Berne University of Applied science

Bern, Switzerland

Berne University of Applied science

Bern, Switzerland
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Albaba A.,IRSTEA | Albaba A.,Berne University of Applied science | Lambert S.,IRSTEA | Faug T.,IRSTEA
EPJ Web of Conferences | Year: 2017

The present paper tackles the problem of the impact of a dry granular avalanche-flow on a rigid wall of semi-infinite height. An analytic force model based on depth-averaged shock theory is proposed to describe the flow-wall interaction and the resulting impact force on the wall. Provided that the analytic force model is fed with the incoming flow conditions regarding thickness, velocity and density, all averaged over a certain distance downstream of the undisturbed incoming flow, it reproduces very well the time history of the impact force actually measured by detailed discrete element simulations, for a wide range of slope angles. © The Authors, published by EDP Sciences, 2017.


Steiner P.,University of Bern | Steiner P.,Berne University of Applied science | Ebneter A.,Inselspital | Berger L.E.,Inselspital | And 9 more authors.
Investigative Ophthalmology and Visual Science | Year: 2015

PURPOSE. Selective retina therapy (SRT) is a novel treatment for retinal pathologies, solely targeting the RPE. During SRT, the detection of an immediate tissue reaction is challenging, as tissue effects remain limited to intracellular RPE photodisruption. Time-resolved ultra-high axial resolution optical coherence tomography (OCT) is thus evaluated for the monitoring of dynamic optical changes at and around the RPE during SRT. METHODS. An experimental OCT system with an ultra-high axial resolution of 1.78 μm was combined with an SRT system and time-resolved OCT M-scans of the target area were recorded from four patients undergoing SRT. Optical coherence tomography scans were analyzed and OCT morphology was correlated with findings in fluorescein angiography, fundus photography, and cross-sectional OCT. RESULTS. In cases in which the irradiation caused RPE damage proven by fluorescein angiography, the lesions were well discernible in time-resolved OCT images but remained invisible in fundus photography and cross-sectional OCT acquired after treatment. If RPE damage was introduced, all applied SRT pulses led to detectable signal changes in the timeresolved OCT images. The extent of optical signal variation seen in the OCT data appeared to scale with the applied SRT pulse energy. CONCLUSIONS. The first clinical results proved that successful SRT irradiation induces detectable changes in the OCT M-scan signal while it remains invisible in conventional ophthalmoscopic imaging. Thus, real-time high-resolution OCT is a promising modality to monitor and analyze tissue effects introduced by selective retina therapy and may be used to guide SRT in an automatic feedback mode (www.swissmedic.ch number, 2011-MD-0006). © 2015 The Association for Research in Vision and Ophthalmology, Inc.


PubMed | University of Lübeck, Inselspital, Medizinische Hochschule Hanover, University of Bern and Berne University of Applied science
Type: Clinical Trial | Journal: Investigative ophthalmology & visual science | Year: 2015

Selective retina therapy (SRT) is a novel treatment for retinal pathologies, solely targeting the RPE. During SRT, the detection of an immediate tissue reaction is challenging, as tissue effects remain limited to intracellular RPE photodisruption. Time-resolved ultra-high axial resolution optical coherence tomography (OCT) is thus evaluated for the monitoring of dynamic optical changes at and around the RPE during SRT.An experimental OCT system with an ultra-high axial resolution of 1.78 m was combined with an SRT system and time-resolved OCT M-scans of the target area were recorded from four patients undergoing SRT. Optical coherence tomography scans were analyzed and OCT morphology was correlated with findings in fluorescein angiography, fundus photography, and cross-sectional OCT.In cases in which the irradiation caused RPE damage proven by fluorescein angiography, the lesions were well discernible in time-resolved OCT images but remained invisible in fundus photography and cross-sectional OCT acquired after treatment. If RPE damage was introduced, all applied SRT pulses led to detectable signal changes in the time-resolved OCT images. The extent of optical signal variation seen in the OCT data appeared to scale with the applied SRT pulse energy.The first clinical results proved that successful SRT irradiation induces detectable changes in the OCT M-scan signal while it remains invisible in conventional ophthalmoscopic imaging. Thus, real-time high-resolution OCT is a promising modality to monitor and analyze tissue effects introduced by selective retina therapy and may be used to guide SRT in an automatic feedback mode (www.swissmedic.ch number, 2011-MD-0006).


Gaj P.,Silesian University of Technology | Jasperneite J.,Ostwestfalen-Lippe University of Applied Sciences | Felser M.,Berne University of Applied science
IEEE Transactions on Industrial Informatics | Year: 2013

Nowadays, computer systems are presented in almost all types of human activity and they support any kind of industry as well. Most of these systems are distributed where the communication between nodes is based on computer networks of any kind. Connectivity between system components is the key issue when designing distributed systems, especially systems of industrial informatics. The industrial area requires a wide range of computer communication means, particularly time-constrained and safety-enhancing ones. From fieldbus and industrial Ethernet technologies through wireless and internet-working solutions to standardization issues, there are many aspects of computer networks uses and many interesting research domains. Lots of them are quite sophisticated or even unique. The main goal of this paper is to present the survey of the latest trends in the communication domain of industrial distributed systems and to emphasize important questions as dependability, and standardization. Finally, the general assessment and estimation of the future development is provided. The presentation is based on the abstract description of dataflow within a system. © 2005-2012 IEEE.


Hehl S.,Berne University of Applied science | Vallee T.,Berne University of Applied science | Bai Y.,Ecole Polytechnique Federale de Lausanne
Key Engineering Materials | Year: 2010

Adhesively bonded connections involving pultruded FRP typically fail in a brittle manner, making their analysis a case study for the application of statistical size effects. For brittle materials, in which failure is often caused by a single critical defect, statistically based size effects on strength are adequately explained by probabilistic theories such as the Weibull strength theory. A previously implemented probabilistic dimensioning method for adhesively bonded balanced joints is extended to a complex joint involving a tube and a lamella, both made of pultruded FRP. Instead of the previously used 2d approach the extension requires a 3d formulation. The entire joint is idealized as being constituted by n elements; its survival depends on the simultaneous survival of all elements. By the means of a 3d FEA, failure triggering stress components in all n elements were determined; a probability of failure is associated to each element using the corresponding combination stresses combined into an appropriate failure criterion, hence defining a theoretical joint strength. © (2010) Trans Tech Publications, Switzerland.


Gusewell S.,Berne University of Applied science | Gusewell S.,ETH Zurich | Klotzli F.,ETH Zurich
Eco.mont | Year: 2012

Protected areas in the Alps are dissected by high-traffic roads for tourist access and transit. Road construction leaves disturbed areas with open soil, which may serve as starting points for the invasion of alien plants or ruderal lowland plants into the protected mountain habitats. In the 1960s, a transit road was widened in the Swiss National Park (SNP) and disturbed roadsides were sown with mixtures of grassland species. Roadside development and vegetation dynamics in the adjacent subalpine pine (Pinus mugo) forest were monitored in permanent plots from 1969 till 2010. Over the 42-year monitoring period, the sown species disappeared progressively and were replaced by species from naturally disturbed areas as well as by forest species. A standard seed mixture and native seeds introduced with local hay developed similarly. Sown species did not expand into the natural habitats and no alien species colonized the roadsides, despite the long-term persistence of open soil. The impact of roadsides on the local flora was therefore minimal. Ecological indicator values suggest that the development of roadsides in the SNP was determined by harsh conditions resulting from a continental subalpine climate and poorly developed soils on dolomite. Therefore, the developments observed in the SNP and the proposed low impact of roadsides on the natural vegetation may not hold for other Alpine regions with different geology and a more oceanic climate.


Ruegsegger M.B.,University of Bern | Geiser D.,Berne University of Applied science | Steiner P.,University of Bern | Pica A.,University of Bern | And 2 more authors.
Medical Physics | Year: 2014

Purpose: External beam radiation therapy is currently considered the most common treatment modality for intraocular tumors. Localization of the tumor and efficient compensation of tumor misalignment with respect to the radiation beam are crucial. According to the state of the art procedure, localization of the target volume is indirectly performed by the invasive surgical implantation of radiopaque clips or is limited to positioning the head using stereoscopic radiographies. This work represents a proof-of-concept for direct and noninvasive tumor referencing based on anterior eye topography acquired using optical coherence tomography (OCT). Methods: A prototype of a head-mounted device has been developed for automatic monitoring of tumor position and orientation in the isocentric reference frame for LINAC based treatment of intraocular tumors. Noninvasive tumor referencing is performed with six degrees of freedom based on anterior eye topography acquired using OCT and registration of a statistical eye model. The proposed prototype was tested based on enucleated pig eyes and registration accuracy was measured by comparison of the resulting transformation with tilt and torsion angles manually induced using a custom-made test bench. Results: Validation based on 12 enucleated pig eyes revealed an overall average registration error of 0.26 ± 0.08° in 87 ± 0.7 ms for tilting and 0.52 ± 0.03°in 94 ± 1.4 ms for torsion. Furthermore, dependency of sampling density on mean registration error was quantitatively assessed. Conclusions: The tumor referencing method presented in combination with the statistical eye model introduced in the past has the potential to enable noninvasive treatment and may improve quality, efficacy, and flexibility of external beam radiotherapy of intraocular tumors. © 2014 American Association of Physicists in Medicine.


Kaschesky M.,Berne University of Applied science | Riedl R.,Berne University of Applied science
Proceedings of the Annual Hawaii International Conference on System Sciences | Year: 2011

Linked social information on blogs and online social networks provides a rich source of policy feedback for citizens, journalists, politicians and researchers, yet the qualitative value hidden in this information is rarely exploited. In order to address the problem, this article presents a systematic methodology for retrieving targeted information on a political issue from prominent online sources. Using news services for triangulation, the methodology enables qualitative analysis regarding the spread of political opinions on an issue across a relevant sample of linked social information on the internet. The resulting pattern informs not only about the structure and information flows across linked social information but also about sentiments and opinion adoption over time. A model of opinion formation is presented and used to apply the methodology. © 2011 IEEE.


Hoigne D.,Cantonal Hospital Lucerne | Hauck R.,Berne University of Applied science | Babst R.,Cantonal Hospital Lucerne
Archives of Orthopaedic and Trauma Surgery | Year: 2011

Endomedullary femur nails with a head-neck implant offer an up to now unused point of reference for the determination of rotation during osteosynthesis. The lateral femur nail (LFN) or the long Proximal Femur Nail (long PFNA), for example, have recon screws or a blade placed at a 10°angle to the distal locking screw in the transversal plane. If the head-neck implant is inserted properly, the rotation of the femur can be measured with the C-arm taking the hole of the distal locking screw and the posterior condylar tangential line as reference lines. If the posterior condylar tangential line is parallel to the axes of the hole of the distal locking screw, then the rotation or anteversion of the femur is equal to the angle between the head-neck implant and the distal locking screw which is 10°with LFN or long PFNA. Differing rotation angles can be made visible by rotating the C-arm from the axial projection of the distal locking screw up to the posterior condylar tangential line. Three exemplary cases are presented. The recommended method was effective. The rotation of the femur can be measured intraoperatively with this technique and many revisions can be avoided. © 2011 Springer-Verlag.


Brugger J.,Berne University of Applied science | Fraefel M.,Berne University of Applied science | Riedl R.,Berne University of Applied science
Proceedings of the European Conference on e-Government, ECEG | Year: 2014

A common identification and authentication space is one of the goals set in Europe's Digital Agenda. Interoperability of electronic identities (eIDs) across Europe will facilitate mobility and cross-border e-business and therefore contribute to growth. Large Scale Pilots STORK and STORK 2.0 have designed a technical solution and are developing a model for offering cross-border eID use as service. A major challenge remains in growing acceptance for such a system by end users, service providers and national governments alike. This paper examines the different aspects influencing the long-term success of European identity federation, which enables cross-border eID use for accessing e-Government and private services. Based on a literature review, it offers a framework for analysing acceptance criteria according to different stakeholder groups (governments, service providers, end users). It takes into account the trust component, the mutual influence of acceptance decisions and the importance of contextual factors influencing the actors' choices. The discussion is based on a reflection of existing conceptual approaches in the field of technology acceptance in general and eID development in particular and draws on preliminary empirical data from the STORK 2.0 project. The paper outlines the challenges of creating a European interoperability solution, which allows a convergence with the development of national eID strategies and fits the value expectations of all stakeholders. In an organizational perspective, it touches upon requirements for creating an identity ecosystem with a network character but centralized services and decisions. In conclusion, the paper presents critical success factors for advanced collaboration between private service providers and government agencies across Europe on the subject of eID development. Thereby it assesses the current status of realization and outlines the challenges and opportunities ahead. © 2014 The Authors.

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