• KDI Journal of Economic Policy
• /
• v.34 no.1
• /
• pp.135-168
• /
• 2012

This study analyzes ways to detect protest responses (hereafter, PR zero-bid) in the contingent valuation method (CVM). In order to distinguish PR zero-bids from true zero-bids (non-PR zero bids), this study adopts the concept of the implicit willingness to pay employing the Hicksian compensating surplus and the Taylor's 1st order approximation. When a respondent proposes a zero-bid (i.e., WTP=0) and chooses a PR filtering item to indicate that her implicit WTP is not necessary zero, her response is identified as a PR zero bid. PR filtering items falling into the PR zero bids category include the uncertainty of information, distrust in the government and project achievement, disagreement to project plans, discontent with the fairness of public works and their payment method and animosity against the CVM itself. The empirical analysis shows that PR zero bids take place systematically in particular respondent groups: respondents who have never used similar facilities before nor plans to use the facility provided by the public project, the employed, and low income groups. In conclusion, the study suggests that a CVM questionnaire needs to be designed carefully to minimize problems associated with PR zero bids and the potential risks of having sample selection bias should be concerned.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.2
• /
• pp.315-325
• /
• 2016

Thanks to the advantages of low cost and quick results, public opinion polls on election in Korea have been generally conducted by telephone survey, even though it has critical disadvantage of low response rate. In public opinion polls on election in Korea, the general method to handle nonresponses is adjusting the survey weight to estimate parameters. This study first drives mathematical expression of estimator and its bias with variance estimators with/without nonresponses in election polls in Korea. We also investigates the nonresponse rate of telephone survey on 2012 Korea presidential election. The average response rate was barely about 14.4%. In addition, we conducted a survey in April 2014 on the respondents's attitude toward telephone surveys. In the survey, the first reason for which respondents do not answer on public opinion polls on election was "feel bothered". And the aged 20s group, the most low response group, also gave the same answer. We here suggest that survey researchers motivate survey respondents, specially younger group, to participate surveys and find methods boosting response rate such as giving incentive.

• Korea journal of population studies
• /
• v.21 no.1
• /
• pp.162-183
• /
• 1998

This study examines the sampling bias that may have resulted from the large number of missing observations. Despite well-designed and reliable sampling procedures, the observed sample values in DSFH(Demographic Survey on Changes in Family and Household Structure, Japan) included many missing observations. The head administerd survey method of DSFH resulted in a large number of missing observations regarding characteristics of elderly non-head parents and their children. In addition, the response probability of a particular item in DSFH significantly differs by characteristics of elderly parents and their children. Furthermore, missing observations of many items occurred simultaneously. This complex pattern of missing observations critically limits the ability to produce an unbiased analysis. First, the large number of missing observations is likely to cause a misleading estimate of the standard error. Even worse, the possible dependency of missing observations on their latent values is likely to produce biased estimates of covariates. Two models are employed to solve the possible inference biases. First, EM algorithm is used to infer the missing values based on the knowledge of the association between the observed values and other covariates. Second, a selection model was employed given the suspicion that the probability of missing observations of proximity depends on its unobserved outcome.

• Proceedings of the Korea Contents Association Conference
• /
• 2011.05a
• /
• pp.245-246
• /
• 2011

본 연구의 목적은 스크린골프장 이용고객의 라이프스타일이 선택속성과 고객만족 및 재구매행동과의 인과관계를 규명하고자 하는 것이다. 본 연구의 연구대상은 2010년 3월 1일부터 2010년4월 30일까지 약 2개월간 부산 경남지역에 소재하고 있는 스크린골프장 10곳의 이용고객을 모집단으로 선정하였으며, 한 곳당 40부씩 총 400부를 직접 업체를 방문하여 배포하고 최종 332명을 표집하였으며, 표본 추출방법은 편의표본추출법을 사용하였고 설문에 대한 응답은 자기평가기입법을 채택하였다. 이들 설문지 중 신뢰성이 떨어진다고 판단되는 42명의 설문지를 제외하고 총 290명을 유효 표본으로 선정하여 본 연구의 자료로 이용하였다. 본 연구에서는 SPSS Window 12.0 통계 패키지를 이용하여 요인분석과 신뢰도분석, 빈도 분석, 회귀분석을 실시하였다. 연구결과를 보면 다음과 같다. 첫째, 스크린골프장 이용고객의 라이프스타일이 선택속성에 유의한 영향을 미치는 것으로 나타났다. 둘째, 스크린골프장 이용고객의 선택속성은 고객만족에 유의한 영향을 미치는 것으로 나타났다. 셋째, 스크린골프장 이용고객의 선택속성은 재구매행동에 유의한 영향을 미치는 것으로 나타났다.

• Communications for Statistical Applications and Methods
• /
• v.19 no.3
• /
• pp.345-358
• /
• 2012

In a parametric sample selection model, the distribution assumption is critical to obtain consistent estimates. Conventionally, the normality assumption has been adopted for both error terms in selection and main equations of the model. The normality assumption, however, may excessively restrict the true underlying distribution of the model. This study introduces the $S_U$-normal distribution into the error distribution of a sample selection model. The $S_U$-normal distribution can accommodate a wide range of skewness and kurtosis compared to the normal distribution. It also includes the normal distribution as a limiting distribution. Moreover, the $S_U$-normal distribution can be easily extended to multivariate dimensions. We provide the log-likelihood function and expected value formula based on a bivariate $S_U$-normal distribution in a sample selection model. The results of simulations indicate the $S_U$-normal model outperforms the normal model for the consistency of estimators. As an empirical application, we provide the sample selection model for car ownership and a car expense relationship.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.730-738
• /
• 2010

In the development of railroad station area, there are many factors about business management, but the interest of railroad users is an important factor as customer satisfaction. It is necessary to have the quality estimation of railroad service, and important factors of service as customer satisfaction aspects can be supply, reliability, convenience, and safety. In this study, primary factors are deduced in the efficiency aspects of railroad station facilities from analyzing relative importance index using AHP(Analytic Hierarchy Process) methods. The most high rank important factor is railroad station user facilities, and the AHP importance index of passenger facilities and elevator facilities for KORAIL personnel and facility users is index. The third of KORAIL personnel is movement facilities, but facility users index is sanitation. And the low important factors of KORAIL personnel and facility users are shown as the platform in passenger facilities, the rest facilities in waiting room, the escalator in going up and coming down facilities, the escalator in movement facilities, the raised letters block in guide facilities, and the parking lot in subsidiary facilities.

• Culinary science and hospitality research
• /
• v.19 no.5
• /
• pp.296-311
• /
• 2013

This study aims to show basic data to build suitable marketing strategies for consumers by determining the motivation and selection attributes of HMR according to their lifestyles. A survey was conducted from March 1st to March 30th, 2013, and total 362 out of 450 copies of questionnaire were used for analysis. The results are as follows. First, it showed that the pursuit of health in lifestyle had a significant effect on usefulness and economical efficiency. Next, the pursuit of health was analyzed not to have a significant effect on HMR quality and convenience. Third, usefulness and economical efficiency in the category of motives for purchasing HMR didn't have any significant effect on repurchase intention. Finally, HMR quality and convenience in the selection attributes of HMR had a significant effect on repurchase intention.

• Tunnel and Underground Space
• /
• v.8 no.3
• /
• pp.249-256
• /
• 1998

Pocheon, Keochang and Sangju granite samples of different granularity and mineralogical composition were thermally treated at pre-determined temperature of $600^{\circ}C$. Thermally-induced microcracks were characterized using an optical microscopy and their effects on the deformation behavior of thermally cycled samples were studied performing compressive mechanical tests. Optical observations shows that by $600^{\circ}C$ nearlly all crystal boundaries open and the new intracrystalline cracks form in the more grains. The intracrystalline cracks are most pronounced at thermally treated Pocheon and Keochang granite samples. Results from mechanical tests represents negative lateral strains, which give negative Poisson's ratios. It is the most probable that negative lateral strains are produced by residual stresses induced during cooling.

• 한국HCI학회:학술대회논문집
• /
• 2006.02b
• /
• pp.424-434
• /
• 2006

최근 다양한 디지털 컨텐츠를 온라인의 서버와 오프라인의 개인 컴퓨터 혹은 소형 정보기기에서 공유하여 사용이 가능하도록 도와주는 시스템과 서비스들이 출현하고 있다. 이와 같은 시스템은 사용자가 언제, 어느 곳에 있더라도 원하는 디지털 컨텐츠에 접근할 수 있도록 도와준다는 장점을 갖고 있으며, 또한 해당 디지털 컨텐츠의 저작권을 보호할 수 있다는 부가적인 이점을 제공한다. 그러나 이들 시스템은 도입 초기에 대부분의 개발자들이 저지르기 쉬운 기능 중심적 사고에 치우친 시스템인 경우가 많다. 이들 기능 중심적인 시스템은 사용자가 해당 시스템을 어떻게 인지할 것인지에 대한 이해가 부족한 한계를 갖고 있으며, 이는 결국 시스템의 사용 편의성에 영향을 미칠 수 있다. 본 연구에서는 디지털 컨텐츠를 온라인과 오프라인에서 공유하여 사용할 수 있는 시스템의 구조적 메타포로 공간을 선택하였다. 사용자의 시스템 환경으로서 온라인과 오프라인, 그리고 사용자가 디지털 컨텐츠를 이용하여 수행하는 과업으로서 관리/저장과 사용으로 시스템의 구조를 구분하였으며, 이상의 구분에 따라 공간의 메타포를 이용하여 시스템을 디자인하였다. 이와 같이 구분한 시스템의 공간에 따라 사용자가 시스템에 대하여 갖는 관여도와 동기를 측정하였으며, 관여도의 수준과 동기의 차원에 따라 사용 편의성을 높일 수 있는 디자인 요소로서 시스템을 구현하고 있는 색상들 사이의 대비 수준과 색상의 색조 차원을 규명하고자 한다.

• Information and Communications Magazine
• /
• v.29 no.9
• /
• pp.30-37
• /
• 2012

과거 단순한 이동수단이었던 자동차는 다양한 안전과 편의적 서비스를 제공하게 되면서 다양한 활동이 수행되는 생활의 한 공간으로 자리매김하고 있다. 이에 따라 차량을 선택하는데 있어 소비자 취향에 맞는 다양한 부가 서비스를 제공하는지가 중요한 요소로 작용함에 따라 자동차 산업에 IT 기술의 접목에 대한 필요성이 대두되었다. 이러한 흐름에 따라 자동차 IT 융합이 가속화되고 있으며, 편의성, 안전성, 편리성을 위해서 차량 내에 많은 ECU의 사용이 필수적으로 요구되고 있다. 이러한 자동차의 부품에 소프트웨어가 탑재됨에 따라 공통적으로 사용되는 모듈에 대하여 재사용성, 부품 호환성 등의 요구가 생겨나게 되었고, 이를 해결하고자 하는 움직임이 차량 SW 플랫폼 표준화를 통해서 활발하게 이루어지고 있다. 본 고에서는 자동차 서비스 개발을 위한 대표적인 차량 전장용 SW 플랫폼인 AUTOSAR 플랫폼과 차량 내 헤드유닛을 통해 멀티미디어 및 텔레매틱스 서비스를 제공하는 차량용 인포테인먼트 시스템을 위한 표준 플랫폼인 GENIVI 플랫폼에 대하여 살펴보고자 한다.