73,584 research outputs found

    The practice of risk management by cost consultants in Northern Ireland

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    This research endeavoured to explore the practice of risk management by cost consultants in Northern Ireland. It attempted to subjectively investigate the cost consultant’s appreciation of risk management practices and then further appraise the cost consultant’s understanding and usage of the theories and techniques available to manage risk under the risk management framework. A case study based approach involving five consultancy practices was adopted. A series of semi structured interviews (one per each case study) was carried out. The data collected was analysed using the Delphi technique. The practice of risk management for each organisation was documented using an analysis and evaluation of project documentation substantiated with interviews. The research indicated that consultants have a broad awareness of risk management but disparity exists on considering it as a core service. All consultants were unequivocal in identifying the need for an improved risk management framework. It was evident that there was a lack of knowledge of the array of risk identification and analysis techniques available. The research has established that there is a severe need to bridge the void between the theories and techniques used to manage risk and those which are implemented in practice. There is a necessity to train consultants in the practice of risk management and educate clients in the benefits of enforcing risk management practices as an integral part of project delivery

    Zappa-Sz\'ep products of Garside monoids

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    A monoid KK is the internal Zappa-Sz\'ep product of two submonoids, if every element of KK admits a unique factorisation as the product of one element of each of the submonoids in a given order. This definition yields actions of the submonoids on each other, which we show to be structure preserving. We prove that KK is a Garside monoid if and only if both of the submonoids are Garside monoids. In this case, these factors are parabolic submonoids of KK and the Garside structure of KK can be described in terms of the Garside structures of the factors. We give explicit isomorphisms between the lattice structures of KK and the product of the lattice structures on the factors that respect the Garside normal forms. In particular, we obtain explicit natural bijections between the normal form language of KK and the product of the normal form languages of its factors.Comment: Published versio

    The Small and Large Time Implied Volatilities in the Minimal Market Model

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    This paper derives explicit formulas for both the small and large time limits of the implied volatility in the minimal market model. It is shown that interest rates do impact on the implied volatility in the long run even though they are negligible in the short time limit.Comment: 50 pages, 4 figures, typo on page 18 correcte

    Radio Galaxy Zoo: Knowledge Transfer Using Rotationally Invariant Self-Organising Maps

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    With the advent of large scale surveys the manual analysis and classification of individual radio source morphologies is rendered impossible as existing approaches do not scale. The analysis of complex morphological features in the spatial domain is a particularly important task. Here we discuss the challenges of transferring crowdsourced labels obtained from the Radio Galaxy Zoo project and introduce a proper transfer mechanism via quantile random forest regression. By using parallelized rotation and flipping invariant Kohonen-maps, image cubes of Radio Galaxy Zoo selected galaxies formed from the FIRST radio continuum and WISE infrared all sky surveys are first projected down to a two-dimensional embedding in an unsupervised way. This embedding can be seen as a discretised space of shapes with the coordinates reflecting morphological features as expressed by the automatically derived prototypes. We find that these prototypes have reconstructed physically meaningful processes across two channel images at radio and infrared wavelengths in an unsupervised manner. In the second step, images are compared with those prototypes to create a heat-map, which is the morphological fingerprint of each object and the basis for transferring the user generated labels. These heat-maps have reduced the feature space by a factor of 248 and are able to be used as the basis for subsequent ML methods. Using an ensemble of decision trees we achieve upwards of 85.7% and 80.7% accuracy when predicting the number of components and peaks in an image, respectively, using these heat-maps. We also question the currently used discrete classification schema and introduce a continuous scale that better reflects the uncertainty in transition between two classes, caused by sensitivity and resolution limits

    The Spectral Energy Distribution of Powerful Starburst Galaxies I: Modelling the Radio Continuum

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    We have acquired radio continuum data between 70\,MHz and 48\,GHz for a sample of 19 southern starburst galaxies at moderate redshifts (0.067<z<0.2270.067 < z < 0.227) with the aim of separating synchrotron and free-free emission components. Using a Bayesian framework we find the radio continuum is rarely characterised well by a single power law, instead often exhibiting low frequency turnovers below 500\,MHz, steepening at mid-to-high frequencies, and a flattening at high frequencies where free-free emission begins to dominate over the synchrotron emission. These higher order curvature components may be attributed to free-free absorption across multiple regions of star formation with varying optical depths. The decomposed synchrotron and free-free emission components in our sample of galaxies form strong correlations with the total-infrared bolometric luminosities. Finally, we find that without accounting for free-free absorption with turnovers between 90 to 500\,MHz the radio-continuum at low frequency (ν<200\nu < 200\,MHz) could be overestimated by upwards of a factor of twelve if a simple power law extrapolation is used from higher frequencies. The mean synchrotron spectral index of our sample is constrained to be α=1.06\alpha=-1.06, which is steeper then the canonical value of 0.8-0.8 for normal galaxies. We suggest this may be caused by an intrinsically steeper cosmic ray distribution

    Investigating the status of disaster management within a world-wide context: a case study analysis

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    Disasters can be described as feats of spontaneous occurrences, in that they can happen at any minute at any time. There are two classifications of disasters, which are, natural disasters that cannot be predicted and continuously occur throughout society. While the other classification of disaster is that of man-made disasters, where disasters are caused not by natural phenomena, but by man's or society's actions, involuntary or voluntary, sudden or slow, with grave consequences to the population and the environment (Hays, 2008). Both these types of disasters can be controlled to a certain extent through appropriate disaster management plans and if managed efficiently have the potential to reduce the likelihood of overwhelming loss of lives and property. The Disaster Management cycle is split into four elements of response, recovery, mitigation and preparedness which contribute to emergency protocols of a nation when disaster strikes. Therefore, nations should incorporate them in their development plans and ensure efficient follow-up measures at community, national and international levels. This paper investigates worldwide disasters in order to examine how these disasters were managed and to identify the lessons learned. It provides an analysis of five worldwide case studies of recent disasters (Tsunami in Sri Lanka, Hurricane Katrina in New Orleans, Earthquake in Pakistan, Summer floods in the UK and Flooding of the West-Link in Northern Ireland) mapping those to the four staged disaster management cycle. The paper analyses in detail the strategies adopted at each stage of the cycle comparing strengths and weaknesses of each case. It concludes that there had been satisfactory progress in both response and recovery phases but more attention is needed for disaster mitigation and preparedness

    Enhancing Parent-Child Communication and Parental Self-Esteem With a Video-Feedback Intervention: Outcomes With Prelingual Deaf and Hard-of-Hearing Children

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    Evidence on best practice for optimizing communication with prelingual deaf and hard-of-hearing (DHH) children is lacking. This study examined the effect of a family-focused psychosocial video intervention program on parent–child communication in the context of childhood hearing loss. Fourteen hearing parents with a prelingual DHH child (Mage = 2 years 8 months) completed three sessions of video interaction guidance intervention. Families were assessed in spontaneous free play interactions at pre and postintervention using the Emotional Availability (EA) Scales. The Rosenberg Self-esteem Scale was also used to assess parental report of self-esteem. Compared with nontreatment baselines, increases were shown in the EA subscales: parental sensitivity, parental structuring, parental nonhostility, child responsiveness, and child involvement, and in reported self-esteem at postintervention. Video-feedback enhances communication in families with prelingual DHH children and encourages more connected parent–child interaction. The results raise implications regarding the focus of early intervention strategies for prelingual DHH children

    Dance training shapes action perception and its neural implementation within the young and older adult brain

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    How we perceive others in action is shaped by our prior experience. Many factors influence brain responses when observing others in action, including training in a particular physical skill, such as sport or dance, and also general development and aging processes. Here, we investigate how learning a complex motor skill shapes neural and behavioural responses among a dance-naïve sample of 20 young and 19 older adults. Across four days, participants physically rehearsed one set of dance sequences, observed a second set, and a third set remained untrained. Functional MRI was obtained prior to and immediately following training. Participants’ behavioural performance on motor and visual tasks improved across the training period, with younger adults showing steeper performance gains than older adults. At the brain level, both age groups demonstrated decreased sensorimotor cortical engagement after physical training, with younger adults showing more pronounced decreases in inferior parietal activity compared to older adults. Neural decoding results demonstrate that among both age groups, visual and motor regions contain experience-specific representations of new motor learning. By combining behavioural measures of performance with univariate and multivariate measures of brain activity, we can start to build a more complete picture of age-related changes in experience-dependent plasticity

    Flux density measurements for 32 pulsars in the 20 cm band

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    Flux density measurements provide fundamental observational parameters that describe a pulsar. In the current pulsar catalogue, 27% of radio pulsars have no flux density measurement in the 20 cm observing band. Here, we present the first measurements of the flux densities in this band for 32 pulsars observed using the Parkes radio telescope and provide updated pulse profiles for these pulsars. We have used both archival and new observations to make these measurements. Various schemes exist for measuring flux densities. We show how the flux densities measured vary between these methods and how the presence of radio-frequency-interference will bias flux density measurementsComment: Accepted by RA

    Artificial neural networks for selection of pulsar candidates from the radio continuum surveys

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    Pulsar search with time-domain observation is very computationally expensive and data volume will be enormous with the next generation telescopes such as the Square Kilometre Array. We apply artificial neural networks (ANNs), a machine learning method, for efficient selection of pulsar candidates from radio continuum surveys, which are much cheaper than time-domain observation. With observed quantities such as radio fluxes, sky position and compactness as inputs, our ANNs output the "score" that indicates the degree of likeliness of an object to be a pulsar. We demonstrate ANNs based on existing survey data by the TIFR GMRT Sky Survey (TGSS) and the NRAO VLA Sky Survey (NVSS) and test their performance. Precision, which is the ratio of the number of pulsars classified correctly as pulsars to that of any objects classified as pulsars, is about 96%\%. Finally, we apply the trained ANNs to unidentified radio sources and our fiducial ANN with five inputs (the galactic longitude and latitude, the TGSS and NVSS fluxes and compactness) generates 2,436 pulsar candidates from 456,866 unidentified radio sources. These candidates need to be confirmed if they are truly pulsars by time-domain observations. More information such as polarization will narrow the candidates down further.Comment: 11 pages, 13 figures, 3 tables, accepted for publication in MNRA
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