Acoustic Emission Burst Extraction for Multi-Level Leakage Detection in a Pipeline

Acoustic emission bursts are signal waveforms that include a number of consecutive imbrication transients with variable strengths and contain crucial information on the leakage phenomenon in a pipeline system. Detection and isolation of a burst against the background signal increases the ability of a pipe’s fault diagnosis system. This paper proposes a methodology using the Enhanced Constant Fault Alarm Rate (ECFAR) to detect bursts and exploit the burst phenomenon in acoustic emission. The extracted information from the burst waveform is used to distinguish several levels of leakage in a laboratory leak-off experimental testbed. The multi-class support vector machine in the one-against-all method is established as the classifier. The results are compared with those of the wavelet threshold-based method, another algorithm utilized for impulse and burst detection, which indicates that the ECFAR method gives an ameliorative classification result with an accuracy of 93% for different levels of leakage.

Integrated Sensor Fault Diagnosis and Fault-Tolerant Control for Manipulator

In this paper, an integrated scheme including fault diagnosis and fault-tolerant controller design is proposed for the manipulator system with the sensor fault. Any constant fault or time-varying fault can be estimated by the fault diagnosis scheme based on the adaptive observer rapidly and accurately, and the designed parameters can be solved by the linear matrix inequality. Using the fault estimation information, a fault-tolerant controller combining the characteristics of the proportional differentiation control and the sliding model control is designed to trace the expected trajectory via the back-stepping method. Finally, the effectiveness of the above scheme is verified by the simulation results.

Fault-Tolerant Resolvability and Extremal Structures of Graphs

In this paper, we consider fault-tolerant resolving sets in graphs. We characterize n-vertex graphs with fault-tolerant metric dimension n, n − 1 , and 2, which are the lower and upper extremal cases. Furthermore, in the first part of the paper, a method is presented to locate fault-tolerant resolving sets by using classical resolving sets in graphs. The second part of the paper applies the proposed method to three infinite families of regular graphs and locates certain fault-tolerant resolving sets. By accumulating the obtained results with some known results in the literature, we present certain lower and upper bounds on the fault-tolerant metric dimension of these families of graphs. As a byproduct, it is shown that these families of graphs preserve a constant fault-tolerant resolvability structure.

INTEGRATION OF IMPERFECT DEBUGGING IN GENERAL TESTING-DOMAIN DEPENDENT NHPP SRGM

Recently the general testing-domain dependent NHPP SRGM is developed to reflect repeated execution of constructs and location of detected faults. It assumes that debugging is perfect. Since realistic models need to reflect imperfect debugging, this paper integrates imperfect debugging in the general testing-domain dependent NHPP SRGM. Differential equations representing the mean value function are first derived for general testing strategy and then realized for the uniform testing. Specific mean value functions are obtained for some selected fault detection rate functions and constant fault reduction rate. Finally empirical performance evaluation is fulfilled.