Method and system for managing resources

A computer program product, comprising a physically tangible computer readable storage medium having a computer readable program code stored therein, said program code configured to be executed by a processor of a computer system to implement a method for generating a timing sequence for activating resources linked through time dependency relationships, said method comprising:

• providing a first Direct Acyclic Graph (DAG) having a simulation date and comprising multiple nodes and multiple directed edges, wherein each node of the multiple nodes represents a unique resource and is either a predefined Recovery Time Objective (RTO) node comprising a predefined RTO denoting a maximum elapsed time that the unique resource is permitted to remain in its current state or an undefined RTO node comprising a positive infinite value, wherein the multiple nodes comprise at least two predefined RTO nodes and at least zero undefined RTO nodes, wherein each directed edge of the multiple direct edges represents a time delay and directly connects two nodes of the multiple nodes in a direction from a predecessor node of the two nodes to a successor node of the two nodes, wherein a predecessor resource being the unique resource represented by the predecessor node has a time dependency on a successor resource being the unique resource represented by the successor node such that the predecessor resource requires the successor resource to be in the successor resource's target state no later than a time consisting of the simulation date incremented by the time delay;
• topologically sorting the nodes of the multiple nodes to order the multiple nodes in a dependency sequence of ordered nodes, such that each node in the dependency sequence whose unique resource has a time dependency on the unique resource of at least one other node in the dependency sequence is placed in the dependency sequence before each node of the at least one other node;
• in traversal of the ordered nodes in the dependency sequence, computing a corrected RTO for each ordered node in the dependency sequence as a function of (i) the predefined RTO of said each ordered node and, for each predecessor node connected to said each ordered node:
• (ii) the corrected RTO of said each predecessor node and (iii) the time delay represented by the edge that directly connects said each predecessor node to said each ordered node;
• after said computing the corrected RTO for each ordered node, calculating an estimated RTO as a corrected RTO for each ordered node remaining as an undefined RTO node, said estimated RTO calculated as a function of:
• (a) the corrected RTO of each successor node of each remaining undefined RTO node and (b) the time delay represented by the edge that directly connects each remaining undefined RTO node to said each successor node;
• and
• reordering the ordered nodes in the dependency sequence according to an ascending order of the corrected RTO of the ordered nodes to form an activation sequence of the multiple nodes defining a time ordering of activation of the unique resources represented by the multiple nodes.

A computer system comprising a processor and a computer readable memory unit coupled to the processor, said memory unit containing program code configured to be executed by the processor to implement a method for generating a timing sequence for activating resources linked through time dependency relationships, said method comprising:

• providing a first Direct Acyclic Graph (DAG) having a simulation date and comprising multiple nodes and multiple directed edges, wherein each node of the multiple nodes represents a unique resource and is either a predefined Recovery Time Objective (RTO) node comprising a predefined RTO denoting a maximum elapsed time that the unique resource is permitted to remain in its current state or an undefined RTO node comprising a positive infinite value, wherein the multiple nodes comprise at least two predefined RTO nodes and at least zero undefined RTO nodes, wherein each directed edge of the multiple direct edges represents a time delay and directly connects two nodes of the multiple nodes in a direction from a predecessor node of the two nodes to a successor node of the two nodes, wherein a predecessor resource being the unique resource represented by the predecessor node has a time dependency on a successor resource being the unique resource represented by the successor node such that the predecessor resource requires the successor resource to be in the successor resource's target state no later than a time consisting of the simulation date incremented by the time delay;
• topologically sorting the nodes of the multiple nodes to order the multiple nodes in a dependency sequence of ordered nodes, such that each node in the dependency sequence whose unique resource has a time dependency on the unique resource of at least one other node in the dependency sequence is placed in the dependency sequence before each node of the at least one other node;
• in traversal of the ordered nodes in the dependency sequence, computing a corrected RTO for each ordered node in the dependency sequence as a function of (i) the predefined RTO of said each ordered node and, for each predecessor node connected to said each ordered node:
• (ii) the corrected RTO of said each predecessor node and (iii) the time delay represented by the edge that directly connects said each predecessor node to said each ordered node;
• after said computing the corrected RTO for each ordered node, calculating an estimated RTO as a corrected RTO for each ordered node remaining as an undefined RTO node, said estimated RTO calculated as a function of:
• (a) the corrected RTO of each successor node of each remaining undefined RTO node and (b) the time delay represented by the edge that directly connects each remaining undefined RTO node to said each successor node;
• and
• reordering the ordered nodes in the dependency sequence according to an ascending order of the corrected RTO of the ordered nodes to form an activation sequence of the multiple nodes defining a time ordering of activation of the unique resources represented by the multiple nodes.