• Korean Journal of Construction Engineering and Management
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• v.20 no.5
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• pp.42-51
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• 2019

The train operation institution establishes a transportation plan based on the forecast of transport demand and the ability of train vehicles to transport, and establishes a train operation plan accordingly. The train operation plan adjusts the intervals between trains, creates a timetable (train diagram) for trains, and establishes a plan for the operation of train vehicles used for train operation. The train operation institution shall establish a crew schedule to determine and place the crew members of the trains arranged in the diagram in order to enhance the efficiency of the operation management of the trains. In this study, the authors apply the neighborhood search method that satisfies the constraints at the phase of generating the crew diagram. This suggests a methodology for efficient management of crew schedule plan. The crew diagram generated in this study compared with the existing crew diagram in accordance with the actual operating train timetable, and verified the effectiveness of the suggested method.

• Korean Journal of Computational Design and Engineering
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• v.6 no.1
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• pp.24-30
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• 2001

An efficient and robust algorithm to compute the exact Voronoi diagram of a circle set is presented. The circles are located in a two dimensional Euclidean space, the radii of the circles are non-negative and not necessarily equal, and the circles are allowed to intersect each other. The idea of the algorithm is to use the topology of the point set Voronoi diagram as a seed so that the correct topology of the circle set Voronoi diagram can be obtained through a number of edge flipping operations. Then, the geometries of the Voronoi edges of the circle set Voronoi diagram are computed. In particular, this paper discusses the topological aspect of the algorithm, and the following paper discusses the geometrical aspect. The main advantages of the proposed algorithm are in its robustness, speed, and the simplicity in its concept as well as implementation. Since the algorithm is based on the result of the point set Voronoi diagram and the flipping operation is the only topological operation, the algorithm is always as stable as the Voronoi diagram construction algorithm of a point set.

• Journal of the Korean Institute of Gas
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• v.16 no.6
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• pp.41-47
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• 2012

There are PFD(Process Flow Diagram) and P&ID(Piping and Instrument Diagram) for designing and managing chemical process efficiently. They provide the operation condition and equipment specifications of chemical process, but they do not provide the reliability of chemical process. Therefore, in this study, Reliability Flow Diagram(RFD) which provide the cycle and time of preventive maintenance has been developed using Directed Graph Analysis methodology. Directed Graph Analysis methodology is capable of assessing the reliability of chemical process. It models chemical process into Directed Graph with nodes and arcs and assesses the reliability of normal operation of chemical process by assessing Directed Graph sequential. In this paper, the chemical process reliability transition according to operation time was assessed. And then, Reliability Flow Diagram has been developed by inserting the result into P&ID. Like PFD and P&ID, Reliability Flow Diagram provide valuable and useful information for the design and management of chemical process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.651-654
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• 2010

This paper presents the establishment of the information of metadata for an Authorization tool of UML class diagram. When it comes to modeling classes in UML class diagram, the paper defines expressed classes and the relationship. The class represents the concept of an object, which defines Name, Attribute and Operation. The relationship is between classes, which defines the name and the type of the Relationship, From Class and To Class. And it suggests how to handle and process the information of metadata for an authorization tool of UML class diagram.

• The KIPS Transactions:PartD
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• v.16D no.4
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• pp.527-540
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• 2009

State diagrams describe the dynamic behavior of an individual object as a number of states and transitions between these states. In this paper, we propose an automated technique to the generation of a state diagram from class operations with pre/post conditions. And I also develop a supporting tool, SDAG (State Diagram Automatic Generation tool). Additionally, we propose a complexity metric and a state diagram generation approach concerning types of each operation for decreasing complexity of generated state diagram.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.699-702
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• 1999

This paper represents the application of a virtual plant simulator and a Ladder Diagram of PLC. A target plant is a material transport car that repeatedly conveys along the rails. The whole process is automatically operated by PLC. The simulation system consists of the POSFA PLC and the virtual plant simulator. We demonstrate that operation of a LD program corresponds to operation of the virtual plant simulator.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.106-110
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• 2002

The KTX, first Korean Highspeed train from Seoul to Busan, is scheduled to begin its passenger service in 2004, with improvement of existing railroad between Daegu and Busan and Honam region. This paper aims to suggest the best train operation plan and detailed diagram pattern so that the KTX could work effectively as much as possible. I suggest for instance, connecting direct train and local train, hub stations plan, multi-destination train, and improvement of fare system.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.211-213
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• 1998

This paper introduces the additional remote monitoring and remote setting functions needed to operate the distribution automation system effectively. we compare the additional functions with the old functions. The remote setting of minimum trip value of fault indicator is an example of additional function. It saves time and line-man's power. Also this paper describes the data transmission flow diagram for operation of distribution automation system using wireless communication method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.854-859
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• 2010

Distribution Automation System(DAS) is designed to improve operational efficiency by acquisition and control of remote data using its components such as central computation units, communication network and feeder remote terminal units. A conventional human machine interface of the DAS adopts a schematic diagram which is made by drawing power equipments on the geographic information system map. The single line diagram is more useful than the schematic diagram for the main tasks of distribution system operation such as protective relay coordination, service restoration and loss minimization. Since the configuration of the distribution line is changed according to the relocation of the open tie switches, the auto-drawing algorithm based on the connection between the sections and the switches is an essential technique. This paper proposes a new auto-drawing algorithm for a single line diagram of distribution systems based on tertiary tree and collision avoidance method. The feasibility of the proposed algorithm has been testified for various cases using practical distribution system with 12 feeders.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.10 s.352
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• pp.10-21
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• 2006

We have studied the characteristics of oxide VCSELS when their off-current and on-current are kept small in order to find out the possibility of low current operation. A large signal equivalent circuit model has been used. By comparing measured data and simulation results, the parameters of the large signal models are obtained including the capacitances. Using the large signal model, we have investigated the effects of capacitance and on/off currents upon the turn-on/turn-off characteristics and eye diagram. According to the experiment and simulation, the depletion capacitance, which has been neglected, is found to have significant influence on the him-on delay and eye-diagram. Therefore, for high speed and low current operation, the reduction of the depletion capacitance is essential.