scholarly journals PRINCIPAL COMPONENT ANALYSIS AND SELF-ORGANIZING MAP FOR VISUAL CLUSTERING OF MACHINE-PART CELL FORMATION IN CELLULAR MANUFACTURING SYSTEM

2011 ◽  
Vol 05 (01) ◽  
pp. 25-51 ◽  
Author(s):  
MANOJIT CHATTOPADHYAY ◽  
PRANAB K. DAN ◽  
SITANATH MAZUMDAR
2012 ◽  
Vol 2 (4) ◽  
pp. 1175-1188 ◽  
Author(s):  
Manojit Chattopadhyaya ◽  
Sitanath Mazumdar ◽  
Pranab K Dan ◽  
Partha Sarathi Chakraborty

2016 ◽  
Vol 713 ◽  
pp. 107-110 ◽  
Author(s):  
Jhonatan Camacho-Navarro ◽  
Magda Ruiz ◽  
Rodolfo Villamizar ◽  
Luis Mujica ◽  
Oscar Pérez

Pipe leaks detection has a great economic, environmental and safety impact. Although several methods have been developed to solve the leak detection problem, some drawbacks such as continuous monitoring and robustness should be addressed yet. Thus, this paper presents the main results of using a leaks detection and classification methodology, which takes advantage of piezodiagnostics principle. It consists of: i) transmitting/sensing guided waves along the pipe surface by means of piezoelectric device ii) representing statistically the cross-correlated piezoelectric measurements by using Principal Component Analysis iii) identifying leaks by using error indexes computed from a statistical baseline model and iv) verifying the performance of the methodology by using a Self-Organizing Map as visualization tool and considering different leak scenario. In this sense, the methodology was experimentally evaluated in a carbon-steel pipe loop under different leaks scenarios, with several sizes and locations. In addition, the sensitivity of the methodology to temperature, humidity and pressure variations was experimentally validated. Therefore, the effectiveness of the methodology to detect and classify pipe leaks, under varying environmental and operational conditions, was demonstrated. As a result, the combination of piezodiagnostics approach, cross-correlation analysis, principal component analysis, and Self-Organizing Maps, become as promising solution in the field of structural health monitoring and specifically to achieve robust solution for pipe leak detection.


Author(s):  
Amit Bhandwale ◽  
Thenkurussi Kesavadas

The identification of part families and machine groups that form the cells is a major step in the development of a cellular manufacturing system. The primary input to cell formation algorithms is the machine-part incidence matrix, which is a binary matrix representing machining requirements of parts in various part families. One common assumption of these cell formation algorithms is that the product mix remains stable over a period of time. In today’s world, the market demand is being shaped by consumers, resulting in a highly volatile market. This has given rise to a class of products characterized by low volume and high variety, which presents engineers with lots of problems and decisions in the early stages of product development. This can have an adverse effect on manufacturing like high investment in new machinery and material handling equipment, long setup times, high tooling costs, increased intercellular movement and excessive scrap which increases the cost without adding any value to the parts. Any change to the product mix results in a change in the machine-part incidence matrix, which may change the part families and machine groups, which form the cells. The manufacturing system needs to be flexible in order to handle large product mix changes. This paper discusses the impact of product mix variations on cellular manufacturing and presents a methodology to incorporate these variations into an existing cellular manufacturing setup.


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