• 대한수학회지
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• 제36권5호
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• pp.923-943
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• 1999

In this paper we consider functionals of the empirical age distribution of supercritical Bellman-Harris processes. Let f : R+ longrightarrow R be a measurable function that integrates to zero with respect to the stable age distribution in a supercritical Bellman-Harris process with no extinction. We present sufficient conditions for the asymptotic normality of the mean of f with respect to the empirical age distribution at time t.

• 대한수학회지
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• 제36권1호
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• pp.139-157
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• 1999

Consider a supercritical Bellman-Harris process evolving from one particle. We superimpose on this process the additional structure of movement. A particle whose parent was at x at its time of birth moves until it dies according to a given Markov process X starting at x. The motions of different particles are assumed independent. In this paper we show that when the movement process X is standard Brownian the proportion of particles with position $\leq${{{{ SQRT { t} }}}} b and age$\leq$a tends with probability 1 to A(a)$\Phi$(b) where A(.) and $\Phi$(.) are the stable age distribution and standard normal distribution, respectively. We also extend this result to the case when the movement process is a Levy process.

• 유통과학연구
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• 제13권10호
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• pp.51-56
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• 2015

Purpose - This study examines Chinese P2P investment decision processes from a behavioral economics approach. Research design, data, and methodology - We analyze the online P2P investment product purchase decisions of 241 respondents in China, March 2015 to May 2015. T-tests were conducted to determine whether the framing effect influenced investor investment preferences. The Association Rule was used to identify the framing effect of respondent demographic characteristics on joint decisions regarding stable or risky investment products. Results - There are significant differences between the two groups (positive framing and negative framing) and their product-choosing behavior. In the positive framing group, female investors, young investors, investors with non-financial occupations and with limited or no experience, preferred stable P2P investment products. In contrast, in the negative framing group, investors with extensive investment experience preferred risky investment products. Conclusions - The framing effect influences investor choices in online P2P investment products. It is necessary to implement comprehensive supervision and full information disclosure regarding P2P investment products. P2P investment websites can also adopt different marketing strategies according to investor gender and age.

• 한국분말재료학회지
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• 제12권4호
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• pp.303-308
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• 2005

Various kinds of Mg-Zn-Ca base alloys were rapidly quenched via melt spinning process. The meltspun ternary and quaternary alloy ribbons were heat-treated, and then the effects of additional elements on age hardening behavior and phase change of precipitates were investigated using Vickers hardness tester, XRD, and TEM equipped with EDS system. In ternary alloys, age hardening was mostly due to the distribution of $Mg_6Ca_2Zn_3$ and $Mg_2Ca$. The stable phases of precipitates were varied according to the aging temperature and the alloy composition. With the increase of Ca content, $Mg_2Ca$ precipitates were detected more than $Mg_6Ca_2Zn_3$ precipitates. In quaternary alloys, the precipitates taken from Mg-Zn-Ca-Co were identified as new quaternary phase, whereas those taken from Mg-Zn-Ca-Zr as MgZnCa containing Zr. In general, the ternary alloy showed higher peak hardness and thermal stability than the quaternary considering the total amounts of the solutes. It implies that the structure of precipitate should be controlled to have the coherent interface with the Mg matrix.

• The Journal of Asian Finance, Economics and Business
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• 제5권4호
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• pp.213-223
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• 2018

The interest in decrepitude expanded by graying is gradually growing in modern society. Moreover, he concern over decrepitude along with healthy mind and body is increasing. Therefore, there are many concerns and efforts toward physical and mental health. In addition, the interest in and effort for appearance health and value is rising as well as physical and mind health. The middle age is the most stable age based on the economic and social status that had been achieved through the life, but it is the most stressful age due to physical health problem and appearance ageing. There are many advanced studies for self-esteem and life satisfaction in old age by using hair, skin-care, cosmetic, nail-art among beauty related fields but studies on self-esteem and perception of successful ageing through user satisfaction of beauty service is lacking. This study is aiming to verify empirically the positive effect of self-esteem improvement through user satisfaction of beauty service on perception of successful ageing for middle-aged over 50 years old. The study has assumed that the higher middle-aged's satisfaction of beauty service is, the more self-esteem improves and there has a mediated effect to contribute successful ageing.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.973-978
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• 2011

In this study, effects due to differences of creep and shrinkage which is caused by material differences such as concrete characteristic and age in an asymmetric PSC box girder were evaluated. For this purpose the prestress distribution, creep and shrinkage were analyzed with the FE analysis program, LUSAS 14.3. As a result of the prestress, the stress distribution was stable. In case of the analysis result which was conducted with 1,000 days response time, the shear stress between PC section and CIP section is satisfied with design shear strength.

• International Journal of Reliability and Applications
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• 제3권1호
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• pp.1-16
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• 2002

In reliability engineering, the bathtub-shaped hazard rates play an important role in survival analysis and many other applications as well. For the bathtub-shaped, initially the hazard rate decreases from a relatively high value due to manufacturing defects or infant mortality to a relatively stable middle useful life value and then slowly increases with the onset of old age or wear out. In this paper, we present a new two-parameter lifetime distribution function, called the Loglog distribution, with Vtub-shaped hazard rate function. We illustrate the usefulness of the new Vtub-shaped hazard rate function by evaluating the reliability of several helicopter parts based on the data obtained in the maintenance malfunction information reporting system database collected from October 1995 to September 1999. We develop the S-Plus add-in software tool, called Reliability and Safety Assessment (RSA), to calculate reliability measures include mean time to failure, mean residual function, and confidence Intervals of the two helicopter critical parts. We use the mean squared error to compare relative goodness of fit test of the distribution models include normal, lognormal, and Weibull within the two data sets. This research indicates that the result of the new Vtub-shaped hazard rate function is worth the extra function-complexity for a better relative fit. More application in broader validation of this conclusion is needed using other data sets for reliability modeling in a general industrial setting.

• 산업진흥연구
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• 제5권1호
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• pp.13-20
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• 2020

본 연구는 재활용수의 선택적 자동공급이 가능한 플라스틱류 양변기 소비자 선호도에 관한 연구로서 연구분석 결과를 요약하면 다음과 같다. 첫째, 성별, 연령대별 플라스틱류 양변기 디자인 외형에 대한 선호도는 성별에서는 남녀 모드 C 타입을 선호하였고, 카이제곱 검정결과 자유도가 2일 때 유의확률은 .044로 유의성이 P<.05이므로 통계적으로 유의한 것으로 확인 할 수 있었다. 연령에서는 10대, 40대, 50대 이상은 C 타입, 20대, 30대는 B 타입을 선호하는 것으로 분석되었으나 통계적으로 유의하지 못한 것으로 분석되었다. 둘째, 일반적 특성에 따른 외형디자인 기준에 대한 선호도의 집단 간 차이는 성별, 연령, 지역, 학력, 연봉에서모두 안정성(안정적인 외관)을 선호하였으나, 카이제곱 검증 결과, 통계적으로 유의하지 못한 것으로 나타나 집단 간 차이는 없는 것으로 분석되었다. 본 연구는 플라스틱류 소재의 양변기를 제품화함으로써 주요 생산경비 절감 등 경쟁력 및 생산성 향상을 높이는데 본 연구의 시사점이 있다.

• Journal of Preventive Medicine and Public Health
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• 제55권2호
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• pp.164-172
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• 2022

Objectives: We aimed to estimate the space-time distribution of the risk of suicide mortality in Iran from 2006 to 2016. Methods: In this repeated cross-sectional study, the age-standardized risk of suicide mortality from 2006 to 2016 was determined. To estimate the cumulative and temporal risk, the Besag, York, and Mollié and Bernardinelli models were used. Results: The relative risk of suicide mortality was greater than 1 in 43.0% of Iran's provinces (posterior probability >0.8; range, 0.46 to 3.93). The spatio-temporal model indicated a high risk of suicide in 36.7% of Iran's provinces. In addition, significant upward temporal trends in suicide risk were observed in the provinces of Tehran, Fars, Kermanshah, and Gilan. A significantly decreasing pattern of risk was observed for men (β, -0.013; 95% credible interval [CrI], -0.010 to -0.007), and a stable pattern of risk was observed for women (β, -0.001; 95% CrI, -0.010 to 0.007). A decreasing pattern of suicide risk was observed for those aged 15-29 years (β, -0.006; 95% CrI, -0.010 to -0.0001) and 30-49 years (β, -0.001; 95% CrI, -0.018 to -0.002). The risk was stable for those aged >50 years. Conclusions: The highest risk of suicide mortality was observed in Iran's northwestern provinces and among Kurdish women. Although a low risk of suicide mortality was observed in the provinces of Tehran, Fars, and Gilan, the risk in these provinces is increasing rapidly compared to other regions.

• The Korean Journal of Ecology
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• 제16권1호
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• pp.75-91
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• 1993

Structure and dynamics of Abies koreana community in Mt. Gaya were studied to provide the basic data for conservation of Abies koreana community, an endemic species in Korea. A. koreana community of this study site was composed of tree layer (4~7m), subtree layer (2~4m), shrub layer (1~2m), and herb layer (below 1m). The heights of tree and subtree layers were low. Floristic composition showed that this study site was subalpine and dry site. In frequency distribution diagram of diameter classes of major species consisting of A. koreana community, those of both A. koreana and other species showed reverse J-shaped types. From these results, it was estimated that A. koreana community of this site might be maintained continuously as a stable climax state like present state. In the spatal distribution diagram of major species, saplings of A. koreana were established under the canopy of A. koreana and Pinus koraiensis and under the dead tree of A. koreana. From these results, it was known that A. koreana saplings were recruited before the community was disturbed and regeneration was accomplished by advance regeneration pattern, in which these saplings established before occurrence of disturbance fill with open site originated from death of mature tree. Growth of annual rings was variable among individuals, it was estimated that such variation was originated in that growth of each individual relates to microclimatic conditions rather than macroclimatic ones. Ecological longevity of A. koreana in this study site estimated by disturbance types and age of dead trees was about 120 years.