An investigation into the usability of electronic voting systems for complex elections

Many studies on electronic voting evaluate their usability in the context of simple elections. Complex elections, which take place in many European countries, also merit attention. The complexity of the voting process, as well as that of the tallying and verification of the ballots, makes usability even more crucial in this context. Complex elections, both paper-based and electronic, challenge voters and electoral officials to an unusual extent. In this work, we present two studies of an electronic voting system that is tailored to the needs of complex elections. In the first study, we evaluate the effectiveness of the ballot design with respect to motivating voters to verify their ballot. Furthermore, we identify factors that motivate voters to verify, or not to verify, their ballot. The second study also addresses the effectiveness of the ballot design in terms of verification, but this time from the electoral officials’ perspective. Last, but not least, we evaluate the usability of the implemented EasyVote prototype from both the voter and electoral official perspectives. In both studies, we were able to improve effectiveness, without impacting efficiency and satisfaction. Despite these usability improvements, it became clear that voters who trusted the electronic system were unlikely to verify their ballots. Moreover, these voters failed to detect the “fraudulent” manipulations. It is clear that well-formulated interventions are required in order to encourage verification and to improve the detection of errors or fraudulent attempts.     

Convergence analysis of hybrid cellular automata for topology optimization

The hybrid cellular automaton (HCA) algorithm was inspired by the structural adaptation of bones to their ever changing mechanical environment. This methodology has been shown to be an effective topology synthesis tool. In previous work, it has been observed that the convergence of the HCA methodology is affected by parameters of the algorithm. As a result, questions have been raised regarding the conditions by which HCA converges to an optimal design. The objective of this investigation is to examine the conditions that guarantee convergence to a Karush-Kuhn-Tucker (KKT) point. In this paper, it is shown that the HCA algorithm is a fixed point iterative scheme and the previously reported KKT optimality conditions are corrected. To demonstrate the convergence properties of the HCA algorithm, a simple cantilevered beam example is utilized. Plots of the spectral radius for projections of the design space are used to show regions of guaranteed convergence.     

Dynamic aspects of cerium dioxide sintering: HT-ESEM study of grain growth and pore elimination

Sintering of CeO₂ is studied in situ by high temperature scanning environmental microscopy (HT-ESEM) at T = 1400 °C. The morphological modifications of a single grains population are recorded for 6 h. Kinetic parameters are extracted from image series. The local grain growth determined from the single population studied in situ is compared to the general grain growth obtained by classical ex situ technique. Using HT-ESEM for sintering study is validated. The grain boundary velocities range between 0 and 5 μm h⁻¹, with a mean value of about 1 μm h⁻¹. The migration of the intragranular surface pores is described. Their velocities range between 0.4 and 1.2 μm h⁻¹ and depend on pore diameters: the smaller the pore, the faster the pore velocity. The time required to fill a pore that arises at the sample surface is determined as a function of pore diameter. The time for pore elimination dependence with the pore diameters is also established.     

Zipping effect on omniphobic surfaces for controlled deposition of minute amounts of fluid or colloids

When a drop sits on a highly liquid-repellent surface (super-hydrophobic or super-omniphobic) made of periodic micrometer-sized posts, its contact-line can recede with very weak mechanical retention providing that the liquid stays on top of the microsized posts. Occurring in both sliding and evaporation processes, the achievement of low-contact-angle hysteresis (low retention) is required for discrete microfluidic applications involving liquid motion or self-cleaning; however, careful examination shows that during receding, a minute amount of liquid is left on top of the posts lying at the receding edge of the drop. For the first time, the heterogeneities of these deposits along the drop-receding contact-line are underlined. Both nonvolatile liquid and particle-laden water are used to quantitatively characterize what rules the volume distribution of deposited liquid. The experiments suggest that the dynamics of the liquid de-pinning cascade is likely to select the volume left on a specific post, involving the pinch-off and detachment of a liquid bridge. In an applied prospective, this phenomenon dismisses such surfaces for self-cleaning purposes, but offers an original way to deposit controlled amounts of liquid and (bio)-particles at well-targeted locations.     

Physicochemical characterization of Au/CeO2 solids. Part 2: The impregnation preparation method

Au/CeO₂ solids with different gold contents were prepared using the impregnation method. Electron microscopy (SEM and TEM) studies indicated the formation of both nanoparticles and large gold particles on the surface of the ceria support. SEM and XRD analyses revealed that the number and size of large particles increases with the gold content in the solid. The XPS technique showed that 90% of the total gold is in the metallic form Au⁰ while the remaining 10% were cationic gold species Au⁺. These latter were formed following calcination under dry air at 400 °C and are located in the proximity of the O²⁻ and/or Cl⁻ present on the support. These Au⁺ species are present at the edge of gold particles and they were reduced into metallic gold when the solid was vacuum treated (5–7.10⁻⁴ mbar) at 400 °C for 1 h. When air was adsorbed at room temperature on the latter vacuum treated solids, two EPR signals were obtained. The first one was assigned to O₂⁻ species whereas attributing the second signal was difficult and required a more detailed investigation that will be presented in a forthcoming work.     

Electroplating silicon and titanium in molten fluoride media

The electrolytic reduction mechanisms of K₂SiF₆ and K₂TiF₆ solutions in LiF-KF and LiF-NaF-KF eutectic mixtures have been studied at temperatures between 550 and 850°C. The reduction of K₂SiF₆ proceeds by two successive electron transfers, $$Si(IV) + 2e \to Si(II) + 2e \to Si$$ coupled with an antidisproportionation reaction $$Si(IV) + Si \underset{{k_b }}{\overset{{k_b }}{\longleftrightarrow}} 2Si(II)$$ Very pure thin silicon layers, up to 300 μm thick, were obtained on a silver substrate. The cathodic reduction of TiF ₆ ^2? ions occurs in two well separated reversible steps, $$TiF_6^{2--} + e \to TiF_6^{3--} + 3e \to Ti + 6F^--$$ Adherent coatings of pure titanium were found to be linked to the copper substrate by an interdiffusion sublayer comprising Ti₂Cu, TiCu, Ti₂Cu₃ and TiCu₄ which were formed in a narrow potential domain preceding titanium deposition.