• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.342-345
• /
• 2009

Electro galvanized steel is electroplated cold roller steel for improving corrosion resistance and paintability, and is widely used in automobiles and home appliances. In the electroplating line for manufacturing electro galvanized steel if plating process is carried out with impurity on conductor roll surface, the defects in manufacturing process occurs because of steel fault. For quality, polishing is always required to separate impurity on surface of conductor roll. In this study, finite element analysis of wear for polisher brush is carried out for replaced time of it.

• Journal of Digital Convergence
• /
• v.11 no.12
• /
• pp.431-438
• /
• 2013

In this paper we proposed a intelligent recommendation processor that the type of auto parts failures that may occur in the checkout process is represented by association relationship and the relationship was implemented with ontology. For this purpose, we defined 10 kinds of failure types and their associated parts, and we designed to simulate the recommendation process of five views. For components to be checked with the type of fault, it was possible to be expansion recommendation to the intelligent by controlling the weight value according to the relationship on the components.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.51 no.9
• /
• pp.389-401
• /
• 2002

To complement the conventional fusion methodologies of state fusion and measurement fusion, a time-propagated measurement fusion methodology is proposed. Various aspects of common process noise are investigated regarding information preservation. Based on time-propagated measurement fusion methodology, four compression filters are derived. The derived compression filters are efficient in asynchronous sensor fusion and fault detection since they maintain correct statistical information. A new batch Kalman recursion is proposed to show the optimality under the time-propagated measurement fusion methodology. A simple simulation result evaluates estimation efficiency and characteristic.

• Communications for Statistical Applications and Methods
• /
• v.12 no.3
• /
• pp.697-704
• /
• 2005

Computer software has gradually become an indispensable elements in many aspects of our daily lives and an important factor in numerous systems. In recent years, it is not unusual that the software cost is more than the hardware cost in many situations. In addition to the costs of developing software, the repair cost resulting from the software failures are even more significant. In this paper, a cost model with warranty cost, time to remove each fault detected in the software system, and delivery delay cost is developed. We use a software reliability model based on non-homogeneous Poisson process (NHPP). We discuss the optimal release policies to minimize the expected total software cost. Numerical examples are provided to illustrate the results.

• Journal of Information Processing Systems
• /
• v.6 no.2
• /
• pp.235-252
• /
• 2010

Regression testing is a very costly process performed primarily as a software maintenance activity. It is the process of retesting the modified parts of the software and ensuring that no new errors have been introduced into previously tested source code due to these modifications. A regression test selection technique selects an appropriate number of test cases from a test suite that might expose a fault in the modified program. In this paper, we propose both a regression test selection and prioritization technique. We implemented our regression test selection technique and demonstrated in two case studies that our technique is effective regarding selecting and prioritizing test cases. The results show that our technique may significantly reduce the number of test cases and thus the cost and resources for performing regression testing on modified software.

• Journal of the korean Society of Automotive Engineers
• /
• v.14 no.5
• /
• pp.83-94
• /
• 1992

There has been a suggestion of many techniques as the methods of diagnosis for rotational machinery. In this study, HFRT was used as the analysis method for ball bearing of automobile and was compared with the conventional ANC technique. And this paper presented the computer simulation process about fault types and noise for the validity of the algorithm and identification of the physical meanings of HFRT. Also, experiment was performed using ball bearing and the results showed that HFRT was much more effective than the conventional methods in diagnostic process.

• Proceedings of the KIEE Conference
• /
• 2006.10c
• /
• pp.588-590
• /
• 2006

Recently, many on-line approaches to instrument channel surveillance (drift monitoring and fault detection) have been reported worldwide. On-line monitoring (OLM) method evaluates instrument channel performance by assessing its consistency with other plant indications through parametric or non-parametric models. The heart of an OLM system is the model giving an estimate of the true process parameter value against individual measurements. This model gives process parameter estimate calculated as a function of other plant measurements which can be used to identify small sensor drifts that would require the sensor to be manually calibrated or replaced. This paper describes an improvement of auto-associative kernel regression by introducing a correlation coefficient weighting on kernel distances. The prediction performance of the developed method is compared with conventional auto-associative kernel regression.

• Journal of Integrative Natural Science
• /
• v.10 no.4
• /
• pp.249-257
• /
• 2017

The main focus when developing software is to improve the reliability and stability of a software system. We are enjoying a very comfortable life thanks to modern civilization, however, comfort is not guaranteed to us. Once software systems are introduced, the software systems used in the field environments are the same as or close to those used in the development-testing environment; however, the systems may be used in many different locations. Development of software system is a difficult and complex process. Generally, existing software reliability models are applied to software testing data and then used to make predictions on the software failures and reliability in the field. In this paper, we present an improved exponential NHPP software reliability model in different development environments, and examine the goodness-of-fit of improved exponential model and other model based on two datasets. The results show that the proposed model fits significantly better than other NHPP software reliability model.

• The Korean Journal of Applied Statistics
• /
• v.23 no.3
• /
• pp.573-584
• /
• 2010

This paper considers the differences in the software execution environments in the testing phase and the operational phase to determine the optimal release time and warranty period of software systems. We formulate equations for the total expected software cost until the end of the software life cycle based on the NHPP. In addition, we derive the optimal release time that minimizes the total expected software cost for an imperfect debugging software reliability model. Finally, we analyze the sensitivity of the optimal testing and maintenance design related to variation of the cost model parameters based on the fault data observed in the actual testing process, and discuss the quantitative properties of the proposed model.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.25 no.1
• /
• pp.49-55
• /
• 2002

For making a lead terminal(condenser, resistor etc.), it is the matter that lead wire have to be supplied smooth without twisting and curving when it is supplied to the further processing (cutting, forming, attach process) after it being forwarded. The purpose of this study is to solve the winding claims of lead wire through the structural expansion of winding equipment to which the improvement of packing equipment to forward safely and supply the lead wire and QFD method are applied. The results of this study is available to solve the technical problem caused by the installation of the existing flyer system for the prevention of twisting and can expect the quality assurance as it prevents the claim(surface fault) caused by the bumping among lead wire which are involved in the packing equipment in its moving stage.