• 농촌계획
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• 제15권2호
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• pp.97-110
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• 2009

The objective of this research was to develop a rural settlement demand model to analyze the determinants of settlement demand of urban residents. The point aimed at from model development was deriving stated preference of potential consumers towards rural settlement through setting a hypothetical market, and using settlement subsidy as a surrogate variable for price in the demand model. The adequate demand model deducted from hypothetical market data was derived from the basis of Hanemann's utility difference theory. In the rural settlement demand model, willingness to accept was expressed by a function of settlement subsidy. Data utilized in the analysis was collected from surveys of households nationwide. According to inferred results of the demand model, settlement subsidy had a significant influence on increasing demand for rural settlement. A significant common element was found among variables affecting demand increase through demand curve shift. The majority group of those with high rural settlement demand sought agricultural activity as their main motive, due to harsh urban environments aggravated by unstable job market conditions. Subsequently, restriction of income opportunities in rural areas does not produce an entrance barrier for potential rural settlers. Moreover, this argument could be supported by the common trend of those with high rural settlement demand generally tending to have low incomes. Due to such characteristics of concerned groups of rural settlement demand, they tended to react susceptibly to the subsidy provided by the government and local autonomous entities.

• 한국산림과학회지
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• 제95권2호
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• pp.203-208
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• 2006

This study compared the roundwood demand prediction accuracy of econometric and time-series models using Korean data. The roundwood was divided into softwood and hardwood by species. The econometric model of roundwood demand was specified with four explanatory variables; own price, substitute price, gross domestic product, dummy. The time-series model was specified with lagged endogenous variable. The dummy variable reflected the abrupt decrease in roundwood demand in the late 1990's in the case of softwood roundwood, and the boom of plywood export in the late 1970's in the case of hardwood roundwood. On the other hand, the prediction accuracy was estimated on the basis of Residual Mean Square Errors(RMSE). The results showed that the softwood roundwood demand prediction can be performed more accurately by econometric model than by time-series model. However, the hardwood roundwood demand prediction accuracy was similar in the case of using econometric and time-series model.

• 한국ITS학회 논문지
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• 제9권3호
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• pp.30-40
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• 2010

고속도로 본선 정체의 원인으로 진출램프에서 발생한 대기행렬의 본선 역류가 크게 작용하며, 이에 고속도로 진출램프 대기행렬 발생으로 인한 본선 영향을 적절히 표현하는 연속류 모형과 실제 제어 시 기반이 되는 적용성 연구가 필요하다. 본 연구에서는 고속도로 용량 변화에 따른 공급과 수요 곡선을 탄력적으로 적용하여 진출램프 대기행렬 영향으로 인한 고속도로 본선 교통류를 표현할 수 있는 Supply-Demand 모형의 적용성을 평가하였다. 먼저 Supply-Demand 모형 적용 시 요구되는 입력자료인 구간별 Sending & Receiving function과 진출램프 대기행렬의 본선 영향 등을 고려한 고속도로 본선 용량제약을 처리하는 방안을 제시하였다. 실시간 data를 사용하여 Supply-Demand 모형을 적용하는 일련의 과정을 모형화 한 후, 극심한 상습정체가 발생하는 내부순환로의 홍은진출을 포함하는 구간에 적용, 조정 및 발전시켜 분석하였다. 적용결과, 대기행렬의 본선 영향 범위와 대기행렬 패턴이 실제 교통류와 유사하게 예측되었다. 즉, Supply-Demand 모형이 Sending & Receiving function을 탄력적으로 적용함으로써, 진출램프 대기행렬의 본선 역류 등으로 인한 고속도로 본선의 용량 변화가 적절히 반영되는 것으로 검증되었다.

• 상하수도학회지
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• 제20권2호
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• pp.187-196
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• 2006

Forecasting the long-term water demand is important in the plan of water supply system because the location and capacity of water facilities are decided according to it. To forecast the long-term water demand, the existing method based on lpcd and population has been usually used. But, these days the trend among the variation of water demand has been disappeared, so expressing other variation of it is needed to forecast correct water demand. To accomplish it, we introduced the System Dynamics method to consider total connections of water demand factor. Firstly, the factors connected with water demand were divided into three sectors(water demand, industry, and population sectors), and the connections of factors were set with multiple regression model. And it was compared to existing method. The results are as followings. The correlation efficients are 0.330 in existing model and 0.960 in SD model and MAE are 3.96% in existing model and 1.68% in SD model. So, it is proved that SD model is superior to the existing model. To forecast the long-term water demand, scenarios were made with variations of employment condition, economic condition and consumer price indexes and forecasted water demands in 2012. After all scenarios were performed, the results showed that it was not needed to increase the water supply ability in Seoul.

• 전기학회논문지
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• 제62권8호
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• pp.1074-1079
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• 2013

Demand response(DR) is potential generation alternative to improve the reliability indices of system and load points. However, when demand resources scheduled in DR market fail to reduce demand, it can create new problems associated with maintaining a reliable supply. In this paper, a reliability model of demand resource is constructed considering customers' behaviors in the same form as conventional generation units, where availability and unavailability are associated with the simple two-state model. As a result, the generalized reliability model of demand resources is represented by multi-state model.

• 경영과학
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• 제25권1호
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• pp.93-106
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• 2008

This study is focused on the problem of seat allocation for group travel demand in airlines. We first explain the characteristic of group demand and its seat allocation process. The group demand in air travel markets can be classified into two types : incentive and package groups. Allocating seats for group demand depends on the types of group demand and the relationship between airlines and travel agents. In this paper we concentrate on the package group demand and develop an optimization model for seat allocation on the demand to maximize the total revenue. With some assumptions on the demand distribution and the linear approximation technique, we develop a mixed IP model for solving our problem optimally. From the computational experiments, we can find our optimization model can be applied well for real-world application.

• 한국항만경제학회지
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• 제37권1호
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• pp.71-85
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• 2021

기업이 물류비용을 절감할 수 있는 정교한 수요 예측 모형은 그동안 수많은 연구를 통해 다양한 방법들이 제시되었다. 이러한 연구들은 주로 수요 패턴에 의해서 적용 가능한 수요 예측 모형을 결정하고, 통계적 검증을 통해서 모형의 정확성을 판단하였다. 수요 패턴은 크게 규칙성과 불규칙성으로 나뉘어 질 수 있다. 규칙적인 패턴은 주문이 정기적이고 주문량이 일정한 경우를 의미한다. 이러한 경우에는 주로 회귀모형이나 시계열 모형을 통해서 수요를 예측하는 방법들이 사용된다. 그러나 불규칙적이고 주문량의 변동 폭이 큰 경우는 간헐적 수요(Intermittent Demand)라고 하는데, 기존의 회귀 모형이나 시계열 모형으로는 수요 예측의 오류 발생 가능성이 높기 때문이다. 간헐적 수요를 보이는 품목에 대해서는 주로 Croston모형 혹은 Holts모형 등을 사용하여 수요를 예측한다. 본 연구에서는 간헐적 수요 패턴을 보이는 항공 화물의 다양한 품목에 대해서 수요 패턴을 분석하고, 다양한 모형을 통해 수요를 예측하여 각 모형의 예측력을 비교 분석하였다. 이 과정에서 항공 화물의 품목별, 지역별로 다양한 모형의 적합도를 분석하여 항공사가 가장 효율적으로 운영할 수 있는 항공 화물의 수요 예측 모형에 대한 개발 방향을 제시하고자 함이 본 논문의 목적이다.

• 전기학회논문지P
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• 제63권4호
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• pp.307-311
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• 2014

Due to the increasing of power consumption, it is difficult to construct accurate prediction model for daily peak power demand. It is very important work to know power demand in next day for manager and control power system. In this research, we develop a daily peak power demand prediction method considering of characteristics of day of week. The proposed method is composed of liner model based on AR model and nonlinear model based on ELM to resolve the limitation of a single model. Using data sets between 2006 and 2010 in Korea, the proposed method has been intensively tested. As the prediction results, we confirm that the proposed method makes it possible to effective estimate daily peak power demand than conventional methods.

• 대한산업공학회지
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• 제39권4호
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• pp.247-252
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• 2013

Korea gas corporation (KOGAS) is responsible for the whole sale of natural gas in the domestic market. It is important to forecast the daily demand of city gas for supply and demand control, and delivery management. Since there is the autoregressive characteristic in the daily gas demand, we introduce a modified autoregressive model as the first step. The daily gas demand also has a close connection with the outdoor temperature. Accordingly, our second proposed model is a temperature-based model. Those two models, however, do not meet the requirement for forecasting performances. To produce acceptable forecasting performances, we develop a weighted average model which compounds the autoregressive model and the temperature model. To examine our proposed methods, the forecasting results are provided. We confirm that our method can forecast the daily city gas demand accurately with reasonable performances.

• 대한교통학회지
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• 제36권2호
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• pp.141-154
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• 2018

지속적으로 증가하는 국제선 항공수요에 대웅하기 위해 지방 광역권에도 새로운 공항 건설 및 기존 공항 확장 계획이 이루어지고 있다. 그러나 기존 항공수요예측은 우리나라 전체 항공수요 또는 주요 도시 간의 항공수요에 대해서 수행되어 왔으며, 지방의 고유 특성을 고려한 지역별 항공수요예측은 많이 이루어지지 않았다. 본 연구에서는 영남권 국제선 항공수요를 대상으로 하였고, 현실적으로 관측하기 어려운 지방 광역권의 고유 특성을 반영할 수 있는 패널 자료를 활용한 fixed-effects model을 최적 모형으로 제안하였다. 모형 검증결과를 살펴보면 패널 자료 분석은 시계열 특성을 가지는 몇 개의 거시 사회경제지표만을 사용한 모형에서 다루기 어려운 허구적 회귀와 미관찰 이질성을 효과적으로 처리하고 있음을 알 수 있다. 다양한 통계적 검증과 적합성 평가를 통해서 본 연구에서 제안한 fixed-effects model이 다른 계량경제 모형들에 비해서 영남권 국제선 수요예측에 있어서 우수함을 증명하였다.