• International Journal of Reliability and Applications
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• v.4 no.1
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• pp.1-12
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• 2003

Many software reliability growth models (SRGM's) based on a nonhomogeneous Poisson process (NHPP) have been proposed by many researchers. Most of the SRGM's which have been proposed up to the present treat the event of software fault-detection in the testing and operational phases as a counting process. However, if the size of the software system is large, the number of software faults detected during the testing phase becomes large, and the change of the number of faults which are detected and removed through debugging activities becomes sufficiently small compared with the initial fault content at the beginning of the testing phase. Therefore, in such a situation, we can model the software fault-detection process as a stochastic process with a continuous state space. In this paper, we propose a new software reliability growth model describing the fault-detection process by applying a mathematical technique of stochastic differential equations of an Ito type. We also compare our model with the existing SRGM's in terms of goodness-of-fit for actual data sets.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.6
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• pp.558-563
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• 2010

In this paper, the novel approach for the fault diagnosis of the bearing equipped with rotational mechanical facilities was studied. As research works, by applying the ball bearing used extensively in many industrial fields, experiments were conducted in order to propose the new prognostic method about the condition monitoring for the rotational bodies based on the condition analysis of infrared thermography. Also, by using the vibration spectrum analysis, the real time monitoring was performed. As results, it was confirmed that infrared thermography method could be adapted into monitor and diagnose the fault for bearing by evaluating quantitatively and qualitatively the temperature characteristics according to the condition of the ball bearing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.23-25
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• 1996

In this paper aims at studying the minimal test pattem of the RAM. This also propose a scheme of testing faults from the new fault model using the LLB. The length of test patterns are 6N(1-wsf), 9.5N(2-wsf), 7N(3-wsfl, 3N(4-wsf) operations in N-bit RAM. This test techniques can write into memory cell the number of write operations is reduced and then much testing time is saved. A test set which detects all positive-negative static t-ws faults for t=0, 1, 2, 3, 4 and detects all pattern sensitive fault in memory array. A new fault model, which encompasses the existing fault model Is proposed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.7
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• pp.994-1002
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• 2013

This study suggests a generalized availability and safety evaluation model to evaluate the influences to the system's fault tolerant capabilities depending on automatic fault detection function such as the automatic periodic testings. The conventional evaluation model of automatic fault detection function deals only with the self diagnostics, and supposes that the fault detection coverage of self diagnostics is always constant. But all of the fault detection methods could be degraded. For example, the periodic surveillance test has the potential human errors or test equipment errors, the self diagnostics has the potential degradation of built-in logics, and the automatic periodic testing has the potential degradation of automatic test facilities. The suggested evaluation models have incorporated the loss or erroneous behaviors of the automatic fault detection methods. The availability and the safety of each module of the safety grade platform have been evaluated as they were applied the automatic periodic test methodology and the fault tolerant evaluation models. The availability and safety of the safety grade platform were improved when applied the automatic periodic testing. Especially the fault tolerant capability of the processor module with a weak self-diagnostics and the process parameter input modules were dramatically improved compared to the conventional cases. In addition, as a result of the safety evaluation of the digital reactor protection system, the system safety of the digital parts was improved about 4 times compared to the conventional cases.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.4
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• pp.610-617
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• 1987

This thesis is concerned with fault-tolerance of a B-net (Beta-network) which is a kind of interconnection network in the multicomputer system. In this paper, a method for obtaining Maximal Tolerable Fault Set(MTFS) of link line connecting switching elements in the arbitrary B-net is presented. Using this method, it is seen that testing of DFA capability is possible when s-a-faults of link line occur, and criterion for determining degree of fault- tolerance of a B-net in terms of link line is introduced.

• Journal of Internet Computing and Services
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• v.14 no.1
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• pp.31-39
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• 2013

Generally, there can be a interface discrepancy between the legacy hardware and the new software in combining new software component with reused hardware components in the embedded system. This kind of the interface discrepancy may cause various types of faults and also result in declining interface fault tolerance. In this paper we propose a method to improve interface fault tolerance. First of all, the new interface discrepancy fault type which has not been dealt with before is to be defined and next the testing method for generating test paths is proposed by considering the new defined interface discrepancy fault type in this paper. Several tests show that the proposed method detects more fatal faults about 7.9% in comparison with the existing testing method for commercial broadcasting receiver. Since the proposed method can provide software developers with test paths to be available earlier on the software development cycle, in addition, software developers can regard on interface discrepancy fault in advance. Consequently, more efficient test planning can be established to improve the interface fault tolerance.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.6
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• pp.540-545
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• 2012

In this paper, we propose a fault diagnosis method using artificial neural network and SVM (Support Vector Machine) to detect and isolate faults in the nonlinear systems. The proposed algorithm consists of two main parts: fault detection through threshold testing using a artificial neural network and fault isolation by SVM fault classifier. In the proposed method a fault is detected when the errors between the actual system output and the artificial neural network nominal system output cross a predetermined threshold. Once a fault in the nonlinear system is detected the SVM fault classifier isolates the fault. The computer simulation results demonstrate the effectiveness of the proposed SVM and artificial neural network based fault diagnosis method.

• Journal of Korean Society for Quality Management
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• v.22 no.2
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• pp.33-40
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• 1994

Most software reliability models and other methods attempt to estimate some measures based on its fault history. There are several phases of the software life cycle including testing phase. We can propose it's stopping rule to decide when to stop the testing and pass it on to the next phase by considering the detailed structure of software and calculating the failure rate when each fault was detected. Downs (1985) proposed a method which was developed for estimating the failure rate applicable only to two-level profiles. In this paper, I extended to profiles involving more levels.

• Journal of Korean Society for Quality Management
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• v.34 no.3
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• pp.73-78
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• 2006

In this paper, we propose a software reliability growth model based on the testing domain in the software system, which is isolated by the executed test cases in software testing. In particular, our model assumes an imperfect debugging environment in which new faults are introduced in the fault-correction process, and is formulated as a nonhomogeneous Poisson process(NHPP). Further, it is applied to fault-detection data, the results of software reliability assessment are shown, and comparison of goodness-of-fit with the existing software reliability growth model is performed.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.229-240
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• 1995

This paper proposes a new weighted random pattern testing technique to detect path delay faults in combinational logic circuits. When computing the probability of signal transition at primitive logic elements of CUT(Circuit Under Test) by the primary input, the proposed technique uses the information on the structure of CUT for initialization vectors and vectors generated by pseudo random pattern generator for test vectors. We can sensitize many paths by allocating a weight value on signal lines considering the difference of the levels of logic elements. We show that the proposed technique outperforms existing testing method in terms of test length and fault coverage using ISCAS '85 benchmark circuits. We also show that the proposed testing technique generates more robust test vectors for the longest and near-longest paths.