Doo Hwan Lee

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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)
Ranging process is proposed for the coordination between mobile station and base station in IEEE 802.16e OFDMA systems. It consists of ranging detection process (RDP), uplink resource allocation, and registration. Among them, RDP is the first step of ranging process and the core of wireless access algorithm in IEEE 802.16e OFDMA systems. Thus, it is(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)
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)
Purpose: This study was designed to evaluate the question of whether a computed tomography (CT) protocol without an unenhanced phase could be used for diagnosis of appendicitis in pediatric patients who visited the emergency department (ED) with acute non-traumatic right lower abdominal pain. Methods: We retrospectively selected 100 samples from pediatric(More)
To reduce the complexity of scheduling while exploiting the advantages of TDMA-based data collection, we propose TKN-TWN, a token-scheduled multi-channel data collection protocol. The TKN-TWN uses two tokens to arbitrate data-packet transmissions and associates the ownership of tokens with transmission slot assignment. For the reduction of scheduling(More)