• Journal of Korean Institute of Industrial Engineers
• /
• v.7 no.1
• /
• pp.33-36
• /
• 1981

An equipment is subject to shocks which occur randomly according to a Poisson process. The equipment fails when the total cumulative damage reaches a certain prescribed level. An optimal preventive replacement policy is presented when the level of cumulative damage cannot be checked. Renewal theory is used to obtain the results and a case example is presented.

• Communications for Statistical Applications and Methods
• /
• v.26 no.6
• /
• pp.623-633
• /
• 2019

This paper proposes two distance measures between two cumulative hazard functions that can be obtained by comparing their difference and ratio, respectively. Then we estimate the measures and present goodness of t test statistics. Since the proposed test statistics are expressed in terms of the cumulative hazard functions, we can easily give more weights on earlier (or later) departures in cumulative hazards if we like to place an emphasis on earlier (or later) departures. We also show that these test statistics present comparable performances with other well-known test statistics based on the empirical distribution function for an exponential null distribution. The proposed test statistic is an omnibus test which is applicable to other lots of distributions than an exponential distribution.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.3
• /
• pp.345-358
• /
• 2014

For introducing the groundwater quality assessment using background concentration of groundwater, several methods had been studied to estimate the background concentration of groundwater and to suggest the background concentration of study area. Some methods such as Box whisker plot, Percentile and Cumulative probability distribution had been adopted to estimate background concentration, and it was evaluated that the Cumulative probability distribution method presents more reasonable background concentration because it can consider the data distribution. So we estimated the background concentration of study area using cumulative probability distribution method. We suggested the background concentration for each hydrogeology respectively in case hydrogeological water quality similarity is very low.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.8
• /
• pp.1915-1926
• /
• 1995

The Fatigue characteristics of 8-harness satin woven CFRP composites with a circular hole are experimentally investigated under constant amplitude tension-tension loading. It is found in this study that the fatigue damage accumulation behavior is very random and history-independent, and the fatigue cumulative damage is linearly related with the mean number of cycles to a specified damage state. From these results, it is known that the fatigue characteristics of CFRP composites satisfy the basic assumptions of Markov chain theory and the parameter of Markov chain model can be determined only by mean and variance of fatigue lives. The predicted distribution of the fatigue cumulative damage using Markov chain model shows a good agreement with the test results. For the fatigue life distribution, Markov chain model makes similar accuracy to 2-parameter Weibull distribution function.

• Proceedings of the KSME Conference
• /
• 2001.06a
• /
• pp.193-198
• /
• 2001

The feasibility of the acoustic emission technique in predicting the residual fatigue life of STS304 stainless steel is presented. Acoustic emission was continuously monitored during the fatigue tests. Considerable acoustic emission occurred during the first few cycles. Acoustic Emission increased rapidly at about 90% of the fatigue life, clear and ample warning of impending fatigue failure was observed. Fatigue damage accumulation was evaluated in terms of an AE cumulative counts. The AE cumulative counts may be taken as an indicator of fatigue cumulative damage. Fatigue damages corresponding to 20, 40, 60 and 80% of the total life were induced at a cyclic stress amplitude. The specimens with and without fatigue damage were subjected to tensile tests. In tensile tests, the total cumulative counts were reduced with increasing fatigue damage. It was observed that the residual tensile strength of material did not change significantly with prior cyclic loading damages.

• Speech Sciences
• /
• v.13 no.4
• /
• pp.127-140
• /
• 2006

This study examined acoustic characteristics of 900 CV syllables produced by five English native speakers. Those target syllables were produced between the syllable /ba/ twenty times. The syllables were segmented and normalized by the maximum intensity value of each syllable and were divided into consonant or vowel sections by a few visible acoustic criteria. Intensity values were collected at 100 relative time points per syllable. Also, cumulative intensity values and consonant and vowel durations along with the ratio of a consonant to each syllable were measured using Praat scripts. Results showed as follows: Firstly, the consonantal section amounted to a quarter of the syllable in terms of both the cumulative intensity and duration. Secondly, the consonantal ratio by the cumulative intensity was similar to that by the duration. Finally, the sum of the cumulative intensity values in each syllable partially coincided with the consonant order by the current sonority scale. Further studies would be desirable on more reliable acoustical measurements and sophisticated perceptual experiments on the English syllables.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1995.05a
• /
• pp.893-898
• /
• 1995

The cumulative deposition of Pu-238 and Pu-239,240 by the end of 1994 in undisturbed for the last 40 years, was determined at 9 sites in Korea. The cumulative deposition of Pu-238 and Pu-239 ranged from 0.76 to 3.77 and from 18.42 to 101.84 $Bqm^{-2}$, respectively. The mean values of the cumulative deposition of Pu-238 and Pu-239,240 were 2.16 and 54.75 $Bqm^{-2}$, respectively. These values are close to the value of worldwide fallout. No significant contribution to the cumulative deposition of Pu-238 and Pu-239,240 originating from the Chernobyl accident was found at my site.

• Korean Journal of Child Studies
• /
• v.35 no.2
• /
• pp.43-61
• /
• 2014

The main purpose of this study was to investigate the paths from the cumulative risk factors to infant's development at 24 months of age via the mediation of maternal parenting behaviors. The data consisted of 3 year's worth of data harvested from 1802 families participating in the Panel Study on Korean Children (PSKC). The results revealed that cumulative family risk factors tended to stay in the family in relatively stable ways. Early risk factors significantly predicted later risk factors. Cumulative risk factors were negatively associated with the parenting styles of mothers, which in turn, significantly predicted the development of the infants concerned. Statistical tests supported the notion that mothers' parenting behavior is the mediator of the relation between family risk factors and infant's developmental outcomes.

• Journal of Information Technology Applications and Management
• /
• v.20 no.4
• /
• pp.207-219
• /
• 2013

The study examined relational marketing in terms of transaction specific satisfaction and cumulative satisfaction in the professional sport industry. The study evaluated the motivation of spectators visiting professional baseball games in 2012 and the satisfaction factors of relationship marketing. In this study, the satisfactions were considered in terms of single satisfaction associated with transaction and gradual satisfaction associated with customer loyalty. The relationship marketing was established considering each factor of marketing strategies, facility, game performance and entertainment. The study categorized the factors for customers to visit games as facility, game performance and entertainment with marketing strategies. The study found out that the customer satisfaction was related with both transaction specific satisfaction and cumulative satisfaction where cumulative one is longer term related. Moreover, cumulative satisfaction will be more related with the long term team financial performance.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.6
• /
• pp.746-751
• /
• 2014

This paper presents a method to calculate a sag cumulative table and density table based on the area of vulnerability to voltage sags. The expected sag performance at sensitive load points can be easily assessed through the calculation of the sag cumulative table and density table. However, the calculation of the tables regarding large power systems is very difficult task. Therefore, an efficient method for calculating the tables is needed. In this paper, the improved method to determine the areas of vulnerability is addressed and the method to calculate the tables based on the area of vulnerability is also described. The proposed scheme can be efficiently used to assess the voltage sag performance at sensitive load points in large power systems.