We consider indexing and range searching in metric spaces. The best method known is AESA, in practice requiring the fewest number of distance evaluations to answer range queries. The problem with AESA is its space complexity, requiring storage for Θ(n) distance values to index n objects. We give several methods to reduce this cost. The main observation is that exact distance values are not need...

In this paper we show that the energy reductions obtained from using two techniques, data remapping and voltage/frequency scaling of off-chip bus and memory, combine to provide interesting trade offs between energy, execution time and power. Both methods aim to reduce the energy consumed by the memory subsystem. Data remapping is a fully automatic compile time technique applicable to pointer-in...

A method is introduced to incorporate sustainability considerations in the early design stages, while simultaneously accounting for supply chain factors, such as cost and lead time. Overall, this work is our first step in understanding the trade-offs between sustainability metrics and more traditional supply chain performance metrics (i.e., cost and lead time). Based on our understanding of the...

We establish trade-oos between time complexity and write-and access-contention for solutions to the mutual exclusion problem. The write-contention (access-contention) of a concurrent program is the number of processes that may be simultaneously enabled to write (access by reading and/or writing) the same shared variable. Our notion of time complexity distinguishes between local and remote acces...

A reversible Turing machine is one whose transition function is 1, so that no instantaneous description (ID) has more than one predecessor. Using a pebbling argument, this paper shows that, for any e > 0, ordinary multitape Turing machines using time T and space S can be simulated by reversible ones using time O(T +) and space O(S log T) or in linear time and space O(ST). The former result impl...

Population protocols are a popular model of distributed computing, in which randomly-interacting agents with little computational power cooperate to jointly perform computational tasks. Inspired by developments in molecular computation, and in particular DNA computing, recent algorithmic work has focused on the complexity of solving simple yet fundamental tasks in the population model, such as ...

Each of n processors has a value which should be transmitted to all other processors. This fundamental communication task is called gossiping. In a unit of time every processor can communicate with at most one other processor and during such a transmission each member of a communicating pair learns all values currently known to the other. Two important criteria of efficiency of a gossiping algo...

In this paper we focus on problems which do not admit a constant-factor approximation in polynomial time and explore how quickly their approximability improves as the allowed running time is gradually increased from polynomial to (sub-)exponential. We tackle a number of problems: For Min Independent Dominating Set, Max Induced Path, Forest and Tree, for any r(n), a simple, known scheme gives an...