Recent additions

  • A waveguide imaging platform for live-cell TIRF imaging of neurons over large fields of view 

    Opstad, Ida Sundvor; Ströhl, Florian; Fantham, Marcus J.; Hockings, Colin; Vanderpoorten, Oliver; Tartwijk, Francesca W. van; Qiaojin Lin, Julie; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Kaminski‐Schierle, Gabriele S.; Ahluwalia, Balpreet Singh; Kaminski, Clemens F. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-17)
    Large fields of view (FOVs) in total internal reflection fluorescence microscopy (TIRFM) via waveguides have been shown to be highly beneficial for single molecule localisation microscopy on fixed cells [1,2] and have also been demonstrated for short‐term live‐imaging of robust cell types [3‐5], but not yet for delicate primary neurons nor over extended periods of time. Here, we present a waveguide‐based ...
  • Beyond the grid: The promise of solar concentration for non-electrical energy generation 

    Apostoleris, Harry; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-09)
    As electricity from both photovoltaics and concentrating solar power has become dramatically more affordable in the last several years, the prospect of converting entire national electrical grids to run almost entirely on renewable energy has become feasible in any location with a strong solar resource. However, focusing only on the electric grid neglects the large portion of our energy usage which ...
  • Label-free nanoscopy enabled by coherent imaging with photonic waveguides 

    Ströhl, Florian; Opstad, Ida Sundvor; Tinguely, Jean-Claude; Dullo, Firehun Tsige; Kaminski, Clemens F.; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-29)
    In this project it was found that Fourier ptychographic microscopy can be improved far beyond its conventional limits via waveguide-based optical systems. Extensive in silico studies showed that images obtained on highrefractive index material waveguide chips in conjunction with hyperspectral illumination light and finely designed waveguide geometries can be combined via a modified phase-retrieval ...
  • Effect on the longitudinal coherence properties of a pseudothermal light source as a function of source size and temporal coherence 

    Ahmad, Azeem; Mahanty, Tanmoy; Dubey, Vishesh; Butola, Ankit; Ahluwalia, Balpreet Singh; Mehta, Dalip Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-01)
    In the present Letter, a synthesized pseudothermal light source having high temporal coherence (TC) and low spatial coherence (SC) properties is used. The longitudinal coherence (LC) properties of the spatially extended monochromatic light source are systematically studied. The pseudothermal light source is generated from two different monochromatic laser sources: He–Ne (at 632 nm) and DPSS (at 532 ...
  • CHARGING AND DETECTION OF MESOSPHERIC DUST WITH INSTRUMENT SPID ON G-CHASER ROCKET 

    Gunnarsdottir, Tinna; Trollvik, Henriette; Mann, Ingrid; Olsen, Sveinung viggo; Eilertsen, Yngve; Antonsen, Tarjei; Björk, Arne; Restad, Erlend; Havnes, Ove; Fredriksen, Åshild; Boothby, Christoffer; Hansen, Rikke Hedelund; Floer, Markus (Journal article; Tidsskriftartikkel; Peer reviewed, 2019)
    The Smoke Particle Impact Detector (SPID) was flown on the G-Chaser student rocket that was launched from Andøya on 13 January 2019. SPID is a Faraday cup instrument with applied bias voltages to deflect the ambient plasma and a target area inside the probe designed to measure the dust particles by charge detection. The charging process of the dust particles in the detector is important for interpretation ...
  • Assessment of land subsidence using interferometric synthetic aperture radar time series analysis and artificial neural network in a geospatial information system: Case study of Rafsanjan Plain 

    Bagheri, Mohsen; Dehghani, Maryam; Esmaeily, Ali; Akbari, Vahid (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-31)
    Land subsidence resulting from groundwater extraction is a widely recurring phenomenon worldwide. To assess land subsidence, traditional methods such as numerical and finite element methods have limitations due to the complex interactions between the different constructor factors of aquifer in each area. We produced a groundwater-induced subsidence map by applying the geological and hydrogeological ...
  • Adaptive fluctuation imaging captures rapid subcellular dynamics 

    Opstad, Ida Sundvor; Ströhl, Florian; Birgisdottir, Åsa birna; Maldonado, Sebastián Andrés Acuña; Kalstad, Trine; Myrmel, Truls; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-22)
    In this work we have explored the live-cell friendly nanoscopy method Multiple Signal Classification Algorithm (MUSICAL) for multi-colour imaging of various organelles and sub-cellular structures in the cardiomyoblast cell line H2c9. We have tested MUSICAL for fast (up to 230Hz), multi-colour time-lapse sequences of various sub-cellular structures (mitochondria, endoplasmic reticulum, microtubules, ...
  • Direct growth of single-layer terminated vertical graphene array on germanium by plasma enhanced chemical vapor deposition 

    Al-Hagri, Abdulrahman; Li, Ru; Rajput, Nitul S; Lu, Jin-You; Cong, Shan; Sloyan, Karen; Almahri, Mariam Ali; Tamalampudi, Srinivasa Reddy; Chiesa, Matteo; Al Ghaferi, Amal (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-26)
    Vertically aligned graphene nanosheet arrays (VAGNAs) exhibit large surface area, excellent electron transport properties, outstanding mechanical strength, high chemical stability, and enhanced electrochemical activity, which makes them highly promising for application in supercapacitors, batteries, fuel cell catalysts, etc. It is shown that VAGNAs terminated with a high-quality single-layer graphene ...
  • Unsupervised Feature Extraction – A CNN-Based Approach 

    Trosten, Daniel Johansen; Sharma, Puneet (Peer reviewed; Book; Chapter, 2019-05-12)
    Working with large quantities of digital images can often lead to prohibitive computational challenges due to their massive number of pixels and high dimensionality. The extraction of compressed vectorial representations from images is therefore a task of vital importance in the field of computer vision. In this paper, we propose a new architecture for extracting such features from images in an ...
  • The 3‐D Distribution of Artificial Aurora Induced by HF Radio Waves in the Ionosphere 

    Kvammen, Andreas; Gustavsson, Björn Johan; Sergienko, Tima; Brändström, Urban; Rietveld, Michael T; Rexer, Theresa; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-21)
    We present 3‐D excitation rate estimates of artificial aurora in the ionospheric F layer, induced by high‐frequency radio waves from the European Incoherent Scatter heating facility. Simultaneous imaging of the artificial aurora was done with four separate Auroral Large Imaging System stations, permitting tomography‐like 3‐D auroral reconstruction of the enhanced atomic oxygen emissions at 6,300, ...
  • The Case for Combining a Large Low‐Band Very High Frequency Transmitter With Multiple Receiving Arrays for Geospace Research: A Geospace Radar 

    Hysell, David; Chau, Jorge Luis; Coles, William A; Milla, Marco; Obenberger, Kenneth; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-09)
    We argue that combining a high‐power, large‐aperture radar transmitter with several large‐aperture receiving arrays to make a geospace radar—a radar capable of probing near‐Earth space from the upper troposphere through to the solar corona—would transform geospace research. We review the emergence of incoherent scatter radar in the 1960s as an agent that unified early, pioneering research in geospace ...
  • Unsupervised Image Regression for Heterogeneous Change Detection 

    Luppino, Luigi Tommaso; Bianchi, Filippo Maria; Moser, Gabriele; Anfinsen, Stian Normann (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-14)
    Change detection (CD) in heterogeneous multitemporal satellite images is an emerging and challenging topic in remote sensing. In particular, one of the main challenges is to tackle the problem in an unsupervised manner. In this paper, we propose an unsupervised framework for bitemporal heterogeneous CD based on the comparison of affinity matrices and image regression. First, our method quantifies ...
  • Deep divergence-based approach to clustering 

    Kampffmeyer, Michael C.; Løkse, Sigurd; Bianchi, Filippo Maria; Livi, Lorenzo; Salberg, Arnt Børre; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-08)
    A promising direction in deep learning research consists in learning representations and simultaneously discovering cluster structure in unlabeled data by optimizing a discriminative loss function. As opposed to supervised deep learning, this line of research is in its infancy, and how to design and optimize suitable loss functions to train deep neural networks for clustering is still an open question. ...
  • High-concentration photovoltaics for dual-use with agriculture 

    Apostoleris, Harry; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-28)
    This study assesses the potential of transparent, tracking-integrated CPV to facilitate more effective dual-use of land for simultaneous agricultural and solar energy production. The concept leverages on the fact that a concentration system is a natural light splitter, separating direct solar radiation from the diffuse. Therefore a transparent CPV module using multijunction solar cells can generate ...
  • Episodically Active Asteroid 6478 Gault 

    Jewitt, David; Kim, Yoonyoung; Luu, Jane; Rajagopal, Jayadev; Kotulla, Ralf; Ridgway, Susan; Liu, Wilson (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-06)
    We present imaging and spectroscopic observations of 6478 Gault, a ~6 km diameter inner main-belt asteroid currently exhibiting strong, comet-like characteristics. Three distinct tails indicate that ultra-slow dust (ejection speed 0.15 ± 0.05 m s−1) was emitted from Gault in separate episodes beginning UT 2018 October 28 ± 5 (Tail A), UT 2018 December 31 ± 5 (Tail B), and UT 2019 February 10 ± 7 ...
  • Adaptive fluctuation imaging captures rapid subcellular dynamics 

    Opstad, Ida Sundvor; Ströhl, Florian; Birgisdottir, Åsa birna; Acuña Maldonado, Sebastian Andres; Kalstad, Trine; Myrmel, Truls; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel, 2019-07-22)
    In this work we have explored the live-cell friendly nanoscopy method Multiple Signal Classification Algorithm (MUSICAL) for multi-colour imaging of various organelles and sub-cellular structures in the cardiomyoblast cell line H2c9. We have tested MUSICAL for fast (up to 230Hz), multi-colour time-lapse sequences of various sub-cellular structures (mitochondria, endoplasmic reticulum, microtubules, ...
  • Subauroral and polar traveling ionospheric disturbances during 7-9 September 2017 storms 

    Zhang, Shunrong; Erickson, Philip j.; Coster, Anthea; Rideout, William; Vierinen, Juha; Jonah, Olusegun; Goncharenko, Larisa (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-25)
    This study provides new scenarios for storm time traveling ionospheric disturbance excitation and subsequent propagation at subauroral and polar latitudes. We used ground‐based total electron content observations from Global Navigation Satellite System receivers combined with wide field, subauroral ionospheric plasma parameters measured with the Millstone Hill Incoherent Scatter Radar during strong ...
  • The Discus Comet: C/2014 B1 (Schwartz) 

    Jewitt, David; Kim, Yoonyoung; Luu, Jane; Graykowski, Ariel (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-08)
    Long-period comet C/2014 B1 (Schwartz) exhibits a remarkable optical appearance, like that of a discus or bi-convex lens viewed edgewise. Our measurements in the four years since discovery reveal a unique elongated dust coma whose orientation is stable with respect to the projected antisolar and orbital directions. With no tail and no trail, the limited influence of radiation pressure on the dust ...
  • Machine learning assisted quantification of graphitic surfaces exposure to defined environments 

    Lai, Chia-Yun; Santos, Sergio; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-17)
    We show that it is possible to submit the data obtained from physical phenomena as complex as the tip-surface interaction in atomic force microscopy to a specific question of interest and obtain the answer irrespective of the complexity or unknown factors underlying the phenomena. We showcase the power of the method by asking “how many hours has this graphite surface been exposed to ambient conditions?” ...
  • A Novel Algorithm for Online Inexact String Matching and its FPGA Implementation 

    Cinti, Alessandro; Bianchi, Filippo Maria; Rizzi, Antonello (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-14)
    Among the basic cognitive skills of the biological brain in humans and other mammals, a fundamental one is the ability to recognize inexact patterns in a sequence of objects or events. Accelerating inexact string matching procedures is of utmost importance when dealing with practical applications where huge amounts of data must be processed in real time, as usual in bioinformatics or cybersecurity. ...

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