505 research outputs found

    Self Care Among Filipino Immigrants in the United States Who Have Hypertension

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    Hypertension (HTN) is a leading risk factor in the development of cardiovascular disease (CVD) and stroke—two major causes of mortality and morbidity in the United States (US)—across all racial and ethnic groups, including Filipino immigrants. The results of early and recent studies that explored HTN among Filipinos in the US have consistently revealed a prevalence rate that is highest among Asian Americans. There is also evidence in the literature that indicates this population’s sub-optimal control and management of HTN when compared with other Asian American subgroups. Despite this reported alarming information about HTN for this population, there is a noticeable lack of studies on HTN among Filipinos in the US, especially those that explore the unique factors that might influence how this group experience and manage this chronic illness. The purpose of this study was to explore self-care among Filipino immigrants (n=163) who have HTN, and its relationship to acculturation, acculturative stress, HTN self-efficacy, and patient activation using the Transactional Model of Stress and Coping (TMSC) as a theoretical framework. The study results revealed that HTN self-efficacy (=0.27, t(116)=3.045, p=0.003) and patient activation (=0.21, t(116)=2.292, p=.024) significantly contributed to the regression model that accounted for 29.5% of the variance in HTN self-care for this sample. Further, a test of mediation on the role of patient activation in the relationship between HTN self-care and patient activation was conducted. The results of the bias corrected estimate of the indirect effect revealed that patient activation had a mediating role between HTN self efficacy and HTN self care (B=.15; CI95% = .0356, .3239) for this sample. Findings from this study highlight the importance of addressing HTN self efficacy and patient activation in improving HTN self care that would not only improve individual health outcomes but could also potentially reduce health inequity for this population

    Parameterized Model-Checking for Timed-Systems with Conjunctive Guards (Extended Version)

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    In this work we extend the Emerson and Kahlon's cutoff theorems for process skeletons with conjunctive guards to Parameterized Networks of Timed Automata, i.e. systems obtained by an \emph{apriori} unknown number of Timed Automata instantiated from a finite set U1,…,UnU_1, \dots, U_n of Timed Automata templates. In this way we aim at giving a tool to universally verify software systems where an unknown number of software components (i.e. processes) interact with continuous time temporal constraints. It is often the case, indeed, that distributed algorithms show an heterogeneous nature, combining dynamic aspects with real-time aspects. In the paper we will also show how to model check a protocol that uses special variables storing identifiers of the participating processes (i.e. PIDs) in Timed Automata with conjunctive guards. This is non-trivial, since solutions to the parameterized verification problem often relies on the processes to be symmetric, i.e. indistinguishable. On the other side, many popular distributed algorithms make use of PIDs and thus cannot directly apply those solutions

    Parameterized Verification of Systems with Global Synchronization and Guards

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    Inspired by distributed applications that use consensus or other agreement protocols for global coordination, we define a new computational model for parameterized systems that is based on a general global synchronization primitive and allows for global transition guards. Our model generalizes many existing models in the literature, including broadcast protocols and guarded protocols. We show that reachability properties are decidable for systems without guards, and give sufficient conditions under which they remain decidable in the presence of guards. Furthermore, we investigate cutoffs for reachability properties and provide sufficient conditions for small cutoffs in a number of cases that are inspired by our target applications.Comment: Accepted at CAV 202

    Word-level Symbolic Trajectory Evaluation

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    Symbolic trajectory evaluation (STE) is a model checking technique that has been successfully used to verify industrial designs. Existing implementations of STE, however, reason at the level of bits, allowing signals to take values in {0, 1, X}. This limits the amount of abstraction that can be achieved, and presents inherent limitations to scaling. The main contribution of this paper is to show how much more abstract lattices can be derived automatically from RTL descriptions, and how a model checker for the general theory of STE instantiated with such abstract lattices can be implemented in practice. This gives us the first practical word-level STE engine, called STEWord. Experiments on a set of designs similar to those used in industry show that STEWord scales better than word-level BMC and also bit-level STE.Comment: 19 pages, 3 figures, 2 tables, full version of paper in International Conference on Computer-Aided Verification (CAV) 201

    Complexity and Expressivity of Branching- and Alternating-Time Temporal Logics with Finitely Many Variables

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    We show that Branching-time temporal logics CTL and CTL*, as well as Alternating-time temporal logics ATL and ATL*, are as semantically expressive in the language with a single propositional variable as they are in the full language, i.e., with an unlimited supply of propositional variables. It follows that satisfiability for CTL, as well as for ATL, with a single variable is EXPTIME-complete, while satisfiability for CTL*, as well as for ATL*, with a single variable is 2EXPTIME-complete,--i.e., for these logics, the satisfiability for formulas with only one variable is as hard as satisfiability for arbitrary formulas.Comment: Prefinal version of the published pape

    Justness: A Completeness Criterion for Capturing Liveness Properties (Extended Abstract)

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    This paper poses that transition systems constitute a good model of distributed systems only in combination with a criterion telling which paths model complete runs of the represented systems. Among such criteria, progress is too weak to capture relevant liveness properties, and fairness is often too strong; for typical applications we advocate the intermediate criterion of justness. Previously, we proposed a definition of justness in terms of an asymmetric concurrency relation between transitions. Here we define such a concurrency relation for the transition systems associated to the process algebra CCS as well as its extensions with broadcast communication and signals, thereby making these process algebras suitable for capturing liveness properties requiring justness.Comment: An extended abstract of this paper appears in Proc. FoSSaCS'1

    Symmetric Strategy Improvement

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    Symmetry is inherent in the definition of most of the two-player zero-sum games, including parity, mean-payoff, and discounted-payoff games. It is therefore quite surprising that no symmetric analysis techniques for these games exist. We develop a novel symmetric strategy improvement algorithm where, in each iteration, the strategies of both players are improved simultaneously. We show that symmetric strategy improvement defies Friedmann's traps, which shook the belief in the potential of classic strategy improvement to be polynomial

    Computer aided synthesis: a game theoretic approach

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    In this invited contribution, we propose a comprehensive introduction to game theory applied in computer aided synthesis. In this context, we give some classical results on two-player zero-sum games and then on multi-player non zero-sum games. The simple case of one-player games is strongly related to automata theory on infinite words. All along the article, we focus on general approaches to solve the studied problems, and we provide several illustrative examples as well as intuitions on the proofs.Comment: Invitation contribution for conference "Developments in Language Theory" (DLT 2017

    Promptness and Bounded Fairness in Concurrent and Parameterized Systems

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    We investigate the satisfaction of specifications in Prompt Linear Temporal Logic (Prompt-LTL) by concurrent systems. Prompt-LTL is an extension of LTL that allows to specify parametric bounds onthe satisfaction of eventualities, thus adding a quantitative aspect to the specification language. We establish a connection between bounded fairness, bounded stutter equivalence, and the satisfaction of Prompt-LTL\X formulas. Based on this connection, we prove the first cutoff results for different classes of systems with a parametric number of components and quantitative specifications, thereby identifying previously unknown decidable fragments of the parameterized model checking problem

    Tight Cutoffs for Guarded Protocols with Fairness

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    Guarded protocols were introduced in a seminal paper by Emerson and Kahlon (2000), and describe systems of processes whose transitions are enabled or disabled depending on the existence of other processes in certain local states. We study parameterized model checking and synthesis of guarded protocols, both aiming at formal correctness arguments for systems with any number of processes. Cutoff results reduce reasoning about systems with an arbitrary number of processes to systems of a determined, fixed size. Our work stems from the observation that existing cutoff results for guarded protocols i) are restricted to closed systems, and ii) are of limited use for liveness properties because reductions do not preserve fairness. We close these gaps and obtain new cutoff results for open systems with liveness properties under fairness assumptions. Furthermore, we obtain cutoffs for the detection of global and local deadlocks, which are of paramount importance in synthesis. Finally, we prove tightness or asymptotic tightness for the new cutoffs.Comment: Accepted for publication at VMCAI 2016. Extended version, revised after conference review
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