Doo Hwan Lee

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IEEE 802.16e wireless metropolitan area networks refers to the new standard for broadband wireless access (BWA), which targets to support wireless Internet service up to 2 Mbps. Existing draft version of standard proposes OFDM(A)-based handover process system, which consists of network topology acquisition, scanning, initial ranging, authorization, and(More)
IEEE 802.15.4 Low Rate Wireless Personal Area Network (LR-WPAN) is developed for emerging applications for industrial automation, home networking, wireless sensor networks, etc. In this paper, we propose a new scheme to enhance IEEE 802.15.4 in order to enable the fast delivery of packets, which announce the emergent situations or events of the network.(More)
In this paper, ranging process in IEEE 802.16e OFDMA systems is analyzed and performance is evaluated. Ranging process provides initial network entry, uplink synchronization, and system coordination. In the system initialization state, multiple users transmit randomly selected ranging code set and BS conducts multiple user identification by ranging code(More)
BACKGROUND AND OBJECTIVES Predictive factors of mortality in acute coronary syndrome (ACS) patients with left ventricular dysfunction were analyzed during 5-year clinical follow-up after percutaneous coronary intervention (PCI). SUBJECTS AND METHODS A total of 329 ACS consecutive patients (64.6±11.3 years, 227 males) who underwent PCI from January 2001 to(More)
  • Doo Hwan Lee
  • 2005 1st IEEE and IFIP International Conference…
  • 2005
For uplink synchronization, IEEE 802.16e wireless metropolitan area networks group has suggested ranging for OFDMA based uplink system. However, it is inherently vulnerable to the channel selectivity and other users' interferences at low SNR. In this paper, a novel detection scheme for OFDMA ranging has been proposed using modified generalized chirp-like(More)
Performance of conventtonal vector quanttzers tmproves as the rate and/or dtmenston are Increased However, such Improved performance comes at the cost of exponenttally mcreasmg complextty. Because of thts, use of the conventtonal vector quarmzers IS generally bmtted to lower rates and/or dtmensions. One way to reduce thts exponential growth m complextty 1s(More)
The aim of this study was to evaluate whether the clinical outcomes were associated with socioeconomic status (SES) in patients with acute myocardial infarction (AMI) who underwent percutaneous coronary intervention (PCI). The author analyzed 2,358 patients (64.9 ± 12.3 yr old, 71.5% male) hospitalized with AMI between November 2005 and June 2010. SES was(More)