title: A Framework for Compositional Synthesis of Modular Nonblocking Supervisors

authors: Mohajerani, Sahar

subjects: Science & Technology

abstract: This paper describes a framework for compositional supervisor synthesis, which is applicable to all discrete event systems modeled as a set of deterministic automata. Compositional synthesis exploits the modular structure of the input model, and therefore works best for models consisting of a large number of small automata. The state-space explosion is mitigated by the use of abstraction to simplify individual components, and the property of synthesis equivalence guarantees that the final synthesis result is the same as it would have been for the non-abstracted model. The paper describes synthesis equivalent abstractions and shows their use in an algorithm to efficiently compute supervisors. The algorithm has been implemented in the DES software tool Supremica and successfully computes nonblocking modular supervisors, even for systems with more than 1014 reachable states, in less than 30 seconds.

text: A Framework for Compositional Synthesis of Modular Nonblocking Supervisors This paper describes a framework for compositional supervisor synthesis, which is applicable to all discrete event systems modeled as a set of deterministic automata. Compositional synthesis exploits the modular structure of the input model, and therefore works best for models consisting of a large number of small automata. The state-space explosion is mitigated by the use of abstraction to simplify individual components, and the property of synthesis equivalence guarantees that the final synthesis result is the same as it would have been for the non-abstracted model. The paper describes synthesis equivalent abstractions and shows their use in an algorithm to efficiently compute supervisors. The algorithm has been implemented in the DES software tool Supremica and successfully computes nonblocking modular supervisors, even for systems with more than 1014 reachable states, in less than 30 seconds.

year: 2014

title: Acoustic tamper detection sensor with very low false alarm rate

authors: Muijlwijk, Lawrence

subjects: false alarms

abstract: We describe a device designed to detect interference (vandalism or tampering) by acoustic means. The design employs both a piezoelectric vibration transducer and a common microphone in a novel mechanical arrangement. In contrast to conventional acoustic sensors that simply respond to vibrations above a threshold, this design analyses the outputs of the two to trigger an alarm. The method confers a near-zero susceptibility to triggering by external loud noises. No complex calculations are required so that only a low-cost, embedded microcontroller is required and the whole sensor can be very cheap. Extreme sensitivity can be achieved with little risk of false alarms.

text: Acoustic tamper detection sensor with very low false alarm rate We describe a device designed to detect interference (vandalism or tampering) by acoustic means. The design employs both a piezoelectric vibration transducer and a common microphone in a novel mechanical arrangement. In contrast to conventional acoustic sensors that simply respond to vibrations above a threshold, this design analyses the outputs of the two to trigger an alarm. The method confers a near-zero susceptibility to triggering by external loud noises. No complex calculations are required so that only a low-cost, embedded microcontroller is required and the whole sensor can be very cheap. Extreme sensitivity can be achieved with little risk of false alarms.

year: 2008

title: Putting the draft learning progression framework - Maori in the New Zealand Curriculum - to work: An Illustration

authors: Johnson, Diane

subjects: Māori language education

abstract: How language curricula are implemented in the classroom is of critical importance. Here, we take one achievement objective from the draft Learning Progression Framework for Māori in mainstream classes and demonstrate one way in which it can be realised as a core integrated skills lesson, that is, as a lesson that introduces new language (core lesson) through all four skills - reading, writing, listening and speaking (an integrated skills lesson). The lesson is preceded by a discussion of the type of planning that accompanies the implementation of language curricula.

text: Putting the draft learning progression framework - Maori in the New Zealand Curriculum - to work: An Illustration How language curricula are implemented in the classroom is of critical importance. Here, we take one achievement objective from the draft Learning Progression Framework for Māori in mainstream classes and demonstrate one way in which it can be realised as a core integrated skills lesson, that is, as a lesson that introduces new language (core lesson) through all four skills - reading, writing, listening and speaking (an integrated skills lesson). The lesson is preceded by a discussion of the type of planning that accompanies the implementation of language curricula.

year: 2003-09