• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.46
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• pp.241-251
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• 1998

There are two methods of load balancing for detail scheduling : One method is to generate an initial schedule and obtain an improved final schedule by load balancing only during a specific period. The other method is to generate an initial schedule and obtain an improved schedule by load balancing from current date(TIMENOW) to unlimited time with the whole manufacturing processes. This paper proposes an algorithm for detail scheduling which can be a practical solution in job shop production or project job type by applying the former method.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.2
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• pp.7-12
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• 2006

This study considers the problem of scheduling jobs on uniform parallel machines with a common due date. The objective is to minimize the total absolute deviation of job completion times about the common due date. This problem is motivated by the fact that a certain phase of printed circuit board manufacturing is bottleneck and the processing speeds of parallel machines in this phase are uniformly different for all jobs. Optimal properties are proved and a simple polynomial time optimal algorithm is developed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.23
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• pp.65-70
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• 1991

This paper is concerned with a flow-shop scheduling problem for all jobs having the common due date using V-Shape penalty cost function for earliness and lateness. The objective of the paper is to develop an efficient heuristic scheduling algorithm for minimizing total penalty cost function and for determining the optimal common due date. In addition, the between-job-delay for two machines are considered for developing the algorithm. A numerical example is given for illustrating the proposed algorithm.

• IE interfaces
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• v.9 no.2
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• pp.75-82
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• 1996

A scheduling system is developed for a parallel machine flow shop which reflects the situations of the manufacturing processes in the tire industry. The schedule is generated via simulation using heuristic rules to get satisfaction on such constraints as due dates, demands, work-in-process, process capacity, set-up times and scheduling speed. This system, constructed with relational DB, SQL and C language, consumes less than 10 minutes of PC simulation to handle real size problems.

• Journal of the Korea Society for Simulation
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• v.5 no.2
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• pp.1-12
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• 1996

Utilizing the simulation approaches, the dynamic production scheduling system FOLS(Flexible flowshop On-Line Simulation) is developed under the flexible flowshop environment. When an interruption such as machine failure/recovery is occurred at the shop floor, the FOLS system performs evaluations for job selection rule oriented alternatives, and generates a dynamic production schedule based on the collected current shop floor data. For the case study, the FOLS system is applied to the printed circuit card assembly(PCCA) line and simulation results are reported.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.8
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• pp.1303-1310
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• 1990

This paper describes the design and implementation of a system for automatic data path synthesis in digital system. There are four subtasks to synthesize a digital system: scheduling, register allocation, functional unit allocation and bus allocation. In this paper, force directed algorithm is used for the scheduling while new algorithms are proposed for the allocation subtasks. Synthesis results of two experimental data paths including MC6502 have shown that our proposed algorithm out goes most of previous works.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.5
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• pp.363-372
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• 2002

In ship operation, the roll motions can seriously degrade the performance of mechanical and personnel effectiveness. So many studies for the roll stabilization system design have been performed and good results have been achieved. In many studies, the stabilizing fins are used. Recently rudders, which have been extensively modified, have been used exclusively to stabilize the roll. But, in the roll stabilization control system, the control performance is very sensitive to the ship speed. So, we can see that it is important to consider the ship speed in the rudder roll control system design. The gain-scheduling control technique is very useful in the control problem incorporating time varying parameters which can be measured in real time. Based on this fact, in this paper we examine the;$H_{\infty}$-Gain Scheduling control design technique. Therefore, we assume that a parameter, the ship speed which can be estimated in real time, is varying and apply the gain-scheduling control technique to design the course keeping and anti-rolling control system far a ship. In this control system, the controller dynamics is adjusted in real-time according to time-varying plant parameters. The simulation result shows that the proposed control strategy is shown to be useful for cases when the ship speed is varying and robust to disturbances like wind and wave.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.339-348
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• 2011

Reconfigurable manufacturing system (RMS), alternatively called changeable manufacturing, is a new manufacturing paradigm designed for rapid change in hardware and software components in order to quickly adjust production capacity and functionality in response to sudden changes in market or in regulatory requirements. Although there has been much progress in hardware components during the last decade, not much work has been done on operational issues of RMS. As one of starting studies on the operational issues, we suggest a framework for the system setup and scheduling problems to cope with the reconfigurability of RMS. System setup, which includes batching, part grouping, and loading, are concerned with the pre-arrangement of parts and tools before the system begins to process, and scheduling is the problem of allocating manufacturing resources over time to perform the operations specified by system setup. The framework consists of 8 scenarios classified by three major factors: order arrival process, part selection process, and tool magazine capacity. Each of the scenarios is explained with its subproblems and their interrelationships.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.367-374
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• 2018

A trajectory-based scheduling system is proposed for air traffic management using next generation aviation data communication link. Based on the service concept of 4-dimensional trajectory data link (4DTRAD) using air traffic serveices (ATS) datalink Baseline 2, a procedure for trajectory-based operation of an en-route flight is established and described in detail. To mitigate air traffic controllers' workload which might be caused by various and complicated data utilization, a prototype of the scheduling system, which predicts the aircraft trajectory based on the flight intents received by air traffic service system and provides advisory information for air traffic control, was developed. The simulation environment for trajectory based operation was built to validate the scheduling functionality of the prototype.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3C
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• pp.219-233
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• 2008

Optimal scheduling of parallel tasks with some precedence relationship, onto a parallel machine is known to be NP-complete. The complexity of the problem increases when task scheduling is to be done in a heterogeneous environment, where the processors in the network may not be identical and take different amounts of time to execute the same task. This paper introduces a Duplication based Task Scheduling with Communication Cost in Heterogeneous Systems (DTSC), which provides optimal results for applications represented by Directed Acyclic Graphs (DAGs), provided a simple set of conditions on task computation and network communication time could be satisfied. Results from an extensive simulation show significant performance improvement from the proposed techniques over the Task duplication-based scheduling Algorithm for Network of Heterogeneous systems(TANH) and General Dynamic Level(GDL) scheduling algorithm.