• 산업경영시스템학회지
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• 제41권1호
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• pp.110-117
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• 2018

Machines and facilities are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. By the result of degeneration, non-conforming products and malfunction of machine occur. Therefore a periodic preventive resetting the process is necessary. This type of preventive action is called 'preventive maintenance policy.' Preventive maintenance presupposes that the preventive (resetting the process) cost is smaller than the cost of failure caused by the malfunction of machine. The process mean shift problem is a field of preventive maintenance. This field deals the interrelationship between the quality cost and the process resetting cost before machine breaks down. Quality cost is the sum of the non-conforming item cost and quality loss cost. Quality loss cost is due to the deviation between the quality characteristics from the target value. Under the process mean shift, the quality cost is increasing continuously whereas the process resetting cost is constant value. The objective function is total costs per unit wear, the decision variables are the wear limit (resetting period) and the initial process mean. Comparing the previous studies, we set the process variance as an increasing concave function and set the quality loss function as Cpm+ simultaneously. In the Cpm+, loss function has different cost coefficients according to the direction of the quality characteristics from target value. A numerical example is presented.

• Journal of the Korean Data and Information Science Society
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• 제17권2호
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• pp.421-436
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• 2006

Huang proposed a grey-based nearest neighbor approach to predict accurately missing attribute value in 2004. Our study proposes which way to decide the number of nearest neighbors using not only the deng's grey relational grade but also the wen's grey relational grade. Besides, our study uses not an arithmetic(unweighted) mean but a weighted one. Also, GRG is used by a weighted value when we impute missing values. There are four different methods - DU, DW, WU, WW. The performance of WW(Wen's GRG & weighted mean) method is the best of any other methods. It had been proven by Huang that his method was much better than mean imputation method and multiple imputation method. The performance of our study is far superior to that of Huang.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2006년도 PROCEEDINGS OF JOINT CONFERENCEOF KDISS AND KDAS
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• pp.55-62
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• 2006

Huang proposed a grey-based nearest neighbor approach to predict accurately missing attribute value in 2004. Our study proposes which way to decide the number of nearest neighbors using not only the dong's grey relational grade but also the wen's grey relational grade. Besides, our study uses not an arithmetic(unweighted) mean but a weighted one. Also, GRG is used by a weighted value when we impute a missing values. There are four different methods - DU, DW, WU, WW. The performance of WW(wen's GRG & weighted mean) method is the best of my other methods. It had been proven by Huang that his method was much better than mean imputation method and multiple imputation method. The performance of our study is far superior to that of Huang.

• 대한수의학회지
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• 제20권2호
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• pp.175-178
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• 1980

Normal values of serum electrolytes were determined for adult 36 females and 18 males, 1 to 6 years old, of Jindo dogs. The mean values, standard deviation and rangEs of sodium, potassium, chloride, calcium and inorganic phosphorus were studied and data analyzed to determine whether differences existed between the values of female and those of male dogs. The results obtained in this study were as follows: 1. The mean value of serum sodium was $143{\pm}1.5mEq/liter$, ranged from 138mEq/liter to 152 mEq/liter. The mean values for the females and males were $144{\pm}2.0mEq/liter$ and $142{\pm}1.7mEq/liter$, respectively. They showed that the female dogs had a tendency toward higher values than the male dogs, but no significant sex-related differences were observed. 2. The mean value of serum potassium was $4.6{\pm}0.2mEq/liter$, ranged frem 3.5mEq/liter to 6.0mEq/liter. The mean values for the females and males were $4.7{\pm}0.4mEq/liter$ and $4.5{\pm}0.3mEq/liter$. They showed that the female dogs had a tendency toward higher values than the male dogs, but sex differences were not found to be significant. 3. The mean value of serum chloride was $103{\pm}3.0mEq/liter$ ranged from 95mEq/liter to 117mEq/liter. The mean values for the females and males were $103{\pm}3.2mEq/liter$ and $103{\pm}3.3mEq/liter$, no sex differences showed. 4. The mean value of serum calcium was $5.2{\pm}0.1mEq/liter$ ranged from 4.7mEq/liter to 5.8mEq/liter. The mean values for the females and males were $5.4{\pm}0.1mEq/liter$ and $5.2{\pm}0.09mEq/liter$ respectively, no significant sexd iffere-nces were observed. 5. The mean value of serum inorganic phosphorus was $4.3{\pm}0.7mg/100ml$, ranged from 2.5mg/100ml to 5.8mg/100ml. The mean values for the females and males were $4.3{\pm}0.9mg/100ml$ and $4.1{\pm}0.8mg/100ml$, respectively, no sex differences showed.

• Journal of Trauma and Injury
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• 제34권1호
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• pp.13-20
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• 2021

Purpose: Nutritional therapy in the intensive care unit is an essential factor for patient progress. The purpose of this study was to compare resting energy expenditure (REE) calculated by prediction equations (PEs) to the REE measured by indirect calorimetry (IC) in trauma patients. Methods: Patients admitted to the trauma intensive care unit who received mechanical ventilation between January and December 2015 were enrolled. REE was measured by IC (CCM Express, MGC Diagnostics) and calculated by the following PEs: Harris-Benedict, Fleisch, Robertson and Reid, Ireton-Jones, and the maximum value (25 kcal/kg/day) of the European Society for Clinical Nutrition and Metabolism (ESPEN). All patients were ventilated at a fraction of inspired oxygen (FiO2) below 60%. Results: Of the 31 patients included in this study, 24 (77.4%) were men and seven (22.6%) were women. The mean age of the patients was 49.7±13.2 years, their mean weight was 68.1±9.6 kg, and their mean Injury Severity Score was 26.1±11.3. The mean respiratory quotient on IC was 0.93±0.19, and their mean FiO2 was 38.72%±6.97%. The mean REE measured by IC was 2,146±444.36 kcal/day, and the mean REE values calculated by the PEs were 1,509.39±205.34 kcal/day by the Harris and Benedict equation, 1,509.39±154.33 kcal/day by the Fleisch equation, and 1,443.39±159.61 kcal/day by the Robertson and Reid equation. The Ireton-Jones equation yielded a higher value (2,278.90±202.35 kcal/day), which was not significantly different from the value measured using IC (p=0.53). The ESPEN maximum value (1,704.03±449.36 kcal/day) was lower, but this difference was likewise not significant (p=0.127). Conclusions: The REE measured by IC was somewhat higher than that calculated using PEs. Further studies are needed to determine the proper nutritional support for trauma patients.

• 한국대기환경학회지
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• 제9권2호
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• pp.132-139
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• 1993

TCM has been used for many environmental impact assessments and many case studies in Korea. TCM was applied to urbvan areas and rolling terrains. But original TCM was developed for rural area, and this model could not reflect the characteristcs of these study sites. This paper analyzed the characteristics of TCM, and modified the algorithm of area source, and modified the vertical wind speed profile exponents and diffusion parameter to make it applicable in urban area. In the process of modification, an important error in area source calculation of original TCM program was found. So that was corrected as follows. $$ Before modification $QC = 0.79788456^*(0.5^*GRID)^**BA/(U(IA, IRUN)^*AA^*BA TCM09310$ After modification $QC = 0.79788456^*(500^*GRID)^**BA/(U(IA, IRUN)^*AA*BA) modified$ $$ Then original TCM and modified TCM-urban mode were compared, and it was found that predicted mean value by original TCM was 7 times higher than observed mean value. But mean value by modified TCM-urban mode was very similar to observed value.

• Journal of the Korean Statistical Society
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• 제33권3호
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• pp.323-337
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• 2004

This article coined a general class of estimators for various measures in normal population when some' a priori' or guessed value of standard deviation a is available in addition to sample information. The class of estimators is primarily defined for a function of standard deviation. An unbiased estimator and the minimum mean squared error estimator are worked out and the suggested class of estimators is compared with these classical estimators. Numerical computations in terms of percent relative efficiency and absolute relative bias established the merits of the proposed class of estimators especially for small samples. Simulation study confirms the excellence of the proposed class of estimators. The beauty of this article lies in estimation of various measures like standard deviation, variance, Fisher information, precision of sample mean, process capability index $C_{p}$, fourth moment about mean, mean deviation about mean etc. as particular cases of the proposed class of estimators.

• 대한산업공학회지
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• 제29권3호
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• pp.239-246
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• 2003

Individual items are produced continuously from an industrial process. Each item is checked to determine whether it satisfies a lower screening limit for the quality characteristic which is the weight of an expensive ingredient. If it does, it is sold at a regular price; if it does not, it is reprocessed or sold at a reduced price. The process mean may be adjusted to a higher value in order to reduce the proportion of the nonconforming items. Using a higher process mean, however, may result in a higher production cost. In this paper, the optimal process mean and lower screening limit are determined in situations where the probability that an item functions well is given by a logistic function of the quality characteristic. Profit models are constructed which involve four price/cost components; selling prices, cost from an accepted nonconforming item, and reprocessing and inspection costs. Methods of finding the optimal process mean and lower screening limit are presented and numerical examples are given.

• 대한수학회보
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• 제50권3호
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• pp.873-883
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• 2013

By using the analytic methods, the mean value of the general quadratic Gauss sums weighted by the first power mean of character sums over a short interval is investigated. Several sharp asymptotic formulae are obtained, which show that these sums enjoy good distributive properties. Moreover, interesting connections among them are established.

• 대한수학회지
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• 제47권6호
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• pp.1107-1122
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• 2010

In this paper, we shall use analytic methods to study the hybrid mean value involving the mixed two-term exponential sums C(m, n, r, $\chi$; q), and give several sharp asymptotic formulae.