2,219 research outputs found

    Reactive Turing Machines

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    We propose reactive Turing machines (RTMs), extending classical Turing machines with a process-theoretical notion of interaction, and use it to define a notion of executable transition system. We show that every computable transition system with a bounded branching degree is simulated modulo divergence-preserving branching bisimilarity by an RTM, and that every effective transition system is simulated modulo the variant of branching bisimilarity that does not require divergence preservation. We conclude from these results that the parallel composition of (communicating) RTMs can be simulated by a single RTM. We prove that there exist universal RTMs modulo branching bisimilarity, but these essentially employ divergence to be able to simulate an RTM of arbitrary branching degree. We also prove that modulo divergence-preserving branching bisimilarity there are RTMs that are universal up to their own branching degree. Finally, we establish a correspondence between executability and finite definability in a simple process calculus

    MARL-iDR: Multi-Agent Reinforcement Learning for Incentive-based Residential Demand Response

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    This paper presents a decentralized Multi-Agent Reinforcement Learning (MARL) approach to an incentive-based Demand Response (DR) program, which aims to maintain the capacity limits of the electricity grid and prevent grid congestion by financially incentivizing residential consumers to reduce their energy consumption. The proposed approach addresses the key challenge of coordinating heterogeneous preferences and requirements from multiple participants while preserving their privacy and minimizing financial costs for the aggregator. The participant agents use a novel Disjunctively Constrained Knapsack Problem optimization to curtail or shift the requested household appliances based on the selected demand reduction. Through case studies with electricity data from 2525 households, the proposed approach effectively reduced energy consumption's Peak-to-Average ratio (PAR) by 14.4814.48% compared to the original PAR while fully preserving participant privacy. This approach has the potential to significantly improve the efficiency and reliability of the electricity grid, making it an important contribution to the management of renewable energy resources and the growing electricity demand.Comment: 8 pages, IEEE Belgrade PowerTech, 202

    Experimental Tests of Free-Volume Tracer Diffusion in Water and Other Solvents

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    Using forced Rayleigh scattering, the tracer diffusion of methyl red through water and eight other solvents at different temperatures is investigated and the results are compared to the Cohen-Turnbull theory of free-volume diffusion. In seven solvents the effective non-Arrhenius activation energy measured experimentally agrees with the Cohen-Turnbull energy. In water, however, the diffusion can be described mathematically by the free volume model but there is a disagreement of more than an order of magnitude between these energies. We propose that the unique zero point free volume forced onto water by the strong hydrogen bonding requires a different mechanism for tracer motion

    Identification of TUB as a novel candidate gene influencing body weight in humans

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    Previously, we identified a locus on 11p influencing obesity in families with type 2 diabetes. Based on mouse studies, we selected TUB as a functional candidate gene and performed association studies to determine whether this controls obesity. We analyzed the genotypes of 13 single nucleotide polymorphisms (SNPs) around TUB in 492 unrelated type 2 diabetic patients with known BMI values. One SNP (rs1528133) was found to have a significant effect on BMI (1.54 kg/m(2), P = 0.006). This association was confirmed in a population enriched for type 2 diabetes, using 750 individuals who were not selected for type 2 diabetes. Two SNPs in linkage disequilibrium with rs1528133 and mapping to the 3' end of TUB, rs2272382, and rs2272383 also affected BMI by 1.3 kg/m2 (P = 0.016 and P = 0.010, respectively). Combined analysis confirmed this association (P = 0.005 and P = 0.002, respectively). Moreover, comparing 349 obese subjects (BMI >30 kg/m(2)) from the combined cohort with 289 normal subjects (BMI <25 kg/m(2)) revealed that the protective alleles have a lower frequency in obese subjects (odds ratio 1.32 [95% CI 1.04-1.67], P = 0.022). Altogether, data from the tubby mouse as well as these data suggest that TUB could be an important factor in controlling the central regulation of body weight in humans

    Depressive symptoms and risk of Alzheimer's disease in more highly educated older people

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    In an earlier study we observed that a depressive syndrome was highly predictive of developing Alzheimer's disease (AD) in older persons with normal baseline cognition and higher levels of education. We interpreted these findings as the depression being an early noncognitive manifestation of AD in persons with more cognitive reserve. The present study examines whether specific symptoms of depression can be identified that predict AD among older subjects with higher levels of education. In the community-based Amsterdam Study of the Elderly (AMSTEL), a sample of 3,147 nondemented persons with normal cognition, 65 to 84 years old, was selected and divided into subjects with >8 years and 8 years and 31 with 8 years of education depressed mood and subjective bradyphrenia were strongly associated with incident AD. No association between depressive symptoms and AD was observed among subjects with <or =8 years of education. Both depressed mood and subjective bradyphrenia seem to indicate subclinical AD in older people with higher levels of education. Clinicians should be alert that in these persons, AD may become apparent within a relatively short period of tim

    The transrectus sheath preperitoneal mesh repair for inguinal hernia: technique, rationale, and results of the first 50 cases

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    Item does not contain fulltextINTRODUCTION: Laparoscopic and endoscopic hernia repair popularized the preperitoneal mesh position due to promising results concerning less chronic pain. However, considerable proportions of severe adverse events, learning curves, or added costs have to be taken into account. Therefore, open preperitoneal mesh techniques may have more advantages. The open approach to the preperitoneal space (PPS) according to transrectus sheath preperitoneal (TREPP) mesh repair is through the sheath of the rectus abdominus muscle. This technique provides an excellent view of the PPS and facilitates elective or acute hernia reduction and mesh positioning under direct vision. In concordance with the promising transinguinal preperitoneal inguinal hernia repair experiences in the literature, we investigated the feasibility of TREPP. METHODS: A rationale description of the surgical technique, available level of evidence for thoughts behind technical considerations. Furthermore, a descriptive report of the clinical outcomes of our pilot case series including 50 patients undergoing the TREPP mesh repair. RESULTS: A consecutive group of our first 50 patients were operated with the TREPP technique. No technical problems were experienced during the development of this technique. No conversions to Lichtenstein repair were necessary. No recurrences and no chronic pain after a mean follow-up of 2 years were notable findings. CONCLUSION: This description of the technique shows that the TREPP mesh repair might be a promising method because of the complete preperitoneal view, the short learning curve, and the stay-away-from-the-nerves principle. The rationale of the TREPP repair is discussed in detail.1 juni 201

    Awareness of Risk Factors for Loneliness among Third Agers

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    Abstract Awareness of risk factors for loneliness is a prerequisite for preventive action. Many risk factors for loneliness have been identified. This paper focuses on two: poor health and widowhood. Preventive action by developing a satisfying social network requires time and effort and thus seems appropriate for people unexposed to risk factors, i.e. third agers and non-lonely persons. The third age is the period in old age after retirement, before people&apos;s social relationships deteriorate. Three questions are addressed. Are older adults aware of poor health and widowhood as risk factors for loneliness? Are there differences in awareness between third and fourth agers? Are there differences in awareness between lonely and non-lonely older adults? After being introduced to four vignette persons, 920 respondents from the Longitudinal Aging Study Amsterdam were asked whether they expected these persons to be lonely. Older adults, especially third agers, expected peers exposed to the risk factors to be lonely more often than peers who were unexposed. The results indicate that awareness of loneliness-provoking factors is high among third agers, which is a first step towards taking actions to avoid loneliness. Compared to lonely older adults, non-lonely ones expected peers to be lonely less often, suggesting the latter&apos;s lower awareness of the risk factors. The results might remind policymakers and practitioners that combating loneliness might require early action

    Expressiveness modulo Bisimilarity of Regular Expressions with Parallel Composition (Extended Abstract)

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    The languages accepted by finite automata are precisely the languages denoted by regular expressions. In contrast, finite automata may exhibit behaviours that cannot be described by regular expressions up to bisimilarity. In this paper, we consider extensions of the theory of regular expressions with various forms of parallel composition and study the effect on expressiveness. First we prove that adding pure interleaving to the theory of regular expressions strictly increases its expressiveness up to bisimilarity. Then, we prove that replacing the operation for pure interleaving by ACP-style parallel composition gives a further increase in expressiveness. Finally, we prove that the theory of regular expressions with ACP-style parallel composition and encapsulation is expressive enough to express all finite automata up to bisimilarity. Our results extend the expressiveness results obtained by Bergstra, Bethke and Ponse for process algebras with (the binary variant of) Kleene's star operation.Comment: In Proceedings EXPRESS'10, arXiv:1011.601
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