Perfect failure detectors can correctly decide whether a computer is crashed. However, it is impossible to implement a perfect failure detector in purely asynchronous systems. We show how to enforce perfect failure detection in timed asynchronous systems with hardware watchdogs. The two main system model assumptions are (1) each computer can measure time intervals with a known maximum error, an...

Plan execution monitoring in dynamic and uncertain domains is an important and difficult problem. Multi-agent environments exacerbate this problem, given that interacting and coordinated activities of multiple agents are to be monitored. Previous approaches to this problem do not detect certain classes of failures, are inflexible, and are hard to scale up. We present a novel approach, SOCFAD, t...

Byzantine failure detectors provide an elegant abstraction for implementing Byzantine fault tolerance. However, as far as we know, there is no general solution for this problem in a dynamic distributed system over wireless networks with unknown membership. This paper presents thus a rst Byzantine failure detector for this context. The protocol has the interesting feature to be time-free, that i...

Today software systems are playing a critical role in the operation of telecommunication networks. The steadly growing size and complexity of these systems are making them extremely difficulty to exaustively test the software to ensure that it will adequately perform its specified function. With the increasing reliance on software systems for implementation of telecom service functionality, the...

This paper addresses the localization of anatomical structures in medical images by a Generalized Hough Transform (GHT). As localization is often a pre-requisite for subsequent model-based segmentation, it is important to assess whether or not the GHT was able to locate the desired object. The GHT by its construction does not make this distinction. We present an approach to detect incorrect GHT...

Most face applications depend heavily on the accuracy of the face and facial landmarks detectors employed. Prediction of attributes such as gender, age, and identity usually completely fail when the faces are badly aligned due to inaccurate facial landmark detection. Despite the impressive recent advances in face and facial landmark detection, little study is on the recovery from and detection ...

With the current default settings of the OSPF parameters, the network takes several tens of seconds before recovering from a failure. The main component in this delay is the time required to detect the failure using Hello protocol. Failure detection time can be speeded up by reducing the value of HelloInterval. However, too small a value of HelloInterval will result in an increased chance of ne...

Future unmanned space missions will require increased redundancy to failure. One such mission is the Mars Sample Return, intended to return a sample of Martian soil, rock and atmosphere to Earth for greater study. A key element of the Mars Sample Return mission is the Mars Ascent Vehicle, which is designed to carry the sample container from the surface into Mars orbit, where the sample will be ...

With the rise of enhanced GNSS services over the next decade (i.e. the modernized GPS, Galileo, GLONASS, and Compass constellations), the number of ranging sources (satellites) available for a positioning will significantly increase to more than double the current value. One can no longer assume that the probability of failure for more than one satellite within a certain timeframe is negligible...

Debugging is notoriously difficult and extremely time consuming but also essential for ensuring the reliability and quality of a software system. In order to reduce debugging effort and enable automated failure detection, we propose an automated testing framework for detecting failures in cognitive agent programs. Our approach is based on the assumption that modules within such programs are a n...