Jang-Yeon Lee

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Beta-D-Xylosidase (EC has been purified from ginsenoside Ra-metabolizing Bifidobacterium breve K-110, which was isolated from human intestinal microflora. beta-D-Xylosidase was purified to apparent homogeneity by a combination of ammonium sulfate precipitation, QAE-cellulose, butyl-toyopearl, hydroxyapatit and Q-Sepharose column chromatographies(More)
The design of medium access control (MAC) in wireless sensor networks (WSNs) poses several key factors such as energy conservation, bandwidth utilization, throughput, etc. This paper proposes a new MAC protocol referred to as DEE-MAC which reduces energy consumption by making the idle nodes sleep to reduce idle listening using synchronization at cluster(More)
In this paper, we make MAC protocol improvements for performance enhancement of multihop ad-hoc wireless networks. A node in ad-hoc wireless networks can transmit a packet only when the medium is available, and while a packet is being transmitted, no other node is allowed to transmit a packet if they are in carrier sensing range. Carrier sensing range can(More)
In this paper, we present an adaptive hopping algorithm fora wireless personal area network (WPAN) receiver applying a frequency hopping. Analytical results based on the closedform solutions for the aggregate throughput show that the proposed hopping algorithm using two defined hopping criteria is more effective method for the all kinds of interferers and(More)
The CSMA/CA driven MAC protocols withhold packet transmissions from exposed stations when they detect carrier signal above a certain threshold. This is to avoid collisions at other receiving stations. However, this conservative scheme often exposes many stations unnecessarily, and thus minimizes the utilization of the spatial spectral resource. In this(More)
The many-to-one multihop traffic pattern of Wireless Sensor Networks (WSNs) puts a great challenge on enhancing the event-to-sink data delivery throughput. Because, in CSMA/CA driven medium access control protocols, contention of the shared medium raises both at the event detection area and near the sink, which in turn increases the packet collisions(More)
In mobile ad hoc networks, the large amount of control overheads associated with discovering and maintaining end-to-end routing path information may not be tolerable. In this paper, we present the design and simulation of a new approach for IEEE 802.11 MAC based on the multipath routing information for ad hoc networks. The routing information about multiple(More)