Ayça Ak

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  • D De, E Er, R R St, T To, O Ol, L Ly +13 others
We consider the following queuing system which arises as a model of a wireless link shared by multiple users+ There is a finite number N of input flows served by a server+ The system operates in discrete time t ϭ 0,1,2, + + + + Each input flow can be described as an irreducible countable Markov chain; waiting customers of each flow are placed in a queue+(More)
We investigate fast simulation techniques for estimating the unreliability in large Markovian models of highly reliable systems for which analytical0numerical techniques are difficult to apply+ We first show mathematically that for " small " time horizons, the relative simulation error, when using the importance sampling techniques of failure biasing and(More)
  • Ta A Ar, R Ra, Ja A Av, V Vi, I Id, D Di +5 others
We study the scheduling of jobs in a system of two interconnected service stations, called Q 1 and Q 2 , on m~m Ն 2! identical machines available in parallel, so that every machine can process any jobs in Q 1 or Q 2 + Preemption is allowed+ Under certain conditions on the arrival, service, and interconnection processes, we determine a scheduling policy that(More)
  • A Ak, Kr Ra, Na Aj Ji I, Ya Ah, Hy Ya, A A Ab +2 others
  • 2006
Cryptographic hash functions are an important building block for a wide range of applications such as digital signatures. In this paper, we give an overview of cryptographic hash functions; classification, definitions, and their basic security. We give special emphasis on cryptographic dedicated hash functions with summarizing the recent attacks on MD5 and(More)
  • Ya A Ao, O O Zh, H Ha, A Ao, A A An, N Nd +11 others
  • 2006
We study a single-product periodic-review inventory model in which the ordering quantity is either zero or at least a minimum order size+ The ordering cost is a linear function of the ordering quantity, and the demand in different time periods are independent random variables+ The objective is to characterize the inventory policies that minimize the total(More)
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