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Hyper-Heuristic Approach for Improving Marker Efficiency

Domović D., Rolich T., Golub M.

Autex Research Journal

2018

Vol. 18, no. 4

348--363

Marker planning is an optimization arrangement problem, where a set of cutting parts need to be placed on a thin paper without overlapping to create a marker – an exact diagram of cutting parts that will be cut from a single spread. An optimal marker that utilizes the length of textile material has to be obtained. The aim of this research was to develop novel algorithms for obtaining an efficient marker that would achieve competitive results and optimize the garment production in terms of improving the utilization of textile material. In this research, a novel Grid heuristic was introduced for obtaining a marker, alongside its improvement methods: Grid-BLP and Grid-Shaking. These heuristics were hybridized with genetic algorithm that determined the placement order of cutting parts using the newly introduced All Equal First (AEF) placement order. A novel individual representation for genetic algorithm was designed that was composed of order sequence, rotation detection and the choice of placement algorithm (hyper-heuristic). Experiments were conducted to determine the best marker making method, and hyper-heuristic efficiency. The implementation and experiments were conducted in MATLAB using GEATbx toolbox on five datasets from the garment industry: ALBANO, DAGLI, MAO, MARQUES and MAN SHIRT. Marker efficiency in percentage was recorded with best results: 84.50%, 80.13%, 79.54%, 84.67% and 86.02% obtained for the datasets respectively. The most efficient heuristic was Grid-Shaking. Hyper-heuristic applied Grid-Shaking in 88% of times. The created algorithm is independent of cutting parts’ shape. It can produce markers of arbitrary shape and is flexible in terms of expansion to new instances from the garment industry (leather nesting, avoiding damaged areas of material, marker making with materials with patterns).

Hiperheurystyki w kolorowaniu grafów

Dąbrowski J., Obszarski P.

Zeszyty Naukowe Wydziału ETI Politechniki Gdańskiej. Technologie Informacyjne

2007

T. 13

443-448

Hiperheurystyki to jeden z nowych trendów w technice obliczeniowej. Można je zdefiniować jako algorytmy, które wykorzystują zdefiniowany zbiór prostych heurystyk do znalezienia przybliżonego rozwiązania. Celem algorytmu jest znalezienie takiej sekwencji uruchamiania tych prostych operacji, która będzie dawała najlepsze rozwiązanie dla danej instancji problemu lub danej klasy instancji problemu. W pracy zdefiniowano heurystyki dla problemu wierzchołkowego kolorowania grafów oraz przedstawiono algorytm genetyczny, w którym ewolucji podlegają sekwencje ich wyboru przy kolorowaniu zachłannym.

Hyperheuristics are optimization algorithms that use sets of simple heuristic operations that can change the state of a solution. The goal of the algorithm is to find a good sequence of those operations that produces a good solution to the problem. This work presents low-level heuristics for the well known Graph Coloring Problem and a genetic algorithm that evolves sequences of choices for a greedy coloring algorithm.