Automated GUI performance testing

A significant body of prior work has devised approaches for automating the functional testing of interactive applications. However, little work exists for automatically testing their performance. Performance testing imposes additional requirements upon GUI test automation tools: the tools have to be able to replay complex interactive sessions, and they have to avoid perturbing the application’s performance. We study the feasibility of using five Java GUI capture and replay tools for GUI performance test automation. Besides confirming the severity of the previously known GUI element identification problem, we also describe a related problem, the temporal synchronization problem, which is of increasing importance for GUI applications that use timer-driven activity. We find that most of the tools we study have severe limitations when used for recording and replaying realistic sessions of real-world Java applications and that all of them suffer from the temporal synchronization problem. However, we find that the most reliable tool, Pounder, causes only limited perturbation and thus can be used to automate performance testing. Based on an investigation of Pounder’s approach, we further improve its robustness and reduce its perturbation. Finally, we demonstrate in a set of case studies that the conclusions about perceptible performance drawn from manual tests still hold when using automated tests driven by Pounder. Besides the significance of our findings to GUI performance testing, the results are also relevant to capture and replay-based functional GUI test automation approaches.     

Study of Silicon Cantilevers by the Photoacoustic Elastic Bending Method

Rectangular silicon cantilevers are studied by the photoacoustic (PA) elastic bending method. Experimental signals versus modulation frequency of the excitation optical beam are measured and analyzed in a frequency range from 20 Hz to 50 000 Hz. The procedure for experimental signal correction to eliminate the frequency characteristics of the measuring system is given. The corrected experimental signal shows a good correlation with theoretically calculated PA signal at frequencies below 32 000 Hz. The corrected experimental PA elastic bending signals for cantilevers with different thicknesses are analyzed. The experimental results allow identifying the resonant frequency (the first resonant mode) of the cantilever vibrations. These values are in good agreement with the theoretically computed values. A theoretical model of the optically excited Si cantilever is derived, taking into account plasmaelastic, thermoelastic, and thermodiffusion mechanisms. Dynamic relations for the amplitude and phase of electronic and thermal elastic vibrations in optically excited cantilevers are derived. The theoretical model is compared to the experimental results.     

Numerical modelling of the NGI-DSS test and cyclic threshold shear strain for degradation in sand

Ability of laboratory determination of a sand behaviour in static and dynamic loading conditions are influenced by (among other things): sample preparation, number of tests, size of strains, speed of loading and averaging of the errors during examination. Dynamic load per se causes accumulation of the pore water pressure and the phenomenon of stiffening-threshold-degradation which makes the understanding of the sand behaviour more difficult. The complex behaviour of granular material, i.e. sand, is caused by chemical and physical properties of individual particles and their mutual interaction. Obviously, these interrelationships could not be analysed on the basis of laboratory testing. One way to analyse it is numerically, with algorithm that takes into consideration the characteristics of individual particles as well as their interaction in the sand matrix. Discrete element method (DEM) is a numerical method which takes into consideration the discrete nature of sand and shape of particles and is used as an elementary research tool for sand behaviour. Program package PFC3D is based on DEM and allows the modelling of the laboratory equipment, materials and calibration of its micro-characteristics, based on experimental results. The research of cyclic threshold shear strain for degradation in sand includes observation and visualization of the sample preparation (creation of the material skeleton), pouring of the material (transition from liquid to meta-stable state), influence of the particle shape (interlocking, arching), consolidation (deformation of the skeleton) and development and braking of force chains through the sample. This paper explores the suitability of the selected numerical method for modelling of NGI-DSS device, calibration of the tested granular material (Nevada sand) and preparation of the sample for testing and presentation of the stiffening-threshold-degradation phenomenon.     

Ink-Jet Printing of Binders for Ceramic Components

Layered manufacturing methods for fabricating ceramic components can involve selective deposition of binder using ink-jet printing. Selection of a proper binder plays a critical role in fabricating parts with good surface finish, dimensional accuracy, and high resolution. Several polymeric solution-phase binders were investigated in terms of their physical properties, printing performance, and binder-powder bed interaction. It was observed that the molecular weight should be <15 000 for the binder to be penetrated into dense powder compacts. Binder infiltration kinetics and printed line width were also significantly influenced by powder-bed characteristics, such as surface roughness and pore size, as well as the physical properties of the binder, such as viscosity and surface tension.     

Integrated Dual-Display-Based 3G Mobile Phone / Wireless Terminal

In this paper, we describe HW and SW features of the developed prototype of a hybrid 3G mobile phone and wireless terminal, which provides integral video projection onto two VGA/2 displays that, when put side-by-side, form the integrated display with the ratio of the overall width to its overall height, equal to 4:3, so providing the integral video VGA format and enabling visual presentation of standard full-size web pages, PC mainstream SW screens (such as e.g. the ones of e-mail clients), multi-media content etc. When not in use, the displays can be fold back one onto each other, so preserving the industry-standard dimensions of the device. The two displays that share the image provide it with overall resolution of 640 x 480 pixels per inch. The device is driven by Texas Instruments OMAP 2420 multimedia processor with ARM1136 core and Linux operating system. In addition, the device is equipped with specially developped prototypes of unique spring/microgenerator-based battery charger as well as with ultra-thin mountable foil-based QWERTY keyboard.     

The corrosion behavior of Ti3SiC2 in common acids and dilute NaOH

Hot isostatically processed bulk, fine (3-5 μm) grained samples of Ti₃SiC₂ were immersed in concentrated and dilute hydrochloric, HCl, sulphuric, H₂SO₄, nitric, HNO₃, dilute hydrofluoric, HF, acids and sodium hydroxide, NaOH, solutions at room temperature. Based on six-months weight changes the dissolution rates of Ti₃SiC₂ in concentrated and dilute HCl, H₂SO₄ and dilute NaOH were found to be negligible (<2 μm/yr). In dilute HF and concentrated HNO₃ the corrosion rates were, respectively, ≈5 μm/yr and 13 μm/yr respectively. In contrast to Ti metal, the weight losses of Ti₃SiC₂ in dilute HNO₃ were higher (≈250-320 μm/yr) and depended on concentration. Post-immersion scanning electron microscopic micrographs of samples immersed in HNO₃ indicated that an oxygen rich Si-based layer forms on the surface of the samples. This implies that the Ti atoms are leached out into the HNO₃ solution, leaving behind a Si-rich layer that is ultimately oxidized. Cyclic polarization and potentiostatic i-t transients in dilute HCl and H₂SO₄ acids, strongly suggest that a thin irreversible electrically insulating layer forms on the surface of Ti₃SiC₂. Exposing a sample to a constant current density of 0.6 mA/cm² for two days resulted in the formation of a 5 μm thick SiO₂-based layer on the surface. The presence of such a layer would explain the excellent corrosion resistance of Ti₃SiC₂ in these acids.     

Early-life maternal separation and social isolation produce an increase in impulsive action but not impulsive choice.

Early life environment, events, and context, such as mother–offspring relationship, can have profound effects on future behavior and physiology. We investigated the effects of long-term maternal and social separation, through artificial rearing, on adult impulsivity. Rats were maternally reared (MR) or artificially reared (AR) and half of the AR rats were provided with replacement somatosensory stimulation intended to simulate maternal licking. There are at least 2 forms of impulsivity and we compared rats on 1 test of impulsive action (differential reinforcement of low rates of responding—DRL-20s) and 2 tests of impulsive choice (delay discounting and fixed consecutive number schedule—FCN). We found that AR rats are more action impulsive; however, this effect can be reduced by maternal licking-like stimulation. In contrast, AR rats did not display an increase in impulsive choice. Overall, these experiments show that early life maternal and social separation have different effects on the 2 forms of impulsivity. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Support Vector Machine State Estimation

The power system state estimator based on the support vector machine (SVM) and the weighted least squares (WLS) method is presented in the paper. The WLS provides state estimations necessary for creating SVM model which is then used for state estimation. The developed algorithm was tested on the IEEE systems, and the performance indicators were calculated in order to compare the accuracy of estimation and the measurement error filtering. The results indicate that the proposed hybrid model outperforms the classical WLS-based state estimation in terms of accuracy and improves measurement error filtering in comparison to the classical estimator.     

Expanding the representation of user activities

Space is often designed based on the representations of user activities (i.e. lists, organograms or flowcharts) that streamline user activities in stepwise, oversimplified, representations that may leave insufficient room for future activity development. However, design can anticipate activity development if users are able to represent their own activities while participating in the design process. A case study of a medical imaging centre reveals that once users have such opportunity, their spatial practices are not only taken into account but also expanded. The designers, the users and the researchers created a range of instruments to expand across three units of analysis: operations, actions and activities. As a result, the representations of space proffered by the designers were expanded to a space of representation for the users, where new ways of working were realized. Based on this study, an integrated model for the production of space and the development of activity is proposed.     

Project capabilities for operational outcomes in inter-organisational settings: The case of London Heathrow Terminal 2

Project and strategic management scholarship recognises the importance of project capabilities that allow firms to deliver projects. Although work on project capabilities is a fast-growing line of inquiry, little is still known about how clients assemble project capabilities to achieve operational outcomes in inter-organisational settings. This study seeks to apply theoretical work on project capabilities to the domain of infrastructure project delivery in order to understand how the assembly of project capabilities in temporary inter-organisational settings contributes to the delivery of operational outcomes. The empirical enquiry takes place in the context of the delivery of London Heathrow Terminal 2. Through an inductive theory building approach drawing upon semi-structured interviews with client-side project leadership, internal documents, publicly available data and ongoing engagement with the field, we identified three key capability-enabling mechanisms that help explain the genesis of project capabilities in inter-organisational settings: (1) reconfiguring project capabilities, (2) adapting project capabilities and (3) maintaining project capabilities. We discuss and expand these findings by engaging with theoretical ideas from project studies, and mainstream strategy, organisation, and management research to induce a dynamic model that can be helpful to guide future research, policy and management practices relating to the client side management of project capabilities.