240 research outputs found
Trace checking of Metric Temporal Logic with Aggregating Modalities using MapReduce
Modern complex software systems produce a large amount of execution data,
often stored in logs. These logs can be analyzed using trace checking
techniques to check whether the system complies with its requirements
specifications. Often these specifications express quantitative properties of
the system, which include timing constraints as well as higher-level
constraints on the occurrences of significant events, expressed using aggregate
operators. In this paper we present an algorithm that exploits the MapReduce
programming model to check specifications expressed in a metric temporal logic
with aggregating modalities, over large execution traces. The algorithm
exploits the structure of the formula to parallelize the evaluation, with a
significant gain in time. We report on the assessment of the implementation -
based on the Hadoop framework - of the proposed algorithm and comment on its
scalability.Comment: 16 pages, 6 figures, Extended version of the SEFM 2014 pape
Efficient Large-scale Trace Checking Using MapReduce
The problem of checking a logged event trace against a temporal logic
specification arises in many practical cases. Unfortunately, known algorithms
for an expressive logic like MTL (Metric Temporal Logic) do not scale with
respect to two crucial dimensions: the length of the trace and the size of the
time interval for which logged events must be buffered to check satisfaction of
the specification. The former issue can be addressed by distributed and
parallel trace checking algorithms that can take advantage of modern cloud
computing and programming frameworks like MapReduce. Still, the latter issue
remains open with current state-of-the-art approaches.
In this paper we address this memory scalability issue by proposing a new
semantics for MTL, called lazy semantics. This semantics can evaluate temporal
formulae and boolean combinations of temporal-only formulae at any arbitrary
time instant. We prove that lazy semantics is more expressive than standard
point-based semantics and that it can be used as a basis for a correct
parametric decomposition of any MTL formula into an equivalent one with
smaller, bounded time intervals. We use lazy semantics to extend our previous
distributed trace checking algorithm for MTL. We evaluate the proposed
algorithm in terms of memory scalability and time/memory tradeoffs.Comment: 13 pages, 8 figure
Controlling the Frequency-Temperature Sensitivity of a Cryogenic Sapphire Maser Frequency Standard by Manipulating Fe3+ Spins in the Sapphire Lattice
To create a stable signal from a cryogenic sapphire maser frequency standard,
the frequency-temperature dependence of the supporting Whispering Gallery mode
must be annulled. We report the ability to control this dependence by
manipulating the paramagnetic susceptibility of Fe3+ ions in the sapphire
lattice. We show that the maser signal depends on other Whispering Gallery
modes tuned to the pump signal near 31 GHz, and the annulment point can be
controlled to exist between 5 to 10 K depending on the Fe3+ ion concentration
and the frequency of the pump. This level of control has not been achieved
previously, and will allow improvements in the stability of such devices.Comment: 17 pages, 10 figure
A New Zn(II) Metal Hybrid Material of 5-Nitrobenzimidazolium Organic Cation (C7H6N3O2)2[ZnCl4]: Elaboration, Structure, Hirshfeld Surface, Spectroscopic, Molecular Docking Analysis, Electric and Dielectric Properties
The slow solvent evaporation approach was used to create a single crystal of (CHNO)[ZnCl] at room temperature. Our compound has been investigated by single-crystal XRD which declares that the complex crystallizes in the monoclinic crystallographic system with the P2/c as a space group. The molecular arrangement of the compound can be described by slightly distorted tetrahedral ZnCl anionic entities and 5-nitrobenzimidazolium as cations, linked together by different non-covalent interaction types (H-bonds, Cl…Cl, π…π and C–H…π). Hirshfeld’s surface study allows us to identify that the dominant contacts in the crystal building are H…Cl/Cl…H contacts (37.3%). FT-IR method was used to identify the different groups in (CHNO)[ZnCl]. Furthermore, impedance spectroscopy analysis in 393 ≤ T ≤ 438 K shows that the temperature dependence of DC conductivity follows Arrhenius’ law. The frequency–temperature dependence of AC conductivity for the studied sample shows one region (E = 2.75 eV). In order to determine modes of interactions of compound with double stranded DNA, molecular docking simulations were performed at molecular level
Impact of biodiesel fuel on cold starting of automotive direct injection diesel engines
The use of biodiesel fuels in diesel engines is gaining attention as a promising solution to control CO2
emissions. Great research efforts have been carried out to identify the impact of biodiesel physical and
chemical properties on engine systems and processes. Most of these investigations were performed in
warm conditions, but the suitability of biodiesel for starting the engine at under-zero ambient temperatures
has not widely evaluated. The surface tension and the viscosity of biodiesel fuels are higher
compared to those of standard diesel and, in cold conditions, these differences become critical since the
injection fuel rate is largely affected and consequently the combustion process can be deteriorated. In
order to improve its flow characteristics at cold temperatures and make them more suitable for low
temperatures operation, additives are used in biodiesel fuels. In this paper the suitability of different
biodiesel fuels, with and without additives, for cold starting of DI (direct injection) diesel engines has
been evaluated. The results have shown that the engine start-ability with pure biodiesel fuels can be
largely deteriorated. However, using diesel/biodiesel blends the start-ability of the engine can be
recovered with the additional benefit of reducing the opacity peak of the exhaust gasesBroatch Jacobi, JA.; Tormos Martínez, BV.; Olmeda González, PC.; Novella Rosa, R. (2014). Impact of biodiesel fuel on cold starting of automotive direct injection diesel engines. Energy. 73:653-660. doi:10.1016/j.energy.2014.06.062S6536607
Ideas del alumnado de primaria y secundaria sobre aleatoriedad
En este trabajo comparamos las características de las secuencias de resultados
aleatorios y distribuciones aleatorias de puntos generadas por tres grupos de alumnos
de Educación Primaria y Secundaria con las propiedades matemáticas de las mismas.
La finalidad es describir el significado personal que dichos estudiantes asignan a la
aleatoriedad.In this paper we compare the features in random sequences and random distribution
of points produced by three groups of students in Primary and Secondary Education
with the mathematical properties of the same. The aim is to describe the meaning of
randomness for these students.Facultad de Educación y Humanidades - Campus de Melilla (Universidad de Granada)Este trabajo es parte de los proyectos SEJ2004-00789, Madrid, MCYT y FQM-126, Junta de Andalucí
Peak grain forecasts for the US High Plains amid withering waters
ACKNOWLEDGMENTS. This paper stems from discussions during the Ettersburg Ecohydrology Workshop in Germany (October 2018), with the corresponding manuscript preparation ensuing in subsequent months. The workshop was funded by the UNIDEL Foundation, Inc. and the University of Delaware. Accordingly, partial support for this paper derived from funding for the workshop. A.M. was supported by the US NSF (Grants NSF-AGS-1644382 and NSF-IOS-175489).Peer reviewedPublisher PD
Embryonic vitamin D deficiency programs hematopoietic stem cells to induce type 2 diabetes
Environmental factors may alter the fetal genome to cause metabolic diseases. It is unknown whether embryonic immune cell programming impacts the risk of type 2 diabetes in later life. We demonstrate that transplantation of fetal hematopoietic stem cells (HSCs) made vitamin D deficient in utero induce diabetes in vitamin D-sufficient mice. Vitamin D deficiency epigenetically suppresses Jarid2 expression and activates the Mef2/PGC1a pathway in HSCs, which persists in recipient bone marrow, resulting in adipose macrophage infiltration. These macrophages secrete miR106-5p, which promotes adipose insulin resistance by repressing PIK3 catalytic and regulatory subunits and down-regulating AKT signaling. Vitamin D-deficient monocytes from human cord blood have comparable Jarid2/Mef2/PGC1a expression changes and secrete miR-106b-5p, causing adipocyte insulin resistance. These findings suggest that vitamin D deficiency during development has epigenetic consequences impacting the systemic metabolic milieu
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