3,827 research outputs found
Automated ubiquitos delivery of generalised services in a open market
University of Technology, Sydney. Faculty of Information Technology.Telecommunications networks, and the services delivered over those networks have become an integral part of most people's lives in the developed world. The range and availability of these services is increasing, however the management of services still lags well behind technical capability, providing unnecessary barriers to the adoption of available technology. The work described in this dissertation has a primary goal of enabling flexible, automated delivery of any telecommunication-based service. More specifically, a mechanism to solve the administrative problems in enabling end users to automatically establish service agreements for any available service, from any available provider.
The aims of this work are to:
1. enable the description of service level agreements(SLA) for generalised telecommunication-based services, and
2. provide mechanisms by which those service level agreements may be managed.
The term âgeneralised servicesâ means that all service types are managed using a common framework and set of processes.
To derive at a suitable service level agreement description language, the characteristics of telecommunication-based services are first analysed, along with considerations in delivering a service, including service quality, resource allocation and configuration, service pricing and service ubiquity. The current art in SLA description is studied and the requirements of an appropriate language are proposed. An ontological approach to SLA description is adopted, and an SLA description language is developed based on semantic web technologies.
To develop the mechanisms for SLA management, the current art is first analysed, and a set of requirements for a suitable SLA management framework are proposed. These requirements are used to guide the design of a multi-agent SLA negotiation framework, including a detailed description of the communication model, framework processes, and social behaviour of the agents involved.
Finally, the SLA description language and the negotiation framework are compared with the closest art, and are assessed against tightly argued criteria. An experimental framework and use cases are developed to explore an application of the proposed solution, and to validate completeness.
The approach taken has led to the following two key contributions:
1. A set of formal ontologies that may be used to semantically describe secure service level agreements for any application domain.
2. A multi-agent system providing an open market where services can be discovered, participants identified, and negotiation performed using context specific mechanisms.
The conclusions of the work are that an ontology-based SLA description language is appropriate for describing generalised SLAs, and that a distributed, agent based negotiation platform that is based on an open market and uses a minimal set of core processes with an extensible, ontology based communication mechanism is appropriate for managing service level agreements in a generalised, automated and ubiquitous way
Deletions of the derivative chromosome 9 occur at the time of the Philadelphia translocation and provide a powerful and independent prognostic indicator in chronic myeloid leukemia
Chronic myeloid leukemia (CML) is characterized by formation of the BCR-ABL fusion gene, usually as a consequence of the Philadelphia (Ph) translocation between chromosomes 9 and 22. Large deletions on the derivative chromosome 9 have recently been reported, but it was unclear whether deletions arose during disease progression or at the time of the Ph translocation. Fluorescence in situ hybridization (FISH) analysis was used to assess the deletion status of 253 patients with CML. The strength of deletion status as a prognostic indicator was then compared to the Sokal and Hasford scoring systems. The frequency of deletions was similar at diagnosis and after disease progression but was significantly increased in patients with variant Ph translocations. In patients with a deletion, all Ph+ metaphases carried the deletion. The median survival of patients with and without deletions was 38 months and 88 months, respectively (P = .0001). By contrast the survival difference between Sokal or Hasford high-risk and non-high-risk patients was of only borderline significance (P = .057 and P = .034). The results indicate that deletions occur at the time of the Ph translocation. An apparently simple reciprocal translocation may therefore result in considerable genetic heterogeneity ab initio, a concept that is likely to apply to other malignancies associated with translocations. Deletion status is also a powerful and independent prognostic factor for patients with CML. The prognostic significance of deletion status should now be studied prospectively and, if confirmed, should be incorporated into management decisions and the analysis of clinical trials. (C) 2001 by The American Society of Hematology
Exploring what lies behind public preferences for avoiding health losses caused by lapses in healthcare safety and patient lifestyle choices
© 2013 Singh et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.Background: Although many studies have identified public preferences for prioritising health care interventions based on characteristics of recipient or care, very few of them have examined the reasons for the stated preferences. We conducted an on-line person trade-off (PTO) study (N=1030) to investigate whether the public attach a premium to the avoidance of ill health associated with alternative types of responsibilities: lapses in healthcare safety, those caused by individual action or lifestyle choice; or genetic conditions. We found that the public gave higher priority to prevention of harm in a hospital setting such as preventing hospital associated infections than genetic disorder but drug administration errors were valued similar to genetic disorders. Prevention of staff injuries, lifestyle diseases and sports injuries, were given lower priority. In this paper we aim to understand the reasoning behind the responses by analysing comments provided by respondents to the PTO questions. Method: A majority of the respondents who participated in the survey provided brief comments explaining preferences in free text responses following PTO questions. This qualitative data was transformed into explicit codes conveying similar meanings. An overall coding framework was developed and a reliability test was carried out. Recurrent patterns were identified in each preference group. Comments which challenged the assumptions of hypothetical scenarios were also investigated. Results: NHS causation of illness and a duty of care were the most cited reasons to prioritise lapses in healthcare safety. Personal responsibility dominated responses for lifestyle related contexts, and many respondents mentioned that health loss was the result of the individualâs choice to engage in risky behaviour. A small proportion of responses questioned the assumptions underlying the PTO questions. However excluding these from the main analysis did not affect the conclusions.
Conclusion: Although some responses indicated misunderstanding or rejection of assumptions we put forward, the results were still robust. The reasons put forward for responses differed between comparisons but responsibility was the most frequently cited. Most preference elicitation studies only focus on eliciting numerical valuations but allowing for qualitative data can augment understanding of preferences as well as verifying results.EPSRC through the MATCH programme(EP/F063822/1 and EP/G012393/1) and HERG within Brunel University
Acoustic Emission in a Fiber Composite Plate
Acoustic emission techniques are being widely used for the detection of faults in engineering structures. These techniques allow the possibility of real time monitoring of large areas of in-service structures, with a high probability of crack detection (see e.g. Granata et. al. [1], Jacobs et. al. [2]). A prerequisite for this application is a thorough understanding of the nature of the stress waves generated as a result of internal impulsive events. A number of authors have examined the problem both theoretically and experimentally and the reader is referred to [2] for a list of references. Amongst these in particular, Ceranoglu and Pao [3] have made a comprehensive theoretical and numerical study of the transient response of an isotropic plate to a variety of dynamic nuclei of strain They show plots of the time histories of both the normal and tangential surface displacements at the epicenter and at radial distances of two, four and six plate thicknesses from the source location. Results are presented for surface sources and buried sources located at the mid-plane of the plate. The surface sources consist of normal, tangential and oblique step function point loads, whilst the buried forces include also double forces, couples, centers of explosion, centers of rotation and double couples without moment.</p
6D Effective Action of Heterotic Compactification on K3 with nontrivial Gauge Bundles
We compute the six-dimensional effective action of the heterotic string
compactified on K3 for the standard embedding and for a class of backgrounds
with line bundles and appropriate Yang-Mills fluxes. We compute the couplings
of the charged scalars and the bundle moduli as functions of the geometrical K3
moduli from a Kaluza-Klein analysis. We derive the D-term potential and show
that in the flux backgrounds U(1) vector multiplets become massive by a
Stuckelberg mechanism.Comment: 41 pages, typos corrected, references adde
Timing of retinal neuronal and axonal loss in MS: a longitudinal OCT study
The objective of the study was to investigate the timing of central nervous system tissue atrophy in MS by evaluating longitudinal retinal volume changes in a broadly representative cohort with disease duration across the entire arc of disease. In this longitudinal study, 135 patients with MS and 16 healthy reference subjects underwent spectral-domain optical coherence tomography (OCT) at baseline and 2 years later. Following OCT quality control, automated segmentation of the peripapillary retinal nerve fiber layer (pRNFL), macular ganglion cellâinner plexiform layer (mGCIPL) and macular inner nuclear layer (mINL) was performed. Generalized estimation equations were used to analyze longitudinal changes and associations with disease duration and clinical measures. Participants had a median disease duration at baseline of 16.4 years (range 0.1â45.4). Nearly half (44 %) of the MS patients had previously experienced MS-related optic neuritis (MSON) more than 6 months prior. The MS patients demonstrated a significant decrease over 2 years of the pRNFL (â1.1 ”m, 95 % CI 1.4â0.7, p < 0.001) and mGCIPL (â1.1 ”m, 95 % CI â1.4 to â0.8, p < 0.001). This thinning was most pronounced early in the course of disease. These findings were irrespective of previous episodes of MSON. No consistent pattern of change was observed for the mINL (â0.03 ”m, 95 % CI â0.2 to 0.2, p = 0.795). This longitudinal study demonstrated that injury of the innermost retinal layers is found in MS and that this damage occurs most rapidly during the early stages of disease. The attenuation of atrophy with longer disease duration is suggestive of a plateau effect. These findings emphasize the importance of early intervention to prevent such injury
Estimation of Dietary Iron Bioavailability from Food Iron Intake and Iron Status
Currently there are no satisfactory methods for estimating dietary iron absorption (bioavailability) at a population level, but this is essential for deriving dietary reference values using the factorial approach. The aim of this work was to develop a novel approach for estimating dietary iron absorption using a population sample from a sub-section of the UK National Diet and Nutrition Survey (NDNS). Data were analyzed in 873 subjects from the 2000â2001 adult cohort of the NDNS, for whom both dietary intake data and hematological measures (hemoglobin and serum ferritin (SF) concentrations) were available. There were 495 men aged 19â64 y (mean age 42.7±12.1 y) and 378 pre-menopausal women (mean age 35.7±8.2 y). Individual dietary iron requirements were estimated using the Institute of Medicine calculations. A full probability approach was then applied to estimate the prevalence of dietary intakes that were insufficient to meet the needs of the men and women separately, based on their estimated daily iron intake and a series of absorption values ranging from 1â40%. The prevalence of SF concentrations below selected cut-off values (indicating that absorption was not high enough to maintain iron stores) was derived from individual SF concentrations. An estimate of dietary iron absorption required to maintain specified SF values was then calculated by matching the observed prevalence of insufficiency with the prevalence predicted for the series of absorption estimates. Mean daily dietary iron intakes were 13.5 mg for men and 9.8 mg for women. Mean calculated dietary absorption was 8% in men (50th percentile for SF 85 ”g/L) and 17% in women (50th percentile for SF 38 ”g/L). At a ferritin level of 45 ”g/L estimated absorption was similar in men (14%) and women (13%). This new method can be used to calculate dietary iron absorption at a population level using data describing total iron intake and SF concentration
Bayesian Conditioning, the Reflection Principle, and Quantum Decoherence
The probabilities a Bayesian agent assigns to a set of events typically
change with time, for instance when the agent updates them in the light of new
data. In this paper we address the question of how an agent's probabilities at
different times are constrained by Dutch-book coherence. We review and attempt
to clarify the argument that, although an agent is not forced by coherence to
use the usual Bayesian conditioning rule to update his probabilities, coherence
does require the agent's probabilities to satisfy van Fraassen's [1984]
reflection principle (which entails a related constraint pointed out by
Goldstein [1983]). We then exhibit the specialized assumption needed to recover
Bayesian conditioning from an analogous reflection-style consideration.
Bringing the argument to the context of quantum measurement theory, we show
that "quantum decoherence" can be understood in purely personalist
terms---quantum decoherence (as supposed in a von Neumann chain) is not a
physical process at all, but an application of the reflection principle. From
this point of view, the decoherence theory of Zeh, Zurek, and others as a story
of quantum measurement has the plot turned exactly backward.Comment: 14 pages, written in memory of Itamar Pitowsk
The Structure of n-Point One-Loop Open Superstring Amplitudes
In this article we present the worldsheet integrand for one-loop amplitudes
in maximally supersymmetric superstring theory involving any number n of
massless open string states. The polarization dependence is organized into the
same BRST invariant kinematic combinations which also govern the leading string
correction to tree level amplitudes. The dimensions of the bases for both the
kinematics and the associated worldsheet integrals is found to be the unsigned
Stirling number S_3^{n-1} of first kind. We explain why the same combinatorial
structures govern on the one hand finite one-loop amplitudes of equal helicity
states in pure Yang Mills theory and on the other hand the color tensors at
quadratic alpha prime order of the color dressed tree amplitude.Comment: 75 pp, 8 figs, harvmac TeX, v2: published versio
A phenomenological description of quantum-gravity-induced space-time noise
I propose a phenomenological description of space-time foam and discuss the
experimental limits that are within reach of forthcoming experiments.Comment: 10 pages, LaTex, 1 figure. Short paper, omitting most technical
details. More detailed analysis was reported in gr-qc/010400
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