Abstract: A cognitive radio communication apparatus and method to control a sensing operation. The cognitive radio communication apparatus includes an information receiver to receive channel state information associated with a channel occupancy state of a primary system from at least one sensing node of a secondary system; a sensing control unit to control a sensing period of the at least one sensing node according to a change pattern of the channel occupancy state, based on the channel state information; and a control information transmitter to transmit control information associated with the controlled sensing period to at least one member node of the secondary system.

Abstract: A resistive frequency mixing apparatus includes a first frequency mixer having a source follower FET, and a second frequency mixer having a common source FET. The resistive frequency mixing apparatus perform a frequency mixing of an RF depending on an LO signal to generate a down-converted IF signal when the RF signal is applied to the source follower FET and the LO signal is applied to the common source FET. Further, the resistive frequency mixing apparatus performs a frequency mixing of an IF signal depending on an LO signal through the use of the source follower FET to produce an up-converted RF signal when the IF signal is applied to the common source FET and the LO signal is applied to the common source FET.

Abstract: Disclosed are a forward discrete/inverse-discrete Fourier transform device and method for optical orthogonal frequency division multiplexing (OFDM) communication and a transmitting and receiving apparatus.The forward inverse-discrete Fourier transform device includes N 1:N splitters for splitting subcarrier signals received from N inputs corresponding to the number of optical frequencies of subcarriers, a phase shift delay array module for shifting phases of the split signals from the 1:N splitters, N N:1 power couplers for coupling signals output from the phase shift delay array module, a time delay array module for performing time delay on optical OFDM symbols from the N:1 power couplers, and an N:1 power coupler for coupling signals output from the time delay array module.

Abstract: An optical burst switching (OBS) system and a method using duplicate optical burst transmission is provided. In accordance with the present invention, optical bursts do not have the same priority when the duplicate optical bursts are transmitted in an OBS network so that a burst loss rate due to blocking can be reduced. Optical bursts do not have the same priority when the duplicate optical bursts are transmitted in an OBS network, so that a burst loss rate due to the blocking can be reduced. After an optical burst control packet is transmitted on a signal channel using a unidirectional reservation manner in the OBS, a problem such as optical burst loss due to the blocking can be prevented even when the optical burst is transmitted on a data channel after an offset time is elapsed without any response messages.

Abstract: A variable gain amplifier including: a differential amplification unit amplifying and outputting a difference between a first input signal and a second input signal inputted via a first input terminal and a second input terminal, respectively, according to a first bias current of the first input terminal and second input terminal, to a first output terminal and a second output terminal; a diode-connected load unit comprising loads diode-connected to the first output terminal and second output terminal, respectively, the load receiving a second bias current; and a gain control unit controlling a gain between the input terminals and the output terminals of the differential amplification unit by controlling the size of the first bias current and second bias current.

Abstract: A method and an apparatus for performing handover in a mobile communication network are provided. The method of performing handover in a mobile communication network includes: obtaining a service providing time period and a utility function on a candidate network basis; obtaining a selection function of each of the candidate networks using the utility function and the service providing time period; and selecting a network for handover among the plurality of mobile networks using the selection function. Therefore, in consideration of user satisfaction and a network service quality, utility functions are defined and by selecting a network for handover using the utility functions, a network suitable for a user environment can be effectively selected and thus it is possible to perform handover that has a performance and a cost suitable for user request and that can maximize a quality of a mobile service.

Abstract: Disclosed herein is a method for protecting and restoring a link in an OBS network. The method includes a step of transmitting/receiving a liveness-confirming message for confirming liveness of the link between an up-node and a down-node respectively connected to both ends of the link at a predetermined message transmission period, to judge whether a fault is generated on the link, a step in which the up-node and down-node respectively update link information when it is judged that the link fault is not generated, and a step of restoring the link having the fault using predetermined restoration channel information based on an offered load measured when the link is in a normal state when it is judged that the link fault is generated. Accordingly, a link having a problem can be effectively protected and restored in the OBS network.

Abstract: The present invention relates to a switch, a negative resistance cell, and a differential voltage controlled oscillator using the same. The present invention includes a first signal line provided in a first direction, a second signal line provided in parallel with the first signal line, and first to fourth gate electrodes, first to third source electrodes, and first to fourth drain electrodes formed between the first signal line and the second signal line, and provides a switch having electrodes in the order of the first gate electrode, the first drain electrode, the second gate electrode, the first source electrode, the third gate electrode, the second drain electrode, the fourth gate electrode, the second source electrode, the fifth gate electrode, the third drain electrode, the sixth gate electrode, the third source electrode, the seventh gate electrode, the fourth drain electrode, and the eighth gate electrode.

Abstract: Provided are a network-coding apparatus and method which can increase a data communication capacity in a communication environment to which an error-correction code (ECC) is applied. The network-coding apparatus includes a received signal processing unit receiving at least two signals, and decoding the at least two received signals; and a transmission signal processing unit receiving the at least two decoded signals from the received signal processing unit, merging the at least two decoded signals, and generating a merged transmission signal.

Abstract: Provided is a fine frequency synchronization method of a WiBro system, and particularly, a fine frequency synchronization method which measures a spread degree of a received signal of an adjacent subcarrier using orthogonality of PN sequences and thereby estimates a frequency offset, in a base station or a wireless repeater without using a GPS receiver. The fine frequency synchronization method includes: (a) performing despreading on received adjacent subcarrier sequences, using a PN sequence transmitted from a transmitting party; (b) obtaining ratios of correlative values obtained by the despreading; and (c) estimating a frequency offset on the basis of the ratio of correlative values. Accordingly, fine frequency offset estimation with relatively low complexity is possible without using a GPS receiver in a WiBro environment where interference signals of other base stations or repeaters exist.

Abstract: An apparatus and method for detecting a signal in a receiver by maximum likelihood (ML) are provided, in which symbols are detected according to the number of transmit antennas of a transmitter and a modulation scheme, channels are estimated, an equivalent channel matrix corresponding to the estimated channels is determined, a permuted equivalent channel matrix is determined by multiplying the equivalent channel matrix by a predetermined permutation matrix, the permuted equivalent channel matrix is QR decomposed, a hard decision is performed on predetermined symbols among the detected symbols using a received signal resulting from the QR decomposition, and the log likelihood ratios (LLRs) of the hard-decided symbols are determined.

Abstract: System and method provide an on-line high-performance diagnosis service for cardiovascular disorders. A client requests a high-performance diagnosis by transmitting real electrocardiographic treatment data and magnetocardiographic treatment data of a human body being a treatment object and virtual heart simulation parameters to a medical service server. The medical service server, in response to the diagnosis request, analyzes the real electrocardiographic treatment data to generate an electrocardiographic analysis result, and performs a virtual heart simulation using the simulation parameters to generate a pseudo electrocardiogram and magnetocardiogram.

Abstract: An apparatus and a method are provided for detecting N number of TX signals in a MIMO wireless communication system. The apparatus includes an RF processor, a channel estimator, and a signal detector. The RF processor converts signals, received through multiple antennas, into baseband signals. The channel estimator estimates channel information of the respective antennas by using the received signals. The signal detector arranges the baseband signals of the respective antennas on the basis of the channel information, calculates a threshold value of each stage, and selects symbols with a cumulative metric smaller than or equal to the threshold value as candidates at each stage, to detect a TX signal vector with N number of symbols.

Abstract: A circuit for improving amplification and noise characteristics of a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), and a frequency mixer, an amplifier and an oscillator using the circuit are provided. A gate terminal of the MOSFET is connected to a body terminal of the MOSFET through a capacitor and the gate and body terminals of the MOSFET are connected to a current source to simultaneously provide a signal to both the gate terminal and the body terminal, in order to improve amplification and noise characteristics of the MOSFET. As a result, a higher level of amplification and a lower level of noise than the conventional art can be obtained.

Abstract: Disclosed are a contents encryption method, and a system and method for providing contents through a network using the contents encryption method. In order to provide contents through the network more securely, at least one piece of contents and corresponding metadata are recursively multi-encrypted at least once, and encrypted data are then provided. In particular, encrypted positions of the contents and corresponding decryption information are expressed as metadata, and the metadata include parameter information on respective encryption tools used for multi-encryption, an order of the applied encryption tools, positions of the encryption tools, and a list of encryption tool substitutes. The metadata are provided when the contents are provided. Therefore, the contents provider and receiver can more safely and systematically manage the metadata including contents decryption information, and multimedia are efficiently protected, managed, and controlled.

Abstract: A method and apparatus for encoding multimedia content and a method and system for applying encoded multimedia content are provided. The method of applying encoded multimedia content includes: storing in a database, a multimedia application format (MAF) file, including at least one single track which includes a header having information indicating media data, media data, and media metadata, and application data indicating information on an application method of the media; and browsing or sharing the MAF file stored in the database. According to the methods and apparatuses, even when a user does not have a special application or a function applying metadata, integrated general-purpose use of multimedia content, such as effectively browsing or sharing with others the multimedia content, is enabled.

Abstract: Provided are a system and method for identifying a peer-to-peer (P2P) application service. The method includes the steps of: (a) collecting an Internet protocol (IP) packet and generating a flow; (b) identifying the P2P application service on the basis of a port number using the generated flow; (c) when the P2P application service is identified in step (b), verifying the identified application service; (d) when it is verified that the identification is not correct, or the P2P application service is not identified in step (b), identifying the P2P application service on the basis of a payload; (e) when the P2P application service is identified in step (d) or it is verified in step (c) that the identification is correct, generating a SET table using a flow of the identified P2P application service; and (f) identifying the P2P application service for a flow not identified in either step (b) or step (d) using the SET table.

Abstract: Disclosed is a heterodyne receiver for low noise and image frequency repression, comprising: a low noise amplifier for receiving an input signal from an antenna and amplifying the signal while reducing a noise figure of the input signal; and a frequency converter for receiving both the input signal outputted from the low noise amplifier and a local oscillation signal, filtering the signals to repress gain of the input signal at an image frequency band and increase gain of the input signal at a signal frequency band, and converting the frequency of the signals to the intermediate frequency band.

Abstract: Provided is a method of compensating for energy loss and eliminating inter-symbol interference (ISI) and inter-chip interference (ISI) in wireless signals, and a rake receiver for wireless LANs adopting the same. The rake receiver compensates for energy loss of a CCK signal transmitted in a multi-path wireless channel environment and eliminates ISI and ICI from the received CCK signal because a DFE structure per chip used for calculating ICI components, is connected in parallel with a DFE structure per symbol, thus eliminating ISI and ICI components.

Abstract: A method of generating multi-channel local oscillation frequencies in an ultra wide band communication system having multiple channels of identical bandwidth, the method including: generating at least one reference frequency; generating a plurality of auxiliary frequencies by dividing and multiplying the at least one reference frequency; and generating a plurality of first local oscillation frequencies by mixing the reference frequency and at least some of the plurality of auxiliary frequencies with other auxiliary frequencies, respectively, wherein each of the auxiliary frequencies used in the mixing is greater than an interval between the frequency being mixed and an outermost frequency in the ultra wide band.