PURPOSES : To prevent an increasing number of drowsiness-related accidents, considering driver fatigue is necessary, which is the main cause of drowsiness accidents. The purpose of this study is to propose a methodology for selecting drowsiness hotspots using continuous driving time, a variable that quantifies driver fatigue. METHODS : An analysis was conducted by dividing driver fatigue, which changes according to time and space, into temporal and spatiotemporal scenarios. The analysis technique derived four evaluation indicators (precision, recall, accuracy, and F1 score) using a random forest classification model that is effective for processing large amounts of data. RESULTS : Both the temporal and spatiotemporal scenarios performed better in models that reflected the characteristics of road sections with changes in time and space. Comparing the two scenarios, it was found that the spatiotemporal scenario showed a difference in precision of approximately 10% compared with the temporal scenarios. In addition, [Model 2-2] of the spatiotemporal scenario showed the best predictive power by assessing the model’s accuracy via a comparison of (1-recall) and precision. This shows better performance in predicting drowsy accidents by considering changes in time and space together rather than constructing only temporal changes. CONCLUSIONS : To classify hotspots of drowsiness, spatiotemporal factors must be considered. However, it is possible to develop a methodology with better performance if data on individuals driving vehicles can be collected.

PURPOSES : Speed management is essential for enhancing children’s safety in school zones. The objectives of this study are to analyze how digital-based school zone signs and newly proposed signage for increasing visibility influence speed reductions and how the new system facilitates drivers obeying the speed limits. METHODS : A before/after analysis technique with comparison groups (widely used to evaluate safety effects) was employed. To effectively capture the safety effects of the new system, two significant measures were selected as the measures of effectiveness: the rates of change in space mean speeds and speed limit compliance. RESULTS : With three target sites and three comparison sites, the mean space speeds after installing the new systems were found to be slightly reduced for all target sites (the reduction rates of the space mean speed were found to be 5% for site A, 1% for site B, and 6% for site C). The lack of a constant tendency in speed reduction effects at all sites might be owing to the fact that the speed data collection was conducted before the driver's system adaptation was sufficiently performed. Regarding the speed limit compliance rate, significant increases were observed at two sites (10% for site A and 51% for site C), but site B did not show an increasing effect. The reason for the absence of this effect is that the installation of crosswalks and speed bumps at the target site affected the driver's compliance with the speed limit. CONCLUSIONS : An insufficient amount of evaluation results was obtained for the new guidance system. However, the new guidance system method provides an alternative approach to improving children's safety, i.e., by inducing drivers to actively slow down in school zones.

PURPOSES: This study analyzed the differences in drivers’behaviors and car movements between drowsy driving conditions and normal driving. METHODS: This study analyzed behavior data from 32 participants and the related car movement data in a field test under drowsy driving and normal driving conditions. Acquired data were closed-eye time, distance between the test car and the left lane, distance between the test car and the right lane, driving speed, video clip of the driver’s face during driving, and so on. A total of 30 samples for drowsy driving and normal driving were selected once errors had been excluded. RESULTS: There were three factors that differed between drowsy driving and normal driving conditions: closed-eye time, distance between the test car and the left lane, and distance between the test car and the right lane. These results were significant at the 0.05 level. CONCLUSIONS : This study shows that there are three factors that vary significantly between drowsy driving and normal driving conditions that can be useful for detecting drowsy driving. Future studies should be designed with these results in mind, further considering, age, type of road, study site, and so on.

목적: 시중에 판매되고 있는 콘택트렌즈는 착용기간에 따라 1DAY, 3DAY, 2WEEK 등으로 구분되어 있다. 하지만 실제로 렌즈를 착용하는 소비자들은 이 기간을 준수하지 않은 경우가 많다. 이에 본 실험은 렌즈의 권장 착용기간보다 초과 착용 시, 눈에 어떠한 영향을 미칠 수 있는지 알아보고자 하였다. 방법: 실험대상은 20~25세의 콘택트렌즈를 착용하는 젊은 성인 15명으로 안질환 및 안구 건조증이 없고, 난시값이 C-0.75D 이하로 제한하였다. 피실험자의 우안(A사, 1DAY 렌즈) 과 좌안(B사, 3DAY 렌즈)에 다른 종류의 렌즈를 착용 후 경과 시간에 따라 TBUT 검사, 쉬르머 검사, 눈부심 검사, 설문조사를 실시하였고, 하루 8시간 착용을 기준으로 1일차부터 3 일차까지 측정하였다. 위 4가지 항목의 기간 별 변화를 비교 하였다. 결과: TBUT 검사에서 A사 1DAY렌즈의 눈물층이 깨지는 시간은 1일차에서 3일차까지 평균 4.64±0.75초가 감소하였으며, B사 3DAY렌즈는 평균 3.49±0.61초 감소하였다. 쉬르머 검사에서는 A사 1DAY렌즈가 눈물량이 3일간 평균 10.8±1.67mm가 감소하였으며, B사 3DAY렌즈는 평균 2.06±0.35mm 감소하였다. C-quant 검사에서는 stray light 평균값이 A사 1DAY 렌즈는 1.01±0.10, 1.09±0.17, 1.10±0.18로 약 0.09 증가했으며, B사 3DAY렌즈는 1.08±0.09, 1.07±0.09, 1.01±0.13로 0.07 감소하였다. 3일 차에 콘택트렌즈의 착용 감을 묻는 설문조사에서 피실험자 15명 중 53%인 8명이 A사의 1DAY렌즈에 대해 불편감 을 느낀다고 했으며, 13%인 2명이 B사의 3DAY렌즈에 대해 불편함을 느낀다고 답변했다. 27%인 4명은 양안이 모두 불편하다고 응답하였으며, 양안 모두 불편함을 느끼지 않는 피실험자는 1명이었다. 결론: 1DAY 렌즈는 하루 착용 시 눈물막 안정성, 눈물량 생성정도가 3DAY 렌즈와 비교했 을 때 우수했으며, 하루 이상 착용했을 시 눈물량, stray light 값이 모두 상대적으로 감소하였다. 3DAY 렌즈는 하루 착용 시 눈물층이 깨지는 시간이 짧고, 눈물량이 1DAY 렌즈에 비해 적었으나, 시간이 경과함에 따라 나타나는 감소폭이 상대적으로 적게 나타났다. 1DAY 렌즈를 8시간 이상 착용 시 자각적으로 불편함을 겪을 수 있다. 따라서 콘택트렌즈 착용시 간이 8시간 이하일 경우 1DAY 렌즈를 권장하며, 그 이상 렌즈를 착용할 경우 목적에 따라 3DAY렌즈 혹은 그 이상 기간의 렌즈를 착용하는 것이 필요한 것으로 사료된다.

The government expands its investment on R&D programs for economic growth, thus there is growing attention on the result of R&D Programs. This study proposes more improved measuring method for efficiency when the number of R&D programs is not enough to be for measuring efficiency analysis. It provides more various application method of factors on efficiency analysis. This study analyzes the influence of each input factor on efficiency by using partial efficiency concept. And it also determines input factors in similar influence throughout Spearman correlation coefficient. Finally, it suggests new method to improve discriminatory power of efficiency analysis by determining representative factors. Also, the proposed method can be practiced not only for national R&D programs, but also for other fields of research.

The government expands its investment on R&D programs for economic growth, thus there are growing attention on the result of R&D programs. However, our existing research is in the circumstance of only measuring efficiency, but not reflecting unique characteristics of R&D programs. In this study, it provides more developed method for efficiency analysis in national R&D programs by using partial efficiency concept and measuring influence of input factors. It analyzes the influence of each input factor on efficiency by using partial efficiency concept. And it also determines input factors in similar influence throughout Spearman correlation coefficient. Finally, it suggests new method to improve discriminatory power of efficiency analysis by determining representative factors.

요즘 기존 장르 간의 융합을 통해 새로운 장르의 게임 개발이 계속되고 있으며, 이처럼 새롭게 융합된 장르의 게임이 세계적으로 인기를 끌고 있다. 이러한 추세에 따라 보다 효과적인 장르 융합을 위하여 기존 장르들의 특징적인 콘텐츠를 분석하는 것은 의미 있는 일이라고 할 수있다. 본 논문에서는 디지털 게임의 한 장르인 생존 게임 장르에서, 게임의 주요 목표이자 핵심이 되는 생존 콘텐츠에 대한 분석을 위해 대표적인 생존 게임을 선정하여 공통점과 차별화된특징들을 알아보고자 한다. 분석 기법으로는 MDA 프레임워크를 이용하여 생존 게임의 콘텐츠를 중심으로 게임 메커닉과 게임 다이내믹 구성 요소에 관하여 살펴보았다

인간 제대혈 세포는 조혈모세포, 중간엽 줄기세포와내피전구세포를 풍부하게 포함하고 있다. 인간 제대혈 속의 중간엽 줄기세포는 조혈모세포와는 달리 다능성 줄기세포이며 신경세포로 분화할 수 있는 잠재성을 가지고 있다. 본 연구에서는 세포배양을 통해 제대혈의 중간엽 줄기세포를 신경세포와 콜린성 신경세포로 분화를 유도하였다. 중간엽 줄기세포를 신경세포로 분화시키기 위해 배양액에 dimethyl sulphoxide(DMSO)와 butylated hydroxyani