• Journal of Information Processing Systems
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• v.10 no.3
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• pp.429-442
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• 2014

In this paper, we investigated the use of seasonal autoregressive integrated moving average (SARIMA) time series models for fault detection in semiconductor etch equipment data. The derivative dynamic time warping algorithm was employed for the synchronization of data. The models were generated using a set of data from healthy runs, and the established models were compared with the experimental runs to find the faulty runs. It has been shown that the SARIMA modeling for this data can detect faults in the etch tool data from the semiconductor industry with an accuracy of 80% and 90% using the parameter-wise error computation and the step-wise error computation, respectively. We found that SARIMA is useful to detect incipient faults in semiconductor fabrication.

• International Journal of Aeronautical and Space Sciences
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• v.1 no.2
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• pp.17-21
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• 2000

In order to correct the strut interference in wind tunnel tests, image methods are conventionally used. Because of their excessive extra runs, some alternatives have been tried to reduce the extra runs. In this study, these alternatives were reviewed and checked by the strut interference evaluation with the panel code, CMARC. The present work shows that the strut interference is free from neither model configuration nor model attitude. This dependency makes the alternatives to the image method unfeasible. The 3-run image method was also evaluated. It worked well even for the exaggerated windshield. At this point, reducing the image runs by neglecting parameters affecting minor influence would be best.

• Journal of the Korea Society for Simulation
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• v.11 no.3
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• pp.1-12
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• 2002

Experimental design in simulation provides an efficient way of economizing simulation runs since a considerable number of simulation runs that originally were planned can be reduced by this approach. This experimental design method is an active area of research together with the output analysis and so no single panacea seems to exist so far. Thus, selection of techniques of experimental design and output analysis more likely depends upon the objective of simulation analysis, budget constraint and sometimes the analyst's subjective judgment. This paper attempts to describe an experimental design methodology for port investment analysis using a case study in a bulk terminal in Korea. Detailed display will be focused on simulation period, warm-up period, the number of replications needed in production runs after brief explanation on the system configuration.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.6
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• pp.33-43
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• 1999

Drought is a serious diaster in agriculutre, especially to upland crops. Hence, the Agricultural Drought Analysis Model (ADAM) that is integratable with GIS was applied to analyae agriculture drought in upland. ADAM is composed of two sub-models , one is a Soil Water Balance Model (SWBM) and the other is a Drougth Analysis Model (DAM) that is based on the Runs theory. The ADAM needs weather data, rainfall data and soil physical characteristics data as input and calculates daily soil moisture contents. GIS was integrated to the ADAM for the calculation of regional soil moisture using digitized landuse map, detaile dsoil map, thiessen network and district boundary . For the agriculutral drought analysis, the ADAM adapt the Runs theory for analyzing drought duration, severity and magnitude . Log-Pearson Type-III probability distribution function and Kolmogorov-Smirnov test were used to test the fitness of good of the model. The integration of ADAM with GIS was successfully implemented and would be operated effectively for the regional drought analysis.

• Journal of the Korean Statistical Society
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• v.33 no.1
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• pp.35-58
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• 2004

For fixed positive integers and $\textit{k}\;(n\;{\geq}\;{\textit{k}}\;+\;2)$, the exact probability distributions of non-overlapping and overlapping patterns of two failures separated by (i) exactly $textsc{k}$ successes, (ii) at least $\textit{k}$ successes and (iii) at most $\textit{k}$ successes have been obtained for Bernoulli independent and Markov dependent trials by using combinatorial technique. The waiting time distributions for the first occurrence and the $r^{th}$ (r > 1) occurrence of the patterns have also been obtained.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.623-628
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• 1990

This paper describes the design of EFbus(ETRI Fieldbus), EFbus was designed from the interim results of international Fieldbus standardization in IEC (International Electrotechnical Commission) and proposals of many companies. The design was performed and described on the basis of three layered architecture. Application layer S/W runs on IBM PC and provides services which is similar ED MMS in MAP to user application Data linklayer runs on Intel's iDCX96 real time executive and uses centralized media accesscontrol method. Physical layer uses Manchester encoding & decoding, twisted pair fines and RS485 electrical standard.

• Journal of Korean Institute of Industrial Engineers
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• v.13 no.2
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• pp.97-103
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• 1987

Skip-Lot sampling plan is formulated in terms of renewal process. This approach facilitates studying the average outgoing quality in a short production run of length t, AOQ (t). By numerical studies it is found that the long-run average outgoing quality (AOQ) greatly overestimates AOQ (t) for short runs.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.1
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• pp.26-33
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• 2012

Competition between air transportation and railways has grown fiercer in major countries around the world with the rise of high-speed railways. In South Korea, air passenger travel has been rapidly decreasing since the initial launch of the Seoul-Pusan KTX line in 2004 and second opening that followed in 2010. Further expansion of the high-speed railway is expected. At present, research efforts to verify the validity of constructing an underwater express railway tunnel between Ho-nam and Jeju Island are taking place. Considering the possible high speed railway connection between Seoul and Jeju Island, this thesis has analyzed the choice behavior of existing passengers of the major and low-cost carriers. For this, Stated Preference (SP) research has been performed for three variables, including fare, travel time and the number of runs, to estimate the substitution rate of each of the three variables. Binomial Logit Model has been estimated with the obtained data. The estimation of the model has found that airline passengers of major and low-cost carriers are willing to pay approximately 7,200 KRW and 5,000 KRW, respectively, to reduce travel time by one hour. If the number of runs in one day increases, it has been estimated that the passengers are willing to pay additional fares of about 390 KRW and 30 KRW, respectively. On the other hand, the substitution rate between the number of runs and the travel time was found to be somewhat insignificant. If the construction of the Seoul-Jeju line progresses in the future, this study could be used as preliminary data for determining fares, travel time and the number of runs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.247-250
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• 2006

Maximizing the productivity in reactive ion etching, early detection of process equipment anomaly became crucial in current high volume semiconductor manufacturing environment. To address the importance of the process fault detection for productivity, support vector machines (SVMs) is employed to assist the decision to determine process faults in real-time. SVMs for eleven steps of etching runs are established with data acquired from baseline runs, and they are further verified with the data from controlled (acceptable) and perturbed (unacceptable) runs. Then, each SVM is further utilized for the fault detection purpose utilizing control limits which is well understood in statistical process control chart. Utilizing SVMs, fault detection of reactive ion etching process is demonstrated with zero false alarm rate of the controlled runs on a run to run basis.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.938-945
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• 2005

For elucidating excessive growth of biofilm that subsequently leads to the clogging problem in a small town's sewer lines of Wisconsin, the FISH method was employed. At the beginning of the simulated experiments, ${\beta}$-subclass proteobacteria prevailed in runs fed with industrial wastewater, while ${\gamma}$-subclass proteobacteria dominated in runs with domestic wastewater. However, the bacterial community structure changed significantly over six weeks; Cytophaga-Flavobacterium (CF)­group bacteria dominated in most runs fed with the small town's wastewater regardless of their source, while CF-group decreased strongly in run fed with domestic sewage from another city (Madison). It was also microscopically confirmed that most of those clogging materials was toilet tissue, which in turn may lead to vigorous growth of cellulose-degrading CF-group bacteria. This dominant presence of CF-group bacteria in the small town's sewer indicates that the main constituent of biofilm, toilet tissue (cellulose) in sewage, might have induced the unique pattern of their microbial community structure. Therefore, it suggests that molecular technique is useful for monitoring the clogging problems in sewer lines.