• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1810-1815
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• 2003

Sliding mode control with nonlinear interpolation in the boundary layer is proposed. A modified sigmoid function is used for nonlinear interpolation in the boundary layer and its parameter is tuned by a fuzzy logic controller. The fuzzy logic controller that takes the distance between the system state and the sliding surface as its input guides the choice of parameter of the modified sigmoid function and the parameter is on-line tuned. Owing to the decreased thickness, the proposed method has better tracking performance than the conventional linear interpolation method. To demonstrate its performance, the proposed control algorithm is applied to a simple nonlinear system model.

• The Korean Journal of Applied Statistics
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• v.26 no.4
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• pp.623-634
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• 2013

In this study, we provide empirical evidence of whether a spatial correlation among mode choices at the TAZ(Traffic Analysis Zone) level exists based on transit smart card data observed in Seoul, Korea. The results show that the areas with a higher probability that passengers choose to take a bus are clustered and that those regions have fewer metro stations than bus stations. We also found that the spatial correlation turned out to be statistically meaningful and provided an opportunity for the potential use of the spatial correlation in modeling mode choices. A reliable spatial interaction would constitute valuable information for transportation agencies in terms of their route planning and scheduling based on the transit smart card data.

• Journal of Korean Society of Transportation
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• v.30 no.1
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• pp.7-18
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• 2012

This study suggested a method of forecasting market-share of each mode after introducing new urban rail transit lines. The study reflected the observed market share of presently operating urban rail transit into forecasting process in order to improve accuracy in predicting market share of each modes. For more realistic representation of the forecasting model, we categorized O/D pairs according to attributes of trip distance, access time and number of transfers. The analysis results of traveler's mode choice behavior with observed data showed that the trip distances are longer, the share of urban rail tends to be higher, and that the number of transfers is fewer and the access times are lesser, the share of urban rail also tends to be higher. Then, incremental logit model was used in estimating mode choice probabilities for O/D pairs along with rail transit lines while utilizing observed market shares of each modes and differences in transit service level. As the next step, the market share of rail transit after introducing new rail transit lines was forecasted by using incremental logit model with the intial share values calculated the previous analysis step. It also reflected changes in level of service for automobile in highway due to changes in highway systems and changes in mode shares after introducing new lines of rail transit. It can be expected that the proposed method would more realistically duplicates phenomena of mode choice behavior for rail transit and that it would be more theoretically logical than the typical existing methods using SP data and incremental logit model or using addictive logit model in this country.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.875-886
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• 2015

By promoting the international transportation and the improvement of advanced exchange between South and North Korea, the Asian Highway plan was expected to make considerable economical effects in the North-East Asian region. This study focuses on a part of AH6 route (i.e., South Korea-North Korea-China-Far East Russia) and aims to analyze the behavioral change of international passenger transport around the Korean Peninsula by assuming the non-existent North Korea land transport network connectivity. The study was performed using two main methods. First, a stated preference survey was performed to derive the actual modal share of each travel mode. Second, a disaggregate analysis was performed to develop possible mode-choice models for international passenger travel and find out the suitable choice. Based on the results of the model estimation, it is found that over 90% of the international passenger transport would be converted to land transport (rail+highway). In addition, international railroad modal share rate would be increased from 62.8% to 66.1% and international bus would be decreased from 29.6% to 21.9% as the distance lengthened (903km~1,631km).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6D
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• pp.565-569
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• 2012

This study selected blind spot areas for public transportation in four metropolitan cities including Busan, Daegue, Gwangju, and Daejeon. Then this study developed a nested logit model and analyzed the changes of mode choice behaviors after adopting rapid transit system using stated preference(SP) survey. As the study results, blind spot areas have more potential public transportation demand and tendency to shift to public transportation from autos than built-up areas. This study results can be utilized to evaluate demand changes for new rapid transit system in a circular expressway and an arterial highway connecting CBD and surrounding areas. The study results also can be utilized to analyze the potential public transportation demand in the surrounding areas.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6D
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• pp.697-705
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• 2010

The purpose of this research is to clarify the relation between environmental consciousness and railway usage behavior. Author would locate this research on position of basic survey to promote railway use according to Low Carbon Green Growth policy in Korea. In this research, we would perform descriptive analysis using data of research on the actual condition of railway use in 2008, Daegu, and describe its relationship. In addition, we would suggest some idea about policy which can promote railway use. The order of railway choice behavior noticed in clustering of environmental consciousness was cooperative behavior type, middle type and non-cooperative behavior type. It suggests that environmental consciousness has effect on transportation choice behavior. Specially, railway improvement isn't enough to promote railway use. And, it is advisable to carry out the improvement in such a way that it may encourage the nation to move from the current environmental consciousness stage to cooperative behavior. Moreover, we assumed Binary Probit(BP) model using SP data of time or condition of transportation expense compared with passenger car and bus. As the results, modified likelihood ratio of two BP models is favorable variables. And it occurred that mode was transferred from passenger car to railway when it showed higher social environment consciousness and low selfish environment consciousness, because t-statistic which represents selfish environment consciousness showed significance in 95% confidence level. That is, it can be described that environment consciousness affect on the intention of railway use.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.157-168
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• 2009

The random utility theory and the multinomial logit model (including a more recent variant--the mixed multinomial logit) derived from it have constituted a back bone for theoretical and empirical analyses of various travel demand features including mode choice. In their empirical applications, however, it is customary to specify random utilities which are linear in modal attributes such as time and cost, and in socio-economic variables. The linearity helps easy derivation of important information such as value of travel time savings by calculating marginal rate of substitution between time and cost. In this paper the author focuses on the very linearity of the random utilities. Taking into account the fact that the mode chooser is also labour supplier, commodity consumer as well as leisure-seeker, the author sets up a maximization model of the traveller, which encompasses various economic activities of the traveller. The author derive from the model the indifference curve defined on the space of modal attributes, time and cost and investigate under what conditions the random utility of the traveller becomes linear. It turns out that there exist the conditions under which the random utility is really linear in modal attributes, but the property does not hold when the traveller has a corner solution on the space of modal attributes, or when the primary utility function of the traveller is directly affected by labour provided and/or the travel time itself. As a corollary of the analysis, a random utility is suggested, approximated up to the second order of the variables involved for empirical studies of the field.

• Journal of Korean Society of Transportation
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• v.26 no.6
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• pp.133-142
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• 2008

The term, travel time reliability, refers to variations in journey time that travelers cannot predict. This issue has been one of the main research topics in transport studies. This paper, especially, investigates the value of travel time reliability. The marginal substitution rate method is suggested as the way for the valuation and travelers' stated preference data are collected based on a choice experiment. A mode choice model is estimated using the data surveyed. The parameters of travel costs and travel time reliability from the model are used to calculate the marginal substitution rate that is interpreted as the value of travel time reliability. The value is arranged by travel areas of intercity and urban trips and by journey purposes of working and non-working types. The result of this research is expected to be helpful of conducting more cautious economic feasibility studies of transport schemes.

• 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.

• Journal of the Society of Disaster Information
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• v.11 no.4
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• pp.506-514
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• 2015

In this study, a new analytical techniques is proposed for seeking policy alternatives aimed at objectives of TDM, increasing the transit rideshare. Determinants of travel mode such as personal characteristics, lifestyle, and urban spatial characteristics are interdependent and have combined effect on decision. In addition, individuals, groups, and regional characteristics have interdependencies at different levels. Unlike traditional regression analysis, hierarchical analysis model has the advantage of identifying interdependencies and complex relationship between the combined impact factors. This analysis technique is expected to be a significant contribution to seek a more efficient TOD policy.