• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.857-870
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• 2017

The use of shield TBM is gradually increasing due to the urbanization of social infrastructures. Reliable estimation of advance rate is very important for accurate construction period and cost. For this purpose, it is required to develop the prediction model of advance rate that can consider the ground properties reasonably. Based on the database collected from field, statistical prediction procedure for field penetration index (FPI) was modularized in this study to calculate penetration rate of shield TBM. As output parameter, FPI was selected and various systems were included in this module such as, procedure of eliminating abnormal dataset, preprocessing of dataset and ridge regression with best subset selection. And it was finally validated by using field dataset.

• 한국해양학회지
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• v.27 no.1
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• pp.35-45
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• 1992

This paper is concerned with the development and application of a stochastic model for predicting E1 nino phenomenon. For this, first a general criterion for determining E1 nino phenomenon, including period and strength, which is based on partial sum of monthly sea surface temperatures (SST) anomalies, is proposed, Secondly, the annual fluctuations, periodicity and dependence of monthly mean of equatorial Pacific SST during the period 1951-1990 are analyzed. Based on these, time series nonlinear regression model for the prediction of SST have been derived. A statistical procedure for using the model to predict the SST have been derived. A statistical procedure for using the model to predict the SST level is also proposed.

• Communications for Statistical Applications and Methods
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• v.17 no.5
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• pp.697-712
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• 2010

This paper is concerned with the statistical analysis and development of stochastic models for the demand for life insurance policy loans. For these, firstly the characteristics of the regression trend, periodicity and dependence of the monthly demand for life insurance policy loans are investigated by a statistical analysis of the monthly demand data for the years 1999 through 2008. Secondly, the causal relationships between the demand for life insurance policy loans and the economic variables including unemployment rate and inflation rate for the period are investigated. The results show that inflation rate is main factor influencing policy loan demands. The overall evidence, however, failed to establish unidirectional causality relationships between the demand series and the other variables under study. Finally, based on these, univariate time series model and transfer function model where the demand series is related to one input series are derived, respectively, for the prediction of the demand for life insurance policy loans. A statistical procedure for using the model to predict the demand for life insurance policy loans is also proposed.

• Proceedings of the Korean Reliability Society Conference
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• 2000.04a
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• pp.81-87
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• 2000

최근 신뢰성 가속 시험 분야에서 제품의 잠재 또는 취약 부위를 단기간에 효과적으로 검출할 수 있도록 개발된 HALT(Highly Accelerated Life Test) 기술을 당사에서 생산 중인 영상제품에 적용하였다. 적용 결과 HALT는 기존의 보증용 가속 시험에서 추구하는 고장 데이터의 통계적인 수명 예측이나 고장률 추정의 절차를 따르지 않고도 한계 스트레스 시험을 이용하여 제품의 잠재적인 취약부위를 단시간에 효과적으로 촉진하고 들춰 내어 전자 제품에 적용할 수 있는 유용한 가속 스트레스 시험 기술임이 입증되었다.

• The Korean Journal of Applied Statistics
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• v.30 no.5
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• pp.633-645
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• 2017

This study proposes a statistical procedure for analyzing container ship operation data that can help determine fuel consumption patterns. We first investigate the features that affect fuel consumption and develop the prediction model to find current fuel consumption. The ship data can be divided into two-type data. One set of operation data includes sea route, voyage information, longitudinal water speed, longitudinal ground speed, and wind, the other includes machinery data such as engine power, rpm, fuel consumption, temperature, and pressure. In this study, we separate the effects of external force on ships according to Beaufort Scale and apply a partial least squares regression to develop a prediction model.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.6
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• pp.95-101
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• 2013

Social media has many advantages. It can gain latest information with real time, be spread rapidly, easily be reproduced and distributed regardless of its form. These advantages can result in real time predictions using the latest information, which is possible due to the increase in social demand for more quick and accurate economic variable predictions. In this paper we adopted ARIMAX and ECM model to predict the unemployment rate and as a social information we used the Google Index provided by Google Trend. Also we used News Index as a domestic social information. The process of fitting statistical model considered in this paper can be adopted to predict various socio/economic indices as well as unemployment rate.

• Journal of Korean Society of Forest Science
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• v.90 no.2
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• pp.176-183
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• 2001

Loblolly pine (Pinus taeda L.) is the most economically important timber producing species in the southern United States. Much attention has been given to predicting diameter distributions for the solution of multiple-product yield estimates. The three-parameter Weibull diameter distribution yield prediction systems were developed for loblolly pine plantations. A parameter recovery procedure for the Weibull distribution function based on four percentile equations was applied to develop diameter distribution yield prediction models. Four percentiles (0th, 25th, 50th, 95th) of the cumulative diameter distribution were predicted as a function of quadratic mean diameter. Individual tree height prediction equations were developed for the calculation of yields by diameter class. By using individual tree content prediction equations, expected yield by diameter class can be computed. To reduce rounding-off errors, the Weibull cumulative upper bound limit difference procedure applied in this study shows slightly better results compared with upper and lower bound procedure applied in the past studies. To evaluate this system, the predicted diameter distributions were tested against the observed diameter distributions using the Kolmogorov-Smirnov two sample test at the ${\alpha}$=0.05 level to check if any significant differences existed. Statistically, no significant differences were detected based on the data from 516 evaluation data sets. This diameter distribution yield prediction system will be useful in loblolly pine stand structure modeling, in updating forest inventories, and in evaluating investment opportunities.

• The Korean Journal of Applied Statistics
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• v.5 no.1
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• pp.59-80
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• 1992

This paper is concerned with the development and application of a stochastic model for winter air-temperature of Seoul area. The annual and interannual flucturations of the regression trend, periodicity and dependence of the air-temperature are analyzed based on the data during the past 30 years(1959-1989). A statistical procedure for using the stochastic model to predict the air-temperature is proposed. Some statistical characteristics of winter air-temperature including unusual air-temperature and Samhansaon are also discussed.

• The Journal of Korean Association of Computer Education
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• v.3 no.2
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• pp.107-114
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• 2000

In this study, a program for statistics education is developed. This program deals with statistical hypothesis testing which is indispensible to demonstrate the research hypothesis. Statistical inference which is the process of using data obtained from a sample to make inference about the characteristics of a population is an essential concept to peoples to learn or use statistics. But in practice, there are many cases of wrong application and peoples think that statistics is hard to understand. Therefore, it is very important subject to teach easily and rightly statistics, specially elementary statistics. This program is developed especially for non-specialist. This program under multimedia environment which includes sound, video, animation etc. can interest students greatly. It doesn't show only the result but make it possible for students to execute the program by stages. By executing it, the students can understand the method and meaning of statistical hypothesis testing naturally.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1705-1713
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• 2010

The reliable fatigue life for hybrid composite joint structures was estimated by a statistical method for evaluating fatigue life; the results of the fatigue test varied widely. Cyclic bending tests were performed on a cantilever beam with a hybrid composite joint, which was developed for the body of a low-floor bus. In order to estimate the fatigue life of the hybrid composite joint structure by comparing the data obtained during the fatigue tests, the most suitable probabilistic density function among the normal, lognormal, and Weibull distributions was selected. The probabilistic-stress-life (P-S-N) curves calculated by using the selected Weibull distribution was suggested for process of statistical fatigue life estimation and reliability design.