Abstract: Provided is an apparatus and method for searching for address book information. To this end, the present invention, upon receiving a search request message for searching address book information from a client, checks a search preference, searches for the address book information based on the checked search preference, applies a priority to the found address book information to create a final search result, creates a response message including the created final search result, forwards the response message to the client, and updates the preset search preference based on the final search result, thereby providing a search result optimized for a user.

Abstract: A method and apparatus for supporting mobility of a mobile terminal in a Visible Light Communication (VLC) system. The method includes activating only necessary light sources for VLC considering the mobility of the mobile terminal, instead of using total light sources for VLC. Consequently, power consumption can be significantly reduced.

Abstract: A visible light communication method and terminal are provided for communicating with a visible light coordinator which discriminates between at least one communication area cell that includes at least one light source and a boundary area positioned between the communication area cell and another communication area cell adjacent to the communication cell area, and which provides time division visible light communication. Data of the visible light communication terminal is received from the visible light coordinator using a first time slot in a first communication area cell determined according to a position of the visible light communication terminal. The visible light coordinator is communicated with using a second time slot assigned from the visible light coordinator, when the visible light communication terminal is located in a boundary area of the first communication area cell. The second time slot has not been assigned to the visible light communication terminal.

Abstract: Provided is an apparatus and method to restore a signal using minimum value sampling, more particularly, a signal restoring apparatus and method using minimum value sampling, which are capable of effectively preventing deterioration of a restored signal caused by aliasing occurring when minimum value sampling of an input signal is performed in order to restore a signal. The apparatus to restore a signal using the minimum value sampling includes a storage unit to store a sample value obtained through the minimum value sampling of an input signal in a predetermined sampling interval; a position determination unit to determine the position of the sample value in the sampling interval; and a restoration unit to restore the input signal using the stored sample value with respect to the determined position.

Abstract: A pointing method, medium, and system detecting a synchronization signal from a plurality of light sources sequentially blinking at predetermined periods, detecting position information of the light sources by driving a video camera in synchronization with the synchronization signal, removing noise from among observed light sources by using the position information, and calculating a pointed to position by using the position information of the non-noise light sources. Provided is also a pointing reception method, medium, and system using a plurality of light sources blinking sequentially at predetermined periods, receiving the position information corresponding to light sources presenting the signals received by a pointing device and the position information pointed by the pointing device, and changing output data with respect to the pointed position information.

Abstract: A system, medium, and method conducing a user's breathing, in which a sound generated during a user's exhale and/or an ambient temperature change occurring during the exhale is sensed to measure a respiratory waveform of the user. Respiratory information of the user may then be produced from the respiratory waveform, and when the respiratory information of the user is different from normal respiratory information of the user, breathing information according to the normal respiratory information may be provided to the user so the user can use the same to modify their breathing.

Abstract: A method and apparatus for supporting mobility of a mobile terminal in a Visible Light Communication (VLC) system. The method includes activating only necessary light sources for VLC considering the mobility of the mobile terminal, instead of using total light sources for VLC. Consequently, power consumption can be significantly reduced.

Abstract: A pointing apparatus and method and a pointer display apparatus and method using a virtual region which generate a virtual region corresponding to a detected display region, convert coordinates of a location, and display a pointer at the converted coordinates. The pointing device includes a region detector detecting a display region, which displays a pointer, using at least one received signal; a virtual region generator generating the virtual region corresponding to the display region and having an aspect ratio equal to that of the display region; a coordinate converter converting coordinates of a location, which is pointed at by the pointing device, in the virtual region into ratios of the coordinates of the location to a size of the virtual region; and a coordinate ratio transmitter transmitting the ratios.

Abstract: A method and an apparatus are provided for guaranteeing terminal mobility in a time division visible light communication system. In resource assignment in a position where the visible light communication terminal changes a cell, the terminal is assigned a resource to be used in a next cell in a cell boundary area from a communication coordinator, thereby guaranteeing the continuous mobility. The visible light communication system informs the terminal of cell boundary notice information for easily informing the terminal of the cell definition so that the terminal can recognize that the terminal is currently located in the cell boundary and is necessary to change the resource.

Abstract: A method and apparatus for a sensor network having a plurality of reference nodes and a sensor node that enables the sensor node to compute a relative position through transmission range control and position mapping. In transmission range control, each reference node sends location information signals to the sensor node while varying transmission power. In position mapping, the sensor node forms a grid of vertical and horizontal lines corresponding to a square area defined by the neighboring reference nodes, extracts coordinates of intersections in the grid belonging to a shared region between areas covered by location information signals of various transmit power levels from the neighboring reference nodes, and sets the position of the sensor node to the middle points of the extracted coordinates. Each reference node sends a location information signal when a random backoff time expires after reception of a location information request signal.

Abstract: A method and system for transmitting data from a base station to a mobile station in a wireless communication system using a multiple hop relay scheme is In a multi-hop system having a plurality of nodes, performing bidirectional data transmission between the nodes comprises: grouping the plurality of nodes into a first node group to a fourth node group, and assigning data transmission intervals to the grouped node groups at each frame, the data transmission intervals dividing each frame in time; receiving, by a second group node, data from an upper group node at a first frame and, at the same time, receiving, by a third group node, data from a lower group node; and transmitting by the second group node data to the upper group node at a second frame and, at the same time, transmitting by the third group node data to the lower group node.

Abstract: A method and apparatus for allocating resources of a Visible Light Communication (VLC) terminal in a VLC system. The VLC terminal receives a beacon message from a base station, coordinates time synchronization with the base station, searches for an available wavelength channel, constructs available wavelength channel information, and transmits an initial access request using a basic time slot channel and a basic wavelength channel. The base station considers the available wavelength channel information and a current channel allocation condition, allocates an appropriate channel, and transmits channel allocation information to the VLC terminal. The VLC terminal and the base station communicate data with each other using an allocated time slot channel included in the channel allocation information and an allocated wavelength channel included in the channel allocation information.

Abstract: A method and apparatus are provided for outputting a visibility frame for a communication link connection during a communication link release in a Visible Light Communication (VLC) system. A transmitting-side VLC device determines a visibility frame output type according to a communication mode to be performed. The communication mode and the visibility frame output type are transmitted to a receiving-side VLC device. The receiving-side VLC device is communicated with according to the communication mode and it is determined whether a communication link is released while performing communication according to the communication mode. When the communication link is released, outputting a visibility frame according to the visibility frame output type.

Abstract: A method for performing communication in the wireless sensor network is disclosed. The upper node transmits a beacon message to the lower nodes, wherein the beacon message distinguishes an indirect transmission interval, in which the upper node transmits downlink data to the plurality of lower nodes, from a direct transmission interval adjacent to the indirect transmission interval, in which the upper node receives uplink data from the plurality of lower nodes. The lower nodes determine the indirect transmission interval and the direct transmission interval from the received beacon message. The downlink data is transmitted from the upper node to the lower nodes in the indirect transmission interval. The uplink data is transmitted from the lower nodes to the upper node in the direct transmission interval. When communication is performed between the upper node and the lower nodes, the data can be efficiently transmitted from the upper node to the lower nodes.

Abstract: A medium access control (MAC) frame provision method establishes security in an IEEE 802.15.4 network. A MAC frame is generated, which includes a MAC header, a payload field, and a frame check sequence (FCS) field, the payload field including relevant main data according to a frame type defined in the MAC header. A disguised decoy data sequence number (DSN) is generated and inserted into the MAC header. A real DSN, which is a corresponding transmission sequence number of the MAC frame, is generated and inserted into the payload field. The MAC frame is transmitted, including the encrypted payload field, to a counterpart node. A MAC ACK frame acknowledges reception of the transmitted MAC frame; and a DSN is compared in the received MAC ACK frame with the real DSN. An authentication of the counterpart node is performed when the received MAC ACK frame is equal to the real DSN.

Abstract: A packet transmission method for a WPAN that for alleviating traffic concentration in an active period and improving network throughput by controlling packet transmission timing in the active period. A packet transmission method for a wireless personal area network including a coordinator operating with a specific duty cycle and a plurality of devices includes determining, when a packet is generated, whether there is another packet waiting to be sent; determining, if there is no other packet waiting to be sent, whether the network is in an inactive period; setting, when network is in an inactive period, a backoff time; and sending the packet when the backoff time has expired. The packet transmission method controls an initial backoff value adaptively to a duty cycle of the network.

Abstract: A method is provided for supporting mobility of a Mobile Node (MN) in a multi-hop Internet Protocol (IP) network, in which an MN that has moved from a source Personal Area Network (PAN) to a target PAN, sends a Router Solicitation (RS) message with an option for requesting its profile to a gateway of the target PAN, and receives a Router Advertisement (RA) message from the gateway in response to the RS message. The RA message includes a home prefix of the MN as the requested profile. The method supports mobility of MNs, enables unicast communication, and facilitates efficient use of the network.

Abstract: A method is provided for registering a mobile router in an Internet Protocol version 6 over Low power Wireless Personal Area Network (6LoWPAN) network. The mobile router detects movement into a wireless network through the reception of a beacon message, and sends a Router Solicitation (RS) message requesting registration in the wireless network to a gateway. The gateway acquires an address of the mobile router from the RS message, stores the acquired address, assigns a new address to be used in the wireless network to the mobile router, and sends a Router Advertisement (RA) message with assigned address information and gateway address information, to the mobile router. The mobile router acquires the assigned address information and the gateway address information from the RA message.

Abstract: A system and method for exactly estimating a volume of traffic is provided when packets are transferred within the network. The system and method receive data packets from clients through a plurality of router-for-clients, and creating a flow information packet for estimating information about a flow, transfer the data packets and the created flow information packet to the destination router-for-client via a router-for-relay, calculate information about the traffic of a flow at the destination router-for-client through the flow information packets transferred from the router-for-clients, and estimate a volume of the traffic. Thus, the system and method can estimate the volume of the traffic on the network with respect to the aggregated flow defined by the router pair connected to the terminal or the external network when the traffic is actually introduced into the network, instead of the flows of each terminal and each destination.

Abstract: A method and device for determining an output of a visible frame in at Visible Light Communication (VLC) device are provided. A first VLC device determines whether to permit a second VLC device to generate visible frames, and transmits, to the second VLC device, visible frame information indicating whether the second VLC device is permitted to generate the visible frames.