• IE interfaces
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• v.16 no.3
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• pp.332-343
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• 2003

This paper deals with pre-erection scheduling and erection scheduling in shipbuilding. Among shipbuilding scheduling, the ship erection scheduling in a dock is one of the most important since the dock is the most critical resource in a shipyard. However, it is more reasonable to consider pre-erection scheduling and erection scheduling as unified because they compete with the common constrained resources such as labor, crane, space, and so on. It is very hard to consider two scheduling problems simultaneously, and hence, we approach them sequentially. At first, we propose space resource leveling heuristics in pre-erection scheduling given erection date. And then, considering the manpower resource determined by pre-erection scheduling, we also propose manpower resource leveling heuristics in erection scheduling. Various experimental results with real world data show that the proposed heuristics have good performance in terms of scheduling quality and time.

• IE interfaces
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• v.12 no.4
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• pp.617-624
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• 1999

In order to maximize an availability of machine and utilization of space, the parallel machines scheduling problem with space limit is frequently discussed in the industrial field. In this paper, we consider a scheduling problem for assembly machine in ship engine assembly shop. This paper considers the parallel machine scheduling problem in which n jobs having different release times, due dates and space limits are to be scheduled on m parallel machines. The objective function is to minimize the sum of earliness and tardiness. To solve this problem, a heuristic is developed. The proposed heuristic is divided into three modules hierarchically: job selection, machine selection and job sequencing, solution improvement. To illustrate its effectiveness, a proposed heuristic is evaluated with a large number of randomly generated test problems based on the field situation. Through the computational experiment, we determine the job selection rule that is suitable to the problem situation considered in this paper and show the effectiveness of our heuristic.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.1
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• pp.89-100
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• 2016

Given the unpredictability of the space environment, satellite communications are manually performed by exchanging telecommands and telemetry. Ground support for orbiting satellites is given only during limited periods of ground antenna visibility, which can result in conflicts when multiple satellites are present. This problem can be regarded as a scheduling problem of allocating antenna support (task) to limited visibility (resource). To mitigate unforeseen errors and costs associated with manual scheduling and mission planning, we propose a novel method based on a genetic algorithm to solve the ground support problem of multiple satellites and antennae with visibility conflicts. Numerous scheduling parameters, including user priority, emergency, profit, contact interval, support time, remaining resource, are considered to provide maximum benefit to users and real applications. The modeling and formulae are developed in accordance with the characteristics of satellite communication. To validate the proposed algorithm, 20 satellites and 3 ground antennae in the Korean peninsula are assumed and modeled using the satellite tool kit (STK). The proposed algorithm is applied to two operation modes: (i) telemetry, tracking, and command and (ii) payload. The results of the present study show near-optimal scheduling in both operation modes and demonstrate the applicability of the proposed algorithm to actual mission control systems.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.283-285
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• 2001

The most work-space invest much time and labor for optimal arrangement. The work-plates of the work-space should be arranged, processed and assembled under the restricted work space. The optimal arrangement under the terms of a restriction arrange the maximum work-plates in appointed work-space. It's the central aim. The work-plates arrangement scheduling of the most work-space are achieved through the experience of the planner. Like this, if the work-plates arrangement is worked by hand, there spend much time for the training planner. And the burden of the personnel expenses occur for using the master worker, also there are dangerous factors to be able to bring the bottleneck circumstance for the process planning, because the quick work planning does not accomplish. With such problems, the biggest problem is inferior the value of the plan. For solved the such problem of hand-operating, some work-spaces developed and used the work-plate arrangement scheduling system for the special quality of themselves. This paper make research into a plan to develop the work-plate arrangement scheduling system efficiently.

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.23-32
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• 2011

Domestic leading construction companies has been establishing and performing TACT scheduling method, similar to linear scheduling model such as line of balance and repetitive schedule, and etc. in which repetitive construction works are involved like high-rise building. Linear scheduling model has been researched as a visual scheduling method presenting the work space and time information. Likewise scheduling constraints of CPM network such as finish-to-finish, start-to-start, finish-to-start, start-to-start, linear scheduling model also has the relationships constraints, namely boundary conditions, between activities. It is especially necessary to define the boundary conditions of the activities' relationships in order to apply the linear scheduling model to be compatible with the network schedule. Therefore, this research considers the boundary conditions between activities for establishing the linear scheduling model. This paper also applies the proposed boundary conditions to TACT schedule and then deduces the main considerations in order to establish and perform TACT schedule.

• Journal of Astronomy and Space Sciences
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• v.20 no.3
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• pp.227-238
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• 2003

Spacecraft mission planning functions including event prediction, mission scheduling, command planning, and ground track display have been developed for the KOMPSAT-2 mission operations. Integrated event prediction functions including satellite orbital events, user requested imaging events, and satellite operational events have been implemented. Mission scheduling functions have been realized to detect the mission conflicts considering the user specified constraints and resources, A conflict free mission scheduling result is mapped into the spacecraft command sequences in the command planning functions. The command sequences are directly linked to the spacecraft operations using eXtensible Markup Language(XML) for command transmission. Ground track display shows the satellite ground trace and mission activities on a digitized world map with zoom capability.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.643-648
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• 2005

The planning process for roadway construction involves a large amount of information on design, construction methods, quantities, unit costs, production rates, and site conditions. Therefore, it is very important to acquire, manage, and process the necessary information efficiently to produce a rigorous construction plan. GIS (Geographic Information System) is a very effective tool for integrating and managing various types of information including spatial and non-spatial data required for roadway construction planning. This paper proposes a GIS-based system for improving roadway construction planning with its 'Interactive Space Scheduling' and 'Operation Level Planning' functions. The proposed system can assist construction planners in a unique way by integrating design and construction information and creating modularized design elements for space scheduling in real time. It is expected that the proposed system could improve the efficiency of roadway construction planning.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.1
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• pp.48-57
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• 2010

A comparison of two kinds of scheduling optimization algorithms is presented in this paper. As satellite control and operation techniques have been developed, satellite missions became more complicated and overall quantity of missions also increased. These changes require more specific consideration and a huge amount of computation for the satellite mission scheduling. Therefore, it is a good strategy to make a scheduling optimization algorithm for the efficient satellite mission scheduling operation. In this paper, two kinds of scheduling optimization algorithms are designed with tabu-search algorithm and genetic algorithm respectively. These algorithms are applied for the same mission scenario and the results of each algorithm are compared and analyzed.

• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.103-113
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• 2012

A yard in a container terminal is a temporary storage space before containers are loaded onto the target vessel or delivered to consignees. For improving the utilization of the space in the yard and the efficiency of loading and discharging operations, it is important that operation plans must be carefully constructed in advance. A heuristic method is suggested to solve operation space planning problems considering workloads on handling equipment as well as space availabilities. The operation plans in this paper includes quay crane (QC) schedules and space plans for multiple vessels considering the workload in the container yard of container terminals. This paper evaluates the effectiveness of a space planning method and the performance of a new QC scheduling method using a simulation model.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.11
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• pp.973-980
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• 2016

An air traffic management (ATM) has been studied in a variety of fields to utilize an air traffic capacity efficiently and solve a congested air traffic situation due to an increment of an air traffic demand. In this paper, an air traffic management, which is related with controlling and determining the sequencing of an aircraft approaching to an airport, in terminal control area is studied. This paper focuses on scheduling algorithms with a given problem for the air traffic management with operational constraints, such as a space separation, an overtaking on the same air-route, and a route merge point (a scheduling point). For a real-time calculation, the presented algorithms focus on dispatching heuristic rules which are able to assign tasks in a fast time period with an adequate performance, which can be demonstrated as a proper and realistic scheduling algorithm. A simulation result is presented to illustrate the validity and applicability of the proposed algorithm. Each scheduling rule is analyzed on the same static and dynamic air traffic flow scenario with the ATM Monte-Carlo simulation.