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About 4,025 papers for “operation sequencing”

Operation sequencing and machining economics

Christos Koulamas · International Journal of Production Research · 1993

Abstract Solution techniques for the combined machining economics-operations sequencing problem are proposed. We examine the problem of determining the sequence and the cutting speeds for a number of operations performed using the same tool, where the independently calculated optimal cutting speeds differ among operations. The essence of the proposed solution method is that it may be beneficial to perform some operations at non-optimal speeds in order to reduce the cost associated with speed changes. The problem is initially formulated as a continuous nonlinear optimization problem combined with a discrete combinatorial scheduling problem. After the problem is descretized, an efficient heuristic technique (the overlapping speed ranges (OSR) heuristic) is proposed for finding good solutions to the problem quickly. The heuristic determines the cutting speeds and the sequencing of operations utilizing the indifference speed ranges which are based on the sensitivity of the operations' unit machining costs to the speed change cost. A branch and bound algorithm is also proposed for finding optimal solutions to the problem. The branch and bound algorithm performs extremely well because it utilizes as a strong upper bound the complete solution provided by the OSR heuristic, and because tight lower bounds are computed for all nodes throughout the branching procedure. Finally, for large problems a heuristic variant of the branch and bound procedure is suggested (the filtered beam search method which does not backtrack).

Cited by 21

Operation sequencing in a FMS

A. S. Carrie, A. C. Petsopoulos · Robotica · 1985

SUMMARY In simulation studies of an FMS serious congestion problems were observed. Since they had not occurred in earlier FM systems built by the same manufacturer comprising similar machines and control software, it was concluded that they must be caused by the nature of the operation sequences and times of the parts to be produced. This paper reports the results of experiments to assess the dependence of the system's performance on the sequence in which jobs are launched, the relative times of successive operations, machine groupings and product mix. The principal performance measures were the production achieved within a certain time period and the ratio for each part of its processing time to its time in the system. The results are presented, and, contrary to expectation, in most cases there were no statistically significant effects. The possible reasons for and implications of the results are discussed.

Cited by 26

Automatic-Sequencing Equipment for Television Operation

F. Cecil Grace, Charles E. Spicer · Journal of the SMPTE · 1961

An automatic television program system has been designed wherein events are stored in beam switching tube memory elements, along with the time each event is to remain on the air. As each event goes on the air, its time begins to count down 10–9–8–7, etc., to zero. When it reaches zero the next event is automatically switched on the air and its allotted time starts counting down. In case the operator desires to cut short an event which is on the air before its allotted time expires he may do so and immediately place the next upcoming event on the air by pushing a “take” button on his control panel. Similarly if he desires to extend the allotted time of an event on the air he may push a “hold” button which will stop the countdown, allowing the on-air event to continue until he is ready to put the next event on the air, which he does by pushing the “take” button. This provides split second automatic timing with straightforward manual override.

Cited by 3

Operation sequencing in CAPP using genetic algorithms

Reddy Sreenivasulu · International Journal of Production Research · 1999

Computer aided process planning (CAPP) is an important interface between computer aided design (CAD) and computer aided manufacturing (CAM) in computer integrated manufacturing (CIM). Operation sequencing in process planning is concerned with the selection of machining operations in steps that can produce each form feature of the part by satisfying relevant technological constraints specified in the part drawing. A single sequence of operations may not be the best for all the situations in a changing production environment with multiple objectives such as minimizing number of set-ups, maximizing machine utilization and minimizing number of tool changes. This paper demonstrates the application of genetic algorithms as a global search technique for a quick identification of optimal or near optimal operation sequences in a dynamic planning environment. A novel initialization scheme for representing the genetic code and a new crossover operator are designed to retain the local operation precedence for each form feature. Since sequences can be obtained quickly, this approach can actually be used by the process planner to generate alternative feasible sequences for the prevailing operating environment.

Cited by 103

Otoplasty: Sequencing the Operation for Improved Results

James G. Hoehn, Salman Ashruf · Plastic & Reconstructive Surgery · 2005

: After studying this article, the participant should be able to: 1. Understand the anatomy and embryology of the external ear. 2. Understand the anatomic causes of the prominent ear. 3. Understand the operative maneuvers used to shape the external ear. 4. Be able to sequence the otoplasty for consistent results. 5. Understand the possible complications of the otoplasty procedure. Correction of prominent ears is a common plastic surgical procedure. Proper execution of the surgical techniques is dependent on the surgeon's understanding of the surgical procedure. This understanding is best founded on an understanding of the historical bases for the operative steps and the execution of these operative steps in a logical fashion. This article describes the concept of sequencing the operation of otoplasty to produce predictable results combining the technical contributions from many authors. The historical, embryological, and anatomic bases for the operation are also discussed. Finally, the authors' preferred techniques are presented. Sequencing the steps in the preoperative assessment, preoperative planning, patient management, operative technique, and postoperative care will produce reproducible results for the attentive surgeon. Careful attention to the details of the operation of otoplasty will avoid many postoperative problems.

Cited by 35

Operation Sequencing Using Ant Colony Optimization Technique

Pramod Kumar Jain, V.K. Gupta · 2006

The operation-sequencing problem in process planning is considered to produce a part with the objective of minimizing the sum of machine, setup and tool change costs. In general, the problem has combinatorial characteristics and complex precedence relations, which makes the problem difficult to solve. In this paper ant colony optimization technique has been used to solve this sequencing problem. Present approach analyses the precedence relationships among features to generate a precedence relationship matrix (PRM).

Cited by 4

An Integrated Operation Sequencing and Tool Selection Algorithm

Anas Ma’ruf · Transactions of the Institute of Systems Control and Information Engineers · 2000

In this study, a new heuristic method is proposed involving a non-recursive algorithm and priority rules to integrate the operation sequencing and tool selection phase in a CAM system. The object of the algorithm is to automatically define the operation sequence and tool to be used for each operation while minimizing the number of tool changes and the total number of tools. As an effective method for reducing tool preparatory task, resident tool practice is accommodated by comparing accumulated frequency record of the past use of candidate tools. A numerical example has been provided in this study. Also, the proposed algorithm is compared with other known algorithms and its advantages examined.

Cited by 0Open access

Granulation Enhancement in Anaerobic Sequencing Batch Reactor Operation

Say Leong Ong, Jiangyong Hu, Wun Jern Ng et al. · Journal of Environmental Engineering · 2002

Two laboratory-scale anaerobic sequencing batch reactors (anSBRs) were used to investigate the effectiveness of polymer addition for enhancing granulation. Mixed liquor volatile suspended solids (MLVSS) concentrations in R1 (with a polymer supplement) and R2 (control) were maintained at approximately 5 g/L. Granule development was measured by determination of the average bioparticle diameter of biosolids from the anSBRs. Addition of cationic polymer to R1 started on the 47th day after reactor start-up at a dosage of 1 ppm (on reactor volume) once per every two cycles. The cationic polymer had a beneficial effect on granulation. Compared to the control, it shortened the granulation process by approximately four months. Within the range investigated, food-to-microorganism (F/M) ratios at 0.5–0.6 g COD/g VSS d were also beneficial to granulation. After 300 days operation (at F/M ratio 0.5 g COD/g VSS d), the average bioparticle diameter of R1 was 0.78 mm, while R2 was only 0.39 mm. R1, aside from having a larger granule size, also had a higher methane production and lower soluble COD in effluent at F/M ratio 0.6 g COD/g VSS d compared to R2.

Cited by 11

SEQUENCING BATCH REACTORS: PRINCIPLES, DESIGN/OPERATION AND CASE STUDIES

M. Sundaravadivel, D. S. Chaudhary, S. Vigneswaran · 2007

1. Background 2. The SBR technology for wastewater treatment 3. Physical description of the SBR system 3.1 FILL Phase 3.2 REACT Phase 3.3 SETTLE Phase 3.4 DRAW or DECANT Phase 3.5 IDLE Phase 4. Components and configuration of SBR system 5. Control of biological reactions through operating strategies 6. Design of SBR reactor 7. Costs of SBR 8. Case studies 8.1 Quakers Hill STP 8.2 SBR for Nutrient Removal at Bathhurst Sewage Treatment Plant 8.3 St Marys Sewage Treatment plant 8.4 A Small Cheese-Making Dairy in France 8.5 A Full-scale Sequencing Batch Reactor System for Swine Wastewater Treatment, Lo and Liao (2007) 8.6 Sequencing Batch Reactor for Biological Treatment of Grey Water, Lamin et al. (2007) 8.7 SBR Processes in Wastewater Plants, Larrea et al (2007) 9. Conclusion Glossary Bibliography Biographical Sketches

Cited by 1

Optimal operation planning and sequencing: minimization of tool changeovers

Cheng-Jung Lin, Hsu‐Pin Wang · International Journal of Production Research · 1993

Abstract Process planning is divided into two major tasks: routeing planning and operation planning. For operation planning a two-phase problem solving structure is proposed. In phase I, we focus on selection of process plans for a group of parts to be machined for the next planning cycle. It is formulated and solved as a dynamic programming problem. In phase II, we select and sequence operations and tools for those process plans. To this end, two 0–1 integer programming models are formulated and solved. A numerical example is presented to illustrate the problem solving steps.

Cited by 47

Automatic Setup Planning and Operation Sequencing for Satisfying Tolerance Requirements

Yuguang Wu, ShengJie Gao, Zichen Chen · 2001

Abstract In this paper, a novel approach to automatic setup planning and operation sequencing of a part is proposed. The critical tolerance feature sets of the part are first identified by comparing the tolerance specifications with the capabilities of machine tools. Then, based on the concepts of critical tolerance feature set, the feature model of the part is decomposed into a series of identical setup feature (ISF) sets, each of which corresponds to a setup candidate. Finally, according to geometric precedence and tolerance precedence among features, the reasonable machining operations of features with multiple machining operations are determined, the ISF sets are sequenced and merged. Compared to previous work, the approach can generate the setup plan by which the part can be machined to satisfy the required tolerances. The approach also has high efficiency.

Cited by 2

Path-relinking Grey Wolf Optimizer for Solving Operation Sequencing Problem

Shuai Wang Nappu, Jianping Dou Nappu, Canran Zhang · 2022 IEEE International Conference on Mechatronics and Automation (ICMA) · 2022

The operation sequencing problem in part process planning is one of the key issues of computer-aided process planning. This paper proposed a new grey wolf optimizer combined with Path-relinking (PR-GWO) to solve the operation sequencing problem in process planning to minimize the processing cost. The characteristic of PR-GWO algorithm is that it only searches for feasible operation sequences (FOSs), and it uses a graph algorithm to obtain the lowest-cost resources of every operation for a given sequence. Because of the one-to-one map between the FOS and its minimum cost, PR-GWO avoids updating the resource configuration of the process during the search process, and improves the search efficiency of the PRGWO and the global optimization capability. In addition, the local search capability of the algorithm is strengthened by adding Path-relinking to GWO. The proposed PR-GWO is compared with the latest existing genetic algorithm, particle swarm algorithm and ant colony algorithm in four cases. The comparative results show the effectiveness and advantages of PRGWO.

Cited by 1

Sequencing batch biofilm reactor: from support design to reactor operation

Maria Auxiliadora Costa Matos, C.F. Almeida Alves, José Luis Campos et al. · Environmental Technology · 2011

The aim of this work was to improve the overall understanding of sequencing batch biofilm reactors (SBBRs) from support selection (biofilm formation) to reactor operation (carbon and nitrogen removal). Supports manufactured with different materials and geometries were tested in 2.5 L SBBRs and it was observed that biofilm accumulation was favoured on the supports that presented a higher internal surface area. The geometry of the supports and the hydrodynamic conditions established in the SBBRs seemed to play a more important role in biofilm formation than the thermodynamic interaction, expressed as free energy of adhesion (deltaG), between the support material and the biomass. The support that presented the highest biofilm accumulation per unit of surface area (DupUM) was used in a 28 L SBBR and it was observed that, along a typical SBBR cycle, time profiles of nitrogen compounds showed the typical behaviour of nitrification and denitrification reactions. During the fill phase (without aeration) acetate was simultaneously consumed in biomass growth and denitrification. Immediately after the beginning of the aeration phase (without influent addition), acetate was depleted from the liquid phase and stored as poly-beta-hydroxybutyrate that was later on used in the growth of biomass, owing to the high oxygen concentration in the reactor.

Cited by 16