• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.659-662
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• 2009

본 연구에서는 소프트웨어 제품을 개발하여 테스팅을 거친 후 사용자에게 인도하는 시기를 결정하는 방출문제에 대하여 연구되었다. 소프트웨어의 결함을 제거하거나 수정 작업 중에도 새로운 결함이 발생될 가능성이 있는 무한고장수를 가진 비동질적인 포아송 과정에 기초하고 수명분포는 신뢰도 측면에서 여러 분포들을 적합시키는데 효율적인 특성을 가진 와이블분포를 이용한 최적 방출시기에 관한 문제를 제시하여 소프트웨어 요구 신뢰도를 만족시키고 소프트웨어 개발 및 유지 총비용을 최소화 시키는 최적 소프트웨어 방출 정책에 대하여 논의되었다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.9 no.1
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• pp.9-16
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• 2005

The random signals defined as sums of the single frequency sinusoidal signals with random amplitudes and random phases or equivalently sums of functions obtained by adding a Sine and a Cosine function with random amplitudes, are used in the double randomization method for the Monte Carlo solution of the turbulent systems. We show that these random signals can be used for studying the properties of the Johnson noise by proving that constant multiples of these signals with uniformly distributed frequencies in a fixed frequency band satisfy the properties of the Gaussian white noise.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.211-218
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• 1998

In start-up process control applications it may be necessary to limit the sample size to one measurement. A control chart for individual measurements is used whenever it is desirable to examine each individual value from the process immediately. A possible option would be to use an exponential weighted moving(EWM), using modifying statistics with individual measurement, chart for monitoring the process center, and using a moving range (MR) chart for monitoring process variability. In this paper it is shown that there is scheme in using the EWM procedure based on average run length. An expression for the ARL is given in terms of an integral equation, approximated using numerical quadrature. In this case, where it is reasonable to assume normality and negligible autocorrelation in the observations, provide graphs that simplify the design of EWM-MR chart and taking method of exponential smoothing constant(λ) and constant(K) are suggested. The charts suggested above evaluate using the conditional probability.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.1
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• pp.9-17
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• 2006

This paper considers a six sigma project for improving productivity of the brace complement center pillar. The project follows a disciplined process of fife phases: define, measure, analyze, improve, and control. A process map is used to identify process input and output variables. Eleven key process input variables are selected by using X&Y matrix and FMEA, and finally eight vital few input variables are selected from analyze phase. The optimum process conditions of the vital few input variables are jointly obtained by maximizing productivity of the brace complement center pillar using DOE and alternative selection method.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.23-29
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• 2010

There are two kind of method to perform a safety management in industrial field. One is a management by safety manager employed in company and another one is safety management by acting agency. In case of the company that managed by the acting agency dose not coincide with the state of company and safety management performance because of the safety management is carry out by periodically. Therefore it is considered that the sufficient safety management is difficult. And a company that employ a safety manager also show a low level of safety management compare with the advanced country in view of safety and health. From the statistics of accident rate of the company, it is necessary that an improved safety management through the studying and analysing a coverall matters for the company that managed by acting company.

• Journal of Korean Institute of Industrial Engineers
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• v.13 no.2
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• pp.105-115
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• 1987

Although there are many theoretical methods for the transformation of random variables. it is difficult to find probability density functions for the new random variables because of the complexity in mathematics. The author developed a simulation model solving the above difficulties using FBI (Fortran Based Interpreter) routines. The FBI is a kind of language Interpreter analyzing the arithmetic statement in character data forms. In this paper. the FBI routines will be explained and the structure and applications of simulation model will be also demonstrated. Polynomial curve fitting method is applied to define the probability density function which can not be defined by well-known pdf. This program can also be used for instructing mathematical statistics and identifying distribution of the simulated data.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.337-345
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• 1999

The long-tailed, positively skewed exponential distribution can be made into an almost symmetric distribution by taking the exponent of the data. In these situations, to use the traditional shewhart control limits on an individuals chart would be impractical and inconvenient. The transformed data, approximately bell-shaped, can be plotted conveniently on the individuals chart and exponentially weighted moving average chart. In this paper, using modifying statistics with transformed exponential of the data, we give a method for constructing control charts. Selecting method of exponent for individual chart is evaluated. And consider that smaller weight being assigned to the older data as time process and properties and taking method of exponent($\theta$), weighting factor($\alpha$) are suggested. Our recommendation, on the basis result of simulation, is practical method for EWMA chart.

• Journal of the Korea Safety Management & Science
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• v.5 no.3
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• pp.11-20
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• 2003

An agriculture which is one of the national security industry, has recognized the importance. International country have attention to the automatization of machine for the improvement of agriculture. However, because of modernization of agriculture, the rate of accurrence about agriculture accident has increased dramatically. Especially the rate of accurence of agricultural accident is higher than the other industrial accident in the developed country. Because of these reasons, developed country has efforted to the agriculture system about safety. Australia law for the safety system of agriculture is very well and the rate of accident in the self-management agriculture is included in the statistics of industrial But The rate of accident in self-management agriculture is very higher In future we have to try new method about Agricuture Safety of Korea.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.36
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• pp.253-263
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• 1995

In parameter design, Taguchi's stated objective is to find the setting of product or process design parameters that minimize average quadratic loss-that is, the average squared deviation of the response from its target value. Yet in practice to choose the settings of design parameters he maximizeds a set of measures called signal-to-noise(SN) ratios. In general, Taguchi gave no justification for the use the SN ratios and no explanation of why the two-step procedure that he recommened will minimize average loss. The purpose of this study is comparing and analyzing of performance statistics by Leon et al(PerMIA), Box(Transformation theory), Vining & Myers(Dual Response Systems) and Taguchi(Signal-to-Noise ratios).

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.3
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• pp.333-343
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• 1998

This paper proposes variable stream and sample size(VSSS) group control charts in which both the number of streams selected for sampling and sample size from each of the selected streams are allowed to vary based on the values of the preceding sample statistics. The proposed charts select a small portion of streams and take samples of size n = 1 if both the largest and smallest of sample means fall between the lower and upper threshold limits, and select a large portion of streams and take samples of size n > 1 otherwise. A Markov chain approach is used to derive the formulas for evaluating the performances of the proposed charts. Numerical comparisons are made between the VSSS and fixed stream and sample size(FSSS) group control charts.