Verification of a Radio-Based Signaling System Using the STATEMATE Verification Environment

With the trend to partially move safety-related features from courtyards into on-board control software, new challenges arise in supporting such designs by formal verification capabilities, essentially entailing the need for a model-based design process. This paper reports on the usage of the STATEMATE Verification Environment to model and verify a radio-based signaling system, a trial case study offered by the German train system company DB. It shows, that industrially sized applications can be modeled and verified with a verification tool to be offered as a commercial product by I-Logix, Inc.     

Task Demands Control Acquisition and Storage of Visual Information.

Attention and working memory limitations set strict limits on visual representations, yet researchers have little appreciation of how these limits constrain the acquisition of information in ongoing visually guided behavior. Subjects performed a brick sorting task in a virtual environment. A change was made to 1 of the features of the brick being held on about 10% of trials. Rates of change detection for feature changes were generally low and depended on the pick-up and put-down relevance of the feature to the sorting task. Subjects' sorting decision suggests that changes may be missed because of a failure to update the changed feature. The authors also explore how hand and eye behavior are coordinated for strategic acquisition and storage of visual information throughout the task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anti-scattering X-ray grid

 Various optical or x-ray applications require reduction of scattered radiation on the imaging detector to produce sharper images. The scattered radiation is reduced when the radiation impacting on the detector is from a chosen small solid angle. This requires a mask in front of the detector with small holes and high aspect ratio. We are applying the SLIGA process to perform a proof-of-principle demonstration with the capability of making a large and high area anti-scattering grid. The approach is by assembling and stacking small pieces of grid. To maintain high throughput of the desired radiation, the wall of the grid has to be thin. We designed and fabricated four grid patterns all with 20 μm thick walls and 80 μm×80 μm holes. The individual pieces were 210 μm high and made of nickel. The pieces were assembled and stacked to make a 5 mm×5 mm grid 2.1 mm high. Much larger grids can be made by the SLIGA process, which was chosen because of its capability to fabricate high aspect ratio devices with precision. Received: 25 August 1997/Accepted: 24 October 1997     

Analysis of New Nitinol Ingot Qualities

New ingot qualities, processed by optimized vacuum arc remelting (VAR), optimized vacuum induction melting followed by VAR and VAR followed by electron beam remelting, were compared with standard quality. Finished components as well as diamond-shaped samples representing a typical dimension of self-expanding stents were produced using Nitinol tubing drawn from the new ingot qualities. Metallographic longitudinal sections were prepared and analyzed to determine inclusion size and distributions of the various ingot qualities. Radial force and uniaxial tensile tests were used to determine the mechanical properties of fully processed material and tubing, respectively. Transformation temperatures of tubing as delivered from supplier and processed stents were measured by differential scanning calorimetry and deformation-and-free-recovery testing. Finally, fatigue tests were performed on diamond-shaped samples to evaluate the strain-life characteristics of the new ingot qualities. Results of this study are compared to ADMEDES historical data from standard Nitinol materials to gain an assessment of the new improved ingot qualities with regard to the production of Nitinol vascular implants. The latest developments in Nitinol ingot quality are highlighted and the results of the comparison from technical point of view are shown.