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State-machine-based replication is an effective way to increase the availability and dependability of mission-critical applications. However, all practical applications contain some degree of non-determinism. Consequently, ensuring strong replica consistency in the presence of application non-determinism has been one of the biggest challenges in building dependable distributed systems. In this Study, the authors propose a classification of common types of application non-determinism with respect to the requirement of achieving Byzantine fault tolerance (BFT), and present the design and implementation of a BFT framework that controls these types of non-determinism in a systematic manner. [ABSTRACT FROM AUTHOR]

A new and simple calibration algorithm using general node equations is proposed in the calibration of the n-port vector network analyser (VNA). The crosstalk error term is considered in the error model to achieve high precision. With the general node equations deduced from the general flow graph, the S-parameters can be finally derived. The actual S-parameters of a four-port device can be corrected and compared with measurement results by Agilent VNA E5071B. The good agreement attests the precision of the calibration algorithm. [ABSTRACT FROM AUTHOR]

A proactive recovery scheme based on service migration for long-running Byzantine fault-tolerant systems is described. Proactive recovery is an essential method for ensuring the long-term reliability of fault-tolerant systems that are under continuous threats from malicious adversaries. The primary benefit of our proactive recovery scheme is a reduced vulnerability window under normal operation. This is achieved in two ways. First, the time-consuming reboot step is removed from the critical path of proactive recovery. Second, the response time and the service migration latency are continuously profiled and an optimal service migration interval is dynamically determined during runtime based on the observed system load and the user-specified availability requirement. [ABSTRACT FROM AUTHOR]

The authors propose the design and control of a biologically-inspired biomimetic robotic fish capable of three-dimensional locomotion. The mechanical configuration and the hardware system of the robotic fish are described. The control architecture of the robotic fish is constructed based on central pattern generator (CPG). A model for a system of coupled non-linear oscillators is established to construct CPG and has been successfully applied to the four-link robotic fish. The CPGs are modeled as non-linear oscillators for joints and inter-joint coordination is achieved by altering the connection weights between joints. Coordinated gait patterns of rhythmic movements for swimming can be produced by modulating simple control parameters in the CPG model. The CPG-based method shows elegant and smooth transitions between swimming gaits, and enhanced ability to cope with transient perturbations because of non-linear characteristic. A series of swimming tests are designed to give speed evaluation and turning maneuver analysis. The effectiveness of the proposed method is confirmed via simulation and some experimental results. [ABSTRACT FROM AUTHOR]

A minimum component high frequency Gm-C wavelet filter structure is presented. A simple function from Maclaurin series approximation is used and the current-mode follow-the-leader feedback structure is employed. For the seventh-order Marr wavelet bandpass filter, the proposed implementation architecture contains only seven ideal Gm-C integrators for poles and one transconductor for zeros. A 100 MHz wavelet filter has been designed and simulated in 0.18 µm CMOS and results show the feasibility of the proposed approach. [ABSTRACT FROM AUTHOR]

40 Gbit/s operation of a novel monolithically integrated wavelength converter consisting of a sampled grating DBR laser, a long SOA and a delay interferometer (DI)-MZI is reported. Error-free 40 Gbit/s wavelength conversion for three different probe wavelengths, and 10 Gbit/s intensity modulation by the DI-MZI for the optical label coding, are demonstrated. [ABSTRACT FROM AUTHOR]

A new design of a non-volatile magnetic flip-flop is presented. The use of a magnetic tunnel junction (MTJ) to store the information brings non-volatility to logic circuits and promises zero standby power. It is based on the thermally assisted switching (TAS) approach and the pre-charge sense amplifier. By using STMicroelectronics' CMOS 0.13um design kit and a precise TAS-MTJ compact model, transient functional simulations and Monte Carlo statistical analysis have been carried out to show, respectively, its low power and high reliability performances. [ABSTRACT FROM AUTHOR]

A simple optical pulse generator based on a semiconductor optical amplifier (SOA) is demonstrated with an easy-generated external optical pulse sequence. Using the cross-gain modulation and self-phase modulation effects inside an SOA, the simple optical pulse generator generates a 10 GHz 3.8 ps optical pulse train with an extremely low timing jitter of 60 fs. [ABSTRACT FROM AUTHOR]

Ge/Ag/Ni metallisation with an overlay of Ti/Pt/Au was investigated as ohmic contact on an InAlAs/InGaAs/InP high electron mobility transistor (HEMT) structure. Its electrical characteristics were measured after annealing and compared with those of AuGe/Ni/Au and AuGe/Ni ohmic contacts. It was found to have ohmic contact resistance as low as those for AuGe/Ni/Au and AuGe/Ni metallisations but with much higher annealing temperatures and larger processing latitude. [ABSTRACT FROM AUTHOR]

Presents a theoretical model for the calculation of X-ray sensitivity of a pixilated detector by using the Shockley-Ramo theorem. Introduction to direct conversion flat panel digital X-ray image detectors; Description about X-ray sensitivity; Imaging characteristics of photoconductive at panel X-ray image detectors; Measurement of presampling modulation transfer function of the prototype detector.

An improvement to kernel principal component analysis (KPCA) to produce computationally efficient KPCA-based feature extraction is proposed. This improvement is applicable to all cases no matter whether the samples in the feature space have zero mean or not. Experiments on several benchmark datasets show that the improvement performs well in classification problems. [ABSTRACT FROM AUTHOR]

A simple and compact scheme for the phase-locking of two photonic crystal fibre (PCF) lasers is presented and studied experimentally. In the experiments, the two PCF lasers are mutually injected by direct transmission coupling of the fibre lasers. The interference strips are of high contrast ratio and stability even in high power operation. 39W coherent output power is obtained with combining efficiency of 97.2%. [ABSTRACT FROM AUTHOR]

A novel dual-band microwave bandpass filter (BPF) is proposed using a dual-mode stepped impedance resonator (DSIR) and a three-mode stepped impedance resonator (TSIR). Either of the SIRs can not only separately generate one passband but also control the passband performance. Owing to the intrinsic characteristics of the SIRs, each passband has a pair of transmission zeros to improve the selectivity. A dual-band filter located at 1.57 GHz (GPS application) and 2.4 GHz (WLAN application) is designed and fabricated. Good agreements are obtained between measured and simulated S-parameters. [ABSTRACT FROM AUTHOR]