487 research outputs found

    A MapReduce Framework for Analysing Portfolios of Catastrophic Risk with Secondary Uncertainty

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    AbstractThe design and implementation of an extensible framework for performing exploratory analysis of complex property portfolios of catastrophe insurance treaties on the Map-Reduce model is presented in this paper. The framework implements Aggregate Risk Analysis, a Monte Carlo simulation technique, which is at the heart of the analytical pipeline of the modern quantitative insurance/reinsurance pipeline. A key feature of the framework is the support for layering advanced types of analysis, such as portfolio or program level aggregate risk analysis with secondary uncertainty (i.e. computing Probable Maximum Loss (PML) based on a distribution rather than mean values). Such in-depth analysis is not supported by production-based risk management systems since they are constrained by hard response time requirements placed on them. On the other hand, this paper reports preliminary experimental results to demonstrate that in-depth aggregate risk analysis can be realized using a framework based on the MapReduce model

    The Short-term Car Flow Planning Model in Rail Freight Company – Case Study

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    AbstractWith the promotion of the environmentally friendly transportation modes (the European Commission supports the freight transport operations in the rail sector), an increase in the diversification of the demand is observed. While most rail freight companies tend to apply fixed schedules, this approach is not effective turns out to be ineffective due to the need to meet the customer's specific requirements.The purpose of this paper is to present a case study of empty wagon flow planning over a medium term horizon and to discuss the opportunities of improvement of this plans by discrete optimization. In order to increase the utilization and availability of wagons, the planning procedure with a rolling horizon has to be implemented. Unfortunately, since the plan has to be updated ca. every 4hours, this planning approach needs effective optimization tools. Our hybrid two-stage approach is designed to be implemented in such business environment. This formulation allows us to solve real life instances even for a 7-day time horizon

    Mushrooms Red Book of Ukraine in Culture. 1. Patterns of Growth Hericium coralloides

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    На території НПП «Гуцульщина» виявлено лише три локалітети Hericium coralloides – гриба, занесеного до Червоної книги України. У результаті проведених досліджень виділено в чисту культуру аборигенний штам К01. Як для виділення, так і для підтримки та забезпечення життєздатності гриба в культурі картопельно-глюкозний агар виявився оптимальним серед апробованих середовищ. Індивідуальні особливості росту H. coralloides К01 вказують на вузькі трофічні можливості цього штаму при поверхневому культивуванні, оскільки з п’яти апробованих середовищ придатними для росту виявилися лише два. Цей штам гриба вважаємо перспективним для використання як інокулянта відповідних субстратів у природному середовищі, оскільки для нього характерні високі показники радіального росту, короткий період log-фази та утворення в чистій культурі стадії телеоморфи. The national park «Hutsulshchyna» found only three localities of Hericium coralloides − mushroom Red Book of Ukraine. The result of the research was to obtain in a pure culture of the native strain K01. As for the release, and to support and ensure the viability of the fungus in culture potato - glucose agar was the best among the tested environments. Individual features of the growth of H. coralloides K01 indicate the narrow trophic features of this strain at cultivation because from five tested media suitable for growth were only two. This strain K01 H. coralloides may be considered promising for use as an inoculant respective substrates in the environment , because it is characterized by high rates of radial growth , a short period of log- phase and ability to form stage teleomorfy in pure culture.Роботу виконано у НПП «Гуцульщина», ННЦ «Інститут біології» КНУ ім. Т. Шевченк

    Application of Simple Smart Logic for Waterflooding Reservoir Management

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    A simple smart logic for controlling inflow control valves (ICV) in waterflooding reservoir management is implemented and analyzed, with the final objective of improving the long term financial return of a petroleum reservoir. Such a control is based in a reactive simple logic that responds to the watercut measured in the ICV. Basically, when the watercut increases, the ICV is set to close proportionally. For comparison purposes, four strategies are presented: base case scenario with conventional control, the best completion configuration found by trial-and-error, the reactive control, and a deterministic optimal control based on Nonlinear Gradient Method with adjoint-gradient formulation is shown for comparison purposes. Finally, all four strategies are tested again in different reservoir realizations in order to mimic the geological uncertainties. Two different synthetic reservoir models were studied. First, a simple cube with a five-spot well configuration, in which the permeability field has a horizontal pattern defined by lognormal distributions. The second model is a benchmark proposed by the Dutch university, TU delft, with 101 channelized permeability fields representing river patterns. For the first model, no significant relative gain is found neither in the variable control nor in the optimal control. Manly because of the high homogeneity of the reservoir models. Therefore, no intelligent completion is recommended. On the other hand, for the second and more complex case, the results indicate an expressive relative gain in the use of simple reactive logic. Besides, this type of control achieves results nearly as good as the optimal control. The test in different realizations, however, shows that reservoir characterization is still a key part of any attempt to improve production. Although the variable reactive control is semi-independent, with action being taken based on measurements, some parameters need a priori model to be tuned

    Treatment of Elderly Patients with Squamous Cell Carcinoma of the Head and Neck

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    The demographics of squamous cell carcinoma of the head and neck (SCCHN) is marked by a growing number of patients aged 65 and over, which is in line with global projections for other cancer types. In developed countries, more than half of new SCCHN cases are diagnosed in older people and in 15 years from now, the proportion is expected to rise by more than 10%. Still, a high-level evidence-based consensus to guide the clinical decision process is strikingly lacking. The available data from retrospective studies and subset analyses of prospective trials suffer from a considerable underrepresentation of senior participants. The situation is even more challenging in the recurrent and/or metastatic setting, where usually only palliative measures are employed. Nevertheless, it is becoming clear that if treated irrespective of chronological age, fit elderly patients in a good general condition and with a low burden of comorbidities may derive a similar survival advantage as their younger counterparts. Despite that, under-treatment represents a widespread phenomenon and together with competing non-cancer mortality is suggested to be an important cause of the worse treatment outcomes observed in this population. Due to physiological changes in drug metabolism occurring with advancing age, the major concerns relate to chemotherapy administration. In locally advanced SCCHN, concurrent chemoradiotherapy in patients over 70 years remains a point of controversy owing to its possibly higher toxicity and questionable benefit. However, accumulating evidence suggests that it should, indeed, be considered in selected cases when biological age is taken into account. Results from a randomised trial conducted in lung cancer showed that treatment selection based on a comprehensive geriatric assessment (CGA) significantly reduced toxicity. However, a CGA is time-consuming and not necessary for all patients. To overcome this hurdle, geriatric screening tools have been introduced to decide who needs such a full evaluation. Among the various screening instruments, G8 and Flemish version of the Triage Risk Screening Tool were prospectively verified and found to have prognostic value. We therefore conclude that also in SCCHN, the application of elderly-specific prospective trials and integration of clinical practice-oriented assessment tools and predictive models should be promoted
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