Data-Driven Generalized Integer Aperture Bootstrapping for Real-Time High Integrity Applications

A new method is developed for integer ambiguity resolution in carrier-phase differential GPS (CDGPS) positioning. The method is novel in that it is (1) data-driven, (2) generalized to include partial ambiguity resolution, and (3) amenable to a full characterization of the prior and posterior distributions of the three-dimensional baseline vector that results from CDGPS. The technique is termed generalized integer aperture bootstrapping (GIAB). GIAB improves the availability of integer ambiguity resolution for high-integrity, safety-critical systems. Current high-integrity CDGPS algorithms, such as EPIC and GERAFS, evaluate the prior risk of position domain biases due to incorrect integer ambiguity resolution without further validation of the chosen solution. This model-driven approach introduces conservatism which tends to reduce solution availability. Common data-driven ambiguity validation methods, such as the ratio test, control the risk of incorrect ambiguity resolution by shrinking an integer aperture (IA), or acceptance region. The incorrect fixing risk of current IA methods is determined by functional approximations that are inappropriate for use in safety-of-life applications. Moreover, generalized IA (GIA) methods incorrectly assume that the baseline resulting from partial ambiguity resolution is zero mean. Each of these limitations is addressed by GIAB, and the claimed improvements are validated by Monte Carlo simulation. The performance of GIAB is then optimized by tuning the integer aperture size to maximize the prior probability of full ambiguity resolution. GIAB is shown to provide higher availability than EPIC for the same integrity requirements.Aerospace Engineering and Engineering Mechanic

High-order noise filtering in nontrivial quantum logic gates

Treating the effects of a time-dependent classical dephasing environment during quantum logic operations poses a theoretical challenge, as the application of non-commuting control operations gives rise to both dephasing and depolarization errors that must be accounted for in order to understand total average error rates. We develop a treatment based on effective Hamiltonian theory that allows us to efficiently model the effect of classical noise on nontrivial single-bit quantum logic operations composed of arbitrary control sequences. We present a general method to calculate the ensemble-averaged entanglement fidelity to arbitrary order in terms of noise filter functions, and provide explicit expressions to fourth order in the noise strength. In the weak noise limit we derive explicit filter functions for a broad class of piecewise-constant control sequences, and use them to study the performance of dynamically corrected gates, yielding good agreement with brute-force numerics.Comment: Revised and expanded to include filter function terms beyond first order in the Magnus expansion. Related manuscripts available from http://www.physics.usyd.edu.au/~mbiercu

Latent image diffraction from submicron photoresist gratings

Light scattering from latent images in photoresist is useful for lithographic tool characterization, process monitoring, and process control. In particular, closed‐loop control of lithographic processes is critical for high yield, low cost device manufacturing. In this work, we report use of pulsed laser diffraction from photoresist latent images in 0.24 μm pitch distributed feedback laser gratings. Gated detection of pulsed light scattering permits high spatial resolution probing using ultraviolet light without altering the latent image. A correlation between latent image and etched grating diffraction efficiencies is demonstrated and shows the value of "upstream" monitoring

Enzymatic breakage of dimethylsulfoniopropionate - a signature molecule for life at sea

Largely using gene-based evidence, the last few years have seen real insights on the diverse ways in which different microbes break down dimethylsulfoniopropionate, an abundant anti-stress molecule that is made by marine algae, some corals and a few angiosperms. Here, we review more recent advances in which in vitro biochemical tools – including structural determinations – have shed new light on how the corresponding enzymes act on DMSP. These have revealed how enzymes in very different polypeptide families can act on this substrate, often by novel ways, and with broader implications that extend from enzymatic mechanisms to microbial ecology

Pulse plating of copper from deep eutectic solvents

The effect of pulse parameters on the deposition of copper from a chloride-based deep eutectic solvent (DES) was investigated. While satisfactory deposits could be obtained for some pulse conditions, at small duty cycles or long off-times the current efficiencies obtained were very low. These findings were consistent with a corrosion process occurring during the off-time, most likely the comproportionation reaction: Cu + CuIICl4 2- → 2CuICl2 - . Initial experimental results were consistent with the corrosion rate being controlled by the transport of the CuIICl4 2- species to the electrode surface. With this assumption, a simple corrosion model was developed to account for the observed loss in current efficiency as a function of the pulse conditions. While this model broadly predicts the observed results some discrepancy between the observed and measured were noted

Copper electrodeposition from a water-containing choline chloride based deep eutectic solvent

This study investigated the effect of water on the physical and electrochemical properties of a choline chloride deep eutectic solvent (DES). Physical and electrochemical measurements were performed on the DES containing varying amounts of water. When the water content was increased from 1% to 15 wt%, the viscosity and density declined while the conductivity increased significantly. Similarly, the limiting current for Cu reduction at 15 wt% of water was also found to be three times greater than the limiting current at 1 wt% of water. This latter effect could be mostly attributed to viscosity changes, but there was evidence of deviations from ideal Stokes-Einstein behaviour. These experimental results show that inclusion of water facilitates ion mobility, and generally results in improved electrochemical characteristics

Giving the Gift of Goodness: An Exploration of Socially Responsible Gift-Giving

Previous research demonstrates that consumers support firms' CSR activities, and increasingly demand socially responsible products and services. However, an implicit assumption in the extant literature is that the purchaser and the consumer of the product are the same person. The current research focuses on a unique form of socially responsible consumption behavior: gift-giving. Through 30 depth consumer interviews, we develop a typology of consumers based on whether consumers integrate CSR-related information into purchases, and whether the purchases are for themselves or for others (i.e., gifts). We find that in some instances, consumers actively avoid purchasing products from socially responsible organizations and do so with the intention of managing their impressions with the gift recipient. This is counter to previous research that suggests consumers often choose to make socially responsible consumption decisions in efforts to satisfy self-presentation concerns. In addition, the decision to engage in socially responsible consumption for oneself but not for others was motivated by a variety of factors including the role of the recipient and a concern over the credibility of socially responsible gifts. Finally, some participants who do not incorporate CSR into their own personal consumption chose gifts based on a variety of CSR activities in an effort to build awareness for socially responsible organizations

Robustness of composite pulses to time-dependent control noise

We study the performance of composite pulses in the presence of time-varying control noise on a single qubit. These protocols, originally devised only to correct for static, systematic errors, are shown to be robust to time-dependent non-Markovian noise in the control field up to frequencies as high as ~10% of the Rabi frequency. Our study combines a generalized filter-function approach with asymptotic dc-limit calculations to give a simple analytic framework for error analysis applied to a number of composite-pulse sequences relevant to nuclear magnetic resonance as well as quantum information experiments. Results include examination of recently introduced concatenated composite pulses and dynamically corrected gates, demonstrating equivalent first-order suppression of time-dependent fluctuations in amplitude and/or detuning, as appropriate for the sequence in question. Our analytic results agree well with numerical simulations for realistic $1/f$ noise spectra with a roll-off to $1/f^2$, providing independent validation of our theoretical insights.Comment: 11 pages, 4 figures, text and figures updated to published versio

The role of culture and diversity in the prevention of falls among older Chinese people

Original article can be found at : http://journals.cambridge.org/ Copyright Canadian Association on GerontologyThis grounded-theory study explored the perceptions of Chinese older people, living in England, on falls and fear of falling, and identified facilitators and barriers to fall prevention interventions. With a sample of 30 Chinese older people, we conducted two focus groups and 10 in-depth interviews in Mandarin or Cantonese. Interview transcripts, back translated, were analyzed using N6. Constant comparative analysis highlighted a range of health-seeking behaviors after a fall: Chinese older people were reluctant to use formal health services; talking about falls was avoided; older people hid falls from their adult children to avoid worrying them; and fatalistic views about falls and poor knowledge about availability and content of interventions were prevalent. Cost of interventions was important. Chinese older adults valued their independence, and cultural intergenerational relations had an impact on taking action to prevent falls. Cultural diversity affects older adults’ acceptance of fall prevention interventions.Peer reviewe