Ivana Ljubić

Obtaining optimal k-cardinality trees fast (2008)

Markus Chimani, Maria K, Ivana Ljubić, Petra Mutzel

Abstract. Given an undirected graph G = (V, E) with edge weights and a positive integer number k, the k-Cardinality Tree problem is to find a subtree T of G with exactly k edges and the minimum...

Strong Formulations for 2-Node-Connected Steiner Network Problems (TR) (2007)

Markus Chimani, Maria K, Ivana Ljubić, Petra Mutzel

Abstract. We consider a survivable network design problem known as the 2-Node-Connected Steiner Network Problem (2NCON): we are given a weighted undirected graph with a node partition into two sets...

Solving the prize-collecting Steiner tree problem to optimality (2005)

Ivana Ljubić, René Weiskircher, Ulrich Pferschy, Gunnar Klau, Petra Mutzel

The Prize-Collecting Steiner Tree Problem (PCST) on a graph with edge costs and vertex profits asks for a subtree minimizing the sum of the total cost of all edges in the subtree plus the total...

Solving the Prize-Collecting Steiner Tree Problem (2004)

Ivana Lubic, Ivana Ljubić, René Weiskircher, René Weiskircher, Ulrich Pferschy, Ulrich Pferschy, ...

The Prize-Collecting Steiner Tree Problem (PCST) on a graph with edge costs and vertex profits asks for a subtree minimizing the sum of the total cost of all edges in the subtree plus the total...

A Genetic Algorithm for the Index Selection Problem (2003)

Jozef Kratica, Ivana Ljubić

Abstract. This paper considers the problem of minimizing the response time for a given database workload by a proper choice of indexes. This problem is NP-hard and known in the literature as the...

The fractional prize-collecting Steiner tree problem on trees (2003)

Gunnar W. Klau, Gunnar W. Klau, Ivana Ljubić, Ivana Ljubić, Petra Mutzel, Petra Mutzel, ...

Abstract. We consider the fractional prize-collecting Steiner tree problem on trees. This problem asks for a subtree T containing the root of a given tree G = (V, E) maximizing the ratio of the...

A memetic algorithm for minimum-cost vertex-biconnectivity augmentation of graphs (2003)

I. Ljubić, G. R. Raidl, Ivana Ljubić, Günther R. Raidl, Contact Günther Raidl

This paper considers the problem of augmenting a given graph by a cheapest possible set of addi-tional edges in order to make the graph vertex-biconnected. A real-world instance of this problem is...

A memetic algorithm for vertex-biconnectivity augmentation (2002)

Or Kersting, Günther R. Raidl, Ivana Ljubić

Abstract. This paper considers the problem of augmenting a given graph by a cheapest possible set of additional edges in order to make the graph vertex-biconnected. A real-world instance of this...

Solving the simple plant location problem by genetic algorithm (2001)

Jozef Kratica, Vladimir Filipović, Ivana Ljubić, Communicated P. Tolla

Abstract. The simple plant location problem (SPLP) is considered and a genetic algorithm is proposed to solve this problem. By using the developed algorithm it is possible to solve SPLP with more...

An evolutionary algorithm with stochastic hill-climbing for the edge-biconnectivity augmentation problem (2001)

Ivana Ljubić, Günther R. Raidl

Abstract. Augmenting an existing network with additional links to achieve higher robustness and survivability plays an important role in network design. We consider the problem of augmenting a...

A hybrid GA for the edge-biconnectivity augmentation problem (2000)

Ivana Ljubić, Günther R. Raidl, Jozef Kratica

Abstract. In the design of communication networks, robustness against failures in single links or nodes is an important issue. This paper proposes a new approach for the N P-complete...