• Journal of Institute of Control, Robotics and Systems
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• v.18 no.4
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• pp.302-307
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• 2012

Real-time systems perform periodic tasks and real-time aperiodic tasks such as alarm processing. Especially the periodic tasks included in control systems such as robots have precedence relationships among them. This paper proposes a new scheduling algorithm based on topological sort and residual time. The precedence relationships among periodic tasks are translated to the priorities of the tasks using topological sort algorithm. During the execution of the system the proposed scheduling algorithm decides on whether or not a newly arrived real-time aperiodic task is accepted based on residual time whenever the aperiodic task such as alarm is arrived. The proposed algorithm is validated using examples.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.3
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• pp.118-126
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• 2009

This research investigates the problem of minimizing setup costs in resequencing jobs having first-in, first-out(FIFO) constraints at conveyorized production or assembly systems. Sequence changing at conveyor junctions in these systems is limited due to FIFO restriction. We first define the general problem of resequencing jobs to workstations satisfying precedence relationships between jobs(Generalized Sequential Ordering Problem, GSOP). Then we limit our scope to FIFO precedence relationships which is the conveyor selection problem at a diverging junction(Diverging Sequential Ordering Problem, DSOP), modeling it as a 0-1 integer program. With the capacity constraint removed, we show that the problem can be modeled as an assignment problem. In addition, we proposed and evaluated the heuristic algorithm for the case where the capacity constraint cannot be removed. Finally, we discuss the case study which motivated this research and numerical results.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.3 s.18
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• pp.77-83
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• 2004

This paper focuses on a scheduling problem of military training. Repetitive and identical training over multiple serials is a common type of military education. A simple but systematic method is suggested to determine a training schedule for small groups divided from each serial. A satisfactory training schedule and the number of such small groups can be determined by iteratively solving assignment problems with additional constraints. With this method, loads of instructors can also be balanced without violating constraints associated with precedence and continuity relationships among lectures.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.5
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• pp.748-758
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• 2010

Navy surface vessels require pier services such as emergency repair, oil supply, arm loading/unloading, craning, standby readiness, normal repair, gun arrangement, ammunition loading, and food loading during the period in port. The purpose of this study is to establish efficient berth allocation plan for navy surface vessels in home port under the limited resources of piers and equipments. This study suggests Mixed Integer Programming model for berth allocation problem, considering precedence relationships among services and the uncertainty of the arrival and departure for each vessel. For an effective analysis, the model is implemented by ILOG OPL(Optimization Programming Language) Studio 6.0 and ILOG CPLEX 11.1., which shows a reasonable result.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.1
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• pp.1-17
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• 1993

It is well known that an assembly operation is usually constrained by the geometric interference between parts. These constraints are normally presented as AND/OR precedence relationships. To find a feasible assembly sequence which satisfies the geometric constraints is not an easy task because of the TSP(Traveling Salesman Problem) nature with precedence constraints. In this paper, we developed an automated system based on Neural Network for generating feasible assembly sequences. Modified Hopfield and Tank network is used to solve the problem of AND/OR precedence-constrained assembly sequences. An economic assembly sequence can be also obtained by applying the cost matrix that contains cost-reducing factors. To evaluate the performance and effectiveness of the developed system, a case of automobile generator is tested. The results show that the developed system can provide a "good" planning tool for an assembly planner within a reasonable computation time period.

• Journal of Navigation and Port Research
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• v.28 no.1
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• pp.83-90
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• 2004

Navy surface vessels require pier services such as emergency repair, oil supply, arm loading / unloading, craning, standby readiness, normal repair, gun arrangement, ammunition loading, and food loading during the period in port. The purpose of this study is to establish efficient berth allocation plan for navy surface vessels in home port under the limited resources of piers and equipments. This study suggests Mixed Integer Programming model for berth allocation problem, considering precedence relationships among services. For an effective analysis, the model is implemented by ILOG OPL(Optimization Programming Language) Studio 3.1 and ILOG CPLEX 7.0. The results of the model show reduction of berth shifts and increasement of service benefits.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.391-396
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• 2013

As the construction environment has been changing all the times, the techniques for managing the construction projects have been improved accordingly. The schedule management technique, one of the construction management tools, has been evolved as well in order to be adaptable to new construction environment. Most of newly proposed scheduling techniques have been based on the Critical Path Method (CPM) that was proposed in 1956. The CPM is classified into two categories, Arrow Diagramming Method (ADM) and Precedence Diagramming Method (PDM). ADM is so good in the visual format but it cannot express the overlapping relationships between two consecutive activities. On the other hand, PDM can express the overlapping relationships but it is unsatisfactory in the visual format. Recently, as the construction environment becomes more complex and the role of schedule management becomes more and more important, the overlapping expression becomes one of critical factors for scheduling as well. Most of construction project participants prefer more comfortable visual format, however, the scheduling software based on the PDM cannot satisfy their basic requirement. Beeliner, new scheduling software based on the Beeline Diagramming Method (BDM) that was proposed in 2010, was developed in 2012, it can express more flexible overlapping relationships and has superior visual format as well. This paper presents major features and applications of Beeliner, and makes construction professionals understand new scheduling concept and its applications.

• Korean Journal of Construction Engineering and Management
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• v.13 no.5
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• pp.144-152
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• 2012

The reason why most scheduling softwares currently using at construction projects adopt PDM (Precedence Diagramming Method) is that it can express an overlapping relationship between activities. However, the overlapping relationships in PDM are represented only by combinations of four overlapping types that connect the start and finish points of two activities, therefore, PDM cannot express efficiently the relationships between any middle points of two activities if they should be represented. This research proposes the method of transforming the four overlapping types of PDM to the overlapping relationships of BDM(Beeline Diagramming Method), new networking technique, that can connect the inter-relationships at any middle points of two activities as well as express multiple overlapping relationships. The proposed method will help not only to improve an efficiency of scheduling but also to upgrade the scheduling technique because BDM technique has a lot of unique advantages in scheduling.

• The Journal of Information Systems
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• v.21 no.2
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• pp.73-96
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• 2012

With emergence of smart technologies(e.g., smartphones), Location-Based Services(LBS) are expected to provide more enhanced values utilizing consumers' personal information than other smart services. However, in contrast to existing smartphone applications, LBS could raised severe consumer's privacy concerns because of rapidly changing information sensitive to consumers. In this context, the purpose of this study is to explore relationships among privacy concerns reduction, trust and intention to use LBS by examining the effect of precedence factors(social presence, reputation, mobile literacy, ability of information control) of privacy concern reduction. In addition, the study investigates the role of personal innovation as a moderating effect between privacy concern reduction and intention to use LBS. The results showed that the proposed precedence factors of privacy concerns with a exception of Mobile Literacy had a positive impact on privacy concerns reduction that then positively affected trust and intention to use LBS. In addition, the relationship between trust and intention to use LBS was significantly supported. Finally, personal innovation as a moderating effect significantly influenced the relationship between privacy concern reduction and intention to use LBS. This study is expected to be a reference for a subsequent study about the spread of LBS application of smartphone. Also, the finding of this study is meaningful for helping service direction to firms providing LBS.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.350-353
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• 2003

Navy surface vessels require pier services such as emergency repair, oil supply, fm loading/unloading, crane, standby readiness, normal repair, gun arrangement, ammunition loading, and food loading during the period in port. The purpose of this study is to establish efficient berth allocation plan for navy surface vessels in home port under the limited resources of piers and equipments. The study suggests Mixed Integer Programing (MIP) model for bath allocation problem, considering precedence relationships among services. For a effective analysis, the model is implemented by ILOG OPL(Optimization Programming Language) Studio 3.1 and ILOG Cplex 7.0. The results of the model show reduction of berth shifts and increasement of service benefits. And thus, it would be a possibility of contribution in the improvement of fleet readiness.