238 research outputs found

    The manual work space of the upper extremity amputee /

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    Diagnose différentielle de l'espèce sur les carcasses et les abats des moutons et des chèvres de l'Afrique tropicale de l'Ouest

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    Les auteurs étudient région par région, les caractères immédiats et médiats de la diagnose d'espèce des carcasses et des abats des petits ruminants de l'Afrique de l'Ouest. Ils montrent que la diagnose est facile lorsque la tête et la queue restent sur la carcasse ou la demi-carcasse et qu'elle est difficile lorsqu'elles en sont séparées. Ils distinguent trois types de caractères différentiels: ceux qui sont communs aux deux groupes régionaux, ceux qui sont particuliers aux espèces des régions tempérées et ceux qui sont propres aux ovins et aux caprins de l'Afrique de l'Oues

    On Teaching Applied Formal Methods in Aerospace Engineering

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    As formal methods come into broad industrial use for verification of safety-critical hardware, software, and cyber-physical systems, there is an increasing need to teach practical skills in applying formal methods at both the undergraduate and graduate levels. In the aerospace industry, flight certification requirements like the FAA’s DO-178B, DO-178C, DO-333, and DO-254, along with a series of high-profile accidents, have helped turn knowledge of formal methods into a desirable job skill for a wide range of engineering positions. We approach the question of verification from a safety-case perspective: the primary teaching goal is to impart students with the ability to look at a verification question and identify what formal methods are applicable, which tools are available, what the outputs from those tools will say about the system, and what they will not, e.g., what parts of the safety case need to be provided by other means. We overview the lectures, exercises, exams, and student projects in a mixed-level (undergraduate/graduate) Applied Formal Methods course (Additional materials are available on the course website: http://temporallogic.org/courses/AppliedFormalMethods/) taught in an Aerospace Engineering department. We highlight the approach, tools, and techniques aimed at imparting a good sense of both the state of the art and the state of the practice of formal methods in an effort to effectively prepare students headed for jobs in an increasingly formal world

    Specification: The Biggest Bottleneck in Formal Methods and Autonomy

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    Advancement of AI-enhanced control in autonomous systems stands on the shoulders of formal methods, which make possible the rigorous safety analysis autonomous systems require. An aircraft cannot operate autonomously unless it has design-time reasoning to ensure correct operation of the autopilot and runtime reasoning to ensure system health management, or the ability to detect and respond to off-nominal situations. Formal methods are highly dependent on the specifications over which they reason; there is no escaping the “garbage in, garbage out” reality. Specification is difficult, unglamorous, and arguably the biggest bottleneck facing verification and validation of aerospace, and other, autonomous systems. This VSTTE invited talk and paper examines the outlook for the practice of formal specification, and highlights the on-going challenges of specification, from design-time to runtime system health management. We exemplify these challenges for specifications in Linear Temporal Logic (LTL) though the focus is not limited to that specification language. We pose challenge questions for specification that will shape both the future of formal methods, and our ability to more automatically verify and validate autonomous systems of greater variety and scale. We call for further research into LTL Genesis

    SAT-based Explicit LTL Reasoning

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    We present here a new explicit reasoning framework for linear temporal logic (LTL), which is built on top of propositional satisfiability (SAT) solving. As a proof-of-concept of this framework, we describe a new LTL satisfiability tool, Aalta\_v2.0, which is built on top of the MiniSAT SAT solver. We test the effectiveness of this approach by demonnstrating that Aalta\_v2.0 significantly outperforms all existing LTL satisfiability solvers. Furthermore, we show that the framework can be extended from propositional LTL to assertional LTL (where we allow theory atoms), by replacing MiniSAT with the Z3 SMT solver, and demonstrating that this can yield an exponential improvement in performance

    Osteoporosis drug treatment: duration and management after discontinuation. A position statement from the SVGO/ASCO.

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    Antiosteoporotic drugs are recommended in patients with fragility fractures and in patients considered to be at high fracture risk on the basis of clinical risk factors and/or low bone mineral density. As first-line treatment most patients are started with an antiresorptive treatment, i.e. drugs that inhibit osteoclast development and/or function (bisphosphonates, denosumab, oestrogens or selective oestrogen receptor modulators). In the balance between benefits and risks of antiresorptive treatment, uncertainties remain regarding the optimal treatment duration and the management of patients after drug discontinuation. Based on the available evidence, this position statement will focus on the long-term management of osteoporosis therapy, formulating decision criteria for clinical practice

    Influence of Caregivers and Children's Entry Into the Dental Care System

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    Early preventive dental visits are essential in improving children’s oral health, especially young children at high risk for dental caries. However, there is scant information on how these children enter the dental care system. Our objectives were as follows: (1) to describe how a population-based cohort of young Medicaid-enrolled children entered dental care; and (2) to investigate the influence of caregiver characteristics on their children’s dental care–seeking patterns

    More Scalable LTL Model Checking via Discovering Design-Space Dependencies (D3)

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    Modern system design often requires comparing several models over a large design space. Different models arise out of a need to weigh different design choices, to check core capabilities of versions with varying features, or to analyze a future version against previous ones. Model checking can compare different models; however, applying model checking off-the-shelf may not scale due to the large size of the design space for today’s complex systems. We exploit relationships between different models of the same (or related) systems to optimize the model-checking search. Our algorithm, D3 , preprocesses the design space and checks fewer model-checking instances, e.g., using nuXmv. It automatically prunes the search space by reducing both the number of models to check, and the number of LTL properties that need to be checked for each model in order to provide the complete model-checking verdict for every individual model-property pair. We formalize heuristics that improve the performance of D3 . We demonstrate the scalability of D3 by extensive experimental evaluation, e.g., by checking 1,620 real-life models for NASA’s NextGen air traffic control system. Compared to checking each model-property pair individually, D3 is up to 9.4 × faster
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