Korea Institute of Science and Technology

Yonsei University

Hye Sung Kim

Seong-Lyun Kim

Ji Young Byun

Han Moe Cha

Jee Min Kim

Seung-Woo Ko

Jung Gu Kim

Hyeon Joon Shin

Dong Hwa Kum

Provided is a device for allocating a dynamic frequency for a secondary user in a cognitive radio network. The device includes: an OP map generation unit for generating an opportunity map, which represents a probability of successful communication of the secondary transmitter in each region of the cognitive radio network, by using one or more of spectrum sensing information, which is received from a spectrum sensor that has completed sensing and includes identifier information, location information, and a sensing measurement matrix, an access request message, which is received from the secondary transmitter and includes identifier information, location information, and operable band information, and the density and transmission powers of primary transmitters; and a response message generation unit for generating a response message, which includes the channel having the highest probability of successful communication and the probability of successful communication, based on the generated map.

Method and device for allocating dynamic frequency for secondary user in cognitive radio network

A Mg&mdash;Ca sacrificial anode according to the present invention is disclosed, which is capable of providing a melts protection effect during a dissolution of Mg by adding Ca, which is a low melting point modification element, to Mg and obtaining characteristics which are equal to or better than a conventional Mg alloy group sacrificial anode in view of an open circuit potential and an anode efficiency.

Mg-Ca sacrificial anode

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Seoul, South Korea

Hye Sung Kim