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## Journal of Combinatorial Optimization OnlineFirst articles

23-09-2021

### An ant colony optimization approach for the proportionate multiprocessor open shop

Multiprocessor open shop makes a generalization to classical open shop by allowing parallel machines for the same task. Scheduling of this shop environment to minimize the makespan is a strongly NP-Hard problem. Despite its wide application areas …

21-09-2021

### On the restricted k-Steiner tree problem

Given a set P of n points in $$\mathbb {R}^2$$ R 2 and an input line $$\gamma$$ γ in $$\mathbb {R}^2$$ R 2 , we present an algorithm that runs in optimal $$\varTheta (n\log n)$$ Θ ( n log n ) time and $$\varTheta (n)$$ Θ ( n ) space to solve a …

17-09-2021

### Metaheuristic algorithms for the bandwidth reduction of large-scale matrices

This paper considers the bandwidth reduction problem for large-scale sparse matrices in serial computations. A heuristic for bandwidth reduction reorders the rows and columns of a given sparse matrix. Thus, the method places entries with a nonzero …

15-09-2021

### Adjacent vertex distinguishing edge coloring of IC-planar graphs

The adjacent vertex distinguishing edge coloring of a graph G is a proper edge coloring in which each pair of adjacent vertices is assigned different color sets. The smallest number of colors for which G has such a coloring is denoted by \chi …

09-09-2021

Based on the momentum principle and adaptive learning mechanism, we design online portfolio selection strategies, which are suitable for nonstationary financial market. Firstly, we propose a Moving-window-based Adaptive Exponential Gradient (MAEG) …