Young Myoung Ko

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In this paper, we consider time-varying multi-server queues with abandonment and retrials. For their performance analysis, fluid and diffusion limits utilizing strong approximations have been widely used in the literature. Although those limits are asymptotically exact, they may not accurately approximate performance of multi-server queues even if the(More)
BACKGROUND Bladder dysfunction induced by spinal cord injury (SCI) can become problematic and severely impair the quality of life. Preclinical studies of spinal cord injury have largely focused on the recovery of limb function while neglecting to investigate bladder recovery. OBJECTIVE The present study was performed to investigate and review the effect(More)
PURPOSE This study attempted to overcome the limitations of previous systematic reviews to determine the overall treatment efficacy and safety of prostatic arterial embolization compared with standard therapy. MATERIALS AND METHODS Meta-analyses were done of randomized, controlled and single group trials. Meta-regression analysis of the moderator effect(More)
In real stochastic systems, the arrival and service processes may not be renewal processes. For example, in many telecommunication systems such as internet traffic where data traffic is bursty, the sequence of inter-arrival times and service times are often correlated and dependent. One way to model this non-renewal behavior is to use Markovian Arrival(More)
Data centers consume a phenomenal amount of energy which can be significantly reduced by appropriately allocating resources using technologies such as virtualization, speed scaling and powering off servers. We propose a unified methodology that combines these technologies under a single framework to efficiently operate data centers. In particular, we(More)
The relationship between distribution of urologists and mortality of bladder and prostate cancers has not been clearly established. The aim of this study was to investigate the relationship between uneven distribution of urologists and urologic cancer specific mortality at country level. Data from the National Health Insurance Service and National(More)