2,423 research outputs found
Verifying Real-Time Systems using Explicit-time Description Methods
Timed model checking has been extensively researched in recent years. Many
new formalisms with time extensions and tools based on them have been
presented. On the other hand, Explicit-Time Description Methods aim to verify
real-time systems with general untimed model checkers. Lamport presented an
explicit-time description method using a clock-ticking process (Tick) to
simulate the passage of time together with a group of global variables for time
requirements. This paper proposes a new explicit-time description method with
no reliance on global variables. Instead, it uses rendezvous synchronization
steps between the Tick process and each system process to simulate time. This
new method achieves better modularity and facilitates usage of more complex
timing constraints. The two explicit-time description methods are implemented
in DIVINE, a well-known distributed-memory model checker. Preliminary
experiment results show that our new method, with better modularity, is
comparable to Lamport's method with respect to time and memory efficiency
From RT-LOTOS to Time Petri Nets new foundations for a verification platform
The formal description technique RT-LOTOS has been selected as intermediate language to add formality to a real-time UML profile named TURTLE. For this sake, an RT-LOTOS verification platform has been developed for early detection of design errors in real-time system models. The paper discusses an extension of the platform by inclusion of verification tools developed for Time Petri Nets. The starting point is the definition of RT-LOTOS to TPN translation patterns. In particular, we introduce the concept of components embedding Time Petri Nets. The translation patterns are implemented in a prototype tool which takes as input an RT-LOTOS specification and outputs a TPN in the format admitted by the TINA tool. The efficiency of the proposed solution has been demonstrated on various case studies
Timed Automaton Models for Simple Programmable Logic Controllers
We give timed automaton models for a class of Programmable Logic Controller (PLC) applications, that are programmed in a simple fragment of the language Instruction Lists as defined in the standard IEC 1131-3. Two different approaches for modelling timers are suggested, that lead to two different timed automaton models. The purpose of this work is to provide a basis for verification and testing of real-time properties of PLC applications. Our work can be seen in broader context: it is a contribution to methodical development of provably correct programs. Even if the present PLC hardware will be substituted by e.g. Personal Computers, with a similar operation mode, the development and verification method will remain useful
Specification Patterns for Robotic Missions
Mobile and general-purpose robots increasingly support our everyday life,
requiring dependable robotics control software. Creating such software mainly
amounts to implementing their complex behaviors known as missions. Recognizing
the need, a large number of domain-specific specification languages has been
proposed. These, in addition to traditional logical languages, allow the use of
formally specified missions for synthesis, verification, simulation, or guiding
the implementation. For instance, the logical language LTL is commonly used by
experts to specify missions, as an input for planners, which synthesize the
behavior a robot should have. Unfortunately, domain-specific languages are
usually tied to specific robot models, while logical languages such as LTL are
difficult to use by non-experts. We present a catalog of 22 mission
specification patterns for mobile robots, together with tooling for
instantiating, composing, and compiling the patterns to create mission
specifications. The patterns provide solutions for recurrent specification
problems, each of which detailing the usage intent, known uses, relationships
to other patterns, and---most importantly---a template mission specification in
temporal logic. Our tooling produces specifications expressed in the LTL and
CTL temporal logics to be used by planners, simulators, or model checkers. The
patterns originate from 245 realistic textual mission requirements extracted
from the robotics literature, and they are evaluated upon a total of 441
real-world mission requirements and 1251 mission specifications. Five of these
reflect scenarios we defined with two well-known industrial partners developing
human-size robots. We validated our patterns' correctness with simulators and
two real robots
Rapid Development of Morphological Descriptions for Full Language Processing Systems
I describe a compiler and development environment for feature-augmented
two-level morphology rules integrated into a full NLP system. The compiler is
optimized for a class of languages including many or most European ones, and
for rapid development and debugging of descriptions of new languages. The key
design decision is to compose morphophonological and morphosyntactic
information, but not the lexicon, when compiling the description. This results
in typical compilation times of about a minute, and has allowed a reasonably
full, feature-based description of French inflectional morphology to be
developed in about a month by a linguist new to the system.Comment: 8 pages, LaTeX (2.09 preferred); eaclap.sty; Procs of Euro ACL-9
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