The problem of matching nuts and bolts is the following : Given a collection of n nuts of distinct sizes and n bolts such that there is a oneto-one correspondence between the nuts and the bolts, nd for each n ut its corresponding bolt. We c a n only compare nuts to bolts. That is we c a n neither compare nuts to nuts, nor bolts to bolts. This humble restriction on the comparisons appears to make this problem very hard to solve. In fact, the best deterministic solution to date is due to Alon et al. 1] a n d takes (n log 4 n) time. Their solution uses (e cient) graph expanders. In this paper, we g i v e a simpler O(n log 2 n) time algorithm which uses only a simple (and not so e cient) expander.

s.kumar@asu.edu

This paper proposes a new scheduling policy for cluster-based servers called DAS (Deferred Assignment Scheduling). The main idea in DAS is to defer scheduling as much as possible in order to make better use of the accumulated information on job sizes. In broad outline, DAS operates as follows: (1) incoming jobs are held by the dispatcher in a buffer; (2) the dispatcher monitors the number of jobs being processed by each server; (3) when the number of jobs at a server queue drops below a prescribed threshold, the dispatcher sends to it the shortest job in its buffer.To gauge the efficacy of DAS, the paper presents simulation studies, using various data traces. The studies collected response times and slowdowns for two cluster configurations under multi-threaded and multi-process back-end server architectures. The experimental results show that in both architectures, DAS outperforms the Round-Robin policy in all traffic regimes, and the JSQ (Join Shortest Queue) policy in medium and heavy traffic regimes.

No abstract

Despite attractive theoretical properties, Vickrey auctions are seldom used due to the risk of information revelation and fear of cheating.