Subcube Allocation in Hypercube Computers
IEEE Transactions on Computers
Speed is as powerful as clairvoyance
Journal of the ACM (JACM)
Communications of the ACM
Fast allocation and deallocation with an improved buddy system
Acta Informatica
Upper bound for defragmenting buddy heaps
LCTES '05 Proceedings of the 2005 ACM SIGPLAN/SIGBED conference on Languages, compilers, and tools for embedded systems
An Algorithmic View on OVSF Code Assignment
Algorithmica
Online OVSF Code Assignment with Resource Augmentation
AAIM '07 Proceedings of the 3rd international conference on Algorithmic Aspects in Information and Management
Improving the Competitive Ratio of the Online OVSF Code Assignment Problem
ISAAC '08 Proceedings of the 19th International Symposium on Algorithms and Computation
ESA'07 Proceedings of the 15th annual European conference on Algorithms
A constant-competitive algorithm for online OVSF code assignment
ISAAC'07 Proceedings of the 18th international conference on Algorithms and computation
Theoretically good distributed CDMA/OVSF code assignment for wireless ad hoc networks
COCOON'05 Proceedings of the 11th annual international conference on Computing and Combinatorics
Dynamic assignment of orthogonal variable-spreading-factor codes in W-CDMA
IEEE Journal on Selected Areas in Communications
Constant-competitive tree node assignment
Theoretical Computer Science
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Given a complete binary tree of height h, the online tree node assignment problem is to serve a sequence of assignment/release requests, where an assignment request, with an integer parameter 0驴i驴h, is served by assigning a (tree) node of level (or height) i and a release request is served by releasing a specified assigned node. The node assignments have to guarantee that no node is assigned to two assignment requests unreleased, and every leaf-to-root path of the tree contains at most one assigned node. With assigned node reassignments allowed, the target of the problem is to minimize the number of assignments/reassignments, i.e., the cost, to serve the whole sequence of requests. This online tree node assignment problem is fundamental to many applications, including OVSF code assignment in WCDMA networks, buddy memory allocation and hypercube subcube allocation.Most of the previous results focus on how to achieve good performance when the same amount of resource is given to both the online and the optimal offline algorithms, i.e., one tree. In this paper, we focus on resource augmentation, where the online algorithm is allowed to use more trees than the optimal offline algorithm. By using different approaches, we give (1) a 1-competitive online algorithm, which uses (h+1)/2 trees and is optimal because (h+1)/2 trees are required by any online algorithm to match the cost of the optimal offline algorithm with one tree; (2) a 2-competitive algorithm with 3h/8+2 trees; (3) an amortized 8/3-competitive algorithm with 11/4 trees; (4) a general amortized (4/3+驴)-competitive algorithm with (11/4+4/(3驴)) trees, for 0驴驴4/3.