FreeForm: An informal environment for interface prototyping

Best practice in interface design suggests that hand-drawn sketches are preferable at the early stages of the design process. This paper describes the FreeForm software which supports informal sketched interface design by acting as a Visual Basic Add-In. The Software utilises a digital whiteboard and pen input to support sketching and “running” of an informal prototype

Evaluting a sketch environment for novice programmers

This paper describes the evaluation of an electronic sketch interface design tool for novice programmers. A comparative study was undertaken with small groups using two different shared space environments; a conventional informal design environment and the pen based digital whiteboard. The students reacted positively to the electronic environment, where they worked informally with their design ideas and checked them more carefully

Freeform: A Tool for Sketching Form Designs

This demonstration shows the tool we have developed for hand-sketching user interfaces. Our motivation for developing this tool is to provide an environment where novice programmers can move freely along the design continuum from informal low-fidelity prototypes to completed formal designs. A low-cost digital whiteboard is used to provide a shared work space for Freeform. The tool is integrated into a programming IDE and provides penbased sketching and editing, a storyboard, run mode, recognition of shapes and words and conversion into a formal design in the programming IDE

Design Details of FOCS-2, an Improved Continuous Cesium Fountain Frequency Standard

International audienceWe report on the design, construction and current status of FOCS-2, the second continuous fountain microwave cesium frequency standard after FOCS-1. Both incorporate velocity-selective light traps driven by an electrostatic motor. FOCS-2 will take fuller advantage of the continuous fountain approach to gain in shot-noise-limited stability without loss of accuracy via the use of a higher flux. This is obtained via the implementation of a novel slow-atom pre-source and better collimation of the atomic beam. A detailed description of the apparatus is provided and compared with FOCS-1 to highlight improvements. In addition, we present results from related experiments on collimation in a 2D optical lattice. The goals for this new standard are a short-term stability of < 4x10-14 $\tau$-1/2 and a relative frequency uncertainty of < 1 x 10-15

Acoustic thermometer operating up to 11 m: uncertainty assessment and new values for Cramer coefficients around 40 kHz

The present article describes an acoustic thermometer to measure the average air temperature integrated along a path ranging from 1 m to 11 m. It is based on time-of-flight measurement of ultrasound pulses at frequencies close to 40 kHz. Several methods for the detection of arrival times were investigated, notably cross-correlation and cross-spectrum. The uncertainty of the instrument itself, independent of that of the Cramer equation has been estimated at between 0.13 K to 0.09 K for distances ranging from 3 m to 11 m respectively. In practice, an experimental comparison with Pt100 probes (uncertainty of 0.1 K) has shown that the estimated uncertainty levels are relatively compatible, although the linearity of the system does not appear to be very good. To solve this problem, appropriate values for the Cramer coefficients a0 and a1 for an acoustic frequency of about 40 kHz have been determined, which contributes to improved knowledge of this equation as a function of acoustic frequency

Numerical and Experimental Study of the Hydrostatic Pressure Correction in Gas Thermometry: A Case in the SPRIGT

Single-pressure refractive index gas thermometry (SPRIGT) is a new type of primary thermometry, which needs an extremely stable working pressure (stability &lt; 4 ppm). In practice, the pressure control system at room temperature is located above the cold resonator at 5 K to 25 K, and a long pressure tube is used to connect them, which entails a hydrostatic pressure correction (HPC). To this end, a three-dimensional (3D) Computational Fluid Dynamics (CFD) simulation model of the pressure tube has been developed and compared with experimental results. First, to verify the simulation results, the helium-4 gas pressure in the center of the resonator was measured using a determination of the refractive index by microwave resonance coupled with the knowledge of the temperature. Results of simulation and experiment showed good agreement. Thereafter, based on this CFD simulation, the non-linear temperature distribution in the vertical pressure tube and the uncertainty caused by this non-linear phenomenon were calculated. After this, the validity of the isothermal assumption to simplify the calculation of the HPC was verified. Finally, the effect of heating on the pressure was studied and its impact found to be negligible. To the best of our knowledge, this is the first time experimental and simulation results have been compared for the HPC. The results are expected to be more generally applicable to the accurate determination of pressure in cryostats

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant