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Papers by S. Satoglu

International Journal of Disaster Risk Reduction, 2019

Computers & Industrial Engineering, 2017

Expert Systems with Applications, 2016

Assembly lines are mass production system which improve productivity, flexibility and production ... more Assembly lines are mass production system which improve productivity, flexibility and production quality in industrial systems. Compared to traditional straight lines and parallel lines, U-shaped assembly lines have lots of advantages in terms of performance of workers and production system. Especially, by means of U-shaped layout, improved balancing of assembly lines can be achieved. Moreover, the implementation of Lean Manufacturing and Just in Time Production (JIT) systems entail U-shaped assembly line (Chiang, 2006). One-piece flow which significantly reduces manufacturing lead times is facilitated by this type of facility layout. Multi skilled workers can handle more than one machine in U-shaped assembly lines. An important issue in U-shaped line balancing problem is the consideration of human factors. There are a small number of studies about human factors in the literature. Some of the factors are the learning effect (Biskup, 1999; Toksari et al., 2008) and task time variability due to human factors (Becker and Scholl, 2006; Chiang and Urban, 2006). The purpose of this study is developing a methodology for balancing U-shaped assembly lines while considering the human factors to improve productivity of the production system. Keywords U-shaped line balancing, just in time production, human factors

Journal of Intelligent Manufacturing, 2015

International Journal of Disaster Risk Reduction, 2020

Devastating effects of disasters and global crises on people increase the importance of humanitar... more Devastating effects of disasters and global crises on people increase the importance of humanitarian logistics studies for pre and post-disaster stages. Location planning of Temporary Medical Centers/field hospitals is one of the most important problems for disaster response. We aimed to determine the location and number of temporary medical centers in case of disasters by considering the locations of the existing hospitals, casualty classification (triage), capacities of medical centers and possibilities of damage to the roads and hospitals. Besides, we aimed to assign different casualty classes to these medical centers for emergency medical response by considering the distances between disaster areas and medical centers. For this purpose, a two-stage stochastic programming model was developed. The proposed model finds an optimal TMC location solution while minimizing the total setup cost of the TMCs and the expected total transportation cost by considering casualty types, demand, ...

Cellular Manufacturing Systems: Recent Developments, Analysis and Case Studies, 2017

Many manufacturing plants are subjected to increased market demand for short product delivery lea... more Many manufacturing plants are subjected to increased market demand for short product delivery lead times. In addition, shorter product life cycles and increased customization have reduced the chance of inventory holding to satisfy these conditions. That being the case, assembly cells are widely used in modern real life systems, since they provide an environment that can quickly manufacture, assemble and deliver small batches of customized products in a cost-effective manner. In this chapter, first the literature for assembly cells and walking worker assembly systems is reviewed. Then, a methodology for the conversion of conventional assembly systems to assembly cells is developed. Three different assembly cell configurations that lead to one-piece flow are designed and the initial configuration was implemented in a piezo igniter assembly system. The configurations are considered and compared under two different demand scenarios. Furthermore, the results of the implementation showed the obstacles and opportunities for such an overall conversion. The other two configurations will be implemented in near future.

In this study, a goal-programming model is proposed for the design of hybrid cellular manufacturi... more In this study, a goal-programming model is proposed for the design of hybrid cellular manufacturing (HCM) systems, in a dual resource constrained environment, considering many real-world application issues. The procedure consists of three phases. Following an initial phase involving a Pareto analysis of demand volumes and volatility, a machine-grouping phase is conducted to form manufacturing cells, and a residual functional layout. In this phase, over-assignment of parts to the cells, machine purchasing cost, and loss of functional synergies are attempted to be minimized. Following the formation of cells and the functional layout, a labor allocation phase is carried out by considering worker capabilities and capacities. The total costs of cross-training, hiring, firing and over-assignment of workers to more than one cell are sought to be minimized. An application of the model on real factory data is also provided in order to demonstrate the utility and possible limitations. The industrial problem was solved using professional mathematical programming software.

The companies utilize the development of the manufacturing technology to improve efficiency and p... more The companies utilize the development of the manufacturing technology to improve efficiency and performance of the operation by automating their production system. The robotic system is used to achieve the goals for manufacturing process reengineering. Due to the complexity of the robotic system, the determination of the robot arm as a subsystem is an effective way to begin the design process of the complete system. However, due to the increase in the number of robot arm alternatives, and existence of the multiple and conflicting criteria, it becomes hard to the decision makers to select the appropriate robot arm for the production system. Therefore, a methodology based on Axiomatic Design principles is proposed to help the decision maker to decide the appropriate robot arm in a scientific and systematic basis. Some terminology and calculation belonging to the Axiomatic Design is modified according to the structure of robot selection criteria. Then, the proposed methodology is extended into a decision support system (DSS) to evaluate more alternatives rapidly. The proposed DSS was applied to a real robot arm selection problem of a food manufacturing system in order to reveal its utility in evaluating and choosing the most suitable robot arm among several alternatives, in a fast manner.

As the U-shaped assembly lines are concerned with manual assembly operations, workers’ performanc... more As the U-shaped assembly lines are concerned with manual assembly operations, workers’ performance plays a major role. However, the past studies assume that all workers can carry out all tasks with an equal performance level, and actual task times do not depend on the worker who performs it. On the other hand, this is unrealistic. In this study, maximization of the line efficiency for the U-shaped assembly line worker assignment and balancing problem by considering the worker performance is aimed. First, a non-linear model of the problem is formulated, and then it is linearized. Later, an Artificial Bee Colony Algorithm and a Genetic Algorithm are proposed to solve it, in short computational times. A hypothetical data set (Jackson, 1956), a real data set (Cevikcan et al., 2009) and data sets of assembly line worker assignment and balancing problem (Araújo et al., 2015) were solved by using the model and the meta-heuristics. The meta-heuristics were able to reach solutions that have equal line efficiency with the optimum solution found by the proposed mathematical model. The contribution of this study is that the mathematical model for the U-shaped line assembly line worker assignment and balancing type-E problem that considers the workers’ performance is formulated, and an Artificial Bee Colony Algorithm is proposed for the first time for this problem type.

One-piece flow is a design rule that entails production in manufacturing cells on a 3 make one, c... more One-piece flow is a design rule that entails production in manufacturing cells on a 3 make one, check one, and move-on one basis (Black 2007), which reduces manufacturing lead 4 time, significantly. This paper proposes a Sequential Methodology comprised of a 5 mathematical model and a Heuristic Approach (HA) for the design of a Hybrid Cellular 6 Manufacturing System (HMS), to facilitate one-piece flow practice. The mathematical model is 7 employed in the cases of small and medium size problems, and it attempts to minimize the total 8 number of exceptional operations, while considering machine capacities and alternative 9 machines. The machine-part matrix achieved by the mathematical model is input into the flow 10 line design stage of the HA, where backflow within the cells is eliminated. However, for 11 industrial problems, the proposed HA is utilized. After the formation of the cells by clustering, 12 the HA attempts to eliminate exceptional operations of a given cellular configuration together 13 with a functional structure, by employing alternative machines, based on the decision rules 14 developed. Later, unidirectional flow within the cells is achieved and the capacity and budget 15 constraints are satisfied. A medium-sized problem is solved by using both of the approaches, 16 namely, the model integrated with the flow-line design stage of the HA and the complete HA. 17 The results are discussed and the limitations are explained. 18 19

Most of the production systems, which are arranged according to cellular manufacturing, have stil... more Most of the production systems, which are arranged according to cellular manufacturing, have still been using central storage sites as a continuation of their past habits and they have been supplying materials and parts to the manufacturing cells from these sites. This both violates the independence of the cells from the entire production system in terms of facilities and prevents the reduction of both materials and parts transportation. The structure with mini storage facilities, which are located very close to the cells and serve in connection with the cells in a decentralized manner, has many benefits in comparison with the structure of the central storage. However, estimating the economic value of the decentralized approach is not easy because of the difficulties of measuring non-value adding activities. In order to provide decision support for conversion to the decentralized mini storages, a methodology based on an activity-based costing (ABC) model was developed. The methodology was also evaluated with an example.

The p-median problem is one of the most well-known facility location problem and have several app... more The p-median problem is one of the most well-known facility location problem and have several applications in transportation, distribution, location of public, warehouses etc. The objective is to locate p facilities (medians) such that the sum of the distances from each demand point to its nearest facility is minimized. The p-median problem is well known to be NP-hard and several heuristics have been developed in the literature, but there are few applications of genetic algorithms for this problem. In this study, a new genetic algorithm approach to solve uncapacitated p-median problem is proposed. The parameters of the genetic algorithm are tuned using design of experiments approach. The proposed algorithm is tested on several instances of benchmark data set and evaluated with optimal solutions of the problems.

International Journal of Production Research, 2011

... Finally, using simulation models, it is shown that applying the proposed model results in a .... more ... Finally, using simulation models, it is shown that applying the proposed model results in a ... formulated the cell formation problem for a HMS design as a fuzzy multi-objective ... a roadmap for a complete HMS design, considering several design problems in an integrated way, using ...

articles by S. Satoglu

Abstract The lexicographic bottleneck assembly line balancing problem is a recently introduced pr... more Abstract The lexicographic bottleneck assembly line balancing problem is a recently introduced problem which aims at obtaining a smooth workload distribution among workstations. This is achieved hierarchically. The workload of the most heavily loaded workstation is minimised, followed by the workload of the second most heavily loaded workstation and so on. This study contributes to knowledge by examining the application of the lexicographic bottleneck objective on mixed-model lines, where more than one product model is produced in an inter-mixed sequence. The main characteristics of the lexicographic bottleneck mixed-model assembly line balancing problem are described with numerical examples. Another contribution of the study is the methodology used to deal with the complex structure of the problem. Two effective meta-heuristic approaches, namely artificial bee colony and tabu search, are proposed. The parameters of the proposed meta-heuristics are optimised using response surface methodology, which is a well-known design of experiments technique, as a unique contribution to the expert and intelligent systems literature. Different from the common tendency in the literature (which aims to optimise one parameter at a time), all parameters are optimised simultaneously. Therefore, it is shown how a complex production planning problem can be solved using sophisticated artificial intelligence techniques with optimised parameters. The methodology used for parameter setting can be applied to other metaheuristics for solving complex problems in practice. The performances of both algorithms are assessed using well-known test problems and it is observed that both algorithms find promising solutions. Artificial bee colony algorithm outperforms tabu search in minimising the number of workstations while tabu search shows a better performance in minimising the value of lexicographic bottleneck objective function.

International Journal of Disaster Risk Reduction, 2019

Computers & Industrial Engineering, 2017

Expert Systems with Applications, 2016

Journal of Intelligent Manufacturing, 2015

International Journal of Disaster Risk Reduction, 2020

Cellular Manufacturing Systems: Recent Developments, Analysis and Case Studies, 2017

International Journal of Production Research, 2011

Typically, the total number of required workstations are minimised for a given cycle time (this p... more Typically, the total number of required workstations are minimised for a given cycle time (this problem is referred to as type-1), or cycle time is minimised for a given number of workstations (this problem is referred to as type-2) in traditional balancing of assembly lines. However, variation in workload distributions of workstations is an important indicator of the quality of the obtained line balance. This needs to be taken into account to improve the reliability of an assembly line against unforeseeable circumstances, such as breakdowns or other failures. For this aim, a new problem, called lexicographic bottleneck mixed-model assembly line balancing problem (LB-MALBP), is presented and formalised. The lexicographic bottleneck objective, which was recently proposed for the simple single-model assembly line system in the literature, is considered for a mixed-model assembly line system. The mathematical model of the LB-MALBP is developed for the first time in the literature and coded in GAMS solver, and optimal solutions are presented for some small scale test problems available in the literature. As it is not possible to get optimal solutions for the large-scale instances, an artificial bee colony algorithm is also implemented for the solution of the LB-MALBP. The solution procedures of the algorithm are explored illustratively. The performance of the algorithm is also assessed using derived well-known test problems in this domain and promising results are observed in reasonable CPU times.

The main purpose of this study is the allocation of buffer stock tanks to different products, for... more The main purpose of this study is the allocation of buffer stock tanks to different products, for the production facilities operating in process type production systems of the fast-moving consumer goods (FMCG) industry. The important aspect of the FMCG sector is that the product variation is high, but the demand for each product type is low. A weekly production plan is constructed which must be satisfied on time with minimum amount of buffer stock. In contrast to the past buffer allocation studies, in process industry, there is a constraint that the liquid products cannot be mixed, unless they are of the same type, within the buffer tanks. Due to the random machine breakdowns, machine repair times, and complex production system structure, simulation is a very useful technique for this problem. A simulation model that measures several criteria reflecting the system performance is designed. After creating this model it is intended to determine the best scenario. Analytic Network Process method has been used as multi criteria decision making method, to evaluate the correlation among the performance criteria, compute the weights of the criteria, and select the best scenario. The proposed methodology has been tested by using a real FMCG factory data.