• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.831-839
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• 2008

The steel industry is becoming more important around the world and the demand of steel is increasing. Korea is the 5th country of steel producing in the world and the attention in the steel industry is growing. The steel industry is one of the key industry in leading the economic growth in Korea. This study attempts to analyze by time-series the economic impacts of the steel industry using an inter-industry analysis Specifically, the study investigates production-inducing effect, value added inducing effect and employ-inducing effect of the steel industry based on demand-driven model and the study deals with supply shortage effect and sectoral price effect of the steel industry by using supply-driven model and Leontief price model.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.6
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• pp.15-20
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• 2008

Hydraulic analysis of water distribution system can be divided into demand-driven analysis and pressure-driven analysis. Demanddriven analysis can give unrealistic results to simulate hydraulic conditions under abnormal operating conditions such as sudden demand increase and pipe failure. In Korea, demand-driven analysis has been used to establish emergency water supply plan in many water projects, but it is necessary to use pressure-driven analysis for establishment of emergency water supply plan. In this study, WaterGEMS model that was developed for pressure-driven analysis is used to evaluation of emergency water supply plan of J city. As the results, it was able to draw up more efficient plan for water supply in small block, and established emergency water supply plan of J city was determined to be appropriate.

• Journal of the Korean Operations Research and Management Science Society
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• v.41 no.2
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• pp.1-16
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• 2016

Yield management, which originated from the U.S. service industry, uses pricing techniques and information systems to make demand management decisions. Demand uncertainty is an important factor in the area of demand management. A key strategy to reduce the effects of demand uncertainty is substitution. The most generally known type of substitution is inventory-driven substitution, in which consumers substitute an out-of-stock product by buying a similar or other type of product. Another type of substitution is the price-driven substitution, which occurs as a result of price changes. In this research, we consider two market segments that have unique perishable products. We develop yield management optimization models with stochastic demand based on the newsvendor model where inventory-driven and price-driven substitutions are allowed between products in the two market segments. The most significant contribution of this research is that it develops analytical procedures to determine optimal solutions and considers both types of substitution. We also provide detailed theoretical analysis and numerical examples.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.4
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• pp.169-181
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• 2011

The cooperation between universities and IT industry in producing IT manpower of quality is urgently called for to create the effective labor pool of supply and finally balance its supply and demand. Korean Government launched a program where industrial demand-driven curriculums are developed and applied to universities. This paper proposes a design technique of meta-modeling demand-driven curriculums and courses, based on the 3D software space and the software development process. This technique is proven to result in extensibility, flexibility and quality improvement in software design. Therefore, we expect that the proposed technique makes curriculums and courses possible to be continuously improved in many aspects.

• Industrial Engineering and Management Systems
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• v.14 no.2
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• pp.159-174
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• 2015

Remanufacturing used, end-of-life products is a complex problem involving multiple types of products that may share common parts. Recovery targets assigned by market demand and environmental legislation add more difficulty to the problem. Manufacturers now need to achieve specified take-back and recovery rates while fulfilling demands for remanufactured products. To assists in the demand- and legislation-driven remanufacturing of a family of products (i.e., multiple products that share common parts), this paper introduces a bi-objective mixed integer linear programming (MILP) model for optimizing remanufacturing. The model identifies optimal remanufacturing plans for a product family, whereby, the remanufacturer can achieve demand and recovery targets more profitably and in an environmentally-friendly manner. The model can also be used to quantify and justify the economic and environmental benefits of a product family from a remanufacturing perspective. A case study is presented for remanufacturing an alternatorfamily of products.

• Journal of Korea Water Resources Association
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• v.43 no.2
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• pp.201-210
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• 2010

In this study, new methodology to estimate the reliability of a water distribution system using HSPDA model is suggested. In general, the reliability of a water distribution system can be determined by estimating either the ratio of the required demand to the available demand or the ratio of the number of nodes with sufficient pressure head to the number of nodes with insufficient pressure head when the abnormal operating condition occurs. To perform this approach, hydraulic analysis under the abnormal operating condition is essential. However, if the Demand-Driven Analysis (DDA) which is dependant on the assumption that the required demand at a demand node is always satisfied regardless of actual nodal pressure head is used to estimate the reliability of a water distribution system, the reliability may be underestimated due to the defect of the DDA. Therefore, it is necessary to apply the Pressure-Driven Analysis (PDA) having a different assumption to the DDA's which is that available nodal demand is proportion to nodal pressure head. However, because previous study used a semi-PDA model and the PDA model which had limited applicability depending on the characteristics of a network, proper estimation of the reliability of a water distribution system was impossible. Thus, in this study, a new methodology is suggested by using HSPDA model which can overcome weak points of existing PDA model and Available Demand Fraction (ADF) index to estimate the reliability. The HSPDA can simulate the hydraulic condition of a water distribution system under abnormal operating condition and based on the hydraulic condition simulated, ADF index at each node is calculated to quantify the reliability of a water distribution system. The suggested model is applied to sample networks and the results are compared with those of existing method to demonstrate its applicability.

• Journal of the Korean Operations Research and Management Science Society
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• v.33 no.1
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• pp.1-17
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• 2008

Market segmentation is a key strategic factor in increasing the expected profits, especially in the practice of revenue management. A manufacturing firm should manage both manufacturing quantities and pricing decisions over its segmented markets to maximize the expected profits, setting different price for each different segment. Also, market segments should be kept separate in order to prevent demand leakages between different market segments. In fact, even though the markets for different products are firmly segmented, it is not easy to keep separate segmentation because many products might be substitutable by customer buying behavior. That is, customers respond to price changes by purchasing other market's products instead of purchasing the originally requested products, which causes demand substitution effect ; This kind of substitution is referred to as price-driven substitution. Therefore, decisions on optimal prices should take into account the differences in customers' valuation of the different products. We consider a deterministic model for deciding optimal prices in the presence of price-driven substitution, and we compare both symmetrical-and asymmetrical-type demand substitutions between two segmented markets. The objective of this study is to develop analytical and numerical models to examine the impact of price-driven substitution on the optimal price levels and the total expected profits.

• Environmental and Resource Economics Review
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• v.14 no.4
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• pp.839-866
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• 2005

This study addresses the effects on the economy of atomic sector's R&D by considering how much KAERI's R&D expenditures in 2000 affect on the production and value-added of each industry and the whole economy. This study answers to the question using competitive import input-output tables and both supply driven and demand driven IO models, which are frequently employed in evaluating economic impacts of R&D in both domestic and foreign academic areas.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.1-10
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• 2013

The value added network service industry has played and important role in the telecommunication service industry and in the economic development of Korea. This study uses input-output analysis to investigate the role of value added network service sector in the Korean national economy for the period 2000, 2005, 2009, focusing on four topics in its application: production inducing effects, value-added inducing effect, employment-inducing effects by demand-driven model and supply shortage effect by supply-driven model, inflation impacts by the Leontief price model, finally analysing inter-industry linkage effects. The results of this study are as follows: production inducing effects analysis 2000 0.5253won to 2009 1.31314won, value-added inducing effects 0.25112won to 0.5337won employment inducing effects from 0.09749 to 0.21025 people grew, the supply shortage effect from 1.29003 to 2.12048won, price impact of Leontief price model was increased from 0.0022% to 0.00258%. Finally, inter-industry linkage effects, appeared to have the characteristics of final demand raw industrial.

• Journal of Computational Design and Engineering
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• v.1 no.4
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• pp.233-242
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• 2014

A magnetically levitated vehicle (Maglev) system is under commercialization as a new transportation system in Korea. The Maglev is operated by an unmanned automatic control system. Therefore, the plan of train operation should be carefully established and validated in advance. In general, when making a train operation plan, statistically predicted traffic data is used. However, a traffic wave often occurs in real train service, and demand-driven simulation technology is required to review a train operation plan and service quality considering traffic waves. We propose a method and model to simulate Maglev operation considering continuous demand changes. For this purpose, we employed a discrete event model that is suitable for modeling the behavior of railway passenger transportation. We modeled the system hierarchically using discrete event system specification (DEVS) formalism. In addition, through implementation and an experiment using the DEVSim++ simulation environment, we tested the feasibility of the proposed model. Our experimental results also verified that our demand-driven simulation technology can be used for a priori review of train operation plans and strategies.