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The data/timing formatter is a key module in automatic electronics test equipment; it formats the test data to the desired wave shape and places the timing edges at the designated locations. In this work, we investigate the design and implementation of the FPGA-based data/timing formatter. Compared to its ASIC counterpart, the FPGA-based formatter is more flexible because it can be reconfigured to best fit the target test specifications. However, routing uncertainty and limited types of available logic and interconnect resources also pose great challenges. This work proposes a formatter design that is suitable for FPGA implementation. Several high-linearity FPGA-based programmable delay lines are developed. According to its characteristics, each type of delay lines is assigned a different role in the formatter. The formatter is also equipped with a calibration unit to further improve the edge placement resolution and accuracy. A 100-Msps FPGA-based data/timing formatter with 20-ps edge placement resolution has been implemented on an FPGA development board to validate our ideas.

With modern FPGAs' reconfiguration flexibility and abundant resources, FPGA-based test equipment has become a promising solution for low to mid-end test and measurement applications. However, FPGA structure and specifications limit the choice of tester architecture and achievable performance. In this paper, we design and implement an FPGA-based multi-channel data/timing formatter, a key component in automatic test equipment. The proposed formatter (1) adopts the EG (edge generator) pool concept to improve hardware utilization, (2) employs accuracy-driven EG scheduling to improve edge placement accuracy, (3) embeds a delay monitor for temperature compensation, and (4) allows inter-channel skew adjustment. A prototype five-channel formatter is implemented on Xilinx Spartan-6 FPGA. The per channel symbol rate is 100 Msps and the edge placement resolution is 200 ps.

In designing intersection signal timing plans transportation professionals have to account for two main objectives that often times are antagonistic: to ensure good flow of traffic and to maintain a high level of safety for all road users. Although the two objectives do not necessarily exclude one another, identifying the compromise that provides the best traffic and safety conditions for all road users is not a straightforward exercise. In this study, the authors propose a methodology that can be used to determine the best signal timing of urban intersections by reaching a desired equilibrium between the two objectives. The methodology is using a combined delay-safety (DS) performance measure in an artificial intelligence decision-making framework. A case study of an urban arterial with a newly built bicycle path in downtown Montreal, Quebec, was investigated using a microscopic traffic simulator, VISSIM. A multilayer perceptron (MLP) neural-network uses several traffic flow parameters as input informati...

Summary Background: First, fir st permanent molars (FPMs) of poor prognosis are often planned for extraction at an 'ideal time' so that second permanent molars (SPMs) erupt favourably to replace them. However for lower FPM extractions, timing is not an accurate predictor of success. Objective: The aim of this study was to identify additional radiographic factor s that could better predict the degree of spontaneous space closure of the lower SPM following FPM extraction. Methods: Data from a previous study of 127 lower SPMs from 66 patients w as re-analysed by incorporating additional radiographic factors. These included calcification stage of the bifurcation of the SPM, position of the second premolar, mesial angulation of SPM in relation to the FPM, and presence of the third permanent molar. Results were analysed using ordered logistic regression. Results: Only 58 per cent of FPMs extracted at the 'ideal time' (SPM development at Demirjian stage E) had complete space closure. The best outcomes resulted from a combination of SPMs not at Demirjian development stage G, together with the presence of mesial angulation of the SPM and presence of the third permanent molar, where 85 per cent of those cases had complete space closure. Conclusions: Apart from extraction timing of the FPM, consideration must also be gi ven to the presence of the third permanent molar and angulation of the SPM in order to ensure a reliable degree of spontaneous space closure of the lower SPM.

The aim of this study was to investigate the in vivo and in vitro validity of International Caries Detection and Assessment System (ICDAS), DIAGNOdent pen and CarieScan PRO in the detection and assessment of occlusal caries in primary teeth. Sixty-four molars were assessed using all three systems under standardised in vivo conditions. They were then extracted and assessed by two examiners in vitro along with an additional 38 teeth (102 teeth in total from 45 children). Downer’s histological scoring criterion was the validation gold standard. Sensitivity, specificity, positive and negative likelihood ratios and area under the receiver–operator curves were calculated for all caries and dentine caries. Repeatability was analysed using Cohen’s Kappa and the performance of the systems between in vivo and in vitro settings by the same examiner were compared. ICDAS showed the highest validity and repeatability. The DIAGNOdent pen’s overall clinical validity was comparable to that of ICDAS, but it demonstrated only moderate repeatability. CarieScan PRO had negligible validity in vivo, and there was no relationship between in vivo and in vitro parameters. The in vivo results of ICDAS and DIAGNOdent pen were satisfactory and comparable to those obtained in vitro, with ICDAS performing better. The CarieScan PRO performed poorly under both conditions. ICDAS should be the index of choice when detecting and assessing occlusal caries in the primary dentition, and in vitro data can be safely extrapolated in vivo. The DIAGNOdent pen must be employed with caution. Currently, the CarieScan PRO is unsuitable for use in the primary dentition.