• 한국자동차공학회논문집
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• 제14권3호
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• pp.133-141
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• 2006

The Low cycle fatigue behavior of 11.7Cr-1.1Mo heat-resisting steel has been investigated under strain-controlled conditions with mean stresses at room temperature and $300^{\circ}C$. For the tensile mean stress test, the initial high tensile mean stress generally relaxed to zero at room temperature, however, at $300^{\circ}C$ initial tensile mean stress relaxed to compressive mean stress. Low cycle fatigue lives under mean stress conditions are usually correlated using modifications to the strain-life approach. Based on the fatigue test results from different stain ratio of -1, 0, 0.5, and 0.75 at room temperature and $300^{\circ}C$, the fatigue damage of the steel was represented by using cyclic strain energy density. Total strain energy density considering mean stress indicated well better than not considering mean stress at $300^{\circ}C$. Predicted fatigue life using Smith-Watson-Topper's parameter correlated fairly well with the experimental life at $300^{\circ}C$.

• International Journal of Advanced Culture Technology
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• 제3권2호
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• pp.161-170
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• 2015

Mean separated histogram equalization in order to preserve the original mean brightness has been proposed. To provide the minimum mean brightness error after the histogram modification, the input image's histogram is successively divided by the factor of 2 until the mean brightness error is satisfied the defined threshold. Then each divided group or sub-histogram will be independently equalized based on the proportional input mean. To provide the overall minimum mean brightness error, each group will be controlled by adding some certain pixels from the adjacent grey level of the next group for giving its mean near by the corresponding the divided mean. However, it still exists some little error which will be put into the next adjacent group. By successive dividing the original histogram, we found that the absolute mean brightness error is gradually decreased when the number of group is increased. Therefore, the error threshold is assigned in order to automatically dividing the original histogram for obtaining the desired absolute mean brightness error (AMBE). This process will be applied to the color image by treating each color independently.

• 한국대기환경학회지
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• 제6권1호
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• pp.22-30
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• 1990

The contents of benzo(a)pyrene (Bap.), Pyrene(Py) and Perylene(Pery) were determined by one-dimensional dual band thinlayer chromatogragphy and spectrofluorophotometer in soil samples from road at 36 places of Ulsan and 6 places of Seoul from April to May, 1984. The concents were as follows: 1. Ulsan city : Bap. 0.05-3.66 $\mu$g/g ; mean 1.07 $\mu$g/g Py. 0.60-11.01 $\mu$g/g ; mean 4.34 $\mu$g/g Pery. 0.94-5.48 $\mu$g/g ; mean 1.83 $\mu$g/g 1) Industrial area : Bap. 0.03-3.66 $\mu$g/g ; mean 5.28 $\mu$g/g Py. 2.34-9.07 $\mu$g/g ; mean 5.28 $\mu$g/g Pery. 1.01-3.69 $\mu$g/g ; mean 2.09 $\mu$g/g 2) Commercial area : Bap. 0.15-2.27 $\mu$g/g ; mean 0.29 $\mu$g/g Py. 0.06-11.0 $\mu$g/g ; mean 4.04 $\mu$g/g Pery. 1.03-5.48 $\mu$g/g ; mean 1.84 $\mu$g/g 3) Residential area : Bap. 0.05-0.05 $\mu$g/g ; mean 0.29 $\mu$g/g Py. 1.34-5.53 $\mu$g/g ; mean 2.74 $\mu$g/g Pery. 0.94-2.15 $\mu$g/g ; mean 1.18 $\mu$g/g 2. Commerical area in Seoul : Bap. 0.35-1.01 $\mu$g/g ; mean 0.74 $\mu$g/g Py. 9.37-24,44 $\mu$g/g ; mean 18.64 $\mu$g/g Peay. 1.47-2.24 $\mu$g/g ; mean 1.87 $\mu$g/g 3. The areas that had high contents of Benzo(a)pyrene had also high contents of Pyrene and Perylene. 4. The industrial area had the highest contents of polynuclear aromatic hydrocarbons, followed by commercial area and residential area. 5. The contents of Bap. and Pery. in the commercial area were similar in Seoul and Ulsan, while the content of Py. in Seoul was 4 times higher than in Ulsan.

• Journal of the Korean Statistical Society
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• 제32권1호
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• pp.25-32
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• 2003

In this paper, we define the mean life process for the right censored data and show the asymptotic equivalence between two kinds of the mean life processes. We use the Kaplan-Meier and Susarla-Van Ryzin estimates as the estimates of survival function for the construction of the mean life processes. Also we show the asymptotic equivalence between two mean residual life processes as an application and finally discuss some difficulties caused by the censoring mechanism.

• 대한수학회보
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• 제49권1호
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• pp.33-47
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• 2012

In this paper, the log-convexity of another class one-parameter mean is investigated. As applications, some new upper and lower bounds of logarithmic mean, new estimations for identric mean and new inequalities for power-exponential mean and exponential-geometric mean are first given.

• 대한수학회논문집
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• 제34권1호
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• pp.239-251
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• 2019

In this paper we introduce a new formulation of symmetric homogeneous bivariate means that depends on the variation of a given continuous strictly increasing function on (0, ${\infty}$). It turns out that this class of means includes a lot of known bivariate means among them the arithmetic mean, the harmonic mean, the geometric mean, the logarithmic mean as well as the first and second Seiffert means. Using this new formulation we introduce a lot of new bivariate means and derive some mean-inequalities.

• 여성건강간호학회지
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• 제1권2호
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• pp.174-199
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• 1995

This study examined the antenatal care known as Taekyo. The sample consisted of 795 women and 564 men who had be seen in the antenatal care unit, delivery room, or postpartal care unit of general hospitals in Korea between March 20 and April 22, 1995. Data were collected using the "Taekyo questionnaire for childbearing women" and "Taekyo questionnaire for husbands of childbearing women" developed by researchers. Data were self-reported. Data were analyzed using the SPSS PC+ program, and descriptive statistics, T-test, ANOVA, Pearson correlation coefficient were applied. The results of this study were as follows : 1. Encouragement to practice Taekyo was at a relatively high level. Items on Taekyo encouraging behaviors had a mean score of 3.51(33 items 5 point scale). According to the five categories of Taekyo encouraging behaviors, subjects indicated they practice "food intake(mean score 4.02)". "praying(mean score 3.78)", "cumulative virtuous deeds (mean score 3.58)". "mind and body management(mean score 3.47)", "maternal fetal interaction(mean score 3.15)". 2. The childbearing women's practices related to forbidden behaviors by Taekyo were relatively high. Item on forbidden behaviors by Taekyo had a mean score 3.71(43 items 5 point scale). According to the five categories of forbidden behaviors by Taekyo, subjects indicated they practiced "voluntary abstention of drugs(mean score 4.78)," avoiding behaviors(mean score 4.78)," avoiding behaviors(mean score 3.77), "good behaviors(mean score 3.71)", "taboo on fetal death tendency (mean score 3.53)", "taboo on certain intake(mean score 3.47)". 3. The practice score of husbands for childbearing women which related to Taekyo behaviors were relatively high. Item on Taekyo behaviors had a mean score 3.59(33 items 5 point scale). According to the six categories of Taekyo behavior, subjects indicated they practiced "mind and body management(mean score 3.94)", "praying(mean score 3.80)", "support of women’s practice related to Taekyo(mean score 3.66)", "good behaviors(mean score 3.58)", "continency(mean score 3.33)", "paternal fetal interaction (mean score 3.19)". 4. On the childbearing women's perception of Taekyo, most of the subjects(88%) had confidence in the positive effects of Taekyo on Child development. The result showed that the childbearing couples practiced Taekyo behavior relatively often and sincerely and most of the childbearing women had a positive perception of Taekyo's effect on prenatal child development.

• Journal of applied mathematics & informatics
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• 제35권1_2호
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• pp.191-204
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• 2017

A new fifth-order weighted Runge-Kutta algorithm based on heronian mean for solving initial value problem in ordinary differential equations is considered in this paper. Comparisons in terms of numerical accuracy and size of the stability region between new proposed Runge-Kutta(5,5) algorithm, Runge-Kutta (5,5) based on Harmonic Mean, Runge-Kutta(5,5) based on Contra Harmonic Mean and Runge-Kutta(5,5) based on Geometric Mean are carried out as well. The problems, methods and comparison criteria are specified very carefully. Numerical experiments show that the new algorithm performs better than other three methods in solving variety of initial value problems. The error analysis is discussed and stability polynomials and regions have also been presented.

• 한국수학교육학회지시리즈A:수학교육
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• 제49권2호
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• pp.199-221
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• 2010

The purpose of the study were to investigate how secondary pre-service teachers conceptualize arithmetic mean and how their conceptualization was formed for solving the problems involving arithmetic mean. As a result, pre-service teachers' conceptualization of arithmetic mean was categorized into conceptualization by "mathematical knowledge(mathematical procedural knowledge, mathematical conceptual knowledge)", "analog knowledge(fair-share, center-of-balance)", and "statistical knowledge". Most pre-service teachers conceptualized the arithmetic mean using mathematical procedural knowledge which involves the rules, algorithm, and procedures of calculating the mean. There were a few pre-service teachers who used analog or statistical knowledge to conceptualize the arithmetic mean, respectively. Finally, we identified the relationship between problem types and conceptualization of arithmetic mean.

• 한국지진공학회논문집
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• 제23권6호
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• pp.301-309
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• 2019

A methodology to assess seismic fragility of a nuclear power plant (NPP) using a conditional mean spectrum is proposed as an alternative to using a uniform hazard response spectrum. Rather than the single-scenario conditional mean spectrum, which is the conventional conditional mean spectrum based on a single scenario, a multi-scenario conditional mean spectrum is proposed for the case in which no single scenario is dominant. The multi-scenario conditional mean spectrum is defined as the weighted average of different conditional mean spectra, each one of which corresponds to an individual scenario. The weighting factors for scenarios are obtained from a deaggregation of seismic hazards. As a validation example, a seismic fragility assessment of an NPP containment structure is performed using a uniform hazard response spectrum and different single-scenario conditional mean spectra and multi-scenario conditional mean spectra. In the example, the number of scenarios primarily influences the median capacity of the evaluated structure. Meanwhile, the control frequency, a key parameter of a conditional mean spectrum, plays an important role in reducing logarithmic standard deviation of the corresponding fragility curves and corresponding high confidence of low probability of failure (HCLPF) capacity.