• Journal of Environmental Science International
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• v.1 no.2
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• pp.25-31
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• 1992

Authors Investigated the particulate size distribution in work environment of Banwol and Changwon industry complex. Size distributions of particles exposured to workers in welding and in grounding process were evaluated by personal cascade impactors. Personal air samplers with personal cascade impactor were attached to the workers. The mass median diameter measured in welding sites were 0.3 to 3.BUm and in grinding sites were 1.5 to 2.6htn. Respirable matter fractions were ranged 32.67 to 65.055. Respirable matter fractions were calculated from the sixte distribution data by the respirable particle mass of the ACGIH criteria. The study relating to characteristics of particle of other industries and particulate sixte distribution is more needed in the near future

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.628-633
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• 2020

This paper presents an analysis of the shelf-life management program of the long-term storage one-shot system. The one-shot system is mainly maintained with long-term storage or non-operating status and is operated once at execution of the mission. The function corresponding to one-shot is mainly operated through a shelf-life item such as an explosive. The performance and characteristics of shelf-life item are subject to change as the storage period passes. Therefore, shelf-life management for maintaining good condition is very important during long-term storage, and criteria for management is necessary. We present a method for optimizing shelf-life extension by comparing criteria for management with current reliability. Next, the shelf-life evaluation schedule was decided by utilizing the reliability function of exponential distribution and Weibull distribution. Continuously accumulated test data from the shelf-life evaluation were analyzed, and the parameter of distribution was updated. The extension or expiration of shelf-life was selected by monitoring changes in reliability. In addition, we confirmed the applicability of the presented shelf-life management program by applying ASRP test data of the one-shot system K000 fuse.

• Communications for Statistical Applications and Methods
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• v.19 no.2
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• pp.277-286
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• 2012

For credit assessment models, the ROC curves evaluate the classification performance using two univariate cumulative distribution functions of the false positive rate and true positive rate. In this paper, it is extended to two bivariate normal distribution functions of default and non-default borrowers; in addition, the bivariate ROC curves are proposed to represent the joint cumulative distribution functions by making use of the linear function that passes though the mean vectors of two score random variables. We explore the classification performance based on these ROC curves obtained from various bivariate normal distributions, and analyze with the corresponding AUROC. The optimal threshold could be derived from the bivariate ROC curve using many well known classification criteria and it is possible to establish an optimal cut-off criteria of bivariate mixture distribution functions.

• Bulletin of the Korean Mathematical Society
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• v.51 no.3
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• pp.691-700
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• 2014

We study normality for families of meromorphic functions which is related to an extended version of a Hayman's conjecture on value distribution, and prove several normality criteria for meromorphic functions and certain non-homogeneous differential polynomials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.515-524
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• 2014

In this paper, The investment prioritization model was investigated for keeping the service level of mooring facilities more than the target level of management with a limited budget in the right time. Network level prioritization criteria of the national scale was developed to take into criteria index and quantitative evaluation, management authority's opinion. Delphi method was conducted maintenance exports of mooring facilities over twice for verifying the validity and adequacy. In order to improve the objectivity of criteria, the criteria for evaluating the utilization of port facilities is presented form yearly facility traffic/facility's length, the result of the analysis of facility traffic data. The investment prioritization criteria of mooring facilities is expected to be utilized for more efficient and national budget distribution applied to the maintenance budget plan of nationwide.

• Proceedings of the SAREK Conference
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• 2004.11a
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• pp.69-69
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• 2004

• Communications for Statistical Applications and Methods
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• v.19 no.4
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• pp.629-638
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• 2012

We propose some methods to obtain optimal thresholds and classification functions by using various cutoff criterion based on the bivariate ROC curve that represents bivariate cumulative distribution functions. The false positive rate and false negative rate are calculated with these classification functions for bivariate normal distributions.

• Journal of the Korea Fashion and Costume Design Association
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• v.5 no.3
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• pp.111-123
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• 2003

This study is designed to understand evaluation criteria for garment depending on demographic factors among college students in Yanbian, China. Questionnaire was used for measurement tools to study the subject of the thesis. The main study was conducted against 450 college students from May 17 to June 5, 2001. The data for the study were analyzed using SAS PC program for frequency distribution, percentage, t-test, and one way ANOVA. The evaluation criteria for garment are affected by demographic factors such as gender, average monthly household income, monthly expense for clothing. The result was showed as follows: The evaluation criteria for garment based on gender showed almost no meaningful different between male and female college students. Means on factors considered highly in selecting clothes was studied. The result shows that 'fit to the body, 'quality', 'color' and 'pattern' are considered most highly and 'harmony with other clothes', 'after service', design' 'easy to manage' and 'price' are considered relatively highly, but 'brand' and 'trendy fashion' were not considered highly. A meaningful difference was showed only in one area-trendy fashion-among three different income level groups. Those with an average monthly household income between 500 and 2,000yuan showed a highest tendency compared to those with above 2,000yuan and those with 500yuan. In terms of evaluation criteria for garment based on monthly expense for clothing, 'brand' is the only area which showed a meaningful difference. Respondents with monthly clothing expense of above 100yuan showed a higher means than those with below 100yuan.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.2
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• pp.321-329
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• 2012

In this study, statistical analysis under both stationary and non-stationary climate was conducted for rainfall data measured in Seoul. Generalised Extreme Value (GEV) distribution and Gumbel distribution were used for the analysis. Rainfall changes under the non-stationary climate were estimated by applying time variable (t) to location parameter (${\xi}$). Rainfall depths calculated in non-stationary climate increased by 1.1 to 6.2mm and 1.0 to 4.6mm for the GEV distribution and gumbel distribution respectively from those stationary forms. Changes in annual maximum rainfall were estimated with rate of change in the location parameter (${\xi}1{\cdot}t$), and temporal changes of return period were predicted. This was also available for re-evaluating the current sewer design return period. Design criteria of sewer system was newly suggested considering life expectance of the system as well as temporal changes in the return period.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.611-622
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• 2007

The purpose of this research was to three-criteria landuse-pattern, developing density, NDVI which were related to the heat island and find the distribution characteristic of urban surface temperature and urban heat island effects. The results of this study were as follows. According to the analysis of surface temperatures, the first grade was the outside-city like a mountain and its temperature was less than $12.18^{\circ}C$. The fifth grade was the downtown industrial area and its temperature was more than $23.54^{\circ}C$. It means Daegu-Metropolitan-City has the serious heat-island effect. the results of landuse pattern analysis, in case of fifth and forth grade, city area was occupied over 90% with residential, commercial and industrial areas, but in case of third grade, openspace was occupied over 70%. The results of developing density analysis, the temperature had high correlation with building ratio, road ratio, vegetation ratio and etc. To plan for the decrease of heat island effect needed the extension of green space, decrease of paving, but there was a limit to get the objective method for grade classification because of lacking in the basic data, the research of criteria will be accomplished continuously.