tailieunhanh - Integrated Research in GRID Computing- P7

Integrated Research in GRID Computing- P7:The deployment process for adaptive Grid applications does not finish when the application is started. Several activities have to be performed while the application is active, and actually the deployment system must rely on at least one permanent process or daemon. | 108 INTEGRATED RESEARCH IN GRID COMPUTING of their entry node in A s horizon. For example in Fig. 1 duplicates produced by queries originating from node K are added up to the counters kept for node J while duplicates produced by queries originating from nodes E F G H I are added up to the counters kept for node D. The intuition for the choice of this criterion is that shortest paths differ in the first hops and when they meet they follow a common route. For this criterion to be effective a message should store the identities of the last k nodes visited where k is the horizon value. Horizon Hops criterion This criterion combines the two previous ones. Duplicates are counted separately on each one of A s incident edges for each node in A s horizon. Nodes outside A s horizon are grouped together according 1 to their distance in hops from A and 2 to the entry node of their messages in A s horizon. In what follows we present three variations of the feedback-based algorithm that are based on the grouping criteria used. The algorithm using the hops criterion is shown below. The groups formed by node A in the graph of Fig. 1 according to the hops criterion are shown in Table 1. Feedback-based algorithm using the Hops criterion 1. Warm-up phase Each incoming non-duplicate query message is forwarded to all neighbors except the upstream one. For each incoming duplicate query message received a duplicate feedback message is returned to the upstream node. Each node A for each incident edge e counts the percentage of dupli-c. cate feedback messages produced on edge e for all queries messages originating k hops away. Let us denote this count by De k 2. Execution phase Each node A forwards an incoming non-duplicate query message that a. originates k hops away over its incident edges e if the count De k does not exceed a predefined threshold. Table 1. Groups for the Horizon criterion based on the example of Fig. 1. Hops 1 2 3 4 5 6 7 Groups formed by node A B C D J E K F G H I The