겨울철 국내 도로 결빙으로 인한 교통사고가 증가하는 추세를 보이고 있으며 2018년~2022년까지 총 4,609건의 결빙 교통사고가 발 생하였다. 결빙 교통사고의 치사율은 2.3으로 일반적인 교통사고와 비교하여 높은 치사율을 보이며 최근 5년(2018~2022)동안 결빙 교 통사고로 인하여 107명이 사망자와 7,728명의 부상자가 발생하였다. 현재 국토교통부에서 제시한 결빙 취약구간 평가기준표에 따라 결 빙 위험 구간을 지정하고 있으나, 해당 기준은 결빙의 주요 요인으로 고려되는 기상조건을 충분히 반영하지 못하고 있다. 도로 결빙은 노면온도가 0℃ 이하이며 노면에 수분이 공급될 때 형성되며 기온, 구름량, 풍속, 풍향, 상대습도, 강수량 등의 기상인자들이 복합적으 로 작용하여 결빙이 발생한다는 점을 고려하였을 때, 기상 특성은 도로 결빙의 주요 인자로 판단된다. 따라서 국내 결빙 취약구간 평 가기준의 개선이 필요하며 본 연구의 목적은 국내 결빙 교통사고 데이터를 분석하고 결빙이 형성되는 기상 조건을 구체화하는 것이다. 분석을 위한 데이터로 2018년~2022년까지 5년동안 발생한 결빙사고 사례와 기상청 방재기상관측소(AWS)에서 제공하는 기상 데이터 를 적용하였다. 이후, 박스도표, 확률밀도함수 등의 통계분석을 적용하여 결빙 형성 기상 조건을 구체화하였다. 이를 통하여 기존 결빙 취약구간 평가기준의 기상학적 개선 방향성을 제시할 수 있으며 더 나아가 도로 결빙 예측 로직 개발을 기대할 수 있다.

PURPOSES : LED based Variable Message Signs(VMS) have been widely used to inform safety messages to the drivers in advance. Legibility Distance of VMS is the most important factor to provide the safety messages to drivers in timely and effective way. However, current National Standards on legibility distance design considers letter size only even there is a difficulty to read the signs at adverse weather conditions such as heavy fog. So, this study examined the legibility issue under fog by evaluating the legibility distance with two design factors such as letter size and luminance. METHODS : Two foggy weather conditions, intermediate and heavy fog, were simulated at real-road-scale Proving Ground. Legibility distance at daytime and nighttime was evaluated by test subjects. Subjects were asked to fill the legible distance on the test sheet and statistical significant was analysed at the lab. RESULTS : The legibility distance(LD) under fog was observed only 22 to 41% of LD observed under normal weather condition at daytime, and 26 to 45% at nighttime condition. Study results showed a consistent increase in LD with higher luminance even at same letter size and vice versa conditions, However, statically significant difference between groups was only revealed when both letter size and luminance level increased conditions. In order to apply the test results in terms of engineering benefits, LD results from significantly different groups was evaluated with relative to Stopping Sight Distance(SSD) within conceptual frame suggested in this study. CONCLUSIONS : From the study results, current National Standard on legibility distance design needs to consider letter size and luminance simultaneously to response the legibility issue in adverse weather conditions.

항공기는 대표적인 인간-기계시스템이다. 인간의 조작과 기계의 작동 완료 시점 사이에는 기계가 작동되기 시작하 는 시간과 기계에 힘이 전달되기 시작하여 완료되는 시간 등의 지연이 발생하며 항공기 조종은 시스템의 지연을 예 측한 타이밍 작업을 통해 이루어진다. 시간지각은 타이밍 작업의 중요한 요소이며, 높은 각성작용과 관련된 불안에 영향을 받는 것으로 알려져 있다. 본 연구는 가상현실 환경에서 현직 조종사를 대상으로 기상, 비행 및 시간 조건이 조종사에게 발생하는 불안과 시간지각에 미치는 영향을 검증하였다. 기상조건은 시계비행 기상 상황과 악기상 상황 으로 구분하였고 비행 및 시간 조건을 달리하여 실험 1, 2를 실시하였다. 실험 1은 비교적 운동량의 변화가 적고 지연이 적은 제자리비행과 수평비행 상황에서 조종간에 추가된 버튼을 사용하여 시간지각을 측정하였다. 실험 2는 운동량의 변화가 많고 지연이 많이 발생하는 이륙상황에서 조종간만을 사용하게 하여 자연스럽게 헬리콥터를 이륙 시키는 과정에서 시간지각을 측정하였다. 실험결과 악기상 상황에서 불안과 심박수가 증가하는 것으로 나타났으며, 특히 실험 1, 2의 모든 비행조건 중 불안이 증가한 상황에서 시간을 과대 추정하는 것으로 나타났다. 이 결과는 불안 의 영향으로 시간을 과대 추정하여 타이밍 작업을 실패할 수 있으며, 이로 인해 조종에 어려움을 겪고 사고로 연결될 가능성이 있음을 시사한다.

과수재배에 있어 기상조건은 수량과 품질에 직간접적으로 영향을 미치는 중요한 인자이다. 과거와 달리 요즘 3~4월 최저기온 변동의 폭이 넓어 꽃이 일찍 피는 과종에서는 화기의 동해로 인한 착과불량 피해가 자주 발생하고 있다. 또한 여름 철 폭염도 빈번히 발생하고 있으며, 올해처럼 구름 끼고 비가 잦은 경우 과실 생장과 품질에 부정적인 영향을 미칠 확률이 매우 높다. 본 연구는 2015년부터 2017년까지 3년간 키위 재배지 2곳에서 4월부터 10월까지 발아 후 생육기 동안 온도변 화와 광합성유효광선(PAR)을 조사하였다. 또한 과실특성을 조사하여 연차간 기상조건의 차이가 과실품질에 미치는 영향을 조사하였다. 2016년, 2017년은 2015년에 비해 6월~9월 평균 기온이 약 1~2oC 높았으며, 특히 7~8월은 2oC 가량 높은 폭염현상을 나타냈다. 광합성유효광선(PAR) 조사량을 측정한 결과, 노지재배인 사천지역은 4월에서 8월까지는 2015~2017년 모두 평균 300 μmol PAR m-2 s-1 이상을 나타냈으나 2015년을 제외한 2016년, 2017년 9~10월에는 300 μmol PAR m-2 s-1 미만을 나타냈다. 비가림 재배인 보성은 생육기 전반에 걸쳐 300 μmol PAR m-2 s-1 구간이였으며, 특히 9~10월은 2015~ 2017년 모두 300 μmol PAR m-2 s-1 미만을 나타냈다. 농촌진흥 청에서 육성된 신품종 ‘감록(Garmrok)’, ‘골드원(Goldone)’ 품종을 두 지역에서 재배, 수확한 결과 상대적으로 광합성유효 광선(PAR)량이 부족했던 보성에서 생산된 과실의 품질이 낮았다.

PURPOSES : In this study, the relationship between the types of road pavement markings and the visibility distance under adverse weather conditions was evaluated. METHODS : Rainy and foggy conditions at the weather proving ground were replicated in this study. The researchers recorded the visibility distance corresponding to each experiment scenario comprising the weather conditions and pavement marking types. RESULTS : Visibility distances under adverse weather conditions decreased more than those of normal weather conditions. Under rainy conditions, the average visibility distance across all pavement markings decreased by 33%. However, the average visibility distance across all pavement markings foggy conditions decreased by 46.8%. Based on the test results of the visibility distance, the speed reduction rates corresponding to the adverse and normal weather conditions, i.e., 24% and 36% speed reduction under rainy and foggy conditions, respectively, were established. CONCLUSIONS : This study validated the reduction in the visibility distance affected by weather conditions by applying actual road scale weather proving ground. In addition, speed reduction was recommended for safe driving under adverse weather conditions.

PURPOSES : In this study, the characteristics of fine particulate matter (PM2.5) concentrations under different weather conditions of different types of bus stops, such as enclosed-type and open-type bus stops, were analyzed using statistical methods. METHODS : Data was collected inside and outside an enclosed bus stop on sunny and rainy days to compare and analyze the characteristics of fine particulate matter concentration in the target bus stop. The probability distributions were estimated for each data point using the Anderson–Darling test. Based on the estimated probability distributions, probability density functions were computed, and the values were used to estimate and compare probability for each air quality index inside and outside the bus stop under different weather conditions RESULTS : For the results of descriptive statistics, the average concentrations of fine particulate matter inside and outside the bus stop were 42.296 and 35.482 μg/m3 on a sunny day and 40.831 and 39.321 μg/m3 on a rainy day, respectively. Results of the statistical method, obtained using the Anderson-Darling test, indicate that the probability of the air quality index inside the bus stop reaching high concentrations on a sunny day was "high" or "very high," compared to that outside the bus stop. However, on rainy days, the differences in fine particulate matter concentrations inside and outside the bus stops were difficult to identify based on statistical evidence. CONCLUSIONS : It was found that the open-type bus stop had an advantage of preventing fine particulate matter effects on sunny days, compared to the enclosed-type bus stops. Furthermore, there were slight differences in fine particulate matter concentrations inside and outside the bus stop on a rainy day because of atmospheric flow and stormwater.

PURPOSES : The purpose of this study is to analyze the impact of the level of the light-environment and the driver's visual ability on the change in the driver's perception of a forward curved section at night. The study also aims to identify factors that should be considered to ensure safety while entering curved sections of a road at night. METHODS : Data collected from a virtual driving experiment, conducted by the Korean Institute of Construction Technology (2017), were used. Logistic regression was applied to analyze the effects of changes in the light-environment factors (road surface luminance and glare) and the driver’s visual ability on a driver's perception of the road. Additionally, analysis of the moderated effect of visual ability on light-environment factors indicated that the difference in drivers’ visual abilities impact the influence of light-environment factors on their perception. A driver's ability to perceive, as a response variable, was categorized into 'failure' and 'success' by comparing the perceived distance and minimum reaction sight distance. Covariates were also defined. Road surface luminance levels were categorized into 'unlit road surface luminance' (luminance ≤ 0.1 nt) and 'lit road surface luminance' (luminance > 0.1 nt), based on 0.1 nt, which is the typical level observed on unlit roads. The glare level was categorized as 'with glare' and 'without glare' based on whether the glare was from a high-beam caused by an oncoming vehicle or not. The driver's visual ability level was categorized into 'low visual ability' (age ≥ 50) and 'high visual ability' (age ≤ 49), considering that after the age of 50, the drive’s visual ability sharply declines. RESULTS : The level of road surface luminance, glare, and driver's visual ability were analyzed to be significant factors that impact the driver's ability to perceive curved road sections at night. A driver's perception was found to reduce when the road surface luminance is very low, owing to the lack of road lighting ('unlit road luminance'), when glare is caused by oncoming vehicles ('with glare'), and if the driver's visual ability level is low owing to an older age ('low visual ability'). The driver's ability to perceive a curved section is most affected by the road surface luminance level. The effect is reduced in the order of glare occurrence and the driver's visual ability level. The visual ability was analyzed as a factor that impacts the intensity of the effect of change of the light-environment on the change of the driver's ability to perceive the road. The ability to perceive a curved section deteriorates significantly in 'low visual ability' drivers, aged 50 and above, compared to drivers with 'high visual ability,' under the age of 49, when the light-environment conditions are adverse with regard to the driver’s perception (road surface luminance: 'lit road surface luminance'→'unlit road surface luminance,' glare: 'without glare'→'with glare'). CONCLUSIONS : Supplementation, in terms of road lighting standards that can lead to improvements in the level of light-environment, should be considered first, rather than the implementation of restrictions on the right of movement, such as restricting the passage of low visual ability or aging drivers who are disadvantageous in terms of gaining good perception of the road at night. When establishing alternatives so that safety on roads at night is improved, it is necessary to consider improving drivers' perception by expanding road lighting installation. The road lighting criteria should be modified such that the glare caused by oncoming traffic, which is an influential factor in the linear change in perception, and the level of light-environment thereof are improved.

Adverse weather is a big challenge not only for the safety of drivers but the safety of Autonomous Vehicles (AV). The gap between human-driving and AV-driving in terms of adverse-weather-perception can be a new challenge for highway engineers. Solutions minimizing the gap need to be defined. By this, the smart road technologies can be specified and developed. The way how to define and quantify the gap is introduced in this presentation.

PURPOSES: This study develops various models that can estimate the pattern of road surface temperature changes using machine learning methods. METHODS : Both a thermal mapping system and weather forecast information were employed in order to collect data for developing the models. In previous studies, the authors defined road surface temperature data as a response, while vehicular ambient temperature, air temperature, and humidity were considered as predictors. In this research, two additional factors-road type and weather forecasts-were considered for the estimation of the road surface temperature change pattern. Finally, a total of six models for estimating the pattern of road surface temperature changes were developed using the MATLAB program, which provides the classification learner as a machine learning tool. RESULTS: Model 5 was considered the most superior owing to its high accuracy. It was seen that the accuracy of the model could increase when weather forecasts (e.g., Sky Status) were applied. A comparison between Models 4 and 5 showed that the influence of humidity on road surface temperature changes is negligible. CONCLUSIONS: Even though Models 4, 5, and 6 demonstrated the same performance in terms of average absolute error (AAE), Model 5 can be considered the optimal one from the point of view of accuracy.

This paper investigates minimum safe distances relative to a ship’s four cardinal sides, as perceived by Filipino navigators when encountering dangerous elements and in adverse weather conditions when maneuvering in and around harbors. It uses a descriptive research method in the form of a questionnaire survey for experienced Filipino navigators of various ranks. During the course of research, 71 responses were colleted and the resulting data is presented in graphical and tabulated forms. Statistical methods including Pearson-product moment correlations, Cronbach’s Alpha and ANOVA were used to identify internal associations, consistencies and significances, respectively. It has been proven that there are no significant differences in minimum safe distances relative to a ship’s four cardinal sides, whether maneuvering while approaching a port or within an inner harbor. This study has been deemed significant for training future navigators, managing traffic in fairways, and designing harbors and maneuvering areas in the approaches to ports, among other applications. This work can also be used as a preliminary study for comparison with the well known safe domains presently in use.

We investigated pollination and foraging activities of honeybee (Apis mellifera L.) and bumblebee (Bombus terrestris L.) during flowering season of the asian pear (Pyrus pyrifolia N.) under different weather conditions. There was no significant statistical difference about the pollination activities of two species. However, the pollination activities of bumblebee were more active than those of honeybee under low temperature and rainfall period. The activities of honeybee and bumblebee were more influenced by temperature than other factors (i.e. illumination and wind velocity). Honeybee was more sensitive to temperature and illumination than bumblebee. At low temperatures (<20℃) on cloudy days (<30,000 lux) with a certain wind velocity (>4.0 m/s), the pollination activity of the honeybee was lower twice than that of bumblebee.

Bumblebee, Bombus terrestris is widely used to pollinate various crops, especially tomato, in greenhouses. Mason bee, Osmia cornifrons, which is using as apple pollinator. Here we investigated characteristics on pollinating activity of B. terrestris and O. conifrons at different weather conditions in apple orchard. The foraging activity of O. conifrons was more sensitive than that of B. terrestris at weather conditions including temperature, illumination intensity and wind velocity. The pollinating activity of O. conifrons was very low than that of B. terrestris at a low temperature, cloudy, rainy and windy weather. Therefore, Our results indicated that B. terrestris was suitable for apple pollinator than O. conifrons, especially in low temperature and bad weather.

Bumblebee, Bombus terrestris is widely used to pollinate various crops, especially tomato, in greenhouses. Mason bee, Osmia cornifrons, which is using as apple pollinator. Here we investigated characteristics on pollinating activity of B. terrestris and O. conifrons at different weather conditions in apple orchard. The foraging activity of O. conifrons was more sensitive than that of B. terrestris at weather conditions including temperature, illumination intensity and wind velocity. The pollinating activity of O. conifrons was very low than that of B. terrestris at a low temperature, cloudy, rainy and windy weather. Therefore, Our results indicated that B. terrestris was suitable for apple pollinator than O. conifrons, especially in low temperature and bad weather.

노면표시에 도포된 굴절률 1.5 유리알은 야간 우천 시 효과적인 재귀반사를 수행하지 못하여 교통안전에 심각한 문제를 초래하고 있다. 이를 극복하기 위해 습윤상태에서 효과적 재귀반사를 수행하는 굴절률 2.4인 우천형 bead와 건조 시 최적의 재귀반사를 수행해 내는 굴절률 1.9 bead를 혼합한다. 그러나 고성능의 굴절률 1.9와 2.4 bead는 기존 1.5 유리알에 비해 상당한 고가이므로 전량 사용하기에는 상당한 비용이 소요된다. 따라서 현장 설치 시에는 서로 혼합하여 사용하는 것이 바람직하며, 최적 성능과 소요 비용을 고려한 적정 배합비율을 찾아내는 것이 중요하다. 본 연구에서는 다양한 비율로 혼합된 bead를 국내 고속도로의 길가장자리선에 설치하였을 때 발생되는 각각의 비용 및 편익에 따른 경제성 분석을 수행하였다. 분석 수행결과, 다양한 강수량 변화에도 높은 시인성을 유지하는 대안은 굴절률 2.4가 100% 구성된 차선으로 나타났으며, 경제성이 가장 높게 확보되는 대안은 굴절률 1.5가 80%, 2.4가 20%로 구성된 차선으로 B/C는 약 1.92 수준으로 도출되어 국내 고속도로 길가장자리선의 적용 시 가장 효과적인 대안인 것으로 확인되었다. 아울러 연구의 한계와 몇몇 장래 연구과제가 토의되었다.

능이 연구의 기초자료로 활용하고자 능이 발생과 관련되는 토양수분과 기상인자들을 조사 분석하였다. 1. 조사기간동안의 토양수분의 경향은 능이 발생지의 평균토양수분이 14.3%이고, 능이 비발생지의 평균토양수분은 16.4%로 능이 비발생지의 평균토양수분이 약 2.1% 높게 유지되고 있음을 알 수 있다. 이를 통하여 능이 균사의 생장 및 자실체 발생에 많은 수분이 필요하다고 판단된다. 또한 강수가 적어 토양수분이 극도로 낮아지면 오히려 경향이 역전되 는 현상을 확인할 수 있었다.또한 발생지와 비발생지의 토양수분 차이에 착안하여 본 연구를 위한 조사과정에서는 휴대 용 토양수분 측정장비(CS620, Campbell Scientific Inc.)로 발생지와 비발생지의 토양수분의 차이를 이용한 균사와 균 환의 위치파악이 가능하였으나 향후 추가적인 연구가 더욱 필요하다고 판단된다. 2. 능이 발생지의 평균지중온도는 16.8℃이고, 능이 비발생지의 평균지중온도는 16.5℃로 큰 차이는 없으나 발생지의 평 균지중온도가 높게 유지되는 경향을 보이고 있다. 이것은 능이 균사의 호흡열에 의한 온도상승으로 생각된다. 3. 대기온도와 지중온도의 영향에 있어서는 능이 원기의 발생과 자실체의 생장에는 일최고기온, 일최저기온과 일최저지온 이 영향을 미치고 있다고 판단되며, 같은 균근성 버섯인 송이의 경우와 유사한 경향을 보이고 있다. 4. 능이의 발생시기는 일반적으로 8월말∼9월초 능이 발생이 시작되어 10월 초순경에 종료되는 것으로 알려져 있다. 그 러나 2002년의 경우에는 최초 능이 발생시기가 8월 초로 빨라졌으며, 이것은 최근 계속되고 있는 기상이변과 엘리뇨 등 으로 인하여 기상이 고르지 못한데 기인하는 것으로 판단된다. 이와 같은 기상이변이 계속된다면 향후 능이나 송이의 발생시기의 예측에 많은 어려움이 따를 것으로 생각된다. 5. 능이도 송이의 경우와 유사한 고온장해의 피해를 입는 것으로 판단되며 일최고기온이 25℃ 이상, 일최저지온이 20℃ 이상으로 유지되는 일수가 지속되면 원기생성 및 능이 자실체의 생장에 많은 악영향을 미치는 것으로 판단된다. 6. 본 연구를 통하여 능이의 발생과 관련한 인자들 중에서 토양수분과 기온이 능이의 발생에 얼마나 많은 영향을 미치는지 확인할 수 있었다. 향후 능이와 관련한 다양한 기상인자들의 자료수집이 지속되어야 할 것이며, 현재까지의 연구결과를 바탕으로 하여 이런 인자들이 능이발생에 미치는 영향 또한 자세히 규명되어야 할 것이다. 이를 토대로 지속적인 능이의 발생과 증산을 위해서 고온장해를 피하기 위해서 지온의 유지와 토양수분의 유지를 위한 적절한 관수시점의 규명도 필 요할 것이다.