Dong-Jun Lee

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The Intermational Mobile Telecommunications IMT-2000 system uses a microcell concept to provide multimedia services and to support increasing number of users. However, in a microcell system, the number of handoffs is greatly increased. To solve this problem, a multitier cellular structure is proposed, in which high-speed mobile terminals (MTs) are serviced(More)
In typical mobile communication systems, mobile station (MS) location information is updated when the MS crosses location area boundary or registration timer is expired. When a call attempt occurs, sequential paging rather than blanket paging is used to reduce the paging cost. In this letter, we propose a new location update scheme in which to increase the(More)
Code-division multiple-access (CDMA) cellular systems use soft handoff. Although the capacity of CDMA systems is interference-limited in nature, channel shortages may occur because soft handoff uses several channels simultaneously. To cope with this problem, we propose an improved handoff method that borrows channels from stationary calls participating in(More)
OBJECTIVES This study was performed to determine the incidence of herpes zoster and seroprevalence of varicella-zoster virus (VZV) in young adults of South Korea, where VZV seroprevalence remains relatively high. METHODS In South Korea, military service is compulsory for all healthy young men and hence those in military service might provide a reflection(More)
In this study, a robust QoS Scheduling scheme using alternate paths for recovery from link failures is proposed in the IEEE 802.15.4e with tree-based network structure. In the proposed scheme, margin slots used for alternate paths are included in the scheduling. Simulation results show that the margin slots of the proposed scheme results in higher(More)
A new signal-to-interference ratio (SIR)-based call admission control (CAC) scheme is proposed in DS-CDMA systems. In this scheme, a new call is accepted by a base station (BS) if the SIR’s at that specific BS and its nearby, not necessarily adjacent, BS’s can be guaranteed to be higher than some threshold value after accepting the new call. The SIR’s of(More)
This study was performed to determine the incidence and seroprevalence of hepatitis A virus (HAV) infections in young soldiers in the Republic of Korea Army. From January 2000 through December 2004, a total of 147 hepatitis A cases were reported to the Armed Forces Medical Command. The annual incidence rates were 7.4 per 100,000 persons in 2000, 1.6 in(More)