Elastic Extension Research Articles

Evaluating the Performance of Multi-tenant Elastic Extension Tables

An important challenge in the design of databases that support mult i-tenant applications is to provide a platform to manage large volu mes of data collected fro m d ifferent businesses, social media networks, ema ils, news, online te xts, documents, and other data sources. To overcome this challenge we proposed in our previous work a mu lti -tenant database schema called Elastic Extension Tables (EET) that co mb ines multi -tenant relat ional tables and virtual re lational tables in a single database schema. Using this approach, the tenants’ tables can be extended to support the requirements of individual tenants. In this paper, we discuss the potentials of using EET mult i-tenant database schema, and show how it can be used for managing physical and virtual re lational data. We perform several e xperiments to measure the feasibility and effectiveness of EET by co mparing it with a comme rcia lly availab le mu lti-tenant schema mapping technique used by SalesForce.co m. We report significant performance improve ments obtained using EET when co mpared to Un iversal Tab le Sche ma Mapping (UTSM), ma king the EET schema a good candidate for the management of multitenant data in Software as a Service (SaaS) and Big Data applications.

Multi-tenant Elastic Extension Tables Data Management

Multi-tenant database is a new database solution which is significant for Software as a service (SaaS) and Big Data applications in the context of cloud computing paradigm. This multi-tenant database has significant design challenges to develop a solution that ensures a high level of data quality, accessibility, and manageability for the tenants using this database. In this paper, we propose a multi-tenant data management service called Elastic Extension Tables Schema Handler Service (EETSHS), which is based on a multi-tenant database schema called Elastic Extension Tables (EET). This data management service satisfies tenants’ different business requirements, by creating, managing, organizing, and administratinglarge volumes of structured, semi-structured, and unstructured data. Furthermore, it combines traditional relational data with virtual relational data in a single database schema and allows tenants to manage this data by calling functions from this service. We present algorithms for frequently used functions of this service, and perform several experiments to measure the feasibility and effectiveness of managing multi-tenant data using these functions. We report experimental results of query execution timesfor managing tenants’ virtual and traditional relational data showing that EET schema is a good candidate for the management of multi-tenant data for SaaS and Big Data applications.

The Cerruti problem in dipolar gradient elasticity

The classical three-dimensional Cerruti problem of an isotropic half-space subjected to a concentrated tangential load on its surface is revisited here in the context of dipolar gradient elasticity. This generalized continuum theory encompasses the analytical possibility of size effects, which are absent in the classical theory, and has proven to be very successful in modelling materials with complex microstructure. The dipolar gradient elasticity theory assumes a strain-energy density function, which besides its dependence upon the standard strain terms, depends also on strain gradients. In this way, this theory can be viewed as a first-step extension of classical elasticity. The solution method is based on integral transforms and is exact. Of special importance is the behaviour of the new solution near to the point of application of the load where pathological singularities exist in the classical solution (based on the standard theory). The present results show departure from the ones predicted by the classical elasticity theory. Indeed, continuous and bounded displacements are found at the point of application of the load. Such a behaviour of the displacement field is, of course, more natural than the singular behaviour present in the classical solution.

Neomycin and pentagalloyl glucose enhanced cross-linking for elastin and glycosaminoglycans preservation in bioprosthetic heart valves

Glutaraldehyde cross-linked bioprosthetic heart valves fail within 12-15 years of implantation due to limited durability. Glutaraldehyde does not adequately stabilize extracellular matrix components such as glycosaminoglycans and elastin, and loss of these components could be a major cause of degeneration of valve after implantation. We have shown earlier that neomycin-based cross-linking stabilizes glycosaminoglycans in the tissue but fails to stabilize elastin component. Here, we report a new treatment where neomycin and pentagalloyl glucose (PGG) were incorporated into glutaraldehyde cross-linking neomycin-PGG-Glutaraldehyde (NPG) to stabilize both glycosaminoglycans and elastin in porcine aortic valves. Invitro studies demonstrated a marked increase in extracellular matrix stability against enzymatic degradation after cross-linking and 10 month storage in NPG group when compared to glutaraldehyde controls. Tensile properties showed increased lower elastic modulus in both radial and circumferential directions in NPG group as compared to glutaraldehyde, probably due to increased elastin stabilization with no changes in upper elastic modulus and extensibility. The enhanced extracellular matrix stability was further maintained in NPG-treated tissues after rat subdermal implantation for three weeks. NPG group also showed reduced calcification when compared to glutaraldehyde controls. We conclude that NPG cross-linking would be an excellent alternative to glutaraldehyde cross-linking of bioprosthetic heart valves to improve its durability.

Power line failures and catastrophic wildfires under extreme weather conditions

Catastrophic wildland fires have resulted under extreme wind conditions due to power line system failures. Under conditions of “extreme fire weather”, multiple ignitions due to power lines over a broad geographic area can occur under conditions promoting explosive fire growth. Such instances have been observed in the US state of California in 2007, and several times in recent Australian history – most notably the lethal Black Saturday fires of 2009. Ignitions can occur from a variety of failure modes in the huge array of components making up distribution and transmission networks and their neighboring environment. These failures fall into two general categories however: elastic extension of either the conductors or surrounding objects (such as tree limbs) causing electrical contact and arcing, and fatigue failures under high strain conditions affecting system components (conductors, poles, crossarms) or surrounding objects (trees). Both failure classes show a strong dependence on increasing wind speed. Case studies will be shown demonstrating both of these categories. Greatly compounding these physical wind dependencies is the expectation that failure probability will increase sharply with wind speed in an extreme value statistical dependency, such as a reverse Weibull distribution. Outage data from electric distribution systems is shown to demonstrate a very strong increase with wind speed – suggesting that outage data from normal operation of an electrical grid may be used to gauge system vulnerability to extreme fire weather conditions. These results also underline the importance of having appropriate design requirements and contingency plans to account for reasonably foreseeable catastrophic weather conditions. Mitigation measures being discussed or implemented by regulators and utilities are discussed.

Nanoconfinement and the Strength of Biopolymers

This review examines size effects observed in the mechanical strength of biopolymers that are organized in microstructures such as fibrils, layered composites, or particle nanocomposites. We review the most important aspects that connect nanoconfinement of basic material constituents at critical length scales to the mechanical performance of the entire material system: elastic modulus, strength, extensibility, and robustness. We outline theoretical and computational analysis as well as experimentation by emphasizing two strategies found in abundant natural materials: confined fibrils as part of fibers and confined mineral platelets that transfer load through a biopolymer interface in nanocomposites. We also discuss the application of confinement as a mechanism to tailor specific material properties in biological systems.

Region of zero charging

Unknown phenomenon was observed on the oxidized surface of a number of metals in water solutions including nickel, palladium, and platinum. Elastic extension of the metal decreases the interface capacity in wide potential region which reaches 0.4 V in the case of palladium. Within such region, the oscillograms “estance vs. potential” disclose an unusually long and low flat section which may be considered as the expanded zero of the differential charge density. The decrease of the capacity points out strengthening the bond of the water molecules to the surface oxide under its elastic extension which thickens the hydrated envelops of the adsorbed ions. Along the flat section, the state of the interface is reversible without changing the structure of the surface oxide. The anodic boundary of the flat section can be used as a sign of reaching the oxide monolayer. In the equations of solid state electrocapillarity, the potential of zero charge is presented explicitly. Its derivative with respect to elastic deformation is independent of the electrode potential and shifts the reversible section of the estance curve along the ordinate.

Violation of the Law of Demand

Following the classic work of Mitjuschin, Polterovich and Milleron, necessary and sufficient as well as sufficient conditions have been developed for when the multicommodity Law of Demand holds. We show when the widely cited Mitjuschin and Polterovich sufficient condition also becomes necessary. Using this result, violation regions for the very popular Modified Bergson (or hyperbolic absolute risk aversion) class of utility functions are fully characterized in terms of preference parameters. For a natural extension of the constant elasticity of substitution member of the Modified Bergson family that is neither homothetic nor quasihomothetic, we create the first simple, explicit example of which we are aware that (i) fully characterizes violation regions in both the preference parameter and commodity spaces and (ii) analyzes the range of relative income and price changes within which violations occur.

A Hybrid Model for Equity Indices and Stochastic Interest Rates

The growth optimal portfolio (GOP) plays an important role in finance, in particular in derivative pricing, where it is employed as a num\'eraire portfolio, allowing to price contingent claims directly under the real world probability measure. This paper derives an extension of a time dependent constant elasticity of variance (TCEV) model which takes into account stochastic interest rate risk. This results in a hybrid framework that models the stochastic dynamics of the GOP and the short rate simultaneously. We estimate and compare a variety of continuous-time models for short-term interest rates using non-parametric kernel-based estimation. Taking interest rate dynamics into account, we show that the hybrid model remains highly tractable and fits well the observed dynamics of diversified equity indices and interest rates. Our results are important for pricing and hedging of various derivative products, allowing to derive closed-form solutions for standard derivatives. Across all models under consideration we find that the hybrid model with 3/2 dynamics for the interest rate provides the best fit to the data. It leads to the lowest prices and the least expensive hedges.

Study on the Inwall Crack Extension and Fatigue Life Evaluation for Deep-Sea Steel Catenary Riser under Wave and Current Action

Aimed at deep-sea steel catenary risers(SCRs) transporting supercritical or dense CO2, this paper uses the macroscopic pipeline-transporting finite element model and the microscopic pipewall crack growth model to numerically simulate corrosive-inwall-defect-induced crack extension along radial direction for the deep-sea riser which is subjected to wave and current loads. Meanwhile, based on linear elastic fracture mechanics and fatigue crack extension theory, the effect of wave height on the fatigue life of the pipewall at touchdown zone is discussed. The above-mentioned study in this paper is expected to give a good reference to the similar study for oil&gas SCRs.

Mechanical and kinetic properties of β-cardiac/slow skeletal muscle myosin

We aimed to establish reference parameters to identify functional effects of familial hypertrophic cardiomyopathy-related point mutations in the β-cardiac/slow skeletal muscle myosin heavy chain (β-cardiac/MyHC-1). We determined mechanical and kinetic parameters of the β-cardiac/MyHC-1 using human soleus muscle fibers that express the same myosin heavy chain (MyHC-1) as ventricular myocardium (β-cardiac). The observed parameters are compared to previously reported data for rabbit psoas muscle fibers. We found all of the examined kinetic parameters to be slower in soleus fibers than in rabbit psoas muscle. Somewhat surprisingly, however, we also found that the stiffness of the β-cardiac/MyHC-1 head domain is more than 3-fold lower than the stiffness of the fast isoform of psoas fibers. Furthermore, and different from rabbit psoas muscle, in human soleus fibers both the occupancy of force-generating cross-bridge states as well as the elastic extension of force-generating heads increase with temperature. Thus, a myosin head in the force generating states makes an increasing contribution to force with temperature. We support some of our fiber data by data from in vitro motility and optical trapping assays. Initial findings with FHC-related point mutations in the converter imply that the differences in stiffness of the head domain between the slow and fast isoform may well be due to particular differences in the amino acid sequence of the converter. We show that the slower kinetics may be linked to a larger flexibility of the β-cardiac/MyHC-1 isoform compared to fast MyHC isoforms.

Axial changes in apoplast properties in the elongation zone of maize mesocotyl

Changes in extensibility of cell walls and composition of apoplastic solution along the elongation zone were studied in mesocotyls of etiolated seedlings of maize (Zea mays L.). It was found that plastic and elastic extensibility of cell walls was much greater in the cells with a high rate of elongation. Basipetal decrease in hydrogen peroxide concentration in the apoplast (from 5.1 to 2.0 μM) was detected. We determined the activity of cell wall enzymes participating in H2O2 metabolism and found that in basal direction, potential ability of these enzymes to decompose H2O2 rises stronger than the ability to produce it. We found a basipetal decrease in polyamine oxidase activity, an increase in oxalate oxidase activity, and a rise in the ratio between peroxidase and NADH-oxidase activities of peroxidases. IAA (10−6 M) promoted elongation of mesocotyl segments, induced a steady elevation of H2O2 content in the apoplast, an increase in NADH-oxidase activity of peroxidases, and a transient decrease in oxalate oxidase activity. Treatment with ABA (10−4 M) suppressed elongation of mesocotyl segments, induced a transient elevation of H2O2 content in the apoplast, and a decrease in oxalate oxidase activity. It was shown that the main metabolites of apoplastic solution are glucose (20–30 mM), fructose (6–7 mM), malic acid (3 mM), and amino acids, namely, Asp, Glu, Asn, Gln, Ala, Val, Ser, Thr, and Phe. In basal direction, we observed a decrease in the content of glucose (from 30 to 20 mM), inositol (from 0.24 to 0.08 mM), and total amino acids (from 5.5 to 3.3 mM), whereas concentration of orthophosphate (3 mM) and malate (3 mM) did not change significantly. A relationship between the detected changes in the apoplast composition and basipetal decrease in the elongation rate of mesocotyl cells is discussed.

Chemical composition, functional and sensory characteristics of wheat-taro composite flours and biscuits.

The physicochemical, alveographic and sensory characteristics of precooked taro-wheat composite flours and their biscuits were investigated. A 2x7 factorial design consisting of two varieties of taro flour (Red Ibo Ngaoundere, RIN, and egg-like varieties) and 7 levels of wheat substitutions (0, 5, 10, 15, 20, 25 and 30%) was used for this purpose. It was observed that water absorption capacity (range 95-152g/100g), water solubility index (range 18.8-29.5g/100g) and swelling capacity (range 125.4-204.6mL/100g) of composite flours significantly (p < 0.05) increased with increase in taro level. Conversely the dough elasticity index (range 59.8-0%), extensibility (78-22mm) and strength (range 281-139 × 10(-4) joules) significantly (p < 0.05) diminished with increase in wheat substitution. Up to 10% substitution with RIN taro flour and 15% with egg-like taro flour, the composite taro-wheat dough exhibited elasticity indices acceptable for the production of baking products, whereas at all levels of taro substitution, the composite biscuits samples were either acceptable as or better (5-10% substitution with RIN flour) than 100% wheat biscuit.

Chirality-Dependent Anisotropic Elastic Properties of a Monolayer Graphene Nanosheet

An analytical approach is presented to predict the elastic properties of a monolayer graphene nanosheet based on interatomic potential energy and continuum mechanics. The elastic extension and torsional springs are utilized to simulate the stretching and angle variation of carbon-carbon bond, respectively. The constitutive equation of the graphene nanosheet is derived by using the strain energy density, and the analytical formulations for nonzero elastic constants are obtained. The in-plane elastic properties of the monolayer graphene nanosheet are proved to be anisotropic. In addition, Young's moduli, Poisson's ratios and shear modulus of the monolayer graphene nanosheet are calculated according to the force constants derived from Morse potential and AMBER force field, respectively, and they were proved to be chirality-dependent. The comparison with experimental results shows a very agreement.

The Substep of Myosin Va is Associated with an Increase in Stiffness of the Myosin Va Head Domain

Vertebrate myosin Va transports cargo by processive movement that is optimized by coordination of the two heads via intramolecular strain (Veigel et al Nat Cell Biol 2002). Such coordination requires substantial stiffness of the head domains. Otherwise one head cannot “sense” changes in the other head. Substantial stiffness, however, generates substantial restoring forces impeding diffusive movement of the free head to its next binding site about 10nm beyond the throw generated by the stroke of the myosin Va. Such conflicting constraints raise the question whether stiffness of the myosin Va head domain may change during the ATPase cycle.We measured myosin Va head stiffness with a modified three-bead trapping assay. One bead of the dumbbell was attached end-on to the actin filament to reduce compliance of this link. To determine myosin Va stiffness we applied ramp-shaped movements to the stage and followed the position of the end-on attached bead. When a myosin Va head bound to the dumbbell, the dumbbell started to follow the stage movement, however, with reduced amplitude. The reduced amplitude we attributed to elastic distortion of the myosin Va head, elastic extension of the actin-bead link, and compliance between the myosin Va molecule and the nitrocellulose coated third bead. Compliances of the actin-bead links were determined according to Smith et al. (Biophys J 2001) and by force-extension curves.Coinciding with the substep in myosin Va binding events bead movement suddenly followed the imposed stage movement more closely than before the substep, indicating suddenly reduced elastic extension of myosin Va. Quantitative analysis suggests a stiffness of the chicken myosin Va head domain of about 0.2pN/nm before the substep and a 2.5 to 3-fold increase in stiffness with the substep.

In vitro and in vivo skin anti-aging evaluation of gel containing niosomes loaded with a semi-purified fraction containing gallic acid from Terminalia chebula galls

Context: The galls of Terminalia chebula Retz. (Combretaceae) frequently appear in many Thai Lanna medicinal plant recipes for promotion of longevity.Objective: The objective of this study was to evaluate the skin anti-aging of gel containing niosomes loaded with a semi-purified fraction containing gallic acid from T. chebula galls.Method: The semi-purified fraction containing phenolic compounds including gallic acid isolated from T. chebula galls loaded in non-elastic or elastic niosomes, and its developed gel, were evaluated for rabbit skin irritation by the closed patch test and skin anti-aging in human volunteers by measuring skin elasticity and roughness.Results: Gel containing the fraction unloaded (SS) or loaded in non-elastic (SN) or elastic (SE) niosomes and gallic acid loaded in non-elastic (GN) or elastic (GE) niosomes showed no skin irritation, whereas the unloaded gallic acid (GS) gave the irritation in rabbit’s skin by the closed patch test. The % parameter changes of skin elastic recovery and skin elastic extension when applied with SN and SE gels were +28.73 and +32.57; −21.25 and −22.63%, respectively. SN and SE gel also showed a significant decrease of the maximum and average roughness values with the parameter changes of −29.43 and −32.38; −39.47 and −35.28%, respectively.Conclusion: The semi-purified fraction loaded in niosomes indicated not only higher chemical stability of gallic acid containing in the fraction, but also more in vivo anti-aging activities than the unloaded fraction when incorporated in gel.

ANTITRUST AND COMPETITION IN TWO-SIDED MARKETS

This article extends antitrust analysis to two-sided markets in which a virtual monopolist competes with local bricks-and-mortar dealers. The discussion examines the market power of an Internet market maker as well as an Internet matchmaker. The analysis shows that equilibrium in a two-sided market can be characterized as a one-sided market in which transaction demand depends on the bid-ask spread of the central market maker. This allows for a straightforward extension of critical demand elasticity and critical loss analysis from one-sided markets to two-sided markets, with antitrust tests based on the hypothetical monopolist's bid-ask spread. Antitrust analysis of a one-sided market also carries over to a two-sided market with a matchmaker where antitrust tests are based on the sum of participation fees.

Analysis of the shortness of offset ink as a function of tack on paper by comparing elastic and Hencky strain extension

We conducted a study to differentiate between the effects of the extensional length of an offset ink and its film split tack behavior related to the blanket paper ink film separation on a press. Two separation techniques were used to study these phenomena separately: constant force and thus varying acceleration, giving sensitivity biased toward ink length; and constant extensional strain rate (Hencky strain rate), giving sensitivity biased toward ink on paper tack and viscosity. In general, high intrinsic ink tack level seems to correspond to high ink on paper tack value. Both methods identify the tack cycle as ink oil is removed by capillary action into the substrate. The extensional strain rate matches more closely the film splitting effect of the print cylinders, identifying effects of extensional viscosity. In contrast, the constant force technique is sensitive to length of an ink as a result of tack build. A range of inks of different shortness (inverse length) was analyzed using the two methods on coated paper. Development of tack differed for the range of inks according to shortness, and thus the way they responded to the two measurement techniques. Differentiation was obtained between the behavior during tack rise, the balance between adhesion and maximum internal tack, and the tack fall over time. The development of shortness as a function of ink on paper tack provides new insights into the basis for piling, paper strength demands, and runnability under different press dynamics.

Dynamic Elastic-Plastic Analysis of Reinforcement Geogrids Applied in High Earth-Rockfilled Dam Slope

Considering the dynamic response of high earth-rockfilled dam, dynamic elasto-plastic analysis method for dam slope reinforcement with geogrids was set up. Based on this model, the paper analyzed the deformation and failure mechanism of dam slope, as well as the effect of connection, the length, the spacing and the stiffness of geogrid on dam with deformation. The results show that geogrids with high elastic modulus and proper extensibility will apparently reduce the deformation and imporve the stability of the dam slope. In the case of high dam slope, the reinforcement length of geogrids is supposed to be 2a (a is the slip surface length), and the spacing is 2m.

A sequence of physical processes determined and quantified in LAOS: Application to a yield stress fluid

Recently, large-amplitude oscillatory shear has been studied in great detail with emphasis on its impact on the material response. Here we present a conceptually different, robust methodology based on viewing the stress waveforms as representing a sequence of physical processes. This novel approach provides the viscous and elastic contributions while overcoming the problems with infinite series encountered by Fourier transformation. Application to a soft colloidal star glass leads to the unambiguous determination and quantification of rate-dependent static and dynamic yield stresses, the rationalization of the response to strain sweeps and the post-yield regime by introducing the apparent cage modulus, and a connection to the steady-shear stress, all from a single-amplitude experiment. We propose that this approach is generic, but focus in this contribution only on a yield stress material which exhibits repeating cycles of (i) elastic extension, (ii) yielding, (iii) flow, and (iv) reformation. We show that this approach is qualitatively consistent with the Fourier–Chebyshev analysis.