1,356 research outputs found
On the Behaviour of General-Purpose Applications on Cloud Storages
Managing data over cloud infrastructures raises novel challenges with respect to existing and well studied approaches such as ACID and long running transactions. One of the main requirements is to provide availability and partition tolerance in a scenario with replicas and distributed control. This comes at the price of a weaker consistency, usually called eventual consistency. These weak memory models have proved to be suitable in a number of scenarios, such as the analysis of large data with Map-Reduce. However, due to the widespread availability of cloud infrastructures, weak storages are used not only by specialised applications but also by general purpose applications. We provide a formal approach, based on process calculi, to reason about the behaviour of programs that rely on cloud stores. For instance, one can check that the composition of a process with a cloud store ensures `strong' properties through a wise usage of asynchronous message-passing
Diversity and distribution of jumping plant-lice (Hemiptera: Psylloidea) along edges of Amazon - Cerrado transitional forests in Sorriso, Mato Grosso, Brazil.
Little is known about the jumping plant-lice of Brazil from where seven families, 45 genera and 76 species have been previously reported, but estimates suggest that there may be as many as 1,000 species. This study reports 34 species of Psylloidea which were collected along the edges of Amazon?Cerrado natural transitional forests in the municipality of Sorriso, state of Mato Grosso, from August 2013 to July 2014. Of the species reported in this study only nine represent described taxa, two of which are reported for the first time from Mato Grosso.hardt et al. 2013; Mazzardo 2014; Mazzardo et al. 2016): the two introduced eucalypt pests Blastopsylla occidentalis and Glycaspis brimblecombei, the three Fabaceae feeders Euphalerus clitoriae, Isogonoceraia divergipennis and Macrocorsa beeryi, the Toona pest Mastigimas anjosi, and the Nectandra psylloid Limataphalara lautereri. To improve the apparent lack of knowledge, a survey of the psylloid fauna of the edges of Amazon?Cerrado native transitional forests was conducted in Sorriso, Mato Grosso, Brazil. Here we present a commented inventory of the species encountered during the dry and rainy seasons
Locality and Singularity for Store-Atomic Memory Models
Robustness is a correctness notion for concurrent programs running under
relaxed consistency models. The task is to check that the relaxed behavior
coincides (up to traces) with sequential consistency (SC). Although
computationally simple on paper (robustness has been shown to be
PSPACE-complete for TSO, PGAS, and Power), building a practical robustness
checker remains a challenge. The problem is that the various relaxations lead
to a dramatic number of computations, only few of which violate robustness.
In the present paper, we set out to reduce the search space for robustness
checkers. We focus on store-atomic consistency models and establish two
completeness results. The first result, called locality, states that a
non-robust program always contains a violating computation where only one
thread delays commands. The second result, called singularity, is even stronger
but restricted to programs without lightweight fences. It states that there is
a violating computation where a single store is delayed.
As an application of the results, we derive a linear-size source-to-source
translation of robustness to SC-reachability. It applies to general programs,
regardless of the data domain and potentially with an unbounded number of
threads and with unbounded buffers. We have implemented the translation and
verified, for the first time, PGAS algorithms in a fully automated fashion. For
TSO, our analysis outperforms existing tools
New country, Brazilian states and host records of the eucalypt shoot psyllid Blastopsylla occidentalis.
O psilÃdeo das ponteiras do eucalipto, Blastopsylla occidentalis Taylor, 1985 (Hemiptera: Psylloidea) é relatado aqui pela primeira vez para o Burundi, Indonésia (Sumatra), Nicarágua, Filipinas e Iêmen. O registro desta para o Paraguai mostrou ser um erro. Novos registros são dados para os estados brasileiros Bahia, Ceará, Piauà e Rio Grande do Sul. Eucalyptus viminalis é listado pela primeira vez como hospedeiro de B. occidentalis.Nota cientÃfica
Faster linearizability checking via -compositionality
Linearizability is a well-established consistency and correctness criterion
for concurrent data types. An important feature of linearizability is Herlihy
and Wing's locality principle, which says that a concurrent system is
linearizable if and only if all of its constituent parts (so-called objects)
are linearizable. This paper presents -compositionality, which generalizes
the idea behind the locality principle to operations on the same concurrent
data type. We implement -compositionality in a novel linearizability
checker. Our experiments with over nine implementations of concurrent sets,
including Intel's TBB library, show that our linearizability checker is one
order of magnitude faster and/or more space efficient than the state-of-the-art
algorithm.Comment: 15 pages, 2 figure
Occurrence of Russelliana solanicola Tuthill, 1959 (Hemiptera: Psyllidae), potencial vector of 'Candidatus Liberibacter solanacearum' on carrot crops.
Redescription of the little-known psyllid Cacopsylla dissimilis (Baeva, 1963) comb. nov. (Hemiptera: Psyllidae) from Iran
During a faunistic survey of the jumping plant-lice (Hemiptera: Psylloidea) in the Iranian province of Kerman in spring 2015, Cacopsylla dissimilis (Baeva) comb. nov. was collected on Salix pycnostachya. This species was previously known only from Tajikistan. It is reported here for the first time from Iran. The host species, Salix pycnostachya, is also newly recorded. We provide detailed morphological descriptions of adults and fifth instar immatures, and discuss differences to closely related species, in particular Cacopsylla nigrita (Zetterstedt)
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