International Journal of Advanced Operations Management (9 papers in press)
A hybrid lion optimization algorithm to solve the flexible job shop scheduling problems
by MARIAPPAN KADARKARAINADAR MARICHELVAM
Abstract: This paper addresses the ﬂexible job shop scheduling problem (FJSP) with makespan criterion. The FJSP has been proved to be strongly NP-hard. The FJSP is a generalization and extension of the classical job shop scheduling problem (JSP). As the problem is NP-hard, exact solution techniques cannot be used to tackle the problem. Researchers have proposed several heuristics and meta-heuristics to solve the problem. The lion optimization algorithm is one of the recently developed meta-heuristic algorithms. A hybrid lion optimization algorithm (HLOA) is proposed in the present work to solve the FJSP. A heuristic is hybridized with the LOA to improve the solution quality. To the best of our knowledge this is the first reported application of the LOA to solve the scheduling problems. The performance of the proposed algorithm is tested with two different sets of benchmark problems addressed in the literature. Computational results substantiate the effectiveness of the proposed algorithm.
Keywords: scheduling; flexible job shop; NP-hard; makespan; lion optimization algorithm.
Selection of optimal machining parameters using integrated MCDM approaches
by Mohammad Asjad, Faisal Talib
Abstract: In present work, the effect of three controllable parameters (table speed, feed per tooth and depth of cut) in a CNC milling machine on material removal rate and surface roughness have been investigated by three Multi Criteria Decision Making Techniques (MCDMs). Nine experiments as per Taguchis standard L9 orthogonal array were performed on the machine parameters of a CNC milling machine. Subsequently, multi-response optimization was performed using grey relational analysis (GRA), Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), and Multi-objective optimization by ratio analysis (MOORA) coupled with principal component analyses (PCA). The results revealed that the same optimal condition has been obtained by all the three techniques. Thus, it may be concluded that the three techniques behaves equally good for obtaining the optimal parameters of a CNC milling machine and these techniques are simple as well as effective for solving the multi-response optimization problem. This piece of research work will be helpful to academician, researchers, and other stakeholders in understanding the importance, severity and benefits obtained by the application, implementation and optimization of the controllable parameters of a CNC milling machine using GRA, TOPSIS and MOORA.
Keywords: CNC milling Machine; machining parameters; Grey relational analysis; TOPSIS; MOORA; Principal component analysis.
Key Performance Indicators versus Business Process Metrics
by Peter Schmidt, Jozef Stasak
Abstract: This paper deals with conceptual model of Business Process Linguistic Modelling Strategy Creator. There are discussed principal theoretical aspects concerned to its structure and functionality, especially business process performance quantification via KPI indicators and indicators, which create an integral part of business process internal and external metrics, as well as simulation and optimization capabilities, which that creator might provide within its functionality. However, that paper deals with structure and functionality elements of Business Process Linguistic Modelling Strategy Creator alone as well.rnrn
Keywords: business process linguistic modelling strategy creator; simulation aspects; optimization aspects.
Dynamic Integrated Planning of Empty Cars and Railroad in a Scheduled Service Network
by Mehdi Bagheri, Ali Namazian, Reza Babazadeh
Abstract: The management of empty cars in a railway network is one of the key factors in improving railway network performance and management of the railway facilities. This paper presents a novel mixed-integer linear programming (MILP) model to optimize the planning and scheduling of freight trains services, empty cars, and routs in a railroad network. In the proposed model, swapping between empty and loaded cars, classifying different empties and loaded cars, and blocking cars are considered to create efficient services with minimum total costs. A real case of railway network in Iran is conducted to verify and validate of the proposed model. Also, different scenarios are evaluated and sensitivity analysis is performed on the important and effective parameters of the developed model. The acquired results indicate that the proposed model could be efficiently used for planning and scheduling empty cars in real service networks.
Keywords: Freight transportation system; empty cars management; railway freight transportation; mathematical programming.
Airline Capacity Strategies: Worldwide Analysis, Taxonomies and Regional Comparison
by Saleh Alkhatib, Yazan Migdadi
Abstract: Airline capacity strategy is a crucial element of any airline operations management. However, there is no clear classification of airline capacity strategies, their taxonomies and how they differ across regions worldwide. Four stages methodology have been used: literature review content analysis, sample design, data collection/preparation and data analysis. Data for more than 350 airlines from six regions worldwide were collected, prepared and analyzed. The K-means clustering test was used for this purpose. Five main airline capacity strategies were identified and taxonomized: Low Capacity-Moderate Destination; Very-Low Capacity; Moderate Capacity-People focus; Low Capacity-Onboard focus; and Very-High Capacity-Selective Countries strategies. In addition, main capacity strategy patterns within each region were identified too. Moreover, a cross regional comparison identifies the key features, similarities and differences between regions. Finally, some suggestion for airlines were given.
Keywords: Airline industry; Capacity Strategies; Taxonomy; Operations management; K-means test.
DEVELOPMENT OF EFFICIENT GENETIC ALGORITHM FOR OPEN SHOP SCHEDULING PROBLEM TO MINIMIZE MAKESPAN
by ANAND ELLUR, PANNEERSELVAM R
Abstract: Scheduling problem deals with the management of the resources used in manufacturing systems in most optimal manner. In this research, open shop scheduling problem is considered. There are several real life situations, where open shop scheduling problem exists. The minimization of makespan of the open shop scheduling problem is considered in this research, because it is a dominant measure of performance among all the measures of performance. This problem comes under combinatorial category. Hence, development of an efficient heuristic is inevitable to minimize the makespan of the open shop scheduling problem. Among all the heuristic, genetic algorithm (GA), which is a meta-heuristic is considered, because it has the scope of improvement of the performance measure of the problem in terms of a combination of selection method, crossover method and mutation probability. The performance of the genetic algorithm is influenced by selection method, crossover operator and mutation probability. The objective of this research is to develop a set of genetic algorithms in terms of selection method, crossover operator and mutation probability and select the best genetic algorithm to minimize the makespan of the open shop scheduling problem. Four different genetic algorithm are developed by having different combinations of selection method and crossover operator and three of those algorithms uses the newly proposed crossover operator. A complete factorial experiment with three factors and three replications for each experimental combination is carried out on a set of problem instances with all the four Genetic algorithm (GA) methods, viz. three of them with proposed crossover operator and with one point crossover operator to compare the algorithms.
Keywords: Open shop scheduling problems; Flow shop scheduling problem; Job shop scheduling problems; Three-chromosome Juggling Crossover Operator; TCJC; Genetic algorithm; Makespan; Crossover operators; Mutation; Factorial design; ANOVA; Duncan Tests.
Developing a Time-Cost Trading-Off Model for Construction Projects in Fuzzy Environment (Case study: Weigh in Motion System)
by Solmaz Salehzadeh, Abbas Mahmoudabadi
Abstract: Completion time, an important issue on construction projects with limited practical duration, is usually studied comparing to construction or implementation cost. In this research work, the fuzzy behavior of cost and time for project activities has been investigated based on predicted completion time followed by developing a mathematical model for making a trade-off approach for project planning. Objective function is to minimize project cost which is defined in discrete and continuous domains considering limited implementation time. According to the constraints, a non-linear model was developed, so a linearization technique has been utilized to convert that to linear. In addition, an acceptable range of changes (tolerance) is considered for the project completion time to achieve better solutions followed by making a sensitivity analysis process on results of time-cost trading off approach. Installing a Weigh In Motion system (WIM), in the central Iranian road of Isfahan-Naein, has been selected as case study and the proposed model has been validated using experimental data. Results revealed that the proposed model, which has been converted to linear, is capable to perform a time-cost trading off approach for projects those dont have exact time and cost for project activities.
Keywords: Project Management; Time-cost trade off; Linearization; Mathematical Modeling.
SIMULATION MODELING AND ANALYSIS OF DISPATCHING RULES IN AN ASSEMBLY JOB SHOP PRODUCTION SYSTEM WITH MACHINE BREAKDOWNS
by Midhun Paul, Radha Ramanan T, Sridharan R
Abstract: This paper addresses the scheduling problem in assembly job shop systems with machine breakdowns. The present study intends to rank the dispatching rules that are applied in an assembly job shop production system. A simulation model of an assembly job shop is developed for the purpose of this ranking and eight dispatching rules from the literature are incorporated in the simulation model. The product structures considered in this study are single-level assembly structure, two-level assembly structures and three level assembly structures. The machines are subjected to non-availability due to of breakdowns. Five performance measures are considered for analysis. The performance of each dispatching rule for each performance measure is calculated individually. To identify which of the dispatching rule provides the optimum result when all the performance measures are equally important, grey relational analysis is adopted to rank the dispatching rules. The results indicate that earliest completion time rule performs better in comparison with the other rules investigated in this study for single-level structure with multiple objectives.
Keywords: Assembly Job Shop; Dispatching Rules; Simulation; Multi-Objective; machine breakdowns; Grey Relational Analysis.
Feasibility Analysis of FMS in Small and Medium Scale Indian Industries with a Hybrid approach using ISM and TOPSIS
by Sandhya Dixit, Tilak Raj
Abstract: Small and medium scale industries play an important role in Indian economy and their strength lies in the competitiveness of their products in the world market. Backed by a strong government support in India, they continue to improve their growth rate. Despite this high growth rate, huge potential amongst the Indian small and medium scale industries still remains untapped. So there is a need to upgrade these industries so that they bloom to their full potential. For achieving increased competitiveness, the manufacturing SMEs need to replace or supplement their previous methods of production with more flexible and dynamic production systems like, Flexible manufacturing system (FMS) which is characterized by shorter product development and manufacturing lead-time, better quality and flexibility, team based work organizations, low setup/changeover times, multifunctional workers. But the FMS is not well adopted in Small and Medium Enterprises. FMS as a manufacturing strategy can help a SME to improve its processes and align it to the requirements of its customers. So this paper discusses the issues of SMEs and presents the major attributes for the adoption of FMS in SMEs and further these attributes are modelled to give a structure amongst them by using two distinct, well established modelling techniques, ISM and TOPSIS.
Keywords: Small and Medium Scale Industries; Flexible Manufacturing Systems; Attributes; MADM; Interpretive Structural Modelling; TOPSIS.