scholarly journals Cell Formation Based on New Similarity Coefficient with Operation Sequence and Alternative Routing

2019 ◽  
Vol 9 (1) ◽  
pp. 4065-4072
Keyword(s):  
Cell Formation ◽  
Similarity Coefficient ◽  
Test Problems ◽  
Specific Sequence ◽  
Forward Flow ◽  
Part Families ◽  
Operation Sequence ◽  
Production Factors ◽  
Alternative Process Routings ◽  
Alternative Routing

Cell formation is to construct machine cells and part families and then dispatch the part families to machine cells. Various cell formation approaches and algorithms have been developed over the years considering various production factors, scenarios and objectives. The results of these different approaches are evaluated based on the several parameters. Most of the studies have considered only either the operation sequence or the alternative routing. Very few of the approaches have proposed for considering both the operation sequence and the alternative routing. Here, a new method for the formation of cell and intracellular machine arrangement which is formulated by considering both the operation sequence and alternative process routings is proposed. The arrangement of machines and parts within the cell follows a specific sequence which is formed with the help of coefficient of similarity. Various parameters such as forward flow, backflow and voids in the cell formation scenarios are considered to evaluate the approach. With the help of these parameters problems from other literatures, which were solved by other methods are evaluated. So as to validate the effectiveness of our proposed approach, five eminent test problems from the previous literature are engaged and the results are compared with the existing method the results clearly display that the proposed approach which that provides superior or equal solution than the existing method.

scholarly journals Cell Formation Based on New Similarity Coefficient with Operation Sequence and Alternative Routing

2019 ◽  
Vol 9 (1) ◽  
pp. 4065-4072
Keyword(s):  
Cell Formation ◽  
Similarity Coefficient ◽  
Test Problems ◽  
Specific Sequence ◽  
Forward Flow ◽  
Part Families ◽  
Operation Sequence ◽  
Production Factors ◽  
Alternative Process Routings ◽  
Alternative Routing

Cell formation is to construct machine cells and part families and then dispatch the part families to machine cells. Various cell formation approaches and algorithms have been developed over the years considering various production factors, scenarios and objectives. The results of these different approaches are evaluated based on the several parameters. Most of the studies have considered only either the operation sequence or the alternative routing. Very few of the approaches have proposed for considering both the operation sequence and the alternative routing. Here, a new method for the formation of cell and intracellular machine arrangement which is formulated by considering both the operation sequence and alternative process routings is proposed. The arrangement of machines and parts within the cell follows a specific sequence which is formed with the help of coefficient of similarity. Various parameters such as forward flow, backflow and voids in the cell formation scenarios are considered to evaluate the approach. With the help of these parameters problems from other literatures, which were solved by other methods are evaluated. So as to validate the effectiveness of our proposed approach, five eminent test problems from the previous literature are engaged and the results are compared with the existing method the results clearly display that the proposed approach which that provides superior or equal solution than the existing method.

scholarly journals Simultaneous Hierarchical Clustering for Cell Formation Problems with Production Information

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Yingyu Zhu ◽  
Simon Li
Keyword(s):  
Hierarchical Clustering ◽  
Cell Formation ◽  
Similarity Coefficient ◽  
Similarity Coefficients ◽  
Multiple Production ◽  
Part Families ◽  
Production Factors ◽  
Machine Groups ◽  
Coefficient Method

The purpose of this paper is to advance the similarity coefficient method to solve cell formation (CF) problems in two aspects. Firstly, while numerous similarity coefficients have been proposed to incorporate different production factors in literature, a weighted sum formulation is applied to aggregate them into a nonbinary matrix to indicate the dependency strength among machines and parts. This practice allows flexible incorporation of multiple production factors in the resolution of CF problems. Secondly, a two-mode similarity coefficient is applied to simultaneously form machine groups and part families based on the classical framework of hierarchical clustering. This practice not only eliminates the sequential process of grouping machines (or parts) first and then assigning parts (or machines), but also improves the quality of solutions. The proposed clustering method has been tested through twelve literature examples. The results demonstrate that the proposed method can at least yield solutions comparable to the solutions obtained by metaheuristics. It can yield better results in some instances, as well.

Differentiation and positioning of nuclei in eggs of the cecidomyid Heteropeza pygmaea

1976 ◽  
Vol 22 (1) ◽  
pp. 99-113
Author(s):  
M. Meats ◽  
J.B. Tucker
Keyword(s):  
Structural Changes ◽  
Early Stage ◽  
Cell Formation ◽  
Longitudinal Axis ◽  
Posterior Pole ◽  
Spindle Orientation ◽  
Specific Sequence ◽  
Pole Cell ◽  
Polar Granules ◽  
Egg Chamber

During the first three cleavage divisions of the egg nuclei a precise sequence of spindle orientation and elongation parallel to the longitudinal axis of the egg is apparently involved in positioning one nucleus among the polar granules at the posterior pole of the egg. The size of this nucleus, and the position at which the egg cleaves when pole cell formation occurs, appear to constitute part of the mechanism which ensures that only one nucleus is included in the first pole cell. Blastoderm formation occurs without a well-defined migration of nuclei to the egg surface. Nuclei are so large in relation to the size of the egg that uniform spacing and distribution of nuclei ensures that a large proportion are situated near the egg surface. Those nuclei which are near the egg surface divide synchronously to form a layer of blastoderm nuclei, while membranous cleavage furrows invaginate from the egg surface between them. Nuclei in the central region of the egg chamber condense to form yolk nuclei before blastoderm nuclei have been separated from the rest of the egg by the completion of the cleavage membranes. Polar granules provide the only evidence of fine-structural differences in different regions of the egg chamber cytoplasm. They are found near the posterior pole of the egg from an early stage of oogenesis. They undergo a specific sequence of structural changes and increase in size as the egg grows. No microtubular or microfibrillar arrays have been found in the egg chamber which might form a cytoskeletal basis for spindle orientation or for the spatial differences which develop during differentiation of the uncleaved egg cytoplasm.

scholarly journals Modeling the Scheduling Problem in Cellular Manufacturing Systems Using Genetic Algorithm as an Efficient Meta-Heuristic Approach

2021 ◽  
Author(s):  
Amin Rezaeipanah ◽  
Musa Mojarad
Keyword(s):  
Genetic Algorithm ◽  
Manufacturing Systems ◽  
Cellular Manufacturing ◽  
Programming Model ◽  
Heuristic Method ◽  
Cell Formation ◽  
Mixed Integer ◽  
Test Problems ◽  
Cellular Manufacturing Systems ◽  
Machine Grouping

This paper presents a new, bi-criteria mixed-integer programming model for scheduling cells and pieces within each cell in a manufacturing cellular system. The objective of this model is to minimize the makespan and inter-cell movements simultaneously, while considering sequence-dependent cell setup times. In the CMS design and planning, three main steps must be considered, namely cell formation (i.e., piece families and machine grouping), inter and intra-cell layouts, and scheduling issue. Due to the fact that the Cellular Manufacturing Systems (CMS) problem is NP-Hard, a Genetic Algorithm (GA) as an efficient meta-heuristic method is proposed to solve such a hard problem. Finally, a number of test problems are solved to show the efficiency of the proposed GA and the related computational results are compared with the results obtained by the use of an optimization tool.

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