• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.253-259
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• 2017

Recent development in science and technology has modernized the weapon system of ROKN (Republic Of Korea Navy). Although the cost of purchasing, operating and maintaining the cutting-edge weapon systems has been increased significantly, the national defense expenditure is under a tight budget constraint. In order to maintain the availability of ships with low cost, we need accurate demand forecasts for spare parts. We attempted to find consumption pattern using data mining techniques. First we gathered a large amount of component consumption data through the DELIIS (Defense Logistics Intergrated Information System). Through data collection, we obtained 42 variables such as annual consumption quantity, ASL selection quantity, order-relase ratio. The objective variable is the quantity of spare parts purchased in f-year and MSE (Mean squared error) is used as the predictive power measure. To construct an optimal demand forecasting model, regression tree model, randomforest model, neural network model, and linear regression model were used as data mining techniques. The open software R was used for model construction. The results show that randomforest model is the best value of MSE. The important variables utilized in all models are consumption quantity, ASL selection quantity and order-release rate. The data related to the demand forecast of spare parts in the DELIIS was collected and the demand for the spare parts was estimated by using the data mining technique. Our approach shows improved performance in demand forecasting with higher accuracy then previous work. Also data mining can be used to identify variables that are related to demand forecasting.

• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.65-75
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• 2016

Unused spare parts of military equipments which have been kept in the warehouse for a long term have been recognized as wasting of defense budget which also decreased people's confidence in the field of national defence. It is known that overstock is caused by information distortion and bullwhip effect from downstream to upstream in the logistic support as is like business cases. After upgrading the logistic information system, it is possible for Army Logistics Command(ALC) to know demand information of end-user which is the key factor to reduce bullwhip effect. However, inventory is still overstocked and stock-out at the same time. Previous studies have not accounted for these phenomenons and have mainly focused on forecasting inventory level instead of budgetary process(budget period, PROLT, ASL/N-ASL). Thus, this study focuses on the information distortion, overstock and stock-out which caused by budgetary process in the logistic support with system dynamics and simulation.

• The Korean Journal of Quaternary Research
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• v.19 no.1
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• pp.1-17
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• 2005

This study aims to study the distribution and formation age of Quaternary deposits in the downstream of Yeongsan Estuarine River, encompassing Muan, Illo and Donggang counties. For this purpose the authors examine several borehole data, and step trench survey for excellent profiles was studied in connection with grain size population and magnetic susceptibility. As a result, it is interpreted that the coastal plain of the Yeongsan River was formed by sea level rise after Last Glacial Maximum(LGM). The fore edge/escarpment of coastal terraces distributed 7-10 m asl is assumed to be formed during the last glacial period, while the coastal terraces distributed above 7-10m asl formed during MIS 5a. In addition, the fore edge/escarpment of coastal terraces distributed above 15 m asl is presumed to be have been formed during the stadial of last interglacial period, while the formation age of coastal terraces distributed above 15m(asl) is assumed to be MIS 5e. This formation age can be estimated by the coastal terrace ages of the southeastern coast of Korean Peninsula. The characteristics of Quaternary deposits linked to paleolithic culture will eventually lead to the reconstruction of ecosystem environment of paleolithic peoples.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.1
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• pp.91-104
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• 2023

The records system is believed to have started in Italy in the 14th century in line with trade developments in Europe. In 1491, Luca Pacioli, a mathematician, and an Italian Franciscan monk wrote the first book that described double-entry accounting processes. In many countries, including Korea, the government accounting standards used single-entry bookkeeping rather than double-entry bookkeeping that can be aggregated by account subject. The cash-based and single-entry bookkeeping used by the government in the past had limitations in providing clear information on financial status and establishing a performance-oriented financial management system. Accordingly, the National Accounting Act (promulgated in October 2007) stipulated the introduction of double-entry bookkeeping and accrual accounting systems in the government sector from January 1, 2009. Furthermore, the Korean government has also introduced International Financial Reporting Standards (IFRS), and the System of National Accounts (SNA). Since 2014, Korea owned five national accounts. In Korea, valuation began with the 1968 National Wealth Statistics Survey. The academic origins of the valuation of national wealth statistics which had been investigated by due diligence every 10 years since 1968 are based on the 'Engineering Valuation' of professor Marston in the Department of Industrial Engineering at Iowa State University in the 1930s. This field has spread to economics, etc. In economics, it became the basis of capital stock estimation for positive economics such as econometrics. The valuation by the National Wealth Statistics Survey contributed greatly to converting the book value of accounting data into vintage data. And in 2000 National Statistical Office collected actual disposal data for the 1-digit asset class and obtained the ASL(average service life) by Iowa curve. Then, with the data on fixed capital formation centered on the National B/S Team of the Bank of Korea, the national wealth statistics were prepared by the Permanent Inventory Method(PIM). The asset classification was also classified into 59 types, including 2 types of residential buildings, 4 types of non-residential buildings, 14 types of structures, 9 types of transportation equipment, 28 types of machinery, and 2 types of intangible fixed assets. Tables of useful lives of tangible fixed assets published by the Korea Appraisal Board in 1999 and 2013 were made by the Iowa curve method. In Korea, the Iowa curve method has been adopted as a method of ASL estimation. There are three types of the Iowa curve method. The retirement rate method of the three types is the best because it is based on the collection and compilation of the data of all properties in service during a period of recent years, both properties retired and that are still in service. We hope the retirement rate method instead of the individual unit method is used in the estimation of ASL. Recently Korean government's accounting system has been developed. When revenue expenditure and capital expenditure were mixed in the past single-entry bookkeeping we would like to suggest that BOK and National Statistical Office have accumulated knowledge of a rational difference between revenue expenditure and capital expenditure. In particular, it is important when it is estimated capital stock by PIM. Korea also needs an empirical study on economic depreciation like Hulten & Wykoff Catalog A of the US BEA.

• Food Science and Preservation
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• v.30 no.2
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• pp.347-357
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• 2023

The succulent plant Aeonium sedifolium leaves contain several compounds that are of interest for their cosmetic uses on the skin. This study measured the inhibitory effects of enzyme production and antioxidant, astringent effects and skin wrinkles using Aeonium sedifolium leaves (ASL). The total phenolics compounds (TPC) content of ASL under optimal extraction conditions was 34.49 mg/g for hot water extract (ASLW) and 61.64 mg/g for 50% ethanol extract (ASLE). The ASLW and ASLE extracts were freeze-dried, powdered, and used as solids. TPC content, 2,2-diphenyl-1-picrylhydrazy (DPPH) radical scavenging activity, and 2,2'-azinobis (3-ethylben-zothiazoline 6-sulfonate) (ABTS) radical inhibition of the ASL phenolics were tested. The DPPH radical scavenging activities of ASLW and ASLE were tested at a TPC of 100 ㎍/mL. ABTS radical inhibition showed antioxidant activity of 100.00% in ASLW and ASLE, and the antioxidant protection factor of ASLW and ASLE was 1.07 and 1.22, respectively. The thiobarbituric acid-reactive substance (TBARS) inhibitory activity of ASLW and ASLE was 77.00%. The elastase inhibitory activity of ASLE was 69.03%, and collagenase inhibition activity for ASLW and ASLE was 29.82% and 54.76%, respectively. The astringent effect of ASLE was 89.82% at a TPC of 200 ㎍/mL. Thus, we concluded that ASL has the potential as a functional cosmetic ingredient with anti-aging effects on the skin.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.3
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• pp.232-238
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• 2004

The brake system of a high-speed train has a crucial role for the safety of human mass transportation. However, it is hard to acquire design parameters of the brake system in the design step of the new high-speed train. In this paper, we build a HILS (Hardware In-the- Loop Simulation) system for the brake system of the Korea High-Speed Train (KHST) that is supposed to run up to 350 km/h, and analyze the characteristics of the brake system of the KHST (composed of 7 cars) via real-time simulations. In the HILS system that is built using a DSP board of dSPACE, the dynamics of the 7 car bodies and several bogies and characteristics of springs and dampers of connection devices between cars are considered separately. Simulation results show that the designed brake system of the KHST is valid and satisfies design specifications.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.514.3-515
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• 1986

λP$_{L}$ promoter와 Infiuenza virus의 NS1 Structural gene이 있는 pASl EH801 plasmid를 E. coli host N5' 과 AR120에 각각 transformation하여 온도와 nalidixic acid로 각각 induction 하여 보았다 N5151의 경우, O.D.600 1.2에서 42$^{\circ}C$로 induction하였을 때 maximum productivity를 보였으며 AR120의 경우는 O. D. 600 1.2, 37$^{\circ}C$, 40$\mu\textrm{g}$ nalidixic acid/$m\ell$ induction 하였을 때 maximum yield를 보여주었다. 이때 pH, DO, temperature, $O_2$%, $CO_2$%를 A/D converter통해 computer에 연결시켜 data acquision을 한 결과, 접종 후 ON-line induction이 가능함을 알 수 있었다.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.169-169
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• 2001

Purpose： To assess the clinical usefulness of Transfer Insensitive Labeling Technique (TILT) in t evaluation of ischemic cerebrovascular disease. Method： Arterial spin labeling (ASL) is a method of perfusion weighted imaging usin endogenous water as a tracer. To avoid MT-related artifacts, which is common in usual A technique, a transfer insensitive labeling technique (TILT) was used, which globall manipulate macromolecular spins in the same way by both labeling and reference preparatio while free water is labeled in one case and left unchanged in the other. Philips Interal 1.5 T system was used. 40cm FOV and 32 repeated measurements were done because of the wea perfusion signal. 5 slices of supratentorial brain were obtained in 5 patients ｛MCA infar (n=3), moyamoya disease (n=2)｝. We simultaneously obtained contrast enhanced T2＊-weighted perfusion MRI and correlate to TILT images.

• Journal of applied mathematics & informatics
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• v.35 no.3_4
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• pp.323-330
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• 2017

Recently Samet, Vetro and Vetro introduced the notion of ${\alpha}$-${\Psi}$-contractive type mappings and initiated some fixed point theorems in complete metric spaces. The notion of ${\alpha}_*$ - ${\Psi}$-contractive multifunctions and initiated some fixed point results by Hasanzade Asl et. al. [8]. In this paper, we introduced the notion of ${\alpha}_*$ - ${\Psi}$-contractive multifunctions in a fuzzy metric space and gave fixed point results for these multifunctions in complete fuzzy metric spaces. We also obtain a fixed point results for self-maps in complete fuzzy metric spaces satisfying contractive condition.

• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.115-123
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• 2004

A recursive tree is constructed by starting with a root node and repeatedly adjoining new nodes to one node of the tree already constructed. Such a tree can represent, for example, the heirarchy of a workforce of a company that grows via recruiting. At times of economic depression, the company may decide to layoff participants, and in some cases it is a fair policy to relieve the last senior worker (most recent entry in the tree). If we remove an edge from such a tree then it falls into two subtrees one of which contains the most recent entry. If we continue to remove edges from the successively smaller subtrees that contain the most recent entry, we eventually isolate the most recent entry. We consider how many randomly selected edges must be removed in average before isolating the most recent entry by this procedure.