Approximation Algorithms for Data Placement Problems

13 years 4 months ago

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We develop approximation algorithms for the problem of placing replicated data in arbitrary networks, where the nodes may both issue requests for data objects and have capacity for storing data objects, so as to minimize the average data-access cost. We introduce the data placement problem to model this problem. We have a set of caches F, a set of clients D, and a set of data objects O. Each cache i can store at most ui data objects. Each client j D has demand dj for a specific data object o(j) O and has to be assigned to a cache that stores that object. Storing an object o in cache i incurs a storage cost of fo i , and assigning client j to cache i incurs an access cost of djcij. The goal is to find a placement of the data objects to caches respecting the capacity constraints, and an assignment of clients to caches, so as to minimize the total storage and client access costs. We present a 10-approximation algorithm for this problem. Our algorithm is based on rounding an optimal sol...

Ivan D. Baev, Rajmohan Rajaraman, Chaitanya Swamy

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