Erroneous Behavior Research Articles

Extensions of asynchronous circuits and the delay problem I. Good extensions and the delay problem of the first kind

Delays of signal propagation inherent in the wires interconnecting the logical elements of an asynchronous circuit sometimes cause erroneous behavior of the circuit. This problem is known as the delay problem, of which this paper attempts to make a full analysis from the broadest possible perspective. Basic to our theory is the concept of extensions. An extension C * of a circuit C is another circuit having hidden nodes in addition to the nodes of C. A requirement is introduced for C * to be “practically identical” to C, and conditions are derived for it to hold. A model of the delays within the wires is established, and the significance of the requirement relative to this model is investigated. For a fairly broad class of configurations of the wires, a finite procedure for checking whether the delays are harmful or not is given. Part of the mathematical framework of this paper is also applicable to a number of related problems other than the delay problem.

Silicon photovoltaic cells and the utilization of solar energy

Erroneous human behavior is often cited as a major factor to system failure. However, the complexity of the human-automation interaction can make it difficult for engineers to anticipate how erroneous human behavior can contribute to failures. In this work, we introduce a novel method for generating human errors based on the task-based taxonomy of erroneous human behavior. This allows erroneous acts to manifest as divergences from task models. We implement our method using the Enhanced Operator Function Model. We further show how the method can be used with formal system modeling and formal verification with model checking to prove whether or not potentially unanticipated erroneous behavior could contribute to system failures. We evaluate how our method scales and use it to evaluate three case studies: a radiation therapy machine, a pain medication pump, and an Apache helicopter. We discuss these results and explore options for future work.