ASMs have been used at Siemens Corporate Technology to design a component in a software package called FALKO. Main purpose of FALKO is the construction and validation of timetables for railway systems. For simulation the whole closed-loop traffic control system is modelled within FALKO. The railway process model part of FALKO was formally specified using the ASM approach. C++ code is generated ...

We present a formal connection between supervisory control theory in the field of control engineering and reactive synthesis in the field of formal methods. We focus on the case of fully-observed discrete-event systems that are controlled by a single controller/supervisor in order to achieve a safety specification and a non-blocking specification. The connection is shown by a reduction of the c...

In this paper we describe a novel decentralized control strategy to realize formations of mobile robots. We first describe how to design artificial potential fields to obtain a formation with the shape of a regular polygon. We provide a formal proof of the asymptotic stability of the system, based on the definition of a proper Lyapunov function. We also prove that our control strategy is not af...

We give a formal specification of a new model called Network Membership for reliable mobile communication in asynchronous distributed systems. Our approach is new in the sense that the Network Membership service does not have any join or leave procedures. We let the system flow, views are not forced and are installed with stability. The model is less restrictive than others since no consensus i...

Autonomous space vehicles need adaptive control strategies that can accommodate unanticipated environmental conditions. The evaluation of new strategies can often be done only by actually trying them out in the real physical environment. Consequently, a candidate control strategy must be deemed safe—i.e., it won’t damage any systems— prior to being tested online. How to do this efficiently has ...

This paper develops a hierarchical control architecture for so called sequential behaviours, i.e. for plant dynamics and specifications that are represented as formal languages of infinite-length words. Our main result is the elaboration of structural properties that (a) allow for abstraction based controller design and that (b) are preserved under closed-loop composition. Thus, we propose to a...

Subjects and Methods: Four sequence variants are compared that differ only in the way the tag or control pulses are applied (see table). These four techniques were implemented on a Siemens Trio with an EPI-readout. Label and control mechanisms were simulated, varying all relevant parameters to optimize sequence settings of all measurements. In addition, the simulation results were used to estim...

Diverse programming is a recommended approach in the preparation of logic used to drive railway control systems, whereby different representations and processes are used to configure and validate the logic. This paper describes how two formal specifications have been used for the construction of a precise model of the logic, alternative to those represented using the user and machine notations,...

For automotive manufacturers and tier-1 suppliers, the upcoming safety standard ISO 26262 results in new requirements for the development of embedded electronics and software. In particular, the variety of driver assistance systems that autonomously influence the driving dynamics of a vehicle may have a high risk potential and require development in accordance with the normative guidelines. But...

Existing software infrastructures and middleware provide uniform security services across heterogeneous information networks. However, few, if any, tools exist that support access control policy management for and between large enterprise information networks. Insiders often exploit gaps in policies to mount devastating attacks. This paper presents a Policy Machine and Policy Mediation Architec...