Search results

The purpose of this paper is to develop a mathematical model for the design of robust layout for unequal area-dynamic facility layout problem with flexible bay structure (UA-DFLP with FBS) and test the suitability of generated robust layout in a dynamic environment.

This research adopts formulation of a mathematical model for generating a single layout for unequal area facility layout problems with flexible bay structure under dynamic environment. The formulated model for the robust layout formation is solved by developing a simulated annealing algorithm. The proposed robust approach model for UA-DFLP with FBS is validated by conducting numerical experiments on standard UA-DFLPs reported in the literature. The suitability of the generated robust layout in a dynamic environment is tested with total penalty cost criteria.

The proposed model has given a better solution for some UA-DFLPs with FBS in comparison with the adaptive approach’s solution reported in the literature. The total penalty cost is within the specified limit given in the literature, for most of the layouts generated for UA-DFLPs with FBS. In the proposed model, there is no rearrangement of facilities in various periods of planning horizon and thus no disruptions in operations.

The present work has limitations that when the area and aspect ratio of the facilities are required to change from one period to another, then it is not possible to make application of the robust approach-based formulation to the dynamic environment facility layout problems.

Rearrangement of facilities in adaptive approach disrupts the operations whereas in the proposed approach no disruption of production. The FBS approach is more suitable for layout planning where proper aisle structure is required. The solution of the proposed approach helps to create a proper aisle structure in the detailed layout plan. Thus, easy interaction of the material handling equipment, men and materials is possible.

This paper proposes a mathematical formulation for the design of robust layout for UA-FLPs with FBS in a dynamic environment and an efficient simulated annealing algorithm as its solution procedure. The proposed robust approach generates a single layout for the entire planning horizon. This approach is more useful for facilities which are difficult/sensitive to relocate in various periods of the planning horizon.

The purpose of this paper is to review, evaluate and classify the academic research that has been published in facility layout problems (FLPs) and to analyse how researches and practices on FLPs are.

The review is based on 166 papers published from 1953 to 2021 in international peer-reviewed journals. The literature review on FLPs is presented under broader headings of discrete space and continuous space FLPs. The important formulations of FLPs under static and dynamic environments represented in the discrete and continuous space are presented. The articles reported in the literature on various representations of facilities for the continuous space Unequal Area Facility Layout Problems (UA-FLPs) are summarized. Discussed and commented on adaptive and robust approaches for dynamic environment FLPs. Highlighted the application of meta-heuristic solution methods for FLPs of a larger size.

It is found that most of the earlier research adopted the discrete space for the formulation of FLPs. This type of space representation for FLPs mostly assumes an equal area for all facilities. UA-FLPs represented in discrete space yield irregular shape facilities. It is also observed that the recent works consider the UA-FLPs in continuous space. The solution of continuous space UA-FLPs is more accurate and realistic. Some of the recent works on UA-FLPs consider the flexible bay structure (FBS) due to its advantages over the other representations. FBS helps the proper design of aisle structure in the detailed layout plan. Further, the recent articles reported in the literature consider the dynamic environment for both equal and unequal area FLPs to cope with the changing market environment. It is also found that FLPs are Non-deterministic Polynomial-complete problems, and hence, they set the challenges to researchers to develop efficient meta-heuristic methods to solve the bigger size FLPs in a reasonable time.

Due to the extremely large number of papers on FLPs, a few papers may have inadvertently been missed. The facility layout design research domain is extremely vast which covers other areas such as cellular layouts, pick and drop points and aisle structure design. This research review on FLPs did not consider the papers published on cellular layouts, pick and drop points and aisle structure design. Despite the possibility of not being all-inclusive, the authors firmly believe that most of the papers published on FLPs are covered and the general picture presented on various approaches and parameters of FLPs in this paper are precise and trustworthy.

To the best of the authors’ knowledge, this paper reviews and classifies the literature on FLPs for the first time under the broader headings of discrete space and continuous space representations. Many important formulations of FLPs under static and dynamic environments represented in the discrete and continuous space are presented. This paper also provides the observations from the literature review and identifies the prospective future directions.

As far as the authors know, no research has already been carried out on the multi-floor dynamic facility layout problem (MF-DFLP) in the continuous form regarding the flexible bay structure, the number and the variable location of the elevator. Therefore, the present paper models the given problem and attempts to find a sub-optimal solution for it using a meta-heuristic simulated annealing (SA) algorithm.

The efficient use of resources has always been a prominent matter for decision-makers. Many reasons including land use, construction considerations and proximity of departments have led to the design of multi-floor facilities. On the other hand, their fast-evolving environment calls for dynamic planning. Therefore, in this paper, a model and the SA algorithm for MF-DFLP are presented.

After presenting a mathematical model, the problem was solved precisely in a small size using the GAMS software. Also, a near-optimal solution method using a SA meta-heuristic algorithm is suggested and the proposed algorithm was run in the MATLAB software. To evaluate the presented model and the proposed solution, some test cases were considered in two aspects. The first aspect was the test cases that are newly generated in small, medium and large sizes to compare the exact optimal solution with the results of the meta-heuristic algorithm. Eight test cases with small sizes were solved using the GAMS software, the optimum solutions were obtained in a reasonable time, and the cost of their solutions was equal to that of the SA algorithm. Eight test cases with medium sizes were run in the GAMS software with the time limit of 80,000 s, and the SA algorithm had performed better for these test cases. Two test cases were also considered in large size that GAMS could not solve them, whereas the SA algorithm successfully found a proper solution for each. The second aspect included the test cases from the literature. The result showed that suggested algorithm is more capable of finding best solutions than compared algorithms.

In this paper, an unequal area MF-DFLP was studied in a continuous layout form in which the location and number of the elevators were considered to be variable, and the layouts were considered with flexible bay structure. These conditions were investigated for the first time.

The home page design of a digital news website is a key factor in determining its attractiveness to readers. This study aims to propose an approach to manage the frequent adjustment of the dynamic layout of the news content on the website home page in a real-time environment to increase its attractiveness to readers.

This paper shows that this news website layout design problem can be modeled as an optimization problem based on the information of news contents that change within a multiple-period planning horizon similar to the dynamic facility layout problem. A hybrid genetic algorithm-based approach integrated with local search heuristic methods is also proposed to improve the solution.

This paper finds that the DPLP model is effective in modeling the changing layout of a digital news website. The problem can solved in a timely manner using the proposed hybrid genetic algorithm.

This paper was based on hypothetical data and on the assumption of equal section size. Actual data would help fine-tune the application of the dynamic facility layout model. As well the algorithm could be enhanced for unequal size sections.

The model should help online newspapers apply sophisticated algorithms to optimize the layout of news websites dynamically in a timely manner.

News websites are increasingly the desired medium to consume news. So it has an important role in educating society. Thus optimizing and improving the process will help in this regard.

To the best of the authors’ knowledge, this paper is the first one to apply the DPLP model to the digital newspaper website dynamic design problem.

This paper develops a platform that can be used to determine how to effectively and efficiently deal with a large number of temporary facilities under a constrained site condition(s). The ultimate goal is to reduce the material handling costs between transformation phases of construction works occurring during the project's development period.

Empirical and deductive research is first adopted to mathematical model dynamic site layout planning using the branch and bond algorithm (B&B). Second, a real-life construction project is examined to illustrate how dynamic site layout planning (using the aforementioned B&B algorithm and a computer software program called LINGO) can reduce the material handling costs. The application of the proposed methodology is then showcased against a case study that utilizes a comparative analysis between the “dynamic” and “statistic” site planning approaches.

By dividing the construction period into different phases, the developed model is shown to be capable of optimizing the material handling costs between the phases of transformation during construction works. Optimal costs are also considered using the site boundary and unit cost for moving construction materials between two facilities. The comparative analysis results illustrate that the B&B algorithm reduces material handling costs by 33%.

The proposed model offers an effective planning algorithm for the site layout and location of temporary facilities. More specifically, it can make a substantial improvement in reducing the travel time and material handling cost between the temporary facilities in the construction sites.

The primary knowledge contribution of this study to the site layout is successfully deal with the unequal area problem of temporary site facilities and incorporates the concept of dynamics site planning into the algorithm.

A layout problem may deal with the assignment and arrangement of buildings in a green field, location and/or relocation of machines/departments in manufacturing facilities, and so on. If multi‐periods are considered, the problem is called a dynamic layout problem in manufacturing environments. Designing web pages, especially internet newspaper layouts, might also be considered dynamic layout problems. This study aims to introduce a layout procedure for the front page of internet newspapers.

The news contents are ranked and selected based on their characteristic attributes. Then they are assigned to locations on dynamic content area of the front page. Layout optimization is made by use of Clonal Selection Algorithm (CSA). Finally, an illustrative example is provided and concepts for real life applications are discussed. The proposed method is based on CSA, which is a nature‐inspired technique. The novel heuristic is applied to a simulated system to depict how the news content layouts can be optimized in dynamic environments.

The capacity for addition of new news contents and removal of the old turns the internet newspaper environment into a dynamic structure. A systematic layout method for internet newspapers is developed to fill the gap.

The results are encouraging for real life applications of internet newspapers. The study has also introduced a new site for the manufacturing area. In the classic dynamic layout model, the machine locations and the number of available machines are assumed to be fixed. But the concept of introducing/removing news contents can be adapted to the machines at the manufacturing facilities.

The paper's value lies in showing that the front page layout is not considered to optimize the locations of the articles. Also, the proposed algorithm is applied to solve these kinds of problems.

The purpose of this article is to develop a bi-directional relaxed flexible bay structure (BRFBS) in the layout for the unequal area facility layout problems (UA-FLPs) and test the suitability of the proposed approach using literature data.

This research adopts a two-stage solution approach for UA-FLPs to form BRFBS in the layout. The solution to UA-FLPs is carried out in discrete space. The proposed heuristic method optimises the layout plan for minimising the material handling cost (MHC), and also, it indirectly optimises the space utilisation by reducing the empty space in the layout. The first stage of layout design assumes that all facilities are equal in size and uses quadratic assignment problem (QAP) model. QAP is solved with a simulated annealing heuristic method. In the second stage, a heuristic method is proposed to find the optimum width for each bay and the dimension for facilities. The proposed heuristic method is tested with numerical data available in the literature. Results are compared with the results obtained by layout planning software, and with the simulated annealing algorithm for flexible bay structure (SA-FBS) heuristic procedure for continuous space UA-FLPs.

The proposed two-stage solution approach gives the BRFBS for the UA-FLPs. BRFBS helps to create proper aisle structure in the layout plan. The layout configuration and solution of the proposed method is better than the layout planning software solution and SA-FBS solution. The application of the proposed heuristic method to case data gave lesser MHC, better space utilisation and better aisle formation than the existing layout.

The proposed approach has the limitation that it can be applied only to UA-FLPs solved in discrete space. When the UA-FLPs are solved in continuous space, then it is not possible to make application of this approach to form bi-directional relaxed flexible bays in the layout plan.

Most of the modern industries are automated, and they use material handling equipment (MHE) like automated guided vehicles (AGVs). Design of layout plans that help to create proper aisle structure for AGV’s in the layout plan is a challenging to the researchers. The BRFBS configuration is more suitable in the flexible manufacturing system where AGVs are used for material transportation.

This paper proposes a novel two-stage heuristic method for solving the UA-FLPs in discrete space. The proposed approach generates a BRFBS in the layout plan. The BRFBS helps to create a proper aisle structure suitable for better material handling operations. Hence, this type of layout helps in easy interaction of the MHE (e.g. AGVs) with the boundaries of the facilities touching the aisle.

In today’s competitive market, product demand and its mix frequently vary due to various uncertainties, which thus imparts the overall manufacturing cost. Furthermore, uncertainties also impart the layout design in manufacturing industries in the long run. Therefore, the layout design needs to capture the possibility of uncertainties, and these uncertainties must be captured while designing the layout of a facility. Hence, an efficient facility layout design minimizes the manufacturing cost and lead time. The purpose of this paper is to propose a cellular layout design for a tower manufacturing industry.

The paper develops an embedded simulated annealing-based meta-heuristic to solve proposed cellular layout under different scenarios considering single and multi-time periods for tower manufacturing industry. A comparative study is also performed to analyze comparison among static cellular layout, a dynamic cellular layout or a robust stochastic cellular layout for the tower manufacturing industry.

The current layout of the industry is a process layout. Here, the layout for a tower manufacturing industry is proposed under SCFLP, DCFLP and RSCFLP. The proposed models and solution methodology is tested using six scenarios with different combination of time periods. Lastly, OFV value obtained for all the scenarios is compared, and it is found that RSCFLP outruns other SCFLP and DCFLP for a tower manufacturing industry. Based on the above study, it is also concluded that RSCFLP is an efficient and effective layout in tower manufacturing industry.

The paper proposes a cellular layout design for a tower manufacturing industry. The cellular layout design is found to be preferred over the traditional layout as it reduces material handling cost, manufacturing lead time and hazards. Moreover, it enhances productivity and quality.

The facility layout problem aims to assign machines/departments to locations and modeled as a quadratic assignment problem (QAP). Multi period facility layout is a special case of this problem where the sum of material handling and re‐layout costs are minimized. Since the problem is proved to be NP‐hard, several exact and heuristic methods are proposed in the literature. The purpose of this paper is to solve the multi period layout problem by using the modified sub‐gradient (MSG) algorithm for the first time and to determine its parameters.

The MSG algorithm can solve a large‐scale of optimization problems that also includes multi period facility layout. Since the performance of the algorithm depends on parameters, a design of experiment is made to determine the appropriate parameter values.

The proposed method evaluates the parameters of the MSG algorithm and most suitable general algebraic modeling solvers. It is observed that the parameter α value and solver type have main effects for small and large size test problems. Further, the results stated that solver type has more influence on large size test problem.

This study is limited with the determination of the MSG algorithm parameters and solver types on the well known small and large size test problems. Further studies may include other test problem results obtained from the presented MSG algorithm parameters and compare them with best known results in the literature.

The paper determines the parameters of the MSG algorithm that is used to solve the multi period layout problem, for the first time in the literature.

The purpose of this paper is to analyse the use of a product‐oriented layout and a work‐cell strategy in order to maximise efficiency. These two categories of layout strategies are discussed separately, and are then used collectively in an analysis of the company. The aim is to understand how improvements on layout design could positively impact the future efficiency of the case study company.

A model was developed and measured using 26 weeks of data between the fourth quarter of 2009 and the first quarter of 2010 during layout transformations at the case study company based in upstate New York. The model compared variables such as the distance traveled to retrieve parts, average daily output of engines, labour cost per unit produced, and the amount of time the engine remains in each cell; the aim of which is to increase the efficiency of the facility.

The findings indicate that there is a strong correlation between the variables improved at both the cell‐structures and the product‐structures of the facility and the overall efficiency of the manufacturing facility itself. The results also show that an overall higher efficiency allows for the facility to handle much larger workloads and also drives down both short‐run and long‐run costs. The outcomes also allow for a suggestive redesign of the facility in order to further maximise efficiency. However, it was found that the amount of time a product remains in each cell on the assembly line does not have an effect on the overall output of diesel engines.

Various studies have been conducted focusing on the “facility layout problem,” yet thorough analyses of the redesigning of layout in regards to efficiency are not as available. Instead, an understanding of the topic was derived through sources focusing on the specificities of manufacturing layout.

This paper describes layout efficiency through redesigns and layout using work‐cells in a product‐oriented environment. This study would be useful to manufacturers having low variability in their product and having the ability to use work‐cell layout within their facility.