Hyojin Ha

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  • Ma A Ar, R Rv V Vi I In N, N K Na, A Ak, K Ka, A Ay +10 others
  • 2004
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)
In this paper, we propose a novel analytical method, called scheduling time bound analysis, to find a tight upper bound of the worst-case response time in a distributed real-time embedded system, considering execution time variations of tasks, jitter of input arrivals, and scheduling anomaly behavior in a multi-tasking system all together. By analyzing the(More)
— Finding a tight upper bound of the worst-case response time in a distributed real-time embedded system is a very challenging problem since we have to consider execution time variations of tasks, jitter of input arrivals, scheduling anomaly behavior in a multi-tasking system, all together. In this paper, we translate the problem as an optimization problem(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)
We consider quadratic forms of martingale differences and establish a central limit theorem under mild and easily verifiable conditions+ By approximating Fourier transforms of stationary processes by martingales, our central limit theorem is applied to the smoothed periodogram estimate of spectral density functions+ Our results go beyond earlier ones by(More)
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