• Annals of Occupational and Environmental Medicine
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• v.34
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• pp.39.1-39.11
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• 2022

Background: Workers in logistics centers are always pressed for time to collect and pack products. They also participate in high-intensity manual labor in which various musculoskeletal hazards exist. In the case of logistic center labor, it is estimated that there is a high risk of presenteeism due to the above characteristics which can cause deterioration of workers' mental health. However, there is insufficient research on this topic. Methods: Workers in a logistic center were surveyed using an Internet questionnaire. The survey items included demographic characteristics, labor intensity and work-related factors, and mental health aspects such as depression and anxiety. The survey was conducted for about a month from July 26, 2021 and a total of 353 people were analyzed. Through the χ² test and t-test, the characteristics of workers who experienced presenteeism were examined and the prevalence ratios (PRs) of depression and anxiety experiences were calculated by multivariable Poisson regression. Afterwards, stratification analysis considering gender, the type of contract, and labor intensity was implemented. Results: In the group that experienced presenteeism, the number of working days per week was higher and fixed-term workers, high labor intensity, and sleep deprivation were more common. In the multi-Poisson regression analysis conducted by adjusting the demographic characteristics, working hours, and work-related factors, the PRs of depression and anxiety were 1.98 (95% confidence interval: 1.24-3.18) and 1.81 (1.22-2.68), respectively. In particular, the p-value for interactions was significant when stratified with the type of contract. Conclusions: As a result of the study, presenteeism and mental health were associated in logistic center workers. To prevent mental health issues of logistic center workers, management of presenteeism is necessary and a prospective study is needed.

• Journal of the Korean earth science society
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• v.33 no.1
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• pp.39-48
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• 2012

In this study, a statistical estimation of probable precipitation and an analysis of its return period in Busan were performed using long-term precipitation data (1973-2007) collected from the Busan Regional Meteorological Administration. These analyses were based on the method of probability weighted moments for parameter estimation, the goodness-of-fit test of chi-square ($x^2$) and the probability plot correlation coefficient (PPCC), and the generalized logistics (GLO) for optimum probability distribution. Moreover, the spatial distributions with the determination of probable precipitation were also investigated using precipitation data observed at 15 Automatic Weather Stations (AWS) in the target area. The return periods for the probable precipitation of 245.2 and 280.6 mm/6 hr with GLO distributions in Busan were estimated to be about 100 and 200 years, respectively. In addition, the high probable precipitation for 1-, 3-, 6-, and 12-hour durations was mostly distributed around Dongrae-gu site, all coastal sites in Busan, Busanjin and Yangsan sites, and the southeastern coastal and Ungsang sites, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.94-101
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• 2016

With increasing global concerns for environmental impacts, efforts have been made to encourage a modal shift from road freight to an eco-friendly transport system such as rail freight. In Korea, the government has set master plans for a green transport system but has not taken any substantial action to promote rail freight transport. In developing policies and actions to promote rail freight, quantitative studies on environmental impacts among transportation means are essential. This study examined the air pollutant emissions and greenhouse gas (GHG) emissions per unit freight transported by road and rail, respectively. To improve the accuracy, we analyzed emission data and freight transport mileage of rail freight considering diesel locomotives and electric locomotives separately. The results show that unit air pollutant emissions (except SO2) from road freight are about 7~15 times more than those from rail freight. In addition, the GHG emission unit of road freight is about 4 times higher than that of rail freight.

• Journal of Construction Engineering and Project Management
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• v.4 no.2
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• pp.31-40
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• 2014

The management of vehicular supply of "perishable" construction material, such as concrete mixes, faces a series of uncertainties such as weather, daily traffic patterns and accidents. Presented in this paper is a logistics control model for managing a hauling fleet with interrelated processes at both ends and queue capacities. Discrete event simulation is used to model the complex interactions of production units and the randomness of the real world. Two alternative strategies for ready mix concrete delivery, with and without an off-site waiting queue, are studied to compare supply performance. Secondly, the paper discusses the effect of an agent-based GPS tracking system providing real-time travel data that lessens the uncertainty of trucking time. The results show that the combination of GPS information with off-site queuing reduces productivity loss and process wastes of concrete placement as well as the idleness of supply trucks when crew or pump experience an unexpected stoppage.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.174-179
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• 2018

Clithon retropictus has been protected by the Ministry of Environment as an endangered species since 1998 and has been listed on the state red list of endangered species category II. It is viewed as a representative for all endangered species in the northeastern coastal waters of Korea. Most of the habitats of C. retropictus have been found to be in an unstable state because of development projects such as road construction, small stream development, irrigation for securing agricultural water, and flood prevention. These habitats are damaged by small stream maintenance projects and development, and the risk of damage is increasing and active efforts are needed in order to protect them. Although the Ministry of Environment is striving to preserve this endangered species, the habitat of C. retropictus is still facing external threats because it spreads to only a small area at high densities. Therefore, in order to protect the habitat of C. retropictus, a level II endangered species, it is urgent to make an effort to minimize habitat damage and to take measures for its protection.

• Journal of Distribution Science
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• v.21 no.5
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• pp.31-41
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• 2023

Purpose: Electric vehicle (EV) technology started in 2015 in Thailand. The Thai Government has indicated that 30% of all cars produced in Thailand by 2025 will be EVs. Using EVs in Thailand will reduce road pollution and increase energy efficiency, especially in major cities. Hence, the adoption of EVs in the country has been promoted. This study pointed out that social influence, facilitating conditions, perceived enjoyment, environmental concern, attitude, and perceived behavioral control are key factors affecting the behavioral intention to adopt EVs among logistic and distribution firms in Thailand. Research design, data, and methodology: 500 top management, middle management and purchasing managers of logistic and distribution firms in Thailand are surveyed. The study employed judgmental, convenience, and snowball sampling. Confirmatory Factor Analysis (CFA) and Structural Equation Model (SEM) are the main statistical tools for data analysis. Results: The results show that all determinants impact customers' willingness to adopt EVs, except perceived enjoyment and environmental control. Conclusions: The study proposes to promote the incentives by decreasing electricity prices and endorsing EVs purchase to accelerate the adoption of EVs in Thailand. Therefore, future policies should focus on behavioral intention toward EVs amongst logistic and distribution firms for enhancing the future of mobility in Thailand.

• Journal of Korean Society of Transportation
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• v.34 no.6
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• pp.548-559
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• 2016

Recent interests in both vehicle emissions and public health have facilitated the development of more eco-friendly transportation systems. This study proposed an integrated simulation approach for evaluating the effectiveness of speed management strategies from the various perspectives including safety, operational efficiency, and environmental compatability. Those simulation methods include driving simulation, traffic flow simulation, emissions simulation, and air dispersion simulation. An essence of the proposed simulation framework is to create the systematic connection of each simulation method toward the evaluation of effectiveness of speed management strategies. As an example, chicane and speed hump in residential area were evaluated by the proposed method. It is expected that the proposed simulation-based approach would be effectively used for the decision-making process in selecting better alternatives considering both safety and public health.

• Journal of Korea Port Economic Association
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• v.23 no.4
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• pp.244-265
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• 2007

This study suggested the following several possible ways to develop Busan New Port as a comprehensive port area which comprises logistics functions, water front(for relaxation and leisure of citizens) and living zone (for dealing with daily works and chores): First, install extra facilities(e.g. plaza or landscape architecture facilities) for environmental cleanup of fishery port in the vicinity of logistic and housing complex. Second, develop water front for better benefits of users. Third, build a water land in leisure facilities for foreign tourists. Fourth, build a landmark in Port Hinterland. Finally, develop appropriate esthetic area for Port Logistics Hinterland.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.493-500
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• 2015

The importance of the air and vessel traffic control center is increasing rapidly after the recent accident of 'Sewol ferry'. Aviation, marine, and the logistics sectors are already using monitoring and control technology widely. However, the monitoring and control system for complex and dangerous construction sites operation has yet to be employed. A monitoring/control system is required for effective communication between the control center and the construction equipment fleet at a construction site, and also the exact role that notifies accurate process and identification of hazards on construction sites as needed. Therefore, this paper presents the study about communication between the construction equipment fleet and the control center through the comparison of air traffic, marine, and logistics control systems for the development of construction equipment fleet management system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.53-60
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• 2020

Evaluating the operational efficiency of electric vehicle charging stations (EVCSs) is important to understand charging network evolution and the charging behavior of electric vehicle users. However, aggregation of efficiency performance metrics poses a significant challenge to practitioners and researchers. In general, the operational efficiency of EVCSs can be measured as a complicated function of various factors with multiple criteria. Such a complex aspect of managing EVCSs becomes one of the challenging issues to measure their operational efficiency. Considering the difficulty in the efficiency measurement, this paper suggests a way to measure the operational efficiency of EVCSs based on data envelopment analysis (DEA). The DEA model is formulated as constant returns of output-oriented model with five types of inputs, four of them are the numbers of floating population and nearby charging stations, distance of nearby charging stations and traffic volume as desirable inputs and the other is the traffic speed in congestion as undesirable one. Meanwhile, the output is given by the charging frequency of EVCSs in a day. Using real-world data obtained from reliable sources, we suggest operational efficiencies of EVCSs in Seoul and discuss implications on the development of electric vehicle charging network. The result of efficiency measurement shows that most of EVCSs in Seoul are inefficient, while some districts (Nowon-gu, Dongdaemun-gu, Dongjak-gu, Songpa-gu, Guro-gu) have relatively more efficient EVCSs than the others.