917 research outputs found
The use of simulation in the design of a road transport incident detection algorithm
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
[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 Instituteâs 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
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
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 diseaseâA threshold trait
Glucocorticoid-induced polycystic kidney diseaseâA 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
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 () 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
( is the number of extra dimensions), while
experiments on scales larger than imply . 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 . Thus, these constraints do not apply for
(high frequency oscillations) corresponding to scales less than the current
experiments (). 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)
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
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 Youngâs 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
Governing infrastructure networks for a low carbon economy:co-evolution of technologies and institutions in UK electricity distribution networks
Morphology and foliar chemistry of containerized Abies fraseri (Pursh) Poir. seedlings as affected by water availability and nutrition
⢠We present the results of a two-year (2007â2008) 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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