PURPOSES : This study aimed to investigate the factors affecting the severity of traffic crashes caused by personal mobility (PM) devices compared with those involving victims. METHODS : Traffic crashes involving PM devices were used to build a non-parametric statistical model using a classification tree. Based on the results, the factors influencing both at-fault and victim-related crashes caused by PM devices were analyzed. The factors affecting accident severity were also compared. RESULTS : Common factors affecting the severity of traffic crashes involving both perpetrators and victims using PM devices include occurrences at intersections, crosswalks at intersections, single roads, and inside tunnels. Traffic law violations by PM device users (perpetrators) influence the severity of crashes. Meanwhile, factors such as the behavior of perpetrators using other modes of transportation, rear-end collisions, road geometry, and weather conditions affect the severity of crashes where PM device users are the victims. CONCLUSIONS : To reduce the severity of traffic crashes involving PM devices, it is essential to extend the length of physically separated shared paths for cyclists and pedestrians, actively enforce laws to prevent violations by PM device users, and provide systematic and regular educational programs to ensure safe driving practices among PM device users.

PURPOSES : The reliability of traffic volume estimates based on location intelligence data (LID) is evaluated using various statistical techniques. There are several methods for determining statistical significance or relationships between different database sets. We propose a method that best represents the statistical difference between actual LID-based traffic volume estimates and the VDS values (i.e., true values) for the same road segment. METHODS : A total of 2,496 datasets aggregated for 1-h LID and VDS data were subjected to various statistical analyses to evaluate the consistency of the two datasets. The VDS data were defined as the true values for comparison. Four different statistical techniques (procrutes, 2-sample t-test, paired-sample t-test, and model performance rating scale) were applied. RESULTS : In cases where there is a specific pattern (e.g., traffic volume distribution considering peak and off-peak times), distribution tests such as Procrustes or Kolmogorov-Smirnov are useful because not only the prediction accuracy but also the similarity of the data distribution shape is important. CONCLUSIONS : The findings of this study provide important insight into the reliability of LID-based traffic volume estimation. To evaluate the reliability between the two groups, a paired-sample t-test was considered more appropriate than the performance evaluation measure of the machine-learning model. However, it is important to set the acceptance criteria necessary to statistically determine whether the difference between the two groups in the paired-sample t-test varies according to the given problem.

Effective mixing of different-sized aggregates in mobile asphalt plant dryers is crucial for ensuring high-quality, consistent asphalt production. This study explores the application of spatial analysis techniques, particularly the Discrete Element Method (DEM), to understand and optimize the mixing process of aggregates in drum dryers. The research emphasizes the importance of proper mixing to achieve uniform moisture removal and heating across various aggregate sizes. Larger aggregates heat more slowly, while finer particles risk overheating or being carried away by air currents, necessitating careful management of the mixing process. Using LIGGGHTS, an open-source simulation framework, we conducted DEM simulations to analyze the spatial distribution and behavior of aggregates within a 3D model of a drum dryer. The study considered multiple factors affecting mixing efficiency, including drum inclination, rotational speed, and aggregate feeding frequency. Results indicate that the rotational speed of the drum dryer has the most significant impact on mixing effectiveness. The DEM simulations provided valuable insights into particle movement, heat transfer, and potential segregation issues within the dryer. Further investigations into additional factors that may influence aggregate mixing in drum dryers is recommended, paving the way for improved efficiency and quality in asphalt manufacturing.

본 연구의 목적은 공유형 개인이동장치 주차공간/면에 대한 이용자 중심의 선호도를 파악하는 것이다. 본 연구의 목적을 달성하기 위한 방법은 다음과 같다. 첫째, 문헌고찰을 통해 공유형 개인이동장치 주차공간/면에 대한 설계요소를 도출한다. 둘째, 주차공간/면 설 계요소 조합을 통해 공유형 개인이동장치 주차공간/면에 대한 설계대안을 도출한다. 셋째, 설문조사를 통해 공유형 개인이동장치 이용 자를 대상으로 주차공간/면 설계대안에 대한 선호의식 데이터를 수집한다. 마지막으로 선호도 분석을 통해 공유형 개인이동장치 이용 자가 선호하는 설계요소를 도출한다. 본 연구의 결과는 다음과 같다. 공유형 개인이동장치 주차공간/면에 대한 설계요소로 주차면, 주 차각도 및 방향, 주차방법을 도출하였다. 공유형 개인이동장치 주차공간/면 설계요소를 바탕으로 16개의 설계대안을 도출하였다. 공유 형 개인이동장치 주차공간/면 설계대안에 대한 이용자의 선호도를 분석하였다. 이를 바탕으로 공유형 개인이동장치 이용자의 특성 및 이용행태별로 선호하는 설계요소를 도출하였다. 본 연구의 연구결과를 바탕으로 공유형 개인이동장치 주차공간/면 설계대안에 대한 기 준 마련을 위한 기초자료를 제시하였다.

The diversity of smart EV(electric vehicle)-related industries is increasing due to the growth of battery-based eco-friendly electric vehicle component material technology, and labor-intensive industries such as logistics, manufacturing, food, agriculture, and service have invested in and studied automation for a long time. Accordingly, various types of robots such as autonomous mobile robots and collaborative robots are being utilized for each process to improve industrial engineering such as optimization, productivity management, and work management. The technology that should accompany this unmanned automobile industry is unmanned automatic charging technology, and if autonomous mobile robots are manually charged, the utility of autonomous mobile robots will not be maximized. In this paper, we conducted a study on the technology of unmanned charging of autonomous mobile robots using charging terminal docking and undocking technology using an unmanned charging system composed of hardware such as a monocular camera, multi-joint robot, gripper, and server. In an experiment to evaluate the performance of the system, the average charging terminal recognition rate was 98%, and the average charging terminal recognition speed was 0.0099 seconds. In addition, an experiment was conducted to evaluate the docking and undocking success rate of the charging terminal, and the experimental results showed an average success rate of 99%.

이 연구의 목적은 청년층의 이동이 인구 재분포에 미치는 영향을 분석하는 것이다. 이를 위해 청년층의 이동을 대학 진학과 취업 목적으로 구분하고, 다양한 스케일에서 조이동강도와 인구이동 유효도 지수를 산출하였다. 주요 연구 결과는 다음과 같다. 첫째, 대학 진학 관련 이동은 시군구뿐만 아니라 모든 스케일에서 인구 재분포에 상당히 큰 역할을 하고 있었다. 둘째, 취업 이동은 특정 권역에 집중되는 경향이 있었고, 이동 범위도 대학 진학을 위한 이동에 비해 상대적으로 좁은 범위에 국한되어 나타났다. 셋째, 청년층의 대학 및 취업을 위한 이동의 영향력은 성별에 따라 편차가 존재하였다. 넷째, 성비를 사례로 탐색한 결과 한 지역의 인구학적 결과는 청년층의 인구이동과 밀접한 관련성이 있는 것으로 판단된다. 본 연구의 결과는 향후 우리나라의 지역별 인구문제 진단 및 대응책 마련에 중요한 시사점을 제공한다.

The primary focus in the nuclear power market revolves around the advancement of small modular reactors (SMRs) featuring fourth-generation nuclear technology. Microreactors, a subset of SMRs, are characterized by their portability due to their very small size. Despite the accelerated development of microreactors, there are currently no regulations concerning their transportation. To pave the way for future regulatory requirements, existing laws and standards were initially examined. This included a review of basic standards, special conditions of the Road Traffic Act, road transport regulations for nuclear material shipments, and physical protection regulations. Additionally, summaries were provided for design standards related to acceleration loads and vibration tests during road transport and land-based nuclear power plant designs. The anticipated outcome of this study is comprehensive coverage of considerations for designing a transport system for micro-nuclear reactors, providing developers the flexibility to selectively apply them to their specific needs. Furthermore, it is anticipated that this information can serve as fundamental data for establishing licensing requirements in the future.

PURPOSES : This study investigates the effects of three different three-color arrow traffic light operations on right-turn vehicles at intersections in Busan Metropolitan City. METHODS : Intersections in this study were categorized as general intersections (Type 1), intersections with right-turn pockets (Type 2), and intersections with scramble crosswalks (Type 3), and were investigated in terms of the efficiency (i.e., control delay) and safety (i.e., number of conflicts) of right-turn vehicles by employing VISSIM 2023 and SSAM3. RESULTS : From a mobility perspective (i.e., control delay), the protected/permitted operation outperformed the other two methods at the three types of intersections. The protected operation, similar to the results of the protected/permitted operation, was also superior to the permitted operation in terms of safety (i.e., number of conflicts). CONCLUSIONS : Protected/permitted operation has been proven to be a more efficient and safer measure than other operation methods for alleviating the problems of protected right-turn operation, which is currently implemented without three-color arrow traffic lights.

PURPOSES : We propose a framework to evaluate the reliability of integrating homogeneous or heterogeneous mobility data to produce the various data required for greenhouse gas emission estimation. METHODS : The mobility data used in the framework were collected at a fixed time from a specific point and were based on raster data. In general, the traffic volume for all traffic measurement points over 24 h can be considered raster data. In the future, the proposed framework can be applied to specific road points or road sections, depending on the presence or absence of raster data. RESULTS : The activity data required to calculate greenhouse gas emissions were derived from the mobility data analysis. With recent developments in information, communication, and artificial intelligence technologies, mobility data collected from different sources with the same collection purpose can be integrated to increase the reliability and accuracy of previously unknown or inaccurate information. CONCLUSIONS : This study will help assess the reliability of mobility data fusion as it is collected on the road, and will ultimately lead to more accurate estimates of greenhouse gas emissions.

본 연구의 목적은 보행로의 완충공간에 설치할 공유형 개인이동장치 주차구획을 합리적으로 설계하는 것이다. 공유형 개인이동장치 주차구획 설계를 위해 공유형 개인이동장치 주차구획의 주차형식별 규격과 주차용량을 산정하는 공식을 도출하였다. 본 연구의 방법 은 다음과 같다. 먼저 보행로 완충공간의 수직길이에 대한 기하학적 특성을 활용하는 것이다. 이를 바탕으로 공유형 개인이동장치 주 차구획의 수직길이에 대한 제약조건을 도출하였다. 다음으로 보행로 완충공간의 수평길이에 대한 기하학적 특성을 활용하는 것이다. 이를 바탕으로 공유형 개인이동장치 주차구획의 수평길이에 대한 제약조건을 도출하였다. 본 연구의 결과는 다음과 같다. 보행로 완충 공간의 수직길이에 대한 공유형 개인이동장치 주차구획의 주차형식별 규격을 바탕으로 주차구획 설계공식을 도출하였다. 보행로 완충 공간의 수평길이에 대한 공유형 개인이동장치 주차구획의 용량을 바탕으로 주차구획 설계공식을 도출하였다. 본 연구는 연구결과를 바탕으로 보행로의 완충공간에 설치할 공유형 개인이동장치 주차구획에 대해 최적의 주차형식과 주차용량을 도출하였다.

본 연구는 8월에 한반도를 우회하며 동해상으로 빠져나간 2018년 제 19호 태풍 Soulik과 서해상으로 북진하여 통과한 2020년 제 8호 태풍 Bavi을 통해 태풍 유입 전‧후에 따른 한반도 해역별 수온 변동성을 분석하였다. 분석자료는 국립수산과학원 실시간 수온 자료와 수온관측소 근처 AWS의 바람자료 및 NOAA/AVHRR 위성 수온자료를 활용하였다. 분석 결과 이동경로가 다른 태풍이 한반도를 통과할때 동해에서는 풍속과 풍향에 따라 수온의 상승(북풍)과 하강(남풍)이 반복적으로 발생하였는데 특히 태풍 Soulik 유입 시 10 ℃ 안팎의 급격 한 수온 하강을 보였다. 서해는 태풍 Bavi의 중심부가 통과되면서 서해 일부 해역에서 수온이 상승되었고, 차가운 물덩어리가 존재했던 남 해 일부 해역에서도 태풍 Bavi의 이동으로 따뜻한 수온이 유입되어 평년 수온으로 회복된 것으로 나타났다. 또한 태풍 유입시 서해와 남해 는 지형적‧환경적 조건으로 인해 각 해역별 특성에 맞게 수온 변동이 다르게 나타났다. 본 연구를 통해 태풍으로 인한 한반도 해역별 수 온 변동을 해석함으로써 이상기후에 따른 양식 생물의 부정적인 영향을 최소화하고 해역별 수산재해의 피해대응 전략을 수립하는데 기여 할 것으로 사료된다.

In this study, we have developed a movable defect detection system based on a vision module with machine-learning algorithm for distinguishing product quality. Machine-learning model determined the results in good or no good through images acquired from the vision module consisting of a camera, processor unit, and lighting. To ensure versatility for use in a variety of settings, we have integrated a robot arm and cart for the movable defect detection system, and the robot arm that adjusts the focus length is made to be able to rotate in all directions. The type of defect was divided into eccentricity defect and printing defect. As a result, it was confirmed that classification accuracy showed 0.9901 in our developed device.

PURPOSES : This study is to analyze factors affecting improper parking behaviors in a perspective of personal mobility users. Detailed purposes are as follows. Firstly, exogenous and endogenous latent variables were set. Secondly, structural equation model were constructed. Hypothesis for the structural equation model were established. Then model’s goodness of fit was analyzed and following the result model was modified. Lastly, factors affecting improper personal mobility parking behavior was found out. METHODS : Based on the literature review, exogenous and endogenous latent variables were set. Correlation between latent variables and their observed variables was defined to build structural equation model. According to the model hypothesis was established. In order to collect data, survey was conducted on personal mobility users. Model’s goodness fit was verified and the model was modified. Lastly in order to find out the factors affecting improper personal mobility parking behavior path analysis was conducted. RESULTS : Based on literature review, based on 6 of latent variables the structural equation model was made. Survey was conducted on 341 participants who has used personal mobility at least once based on Likert 5-point scale. Out of 341 responses 22 responses considered as careless responses were removed. As a result of analysis of structural equation model, it turned out that ‘ease of transfer’ had a positive effect on improper parking of personal mobility meanwhile ‘convenience’ and ‘road condition’ had a negative effect. CONCLUSIONS : It was concluded that the proximity and accessibility to the transfer facility could be important when installing personal mobility parking lot as improper parking behavior of personal mobility users could be affected by ease of transfer to other traffic mode. Also, interval of parking lots, location and its road condition should be considered in order to make it convenient for users to find parking lot and to encourage them to use it more often.

PURPOSES : This study is to analyze preference of shared personal mobility(shared e-scooter or shared bike) parking lot. The detailed purposes are as follows. Firstly, the attributes and attribute levels of shared personal mobility are developed. Based on combined attributes and attribute levels several profiles were composed. Preference data of shared personal mobility parking lot is collected through survey. Preference of shared personal mobility parking lot was analyzed using conjoint analysis. METHODS : Based on the literature review, the attributes and attribute levels that might affect behavior or intention of shared personal mobility parking were developed. Several profiles that contain combined attributes and attribute levels were created in a fractional factorial design. In order to collect preference data of shared personal mobility parking lot, online survey were proceeded. The survey participants were asked to mark preference point between point 1 and point 10. Lastly, preference of shared personal mobility parking lot was analyzed using conjoint analysis. RESULTS : Based on literature review, 5 attributes for conjoint analysis were set.(Distance between shared personal mobility parking lot and destination, Space for shared personal mobility parking lot, Location of shared personal mobility parking lot, Type of shared personal mobility parking lot, Interval of shared personal mobility parking lot). With the combination of 5 attributes and their levels, 16 random profiles were made. Online survey was proceeded with 300 participants who have used shared personal mobility. Using conjoint analysis utility and importance of each attribute has been calculated. As a result, the preference got higher when distance between parking lot and destination and intervals of parking lots are short. In addition racks are tended to be preferred and it seems to be more profer to install parking lot on buffer zone of pedestrian road instead of adjacent to private building. CONCLUSIONS : It could be important to install personal mobility parking lot considering preference of parking lot attributes in order to encourage users to use the proper parking lot instead of parking anywhere.