast and reliable fault detection methods are the main technical challenges faced by photovoltaic grid-connected systems through modular multilevel converters (MMC) during the development. Objective: Existing fault detection methods have many problems, such as the inability of non-linear elements to form accurate analytical expressions, the difficulty of setting protection thresholds and the long detection time. Method: Aiming at the problems above, this paper proposes a rapid fault detection method for photovoltaic grid-connected systems based on Recurrent Neural Network (RNN). Results: The phase-to-mode transformation is used to extract the fault feature quantity to get the RNN input data. The hidden layer unit of the RNN is trained through a large amount of simulation data, and the opening instruction is given to the DC circuit breaker. Conclusion: The simulation verification results show that the proposed fault detection method has the advantage of faster detection speed without difficulties in setting and complicated calculation.

Signature-Encryption Scheme: A Novel Solution to Mobile Computation

2012 ◽  
Vol 546-547 ◽  
pp. 1415-1420
Author(s):  
Hai Yong Bao ◽  
Man De Xie ◽  
Zhen Fu Cao ◽  
Shan Shan Hong
Keyword(s):  
Mobile Communication ◽  
High Efficiency ◽  
Discrete Logarithm ◽  
Communication Technologies ◽  
Random Oracle ◽  
Security Requirements ◽  
Encryption Scheme ◽  
Daily Lives ◽  
Storage Devices ◽  
Diffie Hellman

Mobile communication technologies have been widely utilized in daily lives, many low-computing-power and weakly-structured-storage devices have emerged, such as PDA, cell phones and smart cards, etc. How to solve the security problems in such devices has become a key problem in secure mobile communication. In this paper, we would like to propose an efficient signature-encryption scheme. The security of the signature part is not loosely related to Discrete Logarithm Problem (DLP) assumption as most of the traditional schemes but tightly related to the Decisional Diffie-Hellman Problem (DDHP) assumption in the Random Oracle Models. Different from the existing solutions, our scheme introduces a trusted agent of the receiver who can filter the “rubbish” messages beforehand. Thus, with high efficiency in computation and storage, it is particularly suitable for the above mobile devices with severely constrained resources and can satisfy the security requirements of mobile computations.

Bearing fault detection under time-varying speed based on empirical wavelet transform, cultural clan-based optimization algorithm, and random forest classifier

2021 ◽  
pp. 107754632110470
Author(s):  
Moussaoui Imane ◽  
Chemseddine Rahmoune ◽  
Mohamed Zair ◽  
Djamel Benazzouz
Keyword(s):  
Wavelet Transform ◽  
Random Forest ◽  
Fault Detection ◽  
Optimization Algorithm ◽  
High Efficiency ◽  
Time Varying ◽  
Bearing Fault ◽  
Bearing Fault Detection ◽  
Empirical Wavelet Transform ◽  
Bearing Condition Monitoring

Bearings are massively utilized in industries of nowadays due to their huge importance. Nevertheless, their defects can heavily affect the machines performance. Therefore, many researchers are working on bearing fault detection and classification; however, most of the works are carried out under constant speed conditions, while bearings usually operate under varying speed conditions making the task more challenging. In this paper, we propose a new method for bearing condition monitoring under time-varying speed that is able to detect the fault efficiently from the vibration signatures. First, the vibration signal is processed with the Empirical Wavelet Transform to extract the AM-FM modes. Next, time domain features are calculated from each mode. Then, the features’ set is reduced using the Cultural Clan-based optimization algorithm by removing the redundant and unimportant parameters that may mislead the classification. Finally, an ensemble learning algorithm “Random Forest” is used to train a model able to classify the fault based on the selected features. The proposed method was tested on a time-varying real dataset consisting of three different bearing health states: healthy, outer race defect, and inner race defect. The obtained results indicate the ability of our proposed method to handle the speed variability issue in bearing fault detection with high efficiency.

scholarly journals Fault Detection and Exclusion for Tightly Coupled GNSS/INS System Considering Fault in State Prediction

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 590 ◽  
Author(s):  
Shizhuang Wang ◽  
Xingqun Zhan ◽  
Yawei Zhai ◽  
Baoyu Liu
Keyword(s):  
Fault Detection ◽  
Navigation System ◽  
High Efficiency ◽  
Hypothesis Test ◽  
Global Navigation Satellite Systems ◽  
Measurement Unit ◽  
Decision Strategy ◽  
Integration Model ◽  
State Prediction ◽  
Tightly Coupled

To ensure navigation integrity for safety-critical applications, this paper proposes an efficient Fault Detection and Exclusion (FDE) scheme for tightly coupled navigation system of Global Navigation Satellite Systems (GNSS) and Inertial Navigation System (INS). Special emphasis is placed on the potential faults in the Kalman Filter state prediction step (defined as “filter fault”), which could be caused by the undetected faults occurring previously or the Inertial Measurement Unit (IMU) failures. The integration model is derived first to capture the features and impacts of GNSS faults and filter fault. To accommodate various fault conditions, two independent detectors, which are respectively designated for GNSS fault and filter fault, are rigorously established based on hypothesis-test methods. Following a detection event, the newly-designed exclusion function enables (a) identifying and removing the faulty measurements and (b) eliminating the effect of filter fault through filter recovery. Moreover, we also attempt to avoid wrong exclusion events by analyzing the underlying causes and optimizing the decision strategy for GNSS fault exclusion accordingly. The FDE scheme is validated through multiple simulations, where high efficiency and effectiveness have been achieved in various fault scenarios.

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