Black carbon (BC), which is mainly contained in fine particulate matters, is one of the typical anthropogenic air pollutants that are generated from the incomplete combustion process and discharged into the atmosphere, and its various health effects particularly on children have been a growing concern. In this study, BC and particulate matters were closely analyzed in an elementary school adjacent to a high- traffic road in a large metropolitan city. The investigation showed that black carbon behaved similarly to ultrafine dust of 0.3 μm or less in the air, accounting for 20%-40% of it. The occurrence of high concentration outdoor pollution influences the BC content in indoor particulate matters. The average I/O value was 0.7 during the class-hours, and 0.8 without students. However, when students played in the classroom, the range of BC concentrations varied from 0.25 to 1.15, wider than 0.41-1.13 without students. Although this study was conducted with regard to just one elementary school, it can be considered to represent the typical air quality status of domestic schools, and it is believed to present valuable data which can be utilized to assist with preparing measures to enhance the air quality management of schools.

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 : In this study, model-agnostic methods are applied for interpreting machine learning models, such as the feature global effect, the importance of a feature, the joint effects of features, and explaining individual predictions. METHODS : Model-agnostic global interpretation techniques, such as partial dependence plot (PDP), accumulated local effect (ALE), feature interaction (H-statistics), and permutation feature importance, were applied to describe the average behavior of a machine learning model. Moreover, local model-agnostic interpretation methods, individual conditional expectation curves (ICE), local surrogate models (LIME), and Shapley values were used to explain individual predictions. RESULTS : As global interpretations, PDP and ALE-Plot demonstrated the relationship between a feature and the prediction of a machine learning model, where the feature interaction estimated whether one feature depended on the other feature, and the permutation feature importance measured the importance of a feature. For local interpretations, ICE exhibited how changing a feature changes the interested instance’s prediction, LIME explained the relationship between a feature and the instance’s prediction by replacing the machine model with a locally interpretable model, and Shapley values presented how to fairly contribute to the instance’s prediction among the features. CONCLUSIONS : Model-agnostic methods contribute to understanding the general relationship between features and a prediction or debut a model from the global and/or local perspective, securing the reliability of the learning model.

PURPOSES : The objective of this study is to develop regression models for surface distress (SD), rut depth (RD), and international roughness index (IRI) of Jeju Island local road by analyzing the correlations between the pavement performance and its influencing factors. METHODS : First, the differences between pavements in inland Korea and Jeju Island in terms of performance and influencing factors were investigated. Influencing factors were assigned to pavement sections on Jeju Island using the inverse distance weighting method, and the correlations between the pavement performance and influencing factors were analyzed. As a result, maximum temperature, heat wave days, annual temperature range, precipitation days, precipitation intensity, ESAL, etc. were determined as independent variables for the pavement performance prediction models. Multiple regression analysis was performed to develop the pavement performance models using the selected independent variables. RESULTS : The RD, maximum temperature, and precipitation days were determined to be the independent variables for the SD predictive model. The SD, maximum temperature, annual temperature range, heat wave days, and precipitation days were selected as independent variables of the RD prediction model. In addition, the RD, annual temperature range, heat wave days, precipitation days, and ESAL were selected as independent variables for the IRI prediction model. CONCLUSIONS : As a result of the study, an actual forecast model for SD, RD, and IRI was developed. Based on this model, it is possible to estimate the predictive value of the missing performance data in the studied interval. If the factors affecting performance are managed in terms of maintenance beyond a certain level, it can help those responsible for road maintenance to rationally select the maintenance method and timing.

PURPOSES : The objective of this study is to evaluate the effectiveness of spraying dust suppressants in relation to the condition of road pavement in South Korea and to develop an optimal management method by continuously measuring re-suspended dust concentrations using a vehicle-based measurement. METHODS : Indoor experiments were conducted to select suppressants suitable for local conditions to reduce reducing road dust, which were identified through literature review. Data collection followed the evaluation method by selecting a section sprayed with dust suppressants and a non-sprayed section within the service road. RESULTS : The BPT experiment is designed to ensure the skid resistance of the road when dust suppressants are sprayed on the road. The Environmental toxic tests for PM10, HCHO, and TVOC all met the daily indoor air quality standards recommended in Korea for determining stability. Comparison of PM10 contents before and after spraying of the test road with dust suppressants and the non-sprayed section, it was confirmed that the dust suspended by the external environment may be reduced, but the amount of dust remaining on the road may increase. After 4 hours, when the water had evaporated, the dust suppressants remained effective and lasted for two-days. CONCLUSIONS : The concentration of fine dust in South Korea varies with the average duration of highly concentrated fine dust being 26.5 h nationwide, 20.5 h in the Seoul metropolitan area, and 25.1 h in Gyeonggi-province, suggesting a duration of one to two days. Thus, the fine dust problem can be solved by using dust suppressants.

Tin slag is a byproduct obtained from the tin smelting industry and contained naturally occurring radioactive material (NORM); therefore, it has to be managed accordingly. This study focuses on recycling the waste in exchange for natural aggregates for road pavement due to the potential features as construction materials. The main objective of this study is to analyze the use of tin slag by diluting its radioactivity level and as the replacement of natural aggregates while focusing on identifying the mechanical properties of the mixture. Tin slag was used as coarse aggregate in the range of 0–85% while the percentage of recycle glass was maintained at 15% and granite rocks in range of 0–100%. In this research, the concentration activity of NORM in tin slag have been measured using a gamma ray spectrometer. Few laboratory tests for the final product are carried out such as Los Angeles abrasion value (LAAV), aggregate crushing value (ACV), and aggregate impact value (AIV). This study was also conducted to analyze the leachability of As, Cd, Ba, Cr, Pb, Se and Ag from the different composition. From the measurement result, the average concentration of 226Ra, 232Th and 40K are 318.21 Bq·kg−1, 602.07 Bq·kg−1 and 89.84 Bq·kg−1, respectively. The outdoor dose rates were found to be lower than 1.5 mSv·yr−1 in sample A1, A2 and A3 which is the recommended limit for construction materials. The sample toxicity was assessed using the toxicity characteristic leaching procedure (TCLP) and the concentration of the elements studied was analysed using ICP-MS. The result from the analysis indicated that the concentrations of the heavy metal elements were between 0.001–26.94 mg·kg−1, which is lower than the limit for each element. As a conclusion, addition of tin slag between 5 to 25% in exchange of granite rocks as road pavement have showed potential evidence in the test for construction material. Besides, it has low leachability to the environment while diluting the radioactivity level.

PURPOSES : This study aimed to develop data conversion of NGII HD maps to OpenDRIVE format for virtual road implementation for autonomous-driving verification. METHODS : A method of defining the reference line of OpenDRIVE on the centerline of an NGII HD map is proposed. According to the construction characteristics of the NGII HD map, the optimal conversion method through parametric cubic polynomials was used in the form of piecewise and clamped cubic polynomials. RESULTS : The study focused on curved roads that may cause problems when converting HD map data into OpenDRIVE formats. As a result of data conversion, a reference line was defined to precisely follow the alignment of NGII HD maps drawn based on MMS data, and a lively virtual road was reproduced through road lane width and lane expression. CONCLUSIONS : A virtual road in the same environment as a real road, which is one of the important factors in verifying autonomous driving technology through virtual driving simulation, was constructed. The piecewise-polynomial normal was 0.008 m on average, and as a result of calculating the distance between the endpoint coordinates of the road object and the endpoint coordinates of the converted road object on the NGII HD map, the difference between the two points was 0.163 m on average. The clamped cubic polynomials normal was observed to be an average of 0.170 m.

Bangladesh enjoys an advantageous geographical position. It has been a transit station for businessmen from South Asia, Southeast Asia, Central Asia and even Europe since ancient times. It is located at the intersection of China Economic Circle, South Asia Economic Circle and ASEAN Economic Circle, and is an important country along the belt and road initiative. The “Belt and Road” initiative was supported by Bangladeshi Prime Minister Sheikh Hasina. Since the “Belt and Road” initiative was put forward, China and Bangladesh have achieved remarkable results in policy communication, facility connectivity, smooth trade, capital financing and people-to-people communication. However, China and Bangladesh still face challenges in the political, security, economic and social fields to jointly build the “Belt and Road” initiative. In the new period, China and Bangladesh should strengthen political communication, promote the docking of China-Bangladesh development strategies, strengthen facility connectivity and industrial cooperation, promote cultural exchanges, promote the upgrading of cooperation between the two countries, and jointly build a high-quality “Belt and Road” initiative.

The global economy has been hit hard by the COVID-19 pandemic, and countries around the world urgently need to restore economic growth. As countries in Eurasia become more and more closely connected, it is inevitable for China's Belt and Road Initiative and South Korea's new Northern policy to connect. In this context, what matters is the connection of the railway network. The purpose of this study is to analyze the impact of the integration of the Korean Terminal Railway (TKR) into the Eurasian railway network by connecting the Korean Terminal Railway (TKR) with China's China-Europe freight trains. The results show that there is an interactive positive correlation between railway freight volume and GDP, and South Korea is expected to become the logistics center of East Asia and improve its status and influence in the world center. Within the Korean peninsula, the railway connection can draw North Korea into a larger multilateral agreement system, and South Korea can use external forces within the system to push North Korea to seek more economic cooperation and actively promote the reunification process. The economic development of Northeast Asia also plays a positive role in the economic recovery of the three provinces in northeast China.

2018년 음주운전차량에 윤창호 군이 사망하는 사고가 발생하고, 상습 음주운전에 대한 처벌을 강화하자는 국민들의 의견을 반영하여 도로교통 법 제148조의2 제1항이“제44조제1항 또는 제2항을 2회 이상 위반한 사람(자동차등 또는 노면전차를 운전한 사람으로 한정한다)은 2년 이상 5년 이하의 징역이나 1천만 원 이상 2천만 원 이하의 벌금에 처한다.”는 내용으로 일부개정이 있었다. 그런데 얼마 지나지 않아 2021. 11. 25. 헌법재판소에서 위 일부 개정된 도로교통법 중 제148조의2 제1항 중 “제44조 제1항을 2회 이상 위반한 사람”에 관한 부분이 헌법에 위반된 다는 위헌결정을 하였다. 헌법재판소는“제44조 제1항을 2회 이상 위 반”한 경우로 정하여 가중요건이 되는 과거 음주운전 금지규정 위반행위 와 처벌대상이 되는 재범 음주운전 금지규정 위반행위 사이에 아무런 시 간적 제한을 두지 않고, 죄질이 비교적 가벼운 유형의 재범 음주운전 행 위에 대해서까지 일률적으로 가중 처벌하도록 함으로써 형벌 본래의 기 능에 필요한 정도를 일탈하는 과도한 법정형을 규정한 것으로 책임과 형 벌 간의 비례원칙에 위반된다고 하였다. 그러나 음주운전의 행위태양 및 죄질의 경중에 차이가 있더라도 모두 반복된 음주운전 금지규정의 위반이라는 중요한 행위 반가치 지표적 측 면에서 다른 범죄들과 합리적으로 구별되는 동질의 범죄행위라고 볼 수 있으므로 개별적인 행위 태양을 고려하여 처벌규정을 더 세분화하지 않 았더라도 헌법이 요구하는 형벌체계에 어긋난다고 단정할 수 없다. 또한 비난가능성이 크지 않은 유형의 재범 음주운전의 경우를 위험한 반복적 음주운전행위와 동일하게 취급할 수 있다 하더라도 징역형 이외에 벌금 형이 있으므로 법관이 사실관계를 판단하여 양형을 통해 충분히 해결할 수 있는 부분이므로 이 사건 심판대상 조항의 가중처벌기준이 입법재량 을 현저히 일탈했다고 볼 수도 없다. 따라서 헌법재판소의 이 사건 위헌결정이 적절한지는 의문이다. 특히 상습 음주운전자에 대한 처벌조항이 강화되었음에도 여전히 도로교통법 (음주운전) 위반 발생건수가 감소되지 않고 있고, 국민들 사이에서 여전 히 음주운전 처벌강화에 대한 필요성이 언급되고 있으므로 이 사건 심판 대상조항을 위헌이라고 단정할 만한 국민들 사이의 법 감정에 변화도 존 재하다고 볼 수 없다. 이런 측면에서 헌법재판소가 이 사건 결정과 같은 위헌결정을 하고자 하였다면, 단순위헌결정이 아닌 법적 공백상태 및 형 벌규정의 위헌결정에 따른 소급적용으로 발생하는 재심 등의 여러 문제 를 고려하여 입법형성권을 존중하고 법적 안정성을 보장하기 위한 방편 으로서 헌법불합치 결정하는 것이 권력분립원칙에 더 부합한다고 할 것 이다.

Asphalt concrete(Ascon) is used to repair potholes and cracks. Special truck-mounted cargo boxes transport 200℃ asphalt concrete to repair potholes and cracks. However, long working and transportation hours to repair wide roads decrease the temperature of the asphalt concrete inside the cargo boxes. If the asphalt concrete temperature drops below 170℃, the adhesion with roads that need repair decreases. Therefore, the temperature of the asphalt concrete needs to be maintained for a long time. Conventional asphalt concrete cargo boxes are mostly burner-type models using hot air to prevent the temperature of the asphalt concrete from dropping. However, there are significant temperature differences between the asphalt concrete near and far away from the hot air, so the temperature decreases over time and leads to the disposal of large amounts of asphalt concrete. This causes waste of resources and environmental pollution. Therefore, this study proposed a heat dissipation cut-off type cargo box model to solve this problem and demonstrated its performance over conventional burner-type models through tests and analysis.

PURPOSES : This aim of this study is to develop a model for predicting road surface temperature using an LSTM network to predict road surface temperature associated with road icing. METHODS : A long short-term memory (LSTM) neural network suitable for time-series data with time correlation is used in the analysis. Moreover, an optimal neural network architecture is designed via hyperparameter search and verification using learning and validation data. Finally, the generalization performance is evaluated based on the RMSE using unseen data as test data. RESULTS : The results show that the predicted data are similar to the actual road surface temperature patterns , and that the network appears to be generalized. CONCLUSIONS : The LSTM model improves the accuracy and generalization of road surface temperature prediction, as compared with other machine learning models.

of actual and suspicious black-ice cases that occurred during the last 10 years in the Republic of Korea. METHODS : Based on literature review, meteorological observation data associated with black-ice formation are selected: wind speed, air temperature (T), dew point temperature (Td), and relative humidity, to set minimum or maximum threshold values based on the normal distribution of each variable. In addition, weights are assigned based on the relationship among the variables to calculate the probability of occurrence. RESULTS : The threshold values are calculated using the average and standard deviation, resulting in 7.65 °C, 56.63%, 2.99 ms-1 for T-Td, relative humidity, and wind speed, respectively. Whereas the threshold value of T-Td and wind speed is set to the maximum threshold, that of the relative humidity is set to the minimum threshold value. These threshold values are applied to the diagnosis algorithm of black-ice formation, including a 1-h accumulated precipitation. CONCLUSIONS : The algorithm is expected to be utilized as a research methodology for diagnosing suspected cases of black ice.

PURPOSES : The purpose of this study is to establish a scientific and rational structure pavement maintenance technique and management standard through field investigation and analysis method development for measuring damage to structure pavement such that fundamental quality improvement can be promoted and the life of pavement prolonged. METHODS : In this study, the crack, plastic deformation, IRI, and SPI values measured using the existing RoadScanner of a corresponding section, as well as the relative dielectric constant values of a lower deck measured using a ground penetrating radar are reduced. The results of a small impact load test are verified by comparing the modulus of elasticity measured. RESULTS : In the Hongjecheon Overpass, when comparing the suspicion points of deterioration between the center of the lane and the 25 measurement data points of the wheel pass section based on the elastic modulus of the light falling weight deflectometer (LFWD), it is discovered that the lane comprises four centers (16%) and 18 wheelpaths (72%). The percentage of suspected deterioration points in the center is higher than that in the wheelpath. In addition, in the case of the Seoho Bridge, by comparing the suspicious points of deterioration for 11 measurement data points in the middle of the lane and the wheelpath section based on the elastic modulus of the LFWD, it is discovered that five points (45%) in both the middle of the lane and the wheel pass are similar. CONCLUSIONS : In this study, a comparative analysis of the LFWD elastic modulus and SPI factors (crack rate, plastic deformation, and IRI) of the Hongjecheon Overpass and Seoho Bridge is conducted to confirm the factors of pavement breakage. Among them, it is confirmed that it affects the pavement condition the most; however, to consider the LFWD elastic modulus as an evaluation criterion for future structure pavement, the data points must be verified via additional experiments to ensure high reliability.

본 연구는 도로 노면결빙 판정 알고리즘에 대해 알고리즘을 개선하고 실제 현장 측정 자료와 알고리즘 예측값을 비교하였을 때 알고리즘에 대한 적중률을 분석하였다. 분석을 위하여 포천시 신북면 금 동리의 도로 및 기상을 측정하였다. 알고리즘은 기존 도로 결빙 알고리즘을 선정하여 실제 결빙 조건 및 측정 수치에 맞춰 4차 알고리즘까지 개선하였다. 최종적으로 응결에 의한 결빙, 강수에 의한 결빙, 적설에 의한 결빙, 결빙상태의 지속, 풍속에 의한 결빙 5개의 알고리즘을 제작하였다. 포천 현장에서 알고리즘을 활용하여 예측할 경우 경우 결빙 적중률이 93.22%까지 개선되었다. 결빙 알고리즘에 대한 조합 비율에 대 해 도출하였을 때 응결에 의한 결빙과 결빙상태의 지속에 대한 알고리즘이 96%를 차지하였다.