• 제목/요약/키워드: Logit Models

검색결과 210건 처리시간 0.023초

Solution Methods for OD Trip Estimation in Stochastic Assignment (확률적 통행배정하에서 기종점 통행량추정 모형의 개발)

  • Im, Yong-Taek
    • Journal of Korean Society of Transportation
    • /
    • 제24권4호
    • /
    • pp.149-159
    • /
    • 2006
  • Traditional trip tables are estimated through large-scale surveys such as household survey, roadside interviews, and license Plate matching. These methods are, however, expensive and time consuming. This paper presents two origin-destination (OD) trip matrix estimation methods from link traffic counts in stochastic assignment, which contains perceived errors of drivers for alternatives. The methods are formulated based on the relation between link flows and OD demands in logit formula. The first method can be expressed to minimize the difference between observed link flows and estimated flows, derived from traffic assignment and be solved by gradient method. The second method can be formulated based on dynamic process, which nay describe the daily movement patterns of drivers and be solved by a recursive equation. A numerical example is used for assessing the methods, and shows the performances and properties of the models.

A Study on Factors of Career Development in Scientist and Engineer Laborforce (과학기술인력의 경력개발 촉진 요인에 대한 분석)

  • Hong, Seong-Min;Chang, Sun-Mi
    • Journal of Technology Innovation
    • /
    • 제24권3호
    • /
    • pp.139-159
    • /
    • 2016
  • The purpose of this study is to find out the factors which promoting career development of scientist and engineer laborforce. We made up three logit analysis models to figure out the factors affecting the career of scientist and engineer laborforce. Dependent variables were composed of job attributes in 2011, current job attribute, changing of working conditions, efforts of job seeking, university education, and personal characters. Three analysis model were composed of demand side model which including job attributes factors, supply side model which focus on employment or university education characters and total model including the demand and the supply factors. The results showed a stable career to the development of scientist and engineer laborforce's job attributes on the demand side than the supply side, such as a college education even more important. After all, the initial stable jobs and good matching policy were the most important policies to be seated in the science and engineering professions.

Understanding Electric Vehicle Consumer in Korea Market Based Upon User and Prospective Survey (국내 전기자동차 수요층 분석: 초기 구매자와 일반 소비자 조사를 토대로)

  • Park, Jiyoung;Kim, Haegon;Kim, Chansung
    • Journal of the Korea Convergence Society
    • /
    • 제10권6호
    • /
    • pp.191-201
    • /
    • 2019
  • This study aims at understanding the fundamental characteristics of EV consumer based upon user survey and understanding the challenges to promote EV adoption in Korea. Data are obtained from two different surveys. One asked 304 EV buyers in Korea and another asked 905 prospective customer about EV awareness and perception, EV purchase intention, and etc. Analysis is composed of two parts; one is about the general characteristics and purchase intention of general consumers; another is about the intent to repurchase EV owners. We discuss the policy implications to expand EV demand in Korean market based on two purchase and repurchase logit models.

Demand Analysis of Electric Vehicle by Household Type (전기자동차의 가구유형별 수요에 대한 고찰)

  • Kim, Won Suk;Jung, Hun Young
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • 제38권6호
    • /
    • pp.933-940
    • /
    • 2018
  • The conversion of the internal combustion engine vehicle to the electric vehicle is suggested as a solution to the problem of global climate change and environmental pollution. Accordingly, this study was started to promote the use of electric vehicles. The purpose of this study is to identify the basic background knowledge and current status of electric vehicles in Korea and abroad, and expand from previous understanding on which factors affect ones choice on electric vehicles by considering individual characteristics and context in detail. In the analysis, a set of demand forecasting models were constructed by grouping the respondents based on the household characteristics as well as the vehicle ownership. At the time in need for better understanding of the feasibility of electric vehicles, it is expected that the research can assist the promotion of electric vehicles. In the follow-up study, I would like to continue the research on the activation of electric vehicles.

The Factors Affecting the Level of awareness of Life and Happiness Perceived by Youth Generation (청년세대 삶의 인식 수준과 행복도의 영향요인)

  • Kim, Jikyung
    • 한국사회정책
    • /
    • 제25권3호
    • /
    • pp.209-245
    • /
    • 2018
  • In this study, we examined at what level young people perceive their level of life and the overall degree of happiness in their lives, and empirically analyzed the factors affecting them through multiple regression and ordered logit models. As a result of the analysis, young people were more aware of the degree of overall happiness than their perception of their lives. It has been confirmed that the factors affecting the young generation's perception of the level of life and the degree of happiness are different and different factors are working on each group. In addition, it has been found that the subjective factors of psychological and emotional characteristics have a greater influence than the objective factors of social and demographic characteristics at the level of awareness of life and happiness level. However, in the case of the youth group, it was found that objective factors such as job satisfaction are the determinants that have the greatest influence on life awareness and happiness. The tendency to paradoxically respond to the current level of happiness due to despair of the future has been found to be seen in some subgroups(middle income plus working group) rather than in the whole youth generation.

Estimating a Mode Choice Model Considering Shared E-scooter Service - Focused on Access Travel and Neighborhood Travel - (공유 전동킥보드를 고려한 수단선택모형 추정 - 접근통행과 생활권통행을 중심으로 -)

  • Kim, Ji yoon;Kim, Su jae;Lee, Gyeong jae;Choo, Sangho
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • 제20권1호
    • /
    • pp.22-39
    • /
    • 2021
  • This study estimated mode choice models for access travel and neighborhood travel from an SP survey in metropolitan areas where shared e-scooter services are offered. Model results show that travel time and travel cost have negative effects on mode utility. It is also revealed that people are more sensitive to travel time in access travel, whereas they are more influenced by travel cost in neighborhood travel. Looking at individual and household attributes, it has a positive effect when under 40 yerars of age, owning bikes, being a public transportation user, while it has been shown a negative effect in less than 3 million won in monthly household income and owning individual cars.

A Study about the Presumed Economic Value of Miscanthus Landscape Conservation - Miscanthus Colonies in Youngnam Province - (억새경관보전의 경제적 가치 추정에 대한 연구 - 영남지역 대규모 억새군락을 대상으로 -)

  • Park, Seul-gi;Lee, Sang-Cheol;Kang, Gi-lae;Choi, Song-Hyun
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • 제44권4호
    • /
    • pp.1-13
    • /
    • 2016
  • To detail a picture of the economic value of Miscanthus landscape conservation in terms of cultural services aspects of Ecosystem Services, Sunghaksan(Mt.), Hwawangsan(Mt.) and Jaeyaksan(Mt.), which are known for their Miscanthus colonies, were chosen as survey sites. After examining the willingness to pay for the value of Miscanthus landscape conservation by targeting of visitors each study area, the economic value of Miscanthus landscape conservation per capita aspects was evaluated using Contingent Valuation Methods(CVM) from the collected willingness to pay for economic value of Miscanthus scenery by site. After using the target Chi-square test to analyze the differences among each site, the correlation between specific variables was investigated. Willingness to pay for the Miscanthus landscape conservation was found to increase as the respondents' income became higher. The more environmental conservation efforts were being made in their daily life, the higher willingness to pay was for Miscanthus landscape conservation. Likewise in other studies, the higher the bid was, the less willingness to pay was. The per capita assessment of the Miscanthus landscape value of the logit models in the dual estimated using the factor extracted with each of the injected variable bounds was estimated for Seunghaksan (\38,277), Hwawangsan(\38,648), and Jaeyaksan(\48,891). The average of the three sites was estimated to be \38,679. Assessment of the economic value of these Miscanthus landscape sites saw high willingness to pay by visitors when compared to the current market price inflation, such as watching movies or amusement park admission, which could mean that visitors recognize the value of ecosystem services from nature in evaluating the Miscanthus landscape.

Debt Issuance and Capacity of Korean Retail Firms (유통 상장기업들의 부채변화에 관한 연구)

  • Lee, Jeong-Hwan;Son, Sam-Ho
    • Journal of Distribution Science
    • /
    • 제13권9호
    • /
    • pp.47-57
    • /
    • 2015
  • Purpose - The aim of this paper is to investigate the explanatory power of the Pecking-order theory (the cost of financing increases with asymmetric information) among Korean retail firms from the perspective of debt capacity. According to the Pecking-order theory, a firm's first preference is to use internal funds for its capital needs, its next preference is the issuance of debt, and its last preference is the issuance of equity; this is due to the information asymmetry problem between existing shareholders and investors. However, prior empirical studies, such as Lemmon and Zender (2010), argue that the entire sample test for the Pecking-order theory could be misleading due to the different levels of debt issuance capability of each of the individual firms; in fact, they confirm that the explanatory power of the Pecking-order theory improves after taking into account the differences in debt capacity of the U.S. firms they examined. This paper implements a case study approach among Korean retail firms to examine the relationship between debt capacity and the explanatory power of the Pecking-order theory in Korea. Research design, data, and methodology - This study uses the sample of public retail firms on the Korea Composite Stock Price Index (KOSPI) from the time period of 1990 to 2013. We gather related financial and accounting statements from the financial information firm WISEfn. Credit rating information is provided by the Korea Investor Service. We employ the models of Lemmon and Zender (2010) and Son and Kim (2013) to measure a firm's debt capacity. Their logit models use the rating dummy variable as a dependent variable and incorporate other firm characteristics as independent variables to estimate debt capacity. To test the Pecking-order theory, we adopt variants of the financing deficit model of Shyam-Sunder and Myers (1999). In the test of the Pecking-order theory, we consider all of the changes in total debt obligations, current debt obligations, and long-term debt obligations. Results - Our main contribution to the literature is our confirmation of the predicted relationship between debt capacity and the explanatory power of the Pecking-order theory among Korean retail firms. The coefficients on financing deficits become greater as a firm's debt capacity improves. This is consistent with the results of Lemmon and Zender (2010). The coefficients on the square of the financing deficits are also negative for the firms in the largest debt capacity group, which is also consistent with the predictions in prior literature. Conclusions - This study takes a case study approach by examining Korean retail firms. We confirm that the Pecking-order theory explains the capital structure of retail firms more appropriately, after taking into account the debt capacity of each firm. This result suggests the importance of debt capacity consideration in the testing of the Pecking-order theory. Our result also implies that there has been a potential underestimation of the explanatory power of the Pecking-order theory in existing studies.

Option-type Default Forecasting Model of a Firm Incorporating Debt Structure, and Credit Risk (기업의 부채구조를 고려한 옵션형 기업부도예측모형과 신용리스크)

  • Won, Chae-Hwan;Choi, Jae-Gon
    • The Korean Journal of Financial Management
    • /
    • 제23권2호
    • /
    • pp.209-237
    • /
    • 2006
  • Since previous default forecasting models for the firms evaluate the probability of default based upon the accounting data from book values, they cannot reflect the changes in markets sensitively and they seem to lack theoretical background. The market-information based models, however, not only make use of market data for the default prediction, but also have strong theoretical background like Black-Scholes (1973) option theory. So, many firms recently use such market based model as KMV to forecast their default probabilities and to manage their credit risks. Korean firms also widely use the KMV model in which default point is defined by liquid debt plus 50% of fixed debt. Since the debt structures between Korean and American firms are significantly different, Korean firms should carefully use KMV model. In this study, we empirically investigate the importance of debt structure. In particular, we find the following facts: First, in Korea, fixed debts are more important than liquid debts in accurate prediction of default. Second, the percentage of fixed debt must be less than 20% when default point is calculated for Korean firms, which is different from the KMV. These facts give Korean firms some valuable implication about default forecasting and management of credit risk.

  • PDF

A Relation between Family Values and Needs for Care-Support Family Policy (가족가치관과 돌봄노동지원정책 욕구의 관련성 연구)

  • Byun, Joo-Soo;Chin, Mee-Jung
    • Journal of Families and Better Life
    • /
    • 제26권5호
    • /
    • pp.259-277
    • /
    • 2008
  • Traditional familism and family value is known as the value that most Koreans share with. Strong family solidarity and family-centered perception among Koreans influences other social values and ideology. Under the family value, caring for family members is family responsibility instead of government responsibility. Previous studies argued that the family value played a role to impede the development of family policy in Korea. The aim of this study was to explore a relation between the family value and the needs for care-support family policy. This study investigated how the family value were related to the specific needs for care-support family policy. The data were drawn from the Seoul Families Survey conducted on 2006 by Seoul Women and Family Foundation. The survey data consisted of 2,500 married males and females living in Seoul. The statistical techniques used for analysis were frequencies, means, t-test, ANOVA, crosstabs, multiple regression models, and multinomial logit models. The major findings of this study were as followings. First, while the traditional familism appeared to be held at a certain level, the general attitudes towards cohabitation, divorce, and single-parent family seemed to be less traditional. Second, the familism was found to be partly associated with the needs for the care-support family policy. The respondents who had less traditional value on arriage and child-rearing showed the higher level of needs for daycare center. This finding implied that nontraditional attitudes were related to the needs for an alternative care service such as caring through facilities rather than to the needs for supportive or complementary services. Lastly, the respondents who had higher level of traditional familism showed a higher preference for direct economic service (supportive service) than for other types of service in child care. And the less traditional their attitudes towards marriage and child-rearing, the more likely they are to prefer flexible child care services and programs to other types of child care services. These results implied that the family value was partly influential to family policy. However, it is worthy to note that the family value was related to family policy preference rather than to family policy needs. In other words, traditional family value appeared to influence the types of family policy rather than the level of needs for family policy.