This study aims to calculate the passenger car equivalent (PCE) of heavy vehicles on one-lane exit sections of underground roads. Traffic-flow simulations were performed using the VISSIM software program. The scenarios were designed under varying conditions, including design speeds of 40 and 50 km/h, slope gradients ranging from 3% to 9%, and heavy vehicle proportions between 5% and 40%. The mixed-traffic flow capacity was calculated for each scenario at the threshold levels, and the PCE was estimated based on the two capacity conditions. The results revealed that the PCE decreased at lower design speeds. For slopes less than 6% at a design speed of 40 km/h, and for slopes less than 4% at 50 km/h, the PCE remained consistent across all conditions. Single-lane exit sections are often employed on underground roads because of congestion and structural constraints. However, when heavy vehicles are present in these sections, the overall traffic flow is dictated by the speeds of the heavy vehicles. To address this issue, the implementation of variable or temporary two-lane exit sections has been proposed to enhance traffic flow and capacity.

In this study, various pre-treatment methods were evaluated for microalgae separation. These methods aimed to facilitate safe, rapid, and cost-effective online imaging for real-time observation and cell counting. As pre-treatment techniques, heating, chemical hydrolysis, heating combined with chemical hydrolysis, and sonication were employed. The effectiveness of these methods was evaluated in the context of online imaging quality through experimentation on cultivated microalgae (Chlorella vulgaris and Scenedesmus quadricauda). The chemical treatment method was found to be inappropriate for improving image acquisition. The heating pre-treatment method exhibited a drawback of prolonged cell dispersion time. Additionally, the heating combined with chemical hydrolysis method was confirmed to have the lowest dispersion effect for Chlorella vulgaris. Conversely, ultrasonication emerged as a promising technique for microalgae separation in terms of repeatability and reproducibility. This study suggests the potential for selecting optimal pre-treatment methods to effectively operate real-time online monitoring devices, paving the way for future research and applications in microalgae cultivation and imaging.

PURPOSES : The purposes of this study are to identify appropriate numbers of drivers for different time periods by analyzing the service times of the Special Transportation System and to shorten the waiting time to within 15 minutes. METHODS : In this study, the service time is divided into the call connection time (At), dispatch time after reception (Bt), vehicle arrival time after dispatch (Ct), and vehicle boarding time (Dt), and the annual average value for each time zone is calculated by analyzing the dispatch system database. Furthermore, the number of drivers working in each time period is extracted and the appropriate number of drivers for ensuring the dispatch waiting time remains within 15 minutes is determined. RESULTS : It is more accurate to interpret the decrease in dispatches during lunchtime as a decrease in the number of operational vehicles owing to the drivers' lunchtimes rather than a decrease in demand. During lunchtime (as in previous studies) the number of operations decreases, but the average dispatch time (Bt) greatly increases to 22:42; thus, it cannot be seen as a decrease in dispatch demand. The number of operations during lunchtime is proportional to the number of drivers on duty. The number of drivers on duty is inversely proportional to the average dispatch time. If the number of drivers is increased by 11.6%, the average waiting time can be reduced to within 15 minutes. CONCLUSIONS : To resolve delayed call connection issues, we will introduce an artificial intelligence (AI) call center. During the hours of 7 PM to 6 AM, calls will mainly be handled by AI and the counseling personnel will switch to daytime work. We will also increase the number of drivers by 11.6% to ensure that the dispatch time does not exceed an average of 15 minutes after receiving a call. In particular, we will generate the work schedule such that more than 131 drivers work in the 12:00 to 13:00 hours during lunch time to improve the situation where users have to wait for a long time. To do this, we will overlap the work hours for 2 hours in Jeonju and 1 hour in other cities and counties. We have to increase the number of night shift workers from seven to 15 so that all cities and counties can operate vehicles 24 hours a day, 365 days a year.

본 연구의 목적은 노화에 따라 나타나는 시공간 주의배분능력과 정서지각 편향성의 변화에 대해 탐구하는 것이다. 본 연구에서는 시공간 주의배분능력을 측정하기 위해 useful field of view (UFOV) 과제와 정서지각 편향성을 측정하 기 위해 정서지각과제(emotional perception task)를 사용하였다. 본 연구에는 노인 집단의 23명과 청년 집단의 25명의 총 48명의 실험참가자가 참여하였다. 실험 결과, UFOV 과제에서는 노인 집단이 청년 집단에 비해 느린 반응속도와 낮은 정답률을 보여 노인 집단이 청년 집단보다 저하된 시공간 주의배분능력을 가지고 있다는 것을 나타냈다. 또한, 정서지각과제에서는 노인 집단이 청년 집단에 비해 긍정적 정서지각 편향성과 부정적 정서지각 편향성 모두 크게 나타났다. 상관분석 결과에서는 정서지각과제의 정답률에 대한 부정적 정서지각 편향성이 UFOV 과제의 시야각 30° 조건의 반응속도와 유의미한 정적 상관관계가 나타났다(r=.289). 또한, 정서지각과제의 정답률에 대한 긍정적 정서지각 편향성은 UFOV 과제의 모든 시야각 조건들의 정답률과 유의미한 정적 상관관계가 나타났으며(r=.305, r=.322, r=.299), 반응속도와 유의미한 부적 상관관계가 나타났다(r=-.345, r=-.295, r=-.308). 이러한 결과는 노화가 저하된 시공간 주의배분능력 그리고 긍정적 정서지각 편향성과 부정적 정서지각 편향성의 증가와 관련있다는 것을 의미하고, 노화에 따라 나타나는 긍정적 및 부정적 정서지각 편향성은 저하된 시공간 주의배분능력과 관련성이 있는 것으로 여겨진다.

본 연구의 목적은 사회공포증 수준에 따른 정서지각 편향성의 변화와 이 변화에 기여하는 시공간 주의배분능력에 대해 탐구하는 것이다. 이를 위해, 본 연구에서는 사회공포증 수준을 측정하기 위해 한국형 자기보고식 설문 검사인 사회공포증 검사(Korean version of social avoidance and distress, K-SAD)를 사용하였으며, 정서지각 편향성과 시공간 주의배분능력을 측정하기 위해 정서지각 과제(emotional perception task)와 UFOV 과제(useful field of view task)를 사용하였다. 본 연구에는 118명의 연구참가자가 참여하였고 응답을 성실하게 하지 않은 연구참가자들을 제외하여 107명(남: 94명, 여: 13명)의 자료가 분석되었다. 연구참가자들은 K-SAD 점수에 따라 세 집단으로 나뉘어졌다. 연구 결과, 정서지각과제에서 긍정적 정서지각 편향성은 사회공포증 수준이 높을수록 더 크게 나타났으며 UFOV 과제에서는 사회 공포증 수준이 높을수록 저하된 시공간 주의배분능력이 나타났다. 이러한 결과는 사회공포증 수준의 증가에 따라 나타나는 저하된 시공간 주의배분능력이 긍정적 정서지각 편향성에 부분적으로 기여할 가능성이 있다는 것을 시사한다.

PURPOSES : This study was purposed to investigate whether the current passing sight distance standard is appropriate. Therefore, to determine a safe passing sight distance, data collected from the observations of a two-lane road were implemented in reliability analysis to develop a realistic passing sight distance model. METHODS : First, passing sight distance data were collected for analysis from two-lane roads in Jeollabuk-do. Next, the speed profile was generated based on the collected data in order to analyze driver behavior. Finally, a model reflective of the driving behavior of motorists was developed and compared to the existing passing sight distance standard using reliability analysis. RESULTS : As compared to the existing model for safe passing sight distance, the actual speed of the overtaking vehicle indicated higher acceleration and a longer acceleration duration. The entire model, with exception of the d1 section, was modified to reflect the overtaking behavior of motorists d1. d2 was set to correspond to the time until the vehicles run side by side (t21); Time t22 was set to correspond to the time until subsequent recovery to the main lane, and d3 was set to range between 19 and 47 m following review of the actual passing sight distance data. In addition, d4 was computed to be two-thirds of the distance d2, and the oncoming car was found to drive at a constant speed that was similar to the speed associated with d2 . Analysis of the reliability of the existing Korean passing sight distance standard revealed that the current standard does not recommend a safe passing sight distance for drivers. CONCLUSIONS : As compared to the existing passing sight distance criterion, the actual speed and acceleration that driver apply to overtake a vehicle are higher, and the existing passing sight distance criterion is shorter than the actual passing sight distance. Additionally, the results of reliability analysis revealed that the proposed model developed to reflect driver overtaking behavior has more explanatory power than the existing one. Therefore, it is necessary to introduce new design standards that implement passing sight distance variables that are relevant to local drivers.

본 연구의 목적은 노화에 따른 작업기억능력의 저하에 영향을 받는 자막인식위치에 대해 탐구하는 것이다. 이를 위해, 본 연구에는 주니어 집단(평균 나이: 26세, 표준편차: 3.06, N=27)과 시니어 집단(평균 나이: 61.69세, 표준편 차: 4.18, N=26)이 참여했으며, 실험 과제로는 실험 참가자들의 작업기억능력을 측정하기 위한 N-back 과제와 자막 인식위치를 측정하기 위한 동영상자막확인 과제가 사용되었다. N-back 과제 수행 결과, 시니어 집단이 주니어 집단 보다 과제에 대한 반응속도가 느리고 정답률이 낮게 나타나, 시니어 집단은 주니어 집단에 비해 작업기억능력의 저하가 나타났다는 것을 의미했다. 또한, 동영상자막확인 과제 수행 결과, 노화에 따른 작업기억능력의 저하에 부정적인 영향을 받는 자막위치는 화면의 ‘좌측-아래’이고 긍정적인 영향을 받는 자막위치는 화면의 ‘좌측-가운데’으로 나타났다. 나머지 화면 위치에서는 노화에 따른 작업기억능력의 저하에 영향을 받지 않았다. 결과적으로 본 연구 결과를 통해서 연령의 증가에 따른 작업기억능력의 저하에 부정적 혹은 긍정적 영향을 받는 영상 속 자막인식위치에 대해서 살펴볼 수 있었으며, 이는 영상에 자막을 제시해야할 경우 시청자의 연령을 고려하여 자막위치를 선정하면 효율적으로 시청자에게 정보를 제공할 수 있다는 것을 의미했다.