This study aimed to assess the current global efforts to reduce greenhouse gas emissions and understand the domestic scenario, particularly focusing on pavement-marking works during road-construction projects. Using internationally commercialized programs, this study aimed to calculate carbon emissions from these projects, identify areas that require further action or improvement, and propose strategies to address them. This study assessed the current global efforts to reduce greenhouse gas emissions and understand the domestic scenario, particularly focusing on pavement-marking works during road-construction projects. Using internationally commercialized programs, this study aimed to calculate carbon emissions from these projects, identify areas that require further action or improvement, and propose strategies to address them. Carbon dioxide emissions from pavement-marking projects were estimated. For a 5,746 m2 construction project, a total of 96.637 was emitted; for a 5,032 m2 project with four types of markings, 89.840 was emitted. A project involving five types of markings, traffic controls, and safety measures resulted in 6.662 emissions. On average, 16.8 was emitted per 1 m2, with 17.8 for the four types and 9.3 for the five types of markings. This study is significant because it calculated the carbon dioxide emissions from domestic pavement-marking works. The use of unit price data is convenient, and for more accurate calculations, expanding environmental product declaration (EPD) certified items and accelerating the establishment of a domestic life-cycle inventory (LCI) are recommended.

Solar energy has been recognized as an alternative energy source that can help address fuel depletion and climate change issues. As a renewable energy alternative to fossil fuels, it is an eco-friendly and unlimited energy source. Among solar cells, thin film Cu2ZnSn(S,Se)4 (CZTSSe) is currently being actively studied as an alternative to heavily commercialized Cu (In,Ga)Se2 (CIGS) thin film solar cells, which rely upon costly and scarce indium and gallium. Currently, the highest efficiency achieved by CZTSSe cells is 14.9 %, lower than the CIGS record of 23.35 %. When applied to devices, CZTSSe thin films perform poorly compared to other materials due to problems including lattice defects, conduction band offset, secondary phase information, and narrow stable phase regions, so improving their performance is essential. Research into ways of improving performance by doping with Germanium and Cadmium is underway. Specifically, Ge can be doped into CZTSSe, replacing Sn to reduce pinholes and bulk recombination. Additionally, partially replacing Zn with Cd can facilitate grain growth and suppress secondary phase formation. In this study, we analyzed the device’s performance after doping Ge into CZTSSe thin film using evaporation, and doping Cd using chemical bath deposition. The Ge doped thin film showed a larger bandgap than the undoped reference thin film, achieving the highest Voc of 494 mV in the device. The Cd doped thin film showed a smaller bandgap than the undoped reference thin film, with the highest Jsc of 36.9 mA/cm2. As a result, the thin film solar cells achieved a power conversion efficiency of 10.84 %, representing a 20 % improvement in power conversion efficiency compared to the undoped reference device.

PURPOSES : The purpose of this study was to investigate directions for future smart city transportation policies and service development by evaluating road service satisfaction levels and predicting future service demand. METHODS : A nationwide survey was conducted in Korea to develop a transportation service evaluation system based on the functions and objects of transportation. The satisfaction level of road service was evaluated using an analytic hierarchy process (AHP), promising service sectors were identified using the revised importance-performance analysis (IPA) technique, and detailed service demands by sector were suggested. RESULTS : The most valuable service value felt by the people was "safety" (weight 0.4), and the overall satisfaction level was 68.9 points, slightly exceeding "normal." As a result of analyzing the promising service sectors by dividing them into urban and rural areas, "handicapped, elderly, and pedestrians" were important in both areas, and "road facility maintenance" was classified as an additional promising sector for rural areas. CONCLUSIONS : People demand that future smart city transportation policies and services should be "people" and "safety" centered. In addition, it is necessary to pay attention not only to the development of new services but also to the improvement of problems with existing services and policies.

PURPOSES : The purpose of this study is to propose a method of quantitative bus deceleration and acceleration time based on automatic vehicle location data generated by a bus operating system. METHODS : The digital tachometer graph (DTG) data of commercial vehicles and the bus departure and arrival time data collected through the Korean bus information system (BIS) were matched and utilized to accurately reflect the deceleration and acceleration position of the bus. It was determined whether the bus arrived (or departed) at bus stations based on the BIS data, and the acceleration and deceleration times were calculated by classifying the bus status section (deceleration-stop-acceleration-driving) based on the DTG speed data. RESULTS : The deceleration and acceleration times calculated using the proposed method were analyzed using the z-test for the bus type and peak and non-peak times. Notably, there was a difference in the acceleration time for each vehicle type. The results were compared with the reference values of TCQSM and the calculated values, and the results were similar. CONCLUSIONS : This study is meaningful in that it conducted basic research on calculating the acceleration and deceleration times by fusing currently available data. In addition, new types of buses that have not been presented in the existing reference values have the advantage of being able to be calculated without a separate investigation if only data are produced according to the current bus management system.

PURPOSES : The purpose of this study is to review a method to estimate the average travel speed of the Bus Rapid Transit(BRT) section using the bus departure and arrival time data collected using the Korean bus information system (BIS). METHODS : To determine an average travel speed estimation model suitable for the BRT system in Korea, the speed estimated using the speed estimation model of TCQSM, which is used in the U.S., and that using the proposed speed estimation model that used the bus departure and arrival time data were compared with the actual travel speed using a t-test. RESULTS : The average travel speed estimated using the proposed method was more suitable for the actual average travel speed than that estimated using the TCQSM model. CONCLUSIONS : As a result of estimating the average travel speed, if the length of the link is 900 m, SBRT can be constructed on the existing road, but at least 1,200 m must be ensured to build SBRT in the new city. The proposed bus average travel speed estimation model can be used to review the BRT operational efficiency considering the speed limit, traffic signal, and dwelling time at bus stops in the planning and operation stages of the BRT.

PURPOSES : The purpose of this study is to disseminate the process of deriving the truck performance curve of Korea’s representative trucks in detail such that the relevant experts can use it in the future when re-selecting the representative trucks and deriving the truck performance curve accordingly. METHODS : To collect relevant data required to derive the truck performance curve, this study used four trucks that implemented the weight/power of the nation’s representative trucks, and conducted a practical driving test on four different upgrade sections. RESULTS : The truck performance curve was derived for each driving position to represent the deceleration and acceleration capabilities of the truck through the actual driving test on the upgrade sections. CONCLUSIONS : The truck performance curve derived from this study indicated that the truck’s deceleration and acceleration capabilities increased as the total weight/power of Korea’s representative trucks improved, and the design of the climbing lane demonstrated that the design method used in this study saved approximately 60% of the construction cost compared to the existing method.

PURPOSES : The purpose of this study is to enhance the reliability of artificial intelligence for a noise-based pavement condition rating system (to a target performance of 95 %). METHODS : By comparing four types of pattern recognition artificial intelligence, this work acquires high-quality learning data and optimizes data learning through analysis of error characteristics. RESULTS : The system reliability improved up to 97 % (82 % in a prior study). In addition, 100 % was achieved for the E(F) condition grade, which has a direct impact on maintenance decision making. CONCLUSIONS : KNN-DTW (K-nearest neighbor dynamic time warping) is judged to be the most suitable type of artificial intelligence for a noise-based pavement condition rating system; a 4-grade system is the most suitable for classifying pavement condition.

There have been great efforts to develop a rapid and sensitive detection method to monitor the presence of pathogenic bacteria in food. While a number of methods have been reported for bacterial detection with a detection limit to a single digit, most of them are suitable only for the bacteria in pure culture or buffered solution. On the other hand, foods are composed of highly complicated matrices containing carbohydrate, fat, protein, fibers, and many other components whose composition varies from one food to the other. Furthermore, many components in food interfere with the downstream detection process, which significantly affect the sensitivity and selectivity of the detection. Therefore, isolating and concentrating the target pathogenic bacteria from food matrices are of importance to enhance the detection power of the system. The present review provides an introduction to the representative sample preparation strategies to isolate target pathogenic bacteria from food sample. We further describe the nucleic acidbased detection methods, such as PCR, real-time PCR, NASBA, RCA, LCR, and LAMP. Nucleic acid-based methods are by far the most sensitive and effective for the detection of a low number of target pathogens whose performance is greatly improved by combining with the sample preparation methods.

PURPOSES : This study tries to develop the accident models of 4-legged signalized intersections in Busan Metropolitan city with random parameter in count model to understanding the factors mainly influencing on accident frequencies. METHODS: To develop the traffic accidents modeling, this study uses RP(random parameter) negative binomial model which enables to take account of heterogeneity in data. By using RP model, each intersection’s specific geometry characteristics were considered. RESULTS : By comparing the both FP(fixed parameter) and RP modeling, it was confirmed the RP model has a little higher explanation power than the FP model. Out of 17 statistically significant variables, 4 variables including traffic volumes on minor roads, pedestrian crossing on major roads, and distance of pedestrian crossing on major/minor roads are derived as having random parameters. In addition, the marginal effect and elasticity of variables are analyzed to understand the variables’impact on the likelihood of accident occurrences. CONCLUSIONS :This study shows that the uses of RP is better fitted to the accident data since each observations’specific characteristics could be considered. Thus, the methods which could consider the heterogeneity of data is recommended to analyze the relationship between accidents and affecting factors(for example, traffic safety facilities or geometrics in signalized 4-legged intersections).

도로의 악영향 및 악천후로 인해 교통사고 유발, 도로변 민원 등이 다수 발생하고 있다. 악영향 및 악 천후 요인별로 보면 기상상태 악화(폭우, 폭설, 안개 등)로 인한 교통사고는 1.4% 증가하였고, 치사율도 약 3배 높은 것으로 분석되었다. 도로교통소음으로 인한 사회적 비용은 연간 34조원(2012년)으로 2005년 대비 44% 증가하였고, 민원 발생 42,000건(2009년 기준)으로 인한 사회적 손실도 증가되고 있는 실정이 나, 실질적인 소음저감 혹은 소음 측정을 위한 정량적 실험시설은 부족한 현실이다. 야간 교통량이 전체 교통량 중 차지하는 비율은 약 30% 정도임에도 불구하고 야간 사고 발생건수의 48.5%, 사망자수의 53.5%를 차지하고 있어('11년 기준), 야간 교통량 비중 감안 시 주간대비 위험도 3배에 달하나 실규모 실 증실험은 거의 전무하다. 이와 같이 도로의 악영향 및 악천후에 의한 피해는 심각한 사고 또는 피해를 입히는 것으로 나타났으 며, 이를 예방하기 위한 관련된 연구 및 기술 개발이 진행되고는 있으나 산발적이며 실증실험 등이 없어 과학적인 효과 입증이 어려운 상황이다. 한국건설기술연구원에서는 이러한 사회적 문제로 대두되고 있는 교통사고 등을 근본적으로 해결하고, 국가 기준을 재검토하여 적정 기준을 정립하기 위하여, 기상환경 재현 도로 성능평가 실험시설을 유치하 여 국토교통부 국토교통기술촉진연구사업으로 경기도 연천에 구축중에 있다. 각 실험시설의 목표 사양은 표 1과 같다. 향후 실험시설 구축뿐만 아니라 실험시설 운영계획, 연구 활용계획 및 활성화방안을 수집하여 관련 연구, 성능평가 ․ 인증 사업에 활용할 경우 국내 도로 안전 및 시설 성능 수준이 한층 높아질 것으로 기대된다.

PURPOSES : The purpose of this study is to revise the weight to power ratio of the representative truck in S. Korea. So far, S. Korea has been using the unit lb/hp, and the construction machines were not considered in the evaluation of the performance of trucks. METHODS : This study was performed to recommend the use of ISO system of units, and to analyze the weight to power ratios of the representative trucks in S. Korea, including the dump trucks, concrete mixer trucks, and asphalt and concrete diffusers. RESULTS: From this study, the 85 percentile value of the weight to power ratio of the trucks in S. Korea’s was found to be 103.6 kg/kw. CONCLUSIONS : The performance standard for the representative truck has to be increased upward, considering the travel pattern of the dump trucks, concrete mixers, and asphalt and concrete diffuser trucks, travel distances, narrow area (work zone) of operation, and the saving in construction budget for climbing lane. Based on this study, the weight to power ratio of the representative truck in S. Korea could possibly be revised to 100~110 kg/kW.