755 research outputs found
Multiplayer Cost Games with Simple Nash Equilibria
Multiplayer games with selfish agents naturally occur in the design of
distributed and embedded systems. As the goals of selfish agents are usually
neither equivalent nor antagonistic to each other, such games are non zero-sum
games. We study such games and show that a large class of these games,
including games where the individual objectives are mean- or discounted-payoff,
or quantitative reachability, and show that they do not only have a solution,
but a simple solution. We establish the existence of Nash equilibria that are
composed of k memoryless strategies for each agent in a setting with k agents,
one main and k-1 minor strategies. The main strategy describes what happens
when all agents comply, whereas the minor strategies ensure that all other
agents immediately start to co-operate against the agent who first deviates
from the plan. This simplicity is important, as rational agents are an
idealisation. Realistically, agents have to decide on their moves with very
limited resources, and complicated strategies that require exponential--or even
non-elementary--implementations cannot realistically be implemented. The
existence of simple strategies that we prove in this paper therefore holds a
promise of implementability.Comment: 23 page
SAT-Based Synthesis Methods for Safety Specs
Automatic synthesis of hardware components from declarative specifications is
an ambitious endeavor in computer aided design. Existing synthesis algorithms
are often implemented with Binary Decision Diagrams (BDDs), inheriting their
scalability limitations. Instead of BDDs, we propose several new methods to
synthesize finite-state systems from safety specifications using decision
procedures for the satisfiability of quantified and unquantified Boolean
formulas (SAT-, QBF- and EPR-solvers). The presented approaches are based on
computational learning, templates, or reduction to first-order logic. We also
present an efficient parallelization, and optimizations to utilize reachability
information and incremental solving. Finally, we compare all methods in an
extensive case study. Our new methods outperform BDDs and other existing work
on some classes of benchmarks, and our parallelization achieves a super-linear
speedup. This is an extended version of [5], featuring an additional appendix.Comment: Extended version of a paper at VMCAI'1
Effusion attenuates the effect of synovitis on radiographic progression in patients with hand osteoarthritis: a longitudinal magnetic resonance imaging study
An exploratory study to determine the role of effusion, i.e., fluid in the joint, in pain, and radiographic progression in patients with hand osteoarthritis. Distal and proximal interphalangeal joints (87 patients, 82% women, mean age 59 years) were assessed for pain. T2-weighted and Gd-chelate contrast-enhanced T1-weighted magnetic resonance images were scored for enhanced synovial thickening (EST, i.e., synovitis), effusion (EST and T2-high signal intensity [hsi]) and bone marrow lesions (BMLs). Effusion was defined as follows: (1) T2-hsi > 0 and EST = 0; or 2) T2-hsi = EST but in different joint locations. Baseline and 2-year follow-up radiographs were scored following Kellgren-Lawrence, increase >= 1 defined progression. Associations between the presence of effusion and pain and radiographic progression, taking into account EST and BML presence, were explored on the joint level. Effusion was present in 17% (120/691) of joints, with (63/120) and without (57/120) EST. Effusion on itself was not associated with pain or progression. The association with pain and progression, taking in account other known risk factors, was stronger in the absence of effusion (OR [95% CI] 1.7 [1.0-2.9] and 3.2 [1.7-5.8]) than in its presence (1.6 [0.8-3.0] and 1.3 [0.5-3.1]). Effusion can be assessed on MR images and seems not to be associated with pain or radiographic progression but attenuates the association between synovitis and progression.Clinical epidemiolog
Bone marrow lesions on magnetic resonance imaging in hand osteoarthritis are associated with pain and interact with synovitis
Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas
Incremental QBF Solving
We consider the problem of incrementally solving a sequence of quantified
Boolean formulae (QBF). Incremental solving aims at using information learned
from one formula in the process of solving the next formulae in the sequence.
Based on a general overview of the problem and related challenges, we present
an approach to incremental QBF solving which is application-independent and
hence applicable to QBF encodings of arbitrary problems. We implemented this
approach in our incremental search-based QBF solver DepQBF and report on
implementation details. Experimental results illustrate the potential benefits
of incremental solving in QBF-based workflows.Comment: revision (camera-ready, to appear in the proceedings of CP 2014,
LNCS, Springer
Fuel Conditions Associated with Native and Exotic Grasses in a Subtropical Dry Forest in Puerto Rico
Exotic grasses capable of increasing frequency and intensity of anthropogenic fire have invaded subtropical and tropical dry forests worldwide. Since many dry forest trees are susceptible to fire, this can result in decline of native species and loss of forest cover. While the contribution of exotic grasses to altered fire regimes has been well documented, the role of native grasses in contributing to fuel loads in dry forest has received little attention. We assessed differences in fuel conditions among native and exotic grasses within a subtropical dry forest preserve in Puerto Rico. We quantified fine fuel loads, fuel continuity, and seasonal changes in percent dead grass among the following grass patch types: (1) native grass with no known history of recent fire, (2) exotic grass that had burned once (single burn), and (3) exotic grass that burns frequently. Sampling was conducted during one wet season (August to October 2008) and again in the following dry season (February to March 2009). Overall, fine fuel loading was highest in native grass, but this was due to woody fuels rather than grass fuels. Percent of dead grass fuels increased with the transition from wet to dry season, and this increase was more pronounced for exotic grasses. Fuel continuity was highest in frequently burned exotic grass. Differences in grass phenology and fuel continuity may contribute to differences in fire frequency among native and exotic grass patches. Fuel management focused on prescribed fire should be used in conjunction with restoration of tree canopy to reduce fuels and limit development of a grass-fire cycle
Soil suppressiveness of Meloidogyne, Verticillium and Pythium in diverse agricultural soils: possible mechanisms, and options for sustainable management
Grond uit veertien verschillende glastuinbedrijven is door middel van biotoetsen getest op ziektewerend vermogen tegen drie belangrijke pathogenen, namelijk Meloidogyne incognita, Pythium aphanidermatum and Verticillium dahliae
Affordability influences nutritional quality of seafood consumption among income and race/ethnicity groups in the United States
Background
The 2020 US Dietary Guidelines for Americans recommend that the US population consume more seafood. Most analyses of seafood consumption ignore heterogeneity in consumption patterns by species, nutritional content, production methods, and price, which have implications for applying recommendations.
Objectives
We assessed seafood intake among adults by socioeconomic and demographic groups, as well as the cost of seafood at retail to identify affordable and nutritious options.
Methods
NHANES 2011–2018 dietary data (n = 17,559 total, n = 3285 eating seafood) were used to assess adult (≥20 y) intake of seafood in relation to income and race/ethnicity. Multivariable linear regression assessed the association between seafood consumption and income, adjusted for age, sex, and race/ethnicity, and the association between nutrients and seafood price, using Nielsen 2017–2019 retail sales data, adjusted for sales volume.
Results
Low-income groups consume slightly less seafood than high-income groups [low income: mean 120.2 (95% CI: 103.5, 137.2) g/wk; high income: 141.8 (119.1, 164.1) g/wk] but substantially less seafood that is high in long-chain n–3 (ω-3) PUFAs [lower income: 21.3 (17.3, 25.5) g/wk; higher income: 46.8 (35.4, 57.8) g/wk]. Intake rates, species, and production method choices varied by race/ethnicity groups and within race/ethnicity groups by income. Retail seafood as a whole costs more than other protein foods (e.g., meat, poultry, eggs, beans), and fresh seafood high in n–3 PUFAs costs more (P < 0.002) than fresh seafood low in n–3 PUFAs. Retail seafood is available in a wide range of price points and product forms, and some lower-cost fish and shellfish were high in n–3 PUFAs, calcium, iron, selenium, and vitamins B-12 and D.
Conclusions
New insights into the relation between seafood affordability and consumption patterns among income and ethnicity groups suggest that specific policies and interventions may be needed to enhance the consumption of seafood by different groups.publishedVersio
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