PURPOSES : This study was conducted to develop expressway safety treatments based on the analysis results of older driver behaviors through literature review, surveys, and driving simulator experiments. METHODS: In this study, three analyses were conducted: surveys of 700 older drivers to find the risk segments they recognized, driving simulator experiments with older and younger drivers to investigate driver behaviors, and expert surveys to find the priority of expressway safety treatments for older drivers. RESULTS : Through survey results it was found that merging areas and tunnels were identified as the most dangerous areas, and more dangerous older driver behaviors were observed on those expressway segments in the driving simulator experiments. In addition, the priorities of safety treatments for each segment of expressways were decided based on expert surveys. CONCLUSIONS: It was concluded that choice and concentration strategies of expressway safety treatments for older drivers should be applied as perceptions regarding dangerous spots and older driver behaviors, including geometric designs, safety facilities, regulation, and institutes to improve expressway safety.

PURPOSES : In this study, the effects of installation of diagonal crosswalks on traffic flow depending on the types of intersections are analyzed. METHODS : Scrambled crosswalks have advantages in the traffic safety. Therefore, a comparative analysis of the overall average delay before and after installation of the scrambled crosswalk was conducted using VISSIM. RESULTS: The overall average delay for the scrambled crosswalk decreased when the traffic volume ratio of the major to the minor street is 1: 6 in 2-by-1 and 3-by-1 types of intersections. The scrambled crosswalk improved efficiency of traffic operation in intersections: higher traffic volume for a major street, lower traffic volume for a minor street, and longer cross-distance for a major street. CONCLUSIONS: This study can be used to determine when a scrambled crosswalk should be installed to improve operational efficiency.

교차로 신호계획 수립은 여러 가지 중요한 요소를 포함하고 있다. 특히 부도로의 녹색시간은 주도로를 횡단하는 보행자의 녹색시간에 영향을 받는다. 주도로의 녹색시간 또한 부도로를 횡단하는 보행자의 녹색 시간에 영향을 받지만, 도로위계상 주도로는 부도로에 비해 교통량이 많고 부도로는 비교적 차로수가 적 기 때문에 부도로의 횡단시간에 영향을 크게 받지 않는다. 그러나 부도로의 좌회전 또는 직진 교통류의 녹색시간은 최소한 주도로를 횡단하는 보행녹색시간보다 커야 한다. 이로 인해 부도로에서 진출하는 교통 량이 많지 않더라도 일정시간 이상의 녹색시간을 부여하여야 하므로 신호계획에 있어서 불필요한 시간이 발생하게 된다. 따라서 주도로의 용량이 초과되어 전체 교차로 서비스수준(LOS)은 감소하게 된다. 일반적으로 대각선횡단보도는 전체 교차로의 지체를 발생시킨다. 그러나 대각선횡단보도를 설치하게 되면 보행전용현시에서 횡단보행자를 모두 소거시킬 수 있기 때문에 위와 같은 최소녹색시간의 제약을 받 지 않고 부도로의 실제 교통량에 따라 신호계획을 수립할 수 있는 장점이 있다. 따라서 본 연구에서는 VISSIM 프로그램 분석을 통해 대각선횡단보도 설치 전․후의 평균차량지체(sec/veh)를 비교분석하였다. 분석결과를 토대로 대각선횡단보도를 설치함으로써 교차로 서비스수준(LOS)을 향상시킬 수 있는 교차로 유형과 주도로 및 ․부도로 교통량 비율을 제시하는 것을 목적으로 한다. 분석결과, 편도 2*1 교차로와 편도 3*1 교차로에서 부도로와 주도로의 교통량비가 1:6 이상일 경우 대 각선횡단보도를 설치하여도 평균차량지체가 감소하게 되는 것으로 나타났다. 즉 부도로의 교통량이 많지 않고, 주도로의 교통량이 많고 부도로보다 차로폭이 클 경우 대각선횡단보도를 설치하면 차량소통측면에 서 효과를 볼 수 있다. 본 연구의 결과는 대각선 횡단보도를 설치 시 효율적인지를 결정할 수 있는 기초결 과로 제공될 것으로 기대된다.

교통사고 잦은 곳 개선사업은 2010년까지 사업대상지점만을 선정하여 개선사업을 진행하였지만, 2011 년부터 지점뿐만 아니라 구간을 선정하여 개선사업을 추진하고 있다. 그러나 현재까지 사업대상구간을 선 정하는 방법이 명확하지 않은 문제가 있어 사업대상구간 선정 시 혼란이 가중되고 있는 실정이다. 또한 지방부 도로와 같이 교차로가 많지 않은 구간의 사업대상구간 선정은 비교적 수월하지만, 도시부 도로의 교차로가 많은 구간에서는 정량적인 기준을 통해 어떤 구간을 어떻게 선정하여야 하는지 명확한 기준이 없다. 따라서 본 연구에서는 교차로가 많은 특성을 가지고 있는 도시부 도로에서의 사고 잦은 곳 사업대 상구간을 정량적으로 선정할 수 있도록 방법론을 개발하였다. 교통사고 DB는 도로교통공단 교통사고분석시스템(TAAS)을 통해 2012년 발생한 사고 DB를 수집하였 다. 대상구간은 서울시 동작구, 경기도 안양시, 전주시 완산구 13개 축을 선정하여 교통사고 건수 및 심각 도를 분석하였다. 이를 통해 교통사고 잦은 구간을 선정하는 2가지 대안을 제시하였고, 대표성, 구간 선 정 편리성, 범용성, 시스템 적용성 측면에서 대안별 장단점을 분석하여, 최적안을 도출하였다.

PURPOSES: This study dealt with traffic accidents occurring within roundabouts. The objective of this study was to analyze safety effect by introduction of roundabouts. METHODS: In pursuing the above, traffic accident data on roundabouts are collected and compared. For the analysis, collected data were separated as all intersection points, turning lane accident, approach lane accident by geometric design. RESULTS : Through the study results, it was found that the total accidents decreased by 55 accidents/2 year with safety effect of roundabouts. Also the result shows that accidents by point of two-lane roundabout at turning lane(0.26) and approach lane(0.27) is risky than total accidents by point(0.09). Moreover, accidents by point shows high value as diameter of a roundabout is bigger. CONCLUSIONS: When a roundabout is introduced at the intersections there are safety effects by reduction of traffic accidents.

소나무재선충병의 생물학적 방제인자를 탐색하기 위하여 소나무 고사목, 토양 등에서 선충 포획 능력이 있는 선충포식성 곰팡이를 소나무 고사목 및 토양 시료에 서 40균주를 선발하여 배양 특성 및 재선충병 감염목 내 재선충 밀도 저하 효과 등을 조사하였다. 소나무재선충은 1/6 nutrient agar에 소나무 고사목 및 토양 샘플을 치 상하고, 500마리의 소나무재선충을 접종한 후, 25℃ 항온기에서 배양하면서 1~2일 간격으로 선충 포획기관을 형성하는 곰팡이에 의해 치사된 균주가 형성하는 분생 포자를 순수 분리하여 PDA배지를 이용하여 계대배양을 실시하였다. 분리된 40균 주는 25~30℃ 온도 조건에서, pH 5~8의 범위에서 생육이 양호하였으며, 1/6 nutrient agar에서 분생포자를 유도하여 Ø 5㎜ 드릴로 천공한 후 배지와 함께 1g의 균주를 접종하여 60일 경과 후 최종 선충 밀도를 조사하였으며 4개 균주가 현저한 소나무재선충 억제효과를 보여 소나무재선충병 방제 이용 가능성을 시사하였다.

Cobots are industrial robots with greatly enhanced safety functions that enable them to work in the same space with workers without protector. Cobots are regulated by the Industrial Safety and Health Act and must be certified according to the manufacturing stage, installation stage and usage stage. The ISO 10218-2 standard applied in the installation phase is difficult to apply in the field. Therefore, it is necessary to develop a risk assessment method based on ISO 12100 standard. This paper proposes a new methodology that combines ‘JSA’ and ‘What-if’, which reflects the human error and the lack of known risk factors. Accordingly, a new risk assessment template was proposed and the effectiveness of the developed new template was examined. The current cobot safety regulations need to be unified with safety inspections scheme, and robot safety experts and infrastructures need to be expanded and Robot safety regulations should be unified to ‘Robot Act’. Based on this research, risk assessment methods suitable for the field need to be developed additionally, and robot safety regulation needs to be transformed to promote the industry.

The photocatalytic decomposition characteristics of toluene, acetone, and methyl mercaptan (MM) by UV reactor installed with TiO2-coated perforated plane were studied. The removal efficiency of single toluene, acetone, and MM vapor was increased with increasing oxygen concentration, but decreased with increasing inlet concentration. Elimination capacity of single toluene, acetone, and MM vapor was obtained to be 628 g/m3․day, 1,041 g/m3․day, and 2,158 g/m3․day, respectively. Also, the photocatalytic decomposition of binary vapor consisted of toluene and acetone, toluene and MM, acetone and MM were observed. Elimination capacity of toluene mixed with acetone, toluene mixed with MM, acetone mixed with toluene, acetone mixed with MM, MM mixed with toluene, and MM mixed with acetone was 327 g/m3․day, 512 g/m3․day, 128 g/m3․ day, 266 g/m3․day, 785 g/m3․day and 883 g/m3․day, respectively. The inhibitory effect of acetone was higher than MM in photocatalytic decomposition of toluene, the inhibitory effect of toluene was higher than MM photocatalytic decomposition of acetone, and the inhibitory effect of toluene was higher than acetone in photocatalytic decomposition of MM.

The feasibility of PS-D2EHPA/TBP beads prepared by immobilizing two extractants D2EHPA and TBP in polysulfone to remove Sr(II) from aqueous solution was investigated in batch system. Batch experiments were carried out to study equilibrium isotherms, kinetics, and thermodynamics. Equilibrium data were fitted using Langmuir, Freundlich, Redlich– Peterson, and Dubinin-Radushkevich equation models at temperatures of 298 K, 313 K, and 328 K. The removal capacity of Sr(II) by PS-D2EHPA/TBP beads obtained from Langmuir model was 2.41 mg/g at 298 K. The experimental data were well represented by pseudo-second-order model. The removal process of Sr(II) by PS-D2EHPA/TBP beads prepared in this study was found to be feasible, endothermic, and spontaneous.

The solid-phase extractant PS-D2EHPA/TBP was prepared by immobilizing two extractants D2EHPA and TBP in polysulfone (PS). The prepared PS-D2EHPA/TBP was characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The removal of Cu(II) from aqueous solution was investigated in batch system. The experiment data were obeyed the pseudo-second-order kinetic model. Equilibrium data were well fitted by Langmuir model and the removal capacity of Cu(II) by solid extractant PS-D2EHPA/TBP obtained from Langmuir model was 3.11 mg/g at 288 K. The removal capacity of Cu(II) was increased according to increasing pH from 2 to 6, but the removal capacity was decreased below pH 3 remarkably.

In this study, the photocatalytic decomposition characteristics of single toluene, toluene mixed with benzene, toluene mixed with acetone, and toluene mixed methyl mercaptan (MM) by UV reactor installed with TiO2-coated perforated plate were studied. The photocatalytic decomposition rate of single toluene, toluene mixed with benzene, toluene mixed with acetone, and toluene mixed with MM fitted well on Langmuir-Hinshelwood (L-H) kinetics equation. The maximum elimination capacity was obtained to be 628 g/m3·d for single toluene, 499 g/m3·d for toluene mixed with benzene, 318 g/m3·d for toluene mixed with acetone, and 513 g/m3·d for toluene mixed with MM, respectively. The negative effect in photocatalytic decomposition of toluene are found to be in the order of acetone>benzene>MM.

Abstract PS-D2EHPA beads were prepared by immobilizing di-2-ethylhexyl-phosphoric acid (D2EHPA) with polysulfone (PSf). The removal experiments of Cu(II) and Pb(II) by the prepared PS-D2EHPA beads were conducted batchwise. The removal efficiency of Cu(II) and Pb(II) by PS-D2EHPA beads was increased with increasing pH of solution. The removal rate of Cu(II) and Pb(II) was well described by the pseudo-second-order kinetic model. The maximum removal capacity of Cu(II) and Pb(II) obtained from Langmuir isotherm were 2.58 mg/g and 12.63 mg/g, respectively. External mass transfer coefficients for the removal of Cu(II) and Pb(II) by PS-D2EHPA beads were obtained 0.61×10-2∼ 5.87×10-2 /min and 1.55×10-2∼8.53×10-2 /min, respectively and diffusion coefficients were obtained 1.32×10-4∼ 3.98×10-4 cm2/min and 1.80×10-4∼2.28×10-4 cm2/min, respectively.

The photocatalytic decomposition characteristics of single n-pentane, n-pentane mixed with methyl ethyl ketone (MEK), and n-pentane mixed with ethyl acetate (EA) by cylindrical UV reactor installed with TiO2-coated perforated plane were studied. The effects of the residence time, the inlet gas concentration, and the oxygen concentration were investigated. The removal efficiency of n-pentane was increased with increasing the residence time and the oxygen concentration, but decreased with increasing the inlet concentration of n-pentane. The photocatalytic decomposition rates of single n-pentane, n-pentane mixed with MEK, and n-pentane mixed with EA fitted well on Langmuir-Hinshelwood kinetics equation. The maximum elimination capacities of single n-pentane, n-pentane mixed with MEK, and n-pentane mixed with EA were obtained to be 465 g/m3․day, 217 g/m3․day, and 320 g/m3․day, respectively. The presence of coexisting MEK and EA vapor had a negative effect on the photocatalytic decomposition of n-pentane and the negative effect of MEK was higher than that of EA.

The adsorption ability of wood-based activated carbon to adsorb methylene blue (MB) and crystal violet (CV) from aqueous solution has been investigated. Adsorption studies were carried out on the batch experiment at different initial MB and CV concentrations (MB=150 mg/L～400 mg/L, CV=50 mg/L～350 mg/L), contact time, and temperature. The results showed that the MB and CV adsorption process followed the pseudo-second-order kinetic and intraparticle diffusion was the rate-limiting step. Adsorption equilibrium data of the adsorption process fitted very well to both Langmuir and Freundlich model. The maximum adsorption capacity (qm) by Langmuir constant was 416.7 mg/g for MB and 462.4 mg/g for CV. The thermodynamic parameters such as ΔH°, ΔS° and ΔG° were evaluated. The MB and CV adsorption process was found to be endothermic for the two dyes.