Quantum circuit’s reliability assessment with VHDL-based simulated fault injection

This paper presents a VHDL-based simulated fault injection (SFI) methodology for quantum circuits. The main objective is to attain a high error modeling capability at a technology independent level. For this purpose, gate level simulation models for quantum circuits have been developed using VHDL. The proposed methodology relies on specific techniques inspired from the simulated fault injection techniques developed for classical CMOS circuits: saboteurs and mutants. In order to perform the simulation campaigns, a library of quantum gates and simulated fault injection components has been developed. The simulation results show that a wide range of quantum faults and error models has been addressed. Furthermore, a comparison between the two SFI techniques is presented.     

Synthesis and characterization of side-chain poly(methacrylate)s bearing new azo-moieties

New side-chain poly(methacrylate)s with azo moieties were prepared by free radical copolymerization, starting from methyl methacrylate (MMA) and some original azo-monomers. The chromophore content was evaluated from ¹H-NMR spectroscopy and elemental analyses; all structures exhibited a high content of azobenzene units. UV–Vis measurements have also supported this fact. Reactivity ratios for the methacrylate systems and their corresponding Q–e values were calculated based on several initial feed compositions (MMA and the newly synthesized azo-monomers) using an integral method with its appropriate software. The polymers were also characterized by FTIR, SEC and DSC-TGA techniques. The coloured poly(methacrylate)s exhibited glass transition temperatures between 141 and 168 °C and thermal stabilities up to 306 °C.     

Random walk method for the two‐ and three‐dimensional Laplace,Poisson and Helmholtz's equations

The random walk method (RWM) is developed here for solving the Laplace, Poisson, and Helmholtz equations in two and three dimensions. The RWM is a local method, i.e. the solution at an arbitrary point can be determined without having to obtain the complete field solution. The method is based on the properties of diffusion processes, the Itô formula, the Dynkin formula, the Feynman–Kac functional, and Monte Carlo simulation. Simplicity, stability, accuracy, and generality are the main features of the proposed method. The RWK is inherently parallel and this fact has been fully exploited in this paper. Extensive numerical results have been presented in order to understand the various parameters involved in the method. Copyright © 2001 John Wiley & Sons, Ltd.     

Magnetotransport study on as-grown and annealed n- and p-type modulation-doped GaInNAs/GaAs strained quantum well structures

We report the observation of thermal annealing- and nitrogen-induced effects on electronic transport properties of as-grown and annealed n- and p-type modulation-doped Ga_{1 - x}In_xN_yAs_{1 - y} (x = 0.32, y = 0, 0.009, and 0.012) strained quantum well (QW) structures using magnetotransport measurements. Strong and well-resolved Shubnikov de Haas (SdH) oscillations are observed at magnetic fields as low as 3 T and persist to temperatures as high as 20 K, which are used to determine effective mass, 2D carrier density, and Fermi energy. The analysis of temperature dependence of SdH oscillations revealed that the electron mass enhances with increasing nitrogen content. Furthermore, even the current theory of dilute nitrides does not predict a change in hole effective mass; nitrogen dependency of hole effective mass is found and attributed to both strain- and confinement-induced effects on the valence band. Both electron and hole effective masses are changed after thermal annealing process. Although all samples were doped with the same density, the presence of nitrogen in n-type material gives rise to an enhancement in the 2D electron density compared to the 2D hole density as a result of enhanced effective mass due to the effect of nitrogen on conduction band. Our results reveal that effective mass and 2D carrier density can be tailored by nitrogen composition and thermal annealing-induced effects.

PACS

72.00.00; 72.15.Gd; 72.80.Ey     

Photoluminenscence Blinking Dynamics of Colloidal Quantum Dots in the Presence of Controlled External Electron Traps

The effect of the external charge trap on the photoluminescence blinking dynamics of individual colloidal quantum dots is investigated with a series of colloidal quantum dot–bridge–fullerene dimers with varying bridge lengths, where the fullerene moiety acts as a well‐defined, well‐positioned external charge trap. It is found that charge transfer followed by charge recombination is an important mechanism in determining the blinking behavior of quantum dots when the external trap is properly coupled with the excited state of the quantum dot, leading to a quasi‐continuous distribution of ‘on' states and an early fall‐off from a power‐law distribution for both ‘on' and ‘off' times associated with quantum dot photoluminescence blinking.     

Copolymerization of a bisanthracene compound with bismaleimides by Diels–Alder cycloaddition

Four new polymers have been synthesized via succesive Diels–Alder cycloadditions of a bisdiene compound bearing two anthracene groups and four bisdienophiles, all containing bismaleimide functions. The polycondensation reaction was performed in N,N‐dimethylacetamide at 120 °C leading to polymers soluble in polar solvents having molecular weights lower than 6000 g mol^?1. © 2001 Society of Chemical Industry     

The computation of Pareto-optimal set in multicriterial optimization of rapid prototyping processes

The purpose of this research is the multicriterial optimization of rapid prototyping processes. The mathematical model of the optimization problem takes into consideration as optimization criteria, surface quality of the prototype and the time of manufacturing. Based on the mathematical model, a practical method to find the Pareto-optimal set is developed, as a main goal. To solve the optimization problem, a computer program for rapid prototyping processes simulation was designed. The program calculates the geometry of successive layers, as well as the necessary time for their materialization. Depending on the importance degree of each optimization criterion, the program offers the optimal solution. In addition, when it is necessary, the program allows the user intervention in solving the problem optimization.The theoretical concepts presented in this research are very suggestively illustrated on a comprehensive case study. Starting from the Pareto-optimal set diagrams for the cases of LOM and SLS technologies, the optimal solutions are graphically illustrated in a very suggestive manner.     

Static verification of component composition in contextual composition frameworks

Contextual component frameworks, such as Enterprise JavaBeans (EJB), allow for components to specify boundary conditions for the runtime context. These conditions are satisfied at runtime by services of the underlying platform, thus ensuring that the context in which components run exhibits properties that allow them to operate correctly. Depending on how components call each other, it is possible that satisfying such conditions lead to problems such as reduced performance due to redundant service execution, or permanent errors (composition mismatches), due to incompatible boundary conditions. Currently, the semantics of these boundary conditions are expressed in natural language only, making it impossible to incorporate them into an automatic analysis tool. Furthermore, early understanding of how components call each other would be necessary, but it is currently difficult to achieve by means of a tool, as the method dispatch rules in a component system differ from the dispatch rules of the programming language(s) in which they were developed. We have developed a metamodel, , for describing boundary conditions, an analysis method, , and a static component-level call graph extraction method for EJB applications, CHA _EJB . uses models to analyze inter-component call graphs, and thus detect problems such as composition mismatches or redundancies, thus allowing for remedial action to take place. We present and CHA _EJB in this article, show that produces correct results, and describe a prototype analysis tool implementing the three, which we used to validate our approach on two popular EJB applications. The support of the Informatics Commercialisation initiative of Enterprise Ireland is gratefully acknowledged.     

Measures of localized spinal muscle fatigue

The objective of this study was to determine the best variable, if any, to indicate the level of localized muscle fatigue. Six male and six female subjects were studied while they exerted their maximal voluntary contraction and 40% of maximal voluntary contraction of spinal extensors in an isometric lifting activity. The electromyography (EMG) of erectores spinae at thoracic and lumbar levels was measured bilaterally. Also, the muscle bed blood volume, level of blood oxygenation to erector spinae at L3 level and heart rate were measured. The initial and final values of subjective feelings of fatigue through visual analogue score, rate of perceived exertions and body part discomfort rating were recorded. The mean maximal voluntary contraction forces for males and females were 899 (238) N and 431 (135) N respectively. The mean durations of hold in maximal voluntary fatiguing contraction were 68.1 (39.9) s and 72.3 (37.0) s for men and women respectively. By the end of the hold the force declined to 52% for males and 62% for females. The EMG amplitudes and median frequencies also progressively declined (p < 0.01). ANOVA revealed that the task percentile values of all variables were significantly different (p < 0.01). Gender had a significant main effect (p < 0.01). The correlation coefficients between force and other individual variables were weak to modest, but significant (p < 0.001). None of the single variables predicted fatigue reliably for either gender and levels of contraction. The regression equations developed were highly significant (p < 0.01) and they explained 96 to 98% of variance in both genders and contractions.