아웃소싱을 고려한 병렬기계 일정계획 연구

이익선(Ik Sun Lee),윤상흠(Sang Hum Yoon) 한국산업경영시스템학회 2008 한국산업경영시스템학회지 Vol.31 No.3

  This paper considers an integrated decision for scheduling and outsourcing(or, subcontracting) of a finite number of jobs(or, orders) in a time-sensitive make-to-order manufacturing environment. The jobs can be either processed in a parallel in-house facilities or outsourced to subcontractors. We should determine which jobs should be processed in-house and which jobs should be outsourced. And, we should determine the schedule for the jobs to be processed in-house. If a job is determined to be processed in-house, then the scheduling cost(the completion time of the job) is imposed. Otherwise(if the job should be outsourced), then an additional outsourcing cost is imposed. The objective is to minimize the linear combination of scheduling and outsourcing costs under a budget constraint for the total available outsourcing cost. In the problem analysis, we first characterize some solution properties and then derive dynamic programming and branch-andbound algorithms. An efficient heuristic is also developed. The performances of the proposed algorithms are evaluated through various numerical experiments.

딥러닝 기법을 활용한 중국 주식시장 예측 연구

이익선(Ik Sun Lee) 한국경영과학회 2021 經營 科學 Vol.38 No.2

가중납기지연시간을 고려한 최적 주문처리순서에 관한 연구

이익선(Ik Sun Lee),윤상흠(Sang Hum Yoon) 한국경영과학회 2008 한국경영과학회지 Vol.33 No.2

This paper considers an order scheduling model to minimize the total weighted tardiness of orders. Each order requires different types of products. Each type of product is manufactured on its dedicated machine specified in advance. The completion time of each order is represented by the time when all the products belonging to the order are completed. The objective of this paper is to find the optimal production schedule minimizing the total weighted tardiness of a finite number of orders. In the problem analysis, we first derive a powerful solution property to determine the sequence of two consecutive orders. Moreover, two lower bounds of objective are derived and tested along with the derived property within a branch-and-bound scheme. Two efficient heuristic algorithms are also developed. The overall performances of the proposed property, branch-and-bound and heuristic algorithms are evaluated through various numerical experiments.

부품 생산과 조립으로 구성된 2단계 조립 일정계획의 Flowtime 최소화 연구

이익선(Ik Sun Lee),윤상흠(Sang Hum Yoon),하귀룡(Gui Ryong Ha),전재호(Jaeho Juhn) 한국산업경영시스템학회 2010 한국산업경영시스템학회지 Vol.33 No.4

This paper considers a 2-stage assembly flowshop scheduling problem where each job is completed by assembling multiple components. The problem has the objective measure of minimizing total completion time. The problem is shown to be NP-complete in the strong sense. Thus, we derive some solution properties and propose three heuristic algorithms. Also, a mixed-integer programming model is developed and used to generate a lower bound for evaluating the performance of proposed heuristics. Numerical experiments demonstrate that the proposed heuristics are superior over those of previous research.

두 단계 흐름생산라인에서 가중완료시간을 최소화하기 위해 아웃소싱 전략을 활용하는 일정계획문제

이익선(Ik Sun Lee) 한국경영과학회 2022 經營 科學 Vol.39 No.1

This paper researches a two-machine flowshop scheduling with an outsourcing strategy. In the flowshop, the first processing of jobs is either managed in-house or outsourced to outside suppliers, the second processing is processed in-house only. When a job is outsourced, the company pays outsourcing cost for each job, and considers outsourcing lead-time implying that the second processing can start after the lead-time. The objective cost function of this paper is the sum of the total weighted completion time and the outsourcing costs. This paper derives a branch-and-bound algorithm and some heuristics for the problem. From the computational experiments, we can observe that the performance of the derived algorithms is effective and efficient.

1차 관측기를 이용한 진동 저감의 PMSM 위치 제어에 대한 연구

이익선(Ik-Sun Lee),정성철(Sung-Chul Jung),윤인식(In-Sik Yoon),고종선(Jong-Sun Ko) 대한전기학회 2018 대한전기학회 학술대회 논문집 Vol.2018 No.-

PMSM(Permanent Magnet Synchronous Motor)은 반도체 공정, 로봇 공장 자동화 등 현재 산업 시스템에서 주로 사용하고 있으며, 이에 대한 연구도 활발히 진행되고 있다. 그러나 고정밀 제어를 위한 구동 방식에서 PMSM은 부하의 결합과정 또는 기구부와의 결합 시 기구부가 가지고 있는 고유 진동 주파수 성분으로 인해 기계계의 응답 특성은 매우 불안정해지고, 진동하는 현상이 발생한다. 본 논문에서는 PMSM을 이용한 정밀 위치 제어 시스템에서 기구부가 가지고 있는 진동하는 성분을 1차 데드비트 관측기(First Order Deadbeat Observer)를 이용하여 보상한다. 그 결과 기계부의 진동하는 현상이 감소함으로써, 제어 시스템이 정밀하고 강인해진다. 1차 테드비트 관측기의 성능을 검증하기 위해 추가 상태 궤환 제어기(Augmented State Feedback Control)와 0차 데드비트 관측기(Zero Order Deadbeat Observer)를 비교하였고, 그 결과 1차 데드비트 관측기가 더 강인하다는 것을 확인하였다. 이 제어 시스템의 알고리즘을 C언어와 Matlab을 사용하여 모의실험을 통해 검증하였다.

Strong NP-completeness of Single Machine Scheduling with Resource Dependent Release Times and Processing Times

Ik Sun Lee(이익선) 한국경영과학회 2014 經營 科學 Vol.31 No.2

This paper considers a single machine scheduling problem to determine release and processing times where both the release times and processing times are linearly decreasing functions of resources. The objective is to minimize the sum of the associated resource consumption cost and scheduling cost including makespan, sum of completion times, maximum lateness, or sum of lateness. This paper proves that the scheduling problem is NP-hard in the strong sense even if the release times are constant.

자체생산과 아웃소싱의 통합 생산일정계획 연구

이익선(Ik-Sun Lee),전재호(Jae-Ho Juhn),윤상흠(Sang-Hum Yoon) 한국산업경영학회 2010 經營硏究 Vol.25 No.4

본 연구의 목적은 제조업의 생산기능에서 아웃소싱수단이 존재하는 상황에서의 생산일정계획문제를 모델링하고 이에 대한 효율적인 해법을 제안하는 것이다. 즉, 개별 작업(또는 주문)의 처리가 자체생산설비를 통해 직접 수행되거나 외부설비(아웃소싱)에 위탁되어 조달되는 두 가지 선택이 모두 존재하는 경우에 수행해야 할 전체 작업에서 아웃소싱될 작업들에 대한 선택(job selection)과 전체 작업들에 대한 일정계획(job scheduling)을 동시에 결정하는 통합 의사결정 문제를 고려하고 있다. 자체생산설비와 외부설비는 각각 생산용량의 제약을 가지는 경우를 고려하였으며 어떤 작업이 자체설비를 통해 처리될 경우에는 해당 작업에 대한 일정계획비용(scheduling cost)이 발생하게 되고 그 작업을 아웃소싱하기로 결정할 경우에는 추가적인 아웃소싱 비용이 발생하게 된다. 본 연구에서는 총 아웃소싱비용에 대한 예산제약(budget constraint)이 존재하는 경우에 총 일정계획비용과 총 아웃소싱비용을 합한 전체 비용이 최소화 될 수 있는 아웃소싱 작업의 선택과 작업일정계획을 동시에 결정하게 된다. 해당 의사결정 문제는 NP-complete영역에 속한 문제로써, 최적해를 도출할 수 있는 동적계획법과 분지한계법, 그리고 큰 사이즈의 문제를 효율적으로 접근할 수 있는 발견적 해법을 동시에 제안한다. The objective of this paper is to present a new production scheduling model and an efficient method to solve the model in the case that there is an outsourcing option in the time-sensitive make-to-order environment. The orders(or, jobs) from customers can be either processed in a capacitated in-house facility or outsourced to subcontractors. Each job to be processed in-house induced the scheduling cost, otherwise the job is determined to be outsourced, then an additional outsourcing cost is imposed. This paper adopts the scheduling cost as the sum of completion times of all jobs. The objective of the scheduling model is to minimize the linear combination of scheduling and outsourcing costs under a budget constraint for the total available outsourcing cost in the capacitated in-house and outsourcing manufacturing environment. To solve the problem, we first should select jobs should be outsourced, and then we should determine both schedules for the in-house and outsourcing jobs. Thus, this problem considers an integrated decision problem for the job selection and sequencing. In the problem analysis, we first characterize some solution properties and then derive dynamic programming and branch-and-bound algorithms for the optimal solutions. An efficient heuristic is also developed because the problem belongs to the NP-complete context. The performances of the proposed optimal and heuristic algorithms are evaluated through various numerical experiments.

외란의 변화가 있는 PMSM의 강인하고 정밀한 위치 제어에 대한 연구

이익선(Ik-Sun Lee),여원석(Won-Seok Yeo),정성철(Sung-Chul Jung),박건호(Keon-Ho Park),고종선(Jong-Sun Ko) 대한전기학회 2018 전기학회논문지 Vol.67 No.11

Recently, a permanent magnet synchronous motor of middle and small-capacity has high torque, high precision control and acceleration / deceleration characteristics. But existing control has several problems that include unpredictable disturbances and parameter changes in the high accuracy and rigidity control industry or nonlinear dynamic characteristics not considered in the driving part. In addition, in the drive method for the control of low-vibration and high-precision, the process of connecting the permanent magnet synchronous motor and the load may cause the response characteristic of the system to become very unstable, to cause vibration, and to overload the system. In order to solve these problems, various studies such as adaptive control, optimal control, robust control and artificial neural network have been actively conducted. In this paper, an incremental encoder of the permanent magnet synchronous motor is used to detect the position of the rotor. And the position of the detected rotor is used for low vibration and high precision position control. As the controller, we propose augmented state feedback control with a speed observer and first order deadbeat disturbance observer. The augmented state feedback controller performs control that the position of the rotor reaches the reference position quickly and precisely. The addition of the speed observer to this augmented state feedback controller compensates for the drop in speed response characteristics by using the previously calculated speed value for the control. The first order deadbeat disturbance observer performs control to reduce the vibration of the motor by compensating for the vibrating component or disturbance that the mechanism has. Since the deadbeat disturbance observer has a characteristic of being vulnerable to noise, it is supplemented by moving average filter method to reduce the influence of the noise. Thus, the new controller with the first order deadbeat disturbance observer can perform more robustness and precise the position control for the influence of large inertial load and natural frequency. The simulation stability and efficiency has been obtained through C language and Matlab Simulink. In addition, the experiment of actual 2.5[kW] permanent magnet synchronous motor was verified.

제품조달시간을 고려한 주문처리 일정계획에 관한 연구

이익선(Ik Sun Lee),전재호(Jaeho Juhn),윤상흠(Sang Hum Yoon) 한국생산관리학회 2006 韓國生産管理學會誌 Vol.17 No.3

  본 연구는 주문일정계획문제에서 주문에 포함된 일부제품이 자체 생산되지 않고 외부의 협력업체를 통해 조달되는 경우를 고려하고 있다. 각 주문은 자체생산제품과 외부조달제품으로 구성되고, 자체생산제품에 대해서는 독자적인 생산일정계획이 필요하지만, 외부조달제품의 경우에는 외부에서 생산되며 제품의 도착시점이 바로 조달제품의 생산완료시점이 되는 것이다. 따라서 각 주문이 충족되는 시점은 각 주문에 포함된 모든 제품을 생산 및 조달하여 모두 완비되는 최초시점으로 모델링 된다. 본 연구는 이러한 상황에서 모든 고객주문을 충족시키는데 소요되는 총 가중완료시간(total weighted completion time)을 최소화하기 위한 생산일정계획문제를 다루고 있다. 문제의 분석에서 작업간의 우선순위관계를 규명할 수 있는 우월성질이 제시되고, 이를 바탕으로 분지한계법과 그리디 형태의 휴리스틱을 제안한다. 제안된 우월성질, 휴리스틱, 분지한계법의 성능은 다양한 수치데이터를 활용한 실험을 통해 평가된다.   This paper considers a scheduling problem to meet some orders from customers. Each order is composed of two types of products. One product is manufactured by a single facility under make-to-order environment, the other product is supplied from the outside facility(or, contractor), so given as an available time data. The completion time of each order is measured by the time when both of the corresponding products are completed(or, available). The problem is to obtain the optimal sequence of orders to minimize the total weighted completion time. In the problem analysis, we first derive a powerful property to determine the sequence of two consecutive orders. And then, two lower bounds of objective are derived and tested along with the derived property within a branch-and-boundscheme. An efficient heuristic algorithm based on a greedy manner is also developed. The overall performance of the proposed property, branchand-bound and heuristic is evaluated through numerical experiments.