ICONA: Inter Cluster ONOS Network Application

Several Network Operating Systems (NOS) have been proposed in the last few years for Software Defined Networks; however, a few of them are currently offering the resiliency, scalability and high availability required for production environments. Open Networking Operating System (ONOS) is an open source NOS, designed to be reliable and to scale up to thousands of managed devices. It supports multiple concurrent instances (a cluster of controllers) with distributed data stores. A tight requirement of ONOS is that all instances must be close enough to have negligible communication delays, which means they are typically installed within a single datacenter or a LAN network. However in certain wide area network scenarios, this constraint may limit the speed of responsiveness of the controller toward network events like failures or congested links, an important requirement from the point of view of a Service Provider. This paper presents ICONA, a tool developed on top of ONOS and designed in order to extend ONOS capability in network scenarios where there are stringent requirements in term of control plane responsiveness. In particular the paper describes the architecture behind ICONA and provides some initial evaluation obtained on a preliminary version of the tool.Comment: Paper submitted to a conferenc

An experimental investigation of the effect of defect shape and orientation on the burst pressure of pressurised pipes

The burst pressure of commonly used ductile steel pipes in oil and gas industries, i.e. X52 and X60, is measured under internal pressure loading. The pipes were machined with circular and boxed defects at different orientations to simulate actual metal loss defects. Defect shapes and orientations were investigated in detail to study how they affect the failure behaviour of interacting defects. The experimental burst pressure results were compared with those obtained using existing analytical methods from Design Codes. Comparison of the results showed conservatism in the existing analytical methods which may potentially lead to unnecessary plant shutdowns and pipe repairs. The outcome of the experimental tests revealed that the shapes of the defects have very small influence on the defect interaction behaviour. The burst tests interestingly showed that the defect orientation has an important effect on defect interaction. Defects oriented in the hoop and diagonal directions showed no defect interaction even when spaced by a distance of one wall thickness, while defects oriented in the longitudinal directions showed that defects interact even when the spacing is up to six wall thickness but the interaction fades away for defects spaced at longer distances

Treating symptomatic uterine fibroids with myomectomy: current practice and views of UK consultants

Background: The demand for uterus-sparing treatments is increasing as more women postpone childbirth to their 30–40s, when fibroids are more symptomatic. With an increasing choice of treatment options and changing care-provider profiles, now is an opportune time to survey current practices and opinions. Using a 25-stem questionnaire, a web-based survey was used to capture the practices and opinions of UK consultant gynecologists on the treatment of symptomatic fibroids, including the types of procedure most frequently used, methods used to reduce blood loss, and awareness and acceptability of treatment options, and to assess the impact of gender and experience of the treating gynecologist. Results: The response rate was 22%. Laparascopic myomectomy is used least frequently, with 80% of the respondents using GnRHa preoperatively to minimize blood loss and correct anemia, while vasopressin is most frequently used to reduce intraoperative blood loss. Female consultants operate significantly less frequently than males. Those with more than 10 years consultant experience are more likely to perform an open myomectomy compared to those with less than 10 years experience. Conclusions: Compared to a similar survey performed 10 years ago, surgical methods remain to be the most common treatments, but use of less invasive treatments such as UAE has increased. Consultants’ attitudes appear to be responding to the patient demand for less radical treatments. However, it is yet to be seen if the changing consultant demographics will keep up with this demand. The low response rate warrants cautious interpretation of the results, but they provide an interesting snapshot of current views and practices

The ATLAS Trigger/DAQ Authorlist, version 3.0

This is the ATLAS Trigger/DAQ Authorlist, version 3.0, 11 September 200

The ATLAS Trigger/DAQ Authorlist, version 2.0

This is the ATLAS Trigger/DAQ Authorlist, version 2.0, 31 July 200

The ATLAS Trigger/DAQ Authorlist, version 1.0

This is a reference document giving the ATLAS Trigger/DAQ author list, version 1.0 of 20 Nov 2008

The ATLAS Trigger/DAQ Authorlist, version 3.1

This is the ATLAS Trigger/DAQ Authorlist, version 3.1, 17 September 200

Analiza termosprężysta sprzęgła wielotarczowego za pomocą metody elementu skończonego

The high thermal stresses generated between the contacting surfaces of a multidisc clutch system (pressure plate, clutch discs, plate separators, and piston) due to the frictional heating generated during slipping are considered to be one of the main reasons for clutch failure related to contact surfaces. A finite element technique has been used to study the transient thermoelastic phenomena of a multi-disc dry clutch. The results present the contact pressure distribution, the temperature evaluation, and the heat flux generated along the frictional surfaces. Analysis has been completed using two-dimensional axisymmetric model to simulate the multi-disc clutch. ANSYS software has been used to perform the numerical calculation in this paper.Wysokie naprężenia cieplne generowane między stykającymi się powierzchniami systemu sprzęgła wielotarczowego (tarcza dociskowa stała, tarcze sprzęgłowe, tarcze rozdzielające, tarcza dociskowa ruchoma) w wyniku tarcia ślizgowego są uważane za jedną z głównych przyczyn uszkodzeń powierzchni stykowych sprzęgła. Do badania nieustalonych przebiegów termosprężystych w suchym sprzęgle wielotarczowym zastosowano metodę elementu skończonego (MES). Wyniki przedstawiają rozkład nacisków stykowych, ocenę temperatury i strumienia ciepła generowanego na powierzchniach ciernych. Analizę przeprowadzono z zastosowaniem dwuwymiarowego modelu osiowosymetrycznego symulującego sprzęgło wielotarczowe. Użyto oprogramowania ANSYS do przeprowadzenia obliczeń numerycznych w niniejszej pracy