• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.22 no.6
• /
• pp.77-91
• /
• 2023

Recently, there has been a worldwide increase in research and development on automated vehicles for commercialization. It is expected that the use of level 3 autonomous vehicles on continuous-flow roads will be introduced and will increase. Consequently, various studies have been conducted to investigate the impact of mixed traffic flow with automated vehicles based on the market penetration rate (MPR). However, these studies have been conducted independently, and the results have shown different trends. Therefore, this study attempted a quantitative analysis of the impact of automated vehicles on mixed traffic flow on uninterrupted roads through a meta-analysis. The results showed that the effect size estimated from an MPR of 75% or higher was statistically significant.

• The Korean Journal of Applied Statistics
• /
• v.21 no.3
• /
• pp.455-468
• /
• 2008

Based on the huge baseball game records, the steal plays an important role to affect the result of games. For the research about success or failure of the steal in baseball games, logistic regression models are developed based on 2007 Korean professional baseball games. The analyses of logistic regression models are compared of those of the discriminant models. It is found that the performance of the logistic regression analysis is more efficient than that of the discriminant analysis. Also, we consider an alternative logistic regression model based on categorical data which are transformed from uneasy obtainable continuous data.

• Economic and Environmental Geology
• /
• v.28 no.3
• /
• pp.271-277
• /
• 1995

The geological information analysis based on spatial statistical techniques have been studied in relation to mineral exploration. The applicability of outlier detection using moving-window statistics and directional cross-variography analysis have been verified by using geochemical data sets surveyed in the Taebaek area for mineral exploration. The directional variogram analysis has been basically known as a geostatistical method for spatial continuity measures. In this study, the application of this proposed method was extended to measure spatial correlation or similarity problems between two geochemical elements. For the appraisal of the usefulness of this scheme, five kinds of variogram functions were computed for original data and revised data, obtained by removing outliers detected by moving-window statistics and the results were compared. It is concluded that these advanced spatial statistical methods at the interpretation stage of spatial similarity provide us with valuable quantitative results as decision-supporting information for regional mineral exploration task.

• The Korean Journal of Applied Statistics
• /
• v.33 no.2
• /
• pp.123-136
• /
• 2020

It is common to encounter correlated multiple outcomes measured on the same subject in various research fields. In developmental toxicity studies, presence of malformed pups and fetal weight are measured on the pregnant dams exposed to different levels of a toxic substance. Joint analysis of such two outcomes can result in more efficient inferences than separate models for each outcome. Most methods for joint modeling assume a normal distribution as random effects. However, in developmental toxicity studies, the response distributions may change irregularly in location and shape as the level of toxic substance changes, which may not be captured by a normal random effects model. Motivated by applications in developmental toxicity studies, we propose a Bayesian joint model for binary and continuous outcomes. In our model, we incorporate a skewed logit model for the binary outcome to allow the response distributions to have flexibly in both symmetric and asymmetric shapes on the toxic levels. We apply our proposed method to data from a developmental toxicity study of diethylhexyl phthalate.

• The Korean Journal of Applied Statistics
• /
• v.35 no.3
• /
• pp.357-370
• /
• 2022

In this paper, Tobit and Heckit models are introduced. These models have been used for analyzing censored data. Censoring occurs at a specific point and a large number of observations are distributed with a positive probability at a certain point. Censoring can occur due to observing limitation or exogenous variables. Tobit and Heckit models are used to correct sample selection bias, which can occur when an ordinary linear regression model is fitted to censored data. However, the difference between the two models is not clearly accounted for; hence, they have often been used interchangeably. Therefore, the suitability of the models was validated through simulated data, and demonstrated through real data. As the result, it was confirmed that both Tobit and Heckit models are well-fitted to the data censored due to observing limitation, although Tobit model was fitted parsimoniously. In contrast, only Heckit model is well-fitted to the data censored due to exogenous variables.

• Journal of Wetlands Research
• /
• v.19 no.1
• /
• pp.132-143
• /
• 2017

It is essential to obtain periodic sediment discharge data in a river in order to minimize problems that may arise from the erosion, transport, and deposition of sediment. However, it is difficult to estimate sediment discharge by the sediment discharge measurement plan in Korea at present, and empirical fomulas or numerical models are used to replace them. This paper has applied the K-DRUM model, a grid-based rainfall-runoff-sediment model, to estimate sediment discharge and ensure the continuity of the data in the watershed. Discharge and sediment load in 17 watersheds were estimated and the applicability of the model was analyzed through comparisons with measured data. For quantitative evaluation, NSE, PBIAS and RSR items were used, and discharge results reflected the tendency of rainfall and showed high statistical value. In case of sediment discharge, the soil erosion process of the watershed is physically well reflected. When the calibration was performed using the measure data, the applicability seems to be excellent in estimating the continuous sediment discharge data in the real watershed.

• Journal of Korean Society of Transportation
• /
• v.35 no.5
• /
• pp.423-433
• /
• 2017

During recent 5 years, it was recorded that 20% of total accident frequency and 30% of total number of death have been occurred due to drowsy driving. Drowsy driving accident is result from the loss of driving ability due to driver's accumulated fatigue. Continuous driving time can be measured as a surrogate variable to quantify the level of fatigue. The main purpose of this research is to investigate statistical correlation between the proportion of continuous driving vehicle (more than 2 hours) and the number of drowsy accidents. To carry this out, continuous driving time was measured using GPS route-guidance trajectory data. Also, accident frequency, traffic volume and segment length were collected to estimate safety performance function (SPF) for Jungbunearuk expressway in Korea. Through various types of estimated SPFs, statistical correlation was analyzed based on estimated statistical indices. This research can provide theoretical background for enforcement to regulate commercial vehicle driver's continuous driving time. In addition, throughout the trajectory data expansion, it is expected that strategy for anti-drowsy driving facilities installation can be established based on the suggested methodology.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.308-308
• /
• 2019

지구상 해양, 대기 및 대륙 상호간의 연속적인 물의 거동을 나타내는 물의 순환의 주요 과정 중 하나인 유량 자료는 경년부터 수십년간의 다양한 기상학적 변동성을 내포하며 해당 지역의 수문기상학적 특성을 반영한다. 이러한 기상학적 변동성 중에서 비교적 긴 시간 주기를 나타내는 저주파 진동은 전지구적 기후변화의 장기적 영향을 나타내며 해수면 상승, 홍수 또는 가뭄과 같은 극한 수문사상을 나타내는 매우 주요한 지표로 활용되고 있지만 관측된 수문 시계열의 짧은 자료길이로 인하여 통계적 분석의 신뢰성에 한계를 보여왔다. 따라서 과거 수문 시계열의 확장으로 인하여 부재의 영역으로 남아있던 자료 기간의 한계가 보완되면 보다 정확하고 신뢰도 있는 분석이 가능할 것이다. 나무나이테를 활용한 고기후 복원 등의 연구가 증가하고 있지만 공학 분야에서 이를 실제로 활용한 연구는 아직 미비하다. 따라서 본 연구에서는 과거 기후의 정보를 바탕으로 복원된 수문 시계열을 활용하여 수문 시계열에 내재된 장기 기후 변동성을 통계적으로 분석하기 위한 문헌들을 조사하고, 장기적인 시간 흐름에 내재된 잠재적인 경향 및 변동성을 통계적 분석을 파악하고자 한다. 이를 위해 주어진 수문 시계열에 내재된 저주파 신호을 추출하기 위한 경험적 모드분해법을 활용하여 수문 자료에 내재된 장기 변동성을 추출하였으며, 산업화 이전부터 연장된 수문 시계열의 공학적 활용성을 분석하고자 한다.

• Communications for Statistical Applications and Methods
• /
• v.19 no.3
• /
• pp.381-393
• /
• 2012

This study is to understand the logistic area effect for the satisfaction of military service; service people work the unit of Marine Corps which is close or far away from North Korea and infantry people from the structural equation models based on the component based method(PLS). From the result, we note that the trustworthy and suitability of supply are the most important factors in their of military service satisfaction for Marine Corps.

• 한국HCI학회:학술대회논문집
• /
• 2007.02a
• /
• pp.143-149
• /
• 2007

영상은 동적인 시각 이미지와 청각의 결합에 의해 감성적인 반응을 유도한다. 다양한 영상 기법을 통하여 감성적 반응의 극대화를 추구하는 영화는 영상의 시청각적 요소들을 감성의 관점에서 효과적으로 설계하는데 본보기가 된다. 그러나, 제품의 설계속성들에 대한 감성적 평가결과를 모형화하는 감성공학적 관점에서 볼 때 영화는 시청각적 자극의 수준이 극히 다양하고 동적인 경험재로 모형화의 어려움이 있다. 본 연구에서는 영화의 감성 모형을 구축하기 위한 사전연구의 단계로 영화에서의 시청각적 요인들을 문헌조사를 통해 수집, 정리, 선별하고 이러한 시청각적 요인들 중에 영화를 관람하는 관객의 감성적, 인지적 반응에 영향을 주는 유효한 요인들을 객관적이고 체계적으로 탐색하고자 하였다. 이를 위해, 감성 및 인지적 반응의 변화를 생체신호를 통해 측정하는 한편, 생체신호의 측정 시 사용된 영화의 시청각적 자극요인을 Video/Audio Processing방법에 의해 연속적인 수치로 정량화하였다. 생체신호와 정량화된 시청각적 자극요인을 동기화하고 통계적으로 분석함으로써, 생체신호의 반응과 시청각적 자극요인과의 인과관계를 통계적으로 신뢰성있는 수준에서 검증하고자 하였다. 생체신호를 종속변수로, 시청각적 자극요인을 독립변수로 하는 896개의 부분선형회귀모형(Partial Linear Regression Model)들 중 통계적으로 유의한 선형관계에 있는 경우의 빈도분석에 의하면, 시각적 요인들 중에는 밝기(Brightness), 대비(Contrast), 색상(Color), 움직임(Motion), 장면전환속도(Shot change Rate), 주요대상의 상대적 크기가, 청각적 요인들 중에는 Peak주파수, Peak주파수의 음량, 평균음량, 소음비(Sound-to-Noise Ratio)가 생체신호의 변화에 통계적으로 유의한 영향을 주는 것으로 나타났다. 이는, 위의 시청각적 자극 요인들은 특히 관객의 감성 및 인지적인 반응에 유의한 영향을 주는 요소로 작용할 수 있음을 시사하고 있다. 이를 토대로, 위의 시청각적 자극 요인들이 가지는 다양한 조합들을 설명변수로 하는 통계적인 영화의 감성 모형을 구축할 수 있을 것으로 기대한다.