• Electrical & Electronic Materials
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• v.10 no.4
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• pp.349-354
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• 1997

This paper aims at studying the improvement of test method for t-weight sensitive fault (t-wsf) detect. The development of RAM fabrication technology results in not only the increase at device density on chips but also the decrease in line widths in VLSI. But, the chip size that was large and complex is shortened and simplified while the cost of chips remains at the present level, in many cases, even lowering. First of all, The testing patterns for RAM fault detect, which is apt to be complicated , need to be simplified. This new testing method made use of Local Lower Bound (L.L.B) which has the memory with the beginning pattern of 0(l) and the finishing pattern of 0(1). The proposed testing patterns can detect all of RAM faults which contain stuck-at faults, coupling faults. The number of operation is 6N at 1-weight sensitive fault, 9,5N at 2-weight sensitive fault, 7N at 3-weight sensitive fault, and 3N at 4-weight sensitive fault. This test techniques can reduce the number of test pattern in memory cells, saving much more time in test, This testing patterns can detect all static weight sensitive faults and pattern sensitive faults in RAM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1537-1545
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• 1993

In this paper, we design a pattern generator and a fault position detector to implement the proposed fault test algorithms which are Column Weight Sensitive Fault (CWSF) test algorithm and bit line decoder fault test algorithm for performing the Built-In Self Test(BIST) in RAM. A pattern generator consists of an address generator and a data generator. An address generator is divided into a row address generator for effective address and a column address generator for sequential and parallel addresses. A fault position detector is designed to determine whether full occurred or not and to find the position of the fault. We verify the implemented circuits by the simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.7
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• pp.47-53
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• 2015

As the industrial development in Korea, the power demand is rapidly increased. The power system has been extended and complicated to meet the power demand. However, the fault current increases because the structure of power system reduces the equivalent impedance. One of the solutions to reduce the fault current is Superconducting Fault Current Limiter(SFCL) and the researches of SFCL application have much conducted. In this paper, we used the Circuit Breker Burden Index(CBBI) to select application location of SFCL because the CBBI may consider a fault current of each line. In addition, this paper divided the weight factor used to calculate the CBBI on a case by case basis and analyzed this characteristics through experiment.

• Journal of Power Electronics
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• v.19 no.2
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• pp.443-453
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• 2019

As the core component of transmission systems, converters are very prone to failure. To improve the accuracy of fault diagnosis for wind power converters, a fault feature extraction method combined with a wavelet transform and compressed sensing theory is proposed. In addition, an improved AdaBoost-SVM is used to diagnose wind power converters. The three-phase output current signal is selected as the research object and is processed by the wavelet transform to reduce the signal noise. The wavelet approximation coefficients are dimensionality reduced to obtain measurement signals based on the theory of compressive sensing. A sparse vector is obtained by the orthogonal matching pursuit algorithm, and then the fault feature vector is extracted. The fault feature vectors are input to the improved AdaBoost-SVM classifier to realize fault diagnosis. Simulation results show that this method can effectively realize the fault diagnosis of the power transistors in converters and improve the precision of fault diagnosis.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.4
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• pp.22-30
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• 1992

A redundant control scheme which can maintain its tracking capability in the case of a controller failure is proposed for the industrial applications which need high reliability with fault-tolerance. It consists of two identical controllers and a switching mechanism which includes failure detection and reconfiguration algorithm. The new detection method against controller failure using fuzzy logic enables the detection of controller failures without failure assumptions through the instability of the failed controller. The failed controller is smoothly removed from the control loop by reducing time weight of the failed controller.

• Economic and Environmental Geology
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• v.53 no.1
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• pp.71-85
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• 2020

To understand behavior of fault cores in the field of geotechnical and geological engineering, we present an investigation of the physical properties (breccia and clay contents, unit weight, porosity, and water content) and friction characteristics (internal friction angle and cohesion) of fault cores, in granitic, sedimentary, and volcanic rocks in South Korea. The breccia contents in the fault cores are positively correlated with unit weight and negatively correlated with clay content, porosity, and water content. The inter-quartile ranges of internal friction angles and cohesion calculated from direct shear tests are 16.7-38.1° and 2.5-25.3 kPa, respectively. The influence of physical properties on the friction characteristics of the fault cores was analyzed and showed that in all three rock types the internal friction angles are positively correlated with breccia content and unit weight, and negatively correlated with clay content, porosity, and water content. In contrast, the cohesions of the fault cores are negatively correlated with breccia content and unit weight, and positively correlated with clay content, porosity, and water content.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.714-717
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• 1996

This paper presents a fault detection and diagnosis methodologies based on weighted symptom model and pattern matching between the coming fault propagation trend and the simulated one. At the first step, backward chaining is used to find the possible cause candidates for the faults. The weighted symptom model(WSM) is used to generate those candidates. The weight is determined from dynamic simulation. Using WSMs, the methodology can generate the cause candidates and rank them according to the probability. Secondly, the fault propagation trends identified from the partial or complete sequence of measurements are compared to the standard fault propagation trends stored a priori. A pattern matching algorithm based on a number of triangular episodes is used to effectively match those trends. The standard trends have been generated using dynamic simulation and stored a priori. The proposed methodology has been illustrated using two case studies and showed satisfactory diagnostic resolution.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.10
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• pp.1259-1263
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• 1999

In this paper, a method to guarantee system continuity is developed, which can be applied to discontinuity problem in the time domain of restructurable control system. This method can be summarized as input alternation using weight change considering convergence speed of system mode. Input is changed from 'system continuity guarantee input,' which is defined as a input that minimizes the change of state variables, to 'alternative controller input,' which is selected by Neil's PI/EAM[3]. AIDC aircraft model is used for simulation. By showing the waveform of system input and state variable, we can sure that this method is effective for depression of system shock like jerk.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.6
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• pp.72-84
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• 2000

The test patterns for path delay faults consist of two patterns. So in order to test the delay faults, a new weight generation algorithm that is different from the weight generation algorithm for stuck-at faults must be applied. When deterministic test patterns for weight calculation are used, the deterministic test patterns must be divided into several subsets, so that Hamming distances between patterns are not too long. But this method makes the number of weight sets too large in delay testing, and may generate inaccurate weights. In this pater, we perform fault simulation without pattern partition. Experimental results for ISCAS 89 benchmark circuits prove the effectiveness of the new weight generation algorithm proposed in this paper.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.173-178
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• 2008

Electro-hydraulic brake system has many advantages. It provides improved braking performance and stability functions. It also removes complex mechanical parts for freedom of design, improves maintenance requirements and reduces unit weight. However, the EHB system should be dependable and have back-up redundancy in case of a failure. In this paper, the model-based fault diagnosis system is developed to monitor the brake status using the analytical redundancy method. The performance of the model-based fault diagnosis system is verified in real-time simulation. It demonstrates the effectiveness of the proposed system in various faulty cases.