• 대한산업공학회지
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• 제24권4호
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• pp.475-483
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• 1998

Structural changes in an economy system bring about serious problems in establishing economic policies. The boom of middle-east export, the oil shock, and the recent dollar crisis in Korean economy are such examples. Hence, it is necessary to identify and estimate those structural changes. This study focuses on an output and price and analyzes structural changes in aggregate demand and supply. The aggregate demand and supply structures are described by conventional dynamic simultaneous equations model, where each structural change is represented by dummy variables and estimated by the proposed Bayesian method. By applying this model to Korean output and price, structural changes in the aggregate demand and supply are analyzed.

• Asia Marketing Journal
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• 제22권2호
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• pp.1-18
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• 2020

We estimate a choice-based aggregate demand model accounting for consumers' consideration sets, and study its implications on market structure. In contrast to past research, we model and estimate consumer demand using aggregate-level consumer browsing data in addition to aggregate-level choice data. The use of consumer browsing data allows us to study consumer demand in a realistic setting in which consumers choose from a subset of products. We calibrate the proposed model on both data sets, avoid biases in parameter estimates, and compute the price elasticity measures. As an empirical application, we estimate consumer demand in the camcorder category and study its implications on market structure. The proposed model predicts a limited consumer price response and offers a more discriminating competitive landscape from the one assuming universal consideration set.

• 산경연구논집
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• 제9권3호
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• pp.19-29
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• 2018

Purpose - This study empirically analyses the changes in unemployment rates to understand push factors of generating wage pressure and how it affects the aggregate demand in Korea and the United States. We use a structural macroeconomic model which is centered on the labor market and simultaneously explains the natural rate of unemployment and deviations. Research design, data and methodology - We attempt to empirically analyse the unemployment rates through two countries to analyse the economic effects of real wages and aggregate demand between 2000 and 2016. We introduce having estimated the whole model that the growth of unemployment into the part caused by each of these factors. Results - The results of this study show that in the long run, there is not only a natural level of employment but also a natural level of real demand are positively related. in the short run, demand can vary from bring about changes in employment by means of price or wage surprises. Conclusions - The pressure of demand in the labor market shows up strongly in both countries. The estimated labor-demand equation are consistent with this framework and generally have well defined real wage and demand effects.

• Asia Marketing Journal
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• 제21권3호
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• pp.47-64
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• 2019

We analyze and study competition in differentiated product market using public data source. Understanding competitive market structure is critical for firms to assess how their products compete against other firms in a given market. In this paper, we estimate consumer demand, extend clout and vulnerability framework, and study competition among multi-product manufacturers in differentiated product market. For our empirical analysis, we adopt choice-based aggregate demand model and estimate consumer demand while accounting for unobserved product characteristics. Once we estimate consumer demand, we compute full price elasticity matrix and investigate intra- and inter- manufacturer substitutions among consumers. This research offers a framework for marketers to analyze and understand market structures, leading them to informed decisions.

• 아태비즈니스연구
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• 제10권2호
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• pp.13-26
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• 2019

This paper aims to empirically examine the short-run and long-run aggregate demand for the US imports using quarterly economic data for the period 2000-2018 including aggregate imports, final expenditure components, gross fixed capital formation and relative price of imports. According to the results of both multivariate co-integration analysis and error correction model, the above variables are all cointegrated and significant differences are found to exist among the long-run partial elasticities of imports as regards different macro components of final expenditure. Partial elasticities with respect to government expenditure, gross fixed capital formation, exports and relative price of import are found to be positive while imports seems to respond negatively to changes in private consumption, implying that an increase in private consumption could result in a significant reduction in demand for imports in the long run. With regard to the relative import prices, the results appear to indicate a relatively insignificant influence on the aggregate imports in the US in the long run. However, an error correction model designed for predicting the short-term variability shows that only exports have an impact on the imports in the short run.

• Asian Journal of Business Environment
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• 제7권4호
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• pp.5-9
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• 2017

Purpose - Many countries rely on currency depreciation or debt-financed government spending to stimulate their economies. Currency depreciation tends to increase net exports and aggregate demand but reduce short-run aggregate supply due to higher import costs. Debt-financed government spending increases aggregate demand, but the crowding-out effect due to a higher real interest rate may reduce private spending and aggregate demand. Therefore, the net impact of currency depreciation or debt-financed government spending on equilibrium real GDP is unclear. Research design, data, and methodology - This paper examines potential impacts of real depreciation of the ringgit, more government debt as a percent of GDP and other relevant macroeconomic variables on aggregate output in Malaysia. Results - Applying the AD/AS model, this paper finds that aggregate output in Malaysia is positively associated with real appreciation during 2005.Q3-2010.Q3, real depreciation during 2010.Q4-2016.Q1, the debt-to-GDP ratio and the real stock price, negatively affected by the real lending rate and inflation expectations, and is not influenced by the real oil price. Conclusions - Real depreciation of the ringgit after 2010. Q3 or sustainable expansionary fiscal policy would be beneficial to the economy.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.2166-2178
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• 2010

현재 철도계획에 이용되고 있는 교통수요예측 지역간기종점(OD)자료는 국가교통데이타베이스(KTDB)를 이용하고 있다. KTDB의 자료는 우리나라 지역간 총통행량을 조사한 후 도로, 철도, 항공등으로 배분하는 방법을 이용하고 하고 있다. 그러나 철도의 경우는 철도역이 기존의 존과 일치하지 않거나 1개존에 다수의 철도역이 존재하여 Connector가 연결되지 않아 적용 방법상에 문제점이 있는 것으로 나타났다. 이로 인해 KTDB를 이용한 철도부분의 교통예측은 다른 교통수단에 비해 신뢰성이 크게 떨어지고 있다. 본 연구는 이러한 문제점을 검토 분석하고, 신뢰성을 높이기 위해 집계모형(Aggregate Model) 기법을 활용한 철도의 교통수요예측 방법(직접수요추정 : Direct Demand Estimation)을 제안하였다. 본 연구에서는 집계모형에 지역간의 인구, 거리, 산업체종사자수, 자동차대수, 도로연장등 사회경제지표의 연관성을 분석하여 철도분야 수요예측의 오차를 최소화할 수 있는 방법을 연구하였다.

• Computers and Concrete
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• 제23권1호
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• pp.69-80
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• 2019

Modeling approach for mesoscopic model of concrete depicting mass transportation and physicochemical reaction is important since there is growing demand for accuracy and computational efficiency of numerical simulation. Mesoscopic numerical simulation considering binder, aggregate and Interfacial Transition Zone (ITZ) generally produces huge number of DOFs, which is inapplicable for full structure. In this paper, a three-dimensional multiscale approach describing three-phase structure of concrete was discussed numerically. An effective approach generating random aggregate in polygon based on checking centroid distance was introduced. Moreover, ITZ elements were built by parallel expanding the surface of aggregates on inner side. By combining mesoscopic model including full-graded aggregate and macroscopic model, cases related to diffusivity and thickness of ITZ, volume fraction and grade of aggregate were studied regarding the consideration of multiscale compensation. Results clearly showed that larger analysis model in multiscale model expanded the diffusion space of chloride ion and decreased chloride content in front of rebar. Finally, this paper addressed some worth-noting conclusions about the chloride distribution and rebar corrosion regarding the configuration of, rebar diameter, concrete cover and exposure period.

• Industrial Engineering and Management Systems
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• 제6권2호
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• pp.106-118
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• 2007

This paper present a new optimization model to generate aggregate production planning by considering electric cost. The new Time Of Switching (TOS) electric type is introduced by switching over Time Of Day (TOD) and Time Of Use (TOU) electric types to minimize the electric cost. The fuzzy demand and Dynamic inventory tracking with multiple plant capacity are modeled to cover the uncertain demand of customer. The constraint for minimum hour limitation of plant running per one start up event is introduced to minimize plants idle time. Furthermore; the Optimal Weight Moving Average Factor for customer demand forecasting is introduced by monthly factors to reduce forecasting error. Application is illustrated for multiple cement mill plants. The mathematical model was formulated in spreadsheet format. Then the spreadsheet-solver technique was used as a tool to solve the model. A simulation running on part of the system in a test for six months shows the optimal solution could save 60% of the actual cost.

• Industrial Engineering and Management Systems
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• 제13권3호
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• pp.319-329
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• 2014

Supply chain management is a subject that has an increasing importance due to the developments in the global markets and technology. In this paper, a fuzzy multi-objective linear programming model is developed for the supply chain of a company dealing with procurement, storage, filling, and distribution of liquefied petroleum gas (LPG) in Turkey. The model intends to determine the quantities of LPG to be procured, stored, filled to cylinders, and transported between the plants and demand centers for six planning periods. In this model, which aims to minimize both total costs (sum of procurement, storage, filling, and transportation costs) and total transportation distances, demand quantities of the main demand centers and decision maker's aspiration levels about objective functions are fuzzy. After comparing the results obtained from the model with those obtained by using different methods, it is concluded that the proposed method can be applied to real world problems practically and it may be used in this type of problems in order to generate an efficient solution.