1,030 research outputs found

    Schedulability analysis of timed CSP models using the PAT model checker

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    Timed CSP can be used to model and analyse real-time and concurrent behaviour of embedded control systems. Practical CSP implementations combine the CSP model of a real-time control system with prioritized scheduling to achieve efficient and orderly use of limited resources. Schedulability analysis of a timed CSP model of a system with respect to a scheduling scheme and a particular execution platform is important to ensure that the system design satisfies its timing requirements. In this paper, we propose a framework to analyse schedulability of CSP-based designs for non-preemptive fixed-priority multiprocessor scheduling. The framework is based on the PAT model checker and the analysis is done with dense-time model checking on timed CSP models. We also provide a schedulability analysis workflow to construct and analyse, using the proposed framework, a timed CSP model with scheduling from an initial untimed CSP model without scheduling. We demonstrate our schedulability analysis workflow on a case study of control software design for a mobile robot. The proposed approach provides non-pessimistic schedulability results

    Dynamic point-region quadtrees for particle simulations

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    Cataloged from PDF version of article.We propose an algorithm for dynamically updating point-region (PR) quadtrees. Our algorithm is optimized for simultaneous update of data points comprising a quadtree. The intended application area focuses on simulating continuum phenomena, such as crowds, fluids, and smoke. We minimize the number of tree updates by making use of small changes in the positions of data points. We compare the efficiency of the proposed algorithm with two other approaches for updating a quadtree. One of these techniques creates the tree from scratch at each time-step. The second technique subsequently deletes a data point from the tree and reinserts it in its updated position. We achieve significant performance gains with our method in both cases. (C) 2012 Elsevier Inc. All rights reserved

    X-Chromosomal short tandem repeat loci in the Turkish population

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    In this study, we aimed to demonstrate the importance and utility of polymorphic short tandem repeat (STR) found on the human X chromosome and to provide the first allelic frequency data of X-STR (X chromosomal) loci in the Turkish population. Blood samples were taken from unrelated individuals (135 males and 129 females) from different regions of the country. Primers were designed according to gene bank data (www.gdb.org) and synthesised by the Köln Blutgruppen Institute. The primers amplified the following loci on the X chromosome: DXS8377, DXS101, DXS6789, STRX-1 and HUMHPRTB. Our data showed that two loci, DXS8377 and DX101, had the highest number of alleles (18) and the polymorphism information content (PIC) values of these loci were 0.9 and 0.87, respectively and were higher than those of other loci. In the other loci examined, 11 (STRX1), 10 (DXS6789) and 9 (HPRTB) alleles were detected and the PIC values of these loci were 0.78, 0.68 and 0.70, respectively. The highest (0.899) and lowest (0.674) rate of heterozygosity was found in the DXS8377 and HPRTB loci, respectively. In all loci, the power of discrimination for female (PDF) values were higher than the power of discrimination for male (PDM) values. The locus with the highest PDF value was DXS8377 (0.9841). The mean exclusion change (MEC) value of this locus also proved to be the highest for both fathermother- child and father-child. The locus with the lowest MEC value was DXS6789. To use calculations of probabilities of genetic results for forensic purposes, allelic frequencies in individuals in the community should be determined. Our study provides the first data from the Turkish population.Key words: X chromosomal (X-STR), forensic genetics, forensic sciences, DNA, kinship testing, paternity

    The Effect of Lowered Tire Pressure on a Log Truck Driver Seat

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    Adjusting truck tire inflation to changing road and load conditions has been demonstrated to improve road conditions and is thought to decrease truck maintenance costs. Good roads will minimize the future cost of utilizing forest resources. In this study, the various effects of both low-pressure and high-pressure truck tires on the transportation vehicle were examined in terms of seat vibration. The data collected by the US Army Corps of Engineers, Waterways Experiment Station (WES), for the USDA Forest Service in 1989, were used to perform the analyses. Analysis of the data pertaining to road failure is fairly complete. However, a significant portion of the truck data still needs to be analyzed. Vibration levels were higher in the truck with high tire-inflation pressure, but the differences in vibration levels between low- and high-pressure trucks were not as high as expected. Although vibration levels were higher in 10 out of 15 road sections in the high-pressure truck, two sections had significantly reversed results

    High Power CMUTs: Design and experimental verification

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    Cataloged from PDF version of article.Capacitive micromachined ultrasonic transducers (CMUTs) have great potential to compete with piezoelectric transducers in high-power applications. As the output pressures increase, nonlinearity of CMUT must be reconsidered and optimization is required to reduce harmonic distortions. In this paper, we describe a design approach in which uncollapsed CMUT array elements are sized so as to operate at the maximum radiation impedance and have gap heights such that the generated electrostatic force can sustain a plate displacement with full swing at the given drive amplitude. The proposed design enables high output pressures and low harmonic distortions at the output. An equivalent circuit model of the array is used that accurately simulates the uncollapsed mode of operation. The model facilities the design of CMUT parameters for high-pressure output, without the intensive need for computationally involved FEM tools. The optimized design requires a relatively thick plate compared with a conventional CMUT plate. Thus, we used a silicon wafer as the CMUT plate. The fabrication process involves an anodic bonding process for bonding the silicon plate with the glass substrate. To eliminate the bias voltage, which may cause charging problems, the CMUT array is driven with large continuous wave signals at half of the resonant frequency. The fabricated arrays are tested in an oil tank by applying a 125-V peak 5-cycle burst sinusoidal signal at 1.44 MHz. The applied voltage is increased until the plate is about to touch the bottom electrode to get the maximum peak displacement. The observed pressure is about 1.8 MPa with −28 dBc second harmonic at the surface of the array

    The measurement of membranous urethral length using transperineal ultrasound prior to radical prostatectomy

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    Objective: To compare preoperative membranous urethral length (MUL) measurements using magnetic resonance imaging (MRI) with two-dimensional transperineal ultrasound imaging (TPUS) in two supine positions on two separate days in men prior to radical prostatectomy. Materials and methods: MUL was prospectively measured in 18 male volunteers using MRI and on two separate occasions in two different patient positions using TPUS; the patient supine with the knees extended (Supine) and supine with the knees flexed to 70 degrees (Supine KF). Agreement between TPUS and MRI measurements of MUL was assessed using Bland-Altman method comparison techniques and a two-way mixed-effects single measures intraclass correlation (ICC). Test-retest reliability was assessed using a two-way random effects single measures ICC. Results: The mean difference in MUL measurements between MRI and i) TPUS Supine was -0.8 mm (95% limits of agreement (LOA): -3.2, 1.7) and ii) TPUS Supine KF was -0.8mm (95% LOA: -3.5, 1.9). ICC indicated a point estimate of excellent agreement between MRI and TPUS Supine ICC 0.93 (95% CI: 0.76, 0.98) and TPUS Supine KF ICC 0.91 (95 0 /0CI 0.79, 0.97). There was excellent agreement between TPUS Supine and TPUS Supine KF (ICC 0.98, 95% CI: 0.96, 0.99) with a mean difference of 0.3mm (95% LOA: -1.2 to 1.3mm). Conclusions: Preoperative MUL can be reliably measured using TPUS and demonstrates excellent agreement with MRI measurements of MUL. TPUS provides clinicians with an accessible non-invasive alternative to MRI for the measurement of MUL that can be used in outpatient urological settings and for patients where MRI is contraindicated

    Scaling and super-universality in the coarsening dynamics of the 3d random field Ising model

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    We study the coarsening dynamics of the three-dimensional random field Ising model using Monte Carlo numerical simulations. We test the dynamic scaling and super-scaling properties of global and local two-time observables. We treat in parallel the three-dimensional Edward-Anderson spin-glass and we recall results on Lennard-Jones mixtures and colloidal suspensions to highlight the common and different out of equilibrium properties of these glassy systems.Comment: 18 pages, 21 figure
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