917 research outputs found

    The use of simulation in the design of a road transport incident detection algorithm

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    Automatic incident detection is becoming one of the core tools of urban traffic management, enabling more rapid identification and response to traffic incidents and congestion. Existing traffic detection infrastructure within urban areas (often installed for traffic signal optimization) provides urban traffic control systems with a near continuous stream of data on the state of traffic within the network. The creation of a simulation to replicate such a data stream therefore provides a facility for the development of accurate congestion detection and warning algorithms. This paper describes firstly the augmentation of a commercial traffic model to provide an urban traffic control simulation platform and secondly the development of a new incident detection system (RAID-Remote Automatic Incident Detection), with the facility to use the simulation platform as an integral part of the design and calibration process. A brief description of a practical implementation of RAID is included along with summary evaluation results

    Development of an Academic Risk Model to support Higher Education Quality Assurance

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    [EN] This paper presents a model of risk management in higher education, to support the quality assurance framework and the activities, more generally, of a Higher Education Institute. Its purpose is to define the Institute’s approach to academic risk and its management and to inform decision-making. Academic risk is defined and contextualized in terms of published literature. Decision-making and judgement is at the centre of all academic activities and accordingly inherent risk will always exist, through the exercise of judgement, the operation of academic policies and procedures and through compliance. A normative model of academic risk assessment is proposed, based on three levels: isolated academic risk, repeated academic risk and systemic academic risk. This is followed by a proposed model for action according to the level of risk. Finally the operation of the model in our higher education institute is presentedMcdonald, T.; O'byrne, D.; O'leary, P.; O'riordan, C. (2020). Development of an Academic Risk Model to support Higher Education Quality Assurance. En 6th International Conference on Higher Education Advances (HEAd'20). Editorial Universitat Politècnica de València. (30-05-2020):1323-1329. https://doi.org/10.4995/HEAd20.2020.11261OCS1323132930-05-202

    PRESSURE DROP EXPERIMENTS OF UPPER AND LOWER DUMMY ASSEMBLIES FOR THE EXPERIMENTAL GAS COOLED REACTOR. SECTION V OF THE FUEL ASSEMBLY HEAT TRANSFER AND CHANNEL PRESSURE DROP EXPERIMENTS FOR THE EGCR RESEARCH AND DEVELOPMENT PROGRAM

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    The design arrangement of the Experimental Gas Cooled Reactor contains six fuel assemblies stacked vertically, above one another, in each of 232 vertical fuel channels in the graphite core. Each stack of six fuel assemblies is preceded and followed by a dummy assembly. The upper dummy assembly contains a reflector plug and a latch mechanism. The lower dummy assembly contains an orifice with an adjustable plunger capable of varying reactor coolant flow through the orifice. The pressure drop characteristics of the dummy assemblies for eight different throttling positions were obtained in the test program at near atmospheric pressure using an air flow corresponding to Reynolds Numbers of 12,000 to 60,000 in the fuel element assemblies. The data of the tests are presented in the form of velocity head coefficients expressed in terms of the highest velocity head of the two test locations involved for each coefficient. (auth

    The Electronic Commerce Integrated Development Methodology For Small Firms

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    Electronic Commerce (EC) technologies have the ability to reshape industry structure, and in doing so modify the rules of competition, which, in turn, lead to new methods of competing (Thong, 1999; Hawkins et al., 1999). The technological shift from traditional methods to Internet-based methods of trading has facilitated cost and competitive advantage (Auger and Gallaugher, 1997). However, to maximise EC gains it is critical that organisations understand the phases of technological assimilation and also the managerial issues involved in implementing new technologies. This specifically requires a coherent and combined approach to EC technology deployment, Business Process Reengineering (BPR) and associated activities such as Organisational Learning (OL). Research conducted by Turban et al. (1999) indicates that Information Systems Development (ISD) can provide a stimulus for productivity and quality improvements, through process improvements, automation, and associated initiatives. It is therefore evident that there is a very close relationship between BPR and ISD. Furthermore, research reveals that many leading authors view Information Technology (IT) as being a critical enabler of BPR (Bartram, 1992; Davenport, 1993). Stoddard and Jarvenpaa (2000) believe that the absence of IT capabilities can be a major inhibitor to BPR. ..

    Glucocorticoid-induced polycystic kidney disease—A threshold trait

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    Glucocorticoid-induced polycystic kidney disease—A threshold trait. Administration of hydrocortisone acetate (250 mg/kg) to newborn mice caused polycystic kidney disease (PKD) of varying proportions in each of 18 different inbred strains; none of the injected controls were affected. All kidneys were histologically examined and scored for degree of cyst formation using a semi-continuous (0 to 4+) grading scheme. Results suggested that this condition is a multifactorial threshold trait. For each strain, estimates of the mean and standard deviation of normally distributed liability were determined by maximum likelihood methods. Concomitant analyses showed: 1) a significant environmental effect related to drug source; 2) a variation in thresholds ranging from 0.94 (N = 46) for the B10.M strain to -0.71 (N = 297) for the C57B1/6J strain; and 3) three groups of strains with different susceptibility to PKD. These results are consistent with a multifactorial basis for susceptibility to PKD. Quantitative analysis of thresholds and liability distributions reveals that genetic, environmental and random elements all contribute to the expression and extent of the cystic trait

    Cosmological Effects of Radion Oscillations

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    We show that the redshift of pressureless matter density due to the expansion of the universe generically induces small oscillations in the stabilized radius of extra dimensions (the radion field). The frequency of these oscillations is proportional to the mass of the radion and can have interesting cosmological consequences. For very low radion masses mbm_b (mb∼10−100H0≃10−32eVm_b\sim10-100 H_0\simeq10^{-32} eV) these low frequency oscillations lead to oscillations in the expansion rate of the universe. The occurrence of acceleration periods could naturally lead to a resolution of the coincidence problem, without need of dark energy. Even though this scenario for low radion mass is consistent with several observational tests it has difficulty to meet fifth force constraints. If viewed as an effective Brans-Dicke theory it predicts ω=−1+1D\omega=-1+\frac{1}{D} (DD is the number of extra dimensions), while experiments on scales larger than 1mm1mm imply ω>2500\omega>2500. By deriving the generalized Newtonian potential corresponding to a massive toroidally compact radion we demonstrate that Newtonian gravity is modified only on scales smaller than mb−1m_b^{-1}. Thus, these constraints do not apply for mb>10−3eVm_b>10^{-3} eV (high frequency oscillations) corresponding to scales less than the current experiments (0.3mm0.3mm). Even though these high frequency oscillations can not resolve the coincidence problem they provide a natural mechanism for dark matter generation. This type of dark matter has many similarities with the axion.Comment: Accepted in Phys. Rev. D. Clarifying comments added in the text and some additional references include

    Isolation and primary structure of human PHI (peptide HI)

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    AbstractThe isolation of the human form of PHI (peptide HI) is described. The peptide was purified from human colonic extracts by using a chemical method for the detection of its C-terminal amidated structure. Human PHI consists of 27 amino acid residues and the complete amino acid sequence is: His-Ala-Asp-Gly-Val-Phe-Thr-Ser-Asp-Phe-Ser-Lys-Leu-Leu-Gly-Gln-Leu-Ser-Ala-Lys-Lys-Tyr-Leu-Glu-Ser-Leu-Met-NH2. The differences between the structures of porcine and human PHI are at position 12 (Arg/Lys replacement) and at position 27 (Ile/Met).Human PHIPorcine PHIBovine PHIBrain peptideGut peptideC-terminal amideVIP/PHI precurso

    In-situ X-ray computed tomography characterisation of 3D fracture evolution and image-based numerical homogenisation of concrete

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    In-situ micro X-ray Computed Tomography (XCT) tests of concrete cubes under progressive compressive loading were carried out to study 3D fracture evolution. Both direct segmentation of the tomography and digital volume correlation (DVC) mapping of the displacement field were used to characterise the fracture evolution. Realistic XCT-image based finite element (FE) models under periodic boundaries were built for asymptotic homogenisation of elastic properties of the concrete cube with Young’s moduli of cement and aggregates measured by micro-indentation tests. It is found that the elastic moduli obtained from the DVC analysis and the FE homogenisation are comparable and both within the Reuss-Voigt theoretical bounds, and these advanced techniques (in-situ XCT, DVC, micro-indentation and image-based simulations) offer highly-accurate, complementary functionalities for both qualitative understanding of complex 3D damage and fracture evolution and quantitative evaluation of key material properties of concrete

    Morphology and foliar chemistry of containerized Abies fraseri (Pursh) Poir. seedlings as affected by water availability and nutrition

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    • We present the results of a two-year (2007–2008) greenhouse study investigating the effect of water availability and nitrogen fertilization on the growth, biomass partitioning, and foliar nutrient content of Abies fraseri (Pursh) Poir. • Fertilizer and moisture content (irrigation) were varied in a factorial experiment combining four levels of irrigation and three levels of fertilization to evaluate growth and foliar nutrient content. In addition, a numerical optimization was used to estimate appropriate levels of each factor necessary to achieve simulated goals for response variables. • Irrigation increased the height growth by 12 to 35% depending on the fertilization treatment (p = 0.0001). Fertilization increased height growth by 10 to 26% (p = 0.02). A similar response was observed for stem diameter growth (SDG). Total biomass accumulation increased as result of positive response of stem and root biomass development, and foliar nitrogen content was positively affected by nitrogen fertilization and negatively affected by irrigation. The numerical optimization for simulated target growth and nitrogen content responses produced levels of input combinations with high desirability factors to achieve the target responses. • These results suggest that nutrient addition is a strong determining factor for early development of this species. The improved growth efficiency in this study is likely attributed to a combination of factors including, improved photosynthetic capacity, decreased stomatal limitations, or increased resource allocation to stems
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