Showing papers in "Electronics Letters in 2002"
TL;DR: The results show that the measure represents how much information is obtained from the input images and is meaningful and explicit.
Abstract: Mutual information is proposed as an information measure for evaluating image fusion performance. The proposed measure represents how much information is obtained from the input images. No assumption is made regarding the nature of the relation between the intensities in both input modalities. The results show that the measure is meaningful and explicit.
1,059 citations
TL;DR: It is shown that repeated clipping and frequency domain filtering of an orthogonal frequency division multiplexing (OFDM) signal can significantly reduce the peak-to-average power ratio (PAPR) of the transmitted signal.
Abstract: It is shown that repeated clipping and frequency domain filtering of an orthogonal frequency division multiplexing (OFDM) signal can significantly reduce the peak-to-average power ratio (PAPR) of the transmitted signal. The technique causes no increase in out-of-band power. Significant PAPR reduction can be achieved with only moderate levels of clipping noise.
896 citations
TL;DR: In this article, a dominant mode leaky-wave antenna is proposed, which is a transmission line structure with radiating wavenumber increasing from negative to positive values, providing backward to forward scanning capability as the frequency is increased.
Abstract: A novel dominant mode leaky-wave antenna is proposed. This antenna is a transmission line structure with radiating wavenumber increasing from negative to positive values, providing backward to forward scanning capability as the frequency is increased. The characteristics and performances of the antenna are demonstrated by full-wave simulation and measurement results.
548 citations
TL;DR: In this article, a novel integrated mode size converter for single-mode Si wire waveguides is presented, which is constructed with two-dimensional tapered Si waveguide and overlaid high-index polymer waveguide.
Abstract: A novel integrated mode size converter for single-mode Si wire waveguides is presented. The mode size converter is constructed with two-dimensional tapered Si waveguides and overlaid high-index polymer waveguides. We calculated the proposed mode size converter characteristics, and fabricated 1.09 mm length Si wire waveguides with the converters. The measured loss of the mode size converter was 0.8 dB per conversion, and the total insertion loss through the sample with an Si wire waveguide was 3.5 dB.
502 citations
TL;DR: An ID-based authenticated two pass key agreement protocol which makes use of the Weil pairing is presented and its properties are discussed, including the ability to add key confirmation.
Abstract: An ID-based authenticated two pass key agreement protocol which makes use of the Weil pairing is presented. The protocol is described and its properties are discussed, including the ability to add key confirmation.
439 citations
TL;DR: In this paper, an identity-based signature scheme is presented which makes use of bilinear pairings on elliptic curves, similar to the generalised ElGamal signature scheme.
Abstract: An efficient identity-based signature scheme is presented which makes use of bilinear pairings on elliptic curves. This scheme is similar to the generalised ElGamal signature scheme. The security of the scheme is considered.
368 citations
TL;DR: A novel distortionless image data hiding algorithm based on integer wavelet transform that can invert the stego-image into the original image without any distortion after the hidden data are extracted is proposed.
Abstract: A novel distortionless image data hiding algorithm based on integer wavelet transform that can invert the stego-image into the original image without any distortion after the hidden data are extracted is proposed. This algorithm hides data into one (or more) middle bit-plane(s) of the integer wavelet transform coefficients in the middle and high frequency subbands. It can embed much more data compared with the existing distortionless data hiding techniques and satisfy the imperceptibility requirement. The image histogram modification is used to prevent greyscales from possible overflowing. Experimental results have demonstrated the validity of the algorithm.
286 citations
TL;DR: An iterative block decision feedback equaliser (IB-DFE) for single carrier modulation is proposed which operates on blocks of the receive signal, thus allowing the use of error correction codes on the feedback data signal.
Abstract: An iterative block decision feedback equaliser (IB-DFE) for single carrier modulation is proposed. Filtering operations are implemented by discrete Fourier transforms (DFTs) which yield a reduced computational complexity, for both filter design and signal processing, when compared to existing DFEs. Moreover, the new IB-DFE operates on blocks of the receive signal, thus allowing the use of error correction codes on the feedback data signal.
253 citations
TL;DR: In this article, a new magnetic waveguide is described, the operation of which is based on inductive coupling between resonant elements, and the general form of the dispersion equation is shown.
Abstract: A new magnetic waveguide is described, the operation of which is based on inductive coupling between resonant elements. The general form of the dispersion equation is shown. For a particular embodiment of the waveguide, consisting of 26 elements, the relative values of the currents are plotted and the travel of power from the first to the last element is shown by the streamlines of the Poynting vector. Application, as a magnetic guide for magnetic resonance imaging (MRI) is proposed.
231 citations
TL;DR: An authentication system, which does not require a password table to authenticate its users, is proposed, and introducing smart card and fingerprint verification so that the scheme can withstand message replaying attack and impersonation.
Abstract: An authentication system, which does not require a password table to authenticate its users, is proposed. By removing a password table, and introducing smart card and fingerprint verification, the scheme can be more secure and reliable. In addition, the scheme can withstand message replaying attack and impersonation.
225 citations
TL;DR: In this paper, the first microstructured singlemode non-silica optical fiber preform has been fabricated and the final drawn fibre has an effectively air-suspended 2 µm core.
Abstract: The fabrication of the first microstructured singlemode non-silica optical fibre is reported. Extrusion has been used for the first time to produce the microstructured fibre preform. The final drawn fibre has an effectively air-suspended 2 µm core. Singlemode guidance is observed from 633-1500 nm
TL;DR: Preliminary experiments prove the state transition sequences can express the different mode between normal action and intrusion behaviour in a more stable and simple manner.
Abstract: An anomaly intrusion detection method based on HMM is presented. The system call trace of a UNIX privileged process is passed to a HMM to obtain state transition sequences. Preliminary experiments prove the state transition sequences can express the different mode between normal action and intrusion behaviour in a more stable and simple manner.
TL;DR: In this paper, a pure silica core fiber with unprecedented low-loss of 0.1484 dB/km has been successfully fabricated, with a large effective area of 118 /spl mu/m/sup 2, and over 400 km distance transmission is possible with Raman amplification.
Abstract: A pure silica core fibre with unprecedented low-loss of 0.1484 dB/km has been successfully fabricated. With a large effective area of 118 /spl mu/m/sup 2/, this ultra-low-loss fibre extends transmission distance by 33% compared to conventional Ge-SMF, and over 400 km distance transmission is possible with Raman amplification.
TL;DR: In this paper, a method to design low-pass filters using defected ground structure (DGS) and compensated microstrip line is presented, which has a simple structure, small size, less discontinuities, and high power handling capability.
Abstract: A method to design lowpass filters (LPF) using defected ground structure (DGS) and compensated microstrip line is presented. Using the extracted equivalent elements of DGS and capacitive microstrip line, an LPF having no open stub, high impedance line, and tee- or cross-junction element, is designed. Only two DGS patterns and one broad microstrip line comprise the LPF Simple structure, small size (half of a conventional LPF), less discontinuities, and high power handling capability are obtained through the proposed LPF.
TL;DR: In this article, a stacked p-doped quantum dot active region was used to obtain a high characteristic temperature in GaAs-based 1.3 /spl mu/m lasers. But the performance was not as good as that achieved in this paper, where the room-temperature continuous-wave output power reached 27 mW with a 5.7 mA threshold.
Abstract: A stacked p-doped quantum dot active region is used to obtain a high characteristic temperature in GaAs-based 1.3 /spl mu/m lasers. A characteristic temperature of 232 K (213 K) is obtained between 0 and 81/spl deg/C for pulsed (continuous-wave) operation for lasers with 0.97 mm cavity length and five stacks of quantum dot layers. The room-temperature continuous-wave output power for a 0.65 mm cavity length reaches 27 mW with a 5.7 mA threshold.
TL;DR: In this article, an upstream traffic transmitter based on a Fabry-Perot laser diode (FP-LD) as modulator is proposed and demonstrated for wavelength division multiplexed (WDM) access networks.
Abstract: An upstream-traffic transmitter based on a Fabry-Perot laser diode (FP-LD) as modulator is proposed and demonstrated for wavelength division multiplexed (WDM) access networks. By injection-locking the FP-LD with the downstream wavelength at the optical network unit (ONU), the original downstream data can be largely suppressed while the upstream data can be transmitted on the same injection-locked wavelength by simultaneously directly-modulating the FP-LD.
TL;DR: In this article, multiple layers (up to 10) of InAs/InGaAs/GaAs quantum dots were used to enhance the optical gain of quantum dot laser emitting around 1.3 µm.
Abstract: Multiple layers (up to 10) of InAs/InGaAs/GaAs quantum dots considerably enhance the optical gain of quantum dot lasers emitting around 1.3 µm. A differential efficiency as high as 88% has been achieved in these lasers. An emission wavelength of 1.28 µm, threshold current density of 147 A/cm2, differential efficiency of 80%, and characteristic temperature of 150 K have been realised simultaneously in one device.
TL;DR: In this article, a new technique for UV direct writing of Bragg gratings in planar silica is presented, where the Bragg grating and the channels are defined simultaneously, conferring advantages in flexibility of design and grating performance.
Abstract: A new technique for UV direct writing of Bragg gratings in planar silica is presented. In this method the Bragg gratings and the channels are defined simultaneously, conferring advantages in flexibility of design and grating performance. Photosensitive Germanium doped silica-on-silicon produced by Flame Hydrolysis Deposition was used.
TL;DR: A class of optimum parallel interleavers regarding the access to storage elements is presented, which combine regularity with no latency in data transfer between the decoder module and intrinsic/extrinsic values memories, and show excellent BER performance.
Abstract: High-speed, low latency convolutional turbo codes require a parallel decoder architecture. To maximise the gain in speed, the interleaver also should have a parallel structure. Here, a class of optimum parallel interleavers regarding the access to storage elements is presented. They combine regularity (easy implementation) with no latency in data transfer between the decoder module and intrinsic/extrinsic values memories, and show excellent BER performance.
TL;DR: In this article, coupled cavity designs on two-dimensional square lattice photonic crystal slabs were used to demonstrate optically pumped indium arsenide quantum dot (ISAQD) laser at room temperature.
Abstract: Coupled cavity designs on two-dimensional square lattice photonic crystal slabs were used to demonstrate optically pumped indium arsenide quantum dot photonic crystal lasers at room temperature. Threshold pump powers of 120 and 370 μW were observed for coupled cavities including two and four defect cavities defined in optimised photonic crystals.
TL;DR: In this paper, a novel approach based on a PWLL for the generation of a.50% duty cycle clock from an input clock with arbitrary duty cycle has been described, which can also be used to generate an output clock with duty cycles from 25 to 75%.
Abstract: Conclusion: A novel approach based on a PWLL for the generation of a.50% duty cycle clock from an input clock with arbitrary duty cycle has been described. It can also be used to generate an output clock with duty cycles from 25 to 75%. The design has been shown to achieve this performance without affecting the jitter on one (sampling) edge of the input clock, which is very important for high-performance switched capacitor-based designs. 100
TL;DR: In this article, a 2D photonic crystal waveguide was optically characterised and the measured total insertion loss is below 19 dB in the waveguides with unpolarised light.
Abstract: Silicon-on-insulator-based 2D photonic crystal waveguides have been optically characterised. The measured total insertion loss is below 19 dB in the waveguides with unpolarised light. With the length mask technique, it is found that the photonic crystal waveguides show propagation losses below 4 dB/mm.
TL;DR: In this article, mode multiplexing and demultiplexing devices by using multimode interference couplers are proposed, where mode separating as well as superposing based on single and multiple self-imaging are utilised.
Abstract: Mode multiplexing and demultiplexing devices by using multimode interference couplers are proposed. Mode separating as well as superposing based on single and multiple self-imaging are utilised. Simulation results of wave propagation by the finite difference beam propagation method demonstrate the validity of the synthesis method.
TL;DR: In this paper, a printed dipole antenna with U-slotted arms is presented for dual-band operation in the 2.4 GHz and 5.2 GHz bands, which can generate a higher resonant mode for the 5 GHz band operation.
Abstract: Dual-band operation of a printed dipole antenna with U-slotted arms is presented. Due to the embedded U-shaped slots, two additional dipole arms are obtained in the proposed design, which form a second dipole antenna with a smaller length and which can generate a higher resonant mode for the 5.2 GHz band operation. By incorporating the original dipole arms designed for the 2.4 GHz band operation, the proposed antenna can perform WLAN operations in the 2.4 and 5.2 GHz bands.
TL;DR: In this article, an electrically pumped MOVPE-grown VCSEL on GaAs substrate with a GaInNAs active region emitting single mode at 1293 nm with record characteristics was reported.
Abstract: The authors report an electrically pumped MOVPE-grown VCSEL on GaAs substrate with a GaInNAs active region emitting single mode at 1293 nm with record characteristics. Continuous wave output power at room temperature with 1.4 mW, a threshold current of 1.25 mA and a data transmission rate of 10 Gbit/s has been realised.
TL;DR: A printed diversity monopole antenna for WLAN operation in the 2.4 GHz band is presented that has two highly decoupled ports and can provide spatial diversity to combat the multipath interference problem.
Abstract: A printed diversity monopole antenna for WLAN operation in the 2.4 GHz band is presented. The antenna comprises two orthogonal linear monopoles placed symmetrically with respect to a T-shaped ground plane between them. The antenna has two highly decoupled ports and can provide spatial diversity to combat the multipath interference problem.
TL;DR: In this article, the effect of SiN passivation of the surface of AlGaN/GaN transistors is reported, and the discrepancy in the DLTS peak amplitude is explained by the effect on the surface traps and underlines the surface nature of the major defect noticed in the device.
Abstract: The effect of SiN passivation of the surface of AlGaN/GaN transistors is reported. Current deep level transient spectroscopy (DLTS) measurements were performed on the device before and after the passivation by a SiN film. The DLTS spectra from these measurements showed the existence of the same electron trap on the surface of the device. The DLTS spectrum obtained from the measurement of the passivated device showed a significantly lower peak for this trap. The discrepancy in the DLTS peak amplitude is explained by the effect of the passivation on the surface traps and underlines the surface nature of the major defect noticed in the device.
TL;DR: In this article, a compact variable all-optical buffer using semiconductor quantum dot structures is proposed, which is achieved by slowing down the optical signal using an external control light source to vary the dispersion characteristic.
Abstract: A compact variable all-optical buffer using semiconductor quantum dot structures is proposed. The buffering effect is achieved by slowing down the optical signal using an external control light source to vary the dispersion characteristic of the medium. The theoretical model shows that a slow-down factor of more than 10/sup 4/ with negligible group velocity dispersion is achievable.
TL;DR: A circuit is described that is aimed at reliably amplifying edge time differences by a factor between 3 and 10 before measurement to enable greater accuracy.
Abstract: Accurate measurement of edge time differences down to 10 ps or less is required for tests of timing in digital systems. A circuit is described that is aimed at reliably amplifying these time differences by a factor between 3 and 10 before measurement to enable greater accuracy.
TL;DR: In this article, experimental results for an optical free-space high-speed link using direct modulated mid-infrared (DMIR) quantum cascade (QC) lasers are presented.
Abstract: Experimental results for an optical free-space high-speed link using direct modulated mid-infrared (/spl lambda/ = 8.1 /spl mu/m) quantum cascade lasers are presented. A total of 800 digitally encoded multimedia channels were transmitted. The reliability of the system against weather influence (fog) was experimentally compared to that of a near-infrared (/spl lambda/ = 0.85 /spl mu/m) link.