Robust Optimization of Mixed-Integer Problems Using NURBs-Based Metamodels

Author(s):  
John C. Steuben ◽  
Cameron J. Turner

The optimization of mixed-integer problems is a classic problem with many industrial and design applications. A number of algorithms exist for the numerical optimization of these problems, but the robust optimization of mixed-integer problems has been explored to a far lesser extent. We present here a general methodology for the robust optimization of mixed-integer problems using nonuniform rational B-spline (NURBs) based metamodels and graph theory concepts. The use of these techniques allows for a new and powerful definition of robustness along integer variables. In this work, we define robustness as an invariance in problem structure, as opposed to insensitivity in the dependent variables. The application of this approach is demonstrated on two test problems. We conclude with a performance analysis of our new approach, comparisons to existing approaches, and our views on the future development of this technique.

Author(s):  
John C. Steuben ◽  
Cameron J. Turner

The optimization of mixed-integer problems is a classic problem with many industrial and design applications. A number of algorithms exist for the numerical optimization of these problems, but the robust optimization of mixed-integer problems has been explored to a far lesser extent. We present here a general methodology for the robust optimization of mixed-integer problems using Non Uniform Rational B-spline (NURBs)-based metamodels and graph theory concepts. The use of these techniques allows for a new and powerful definition of robustness along integer variables. In this work, we define robustness as an invariance in problem structure, as opposed to insensitivity in the dependent variables. The application of this approach is demonstrated on two test problems. We conclude with a performance analysis of our new approach, comparisons to existing approaches, and our views on the future development of this technique.


Author(s):  
John Steuben ◽  
Cameron J. Turner

NURBs-based metamodels have been shown to accurately reproduce the behavior of computationally expensive models. These models in turn represent engineering problems of great complexity and importance. While the structure of NURBs-based metamodels has facilitated the development of discrete optimization algorithms, other analysis areas such as robust and multiobjective optimization have proven to be more difficult. We present here a new method for the analysis and optimization of these metamodels which is based on graph theory principles. The adoption of these principles allows the use of powerful existing algorithms for graph analysis. We have focused on the problem of robust optimization in this work, as the robust optimization of NURBs-based metamodels has been previously examined using more conventional techniques. We demonstrate that the graph-based analysis technique provides the design engineer a more comprehensive understanding of design problems and their behavior. We also demonstrate the new technique on a range of test functions in order to establish its validity and usefulness in the context of product and process optimization. We conclude with a discussion of the use of this new approach in addressing other analysis challenges such as multiobjective or mixed-integer optimization.


2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Anandi Silva Knuppel

Scholarship on Hindu traditions and practices proposes the practice of darshan as fundamental to Hindu traditions, particularly in temple worship, observing that devotees seek out images of deities primarily to see them and “receive” their darshan. These works typically gloss the definition of darshan with a sentence or two about seeing, exchanging glances, and/or receiving blessings. In this paper, I focus on the ways in which darshan is ideally imagined in conjunction with other bodily sensory practices through sources of authority, such as texts and senior devotees, to create a specific sensory experience and expectation in the transnational Gaudiya Vaishnava community. I then look to the lived realitiesof darshan in this tradition, specifically how devotees negotiate the structures created through sources of authority in their daily lives. Through this juxtaposition of idealized and lived darshan, I argue that we need a new approach towards theories of practice to take into account the complexities of darshanic moments in this and other religious practices.


2016 ◽  
Vol 36 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Hamid Yilmaz ◽  
Mustafa Yilmaz

Purpose – Within team-oriented approaches, tasks are assigned to teams before being assigned to workstations as a reality of industry. So it becomes clear, which workers assemble which tasks. Design/methodology/approach – Team numbers of the assembly line can increase with the number of tasks, but at the same time, due to physical situations of the stations, there will be limitations of maximum working team numbers in a station. For this purpose, heuristic assembly line balancing (ALB) procedure is used and mathematical model is developed for the problem. Findings – Well-known assembly line test problems widely used in the literature are solved to indicate the effectiveness and applicability of the proposed approach in practice. Originality/value – This paper draws attention to ALB problem in which workers have been assigned to teams in advance due to the need for specialized skills or equipment on the line for the first time.


2020 ◽  
Vol 1 (1) ◽  
pp. 61-72
Author(s):  
Carlos Bardavío Antón

The field of cults, and that of destructive or coercive cults in particular, has received little attention from the perspective of criminal law doctrine. Supporters of such groups often claim to be victims of a violation related to freedom of will. In this article, I consider various methodologies and manipulation techniques used by such groups and suggest that comparative law, criminal definitions, and regulatory problems provide the basis for a more comprehensive understanding of criminal phenomenology that includes these concerns: the loss of freedom through coercive persuasion, and thus being the victim of a crime, or through becoming an instrument for the commission of crimes ordered by third parties. Research shows that the conventional definition of crime against freedom of will and physical injury is inadequate. I posit that a new approach to legal doctrine and criminal classification is required to fight against new crime phenomenology. I propose a criminal classification aimed at considering coercive persuasion as a crime, and a definition for the criminalization of certain organizations that engage in willful misconduct or reckless conduct.


Author(s):  
Iulia-Adina Lehene

This paper is the second part of a work that aims to rethink the concept of beauty as close as possible to its essence and in a way that integrates the science of aesthetics with the field of construction. Within other theoretical and practical works, this study may be further used to physically reflect the definition of beauty in areas such as architecture, civil engineering or urban planning and support professionals in designing and building beautiful objects and constructions. However, it has to be added that the assumption that there must be a particular original aspect related to beauty that leads a human-made object to success, needs to be further identified. The approach to the concept of beauty is through a general philosophical perspective and partially through the areas mentioned above.The second part of the study includes the synthesised guidance provided by Monroe Beardsley through the theories on beauty from the nineteenth century until today. In addition, it comprises the scheme of concepts that characterised the beautiful in this time, including the lines that guided its study, previous ideas that support our later views on presented theory, and a brief exposition of Maslow's theory of human motivation followed by our theory on beauty and the conclusions.


Author(s):  
Amin Rezaeipanah ◽  
Musa Mojarad

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.


Author(s):  
Hachemi Rachedi Lamia ◽  
Lakehal Moussa ◽  
Achour Bachir

Abstract The critical regime plays a primordial role in the study of gradually varying flows by classifying flow regimes and slopes. Through this work, a new approach is proposed to analyze critical flow regime in an egg-shaped channel. Based on both the definition of Froude number and Achour and Bedjaoui general discharge relationship, a relation between critical and normal depths is derived and then graphically represented for the particular case of a smooth channel characterized by a generating diameter equal to one meter. The results show the influence of the slope on the frequency of occurrence of the critical regime. At the same time and independently of the flow rate, a very advantageous approach for the calculation of the Froude number has been proposed. The study shows that there are six zones to differentiate the various flow states, namely: on the one hand for steep slopes two subcritical zones interspersed by a supercritical zone and on the other hand for mild slopes a zone corresponding to uniform flow, an area where the flow is probably gradually varied and finally an area where the flow is abruptly varied. Based on the specific energy equation, a validation process concluded that the proposed relationships were reliable.


Author(s):  
Andrea Conchado Peiró ◽  
José Miguel Carot Sierra ◽  
Elena Vázquez Barrachina ◽  
Enrique Orduña Malea

Cybermetrics field is attracting considerable interest due to its utility as a data-oriented technique for research, though it may provide misleading information when used in complex systems. This paper outlines a new approach to market research analysis through the definition of composite indicators for cybermetrics, applied to the Spanish wine market. Our findings show that the majority of cellars were present in only one or two social media networks: Facebook, Twitter or both. Besides, the presence on the Web can be summarized into three principal components: website quality, presence on Facebook, and presence on Twitter. Three groups of cellars were identified according to their position in these components: cellars with a high number of errors in their website with complete absence of information in social media, cellars with strong presence in social media, and cellars in an intermediate position. Our results constitute an excellent initial step towards the definition of a methodology for building composite indicators in cybermetrics. From a practical approach, these indicators may encourage cellar managers to make better decisions towards their transition to the digital market.


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