Byeong Gi Lee

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In this paper, we rigorously investigate the energy minimization problem for wireless packet networks with automatic repeat request (ARQ) capability. We first formulate the problem for the single-hop case under constrained packet delay and reliability and derive the necessary and sufficient condition for the optimal transmission power at each ARQ stage. We(More)
In this paper, we investigate the problem of the lifetime maximization in wireless sensor networks under the constraint of end-to-end transmission success probability, by adopting a cross-layer strategy that considers physical layer (i.e., power control), MAC layer (i.e., retransmission control) and network layer (i.e., routing protocol) jointly. We(More)
We present a new wireless scheduling algorithm based on the cumulative distribution function (cdf) of user transmission rates and also present a simple modification of it to limit the maximum starving time. This cdf-based scheduling (CS) algorithm selects the user for transmission based on the cdf of user rates in such a way that the user whose rate is high(More)
In this paper, we present an algorithm that performs base station (BS) switching-on/off and user terminal (UT) association jointly in heterogeneous networks composed of cellular networks and wireless local area networks (WLANs). We first formulate a general problem which minimizes a total cost function, which is designed to balance the energy consumption of(More)
In this paper we established a theory on lossless pole-zero modeling of speech signals for the description of nasal sounds. The theory is based on a generalized vocal tract tube model which consists of the main vocal tract, the oral tract, and the nasal tract. We first derived a new pole-zero type transfer function, which turned out to be a generalized(More)