Non-null Infinitesimal Micro-steps: a Metric Temporal Logic Approach

Many systems include components interacting with each other that evolve with possibly very different speeds. To deal with this situation many formal models adopt the abstraction of "zero-time transitions", which do not consume time. These however have several drawbacks in terms of naturalness and logic consistency, as a system is modeled to be in different states at the same time. We propose a novel approach that exploits concepts from non-standard analysis to introduce a notion of micro- and macro-steps in an extension of the TRIO metric temporal logic, called X-TRIO. We use X-TRIO to provide a formal semantics and an automated verification technique to Stateflow-like notations used in the design of flexible manufacturing systems.Comment: 20 pages, 2 figures, submitted to the conference "FORMATS: Formal Modelling and Analysis of Timed Systems" 201

Small mammals at the Field Station

Ecological studies of small mammals are undertaken for a variety of reasons. Some investigations are conducted to determine their economic relationship to man, since small mammals directly affect his welfare through transmission of diseases and parasites and through destruction of crops, orchards, and forest seedlings. Much research, however, is basic in nature. The primary objectives of such research are to aid in man\u27s quest for knowledge concerning the distributional and population aspects of small mammals. During the summer of 1968, an intensive live-trapping program was begun to determine the status of small mammals, primarily mice and shrews, among the various habitats found at the Cedar-Sauk Field Station

Motives and Methods of Social Mobilization in Rural Senegal

Senegal, a predominantly Muslim West African country, has demonstrated political stability, sustained a constitutional democracy, and maintained a pluralistic society since independence in 1960. Amidst this, there are several small groups of social organizers who are engaging in effective social change. Tostan, a regional INGO focusing on community empowerment through nonformal education, has been working in Senegal for more than 25 years and has reached more than three million people in West Africa. After completing Tostan’s Community Empowerment Program (CEP), the social organizers have decided to travel from village to village educating and sensitizing others on what they have learned. Outside of West Africa, the rich experience of social mobilization and community organization in Senegal is hardly known among academics and social movement theorists. This research explores how and why Tostan’s Social Mobilization Agents (SMA) do their work in rural Senegal. Using a grounded theory approach rooted in feminist epistemology, I participated in field observations and conducted several in-depth interviews with six SMAs, two men and four women. By creating individual portraits of their lives, we see them as whole persons made up of unique experiences. After having a close up look at their lives, we take a step back to look at the larger picture and see several reoccurring themes. From this research, academics, practitioners, and a larger global audience will better understand the motives and methods of social mobilizers in rural Senegal today. With these findings, one can continue the quest for more knowledge and/or attempt to replicate the methods of social mobilization elsewhere

Asplenium Plenum: A Fern Which Suggests An Unusual Method Of Species Formation

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141431/1/ajb210734.pd

Bounded Reachability for Temporal Logic over Constraint Systems

We present CLTLB(D), an extension of PLTLB (PLTL with both past and future operators) augmented with atomic formulae built over a constraint system D. Even for decidable constraint systems, satisfiability and Model Checking problem of such logic can be undecidable. We introduce suitable restrictions and assumptions that are shown to make the satisfiability problem for the extended logic decidable. Moreover for a large class of constraint systems we propose an encoding that realize an effective decision procedure for the Bounded Reachability problem

Constraint LTL Satisfiability Checking without Automata

This paper introduces a novel technique to decide the satisfiability of formulae written in the language of Linear Temporal Logic with Both future and past operators and atomic formulae belonging to constraint system D (CLTLB(D) for short). The technique is based on the concept of bounded satisfiability, and hinges on an encoding of CLTLB(D) formulae into QF-EUD, the theory of quantifier-free equality and uninterpreted functions combined with D. Similarly to standard LTL, where bounded model-checking and SAT-solvers can be used as an alternative to automata-theoretic approaches to model-checking, our approach allows users to solve the satisfiability problem for CLTLB(D) formulae through SMT-solving techniques, rather than by checking the emptiness of the language of a suitable automaton A_{\phi}. The technique is effective, and it has been implemented in our Zot formal verification tool.Comment: 39 page

A Dual Language Approach Extension to UML for the Development of Time-Critical Component-Based Systems

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Formal Languages and Compilation

This textbook describes the essential principles and methods used for defining the syntax of artificial languages, and for designing efficient parsing algorithms and syntax-directed translators with semantic attributes. A comprehensive selection of topics is presented within a rigorous, unified framework, illustrated by numerous practical examples. Features and topics: presents a novel conceptual approach to parsing algorithms that applies to extended BNF grammars, together with a parallel parsing algorithm; supplies supplementary teaching tools, including course slides and exercises with solutions, at an associated website; unifies the concepts and notations used in different approaches, enabling an extended coverage of methods with a reduced number of definitions; systematically discusses ambiguous forms, allowing readers to avoid pitfalls when designing grammars; describes all algorithms in pseudocode, so that detailed knowledge of a specific programming language is not necessary; makes extensive usage of theoretical models of automata, transducers and formal grammars; includes concise coverage of algorithms for processing regular expressions and finite automata; and introduces static program analysis based on flow equations. This clearly-written, classroom-tested textbook is an ideal guide to the fundamentals of this field for advanced undergraduate and graduate students in computer science and computer engineering. Some background in programming is required, and readers should also be familiar with basic set theory, algebra and logic

A temporal logic for micro- and macro-step-based real-time systems: Foundations and applications

Many systems include components interacting with each other that evolve at possibly very different speeds. To deal with this situation many formal models adopt the abstraction of “zero-time transitions”, which do not consume time. These, however, have several drawbacks in terms of naturalness and logic consistency, as a system is modeled to be in different states at the same time. We propose a novel approach that exploits concepts from non-standard analysis and pairs them with the traditional “next” operator of temporal logic to introduce a notion of micro- and macro-steps; our approach is enacted in an extension of the TRIO metric temporal logic, called X-TRIO. We study the expressiveness and decidability properties of the new logic. Decidability is achieved through translation of a meaningful subset of X-TRIO into Linear Temporal Logic, a traditional way to support automated verification. We illustrate the usefulness and the generality of our approach by applying it to provide a formal semantics of timed Petri nets, which allows for their automated verification. We also give an overview of a formal semantics of Stateflow/Simulink diagrams, defined in terms of X-TRIO, which has been applied to the automated verification of a robotic cell