Change search
Refine search result
1234567 1 - 50 of 4506
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    A. Hosseini, Vahid
    et al.
    University West, Sweden ; Innovatum AB, Sweden.
    Karlsson, Leif
    University West, Sweden.
    Örnek, Cem
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB. KTH Royal Institute of Technology, Sweden.
    Reccagni, Pierfrance
    The University of Manchester, UK.
    Wessman, Sten
    University West, Sweden.
    Engelberg, Dirk
    The University of Manchester, UK.
    Microstructure and functionality of a uniquely graded super duplex stainless steel designed by a novel arc heat treatment method2018In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 139, p. 390-400Article in journal (Refereed)
    Abstract [en]

    A novel arc heat treatment technique was applied to design a uniquely graded super duplex stainless steel (SDSS), by subjecting a single sample to a steady state temperature gradient for 10 h. A new experimental approach was used to map precipitation in microstructure, covering aging temperatures of up to 1430 °C. The microstructure was characterized and functionality was evaluated via hardness mapping. Nitrogen depletion adjacent to the fusion boundary depressed the upper temperature limit for austenite formation and influenced the phase balance above 980 °C. Austenite/ferrite boundaries deviating from Kurdjumov–Sachs orientation relationship (OR) were preferred locations for precipitation of σ at 630–1000 °C, χ at 560–1000 °C, Cr2N at 600–900 °C and R between 550 °C and 700 °C. Precipitate morphology changed with decreasing temperature; from blocky to coral-shaped for σ, from discrete blocky to elongated particles for χ, and from polygonal to disc-shaped for R. Thermodynamic calculations of phase equilibria largely agreed with observations above 750 °C when considering nitrogen loss. Formation of intermetallic phases and 475 °C-embrittlement resulted in increased hardness. A schematic diagram, correlating information about phase contents, morphologies and hardness, as a function of exposure temperature, is introduced for evaluation of functionality of microstructures. 

  • 2.
    Aadland, Reidun C.
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Dziuba, Carter J.
    University of Calgary, Canada.
    Heggset, Ellinor B
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Syverud, Kristin
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Torsæter, Ole
    NTNU Norwegian University of Science and Technology, Norway.
    Holt, Thorleif
    SINTEF, Norway.
    Gates, Ian D.
    University of Calgary, Canada.
    Bryant, Steven L.
    University of Calgary, Canada.
    Identification of nanocellulose retention characteristics in porous media2018In: Nanomaterials, ISSN 2079-4991, Vol. 8, no 7, article id 547Article in journal (Refereed)
    Abstract [en]

    The application of nanotechnology to the petroleum industry has sparked recent interest in increasing oil recovery, while reducing environmental impact. Nanocellulose is an emerging nanoparticle that is derived from trees or waste stream from wood and fiber industries. Thus, it is taken from a renewable and sustainable source, and could therefore serve as a good alternative to current Enhanced Oil Recovery (EOR) technologies. However, before nanocellulose can be applied as an EOR technique, further understanding of its transport behavior and retention in porous media is required. The research documented in this paper examines retention mechanisms that occur during nanocellulose transport. In a series of experiments, nanocellulose particles dispersed in brine were injected into sandpacks and Berea sandstone cores. The resulting retention and permeability reduction were measured. The experimental parameters that were varied include sand grain size, nanocellulose type, salinity, and flow rate. Under low salinity conditions, the dominant retention mechanism was adsorption and when salinity was increased, the dominant retention mechanism shifted towards log-jamming. Retention and permeability reduction increased as grain size decreased, which results from increased straining of nanocellulose aggregates. In addition, each type of nanocellulose was found to have significantly different transport properties. Experiments with Berea sandstone cores indicate that some pore volume was inaccessible to the nanocellulose. As a general trend, the larger the size of aggregates in bulk solution, the greater the observed retention and permeability reduction. Salinity was found to be the most important parameter affecting transport. Increased salinity caused additional aggregation, which led to increased straining and filter cake formation. Higher flow rates were found to reduce retention and permeability reduction. Increased velocity was accompanied by an increase in shear, which is believed to promote breakdown of nanocellulose aggregates. © 2018 by the authors.

  • 3.
    Aadland, Reidun
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Jakobsen, Trygve
    NTNU Norwegian University of Science and Technology, Norway.
    Heggset, Ellinor B
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Long-Sanouiller, Haili
    NTNU Norwegian University of Science and Technology, Norway.
    Simon, Sebastien
    NTNU Norwegian University of Science and Technology, Norway.
    Paso, Kristofer
    NTNU Norwegian University of Science and Technology, Norway.
    Syverud, Kristin
    RISE - Research Institutes of Sweden, Bioeconomy, PFI. NTNU Norwegian University of Science and Technology, Norway.
    Torsæter, Ole
    NTNU Norwegian University of Science and Technology, Norway.
    High-temperature core flood investigation of nanocellulose as a green additive for enhanced oil recovery2019In: Nanomaterials, ISSN 2079-4991, Vol. 9, no 5, article id 665Article in journal (Refereed)
    Abstract [en]

    Recent studies have discovered a substantial viscosity increase of aqueous cellulose nanocrystal (CNC) dispersions upon heat aging at temperatures above 90 °C. This distinct change in material properties at very low concentrations in water has been proposed as an active mechanism for enhanced oil recovery (EOR), as highly viscous fluid may improve macroscopic sweep efficiencies and mitigate viscous fingering. A high-temperature (120 °C) core flood experiment was carried out with 1 wt.% CNC in low salinity brine on a 60 cm-long sandstone core outcrop initially saturated with crude oil. A flow rate corresponding to 24 h per pore volume was applied to ensure sufficient viscosification time within the porous media. The total oil recovery was 62.2%, including 1.2% oil being produced during CNC flooding. Creation of local log-jams inside the porous media appears to be the dominant mechanism for additional oil recovery during nano flooding. The permeability was reduced by 89.5% during the core flood, and a thin layer of nanocellulose film was observed at the inlet of the core plug. CNC fluid and core flood effluent was analyzed using atomic force microscopy (AFM), particle size analysis, and shear rheology. The effluent was largely unchanged after passing through the core over a time period of 24 h. After the core outcrop was rinsed, a micro computed tomography (micro-CT) was used to examine heterogeneity of the core. The core was found to be homogeneous. © 2019 by the authors.

  • 4.
    Aaen, Ragnhild
    et al.
    Norwegian University of Science and Technology, Norway.
    Brodin, Fredrik Wernersson
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Simon, Sébastien
    Norwegian University of Science and Technology, Norway.
    Heggset, Ellinor B
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Syverud, Kristin
    RISE - Research Institutes of Sweden, Bioeconomy, PFI. Norwegian University of Science and Technology, Norway.
    Oil-in-Water Emulsions Stabilized by Cellulose Nanofibrils-The Effects of Ionic Strength and pH.2019In: Nanomaterials (Basel, Switzerland), ISSN 2079-4991, Vol. 9, no 2, article id E259Article in journal (Refereed)
    Abstract [en]

    Pickering o/w emulsions prepared with 40 wt % rapeseed oil were stabilized with the use of low charged enzymatically treated cellulose nanofibrils (CNFs) and highly charged 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized CNFs. The emulsion-forming abilities and storage stability of the two qualities were tested in the presence of NaCl and acetic acid, at concentrations relevant to food applications. Food emulsions may be an important future application area for CNFs due to their availability and excellent viscosifying abilities. The emulsion characterization was carried out by visual inspection, light microscopy, viscosity measurements, dynamic light scattering and mild centrifugation, which showed that stable emulsions could be obtained for both CNF qualities in the absence of salt and acid. In addition, the enzymatically stabilized CNFs were able to stabilize emulsions in the presence of acid and NaCl, with little change in the appearance or droplet size distribution over one month of storage at room temperature. The work showed that enzymatically treated CNFs could be suitable for use in food systems where NaCl and acid are present, while the more highly charged TEMPO-CNFs might be more suited for other applications, where they can contribute to a high emulsion viscosity even at low concentrations.

  • 5.
    Aaen, Ragnhild
    et al.
    Norwegian University of Science and Technology, Norway.
    Simon, Sebastien
    Norwegian University of Science and Technology, Norway.
    Wernersson Brodin, Fredrik
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Syverud, Kristin
    RISE - Research Institutes of Sweden, Bioeconomy, PFI. Norwegian University of Science and Technology, Norway.
    The potential of TEMPO-oxidized cellulose nanofibrils as rheology modifiers in food systems2019In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 9, p. 5483-5496Article in journal (Refereed)
    Abstract [en]

    Abstract: Cellulose nanofibrils (CNFs) have been proposed for use in low-fat food products due to their availability and excellent viscosifying and gel forming abilities. As the CNFs are negatively charged, the presence of other components in foods, such as electrolytes and food additives such as xanthan gum is likely to affect their rheological properties. Hence, the study of these interactions can contribute valuable information of the suitability of CNFs as rheology modifiers and fat replacers. Rheological measurements on aqueous dispersions of TEMPO-oxidized CNFs were performed with variations in concentration of CNFs, concentration of electrolytes and with varying CNF/xanthan ratios. UV–Vis Spectroscopy was used to evaluate the onset of CNF flocculation/aggregation in the presence of electrolytes. The CNF dispersions followed a power-law dependency for viscosity and moduli on CNF concentration. Low electrolyte additions strengthened the CNF network by allowing for stronger interactions, while higher additions led to fibril aggregation, and loss of viscosity, especially under shear. The CNF/xanthan ratio, as well as the presence of electrolytes were shown to be key factors in determining whether the viscosity and storage modulus of CNF dispersions increased or decreased when xanthan was added. Graphical abstract: [Figure not available: see fulltext.].

  • 6.
    Aarstad, Olav
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Heggset, Ellinor B
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Pedersen, Ina Sander
    NTNU Norwegian University of Science and Technology, Norway.
    Björnöy, Sindre H.
    NTNU Norwegian University of Science and Technology, Norway.
    Syverud, Kristin
    RISE - Research Institutes of Sweden, Bioeconomy, PFI.
    Strand, Berit L.
    NTNU Norwegian University of Science and Technology, Norway.
    Mechanical properties of composite hydrogels of alginate and cellulose nanofibrils2017In: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 9, no 8, article id 378Article in journal (Refereed)
    Abstract [en]

    Alginate and cellulose nanofibrils (CNF) are attractive materials for tissue engineering and regenerative medicine. CNF gels are generally weaker and more brittle than alginate gels, while alginate gels are elastic and have high rupture strength. Alginate properties depend on their guluronan and mannuronan content and their sequence pattern and molecular weight. Likewise, CNF exists in various qualities with properties depending on, e.g., morphology and charge density. In this study combinations of three types of alginate with different composition and two types of CNF with different charge and degree of fibrillation have been studied. Assessments of the composite gels revealed that attractive properties like high rupture strength, high compressibility, high gel rigidity at small deformations (Young’s modulus), and low syneresis was obtained compared to the pure gels. The effects varied with relative amounts of CNF and alginate, alginate type, and CNF quality. The largest effects were obtained by combining oxidized CNF with the alginates. Hence, by combining the two biopolymers in composite gels, it is possible to tune the rupture strength, Young’s modulus, syneresis, as well as stability in physiological saline solution, which are all important properties for the use as scaffolds in tissue engineering.

  • 7.
    Abbas, Mohammad
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Inayat, Irum
    National University of Computer & Emerging Sciences, Pakistan.
    Saadatmand, Mehrdad
    RISE - Research Institutes of Sweden, ICT, SICS.
    Jan, Naila
    National University of Computer & Emerging Sciences, Pakistan.
    Requirements dependencies-based test case prioritization for extra-functional properties2019In: Proceedings - 2019 IEEE 12th International Conference on Software Testing, Verification and Validation Workshops, ICSTW 2019, Institute of Electrical and Electronics Engineers Inc. , 2019, p. 159-163Conference paper (Refereed)
    Abstract [en]

    The use of requirements' information in testing is a well-recognized practice in the software development life cycle. Literature reveals that existing tests prioritization and selection approaches neglected vital factors affecting tests priorities, like interdependencies between requirement specifications. We believe that models may play a positive role in specifying these inter-dependencies and prioritizing tests based on these inter-dependencies. However, till date, few studies can be found that make use of requirements inter-dependencies for test case prioritization. This paper uses a meta-model to aid modeling requirements, their related tests, and inter-dependencies between them. The instance of this meta-model is then processed by our modified PageRank algorithm to prioritize the requirements. The requirement priorities are then propagated to related test cases in the test model and test cases are selected based on coverage of extra-functional properties. We have demonstrated the applicability of our proposed approach on a small example case.

  • 8.
    Abbas, Zainab
    et al.
    KTH Royal Institute of Technology, Sweden.
    Al-Shishtawy, Ahmad
    RISE - Research Institutes of Sweden, ICT, SICS.
    Girdzijauskas, Sarunas
    RISE - Research Institutes of Sweden, ICT, SICS. KTH Royal Institute of Technology, Sweden.
    Vlassov, Vladimir
    KTH Royal Institute of Technology, Sweden.
    Short-Term Traffic Prediction Using Long Short-Term Memory Neural Networks2018In: Proceedings - 2018 IEEE International Congress on Big Data, BigData Congress 2018 - Part of the 2018 IEEE World Congress on Services, Institute of Electrical and Electronics Engineers Inc. , 2018, p. 57-65Conference paper (Refereed)
    Abstract [en]

    Short-term traffic prediction allows Intelligent Transport Systems to proactively respond to events before they happen. With the rapid increase in the amount, quality, and detail of traffic data, new techniques are required that can exploit the information in the data in order to provide better results while being able to scale and cope with increasing amounts of data and growing cities. We propose and compare three models for short-term road traffic density prediction based on Long Short-Term Memory (LSTM) neural networks. We have trained the models using real traffic data collected by Motorway Control System in Stockholm that monitors highways and collects flow and speed data per lane every minute from radar sensors. In order to deal with the challenge of scale and to improve prediction accuracy, we propose to partition the road network into road stretches and junctions, and to model each of the partitions with one or more LSTM neural networks. Our evaluation results show that partitioning of roads improves the prediction accuracy by reducing the root mean square error by the factor of 5. We show that we can reduce the complexity of LSTM network by limiting the number of input sensors, on average to 35% of the original number, without compromising the prediction accuracy. .

  • 9.
    Abbas, Zainab
    et al.
    KTH Royal Institute of Technology, Sweden.
    Sigurdsson, Thorsteinn
    KTH Royal Institute of Technology, Sweden.
    Al-Shishtawy, Ahmad
    RISE - Research Institutes of Sweden, ICT, SICS.
    Vlassov, Vladimir
    KTH Royal Institute of Technology, Sweden.
    Evaluation of the use of streaming graph processing algorithms for road congestion detection2018In: Proceedings - 16th IEEE International Symposium on Parallel and Distributed Processing with Applications, 17th IEEE International Conference on Ubiquitous Computing and Communications, 8th IEEE International Conference on Big Data and Cloud Computing, 11th IEEE International Conference on Social Computing and Networking and 8th IEEE International Conference on Sustainable Computing and Communications, ISPA/IUCC/BDCloud/SocialCom/SustainCom 2018, Institute of Electrical and Electronics Engineers Inc. , 2018, p. 1017-1025Conference paper (Refereed)
    Abstract [en]

    Real-time road congestion detection allows improving traffic safety and route planning. In this work, we propose to use streaming graph processing algorithms for road congestion detection and evaluate their accuracy and performance. We represent road infrastructure sensors in the form of a directed weighted graph and adapt the Connected Components algorithm and some existing graph processing algorithms, originally used for community detection in social network graphs, for the task of road congestion detection. In our approach, we detect Connected Components or communities of sensors with similarly weighted edges that reflect different states in the traffic, e.g., free flow or congested state, in regions covered by detected sensor groups. We have adapted and implemented the Connected Components and community detection algorithms for detecting groups in the weighted sensor graphs in batch and streaming manner. We evaluate our approach by building and processing the road infrastructure sensor graph for Stockholm's highways using real-world data from the Motorway Control System operated by the Swedish traffic authority. Our results indicate that the Connected Components and DenGraph community detection algorithms can detect congestion with accuracy up to ? 94% for Connected Components and up to ? 88% for DenGraph. The Louvain Modularity algorithm for community detection fails to detect congestion regions for sparsely connected graphs, representing roads that we have considered in this study. The Hierarchical Clustering algorithm using speed and density readings is able to detect congestion without details, such as shockwaves.

  • 10.
    Abbasi, Abdul Gahafoor
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Khan, Zaheer
    University of the West of England, UK.
    Veidblock: Verifiable identity using blockchain and ledger in a software defined network2017In: UCC 2017 Companion - Companion Proceedings of the 10th International Conference on Utility and Cloud Computing, Association for Computing Machinery, Inc , 2017, p. 173-179Conference paper (Refereed)
    Abstract [en]

    Blockchain and verifiable identities have a lot of potential in future distributed software applications e.g. smart cities, eHealth, autonomous vehicles, networks, etc. In this paper, we proposed a novel technique, namely VeidBlock 1 , to generate verifiable identities by following a reliable authentication process. These entities are managed by using the concepts of blockchain ledger and distributed through an advance mechanism to protect them against tampering. All identities created using VeidBlock approach are verifiable and anonymous therefore it preserves user’s privacy in verification and authentication phase. As a proof of concept, we implemented and tested the VeidBlock protocols by integrating it in a SDN based infrastructure. Analysis of the test results yield that all components successfully and autonomously performed initial authentication and locally verified all the identities of connected components.

  • 11.
    Abdelraheem, Mohamed Ahmed
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Andersson, Tobias
    RISE - Research Institutes of Sweden, ICT, SICS.
    Gehrmann, Christian
    Lund university, Sweden.
    Searchable Encrypted Relational Databases:Risks and Countermeasures2017In: Data Privacy Management, Cryptocurrencies and Blockchain Technology: ESORICS 2017 International Workshops, DPM 2017 and CBT 2017, Oslo, Norway, September 14-15, 2017, Proceedings / [ed] Joaquin Garcia-Alfaro et al., Gewerbestrasse 11, 6330 Cham, Switzerland: Springer Nature , 2017, Vol. 10436, p. 70-85Conference paper (Refereed)
    Abstract [en]

    We point out the risks of protecting relational databases viaSearchable Symmetric Encryption (SSE) schemes by proposing an infer-ence attack exploiting the structural properties of relational databases.We show that record-injection attacks mounted on relational databaseshave worse consequences than their file-injection counterparts on un-structured databases. Moreover, we discuss some techniques to reducethe effectiveness of inference attacks exploiting the access pattern leak-age existing in SSE schemes. To the best of our knowledge, this is thefirst work that investigates the security of relational databases protectedby SSE schemes.

  • 12.
    Abdelraheem, Mohamed
    et al.
    Intelligent Voice Ltd, UK.
    Andersson, Tobias
    RISE - Research Institutes of Sweden, ICT, SICS.
    Gehrmann, Christian
    Lund University, Sweden.
    Glackin, Cornelius
    Intelligent Voice Ltd, UK.
    Practical Attacks on Relational Databases Protected via Searchable Encryption2018In: Lecture Notes in Computer Science, 2018, p. 171-191Conference paper (Refereed)
    Abstract [en]

    Searchable symmetric encryption (SSE) schemes are commonly proposed to enable search in a protected unstructured documents such as email archives or any set of sensitive text files. However, some SSE schemes have been recently proposed in order to protect relational databases. Most of the previous attacks on SSE schemes have only targeted its common use case, protecting unstructured data. In this work, we propose a new inference attack on relational databases protected via SSE schemes. Our inference attack enables a passive adversary with only basic knowledge about the meta-data information of the target relational database to recover the attribute names of some observed queries. This violates query privacy since the attribute name of a query is secret.

  • 13.
    Abitbol, Tiffany
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Impact of surface charge on CNC phase separation and rheology2017In: International Conference on Nanotechnology for Renewable Materials 2017, TAPPI Press , 2017, p. 64-71Conference paper (Refereed)
  • 14.
    Abitbol, Tiffany
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy, Biorefinery and Energy.
    Ahniyaz, Anwar
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Swerin, Agne
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    UV-blocking hybrid nanocellulose films containing ceria and silica nanoparticles2018In: International Conference on Nanotechnology for Renewable Materials 2018, 2018, p. 503-515Conference paper (Refereed)
  • 15.
    Abitbol, Tiffany
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation. The Hebrew University of Jerusalem, Israel.
    Kam, Doron
    The Hebrew University of Jerusalem, Israel.
    Levi-Kalisman, Yael
    The Hebrew University of Jerusalem, Israel.
    Gray, Derek G
    McGill University, Canada.
    Shoseyov, Oded
    The Hebrew University of Jerusalem, Israel.
    Surface Charge Influence on the Phase Separation and Viscosity of Cellulose Nanocrystals2018In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 34, no 13, p. 3925-3933Article in journal (Refereed)
    Abstract [en]

    counterions in the suspensions. The results suggest that there is a threshold surface charge density (∼0.3%S) above which effective volume considerations are dominant across the concentration range relevant to liquid crystalline phase formation. Above this threshold value, phase separation occurs at the same effective volume fraction of CNCs (∼10 vol %), with a corresponding increase in critical concentration due to the decrease in effective diameter that occurs with increasing surface charge. Below or near this threshold value, the formation of end-to-end aggregates may favor gelation and interfere with ordered phase formation.

  • 16.
    Abitbol, Tobias
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Ahniyaz, Anwar
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Swerin, Agne
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    UV-blocking hybrid nanocellulose films containing ceria and silica nanoparticles2018In: International Conference on Nanotechnology for Renewable Materials 2018, 2018, p. 503-515Conference paper (Refereed)
  • 17.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Alonso, Juan
    RISE - Research Institutes of Sweden, ICT, SICS.
    Andersson, Anders
    RISE - Research Institutes of Sweden, ICT, SICS.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    A Multi Path Routing Algorithm for IP Networks Based on Flow Optimisation.2002Conference paper (Refereed)
  • 18.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Alonso, Juan
    RISE - Research Institutes of Sweden, ICT, SICS.
    Andersson, Anders
    RISE - Research Institutes of Sweden, ICT, SICS.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    From QoS provisioning to QoS charging2002In: Proceedings of the Second International Workshop on Internet Charging and QoS Technologies, ICQT 2002, 2002, 1, Vol. Lectures Notes in Computer Science (LNCS) no. 2511, p. 135-144Conference paper (Refereed)
  • 19.
    Abrahamsson, Henrik
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ahlgren, Bengt
    RISE - Research Institutes of Sweden, ICT, SICS.
    Lindvall, Patrik
    TeliaSonera, Sweden.
    Nieminen, Johanna
    TeliaSonera, Sweden.
    Tholin, Per
    TeliaSonera, Sweden.
    Traffic Characteristics on 1Gbit/s Access Aggregation Links2017Conference paper (Refereed)
    Abstract [en]

    Large network operators have thousands or tens of thousands of access aggregation links that they need to manage and dimension properly. Measuring and understanding the traffic characteristics on these type of links are therefore essential. What do the traffic intensity characteristics look like on different timescales from days down to milliseconds? How do the characteristics differ if we compare links with the same capacity but with different type of clients and access technologies? How do the traffic characteristics differ from that on core network links? These are the type of questions we set out to investigate in this paper. We present the results of packet level measurements on three different 1Gbit/s aggregation links in an operational IP network. We see large differences in traffic characteristics between the three links. We observe highly skewed link load probability densities on timescales relevant for buffering (i.e. 10-milliseconds). We demonstrate the existence of large traffic spikes on short timescales (10-100ms) and show their impact on link delay. We also found that these traffic bursts often are caused by only one or a few IP flows.

  • 20.
    Abrahamsson, Henrik
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ben Abdesslem, Fehmi
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ahlgren, Bengt
    RISE - Research Institutes of Sweden, ICT, SICS.
    Björkman, Mats
    Mälardalen University, Sweden.
    Brunstrom, Anna
    Karlstad University, Sweden.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Selecting Operator in 3G/4G Networks for Time-Critical C-ITS Applications2018Conference paper (Refereed)
  • 21.
    Abrahamsson, Henrik
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ben Abdesslem, Fehmi
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ahlgren, Bengt
    RISE - Research Institutes of Sweden, ICT, SICS.
    Brunstrom, Anna
    Karlstad University, Sweden.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Björkman, Mats
    Mälardalen University, Sweden.
    Connected Vehicles in Cellular Networks: Multi-access versus Single-access Performance2018Conference paper (Refereed)
    Abstract [en]

    Connected vehicles can make roads traffic safer andmore efficient, but require the mobile networks to handle timecriticalapplications. Using the MONROE mobile broadbandmeasurement testbed we conduct a multi-access measurementstudy on buses. The objective is to understand what networkperformance connected vehicles can expect in today’s mobilenetworks, in terms of transaction times and availability. The goalis also to understand to what extent access to several operatorsin parallel can improve communication performance.In our measurement experiments we repeatedly transfer warningmessages from moving buses to a stationary server. Wetriplicate the messages and always perform three transactionsin parallel over three different cellular operators. This creates adataset with which we can compare the operators in an objectiveway and with which we can study the potential for multi-access.In this paper we use the triple-access dataset to evaluate singleaccessselection strategies, where one operator is chosen for eachtransaction. We show that if we have access to three operatorsand for each transaction choose the operator with best accesstechnology and best signal quality then we can significantlyimprove availability and transaction times compared to theindividual operators. The median transaction time improves with6% compared to the best single operator and with 61% comparedto the worst single operator. The 90-percentile transaction timeimproves with 23% compared to the best single operator andwith 65% compared to the worst single operator.

  • 22.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Hagsand, Olof
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    TCP over High Speed Variable Capacity Links: A Simulation Study for Bandwidth Allocation2002Conference paper (Refereed)
  • 23.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    DTMsim - DTM channel simulation in ns2001Report (Other academic)
    Abstract [en]

    Dynamic Transfer Mode (DTM) is a ring based MAN technology that provides a channel abstraction with a dynamically adjustable capacity. TCP is a reliable end to end transport protocol capable of adjusting its rate. The primary goal of this work is investigate the coupling of dynamically allocating bandwidth to TCP flows with the affect this has on the congestion control mechanism of TCP. In particular we wanted to find scenerios where this scheme does not work, where either all the link capacity is allocated to TCP or congestion collapse occurs and no capacity is allocated to TCP. We have created a simulation environment using ns-2 to investigate TCP over networks which have a variable capacity link. We begin with a single TCP Tahoe flow over a fixed bandwidth link and progressively add more complexity to understand the behaviour of dynamically adjusting link capacity to TCP and vice versa.

  • 24.
    Abrahamsson, Tobias
    et al.
    Linköping University, Sweden.
    Poxson, David J
    Linköping University, Sweden.
    Gabrielsson, Erik O
    Linköping University, Sweden.
    Sandberg, Mats
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Simon, Daniel T
    Linköping University, Sweden.
    Berggren, Magnus
    Linköping University, Sweden.
    Formation of Monolithic Ion-Selective Transport Media Based on "Click" Cross-Linked Hyperbranched Polyglycerol.2019In: Frontiers in chemistry, ISSN 2296-2646, Vol. 7, article id 484Article in journal (Refereed)
    Abstract [en]

    In the emerging field of organic bioelectronics, conducting polymers and ion-selective membranes are combined to form resistors, diodes, transistors, and circuits that transport and process both electronic and ionic signals. Such bioelectronics concepts have been explored in delivery devices that translate electronic addressing signals into the transport and dispensing of small charged biomolecules at high specificity and spatiotemporal resolution. Manufacturing such "iontronic" devices generally involves classical thin film processing of polyelectrolyte layers and insulators followed by application of electrolytes. This approach makes miniaturization and integration difficult, simply because the ion selective polyelectrolytes swell after completing the manufacturing. To advance such bioelectronics/iontronics and to enable applications where relatively larger molecules can be delivered, it is important to develop a versatile material system in which the charge/size selectivity can be easily tailormade at the same time enabling easy manufacturing of complex and miniaturized structures. Here, we report a one-pot synthesis approach with minimal amount of organic solvent to achieve cationic hyperbranched polyglycerol films for iontronics applications. The hyperbranched structure allows for tunable pre multi-functionalization, which combines available unsaturated groups used in crosslinking along with ionic groups for electrolytic properties, to achieve a one-step process when applied in devices for monolithic membrane gel formation with selective electrophoretic transport of molecules.

  • 25.
    Achtel, Christian
    et al.
    Friedrich Schiller University of Jena, Germany.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden, Materials and Production, IVF. Friedrich Schiller University of Jena, Germany.
    Kosan, Birgit
    TITK Thuringian Institute of Textile and Plastics Research, Germany.
    Seoud, Omar. A.El
    University of São Paulo, Brazil.
    Heinze, Thomas
    Friedrich Schiller University of Jena, Germany.
    Dissolution capacity of novel cellulose solvents based on triethyloctylammonium chloride2017In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 218, no 21, article id 1700208Article in journal (Refereed)
    Abstract [en]

    Dissolution of cellulose from various sources (microcrystalline cellulose and different dissolving grade pulp fibers) is investigated in solvent systems based on triethyl(n-octyl)ammonium chloride (N2228Cl). Clear cellulose solutions are obtained with N2228Cl in a variety of solvents, e.g., dimethyl sulfoxide, N,N-dimethylacetamide, and acetone. It is possible to prepare clear cellulose solutions from pulp fibers with concentrations up to 15 wt%. However, it is found that the cellulose is degraded, especially when neat (i.e., molten) N2228Cl is used as a solvent. The present work includes comprehensive rheological characterization of the cellulose solutions, both with shear and extensional rheology. In most cases, the viscosity values are low (complex viscosities below 100 Pa s for 5–10 wt% dissolved cellulose), and the solutions show more Newtonian than viscoelastic behavior. 

  • 26.
    Achtel, Christian
    et al.
    Friedrich Schiller University Jena, Germany.
    Jedvert, Kerstin
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Kostag, Marc
    University of Sao Paulo, Brazil.
    El Seoud, Omar A.
    University of Sao Paulo, Brazil.
    Heinze, Thomas
    Friedrich Schiller University Jena, Germany.
    Surprising Insensitivity of Homogeneous Acetylation of Cellulose Dissolved in Triethyl(n-octyl)ammonium Chloride/Molecular Solvent on the Solvent Polarity2018In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 303, no 5Article in journal (Refereed)
    Abstract [en]

    The homogeneous acetylation of microcrystalline cellulose (MCC) by acetyl chloride and acetic anhydride in triethyl(n-octyl)ammonium chloride (N2228Cl)/molecular solvents (MSs) is investigated. The reaction with both acylating agents shows the expected increase of the degree of substitution (DS) on reaction temperature and time. Under comparable reaction conditions, however, DS is surprisingly little dependent on the MS employed, although the MSs differ in empirical polarity by 7 kcal mol−1 as calculated by use of solvatochromic probes. The empirical polarities of (MCC + N2228Cl + MS) differ only by 0.8 kcal mol−1. The formation a polar electrolyte sheath around cellulose chains presumably contributes to this “leveling-off” of the dependence DS on the polarity of the parent MS employed. N2228Cl recovery and recycling is feasible. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  • 27.
    Adler, Daniel
    RISE - Research Institutes of Sweden, ICT, SICS.
    Virtual Audio - Three-Dimensional Audio in Virtual Environments1996Report (Other academic)
    Abstract [en]

    Three-dimensional interactive audio has a variety ofpotential uses in human-machine interfaces. After lagging seriously behind the visual components, the importance of sound is now becoming increas-ingly accepted. This paper mainly discusses background and techniques to implement three-dimensional audio in computer interfaces. A case study of a system for three-dimensional audio, implemented by the author, is described in great detail. The audio system was moreover integrated with a virtual reality system and conclusions on user tests and use of the audio system is presented along with proposals for future work at the end of the paper. The thesis begins with a definition of three-dimensional audio and a survey on the human auditory system to give the reader the needed knowledge of what three-dimensional audio is and how human auditory perception works.

  • 28.
    Adolfsson, Erik
    RISE - Research Institutes of Sweden, Materials and Production, IVF, Keramer.
    Zirconia in applications with bone contact2016Conference paper (Other academic)
  • 29.
    Adolfsson, Erik
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Lyckfeldt, Ola
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Johansson, Emil
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Visible-Light Curable Ceramic Suspensions for Additive Manufacturing of Dense Ceramic Parts2016Conference paper (Other academic)
  • 30.
    Adolfsson, Erik
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Shen, J.Z.
    Stockholm University.
    Defect Minimization in Prosthetic Ceramics2014In: Advanced Ceramics for Dentistry, Elsevier Inc. , 2014, p. 359-373Chapter in book (Refereed)
    Abstract [en]

    The mechanical reliability and aesthetic appearance of ceramic dental prostheses are strongly influenced by the presence of defects. When several processes are used during fabrication of ceramic dental prostheses, additional defects are unavoidably introduced in each process step; these are in addition to the ones that already exist in raw materials. To avoid the degeneration of material performance by the accumulated defect population, process optimization is needed to minimize the defects introduced. Standardized mechanical evaluations are usually performed on samples with carefully prepared surfaces in order to minimize the influence from the defects usually induced by fabrication processes. The results from such mechanical evaluation indicate the strength level that is achievable by the material with the given population of bulk defects. In order to avoid a reduction in the performance of the ceramic material by the additional defects normally induced by the fabrication process, it must be understood how these defects are introduced, and solutions must be found to reduce their size and frequency through modifications of the material and processes. The aim of this chapter is to elucidate the sources of defects that are common for ceramic dental prostheses and to determine how to minimize them. © 2014 Elsevier Inc. All rights reserved.

  • 31.
    Adolfsson, Erik
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Shen, Z.
    Stockholm University.
    Effects of granule density on strength and granule related defects in zirconia2012In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 32, no 11, p. 2653-2659Article in journal (Refereed)
    Abstract [en]

    A suspension of zirconia powder (TZ3YSE) with a solids loading of 50. vol% was prepared by ball milling. Binders were added and some of the suspension was diluted to 40, 30 and 20. vol% before freeze granulation was performed. A spray dried material (TZ3YSEB) was used as a reference. The pore size distribution of the different granules was evaluated and from the microstructure it was shown that inhomogeneities were present in both the freeze granulated as well as in the spray dried granules. In addition, the density, microstructure as well as the strength of sintered materials prepared from the granules were studied. The results showed that a high green density or sintered density was not sufficient in order to achieve a high strength material. It was further shown that the strength was significantly influenced by the granule density and not by the inhomogeneities found in the granules. © 2012.

  • 32.
    Adolfsson, Erik
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Tönnäng, Lenny
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    The effect of softmachining parameters on the mechanical strength of zirconia2015Conference paper (Other academic)
  • 33.
    Adolfsson, Erik
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, IVF.
    Venturini, Francesca
    ZHAW School of Engineering, Switzerland.
    Schönherr, Veit
    ZHAW School of Engineering, Switzerland .
    Rey, Julien
    ZHAW School of Engineering, Switzerland .
    Characterization oflight-gas interaction in strongly-scattering nanoporous materials and itsimplications for tunable diode laser absorption spectroscopy2016In: Applied Physics B: Lasers and Optics, 2016, Vol. 123, p. 123-136Conference paper (Other academic)
    Abstract [en]

    Through the confinement of gas in nanoporous materials, it is possible to significantly increase the path length for light–gas interaction. This enables the observation of much stronger absorption features for the confined gas molecules. In this work, we systematically characterized a variety of disordered strongly scattering ZrO2 and Al2O3 nanoporous ceramic materials to exploit the potential of gas in scattering media absorption spectroscopy. As a result, we identified a material with an unprecedented performance in terms of optical path length enhancement. In ZrO2 with thicknesses above 6 mm, the path enhancement exceeds 1000. The results obtained with near-infrared absorption spectroscopy on oxygen were validated by time-of-flight measurements at 700 nm, thus demonstrating their robustness. Finally, we report quantitative oxygen concentration measurement using nanoporous materials as miniaturized random-scattering multipass cell with an extremely simple and low-cost setup.

  • 34.
    Afanasov, Mikhail
    et al.
    Politecnico di Milano, Italy.
    Iavorskii, Aleksandr
    John Wiley & Sons Inc, Russia.
    Mottola, Luca
    RISE - Research Institutes of Sweden, ICT, SICS. Politecnico di Milano, Italy.
    Programming Support for Time-sensitive Adaptation in Cyberphysical Systems2018In: ACM SIGBED Review, Vol. 14, no 4, p. 27-32Article in journal (Refereed)
    Abstract [en]

    Cyberphysical systems (CPS) integrate embedded sensors,actuators, and computing elements for controlling physicalprocesses. Due to the intimate interactions with thesurrounding environment, CPS software must continuouslyadapt to changing conditions. Enacting adaptation decisionsis often subject to strict time requirements to ensure controlstability, while CPS software must operate within the tightresource constraints that characterize CPS platforms. Developersare typically left without dedicated programmingsupport to cope with these aspects. This results in either toneglect functional or timing issues that may potentially ariseor to invest significant efforts to implement hand-crafted solutions.We provide programming constructs that allow developersto simplify the specification of adaptive processingand to rely on well-defined time semantics. Our evaluationshows that using these constructs simplifies implementationswhile reducing developers’ effort, at the price of a modestmemory and processing overhead.

  • 35.
    Afanasov, Mikhail
    et al.
    Politecnico di Milano, Italy.
    Mottola, Luca
    RISE - Research Institutes of Sweden, ICT, SICS. Politecnico di Milano, Italy.
    Ghezzi, Carlo
    Politecnico di Milano, Italy.
    Software Adaptation in Wireless Sensor Networks2018In: ACM Transactions on Autonomous and Adaptive Systems, Vol. 12, no 4, p. 1-29Article in journal (Refereed)
    Abstract [en]

    We present design concepts, programming constructs, and automatic verification techniques to support thedevelopment of adaptive Wireless Sensor Network (WSN) software. WSNs operate at the interface betweenthe physical world and the computing machine, and are hence exposed to unpredictable environment dynamics.WSN software must adapt to these dynamics to maintain dependable and efficient operation. Whilesignificant literature exists on the necessary adaptation logic, developers are left without proper support inmaterializing such a logic in a running system. Our work fills this gap with three key contributions: i) designconcepts help developers organize the necessary adaptive functionality and understand their relations,ii) dedicated programming constructs simplify the implementations, iii) custom verification techniques allowdevelopers to check the correctness of their design before deployment. We implement dedicated toolsupport to tie the three contributions, facilitating their practical application. Our evaluation considers representativeWSN applications to analyze code metrics, synthetic simulations, and cycle-accurate emulationof popular WSN platforms. The results indicate that our work is effective in simplifying the developmentof adaptive WSN software; for example, implementations are provably easier to test and to maintain, therun-time overhead of our dedicated programming construct is negligible, and our verification techniquesreturn results in a matter of seconds.

  • 36.
    Aghaeinezhadfirouzja, Saeid
    et al.
    Shanghai Jiao Tong University, China.
    Liu, Hui
    Shanghai Jiao Tong University, China.
    Balador, Ali
    RISE - Research Institutes of Sweden, ICT, SICS. Mälardalen University, Sweden.
    Practical 3-D beam pattern based channel modeling for multi-polarized massive MIMO systems2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 4, article id 1186Article in journal (Refereed)
    Abstract [en]

    In this paper, a practical non-stationary three-dimensional (3-D) channel models for massive multiple-input multiple-output (MIMO) systems, considering beam patterns for different antenna elements, is proposed. The beam patterns using dipole antenna elements with different phase excitation toward the different direction of travels (DoTs) contributes various correlation weights for rays related towards/from the cluster, thus providing different elevation angle of arrivals (EAoAs) and elevation angle of departures (EAoDs) for each antenna element. These include the movements of the user that makes our channel to be a non-stationary model of clusters at the receiver (RX) on both the time and array axes. In addition, their impacts on 3-D massive MIMO channels are investigated via statistical properties including received spatial correlation. Additionally, the impact of elevation/azimuth angles of arrival on received spatial correlation is discussed. Furthermore, experimental validation of the proposed 3-D channel models on azimuth and elevation angles of the polarized antenna are specifically evaluated and compared through simulations. The proposed 3-D generic models are verified using relevant measurement data.

  • 37.
    Agyei-Amponsah, Joyce
    et al.
    University of Pretoria, South Africa.
    Macakova, Lubica
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    DeKock, Henrietta
    University of Pretoria, South Africa.
    Emmambux, Mohammad
    University of Pretoria, South Africa.
    Sensory, Tribological, and Rheological Profiling of “Clean Label” Starch–Lipid Complexes as Fat Replacers2019In: Starke (Weinheim), ISSN 0038-9056, E-ISSN 1521-379X, article id 1800340Article in journal (Refereed)
    Abstract [en]

    Dietary fat is highlighted as one of the critical risk factors that contribute to a number of chronic diseases. In this study, the sensory profile, tribological, and rheological properties of starch–lipid complexes, as a potential fat replacer, is investigated. Starch–lipid complexes are formulated by incorporating food friendly chemicals (stearic acid and monoglyceride) into maize starch by wet-heat processing and compared with a commercial fat replacer. The starch–lipid complexes have good lubricating properties and are described by the panelists as being glossy, smooth, creamy, and easy-to-swallow. All the complexes exhibited a shear thinning behavior and had lower firmness, due to their non-gelling ability compared to the commercial fat replacer. The properties of starch–lipid complexes for non-gelling, good lubricating, smooth, and creamy can be related to the formation of amylose–lipid complexes and other properties. The complexes have the potential to produce non-gelling emulsions having a creamy and smooth texture with no adverse effect on the overall aroma and flavor.

  • 38.
    Ahlberg-Eliasson, Karin
    et al.
    Swedish Rural Economy and Agricultural Society, Sweden.
    Nadeau, Elisabet
    Swedish Rural Economy and Agricultural Society, Sweden; SLU Swedish University of Agricultural Sciences, Sweden.
    Levén, Lotta
    RISE - Research Institutes of Sweden, Bioscience and Materials, Agrifood and Bioscience.
    Schnürer, Anna
    SLU Swedish University of Agricultural Sciences, Sweden.
    Production efficiency of Swedish farm-scale biogas plants2017In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 97, p. 27-37Article in journal (Refereed)
    Abstract [en]

    Biogas from agricultural waste streams represents an important way to produce fossil-free energy, allow nutrient recycling and reduce greenhouse gas emissions. However, biogas production from agricultural substrates is currently far from reaching its full potential. In Sweden, the number of biogas plants and their output have increased in recent years, but they are still experiencing harsh economic conditions. A recent evaluation (2010–2015) of 31 farm-scale biogas production facilities in Sweden sought to identify parameters of importance for further positive development. In this paper, data on plant operation, gas yield and digestate quality for 27 of these plants are summarised and statistically analysed to investigate factors that could allow an increase in overall biogas production and in nutrient content in the digestate. The analysis showed that addition of co-substrates to manure results in higher gas production, expressed as both specific methane potential and volumetric gas production, than when manure is the sole substrate. Use of co-substrate was also found to be influential for the nutrient content of the digestate. These observed improvements caused by co-digestion should be considered when subsidy systems for manure-based biogas processes are being created, as they could also improve the economics of biogas production. However, to achieve higher efficiency in existing biogas plants and to improve the situation for future investments, a more detailed, long-term evaluation programme should also be considered.

  • 39.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Andersson, Anders
    Hagsand, Olof
    RISE - Research Institutes of Sweden, ICT, SICS.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Dimensioning links for IP telephony2001In: Proceedings of the 2nd IP-Telephony Workshop (IPtel 2001), 2-3 April 2001, New York City, New York, USA, 2001, 1Conference paper (Refereed)
    Abstract [en]

    Packet loss is an important parameter for dimensioning network links or traffic classes carrying IP telephony traffic. We present a model based on the Markov modulated Poisson process (MMPP) which calculates packet loss probabilities for a set of super positioned voice input sources and the specified link properties. We do not introduce another new model to the community, rather try and verify one of the existing models via extensive simulation and a real world implementation. A plethora of excellent research on queuing theory is still in the domain of ATM researchers and we attempt to highlight its validity to the IP Telephony community. Packet level simulations show very good correspondence with the predictions of the model. Our main contribution is the verification of the MMPP model with measurements in a laboratory environment. The loss rates predicted by the model are in general close to the measured loss rates and the loss rates obtained with simulation. The general conclusion is that the MMPP-based model is a tool well suited for dimensioning links carrying packetized voice in a system with limited buffer space.

  • 40.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Andersson, Anders
    RISE - Research Institutes of Sweden, ICT, SICS.
    Hagsand, Olof
    RISE - Research Institutes of Sweden, ICT, SICS.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Dimensioning Links for IP Telephony2000Report (Other academic)
    Abstract [en]

    Transmitting telephone calls over the Internet causes problems not present in current telephone technology such as packet loss and delay due to queueing in routers. In this undergraduate thesis we study how a Markov modulated Poisson process is applied as an arrival process to a multiplexer and we study the performance in terms of loss probability. The input consists of the superposition of independent voice sources. The predictions of the model is compared with results obtained with simulations of the multiplexer made with a network simulator. The buffer occupancy distribution is also studied and we see how this distribution changes as the load increases.

  • 41.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Gunningberg, Per
    RISE - Research Institutes of Sweden, ICT, SICS.
    The applicability of integrated layer processing1998In: IEEE Journal on Selected Areas in Communications, Vol. 16, no 3, p. 317-331Article in journal (Refereed)
    Abstract [en]

    In this paper we review previous work on the applicability and performance of Integrated Layer Processing (ILP). ILP has been shown to clearly improve computer communication performance when integrating simple data manipulation functions, but the situation has been less clear for more complex functions and complete systems. We discuss complications when applying ILP to protocol stacks, the requirements of ILP on the communication subsystem, caching aspects, the importance of the processor registers, and a model for predicting the performance of data manipulation functions. We conclude that the main drawback of ILP is its limited aplicability to complex data manipulation functions. The performance to expect from an ILP implementation also depends heavily on the protocol architecture and the host system architecture.

  • 42.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Gunningberg, Per
    RISE - Research Institutes of Sweden, ICT, SICS.
    Towards predictable ILP performance-controlling communication buffer cache effects1995Conference paper (Refereed)
  • 43.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    D’Ambrosio, Matteo
    4WARD.
    Dannewitz, Christian
    4WARD.
    Marchisio, Marco
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ohlman, Börje
    Pentikousis, Kostas
    Rembarz, René
    Strandberg, Ove
    Vercellone, Vinicio
    Design considerations for a network of information2008Conference paper (Refereed)
    Abstract [en]

    The existing Internet ecosystem is a result of decades of evolution. It has managed to scale well beyond the original aspirations. Evolution, though, highlighted a certain degree of inadequacies that is well documented. In this position paper we present the design considerations for a re-architected global networking architecture which delivers dissemination and non-dissemination objects only to consenting recipients, reducing unwanted traffic, linking information producers with consumers independently of the hosts involved, and connects the digital with the physical world. We consider issues ranging from the proposed object identifier/locator split to security and trust as we transition towards a Network of Information and relate our work with the emerging paradigm of publish/subscribe architectures. We introduce the fundamental components of a Network of Information, i.e., name resolution, routing, storage, and search, and close this paper with a discussion about future work.

  • 44.
    Ahlgren, Bengt
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Grinnemo, Karl-Johan
    Karlstad University, Sweden.
    Abrahamsson, Henrik
    RISE - Research Institutes of Sweden, ICT, SICS.
    Brunstrom, Anna
    Karlstad University, Sweden.
    Hurtig, Per
    Karlstad University, Sweden.
    Latency-aware Multipath Scheduling in Information-centric Networks2019In: Proceedings of the 15th Swedish National Computer Networking Workshop (SNCNW), 2019Conference paper (Other academic)
    Abstract [en]

    We present the latency-aware multipath scheduler ZQTRTT that takes advantage of the multipath opportunities in information-centric networking. The goal of the scheduler is to use the (single) lowest latency path for transaction-oriented flows, and use multiple paths for bulk data flows. A new estimator called zero queue time ratio is used for scheduling over multiple paths. The objective is to distribute the flow over the paths so that the zero queue time ratio is equal on the paths, that is, so that each path is ‘pushed’ equally hard by the flow without creating unwanted queueing. We make an initial evaluation using simulation that shows that the scheduler meets our objectives.

  • 45.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Gunningberg, Per
    RISE - Research Institutes of Sweden, ICT, SICS.
    Moldeklev, Kjersti
    Increasing communication performance with a minimal-copy data path supporting ILP and ALF1996In: Journal of High Speed Networks, Vol. 5, no 2, p. 203-214Article in journal (Refereed)
    Abstract [en]

    Many current implementations of communication subsystems on workstation class computers transfer communication data to and from primary memory several times. This is due to software copying between user and operating system address spaces, presentation layer data conversion and other data manipulation functions. The consequence is that memory bandwidth is one of the major performance bottlenecks limiting high speed communication on these systems. We propose a communication subsystem architecture with a minimal-copy data path to widen this bottleneck. The architecture is tailored for protocol implementations using Integrated Layer Processing (ILP) and Application Layer Framing (ALF). We choose to implement these protocols in the address space of the application program. We present a new application program interface (API) between the protocols and the communication service in the operating system kernel. The API does not copy data, but instead passes pointers to page size data buffers. We analyze and discuss ILP loop and cache memory requirements on these buffers. Initial experiments show that the API can increase the communication performance with 50% compared to a standard BSD Unix socket interface.

  • 46.
    Ahlgren, Bengt
    et al.
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Hurtig, Per
    Karlstad University, Sweden.
    Abrahamsson, Henrik
    RISE - Research Institutes of Sweden, ICT, Acreo.
    Grinnemo, Karl-Johan
    Karlstad University, Sweden.
    Brunstrom, Anna
    Karlstad University, Sweden.
    ICN congestion control for wireless links2018Conference paper (Refereed)
    Abstract [en]

    Information-centric networking (ICN) with its design around named-based forwarding and in-network caching holds great promises to become a key architecture for the future Internet. Many proposed ICN hop-by-hop congestion control schemes assume a fixed and known link capacity, which rarely - if ever - holds true for wireless links. Firstly, we demonstrate that although these congestion control schemes are able to fairly well utilise the available wireless link capacity, they greatly fail to keep the delay low. In fact, they essentially offer the same delay as in the case with no hop-by-hop, only end-to-end, congestion control. Secondly, we show that by complementing these schemes with an easy-to-implement, packet-train capacity estimator, we reduce the delay to a level significantly lower than what is obtained with only end-to-end congestion control, while still being able to keep the link utilisation at a high level.

  • 47.
    Ahlroth, Mikael
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy.
    Bialik, Marta
    RISE - Research Institutes of Sweden, Bioeconomy. RISE, Innventia.
    Jansson, Mikael
    RISE - Research Institutes of Sweden, Bioeconomy. Andritz, Sweden.
    Rosenqvist, Kristian
    ÅF, Sweden.
    Bark and wood powder firing in the recovery boiler for maximum power generation2017In: International chemical recovery conference, May 24-26, 2017, Halifax, Canada, PAPTAC , 2017Conference paper (Refereed)
    Abstract [en]

    The effect of co-firing bark or wood powder in a recovery boiler is studied. The effect of increased NPEs in the liquor and lime cycles, the FMT and sticky dust and the smelt composition is assessed by using simulation tools. The results indicate that generating an additional 22-39% HP steam for power production by firing wood powder in the recovery boiler is a viable option, if Cl and K are purged from the ESP dust by a treatment unit. The smelt is enriched with the same proportion of NPEs as the as-fired liquor.

  • 48.
    Ahlroth, Mikael
    et al.
    RISE - Research Institutes of Sweden, Bioeconomy.
    Bialik, Marta
    RISE - Research Institutes of Sweden, Bioeconomy.
    Jensen, Anna
    RISE - Research Institutes of Sweden, Bioeconomy.
    Hydrothermal carbonisation of effluent sludge2017In: The 7th Nordic Wood Biorefinery Conference held in Stockholm, Sweden, 28-30 Mar. 2017: NWBC 2017, Stockholm: RISE Bioekonomi , 2017, p. 156-158Conference paper (Refereed)
    Abstract [en]

    Research was carried out to investigate hydrothermal carbonisation (HTC) treatment of different effluent sludges from the pulp and paper industry in a Parr-reactor. Sludge samples were evaluated from a thermomechanical paper (TMP) mill and a kraft market pulp mill (NSWBK). The issues studied included HTC treatment time; addition of acid and alkali; dewatering properties of the resulting slurry; and non-process element (NPE) concentration in the original sludge, the filtrate and the filter cake. It was found that HTC improved the fuel quality. Alkali metals were depleted in TMP and NSWBK sludge and in both cases, the sludge was easier to dewater. The yield was better for TMP than NSWBK sludge and the yield losses had a negative impact on the NSWBK sludge. TMP sludge was already a viable boiler fuel and the treatment improved the fuel qualities even more. The HTC treatment of the NSWBK sludge resulted in lower chlorine and potassium, with lower fuel-nitrogen resulting in lower nitrous oxide. Although HTC treatment improved the low heating value of the sludge, this was counteracted by yield loss. Compared with untreated NSWBK, the overall energy impact was negative. HTC treatment offered mixed opportunities from the viewpoint of the recovery cycle.

  • 49.
    Ahlström, Johan
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Aluminium i betong - Litteraturstudie och experimentella försök2012Report (Refereed)
    Abstract [sv]

    I dagens byggprojekt används en mängd olika material för att bygga konstruktioner. Det förekommer att komponenter av aluminium gjuts in i betong vilket medför en risk att täckskiktet spricker p.g.a. korrosionsprodukternas stora volym. Därför är det viktigt att klargöra vilka korrosionsegenskaper aluminium har ingjuten i betong.

  • 50.
    Ahlström, Johan
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Atmosfäriska korrosionsegenskaper för rostfritt stål med olika ytstruktur2011Report (Refereed)
    Abstract [sv]

    Generellt sett så har rostfria stål en hög korrosionsresistens i atmosfärisk miljö p.g.a. den mycket tunna oxidfilmen på ytan, en film som fungerar som en barriär och försvårar initieringen av en korrosionsprocess på stålets yta. Dock så kan rostfria stål få svåra gropfrätningsangrepp i vissa aggressiva atmosfärer där t.ex. klorider och SO2 finns närvarande. Olika ytstrukturer kan ge ytan olika egenskaper som vätbarhet, ytråhet och ytsammansättning. En yta som har hög vätbarhet har en tjockare fuktfilm på ytan jämfört med en yta som har låg vätbarhet. Det är i fuktfilmen på ytan som korrosionsprocesserna sker, aggressiva partiklar och gaser kan tas upp i fuktfilmen från atmosfären och öka korrosionshastigheten. Ytråheten påverkar både vätbarhet och hur mycket partiklar som fastnar på en yta, därmed påverkar ytråheten korrosionshastigheten. Ytsammansättning anger vilka och hur mycket det finns av ett ämne i den skyddande oxidfilmen, ämnen som kan ha betydelse för hur lätt korrosion uppstår, t.ex. så kan olika sulfider fungera som initieringsyta för korrosionsangrepp. I litteraturen har det dragits olika slutsatser om vilken ytegenskap som har störst betydelse för korrosionens omfattning. Vissa studier säger att ytråheten har störst betydelse medan andra säger att ytsammansättningen har störst betydelse. Särskilt låglegerade ferritiska rostfria stål kan få svår gropfrätning i aggressiva miljöer och då har typen av ytstruktur liten betydelse för hur stora korrosionsangreppen blir. För de mer legerade austenitiska stålen kan typen av ytstruktur ha stor betydelse för storleken på korrosionsangrepp. Höglegerade stål som innehåller molybden har generellt sett små korrosionsangrepp och typen av ytstruktur har liten betydelse för korrosionsangreppens omfattning. Sammantaget tycks det dock vara så att ytråheten ändå har relativt stor inverkan på korrosionsresistensen, dock har relativt få studier genomförts där ytråheten verkligen mätts.

1234567 1 - 50 of 4506
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
v. 2.35.7