การจัดตารางการผลิตสำหรับระบบการผลิตแบบไหลเลื่อนยืดหยุ่นโดยมีเวลาปรับตั้งเครื่องจักรซึ่งขึ้นกับลำดับงานภายใต้นโยบายการผลิตแบบทันเวลาพอดี

บทคัดย่องานวิจัยนี้ศึกษาการจัดตารางการผลิตสำหรับระบบการผลิตแบบไหลเลื่อนยืดหยุ่น (Flexible Flow Shop Scheduling) ซึ่งมีนโยบายการผลิตแบบทันเวลาพอดี (Just-In-Time Philosophy) ในงานวิจัยกำหนดให้มีงาน n งานมีกำหนดส่งมอบงานแตกต่างกันและมีเวลาปรับตั้งเครื่องจักรซึ่งขึ้นกับลำดับงาน (Sequence Dependent Setup Time) ถูกทำการผลิตผ่านขั้นตอนการดำเนินงาน (Operation) จำนวน L ขั้นตอนในแต่ละขั้นตอนประกอบด้วยระบบเครื่องจักรแบบขนานที่ไม่มีความสัมพันธ์กัน (Unrelated Parallel Machines) วัตถุประสงค์ของงานวิจัย คือการจัดตารางการผลิตเพื่อลดค่าใช้จ่ายรวมของระบบ (Total System Cost) ซึ่งประกอบด้วยค่าใช้จ่ายจากงานเสร็จก่อนกำหนด (Earliness Cost) และค่าใช้จ่ายจากงานเสร็จล่าช้า (Tardiness Cost) ในงานวิจัยกำหนดการเชิงเส้นจำนวนเต็ม (Integer Linear Programming) ถูกสร้างขึ้นเพื่อแสดงคุณลักษณะของปัญหาและใช้หาคำตอบที่ดีสำหรับปัญหาดังกล่าว กระบวนการฮิวริสติกถูกพัฒนาขึ้นโดยประกอบด้วย 3 ขั้นตอนหลัก ขั้นตอนที่หนึ่งเป็นการสร้างลำดับของงาน ขั้นตอนที่สองทำการกระจายงานเข้าสู่เครื่องจักรแต่ละเครื่อง และในขั้นตอนสุดท้ายเป็นการหาเวลาที่เหมาะสมในการเริ่มและสิ้นสุดของงานแต่ละงานบนเครื่องจักรแต่ละเครื่อง จากการเปรียบเทียบคำตอบที่ได้จากวิธีการฮิวริสติกกับคำตอบที่ดีที่สุดจากกำหนดการเชิงเส้นจำนวนเต็มพบว่าจากปัญหาตัวอย่าง 45 ปัญหา กระบวนการฮิวริสติกสามารถให้คำตอบที่ดีในระยะเวลาการประมวลผลสั้นกว่าการหาคำตอบจากกำหนดการเชิงเส้นจำนวนเต็มโดยมีค่าความแตกต่างเฉลี่ยจากคำตอบที่ดีที่สุดไม่เกินสองเปอร์เซ็นต์คำสำคัญ: ระบบการผลิตแบบไหลเลื่อนยืดหยุ่น การจัดตารางการผลิต ระบบการผลิตแบบทันเวลาพอดีAbstractThe research considers the flexible flow-shop scheduling under the production system of Just-In-Time (JIT) philosophy. In the study, there are n jobs with sequence dependent setup time and different due dates waiting to be processed through L operations. Each operation can be conducted on a set of unrelated parallel machines. The research objective is to determine the job schedule with lower total system cost composing of earliness and tardiness costs. This study employed the mathematical model based on the integer linear programming concept. A heuristic is created to determine the proper solution to the problem. The heuristic can be divided into three major steps. The first step is to create a job sequence. For each job sequence obtained from the first step, the second step is to assign each job to each machine corresponding to its operation. Finally, the starting and completion times of each job in each operation is calculated according to the optimal timing algorithm developed in the research. In order to evaluate the performance of the proposed heuristic, the solution obtained from the heuristic is compared to the optimal solution determined by integer linear programming. From the result of 45 problems, the heuristic can provide the good solution with shorter amount of time than using integer linear programming with the average error less than 2% from the optimal solution.Keywords: Flexible Flow Shop, Scheduling, Just-In-Tim

Integer Batch Scheduling Problems for a Single-Machine to Minimize Total Actual Flow Time

AbstractThis research addresses a batch scheduling model for a single-machine under a Just-In-Time (JIT) production system that produces discrete parts. The objective is to minimize the total actual flow time, defined as the time when parts are flowing on the shop floor from its arrival time to their common delivery time. The decision variables are the number of batches, integer batch sizes, and the sequence of the resulting batches. The problem is solved based on the Lagrange Relaxation method. The optimality test of the proposed algorithm is done by comparing the result of the proposed algorithm with the Integer Composition method. The result of numerical experiments demonstrates that the proposed algorithm is very efficient to solve the problems

A memetic algorithm to minimize the total sum of earliness tardiness and sequence dependent setup costs for flow shop scheduling problems with job distinct due windows

The research considers the flow shop scheduling problem under the Just-In-Time (JIT) philosophy. There are n jobs waiting to be processed through m operations of a flow shop production system. The objective is to determine the job schedule such that the total cost consisting of setup, earliness, and tardiness costs, is minimized. To represent the problem, the Integer Linear Programming (ILP) mathematical model is created. A Memetic Algorithm (MA) is developed to determine the proper solution. The evolutionary procedure, worked as the global search, is applied to seek for the good job sequences. In order to conduct the local search, an optimal timing algorithm is developed and inserted in the procedure to determine the best schedule of each job sequence. From the numerical experiment of 360 problems, the proposed MA can provide optimal solutions for 355 problems. It is obvious that the MA can provide the good solution in a reasonable amount of time

Scheduling of non-repetitive lean manufacturing systems under uncertainty using intelligent agent simulation

World-class manufacturing paradigms emerge from specific types of manufacturing systems with which they remain associated until they are obsolete. Since its introduction the lean paradigm is almost exclusively implemented in repetitive manufacturing systems employing flow-shop layout configurations. Due to its inherent complexity and combinatorial nature, scheduling is one application domain whereby the implementation of manufacturing philosophies and best practices is particularly challenging. The study of the limited reported attempts to extend leanness into the scheduling of non-repetitive manufacturing systems with functional shop-floor configurations confirms that these works have adopted a similar approach which aims to transform the system mainly through reconfiguration in order to increase the degree of manufacturing repetitiveness and thus facilitate the adoption of leanness. This research proposes the use of leading edge intelligent agent simulation to extend the lean principles and techniques to the scheduling of non-repetitive production environments with functional layouts and no prior reconfiguration of any form. The simulated system is a dynamic job-shop with stochastic order arrivals and processing times operating under a variety of dispatching rules. The modelled job-shop is subject to uncertainty expressed in the form of high priority orders unexpectedly arriving at the system, order cancellations and machine breakdowns. The effect of the various forms of the stochastic disruptions considered in this study on system performance prior and post the introduction of leanness is analysed in terms of a number of time, due date and work-in-progress related performance metrics

Framework for sustainable TVET-Teacher Education Program in Malaysia Public Universities

Studies had stated that less attention was given to the education aspect, such as teaching and learning in planning for improving the TVET system. Due to the 21st Century context, the current paradigm of teaching for the TVET educators also has been reported to be fatal and need to be shifted. All these disadvantages reported hindering the country from achieving the 5th strategy in the Strategic Plan for Vocational Education Transformation to transform TVET system as a whole. Therefore, this study aims to develop a framework for sustainable TVET Teacher Education program in Malaysia. This study had adopted an Exploratory Sequential Mix-Method design, which involves a semi-structured interview (phase one) and survey method (phase two). Nine experts had involved in phase one chosen by using Purposive Sampling Technique. As in phase two, 118 TVET-TE program lecturers were selected as the survey sample chosen through random sampling method. After data analysis in phase one (thematic analysis) and phase two (Principal Component Analysis), eight domains and 22 elements have been identified for the framework for sustainable TVET-TE program in Malaysia. This framework was identified to embed the elements of 21st Century Education, thus filling the gap in this research. The research findings also indicate that the developed framework was unidimensional and valid for the development and research regarding TVET-TE program in Malaysia. Lastly, it is in the hope that this research can be a guide for the nations in producing a quality TVET teacher in the future

A Neighborhood Search for Sequence-dependent Setup Time in Flow Shop Fabrics Making of Textile Industry

Abstract This paper proposes a neighborhood search to solve scheduling for fabrics making in a textile industry. The production process consists of three production stages from spinning, weaving, and dyeing. All stages have one processor. Setup time between two consecutive jobs with different color is considered. This paper also proposes attribute’s decomposition of a single job to classify available jobs to be processed and to consider setup time between two consecutive jobs. Neighborhood search (NS) algorithm is proposed in which the permutation of set of jobs with same attribute and the permutation among set of jobs is conducted. Solution obtained from neighborhood search, which might be trapped in local solution, then is compared with other known optimal methods

Parameterized complexity of machine scheduling: 15 open problems

Machine scheduling problems are a long-time key domain of algorithms and complexity research. A novel approach to machine scheduling problems are fixed-parameter algorithms. To stimulate this thriving research direction, we propose 15 open questions in this area whose resolution we expect to lead to the discovery of new approaches and techniques both in scheduling and parameterized complexity theory.Comment: Version accepted to Computers & Operations Researc

Design and operational control of an AGV system

In this paper we first deal with the design and operational control of Automated Guided Vehicle (AGV) systems, starting from the literature on these topics. Three main issues emerge: track layout, the number of AGVs required and operational transportation control. An hierarchical queueing network approach to determine the number of AGVs is decribed. Also basic concepts are presented for the transportation control of both a job-shop and a flow-shop. Next we report on the results of a case study, in which track layout and transportation control are the main issues. Finally we suggest some topics for further research