Support for temporal text-containment queries is of interest in a number of contexts. In previous papers we have presented two approaches to temporal text-indexing, the V2X and ITTX indexes. In this paper, we first present improvements to the previous techniques. We then perform a study of the space usage of the indexing approaches based on both analytical models and results from indexing tempo...

Tradeoff between time and cost is an important issue in planning a project. This paper deals with a stochastic Time-Cost Tradeoff Problem (TCTP) in PERT network of project management. All activities are subject to linear cost function and assumed to be exponentially distributed. The aim of this problem is to maximize the project completion probability with a pre-known deadline to a predefined p...

Cryptanalytic time memory tradeoff algorithms are generic one-way function inversion techniques that utilize pre-computation. Even though the online time complexity is known up to a small multiplicative factor for any tradeoff algorithm, false alarms pose a major obstacle in its accurate assessment. In this work, we study the expected pre-image size for an iteration of functions and use the res...

We present BlowFish, a distributed data store that admits a smooth tradeoff between storage and performance for point queries. What makes BlowFish unique is its ability to navigate along this tradeoff curve efficiently at finegrained time scales with low computational overhead. Achieving a smooth and dynamic storage-performance tradeoff enables a wide range of applications. We apply BlowFish to...

Given m distributed data streams A1, . . . ,Am, we consider the problem of estimating the number of uniqueidentifiers in streams defined by set expressions over A1, . . . ,Am. We identify a broad class of algorithms for solvingthis problem, and show that the estimators output by any algorithm in this class are perfectly unbiased and satisfystrong variance bounds. Our ana...

An arithmetic formula is an expression involving only the constant 1, and the binary operations of addition and multiplication, with multiplication by 1 not allowed. We obtain an asymptotic formula for the number of arithmetic formulas evaluating to n as n goes to infinity, solving a conjecture of E. K. Gnang and D. Zeilberger [5]. We give also an asymptotic formula for the number of arithmetic...

The time - cost tradeoff problem is one of the most critical issues in the project scheduling field and so far, a lot of research has been done with a variety of quantitative and qualitative approaches on this subject. In this research, we intend to provide a two - objective mathematical model which balances crash and delay for activities. So that it provides the right tools for decision makers...

We consider the deadline problem and budget problem of the nonlinear time-cost tradeoff project scheduling model in a series-parallel activity network. We develop fully polynomial time approximation schemes for both problems using K-approximation sets and functions, together with series and parallel reductions.