• Industrial Engineering and Management Systems
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• v.14 no.1
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• pp.1-10
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• 2015

In this paper, we consider multi-item inventory management. When managing a multi-item inventory, we coordinate replenishment orders of items supplied by the same supplier. The associated problem is called the joint replenishment problem (JRP). One often-used approach to the JRP is to apply a can-order policy. Under a can-order policy, some items are re-ordered when their inventory level drops to or below their re-order level, and any other item with an inventory level at or below its can-order level can be included in this order. In the present paper, we propose a method for finding the optimal parameter of a can-order policy, the can-order level, for each item in a lost-sales model. The main objectives in our model are minimizing the number of ordering, inventory, and shortage (i.e., lost-sales) respectively, compared with the conventional JRP, in which the objective is to minimize total cost. In order to solve this multi-objective optimization problem, we apply a genetic algorithm. In a numerical experiment using actual shipment data, we simulate the proposed model and compare the results with those of other methods.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.768-772
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• 2008

Today's microprocessor normally includes several processing cores to reduce the energy consumption without losing performance. In this paper, data transfer ordering mechanism can be efficiently used for cache coherence solution in unidirectional ring interconnect. RING-DATA ORDER combines the simplicity of GREEDY-ORDER and the performance of RING-ORDER. RING-DATA ORDER can be easily applicable to multicore processor with unidirectional ring interconnect.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.21 no.1
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• pp.1-16
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• 2017

The Allen-Cahn equation is solved numerically by operator splitting Fourier spectral methods. The basic idea of the operator splitting method is to decompose the original problem into sub-equations and compose the approximate solution of the original equation using the solutions of the subproblems. The purpose of this paper is to characterize higher order operator splitting schemes and propose several higher order methods. Unlike the first and the second order methods, each of the heat and the free-energy evolution operators has at least one backward evaluation in higher order methods. We investigate the effect of negative time steps on a general form of third order schemes and suggest three third order methods for better stability and accuracy. Two fourth order methods are also presented. The traveling wave solution and a spinodal decomposition problem are used to demonstrate numerical properties and the order of convergence of the proposed methods.

• Wind and Structures
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• v.31 no.5
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• pp.473-482
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• 2020

The first-order method for estimating the extreme wind pressure on building envelopes with consideration of the directionality of wind speed and wind pressure is improved to enhance its computational efficiency. In this improved method, the result is obtained directly from the empirical distribution of a random selection of annual maximum wind pressure samples generated by a Monte Carlo method, rather than from the previously utilized extreme wind pressure probability distribution. A discussion of the relationship between the first- and full-order methods indicates that when extreme wind pressures in a non-typhoon climate with a high return period are estimated with consideration of directionality, using the relatively simple first-order method instead of the computationally intensive full-order method is reasonable. The validation of this reasonableness is equivalent to validating two assumptions to improve its computational efficiency: 1) The result obtained by the full-order method is conservative when the extreme wind pressure events among different sectors are independent. 2) The result obtained by the first-order method for a high return period is not significantly affected when the extreme wind speeds among the different sectors are assumed to be independent. These two assumptions are validated by examples in different regions and theoretical derivation.

• Journal of the Korean Data and Information Science Society
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• v.10 no.1
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• pp.243-250
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• 1999

We consider $Y=X{\lambda}Z,\;{\lambda}>0$, where X and Z are independent random variables, and Y is the length biased distribution or the equilibrium distribution of X. The purpose of this paper is to consider the distribution of X or Y when the distribution of Z is given and the distribution of Z when the distribution of X or Y is given, In particular, we obtain that the necessary and sufficient conditions for X to be $X^{2}({\upsilon})\;is\;Z{\sim}X^{2}(2)\;and\;for\;Z\;to\;be\;X^{2}(1)\;is\;X{\sim}IG({\mu},\;{\mu}^{2}/{\lambda})$, where $IG({\mu},\;{\mu}^{2}/{\lambda})$ is two-parameter inverse Gaussian distribution. Also we show that X is smaller than Y in the reverse Laplace transform ratio order if and only if $X_{e}$ is smaller than $Y_{e}$ in the Laplace transform ratio order. Finally, we can get the results that if X is smaller than Y in the Laplace transform ratio order, then $Y_{L}$ is smaller than $X_{L}$ in the Laplace transform order, and that if X is smaller than Y in the reverse Laplace transform ratio order, then $_{\mu}X_{L}$ is smaller than $_{\nu}Y_{L}$ in the Laplace transform order.

• IE interfaces
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• v.14 no.1
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• pp.9-19
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• 2001

Production planning and control system plays an important role in manufacturing companies because it determines all production capacity planning, material procurement planning, and production scheduling which are needed in the process of producing products. Many researches on production planning and control system have been conducted for many manufacturing companies for recent decade. But, a considerable research achievement has mainly been obtained on the forecast-driven production for a make-to-stock and an assemble-to-order. The reason is that there are some hardships such as difficulties of standardizing product information, the frequent changes of design and material, and the unexpected dynamic events that influence the production of customer's order in a make-to-order or an engineering-to-order environments. By these characteristics and their complexities, some studies for production planning and control system in a make-to-order environment are presented recently. In this paper, we present the framework of the hietachical production planning and control for a make-to-order environment with dynamic events. In order to illustrate the usefulness of the proposed framework for a hietachical production planning and control, the information system for a make-to-order production was implemented with the object of the company of producing electricity transformer.

• Journal of applied mathematics & informatics
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• v.39 no.1_2
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• pp.197-214
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• 2021

In this paper, we have studied dynamics of fractional order mathematical model of malaria transmission for two groups of human population say semi-immune and non-immune along with growing stages of mosquito vector. The present fractional order mathematical model is the extension of integer order mathematical model proposed by Ousmane Koutou et al. For this study, Atangana-Baleanu fractional order derivative in Caputo sense has been implemented. In the view of memory effect of fractional derivative, this model has been found more realistic than integer order model of malaria and helps to understand dynamical behaviour of malaria epidemic in depth. We have analysed the proposed model for two precisely defined set of parameters and initial value conditions. The uniqueness and existence of present model has been proved by Lipschitz conditions and fixed point theorem. Generalised Euler method is used to analyse numerical results. It is observed that this model is more dynamic as we have considered all classes of human population and mosquito vector to analyse the dynamics of malaria.

• International Journal of Advanced Culture Technology
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• v.9 no.2
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• pp.91-99
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• 2021

In Korea, some pharmaceutical companies and agricultural machine manufacturers associate the length of the credit period with the retailer's order size. This kind of commercial practice is based on the principle of economy of scale from the supplier's point of view and tends to make retailer's order size large enough to qualify a certain credit period break. Also, the credit period allowed by the supplier makes it possible to reduce the retail price expecting that the retailer can earn more profits by the stimulating the customer's demand. Since the retailer's order size is affected by the end customer's demand, it is reasonable to determine the retail price and the order size simultaneously. In this regard, this paper analyzes the retailer's problem who has to decide his sales price and order quantity from a supplier who offers different credit periods depending on his order size. And we show that the retailer's order size large enough to qualify a certain credit period break. Also, it is assumed that the end customer's demand rate is represented by a linear decreasing function of the retail price.

• The Journal of Korean Medicine
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• v.17 no.2 s.32
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• pp.318-330
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• 1996

We had been investigated the effect of ear acupuncture in alcoholics, but in Kang won do province never we have been investigated. so then in Sangji university oriental hospital from Mar. 1. 1995 to Feb. 28. 1996. we clinically analized 102 alcoholics treated The results were summarized as follow: 1. In Age distribution, 40s were the top as 28.4% and next 30s, 50s, 60s 70s, below 3Os. In Sex distribution, these were 92 person in male, 10 person in female. 2. Marrige Status revealed in descending order ; married, single, divorced Sibling order distribution in descending order; eldest son, middle son, youngest son, only son 3. Distribution of education in descending order ; high school, middle school, primary school, collage and graduate school, illiterate 4. Distribution of occupation in descending order; farmer, labor, merchent, salaried and inoccupation, service 5. Distribution of religion in descending order ; none, buddism, protestantism, catholicism 6. Distribution of family history of alcoholism; yes(24.5%), no(69.6%) 7. Distribution of onset of drinking in descending order ; 20s, below 20s, 30s and 40s, 50s 8. Distribution of duration of drinking in descending order ; 20-29 years, 10-19 and below years, 40-49 years, 30-39 years 9. Distribution of the reason of drinking in descending order ; habbit, business and reduce of stress, no reason, syndrome of stop drinking 10. Distribution of frequency of drinking in descending order ; daily, four or five times a week, irregularly, once a week, two or three times a week 11. Distribution of amount of drinking in descending order ; two bottles, one bottle, three bottles, half, bottle above four bottles 12. Distribution of Chief Complaint of Alcohol in descending order ; no appetite and anorexia, diarrhrea insomnia, fatigue, vomitting, tremor, drinking water, hallucination, abdominal pain, constipation 13. Distribution of total MAST score in descending order ; 26-48 score, 13-18 score, 19-25 score, 8-12 score, 0-7 score 14. In the treatment effects according to MAST score, these were complete stop drinking 18.0%, improved 53.0%, unchanged 29.0%. 15. Distribution of liver function test and treatment effects in descending order ; ALAT, ASAT, GGTP, Trigliceride, Alk-phosphatase and Total bilirubin The treatment effects in ear acupuncture were 70.5% effective ones ; stop drinking 17.6%, improved 52.9%. 17. These were headache, nausea, vomitting sense, weakness in revealing symtoms after treatment, but no severe side effect. 18. Distribution of the times of onset in the change of taste in descending order; 3-5 times, below 2 times and above 6 times.

• Journal of Environmental Science International
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• v.20 no.11
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• pp.1465-1481
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• 2011

The accuracy of ozone sensitivity coefficients estimated with HDDM (High-order Decoupled Direct Method) can vary depending on the $NO_x$ (Nitrogen Oxides) and VOC (Volatile Organic Compound) conditions. In order to evaluate the applicability of HDDM over the Seoul Metropolitan Area (SMA) during a high ozone episode in 2007 June, we compare BFM (Brute Force Method) and HDDM in terms of the $1^{st}$-order ozone sensitivity coefficient to explain ozone change in response to changes in NOx and VOC emissions, and the $2^{nd}$-order ozone sensitivity coefficient to represent nonlinear response of ozone to the emission changes. BFM and HDDM estimate comparable ozone sensitivity coefficients, exhibiting similar spatial and temporal variations over the SMAduring the episode. NME (Normalized Mean Error) between BFM and HDDM for the episode average $1^{st}$- and $2^{nd}$-order ozone sensitivity coefficients to NOx and VOC emissions are less than 3% and 9%, respectively. For the daily comparison, NME for the $1^{st}$- and $2^{nd}$-order ozone sensitivity coefficients are less than 4% ($R^2$ > 0.96) and 15% ($R^2$ > 0.90), respectively. Under the emission conditions used in this study, two methods show negative episode average $1^{st}$-order ozone sensitivity coefficient to $NO_x$ emissions over the core SMA. The $2^{nd}$-order ozone sensitivity coefficient to $NO_x$ emissions leads ozone to respond muchnonlinear to the reduction in $NO_x$ emissions over Seoul. Nonlinear ozone response to reduction in VOC emissions is mitigated due to the $2^{nd}$-order ozone sensitivity coefficient which is much smaller than the $1^{st}$-order ozone sensitivity coefficient to the emissions in the magnitude.