• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.66-76
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• 2023

The government recently implemented policies to improve transportation for the disabled passengers. On the other hand, metropolitan public transport still lacks adequate services for these individuals. Many new cities lack urban rail lines and focus on high-floor buses for expansion. Wheelchair users can only access to double-decker low-floor seat express buses for intercity travel. This study examined the necessity and rationale for introducing low-floor seat buses by estimating the user's willingness to pay through a contingent valuation method. Two methods for eliciting the willingness to pay were adopted: open-ended and dichotomous choice questions. The binomial logit model was used to estimate the willingness to pay. The results indicated that the general public is willing to pay an additional 126.7 Korean won, while the disabled passengers are willing to pay an additional 117.5 Korean won. When translated into annual economic benefits, this amounts to approximately 35 billion Korean won.

• Environmental and Resource Economics Review
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• v.22 no.3
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• pp.521-545
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• 2013

This study applied choice experiment(CE) method(which is included in the stated preference method) to estimate values of some important attributes(i.e. type of estuary, water quality of river in estuary, water quality of sea in estuary, biodiversity level of estuary) of 4 major river(Hangang, Guemgang, Yeongsangang, Nakdonggang) estuaries in Korea. Although the multinomial logit model(MNL) is generally applied to analyse the CE data, testing for IIA assumption with the Hausman and McFadden test in MNL model shows that the IIA assumption in our data is rejected. Therefore, the heteroscedastic extreme value model(HEV) and the multinomial probit model(MNP) which are not based on the IIA assumption are used to analyse our CE data. As results, the coefficients and the elicited economic values of MNL model are seriously distorted if the IIA assumption is not satisfied in MNL model. The estimation results of MNP model show that the economic values are elicited as 352.3 billion won(95% C.I. 261.1 - 477.8 billion won) for natural estuary, 411.5 billion won(95% C.I. 338.5 - 525.5 billion won) for one grade improvement of river water quality in estuary, 358.9 billion won(95% C.I. 292.5 - 457.0 billion won) for one grade improvement of sea water quality in estuary, and 151.9 billion won(95% C.I. 99.0 - 218.6 billion won) for one grade improvement of biodiversity level of estuary. Therefore, the value of estuary is reached to 2,197.0 billion won(95% C.I. 1,721.0 - 2,879.9 billion won) if any natural estuary in 4 major rivers has good water quality of river in estuary(i.e. 2nd grade), good water quality of sea in estuary(i.e. 1st grade), and good biodiversity level of estuary.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.117-130
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• 2005

In both deteministic user Optimal Traffic Assignment Model (UOTAM) and stochastic UOTAM, travel time, which is a major ccriterion for traffic loading over transportation network, is defined by the sum of link travel time and turn delay at intersections. In this assignment method, drivers actual route perception processes and choice behaviors, which can become main explanatory factors, are not sufficiently considered: therefore may result in biased traffic loading. Even though there have been some efforts in Stochastic UOTAM for reflecting drivers' route perception cost by assuming cumulative distribution function of link travel time, it has not been fundamental fruitions, but some trials based on the unreasonable assumptions of Probit model of truncated travel time distribution function and Logit model of independency of inter-link congestion. The critical reason why deterministic UOTAM have not been able to reflect route perception cost is that the route perception cost has each different value according to each origin, destination, and path connection the origin and destination. Therefore in order to find the optimum route between OD pair, route enumeration problem that all routes connecting an OD pair must be compared is encountered, and it is the critical reason causing computational failure because uncountable number of path may be enumerated as the scale of transportation network become bigger. The purpose of this study is to propose a method to enable UOTAM to reflect route perception cost without route enumeration between an O-D pair. For this purpose, this study defines a link as a least definition of path. Thus since each link can be treated as a path, in two links searching process of the link label based optimum path algorithm, the route enumeration between OD pair can be reduced the scale of finding optimum path to all links. The computational burden of this method is no more than link label based optimum path algorithm. Each different perception cost is embedded as a quantitative value generated by comparing the sub-path from the origin to the searching link and the searched link.

• Health Policy and Management
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• v.30 no.4
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• pp.493-504
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• 2020

Background: There have been many studies on the associations between body mass index (BMI) and cognitive function. However, no study has ever compared the associations across the methods of categorizing BMI. In this study, we aimed to fill the gap in the previous studies and examine whether the obesity paradox is valid in the risk of cognitive function. Methods: Of the 10,254 people aged 45 and older from the Korean Longitudinal Study of Ageing from 2006 to 2016, 8,970 people were finalized as the study population. The dependent variable was whether a person has a normal cognitive function or not, and the independent variables of interest were BMI categorized by the World Health Organization Western Pacific Regional Office (WHO-WPRO) method, the WHO method, and a 10-group method. Covariates included sociodemographic factors, health behavior factors, and health status factors. A generalized linear mixed model analysis with a logit link was used. Results: In the adjusted model with all covariates, first, in the case of BMI categories of the WHO-WPRO method, underweight (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.15-1.17), overweight (OR, 1.36; 95% CI, 1.35-1.36), and obese (OR, 1.34; 95% CI, 1.33-1.34) groups were more likely to have a normal cognitive function than a normal-weight group. Next, in the case of BMI categories of the WHO method, compared to a normal-weight group, underweight (OR, 1.15; 95% CI, 1.14-1.16) and overweight (OR, 1.06; 95% CI, 1.06-1.07) groups were more likely to have a normal cognitive function; however, obese (OR, 0.62; 95% CI, 0.61-0.63) group was less likely to have it. Lastly, in the case of the 10-group method, as BMI increased, the likelihood to have a normal cognitive function changed like a wave, reaching a global top at group-7 (26.5 kg/㎡ ≤ BMI <28.0 kg/㎡). Conclusion: The associations between BMI and cognitive function differed according to how BMI was categorized among people aged 45 and older in Korea, which suggests that cognitive function may be positively associated with BMI in some categories of BMI but negatively in its other categories. Health policies to reduce cognitive impairment need to consider this association between BMI and cognitive function.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.211-221
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• 2008

This dissertation studied the psychological cost, which converted the mental pain suffered by the victim of a traffic accident and his/her family, friends and people around him/her into social costs. Three methodologies - Choice Experiments, Direct Question and Dichotomous Choice Question - were used to design questionnaires, and models were built for each questionnaire design method. When building models, a logit model was used, which is used most frequently in probabilistic choice model. And the tobitmodel was used to make direct questionnaires. When verifying these models, although there were some differences in each model, suitability of most models and credibility of each coefficient were meaningful around the credibility level of 95%. According to the analysis, domestic psychological cost produced through the assessment model of psychological cost was 15.63 million won per person or 5.1 trillion in total, assuming 37.1% of total traffic accident cost.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.123-130
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• 2006

This is a basic study to investigate possibility to application of cohousing model into Korea. Purpose of this study is to grasp respondents' housing value, and its influence on intention to live in cohousing. Research method used for this study was a social survey. Respondents were 214 married people residing in Seoul and its outskirts by accidential sampling. The collected data were analyzed by SPSS 12.0 program using frequency, mean, average, factor analysis, t-test, one-way ANOVA, Duncan's multiple range test, multiple regression and logit analysis. Result of this study was as follows. Housing values were classified into three categories named as individualism oriented housing value, tradition oriented housing value, and economy oriented housing value. Housing values were different by respondents groups. For example, individualism oriented housing value showed difference according to age and housing area. Tradition oriented housing value showed difference according to sex, occupation, and period of residence, while economy oriented housing value showed difference according to number of family members, housing type, and home ownership. In detail, men than women, single-income family than double-income family, and detached house resident than flat resident had higher tradition oriented housing value. The younger than the elder, and Seoul resident than outskirts resident had higher economy oriented housing value. Also home owner than tenant, and the higher tradition oriented group had stronger intention to live in cohousing than others.

• Journal of the Korea Society of Computer and Information
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• v.19 no.10
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• pp.125-133
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• 2014

This paper develops a bankruptcy prediction model on an Artificial Neural Network for hotel management. A bankruptcy prediction model has a specific feature to predict a bankruptcy of the whole hotel business after evaluate bankruptcy possibility on the basis of business performance data of each branch. here are many traditional statistical models for bankruptcy prediction such as Multivariate Discriminant Analysis or Logit Analysis. However, we chose Artificial Neural Network because the method has accuracy rates of prediction better than those of other methods. We first selected 100 good enterprises and 100 bankrupt enterprises as experimental data and set up a bankruptcy prediction model by use of a tool for Artificial Neural Network, NeuroShell. The model and its experiments, which demonstrated high efficiency, can certainly provide great help in decision making in the field of hotel management and in deciding on the bankruptcy or financial solidity of each branch of serviced residence hotel.

• Journal of Soil and Groundwater Environment
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• v.13 no.6
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• pp.1-16
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• 2008

There are generally two types of groundwater vulnerability assessments. Intrinsic vulnerability is based on the assessment of natural climatic, geological and hydrogeological attributes and specific vulnerability relates to a specific contaminant, contaminant class, or human activity. Several methods to assess groundwater vulnerability, which are based on hydrogeologic setting and socio-economical environment, have been developed in USA and Europe. A Modified-DRASTIC model including a lineament factor has been developed in South Korea, but it still has some limitations. To develop a solid and applicable method in this country, many data of quality, hydraulic features, GIS data, and pollution source, produced from a Basic Survey based on Article 5 of the Groundwater Act and other research projects, need to be collected, analyzed and verified introducing the previous methods.

• Journal of Korean Society of Transportation
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• v.20 no.7
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• pp.167-175
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• 2002

The objective of this study is to reveal a shipper's preference for road freight transport according to commodity classification code. The shipper's preference in freight transport can be obtained by using value of travel-time savings. The characteristics of freight are so various that the shipper's preference also appear widely different. In these days, there were few attempts to estimate value of freight travel-time savings in Korea. but most of them included only rail or marine freight transport so it couldn't obtain unique travel-time savings for road freight transport. In this study the value of travel-time savings of road freight transport was estimated according to commodity classification code. Revealed preference method and associated binominal logit models were applied to estimate the value of travel-time savings in transit from a Seoul metropolitan commodity flow survey data in 1998. Data sets were segmented by commodity classification code and nineteen binominal legit models were estimated according to segmented groups. The results of this study showed that the value of freight travel-time savings varied wide ranges from 16,441 won to 66,769 won per hour a vehicle along with commodity classification code.

• Journal of Korea Trade
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• v.25 no.2
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• pp.111-133
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• 2021

Purpose - Although remittance payment in international trade settlements has played a bigger role in recent years, scant research is being done. This study is to zero in on analyzing determinants of international trade payments focused on remittance by constructing a payment prediction model. Design/methodology - This study categorizes the types of trade payments into advance remittance, post remittance, linked remittance, letter of credit, and mixed payment, and analyzes these after constructing a logit model. For empirical analysis, 147 survey data were collected for export manufacturers in Korea, and binominal logistic regression analysis was used to analyze the type of payment method the exporter chooses for trade transactions. Findings - The likelihood of choosing advance remittance increased as the exporters had non-recovery experiences with payments, and decreased as the market power of importers increased. The possibility of post remittance increased when the export amount was large and the character of the buyer was reliable. In the case of linked remittance, it was highly likely to be selected when payment efficiency was important in trade settlement. In addition, when competition among companies in the global market is intense and market uncertainty is high, the possibility of using a letter of credit decreases. It was also found that the greater the export amount, the greater the possibility of choosing advance remittance, and even if the transaction period was longer, exporters using a letter of credit continued to use it. Originality/value - Despite the high proportion of remittances in international trade settlements, it has been hard to find studies that reflect the practical characteristics of remittances. This study classified the types of remittance into advance remittance, post remittance, and linked remittance, and built a trade payment prediction model by adding a letter of credit and mixed payment. In addition, the originality of this study is recognized in that a logistic model was constructed and meaningful results were derived.