• Journal of Applied Reliability
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• v.16 no.1
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• pp.71-77
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• 2016

Purpose: Root cause analysis (RCA) refers to any systematic process that identifies the causes that contribute to a focus event. The immediate cause of a focus event is often a symptom of underlying causes and may not truly identify the root causes that should be identified and addressed. Currently many RCA tools are available. Different investigators use different RCA tools on different issues. No standardized or commonly agreed way to analyse root causes exists. The purpose of this study is to propose the methodology of RCA process commonly useable for various issues. Methods: The methodology of RCA process is produced based on the hybrid RCA tools. The effectiveness assessment matrix of actions through the root cause candidates is presented. Results: No single RCA technique proposed has so far covered all necessary aspects. A hybrid approach which combines the best features of various techniques is proposed. The effectiveness assessment matrix helps us to identify the root cause to correct or eliminate system vulnerabilities effectively. Conclusion: This hybrid approach and effectiveness assessment matrix can provide guidance of RCA process across many industries and situations.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.287-292
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• 2005

Safety of Station electric equipment is not analysed yet. this paper try the safety first times on the basis of hazards which railway stations contain. The stations use many electric equipment such as lights, escalator and elevator for facilitating for passengers and public moving, HVAC system making good environment and so on. The electric equipments could be changed to harmful systems to passengers and publics resulting from abnormal operation condition. To ensure safeties in the station, we need to identify and analyse the hazards in the station and to provide risk mitigation methods. In this paper, we shows processes and methods to ensure the safety, how to identify and analyse the hazards. Finally, we demonstrate how to mitigate the potential risks in the stations.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.335-339
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• 1998

This paper presents a closed loop identification algorithm in time domain. This algorithm can be used for identification of unstable system and for model validation of system which is difficult to derive analytical model. In time domain, projection filter, which projects a finite number of input output data of a system into its current space, is used to relate the state space model with a finite difference model. Then recursive relations between the Markov parameters and the ARX model coefficients are derived to identify the system, controller and Kalman filter Markov parameters recursively, which are finally used to identify the system, controller and Kalman filter gains. The NASA LAMSTF is used to validate the algorithms developed.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.1100-1102
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• 2000

Most systems in tile real world are non-linear and can be represented by the non-linear autoregressive moving average (NARMA) model. The extension of fuzzy system for modeling the system that is represented by NARMA model will be proposed in this paper. Here, fuzzy basis function (FBF) is used as fuzzy NARMA(p,q) model. Then, an approach to Identify fuzzy NARMA models based on fuzzy basis functions is proposed. The efficacy of the proposed approach is shown from experimental results.

• Proceedings of the Korea Association of Information Systems Conference
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• 1998.10a
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• pp.165-177
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• 1998

The purpose of this study, based on domestic sample businesses using EDI systems, is to identify success factors, which affect adoption of EDI systems by domestic business entities. And this paper also intends to provide guideline important in the establishment and management of EDI systems based factors identified. The major contents of this research are as follow. This paper, first, tries to develop conceptual framework based on previous research to identify factors which affect successful adoption of EDI systems. Second, it intends to develop new version of survey questionnaire by referring to various survey questionnaires previously used by similar studies. Third, it also intends to the extent of each factor on the successful adoption and implementation of EDI systems, and examines proposed hypotheses.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.1
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• pp.84-90
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• 2012

Various methods have been proposed to identify the flux position in an interior permanent magnet synchronous motor (IPMSM) without the use of mechanical sensors. To achieve this, a method that uses both the back electromotive force (EMF) and the saliency to identify the flux position in the IPMSM without the injection of high-frequency components at low speeds has been reported. This method was then extended in order to drive the motor with no load to a light load. We propose a combination of these methods with different proportional-integral (PI) controllers for controlling $di_{dest}$/dt and $di_{qest}$/dt. We also introduce compensation values $F_L$ and $F_H$ to reduce the position error when the estimation rule is being selected.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.83.1-83.1
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• 2012

The galaxy cluster is a good laboratory to test the cosmological model as well as the evolution of galaxies in the dense region. However the lack of wide and deep near-IR datasets has prevented to identify galaxy clusters at z>1. Here we merge a wide, deep near-IR datasets of UKIDSS DXS (J and K bands) and IMS (J band) with the CFHT Legacy Survey (CFHTLS) ugriz catalogue to detect galaxy clusters. We identify candidate galaxy clusters at z>0.8, where the near-IR dataset plays an important role to detect galaxies efficiently. The cluster mass is also estimated based on the cluster richness and the semi-analytical cosmological simulation.

• Structural Engineering and Mechanics
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• v.8 no.3
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• pp.285-297
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• 1999

A method is presented to find the location and magnitude of damage in a structure using data from dynamic tests. The test data include a combination of natural frequency measurements, taken before and after the occurrence of damage, and response measurements taken after damage. An algorithm is developed to identify localized increases in the flexibility of the structural members. Increases in flexibility are attributed to damage. The algorithm uses the sensitivity of the flexibility matrix to changes in the natural frequencies of the structure to identify the damage. A set of under determined equations is solved using an objective function which is derived from measurements of the system moments. Damage ranging from 10 to 60% increase in the flexibility of a member was successfully identified in a 50 d.o.f. structure, using a small number of natural frequency and velocity measurements.

• The Mathematical Education
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• v.42 no.3
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• pp.403-417
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• 2003

The purpose of this study is to analyze the effects of the use of calculators in elementary school mathematics education. For this purpose, we established the subject matters of the research as folloows; (1) to develop the lesson plan and the students' activity sheet related to the use of calculators. (2) to analyze the effects of the use of calculators when we applied the materials developed. Four classes of sixth grade students were sampled two elementary schools in D city. Two of them were assigned to the calculator group and the others to traditional group. The experiment was conducted for 10 class times. Two kinds of test instruments were used: pretest and post test. The pretest scores guaranteed that both groups were homogeneous. Post-test was used to identify the effect of use of calculator and the post-test scores were analyzed by t-test. We also used questionnaire to identify the students' change of attitude toward mathematics. The results of this study as fellows: (1) The calculator group got scores significantly higher than the traditional group on the test. (2) The students' attitude in calculator group was changed a little positively.

• Journal of Families and Better Life
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• v.16 no.1
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• pp.27-38
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• 1998

The purpose of this study was to identify the level of residential privacy perceived by the elderly and also to identify contributing factors on their perception of privacy. This study examined the relations among socio-demographic characteristics housing characteristics and personal perception of privacy. The number of 469 elderly aged 55 and over were interviewed in Seoul. Daejeon Jeonju and Daegu, The data were analyzed by statistical methods such as frequencies means and multiple liner regression analysis. The result showed that the significant variables related to the perception of residential privacy of the elderly were the personal self-esteem age housing tenure pattern of using spaces family solidarity and availability of the perception of private space. The perception of the privacy of the elderly can be affected by personal characteristics and the privacy can be achieved by improving their present housing environment.