165,095 research outputs found
Two-stage approach for nesting in two-dimensional cutting problems using neural network and simulated annealing
No full textNesting of two-dimensional patterns on a given raw sheet has applications in a number of industries. It is a common problem often faced by designers in the shipbuilding, garment making, blanking die design, glass and wood industries. This paper presents a new two-stage layout approach for nesting two-dimensional patterns by using the self-organization assisted layout and simulated annealing. The proposed nesting approach consists of two stages: initial layout stage and layout improvement stage. This heuristic algorithm generates a 'good' initial layout by using the self-organization assisted layout (SOAL) algorithm and then improves the layout by using the simulated annealing (SA) algorithm. Some examples are treated for showing the effectiveness of this approach in nesting the two-dimensional irregular patterns with and without holes
A study on torch path planning in laser cutting processes - Part 1: Calculation of heat flow in contour laser beam cutting
No full textConductive heat transfer in contour laser beam cutting is analyzed by using a transient, two-dimensional finite difference model, and the result is combined with a simple analytic model. From the calculation results, the correlation is derived between workpiece temperature and opening angles at a corner in contour cutting. As a result, a modified analytic solution is developed to predict if excessive workpiece heating occurs for given cutting contours in a nested plate. The main objective is to use the computation results in the optimization of torch path planning to provide fully automated CNC programming software for laser cutting. To efficiently apply the analytic model in torch path planning, the critical temperature that should be avoided during the cutting sequence is considered. This leads to an improvement of the cutting quality in the automatic cutting process
Global torch path generation for 2-D laser cutting process using simulated annealing
No full textRecently the major objective of laser processing in production line is the precision or shape cutting of sheet metals. This paper addresses the problem of a torch path generation for the 2D laser cutting of a stock plate nested with irregular parts. In this paper, the basic object is a polygon(a many-sided figure) with holes. Under the constraint of the relative positions of parts enforced by nesting, the developed torch path algorithm generates feasible cutting paths. The objective of this work is to traverse this cutting contours with a minimum path length. The proposed torch path algorithm is based on a simulated annealing, that is an improved version of previously suggested TSP models. Since every piercing point of parts is not fixed in advance, the algorithm solves an relaxed optimization problem with constraints. For solving the torch path optimization problem an efficient generation mechanism of neighborhood structure and annealing schedule were presented. In this way, a global solution can be obtained in a reasonable time. Several examples are represented to illustrate the method
A multi-stage solution for nesting in two-dimensional cutting problems using neural networks
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Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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