• Advances in aircraft and spacecraft science
• /
• v.10 no.6
• /
• pp.495-519
• /
• 2023

The drone serves the customers not served by vans. At the same time, considering the safety, policy and terrain as well as the need to replace the battery, the drone needs to be transported by truck to the identified station along with the parcel. From each such station, the drone serves a subset of customers according to a direct assignment pattern, i.e., every time the drone is launched, it serves one demand node and returns to the station to collect another parcel. Similarly, the truck is used to transport the drone and cargo between stations. This is somewhat different from the research of other scholars. In terms of the joint distribution of the drone and road vehicle, most scholars will choose the combination of two transportation tools, while we use three. The drone and vans are responsible for distribution services, and the trucks are responsible for transporting the goods and drone to the station. The goal is to optimize the total delivery cost which includes the transportation costs for the vans and the delivery cost for the drone. A fixed cost is also considered for each drone parking site corresponding to the cost of positioning the drone and using the drone station. A discrete optimization model is presented for the problem in addition to a two-phase heuristic algorithm. The results of a series of computational tests performed to assess the applicability of the model and the efficiency of the heuristic are reported. The results obtained show that nearly 10% of the cost can be saved by combining the traditional delivery mode with the use of a drone and drone stations.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.5
• /
• pp.481-489
• /
• 2017

The study area,Cheonan Stream, is an urban river that flows through urban areas in close proximity to densely populated areas and multi-use facilities. The natural river improvement project from 2006 to 2015 improved the quality of life of local residents with the improvement of river function, the restoration of the natural ecosystem and the securement of hydrophilic space. A bike way in the constructed waterside space was built focusing on trails. This study suggests improvements appropriate for insufficient bike way function-related regulations. The problems of ramps, river crossing facilities, stairway facilities, safety facilities, signs, road markings, and parking facilities, etc.have arisen in the utilization situation and citizen consciousness survey. As an improvement, it was suggested that 12% or fewer ramps should be improved, a submerged bridge should be installed at 7 places separated by stepping bridges, and signs and road markings according to bike way-related regulations should be installed and bike parking facilities at Cheonan station and Cheonan bus terminal should be expanded. The bike way in the waterfront of ChoenanCheon(river) will increase the accessibility and utilization rate of short-distance transportation with the institutional expansion of bike use facilities and work organizations and the improvement of facilities in accordance with urban rivers and bike-related regulations. Therefore, it is expected that the development of the living space will be beneficial for the citizens due to the elimination of traffic in the city and the activation of bike traffic.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.21 no.6
• /
• pp.185-195
• /
• 2017

In recent years, unexpected bridge fire accidents have increased because of augmenting the number of traffic volumes and hazardous materials by the increment in traffics and distribution business. Furthermore, in accordance with the effort of using the under space of bridges, the ratio of occupied by combustible materials like oil tanker or lorry has been increased. As a result, the occurrence of bridge fire has been growing drastically. In order to mitigate the accident of bridge fire, risk assessment of bridge fire has been studied, however, practical risk models considering safety from users' viewpoints were scarce. This study represented quantitative risk assessment model applicable to national road bridges in Korea. The primary factors with significant impacts on bridge fire accidents was chosen such as clearance height, materials of bridges, arrival time of fire truck and fire intensity. The selected factors were used for Fire Dynamics Simulation (FDS) and the peak temperature calculated by FDS in accordance with the fire duration and fire intensity. The risk assessment model in bridge fire reflected the FDS analysis results, the fire damage criteria, and the grade of fire truck arrival time was established. Response plans for bridge fire accidents according to the risk assessment output has been discussed. Lastly, distances between bridges and fire stations were calculated by GIS network analysis. Based on the suggested assessment model and methodology, sample bridges were selected and graded for the risk assessment.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.10 no.1
• /
• pp.74-92
• /
• 2000

This study was performed to evaluate the working conditions In construction workers through measurements of working environments and to improve the working conditions and to design the appropriate environmental and health management system. The results of measurement for working environments in construction work are as following: 1. The excess rate of noise and dust concentration in express highway construction, road construction, building construction and interior painting was 28.6% and 24.5% respectively. 2. The excess rate of mixed organic solvents concentration in interior painting was 39.3%. 3. The chain type bulldozer has the highest level of vibration; the excess rate was 85.7%, and among the vibration instruments, the level of left hand's vibration of all vibrators exceeded the criterion and in the case of drilling all the level of vibration exceeded the criterion in both hands. On the basis of the results in this research the environmental and health management system for construction workers must be considered. Therefore, it is necessary to be introduced the special medical examination and measurement of working environments in construction industry. In defining "the working place" of Article 39 of Enforcement regulations of industrial safety and health act, the word "indoors" should be deleted. Then the eligible industry for measurement of working environment must be extended. And it is also necessary for construction industry to be performed group health management service by agencies such as other manufacturing industry.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.17 no.3
• /
• pp.59-71
• /
• 2018

This study was initiated to develop an optimal signal control algorithm for coordinated signalized intersections using individual vehicle's information which can be collected in a format of prove vehicle data (PVD) via V2I (Vehicle to Infrastructure) communication environment. For developing this signal optimization algorithm, three modules were developed for phase group length computation, split distribution, and phase sequence assignment. The simulation analysis using the microscopic simulation model, Vissim, was conducted for evaluating the effectiveness of the developed algorithm. The analysis result represented that the performance of the developed algorithm is far superior to that of the fixed coordinated signal control method which is the most common signal control method for coordinated signalized intersections in Korea.

• Journal of the Society of Disaster Information
• /
• v.16 no.3
• /
• pp.458-471
• /
• 2020

Purpose: In Korea, the frequency and frequency of earthquakes are increasing every year. Therefore, the purpose of this study was to compare and analyze the characteristics and examples of earthquakes in Korea and Japan, and to propose improvements to the earthquake prevention policy in Korea. Method: In this study, we investigate and evaluate Japan's response in two cases: the Kobe earthquake and the East Japan earthquake. After surveying and evaluating the nation's countermeasures in the two events, Gyeongju and Pohang, they were compared. Result: When comparing recovery systems in Korea and Japan, there were significant differences in plans for restoration of road transport networks, regional disaster prevention plans, and the introduction of Conclusion: considering the physical distance between Korea's earthquake-prone areas and the capital, the government should quickly come up with countermeasures to ensure that immediate earthquake response in the region is enhanced through the detailed establishment of the Functional Continuity Plan (COOP), and that administrative functions will function normally in the event of a disaster through the introduction of the administrative BCP concept.

• Journal of the Ergonomics Society of Korea
• /
• v.35 no.5
• /
• pp.465-472
• /
• 2016

Objective:This study is on the characteristics of motorcycle accidents occurring in the mail delivery process by skill level. Background: The tendency of delivery postmen's driving in a hurry may become the cause of accidents since there is a constraint that delivery should be completed within a limited time. Method: This study analyzed the traffic accident data of 259 delivery postmen, who had been approved as occupation-related industrial accident victims from 2009 to 2012, by their work experience in view of season, day of the week of an accident occurrence, accident occurrence time, accident cause, collision type, and driving situation. Results: Accident characteristics of delivery postmen show that the ratio of accidents occurring to those who had less than 10 years of work experience was high. There were many motorcycle collisions in winter and summer by season and an unexpected object, along with road condition, took up 70.7% of the accident sources. There were no differences in accident occurrence time, the day of the week, season, accident source, and collision type between the group of delivery postmen with less than 10 years of work experience and those with 10 years or more of work experience. However, there was a difference in distribution of driving condition. Conclusion and Applications: The results of this study can be used to present the policies or guidelines for the accident prevention of delivery postmen since the results show the characteristics of the injured and accident occurrence characteristics in relation with the delivery postmen's motorcycle collisions.

• Journal of Korean Society of Disaster and Security
• /
• v.13 no.1
• /
• pp.51-58
• /
• 2020

This paper analyzes the effect of airflow of ceiling air conditioner on the operation of sprinkler head using a simulation program. The simulation space is 10 m × 7 m × 3 m, and the size of the fire is 0.8 m × 0.8 m × 0.6 m. The cold air flow from the air conditioner is at 25℃ and the wind speed is divided into three cases : 10 ㎧, 8.5 ㎧, and 7.5 ㎧. Simulation results show that all cases had operating delays compared to when the air conditioner was not running, and the sprinkler head did not operate until 10 minutes had elapsed at 10 ㎧ wind speed. These results confirmed that the sprinkler head was delayed in the air conditioning space and the worst result of early evolution failure was observed in strong winds such as 10 ㎧.

• Archives of Craniofacial Surgery
• /
• v.20 no.4
• /
• pp.228-232
• /
• 2019

Background: The epidemiology of nasal fractures varies according to factors such as the era and area of the study, as well as the age of the patient. We compared the characteristics and causes of pediatric nasal fractures. Methods: A total of 2,321 patients with nasal fractures from 2010 to 2017 were examined. The patients were divided into age groups using the Korean school system of age classification. The causes of injury were divided into five groups: violence, fall or slip down, sports, road traffic accidents, and others. Fractures were classified using the Stranc and Robertson standard: vector of force and plane of fracture. Results: Violence was the most common cause of nasal fracture in patients older than 12 years. Violence was a significantly less frequent cause among patients younger than 12 years old than among adolescent and adult patients. Nasal fractures due to violence were not observed in patients younger than 10 years. Plane 2 and lateral force fractures were the most common; however, in patients younger than 12 years, frontal force fractures were significantly more frequent than were lateral force fractures. Conclusion: As children may simply be injured due to a fall or slip down, it is important for the parents and guardians to ensure their safety. As they become older, children should abstain from violence and be monitored. It is therefore very important to ensure that the environment is free of violence in order to prevent such injuries.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.6
• /
• pp.117-122
• /
• 2022

In this paper, we developed a vehicle control terminal using IoT and low-power long-distance communication (NB-IoT) technology. This system collects information on the location and status of a parked vehicle, and transmits the vehicle status to the vehicle owner's terminal in real time with low power to prevent vehicle theft, and in the case of a vehicle in motion, When primary information about the vehicle, such as an impact, is collected and transmitted to the server, the server analyzes the relevant data to generate secondary information on traffic congestion, road damage, and safety accidents. By sending it, you can know the exact arrival time of the vehicle at its destination. This terminal device is an IoT gateway for a vehicle and can be connected to various wired and wireless sensors inside the vehicle. In addition, the data collected from vehicle maintenance, efficient operation, and vehicles can be usefully used in the private or public sector.