• International conference on construction engineering and project management
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• 2022.06a
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• pp.640-648
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• 2022

In the United States, the Safety Rest Areas (SRAs) were introduced as highway roadside infrastructures in the early 1900s. The State Departments of Transportation (DOTs) operate/maintain their SRAs using different methods. The Washington DOT used the in-house workforce method for over 20 years, whereas some states moved to Performance-Based Contracting (PBC) from the in-house workforce to save cost primarily. Several existing studies claimed that using the PBC approach saved costs on several highway assets. Thus, the principal objective of this study is to compute and compare the unit operating/maintenance cost of SRAs using the in-house workforce method (in Washington state) with the PBC approach (in other states). The findings of this study show that the average annual cost using the PBC approach was much more than the average annual cost using the in-house workforce approach. The findings also show that in Washington state, the 'Labor Cost' category was a key expenditure, which is statistically higher than other categories. The 'Labor Cost' was followed by the 'Other Services', and then 'Materials and Supplies' and 'Equipment.' The study's findings indicated that outsourcing does not always save costs for agencies. The study findings may help transportation construction/maintenance professionals select a cost-effective approach for their future planning.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.656-659
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• 2004

The objective of this paper is to analyze the combined productivity at automated container terminal. We present a simulation model for transport vehicle that perform the container transportation between apron and yard with a perpendicular yard layout. Usually, the efficiency of container terminal is evaluated by productivity of container cranes at apron, and though there are enough support of transport vehicles and yard cranes, can improve the productivity of container cranes. Especially, transport vehicle is very important factor in productivity of container cranes and has variable work productivity according to loading and unloading situation. Therefore, a method that can estimate combined productivity of equipment is required. We performed various simulation experiment and analyzed combined productivity to estimate the required number of equipment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.10a
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• pp.117-124
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• 1998

This paper proposes a simulation model which evaluates operation plans of container terminal. The operation plans of container terminal consist of berth plan, load plan, unload plan, yard plan, and equipment plan. It is discussed how to apply the simulation method to evaluate those plans. Simulation analysis is based on data about plans from the operation planning system through an interface program. It is discussed what we should got in the simulation, for example, the statistics about container-handling equipment such as container cranes, transfer cranes, yard tractors, and trailers used in the transportation of containers.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1335-1344
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• 2010

Urban railroad is the central axis of public transportation which transport the citizens quickly and safely. The idea of the maintenance of urban railroad cars is preventive maintenance aiming at breakdown prevention, and it should be performed conforming to the fixed regulations and maintenance guide. The accuracy of maintenance and the punctuality of rolling stock operation could be secured by reliable inspection equipments. In this study, a scientific maintenance and safe operation of rolling stocks & a method of improving work efficiency will be examined through the case that Busan Urban Railroad has developed its own vehicle inspection equipment and has been making good use of it.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.2
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• pp.11-19
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• 2012

Crane systems have been widely used for transportation in building sites, ports, nuclear wastehandling operation and so on. As a typical underactuated system, an overhead crane has such merits as high flexibility and less energy consumption. And it's getting more types of cranes, universally applicable algorithms should be developed. That is the design and development of scalable algorithms are required. Developed algorithms can be used for the controller and crane overload protection that meets the requirements of the algorithm are presented. These algorithms force the state to warn the operator and stops the operation of equipment. In this paper, crane overload conditions that can cause damage to alert the operator, and to limit the operation of equipment overload protection algorithm is presented.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.433-444
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• 2008

Nowadays, subway station has provided not only transportation but living spaces for everyday activities. Therefore, a variety of facilities have been installed for a safety of citizens such as fire-fighting equipment, platform screen doors and giving high level of benefits such as air-conditioning and heating equipment, escalators, lighting apparatus. In order to operate these facilities appropriately, it is needless to say that electric power supply must be reliable. Many protection relays have been installed to protect electric apparatus and power system, nevertheless it..s study has been insufficient in the concrete. From this paper, through analyzing of protection relay system of electric room operated in line 2 of Seoul metro, we can help to improve stable power supply system of subway station.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.885-889
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• 2006

Metro Subway System is widely known as the leader of public transportation in a metropolitan area. The signal interlocking is one of the most important organs that plays a major role in the system. By improving the quality of signal lights on the traffic system and keeping its maintenance on a high level will not only repair the current state, but it will also let the LED type signal semi-permanent. The device, which underwent a process of fine manufacture establishment and a close examination, obtained a patented article (2004, as a new device). Utilizing the equipment with cautious preservation on the system will enhance the current state of the signal device. Especially, the test for improvement and development based upon the technique that decreases the frequency of defect produced will further precipitate its efficiency. With authorization of imposing the LED lights on production, installment, and investigation of the system, the newly made equipment will bring improvement to the signal technology and to the industry at largest extent.

• Industrial Engineering and Management Systems
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• v.11 no.4
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• pp.299-309
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• 2012

This paper introduces some of the developments related to the handling equipment in container terminals and various new conceptual handling systems that have been proposed during the last several decades. The basic ideas behind the previous equipment improvements are analyzed to identify future directions that can be used for devising new handling systems. The handling systems in the container terminals include a quayside handling system, transport system, and yard system. In response to the deployment of mega-sized vessels for container transportation systems, productivity improvement has become one of the most urgent issues in the container terminals. This paper analyzes the previous improvements made for achieving higher productivity in the three subsystems of container handling. Some conceptual handling systems are introduced including the linear motor conveyance system (LMCS), automated storage and retrieval systems (AR/RS), overhead grid rail (GRAIL), SPEEDPORT, SuperDock, the automated container system by ZPMC (ACS-ZPMC), and AUTOCON.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.183-183
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• 2007

Bimodal Tram is a new public transportation system combined subway with bus and consists of variable electric equipment to accomplish the comfortness, reliability, safety and so on. One of them is VCU(Vehicle Control Unit) for Performing driver's cmmand and monitoring the state of other equipment. To lessen the wiring and the interference of outer electromagnetic noises is very important things for bimodal tram with complicated configuration of electric equipments. This paper has investigated the application of CAN(Controller Area Network) communication method for VCU which has display, central unit and several nodes that are connected with other electric equipments(HVAC, door controller etc). We designed and manufactured the prototype of VCU which eventually will be installed on bimodal tram being developed in KRRI at present.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.112-118
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• 2013

This paper reports the results of a comparative study on rudder performance between the steel rudders that have been used in coastal angling fishing boats in the 20-GT class and the newly developed FRP composite material rudders. In order to compare the rudder performances of these two types, a sea trial test was carried out to investigate the speed performance, fuel consumption, and ship's turning ability. The results showed that the sea trial performance of the FRP composite rudder was better than that of the steel rudder type in terms of the sea speed, fuel consumption rate, and turning ability.