Abstract: A current-reusing bleeding mixer capable of providing a higher conversion gain, linearity and lower noise figure employing a field-effect transistor includes a first to a fourth transistor and a first and a second load element. The first transistor amplifies a radio frequency (RF) signal. The second and the third transistor, each connected to the first transistor, receive a balanced local oscillator (LO) signal to mix it with the RF signal. The first and the second load element are connected between a supply voltage source and the second transistor and between the supply voltage source and the third transistor, respectively. The fourth transistor, connected between the supply voltage source and the first transistor, amplifies the RF signal and bleeds a current from the supply voltage source.

Abstract: A texture description method in a frequency domain for extracting texture features by transforming and Gabor-filtering an input image into an image of the frequency domain, and a texture-based retrieval method thereof are provided. The texture description method in the frequency domain includes: a first step of transforming an image of a time domain into an image of the frequency domain; a second step of filtering the transformed image using a Gabor filter having N×M filter regions, where N and M are respective predetermined positive integers; a third step of extracting feature values of the image that has been Gabor-filtered in respective channels of the frequency domain division layout corresponding to the N×M filter regions of the Gabor filter; and a fourth step of deciding a texture descriptor of the image on the basis of the feature values of the image.

Abstract: In a Conductor-Backed Coplanar Waveguide (CBCPW) structure, an effective dielectric constant of a parallel plate waveguide is higher than that of a Coplanar Waveguide (CPW), so that a parallel plate leakage is generated. To reduce the parallel plate leakage, the present invention provides air cavities, whose dielectric constant is low, in a multilayer circuit so that the effective dielectric constant of the parallel plate waveguide of the CBCPW structure can be lowered.

Abstract: Disclosed are a system and a method for statistically predicting an interaction probability between proteins, and more particularly to a system and a method for predicting an interaction probability between an unknown protein pair based on information obtained by analyzing differences between interacting and non-interacting sets of protein pairs from the view point of domain combination. The prediction method includes the steps of (a) obtaining appearance frequency information of a designated domain combination selected from each of interacting and non-interacting sets of protein pairs, and storing the obtained appearance frequency information, (b) determining a probability equation applied to predict the interaction between two proteins using the stored appearance frequency information of the domain combination, and (c) obtaining an interaction probability value between the two proteins from the determined probability equation.

Abstract: In an apparatus and a method for generating and verifying an identity based blind signature by using bilinear parings, a trust authority generates system parameters and selects a master key. Further, the trust authority generates a private key by using a signer's identity and the master key. The signer computes a commitment and sends the commitment to the user. The user blinds a message and sends the blinded message to the signer. The signer signs the blinded message and sends the signed message to the user. Thereafter, the user unblinds the signed message and then verifies the signature.

Abstract: In a method and an apparatus for generating and verifying an identity based proxy signature by using bilinear pairings, a trust authority generates system parameters and selects a master key. Further, the trust authority generates private keys of an original signer and proxy signer based on the original signer's identity and the proxy signer's identity, respectively. The original signer generates a signed warrant, computes values for verifying the signature of the signed warrant and then transfers the signed warrant and the values to the proxy signer. Thereafter, the proxy signer verifies the signature of the signed warrant and then generates a proxy signature key. Finally, the proxy signer signs a delegated message and the verifier verifies the proxy signature.

Abstract: In a wideband variable frequency voltage controlled oscillator, an LC resonance circuit determines an oscillation frequency based on an externally inputted voltage signal. A negative resistance generating circuit generates a signal having the oscillation frequency determined by the LC resonance circuit. A buffer circuit transfers the oscillation frequency generated by the negative resistance generating circuit to a load. A variable capacitor connecting circuit connects the negative resistance generating circuit and the buffer circuit to transfer the signal having the oscillation frequency from the negative resistance generating circuit to the buffer circuit.

Abstract: An adaptive bias circuit is provided for an amplifier module including a RF power amplifier for amplifying an input signal to generate an output signal, wherein the bias circuit receives the input signal to adjust a driving current to control a quiescent current of the RF power amplifier. The adaptive bias circuit includes means for providing the driving current to the bias circuit and means for drawing a bypass current from the providing means to reduce the driving current in response to the input signal, wherein the quiescent current is reduced when the driving current is reduced and the bypass current increases when the input signal is reduced.

Abstract: A power amplifier for use in a mobile handset includes an amplifying transistor for generating an output of the mobile handset, a bias circuit having a bias transistor and providing a bias current to bias the amplifying transistor, and a bias current control circuit, responsive to a control signal, for adjusting the bias current to control an operation current of the amplifying transistor. The control signal is generated by the mobile handset, and the control signal is determined by a power level of the output of the mobile handset.

Abstract: A power amplifier for use in a mobile handset includes an amplifying transistor, a bias circuit including a bias transistor, the bias circuit providing a bias current to bias the amplifying transistor, and a bias current control circuit, responsive to fluctuation in a reference voltage and variation in temperature, for adjusting the bias current to control an operation current of the amplifying transistor.

Abstract: A fingerprints embedment system employing an anonymous fingerprinting method using a bilinear Diffie-Hellman problem includes three participants, introduces system parameters and generates a public key and a secret key of each of the first and the second participant. The anonymous fingerprinting method registers information on the first participant to a third participant based on the system parameters and the public and the secret key of the first participant, wherein the third participant issues a certificate based on the information of the first participant and authenticates a fairness of the first participant based on the certificate.

Abstract: In an apparatus and a method for generating and verifying an identity based blind signature by using bilinear parings, a trust authority generates system parameters and selects a master key. Further, the trust authority generates a private key by using a signer's identity and the master key. The signer computes a commitment and sends the commitment to the user. The user blinds a message and sends the blinded message to the signer. The signer signs the blinded message and sends the signed message to the user. Thereafter, the user unblinds the signed message and then verifies the signature.

Abstract: A transimpedance amplification apparatus includes a signal source for generating a current signal, a source follower stage, a common source stage and a shunt feedback resistor. The source follower stage having a source follower structure receives the current signal to reduce an impedance of the signal source. The common source stage, following the source follower stage, driven by the reduced signal source impedance, amplifies the current signal to extend a frequency bandwidth of the current signal and buffers the amplified signal with the extended frequency bandwidth thereof maintained, wherein the reduced signal source impedance serves to extend a frequency bandwidth of the common source stage. The shunt feedback resistor, which is installed between the source follower stage and the common source stage, adjusts an input DC bias of the source follower stage and increasing a transimpedance gain of the common source stage.

Abstract: A cryptosystem employing an identity-based ring signature by using bilinear pairings, which includes a user, a signer and a trusted authority, generates a set of system parameters shared by the user and the signer, generates a public key and a private key for the user and the signer by using the set of system parameters, thereby transmitting the generated public and the private keys to the user and the signer through a secure channel, respectively. The user conceals content of a message, requests a ring signature for the content-concealed message to the signer, and thereafter, verifies validity of the ID-based ring signature. The signer produces the ring signature based on identity (ID) of the user, thereby forming an ID-based ring signature for the content-concealed message.

Abstract: A bias control circuit for a power amplifier including an RF amplifier having a transistor for power amplification, comprises two components. A first component is a bias circuit having an active bias transistor operating in an active mode and connected to a predetermined Vref pin to provide the transistor for power amplification with a base current and a second component is a bias current control circuit having another active bias transistor connected to a predetermined Vcon pin and turned on or off depending on a high or a low mode of the Vcon pin to thereby control a base current and a quiescent current of the transistor for power amplification.

Abstract: In a multilayer RF module, a plurality of vertically stacked ceramic layers include a first to a third ceramic layers. Each of the first and the third ceramic layers has a circuit component thereon and the second ceramic layer is located between the first and the third ceramic layers and is provided with at least one or more air cavities filled with air, the air cavities being vertically aligned with the circuit components of the first and the third ceramic layers.

Abstract: A turbo encoding and decoding method and apparatus iteratively performs its decoding process as many times as the number of decoding times adaptively determined according to an amount of errors caused in a transmitted information bit stream so as to correct the errors, wherein the amount of errors is detected by checking a state of parity bits inserted into information bits during a turbo encoding process. The turbo encoder first inserts the parity bits into the information bits and encodes the parity bit inserted information bits to thereby produce the information bit stream to be transmitted.