• Communications for Statistical Applications and Methods
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• v.22 no.3
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• pp.255-264
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• 2015

This paper addressed the problem of estimation of finite population mean in double sampling for stratification. This paper proposed a generalized ratio-cum-product type estimator of population mean. The bias and mean square error of the proposed estimator has been obtained upto the first degree of approximation. A particular member of the proposed generalized estimator was identified and studied from a comparison point of view. It is observed that the identified particular estimator is more efficient than usual unbiased estimator and Ige and Tripathi (1987) estimators. An empirical study was conducted in support of the theoretical findings.

• Kyungpook Mathematical Journal
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• v.49 no.1
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• pp.167-181
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• 2009

Based on Ricatti equation $XA^{-1}X=B$ for two (positive invertible) operators A and B which has the geometric mean $A{\sharp}B$ as its solution, we consider a cubic equation $X(A{\sharp}B)^{-1}X(A{\sharp}B)^{-1}X=C$ for A, B and C. The solution X = $(A{\sharp}B){\sharp}_{\frac{1}{3}}C$ is a candidate of the geometric mean of the three operators. However, this solution is not invariant under permutation unlike the geometric mean of two operators. To supply the lack of the property, we adopt a limiting process due to Ando-Li-Mathias. We define reasonable geometric means of k operators for all integers $k{\geq}2$ by induction. For three positive operators, in particular, we define the weighted geometric mean as an extension of that of two operators.

• 한국해양학회지
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• v.10 no.2
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• pp.67-75
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• 1975

Tidal Flushing at the entrance channels of tidal bay or estuary in the central western coast of Korea; Gum River Estuary, Garorim Bay, Asan Bay, and Yeomha Estuary were studied with the recent data of current surveys measured by curret meter at three or five anchored stations along the section for one or two tidal periods at mean spring tide. Equilibrium relationship between tidal prism at mean spring tide and minimum flow area below the mean sea level of the channel in alluvial material was found as of O'Brien's (1931, 1969) study. Bed load transport in the tidal channel is balanced with the tidal flushing ability having a mean velocity of about 0.75m/sec or maximum velocity of about 1.25m/sec for a half tidal cycle over the section at mean spring tide which fairly agree with Brunn's study(1955, 1957). flushing actions for different hydraulic depth( mean depth) and bed material size in the channel were reviewed and found that it depend to a minor extent on the factors.

• Kyungpook Mathematical Journal
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• v.54 no.4
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• pp.521-529
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• 2014

In this paper we derive some optimal convex combination bounds related to arithmetic mean. We find the greatest values ${\alpha}_1$ and ${\alpha}_2$ and the least values ${\beta}_1$ and ${\beta}_2$ such that the double inequalities $${\alpha}_1T(a,b)+(1-{\alpha}_1)H(a,b)<A(a,b)<{\beta}_1T(a,b)+(1-{\beta}_1)H(a,b)$$ and $${\alpha}_2T(a,b)+(1-{\alpha}_2)G(a,b)<A(a,b)<{\beta}_2T(a,b)+(1-{\beta}_2)G(a,b)$$ holds for all a,b > 0 with $a{\neq}b$. Here T(a,b), H(a,b), A(a,b) and G(a,b) denote the second Seiffert, harmonic, arithmetic and geometric means of two positive numbers a and b, respectively.

• Journal of the Korean Statistical Society
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• v.24 no.2
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• pp.563-568
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• 1995

It is well-known that the sample mean and the sample variance are jointly sufficient under normality assumption. In this paper a proof of the joint sufficiency is given without using the factorization criterion. It is related to a finite Sanov-type conditional theorem, i.e., the conditional probability density of $Y_1$ given sample mean $\mu$ and sample variance $\sigma^2$, where $Y_1, Y_2, \cdots, Y_n$ are independently and identically distributed (i.i.d.) normal random variables with mean m and variance $\delta^2$, equals that of $Y_1$ given sample mean $\mu$ and sample variance $\sigma^2$, where $Y_1, Y_2, \cdots, Y_n$ are i.i.d. normal random variables with mean $\mu$ and variance $\sigma^2$.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.4
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• pp.83-89
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• 2004

In this paper MIP(mean inventory period) Model and OMMIP decision flow have been developed. MIP model can calculate mean inventory period which is subject to the order quantity alternative plan. OMMIP decision flow leads how can decide the most minimized order quantity in mean inventory period among various order quantity alternatives. This paper also suggests how to select the order quantity with minimum inventory period as optimal order quantity by means of comparison each mean inventory period with other mean inventory period, after simulating EOQ and order quantity of OMMIP calculated in MIP model.

• Journal of Korean Neurosurgical Society
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• v.30 no.2
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• pp.201-206
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• 2001

Objective : The purpose of this study was to assess the complications, duration of admission, cost effectiveness, radiologic stabilization of the anterior cervical bone fusion in the treatment of cervical disc disease with and without plating. Materials and Methods : Fifty-two surgically treated patients for cervical disc disease were reviewed. Group I consisted of consecutive treated patients with iliac auto-bone graft without instrumentation after anterior cervical discectomy. Group II consisted of consecutive treated patients with iliac autologous-bone graft with CASPER cervical plate fixations. Radiologic fusion was decided when loss of end plate boundary between graft bone and vertebral body and immobile, maintenance of the disc space were evident on simple dynamic plain films. The patients were discharged after the stabilization of cervical motion by films was of tained. These groups were analysed multiple variably with Mann-Whitney U-test. Results : Group I consisted of 18 patients, group II consisted of 34 patients. Mean age was $49.0{\pm}8.1years$, mean duration of admission was $17.27{\pm}10.51days$, mean costs for treatment was $1,970,000{\pm}475,000won$. In group I, mean age was 47.7(34-60) years, 16 patients had undergo on one-level operation, 2-patients had undergo on two-level operation, mean duration of admission was $28.7{\pm}10.4days$, mean costs for treatment was $2,194,473{\pm}561,639won$. The periods of stabilization was $6.6{\pm}3.36weeks$ on radiologic study. Mean periods of out patient follow up was 16.8(6-64) weeks after discharge. Mean period of radiologic follow up was 17.3(4-6) weeks after surgical operation. In group II, mean age was 49.7(37-62) years and 18 patients one-level operation, 14- patients had undergo on two-level operation and 2-patients three-level operation. Mean duration of admission was $11.24{\pm}3.29days$, mean costs for treatment was $1,850,823{\pm}389,372won$. The periods of stabilization was $5.88{\pm}7.07weeks$ on radiologic study. Mean period of out patients follow up was 16.7(4-60) weeks after discharge. Mean period of radiologic follow up was 12.4(3-52) weeks after surgical operation. The duration of admission showed statistical significance in Group II but other items showed no significant difference between two groups. Conclusions : The more economic, early life return and effective method of cervical disc disease in our series were evident in patients who had undergone, iliac bone graft and plate fixations after anterior discectomy.

• Honam Mathematical Journal
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• v.38 no.3
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• pp.593-611
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• 2016

This paper is concerned with the classifications of quadric surfaces of first and second kinds in Euclidean 3-space satisfying the Jacobi condition with respect to their curvatures, the Gaussian curvature K, the mean curvature H, second mean curvature $H_{II}$ and second Gaussian curvature $K_{II}$. Also, we study the zero and non-zero constant curvatures of these surfaces. Furthermore, we investigated the (A, B)-Weingarten, (A, B)-linear Weingarten as well as some special ($C^2$, K) and $(C^2,\;K{\sqrt{K}})$-nonlinear Weingarten quadric surfaces in $E^3$, where $A{\neq}B$, A, $B{\in}{K,H,H_{II},K_{II}}$ and $C{\in}{H,H_{II},K_{II}}$. Finally, some important new lemmas are presented.

• Journal of Preventive Medicine and Public Health
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• v.11 no.1
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• pp.98-109
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• 1978

The study was carried out for 101 establishments in Kyong-In areas to evaluate the industrial health management status utilizing the scoring method by Webb's model during the period from 1 September to October 30, 1977. To compare the results, reevaluation was made with the 45 questions' model prepared by 6 Korean professionals who were specialized in industrial health fields. The results were as follows: 1. The mean rate of affirmative answers for 101 establishments was 51.6%. The mean weighted score rate of affirmative answers was 52.3%. 2. The mean rate of affirmative answers on components of the philosophy and facility resource for 101 establishments was higher than that of average rate. The mean rate of affirmative answers on components of the health evaluation and health management among the health service program was lower than that of average rate. 3. The mean rate of affirmative answers on components was highter among the establishments with more than 500 employees. The mean rate of affirmative answers of chemical establishment was lower than that of others. 4. The mean rate of affirmative answers on 45 questions' model for 101 establishments were 67.1%. The mean weighted score rate of affirmative answers was 70.0%. 5. In case of 45 questions' model, the mean rate of affirmative answers on components of philosophy and treatment was higher than that of average rate and the mean rate of affirmative answers on components of the facility resource and the health evaluation was lower than that of average rate. 6. The mean rate of affirmative answers of the 45 Questions' model was higher than that of Webb's model in size and class of 101 establishments. Author concluded that Webb's model must be suitable for evaluating higher conditions of occupational health management than is presently used in Korean establishments. According to the results, however, there were no significant differences between Webb's model and the 45 questions' model. So it could be used to evaluate Occupational Health Program. For this objective, in Korean occupational situations, further study also must be made comprehensively thereafter.

• Journal of applied mathematics & informatics
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• v.33 no.5_6
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• pp.723-738
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• 2015

In this paper, the prescribed mean curvature Rayleigh p-Laplacian equation with a deviating argument