Extremes on the discounted aggregate claims in a time dependent risk model

This paper presents an extension of the classical compound Poisson risk model for which the inter-claim time and the forthcoming claim amount are no longer independent random variables (rv's). Asymptotic tail probabilities for the discounted aggregate claims are presented when the force of interest is constant and the claim amounts are heavy tail distributed rv's. Furthermore, we derive asymptotic finite time ruin probabilities, as well as asymptotic approximations for some common risk measures associated with the discounted aggregate claims. A simulation study is performed in order to validate the results obtained in the free interest risk model

Journal bearing status identification with acoustic emission measurements and data clustering

The laboratory scale journal bearing lubrication regimes were analysed with wide band acoustic emission (AE) measurements. Data analysis was supported by data-based clustering of AE data. The approach can be effectively used to reveal fundamental lubrication modes, i.e., hydrodynamic (HL), mixed (ML) and boundary (BL) lubrication as a function of Hersey number. Besides AE the other parameters monitored were friction torque, bearing temperature, loading, sliding velocity and oil pressure. The materials used in the experiments were case-hardened 18CrNiMo7-6 steel and nitrided 42CrMo7 steel. The tests were lubricated with synthetic extreme-pressure gear oil (SGN 320) and the bearing temperature was kept constant during the tests. The bearing pressure and sliding velocity during tests were varied in the wide range resulting in different lubrication situations. The acoustic emission signals power and frequency content was analysed, and essential features were extracted for data clustering. For lubrication regime change identification the parameters such as signal RMS and coefficient of variation (CV) proved to be important, while signal kurtosis showed to be the most sensitive in discovering anomalies. The sensitivity requires data filtering to remove erroneous peaks. It is also interesting to notice the changes in AE frequency due to different lubrication situation.  In literature different clustering and classification methods has been proposed and applied for journal bearing status identification. Here the selected unsupervised clustering method was the mean-shift clustering due to fact, that the lubrication regimes in the Stribeck curve form an inseparable continuum. The algorithm does not require specifying the number of clusters in advance, i.e., the clusters are determined by the algorithm with respect to the data

Cosmological Backreaction from Perturbations

We reformulate the averaged Einstein equations in a form suitable for use with Newtonian gauge linear perturbation theory and track the size of the modifications to standard Robertson-Walker evolution on the largest scales as a function of redshift for both Einstein de-Sitter and Lambda CDM cosmologies. In both cases the effective energy density arising from linear perturbations is of the order of 10^-5 the matter density, as would be expected, with an effective equation of state w ~ -1/19. Employing a modified Halofit code to extend our results to quasilinear scales, we find that, while larger, the deviations from Robertson-Walker behaviour remain of the order of 10^-5.Comment: 15 pages, 8 figures; replaced by version accepted by JCA

Evaluation of myosin VI, E-cadherin and beta-catenin immunostaining in renal cell carcinoma

<p>Abstract</p> <p>Background</p> <p>Renal cell carcinoma (RCC) is a cancer of increasing incidence and mortality. Currently, there are no immunohistochemical prognostic markers for RCCs in routine use. The aim of this study was to examine for the first time the immunostaining of myosin VI in RCCs as well as its association with E-cadherin and beta-catenin immunostaining and the prognostic significance of these markers in RCCs.</p> <p>Methods</p> <p>Our study population consisted of 152 patients who underwent surgery for RCCs between 1990 and 1999. The tumours were examined with three immunohistochemical markers: myosin VI, E-cadherin and beta-catenin.</p> <p>Results</p> <p>The immunostaining for cytoplasmic myosin VI was common (72%). One-third of the tumours were immunopositive for nuclear myosin VI. Cytoplasmic myosin VI immunopositivity and nuclear beta-catenin immunostaining were associated with lower Fuhrman grades (<it>p </it>= 0.04 and <it>p </it>= 0.005, respectively), but not stages. There was no significant association between myosin VI immunostaining and the histological subtype of RCC. Nuclear myosin VI was associated with the nuclear expression of beta-catenin. A direct association could also be proven between membranous E-cadherin and cytoplasmic beta-catenin. Cytoplasmic myosin VI immunostaining was a marker of poorer prognosis in multivariate Cox regression model adjusted with stage and Fuhrman grade with hazard ratio 2.4 (95% confidence interval 1.1 to 5.0 with <it>p </it>= 0.024).</p> <p>Conclusions</p> <p>Cytoplasmic myosin VI immunopositivity and nuclear beta-catenin immunostaining were associated with lower Fuhrman grades, and there was a strong positive relationship between E-cadherin immunostaining and beta-catenin immunostaining in RCCs. Cytoplasmic myosin VI immunostaining was associated with poorer prognosis in RCCs.</p

Tribological performance of an H-DLC coating prepared by PECVD

Carbon-based coatings are of wide interest due to their application in machine elements subjected to continuous contact where fluid lubricant films are not permitted. This paper describes the tribological performance under dry conditions of duplex layered H-DLC coating sequentially deposited by microwave excited plasma enhanced chemical vapour deposition on AISI 52100 steel. The architecture of the coating comprised Cr, WC, and DLC (a-C:H) with a total thickness of 2.8 μm and compressive residual stress very close to 1 GPa. Surface hardness was approximately 22 GPa and its reduced elastic modulus around 180 GPa. Scratch tests indicated a well adhered coating achieving a critical load of 80 N. The effect of normal load on the friction and wear behaviours were investigated with steel pins sliding against the actual coating under dry conditions at room temperature (20 ± 2°C) and 35-50% RH. The results show that coefficient of friction of the coating decreased from 0.21 to 0.13 values with the increase in the applied loads (10-50 N). Specific wear rates of the surface coating also decrease with the increase in the same range of applied loads. Maximum and minimum values were 14 × 10-8 and 5.5 × 10-8 mm-3/N m, respectively. Through Raman spectroscopy and electron microscopy it was confirmed the carbon-carbon contact, due to the tribolayer formation on the wear scars of the coating and pin. In order to further corroborate the experimental observations regarding the graphitisation behaviour, the existing mathematical relationships to determine the graphitisation temperature of the coating/steel contact as well as the flash temperature were used

The EPL drama – paving the way for more illegal streaming? Digital piracy of live sports broadcasts in Singapore

Along with the rise of digital media technologies, digitisation disrupted and reconfigured the established practices of previously discrete media markets. The erosion of conventional media divisions has resulted in wide-ranging ramifications for sports broadcasts as it shifts from the historically dominant platform of broadcast television to the digital environment of the Internet in the new mediascape. This paper considers how these emergent practices from the advent of media technology have represented significant challenges to the mediascape of sports broadcasts in Singapore. Given the popularity of mediated Western sports in Singapore, it comes as no surprise that the challenge of sports broadcasts piracy is acute in the country. Singapore has an exceedingly high degree of online infringement compared to other countries in the region. Data discloses that Singapore’s per capita infringement ranks first in Asia and fifth highest globally. This paper seeks to review the phenomenon in Singapore, examining the drivers that created the unique market dynamics which shaped the piracy of sports broadcasts in the country. The paper goes on to discuss provisions in Singapore in terms of copyright law and enforcement that are in place for the deterrence of sports broadcasts piracy. It considers the adequacy of these current approaches and concludes with an observation of how Singapore will seek to adjust to the continual digital advancement in its battle against digital sports piracy. The outcome of this assessment helps provide an additional account for its comparison with existing discourse on the challenges of digitisation on sports broadcasts development in advanced capitalist Asian countries. Publisher statement: This is an Accepted Manuscript of an article published by Taylor &amp; Francis in Leisure Studies on 27 April 2015, available online: http://www.tandfonline.com/doi/abs/10.1080/02614367.2015.103531

Inventory of long and short term future needs of food chain users for future functions of internet

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The effect of coating properties on the performance of a-C:H and ta-C films

DLC films cover a wide range of different carbon based coatings, starting from soft to extremely hard diamond-like carbon films. In this study two different types of DLC films have been studied in respect of their stress and strain characteristics and tribological performance. The coatings are hydrogenated amorphous carbon (a-C:H) coatings deposited by PECVD and tetrahedral amorphous carbon (ta-C) coating deposited by filtered arc technique. In order to evaluate the mechanical behaviour of the coatings under load, 3D FE modelling was carried out in combination with scratch testing. Also the tribological performance was evaluated with pin-on-disc tests using stepwise increasing normal load. The 3D FEM model was developed for calculating the stress and strain distributions of DLC coated systems and to evaluate how coating thickness and elastic properties affect the stress-strain state at crack initiation location. The simulation was compared to the findings to experimental observations in scratch test contact conditions, when the spherical diamond tip was moving with increased load on a coated surface. The coating performance was evaluated with scratch testing to detect the crack generation as well as the coating adhesion. When combining the simulated coating characteristics with empirical observation of coating fracture patterns the coating fracture performance and tolerance to cracking could be evaluated. A major effect of the coating elastic modulus on the stress and fracture behaviour of the coatings was observed. In the tribological testing the both coatings had a low friction performance. In the tribological testing with stepwise increasing load, the critical load for coating delamination was higher for the a-C:H coating, which is in accordance with the results of FE modelling of coating stress state

The unruptured intracranial aneurysm treatment score A multidisciplinary consensus

Objective: We endeavored to develop an unruptured intracranial aneurysm (UIA) treatment score (UIATS) model that includes and quantifies key factors involved in clinical decision-making in the management of UIAs and to assess agreement for this model among specialists in UIA management and research. Methods: An international multidisciplinary (neurosurgery, neuroradiology, neurology, clinical epidemiology) group of 69 specialists was convened to develop and validate the UIATS model using a Delphi consensus. For internal (39 panel members involved in identification of relevant features) and external validation (30 independent external reviewers), 30 selected UIA cases were used to analyze agreement with UIATS management recommendations based on a 5-point Likert scale (5 indicating strong agreement). Interrater agreement (IRA) was assessed with standardized coefficients of dispersion (v(r)*) (v(r)* 5 0 indicating excellent agreement and v(r)* = 1 indicating poor agreement). Results: The UIATS accounts for 29 key factors in UIA management. Agreement with UIATS (mean Likert scores) was 4.2 (95% confidence interval [CI] 4.1-4.3) per reviewer for both reviewer cohorts; agreement per case was 4.3 (95% CI 4.1-4.4) for panel members and 4.5 (95% CI 4.3-4.6) for external reviewers (p = 0.017). Mean Likert scores were 4.2 (95% CI 4.1-4.3) for interventional reviewers (n = 56) and 4.1 (95% CI 3.9-4.4) for noninterventional reviewers (n = 12) (p = 0.290). Overall IRA (v(r)*) for both cohorts was 0.026 (95% CI 0.019-0.033). Conclusions: This novel UIA decision guidance study captures an excellent consensus among highly informed individuals on UIA management, irrespective of their underlying specialty. Clinicians can use the UIATS as a comprehensive mechanism for indicating how a large group of specialists might manage an individual patient with a UIA.Peer reviewe

Multichannel optical sensor for oil film pressure measurement in engine main bearing

An optical sensor has been developed for experimental determination of oil film pressure in journal bearings. The non-intrusive fibre optic sensor is integrated in the sliding surface of the bearing to measure the actual oil film pressure under load without disturbing the actual tribological contact conditions. The sensors with a multichannel system also allowed the use of several optical sensors simultaneously. Four optical sensors were integrated in a hydrodynamic journal bearing of a large scale diesel engine and the engine tests were carried out with different loads to study the sensor operation in demanding operating conditions. The oil film pressure was successfully measured and the results showed differences in bearing pressure depending on the position of the sensor and on the operating cycle of the cylinders. The optical sensor was capable to measure the oil film pressure in journal bearing with a good sensitivity and repeatability during the tests. &nbsp