Rewiring strategies for changing environments

A typical pervasive application executes in a changing environment: people, computing resources, software services and network connections come and go continuously. A robust pervasive application needs adapt to this changing context as long as there is an appropriate rewiring strategy that guarantees correct behavior. We combine the MERODE modeling methodology with the ReWiRe framework for creating interactive pervasive applications that can cope with changing environments. The core of our approach is a consistent environment model, which is essential to create (re)configurable context-aware pervasive applications. We aggregate different ontologies that provide the required semantics to describe almost any target environment. We present a case study that shows a interactive pervasive application for media access that incorporates parental control on media content and can migrate between devices. The application builds upon models of the run-time environment represented as system states for dedicated rewiring strategies

Fibre engineered cementitious materials (FECM) optimization by the use of hybrid polypropylene fibres and supplementary powder addition

Development of Fibre Engineered Cementitious Materials with Self-Healing Capacity (SH-FECM) was an important goal of the recent research programmes conducted in NIRD URBAN-INCERC Cluj-Napoca Branch. Several theoretical and experimental studies were performed in order to improve the composites, considering both, fresh and hardened state properties and also the performance as filling material of the narrow spaces at the beam to column interface within the Hybrid spatial joint model [1]. Present studies are focused in optimising the already developed mixtures regarding several aspects: the self-compacting behaviour of the fresh composites, considering the increased risk of balling effect when using 2% (of volume) of polymeric fibres as disperse reinforcement of the cementitious matrix, bleeding control during and after the mixes sequences by using supplementary powder addition, evaluation of the mixes when using a combination of two distinct types of polypropylene fibres, and development of controlled multiple cracks under loading, etc. The present paper offers the first results regarding the performance of the cement based composites, namely the fresh state self-compacting effect and also the flexural and compressive strengths at 7 and 28 days of age. Initial conclusions when replacing the traditional silica sand as aggregate of initial mixes with regular sand (0/1 mm fraction) are also considered. The Self-Healing potential of the mixes will be evaluated further on, ensuring the complete range of characteristics related to durability improving, repair and maintenance cost reduction and superior structural performance, in the context of the expected features of the sustainable development

Mapping of positive selection sites in the HIV-1 genome in the context of RNA and protein structural constraints

<p>Abstract</p> <p>Background</p> <p>The HIV-1 genome is subject to pressures that target the virus resulting in escape and adaptation. On the other hand, there is a requirement for sequence conservation because of functional and structural constraints. Mapping the sites of selective pressure and conservation on the viral genome generates a reference for understanding the limits to viral escape, and can serve as a template for the discovery of sites of genetic conflict with known or unknown host proteins.</p> <p>Results</p> <p>To build a thorough evolutionary, functional and structural map of the HIV-1 genome, complete subtype B sequences were obtained from the Los Alamos database. We mapped sites under positive selective pressure, amino acid conservation, protein and RNA structure, overlapping coding frames, CD8 T cell, CD4 T cell and antibody epitopes, and sites enriched in AG and AA dinucleotide motives. Globally, 33% of amino acid positions were found to be variable and 12% of the genome was under positive selection. Because interrelated constraining and diversifying forces shape the viral genome, we included the variables from both classes of pressure in a multivariate model to predict conservation or positive selection: structured RNA and α-helix domains independently predicted conservation while CD4 T cell and antibody epitopes were associated with positive selection.</p> <p>Conclusions</p> <p>The global map of the viral genome contains positive selected sites that are not in canonical CD8 T cell, CD4 T cell or antibody epitopes; thus, it identifies a class of residues that may be targeted by other host selective pressures. Overall, RNA structure represents the strongest determinant of HIV-1 conservation. These data can inform the combined analysis of host and viral genetic information.</p

Experimental application of sum rules for electron energy loss magnetic chiral dichroism

We present a derivation of the orbital and spin sum rules for magnetic circular dichroic spectra measured by electron energy loss spectroscopy in a transmission electron microscope. These sum rules are obtained from the differential cross section calculated for symmetric positions in the diffraction pattern. Orbital and spin magnetic moments are expressed explicitly in terms of experimental spectra and dynamical diffraction coefficients. We estimate the ratio of spin to orbital magnetic moments and discuss first experimental results for the Fe L_{2,3} edge.Comment: 11 pages, 2 figure

Dynamic loading performance of fibre engineered cementitious materials with self-healing capacity (SH-FECM)

Structural performance under dynamic actions, apart from geometric characteristics, supports loading conditions, design methods, etc., is mainly related to the intrinsic material properties of the structural elements. Earthquake events, as typical examples of accidental dynamic loading, involve strong stress waves, induced in the structure in very short time intervals. Increased loading rates, difficult to withstand, are generated. Therefore, superior complementary characteristics, namely strength and ductility, are required in order to avoid sudden failure and, as direct consequence, casualties and economic losses. Engineered Cementitious Composite (ECC), a unique type of mortar framed in the category of high-performance fibre-reinforced cementitious composites (HPFRCC), is defined by metal-like behaviour due to the multiple cracking patterns developed under applied loads. ECC proves an increased deformability potential and, as consequence ductility, which indicate a superior performance when subjected to dynamic actions. The multiple microcracking property of the composite, together with some specific matrix attributes and environmental conditions, also ensures an already proved self-healing potential [1], [2]. All these intrinsic material characteristics induce increased durability, considerable material and manpower reduction, improved structural performance and reduced repair and maintenance costs. Consequently, ECC is a valuable building material alternative and it is obvious that will bring a major to future sustainable development. This paper presents the incipient evaluation of the dynamic performance of Fibre Engineered Cementitious Materials with Self-Healing potential (SH-FECM), developed using the ECC theoretical and applied design principles, in the terms of the strain rate sensitivity, which proves to be an essential and difficult to control parameter

Testing superabsorbent polymer (SAP) sorption properties prior to implementation in concrete: results of a RILEM Round-Robin Test

This article presents the results of a round-robin test performed by 13 international research groups in the framework of the activities of the RILEM Technical Committee 260 RSC "Recommendations for use of superabsorbent polymers in concrete construction''. Two commercially available superabsorbent polymers (SAP) with different chemical compositions and gradings were tested in terms of their kinetics of absorption in different media; demineralized water, cement filtrate solution with a particular cement distributed to every participant and a local cement chosen by the participant. Two absorption test methods were considered; the tea-bag method and the filtration method. The absorption capacity was evaluated as a function of time. The results showed correspondence in behaviour of the SAPs among all participants, but also between the two test methods, even though high scatter was observed at early minutes of testing after immersion. The tea-bag method proved to be more practical in terms of time dependent study, whereby the filtration method showed less variation in the absorption capacity after 24 h. However, absorption followed by intrinsic, ionmediated desorption of a specific SAP sample in the course of time was not detected by the filtration method. This SAP-specific characteristic was only displayed by the tea-bag method. This demonstrates the practical applicability of both test methods, each one having their own strengths and weaknesses at distinct testing times

East-central Florida pre-Columbian wood sculpture: Radiocarbon dating, wood identification and strontium isotope studies

A suite of scientific approaches are applied to four pre- Columbian wood sculptures from east-central Florida, comprising new radiocarbon determinations, wood identification and strontium isotope analysis. The dates for three large zoomorphic carvings recovered from the St. Johns River at Hontoon Island place them between ca. AD 1300 and 1600, suggesting that they belonged to a tradition of erecting largescale pine carvings spanning at least some centuries. Two of the carvings have strontium isotope signals consistent with the immediate vicinity of the site, while the third differs significantly. Baseline data for biologically available strontium from sampled modern trees indicates considerable isotopic variability over short distances, making it difficult to determine the source of the wood used for this third carving. The only anthropomorphic sculpture, recovered from the vicinity of Tomoka State Park, dates to a similar time period, ca. AD 1440-1620. Our study confirms the wood's previous identification as belonging to the genus Peltophorum, a tropical hardwood thought not to be native to Florida. Its strontium isotope value is consistent with its find location, but equally may be found over much of southern Florida, where perhaps the species grew in the past. The results clarify the chronology for a stylistically distinctive carving tradition, as well as raising questions concerning the exchange of organic materials over varying distances. Highlights • 14C results for four east-central Florida carvings (Hontoon Island; Tomoka State Park) range ca. AD 1300-1600, spanning the proto-historic/historic periods • 87Sr/86Sr results for two of the three Hontoon carvings are consistent with the immediate locale, while the third suggests a different provenance • Pinus sp. was used at Hontoon, while Peltophorum sp., currently not native to Florida, was used at Tomoka</p