Christian Michelsen Research

Bergen, Norway

Christian Michelsen Research

Bergen, Norway
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Thomas P.J.,Christian Michelsen Research | Hellevang J.O.,Christian Michelsen Research
Sensors and Actuators, B: Chemical | Year: 2017

In this paper we describe the characteristics of a 64-m-long distributed relative humidity sensor with cm spatial resolution. The sensing element is an optical fibre with a hygroscopic coating that undergoes a reversible expansion on water uptake, thereby transferring a strain on the fibre. The resulting distributed strain profile was interrogated using Rayleigh backscatter based optical frequency domain reflectometry. Investigations of the distributed sensor under controlled relative humidity and temperature were carried out. The distributed sensor is strongly humidity sensitive when polyimide coated fibre is used, and only weakly sensitive when acrylate coating is used. When using polyimide coated fibre the distributed sensor shows a near linear response across the entire range of relative humidity tested covering 15–92%, with a sensitivity ∼1.3 μe/%RH and showing low hysteresis. The system is able to resolve relative humidity changes ∼0.1%. The response time of the sensor was found to be strongly dependent on temperature in the range tested, covering 30–50 °C. Using reference temperature and humidity measurements, it was demonstrated that the distributed sensor accurately reported the combined effects of temperature and humidity variations over a cm spatial scale. © 2017

Agency: European Commission | Branch: H2020 | Program: RIA | Phase: SFS-11a-2014 | Award Amount: 3.63M | Year: 2015

The AquaSpace project has the goal of providing increased space for aquaculture to allow increased production. Following the call, we will achieve this by identifying the key constraints experienced by aquaculture development in a wide range of contexts and aquaculture types, taking into account all relevant factors and advised by a Reference User Group. We will then map these constraints against a wide variety of tools/methods that have already been developed in national and EU projects for spatial planning purposes, including some that have been designed specifically for aquaculture. In the freshwater sector only, we will also consider ecosystem services provided by aquaculture that are relevant to integrated catchment planning and management. At 16 case study sites having a variety of scales, aquaculture at different trophic levels with different environmental interactions and most importantly with a range of key space-related development constraints as defined by local stakeholders, we will assess appropriate tools using a common process so as to facilitate synthesis and comparison. This case study approach will generate a large amount of information and is allocated about a third of the projects resources. The project will develop the outcomes leading to a set of evaluated tools for facilitating the aquaculture planning process by overcoming present constraints. This information will be presented on an interactive web-based platform with tailored entry points for specific user types (e.g. planners, farmers, public) to enable them to navigate to the tools most appropriate to their application. The knowledge and information gained during this process will be developed into an on-line module at Masters Level which will also be developed into a short CPD course aimed at aquaculture planning professionals. The public will be engaged by an innovative school video competition and a vehicle to ensure project legacy will be established.

Agency: European Commission | Branch: FP7 | Program: CP | Phase: OCEAN 2013.2 | Award Amount: 8.10M | Year: 2013

As stated by the marine research decision makers in Europe in the Ostend Declaration in 2010, a major challenge is to support the development of a truly integrated and sustainably funded European Ocean Observing System. This will be achieved with more long-term measurements of key parameters but is impaired by the costs and lack of reliability of ocean sensors in general. The NeXOS project aims to improve the temporal and spatial coverage, resolution and quality of marine observations through the development of cost-efficient innovative and interoperable in-situ sensors deployable from multiple platforms, and Web Services for key domains and applications. This will be achieved through the development of new, low-cost, compact and integrated sensors with multiple functionalities including the measurement of key parameters useful to a number of objectives, ranging from more precise monitoring and modelling of the marine environment to an improved assessment of fisheries. Seven new compact, cost-efficient sensors will be developed, based on optical and acoustics technologies, addressing a majority of descriptors identified by the Marine Strategy Framework Directive for Good Environmental Status. Two of the new sensors will specifically contribute to the Common Fisheries Policy with variables relevant for an Ecosystem Approach to Fisheries. All new sensors will respond to multiplatform integration, sensor and data interoperability, quality assurance and reliability requirements. These will be specified for each new sensor system. All new sensors will be calibrated, integrated on several types of platforms, scientifically validated and demonstrated. One of the main objectives of NeXOS will finally be to enhance the competitiveness of European SMEs in the ocean sensor market. To this end, sensor requirements and specifications will be assessed at an early phase of the project for market penetration.

Agency: European Commission | Branch: H2020 | Program: RIA | Phase: BG-06-2014 | Award Amount: 7.79M | Year: 2015

BRIDGES (Bringing together Research and Industry for the Development of Glider Environmental Services) will provide a necessary tool for further understanding, improved monitoring, and responsible exploitation of the marine environment while assuring its long-term preservation. This new tool, a robust, cost-effective, re-locatable, versatile and easily-deployed ocean glider, will support autonomous, long-term in-situ exploration of the deep ocean at large spatio-temporal scales. The sole European underwater glider: SeaExplorer will be modularized, new sensors will be developed, and the operational methodology will be modified, such that new horizons of service will be opened. It will be improved by: 1) adapting for deep basins (up to 5000 m), 2) implementing a novel payload architecture to increase autonomy and to accommodate the range of sensing capabilities needed, and 3) integrating the associated control support system for single and networked operations (mission behaviour, data management, planning, communications). The gliders sensing capabilities will be enhanced. The main modules are planned for: 1) environmental monitoring for facilitating the effective implementation of an ecosystem-based management under the Marine Strategy Framework Directive, 2) the oil and gas industry, and 3) the deep sea mining industry. In order to achieve the technological objectives and meet service requirements, an open dialogue between stakeholders will be developed. The basic premises of the present call Delivering sub-sea technologies for new services at sea-BG-06-2014, are answered thoroughly: the ability to execute unmanned underwater operations, to operate in the deep ocean, and to assess the environmental impact of the maritime economy. In addition, this project will realize and promote the creation of collaborations among sensor and platform manufacturers, oil and gas and mining companies, public health and safety departments, and scientific and engineering experts.

Patel D.,Christian Michelsen Research | Bruckner S.,Vienna University of Technology | Viola I.,University of Bergen | Groller E.M.,Vienna University of Technology
IEEE Pacific Visualization Symposium 2010, PacificVis 2010 - Proceedings | Year: 2010

Seismic horizons indicate change in rock properties and are central in geoscience interpretation. Traditional interpretation systems involve time consuming and repetitive manual volumetric seeding for horizon growing. We present a novel system for rapidly interpreting and visualizing seismic volumetric data. First we extract horizon surface-parts by preprocessing the seismic data. Then during interaction the user can assemble in realtime the horizon parts into horizons. Traditional interpretation systems use gradient-based illumination models in the rendering of the seismic volume and polygon rendering of horizon surfaces. We employ realtime gradientfree forward-scattering in the rendering of seismic volumes yielding results similar to high-quality global illumination. We use an implicit surface representation of horizons allowing for a seamless integration of horizon rendering and volume rendering. We present a collection of novel techniques constituting an interpretation and visualization system highly tailored to seismic data interpretation. ©2010 IEEE.

Sandve T.H.,University of Bergen | Berre I.,University of Bergen | Berre I.,Christian Michelsen Research | Nordbotten J.M.,University of Bergen | Nordbotten J.M.,Princeton University
Journal of Computational Physics | Year: 2012

We consider a control volume discretization with a multi-point flux approximation to model Discrete Fracture-Matrix systems for anisotropic and fractured porous media in two and three spatial dimensions. Inspired by a recently introduced approach based on a two-point flux approximation, we explicitly account for the fractures by representing them as hybrid cells between the matrix cells. As well as simplifying the grid generation, our hybrid approach excludes small cells in the intersection of the fractures and hence avoids severe time-step restrictions associated with small cells. Excluding the small cells also reduces the condition number of the discretization matrix. For examples involving realistic anisotropy ratios in the permeability, numerical results show significant improvement compared to existing methods based on two-point flux approximations. We also investigate the hybrid method by studying the convergence rates for different apertures and fracture/matrix permeability ratios. Finally, the effect of removing the cells in the intersections of the fractures are studied. Together, these examples demonstrate the efficiency, flexibility and robustness of our new approach. © 2012 Elsevier Inc.

Solteszova V.,University of Bergen | Patel D.,Christian Michelsen Research | Bruckner S.,Simon Fraser University | Viola I.,University of Bergen
Computer Graphics Forum | Year: 2010

In this paper, we present a novel technique which simulates directional light scattering for more realistic interactive visualization of volume data. Our method extends the recent directional occlusion shading model by enabling light source positioning with practically no performance penalty. Light transport is approximated using a tilted cone-shaped function which leaves elliptic footprints in the opacity buffer during slice-based volume rendering. We perform an incremental blurring operation on the opacity buffer for each slice in front-to-back order. This buffer is then used to define the degree of occlusion for the subsequent slice. Our method is capable of generating high-quality soft shadowing effects, allows interactive modification of all illumination and rendering parameters, and requires no pre-computation. © 2010 The Eurographics Association and Blackwell Publishing Ltd.

Solteszova V.,Christian Michelsen Research | Patel D.,Christian Michelsen Research | Viola I.,Christian Michelsen Research
NPAR Symposium on Non-Photorealistic Animation and Rendering | Year: 2011

Soft shadows are effective depth and shape cues. However, traditional shadowing algorithms decrease the luminance in shadow areas. The features in shadow become dark and thus shadowing causes information hiding. For this reason, in shadowed areas, medical illustrators decrease the luminance less and compensate the lower luminance range by adding color, i.e., by introducing a chromatic component. This paper presents a novel technique which enables an interactive setup of an illustrative shadow representation for preventing overdarkening of important structures. We introduce a scalar attribute for every voxel denoted as shadowiness and propose a shadow transfer function that maps the shadowiness to a color and a blend factor. Typically, the blend factor increases linearly with the shadowiness. We then let the original object color blend with the shadow color according to the blend factor. We suggest a specific shadow transfer function, designed together with a medical illustrator which shifts the shadow color towards blue. This shadow transfer function is quantitatively evaluated with respect to relative depth and surface perception. © 2011 ACM.

You J.,Christian Michelsen Research | Ebrahimi T.,Ecole Polytechnique Federale de Lausanne | Perkis A.,Norwegian University of Science and Technology
IEEE Transactions on Image Processing | Year: 2014

Contrast sensitivity of the human visual system to visual stimuli can be significantly affected by several mechanisms, e.g., vision foveation and attention. Existing studies on foveation based video quality assessment only take into account static foveation mechanism. This paper first proposes an advanced foveal imaging model to generate the perceived representation of video by integrating visual attention into the foveation mechanism. For accurately simulating the dynamic foveation mechanism, a novel approach to predict video fixations is proposed by mimicking the essential functionality of eye movement. Consequently, an advanced contrast sensitivity function, derived from the attention driven foveation mechanism, is modeled and then integrated into a wavelet-based distortion visibility measure to build a full reference attention driven foveated video quality (AFViQ) metric. AFViQ exploits adequately perceptual visual mechanisms in video quality assessment. Extensive evaluation results with respect to several publicly available eye-tracking and video quality databases demonstrate promising performance of the proposed video attention model, fixation prediction approach, and quality metric. © 1992-2012 IEEE.

You J.,Christian Michelsen Research
2013 IEEE China Summit and International Conference on Signal and Information Processing, ChinaSIP 2013 - Proceedings | Year: 2013

User experience plays a crucial role in emerging multimedia services. Traditional Quality of Service (QoS) criteria have been demonstrated to be not adequately accurate to measure and manage the user viewing experience when consuming multimedia content. Recently Quality of Experience (QoE), a quality criterion purely driven by subjective cognition, has been defined to evaluate the overall acceptability of a service. As a perceptual concept, QoE is influenced by internal and external factors. In order to effectively manage visual QoE for multimedia services, visual attention, an integral mechanism of the human perceptual system, should be integrated into QoE definition, assessment, and improvement. This paper systematically presents visual QoE management methodologies driven by attention mechanism. © 2013 IEEE.

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