• 한국항공운항학회지
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• 제26권2호
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• pp.54-60
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• 2018

This paper contains the multi-mission scheduling optimization of UAV within a given operating time. Mission scheduling optimization problem is one of combinatorial optimization, and it has been shown to be NP-hard(non-deterministic polynomial-time hardness). In this problem, as the size of the problem increases, the computation time increases dramatically. So, we applied the genetic algorithm to this problem. For the application, we set the mission scenario, objective function, and constraints, and then, performed simulation with MATLAB. After 1000 case simulation, we evaluate the optimality and computing time in comparison with global optimum from MILP(Mixed Integer Linear Programming).

• 전기학회논문지
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• 제56권10호
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• pp.1721-1730
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• 2007

SThis paper proposes a new dispatch scheduling algorithm in interconnected regional system operations. The dispatch scheduling formulated as mixed integer non-linear programming (MINLP) problem can efficiently be computed by generalized Benders decomposition (GBD) algorithm. GBD guarantees adequate computation speed and solution convergency since it decomposes a primal problem into a master problem and subproblems for simplicity. In addition, the inter-temporal optimal power flow (OPF) subproblem of the dispatch scheduling problem is comprised of various variables and constraints considering time-continuity and it makes the inter-temporal OPF complex due to increased dimensions of the optimization problem. In this paper, regional decomposition technique based on auxiliary problem principle (APP) algorithm is introduced to obtain efficient inter-temporal OPF solution through the parallel implementation. In addition, it can find the most economic dispatch schedule incorporating power transaction without private information open. Therefore, it can be expanded as an efficient dispatch scheduling model for interconnected system operation.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2005년도 하계학술대회
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• pp.382-387
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• 2005

There are many studies on arbitrarily divisible load scheduling problem in a distributed computing network consisting of processors interconnected through communication links. It is not efficient to arbitrarily distribute the load that comes into the system. In this paper, how to schedule in case that arbitrarily indivisible load comes into the system is studied. Also, the cases of the divisible load mixed with the indivisible load that come into network were dealt with optimal load distribution in parallel processing system by scheduling applied to linear programming.

• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1063-1069
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• 2016

• 설비공학논문집
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• 제29권12호
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• pp.638-644
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• 2017

Optimal cooling operation algorithm was developed based on a simulation case of a single family house model equipped with renewable energy facility. EnergyPlus simulation results were used as virtual test data. The model contained three energy storage elements: thermal heat capacity of the living room, chilled water storage tank, and battery. Their charging and discharging schedules were optimized so that daily electricity bill became minimal. As an optimization tool, linear programming was considered because it was possible to obtain results in real time. For its adoption, EnergyPlus-based house model had to be linearly approximated. Results of this study revealed that dynamic cooling load of the living room could be approximated by a linear RC model. Scheduling based on the linear programming was then compared to that by a nonlinear optimization algorithm which was made using GenOpt developed by a national lab in USA. They showed quite similar performances. Therefore, linear programming can be a practical solution to optimal operation scheduling if linear dynamic models are tuned to simulate their real equivalents with reasonable accuracy.

• 제어로봇시스템학회논문지
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• 제14권5호
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• pp.462-466
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• 2008

This paper proposes a stable gain scheduling method of linear time invariant controllers for tracking servo system. In order to read and write the data on the optical disc, the pick-up head should be moved to the exact track quickly and follow the track immediately. Two different controllers are used for each moving and track-following. In pull-in period, a transition period from moving to track-following, the head might slip and miss the target track. This brings on another searching process and increases the total time. One way to avoid slipping is to extend the bandwidth of the track-following controller. But, extending the bandwidth could degrade the following performance. More prevalent way is to use one more controller in this pull-in period and switch to the following controller. In general, however, switching or scheduling of stable controllers cannot guarantee the stability. This paper suggests an scheduling method guaranteeing the overall stability not only in a generalized form but also in special form for SISO system. The sufficient condition is derived from the fact that Q factor of a stable controller should be stay in $RH_{\infty}$ space. In the experiment, the proposed method shows better performance than the switching method such as shorter time and lower current consumption.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.945-949
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• 2004

These days there are so many scheduling systems or softwares. But only few scheduling systems have succeeded in the market. In spite of powerful engine and functions, those systems have difficulties to be applied in real processes. In real processes, there are various constraints caused by physical or systematical environments of plants. Those constraints are too many to be handled in the system. This problem makes it difficult for the system to represent the details of processes. In order to resolve this problem, we have developed a specialized scheduling system for a target process. The system could be developed by the experts for target process and researchers for scheduling. In this study, a scheduling system for PVC process has been developed as an MILP (Mixed integer linear programming) model and coded in $Fortran^{TM}$. The scheduling system has been applied to two processes, which have different characteristics. Simulation results indicate that the profit of the target process can be increased by about 5% by implementing the scheduling system.

• 한국건축시공학회지
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• 제13권6호
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• pp.565-578
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• 2013

Batch production is common in repetitive construction projects, and it is not unusual for different batch sizes to be used by contractors in one project. While several scheduling methods, such as the Linear Scheduling Method (LSM) and the Repetitive Scheduling Method (RSM) have been proposed and used, no mathematical method for repetitive construction projects has been developed, and it is difficult to consider different batch sizes with the existing methods. An original mathematical algorithm for scheduling repetitive projects with different batch sizes is proposed in this study. This algorithm is illustrated with assumptions of resource continuity and single path in a project and introduces new terms, control batch and critical batch. The algorithm logics and mathematical equations are validated by comparison with the outcomes from a graphical scheduling approach through a simple and practical hypothetic project. As a result, it is expected that the proposed algorithm can be easily adapted and extended to computer software for scheduling, and can be a starting point for research on batch size management in repetitive construction projects.

• 한국정보처리학회논문지
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• 제6권8호
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• pp.2196-2203
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• 1999

본 논문은 데이터패스 합성에서의 버스 스케줄링 문제와 레지스터의 최적화 방법을 다룬 것이다. 스케줄링은 DFG(Data Flow Graph)의 연산을 제어스텝(control step)에 할당하는 과정으로서, 주어진 조건을 만족하는 범위 내에서 비용함수(cost function)의 최소화에 목적을 둔다. 이를 위해 본 논문에서는, 연산자 배치를 위한 하드웨어 할당(hardware allocation) 과정에서의 설계비용을 최소화시키기 위해, 연산결과를 저장하는 레지스터(register)와 연산간의 이동 통로인 버스(bus)의 최적화 기법을 논하였다. 특히, 하드웨어 할당과정의 중요한 과제인 버스와 레지스터의 최소화 기법을 논하였으며, 레지스터의 최적화는 스케줄링이 완료된 후의 결과를 이용하였다. 실험대상으로는 벤치마크 모델인 5차 디지털 웨이브필터(5th-order digital wave filter)를 사용하였으며, 본 논문의 결과를 기존결과와 비교함으로써, 본 논문의 효용성을 입증하였다. 모든 실험결과는 구조형태의 선형정수계획법(ILP : Integer Linear Programming)을 이용함으로써, 모든 경우에 언제나 최적의 결과를 얻을 수 있도록 하였다.

• 한국산학기술학회논문지
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• 제12권4호
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• pp.1565-1574
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• 2011

다이캐스팅 스케줄링은 각 쉬프트마다 생산되는 주조제품의 개수를 결정하여 주어진 성능지수를 최적화하는 작업이다. 본 논문은 다이캐스팅 스케줄을 실제 주조공정에 적용할 때 불량주물 등의 이유로 발생하는 결품을 방지하는 새로운 기법을 제안한다. 선형계획법으로 모델링된 기존의 다이캐스팅 스케줄링은 용탕에 대한 용융로의 평균효율을 최대로 하지만 주조공정에서 불량품이 발생하는 문제에는 대처하지 못한다. 제안된 기법에서는 이전 쉬프트에서 불량주물이 발생하는 경우, 이를 대체할 수 있도록 현재 쉬프트에서 주조공정이 끝나고 남은 용탕의 잔여량을 이용하여 추가로 생산한다. 이 방법은 이미 최적화된 투입 용탕의 양이나 스케줄링 결과를 변경하지 않고도 불량이 발생한 주조제품의 생산량을 최대한 보상할 수 있는 장점을 지닌다. 사례 연구를 통하여 새로 제안된 기법의 우수성과 응용 가능성을 검증한다.