Informatics Publishing Limited

Manoj Singhal ¹, Girish Sharma ², R. K. Chauhan ³

Affiliations
1 Department of Information Technology, Accurate Institute of Management and Technology, Greater Noida (U.P.), IN
2 Department of Computer Applications, Bhai Parmanand Institute of Business Studies, New Delhi, IN
3 Departement of Computer Science and Applications, Kurukshetra University, Kurukshetra, IN

Abstract

We know that binary decision diagram is a data structure that is used to store a Boolean function. They are used to find out the terminal reliability of a computer communication network. To generate the binary decision diagram of a given computer communication network, we need to order the edges of the given computer communication network because the size of the binary decision diagram is dependent on the ordering of the variables (edges). There are three types of variable ordering; optimal, good and bad ordering. Optimal ordering are those ordering which generate minimum size binary decision diagram. In this paper we have shown that if a directed computer communication network has m disjoints min-paths then m! optimal variable orderings exist to generate the binary decision diagrams of the given computer communication network.

Keywords

Binary Decision Diagrams (BDD), Computer communication Network (CNN), Directed Acyclic Graph (DAG), Modified Binary Decision Diagrams (MBDD).

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Manoj Singhal ¹

Affiliations
1 Accurate Institute of Management and Technology Knowledge Pak III, Greater Noida, IN

Abstract

In this paper i have adopted an efficient approach for calculating the reliability of the computer communication network with the help of binary decision diagram. The computer communication network has imperfect nodes and imperfect links. It means the nodes as well as the communication links may fail with known probability. The network is represented in the form of a directed graph. First i have found the reliability of the given network by applying the inclusionexclusion formula, which is an exact method to find the reliability of a network and then i have found the reliability of the given network with binary decision diagram. To find the reliability via binary decision diagram, we must order the nodes and the communication links of the given network by applying a proposed heuristic approach. I have found that the reliability obtained via binary decision diagram is equal to the reliability obtained by inclusion-exclusion formula. I have also shown that the generated binary decision diagram is of the minimum size.

Keywords

Binary Decision Diagrams (BDD), Directed Acyclic Graph (DAG), Computer communication Network (CNN), Modified Binary Decision Diagram (MBDD), Ordered Binary Decision Diagram (OBDD).

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Manoj Singhal ¹, R. K. Chauhan ², Girish Sharma ³

Affiliations
1 Dept. Of MCA, Academy of Business and Engineering Sciences, Ghaziabad (U.P.), IN
2 Deptt. of Computer Science and Applications, Kurukshetra University, Kurukshetra, IN
3 Deptt. of MCA, Bhai Parmanand Institute of Business Studies, Delhi, IN

Abstract

In this paper we adopted a new approach for evaluating the size of the BDD and also generated modified binary decision diagrams for calculating the reliability of the given directed computer communication network. We have also shown that these modified binary decision diagrams are of minimum size. Conclusively, we can say that more than one optimal variable ordering may exist for finding the reliability of particular networks.

Keywords

Binary Decision Diagrams (BDD), Directed Acyclic Graph (DAG), Computer Communication Network (CNN), Ordered Binary Decision Diagrams (OBDD).

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