• International conference on construction engineering and project management
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• 2013.01a
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• pp.219-225
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• 2013

State transportation agencies utilize fleets of heavy equipment to construct and maintain roadways. Equipment cost models can be developed to forecast economic life, which is the point at which the average unit cost to date reaches a minimum. A calculated economic life and cost models can be used to quantify the impacts of management strategies applied to a fleet. The purpose of this research was to develop an accurate method of quantifying the results of management strategies applied to a fleet of heavy construction equipment. The strategies evaluated are related to the annual usage of the fleet and the size of the fleet. More specifically the methodology is used to adjust the economic model to consider a limit to the annual decline in machine usage and a reduction in the number of machines in the fleet. When limiting annual machine usage, a specified rate is applied to the usage of the fleet, while total usage is held constant. This causes aging at a modified rate. A reduction in fleet size also causes a change to the usage of a fleet as the fleet must use fewer machines to produce the same total usage.

• Journal of the Korean Institute of Navigation
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• v.23 no.4
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• pp.63-76
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• 1999

This paper aims at developing an integrated fleet management support system for industrial carriers who usually control the vessels of their own or on a time charter to minimize the cost of shipping their cargoes. The work is mainly concerned with the operational management problem of the fleet owned by a major oil company, a typical industrial carrier. The optimal fleet management problem for the major oil company can be divided into two phase problem. The front end corresponds to the production operation problem of the transportation of crude oil, the refinery operation, and the distribution of product oil to comply with the demand of the market. The back end is to tackle the fleet scheduling problem to meet the seaborne transportation demand derived from the front end. Relevant optimization models for each phase are proposed and described briefly. Then a user-friendly integrated fleet management support system is built based on the proposed optimization models for both ends under Windows environment. A case study reflecting the practices of fleet management problem for the major oil company is carried out by using the system.

• Proceedings of the Korean DIstribution Association Conference
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• 2003.02a
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• pp.109-120
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• 2003

As the logistics industrial environment becomes more complex and its scale becomes increase, the vehicle fleet scheduling system has become recognized the necessity as a major strategy in the logistics field. The vehicle fleet scheduling system is computerized package that find the vehicle routes and schedules to accomplish the required service to customers using vehicles. This paper introduces the state of the art of vehicle fleet scheduling system in Korea and foreign country and the future research subject are presented.

• Journal of Korea Port Economic Association
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• v.33 no.3
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• pp.105-120
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• 2017

This study analyzed changes in the competitive structure of the global shipping container market and the appropriate capacity of the container fleet in Korea from three perspectives. The competitive market analysis applied the market concentration ratio and Hirschman-Herfindahl index, while the appropriate capacity analysis was based on the following three aspects: (1) Fleet capacity to secure competitiveness in the global shipping alliance; (2) Fleet capacity to increase national fleet coverage of domestic import and export container cargo; and (3) Fleet capacity analysis through the panel model considering the characteristics of the major shipping countries. Analysis of the global shipping container market reveals an oligopoly industry, and Korea's container fleet capacity is insufficient across all three analyses.

• Journal of Navigation and Port Research
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• v.48 no.2
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• pp.104-108
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• 2024

This study investigates the relationship between national controlling fleets and the managerial performance of ship management companies in Korea. As industries clearly show interrelations between upstream and downstream entities , it is likely that the managerial performance of ship management companies in Korea is affected by the size of national fleet. Therefore, the present study analyzes the impact of Korean fleet size on the growth and the profitability of ship management firms. To this end, the performances of 10 major ship management companies in the period from 2012-2022 are examined through panel data regressions. The results indicate that the size of the national fleet has a positive impact on growth in both the assets and the sales of ship management companies. Specifically, the size of the Korean-flagged fleet is the most crucial factor, while that of the foreign-flagged fleet has no significant effect. In stark contrast to the findings regarding growth, the size of national fleet is found to have no significant impact on the profitability of ship management companies. This study's findings are expected to provide valuable implications informing both the managerial decision-making of ship management companies as well as policy-making for shipping and its related industries.

• Journal of National Security and Military Science
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• s.7
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• pp.155-231
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• 2009

Xu-Jing(徐競) an official of the Song(宋), a medieval Kingdom of China, wrote a book titled $\ll$Koryo Tu Jing(高麗圖經)$\gg$ which explains his travel to the Koryo as a member of diplomatic mission in 1123. $\ll$Koryo Tu Jing$\gg$ is the record of his personal experience in Koryo with many explanatory illustrations and especially contains 5 months' voyage record of his diplomatic fleet. His fleet set sail at a port located in the Ding Hai Xian(定海縣), Ming Zhou(明州) via a few islands of Koryo [Hyup Kye San(俠界山) , the Kun San Do(群山島) , the Ja Yon Do(紫燕島) , the Keup Su Mun(急水門) in Kang Hwa Gun(江華郡) and the Hap Gul(蛤窟) ] and finally arrived the Port Ye Song Hang(禮成港) . According to the Xu-Jing's record his fleet sailed the sea with the help of the favorable seaward winds and tides as the usual way of ancient sailing. The Xu- Jing's Fleet sailed the sea between the Mei Cen(梅岑), Ming Zhou(明州) of China and the Hyup Kye San(俠界山) of Koryo from about 5:00 a.m., May 24th(of the lunar calendar) to about 5:00 p.m., June 2nd. At this section, the average speed of the seaward winds was 19.45km/h and the average speed of the fleet which sailed only by the power of the winds was 6.29km/h. This means that 32.3% of the favorable seaward winds' speed was equal to the speed of the ancient fleet which sailed only by the power of the favorable seaward winds. The fleet sailed the sea between the Ja Yon Do(紫燕島) and the Keup Su Mun(急水門) from about 9:00 a.m., June 10th to about 1:00 p.m., the same day. At this section the fleet sailed by the power of tides in addition to the favorable seaward winds without oaring. The average speed of the winds was not different from that of former section and the average speed of the tides was 1.937km/h. And at this section the average speed of the fleet increased by 0.41km/h than that of the former section. This means that 21.1% of the speed of the tides was equal to the increased speed of the ancient fleet by virtue of the tides. The fleet sailed the sea between Keup Su Mun(急水門) and the Hap Gul(蛤窟) from about 1:00 p.m., June 10th to about 3:00 p.m., the same day. At this section, there were no seaward winds and the fleet sailed only by the powers of tides and oaring. And at this section, the tide increased the average speed of the fleet by 0.3114km/h and the fleet could sail at the speed of 4.3km/h. So we can conclude that the average speed of ancient fleet without any influences of the seaward winds and tides was 3.98 km/h. We can make use of the various sailing speeds of ancient fleets when judging their maritime activities. If we make use of the various sailing speeds of the ancient fleets as calculated in this article, we will be able to get various important informations about the certain ancient fleet's maritime maneuver. For example, we can infer the sailing routs of a certain fleet and the time when the fleet passed a certain spot by making use of the various sailing speeds of the ancient fleet. In this article I did not take account of the shapes of ships that consist of the ancient fleets and the sizes of the various ships and fleets. It was because that such factors would not change the foresaid conclusions seriously.

• Journal of the military operations research society of Korea
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• v.6 no.2
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• pp.47-67
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• 1980

Interactions of major activities participating in fleet operations are investigated in the framework of a closed queueing network system with finite aircrafts assigned to it. An implementable algorithm is developed, which is useful for computing the distributions needed to evaluate the effects of the interactions on the fleet operations. The availability management program is focused on seeking an optimal resource allocation to multiple repair-shops to maximize the fleet availability subject to the budget constraint.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.3
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• pp.256-263
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• 2002

This paper addresses a planning problem in a pickup-delivery transportation' system under dynamic vehicle dispatching. We present a procedure to determine a fleet size in which stochastic characteristics of vehicle travels are considered. Statistical approach and queueing theory are applied to estimate vehicle travel time and vehicle waiting time, based on which an appropriate fleet size is determined. Simulation experiments are performed to verify the proposed procedure.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.227-232
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• 2000

• Journal of Navigation and Port Research
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• v.27 no.3
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• pp.289-295
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• 2003

The international oil majors have been reducing the size of their own oil tanker fleet since early 1980s. Like international oil majors, the Korean refineries are becoming more dependent on tanker chartering rather than tanker ownership for their oil transportation since the 1990s. They also prefer spot charter to time charter and this kind of trend has continued up to now. Consequently, this paper attempted to find the factors influencing changes in tanker fleet composition. To attain the object of the paper, an empirical study is adopted using the ten decision-making factors derived from preceeding studies. The findings are that MARPOL and OPA 90, and transportation costs are the most important factors influencing an oil tanker fleet composition.