Adrian Deaconu | Transylvania University of Brasov (original) (raw)

Papers by Adrian Deaconu

A linear time and space algorithm for construction of a binary tree from the pre-order and post-o... more A linear time and space algorithm for construction of a binary tree from the pre-order and post-order traversals is presented. The solution is not always unique. The number of solutions is calculated and an optimal time and space method to find all the solutions is shown.

Rairo-operations Research, 2008

ABSTRACT The problem is to modify the capacities of the arcs from a network so that a given feasi... more ABSTRACT The problem is to modify the capacities of the arcs from a network so that a given feasible flow becomes a maximum flow and the maximum change of the capacities on arcs is minimum. A very fast O(mlog(n)) time complexity algorithm for solving this problem is presented, where m is the number of arcs and n is the number of nodes of the network. The case when both, lower and upper bounds of the flow can be modified so that the given feasible flow becomes a maximum flow is also discussed. The algorithm proposed can be adapted to solve this problem, too. The inverse minimum flow problem considering l ∞ norm is also studied.

Yugoslav Journal of Operations Research, 2008

The general inverse maximum flow problem (denoted GIMF) is considered, where lower and upper boun... more The general inverse maximum flow problem (denoted GIMF) is considered, where lower and upper bounds for the flow are changed so that a given feasible flow becomes a maximum flow and the distance (considering l 1 norm) between the initial vector of bounds and the modified vector is minimum. Strongly and weakly polynomial algorithms for solving this problem are proposed. In the paper it is also proved that the inverse maximum flow problem where only the upper bound for the flow is changed (IMF) is a particular case of the GIMF problem.

Scientific Annals of Cuza University, 2006

Journal of Applied Mathematics and Computing, 2007

In this paper we consider the inverse minimum flow (ImF) problem, where lower and upper bounds fo... more In this paper we consider the inverse minimum flow (ImF) problem, where lower and upper bounds for the flow must be changed as little as possible so that a given feasible flow becomes a minimum flow. A linear time and space method to decide if the problem has solution is presented. Strongly and weakly polynomial algorithms for solving the ImF problem are proposed. Some particular cases are studied and a numerical example is given.

The theory and applications of network flows is probabily the most important single tool for appl... more The theory and applications of network flows is probabily the most important single tool for applications of digraphs and perhaps even of graphs as a whole. In this paper we study minimum flow an algorithm in bipartite networks with unit capacities combining an algorithm for minimum flow in bipartite networks with an algorithm for minimum flow in unit capacity networks. Finally, we present the applications of the minimum flow problem in bipartite networks with unit capacities.

The Smart Grid of the future will be created starting from Smart Microgrids. The modeling of Micr... more The Smart Grid of the future will be created starting from Smart Microgrids. The modeling of Microgrids and the simulations of their real time steady state status is presented in the paper. The model is created using graphs. This paper continues a previous one, which dealt with the active power flow. This time the reactive power flow and its optimization are considered. A Windows type application created based on the model is presented. This powerful tool can be used to evaluate the total loss when an electrical network based on RES has to be designed. It can be used to optimize the links between nodes, the reactive power control devices optimal placement and optimal reactive power generation/compensation. From these operations result decreased losses (costs).

The Smart Grid of the future will be created starting from Smart Microgrids. The modelling of Mic... more The Smart Grid of the future will be created starting from Smart Microgrids. The modelling of Microgrids and the simulations of their real time steady state status is presented in the paper. The model is created using graphs. A Windows type application created based on the model is presented. This powerful tool can be used to evaluate the total loss when an electrical network has to be designed and it can be used to optimize the links between nodes and the storage dealt devices optimal placement and optimal power, too. From these operations result decreased losses (costs).

A linear time and space algorithm for construction of a binary tree from the pre-order and post-o... more A linear time and space algorithm for construction of a binary tree from the pre-order and post-order traversals is presented. The solution is not always unique. The number of solutions is calculated and an optimal time and space method to find all the solutions is shown.

Rairo-operations Research, 2008

ABSTRACT The problem is to modify the capacities of the arcs from a network so that a given feasi... more ABSTRACT The problem is to modify the capacities of the arcs from a network so that a given feasible flow becomes a maximum flow and the maximum change of the capacities on arcs is minimum. A very fast O(mlog(n)) time complexity algorithm for solving this problem is presented, where m is the number of arcs and n is the number of nodes of the network. The case when both, lower and upper bounds of the flow can be modified so that the given feasible flow becomes a maximum flow is also discussed. The algorithm proposed can be adapted to solve this problem, too. The inverse minimum flow problem considering l ∞ norm is also studied.

Yugoslav Journal of Operations Research, 2008

The general inverse maximum flow problem (denoted GIMF) is considered, where lower and upper boun... more The general inverse maximum flow problem (denoted GIMF) is considered, where lower and upper bounds for the flow are changed so that a given feasible flow becomes a maximum flow and the distance (considering l 1 norm) between the initial vector of bounds and the modified vector is minimum. Strongly and weakly polynomial algorithms for solving this problem are proposed. In the paper it is also proved that the inverse maximum flow problem where only the upper bound for the flow is changed (IMF) is a particular case of the GIMF problem.

Scientific Annals of Cuza University, 2006

Journal of Applied Mathematics and Computing, 2007

In this paper we consider the inverse minimum flow (ImF) problem, where lower and upper bounds fo... more In this paper we consider the inverse minimum flow (ImF) problem, where lower and upper bounds for the flow must be changed as little as possible so that a given feasible flow becomes a minimum flow. A linear time and space method to decide if the problem has solution is presented. Strongly and weakly polynomial algorithms for solving the ImF problem are proposed. Some particular cases are studied and a numerical example is given.

The theory and applications of network flows is probabily the most important single tool for appl... more The theory and applications of network flows is probabily the most important single tool for applications of digraphs and perhaps even of graphs as a whole. In this paper we study minimum flow an algorithm in bipartite networks with unit capacities combining an algorithm for minimum flow in bipartite networks with an algorithm for minimum flow in unit capacity networks. Finally, we present the applications of the minimum flow problem in bipartite networks with unit capacities.

The Smart Grid of the future will be created starting from Smart Microgrids. The modeling of Micr... more The Smart Grid of the future will be created starting from Smart Microgrids. The modeling of Microgrids and the simulations of their real time steady state status is presented in the paper. The model is created using graphs. This paper continues a previous one, which dealt with the active power flow. This time the reactive power flow and its optimization are considered. A Windows type application created based on the model is presented. This powerful tool can be used to evaluate the total loss when an electrical network based on RES has to be designed. It can be used to optimize the links between nodes, the reactive power control devices optimal placement and optimal reactive power generation/compensation. From these operations result decreased losses (costs).

The Smart Grid of the future will be created starting from Smart Microgrids. The modelling of Mic... more The Smart Grid of the future will be created starting from Smart Microgrids. The modelling of Microgrids and the simulations of their real time steady state status is presented in the paper. The model is created using graphs. A Windows type application created based on the model is presented. This powerful tool can be used to evaluate the total loss when an electrical network has to be designed and it can be used to optimize the links between nodes and the storage dealt devices optimal placement and optimal power, too. From these operations result decreased losses (costs).