Ιδρυματικό Αποθετήριο
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Πολυτεχνείο Κρήτης
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| URI | http://purl.tuc.gr/dl/dias/631575F9-96CE-47A5-AD98-AA0A97BE0108 | - |
| Αναγνωριστικό | http://www.madgik.di.uoa.gr/sites/default/files/acm_pods98_pp79-88.pdf | - |
| Γλώσσα | en | - |
| Μέγεθος | 10 pages | en |
| Τίτλος | Throughput-competitive admission control for continuous media databases | en |
| Δημιουργός | Garofalakis Minos | en |
| Δημιουργός | Γαροφαλακης Μινως | el |
| Δημιουργός | Ioannidis, Yannis, 1930- | en |
| Δημιουργός | Ozden Banu | en |
| Δημιουργός | Silberschatz Avi | en |
| Περίληψη | Multimedia applications require a guaranteed level of service for accessing Continuous Media (CM) data, such as video and audio. To obtain such guarantees, the database server whom the data is residing must employ an admission control schomo to limit the number of clients that can be served concurrently, We investigate the problem of on-line admission control where the decision on whether to accept or reject a request must bc made without any knowledge about future rcqucsts. Employing competitive analysis techniques, we address the problem in its most general form with the following key contributions: (1) we prove a tight upper bound on the competitive ratio of the conventional Work-Conserving (WC) policy, showing that it is within a factor e of the optimal clairvoyant strategy that knows the entire request scquoncc in advance, where A is the ratio of the maximum to minimum request length (that is, time duration), and p is the maximum fraction of the server’s bandwidth that a rcqucst can demand; (2) we prove a lower bound of Q(s) on tho competitive ratio of any deterministic or randomized admission control scheme, demonstrating an exponential gap bctwccn greedy and optimal on-line solutions; (3) WC propose simple deterministic schemes based on the idea of lrandwidth prepartitioning that guarantee competitive ratios within a small constant factor of log A (i.e., they are near-optimal) for sufficiently large server bandwidth; (4) we introduce a novel admission control policy that partitions tha scrvcr bandwidth based on the expected popularities of different request lengths and present a set of preliminary cxpcrimontal results that demonstrate the benefits of our policy compared to WC. We believe that our results offer new insights to other optimization problems that arise in CM data management, including data placement and load bnlancing in distributed CM databases. | en |
| Τύπος | Δημοσίευση σε Συνέδριο | el |
| Τύπος | Conference Publication | en |
| Άδεια Χρήσης | http://creativecommons.org/licenses/by/4.0/ | en |
| Ημερομηνία | 2015-12-01 | - |
| Ημερομηνία Δημοσίευσης | 1998 | - |
| Θεματική Κατηγορία | Media databases | en |
| Βιβλιογραφική Αναφορά | M. Garofalakis, Y. Ioannidis, B. Ozden and A. Silberschatz, "Throughput-competitive admission control for continuous media databases", in Conference SIGMOD/PODS98 Special Interest Group on Management of Data (SIGMOD)/Principles of Data Base Systems (PODS), June 1998, pp. 79-88. | en |
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