• International conference on construction engineering and project management
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• 2022.06a
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• pp.678-685
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• 2022

Prefabrication is a construction technique that is increasingly being applied to different building components due to its many benefits, including higher quality and lower waste. Despite these advantages, there are challenges in execution of these components on projects, due to transportation logistics, skilled labor requirements, and project management techniques. This paper investigates the current landscape of prefabricated pipe spools and potential solutions for minimizing these challenges. The scope of this research includes a proposed workflow, to standardize implementation of these components. Semi-structured interviews were conducted with industry professionals to assess current industry practices and the validity of the proposed workflow. Findings of this paper indicate that greater integration between design, fabrication and transportation is required to minimize inefficiencies when implementing prefabricated pipe spools on projects.

• Journal of Korean Society of Transportation
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• v.11 no.3
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• pp.49-66
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• 1993

The successful management of logistics in an organization requires the careful coordination and manipulation of both movement and storage. In this study, we can show what is the most efficient and the cheapest method to transport the petroleum products under a few constraints with the model of linear programming. And also, the model can give some important informations so as what is the best coverages of each terminals by types, how many products should be exchanged among each companies and which terminals or complexes are economically prior to the others. Even we can understand that the duality is one of the useful measures to evaluate the economical efficiencies of transportation and storage related elements such as complex and terminal location, transport mode, storage tankage capacity and in/outflow facilities of terminals etc.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.393-396
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• 2005

Due to the fast growing rate of the global container trade, every major port is under the pressure of meeting the projected capacity demand. As a result, alternative solutions have been sought for improving capacity and meeting the growing demand for container storage area and terminal capacity. Moreover, material handling process re-engineering is now a critical issue for logistics and supply chain managers of airline, shipping lines, terminal and warehousing enterprises around the world. Therefore, the purpose of this paper is to develop the 3D simulator for executing performance valuation of port transportation systems. The developed 3D simulator system is to measure the effectiveness of the proposed total system and compare it with existing practices. The performance analysis variables are also defined for these comparisons

• Management Science and Financial Engineering
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• v.8 no.2
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• pp.33-45
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• 2002

This study suggests an approach for determining fleet size for LTL (less -than-truckload) transportation with dynamic demand for on-time supply of the parts between the assembly line in an automobile company and its part suppliers in Korea. The vehicles operated by the transportation trucking companies in Korea in general can be classified into three types depending on the ways how their expenses occur; company -owned truck, mandated truck which is owned by outsider who entrusts the company with its operation, and rented truck (outsourcing) . With the forecasted monthly production data a year, a heuristic algorithm is developed to determine the number of company-owned trucks, mandated trucks, and rented trucks in order to minimize the expected annual operating cost, which is based on the solution technologies used in the aggregate production planning and vehicle routing problem. Finally the algorithm is tested for the problem how the trucking company transports parts for the automobile company.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.159-166
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• 2012

Recently, by the whole world paradigm shift to "Low Carbon Green Growth", it is required to renovate National Transportation and Logistics System. Transportation accounts for 21% of the total energy consumption and 20% of the total $CO_2$ emission, and also places its main reliance on fossil fuels. From green point of view, electric railway system is superior to the other transportation alternatives, but also required to develop the innovative technologies for high efficiency and low energy consumption. In this paper, the concept of railway green operation system by regenerative synchronized driving is presented, including the numerical example and the estimated effect.

• Journal of the Korean Society of Safety
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• v.39 no.1
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• pp.55-61
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• 2024

In response to the COVID-19 pandemic, the logistics industry in Korea has rapidly been expanding, with offline demand concentrating on online platforms owing to the development of digital infrastructure. This has increased the workload of courier drivers considerably, along with labor intensity. A delivery driver died recently from overwork due to the continuous increase in delivery volume, which raises social concerns. Delivery drivers work long hours, (over 12 hours) and are greatly affected by weather conditions, such as snow, rain, heat waves, and cold waves. In addition, they lack a fixed workplace; perform atypical work handling workpieces of various sizes, weights, and shapes; and spend a large amount of time driving as part of their work. This work involves a high level of tension and requires attention and concentration. Despite the frequency of industrial accidents in the courier industry, studies on safety and health to quantitatively analyze and systematize the work of courier workers are very scarce. Therefore, to define the work process necessary for investigating the harmful factors in delivery service and the work analysis, this study conducted interviews and on-site surveys to analyze the unit work of the delivery service by targeting delivery workers. In other words, a framework of unit work for work analysis was presented to enable research and analysis by considering the aforementioned characteristics of the courier industry. The process was broadly divided into work, transport, storage, delay, and inspection. Work was divided into loading, sorting, unloading, and door subcategories, and transportation was divided into vehicle, cart, and walking subcategories as well as 10 small processes. Moreover, 22 unit works were again drawn by conducting field surveys and interviews. The risk of unit work derived from this study was ergonomically evaluated, and the ergonomic analysis revealed that uploading and transportation were the most dangerous. The results of this study could be used as basic data for preventing industrial accidents among courier workers, whose work has increased with the logistics volume and the development of the logistics industry.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.2
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• pp.74-88
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• 2020

A Cooperative Intelligent Transportation System (CITS) provides useful information on upcoming hazards in order to prevent vehicle collisions. In addition, the availability of individual vehicle travel information obtained from the CITS infrastructure allows us to identify the level of road safety in real time and based on analysis of the indicators representing the crash potential. This study proposes a methodology to derive road safety content, and presents evaluation results for its applicability in practice, based on simulation experiments. Both jerk and Stopping Distance Index (SDI) were adopted as safety indicators and were further applied to derive road section safety information. Microscopic simulation results with VISSIM show that 5% and 20% samples of jerk and SDI are sufficient to represent road safety characteristics for all vehicles. It is expected that the outcome of this study will be fundamental to developing a novel and valuable system to monitor the level of road safety in real time.

• Journal of the Korea Safety Management & Science
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• v.12 no.3
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• pp.315-320
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• 2010

Recently, there are environmental issues for sustainable transportation system to pursue the energy-efficient and environment-friendly public urban transit. These transportation system needs to offer demand-oriented high-quality service being on the same level with cab service for urban space. PRT(Personal Rapid Transit), small track-guided vehicle, is repeatedly mentioned as a possible alternative for the new urban public transportion system, but but there are not many researches on the operational optimal routing for PRT network. In this paper, the concept of PRT and general optimal routing methods are reviewed. And we suggest the optimal routing method for city-wide PRT network with multi-vehicles and stations, junctions and directional arcs. Futher research directions for PRT routing are presented.

• Journal of Korean Society of Transportation
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• v.27 no.1
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• pp.129-141
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• 2009

Intermodal freight transportation is defined as the movement of freight from origins to destinations by two or more transportation modes. When implemented in hub networks, it could enhance the efficiency of the networks because consolidated flows are transported by more suitable modes and technologies. In spite of this advantage, the intermodal hub network design problem has received limited attention in the literature partly because of the complex nature of the problem. This paper aims to develop an optimization model for designing intermodal hub networks with sin91e allocation strategy. The model takes into account various cost components of intermodal hub networks including transportation, stationary inventory, and service delay costs. Moreover, using transport frequency variables, it is capable of endogenously determining the transportation economies of scale achieved by consolidation of flows. As such, the model is able to realistically represent the characteristics of intermodal hub networks in practice. Since the model Is a complicated nonlinear integer programming problem, we perform model simplification based on the analytical study of the model, which could facilitate the development of solution algorithms in the future. We expect that this study contributes to the design of intermodal hub networks as well as to the assessment of existing logistics systems.

• Journal of Korean Society of Transportation
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• v.19 no.6
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• pp.49-63
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• 2001

The pattern of urban transport activity has two major components: the movement of people and the movement of goods. Roads in urban areas carry large number of trucks laden with goods that support urban economy and lifestyle. Therefore urban goods movement plays a vital role, but at the same time, urban goods movement are an important source of congestion, and a major contributor to the adverse environmental and social impacts of urban transport. In addition, the demand for goods movement is growing at a faster rate than personal travel in many cities, due to changes in industry logistics and consumer purchasing patterns. As a result, the significance of urban freight activity is increasing in terms of both its role in urban economy and its adverse impacts on urban amenity. This study is focused on the role and involvement scope of metropolitan government in urban logistics aimed at increasing its efficiency and reducing its negative impacts. The major suggestions of this study are (a) development of a measure of urban goods movement activity, (b) evaluation of data requirements and availability, (c) dialogue between the public sector and private sector, and (d) the role of metropolitan government.