三菱扶桑卡客車有限公司

This paper presents the design and implementation of a Semi-Autonomous Light Commercial Vehicle (LCV) capable of following a person while performing obstacle avoidance in urban and controlled environments. The LCV leverages its onboard 360-degree view camera, RTK-GNSS, Ultrasonic sensors, and algorithms to independently navigate the environment, avoiding obstacles and maintaining a safe distance from the person it is following. The path planning algorithm described here generates a secondary lateral path originating from the primary driving path to navigate around static obstacles. A Behavior Planner is utilized to decide when to generate the path and avoid obstacles. The primary objective is to ensure safe navigation in environments where static obstacles are prevalent. The LCV's path tracking is achieved using a combination of Pure Pursuit and Proportional-Integral (PI) controllers. The Pure Pursuit controller is utilized as lateral control to follow the generated path, ensuring smooth and accurate path tracking. Additionally, a PI controller is utilized for speed control, maintaining a consistent and safe speed. Multiple tests were conducted in various urban and controlled environments, especially densely-parked city roads, ramps, residential streets to evaluate the LCV's performance. The results demonstrate the LCV's ability to safely avoid parked vehicles showing human-like decision making and motion control, also maintaining a consistent following distance with the lead-person. The solution focuses on slow-speed applications where precision is of utmost priority. Additionally, the application of ultrasonic sensors helped in achieving immediate stops in close proximity scenarios. This system has significant potential for applications in last-mile delivery, logistics, waste management, and urban mobility, offering a versatile solution for safe and efficient navigation in complex environments and narrow roads.

This study presents a structured approach to the aerodynamic evaluation of commercial heavy-duty vehicles by categorizing the underlying flow physics into three primary phenomena: pressure-induced separation, geometry-induced separation, and flow diffusion. Furthermore, the study gives insights into the benefits of Detached Eddy Simulations (DES) over traditional Reynolds-Averaged Navier–Stokes (RANS) approaches by analyzing the flow behavior in cases that correspond to these phenomena. Fundamental insights on pressure and geometry-induced separation were developed through simulations of flow over a sphere and a rectangular cylinder at a Reynolds number of 2.8 × 106. Additionally, flow diffusion was investigated using a coaxial jet interacting with surrounding fluid at a Reynolds number of 2.1 × 104. These cases were analyzed using three turbulence modeling techniques: k-ε, k-ω SST, and DES. To demonstrate the practical relevance of these phenomena, a comprehensive aerodynamic performance study was conducted on a commercial heavy-duty truck. This final analysis integrates all three flow behaviors, showcasing their combined impact on vehicle aerodynamics. The study emphasizes the effectiveness of the DES approach in capturing complex flow structures with enhanced accuracy. Furthermore, this study provides meshing guidelines for near-wall and wake dominant regions, to be implemented in DES-based simulations. The findings aim to support future research by offering a robust framework for applying advanced turbulence models in real-world aerodynamic evaluations.

AIMS:This study examined whether or not the coexistence of smoking and metabolic syndrome synergistically increases the risk of cardiovascular disease (CVD) beyond their individual effects. METHODS:This prospective cohort study included 68,743 workers from the Japan Epidemiology Collaboration on Occupational Health Study. The participants were categorized into four groups based on their smoking status and metabolic syndrome. Biological interactions were evaluated using relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy index (S). RESULTS:During a mean follow-up of 7.2 (range: 0.1-10.9) years, 346 participants developed CVD. Current smokers with metabolic syndrome had the highest CVD risk (hazard ratio: 6.45, 95% confidence interval [CI]: 4.73-8.80). Approximately 35% of CVD cases among individuals exposed to both factors were attributed to their biological interactions (RERI: 2.27, 95% CI: 0.56-3.98; AP: 0.35, 95% CI: 0.15-0.55; S: 1.71, 95% CI: 1.16-2.52). An analysis of CVD subtypes revealed a significant biological interaction for myocardial infarction (RERI: 5.14, 95% CI: 0.65-9.62; AP: 0.52, 95% CI: 0.26-0.78; S: 2.38, 95% CI: 1.22-4.62) but not for stroke (RERI: 1.34, 95% CI: -0.46-3.13; AP: 0.25, 95% CI: -0.03-0.53; S: 1.44, 95% CI: 0.89-2.34). CONCLUSION:Smoking and metabolic syndrome interact synergistically to elevate CVD risk, particularly for myocardial infarction. Targeting both factors is essential for CVD prevention.

BACKGROUND:Long-term sickness absence (LTSA) is an important public health challenge, yet limited data exist on its incidence in Japan. We aimed to describe the incidence of all-cause and cause-specific LTSA by sex and age using 10-year data from a large Japanese working population, with a focus on sex differences. METHODS:The study participants were employees from 16 worksites in the Japan Epidemiology Collaboration on Occupational Health Study between April 2012 and March 2022. LTSA, defined as sickness absence from work lasting 30 days or more, was recorded at each worksite. The causes of LTSA were classified using the International Classification of Diseases, 10th Revision. Incidence rates for all-cause and cause-specific LTSA were calculated based on sex and age. RESULTS:During 730,391 and 161,513 person-years of follow-up, 6,518 and 1,866 spells of LTSA were recorded in males and females, respectively. Females had higher incidence rates of all-cause LTSA than males (115.5 vs 89.2 per 10,000 person-years), especially among females in their 20s and 30s. This was partly attributed to younger females experiencing higher LTSA incidence rates due to mental disorders, neoplasms, and pregnancy-related illnesses. In older age, females had higher LTSA incidence rates than males for musculoskeletal diseases and injuries/external causes, whereas LTSA incidence rates due to circulatory diseases were lower than those in males. CONCLUSION:The incidence of total and cause-specific LTSA varied greatly by sex and age, highlighting the need to consider employees' characteristics in the prevention and management of LTSA.