• Journal of Korean Society of Transportation
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• v.18 no.1
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• pp.27-34
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• 2000

This study analyzes the price elasticities of airline Passenger demand through the 'Stated Preference' technique which uses survey data. Because the domestic airfare has been regulated by the government. it is not easy to derive Price elasticity through the usual regression analysis with aggregate data and thus a special methodology is required for elasticity estimation. Therefore, in this study we estimated the Price elasticities of domestic air passenger demand and the modal share change rates to the alternative modes with logit model and sample enumeration method, by analyzing the survey data on air Passengers' demand behavior about the mode choice between air-rail. air-bus, and air-car. As the results, the estimated price elasticities are in the range of -0.6~-0.9, and rail is mainly chosen as an alternative mode. bus is chosen Partly, and car is barely used.

• Ocean and Polar Research
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• v.32 no.1
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• pp.23-40
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• 2010

This study investigated the effects of imported fisheries products on WTO/DDA tariff negotiations. To calculate the results, the study estimated the demand functions of imported fisheries products by using unit root and cointegration approaches. These approaches allowed us to solve spurious regression problems with macro-economic variables. In addition, this study surmised the effects of change by individually imported fish products from a tariff negotiation model using price elasticities of estimated import demand function. In a process of the analysis for estimating import effects, this study found out that 39 out of 128 imported fish products had positive (+) price elasticities or did not exhibit cointegrations. To cure this problem, this study suggested that the effects of these 39 imported products be estimated with the average variation rate of import volume, rather than by the Ordinary Least Squares approach. In this study, a case-study of tariff formula with coefficient 8 based on a 'Swiss formula' for priority duty rate of 2001 and 2008 was used by to analyze the effect of change in the 128 imported fish products of both years, respectively.

• Journal of Korean Society of Transportation
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• v.20 no.4
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• pp.63-72
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• 2002

We applied 3-D balancing technique to estimate nationwide travel demand using travel behavior of Toll Collecting System data, socio-economic data in the region, and the data of several organizations connected with travel demand estimation. The results from this study were validated by the indices of RMSE(Root Mean Square Error), TLFD(Trip Length Frequency Distribution). TCS based inter-city average travel to measure of reliability and adequacy of estimated travel demand. Finally, 3-D technique seems to reflect more travel behavior of TCS OD than 2-D technique, but we cannot assert that 3-D technique superior to 2-D technique.

• Journal of the military operations research society of Korea
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• v.35 no.3
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• pp.1-15
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• 2009

Central supply depot of Air Force has been receiving and storing the goods from the inside and outside of the country. And it also has been distributing the goods to the air base by air, rail, road, etc. These goods have been called central goods. Among these central goods, 10% of them are transported by air and the amount of freight is increasing day by day. So, air transportation in the Air Force has been more important than ever. But, studies of demand estimation for activating air transportation are very difficient. This study verified the main factors affecting to air transportation and the function of regression model will be useful data for estimating air freight demand.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.2025-2033
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• 1999

In this paper, we forecast launching time of the commercial IMT-2000 service as feb. 2001, according to expert’s opinion, and most of they forecast rapid evolution. And, we propose two different models according to two cases for competition power of price for IMT-2000 service subscriber demand forecasting. In this paper, we combine the expert’s opinion method with the growth curve model for demand forecasting for new products in order to reduce error of the demand forecasting that haven’t past references. The estimation of needed coefficients for each growth curve model is based on experts’ subjective opinions.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.4
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• pp.481-489
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• 2009

The objective of this research is to provide more reliable and accurate unit factor of water amount by investigating of informations related to various educational institutions such as elementary, middle, high schools and university. In order to estimate the water demand of educational institutions, first of all, the informations such as building area, site area, total school population, and water amount of various educational institutions are investigated to estimate the water unit factor. In this research, we used the total population of students and teachers to estimate the water demand of educational institutions. The results of unit factors of this research are as follows: 1) The elementary school is $0.027983m^3/person{\cdot}day$, 2) middle school: $0.024106m^3/person{\cdot}day$, 3) high school: $0.041415m^3/person{\cdot}day$, 4) specialized high school (science high school and foreign language high school): $0.156938m^3/person{\cdot}day$ and 5) university: $0.033766m^3/person{\cdot}day$. Finally, these water amounts calculated by unit factors were compared with real water amount of educational institutions.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.1
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• pp.95-115
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• 2012

The initial market of alternative-fuel vehicle (AFV) will show geographically uneven distribution due to AFV's high price, and thus efficient location model should consider spatial variation of demand. This paper estimates AFV trips by incorporating an AFV demand estimation model with origin-destination (OD) trips. The estimates are the input for the flow-refueling location model that maximizes the OD flows that can be refueled by the given number of stations considering AFV's limited range per refueling. A scenario analysis is conducted by varying assumptions in estimating demands and AFV acceptance rate. Optimal location alternatives for Orland metropolitan area are provided and results are compared.

• Environmental and Resource Economics Review
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• v.19 no.3
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• pp.633-658
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• 2010

In this paper, we estimate the Translog cost function in Korean manufacturing, using capital (K), labor (L), material (M), electricity (E), fuel (F) data over the period from 1970 to 2005. Especially, this paper investigates the impact of imposing concavity in the estimation of a Translog cost function. Although the value of log-likelihood is somewhat reduced in a concavity imposed function rather than a function which is not, a concavity imposed function satisfies regularity conditions (monotonicity, positivity, concavity) at all data points. We also calculate price elasticities using a concavity imposed Translog cost function. Electricity complements capital so electricity demand increases as capital demand increases. Meanwhile, electricity substitutes labor, fuel, and material. These results show that Korean manufacturing experienced a structural change of increase in electricity demand.

• Journal of Biosystems Engineering
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• v.38 no.1
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• pp.9-17
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• 2013

Purpose: The goal of this study was to develop a methodology for the demand forecast of tractor, riding type rice transplanter and combine harvester using an ARIMA (autoregressive integrated moving average) model, one of time series analysis methods, and to forecast their demands from 2012 to 2021 in South Korea. Methods: To forecast the demands of three kinds of machines, ARIMA models were constructed by following three stages; identification, estimation and diagnose. Time series used were supply and stock of each machine and the analysis tool was SAS 9.2 for Windows XP. Results: Six final models, supply based ones and stock based ones for each machine, were constructed from 32 tentative models identified by examining the ACF (autocorrelation function) plots and the PACF (partial autocorrelation function) plots. All demand series forecasted by the final models showed increasing trends and fluctuations with two-year period. Conclusions: Some forecast results of this study are not applicable immediately due to periodic fluctuation and large variation. However, it can be advanced by incorporating treatment of outliers or combining with another forecast methods.

• Journal of Soil and Groundwater Environment
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• v.24 no.2
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• pp.23-37
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• 2019

To evaluate the available groundwater supply to the agricultural water demand in the future with the climate change scenarios for 40 sub-regions in Jeju Island, groundwater recharge and the available groundwater supply were estimated using water balance analysis method. Groundwater recharge was calculated by subtracting the actual evapotranspiration and direct runoff from the total amount of water resources and available groundwater supply was set at 43.6% from the ratio of the sustainable groundwater capacity to the groundwater recharge. According to the RCP 4.5 scenario, the available groundwater supply to the agricultural water demand is estimated to be insufficient in 2020 and 2025, especially in the western and eastern regions of the island. However, such a water shortage problem is alleviated in 2030. When applying the RCP 8.5 scenario, available groundwater supply can't meet the water demand over the entire decade.