• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.61-67
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• 2020

The fourth industrial revolution encourages manufacturing industry to pursue a new paradigm shift to meet customers' diverse demands by managing the production process efficiently. However, it is not easy to manage efficiently a variety of tasks of all the processes including materials management, production management, process control, sales management, and inventory management. Especially, to set up an efficient production schedule and maintain appropriate inventory is crucial for tailored response to customers' needs. This paper deals with the optimized inventory policy in a steel company that produces granule products under supply contracts of three targeted on-time delivery rates. For efficient inventory management, products are classified into three groups A, B and C, and three differentiated production cycles and safety factors are assumed for the targeted on-time delivery rates of the groups. To derive the optimized inventory policy, we experimented eight cases of combined safety stock and data analysis methods in terms of key performance metrics such as mean inventory level and sold-out rate. Through simulation experiments based on real data we find that the proposed optimized inventory policy reduces inventory level by about 9%, and increases surplus production capacity rate, which is usually used for the production of products in Group C, from 43.4% to 46.3%, compared with the existing inventory policy.

• Journal of Families and Better Life
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• v.21 no.1
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• pp.13-24
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• 2003

The purpose of this article Is to review the problems in using Hazan & Shaver,s adult attachment inventory as spousal attachment inventory. In summary, Hazan & Shaver's forced-choice inventory is required to caution in using for spouse attachment inventory because of the disproportionally higher secure-attachment type ratio(72% - 89%). It was previous reseaches that used multi-item Likert inventory instead of Hazan & shaver's forced-choice inventory for result analysis because of disproportionally higher secure-attachment type ratio. Although Hazan & shaver's forced-choice inventory was mostly used for young unmarried adults, Using Hazan & shaver's forced-choice inventory as spouse attachment inventory for married adults seem to be inappropriately. Hazan & Shaver's multi-item Likert inventory has the problem of poor reliability in insecure-avoidence factor especially. Hazan & Shaver's one item Likert inventory has the problem of social desirability.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.69-78
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• 2010

Multi-criteria ABC inventory classification is one of the most widely employed techniques for efficient inventory control, and it considers more than one criterion for categorizing inventory items into groups of different importance. Recently, Ramanathan (2006) proposed a weighted linear optimization (WLO) model for the problem of multi-criteria ABC inventory classification. The WLO model generates a set of criteria weights for each item and assigns a normalized score to each item for ABC analysis. Although the WLO model is considered to have many advantages, it has a limitation that many items can share the same optimal efficiency score. This limitation can hinder a precise classification of inventory items. To overcome this deficiency, we propose a context-dependent DEA based method for multi-criteria ABC inventory classification problems. In the proposed model, items are first stratified into several efficiency levels, and then the relative attractiveness of each item is measured with respect to less efficient ones. Based on this attractiveness measure, items can be further discriminated in terms of their importance. By a comparative study between the proposed model and the WLO model, we argue that the proposed model can provide a more reasonable and accurate classification of inventory items.

• Journal of the Korea Safety Management & Science
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• v.15 no.1
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• pp.217-229
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• 2013

As customers' demands for diversified small-quantity products have been increased, there have been great efforts for a firm to respond to customers' demands flexibly and minimize the cost of inventory at the same time. To achieve that goal, in SCM perspective, many firms have tried to control the inventory efficiently. We present an mathematical model to determine the near optimal (s, S) policy of the supply chain, composed of multi suppliers, a warehouse and multi retailers. (s, S) policy is to order the quantity up to target inventory level when inventory level falls below the reorder point. But it is difficult to analyze inventory level because it is varied with stochastic demand of customers. To reflect stochastic demand of customers in our model, we do the analyses in the following order. First, the analysis of inventory in retailers is done at the mathematical model that we present. Then, the analysis of demand pattern in a warehouse is performed as the inventory of a warehouse is much effected by retailers' order. After that, the analysis of inventory in a warehouse is followed. Finally, the integrated mathematical model is presented. It is not easy to get the solution of the mathematical model, because it includes many stochastic factors. Thus, we get the solutions after the stochastic demand is approximated, then they are verified by the simulations.

• IE interfaces
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• v.25 no.2
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• pp.241-254
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• 2012

This paper studies the relationship between SCM(Supply Chain Management) metrics and corporate value (Tobin's Q) for manufacturing and wholesale/retail firms in Korea. Specifically, the multiple regression analysis is used to investigate the relationships 1) between inventory level, inventory turns, and days of inventory and Tobin's Q and 2) between cash-to-cash (C2C) cycle time including its components such as days of inventory, days sales outstanding, and days payable outstanding and Tobin's Q. The results indicate that there exist statistically significant negative relationships between inventory levels and days of inventory (DOI) and Tobin's Q. Also, we found that there exist commonly known negative correlations between days of raw materials inventory and days of work in process (WIP) inventory and Tobin's Q. For the C2C cycle time, we found that there -exists a statistically significant negative relationship between the C2C cycle time and Tobin's Q. Also, we found that there exist commonly known correlations between the two components of C2C cycle time and Tobin's Q such as the negative for DOI and days sales outstanding. This study clearly shows the negative relationship in general between inventory levels and corporate value and between C2C time and corporate value, and this kind of result has not been found by previous studies in Korea.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.58
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• pp.101-111
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• 2000

This study uses financial statements on several hundred companies listed in the Korea Stock Market to analyze trends in inventory turnover ratios and examine the effect of inventory performance on the profitability of the companies. Statistical analyses are done to determine if there have been significant changes in inventory turnover ratios and how turnover ratio pattern varied by factors such as industry, size of the firm, and the effectiveness of previous inventory management. Inventory turnover ratios decreased for four consecutive years and were found to vary by industry. Also it is proved that there was statistically significant relationship between the size of the firm and the average level of inventory as a fraction of sales. Regression analysis is done to investigate the relationship between the inventory management performance and profitability of companies and it is found that improvement in inventory level affected profitability of the companies.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.13 no.21
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• pp.61-72
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• 1990

In the past, a fundamental technique in inventory control system was to rank the items of a inventory from a distribution by value to draw an ABC curve. Unfortunately the use of ABC categorization technique has created problems and introduced some gross errors into the inventory control system. First, the author considers the possible applications of the technique in the real world and then attempts to discuss ABC fallacies through the literatures. Finally, an inventory categorization algorithm by the principal component analysis is derived and a numerical example is also presented to illustrate the algorithm.

• Journal of Oriental Neuropsychiatry
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• v.27 no.3
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• pp.131-146
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• 2016

Objectives: This study was performed to determine the correlation between Instrument on Pattern Identification for Depression and Psychological tests by Pearson Correlation Coefficient and Regression analysis.Methods: Two assessors carried out the evaluation using the instrument on pattern identification for depression. They also performed the following psychological tests: Beck Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI), State-Trait Anger Expression Inventory (STAXI), the Temperament and Character Inventory (TCI), Insomnia Severity Index (ISI_Total), Self-disclosure Inventory, subjective well-being Inventory, Health perception Inventory, and Personality Assessment Inventory (PAI). A total of 167 participants who got HAM-D score over 12 were targeted for the evaluation. Our research team carried out Pearson correlation coefficient analyses and regression analysis between pattern identification for depression and Psychological tests. We listed the results by descending order and interpreted the results.Results: Pearson correlation analysis revealed the following results: 1) Stagnation of Liver Gi was associated with BDI (0.60) and STAI (0.55); 2) Dual Deficiency of the Heart and Spleen was associated with BDI (0.60), ISI_Total (0.52), and STAI (0.42); 3) Relieving stagnation of Phlegm-Gi was associated with BDI (0.65), STAI (0.54), and Subjective well-being inventory (−0.52); 4) Gi-deficiency Mingled with sputum was associated with BDI (0.50), ISI_Total (0.40), and STAI (0.395); 5) Stagnant Gi transforming into fire was associated with BDI (0.56), STAI_TR (0.51), and Health perception Inventory (−0.458); 6) Yin-Deficiency with Effulgent Fire was associated with BDI (0.55), ISI_total (0.54), and STAI (0.41).Conclusions: Through correlation analysis between Instrument on Pattern Identification for Depression and Psychological tests, we could suggest a System for Oriental Medical Diagnosis for Depression.

• Proceedings of the Safety Management and Science Conference
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• 2010.04a
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• pp.189-197
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• 2010

Recently, industrial business environments have rapidly changed and face severe competitive challenges. The effective inventory system enables to product and deliver the products quickly for meeting due date of customer's order in this environment. This study have developed a web-based inventory system framework using RFID for a plastic injection molding industry. The system analysis inventory problem issues such as inventory planning, warehouse assignment. In this study, web-based inventory system using Java language is proposed and implemented. As the result of implementation of the system, we expected that it manages to inventory planning continually and systematically.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.742-749
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• 2002

This paper deals with a continuous-review two-echelon inventory model with one-for-one replenishment and Poisson demand where transshipments among retailers are allowed. Two classes of inventory systems are considered by the number of distribution centers(DCs) which provide each retailor with inventory items. 1:N class inventory system and M:N class inventory system respectively. Two-phase model is constructed to find out the optimal inventory positions which minimize supply chain costs. Approximations for customer service levels of the system are evaluated in the first phase, and the optimal inventory positions are found subject to the constraints for service level in the second phase. Simulation tests are performed to assure the effectiveness of the proposed model. The effect of transshipment is evaluated.