Sk Planet Co., Ltd.

Sk Telecom Company, Ltd.

Youngshin Yoon

Joosik Lee

Sungjun Kim

Youngil Kim

Jonghyun Kim

Sunshin An

Jaesic Jeon

Sangwoo Rhie

Sangmok Sohn

Soonjae Jeong

Youngmin Ji

Hosung Joh

Wonjun Lee

Donghwan Lee

Hyunmin Jang

Sukil Kang

Junghee Han

Provided are an address book information service system, and a method and a device for an address book information service therein, whereby: a terminal device in the address book information service system sets groups in an address book according to category information and transmits group information on the set groups and preset user information to a service device; the service device searches new address book information corresponding to the group information on the basis of the location of a user by using the group information and the user information and transmits the searched new address book information to the terminal device; and the terminal device automatically registers the received new address book information in the address book, thereby enabling the user to easily look up new address book information.

Address book information service system, and method and device for address book information service therein

The present invention relates to a method for measuring a location of a radio frequency identification (RFID) reader by using beacons, and an RFID system for measuring a location of a moving RFID reader in an RFID system comprising: a plurality of beacon devices for emitting beacons; an RFID tag for transmitting pre-stored information by using radio frequency identification; and an RFID reader for calculating a current location using a plurality of at least three beacons wherein the RFID reader receives the plurality of beacons from the plurality of beacon devices while moving, and receiving the information from the RFID tag by using the radio frequency identification. According to the present invention, it is possible to increase the accuracy of the location measurement of a moving RFID reader in an RFID system because the location of the RFID reader is measured in consideration of propagation environments.

Method for measuring location of radio frequency identification reader by using beacon

The present invention relates to a method for determining an optimal frame size for tag collision prevention in an Aloha-based RFID system in which frame sizes limited to a certain unit are used to identify tags, the method including the steps of using an RFID for: (a) calculating an estimated optimal frame value for the RFID reader identifying the tags; (b) calculating expected time delays per tag of a left-hand frame size and a right-hand frame size, which show the smallest differences with respect to the estimated optimal frame value, among the frame sizes; (c) comparing, the expected time delay per tag of the left-hand frame size with that of the right-hand frame size; and (d) determining a frame size which has a smaller expected time delay per tag, between the left-hand frame size and the right-hand frame size, to be an optimal frame size.

Method for determining optimal frame size for tag collision prevention in RFID system

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Seoul, South Korea

Youngshin Yoon