International Nuclear Information System (INIS)

This paper deals with dynamic reliability of embedded systems. It presents a method for deriving feared scenarios (which might lead the system to a critical situation) in Petri nets. A classical way to obtain scenarios in Petri nets is to generate the reachability graph. However, for complex systems, it leads to the state space explosion. To avoid this problem, in our approach, Petri net reachability is translated into provability of linear logic sequents. Linear logic bases are introduced and used to formally define scenarios and minimality of scenarios. These definitions allow the method to produce only pertinent scenarios. The steps of the method are described and illustrated through a landing-gear system example.

CERN Document Server

In this report we focus on some aspects related to modeling and formal verification of embedded systems. Many models have been proposed to represent embedded systems . These models encompass a broad range of styles, characteristics, and application domains and include the extensions of finite state machines, data flow graphs, communication processes and Petri nets. In this report, we have used a PRES+ model (Petri net based Representation for Embedded Systems) as an extension of classical Petri net model that captures concurrency, timing behaviour of embedded systems; it allows systems to be representative in different levels of abstraction and improves expressiveness by allowing the token to carry information. Modeling using PRES+, as discussed above, may be convenient for specifying the input behaviour because it supports concurrency. However, there is no equivalence checking method reported in the literature for PRES+ ...

Science.gov (United States)

... ie on all paths from the root to a terminal node we ... (A) A stochastic Petri net ... Tandem Queueing Network [HMKS99] 63 26 19 173 2.297e4 7.148e ...

International Nuclear Information System (INIS)

Activation has been used for many kinds of useful applications, such as use of the radioisotopes for diagnosis and treatment of cancer, and wear (or corrosion) investigation for using thin layer activation (TLA) technique, etc. But activation also has severe problems for the post-processing of the samples; such as time-loss, inconvenience of sample handling, personal radiation safety, etc. For in-vitro experiments, we observed death of tumor cells by proton irradiation. The use of large activated container material can cause erroneous results in this case. To solve these problems, we studied why the samples were activated and how the level of the activation could be reduced. In proton beam irradiation experiments, the target materials could be defined as the container and sample itself. We could easily reduce activation of container material comparing to activation of sample itself. Therefore, we tried to find less activated container material by irradiating proton beam in PS ...