Building test cases and oracles to automate the testing of web database applications

Many organizations rely on web applications that use back-end databases to store important data. Testing such applications requires significant effort. Manual testing alone is often impractical, so testers also rely on automated testing techniques. However, current automated testing techniques may produce false positives (or false negatives) even in a perfectly working system because the outcome of a test case depends on the state of the database which changes over time as data is inserted and deleted. The Automatic Database Tester (AutoDBT) generates functional test cases that account for database updates. AutoDBT takes as input a model of the application and a set of testing criteria. The model consists of a state transition diagram that shows how users navigate pages, a data specification that captures how data flows, and an update specification that shows how the database is updated. AutoDBT generates guard queries to determine whether the database is in a state conducive to performing and evaluating tests. AutoDBT also generates partial oracles to help validate whether a back-end database is updated correctly during testing. This paper describes the design of AutoDBT, a prototype implementation, several experiments with the prototype, and four case studies.     

Stochastic Geometry and Random Graphs for the Analysis and Design of Wireless Networks

Wireless networks are fundamentally limited by the intensity of the received signals and by their interference. Since both of these quantities depend on the spatial location of the nodes, mathematical techniques have been developed in the last decade to provide communication-theoretic results accounting for the network?s geometrical configuration. Often, the location of the nodes in the network can be modeled as random, following for example a Poisson point process. In this case, different techniques based on stochastic geometry and the theory of random geometric graphs ? including point process theory, percolation theory, and probabilistic combinatorics ? have led to results on the connectivity, the capacity, the outage probability, and other fundamental limits of wireless networks. This tutorial article surveys some of these techniques, discusses their application to model wireless networks, and presents some of the main results that have appeared in the literature. It also serves as an introduction to the field for the other papers in this special issue.     

Nanocomposite epoxy coatings containing rare earth ion-doped LaF3 nanoparticles: Film preparation and characterization

New epoxy-based nanostructured materials containing lanthanide ions doped LaF₃ nanoparticles were obtained by cationic UV-induced ring-opening polymerization.The lanthanide Er³⁺ and Yb³⁺ ions were added as dopant to LaF₃ nanoparticles. The synthesized NPs were solubilized into cyclohexene oxide and afterwards dispersed, in the range between 3 and 20 wt.%, into CE as dicycloaliphatic epoxy resin. The cured films were completely transparent and TEM analysis showed the absence of macroscopic agglomeration. The fast UV curing process was shown to be efficient on “freezing” the good nanometric dispersion achieved in the liquid formulations. These new materials could find suitable applications in optical communication and in LASER waveguide direct writing.     

Simultaneous desalination and power generation using solar energy

Using solar energy to produce fresh water and electricity simultaneously is a prospective way to solve the problems combining fresh water shortage, energy crisis and farm land degradation in Northern Victoria. This paper records the process of calculating the performance of the nozzle applying homogenous equilibrium model, designing and testing the prototype of such system using three different types of the nozzles in static and rotary systems. The research on the project is divided into two steps: first is about static system in which the spray nozzle is proved to be the best in both production of fresh water and power generation; while on the second stage, the convergent–divergent (C–D) nozzles are the best in rotary system. Some data were analyzed theoretically based on the test and the results found that the percentage of fresh water measured by experiment is consistent with the calculation using homogenous equilibrium expansion model (HEM), however, there is big difference in power generation between theory and experiments. Based on our experimental figures and analysis, the reasons for low power generation are found and a new model is proposed. According to the new model, a different reaction turbine using curve length C–D nozzles is designed to overcome the problems which were encountered in the previous prototype. After analyzing the efficiency of the cycle by T–s diagram, the evacuated tube solar collector integrated heat pipe is suggested to be applied on this system.     

3D Simulations to investigate initial condition effects on the growth of Rayleigh–Taylor mixing

The effect of initial conditions on the growth rate of turbulent Rayleigh–Taylor (RT) mixing has been studied using carefully formulated numerical simulations. An implicit large-eddy simulation (ILES) that uses a finite-volume technique was employed to solve the three-dimensional incompressible Euler equations with numerical dissipation. The initial conditions were chosen to test the dependence of the RT growth parameters (α_b, α_s) on variations in (a) the spectral bandwidth, (b) the spectral shape, and (c) discrete banded spectra. Our findings support the notion that the overall growth of the RT mixing is strongly dependent on initial conditions. Variation in spectral shapes and bandwidths are found to have a complex effect of the late time development of the RT mixing layer, and raise the question of whether we can design RT transition and turbulence based on our choice of initial conditions. In addition, our results provide a useful database for the initialization and development of closures describing RT transition and turbulence.     

Upper bound on the capacity of cognitive radio without cooperation

We derive an upper bound on the capacity of cognitive radio using the interference temperature concept. We do not assume any cooperation between the primary and the secondary user. First, assuming all four links associated with the primary/secondary transmitter/receiver experience Rayleigh fading, the capacity is achieved via the water-filling power allocation strategy, subject to an average secondary to primary interference to signal ratio (ISR) constraint and a peak ISR constraint. Second, we extend our result to the case with path loss as well as channel fading to reflect the geometric relations between link pairs and network size. Finally, we numerically show that for K_P primary receivers which are opportunistically scheduled, the capacity of cognitive radio asymptotically grows as logloglogK_P.     

The diagnostic value of serum lysozyme activity in inflammatory bowel disease

The inferior alveolar nerve was cut or the vessels entering the mandibular canal were damaged in 39 guinea pigs at 10 days of age. Possible changes in the incisors were recorded during a 100-day observation period whereafter the animals were killed and the skulls freed of soft tissues; at this time, 35 skulls were found suitable for further examination. The changes in the mandibular incisors on the operated side became observable 30-40 days post-operatively as discolourization, a 'trauma line' around the tooth, narrowing of the tooth or total loss of it's visible part. In the guinea pigs with the nerve cut (group A), such signs of maldevelopment were seen in 5 out of 19 animals, whereas the corresponding figure for the animals with the damaged vessels (group B) was 14/16. All incisors in group A and 13 out of 14 in group B recovered from the state of maldevelopment; one animal in group B showed complete loss of the incisor. The molar region was examined only from the cleaned skulls. In group A, the first molar was deformed in two animals; in group B, seven animals displayed either maldevelopment of the first molar or the first and second molar or complete loss of the first molar. No malformation of the third molar was observed. With two exceptions, the deformation or loss of molars occurred in combination with incisor maldevelopment. The malformations were considered to result from a disturbed blood supply. In group A, the dental changes may perhaps be ascribed to a short-term interference with the blood supply during the operation. The variable results in group B seem to imply that the mandibular teeth receive at least part of their blood supply from vessels besides those entering the mandibular canal. The innervation appears to have a subordinate role in the restoring of the morphology of continuously erupting teeth.     

Quantitative evaluation of the blood-brain barrier capacity to form dopamine from circulating L-DOPA

The ability of the blood-brain barrier to form dopamine from increasing doses of systemically administered L-DOPA has been studied in rats by a combination of chemical determination of dopamine, and histochemical and cytofluorometric measurements of L-DOPA and dopamine. The break-through of L-DOPA from the circulation into the brain parenchyma via the enzymatic blood-brain barrier was estimated by comparing the amount of newly formed dopamine in the caudate nucleus-putamen and in the cerebellum. The capillaries were found to efficiently trap L-DOPA in their walls, and an upper limit was reached (at an administered i.p. dose of 100 mg/kg of L-DOPA). It could be estimated that approximately 3% of the total dose of L-DOPA given was decarboxylated by the blood-brain barrier. The possible influence by the regional differences in perfusion of the two regions seen after administration of L-DOPA was ruled out in measurements of local cerebral blood flow using the 14C-ethanol technique.     

Bile acids: co-mutagenic activity in the Salmonella-mammalian-microsome mutagenicity test: brief communication

Of 30 bile acids tested, none was mutagenic in the Salmonella-mammalian-microsome test with indicator strains G46, TA1530, TA1535, TA1536, TA1537, TA1538, TA98, or TA100. However, when lithocholic acid or one of its conjugates was tested with suboptimal amounts of 2-aminoanthracene and phenobarbital-stimulated rat liver homogenate, enhancement and co-mutagenesis were observed if TA1538 was the indicator strain.     

Cytochemical localization of acetylcholine receptors at the neuromuscular junction by means of horseradish peroxidase-labeled alpha-bungarotoxin

The cytochemical localization of acetylcholine (ACh) receptors at the neuromuscular junction was investigated with a procedure utilizing alpha-bungarotoxin (alpha-BtX) labeled directly with horseradish peroxidase (HRP). Following incubation of tissues in the conjugate and reaction for peroxidase, activity was observed on the junctional folds of the motor endplate. A uniform layer of reaction product approximately 15 nm thick occurred over the apical portions of the junctional folds. Membranes at the bases of the synaptic cleft showed only small amounts of reaction product. Non-junctional regions of the muscle fiber were unreactive. Activity was also observed in the membrane of the axon facing the muscle surface, often including the axolemma overlying the "active zones" of the nerve terminal. Such presynaptic activity was still evident on nerve terminals disjuncted from the synapse by enzymatic treatment prior to incubation in the conjugate. This localization indicates the possible presence of presynaptic ACh receptors within the axolemma. In muscle denervated for 7-12 days, motor endplates were reactive and parajunctional sarcolemma showed slight activity, but most extrajunctional regions contained no obvious accumulations of reaction product. Activity at all sites was prevented by preincubation of tissues in native alpha-BTX prior to incubation in the conjugate and reaction for HRP. This procedure represents a simple and convenient method for the high resolution localization of ACh receptors.