• Journal of the Korea Safety Management & Science
• /
• v.13 no.2
• /
• pp.267-273
• /
• 2011

Since 'The Act on Private Investment of The Infrastructure' was established in 1994, private investment as well as government's investment in transport infrastructure has been active. However investment in transport infrastructure has more risks than others' due to uncertainty both in traffic volume and in construction cost. In the current appraisal procedure of deciding transportation infrastructure investment, instead of risk management, the sensitivity analysis considering only the changes of benefit, cost and social discount rate which are main factor affecting economic feasibility is carried out. Therefore the uncertainty of various factors affecting demand, cost and benefit are not considered in feasibility study. In this study the problems in current investment appraisal system were reviewed. Using Delphi technique the major factors which have high uncertainty in feasibility study were surveyed and then improvement plan was suggested in the respective of classic 4 step demand forecasting method. The range estimation technique was also mentioned to deal with the uncertainty of the future.

• YAKHAK HOEJI
• /
• v.51 no.2
• /
• pp.126-132
• /
• 2007

Demand for manpower of conducting pharmaco-economic evaluation was investigated. The priority order of conducting economic evaluation on the already listed drugs was set by the budget impact for health insurance by the therapeutic groups. Manpower demand was estimated by the Anatomical, Therapeutical, Chemical (ATC) code. The total number of economic evaluation on the already listed drugs is estimated to be 346 cases. Based on these numbers, at least 53${\sim}$102 of full-time-equivalent (FTE) manpower is needed for conducting economic evaluation per year in the following 5 years.

• IE interfaces
• /
• v.18 no.2
• /
• pp.126-135
• /
• 2005

Since the alcohol involves a wide variety of adverse health and social consequences, there is a strong need for improved estimates on economic costs and benefits of alcohol drinking to reduce the social alcohol abuse and to obtain some useful informations for targeting programs. However, there is no research for the intangible costs and benefits so far that are essential to estimate the real overall costs and benefits incurred by alcohol use. Thus this paper finds out and represents a general model for estimating the intangible costs and benefits by use of alcohol demand curve. The calculated monetary values, as a example, of them in 2002 show as big as 7,900 billion won and 4,200 billion won respectively.

• Proceedings of the KOR-KST Conference
• /
• 2000.02a
• /
• pp.89-115
• /
• 2000

Traffic signal setting policies and traffic assignment procedures are mutually dependent. The combined signal control and traffic assignment problem deals with this interaction. With the total travel time minimization objective, gradient based local search methods are implemented. Deterministic user equilibrium is the selected user route choice rule, Webster's delay curve is the link performance function, and green time per cycle ratios are decision variables. Three implemented solution codes resulting in six variations include intersections operating under multiphase operation with overlapping traffic movements. For reference, the iterative approach is also coded and all codes are tested in four example networks at five demand levels. The results show the numerical gradient estimation procedure performs best although the simplified local searches show reducing the large network computational burden. Demand level as well as network size affects the relative performance of the local and iterative approaches. As demand level becomes higher, (1) in the small network, the local search tends to outperform the iterative search and (2) in the large network, vice versa.

• Journal of Environmental Science International
• /
• v.22 no.5
• /
• pp.639-649
• /
• 2013

Over 96.2% of the agricultural water in Jeju Island is obtained from groundwater and there are quite distinct characteristics of agricultural water demand/supply spatially because of regional and seasonal differences in cropping system and rainfall amount. Land use for cultivating crops is expected to decrease 7.4% (4,215 ha) in 2020 compared to 2010, while market garden including various vegetable crop types having high water demand is increasing over the Island, especially western area having lower rainfall amount compared to southern area. On the other hand, land use for fruit including citrus and mandarin having low water demand is widely distributed over southern and northern part having higher rainfall amount. The agricultural water demand of $1,214{\times}10^3\;m^3/day$ in 2020 is estimated about 1.39 times compared to groundwater supply capacity of $874{\times}10^3\;m^3/day$ in 2010 with 42.4% of eastern, 103.1% of western, 61.9% of southern, and 77.0% of northern region. Moreover, net secured amount of agricultural groundwater would be expected to be much smaller due to regional disparity of water demand/supply, the lack of linkage system between the agricultural water supply facilities, and high percentage of private wells. Therefore, it is necessary to ensure the total net secured amount of agricultural groundwater to overcome the expected regional discrepancy of water demand and supply by establishing policy alternative of regional water supply plan over the Island, including linkage system between wells, water tank enlargement, private wells maintenance and public wells development, and continuous enlargement of rainwater utilization facilities.

• Korean Journal of Construction Engineering and Management
• /
• v.20 no.3
• /
• pp.105-112
• /
• 2019

Due to abnormal high temperature, electric power demand has exceeded the backup power reserved for emergency case, hence, resulting in a major power outage. In today's overcrowded cities, the unexpected disruption in energy supply and demand is a major threat to the enormous economic damage and urban malfunctions. Existing methods for estimating the demand of the emergency power source do not lend themselves to predict the actual demand in the spatial dimension of the city. In addition, the reserve power is arbitrarily distributed in the case of emergency. This paper presents a method that predicts the emergency power demand using the spatial distribution of emergency power demand by applying the daily energy consumption intensity and emergency power demand according to urban spatial information and building use.

• 한국ITS학회:학술대회논문집
• /
• 2003.11a
• /
• pp.247-252
• /
• 2003

• 한국ITS학회:학술대회논문집
• /
• 2010.05a
• /
• pp.204-209
• /
• 2010

• Journal of Korean Institute of Industrial Engineers
• /
• v.37 no.1
• /
• pp.74-82
• /
• 2011

The Bass model is a cornerstone in diffusion theory which is used for forecasting demand of durables or new services. Three well-known estimation methods for parameters of the Bass model are Ordinary Least Square (OLS), Maximum Likelihood Estimator (MLE), Nonlinear Least Square (NLS). In this paper, a hybrid method incorporating OLS and NLS is presented and it's performance is analyzed and compared with OLS and NLS by using simulation data and empirical data. The results show that NLS has the best performance in terms of accuracy and our hybrid method has the best performance in terms of stability. Specifically, hybrid method has better performance with less data. This result means much in practical aspect because the avaliable data is little when a diffusion model is used for forecasting demand of a new product.

• Journal of the Korean Institute of Gas
• /
• v.14 no.2
• /
• pp.15-21
• /
• 2010

The demand of gas as an eco-friendly energy source has being increased. With increasing the LPG demand, the number of LPG filling station. In this work, the influence on over-pressure caused by Vapor Cloud Explosion in gas station was calculated by using the Hopkinson's scaling law and injury effect by the accident to a human body was estimated by applying the probit model. As a result of the injury estimation conducted by using the probit model for leakage 10% of 20ton storage tank. The distances from LPG station for death and tympanum rupture are 36.5 and 290 meters, respectively.